US2558219A - Snap acting device - Google Patents

Description

E. F'4 KOHL.

SNAP-ACTING DEVICE June 26, 1951 3 Sheets-Sheet l Filed March 14, 1941 INVENTOR Everard l". Kohl ATTORNEY Kohl 3 Sheets-Sheet 2 E. F. KOHL SNAP-ACTING DEVICE June 26, 1951v F11ed Maren 14, 1941 June 26, 1951 E. F. Kol-1l.

SNAP-ACTING DEVICE 3 Sheets-Sheet 3 Filed March 14, 1941 INVENTOR Verarol I'. Kohl .En BY Mm? ATroRNl-:Y

l'atented June Z6, 1951 UNITED STATES PATENT OFFICE 24 Claims.

My invention relates to devices in which a member to be actuated may be moved with a snap action for any desirable purpose and is a continuation in part of my application, Serial No. 214,923 filed on June 21, 1938, which has matured into Patent No. 2,237,705. More particularly, it relates to electrical switches of the Snap acting type.

Snap acting devices which have heretofore been utilized in apparatus, such as switches, valves, thermostats, relays and the like, are either somewhat complicated in structure or are lacking in the sensitivity which is required in certain apparatus of this type. It is the aim of the present invention to provide an improved snap acting device that may be utilized in various apparatus and which is sensitive in operation, economical to manufacture and has a comparatively long life in service.

My invention also contemplates providing a snap acting device in which the force required to operate the device may be regulated. A whiplike effect is also provided which enables the device to be actuated by a comparatively small movement of an actuating force and which assures positive action even when the device is utilized in apparatus, such as switches, which are adapted to be operated at high speed to make and break circuits. Improved means are also provided to limit or adjust the pretravel of the actuating -force and to limit its travel after actuation to thereby provide a device which is eXremely sensitive in operation.

It is therefore an object of my invention to provide an improved snap acting device that is simple in construction, sensitive in operation, and which has a comparatively long life in service.

Another object of my invention is to provide an improved snap acting device in which an arm which may constitute either the actuating member or the member to be actuated may be thrown with a whip-like action.

A further object of my invention is to provide an improved snap acting device which when actuated in one direction will return to its original position when the actuating force is removed.

Another object of my invention is to provide an improved snap acting switch of the momentary contact type in which a momentary contact is provided or in which a contact is momentarily broken.

A further object of my invention is to provide an improved snap acting device in which the pressure required to operate the device may be regulated.

Another object of my invention is to provide an improved snap acting switch which may be positively actuated by a comparatively short movement of an actuating -force operating upon an arm which is adapted to be thrown with a whip-like action to assure positive actuation of the device although the force is intermittently applied to repeatedly make and break circuits at high speeds.

A still further object of my invention is to provide an improved switch of the snap acting type which may be electrically or thermostatically operated.

Further objects and advantages of my invention Will be apparent as the specication proceeds.

My invention will be better understood by referring to the accompanying drawings in which:

Fig. 1 is a side elevational view of one form of my improved switch, showing the position of the parts after yforce has been applied in the direction opposite to that indicated by the arrow A;

Fig. 2 is a view similar to Fig. 1, showing the position of the parts after force has been applied in the direction indicated by the arrow A;

Fig, 3 is a front elevational view of the switch shown in Fig. l, as viewed from the right of that ligure with the parts in the position shown in Fig. 2;

Fig. 4 is a side elevational view of a switch of the momentary type;

Fig. 5 is a modied form of a switch of the momentary type, showing the position of the parts after force has been applied in the direction indicated by the arrow F;

Fig. 6 is an enlarged cross sectional view on the line 6-6 of Fig. 3 with the parts in the position shown in Fig. 1;

Fig. 7 is a View similar to Fig. 6, showing the position of the parts when the actuating member is in its critical position;

Fig. 8 is a View similar to Figs. 6 and 7, showing the position of the parts when the actuating member is moved beyond its critical position;

Fig. 9 is a plan View showing a modied form of my improved switch, with parts broken away to show underlying structure;

Fig. 10 is a cross sectional view on the line l--IB of Fig. 9;

Fig. 11 is a detail view, showing means for placing tension upon the actuating member;

Fig. 12 is a perspective view of the switch shown in Figs. 9, 10 and 11 with the spring removed;

Fig. 13 is a perspective View on a slightly reduced scale of the spring shown in Figs. 9, 10 and 11;

Fig. 14 is a fragmentary cross sectional View of a yfurther modification of my improved switch;

Fig. 15 is a side elevational view of another modification of my improved switch, showing electrical means for actuating it;

Fig. 16 is an end view of the switch shown in Fig. 15;

Fig. 1'7 is an elevational view, partly in section of another modification of my improved switch, showing electrical means for actuating the switch;

Fig. 18 is a detail view of a portion of the switch shown in Fig. 17;

Fig. 19 is a plan view of another modification of my switch, showing means for thermostatically actuating the switch;

Fig. 20 is a side elevational view of the thermostat shown in Fig. 19 as viewed from a plane on the line 28-20 of Fig. 19; and

Fig. 2l is an enlarged cross sectional view on the line 2 I-2I of Fig. 20, as viewed in the direction of the arrows.

While my improved snap acting device may be constructed in various ways and be utilized for any suitable purpose, and I do not desire to be limited in this respect, for purposes of illustration, it is shown as constituting part of an electrical switch. As shown, the switch includes a member r arm I to be actuated having a free end provided with a tongue 2 and abutments or shoulders 2a and 2b adjacent tongue or projection 2 and an actuating member or lever 3 having a free end portion provided with a handle, 4 a tongue or projection and abutments or shoulders 5a and 5b adjacent said tongue or projection 5. As shown, tongue 2 and shoulders 2a and 2b are faced toward tongue 5 and shoulders 5a and 5b when the device is in its critical position and actuating lever 3 is provided with an opening 3a through which arm I to be actuated may be moved.

While the member to be actuated and the actuating member may be formed integrally or supported in any desirable manner, as shown in Figs. 1 to 3 of the drawings, both members are made of flexible material and are arranged with the stationary end of the actuating member adjacent to the stationary end of the member to be actuated, these adjacent ends being secured together by a suitable base structure designated generally by the numeral 6. When the parts are made separately, it is not essential that the member to be actuated be made of flexible material as it may be pivotally or hingedly supported by the base structure.

A suitable arcuate-shape spring 'l is operatively associated with the actuating member or lever and the member or arm to be actuated in such a manner that the spring rocks upon the abutments or shoulders provided upon or adjacent to the free ends of the members during movement of the actuating member. To provide this effecty it is essential that one portion of the spring shall bear upon the abutment on one member and another portion shall bear upon the abutment of the other member and that intertting parts be provided to secure the spring to the members which are loose enough when the spring is in its critical position to permit limited rocking movement of the spring in either direction from its neutral or critical position upon its abutments and which is capable when the actuating member is moved beyond its critical position of exerting opposite forces upon the actuating member and the member to be actuated as indicated by the force lines B and C. In the preferred form of my invention the spring I when placed under compression between the shoulders or abutments as shown, is also formed of stronger material than arm I and consequently the horizontal component of force B as shown in Fig. 1 bends the free end of arm I to the left, forming a curvilinear portion as indicated by the numeral la.

While the spring may be preformed, if desired, and may be associated with the actuating member and the member to be actuated in various ways, it preferably consists, as illustrated, of a thin at piece of resilient metal of spring temper, such as steel, beryllium copper, brass, bronze or the like which is cut to the desired length, and, as shown, may be provided with apertures spaced a short distance from its opposite ends which loosely receive tongues 2 and 5 when the spring is compressed into substantially the shape of a half circle with the parts of the spring adjacent to each tongue resting upon abutments 2a and 2b and 5a and 5b, respectively. Springs of the same length and sensitivity may therefore be readily prepared in a commercial manner so that switches or other devices in which they are employed may be duplicated without providing adjustments for variations in the springs.

As shown in the drawings and more particularly in Figs. l and 6, spring I maintains the actuating lever and arm I in spaced misaligned relation and when the parts are in this position, one portion of spring 'I engages the inner edge 3a of the abutments 5a and 5b of actuating lever 3 and a second portion of the spring engages the inner edge Ib of the abutments 2a and 2b on the arm I and when actuating lever 3 is moved by handle or actuator 4 in the direction indicated by arrow A, tongue 5 and abutments 5a and 5b of actuating member 3 engages spring I and moves it with a rocking action upon abutments 2a and 2b and abutments 5c and 5b until the actuating member reaches a point at which the apertures 'Ic and 'Id in spring are substantially in alinement with the free end of arm I and the ends 'la and Ib of spring 1 are substantially at right angles thereto. At this point actuating member 3 is in its critical or neutral position and tongues 2 and 5 t loosely in apertures 'Fc and ld. Upon further movement of actuating member 3 in the same direction, as illustrated in Fig. 8, a third portion of spring 'i' engages edge 3b of the abutments or shoulders 5a and 5b and a fourth portion of the spring engages the outer edge Ic of the abutments or shoulders on arm I and throws lever 3 in the same direction it has been actuated and arm I in the opposite direction with a snap motion. As portion Ia of spring I is curved, it will also be apparent that when the force of spring 'I is reversed, member or arm I will be thrown with a whip-like action. It will also be noted that after the flat spring is compressed into shape for assembly, the compression of the spring during actuation is substantially negligible and consequently the spring will retain its sensitivity.

It will be apparent that because of the action imparted to the spring during actuation and because of the thrust action of the entire width of the spring against the member to be actuated after the actuating member has passed its critical position, the wear upon the spring is small, and it will therefore have a long life in service. The

spring may therefore be made from comparatively thin strips of metal which increases its sensitivity.

The movable parts are now in the position shown in Fig. 2 of the drawings and the horizontal component of the force C of the spring bends the portion Ia of arm I to the right as shown in Fig. 2. In a like manner when operating lever is moved in the opposite direction as indicated by the arrow D, spring 1 is rocked upon the abutments or shoulders on arm I and actuating lever 3 and when the actuating lever passes its critical position, arm I is thrown in the oppo site direction with a whip-like action and lever 3 is thrown in the same direction as during actuation.

In the switch shown in Figs. l to 3, inclusive, the exible member or arm I which is formed of a suitable electrically conductive metal, such as copper or brass, is provided with a contact 8 on one face thereof below its free end portion which is adapted to engage a contact 9 on the inner face of an arm IS secured to the base structure E when the movable parts are in the position shown in Fig. l. The iiexible member I is also provided with a contact II on its opposite face below its free end portion which is adapted to engage a contact I2 on the inner face of an arm I3 secured to the base structure 6 when the parts are in the position shown in Fig. 2 of the drawings, Arms I0 and I3 are formed of electrically conductive metal, or if a single-throw switch is desired, either the arm le or I3 may be utilized as a stop.

While the base structure 6 may be of any suitable form for securing the stationary ends of arms I0 and I3 and the stationary ends of members I and 3 in place and maintai ing arms I0 and I3 in spaced electrically insulated relation, as shown the parte are held together by means of bolts I4 which pass through apertures in the adjacent ends of the arms and members and through insulating strips I5, such as iiber or molded material, interposed between the heads of bolts I4 and arm I3, between arms Ill and I3, respectively, and members I and 3 and between arm Il? and nuts IS by means of which the bolts are held in place. The metallic members are also insulated from the bolts by any suitable means, such as tubes lila, To provide terminals II, I8 and I9, a portion of arm Ill, actuating lever h 3 and arm I3 extend beyond the base structure. While in the structure shown actuating lever 3 is extended to form terminal I8 because it is formed of thicker metal than arm I and the adjacent ends of arm I and lever 3 are held together by the bolts in electrical Contact with each other, if desired, terminal le may be formed upon arm I.

In the form of switch shown in Figs. 1 to 3, inclusive, it will be noted that when the flat spring 'I is assembled in place, it is compressed to a considerable extent. It therefore requires only a short movement of lever 3 in the direction indicated by arrow A as shown in Fig. 1 to actuate the device after it is moved to its critical or neutral position, Upon movement of lever 3 past its critical or neutral position in the direction indicated by arrow A, spring 'I throws member I with a snap action in the opposite direction causing contact II to engage contact I2 as shown in Fig. 2 and in view of the whip-like action, positive engagement of Contact II with contact I2 is assured. Since the horizontal component of force C of spring 'I bends the upper portion of arm Ia to the right as shown in Fig. 2, it will also be seen that leverage means are provided for maintaining contact I I firmly in engagement with contact I2. In a like manner when force is applied in the direction indicated by arrow D, spring "I is rocked upon its shoulders or abutments and contact B is thrown with a whip-like action into engagement with contact Q and is maintained in engagement therewith by the horizontal com ponent of force B of the spring.

As contact 8 does not leave contact 9 until actuating member 3 passes its critical position and on the return movement of the actuating lever contact II does not leave contact I2 until actuating lever passes its critical position, a quick make and break of the contacts are provided which minimizes volatilization of the contacts and in View of the positive engagements of the contacts and the leverage means for maintaining them in engagement when made, it is apparent that positive engagement of the contacts will occur even though thcactuating member 3 is oscillated in opposite directions at comparatively high speeds. It will. also be noted that when the contacts are made, it is not necessary for current to flow through spring 'l which may therefore be made of a metal, such as steel, which has less electrical conductivity than member I and arms I and I3.

The snap acting devices shown in Figs. 4 and 5 are somewhat similar to that shown in Figs. 1 to 3 and spring 'I is operatively associated with arm I and lever 3 to provide limited rocking movement of the spring in either direction from acritical position upon the abutments or shoulders formed upon the free ends of these members, as shown in Figs. 6, '7 and 8. The parts have accordingly been designated by the same numerals. The de- 'vices are so constructed and arranged, however,

that when the force upon actuating member 3 is released, the parts return to their original position. This may be erlected in various ways, such as by arranging the xed end of lever 3 in cantilever fashion and adjusting its fixed end to bias its free end away from the member to be actuated as shown in Fig. l0 to be subsequently described, by forming lever 3 of flexible material and spacing it from the member to be actuated, or by placing the fixed end of a iiexible actuating lever which is stronger than the spring adjacent to the fixed end of the arm to be actuated and biasing it away from the arm,

As shown in Fig. 4, all parts of actuating lever 3 are spaced to the right of arm I and if desired actuating lever 3 may also be constructed of stronger material than spring Spring 'I in turn is formed of stronger material than arm I and consequently when the parts are in the position shown in Fig. e, the horizontal component of the force of spring 'I bends the portion Ia of arm I to the left and the leverag-e of this force acting through portion la maintains contact 8 firmly in engagement with contact 3. It also enables arm I to be thrown with a whip-likeaction to cause engagement of contact II with contact I2 when force is exerted upon lever 3 in the direction indicated by arow E and to be returned with a whiplike action when the force is removed. In the switch shown in Fig. e it is of course necessary to have terminal IS on arm I.

The switch shown in Fig. 5 is similar to that shown in Fig. i with the exception that actuating lever 3 is arranged adjacent to the arm I and is made of stronger material than spring 'I and is biased to the right. In this modication arm I is also formed of stronger material than spring I when spring 1 is under compression and although arm l is thrown with a snap action, a whip-like action is not obtained. While a switch of this type is not as sensitive as that shown in Figs. 1 to 4, it possesses all of the other advantages specified and is satisfactory for purpose in which extreme sensitivity is not required. The switch shown in Fig. is of the momentary type and when force is exerted upon lever 3 in the direction indicated by arrow F contact H will be thrown with a snap action into engagement with contact l2 and upon release of the force the parts will return with a snap action to their original position.

While as previously stated either the member i or the member 3 may be utilized as the actuating member, it is preferable to utilize member 3 as the actuating member and member l as the member to be actuated because greater leverage is provided. In the structure shown in Figs. 1 to 4, inclusive, it is also preferable to utilize member 3 as the actuating member and arm I as the member to be actuated because in such case a Whiplike action is obtained which assures positive movement of the member to be actuated even though the actuating member is oscillated at high speed.

Figs. 9 to 13, inclusive, of the drawings disclose a modication of my improved snap acting device which in addition to including all the advantages of the modifications shown in Figs. 1 to 5, inclusive, is provided with improvements which render it more eifective in service.

While the device shown in Figs. 9 to 14 may be made in various ways and the actuating member or lever may be formed separately from the member to be actuated, as shown in the drawings, the actuating member and the member to be actuated are formed as a single stamping from a sheet of flexible metal. When the members are formed separately, however, it is not essential that the actuating member be formed of flexible material. As shown more particularly in Fig. l2, member or lever 25 extends longitudinally in an opening in the arm or member to be actuated and is provided with a shoulder or abutment 26 having tongues or projections 21 and 21a on opposite sides thereof and in a like manner the member or arm 29 to be actuated is provided with a shoulder or abutments 30 facing the abutment 26 when the parts are in their crtical position and has tongues or projections 3| and 3 la at the opposite sides thereof.

While the spring may be preformed if desired, a normally at spring 32 is preferred as shown in Fig. 13 which is compressed into the form of an arc and is interposed between members 25 and 29 with one portion of the spring bearing upon abutment 30 and another portion bearing on abutment 26. Means are also provided for operatively connecting to spring the actuating lever and the member or arm to be actuated in such a manner that the spring is free to rock upon abutments 26 and 30 to a limited extent in either direction from the critical position, and while a tongue which lits loosely through apertures in the spring may be provided, as shown in Figs. 6, 7 and 8, for convenience of assembly, notches 33 and 34 are cut in the opposite sides of the spring adjacent one end thereof which loosely receive tongues 21 and 21a and notches 35 and 36 are cut on opposite sides adjacent the opposite end of the spring which loosely receive tongues or projections 3l and 3la when the spring is compressed and its opposite ends bear upon abutments 26 and 30. When my improved snap acting device is asucA sembled as shown in Figs. 9 and l0 of the drawing, it will be apparent that movement of the actuating lever in one direction will move the arm to be actuated in the opposite direction and that in a like manner, movement of the member to be actuated in one direction will move the actuating member in the opposite direction.

While the means for supporting my improved device will of course be dependent upon the function it is desired to perform and the particular apparatus with which it is associated, for purposes of illustration, an assembly is shown in Figs. 9 and 10 comprising a base 31 having a downwardly inclined portion 3S and a cover 39 having an aperture which receives a freely slidable plunger 4l! for moving the actuating member.

As in the structure shown in Fig. 5, the free end of the actuating lever 25 is biased from the plane of the member to be actuated and carries the freely slidable plunger. For this purpose the end 4| of the stamping shown in Fig. l2 is provided with an arcuate portion 42 having a central aperture 42d and when the device is assembled, one end of the arcuate portion fits in a groove 43 formed in the base and the other end bears upon the upper part of the inclined surface 38 and a bolt or screw 44 having a head 44a extends through aperture 42a and is threaded into a sleeve 45 formed in the base. It will be apparent that by threading the screw downwardly, the head of the screw will engage the arcuate portion of the actuating member and will bias the free end of the actuating lever up Wardly from the member or arm to be actuated as clearly shown in dotted lines in Fig. ll and this biasing eiect will be proportional to the pressure exerted by the screw head upon the arcuate portion. As shown in Figs. l0 and l1, the member or arm 29 to be actuated will therefore normally be held in its lowermost position by the spring and the amount of force required to actuate member 25 by plunger 49 may be accurately regulated. For instance, after the device of a particular type has been set by the screw to determine the pressure required to actuate the device, the head of the screw may be soldered to the arcuate portion of the stamping to prevent further turning of the screw.

The distance or" travel of plunger li to actuate the device is dependent upon three factors; namely, the pretravel of the plunger before it starts to actuate the device, its travel during actuation, and its post travel after actuation. Means are provided to regulate or limit each of these three factors to provide a device which may vary in sensitivity or which is extremely sensitive in operation.

To regulate the pretravel, a suitable stop may be provided, such as the downwardly extending lug 46, as shown in Fig. 14. I prefer, however, to utilize adjustable means, such as a screw or threaded bolt 41 provided with a head 4G, the shank of which extends through an aperture 49 in the actuating member and is threaded into the base 31 With the head of the screw or bolt extending at least a suiiicient distance above .inclined surface 38 to cause spring 32 to hold member 29 in its lowerrnost position. When the head 48 of the screw is in its lowerrnost position, no pretravel of the plunger is required before it starts to actuate the device. When the head of the screw is raised from its lowermost position, the pretravel distance of the plunger varies in proportion to the distance the screw is raised.

To limit the movement of the plunger while at the same time assuring positive actuation of the device after its pretravel, spring 32 when placed under compression is preferably constructed of stronger material than lever 25 and after tension has been placed upon lever 25 and the device is in the position shown in Fig. 10, the upward component of the force of the spring, which force is designated by the arrow G as shown in Fig. 11, bends the end of lever 25 extending beyond screw head 128 upwardly providing a curve at the end of the lever which is substantially in the form of a parabola. The upper component of the force of spring 32 is relatively small but it is very effective because it is exerted at the extreme end of the lever and consequently a comparatively small movement of plunger 4B through its actuating travel throws lever 25 with a whip-like movement through a comparatively large arc which assures positive and rapid movement of the arm to be actuated. When the device is actuated the force exerted by spring 32 is reversed. The upward component of this force, however, is comparatively small, and consequently when the force upon plunger 45 is released, lever 25 returns to its normal position carrying the plunger with it.

The travel of plunger 451 is also determined by the distance it is set from screw 411, less travel being required when it is nearer screw 44 than screw 41. More force, however', is required to operate plunger 45 when it is set close to screw 44 and the distance of post travel is limited. It is therefore preferably arranged to exert its force substantially midway between screws 44 and 41 at which surface 38 is inclined sufficiently from lever 25 to provide a suicient travel of plunger 40 to actuate the device.

The post travel of plunger 49 is of course limited by surface 38 which is inclined downwardly beyond the plunger to provide space for a comparatively large movement of lever 25 at its free end but which is in sufciently close proximity to the lever when the lever is in its lowermost position, as shown in dotted lines in Fig. l0, to prevent actuation of the lever beyond the elastic limit of the metal of which it is composed. In commercial practice, it is of course desirable to provide some pretravel and some post travel and consequently during normal operation, screw 41 is set and surface 38 is inclined to provide suicient pretravel and post travel to assure positive actuation of the device.

The plunger 40 may be of any desirable type, such as shown in Fig. 10. In the event, however, that actuating means is utilized in which there is danger of moving the plunger too far, a plunger 5U of the type shown in Fig. 14 may be utilized in which resilient means, such as a spring 5I, is interposed between the head 51a of the plunger and a shoulder 52 and the base of the plunger is provided with a bore to receive stem 54 after the base 54a of the plunger forces lever 25 into engagement with inclined surface 38. Stem 54 is provided with a flange 55 to limit the upward movement of head 51a. The plunger may of course be actuated by any convenient means, such as a cam, thermostatic rod or the like.

When the snap acting device is utilized in switches, as illustrated in Figs. 9 and 10 of the drawing, the base 31, cover' 39 yand the base 54a of the plunger are formed of a suitable insulating material, such as a phenolic condensation product. In such case sleeve 45 is extended to receive a terminal screw 55 and suitable contacts I56 and 51 are arranged opposite to contacts 58 and 59 on the opposite sides of the member to be actuated. It will of course be understood that if the arm 29 to be actuated is separate from lever 25, terminal screw 55 must be electrically connected to that member. The contact 58 is electrically connected to a suitable electrically conductive arm which is in electrical contact with bushing 5l provided with a terminal screw 52 and in a like manner contact 51 is connected through a suitable electrically conductive arm 53 to a bushing 54 provided with a, suitable terminal screw, not shown. It will of course be understood that if it is desired to make and break only one circuit, contact 56 may be omitted and arm 5G may be utilized as a stop.

While a certain amount of a whip-like action of the actuating arm is obtained in the modifications shown in Figs. 1 to 4, it is apparent that this action is greatly increased in the structure shown in Figs. 9, 10 and 11. This is due to the fact that tension is placed upon lever 25 which biases its free end upwardly, the end of lever 25 extending beyond screw head i8 is curved upwardly by the force of spring 32, and the :actuation force is applied in proximity to the fixed end oi the lever. When the force of plunger 40 upon lever 25 is released, however, the arm quickly returns to its original position and carries plunger 49 with it. The plunger may therefore be intermittently operated at high speed to make and break circuits.

By actual tests, I have found that a distinct combination exists between the means for producing the whip-like action of the actuating lever and the spring which rocks upon abutments formed upon the extreme end of the lever and adjacent to the free end of the arm to be actuated which enables results to be produced which are in no manner approximated by any other snap acting device which has heretofore been devised. For instance, in actual tests it has been demonstrated that my improved snap acting device may be operated to positively make and break circuits at rates ranging from 400 to 3200 times or more per minute which compares favorably with results achieved by gas-filled tubes of the thermionic type that are available only at high prices.

The snap acting device disclosed in `Figs. 9 t0 13 may be readily adjusted so that actuating lever 25 will not return to its original position after being actuated as illustrated in Fig. 14 of the drawing. For this purpose, screw 44 is adjusted to release the tension on actuating lever 25, an additional plunger 6d is provided to move the actuating member upwardly :after it has been displaced by plunger 45, and a stop 45 is provided to limit the upward movement of the actuating lever. In other respects, the snap acting device disclosed in Fig. 14 is similar to that shown in Figs. 9 to 13.

The switch illustrated in Figs. l5 and 16 is somewhat similar to that shown in Figs. 9 to 15 and includes an actuating member or lever 55 which is normally biased upwardly from an arm 01 member 5i to be actuated. As shown, the arm and lever are hxed at one end :adjacent to each other upon a support 52 extending upwardly from a base 63. Base 53 is formed of a suitable insulating material and is provided with an insert to which the lower portion of the support is attached by a terminal screw 64 which extends 11 through a flange of the support and is threaded into the insert.

A spring 65, preferably formed of flat material and compressed into an arcuate shape, bears upon shoulders or abutments of the actuating lever :and the arm or member to be actuated and is loosely connected to said lever and arm when the parts are in a critical position in the manner shown in Figs. 9 to 13 and more particularly described in connection with Figs. 12 and 13 to provide a rocking action of the spring upon the supports.

To limit the upward movement of lever 60, a stop 66 is provided which is `adapted to be engaged by an upwardly inclined head 61, the shank of which extends through openings in lever 60 and arm I, such as those shown in lever 25 and arm 29 of Fig. 13, and is provided with a base 68 formed of a suitable magnetizable material, such :as iron. As illustrated when spring 65 is placed under compression, it is stronger than lever `60 and consequently the upward component of the force of the spring bends the end of lever upwardly against the inclined surface of head l61 which serves as a stop.

For actuating the switch, a coil or solenoid 69 is iixed to base 63 by any suitable means, such as a screw 10, and when the coil is energized, it attracts magnetizable base 68 and head 61 engaging lever 60, throws lever 60 downwardly with a whip-like action. As shown more particularly in Fig. 16 of the drawing, arm 6| is provided with contacts 1| and 12 on opposite faces ywhich are adapted to selectively engage contact 13 formed upon :a support 14 secured to the base by a terminal screw 15 and a contact 16 formed upon support 11 which is also secured to the base by a terminal screw 18. If it is desired, however, to make or break only one circuit, one of the supports may be utilized as a stop.

Figs. 17 and 18 disclose another modification of my improved switch which is somewhat similar to that shown in Fig. 4 and similar parts have been designated by the same numerals. Instead of providing the actuating member or lever with an opening as shown in Fig. 4, it is iiXed to the base structure by the bolts I4 and its free end serves as a support for a magnetizable base 80 having a stem 8| secured to iiexible lever 3 by suitable means, such as a nut 82. The

free end of lever 3 also serves to support an arm 83 which is insulated from base 80 by a studded washer 84 and an insulated spacer 85 is interposed between lever 3, the stud of washer 84 and arm 83 and serves to maintain arm 83 in proper relation to arm when the parts are in the position shown in Fig. 17. As illustrated in Figs. 6, '1 and 8 a flat spring is curved into an. arcuate shape and is compressed between and rocks upon shoulders or abutments formed upon the free end of arms I and 83 and is loosely interconnected with tongues or projections 2 and formed upon arms and 83, respectively, when the parts are in their critical position to permit limited rocking movement of the spring upon the abutments in either direction from the critical or neutral position. As in Fig. 4 it will be noted that spring 1 when compressed is stronger than arm I and consequently the downward component of the force of the spring bends the portion la of arm I which extends beyond contact I2 downwardly in a curvilinear shape as shown in Fig. 1'7 so that when lever 3 is moved toward arm I3, arm I is thrown with a whiplike action in the opposite direction.

To actuate the device an arm 86 insulatingly connected to the base structure 6 supports a coil or solenoid 81 which when energized attracts magnetizable base to flex the free end of lever 3 and as arm 33 moves past its critical position, spring 1 throws arm I with a whip-like action in the opposite direction and spring 1 in its new position exerts a force which bends the portion Ia of arm I upwardly to provide a whiplike action of arm I in the opposite direction when coil 81 is deenergized and lever 3 returns to its normal position.

In Figs. 19, 20 and 21 of the drawing, thermostatic means are shown for operating my improved device. As illustrated, a bimetallic actuating lever is provided with a coil actuator 9| at one end which is held in the groove of a terminal post 9Ia by any suitable means, such as a screw 92, and has a free end which extend beyond a pair of spaced contacts 94 and 95 supported by a movable arm 96 pivotally mounted upon the base by any suitable means, such as a screw 91. As illustrated, the bimetallic lever is provided with an opening 98 forming an end portion 99 from which a projection or tongue |00 extends into the opening and which end portion provides shoulders or abutments adjacent the tongue. The arm or member IOI to be actuated is also formed of a exible bimetallic member, one end of which is riveted or otherwise secured to bimetallic lever 90 adjacent the opposite edge of the opening, as indicated by numeral |02, and is provided with contacts |03 and |04 on opposite faces, one of which is adapted to engage contact 94 and the other of which is adapted to engage contact when the arm is thrown in opposite directions from its critical position. The free end of arm IOI extends beyond contacts 94 and 95 and has a tongue or equivalent projection |05 thereon and shoulders or abutments adjacent the tongue |05.

To increase the sensitivity of my improved device, the component parts of the bimetallic lever and bimetallic arm are arranged so that variation in temperature cause movement of the lever in one direction and movement of the arm in the opposite direction. For this purpose, see Fig. 21, strip |06 of bimetallic lever 90 is formed of a metal having the same or substantially the same coe'icient of expansion as the strip |01 of arm IOI and in a like manner strip |08 of the bimetallic lever is formed of metal having the same or substantially the same coefficient of expansion as strip |09 of the arm. The coefficients of expansion of strips |06 and |01, however, vary decidedly from the coefficients of expansion of strips |08 and |09 so that upon variation of the temperature lever 90 moves in one direction whereas arm I0| moves or tends to move in the opposite direction.

To provide a whip-like movement of arm |0I upon variation of temperature, an arcuate shaped spring I|0, which is formed preferably by bending a normally flat strip into the desired shape,

is provided with an aperture at its central portion and apertures adjacent its opposite ends, the aperture at the central portion being adapted to loosely receive tongue |00 and to bear on the shoulders or abutments on the end portion 99 adjacent thereto and the apertures at the opposite ends being adapted to loosely receive tongue |05 and to bear upon the shoulders or abutments on arm |0| adjacent thereto when the parts are 75 in their neutral or critical position. It will be noted that the spring when compressed is stronger than arm IDI and consequently when contact |03 engages contact 94, or when contact |04 engages contact 95, the portion of the arm extending beyond contact 94 or contact 95 is bent into a curvilinear shape and this curvilinear shape is accentuated by utilizing a spring of the type shown which has subsequently twice the effect of the spring shown in the other modifications.

With the parts in the position shown in Fig. 19 and assuming that an increase of temperature will cause bimetallic lever to move toward the left, causing a rocking movement of the spring upon its supports, bimetallic arm IOI will have the tendency to move toward the right but contact |03 is prevented from leaving contact 94 by the force of spring I I which is stronger than the flexible arm. When bimetallic lever 90 reaches its critical position, however, the direction of the force exerted by spring IID is changed and bimetallic arm I9I is thrown with a whip-like action in the opposite direction and the force of the spring is accentuated by the inherent force exerted by the bimetallic components of the arm. Upon cooling of the bimetallic members, a similai` but opposite movement of the parts occurs as will be readily understood.

Means are also provided for varying the position of contacts 94 and 95 and thus vary the force required to move the free end of bimetallic lever to its critical position. For this purpose the free end of arm 95 is provided with a recess III to receive a cam II2 which is pivoted to the base and is provided with an operating handle I|3. As shown, appropriate conductors II4 and II5 lead from contacts 94 and 95 to terminal screws I I6 and I I'I. When it is desired to make or break only one circuit, either conductor II4 or II5 may be omitted and one of the contacts may be utilized as a stop.

In Figs. 19 to 2'1 of the drawings, it will be noted that when cam I I2 is set in a denite position by means of handle II3, contacts 94 and 95 are rigid and stationary and remain in this stationary position during actuation of the switch by means of the thermostatic coil actuator 9|. As illustrated in the drawings, contact ID3 on arm I0! engages stationary contact 94 and a portion of arm IOI extends beyond contact ID3 and is provided with an abutment at its free end having spaced inner and outer edges, the inner edge of which is engaged by spring |I0 which bends the free end of arm |0I to the left as shown in Fig, 19 of the drawing, forcing contact |03 rmly into engagement with contact 94 and when the bimetallic coil actuator 9| which is arranged adjacent one end of actuating lever 90 is subjected to variation in temperature, such as by means of heat, it moves the free end 99 of lever 90 toward the left against the force of spring IID, another portion of which spring engages the inner edge of the abutment adjacent the free end of lever 9D, thereby rocking spring I I0 upon the abutments adjacent the free end 99 of lever 9D and upon the abutments on the free end of arm II until the free end 99 of lever 9D reaches a critical position in which lever 9D and arm IOI are substantially in alignment with each other and as lever 90 passes through its critical position, spring ||9 is rocked to such a position that a third portion of the spring engages the outer edge of the abutment on arm IDI and a fourth portion of spring IID engages the outer edge of the abutment adjacent the free end of' lever 90 and throws arm IDI and lever 9D in opposite directions with a snap motion, causing contact |04 on the opposite side of arm IDI to engage stationary contact 95.

The switch illustrated in Figs. 19 to 21 is also designed to be actuated by means of handle II3 irrespective of the temperature of the room in which it is placed. Assuming, for instance that the parts of the switch are in the position shown in Fig. 19, it will be noted that contact |03 on arm IDI engages electrode 94 which may act as a contact or as a stop and a portion of arm IDI extends beyond the stationary contact or stop 94 and spring I I0, one portion of which engages the inner edge of the abutment on arm IDI and a second portion of which engages the inner edge of the abutment adjacent the free end of bimetallic arm 90, exerts suicient force upon the free end of arm IOI to hold contact ID3 iirrnly in engagement with contact or stop 94 and bends the free end of arm IOI to the left. In this case arm |0I becomes the actuating lever and bimetallic arm the member or arm to be actuated, and when handle II3 is moved toward the right it rotates cam |I2 about its pivot causing electrode 94 to engage arm I 0I intermediate its ends and move it to the right in opposition to spring IIO, thereby rocking spring II9 on the abutments adjacent the free end of bimetallic arm 90 and upon the free end of arm IDI, until arm IDI reaches a critical position in which arm IDI and bimetallic arm 90 are substantially in alignment with each other, at which time a third portion of spring IIIl engages the outer edge of the abutment on arm IDI and a fourth portion of the spring engages the outer edge of the abutment on bimetallic arm 99 and throws arm IDI in the same direction and bimetallic arm 90 in the opposite direction with a snap motion, thereby moving contact |04 into engagement with contact 95. When arm IDI is in a position to cause contact |04 to engage contact or electrode 95, it will also be apparent that by moving handle II3 to the left, cam II2 will engage the left hand prong of arm 95, causing electrode 95 to engage arm IOI intermediate its ends, thereby moving arm IDI toward its critical position against the force of spring I I0 which rocks upon the abutments on the free end of arm IDI and upon the abutments adjacent the free end 99 of bimetallic arm 9D until the parts pass through their critical position at which time a third portion of spring III] engages the opposite edges of the abutments on arm IilI and a fourth portion of the spring engages the opposite edges of the abutments on bimetallic arm 90 and throws arm IDI with a whip-like action to the left and bimetallic arm 9D in the opposite direction, causing contact |93 on arm I9I to engage electrode or Contact 94 and spring IIS exerts a force on the free end of arm II holding contact |03 firmly in engagement with electrode or contact 94.

What I claim is:

1. A snap acting device comprising a stop, an arm to be actuated provided with a free end portion, a flexible actuating lever having a xed end and a free end portion extending beyond said stop, spring means arranged between and being held under compression between the free end portions of said lever and arm for moving said arm with a snap action upon movement of said lever, means associated with the fixed end of said lever for biasing said lever away from said arm and into engagement with said stop, said spring being responsive to the movement of the lever into engagement with said stop for throwing the member to be actuated in the opposite direction with a snap action and said spring having suficient strength when held under compression to bend the portion of said lever extending beyond said stop in a curvilinear shape, an actuator arranged between said stop and the xed end of said lever for actuating said lever and for throwing its free end with a whip-like action to move said arm with a snap action in the opposite direction, and said lever being biased sui'iciently to return to its original position when the force upon said lever is released.

2. A snap acting device comprising a stop, an arm to be actuated provided with a free end portion, a flexible actuating lever having a fixed end and a free end portion extending beyond said stop, spring means arranged between and being held under compression between the free end portions of said lever and said arm for moving said arm with a snap motion upon movement of said lever, means associated with the fixed end portion of said lever for biasing said lever away from said arm and into engagement with said stop, which biasing means is adjustable to regulate the force required to move said lever, said spring means being responsive to the movement of the lever into engagement with said stop for throwing said arm in the opposite direction with a snap motion and said spring means having suiiicient strength when held under compression to bend the portion of said lever extending beyond said stop in a curvilinear shape, an actuator arranged between said stop and the fixed end of said lever for actuating said lever and for throwing its free end with a whip-like action to move said arm with a snap action in the opposite direction, and said lever being biased sumciently to return to its original position when the force upon said actuator is release 3. A snap acting device comprising a stop, a ilexible actuating lever having a fixed end and a free end portion extending beyond said stop which is provided with an abutment, an arm to be actuated having one end mounted in proximity to the i'lxed end of said lever and a free end portion provided with an abutment, an arcuateshaped spring having a portion bearing on the abutment on said arm which is loosely connected to said arm and a portion bearing on the abutment on said lever which is loosely connected to the lever to permit rocking movement of said spring on said abutments in either direction from a position in which said arm and lever are in substantial alignment with each other, means associated with the xed end of said lever for biasing it into engagement with said stop, said spring being held unde compression between said abutments and having suilicient force to maintain said arm in spaced misaligned relation to said lever and to iiex the portion of the lever which extends beyond said stop, and means for applying force to said lever adjacent its fixed end for throwing said lever with a whip-like action and rocking said spring upon said abutments to a position in which it forces said arm in the opposite direction with a snap motion and the bias vimparted to said lever being sufficient to cause it to return to its original position when said force is released.

4. A snap acting device comprising a metal actuating member having a mounted end and a free end portion, a flexible member to be actuated having a free end portion extending in the same general direction as the actuating member and i6 at least one of said members being provided with an abutment having spaced inner and outer edges, spring means disposed between the free end portions of said members with one portion of said spring means engaging the inner edge of said abutment and being rockable on said abutment during movement of the actuating member relative to the member to be actuated and said spring means having suiiicient force when held under compression to maintain the free end portion of said members in spaced misaligned relation, an actuator applied to said actuating member adjacent its mounted end for moving the free end portion of said actuating member against the force of said spring means, and said spring means being movable with the actuating member during movement of said actuating member to rock said spring means on said abutment to gradually change the direction of the force of said spring means until the actuating member is substantially in alignment with the member to be actuated, and said spring means being also movable with the actuating member when the actuating member is moved in the same direction beyond alignment with the member to be actuated to rock said spring means upon said abutment to a second position in which a second portion of the spring means engages the opposite edge of said abutment to provide opposite movement of said members relative to each other.

5. A snap acting device comprising a metal actuating member having a mounted end and a free end portion provided with an abutment including a tongue, a flexible arm to be actuated having a `free end portion extending in the same general direction as the actuating member and being provided with an abutment including a tongue and each of said abutments having spaced inner and outer edges, spring means disposed between and being held under compression between said abutments with one portion of said spring means engaging the inner edge of the abutment on said actuating member and being held in operative association therewith by means of the tongue on the actuating member and another portion engaging the inner edge of the abutment on said aan and being held in operative association therewith by means of the tongue on said arm, said spring means being rockable on said abutments during movement of said actuating member relative to said arm and said spring means having sufficient force to maintain the free end portions of said member and said arm in spaced misaligned relation, an actuator applied to said actuating member adjacent its mounted end for moving the free end portion of said actuating member against the force of said spring means and said spring means being movable with the actuating member during movement of said actuating member to rock said spring means on said abutments to gradually change the direction of the force of said spring means until the -actuating member is substantially in alignment withv the member to be actuated and said spring means being also movable with the actuating member when the actuating member is moved in the same direction beyond alignment with said arm to rock said spring means to a position in which a third portion oi" said spring means engages the outer edge of the abutment on the actuating member and a fourth portion of said spring means engages the outer edge of the abutment on said arm to provide opposite swinging move- 17 ment of said member and said arm relative to each other.

6. A snap acting device comprising a metal actuating member having a mounted end and a free end portion provided with an abutment, a flexible arm to be actuated having a free end portion provided with an abutment, and each of said abutments h-aving spaced inner and outer edges, an arcuate-shaped spring provided with spaced apertures, said spring having one portion engaging the inner edge of the abutment on said lever and another portion engaging the inner edge of the abutment on said arm, means for maintaining said spring in operative association with said actuating member and said arm including a projection on the actuating member extending loosely through one of said apertures in the spring and a projection on said arm extending loosely through the other aperture in said spring, said spring being held under compression between the inner edges of said abutments and having suiiicient force -to maintain the free end portions of said member and said arm in spaced misaligned relation, an actuator applied to said actuating member adjacent its mounted end for moving the free end portion of said actuating member against the force of said spring and said spring Ibeing movable with -the actuating member during movement of the actuating member to rock said spring on said abutments to gradually change the direction of the force of said spring until the actuating member is substantially in alignment with said arm and said spring being movable with the actuating member when the actuating member is moved in the same direction beyond alignment with said arm to rock said spring to a position in which a third portion of said spring engages the outer edge of the abutment on said actuating member and a fourth portion of said spring er1/'gages the outer edge of the abutment on said/arm to provide opposite swinging movement of said member and said arm relative to each other.

7. A snap acting switch comprising an actuating member having a mounted end and a free end portion, a stationary contact, a exible arm to be actuated having a free end portion extending beyond said contact, a contact carried by said arm which is movable into and from engagement with the stationary contact, spring means having one portion in engagement with the actuating member at its free end portion and a portion rockable on the free end portion of said arm and having suiiicient force to maintain the movable Contact in engagement with the stationary contact and to ilex that portion of the arm which extends beyond the stationary contact, an actuator applied to said actuating member adjacent its mounted end for moving the free end portion of said actuating member against the force of said spring means and said spring means being movable with the actuating member during movement of said actuating member to rock said spring means on the free end portion of said arm to gradually change the direction of the force of said spring means until the actuating member is in substantial alignment with said arm and said spring means being also movable with the actuating member when the actuating member is moved in the same direction beyond alignment with said arm to rock said spring means on said arm to a second position in which the force -of said spring means throws the arm in the opposite direction with a snap motion.

8. A snap acting device comprising a member to be actuated having a mounted end and a tree end portion, a flexible actuating member having a free end portion extending in the same general direction as the member -to be actuated and at least one of said members being provided with an abutment having spaced inner and outer edges, spring means disposed between the free end portions of said members with one portion of said spring means engaging the inner edge of Said abutment and being rockable on said abutment during movement of the actuating member relative to the member to be actuated and said spring means having sufficient force when held under compression to maintain the free end portions of said members in spaced misaligned relation, an actuator applied to the actuating member intermediate its ends for moving the free end portion of said actuating member against the [force of said spring means, and said spring means being movable with the actuating member during movement of said actuating member to rock said spring means on said abutment to gradually change the direction of the force of said spring means until the actuating member is substantially in alignment with the member to be actuated, and said spring means being also movable with the actuating member when the actuating member is moved in the same direction beyond alignment with the member to be actuated to rock said spring means upon said abutments to a second position in which a second portion of the spring means engages the opposite edge of said abutment to provide opposite movement of said members relative to each other.

9. A snap acting device comprising a member to be actuated having a mounted end and a free end portion, said member having an opening therein throughout a substantial portion of its length and being provided with an abutment incluging a tongue extending into one end of'said opening, a iiexible actuating lever of less length than said member having one end supported at a position remote from said tongue and a free end portion which is movable through said opening,"

spring means having one end engaging the free end portion of said lever and another portion rockable upon said abutment during movement of said lever relative to said arm and said spring means being loosely held in engagement with the abutment on the member to be actuated by the tongue on said member, an actuator applied to said lever intermediate its ends for moving said lever through said opening against the'force of said spring means until said lever reaches a critical position in which said lever is substantially in alignment with the member to be actuated, and the movement of said lever beyond its critical position being eiective in rocking said spring means upon said abutment to a second position in which the force of the spring means throws the member to be actuated with a snap motion in a direction opposite to the movement of said lever.

10. A snap acting device comprising a stop, a member to be actuated having a mounted end and a free end portion, a ilexible actuating lever extending in the same general direction as the member to be actuated, said lever having a mounted end and a free end portion extending beyond said stop, spring means having one portion rockable on the free end portion of the actuating lever and another portion rockable on the free end portion of the member to be actuated during movement of said actuating lever relative to said member, said spring means being held under compression between thefree end portions of said member and said lever and having suicient force when held under compression to maintain said lever in engagement with said stop and to flex the free end portion of said lever which extends beyond said stop, and an actuator for applying force to said lever intermediate its ends to move the free end portion of the lever against the force of said spring means to a critical position in which the free end portion of said lever is in substantial alignment with the free end portion of said arm and said spring means being also movable with said lever when the lever is movedbeyond its critical position to rock said spring means to a position in which the force of the spring means throws said arm in a direction opposite to the movement of said lever.

11. A snap acting device comprising a member to be actuated having a mounted end and a free end portion provided with an abutment, a exible actuating lever having a free end portion provided with an abutment which is spaced from the abutment on the member to be actuated and each of said abutments having inner and outer spaced edges, a spring having one portion engaging the inner edge of the abutment on the member to be actuated and another portion engaging the inner edge of the abutment on the actuating lever, said spring being provided with spaced openings and being rockable on said abutments during movement of said lever relative to the member to be actuated, means for maintaining said spring in operative association with said abutments including a projection extending from the abutment of themember to be actuated which is loosely received in one of the openings in said spring and a projection extending from the actuating lever which is loosely received in the other opening in said spring, said spring being held under compression between said abutments and having sufficient force to maintain the free end of said lever in spaced misaligned relation to the free end of said member, and an actuator applied to said lever intermediate its ends for moving said lever against the force of said spring to a critical position in which the free end portion of said lever is substantially in alignment with the free end portion of said member to rock said spring on said abutments and the movement of said lever beyond its critical position being effective in rocking said spring to a position in which a third portion of said spring engages the outer edge of the abutment on said lever and a fourth portion of said spring engages the outer edge of the abutment on the member to be actuated to throw said lever and said. member in opposite directions with a snap motion.

12. A snap acting device comprising a member to be actuated having a mounted end and a free end portion, said member having an opening therein throughout a substantial portion of its length and being provided with an abutment adjacent one end of the opening, a exible actuating lever of less length than said member having one end supported at a position remote from said abutment and a free end portion provided with an abutment which free end portion is movable through said opening, and each of said abutments being provided with inner and outer spaced edges, a spring having one portion engaging the inner edge of the abutment on said member and another portion engaging the inner edge of the abutment on said lever and said spring being provided with spaced openings and being rockable on said abutments during movement of said lever relative to said member, means for maintaining said spring in operative association with said abutments including a projection extending from the abutment of the member to be actuated which is loosely received in one of the openings in said spring and a projection extending from the actuating lever which is loosely received in the other opening in said spring, said spring being held under compression between said abutments and having sufficient force to maintain the free end of said lever in spaced misaligned relation to the free end of said member, and an actuator applied to said levergintermediate its ends for moving saidlever against e rce of said spring to a critical position in which the free end portion of said lever is substantially in alignment with the free end portion of said member to rock said spring on said abutments and the movement of said lever beyond its critical position being elective in rocking said spring to a position in which a third portion of said spring engages the outer edge of the abutment on said lever and a fourth portion of said spring engages the outer edge of the abutment on the member to be actuated to throw said lever and said member in opposite directions with a snap motion.

13. A snap acting device comprising a metal member to be actuated having a mounted end and a free end portion provided with an abutment, a flexible actuating lever extending in the same general direction as the member to be actuated and having a free end portion provided with an abutment and each of said abutments having spaced inner and outer edges, a strip metal spring having an arcuate-shaped portion, said spring having one portion engaging the inner edge of the abutment on the actuating member and another portion engaging the inner edge of the abutment on the member to be actuated, said spring being provided with spaced openings and being rockable on said abutments during movement of said lever relative to the member to be actuated, means for maintaining said spring in operative association With said abutments including a projection extending from the abutment of the member to be actuated which is loosely received in one of the openings in said spring and a projection extending from the actuating lever which is loosely received in the other opening in said spring, said spring being held under compression between said abutments and having suicient force to maintain the free end of said lever in spaced misaligned relation to the free end of said member, and an actuator applied to said lever intermediate its ends for moving said lever against the force of said spring to a critical position in which the free end portion of said lever is substantially in alignment with the free end portion of said member to rock said spring on said abutments and the movement of said lever in the same direction beyond its critical position being effective in rocking said spring to a position in which a third Portion of said spring engages the outer edge of the abutment on said lever and a fourth portion of said spring engages the outer edge of the abutment on the member to be actuated to throw said lever and said member in opposite directions with a snap motion.

14. A snap acting switch comprising a stop, a stationary contact, an actuating lever consisting of a flat strip of metal having a free end portion extending beyond said stop with one of its dat sides arranged opposite to the stop and the free end portion of said lever being provided with an abutment including a tongue, an arm to be actuated having a free end extending in the same general direction as said lever and being provided with an abutment including a tongue, and each of said abutments having spaced inner and outer edges, a contact carried by said arm which is movable into and from engagement with the stationary contact and said lever being biased away from said arm into engagement with said stop, a, strip metal spring having one portion engaging the inner edge of the abutment on said lever and being loosely held in engagement therewith by the tongue on said lever and another portion engaging the inner edge of the abutment on said arm and being loosely held in engagement therewith by the tongue on said arm, said spring being held under compression between said abutments and being arranged to impart a stress to that portion of the lever which extends beyond said stop and to exert a force on the free end portion of said arm and said spring being rockable on said abutments during movement of said lever relative to said arm, an actuator for applying force to said lever intermediate said stop and the mounted end of said lever to move the free end portion of the lever to a critical position in which the free end portion of the lever is substantially in alignment with the free end portion of said arm and the movement of said lever beyond its critical position in the same direction being effective in providing an additional rocking movement of said spring upon said abutments to a position in which a third portion of said spring engages the outer edge of the abutment on said lever and a fourth portion of said spring engages the outer edge of the abutment on said arm to thereby change the direction of the force of said spring to such an extent that it throws said lever forwardly in the same direction it was actuated and the arm in a direction opposite to the movement of said lever with a snap motion, and the bias on said lever being suicient to cause it to return to its original position when the force on said actuator is released.

15. A snap acting switch comprising a stop, a stationary contact, an actuating lever consisting of a flat strip of metal having a supported end and a free end portion with one of its iiat sides arranged opposite to said stop and being movable into engagement therewith and the free end portion of said lever being provided with an abutment, an arm to be actuated having a free end extending in the same general direction as said lever and being provided with an abutment, and each of said abutments having spaced inner and outer edges, a contact carried by said arm which is movable into and from engagement with the stationary contact and said lever being biased away from said arm into engagement with said stop, an arcuate-shaped spring provided with spaced apertures, said spring having one portion engaging the inner edge of the abutment on said lever and a second portion engaging the inner edge of the abutment on said arm, means for maintaining said spring in operative association with said lever and said arm including a projection on said lever extending loosely through one of the apertures in the spring and a projection on said arm extending loosely through the other aperture in said spring, said spring being held under compression between said abutments and having suflicient force to stress that portion of the lever which extends beyond said stop and to exert a force on the free end portion of said arm, and an actuator applied to said lever intermediate said stop and its mounted end for moving the free end portion of said lever to and beyond a critical position in which the abutment on said lever is substantially in alignment with the abutment on said arm and the movement of said lever beyond its critical position being effective in changing the direction of the force of said spring to such an extent that a third `portion of said spring engages the opposite edge of the abutment on said arm and throws it in a direction opposite to the movement of said lever with a snap motion, and the bias on said lever being sufficient to cause it to return to its original position when the force on said actuator is released.

16. A snap acting device comprising a bimetallic member having a free end portion provided with an abutment, an arm to be actuated having a free end portion provided with an abutment, each of said abutments having spaced inner and outer edges, a strip metal spring having an arcuate-shaped portion, said spring having one portion engaging the inner edge of the abutment on said member and a second portion engaging the inner edge of the abutment on said arm, said spring being held under compression between the edges of said abutments and having suicient force when held under compression to maintain the free end portion of the bimetallic member and the free end portion of said arm in spaced misaligned relation to each other and said spring being rockable upon said abutments to change the direction of the force of said spring during movement of the bimetallic member relative to said arm, said bimetallic member being movable upon variation in temperature against the force of said spring to a critical position in which the free end portion of the bimetallic member is substantially in alignment with the free end portion of said arm, and the movement of the free end portion of the bimetallic member beyond its critical position in the same direction being effective in providing an additional rocking movement of said spring upon said abutments to a position in which a third portion of said spring engages the outer edge of the abutment on said arm and a fourth portion of said spring engages the outer edge of the abutment on said bimetallic member to thereby change the direction of the force of said spring to such an extent that it throws the bimetallic member forwardly in the same direction it is moved by variation in temperature and the arm in a direction opposite to the movement of the bimetallic member with a snap motion.

17. A snap acting device comprising a bimetallic member having a free end portion provided with an abutment including a tongue, an arm to be actuated having a free end portion provided with an abutment including a tongue and each of said abutments having spaced inner and outer edges, spring means having one portion engaging the inner edge of the abutment on said member and being held loosely in engagement therewith by the tongue on said member and another portion engaging the inner edge of the abutment on said arm and being loosely held in engagement therewith by the tongue on said arm, said spring means being held under compression between the edges of said abutments and having suicient force to maintain the free end portion of the bimetallic member and the free end portion of said arm in spaced misaligned relation to each other and said spring means being rockable upon said abutments to change the direction of the force of said spring means during movement of the bimetallic member, said bimetallic member being movable upon variation of temperature against the force of said spring means to a critical position in which the free. end portion of the bimetallic member is substantially in alignment with the free end portion of said arm, and the movement of said bimetallic member beyond its critical position in the same direction being effective in providing an additional rocking movement of said spring means upon said abutments to a position in which a third portion of said spring means engages the outer edge of the abutment on said arm and a fourth portion of said spring means engages the outer edge of the abutment on said member to thereby change the direction of the force of said spring means to such an extent that it throws the bimetallic member forwardly in the same direction it is moved by the variation in temperature and the arm in the opposite direction with a snap motion.

18. A snap acting switch comprising a bimetallic member having a mounted end and comprising a bimetallic coil arranged adjacent the xed end and a bimetallic arm formed integral with and extending from the bimetallic coil which arm has a free end portion including a tongue, a stationary contact, a flexible arm to be actuated having a free end portion including a tongue, a movable contact carried by the flexible arm in spaced relation to its free end, spring means having one portion rockable on the free end portion of the bimetallic arm and being held loosely in engagement by the tongue on the bimetallic arm and another portion rockable on the free end portion of the ilexible arm and being held loosely in engagement therewith by the tongue on the flexible arm during movement of the bimetallic arm, said spring means being held under compression between the free end portions of said arms and having sufcient force to maintain the free end of the bimetallic arm in spaced misaligned relation to the free end portion of the flexible arm and the movable contact in engagement with the stationary contact and to flex the free end portion of the ilexible arm which extends beyond the movable contact, and said bimetallic member being movable upon variation in temperature to move the free end portion of the bimetallic arm against the force of said spring means to a first position in which the bimetallic arm is substantially in alignment with the free end portion of the flexible arm to rock said spring means upon the free end portions of said arms, and said bimetallic arm being also movable in the same direction beyond said first position to rock said spring means upon the free end portions of said arm to a second position in which the force of said spring means throws the ilexible arm in the opposite direction with a snap motion to disengage the movable contact from the stationary contact.

19. A snap acting device comprising a bimetallic member having a mounted end and a free end portion provided with an abutment, an arm to be actuated having a free end provided with an abutment, each of said abutments having spaced inner and outer edges, a strip metal spring having an arcuate-shaped portion and being provided with spaced apertures, said spring being held under compression between said abutments with one portion 0f the spring engaging the inner edge of the abutment on said member and another portion engaging the inner edge of the abutment on said arm and said spring having suicient force when held under compression to maintain the free end portion of the bimetallic member and the free end portion of said arm in spaced misaligned relation, means for maintaining said spring in operative association with the bimetallic member and said arm including a projection on the bimetallic member extending loosely through one of the apertures in the spring and a projection on said arm extending loosely through the other aperture in said spring, said bimetallic member being movable upon variation in temperature to move its free end portion against the force of said spring to a nrst position in which the free end portion of the bimetallic member is substantially in alignment with the free end portion of said arm to rock said spring upon said abutments and the movement of the bimetallic member in the same direction beyond said position being ellective in providing additional rocking movement of said spring upon said abutments to a second position in which a third portion of the spring engages the outer edge of the abutment on said arm and throws said arm in a direction opposite to the movement of the bimetallic member.

20. A snap acting switch comprising a bimetallic member having a mounted end comprising a bimetallic coil arranged adjacent the mounted end and a bimetallic arm formed integral with and extending from said coil which arm has a free end portion provided with an abutment, a flexible arm to be actuated having one end mounted in proximity to the xed end of the bimetallic member and a free end portion provided with an abutment, and each of said abutments having spaced inner and outer edges, a movable contact carried by the flexible arm in spaced relation to its free end, an arcuateshaped spring having spaced openings, said spring being disposed between the free end portions of the bimetallic arm and the flexible arm with one portion engaging the inner edge of the abutment on the bimetallic arm and a second portion engaging the inner edge of the abutment on the flexible arm, means for maintaining said spring in operative association with said abutments including a projection extending from the abutment on the bimetallic arm which is loosely received in one of the openings in said spring and a projection extending from the abutment on the flexible arm which is loosely received in the other opening in said spring, said spring being held under compression between said abutments and having sufficient force to maintain the free end of the bimetallic arm in spaced misaligned relation to the free end of the flexible arm and the movable contact in engagement with the stationary contact and to flex the free end portion of the flexible arm which extends beyond the movable contact, and said bimetallic member being movable upon variation in temperature to move the free end p0rtion of the bimetallic arm against the force of said spring to a rst position in which the bimetallic arm is substantially in alignment with the free end portion of the flexible arm and to rock said spring upon said abutments and said bimetallic arm being also movable upon variation in temperature in the same direction beyond said first position to rock said spring upon said abutments to a second position in which a third portion of said spring engages the outer edge of the abutment of the bimetallic arm and a fourth portion of said spring engages the outer edge of the abutment on the exible arm to throw said arm in opposite directions with a snap motion.

21. A snap acting switch comprising a bimetallic member having a mounted end and comprising a bimetallic coil arranged adjacent its mounted end and a first bimetallic arm formed integral with and extending from the bimetallic coil which arm has a free end portion including a tongue, a stationary contact, a second flexible bimetallic arm to be actuated having one end mounted in proximity to the fixed end oi the bimetallic member and a free end portion including a tongue, the first bimetallic arm being movable upon variation in temperature in one direction and the sec-ond bimetallic arm having the tendency to movein the opposite direction during the same variation in temperature, a movable contact carried by the second bimetallic arm which is spaced from its free end, spring means having one portion rockable on the free end portion of the rst bimetallic arm and being held loosely in engagement therewith by the tongue on the rst bimetallic arm and a second portion rockable on the free end portion of the second bimetallic arm and being held loosely in engagement therewith by the tongue on the second bimetallic arm, said spring means being held under compression between the free end portions of said arm and having sufficient force to maintain the free end portion of the iirst bimetallic arm in spaced misaligned relation to the free end portion of the second bimetallic arm and the movable contact in engagement with the stationary contact and to flex the free end portion of the second bimetallic arm which extends beyond the movable contact, and said bimetallic member being movable upon variation in temperature to move the free end portion of the rst bimetallic arm against the force of said spring means to a position in which the iirst bimetallic arm is substantially in alignment with the free end portion of the second bimetallic arm and to rock said spring means upon the free end portions of said arms and the rst bimetallic arm being also movable in the same direction beyond said first position to rock said spring means upon the free end portions of said arms to a second position in which the force of said spring means and the stress on the second bimetallic arm caused by the variation in temperature throw the second bimetallic arm in the opposite direction with a snap motion to disengage the movable contact from the stationary contact.

22. A snap acting device comprising a movable stop, a member to be actuated having a mounted end and a free end portion provided with an abutment, a ilexible actuating lever extending in the same general direction as the member to be actuated and being movable to and beyond a critical position in which the free end portion of said lever is substantially in alignment with the free end portion of said arm, said lever having a mounted end and a free end portion provided with an abutment which extends beyond said stop, a strip metal spring, said spring having one portion rockable on the abutment on said lever and another portion rockable on the abutment on said member during movement of said lever relative to said member, said spring being held under compression between said abutments and, having sufficient force when held under compression to maintain said lever in engagement with said stop and to flex the free end portion of said lever which extends beyond said stop, and an actuator for applying force to said stop to move the free end portion of the lever against the force of said spring to and beyond a critical position and said spring being rockable upon said abutments during movement of said lever to a position in which the force of the spring throws said arm in a direction opposite to the movement of said lever. y

23. A snap acting device comprising a bimetallic member having a free end portion provided with an abutment having spaced inner and outer edges, an arm to be actuated having a free end portion provided with an abutment having spaced inner and outer edges, a bowed spring disposed between said abutments and having one portion engaging the inner edge of the abutment on the bimetallic member and another portion engaging the inner edge of the abutment on said arm, said spring being held under compression between the inner edges of said abutments and having sunicient force when held under compression to maintain the free end portion of the bimetallic member and the free end portion of said arm in spaced misaligned relation to each other and said spring being rockable upon said abutments to change the direction of the force of said spring during movement of the bimetallic member relative to said arm, said bimetallic member being movable upon variation in temperature against the force of said spring to a critical position in which the free end portion of the bimetallic member is substantially in alignment with the free end portion of said arm, and the movement of the free end portion of the bimetallic member beyond its critical position in the same direction being effective in providing an additional rocking movement of said spring upon said abutments to a position in which a third portion of said spring engages the outer edge of the abutment on said arm and a fourth portion of said spring engages the outer edge of the abutment on said bimetallic member to thereby change the direction of the force of said spring to such an extent that it throws the bimetallic member forwardly in the same direction it is moved by variation in temperature and the arm in a direction opposite to the movement of the bimetallic member with a snap motion.

24. A snap acting device comprising a bimetallic member having a free end portion provided with an abutment including a tongue, an arm to be actuated having a free end portion provided with an abutment including a tongue and each of said abutments having spaced inner and outer edges, a strip metal spring having one portion engaging the inner edge of the abutment on said member and being held loosely in engagement therewith by the tongue on said member and another portion engaging the inner edge of the abutment on said arm and being loosely held in engagement therewith by the tongue on said arm, said spring being held under compression between the edges of said abutments and having sufficient force to maintain the free end portion of the bimetallic member and the free end portion of said arm in spaced misaligned relation to each other and said spring means being rockable upon said abutments to change the direction of the force of said spring during movement of the bimetallic member, said bimetallic member being movable upon variation of temperature against the force of said spring to a critical position in which the free end portion of the bimetallic member is substantially in alignment with the free end portion of said arm, and the movement of said bimetallic member beyond its critical position in the same direction being effective in providing an additional rocking movement of said spring upon said abutments to a position in which a third portion of said spring engages the outer edge of the abutment on said arm and a fourth portion of said spring engages the outer edge of the abutment on said member to thereby change the direction of the force of said spring to such an extent that it throws the bimetallic member forwardly in the same direction it is moved by the variation in temperature and the arm in the opposite direction with a snap motion.

EVERARD F. KOHL.

28 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 935,226 Peterson Sept. 28, 1909 1,231,527 Long June 26, 1917 1,516,195 Lewerenz Nov. 18, 1924 1,762,075 Petersen June 3, 1930 1,905,823 Dybvig Apr. 25, 1933 1,934,605 Tarleton Nov. 7, 1933 2,036,295 Piffath Apr. 7, 1936 2,068,374 Carlson Jan. 19, 1937 2,170,748 Eaton Aug. 22, 1939 2,218,908 Fonseca Oct. 22, 1940 2,237,705 Kohl Apr. 8, 1941 2,260,964 Wilms- Oct 28, 1941 2,284,644 Dubilier June 2, 1942 I 2,295,463 Fetter Sept. 8, 1942 2,458,518 Kohl Jan, 11, 1949

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