US2232243A - Electric switching mechanism - Google Patents

Description

ELECTRIC SWITCHING MECHANISM File d June 24, 1939 2 Sheets-Sheet l HI 6 E [2 V i 4 I E Z A E Pg J. 26

. //\/Z/E/\ T F ALBERT L. JUDSON Feb. 18, 1941. 232,243

ELECTRIC SWITCHING MECHANISM Filed June 24, 19:59 2 Sheets-Sheet 2 nvflvv 70R ALBERT 1.. JUDSON TTERA/E Pat ent ed is, 1941' PATENT OFFICE "2,232,243 EL TSW TG W MG Albert 1. riiasbitfroraaim, one, as ignmto L. n

- Tecple CompanaPortland, Oreg.

Applicatiolilunel 24", 19ss',fseria1- No. 280,937 .10 Claims. (c1. zoo-:67)

- This invention relates to improvements inelec- 'tric switching mechanisms of that type commonly employed with .condition' affected elements and more particularly tothat type of snapeactionelectric rswitches employing resilient, forces, op-

posed by, magnetic' attraction to provide snapaction.

' Objects of theinvention are the provision for; firm make of-fcontact, and a rapid break or, contact with a minimum of mechanical energy input in which may be readily'inccrporated a condition-afiected'element, and certain other advanofiset'eportion ll adapted to engage in its upwardj. ....moven ent the armature l2 pivotally mounted at l3 and formed in detail with a tongue tageous features apparent in the following hisclosure. g 15 In the drawinf's:

Figure 1 represents a view of a longitudinal.

vertical section of the switch in the closed adjustment. 1 I

Figure 2 represents a view in longitudinal vertical section showing the switch. as 'the parts v l rf 4 appear in the open adjustment.

Figure 3 represents a longitudinal vertical section of an alternative form of the switch in which a bimetallic thermostat-element is substi- I tuted for one of the parts shown in the other two figures.

Figure 4 is an end elevation as viewed from the le ft in Figure 1. I

Figure 5 is a sectional endview taken on the line 5-:5 ofFigurel.

Figure 6 is a sectional end viewtaken on the line 6-6 ,of Figural.

' Figure 7*is a sectional plan view taken along the line 'I-lofFigure' 1. p I 5 Figure-8 is a perspective viewof the invention. Referring now 7 more particularly -to the drawings: e

The essence of this invention resides in the means arrangedand adapted to employ a spring switch arm in double strain in connection with certainrigid, pivotally mounted elements to provide for an enhanced celerity of movement of the contact point in. the opening operation and a firm contact pressure in the closed adjustment.

Considering that the amount of energy used to operate the switch is of a small. fixed quantity, improved action requires that this actuating energy beresolved in a novel manner to effect the desired results;

A frame I is secured to a dielectric base 2 in I which are fixed suitable terminals 3 and 4 elec- -trically connected to a spring switch-arm 5- carrying a contact point 6 and a fixed contact point 1, respectively. The switch-arm 5 is normally formed in the shape in which it is shown a spring l9.

in Figural, that is to say, of such a form as would provide for the separation of the contact "p'ointsi and J as shown inFigure 2. The fixed end of the spring- 5 is secured to the frame I by screws as 8. Intermediate the endsof the spring 6 '5; a pair of laterally spaced journals as .9 are formed integrally upon "the spring and rotatably support'a small roller I0 journalled therein. Ri-

gidity/is imparted to that portion of spring 5 -0 between the journals 9 and the contact 6 by a 1 ,--longitudinal rib depressed in the spring.

" The rr'e'e na of the spring is formed with an M in close proximity to the axis of mounting l3, adapted to bear upon the roller I0, and a rearwardly extending bearing point 15 upon which a thrust-member l6 bears. Were the switch arm 5 not biased upwardly the portion 530 ll through its engagement with armature I2 would constitute a lost motion coupling. Because of the bias no such coupling is present. Actually the portion II is provided solely as a safety breaker and is not intended to engage armature 25 -l2 until switch arm 5 is at its free or upper The thrust-member I6 is formed integrally upon the free end of the lever i'L in turn pivotally 5 mounted on the frame I at l8. -A spring I9 is mounted upon a rearward extension 20 of the lever I! in combination and in contactrwith a rigid slide 2| longitudinally adjustable along the screw 22 to alter the effective length of the Ari actuator which may be a push button or other convenient means to apply a force to actuate the switch is indicated by the broken line figure 23.

Switches of this type used in conjunction with 45 condition control apparatus are required to respond to a relatively fixed energy input repre sented in difierent applications by difierent forces and different distances through which the forces act. ,Theslide 2| allows of adjusting the effec- 50 tive length of'the spring 19, to adapt the switch for use with a variety of condition registering the spring 5 is subjected to flexure. As the armature i2 is attracted to the permanent magnet' 24, prior to closure relatively great force is brought to bear upon the roller l0 and is of such magnitude as to bring the contact points 8 and I together, and further, to strain the spring 5 out of its normal rectilinear form to that form in which it is shown in Figure 1.

Because of the attitude of the surface of the tongue M which contacts the roller III as referred to the arcuate paths traversed thereby respectively, a valuable mechanical advantage is provided. The tongue [4 may be disposed, as experience indicates, in such an attitude as will provide for a relatively great amplitude of movement of the armature l2 and a relatively small and consequently more forcible movement of the roller l0, switch-arm 5, and hence of the .contact 6.

This mechanical advantage, it will be recognized, is not of a constant value for all positions of the afi'ected parts. This characteristic accrues from the particular relative disposition of the roller ill, the axis of the pivotal mounting l3 and the fixed end of the switch arm 5, and is availed of to provide a heavy contacting pressure, or make, and a relatively rapid movement of the point 6 after the contact is broken, while requiring relatively little energy input to effect the break.

Opening of the switch is effected 'by a deflection of the spring I9 in response to a force applied at the free end thereof. At a certain limit of fiexure of the spring l9, determined by the strength of the magnet 24 acting on the armature I2, the potential energy thus invested is resolved into certain dynamic forces in the parts actuated thereby.

The armature i2 is forced upwardly against the attraction of the permanent magnet 24, which force attenuates very rapidly and at a faster rate than that attenuation characteristic of the spring l9,'providing for a more efficacious value of the total force relied upon to accelerate the armature l2 from a state of rest to that desirable velocity at which the electrical contact is broken.

It will be apparent that movement of the contact 6 would occur simultaneously with that movement of a point in the armature l2 in aposition therewith'if the spring 5 were a rigid member by virtue of the rigid connection provided for by the tongue I, roller Ill. and journals 9. Since, however, the spring 5 is not rigid, between screws 8 and journals 9, and is strained, or bowed, downwardly, as shown in Figure 1, the armature l2 will move initially in rapid acceleration without causing any movement of the contact point 6. The strain in spring 5, however, will be in a measure relieved by the upward movement of the tongue I and ultimately .the contact point 5 will rise away from the stationary point 1 at a rapidly accelerated rate clue to the proportionately great force exerted by the spring 5 in returning to its normal position as shown in Figure 2. I

Now it is to be observed that as the pressure upon the roller II is relieved, the strain in the spring 5 will act to supplement the force of the spring IS in accelerating the movement of the armature l2. Relieving the strain on spring 5 operates to allow it to raise the point I, eflecting a clean and instantaneous separation of the points I and 1 in a kind of whipping action.

The offset portion ll of the spring 5 serves II. It is to be noted particularly that this engagement will occur as .the armature is moving at a rapid rate with an impact of sufiicient force to tear apart the contacts 'when lightly fused and provide a quick and eifective .break under abnormal conditions.

This engagement of the armature l2 with the extension H does not normally occur until after the points 5 and I have been separated by .the resolution of the potentials invested in .the switch-arm 5 as described.

In the alternative form shown in Figure 3, a bimetallic element 26 replaces the spring IQ of the switch as shown in Figures 1 and 2 and contains within itself the means of storing potential energy, in the form of strains, to perform a function identical with that of the spring IS, in addition to its inherent properties of registering temperature vaniations. Other parts of the switch, which are similar to the parts used in the other form are indicated by similar numerals with prime exponents. This bimetallic element is conveniently mounted upon a standard 21 rigidly secured to the base 2'.

While I have shown a particular form of embodiment of my invention I am aware that many minor changes therein will readily suggest themselves to others skilled in the art without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to .protect by Letters Patent is:

1. In a switch mechanism a stationary contact, a resilient member, a movable contact carried by said resilient member and normally biased thereby, anoscillatory armature, coupling means adapted to connect said resilient member and said armature, said coupling means being associated with said member and said armature at points of reduced movement, respectively, a magnet cooperating with said armature normally to displace said movable contact in opposition to its bias and switch operating means associated spring-mounting for the one .of said contacts near the extremity of the spring mounting and adapted to constrain the said contacts together and further to strain thesaid spring-mounting beyond that value at which the said contact is perfected, and resilient means associated in opposition with said magnetically actuated means to suddenly remove the constraint of said sprin mcunting to effect the separation of the said contacts.

with said armature in opposition to said magnet. 2. In electric switches, normally separated stal 4. In electric switches, normally separated stationary and spring-mounted contacts, magnetically urged means bearing angularly upon the spring-mounting for the one of said contacts at a point of reduced movement and adapted to constrain thesaid contacts together, and a resiliently coupled condition-affected element associated in opposition with said magnetically urged cam, the paths of travel of said cam and said projection crossing at an angle to cause movemeans to separate the said contacts.

5 In electric switches, normally separated stationary and spring-mounted contacts, magnetL' cally urged variable rate mechanical means including a cam portion disposed at a point of reduced movement thereof and bearing upon 'the spring-mounting for the one of said contacts to constrain the said contacts together, and resilient means associated in opposition with said removed from the'contact and adapted to constrain the said contacts together, and resilient means associatedin opposition with said magnetically urged means to separate the said contacts, wherein said magnetically urged meansis fitted with a delayed-action engagement for said spring-mounting near the contact fixed thereto whereby said contacts may be forcibly separated in an emergency.

'7. In electric switches, normally separated stationary and spring-mounted contacts, magnetically urged means bearing upon the spring mounting for'the 'one of said contacts adapted to constrain the said contacts together, resilient means associated in opposition withsaid magnetically urged means to separate the said contacts and means associated with and adapted to vary the spring rate oi said resilient means.

8. In a switch, a stationary contact, a resilient member supported at one of its ends and biased and oscillatory about a point spaced from the support for said resilient member, said armature including a cam portion, a projection formed onthe resilient member between its supported end and the contact and disposed in the path of said ment of said armature under the urge of said magnet to close said contacts and further deflect said resilient member.

9. In electric switches, a stationary contact, a movable contact carried by a spring member and normally separated from the stationary contact, a roller journaled near the fixed end of the spring mounting for the movable contact, a magnetically attracted pivoted member having a tongue projecting therefrom near the pivot, said tongue being arranged to, engage said roller with increasing advantage and thereby close and strain said contacts in response to'the magnetic attraction, and resilient means arranged in opposition to said magnetically influenced member .to separate the contacts abruptly.

10. In a switch mechanism, a stationary contact, a resilient member having a movable contact at one of its ends-and fixed at itsopposite end a roller journaled on said resilient member near its fixed end, a magnet, an oscillatory armature influenced by said magnet, said armature including a tongue angularly projecting therefrom near the center of oscillation, said tongue armature under the attraction .of the magnet to thereby close and strain together said contact-s abruptly, and resilient means bearing upon said armature in opposiiton 'to said magnet for open- 40 I ing said contacts in one abrupt motion.

ALBERT L. J UDSON.

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