US2433710A - Contact structure for electric switches - Google Patents

Description

.Dec. 30, 1947. H. E. SCHLEICHERQ 2,433,710

CONTACT STRUGTURE FOR ELECTRIC SWITCHES Filed July 15, 1942 66 45 zz 67 y '1 .5. HAROLD E.SCHLE|CHER a By 2:219 arZ-Z'arneys 'IIIIIIIIIIII. r 'I'II/IIIIII'II Patented Dec. 39, 1947 CONTACT STRUCTURE FOR ELECTRIC SWITCHES Harold E. Schleicher, West Hartford, Conn, as-

slgnor to The Arrow-Hart & Hegeman Elect'rc Comp nv, Hartford, Conn., a corporation of Connecticut Application July 15, 1942, Serial No. 451,047

1 12 Claims.

This invention relates to an improved contact assembly for an electric switch, and is particularly useful in electromagnetically-operated switches, but is not limited thereto.

It is an object of the invention to provide a contact assembly wherein the fixed and movable contacts are both reversible in such manner as to enable the whole switch, or individual contact sets thereof, to be normally open or normally closed, as desired.

Another object of the invention is to provide a mount for fixed and movable contacts that can be reversed as a completely assembled unit for the purpose of changing the switch from a normally closed to a normally open type.

Another object of the invention is to provide interchangeable contacts-both fixed and movable-in order to reduce the cost-of tools and to lower manufacturing costs and inventories.

Another object of the invention is to provide for ready removal and replacement or reversal of the contacts and to facilitate fabrication of the contact assembly.

Another object is to provide for holding the operating means in a certain position to facilitate the removal or reversal of the movable contact assembly.

Another object of the invention is to create a contact-structure that will permit its application to switches requiring many multiples of contacts and that will permit the contacts to be multiplied in the direction of movement.

Another object of the invention is to provide a readily removable cover that will facilitate inspection and will serve as means to hold and guide the movable contact assemblies in their paths of movement.

Other objects and advantages will become apparent as the invention is described in connection with the drawings.

In the drawings- Fig. l is a side elevation view, partly in section, of an electric switch mechanism embodying my invention.

Fig. 2 is a plan view of a portion of the construction of Fig. 1 with the cover removed.

Fig. 3 is a transverse section taken along line 8-3 of Fig. 2.

Fig. 4 is a fragmentary transverse section taken along line 4-4 of Fig. 2.

Fig. 5 is a perspective view, partly exploded, of the movable contact assembly employed in the invention.

Referring to the drawing, the invention is shown as applied to an electromagnetically-operated switch I0 whose armature moves a metallic frame having spaced parallel horizontal side arms l2 connected at one end by a transverse bar l4. The movement of the bar l4 in response to operation of the electromagnet causes operation of movable contact assemblies, hereinafter more fully described. The bar [4 is provided with vertical slots into which fit reduced portions I 8 of the movable contact carriers, hereinafter described.

The contact structure is mounted within an insulating base 20 having recesses, such as 22, for the reception of the stationary and movable contact members.

The base 20 is preferably symmetrical and secured to a foundation plate l9 by bolts 25 that are symmetrically positioned so that the base can be reversed or turned through to cause it, and the parts it carries, to face in an opposite direction. The base preferably has two levels 24 and 26, the higher level 26 being in the center of the base with levels 24 at each side thereof. On the levels 24 are mounted four identical stationary contact members 30, stamped from sheet metal. These members comprise flat portions, bolted upon the level 24, with side edges 30s bent down to lie in parallel grooves to keep the members from turning. A contact bearing finger 30a depends from one of the bent down side edges of each of said contact members and extends in a laterally-offset direction so as to lie within contact-receiving cavities in the base. Preferably contact buttons of silver 30c, or other suitable contact metal, are applied to the ends of the contact portions for engagement with similar contact buttons of movable contacts, hereinafter described. The contact members 30 are one of complementary pairs of such members. the other member 32 being mounted upon the upper level 26 of the base. The members 32 are like members 30 except that the contact fingers on the same sides of the respective members depend in opposite directions. The contact members 30 and 32 are complementary in the respect that they may be interchanged and reversed in position on levels 24 or 26, the member 32 being substituted for the member 30, and vice versa. The result of this substitution and reversal will be that the contacts, instead of facing to the left as in the upper portion of Fig. 2, will face to the right, as in the lower portion of Fig. 2. One advantage of this ability to reverse and-interchange the contact terminal members is that the switch may be thereby converted from a normally open type to a normally ClQfiQd type of switch if, at the same time, the movable contacts are reversed, as hereinaiter described.

To connect the contacts of the members 30 and 32, there are provided removable contact assemblies shown in detail in Fig. 5. The elements of these assemblies are as follows: A cylindrical rod 40 of insulating material (having near its ends reduced necks l8, hereinbefore mentioned as fitting within the slots ii of the switch operating frame bar [4) acts as a carrier for the stamped sheet metal bridging contact members 48. In the mid-portions of the rods 40 are reduced sections 42 and 44 on which are mounted yoke members 46 to engage and position the bridging contact members. The yoke members may be stamped from sheet metal into the form shown in Fig. 5, being provided with parallel head portions 46a, 46b, lying in radial planes and joined by a bar portion 460 parallel to the axis of the rod 40. For engagement within apertures in the bridging contact members, there are provided lugs 46d bent out of the plane of the head portions into alignment with each other and parallel with the axis of the rod 40. For mounting the yoke members 46 upon the rod 40, radially-extending slots are provided to permit the yoke members to be slid laterally upon the reduced sections 42 and 44, the heads of the yoke members thereafter being crimped into permanent engagement with said reduced sections. The bridging contact members 48 are provided at their central portions with slots 48s to permit these contacts to be slid laterally upon the carrier and thereafter to be moved axially to engage one or the other of the lugs 46 within one or another of the two apertures provided therefor in the contact. By this means, the bridging contacts are held against rotary movement relative to the carrier 40. To hold the contact in assembled relation to the rod and yoke, the coil springs 58 are wound around the reduced portions 42 and 44 Within the yoke, in a position pressing the movable contact against the inner face of that head of the yoke toward which the contact member faces. The contact member may face in. either direction, depending upon the desire to have the contacts normally o en or normally closed. After the contacts and the yokes are mounted upon the rods, the movable contact assembly is complete and may thereupon be located within the base 20 in position for the movable contact members to engage their respective stationary contacts.

For mounting the movable contact assemblies and for guiding their to and fro sliding movement, there are provided in opposite side Walls of the base 20 aligned bearing notches 2! which also align with bearing grooves 23 in the midortion of the base. To hold the contact assemb ies against rotary motion and to keep the bridging contact members with their contact buttons al gned with the contact buttons of the stationary contact members. the b ttons u on the ends of the bridgi g contact members which are lowermost in the contact receiving recesses are so located as to abut against the bottom or a ainst the side walls of said recesses ee Fi 3) in res o se to any rotary turning effort. In o der to hold the c n act a sembli s. or more particularly the rods 40 thereof. Within the grooves and no ches 23 and 2! respectivev, and also at the same time to provide a shield and a cover for the conta t strucfurethere is provided a hood or cover member 52 of generally rectangular configuration. which is ada ted to overl e the cening recesses therein. The lower peripheral edges of the hood l2 lie upon the levels 24 o! the base and overlie the notches 2!. In a similar manner, centrally-located ribs or partitions I4 are formed within the hood on opposite sides to separate the contact pairs at the left (Fig. 2) from those at the right of the base, and at the same time to overlie the grooves 24. The hood, therefore, provides means to hold the contact assemblies in position and to guide them in their paths of movement as they are caused to move by the electromagnetic operating mechanism.

In order that the hood 52 may be quickly and easily removed when desired and in order that it may be-quickly and eflectively secured at all other times, there is provided a spring-pressed pin I60 with an enlarged flattened head I52 which extends through a slot or hole in the center of the hood. Upon pulling up the head IE2 and turning it the cover may be effectively and quickly locked into position.

Any convenient or suitable means may be provided to secure the contact members 30, 32, to the base and to connect them to bus bars or terminals. In the embodiment shown, the contacts 32 are secured by the bolts passing through the base and engaging in bus bars beneath the base, while the contact members 30 are held by terminal screws extending through apertures in these members and taking into hollow rivets within circular bores in the base.

Contact structure herein disclosed possesses the valuable ability to have its movable contact assemblies, or its movable contact members 48 and stationary contact members 30 and 32 interchanged for one another or, in other words, reversed, providing normally open contacts, when placed as shown in the upper half oi! Fig. 2, or normally closed contacts, when reversed and placed as shown in the lower half of Fig. 2.

In the event of changing both pairs of the normally closed contacts of the lower portion of Fig. 2 to normally open contacts (as in the upper part of Fig. 2), the reversing of the stationary contacts 30 and 32 will be accompanied by reversing the contact assembly as a unit. Alternatively, if it should be desired to have one set of the contacts controlled by one assembly normally closed and the other set normally open, that can be readily accomplished by reversibly interchanging only one set of the fixed contacts and by removing the bridging contact from the mounting rod 40 and reversing it and replacing it on the rod 40 with the coil spring on the opposite side, so as to press the movable contact in the direction opposite to its former pressing.

Additional flexibility oi the invention is provided in the ability to reverse the entire mount of the fixed and movable contacts by reversing the base, and the parts carried by it, as a unit. Thus, the switch can be, at once, changed from normally open to a normally closed type, or vice versa.

When the invention is applied to an electromagnetic switch, as illustrated in the drawing, it

is common to provide a spring, such as 60, to move the electromagnet armature, when disengaged, from energized position. Preferably the spring is attached at one end to a part of the fixed supporting structure of the electromagnet and has its other end attached to one of the pivotally mounted supporting arms 62 for the armature-supporting frame l2i4. This spring normally tends to move the frame and the contacts tral portion of the base and the contact 9iv- 75 0f the switch to the left in Figs. 1 and 2. In order to hold the armature and its frame, and therefore also the movable contacts, in an intermediate position between the normally open and normally closed positions, there is provided a locking means comprising a button 64 which is centrally located and slides in a bushing 65 on a fixed plate 66 that is mounted on the magnet field piece. A spring 68 coiled about the bushing 65 pressing on the underside of the enlarged button-head normally urges the button upwardly. To the lower end of the button, a Z-angle bracket 69 is affixed with one end extending over an upwardly-inclined tongue IS on the armaturemoved cross bar l4. If the armature is energized or is manually pressed to the right in Figs. 1 and 2, and the button is then depressed and the armature thereafter released, the end of the bracket 69 will catch behind the inclined tongue IS. The parts are so proportioned and placed that, in that position, the bracket 69 will hold the frame bar It (and the contact assemblies it moves) intermediate the open and closed posi- .tions of the contacts. From that intermediate position, the movable contact assemblies can be lifted with ease for reversal or replacement, since in that position none of the contacts are engaged, regardless of their arrangement, nor is there any other deterrent to removal of the contact assemblies after the cover 52 has been taken off to expose them. To release the locking en- 'gagement, the armature may be moved manually to the right, or the electromagnet may be energized, whereupon the spring will press the button up to its normal inactive position.

From the foregoing, it will be apparent that the novel contact structure herein disclosed is extremely flexible in use and may be assembled in a number of useful combinations, and it may be reassembled, as occasion may demand, in any of a number of difi'erent combinations even after the switch has been completely fabricated and put into use.

Many modifications within'the scope of my invention will occur to those skilled in the art. Therefore, I do not limit the invention to the specific form and arrangement of the contacts as illustrated and described.

I claim:

1. In an electric switch, a pair of fixed contacts, a movable contact carrier comprising a rod, a movable contact member having a slot opening into its side edge to enable it to be mounted upon and removed from said carrier by movement sidewise from said carrier, a yoke member having a slotted head on said carrier and having a portion interengaging said movable contact member, and spring means urging said movable contact member axially to cause said movable contact member to become interengaged with said yoke member and permitting said movable contact to move axially along said carrier to adjust itself as said movable contact member and fixed contacts become engaged.

2. In an electromagnetic switch, an insulating base, a pair of fixed contacts mounted thereon, a movable contact assembly slidably mounted in said base and having a movable contact member engageable with said fixed contacts, electromagnetically contact operating mechanism to which said contact assembly becomes removably attached as said assembly is placed in said base, and a hood covering said contacts and engaging said assembly to hold it in its mounting and concomitantly to hold it in engagement with said electro-magnetic operating mechanism.

3. In an electric switch, a plurality of pairs of fixed contacts, a carrier, a plurality of spaced contact members mounted on and relatively movable with respect to said carrier and engageable with respective pairs of fixed contacts, means for moving said carrier from one position to another, said contacts being engaged by said contact members in one of said positions, said fixed contacts being interchangeable in reversed positions, and said carrier and contacts carried thereby being reversible as a unit for causing the movable contact member to be disengaged from said contacts in said one position and engaged with them in the other position of said moving means, said carrier being removable independently of the fixed contacts while the latter are in assembled condition.

4. In an electromagnetic switch, an insulating base, a pair of fixed contacts mounted thereon, a movable contact assembly slidably mounted in said base and having a movable contact member engageable with said fixed contacts, electromagnetic contact operating mechanism to which said contact assembly becomes removably attached as said assembly is placed in said base, a hood covering said contacts and engaging said assembly to hold it in its mounting and concomitantly to hold it in engagement with said electromagnetic operating mechanism, said fixed contacts being engaged by said movable contact member when moved into one position by said operating mechanism, said fixed contacts being interchangeable in reversed positions, and said movable contact member being reversible for causing said movable contact member to be disengaged from said fixed contacts in said one position and to engage them in another position of said operating mechanism.

5. An electric switch as claimed in claim 2 wherein the contact assembly comprises a carrier, a yoke fixed on said carrier and with which said movable contact member is engageable, and spring means holding said movable contact member and yoke in assembled position on said carrier and permitting said movable contact member to move relative to said carrier upon coming into engagement with said fixed contacts.

6. In an electromagnetically-operated switch, a base, fixed contacts mounted thereon, movable contact assemblies having movable contacts engageable with said fixed contacts, operating means detachably engaging said assemblies, an electromagnet to actuate said operatin means, normally inactive means that is manually movable into engagement with said operating means to hold said operating means in a certain position wherein the fixed and movable contacts are disengaged, facilitating the detaching of said assemblies from said operating means, and means to automatically return said holding means to inactive position on energization of said electromagnet.

7. In an electric switch, an insulating base, a pair of fixed contacts mounted thereon, a movable contact assembly comprising a rod extending beyond said base at both ends and guided by said base adjacent its end portions, a movable contact member mountable on the said portion of said rod by lateral movement, yoke means on said rod having axial portions engaging said movable contact member to prevent relative rotation of said member and rod, and spring means pressing upon said movable contact member to hold it in assembled relation with said rod and yoke means, a removable cover enclosing said contacts and having a portion engaging said movable contact 7 assembly to hold it within its mounting and to guide its movement.

8. In an electric switch, an insulating base, a pair of fixed contacts mounted thereon, a movable contact assembly comprising a carrier, on which said movable contact member is mountable by lateral movement, said carrier extending beyond said base at both ends and guided by said base adjacent its end portions, means on the mid portion of said carrier engaging said movable contact member, and spring means pressing said movable contact member axially along said ca'r rier to cause said movable contact member to become interengaged with said means on the carrier and permitting said movable contact to move axially along said carrier to adjust itself as said movable contact member and fixed contacts become engaged, and a removable cover enclosing said contacts and having a portion engaging said movable contact assembly to hold it within its mounting and to guide its movement.

9. In an electric switch, a pair of fixed contacts, a movable carrier, a yoke permanently fixed upon said carrier, a movable contact member having a laterally open bearing recess permitting lateral assembly on and detachment from said carrier, said contact member being mountable on said carrier in either obverse or reverse positions, oppositely extending lugs on the yoke one or the other of which engages said contact member, spring means holding said contact member inter-engaged with either one or the other of said lugs depending upon whether said contact member is obversely r reversely placed on said carrier.

10. In an electric switch, a pair of fixed contacts, a contact carrying rod, a yoke on said rod, a movable contact member mountable on said rod in obverse or reverse positions, means on said yoke and contact member interengaging to prevent relative rotation, said contact member having a laterally open recess to permit assembly on said rod by lateral movement, spring means pressing said movable contact member axially along said rod in one direction when said contact member is obversely placed and in the opposite direction when said contact member is reversely placed but in each instance holding said contact member, yoke and rod assembled.

11. In an electric switch, a plurality of pairs of fixed contacts, a carrier, a plurality of spaced contact members mounted on and relatively movable with respect to said carrier and engageable with respective pairs of fixed contacts, means for moving said carrier from one position to another, said contacts being engaged by said contact members in one oi said positions, said fixed contacts being interchangeable in reversed positions, and said carrier and contacts carried thereby being reversible as a unit for causing the movable contact members to be disengaged from said contacts in said one position and engaged with them in the other position of said moving means, said carrier being removable independently of the fixed contacts while the latter are in assembled condition, electromagnetic contact operating mechanism to which said carrier is detachably connected, and a hood covering said contacts and engaging said carrier at opposite ends to hold it in its mounting and concomitantly to hold it in engagement with said operating mechanism.

12. In an electric switch, a pair of fixed contacts, a contact carrying rod, a movable contact member having a laterally open recess to permit mounting on said carrier, means to retain said movable member on said rod while permitting limited axial movement thereon, means tor moving said rod from a first to a second position, said contacts being engaged by said contact member in one of said positions, said fixed contacts being interchangeable in reversed positions and said movable contact member being reversible within its mounting on said rod for causing said movable contact member to be disengaged from said contacts in said one position and engaged with them in the other position on said carrier,

HAROLD E. SCHLEICHER.

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

UNITED STATES PATENTS Number Name Date Re. 20,676 Wilms et al. Mar. 22, 1938 836,666 Brown Nov. 27, 1906 1,121,567 Mcwilliams Dec. 15, 1914 1,350,924 Eaton Aug. 24, 1920 1,438,522 Devers Dec. 12, 1922 1,571,292 Meyer et a1. Feb. 2, 1926 2,106,581 Unwin Jan. 25, 1938 2,139,519 Schmitt Dec. 6, 1938 2,152,496 Owens Mar. 28, 1939 2,239,031 Bierenteld Apr. 22, 1941 2,273,545 Van Valkenburg Feb. 17, 1942 2,276,698 Pierce Mar. 17, 1942 2,283,795 Dahl May 19, 1942 2,304,972 Van Valkenburg et al. Dec. 15, 1942 Certificate of Correction Patent No. 2,433,710. December 30, 1947.

HAROLD E. SGHLEIGHIER It is hereby certified that error appears in the printed specification of the above numbered patent requirin correction as follows: Column 6, line 67, claim 7, for the words said portion rea mid portion; and that the said Letters Patent should be read with the correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 16th day of March, A. D. 1948.

THOMAS F.- MURPHY,

Am'atant Uomzrm'saioner of Patents.

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