US3239628A - Teflon coated contact separator - Google Patents

Description

March 8, 1966 N. LESSER 3,239,628

TEFLON COATED CONTACT SEPARA'I'OR Filed May 22, 1963 2 Sheets-Sheet 2 I NVEN TOR Norfon Lesser United States Patent 3,239,628 TEFLU N COATED CGNTAGT SEPARATOR Norton Lesser, 648 Burton Ave, Highland Park, Ill. Filed May 22, 1963, Scr. No. 282,498 4 Claims. (Cl. 200-404) This invention relates in general to switches and relays and more particularly to both improvements in the arrangements disclosed in application No. 98,699, now abandoned, and to other improvements in the adjustment, operation and control of contacts for relays and switches.

In one arrangement disclosed in application No. 98,699, now abandoned, an insulating plastic sheet structure was moved on energization of a coil to either separate a pair of contacts or permit a pair of contacts to engage. The contacts were carried by springs or blades normally adjusted so that the contacts engaged and the position of the insulator determined whether the contacts were of a normally make or a normally break type. The insulator or contact operator, preferably comprised a Teflon or similar material such as Delrin, which had the quality of lubricating the surface with which it was engaged. Teflon, although it is one of the most heat resistant insulators may still fail after only moderate use.

It is therefore one purpose of this invention to provide an arrangement for enhancing the life of the insulator. To achieve this purpose the contact operator sheet is comprised of a heat conducting body such as a glass fabric or other substance, which is either coated, impregnated or otherwise treated with Teflon to improve its lubricating qualities.

While the aforementioned application disclosed the concept of aligning the contacts along a single line having a constant distance from the support structure, this arrangement is dil'hcult to achieve in practice. It is therefore another object of the present invention to provide methods and arrangements for achieving this result with greater precision and economy.

In addition the aforementioned application disclosed the use of a plastic sheet structure having apertures therein for permitting the contacts to operate. While this arrangement is feasible it presents a problem since the apertures had to be positioned with considerable precision with respect to each other and with respect to the contacts since the insulator travel is quite small. On the other hand since the insulator was a yielding or plastic material it is extremely difficult to force a leading edge between the contacts unless it is peripherally supported. Further in the aforementioned application in order to secure a C type of contact operation in which one set of contacts is opened and another closed by one contact of the set, two insulators were suggested for use between the contact sets.

It is therefore another object of the present invention to provide an improved plastic insulator or sheet arrangement for operating the contacts, especially where considerable numbers of the same are provided, and for achieving C type contact operation with but a single insulator.

The present invention contemplates several arrangements for avoiding problems relating to contact adjustment and alignment. These arrangements include the adjustable positioning of an insulator block holding one row of springs with respect to another insulating block and/ or the assembly of several rows of springs in a common insulator block and a simple forming arrangement for bringing the contacts into engagement without individual adjustment of the springs.

When separate inuslator blocks are used, adjustment in the position of the springs carried by the blocks may be secured in very simple and economical fashion by ice making the blocks movable with respect to each other and fastening them in an adjusted position. Another arrangement utilizes a spring connection between the insulator blocks with the spring connection being adjusted until the contacts are properly engaged. This also has the advantage of enabling a plurality of contacts to mate under the tension of the spring connection only, irrespective of the number of contacts to be controlled. A large number of contacts may thus be operated under minimum power since they need be moved only against the tension of the spring connection.

The invention also contemplates the provision of an improved arrangement for the operation of a plurality of contacts in a sealed enclosure such as done with reed switches or mercury wetted relays. Thus in a reed switch the contacts are enclosed in a capsule and are not controlled in a direct fashion by an armature, or if so, the coil causing actuation must be enclosed. To overcome this difliculty the invention contemplates the use of a flexible wall for the enclosure to permit direct operation of the contacts from a coil located outside of the enclosure.

The above and other objects of the present invention will become apparent on examination of the following specification and claims together with the accompanying drawings, wherein;

FIG. 1 is a top elevational view of a relay incorporating the insulator sheet structure.

FIG. 2 is a sectional view taken along the line 2-2 in FIG. 1 illustrating the contacts and insulator in an exaggerated relationship.

FIG. 3 is a side elevational view of the relay shown in FIG. 1.

FIG. 4 is a front end view of the relay shown in FIG. 1.

FIG. 5 illustrates one arrangement utilizing a spring connection between insulator blocks for adjusting a row of contacts.

FIG. 6 illustrates a similar arrangement to that in FIG. 2 but utilizing an arm on the armature for operating the contacts instead of a sliding insulator sheet.

FIG. 7 is a perspective view illustrating another arrangement for adjusting the relationship between rows of springs to create repsective mating contacts.

FIG. 8 illustrates one arrangement for simultaneously forming a plurality of contacts along a common line.

FIG. 9 is a top view of the arrangement illustrated in FIG. 8.

FIG. 10 illustrates an arrangement for simultaneously coining a plurality of contact surfaces on springs fixedly held in a common block.

FIG. 11 illustrates the principles of the invention as applied to an enclosed type contact assembly.

In FIGS. 1, 3 and 4 a relay is generally indicated by the reference characters 10, while in FIGS. 5 and 6 a relay is indicated by the characters 10a and 1% respectively. Each relay comprises a coil 12 carried on a bobbin having spool heads 14. A core 16 extends through the bobbin and beyond the spool heads 14. An L-shaped heelpiece 18 having an arm 18a is provided for supporting the core and coil from one end of the core 16. The other arm of the heelpiece 18 extends parallel to the long axis of the core and an armature 20 is rotatably supported on a pivot 21 at the end of the parallel arm. A spring illustrated at 22 in FIGURES 3 and 5 is used to bias the armature into a particular position. The armature 20 extends past the free end of the core and it is attracted to the core on energization of the coil 12. An electrical circuit for energizing the coil is completed through terminals 23.

Each relay 10, 10a and 10b is provided with a COH- tact bank indicated at 24 in FIGS. 1, 3 and 4 and at 24a and 24b respectively in FIGS. 5 and 6. The contact bank 24 comprises a plurality of modified C type contacts each being composed of a center spring 26 arranged in a row 27 and a pair of adjacent springs 28 and 30 arranged in rows 31 and 32 on opposite sides of row 27 as best seen in FIGS. 2 and 3. Each of the springs 28 and 30 are adapted to normally engage opposite sides of a respective center spring 26 along a single line. The spring 26 is adapted to be separated from either spring 28 or 30 by an insulating plastic sheet 33. Actual precious metal contacts may be provided at the position of engagement or the springs themselves may be of contact material. The springs 26, 28 and 30 are all fastened in an integrally formed insulating block 34. The block 34- is mounted on a tab 35 extending from the arm 18a of the heelpiece in the case of relay It The plastic insulator 33 traverses the springs of bank 24 and it is supported either directly on the armature 20 as shown in FIG. 5 or by a bracket 36 carried by the armature 20 as seen in FIGS. 3 and 4. The plastic or yieldable insulator 33 may be fixed to the armature 20 or bracket 36 in any one of a number of manners. Usually a slot in the insulator 33 engages over the bracket 36 or armature 20. This slot is then filled with epoxy to form a solid engaging body between the armature and insulator 33 and ensures movement of insulator 33 therewith.

The insulator 33 comprises a heat conducting body 33, as seen in FIG. 2. The body 38 may be a glass fabric sheet either impregnated or coated with polytetrafluoroethylene 40 known as Teflon, or similar material. In any event in the insulator 33, which is usually only about .01", the body 38 acts as a heat sink and evidently conducts heat more rapidly than Teflon alone to thereby preserve the characteristics of the insualtor 33 for many contact operations.

It will be noted that the insulator 33 has a slot 42 therein spaced adjacent the line of engagement or contact between the springs 26, 28 and 3t) and traversing all of the contacts. One edge 43 of the slot normally holds springs 26 and 28 out of engagement while springs 26 and 30 are permitted to engage. When the coil 12 is energized the edge 43 is moved so that springs 26 and 28 engage, while movement of the back edge 44 of the slot separates springs 26 and 30. This use of a single insulator 33 with a slot simplifies the provision of an edge structure for control of large numbers of contacts and permits the simultaneous operation of more than twenty-five contacts. Thus by using an elongate slot the plastic is peripherally supported while the line of alignment between the slot edge and the contacts may be easily seen and adjusted since the movement takes place toward or away from said line. The apertures or holes of the previously described insulator was more difiicult or expensive to fabricate and more difficult to align since alignment had to be made for all aperture edges and it did not present a visually continuous line which could be matched for movement across the line of contact engagement. In addition the slot permits the C type of contact operation between contacts 26, 28 and 30 with but a single insulator structure.

The block 34 may comprise any suitable insulating material in which the springs 26, 28 and 30, for example, may be fastened. To form the springs before they are assembled to the block may result in a number of problems in aligning the contacts along a single line and a common plane; wherefor it is desirable to form the same after they are assembled to the block 34. The springs 26, 28 and 30 are therefore assembled in the block 34 in respective rows and are then engaged in a bending jig 46 seen in FIGS. 8 and 9 for forming the springs into engagement. The jig 46 comprises a horizontally extending bar 48 which is supported at opposite ends between a pair of posts such as 50. A second bar 52 is provided 4 and it is supported on a slotted block 54. Posts such as 53 are also provided for supporting the ends of bar 52.

Initially the springs 26 and 30 are engaged over opposite sides of bars 43 and 52 with the insulating block 34 held securely against block 54. The springs 26 and 28 thus pass through respective slots 58 in block 54 with the springs 26 aligned with the upper side of block 54.

An arm 6t) which is guided, for example, on suitable pins, not shown, is then forced against springs 30 to deform them between bars 48 and 52 by a desired amount as illustrated by the dotted line 62. The springs 26 are permitted to move downward because of the slots 58 under the pressure as seen by dotted line 64. When the arm 69 is withdrawn and the contact assembly disengaged from jig 46 the springs 26 and 30 are in normal engagement. The degree of engagement between the respective springs is dependent on the amount of deflection imparted by the arm 60. In order to secure a desired final deformation of the springs they must be deflected by an amount exceeding the final desired deformation. The bars 48 and 52 are clamped in position during the deformation of springs 30 and their spacing determines the angle at which the wire 36 approaches the contact point 65.

The position of springs 26 and 30 is then reversed in the jig 46 and the operation repeated to deform springs 28 until they normally engage springs 26 when disengaged from the jig 46. In this case the springs 26 and 28 may both be deflected downward as indicated by broken lines 62, and the slots 58 permit this movement to occur without interference. The forming procedure, of course, may be utilized with variable numbers of spring rows as is obvious and enables multiple numbers of springs to be simultaneously formed along a desired line and in a desired plane. This simplifies the assembly with insulator 33 since the edge of the slot may then be easily aligned at a desired increment from the contacts. This is very important since the stroke of the armature is now limited and may only be between .02" and .03" at the core 16.

The contact banks 24a and 24b seen in FIGS. 5 and 6 each have a plurality of spring pairs comprising springs 70 and 72 projecting in respective rows from respective insulating blocks 74 and 76. If desired, another row of springs can be provided to construct a C type contact arrangement such as illustrated by bank 24. The block 74 of bank 24a is mounted on the respective heel piece 18 by means of a bracket 78 and in the case of bank 24b, block 74 is mounted in the heelpiece 18 by means of a bracket 80.

The two blocks 74 and 76 of the respective banks 24a and 24b are secured together by one or more spring members 82. The spring members 82 are adjusted so as to bring the formed or contact portions of the springs 70 and 72 of the respective banks 24a and 24b into engagement under a desired degree of pressure. The original deformation of the springs 70 or 72 may, for example, be formed as explained for bank 24.

To operate the springs 70 and 72 of bank 24a, an insulating sheet 33 such as described for relay 10 is mounted on the associated armature 2t and a slot 43 therein is either moved between the springs or from between the springs 76 and 72 as the coil 12 is energized. The choice is dependent on whether it is desired to operate the springs as make or break contacts. The spring 22 is used to return the armature 20 and sheet 33 to normal so that the springs resume their unoperated condition.

To operate the springs 7 ti and 72 of bank 241; a pressure:

member 84 is mounted on the armature. The member 84 is moved by the armature to operate the springs 70. against the tension of the springs 82 and is returned to normal by the tension of springs 82 on de-energization of the coil. If it is desired to use this arrangement for type C operation the member 84 is simply engaged with a center row of wires and it moves them from engagement with one row into engagement with another row.

In this manner one or more spring members 82 may carry a plurality of contact springs for engagement with a minimum adjustment, while the force needed to operate the plurality is dependent on the tension of the spring members 82 instead of the combined tension of all the spring pairs. It will be noted that in this type of arrangement the wires 70 and 72 need not necessarily always be spring material since the spring function is borne by spring members 82.

In FIG. 7 an alternate adjustment arrangement is illustrated. In this arrangement the two insulating blocks 86 and 88 having respective rows 90 and 92 of contact wires are joined by a bracket member such as 94. Each bracket 94 has slots 96 therein. The brackets are connected to the respective blocks 86 and 88 by screws 98, for example, or by rivets with the distance between the blocks 86 and 88 being adjusted until respective springs 90 and 92 are brought into engagement. The screws 98 or rivets are then tightened to hold the springs engaged. If desired, the bracket member 94 may be of spring material so that the construction operates similar to banks 24:! and 2412.

In FIG. a simple arrangement for coining a flat surface on the contacts is illustrated for use with a plurality of rows of wires such as shown in contact bank 24. When a flat or coined surface is desired at the position of contact this is often preferably done after the wires are assembled in card 34. To accomplish this a pair of similar coining bars 100 and 102 are provided. Each has a plurality of spaced apart apertures 104 to permit their passage over wires 28 and 30 respectively. If desired a single slot traversing the wires may be used.

The bars 100 and 102 also have a flat surface 106 which are brought into alignment with opposite sides of wires 26. One or more stops 108 are provided on one or both coining bars. When the bars are moved towards each other the flat or coining faces 106 flatten the respective wires 26 to a depth determined by the stops 108.

In FIG. 11 an enclosed type of switch relay 120 is illustrated. The enclosure comprises a glass or other wall portion 124 used for partially enclosing a sealed chamber 126 in which are located plurality of spring pairs 128, 130, etc. The springs may be wetted by mercury, for example, in any well known manner and one spring of each pair is provided with a suitable buffer 132 to permit operation of all the springs by an armature arm 134. The arm 134 is engaged with a flexible wall portion 136 which completes the enclosure formed by wall portion 124. A second arm 138 outside of the enclosure engages against the flexible wall 136 and is adapted to be operated by a relay armature in any well known manner. When operated it causes partial collapse of the flexible wall to exert pressure against arm 134 to operate the contact pairs 128 and 130. The wall portion 136 is flexible, but not corrugated. If desired the armature arm 138 may project through wall 136 to operate the spring pairs directly. The wall 136 comprises an impervious flexible sheet material having a chemically inert coating such as Teflon.

With this arrangement the armature may efliciently operate the contacts since the wall 136 flexes. Thus the volume of chamber 126 may remain constant since it usually contains gas under heavy pressure, but the spatial disposition of the chamber may be altered easily to accommodate the various armature movements.

What I claim is:

1. A relay comprising an armature, a coil energized for moving said armature a predetermined increment, one row of cantilever springs, a second row of cantilever springs each engaging a respective spring of said one row along a single line traversing the longitudinal axis of said springs, a third row of cantilever springs each engaging a respective spring of said one row of springs along said line, and a plastic insulator carried by said armature for movement therewith and having a slot therein receiving said one row of springs with a portion of said insulator adjacent one side of said slot located between said one and second row of springs without disengaging any one of said one and second rows of springs and another portion of said insulator adjacent the other side of said slot being located between said one and third row of springs along said single line to disengage each one of said one and third row of springs whereby respective springs of said one and third rows of springs engage in response to movement of said other portion from said single line and respective springs of said one and second rows disengage in response to movement of said one portion towards said line.

2. A combination comprising a pair of normally engaged metal contacts conducting electrical current which produces an arc of a temperature suflicient to erode said contacts on separation of said contacts to disrupt said current, a sheet material having heat conductive properties and a self-lubricating surface different than said material, and means for slidingly moving said sheet and surface between said contacts to separate said contacts and disrupt said current.

3. A combination comprising a pair of normally engaged metal contacts conducting electrical current which produces an arc of a temperature suflicient to erode said contacts on separation of said contacts to disrupt said current, a glass fabric sheet material of heat conductive properties having a self-lubricating surface of polytetrafiuoroethylene, and means for slidingly moving said sheet and surface between said contacts to separate said contacts and disrupt said current.

4. A combination comprising one metal contact, a second metal contact, a third metal contact, said second and third metal contacts arranged to independently normally engage said one contact to complete respective circuits conducting electrical current, which produces an arc of a temperature suflicient to erode the engaged contacts on separation of the engaged contacts, a flexible sheet material of heat conductive properties having a selflubricating surface different than said material and positioned between said one and second contacts and having a slot formed in said material aligned with said one and third contacts to permit engagement between said one and third contacts, and means for slidingly moving said material and surface between said one and third contacts to disrupt the circuit completed thereby and to align said slot with the said one and second contacts to permit said one and second contacts to engage.

References Cited by the Examiner UNITED STATES PATENTS 2,802,074 8/1957 Pass 20061.19 2,844,675 7/ 1958 Edgar 20061.19 2,854,544 9/1958 Shovic 200151 X 2,908,780 10/1959 Walters 20087 2,992,307 7/ 1961 Reifel 200 3,001,046 9/1961 Racz, et al. 20087 3,045,089 7/ 1962 Russell 200166 3,075,281 l/1963 Spooner 29155.55 3,099,735 7/ 1963 Roeser 200166 3,139,669 7/1964 Gwyn 29-155.55

FOREIGN PATENTS 1,077,785 3/ 1960 Germany.

BERNARD A. GILHEANY, Primary Examiner.

R. N. ENVALL, J R., Assistant Examiner.

Claims (1)

1. 2. A COMBINATION COMPRISING A PAIR OF NORMALLY ENGAGED METAL CONTACTS CONDUCTING ELECTRICAL CURRENT WHICH PRODUCES AN ARC OF A TEMPERATURE SUFFICIENT TO ERODE SAID CONTACTS ON SEPARATION OF SAID CONTACTS TO DISRUPT SAID CURRENT, A SHEET MATERIAL HAVING HEAT CONDUCTIVE PROPERTIES AND A SELF-LUBRICATING SURFACE DIFFERENT THAN SAID MATERIAL, AND MEANS FOR SLIDINGLY MOVING SAID SHEET AND SURFACE BETWEEN SAID CONTACTS TO SEPARATE SAID CONTACTS AND DISRUPT SAID CURRENT.

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