US2958069A

US2958069A - Electrical device

Info

Publication number: US2958069A
Application number: US621834A
Authority: US
Inventors: David C Redick; John R Wilson
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1956-11-13
Filing date: 1956-11-13
Publication date: 1960-10-25
Anticipated expiration: 1977-10-25

Description

Oct. 25, 1960 D. C. REDICK ET AL ELECTRICAL DEVICE 2 Sheets-Sheet 1 Filed Nov. 13, 1956 Fig.3

Fig. 4

INVENTORS John R. Wi/son y David C. Red/ck Their Attorney Oct. 25, 1960 D. c. REDICK ET AL 2,953,069

ELECTRICAL DEVICE Filed Nov. 13, 1956 2 Sheets-Sheet 2 INVENTORS John R. Wilson y Dav/'0' 6. fled/ck The Afforney United States Patent" ELECTRICAL DEVICE David C. Redick, Anderson, and John R. Wilson, Pcndleton, Ind., assignors to General Motors Corporation,

Detroit, Mich., a corporation of Delaware Filed Nov. 13, 1956, Ser. No. 621,834

3 Claims. (Cl. 339-220) This invention relates to electrical equipment and more particularly to the securement of a terminal-contact member in a base of insulating material that is relatively brittle and has a relatively thin cross-section.

Electrical equipment such as switches are frequently assembled with an insulating part that provides a base formaintaining the switch contacts and terminals for the switch in position and in electrical contact with each other. The bases of these parts usually have a relatively thin cross-section to reduce the overall size of the switch and to realize economies in manufacture. Heretofore, the contacts for the switch were usually formed of rivets which were peened over the base of an L-shaped terminal so the head of the rivet would provide a stationary contact and extend from one side of the base and the shank of the terminal would project from the other side. When, however, the contact and terminal is formed as a single unit, difficulties are encountered in large scale manufacturing operations in anchoring the unit in a base of relatively thin crosssection if the base is formed of relatively thin brittle material.

It is an object of the present invention to secure a terminal and contact member in a thin base of insulating material by a method which will provide a part for a switch or other electrical units which is serviceable and economical to manufacture.

It is a further object of the present invention to pro vide a terminal for an electrical switch, which terminal has a pair of pre-cut ears that are spaced from an integral contact portion and to secure the terminal in a base of relatively thin cross-section of relatively brittle material by bending the pre-cut ears toward the con tact portion and into engagement with the material of the base.

A still further object of the present invention is to provide a terminal which is preformed from a strip of metal to have an integral fiat contact portion and a pair of pre-cut ears that are located on the edges of the shank of the terminal a predetermined distance from the contact portion so the terminal may be inserted through a slot in a base of relatively thin brittle material and to securely maintain the terminal and contact member in position in the slotted base which is recessed to receive the contact portion by bending the ears to form a curve so the ends of the ears engage the base.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying v drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure l in perspective shows a bottom view of a portion of the base of relatively thin brittle material with a terminal contact arranged to be inserted in a slot therein and a terminal contact secured therein.

Figure 2 in perspective shows a top view of a por- ICC.

tion of the base in Figure l showing a terminal contact secured in a slot therein.

Figure 2A is a perspective view similar to Figure 2 but showing the terminal ears bent in the same direction;

Figures 3 and 4 diagrammatically show one form of the apparatus for securing the terminal contact in the.

base.

Figure 5 shows a portion of the apparatus which will cause the pre-cut ears on the terminal to be curvedly bent to engage the base. 7

Figure 5A is a view similar to Figure 5 but wherein" Figure 7 diagrammatically shows the apparatus in Fig ure 6 after the ears have been bent into a securing position, as shown in Figure 8-. a

Figure 9 is a partial view taken along line 9-9 in Figure 6.

Figure 10 is a partial view taken along line 10-10 in Figure 7.

Figures 11 and 12 are a front and side view showing another arrangement for bending the ears of the terminal in Figure 1. The present invention is directed to a method and apparatus for securing a terminal and contact part in a base of insulating material. In the drawings, the numeral 20 designates the terminal and contact part and the numeral 22 designates the base. The base 22 is preferably formed of a molded phenolic condensation product such as Bakelite, and has a relatively thin crosssection. The

" base 22 has a slot 24 extending through its thin crosssection between the upper face 26 and the lower face 28. Included in the base is a recess 30 which has one of its ends in register with the slot. The recess 30 further is formed to have a predetermined size, shape, and depth. The terminal 20 is formed from a unitary strip of metal to have a shank portion 32 and a flat contact portion 34 which is integrally formed on one end of the shank portion to extend substantially at right angles thereto. Disposed intermediate the contact portion 34 and the end 36 of the shank portion is a pair of shoulders 38. These shoulders are formed along the edges of the shank at a predetermined distance from the contact portion. This distance being greater than the thickness of the base 22. For purposes of description, the portion of the shank 32 between the shoulders 38 and the contact portion 34 will be called the anchoring portion 35 and the portion between the shoulders 38 and the end 36 will be called the terminal portion 33. Also included in the anchoring portion 35 along the edges thereof from the shoulders 38 toward the contact portion 34 are precut slits 50. These pre-cut slits together with the shoulders 38 form a pair of cars 42 on the edges of the anchoring portion 35. The contact portion 34 of the terminal is sized to be snugly received in the recess 30 and has a thickness when positioned in the recess to be flush with the bottom surface 28 of the base. In this connection, it is to be pointed out that the contact portion 34 may have a greater width than the Width of the anchoring portion 35. The slot 24 and the recess 30 in the base 22 are arranged so the contact portion will be received tightly in the recess while the anchoring portion 35 of the shank 32 will be tightly received in the slot 24 and the ear portions 42 will extend above the top surface 26.

After the terminal and contact 20 is thus positioned in the base 22, it is placed in an apparatus which will Patented Oct. 25,- 1960.;

be hereinafter described which will deform the ears 42 to secure the terminal and contact 20 in the base 22.

In Figures 3, 4 and 5, one form of the apparatus for deforming the ears 42 is shown. In Figure 3 of the drawings, the assembled base 22, and terminal 20 are placed in a work-holder 50. This work-holder is arranged so an anvil 52 will be in tight engagement with the base 22 and the contact portion 34. A means including the member 53 which is guided by member 55 will raise and lower a die 54 relative to the anvil 52. The die 54 is slotted as at 56 to receive the shank portion 32 of the terminal. The walls of the slot 56 on end 58 of the die are curved or rounded as shown in Figure 5. This chamfered, curved or rounded portion 60 is located on the opposite sides of slot 56. These portions 60 will engage the cars 42 and cause the ears to be curvedly bent toward the base so that the shoulder portion 38 engages the base and tightly holds the terminal and contact in position in the base. The ears 42, of course, follow the curvature of the portion 60 during the securing operation.

In Figures 6 to of the drawings, an embodiment is shown whereby the ears 42 are twisted into securing position. In this embodiment, the base 22 with the inserted terminal-contact is positioned by a workholder and an anvil, not shown. A punch 62 which is slotted at 64 is moved downwardly over the shank 32 by a means not shown. This punch has a diameter equal to the width of the terminal portion 33 of the contact terminal part 20. A sleeve 66 is fitted around the exterior of punch 62. This sleeve 66 has a notch 68 on its end 70 which is sized to receive the ears 42. The apparatus is arranged so the punch 62 is vertically movable in part 72 to exert pressure on the terminal to tightly press contact portion 34 in recess 30. The sleeve 66 is rotated on the punch 62 by means of a gear 71. The sleeve 66 has a curved surface at the end of the notch 68. This curved surface 74 will bend the ears 42 into engagement with the base as the sleeve is rotated. The curved surfaces 74 extend on opposite sides of the sleeve 66 as shown in Figures 9 and 10, and when the sleeve is moved from the position shown in Figure 9 to the position shown in Figure 10, the ears 42 will be bent in opposite directions to accomplish the securing operation.

In Figures 11 and 12 of the drawings, another method for bending the ears is shown. In this arrangement, a punch, not shown, is used to spread the ears 42 as shown in Figure 11.

As heretofore stated, the terminal part 20 is provided with a pre-sheared set of ears 42. These pre-sheared ears will reduce the force required to bend or curve the ears over the relatively brittle base 22. This has been shown in tests to reduce the tendency of the terminal to bend over during the forming operation and will substantially eliminate any cracking of the brittle base during the securing operation. This fact is especially manifest when several terminals are being secured in a single base simultaneously. In this connection, it is to be noted that the steady pressures are maintained on the punches and sleeves and no impact loads are to be employed during this securing operation. It is recommended that if more than one terminal is to be secured in any one base, individually loaded punches be em- 4 ployed to compensate for the variations in tolerances which might occur in the base. It has been found that an improved result is realized if the contact portion 34 is initially formed to have a slight back angle relative to the shank portion. This will improve the setting of the contact in recess 30 after the ears 42 are formed over the top surface 26 of the terminal. In connection with the pressures on the punches employed, it has been found that the pressures may range from 150 pounds per punch to 400 pounds and that the movement of the sleeve relative to the punch 62 in the order of 30 will prove adequate to accomplish the securing operation.

Another point to be noted in connection with securing of the cars is that the ears may be formed to extend in opposite directions as shown in Figure 2 or the ears may be formed to extend in the same direction as shown in Figure 2A. If this result is to be realized, one of the curved surfaces on the punch 64 will be reversed as shown in Figure 5A rather than as shown in Figure 5.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come within the scope of the claims which follow.

What is claimed is as follows:

1. A fixed terminal assembly for an electric switch comprising; a base of insulating material having a relatively thin cross-section separating two substantially parallel surfaces, a recess in one of said surfaces, a slot extending through said base connecting said recess with an opposite surface of the base, a metal terminal member formed of resilient strip metal material having a male terminal portion snugly fitting within said slot and a fiat contact portion disposed at substantially right angles to said terminal portion fitting within said recess, said recess having a depth substantially equal to the thickness of said contact portion whereby said contact portion and said base form a planar surface, and a pair of pre-cut ears extending from said terminal portion and bent down into direct contact with the surface of said base opposite the surface of said base having said contact portion, said contact portion being initially at slightly less than a right angle to said terminal portion and being bent to substantially a right angle to said terminal portion and held in this position when said ears are bent down, whereby said ears and contact portion tightly clamp said base to prevent movement of the terminal member with respect to the base.

2. The terminal assembly according to claim 1 wherein the ears are bent in the same direction.

3. The terminal assembly according to claim 1 wherein the ears are bent in opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS 1,531,411 Perry Mar. 31, 1925 2,056,036 Catron et al. Sept. 29, 1936 2,291,660 Spencer Aug. 4, 1942 2,755,453 Cloutier July 17, 1956 2,782,392 Stolle Feb. 19, 1957 FOREIGN PATENTS 56,447 Norway Apr. 20, 1936