US2849698A - Composite plates and methods of making them - Google Patents

Description

Aug. 26, 1958 Filed March 15, 1954 A. LOGAN COMPOSITE PLATES AND METHODS OF MAKING THEM 2 Sheets-Sheet 1 ATTORNEY 2 Sheets-Sheet 2 A. LOGAN COMPOSITE PLATES AND METHODS OF MAKING THEM Aug. 26, 1958 Filed March 15, 1954 INVENTOR A. LOGAN BY A TTORNEY COMPOSITE PLATES AND METHODS OF MAKING THEM Alexander Logan, Pikesville, Md., assignor to Western Electric fCompany, Incorporated, New York, N. Y., a corporation of New York Application March 15, 1954, Serial No. 416,125

7 Claims. (Cl. 339198) This nvention relates to composite plates and methods of making such plates, and more particularly to composite platesemployed to support cable terminal during manufacturing and electrical testing thereof, and methods of making such composite plates.

In the manufacture of some types of cable terminals. electrical tests are performed on the individual terminal elements thereof at an intermediate stage of the assembling operations. It is convenient and practical to perform such tests while the partially assembled terminals are still mounted on special fixtures employed to support them during the assembling operations. Certain features of such fixtures are disclosed and claimed in patent 2,729,850 granted January 10, 1957, on a copending application Serial No. 244,810, filed September 1, 1951, by L. S. Dewees.

The apparatus disclosed in the Dewees patent includes a supporting plate composed of steel, one side of which is secured to a coextensive insulating plate composed of phenol fabric (a fabric impregnated with a phenol-formaldehyde type resin). The steel plate and the insulating plate are provided with a plurality of slots aligned in the proper pattern to allow the individual terminal posts of a cable terminal to pass through them. The slots in the insulating plate are made slightly smaller than the slots in the steel plate, in order to keep the terminal posts insulated from each other by preventing them from contacting the sides of the slots in the steel plate. It has been found that the phenol fabric plate shows excessive wear after it has been used repeatedly, and eventually its insulating properties may become impaired.

It is an object of this invention to provide new and improved composite plates and method of making such p ates,

A further object of the invention is to provide new and improved composite plates for supporting cable terminals while manufacturing and testing such terminals, and methods of making such composite plates.

A composite plate illustrating certain features of the invention may include a pair of parallel metal plates having a plurality of slots aligned to permit the individual terminal posts of a cable terminal to extend through the composite plate, the slots in one of said plates being slightly larger than the corresponding slots in the other plate so that the terminal posts extending through the aligned slots are prevented from electrically contacting the plate having the larger slots therein, and a layer of insulating material sandwiched between and bonded to the pair of metal plates.

A method illustrating certain features of the invention comprises the steps of stamping a plurality of slots in a metal plate in a pattern designed to receive the individual terminal posts of a cable terminal, stamping in another metal plate a plurality of slightly larger slots arranged in a similar pattern, placing the plates side by side with the slots therein in alignment, bonding the plates together with an intermediate layer of insulating cement, and cutting a series of diagonal slots in one of the plates to divide this plate into a plurality of isolated segments each of which nited States Patent 2,849,698 Patented Aug. 26, 1958 receives one of the individual terminal posts and insulates them from each other.

A complete understanding of the invention may be obtained from the following detailed description of a composite plate and a method forming specific embodiments thereof, when read in conjunction with the appended drawings, in which:

Figv 1 is a top plan view of a pair of cable terminals mounted on a fixture having a pair of composite plates embodying the invention;

Fig. 2 is a reduced, side elevation of the apparatus illustrated in Fig. 1;

Fig. 3 is an enlarged, fragmentary, vertical section taken along line 33 of Fig. l;

Fig. 4 is an enlarged, fragmentary, plan view of a composite plate embodying the invention, with portion broken away to show details of its construction, and

Fig. 5 is an enlarged, fragmentary, vertical section of a portion of the composite plate shown in Fig. 4.

Referring now to the drawings, the opposite ends of a coiled cable stub 10 are joined to a pair of identical, partially completed cable terminals 1212, in the manner shown in Figs. 1 and 2, while manufacturing operations are performed on the terminals. The coiled cable stub 10 together with the terminals 1212 are supported on a fixture, designated generally by the numeral 14, having a rectangular base 16 and a pair of upright members 18 and 19 secured thereto. The upright member 18 rises from one end of the base 16, and the upright member 19 rises from a point spaced from but near to the opposite end thereof. These upright members function as handles which may be grasped by an operator in lifting and transporting the fixture 14 from one operation to another, and they also serve as supports which enable fixture of this type to be stacked upon each other. The convolutions of the coiled cable stub 10 surround the upright member 19 and thereby hold the cable stub properly positioned.

The base 16 of the fixture 14 is constructed from a pair of parallel channels 21 and 22, which are connected by a pair of cross bars 23 and 24 located near the upright members 18 and 19, respectively. In order to reduce the weight of the fixture 14, the base 16 is preferably made of aluminum. A steel abutment 26 rises vertically from the base 16 at a point intermediate the upright members 18 and 19 but closer to the upright member 19. As shown in Fig. l, the abutment 26 is provided with pivoted clamps 28 and 29 having wing nuts 3030 for clamping opposite ends of the cable stub 10 into position on this abutment. As viewed in Fig. l, the clamp 28 is closed over the cable stub 10 while the clamp 29 is pivoted outwardly into its open position.

The upright member 18 is provided with a pair of identical plungers 34-34, which are mounted threadedly within sleeves 3636 for transverse movement through this upright member when the plungers are rotated. Rotation of the plungers 3434 is accomplished by actuating a pair of operating handles 38-38 secured to the outer ends of the plungers. The inner ends of the plungers are provided with frustoconical tips, such as the tip 40, which protrude inwardly beyond the sleeves 36-36 when the plungers are at the limit of their inward transverse movement through the upright member 18. In this innermost position, the frustoconical tips of the plungers 3434 also project over a horizontal steel support bar 44 mounted transversely of the base 16.

The abutment 26 is provided with a shoulder 46 mounted at the same level as the top surface of the horizontal support bar 44, as shown in Fig. 2. Straddling the channels 21 and 22 at a point intermediate the upright member 18 and the abutment 26 is a transverse block 48. The upper surface of the block 48 is below the level of the upper surfaces of the support bar 44 and the Hing steps. ing operation,'some of the shells were bowed with the ;two.ends the reof higher than the center portion of the shoulder 46. Theblock 48 ismade of an electrical insulating material, such as phenol fabric.

The incomplete cable terminals 12-12 are supported by a pair of elongated compositelplates 50-50, which extend from the support bar 44 to the shoulder 46 'of the 'abutment26. Each of the terminals 12-12 includes an elongated box-like plastic shell 52 having two rows of holes (not shown) formedin' the bottom thereof, and

two rows-of terminal posts 54-54 and 56-56 which extend through the holes and project slightly below the bottom of the shell. These'two rows of terminal posts also'project through the composite plates 50-50 when the terminals 1212 are mounted thereon.

As is shown best in Fig. 2, when the plungers 34-34 have been moved to their innermost position, their frustoconical tips, such as the tip 40, engage one end of the composite plates 50-50 and wedge this end down against the support bar 44. At the same time, the other end of the plates 50-50 is wedged against the shoulder 46 of the abutment 26. As a result of this arrangement,

. a group of the terminal posts 54-54 and 56-56 which are located near the center of the plates 50-50 are pressed'into engagement with the transverse block 48, thereby causing the plates 50-50 to be bent into a bow shape about the block 48 as a fulcrum.

The purpose of this mounting is described in greater detail in the aforementioned Dewees patent. First, the

'two rows of terminal posts 54-54 and 56-56 are electrically connected to a plurality of conductors 60-60 (Fig. l) which emanate from and make up the body of the cable stub 10. These two rows of terminal posts extend downwardly from a plurality of bases, of which the bases 62 and 63, respectively, are shown in Fig. 3, seated in the bottom of the shell 52 in two corresponding rows.

Within the shell 52, a plurality of flat terminals 64-64 liquid casting resin, and the resin is cured at elevated temperatures in an oven to complete the manufacture of the terminals.

The casting resin might be composed of a polyester of a linear polyhydric alcohol and an unsaturated polybasic acid, mixed with a vinyl compound and filler material. The polyester might be a propylene glycol polyester of fumaric, maleic or orthophthalic acid. The vinyl compound may be styrene, and the filler material may be powdered silica to which a small amount of glass fibers may be added. Resins of this general nature tend to polymerize, especially in the presence of small amounts of peroxide catalysts, into hard, dense products, and the polymerization reaction may be accelerated by heating them.

When an uncured resin of this type is poured into an elongated -shell composed of polystyrene, such as the plastic shell 52 described hereinabove, and the resin is cured in the shell by heating it to a suitable temperature,

the resin becomes denser and it shrinks more than it ordinarily would from mere heating and cooling alone. This shrinkage of the-resir1 tends to warp the plastic shells, and-unless special precautions are taken, the shells tend to become distorted. Of course, the narrow, elongated configuration of the shells also contributes to their tendency'to become warped'during the heating and cool- It was found that after the heating and cool- 4 bottoms of the shells, while others tended to twist sidewise.

In order to overcome this tendency and to produce finished products in which the shells are perfectly straight, the shells are bowed, in the manner described hereinabove, in a direction opposite'to that in which they tend to become bowed during the curing and cooling steps. This bowing is just suflicient to counteract that produced during the heating and cooling cycles, and as a result thereof, the molded terminals which finally result are perfectly straight without any upward bowing of the ends thereof. Moreover, the composite plates 50-50 prevent the shells from becoming twisted sidewise during the heating and cooling steps.

The composite plates 50-50 are composite structures composed of an upper metal plate 70, a lower metal plate 72 which is segmental in structure, and a thin layer 74 of insulating material cemented sandwich-fashion between these two metal plates. The'two plates 70 and 72 are approximately coextensive in length and width. The upper plate 70 is provided with two parallel longitudinal grooves 76 and 78, best shown in Fig. 4, which provide clearance for the two rows of bases, of which the bases 62 and 63 are representative, which are seated in the bottom of the shell 52. In the bottoms of the grooves 76 and 78 are formedtwo rows of keyhole shaped slots 80-80 and 82-82, respectively. These slots are spaced at intervals corresponding with the spacing of the terminal posts 54-54 and 56-56 which protrude downwardly from the bottom of the shell 52. Likewise, the segmental lower plate 72 is provided with two rows of keyhole shaped slots 84-84 and 86-86 aligned with and arranged in a pattern corresponding to that of the keyhole shaped slots 80-80 and 82-82 in the upper plate 70. Of course, the intermediate insulating layer 74 must be provided with a plurality of slots 88-88 which are aligned with the slots in the two metal plates.

The enlarged circular portions of the slots 80-80 and 82-82 are of the same sizeas the corresponding circular portions of the slots 84-84 and 86-86. However, the short straight portions of the slots '84-84 and 86-86 are narrower than the corresponding portions of the slots 80-80 and 82-82. This construction permits the terminal posts 54-54 and '56-56 to extend through the slots 80-80 and 82-82 in the upper metal plate 70 without making electrical contact therewith.

Although the terminal posts may make electrical contact with the sides of the slots 84-84 and 86-86 in the'segmental lower metal plate 72, this lower plate is cut into a plurality of separate segments 90-90 in order to insulate the terminal posts from each other. The segments 90-90 are formed by two series of diagonal slots 92-92 and 93-93. Each ofthe diagonal slots 92-92 extends from'the enlarged circular portion of one of the keyhole shaped slots 84-84 to the enlarged circular portion of an adjacent one of the keyhole shaped slots 86-86. The diagonal slots 92-92 are parallel to each other, and if they were projected beyond the keyhole. shaped slots which they connect, they would intersect the sides of the segmental plate 72 at an angle of about 45.

The diagonal slots 93-93 also extend in a parallel pattern which is nearly perpendicular to but does not actually intersect the parallel pattern of the diagonal slots 92-92. The diagonal 'slots'93-93 extend across the entire width of the segmental plate'72 and intersect the longitudinal sides thereof at an angle of about 50. Each of the diagonal slots 93-93 passes through the enlarged circular portion of one of the keyhole shaped slots 84-84 and also through the enlarged circular portion of one of the keyhole shaped slots 86-86. 50 specified herein are dictated by the geometrical arrangement of the terminal posts. Thus, each of'the terminal posts 54-54-and 56-56 extends through one of the segments 90-90 of the plate 72, and is separated The angles 45 and a by the diagonal slots 92-92 and 93-93 therein from all of the other terminal posts.

The enlarged circular portions of the keyhole shaped slots 80-80, 82-82, 84-84, 86-86 and 8888 facilitate the operation of mounting each shell 52 onto one of the composite plates 50-50. One of a plurality of nuts 94-94 is already loosely threaded onto each one of the terminal posts 54-54 and 56-56 at the time the shell 52 is brought into engagement with its composite plate 50. As the terminal posts are inserted through the keyhole shaped slots, the nuts 94-94 readily pass through the enlarged circular portions of the slots. After the nuts 94-94 have passed entirely through the slots in the upper plate 70, the intermediate insulating layer 74, and through the lower plate 72 of the composite plate 50, the shell 52 is slid to the right, as viewed in Fig. 1, until the nuts are positioned beneath the straight portions of the keyhole shaped slots, as shown in Figs. 3 and 4. The nuts are then tightened to secure the shell 52 firmly in place on the composite plate 50.

In one commercial embodiment of the invention, both the metal plate 70 and the segmental metal plate 72 are approximately 18 /2 inches long, from 1 /2 to 2 /2 inches wide, and about inch thick. Each of the two plates 70 and 72 contains a total of twenty of the keyhole shaped slots. In both of the metal plates the enlarged circular portions of the slots have a radius of about inch. The straight portions of the slots terminate in rounded portions each having a radius of about .281 inch in the upper plate 70, while in the lower plate 72 the corresponding rounded ends of the straight portions have a radius of about .096 inch. The thickness of the intermediate layer 74 of insulation was a very small fraction of an inch, so that this layer resembled a thin membrane.

As shown in greater detail in Fig. 5, the layer 74 is composed of two sheets 96-96 of gauze fabric, such as cotton, which are impregnated and coated with rubber cement. This cement securely bonds the plate 70 to the segments 90-90 of the segmental plate 72, while the sheets 96-96 of cotton gauze prevent the metal plate 70 from making contact at any point with the segmental plate 72. The cotton gauze sheets 96-96 are an important safeguard due to the fact that the insulating layer 74- is so thin.

In this same commercial embodiment of the invention, the diagonal slots 92-92 and 93-93 were not cut in the lower plate 72 until after this plate had been bonded to the upper plate 70 by the intermediate layer 74. A commercially obtainable rubber cement known by the tradename Plastilok was employed. First, one coat of this cement was applied to one face of each of the two metal plates, in which the keyhole shaped slots had been previously stamped. Then, a sheet of cotton gauze was applied over the cement coat on both metal plates. Next, another coat of the rubber cement was applied over the gauze sheets. Both plates were then heated for thirty minutes at 190 F. The preheated coated faces of the plates were pressed together under 150 lbs. per sq in. pressure and heated at 400 F. for ten minutes. After the assembly had cooled, the diagonal slots 92-92 and 93-93 were cut in the plate 72 to create the segments 90-90 thereof. As the final step in the manufacture of the composite plates 50-50, the gauze sheets 96-96 and the rubber cement in the intermediate layer 74 were punctured to form the slots 8888 therein in alignment with the keyhole shaped slots in the plates 70 and 72. In the resultant assembly, the upper metal plate 70 gave adequate structural strength and rigidity, while the insulating layer 74 and the diagonal slots 92-92 and 93-93 electrically isolated the segments 90-90 of the lower plate 72 from each other.

Obvious variations may be made in the composite plate structure and in the method of making such structure, without departing from the spirit and the scope of the invention.

(iii

What is claimed is:

1. A composite plate for supporting cable terminals having a plurality of individual terminal posts While performing electrical tests thereon, which comprises a pair of generally coextensive metal plates mounted parallel and spaced closely to each other, each of said plates having a plurality of similar slots aligned and arranged in a pattern suitable to permit the individual terminal posts of a cable terminal to extend through the composite plate, the slots in one of said plates being slightly larger than the corresponding slots in the other plate so that the terminal posts extending through the aligned slots are prevented from electrically contacting the plate having the larger slots therein, the plate having the smaller slots being divided into a plurality of isolated segments to insulate the terminal posts from each other, and a layer of insulating material sandwiched between and bonded to the pair of metal plates.

2. A composite plate for supporting cable terminals having a plurality of individual terminal posts while performing electrical tests thereon, which comprises a pair 'of generally coextensive steel plates mounted parallel and spaced closely to each other, each of said plates having a plurality of keyhole shaped slots aligned and arranged in a pattern suitable to permit the individual terminal posts of a cable terminal to extend through the composite plate, the slots in one of said plates being slightly larger than the corresponding slots in the other plate so that the terminal posts extending through the aligned slots are prevented from electrically contacting the plate having the larger slots therein, the plate having the smaller slots being divided into a plurality of isolated segments to insulate the terminal posts from each other, and a thin layer of insulating material sandwiched between and bonded to the pair of steel plates, said insulating material comprising at least one sheet of fabric gauze impregnated and coated with rubber cement.

3. A composite plate for supporting cable terminals having a plurality of individual terminal posts while performing electrical tests thereon, which comprises a pair of generally coextensive metal plates mounted parallel and spaced closely to each other, both of said plates having a plurality of keyhole shaped slots each of which slots includes an enlarged circular portion communicating with a short straight portion which terminates in a rounded portion, the enlarged circular portions of the slots in the two plates being aligned and arranged in a pattern suitable for the individual terminal posts of a cable terminal to extend through the composite plate, the straight portions of the slots in one of said plates being slightly larger than the corresponding portions of the slots in the other plate so that the terminal posts extending through the aligned slots are prevented from electrically contacting the plate having the larger slots therein, the plate having the smaller keyhole shaped slots therein being divided into a plurality of isolated segments by a plurality of diagonal slots which interconnect the keyhole shaped slots and extend to the outer edges of this plate, thereby preventing any of the terminal postsfrom being electrically connected to each other through this plate, and a layer comprising rubber sandwiched between and bonded to the pair of metal plates.

4. A composite plate for supporting cable terminals having a plurality of individual terminal posts while performing electrical tests thereon, which comprises a pair of generally coextensive metal plates mounted parallel and spaced closely to each other, both of said plates having a plurality of keyhole shaped slots each of which slots includes an enlarged circular portion communicating with a short straight portion which terminates in a rounded portion, the enlarged circular portions of the slots being aligned in the two plates and being arranged in a pattern suitable for the individual terminal posts of a cable terminal to extend through the composite plate, the straight portions of the slots in one of said plates '7 being slightly larger than the corresponding portions of the-slots .in the,otherplate so that the terminal .posts extending .through thealigned slots are prevented from electrically contacting the plate having the larger slots therein, the plate having the smaller keyhole shaped slots therein being provided with a plurality of diagonal slots which interconnect the keyhole shaped slots and extend -to the outer edges of this plate, thereby preventing any of the terminal. posts from being electrically connected to each other through'this plate, and a thin layer of insulating .material sandwiched between the pair of steel .plates to insulate them from each other and to bond them together, said insulating material comprising. at least one sheet of cotton gauze impregnated and coated with a heat cured rubber cement.

5. The method of making plates designed to support cable terminals which have a plurality of individual terminal posts protruding therefrom, which comprises the steps of stamping a plurality of slots in a metal plate in a pattern designed to receive the individual terminal posts of a cable terminal, stamping in another metal plate a plurality of slightly larger slots arranged in a similar pattern, placing the plates side by side with the slots therein in alignment, bonding the plates together with an intermediate layer of insulating cement, and cutting a series of diagonal slots in the plate having the smaller slots to divide this plate into a plurality of isolated segments each of which receives one of the individual termi- ,nal posts and insulates them from each other.

6. The method of making plates designed to support cable terminals which have a plurality of individual terminal posts protruding therefrom, which comprises the steps of stamping aplurality of generally keyhole shaped slots in a metal plate in a pattern designed to receive the individual terminal posts of a cable terminal, stamping in another metal plate a plurality of slightly larger generally keyhole shaped slots arranged in a similar pattern, placing the plates side by side with the slots therein in alignment, bonding the plates together with an intermediate layer of rubber cement, and cutting a series of parallel diagonal slots in the plate having the smaller keyhole shaped. slots to interconnect the. keyhole shaped slots therein anddivide this plate into a plurality .of isolated segments. each of which receives one of the individual terminal posts and insulates them from each other.

7. The method of making plates designed to support cable terminals which have a plurality of individual terminal posts protruding therefrom, which comprises the steps of stamping a plurality of generally keyhole shaped slots in a metal plate in a pattern designed to receive the individual terminal posts of a cable terminal,

7 stamping in a similar metal plate a plurality of slightly larger generally keyhole shaped slots arranged in a similar pattern, coating one face of .each of the two plates with a layer of a heat curable rubber cement, applying atleast one sheet of cotton gauze to each of the cement coatings, placing the coated faces of the plates together with their keyhole shaped slots in alignment, heating the plates while pressing them together under pressure until the cement is cured, and .cutting a series of parallel diagonal slots in the plate having the smaller keyhole shaped slots therein to interconnect the keyhole shaped slots and divide this plate into a plurality of isolated segments each of which receives one of the individual terminal posts and insulates them from each other.

References Cited in the file of this patent UNITED STATES PATENTS 249,574 Blake Nov. 15, 1881 2,006,436 Bowers July 2, 1935 2,087,311 Wensley July 20, 1937 2,390,863 Amidon et al. Dec. 11, 1945 2,423,869 Blessing July 15, 1947 2,442,984 Paris June 8, 1948 2,559,715 Earle et a1. July 10, 1951

Claims (1)

1. 2. A COMPOSITE PLATE FOR SUPPORTING CABLE TERMINALS HAVING A PLURALITY OF INDIVIDUAL TERMINAL POSTS WHILE PERFORMING ELECTRICAL TESTS THEREON, WHICH COMPRISES A PAIR OF GENERALLY COEXTENSIVE STEEL PLATES MOUNTED PARALLEL AND SPACED CLOSELY TO EACH OTHER, EACH OF SAID PLATES HAVING A PLURALITY OF KEYHOLE SHAPED SLOTS ALIGNED AND ARRANGED IN A PATTERN SUITABLE TO PERMIT THE INDIVIDUAL TERMINAL POSTS OF A CABLE TERMINAL TO EXTEND THROUGH THE COMPOSITE PLATE, THE SLOTS IN ONE OF SAID PLATES BEING SLIGHTLY LARGER THAN THE CORRESPONDING SLOTS IN THE OTHER PLATE SO THAT THE TERMINAL POSTS EXTENDING THROUGH THE ALIGNED SLOTS ARE PREVENTED FROM ELECTRICALLY CONNECTING THE PLATE HAVING THE LARGER SLOTS THEREIN, THE PLATE HAVING THE SMALL SLOTS BEING DIVIDED INTO A PLURALITY OF ISOLATED SEGMENTS TO INSULATE THE TERMINAL POSTS FROM EACH OTHER, AND A THIN LAYER OF UNSULATING MATERIAL SANDWICHED BETWEEN AND BONDED TO THE PAIR OF STEEL PLATES, SAID INSULATING MATERIAL COMPRISING AT LEAST ONE SHEET OF FABRIC GAUZE IMPREGNATED AND COATED WITH RUBBER CEMENT.

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