US2338524A - Method of making electrical terminal fixtures - Google Patents

Description

Jan. 4, 1944. R. H. M CABE METHOD OF MAKING ELECTRICAL TERMINAL FIXTURES 5;; Filed June 8, 1940 2 Sheets-Sheet 1 INVENTOR Fiussefi H. iT Cab Jan. 4, 1944. R MCCABE 25338524 METHOD OF MAKING ELECTRICAL TERMINALVFIXTURES Filed June 8, 1940 2 Sheets-Sheet 2 Fig. 7

INVENTOR ATTORNEYS Patented Jan. 4, 1944 Ma'mon OF MAKING ELECTRICAL TERMINAL FIXTURES Russell H. McCabe, Detroit, Mich., assignor to- Burroughs Adding Machine Company, Detroit, Micln, a corporation of Michigan Application June a, 1940, Serial No. 339,469 4 .l'ci. 1H9) zclnlnn.

The present invention relates to methods of making electrical terminal fixtures.

In electrically operated and controlled appliances and machines, considerable wiring is uti-.

lized, which requires a large number of electrical terminal fixtures, each of which must be adequately secured to the connecting wiring and der positively to prevent short circuits. Ordinarily, rubber and like materials are employed to insulate the connections between the terminal fixtures and the associated wiring.

While terminal fixtures utilizing insulation of the type described are reasonably satisfactory in general, they are entirely unsuited for use in certain types of machines, such as calculating machines, due to the deteriorating effects upon rubbet and like materials of oils and lubricants nor- I mally present .in the machines, and'of heat developed incident to operation of the machines.

Accordingly, it is an object of the present invention to provide an improved method of making an electrical terminal fixture, which is not iniuriously affected by being subjected to oils, inbricants and considerable heat, and which is especially suited for use in a machine, such as a calculating machine, wherein it is subjected to oil, lubricant and a high ambient temperature.

Another object of the invention is to providean improved method of making an electrical terminal fixture which requires a minimum number of simple and easily performed steps;

A further object of the invention is .to provide an improved method of making an electrical terminal fixture utilising a single heated die dels formed of a material consisting essentially of a cellulose ester'resin, such as "Tenite."

In accordance with another feature of the invention, the electrical terminal fixture is made in accordance with an improved method whichcor'nprises placing a preformed rigid, self-supporting tubular sleeve of a thermo-plastic insu-' thoroughly insulated from adjacent parts in orlating material in surrounding relationship with respect tothe bared portion of an electrical conductor having an insulating cover and the adjacent portion of the cover and the adjacent por tion of an electrical terminal secured to the bared portion of the cover, and then subjecting the sleeve to a heating'and deforming operation in order to mold the sleeve into intimate'contact with the bared portion of the conductor and the adjacent portions of. the cover and the terminal.

' More particularly, the sleeve, after being placed in surrounding relation with respect to the ele-,

ments of the terminal fixture mentioned, is positioned between a pair of complementary heated molding dies; the dies are then moved rapidly into firm engagement with the sleeve in order to heat the sleeve; and then the dies are forced gradually together in order to mold the sleeve into intimate contact with the bared portion of the conductor and the adjacent portions of the cover and the terminal.

The novel features 'believed' tobe characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and its method, together with further objects and advantages thereof, will best forming operationlfto apply an'insulating,em-

bedding and anchoring, body to certain elements of theterminal-fixtureq} ",In generalathe'obict's, asset. forth above, are in part attained accordance with the present invention by ron insanel ptrical terminal fixture comprising an-"electrical conductor having an insulating cover,- a portion of the conductor projecting from the eover, an electrical terminal connected to the projecting portion of the conductor and a body of rigid insulating material. More particularly, the body of insulating material is molded into embedding relationshipwith respect to the projecting portion of the conductor and the adjacent portions of the cover and the terminal and into interlocking relationship with respect to the adjacent portions of the cover and the terminal, whereby the connection between the projecting portion of the conductor and the terminal is thoroughly insulated and relieved of strain. The insulating body of the terminal'fixture is formed of a rigid, inactive, lubricant resistant, heat resistant, insulating material. Preferably, the insulating body of the terminal fixture be understood by reference to the following specification taken in connection with the acc'om-' panying drawings, in which Figure 1 in an exploded perspective view of a partially completedelectrical terminal fixture, which is made in accordance with the method of the present invention, and die apparatus which may be utilized in accordance with the method of the present invention, the die apparatus being shown in open position; Fig. 2 is a side eievational view. partly broken away, of the terminal fixture and the die apparatus shown 'in' Fig. 1, the die apparatus being shown in closed position; Figs. 3, 4 and 5 are fragmentary side elevational views of the terminal fixture, illustrating the various steps in the method of making the same; Fig. 6 is a fragmentary side elevatlonal view of'a machine press which may be utilized in conjunction with the die apparatus shown in' Figs. 1 and 2 in making the terminal fixture; and Fig. 7 is a schematic diagram of an electrical circuit for heating and for controlling the temperature of the die apparatus. Referring now more particularly to the drawings, in l 'lgs. 1 to 5, inclusive, there is illustrated an electrical terminal link ll carrying electrical terminal fixtures II on the opposite ends thereof, each of the terminal fixtures embodying the com struction and arrangement of, and bein made in accordance with the method of; the present invention. More particularly, the terminal link I comprises an electrical conductor I2 having an insulating cover I; of any suitable type, the cover It being illustrated as of the insulating fabric type. Portions a of the conductor I2 project from the opposite ends of thecover II and are suitably secured to associated electrical terminals l4, each of the terminals ll comprising an eyelet Ila adapted to receive an associated electrical connecting stud and a tail llb. More specifically, each projecting end portion Ila of the conductor I2 is secured to the tail llb of the associated terminal 14. Preferably, each projecting end portion l2a of the conductor l2 extends through an opening He provided in the tail llb of the associated'terminal H and is return bent, as indicated at [2b, in order positively mechanically to anchor the conductor II to the terminal ll. electrical connection between each end portion lid of the conductor I2 and the tail Nb of the associated terminal ll a suitable amount of fused:

portions of the cover It and the tail llb of the associated terminal I and into interlocking relationship with respect to the adjacent portions or the cover I! and the tail Nb of the associated terminal I.

More particularly, the body I! is formed of a hard, rigid, inactive, oil and lubricant resistant, and heat resistant insulating material, the body II being formed of hard insulating material in order positively to armor and thoroughly to insulate the connection between the projecting end portion lid of the conductor I2 and the tail llb of the associated terminal l4, and being formed of rigid material in order positively to relieve this connection of strain. Also, the, body II of the terminal fixture II is formed oi. inactive in-. sulating material containing no acid residue in order positively to prevent corrosion of the connection between the projecting end portion I241.

Preferably, the body II of the terminal fixture I l is formed of the thermo-plastic insulating material known as Tenite, this material having the properties mentioned above and consisting essentially of a cellulose ester resin, principally a cellulose acetate resin.

Referring now more particularly toFigs. 1, 2 and 6, there is illustrated die apparatus which may be utilized in making the terminal fixtures, this die apparatus comprising an upper movable die It provided with a supporting tail "a and a lower stationary die I! provided with a supporting tail I111. The lower die 11 comprises a body portion it having a molding cavity ll Further, in order to perfect the therein and two pairs of upstanding guide projections 20, 2| and 22, 2!; while the upper die I comprises a body portion 24 having a molding cavity 28 therein and a pair of guide faces 26 and 2l. The upper and lower dies It and H, respectively, are so constructed and arranged that the upper die I! is'adapted to be forced into engagement with the lower die ll; whereupon the respective body portions 24 and It thereof are brought into superimposedrelationship, thereby to form a composite molding cavity, including the complementary molding cavities 25 and 19 respectively provided in the body portions 24 and I. of the upper and lower dies ll and l1,

. thereby positively to insure proper alignment of the body portions 24 and "of the respective upper and lower dies I and I1.

Further, the pair of guide projections 20 and 2| carried by the lower die H are so constructed and arranged that a semicylindrical recess 28 is formed therebetween which is adapted to cooperate with a complementary semi-cylindrical recess 2! formed in the body portion 24 of the upper die it in order to provide complementary clamping jaws adapted to receive and firmly clamp the cover II of the conductor 12 when the upper die I Gis forced into engagement with the lower die ll. Similarly,'the pair of guide projections 22 and 23 carried by the lower die I! are so constructed and arranged that a' notch ll is formed therebetween which is adapted to cooperate with a complementary notch 3i formed in the body portion 24 of the upper die I! in order to provide complementary clamping jaws adapted to receive and firmly clamp the tail Nb of theiassociated terminal ll whenthe uppeddie it is forced into engagement with the lower die l'l.

Referring now more particularly to Fig. 6, there is illustrated a machine press which may be utilized in conjunction with the die apparatus including the upper and lower dies l6 and I1 in making the terminal fixture. More particularly, the machine press comprises a supporting frame 32 carrying a lower stationary die head 33 and an upper movable die head 34, the upper die head 34 being slidably mounted for reciprocating movement in the vertical direction upon a guide bar 35 carried by the supporting frame 32. The lower die head I! is provided with facility for mounting the supporting tail lla of the lower die ll; while the upper die head 34 is provided with facility for mounting the supporting tail lid of the upper die ii, whereby the upper die I6 ,is movably mounted in cooperating relationship with respect to the lower die H, in the manner previously explained. 7

As best shown in Figs. 6 and '7, an electrical circuit arrangement comprising two electrical heating elements 36 and 31 is provided for heating the upper and lower die heads 34 and 33, respectively, the heating element 38 being disposed in a suitable cavity 38 provided in the lower die head 33 and the heating element 31 being disposed in a suitable cavity 39 provided in the upper die head 34. Also, this circuit arrangement comprises two thermostatic switches 40 and 4| which are arranged in heat conducting relationship withrespect to the lower and upper die heads 33 and 34, respectively, in order to control the circuits for energizing the heatable clutch mechanism 55 arranged between the ing elements 36 and 31, respectively, thereby motor 54 and the drive shaft 46. Preferably, the positively to govern the temperature of the upclutch mechanism 55 is of the character of that per and lower dies l6 and I1 respectively cardisclosed and claimed in Theodore S. Bindschedrled by the upper and lower die heads'34 and 3t. 5 ler Patent No'. 1,658,036, issued February 7, 1928, Preferably, each of the thermostatic switches 40 I and comprises a trip shaft 56 and a trip lever 51, and 4! is independently adjustable, thereby to the trip lever 51 being pivotally mounted on a allow independentadjustment of the heat suppivot pin 58 carried by the supporting frame 32 plied to'each of the dies and consequently the and connected by a pin and slot arrangement temperature of each of the dies. Finally, this 59 to a lever 80 carried by the trip shaft 56. The circuit arrangement comprises a master switch trip shaft 55 is biased to a normal position by a 42 for controlling the circuits of both of the coil spring 81 extending between a pin 62'carheating elements 36 and 31, and a pair of cirried thereby and a pin 43 carried by the sup,- cuit conductors 43 connected to a suitable source porting frame 32, and is adapted to be tripped of current supply. by the operation of the trip lever 51. More par- Referring again to Fig. 6, the machine press ticularly, the trip shaft 56 is biased in a clockfurther comprises an operating bell crank 44 wise direction by the coil spring BI and is adapted pivotally mounted on a pivot pin 45 carried by to be rotated in a counterclockwise direction the supporting frame 32 and a drive shaft 48. 1 against the bias of the coil spring 4| when the The bell crank 44 comprises an arm 41 opera- 2o trip lever 51 is depressed in an obvious manner. tively associated with an adjustment screw 48 The clutch mechanism II is so connected and carried by the upper die head 34 and an arm 49 arranged that, when the trip shaft 56 is tripped,

carrying a pin 50 rotatably supporting a roller 5|, the drive shaft 46 is automatically clutched to the roller 5i cooperating with a cam 52 secured and subsequently declutched from the motor 54, to the drive shaft 46. Thebell crank 44 and the whereby the drive shaft 48 is rotated precisely cam 52 are so constructed and arranged that, one revolution.-

when the drive shaft 46 is rotated one revolution From the foregoing explanation of the mode of in a counterclockwise direction, the .cam 52 operation of the machine press, it will be underforces the cooperating roller 51, and consestood that each time the trip'lever I1 is dequently the arm 49 of the bull crank 44, abruptly pressed the trip shaft 56 is tripped, thereby to toward-the left and then gradually further tocause the drive shaft 46 to be clutched to the vward the left, and then ultimately allows the motor 54 and rotated one revolution in the counroller 5i, and consequently the arm 49 of the terclockwise direction; whereupon the upper die 4 above descri tion of the machine; ress it will be the coil spring as, when the-drive shaft is bell crank 44 to be forced abruptly toward the It is moved into closed position with respect to right back to'its normal position. As a consehe l wer d e n nd hen ved 170 p n P quence of this operation of'the cam-52' and cotion with respect thereto.

operating roller 5|, th bell rank 44 i ab- In making the electrical-terminal fixture in acruptiy rotated in the clockwise direction a precordance with the method of the present indetermined angular distance about the pivot ven n, th ducto l h vin he insulating pin 44 an'dthen gradually rotated in the clockcover I3 i firs provided and then a portion of wise direction a further angular distance about the insulating cover it is removed from the conthe pivot pin 45, and then ultimately abruptly ductor l2 adjacent one end thereof in any suitrotated in the counterclockwise direction about able manne in order to provide the bared prothe pivot pin back to its normal position. As i ctins end lid of the'conductor 42-, The red a result of this movement of the bell crank 44,. P j cting endiia of the condu w l 8 010N164 the arm 41 thereof engaging th adju tment; in any suitable manner and, linsertedthrough screw 48 moves the upper, diefihead 34'. rapidl and then gradually downwardly-towardthe lowe die head'33 against the bias ,of'acoil'spring-li' extending between theupper die head and th supporting frame 32; and subsequentlyigpermit the coil spring I3 tomove the uppei'idie head I rapidly upwardly away from the lower die has 33 back into its normal position. Inview. of th provided-terminal l4. subsecu'ently. the bared projecting .endflc of the conductor II is return the conductoril to the 44b oi'the terminal Further, the connection between the boredproiecting-end "a of the conductor i2 and the thrice-came terminal l4 is .reenforced by fused metal, such assolder or thelike, thereby further a reement connection-{and to insure a good understood hat,. due to the" co'nktructionli'and arrangement of the cam 51, the bellfcrankfljan p g theterminal l4,jy I 4 y rotated one revolution, the upper diellfiis-nrs -p f med O -D molded riI d Sleeve moved rapidly toward the'lower die H andizthe U forced gradually into engagement therewith; due H sulatirig material, which is subsequently deformed primarily to the configuration of the cam 52 yln order tq produce the insulating body II. is then and then subsequently rapidly returned to its, Dllc pon the pposite end of the cover II, in

bent upon itself in raer-- mechanically to secure ectrical bond between the conductor i l. and

fofqthe prevlously mentioned thermO-Dlastic 111- normally disengaged position with respect to the g th event at it s not P eviously placed lower die l1. due primarily to the provision of as thereupo -J M thi point itisnoted that.in makthe coil spring. 53. Further, in this connection; in! the electrical terminal link l-l comprising ter it is noted that the actual stroke of the upper minal fixtures ii on either end thereof, it isad. die s t and away from t 11 n jvisabletopiace two of the sleeves mentionedupon may be adjusted by adjusting the stroke of the the cover ll of the conductor it before securing upper die head 34 by means of the adjustment 0 the Oi positely projecting bared ends Ila of the screw 48, thereby to govern the mating 'ofthe" conductor 12 to the associated terminals M, in

upper and lower dies it and II, respectively, and Y the manner previouslyexplained. In any event, consequently the pressure exerted therebetween. at this time, the insulating sleeve surrounding the Finally, the machine press comprises a motor cover ll of the conductor i2 is slid longitudinally 54 adapted to operate continuously and suitalong the cover I! from a position, such .as indicated on the left-hand side of Fig. 3, to a position, such as indicated on the right-hand side of Fig. 3; whereby the sleeve is disposed in surrounding relationship with respect to the hated portion I20 of the conductor I2 and the adjacent portion of the cover I3 and the adjacent portion of the tail Ilb of the associated terminal I4.

After the insulating sleeve has been positioned with respect to the connection between the bared projecting end I2a. oi. the conductor I2 and the,

tail Nb of the terminal I4, the assembly is positioned in-the lower die. Il supported by the lower die head 33.0! the machine press, as'clearly shown in Fig.1. More particularly, at this time,-the insulating sleeve .is disposed in the open top of the molding cavity I9 provided in the body portion I8 of the lower die I1; the tall Ilb of the terminal I4 is positioned in the notch 30 disposed between the pair of upstanding guide projections 22 and 23 carried by the lower die I1;

and the portion of the cover I 3 adjacent the ba d projecting end Ila of the conductor I2 is positioned in the recess 28 disposed between the pair of upstanding guide projections 20 and 2I carried by the lower 'die Il. At this time, 'the insulating sleeve carried by the conductor I2 and positioned in the molding cavity I9 provided in the body portion I8 oi the lower die I! is in readiness to be acted upon by the upper and lower dies I6 and I1, respectively, thereby to mold the sleeve into the body I5 of the terminal fixture.

In order to accomplish molding of the sleeve mentioned into the body I5 of the terminal fixture II, the trip lever 51 of the machine press, shown in Fig. 6, is tripped in the manner previously explained; whereupon the upper'die I is moved rapidly towardthe lower die I! into firm engagement with the sleeve surrounding the conductor I2 in order to heat the sleeve. The upper die It is then forced gradually toward the lower die I I In order to continue the heating of the sleeve surrounding the conductor I 2 and to subject the sleeve to a deforming pressure, as clearly shown in Fig. 2. At this time, the cavity 25 pro vided in the body portion 24 of the upper die -I6 engages the upper surface of the sleeve surrounding the conductor I2; and thecavity I! provided in the body portion I8 of the lower die I! engages the lower surface of the sleeve sur- Furthermore, the.

rounding the conductor I2.

and II, respectively, molds the cylindrical sleeve into the smooth rounded body I of the terminal fixture II, as clearly shown in Figs. 2 and 5.

In connection with the molding or remoldin of the insulating sleeve into the body I5 of the terminal fixture II, it is noted that the tempera- 'tures of the upper and lower dies l6 and I1,

respectively, must be maintained so that the insulating sleeve is subjected, during the molding operation, to a temperature of the order of 300 '1". Further, it is pointed out that preformed insulating sleeves of Tenite" of suitable length may be acquired commercially or produced initiallyby a suitable molding operation utilizing "Tenite in powdered form.

Subsequently, the upper die I6 is moved away from the lower die II, in the manner previously explained; whereupon the finished terminal fixture I I is removed from the lower die I! and allowed to cool. When the body I! of the terminal fixture H has been allowed to cool, it sets or reassumes a hard, rigid condition and is ready for service.

While there has been described what is at present considered to be the preferred embodiment of the terminal fixture andi the method of making thesame in accordance with the present invention, it will'be understood" that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention. What is claimed is: l. The method of making an electrical insulated conductor terminal which comprises the steps of placing upon an electrical conductor, having an insulation covering and a bare conductor end portion, a sleeve of rigid therm0plastic insulating material and positioning said sleeve to surround an insulation-covered portion of said conductor, securing an electrical terminal means to said bared conductor end portion in electrical- 1y conducting relation therewith. moving said sleeve to a position in which it surrounds said bared conductor end portion, a portion of said insulation covering on said conductor adjacent portion of the tail b of the terminal 14 dis- I posed adjacent the projecting portion Ila of the conductor I2 is firmly clamped between the co-' operating notches 30 and 3| provided in the lower and upper dies I1 and I 6, respectively; while theportion of the cover I3 adjacent the projecting portion Ila of the conductor I2 is firmly clamped between the cooperating recesses 28 and 2! provided in the lower and upper dies I1 and II, re-

pectively. V i

As a result of the action of the upper-and lower dies I6 and II, respectively, the sleeve surrounding the conductor I2 is rendered plastic and is deformed and molded into intimate contact with the bared projecting portion I2a of the conductor I2, the adjacent portion of the cover I! and the adjacent portion of the tail Nb of the terminal I4, thereby to interlock the adjacent portion of the tail Nb of the terminal I4 and the ad- J'acent portion of the cover I3, after the body I! sets, in order to relieve of strain the connection between the projecting portion Ila of the conductor I2 and the tail Ilb of the terminal ll. Also, this action of the upper and lower dies I! said conductor end portion and a portion of said terminal means, and heating said sleeve and compressing it in molding means to mold said thermoplastic sleeve into intimate contact and solid engagement with at least said surrounded portions of said terminal and insulation covering.

, 2. The method of making an electrical insulated conductor terminal which comprises the steps of placingupon an electrical conductor,

. having an insulation covering and a bare conductor end portion, a sleeve of a rigid thermoplastic insulating material selected from the class comprising cellulose acetate and mixtures including cellulose acetate, positioning said sleeve to surround an insulation-covered portion of said conengagement with at least said surrounded-portions of said terminal and insulation covering.

RUSSELL H. MCCABE.

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