US2546810A - Tool for use in replacing insulators in switch banks - Google Patents

Description

F. A. AN DERSON March 27,1951

TOOL FOR USE IN REPLACING INSULATORS IN SWITCH BANKS Filed July 27, 1948 2 sheets-sheet 1 lA/VENTOR F: A. ANDERSON ATTORNEY March 27, 1951 F. A. ANDERSON TOOL FOR USE IN REPLACING INSULATORS IN SWITCH BANKS Filed July 27, 1948 2 Sheets-Sheet 2 lNl/ENTOR F .A. ANDERSON ATTORNEY one side or the'other of the pins l9.

of the type with which the tool herein described is particularly designed tobe used.

The tools shown in the drawings comprise a terminal-locating and clamping fixture and a terminal and insulator clamping device. The cating and clamping fixture comprises a base which is a segment of a disc of hard rubber or similar electrically non-conductive material, having a cut-out space 2| of substantially the same shape and size as the insulator shown in Fig. 11. The top surface of the base is channeled adjacent its circular periphery to receive a hard rubber terminal lock ring 22, having an L-shaped cross section, th base of the L being on the outside. The outer edge of the ring and the outside wall of the channel are slotted to receive a metal retaining ring 23; and a stop screw 24 holds the retaining ring in place. The base 20 has metal, locating pins l9 projecting upwardly through individual arcuate slots 25 in the horizontal rim of the lock ring 22, one pin for each terminal of a row attached to an insulator of the bank in which defective insulators are to be replaced. The lock ring may be moved in its circular channel with.

respect to the base, the movement being limited by the length of the vertical slots 25 through which the pins [9 project. There are notches in the inner rim of the lock ring opposite the vertical slots for receiving and clamping the soldering .ends of the terminals of a row attached to an insulator. The space between the notches takes on the appearance of teeth or posts 26 of T shape, the heads of the posts serving to lock the terminalsagainst the pins by moving the lock ring in one direction or the other depending upon whether the terminals lie in the notches on the Since the soldering ends of the terminals of adjacent levels of a switch bank are curved laterally in opposite directions to provide a greater separation 'between like positioned terminals, the movement of the lock ring allows the soldering ends of a row of terminals to be placed in these notches of the ring on one side or the other of the, pins I9 depending upon whether these ends of the rowof terminals in question curve to the right or the left. In Figs. 4 and 5 the soldering end of the terminals are shown curved to the left and are placed in the notches to the left of the pins [9. A look spring 21, fixed at its mid-point by a screw and nut 28 to the base 20, is adapted to engage either end of the lock ring as desired and to apply pressure to move the lock ring into one or the other of its extreme positions in which positions the terminals placed in the notches are locked against the pins [9 by the posts 26. The ends of the lock spring 21 normally rest against stops 29,

the one end of the spring or the other beingmoved into engagement withthe corresponding end of ring 22 when desired, as illustrated in Fig. 5. v

The middle or hub-like portion of the base 20 has sets of locating pins 3|, 32 set therein in position to locate the inner ends of the terminals of a row in normally spaced relation and further has a set of steel spring locking arms 33 set in a knob 30 of hard insulating material, the knob being rotatable through a small angle on a pivot pin or stud 34 set in the base 20, whereby all of the arms 33 may be moved into or out 0f engagement with the inner ends of. terminals having their outer or soldering ends positioned in the notches of lock ring 22. The movement of the knob 30 is limited by pin 3'! set into the base 23 so as to engage the ends of a slot 38 cut vertically in outer edge of knob 30, as shown particularly in Figs. 1 and 6. An extension 39 of the stud 34 is threaded above the knob 33 and a lock knob 40 with a threaded metal insert therein screws on to this extension. By turning the lock knob 40, a lock washer 42-is forced against the knob 30 and the knob 30 may thus be locked with its arms 33 in engagement with the inner ends of the terminals. A screw 43 prevents the lock knob 40 from being turned off from the threaded portion of stud 34. Two balls 35 are held in engagement with the lower surface of knob 30 by springs 36 positioned in recesses in the upper surface of base 20. There is a slight recess in the undersurface of knob 30 to seat one ball when arms 33 are in position to engage the inner ends of ter- 7 minals; and there is a like recess in required position to seat the other ball when arms 33 are out of engagement with the terminals. Insulator p0- sitioning lugs l6 are secured to the base 20 in position to engage the ends of an insulator as shown in Figs. 4 and 5. These lugs extend above the top surface of base 20 as shown in Fig. 3 so as to be able to engage the ends of an insulator which is attached to the upper surfaces of a row of terminals or to engage the ends of an insulator which is attached to the lower surfaces of terminals clamped in the tool. In Figs. 4 and 5 the insulator is shown under the terminals but in other cases the insulator may be on top. The ends of the lugs are rounded to facilitate the placing of the insulator against the terminals. In order to insure accurate positioning of the insulators radially two sets of positioning springs I? and I3 are provided, springs H being fastened to the hub portion of base 20 and springs [8 to the inner edge of the circular rim portion of the base as shown particularly in Fig. 7. It frequently happens that some or all of th terminals of a row become detached from the insulator which is to be replaced during removal of the insulator from the switch bank; and each of these loose terminals must be separately inserted in the locating and clamping fixture but with knob 49 not tightened down to cause springs 33 to exert maximum pressure on terminals that are properly located in the fixture. The insertion of loose terminals is facilitated in the device described by beveling the clamping portion of the springs 33 as shown in Fig. 6. A further feature in this respect is the use of two springs and followers not shown but similar to items 35 and 33 shown in Fig. 3, and like these items located in base 20 but in such position that they, together with items 35 and 36 and with the. action of springs 33 against any properly located terminals, tend to have a leveling effect so that a loose terminal can be more readily inserted under a spring 33 than would otherwise be the case. This leveling action is of considerable importance in that it permits the springs 33 to be made stiff enough to adequately hold terminals when properly clamped. I

The terminal and insulator clamp or clamping 5, device comprise a lower clamping plate 51; an upper-clamping plat'e'5'3 and three screws 57. (SeeFigs. 5, 6, 9 and 10.) The plate has a layer of soft rubber 52 or other suitable insulating material attached. to its upper surface and the plate-is'has a likeinsulating layer 54 attached to its lower surface; The plate 5! has two positioning pins '55 set in its upper surface in required position to "engage two of the holes of an insulator. The upper clamp plate has holes 56 in corresponding position into which the pins 55 project when an insulator and row of terminals are clamped togetherby the two plates 51 and 53, Each screw 51 is loosely but-permanently held attachment with plate 53 by the collar 58 *in'jrecess'tilj theknob '59 being -forcedonto the shank end of the screws extending upward through the plate 53. The plate 51 has threaded holes positioned to receive the screws- 51, whereby the plates 5l'and53 oan be screwed together to hold a new insulator in close engagement with the terminalswhile' liquid adhesive between the insulator and'terminals is drying, as hereinafter described;

'While the base of the locating and clamping fixture is shown in the drawings as being onepi'ece', it may be desirable to make the clamp assembly for the inner ends of the terminals separately and attach it to the remainder of the base 2Q. Various other mechanical expedients may be substituted for those shown. Forinstance, the inner ends of the terminals may be positioned by like shaped depressions in the edge of the hub sectionof base 20 in place of the pins 3| and 3 2.

1 Wheria defective insulator is to be replaced in one bank of a groupof switchesi'n which the terminals aremultiplied, the screws which hold the terminals and insulators ofthe bank as a unit are removed, the bank is broken openand. the

defective insulator with terminals attached is loosened from the bank pile up. The terminals, with the defective insulator attached, are placed in the base 20 with the soldering ends of the terminals inthe notches of lock ring 22 and the inner ends of the terminals positioned by the pins 3| and 32 as previously described and as illustrated in Fig. 4. One end of lock spring 21 is thereupon positioned to engage one end of the lock ring 22 and thereby shift the ring to lock the outer ends of'the terminals under the head of posts 26 and againstthe pins It! as shown in Fig. 5. The knob 30 is then turned so that the accurately positioned by lugs l6 and the two sets of positioning springs l1, l8. Thelower clamping plate 5| of the terminal and insulator clamping device is then placed below the terminals and insulator with pins 55extending through two of the holes in the insulator. The upper clamping plate 53 is then placed over the terminals and insulator with pins 55 extending into holes 56. After the knobs 59 are turned to screw the two clamping plates together, the lock knob of the locating and clamping fixture is loosened and knob 30 turned to disengage arms 33 and the "inner ends of the terminals; and the spring 2'! is disengaged from the end of lock ring 22 and the ring is moved to unlock theouter eiids of the terminals. Theterminal and clamping fixture with the terminals and insulator clamped therein is now removedfrom the terminal locating and clamping fixture which may now be used with another insulator and row of terminals. When the adhesive between the insulator and terminals has dried, the plate 53 is unscrewed from plate 5| and the insulator with attached terminals re'- moved and placed in proper position inthe bank.

-What isclaimedis:

1. A tool for use in replacing insulators in switch banks without disconnecting the bank wiring from the terminals attached to an insulator which isto be replaced, consisting of a terminal locating and clamping fixture and an insulator clampin fixture; said terminal. locating fixture comprising a base oi'hard rubber or similar insulating material, the shape of'said base'being a major segment of a circle having a cut-out space of the same shape as said insulators and only slightly larger in size, a terminal lock ring slidably channeled in the outer rim of said base having inverted T-shaped notches in its upper edge, one 'notchio'r each terminal to be clamped in said fixture, metal pins extending upwardly through vertical slots in saidring opposite and just outside of said notches so that the wiring ends of a row of terminals may be individually placed on one side or the other of thejnotches depending upon whether the terminals curve out-- wardly to the right or to the left, spring means: adapted to engage either end of the lock ring as,

' base to position the inner ends of .arow of terminals, retaining springs set ina knob of insulating material, one spring for each terminaLsaid knob having a limited, rotary movement to move the springs into and out of engagement with the upper surface of the inner ends of terminals placed in said notches and between said pins, and a locking knob and washer mounted on a screw set in the pivot pin of said first-mentioned knob adapted when turned to press against and thereby lock the first-mentioned knob and springs in terminal retaining position, lugs on said base in position to accurately confine the ends of an insulator placed over terminals locked in said fixture, and fiat springs fastened to said base and extending vertically adjacent the opposing edges of said cut-out section to further accurately confine an insulator with respect to'a clamped row of terminals; said insulator clamping device comprising a top plate and a bottom plate which screws loosely fixed in said upper plate positioned corresponding to the other holes through the insulator and to threaded holes in the lower plate for clamping the insulator and terminals between the plates; said insulator clamping fix- V ture and clamped insulator and terminals being sulating material, the shape of said base being a major segment of a circle having a cut-out space of the same shape as said insulators and only 7 slightly larger in size, a terminal lock ring slidab ly channeled in the outer rim of said base having inverted T-shaped notches in its upper edge,

7 one notch for each terminal to be clamped in said fixture, metal pins extending upwardly through vertical slots in said ring opposite and ust outside of said notches so that the wiring ends of a row of terminals may be individually placed on one side or 'the other of the notches depending upon whether the terminals curve to the right or to the left, spring means adapted to engage either'end of the lock ring as desired to move the 7 ring' to lock the terminals placed in said fixture between said pins and the one or the other side of the notches, metal pins set in the outer edge of the hub section of said base to localize the inner ends of a row of terminals, retaining springs set in a knob of insulating material, one spring for each terminal, said knob having a limited rotary movement to move the springs into and out of engagement with the upper surface of the inner ends of terminals placed in said notches and between said pins, and' a locking knob and washer mounted on a screw set in the pivot in of said first-mentioned knob adapted when turned to press against and thereby lock the first-mentioned 'knob and springs in terminal retainingposition,

8 fastened to said base and extending vertically adjacent the opposing edges of said cut-out section to further accurately confine an insulator with respect to a clamped row of terminals.

3.-A tool for use in replacing insulators in switch banks without disconnecting the bank wir ing from the terminals attached to the insulator to be replaced, comprising a unitary terminal locating and clamping fixture for clamping the terminals of a row in proper relative positions, said gfixture including insulating material for maintaining electrical separation between terminals while clamped therein and means .for

confining an insulator in proper position with respect to the clamped terminals, and a separate clamping fixture comprising two plates adapted to be positioned on opposite sides of said clamped terminals and insulator for clamping said terminals and insulator while adhesive therebetween is drying, said separate clamping fixture includinginsulating material for maintaining electrical separation between terminals clamped therein, the terminal locating and clamping fixture being arranged to release the terminals to permit the insulator clamping fixture and clamped insulator and terminals to be withdrawn.

FRED A. ANDERSON.

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

UNITED STATES PATENTS OTHER REFERENCES Websters New International Dictionary, 2nd ed., unabridged, 1947.

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