US2354907A - Electric switch - Google Patents

Description

Aug. 1, 1944. R. s. BENNETT ETAL ELECTRIC SWITCH Filed April 18, 1942 Inventors 5R?! gennet I e: by y ithJr;

Their ttorney.

U N 'lTZEsD STATES PATENT OFFICE ELECTBIC'SWITCH Ralph S. Bennettand SidnqB-Smith, In, Pittsfield, RIMS-y assignors to General Electric Company, a corporation .of'New lock Application April 18,1942, Serial No. 439,506

.12 (Johns (Cl. 200-133) omy and safety, it is 'desirable to locate the switch and fuse combined with it nearthe top of thepole adjacent the transmission .line. "The opening and closing of .the switch maybe'accomplished bya long switch stick with a hook adapted to engage the switch handle. However, ex-

amination of the fuse to determine whether or .not it-is operative and replacement of the fusible element is hazardous due. to the close proximity of the vlive switch contact and thetransmission line. Combined switches and fuses have been provided with an arrangement for automatically opening the switch when the fuse operates. 'lln this manner, the operation of the fuse isclearly indicated without the necessity of a close examination. Usually the supporting means for the combined fuse and line switch provides a place where birds, for example, can alight and. since the supporting means is often grounded, it is desirable to provide an arrangement in which there is substantially no possibility of contact being .made between the live partsof the combined fuse and switch and the supporting means as by a foreign object suchas a bird.

Accordingly, it is an object of our invention to provide a new and improved .birdproof switch in which the possibility of a bird, for example, standing upon the supporting means of the switch and engaging live parts of the apparatus is relatively remote.

It is. another object of our invention to provide a combined switchand fuse device having anew and improved arrangement, of terminal contact connections.

Still another object of our invention is to provide a new and improved supporting hanger for an electric switch of the type disclosedin" the above-mentioned patents.

Further objects and advantages of .ourxinvention will become apparent as the following :description proceeds and the features of novelty which characterize our invention will bepointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of our invention, reference maybe had to the accompanying drawing in which Fig. l is a side elevational view of our combined switch and fuse device, Fig. .2 is a view .taken on line 2- 2 of Fig. .1, 3 isa sectional view taken on .line 3-3 of Fig. 1, Fig. 4

. convenience might result.

supporting means therefor,..l'iig. 5 is an exploded view of I the new and improved nrpporting strap or hanger construction, and Fig. 6 is. a support- -.ing arm foranauxiliary expulsion protector tube or surgearrester, such as is disclosed in the cog application of Sidney R. Smith, Jr., SerialLNo. 439,507, filed concurrently with the present application which is adapted to cooperate with "the supporting strap or hanger construction of Fig. 5.

Referring :now to the drawing, we have illustrated an insulator ll which maybe suitably supported from a pole carrying the transmission line, not shown, as by asupporting strap, mount- ;ing bracket or hanger construction generally indicated at H, which is adapted to surround a central :portion of reduced diameter I! of the insulatori-ll. The details of the supporting strap or hanger construction, shown best in Fig. 5, will be set forth hereinafter in connection with the disclosures of Figab and 6.

vIt will be obviousfrom Fig. 1 that, if any live parts of the combined fuse and switch can be contacted .by a bird, for example, sitting on supporting strap II which is usuallygrounded. a short circuit with its consequent damage and in- Accordingly, the upper and lower terminal contact assemblies, generally :indicated at l3 and I4, respectively, are supported from insulator il in such a manner as toxprovide the greatest electrical clearance with respect to the supporting strap or hanger construction, generally indicated at i i, thereby proriding a birdproof construction. The. upper terminal assembly 0i: includes a looped conducting rod or wire 15 of a particular configuration to act as a contacts contact latch, and a contact guide as will become apparent from'the following description. The terminal assembly II, on the other hand, includes a looped conducting rod'or wire II which supports the lower contact constructioniof the switch to be describedin greater detail hereinafter. The means for "supporting looped rods .li'and l'l from insulator it which form one feature of our invention are substantially identical and, consequently, only one of these means will .be described-and the corresponding parts of the other supporting means will :be. designated by the same reference numerals.

The simplified means .of attachinglooped conducting rod I! to the lower end of insulator i0; -,which also provides simple means for attaching a lead-in wire or conductor ll thereto, cornprises a member having an irregularlyshaped .portion and an. outwardly-extending threaded portion such, for example, as a standard bolt i9 threadedwat one end and having a hexagonal head I! at the otherend. bolt ll isadapted to be anchoredin a recess in the end of is an exploded view ofthe terminal assembly and 60 insulator II as :by any .suitable means, such as cement 22, indicated in Fig. 3. With this arrangement, the head 20 of bolt I3 serves to prevent any motion tending to pull the terminal assembly I4 away from insulator III. A rectangular member such as a special square nut 23, (see Fig. 4) is provided for bolt I5 having an extending portion 23 which is preferably knurled. The knurled extending portion 23 is partially embedded in the cement 22 as indicated in Fig. 1. thereby preventing any rotation of the terminal assembly I4. Bolt I9 and nut 23 might comprise a single member having a rectangular portion, an irregularly shaped portion and an outwardly extending threaded portion. Square nut 23 acts as a guide for U-shaped washer 24 which extends down over the square sides. In the case of lower terminal contact assembly l4, the looped end of conducting rod I1 is clamped between square nut 23 and U-shaped washer 24 by means of a round or annular nut 25 of conducting material including a recess 26 therein for accommodating lockwasher 21 which, being preferably constructed of steel, affords a relatively poor conductor. By providing the recessed construction of round nut 25, a. good current-conducting path is afforded and the lock washer 21 of poor conducting material is bypassed. The nut 25 is preferably constructed in the annular form shown so that it cannot be readily loosened when connecting or disconnecting the lead wire or conductor I4 and also so that it cannot readily be tampered with. With the arrangement just described, the looped end of conducting rod I1 is tightly clamped between U-shaped washer '24 and square nut 23 with the lock washer 21 in recess 24 being sumciently compressed to provide the necessary looking action without interfering with the current conduction from nut 25 to rod I1.

The conductor or lead-in wire I4 is readily attached to the free end of bolt I! by being clamped between round nut 25 and multipronged washer 28 which is shaped so as readily to admit the insertion of lead-in wire I8. Suitable means including nut 29 and lock washer 30 are provided to fasten lead wire I5 and it will be observed that lead wire I8 may be connected or disconnected without in any way affecting or disturbing looped conducting rod I1.

As was mentioned above, the upper terminal assembly I3 for supporting looped conducting rod I5 is identical with lower terminal assembly I4 and also provides the same means for fastening a suitable lead-in conductor 3| thereto without disturbing the support of conducting rod II.

In order electrically to interconnect terminal assemblies I3 and I4, we provide a switch 32 including a fuse holder 33 within which is mounted the conventional fuse link, only the flexible cable portion 34' of which is shown in Figs. 1 and 2. The upper end of the fuse holder 33 is closed by a contact cap 35, which is threadedly mounted on a conducting upper contact member 34 having welded thereto a short conducting bar 31. The closed end of looped conducting rod I5 isfiared out as indicated at I5 to act as a contact guide for the upper fuse or switch contact 34 and a bent portion on each side of the loop acting as a contact latch I5" is provided suitably to engage the extending portions of rod 31 on either side of upper contact 36 to latch the switch in the closed position. Looped conducting rod I5 is of springy construction so as to tend to push downwardly on switch 32, thereby providing a good contact and also maintaining contact latch I!" in 75 latching position as long as the lower end of the switch is held in a fixed position, thereby preventing rotation of switch 32 to the open position. A suitable operating handle 34 is secured to fuse holder 33 adjacent contact 34 as by means of screw 33.

Switch 32 is pivotally mounted to the lower terminal assembly I4 by means of a toggle comprising toggle lever 44 and fuse holder support 4| pivotally connected at 42. Fuse holder support 4| surrounds the lower end of fuse holder 33. The flexible cable portion 34 of the fuse link extending from the lower end of the fuse holder 33 is adapted to be connected to toggle lever 44 as by means of thumbscrew 43. When the fuse link is intact, the toggle comprising the lever 44 and fuse holder support 4| is held in theposition shown in Fig. 1 by the flexible cable portion 34 of the fuse link. being tightly drawn and held by thumbscrew 43. In this position, toggle lever 40 has a projection 44 thereof engaging fuse holder support 4| to limit the relative movement therebetween.

In order pivotally to support switch 32 from terminal assembly I4, toggle lever 44 is provided with a hook-shaped portion 44 which is adapted to engage a sleeve 44 into which the ends II of looped conducting rod I1 are adapted to be inserted. These ends l1 are turned inwardly to readily engage sleeve 44, thereby forming a pivot for switch 32. In order to prevent lateral movement of toggle lever 44 pivotally mounted to sleeve 44, we provide side plates 41 which are secured to sleeve 44. To prevent rotation thereof, side plates 41 have notched out portions 44 to engage conducting rod I1. Also side plates 41 are provided with lanced out portions 45, which act as backstops for toggle lever 40 which is shaped as a cam at 44 to cooperate with these stops and prevent separation of the pivoted members comprising sleeve 44 and the hooked portion 45 of toggle 44 when the fuse is in the closed position. While the fuse link is intact, the switch 32 may be manually opened or closed in the usual manner by a switch stick provided with a hook adapted to engage operating handle 34. The opening movement of switch 32 is limited by the engagement of projections 44 extending from the sides of toggle lever 44 with side or hinge plates 41.

In order that the fuse link and fuse holder 33 may be replaced, it is desirable that ready removal of switch 32 from supporting insulator I4 may be accomplished as by means of a switch stick and, to this end, lever 43 is removably hooked to sleeve 44. However, the expulsion of gases from the lower end of fuse holder 33 upon blowing of the fuse link causes a recoil action which might permit unhooking of the hooked portion 45 of toggle lever 40 from sleeve 44 while switch 32 is rotating to the open position which would result in switch 32 falling to the ground. To prevent such unhooking, we provide a latch 5| pivotally connected at 52 to fuse holder support 4|. Suitable guides 53 and 54 are provided on toggle lever 44 between which the latch 5| is adapted to pass. During the opening movement of switch 32 upon blowing of the fuse link, the relative movement of toggle lever 40 and fuse holder support 4| will cause latch 5| to move between guides 53 and 54 in a downward direction as viewed from Fig. 1 so as to close the open portion of the hook 45 and thus prevent removal of toggle member 44 from sleeve 44. This latch feature and the lower switch support is not our invention but is disclosed and claimed in the above-mentioned Patent 1,973,265. Normally, when the switch is in the fully open position and the recoil forces are no longer acting on fuse holder 83, the relative positions of toggle lever 40 and latch 4| are the same as shown in Fig. 1, whereby the switch 82 may readily be lifted from terminal assembly I, by means of a switchv stick which engages operating handle 38, for replacement of the blown fuse link in fuse holder 33.

Upon operation of the fuse, the lower end of the fuse link including flexible cable portion 34 is expelled by the gas pressure generated by the arcing in fuse holder 33 and the support for toggle lever 40 is removed causing it to rotate about sleeve 46 acting as a pivot. However, the other lever of the toggle, namely, fuse holder support 6|, does not immediately follow rotation of toggle lever Mi due to the reaction produced by the rapid expulsion of the arc gases from the lower end of fuse holder 33. Shortly after the movement of toggle lever 40, however, fuse holder ll begins longitudinal movement produced by the spring action of upper looped conducting rod II pushing downwardly on rod 31. The longitudinal movement of fuse holder 31 is, of course, still opposed by the reaction of the gases being expelled from the lower end of fuse holder 33, but this reaction diminishes rapidly as the arc is extinguished and the expulsion of gases ceases. Shortly thereafter, the contact latch portions ll of conducting rod I! release rod I1 and switch 12 rotates about pivot 41 until engagement with toggle 40 results to limit the opening movement.

The conducting strap or hanger construction indicated at ii is best shown in Fig. 5 and comprises a support 56 having welded thereto two identical arms 51 having cooperating portions '1 for engaging with the reduced central portion I! of insulator ill. The support portion 50 is adapted to be bolted or clamped to a suitable pole or crossarm in an obvious manner. The ends of arms 51 are shaped in such a manner as to engage with U-shaped clamping member ll. U-shaped clamp it prevents spreading of the ends of arms 51 and is held in engagement therewith by means of bolt 5!, nut Cl, and lockwasher 6|. Clamping action to hold insulator ll firmly in supporting strap II is accomplished by means of bolt 6i and nut 82 adapted to be inserted in opening 03 in arms 51.

As is disclosed in the copending application of Sidney R. Smith, Jr., referred to above, auxiliary expulsion protector tubes or surge arresters are often utilized with switching devices similar to the one described heretofore in order to give protection against lightning surges and the like, which arrangement provides an arc gap between one of the terminal assemblies, such as terminal assembly i3, and ground. Since supporting strap or hanger construction II is usually grounded as at bolt SI for example the hanger construction ll illustrated in Fig. 5 is readily adaptable to being used with such an expulsion protector device and, accordingly, in Fig. 6, we have shown a conducting support 8| having a double U- shaped end 85 which is adapted to serve in exactly the same manner as U-shaped washer I. At the same time, an expulsion protector tube, only a portion of which is shown at I, is adapted to be supported so as to provide a spark gap between supporting strap i I and terminal assembly II. with the new and improved hanger construction of our invention, the switching device is readily adapted for use with or without such 76 an auxiliary spark gap for lightning protection of the expulsion protected tube type. It will be observed also that with the double U-shaped end the surge arrester may be supported either to the right or the left of insulator ll.

While we have shown and described our in- ,vention in considerable detail, wedo not wish to be limited to the exact arrangement shown but seek to cover in the appended claims all those modifications which fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

i. In an electric switch, an insulator, a stationary switch contactconsisting of a rod supporting a contact surface near one end, a standard bolt having the head thereof anchored in a recess at one end of said insulator, a square nut for said bolt having an extending portion thereof anchored in said recess, means including a U-shaped member cooperating with said square nut for securing the other end of said rod to said insulator so as to prevent rotation thereof, and means for securing a conductor to the free end of said bolt without releasing said rod during the operation of securing a conductor to said bolt.

2. In an electric switch, an insulator, a stationary switch contact consisting of a rod forming a contact surface near one end, a standard bolt having the head thereof cemented in a recess at one end of said insulator, a square nut for said bolt having a-knurled end embedded in the cement in said recess, means including a U-shaped member cooperating with said square nut for securing the other end of said rod to said insulator so as to prevent rotation thereof, and means for securing a conductor to the free end of said bolt without releasing said rod during the operation of securing a conductor tosaid bolt.

3. In an electric switch, an insulator, a ter-' minal assembly associated with each end of said insulator, and a switch member electrically interconnecting said terminal assemblies; each terminal assembly comprising a standard bolt having the head thereof cemented ina recess in an end of said insulator; a square nut including an extending portion, said extending portion being embedded in the cement in said recess, a rodlike member, means including a U-shaped member cooperating with said square nut for firmly fastening one end of said rodlike member to prevent rotation thereof, the other end of said rodlike member supporting a contact surface, and means for securing a conductor to the end of said bolt independently of said last-mentioned' means.

4. In an electric switch, an insuiator ,;a stationary switch contact consisting of a rod supporting a contact surface near one end, a standard bolt having the head thereof cemented in a recess at one end of said insulator, a square for said bolt having an extension embedded in the cement in said recess, a u-shaped member interengaging with said square nut for holding the other end of said rod against rotation, a nut having a recess therein for accommodating a lock washer of relatively poor conducting material for clamping said rod between said square nut and U-shaped member, and means for securing a conductor to the free end of said bolt by clamping it against said nut having a recess therein, whereby a very emcient electrical connection between said rod and said conductor is provided by effectively eliminating said lock washer from the electrical circuit.

5. In an electric switch, an insulator, a stationary switch contact consisting of a rod supporting a contact surface near one end, a standard bolt having the head thereof cemented in a recess at one end of said insulator, a square nut for said bolt having an extension embedded in the cement in said recess, a U-shaped member interengaging with said square nut for holding the other end of said rod against rotation, a circular nut having a recess therein for accommodating a lock washer of relatively poor conducting material for clamping said rod between said squar nut and U- shaped member, and means including a multipronged washer for securing a conductor to the free end of said bolt by clamping it against said circular nut, whereby a very efllcient electrical connection between said rod and said conductor is provided by efl'ectively eliminating said lock washer from the electrical circuit.

6. In an electric switch, an insulator, a stationary switch contact consisting of a rod supporting a contact surface near one end, a member including a rectangular portion, an irregularly shaped portion and a threaded portion, means for anchoring said irregularly shaped portion of said member in a recess at one end of said insulator so that said threaded portion extends outwardly from said insulator and said rectangular portion is anchored against rotation, means including a U-shaped member cooperating with said rectangular portion of said member for securing the other end of said rod to said insulator so as to prevent rotation thereof, and means for securing a conductor to said threaded portion of said member without releasing said rod during the operation of securing a conductor to said member.

7. In an electric switch, an insulator, a terminal assembly associated with each end of said insulator, and a switch member electrically connecting said terminal assemblies; each terminal assembly comprising a member including a rectangular portion, an irregularly shaped portion, and a threaded portion, means for anchoring said irregularly shaped portion of said member in a recess at one end of said insulator so that said threaded portion extends outwardly from said insulator and said rectangular portion is anchored against rotation, a rodlike member, means including a U-shaped member cooperating with said rectangular portion of said member for firmly fastening one end of said rodlike member to prevent rotation thereof, the other end of said rodlike member supporting a contact surface, and means for securing a conductor to said threaded portion of said member independently of said last-mentioned means.

8. In an electric switch, an insulator, a station ary switch contact consisting of a rod supporting a contact surface near one end, a member including a rectangular portion, an irregularly shaped portion, and a threaded portion, having the irregularly shaped portion cemented in a recess at one end of said insulator so that said threaded portion extends outwardly from said insulator, said rectangular portion being partially embedded in the cemented recess so as to be anchored against rotation, a U-shaped member interengaging with said rectangular portion of said first-mentioned member for holding the other end of said rod against rotation, a nut having a recess therein for accommodating a lockwasher of relatively poor conducting material for engaging said threaded portion to clamp said rod between said rectangular portion of said firstmentioned member and said U-shaped member, and means for securing a conductor to the threaded portion of said first-mentioned member by clamping it against said nut having a recess therein, whereby a very emcient electrical connection between said rod and said conductor is provided by eflectively eliminating said lockwasher from the electrical circuit.

9. In an electric switch, an insulator, a rod having a contact guide, a contact surface, and a latch adjacent one end thereof, a member including a rectangular portion, an irregularly shaped portion and a threaded portion, means for anchoring said irregularly shaped portion of said member in a recess at one end of said insulator so that said threaded portion extends outwardly from said insulator and said rectangular portion is anchored against rotation, means including a U-shaped member cooperating with said rectangular portion of said member for securing the other end of said rod to said insulator so as to prevent rotation thereof, and means for securing a conductor to said threaded portion of said member without releasing said rod during the operation of securing a conductor to said member.

10. The combination with an electric switching device having an insulating support and a pair of spaced terminal contacts, means for supporting an electric switching element from said support and electrically connected between said contacts, a mounting bracket for said support comprising a split member for encircling said support, a U-shaped clamp adapted to interflt with the split end of said member, and means for fastenof spaced terminal contacts, means for supporting an electrical switching element from said support and electrically connected between said contacts, a mounting bracket for said support mounting bracket.

1?. The combination with an electric switching sulating sumort on said mounting bracket.

RALPH S. BENNEI'I. SIDNEY R. SMITH, Ja.

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