US2301462A - Disconnect switch - Google Patents

Description

Patented Nov. 10, 1942 William SchultaSouth Milwaukea and'Alwin G. Steinmayer, Milwaukee, -Wis., assignors to Line Material Company, Milwaukee, Wis., a. cor-.

poration of Delaware Original applicationw June 16, 1939', Serial No. 279,414. Divided, and this application May; 25', 1940, Serial No. 337,194 V i 8 Claims.

This invention relates to disconnect switches for use in electrical distribution systems anddesigned for mounting out-of-doors on transmission line poles. Such a switch is ordinarily enclosed within-a porcelain housing and has a door hinged at the top to provide access to the switch; and the opening and closing of the switch is generally accomplished by means of a non-conductive hooked pole manipulated by a, lineman who must climb the pole to get within reach of the switch. Because such switches frequently carry very heavy currents it is important that the contact pressures behigh; and due. to the fact that a, switch may remain closedcontinuously for long periods of time while subjected to corrosive atmospheres causing the cont-acts to oxidize and adhere,,it has been found desirable, especially on the larger switches, to provide, in conjunction with the switch blade, a' movementamplifying lever mechanism which will function to break open the contacts-Without requiring a greater amount of force than a lineman can easily exert while maintaining his balance on a pole.

Our present invention has to do with improvements in disconnect switches of the type above referred to and has two primary objects. One object is to, achieve a maximum degree of compactness whereby to reduce the. size and cost.

of the porcelain housing and Bakelite door, while at the same time proportionately reducing the weight and the size of the package required. for

shipping and the space required for storing. The second object is to provide a disconnect switch in which the operating. lever when in closed position, can be more easily seenv and reached by a lineman standing on apole beneath the switch-and frequently also far to.

one side of .the switch.

The prior art discloses several knife-blade switches having movement-amplifying levers carried by the main switch blades at the free extremities thereof and there is presently on the market a housed disconnect switch having amain switch blade and a movement-amplifying lever likewise mounted at the extreme free end of the main blade. But in order to construct a housed disconnect switch in that manner and realize a desirable amount of amplification while at the same time providing for adequately breaking the high pressure contacts, it is necessary to extend the housing upwardly or else resort to. a system. of compound levers which complicates and increases the cost of the structure.

Pursuant. to the above recited objects, our

improved disconnect switch is characterized by the inclusion of a simple movement-amplifying lever mechanism which is carried bythe switchblade and pivoted'thereto at a point midway of the lengthof the blade and remote from the upper'end ofthe housing; and said mechanism is capable of providing the necessary degree of amplification of movement to bring about easy disengagement of the contacts, as well as adequate initial separation. of' the contacts, thus ensuring'that" the lineman will be able to complete each switch-opening. operation without undue effort while at the same time maintaining proper separation between switch terminals and reducing the overall length of the housing.

A second feature of our invention consists in the provision of a switch operating arm which projects outwardly, from the interior of the switch-containing. porcelain box into a recess in the housing door and well: beyond the front edge of theporcelain boxso that when the door is open saidarm is completely and readily accessi bio and: can be engaged bya hooked'pole in the lineman is'hand with a maximum of convenience;

.yet when the dooris. closed the entire switch structure; including said arm isunder cover; This secondfeatureis applicable whether the disconnect switch is provided'with. a movment-amplifying lever mechanism or otherwise.

While the present invention contemplates, more especially; improvements in housed disconnect switches, itis usefully applicable also to unhoused switches; as will1be apparent from the description which follows.

The present application is a division of our copending' application, Serial Number 279,414, filed J une l6, 1939;.entitledQuick -break disconnect switches.

In the drawings:

Fig. 1 is a view in side elevation, partly in section, showing. a housed disconnect switch; embodying. "this invention.

Fig. 2is a view similar. toFig. 1 showing the switch-moved toward open position.

Like parts are identified by the same reference characters throughout the several Views.

The housing-for the switch comprises a box-like casting of insulating material, such as wet process porcelain; which is moulded to form a relatively thick rearwall I, a top. wall 2, side walls 3, and bottom wall 4 having a recess 5.

A door 6 made of'insulating material such as Bakelite, is pivotally mounted at its upper end adjacent; the top wall 2 within the recessed portion 1. The pivot for the door. may comprisev a pin 8 extending through the walls 3 and hub portion 9 on the door. Disposed on pin 8, at each end of hub portion 9, are a resilient friction plate I3 and pressure member coacting to resist pivotal movement of the door, thus providing means for retaining the door in open position extending horizontally from the housing as indicated in Fig. 2. The means for retaining the door in elevated position has not been shown in detail, since any suitable means may be provided for obtaining the desired result.

The rear wall I of the housing is provided with spaced terminal supports l5 and I5 anchored in recesses I! by means of cement or other desirable material I8 and with a switch-blade support I9 spaced from the support I6 and anchored in recess 23 by means of cement 2|. Secured to the outer face of the rear wall I by any desirable means, such as bolts 22 anchored in the wall, is a pivot plate 23 having its ends 24 bent angularly to coact with similar ends on the mounting strap 25. The corresponding ends of plate 23 and strap 25 are pivotally connected by means of bolts 26 and are normally held against relative pivotal movement by means of nuts 21. The strap 25 is provided with bolts 28 cooperating with other parts, not shown, for attaching the housing to a crossarm, not shown. Disposed between the terminal supports I5 and I5, is a barrier 29 which increases the leakage distance between the supports.

The side walls 3 of the housing are each provided with spaced holes, not shown, adjacent terminal members 3| and 32 for insertion of line wires, not shown, to be connected with the terminals in the manner hereafter more fully disclosed.

Terminal members 3| and 32 are identical and, as may be clearly seen in Fig. 2, each comprises a base 34 having a. contact plate or blade 35 normal thereto and extending along a central portion thereof, wing portions 36 at opposite sides of plates 35 and each having an aperture 31, clamping jaws 38 disposed on opposite sides of the plate 35 and spaced from adjacent wing portions 33, and spaced legs 33. As may be clearly seen in Fig. 2', each contact plate 35 is L-shaped to provide a narrower portion which serves as a camming surface more fully described hereinafter.

Terminal members 3| and 32 are loosely mounted on terminal supports l5 and I5, respectively, to obtain a full-floating effect permitting lateral and angular alignment thereof relative to the supports and with the switch blades subsequently more fully described. This mounting is secured by means of sleeves 4| which fit loosely in apertures' 31 in the terminal members. The sleeves are rigidly retained on supports I5 and I6 by means of bolts 42 which extend through the sleeves and are threaded into the supports.

The upper terminal member 3| is retained on the sleeves by means of a washer 44 and the head of the bolt 42. The length of each sleeve 4| is greater than the distance between the bases of legs 39 and faces of wing portions 36 on terminal member 3 I, thereby permitting movement of the member between washer 44 and support I5.

Lower terminal member 32 is secured to support I5 in a similar manner described with reference to upper terminal 3I. Disposed between terminal members 3| and 32 and supports I5 and I6 are rectangular arcuately bent plate springs 48, which serve to hold the members outwardly of the supports and. in contact with washers .44 and 41, respectively.

Mounted on each of the clamping jaws 38 is a movable clamp having an elongated opening 5| receiving jaw 38 and provided with a clampactuating bolt 52 extending into and lengthwise of opening 5| for actuating engagement with jaw 38. The bared ends of conductors, not shown, may be passed through the holes in sides 3 of the housing and inserted between the cooperative clamping surfaces on jaws 38 and clamps 50 and clamped thereby upon appropriate manipulation of bolts 52.

Terminal members 3| and 32 may, for convenience of description, be denominated fixed contact members to distinguish clearly from the switch-blade, which is a movable contact memher.

The switch blade comprises a pair of spaced, parallel, fiat bars 53 and 54 which are pivotally mounted at the lower end of the housing on a pivot bolt 55 which-extends through bars 53 and 54 and support I9, and is secured in such position by means of a nut 56 and lock nut 51. The upper ends of bars 53 and 54, as viewed in Figs. 1 and 2, are connected by a bolt 59 which extends through the bars and is held in position by means of a nut 60. Preferably, the nut 60 is secured in position by mutilating the threads on the bolt, and cupped washers 6| are provided to give a degree of resiliency and for maintaining the bars in high pressure engagement with the contact 35 on upper terminal member 3|.

Passing laterally through bars 53 and 54 at a point below the upper fixed terminal is a bolt 62 on which are mounted cupped washers 64 bearing against said bars under the influence of a nut 63 and the head of the bolt-said bolt, washers and nut serving to press bars 53 and 54 into yieldable, tight, frictional engagement with terminal contact member 35.

Below bolt 62, as viewed in Figs. 1 and 2, and above the contact 35 on the lower terminal member 32, is a bolt 65 which extends through bars 53 and 54. A nut 69 retains bolt 65 in position. This bolt serves to hold the bars in firm frictional engagement with contact 35 on lower terminal member 32.

Pivotally mounted on bolt 65 and between bars 53 and 54, is a switch-operating lever E3 of the first class having at its upper end a pull-push ring 7| extending from between the bars, a cam finger 12, and stop finger I3 engageable with a pin I4 which extends through bars 53 and 54 and is retained in position by means of a washer 15 and cotter pin 16.

A coil spring 18 positioned between bars 53 and 54 is engaged at one end with pin 14 and at the other end with the apertured lug on lever 70. This spring normally maintains lever 13 in the position shown in Fig. 1 and against bolt 62.

When it is desired to move the switch from closed position, shown in Fig. 1, door 6, which is provided with a recess 6A for receiving pull ring II, will be first moved to the position indicated in Fig. 2. Pull ring H on lever 10 will be engaged by a, suitable operating stick, not shown, and thereby pulled from between bars 53 and 54. As lever 10 is pulled in the manner indicated, cam finger 12 at the lower end thereof engages the portion 40 on lower terminal member 32. Pressure thus applied to member 32 will first cause said member to assume substantially the position shown in Fig. 2, and thereafter cause the switch blade to move outwardly about the pivot bolt 55 to the position shown in Fig. 2 where the switch is out of engagement with contact member 35 on upper. terminal member. 3.! When. theswitchz has; reached. substantially: the. position shown. in, Fig: 2,.stopi finger 13. on lever will engage pin,

It may benoted that as. the cam finger l2 is forcedagainst; portion. 40; terminal 32 is slightly rotated about the sleeve. mountings 4|, thereby breaking loose; anyv oxide coating. which. may have formed on the. parts and which tend to hold the contact blades 35. in rigid; relation with bars 53 and; It; may. also. be noted that the mechanical, advantage of. the lever allows. an operator to movethe switch. to open. circuit. position with a.

minimumof; effort.

When theswitch is in openposition, door 6 may be closed tov prevent accidental contact with the live, portions, in the housing-and to prevent small birds from attempting to rest on such portions.

In housed; disconnect. switches of the prior art the. movement-amplifying switch-operating means corresponding to lever "iii and cam finger i2ghave been placed at the. free extremity of the switch-,blade,projecting. upwardly therefromand, have, accordingly, required a. considerable upwardiextension ofthe housing in order to provide necessary. clearance. operating means down and: pivoting it at an intermediate. point on the. switch-blade, as herein illustrated and; described, we are able to efiect a substantial reduction in the length of the housing andjdoorwhile atthesametime incurring no sacrifice with respect. to effectiveness of the switcheoperating. means. Although a greater force isvrequired to openv the switch when that force is applied to the switch-blade at an intermediate point, as in our structure, instead of at the free extremity of the blade, the additional force requirementv is. ofisetor more than offset by the greater-leverageratio.which ismade possible, It willbeiobservedithat a smaller angular movementof lever '10 is required to disengage the contacts; thanwould be the case if the switchoperating means were moved up-to or toward the freerend of the switch blade.

In our switch structure, it willbe noted, ring ll is wellbelow the upper end of the housingwhich is-a.distinctconvenience to the lineman and very adequate leverage advantage obtains.

So. far asunhoused disconnect switches are concernedit'may be generally. immaterialwhether. the movement-amplifying lever-isconnected' tothe switch-blade at its extremity or atan intermediate point; but where conservation of overhead clearance space or limitation of overall lengthare material factors, our structure has a distinct advantage which is not limited to housed switches.

Another advantage in our switch structure, from the linemans point of View, is'that ring H projects beyond the front edge of the porcelain box. Thus, when thedoor is open, the lineman,

whornay be'standing-on the pole-.to one side and below the switch, has-no difiiculty in seeing the By moving the switchringand engaging itxiwitlrthe hoolc end: of. a:

I switch stick. While this may seem'llike.a-mihor.

feature, itisitnevertheless'a.thing: ofireal consequencewhen'; adverse conditionszohtain', such. as: darkness; and snow storms;

Weclaim:

1. In. a; disconnect switch; alhousing. having. an interior chamber-and: comprising; a. box made. of insulating material and having a. frontal. opening leading into-said: chamber, saidthousing. including adisplaceable door: for said opening, said door providing. access to. saidchamber, and switch structure. disposed. within said chamber; said switch structure comprising afixed contact member. disposed within andadjacent the upper end of said chamber, a switch-blade support disposed within and near'the-lower endof said chamber, a switch-blade hinged at one end to said support and having a free -end portion frictionally engageable with and disengageable from saidcontact member, upon said blade-being rotated about its hinged connection to said support, and switchoperating' means supported on a pivot carried'bysaid .blade at apoint remote fromsaidcontact member and intermediate said contact member and said switch-blade support when the switch isclosed, said switch-operating means including a camfinger normally-extending from said pivot toward said support and a leverarm normally extending from said pivot toward the free'endof said blade, the free end of said lever armbeing manually accessible whensaiddoor is open, and abutment meansagainst which said cam fingeris arranged to bear, said cam finger being rotatable aboutsaid pivot toefieot pressure engagement withsaidabutment means for prying said switchbladeout of engagement with said contact member,--rotation of said cam-:finger about said pivot being effected'inresponseto an-outwardlydirected pull appliedto said lever arm.

2. In a disconnect switch, a housing having an interior chamber and comprising a boxmade of insulating-material andhaving a frontal opening leading into said chamber, said housing including a displaceable door for-said opening; said door providing access to said chamber, and switch structure disposed within said chamber,, said switch structure comprising a fixed contact memberdisposedwithin andadjacentthe upper end of said-chamber, aswitch-blade support disposed wthin and maths lower'end of said chamber, a switch-blade hinged atone end to said support and having a -free end'portion frictionally engageablewith anddisengageable from said contact member, upon said blade-being rotated about its hinged-connection to said" support, and switchoperating means Supported on a pivot carried by said blade at apoint remote from said contact member and intermediatesaid contactmember sponse to an outwardly directed pul1 applied to said lever arm.

3. In a disconnect switch, a housing having an interior chamber and comprising a box made of insulating material and having a frontal opening leading into said chamber, said housing including a displaceable door for said opening, said door providing access to'saidchamber, and switch structure disposed within said chamber, said switch structurecomprising a fixed contact member disposed within and adjacent the upper end of said chamber, a switch-blade support disposed within and near the lower end of said chamber, a switch-blade hinged at one end to said support and having a free end portion frictionally engageable withv and disengageable from said contact member, upon said blade being rotated about its hinged connection to said support, and switchoperating means supported on a pivot carried by said bladeat a point remote from said contact member and intermediate, said contact member and said switch-blade support when the switch is closed, said switch-operating means including a cam finger normally extending from said pivot toward said support, and a lever arm normally extending from said pivot toward the free end of said blade, at least the free end portion of said lever arm extending outwardly from said switchblade and through said frontal opening, said free end portion being manually accessible when said door is open, said door having a rear recess toreceive and clear the outwardly extending free end portion of said lever arm, and abutment means situated rearwardly of said switch-blade and against which said cam fingeris arranged to bear, said cam finger being rotatable about said pivot in response to an outwardly directed pull applied to said lever arm to efiect pressure engagement with said abutment for prying said Switchblade out of engagement with said contact member. I

4. In a disconnect switch, a housing having an interior chamber and comprising a box made of insulating material and having a frontal opening leading into said chamber, said housing including a door-for said opening, said door being A;

hingedly connected at the top thereof to the top portion of said box, said door providing access to said chamber, and switch structure comprising a fixed contact member disposed within and adjacent the upper end of said chamber, a switchblade support disposed within and near the lower end of said chamber, a switch-blade hinged at one end to said support and having a free end portion frictionally engageable with and disengageablefrom said contact member, upon said blade being rotated about its hinged connection to said support, and switch-operating means supported on a pivot carried by said blade at a point remote from said contact member and intermediate said contact member and said switchblade support when the switch is closed, said switch-operating means including a relatively short cam finger normally extending from said pivot toward said switch-blade support, and a relatively long lever arm normally extending from said pivot toward the free end ofsaid blade, at least the free end portion of said lever arm extending outwardly from said switch-blade and through said frontal opening, said free end portion being manually accessible when said door is open, said door having a rear recess to receive and clear the outwardly extending free end portion of said lever arm, said recess being situated below the hinged top of said door, and abutment and against which said cam finger is arranged to bear, said cam finger being rotatable about said pivot, in response to an outwardly directed pull applied to said lever arm, to effect pressure engagement with said abutment means for prying said switch blade out of engagement with said contact member.

5. In a disconnect switch, a housing having an interior chamber and comprising a box made of insulating material and having a frontal opening leading into said chamber, said housing including a door for said opening, said door having a localized recess on the inner side thereof, and switch structure disposed within said chamber, said switch structure including a switchblade pivoted within the lower end of said chamber and projecting upwardly from its pivotal point when the switch is closed, and an arm carried by said blade and projecting outwardly therefrom through and beyond said frontal opening into said door recess when the switch and door are closed, the free end of said arm being remote from said blade and adapted for engagement by a switch stick for opening and closing the switch, the arrangement being such that the free end of said arms is readily accessible for opening the switch when said door is open.

6. In a disconnect switch, a fixed contact member, a switch-blade support remote from said fixed contact member, a switch-blade hinged to said support and operative to frictionally engage said contact member, said blade being rotatable about said support to make and break contact with said contact member, and switch-operating means carried by and pivotally connected to said blade at a pivotal point remote from said contact member and intermediate said contact member and said support when the switch is closed, said switch-operating means including a relatively long lever arm projecting normally in a direction generally toward the free end of said switchblade and also laterally therefrom, said switchoperating means also including a relatively short lever arm normally projecting from said pivotal point toward said support and operative in the nature of a cam to engage an abutment for prying said switch-blade out of engagement with said contact member, said lever arms being rotationally interconnected through said pivotal point whereby a force applied to the end of said longlever arm and directed away from said blade is transmitted in amplified magnitude to the end of said short lever arm and thence to said abutment in a direction effective to move said blade toward open position.

7. In a disconnect switch, a fixed contact member, a switch-blade support remote from said fixed contact member, a switch-blade hinged to said support and operative to frictionally engage said contact member, said blade being rotatable about said support to make and break contact with said contact member, a pivot carried by said switch-blade and located at a point intermediate said contact member and said support when the switch is closed, an element carried by said pivot and rotatable thereabout in a plane substantially parallel to the plane of rotation of said switch-blade, said element including a relatively long lever arm normally projecting from said pivot in a general direction toward the free end of said switch-blade, at least a portion of said lever arm normally projecting laterally from said switch-blade, said laterally projecting portion being adapted for switch-operating engagement means situated rearwardly of said switch-blade with a switch stick, said element also including a relatively short lever arm normally projecting from said pivot in a direction generally toward said support, an abutment against which said short lever arm bears, stop means for limiting the angle of rotation of said element, and a spring continuously urging said element toward its normal position, said element being operative in response to a force applied to the free end portion of said long lever arm in a plane and direction tending to rotate said element out of its normal position to convert said force into a force of amplified magnitude at the point of contact between said short lever arm and said abutment, said short lever arm and abutment being so corelated that the aforementioned amplified force tends to move said switch-blade out of engagement with said fixed contact member.

8. Electric switch structure comprising: a first fixed contact member, a switch-blade support remote from said first contact member, a second fixed contact member including an abutment, said second contact member being remote from said first contact member and disposed intermediately of said first contact member and said support, a switch-blade hinged at one end to said support and operative tospan and frictionally engage said contact members, said switch-blade being rotatable into and out of engagement with said contact members, a pivot carried by said switch blade at a point intermediate the ends thereof and near said second contact member, and switch-operating means carried by said blade and rotatable about said pivot, said switch-operating means including a cam finger extending from said pivot in a direction generally toward said support and operative to engage and press against said abutment in a direction adapted to pry said switch-blade out of engagement with said contact members, a relatively long lever arm connected with said cam finger through said pivot and extending from said pivot in a direction generally toward the free end of said switch-blade, the free end portion of said lever arm being manually accessible, and stop means for limiting the angle through which said switch-operating means is rotatable about said pivot.

WILLIAM O. SCHULTZ. ALWIN G. STEINMAYER.

Images