US2803726A - Hook stick operated disconnect switch - Google Patents

Description

Aug. 20, 1957 w. H. GILLILAND HOOK sncx OPERATED DISCONNECT swncu s Sheet s-Sheet 1 Filed June 3, 1954 INVENTOR Wauu ll. fiuuua ATTORNEYS -Aug. 20, 1957 w. H. GILLILAND 2,803,726

HOOK STICK OPERATED DISCONNEICT SWITCH Filed June 3, 1 954 3 Sheets-Sheet 2 INVENTOR W umn H Guuuwa BY W05 ATTORNEW 0, 1957 w. H. GILLILAND 2,803,726

HOOK sncx OPERATED msconuzcr swrrcu Filed June 3. 1954 3 Sheets-Sheet 3 INVENTOR Waunn bf fiuluua ATTORNEK United States Patent 01 HOOK STICK OPERATED DISCONNECT SWITCH William H. Gilliland, Birmingham, Ala., assignor to USCO Power Equipment Corporation, Birmingham, Ala., a corporation of Alabama Application June 3, 1954, Serial No. 434,257

14 Claims. (Cl. 200-162) This invention relates generally to electrical switching apparatus and more particularly to hook stick operated disconnect switches of the swingable blade type for engaging or disengaging fixed or stationary contact members for respectively making or breaking the electrical circuit.

It is an important object of this invention to provide a disconnect switch having a pair of parallel, transversely spaced switch blades hinged at one end with a contact member having transversely spaced contact edges disposed between the blades and adjacent the hinge to relieve the hinge of the duty of carrying the current passing through the blades.

It is a further important object of this invention to provide a disconnect switch having a pair of transversely spaced, parallel switch blades with longitudinally spaced upturned contact members disposed between the blades adjacent opposite ends thereof and having transversely spaced contact edges in engagement with the blades when the switch is closed.

It is another object of this invention to provide a disconnect switch having a pair of transversely spaced, parallel switch blades with an upturned contact member disposed between the blades adjacent the end thereof and having transversely spaced contact edges in engagement with the blades when the switch is closed and with transversely disposed guide member to guide the blades as they descend to closed position on to the contact edges.

It is a further object of this invention to provide a disconnect switch having a pair of transversely spaced and parallel switch blades hinged at one end with upturned contact members disposed between the blades adjacent opposite ends thereof and having transversely spaced contact edges in engagement with the blades when the switch is closed and with a wedge-shaped curved arm pivoted on the blades adjacent the other end and a pair of upstanding complementary wedge-shaped arms having surfaces cooperable with the curved arm to provide pry out means for opening the switch.

A still further object of the present invention resides in providing a hook stick operated disconnect switch having a pair of transversely spaced, parallel switch blades hinged at one end to an insulator supported hinge arm and longitudinally spaced, transversely extending insulator supported contact members disposed between the blades and providing oppositely outwardly facing contact edges with a blade contact guide at the free end contact longitudinally offset with respect to said contact edges whereby the point of intersection between the blade and the contact guide lies along an arcuate path removed from the normal line of contact between the blades and free end contact edges to thereby minimize frictional wear along the normal line of contact in the opening and closing of the switch.

Another object of the present invention resides in providing a hook stick operated disconnect switch having a pair of transversely spaced, parallel switch blades hinged at one end to an insulator supported contact clamp bracket for swinging movement to engage the other end with a spaced line contact with upturned line terminal contact elements fastened to respective spaced insulators by the aforesaid contact clamp bracket and a combined latch supporting, pry-out lug, clamp bracket with the upturned contact elements positioned to span the space between the switch blades inwardly between the clamp brackets.

A still further object of the present invention resides in providing a hook stick operated switch having a pair of transversely spaced, hinged, parallel switch blades and an insulator supported pivoted latch cooperating with a latch pin at the free ends of the blades with a latch releasing and pry-out means in the form of a pivoted hook stick receiving ring pivotally mounted on the latch pin and having a pair of angularly related arms for respectively camming the latch to released position and providing a leverage advantage for comming the switch blades out of closed switch position.

Still another object of this invention resides in the provision of disconnect switch having a pair of transversely spaced and parallel switch blades hinged at one end to an insulator supported hinge arm, contact means disposed between said blades adjacent the opposite ends thereof for engaging the blades when the switch is closed, a wedge-shaped curved arm pivoted between the free ends of the blades and a pair of upstanding complimentary wedge-shaped arms having surfaces cooperable with the curved arm to provide pry out means for opening the switch.

Another object of this invention is to provide a disconnect switch having a pair of transversely spaced and parallel switch blades hinged at one end and cooperating contact means disposed between said blades to engage the blades when the switch is closed with a wedge-shaped curved arm pivoted between the free ends of the blades and providing an extension to be engaged by a hook stick and a pair of upstanding complementary wedge-shaped arms having surfaces cooperable with the curved arm to provide pry out means for opening the switch whereby a pry-out leverage advantage is obtained during the opening of the switch.

Further objects will appear as the description is read in connection with the appended claims and attached drawings wherein:

Figure l is a side elevational view of one embodiment of the present invention;

Figure 2 is an enlarged fragmental side elevational view of the free end contact and pry-out structure of the embodiment of the invention of Figure 1;

Figure 3 is an elevational view taken looking at Figure 2 from the right;

Figure 4 is an enlarged sectional view taken along line 4-4 of Figure 1 looking in the direction of the arrows with certain parts broken away and sectioned to better illustrate the blade guide and pry-out clamp bracket;

Figure 5 is a top plan view of the hinge end contact clamp bracket of Figure 1;

Figure 6 is a front elevational view of the hinge end contact clamp bracket of Figure 5;

Figure 7 is a top plan view of the combined latch supporting, pry-out lug clamp bracket of Figure 1 provided for securing the free end contact element in place on its supporting insulator;

Figure 8 is a side elevational view similar to Figure 1 illustrating a modified form of the invention provided for handling substantially higher currents;

Figure 9 is a view on an enlarged scale taken on line 99 of Figure 8;

Figure 10 is an enlarged fragmental side elevational view, similar to Figure 2, of the embodiment of the invention shown in Figure 9; and

Figure 11 is a view similar to Figure 3 of the embodiment of the invention shown in Figure 9.

With continued reference to the drawings wherein like reference numerals are used throughout to indicate the same parts and with particular reference first to the embodiment of the invention shown in Figures 1 through 7, numeral 20 indicates generally a hook stick switch of the present invention designed to handle currents of the order of 400 to 600 amperes at a 7.5 through 69 kv. ratmg.

Switch 20 is mounted conventionally on insulator stacks 18 and 19 spaced apart on a supporting frame 17 in well known manner and comprises in general a pair of parallel and transversely spaced blades 21 and terminal contacts 22 and 23 more fully hereinafter described. Blades 21 are hinged on upstanding arms 24 of a clamp bracket 25. A hinge bolt 26 mounted in arms 24 pivotally supports one end of blades 21 and is provided with spring cup washers 27 bearing against the outer faces of the blades 21 and held between the head of the hinge bolt and a nut and lock nut assembly threaded on the end of bolt 26. This hinge bolt and washer assembly constitutes a compression assembly which biases the blade ends toward each other to provide the desired high contact pressure in a manner that will be clear to those skilled in the switch art. As clearly seen in Figures and 6 bracket 25 comprises a base portion 28, generally circular in configuration, having depending side flanges 29 terminating at 30 and at 31 (Figure 5) to provide oppositely aligned passages for receiving the base leg 32 of generally L-shaped contact member 22 therebetween as shown in Figure 1. Base 28 of clamp bracket 25 is provided with a bolt opening 34 lying on the center line between the terminal ends 30 and 31 of depending flanges 29 and a pair of bolt holes 35 transversely spaced in base 28 so as to lie outwardly beyond the terminal ends 30 and 31 of depending flanges 29. Upstanding arms 24 of bracket 25, as clearly seen in Figures 5 and 6, are joined throughout their lower portions by a transversely extending web 36 off-set outwardly from flattened end 37 of base 28 to provide a contact backing web for a purpose to be hereinafter pointed out.

Web 36 as clearly seen in Figure 6 is provided with threaded aperture 38 adapted in use to receive a contact securing bolt 39 (Figure 1) provided to clampingly secure upstanding contact element 41 of contact 22 against backing web 36 to rigidly secure the contact element 22 and clamp bracket 25 together. As clearly seen in Figure 1, leg 32 of contact element 22 extends longitudinally between the terminal ends 30 and 31 of clamp bracket 25 and is suitably apertured in alignment with clamp bracket bolt opening 34 to freely receive the shaft of a securing bolt 43 threaded into the cap member 44 of conventional insulator stack 19. Cap 44 is also provided with a pair of transversely, outwardly disposed tapped bolt holes (not shown) in alignment with bolt holes 35 of clamp bracket 22 to receive the shank of an attachment bolts 47 adapted to secure clamp bracket 22 against relative movement with respect to cap 44 and retain ends 30 and 31 of depending flange 29 hearing against the side faces of contact leg 32 to position contact element 22 properly upon insulator cap 44. As clearly appears from Figmre l, the height of depending flange 29 is less than the thickness of leg 32 of contact element 22 so that upon tightening of bolts 43 and 47 the contact leg 32 will be rigidly clamped between cap 44 and clamp bracket 25.

In actual manufacture the spacing between switch blades 21 will be of the order of two inches and the side edges of the transversely extending contact 22 will be similarly dimensioned so as to overhang the side faces of upstanding arms 24 of bracket 25, which are respectively spaced apart one and seven-eighths inches to assure lateral protrusion of the upstanding contact element 41 beyond arms 24 in position to be closely and tightly engaged by the switch blades 21 in use. As will be apparent from Figures 1 and 5, the upstanding arms 24 are longitudinally off-set with respect to the exposed face of backing web 36 so that the contact element 41 of contact 22 will lie inwardly of hinge pin 26 toward the adjacent contact supporting insulator stack 18. The side faces of arms 24 adjacent their juncture with base 28 of clamp plate 25 are provided with laterally protruding lugs 52, the top surfaces of which are flattened to provide open switch position blade stops as will now be pointed out.

Referring to Figure 1, it will be noted that the rear ends of the blades 21 are cut away across one corner as indicated at 53. As a consequence, blades 21, when totated in a clockwise direction around hinge pin 26, will clear stops 52 until they reach a position approximately 90 removed from their closed position at which time the ends 54 of blades 21 will contact the upper ends of stops 52 to limit the counterclockwise movement of the blade at the full open switch position.

As will be clearly apparent from the dot-dash line showing of the blades 21 in Figure 1, the width of the blades is such that full contact is maintained between blades 21 and contact element 22 in all relative positions of the blades between closed switch and open switch position. This being true and as the contact portion 41 of contact 22 at all times engages the blades forwardly of the hinge pin and as the line terminal is directly connected to leg 32 of contact 22 through suitable bolt holes 55 shown in Figure 1, it will be appreciated that the direct electrical path in all positions of the switch blades will be from the blades to the contact element 41 of contact element 22, through contact 22 to the connected line terminal and that the hinge pin 26, spring washers 27 and clamp bracket 25 at no time provide the current path between the switch blades and the line terminal at the hinge end of the blade. As a consequence, arcing due to pivotal clearances and end clearances between the blades and the support arms 24 is at all times prevented and the heating up of the spring cup washers 27 that would likely occur if the hinge pin carried the load current is avoided. The spring washers, therefore, can be expected to retain their spring resiliency indefinitely to assure adequate contact pressure between the blades 21 and contact element 41 over long periods of time without servicing.

It will also be appreciated that the solid backing of contact element 41 provided by web 36 imparts substan tial rigidity to the upstanding contact element 41 relieving the upstanding element of any stresses that result from opening and closing of the switch under the high contact pressure maintained by the hinge pin and washer assembly.

Insulator stack 18 at the forward end of the switch carries a cap 56 which, like cap 44, is provided with three angularly spaced, tapped bolt holes similar to those mentioned in connection with insulator cap 44 for receiving similar securing bolts 43 and 47 provided to secure leg 57 of contact and terminal connector 23 between the base 59 of a combined latch supporting, pry-out lug, clamp bracket 61 and cap 56 in a manner similar to that heretofor described in connection with contact element 22. As clearly seen from Figures 4 and 7, base 59 of clamp bracket 61 is generally circular in configuration and is provided with bolt holes 34 and 35 and a depending flange 29 terminating at 30, 31 as previously described in connection with clamp bracket 25. Clamp bracket 61 also is provided with a flattened side 37 corresponding to side 37 of bracket 25 but differs in other respects as will be now pointed out.

Referring for the moment to Figures 1, 4 and 7, clamp bracket 61 at its flattened side is provided with a centrally located upstanding backing web or flange 62 flanked on either side by shorter upstanding lugs 63 of rectangular cross section providing blade engaging stops for limiting closing movement of the switch. The outer face of backing web 62 defines with respect to the plane of base 59 an angle of 85 and is provided with a tapped opening 64 adapted to threadedly receive a bolt 65 which passes through a suitable opening (not shown) in upturned contact element 66 to securely fasten contact element 23 rigidly to bracket 61. Uptanding web 62 has integrally formed therewith an upwardly and rearwardly extending right angularly disposed rib element 67 the purpose of which will be hereinafter pointed out.

Offset rearwardly beyond the transverse center line of clamp plate 61 are a pair of laterally spaced, upstanding, integrally formed cars 68 suitably apertured at 69 in transverse alignment to receive a pivot pin 70. Pin 70, as clearly seen in Figures 1 and 2, pivotally mounts a latch element 71 having a latch arm terminating in a latching finger 72 carrying a right angularly disposed cam pin 73. Latch element 71 is spring urged to latching position by a coil spring in well known manner and in angularly spaced relation around its hub is provided with a pair of opposite limit stop arms 74 and 75, the function of which will be apparent.

Leg 57 of contact element 23 like leg 32 of contact element 22 is provided with spaced apertures 55 adapted to provide a connection for a line terminal in well known manner.

Referring for the moment to Figure 4 of the drawing, it will be noted that the upper extremity of upturned contact element 66 tapers to a point to provide inclined, upwardly facing guide surfaces 76 for cooperation with switch blades 21 in a manner to be hereinafter pointed out. Contact element 41, as indicated at 77 in Figure 1, has short inwardly sloping walls terminating in a flat transversely extending top end wall 78. However, due to the constant contact engagement at the hinge end, the switch surfaces 77 normally have no guiding function.

As clearly seen in Figures 1, 2, 3 and 4 the ends of switch blades 21 remote from hinge pin 24 are connected together by a compression assembly made up of a headed bolt 81, the shank 82 of which extends through suitable openings provided adjacent the free ends of blades 21, a pair of cup spring washers 83 supported on shank 82 in engagement with the outer faces of switch blades 21 and a lock nut assembly 84. This compression assembly is effective to bias the free ends of switch blades 21 toward each other to create the desired high contact pressure in a manner well known in the art.

Shank 82 of bolt 81 also serves as a journal pin for mounting hook stick operating ring member 85 pivotally journaled on shank 82 by means of transversely spaced segernental end walls 86 integrally connected at their outer ends by arcuate wall portion 87. Wall 87 supports in transverse centered relation ring element 88 into which the hooked end of a hook stick. is inserted to operate the switch. Each end of ring shaped element 88 at its juncture with arcuate wall 87 is provided with a reinforcing web 89 provide to strengthen the ring element against stresses concentrated at the juncture with angular wall 87 in operation of the switch.

End walls 86 at their opposite corners of intersection with annular wall 87 are provided with transversely extending lugs 99 and 91 (Figures 1, 2 and 3) adapted respectively to engage the free ends of switch blades 21 in closed position and the longitudinal edges 92 of switch blades 21 in open switch position of the blades. Hook stick ring member 85 substantially midway between its end walls 86 is provided with a partition Wall (not shown) having an opening thercthrough to receive shank 82 of pin 81 and supporting thereon a pair of angularly related, outwardly extending arms 94 and 95 (Figure 2). Arm 95 is formed with a curved cam surface 96 adapted to overlie rib 67 for cooperation therewith to provide a pry-out mechanism for overcoming the high pressure contact forces incident to initial opening movement of the switch. This cam surface 96 in actual production is generated around a center disposed one and five-sixteenths inches to the right of the center of the journal opening provided for pin 82 and one inch below the center of the journal opening viewed in Figure 2.

Ring element 88 is formed around a center located two and five-sixteenth inches above the center of the journal opening and one and one-quarter inches to the right thereof using a one and one-half inch radius to form the inner curved portion lying adjacent wall 87, the straight portions providing the hook stick corner notch 97 at their intersection being right angularly related tangents to the resulting arcuate surfaces. These dimensions and center locations provide in actual practice a pry-out ring assembly having a three to one leverage advantage with the top of rib 67 as the fulcrum when a hook stick is engaged in corner notch 97 to operate the hook stick operating ring assembly in the conventional manner. It follows, therefore, that, when ring element 88 is engaged by a hook stick, arm 94 will first contact latch pin 73 forcing the latch to its unlatched position and then cam surface 96 of finger will engage the top of rib 67 providing a force multiplication, due to the leverage advantage, to pry the switch blades away from the bracket 61 in a clockwise direction. This leverage advantage accordingly is available to readily overcoming the initial resistance to movement due to the high contact pressures and during the first portion of the opening movement of the switch until the area of contact between contact element 66 and blades 21 is reduced sufficiently to permit the switch to be fully opened with a minimum of effort.

Blades 21 just beyond the face of contact element 66 nearest the hinge end of the switch is provided with a further compression assembly including a bolt 81, cup spring washers 83 and lock nut assembly 84 to assure the maintenance of proper contact pressure between blades 21 and contact 66. To further assure unitary movement and assembly of blades 21, the two blades are anchored together by a U-shaped copper bar 98 having its opposite end flanges 99 riveted to the respective blades by means of rivets 101. As clearly seen in Figure l, anchoring bar 98 is positioned approximately mid-way between the ends of the blades so that the opposite free ends of the blades may be flexed independently under influence of their respective compression assemblies. Also as clearly shown in Figure l, the free ends of the blades 21 are cut off at an angle as indicated at 102 to permit free passage of stop 90 in a clockwise direction during opening movement of the switch.

The contact edges of contact elements 41 and 66 are silvered as indicated by the letter S over the area covered by blades 21 in closed switch position to assure maximum contact efficiency. Due to the constant contact of blades 21 and contact 41 the silver coating on the hinge end contact is subjected only to rubbing contact with the wide faces of blades 21 and will not be materially injured by the usual opening and closing switch movements. The silver coating on contact element 66, however, would be subjected to highly injurious tearing forces, except for the backward sloping of contact element 66 which disposes the guide surfaces 76 in a position to engage the faces of blades 21 beyond the contact area of the faces. Accordingly, the blade edge in normal closing movement of the switch will make contact with guide surfaces 76 along an arcuate path G beyond the normal contact area of the blades and will be spread apart during closing movement of the switch by contact along this path with uncoated corners of contact 66. As a consequence wear and burring of the blades faces at points that might injure the silver coating or outwardly displace the blades is avoided in a simple and effective manner.

A modified embodiment of this invention is illustrated in Figures 8 through 11 of the drawings. The switch there shown has a 7.5 through 69 kv. rating but is adapted for use with currents ranging between 1200 to 2000 amperes. Except for differences hereinafter pointed out the elements of this switch are the same as the previously described embodiment and for this reason many of the parts are indicated by identical reference numerals without detailed description.

The most important difference between the switch of the present embodiment and that previously described is the provision of multiple contact elements and provision of blade guide means formed as extensions of backing web 62 of the clamp bracket 61. As clearly seen in Figure 8, the contact member at the hinge end of the switch is made up of contact element 22 providing contact portion 41 and a similar contact member 22a, leg 32a and contact portion 41a of which are slightly shorter than leg 32 and contact portion 41, disposed in nested superposed position with their upturned contact portions 41 and 41a spaced one from the other. The desired spacing between contact portions 41 and 41a is maintained by suitable spacer washers 111 disposed between the contact portions in surrounding relation to the four screws 65 provided to secure the contact portions to backing web 36.

To accommodate the double thickness resulting from superposed legs 32 and 32a, clamp plate 25 of this embodiment of the invention is provided with a substantially deeper depending flange 29a but is otherwise structurally the same as clamp plate 25 of the previous embodiment.

Turning to the contact structure on insulator 18, it will be noted that it also is made up of a pair of contact members 23 and 23a, the legs of the latter being substantially shorter to permit nesting of contact 23a in contact 23 with legs 57 and 57a in superposed relation to each other. Contact member 23, as in the previous form of the invention provides upturned contact portion 66 terminating in a pointed upper end providing inclined guide surfaces 76. Contact 23a on the other hand has an upturned portion 66a terminating at about the level of the top of the backing web 62.

As clearly seen in Figures and 11, backing web 62 is provided with two sets of laterally spaced attachment screws 65 having heads countersunk into the face of contact portion 66 and shanks extending through spacer washers 111 provided to space contact portions 66 and 66a apart and assure rigid clamping of the contact elements 66 and 66a to backing web 62. It should be noted that the contact elements 66 and 66a of this embodiment of the invention are disposed at a substantially 90 angle with respect to their leg portions 57 and 57a and therefore, do not slope as does the contact 66 of the previous embodiment.

As a result of this difference in construction and to assure that the silver contact coatings S will not be injured, backing web 62 of the present embodiment of the invention is made of double thickness along its edges and extended upward beyond edges 92 of blades 21a where it is widened out as indicated at 112 (Figure 9) to slightly overhang blades 21a. The outer faces of these upward extensions are inclined inwardly to provide guide surfaces 76a for guiding blades 21a into closed switch position. As clearly seen from Figure 9, the main body portion of web 62 is narrower than contact elements 66 and 660. As a consequence, blades 21a, so long as any portion remains in contact with the corners 112, will be spread apart sufficiently to clear the silvered contact edges of contact portions 66 and 66a.

This embodiment of the invention omits pry-out rib 67 and in its place provides the upper portion of web 62 with an upwardly opening V-shaped recess 113 the side faces of which are spaced apart sufiiciently to receive a wedge shaped cam finger 114 formed as an extension of wall 87 of hook stick operating ring assembly 85a. As will be apparent from Figure 10, finger 114 is longitudinally reinforced by a rib 115 and assembly 85a is provided between its end walls with finger 94 for cooperation with latch pin 73 in the manner previously described. Instead of two spaced stops 90 and 91, end walls 86 of operating ring assembly 85a are each provided with a compound stop in the form of a single, laterally protuding lug providing angularly related stop portions 90a and 91a.

In clogging movement of switch blades 210, stop 90a engages the free ends of blades 21:: to rigidly relate ring assembly a with the blades so counterclockwise movement can be effected with a conventional hook stick. In moving from closed to open position, ring assembly 85a first pivots on the bolt of compression assembly 81 releasing latch 71. During this initial movement, the tip of pry-out finger 114 moves freely through wedge shaped recess 113 until its side edges at the tip engage the side walls of recess 113 at the small end. Continued pivotal movement of ring assembly 85a produces a pryout force between the mating wedge surfaces of recess 113 and finger 114 initiating clockwise movement of blades 21 toward open position. Since pivotal movement of ring assembly 85a is permitted until stop portion 91:: engages edges 92 of blades 21a, it will be appreciated that approximately pivotal movement of ring assembly 85a is provided in this form of the invention. During this pivotal movement finger 114 executes a form of rolling motion in recess 113 progressively engaging successive areas of finger 114 and recess 113 to maintain approximately a three to one leverage advantage for a substantial period of time to overcome the frictional resistance between blades 21 and contacts 41, 41a, 66, and 66a and blade guide surfaces 112.

Referring to Figure 10, it will be noted that the silver stripping S is applied to the contact edges of contact portions 66 and 66a in staggered relation. This assures against either of the contacts hogging" the current in use of the switch.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. An electrical disconnect switch comprising a pair of insulator stacks rigidly supported in spaced relation to each other; a cap structure individual to each insulator stack; a terminal connector disposed in contact with the top surface of each cap structure and providing an upstanding transversely disposed coated contact portion; means associated with each insulator cap and terminal connector for fastening and immovably securing said terminal connectors to said insulator caps; a pair of switch blades hinged in transversely spaced relation to one of said insulator caps for swinging movement around an axis longitudinal offset outwardly beyond one of said upstanding contact portions and having a contact area adapted for constant engagement with the coated upstanding contact portion and remote laterally moveable contact ends swingable toward and away from the upstanding contact portion on the other insulator stack to make and break a connection with said last mentioned contact portion; guide means for spreading and guiding said remote contact ends into laterally spaced relation to said contact portion of said other insulator cap to efiect non-sliding engagement therewith, said guide means being offset longitudinally from said last mentioned contact portion to obviate wear and burring of said remote contact ends over the area engageable with said coated contact portion on the other insulator; and a hook stick operating ring pivotally mounted on said blades for moving said switch blades to open and closed switch positions.

2. The switch of claim 1 wherein said contact portion of the terminal connector associated with said other insulator stack is inclined away from the hinged end of said switch blades and has its uppermost end formed by oppositely inwardly inclined surfaces providing said guide means and said guide means is aapte to engage the inner faces of said laterally spaced switch blades to guide said blades into contacting engagement with the lateral edges of said contact portion and spread said blades apart by reason of engagement of the leading lateral contact edges of said contact portion along an arcuate path of said inner blade faces other than the contact portion of said inner faces.

3. The switch of claim 1 wherein said means for fastening said terminal connectors comprise respective clamp brackets and one of said clamp brackets is provided with upstanding, laterally spaced ears suporting a hinge pin for hingedly connecting said switch blades thereto.

4. The switch of claim 3 wherein said other clamp bracket is provided with upstanding, laterally spaced ears supporting a pivot pin which in turn carries a latch means comprising a lever journalled on said pivot pin and having a hook shaped end for positive engagement with a portion of said switch blades, a stop arm for limiting movement of said lever in one direction, spring means formoving said lever in said one direction and a stop arm for limiting movement of said lever in the other direction.

5. The switch of claim 4 wherein said guide means comprises an upstanding formation on said other clamp bracket the upper end of which is formed by oppositely, inwardly inclined surfaces the lower portions of which extend laterally slightly beyond the lateral edges of the said associated contact portion to provide guide surfaces located adjacent but spaced from one face of said contact portion to engage the inner faces of said blades along an arcuate path spaced from the area of said inner blade faces making electrical contact with the lateral edges of said associated contact portion.

6. A disconnect switch comprising a pair of insulator stacks rigidly supported in spaced relation to each other; a terminal connector supported by each of said stacks; an upstanding contact member supported by each of said stacks electrically connected to the respective terminal connectors and providing oppositely outwardly facing, laterally spaced contact surfaces; a pair of switch blades hinged in transversely spaced relation on one of said insulator stacks for swinging movement toward and away from the upstanding contact member on the other insulating stack to make and break a connection therewith; an upstanding pry-out member on said other insulator stack in adjacent relation to the contact member thereon having a centrally located upwardly diverging recess in its upper end; and a hook stick operating ring assembly pivotally mounted adjacent the free ends of said switch blades and having a finger portion of longitudinally curved Wedge shaped configuration disposed in overlying relation to the diverging recess in said upstanding pry-out member and adapted upon engagement of said hook stick operating ring with a hook stick and pivotal movement of said hook stick operated ring in switch opening direction to enter into said recess and engage the lateral walls thereof with a rolling movement thereby effecting a continuing pry-out action forcing said blades toward open switch position and out of contact with said upstanding contact member on said other insulating stack whereby the frictional pressure between said blades and the contact surfaces of said last mentioned contact member may be readily overcome with a minimum of effort until the area of contact is reduced to an inconsequential amount.

7. The disconnect switch of claim 6 wherein said contact and terminal connector comprise a unitary bar having a short contact leg and a long terminal connector leg and said short contact leg and said long terminal connector leg define between them a dihedral angle of the order of 85.

8. An electrical disconnect switch hinge end mounting comprising an insulator stack; a cap on said insulator; a contact in the form of a flat copper bar seated on said (ill cap and having an upturned contact end; a clamp bracket removably secured against relative movement with respect to said cap and having a recess therein for receiving said copper bar and clampingly engaging said copper bar to said cap; a pair of transversely spaced switch blades hinged to said bracket in position to straddle said upturned contact end of said copper bar and engage the transversely spaced edge portions of said upturned contact end.

9. A disconnect switch contact and terminal eonncctor structure for use in an insulator stack supported disconnect switch comprising an L-shaped contact and terminal connector bar of substantial width having a short leg containing a bolt opening and providing contact surfaces along its upstanding edges and a long leg rovided with through openings adjacent its free end adapting said leg for connection to a line terminal connector and a bolt opening adjacent said short leg; a clamp bracket comprising a planar base having depending segmental flange portions along opposite sides thereof for receiving a portion of said long terminal connector leg therebetween. a plurality of bolt openings therein one of which is located for alignment with the bolt opening of said long leg of said L-shaped bar and the others of which are located in straddling relation to said long leg. and an upstanding planar portion narrower than said contact leg formed on the upper surface of said base and extending laterally with respect to said segmental fiange portions and located at an end of said base portion, said planar portion having a tapped opening in position to line up with the bolt opening in said short contact leg when said contact leg is brought into contact with its outwardly disposed face; fastening means having a threaded shank passing through the opening in said short contact leg and threaded into said tapped opening in said planar portion to secure said contact leg rigidly thereto with its contact edges projecting laterally from said planar portion; and fastening means for each of said bolt holes in said base portion each of said fastening means having a threaded shank passing through its respective bolt opening for threaded engagement with tapped openings in the top surface of said insulator stack to securely fasten said clamp bracket to said insulator stack with said long terminal connector leg clamped between said clamp bracket base and the top surface of said insulator stack.

10. The contact and terminal connector structure of claim 9 wherein said short contact leg and said long terminal connector leg define between them a dihedral angle slightly less than and said outwardly disposed face of said upstanding planar portion is similarly inclined to abuttingly engage the inner face of said short contact leg.

11. An electrical disconnect switch comprising a pair of transversely spaced switch blades; means spring biasing said blades toward each other to assure a high contact pressure; a first insulator stack; means on said first insulator stack defining a hinge for said pair of blades; a second insulator stack; a flat copper bar seated on said second insulator and having an upturned end disposed to be received between said blades and provide transversely spaced oppositely facing contact edges for engagement with said blades; guide means on said second insulator defining an upwardly diverging recess between a pair of transversely spaced, oppositely facing camming surfaces; a hook stick operating ring disposed between and pivoted on said blades; and a longitudinally curved lever of wedge shaped cross-section on said ring having an end adapted to move into said recess and side faces to engage said camming surfaces to apply a substantially constant leverage pry-out force during switch opening pivotal movement of said ring to overcome the high contact pressure of said blades on said contact edges.

12. A switch comprising a pair of transversely spaced blades: a first insulator; means on said first insulator defining a hinge for said pair of blades; a second insulator; a flat copper bar seated on said second insulator and having an upturned end disposed between said blades and having transversely spaced edges thereon engaging said blades; a plate on said second insulator in clamping engagement with said copper bar; an operating ring disposed between said blades and pivoted on said blades; an upstanding fulcrum member on said plate; and a curved finger on said ring having a free end adapted to seat on said upstanding fulcrum member and form a prying means for said switch.

13. The switch of claim 12 wherein said curved finger lies between said blades and provides a longitudinally extending arcuate cam abutment surface generated around a center disposed toward the hinge end of said switch and outwardly from said fulcrum member in the direction of opening movement of said switch a distance just sufficient to assure an effective leverage ratio of the order of 3 to 1 between the operating ring pivot center and the hook stick notch of the operating ring and the operating ring center and the fulcrum point and said upstanding fulcrum member provides a planar end face extending lengthwise from said upturned end of said bar toward said operating ring in the longitudinal plane of said curved finger in position to be rollingly engaged by said arcuate cam abutment surface as the operating ring pivots during opening movement of said blades thereby effectively progressively shifting the point of abutting contact between said finger and said planar end face toward said upturned bar end as the pivot axis moves away from the planar end face whereby the effective pryout force is maintained substantially constant.

14. A high current disconnect switch having a pair of transversely spaced and parallel switch blades mounted for pivotal movement into and out of engagement with a switch contact; and a high current switch contact comprising a first upstanding member disposed between said blades when the switch is closed and having transversely disposed contact edges thereon engaging said blades, :1 second upstanding member disposed between said blades when the switch is closed and having transversely disposed contact edges thereon engaging said blades, a pair of transversely spaced upstanding arms, means securing said first and said second upstanding members to said upstanding arms, and a curved arm pivoted on said blades and turnable to engage said upstanding arms to define therewith pry-out means in the opening of said switch.

References Cited in the file of this patent UNITED STATES PATENTS 1,819,779 Hoye Aug. 18, 1931 1,966,894 Jacobs July 17, 1934 1,971,392 Carlisle Aug. 28, 1934 2,063,954 Ramsey Dec. 15, 1936 2,202,170 Smythe May 28, 1940 2,498,250 Cole Feb. 21, 1950 2,531,165 Scheuermeyer Nov. 21, 1950 2,566,917 Armstrong Sept. 4, 1951 2,630,510 Hoifman et al. Mar. 3, 1953

Images