US2753407A - Switch contacts - Google Patents

Description

July 3, 1956 w. HOLLANDER SWITCH CONTACTS 4 Sheets-Sheet 1 Filed Aug. 20, 1953 h NQ N mWN NQN msvw Iii g INVENTOR.

July 3, 1956 w. 1.. HOLLANDER SWITCH CONTACTS 4 Sheets-Sheet 3 Filed Aug. 20, 1955 July 3, 1956 w. L. HOLLANDER SWITCH CONTACTS 4 Sheets-Sheet 4 Filed Aug. 20. 1955 INVENTU'R. wmfam SWHCH CNTACT William L. Hollander, Centralia, Ma, assignor to A, 15. Chance Company, Centralia, Mo, a corporation of Misseuri Application August 20, 1953, Serial No. 375,488 6 Claims. (Cl. Mitt-48) The present invention relates to switch contacts, and is particularly concernd with the improved contact structure for a high voltage air-break switch assembly.

This application is a continuation in part of my prior application, Serial No. 286,794, filed May 8, 1952, for High Voltage Air-Break Switch Assemblies.

One of the objects of the invention is the provision of an improved fixed contact structure for use with a pivoted and rotating switch arm, which contact structure is adapted to permit the switch blade to be moved to the closed position and then rotated to bring the blade contact and fixed contacts into a better engaging position.

Another object of the invention is the pro-vision of fixed contacts for a switch assembly of the class described, which are adapted to engage the blade in such manner that one of the contacts serves as a fulcrum point, direct ing all of the final closing effort into rotation of the blade around this fulcrum into high pressure engagement between the blade and fixed contacts.

Another object of the invention is the provision of improved fixed contacts for a switch of the class described, in which the fixed contacts are provided with locking projections which resist the electromagnetic forces which tend to force the blade open during heavy fault current.

Another object of the invention is the provision of an improved fixed contact structure for switches of the class described, which are so constructed that extra high speed slamming of the switch arm will not cause the blade to go past its proper position.

Another object of the invention is the provision of a switch contact structure which is provided with a fulcrum projection which causes the blade to come to the final locked position with less effort because all of the final operating effort is devoted to twisting the blade.

Another object of the invention is the provision of improved contact structures which are adapted to facilitate the making or the breaking of the circuit in spit of ice, corrosion or other obstructions.

Another object of the invention is the provision of improved contact structures which are simple, sturdy, capable of economical manufacture, protected against mechanical damage, weather and ice, and adapted to function more cfiiciently and more dependable than devices of the prior art.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are four sheets, accompanying the specification:

. l is a fragmentary, side elevational view of a voltage airbreak switch assembly embodying the present invention;

Fig. 2 is a fragmentary end elevational view taken from the right of Fig. 1, showing the switch in the closed position;

' Fig. 3 is a view similar to Fig. 2, showing the switch States Patent in an intermediate position just before the final twisting action;

Fig. 4 is a fragmentary top plan view of the arrangements for mounting the switch blade for pivotal move- 5 ment and for rotation;

Fig. 5 is fragmentary, sectional view taken on the plane of the line litof Fig. 4;

Fig. 6 is a fragmentary, sectional view taken on the plane of the line lll-li of Fig. 5;

Fig. 7 is a view similar to Fig. 6, showing a further improvd and preferred modification;

Fig. 8 is a diagrammatic illustration showing the various axes of the switch assembly for explanation of its operation;

Fig. 9 is a fragmentary ene elevational View how ing a modified form of fixed contact structure;

Fig. 10 is an enlarged end view of the switch blade structure of Figs. 2 and 3;

Fig. 11 is a fragmentary, side elevational view showing a modifid form of structure for the end of the blade;

Fig. 12 is an end elevational view taken from the right side of Fig. 11;

Fig. 13 is a view similar to Fig. 9, showing the preferred form of fixed contact structure;

Fig. 14 is a fragmentary, side elevational view of the contact structure of Fig. 13, shown in connection with the switch blade.

Referring to Fig. 1, this shows one example of a high voltage air break switch embodying the contacts which are the subject of the present application, and for which they are peculiarly adapted.

The switch includes two fixed insulators 42. and i l fixedly mounted upon a steel supporting channel (not shown), which also rotatably supports the central in sulator 42. The fixed insulator 42 fixedly supports a bridge '76 of electrical conducting metal, which terminates in a connector 75 to which the circuit is connected.

At its other end the bridge 7s is provided with an arm 2% having a bearing for receiving the trunnion 246 carried by the upper end of rotating insulator 43. Thus the rotating insulator is also rotatably mounted on the bridge 76. The bridge '76 terminates at its right end in a pair of spaced supporting flanges 24%, each of which is provided with a threaded trunnion Qt) threaded into the flanges ass and extending toward each other.

Threaded trunnions 9% have cylindrical portions 93, which pivotally support the blade housing 94 for movement into and out of closing position on a horizontal axis, as shown in Fi g. l in dotted lines.

The blade housing 94 (Fig. 5) is provided with a pair of bearings ill, M2 for rotatively supporting a cylindrical switch blade 24, which rotates upon its own axis. The trunnions 9b are provided with conical ends 96 which engage in complementary apertures in the end flanges 159, idtl of a shunt 97. The shunt 97 has a cylindrical portion 152, which partially embraces the switch blade 24-!) with which it has rotating sliding contact.

The shunt 97. is bent outwardly at 154, 155 and has horizontal portions 157 supporting the end flanges 159. The shunt 97 resiliently clamps the switch blade 240 and springs outward into engagement with the trunuions 90; and the shunt maintains a good electrical connection between the blade Zttlt and the bridge 76, by-passing the pivotal arrangements.

The blade 240 supports a crank 242 (Fig. 5) by means of which it is rotated; and the crank has a depending diagonal tubular portion 243. The rotating insulator 43 carries a plate 245, which has a diagonal extension 250 provided with a stub shaft 253, which extends into the tubular portion 243 of the crank.

Stub shaft 253 carries a carbon ball 255, haying a limited universal motion in the bore of tube 243.

The blade 240 is provided with a flattened end portion 140, which is substantially, elliptical, as shown in Fig. 10, having its widest dimension between the ends 145 of the ellipse and its narrowest dimension between the sides 144 of the ellipse. This permits the blade end Mil to enter between the fixed contacts 146 with the narrowest dimension and then to be twisted, as shown in Figs. 2 and 3, to arrive at the position of Fig. 2, where its longest dimension extends transversely to the contact, which the blade engages more tightly for better contact.

The elliptical end 14b is provided with a solid filler block 141, having a threaded bore 14-2. for receiving the arcing wire 6'7, which cooperates with a horn I164.

Referring to Fig. 11, this shows another form of blade end, in which the blade 68a is provided with a casting 1% having a cylindrical shank 185 mounted in the blade and secured by deforming the blade at 189 into the grooves 188.

The blade end 190 is rectangular in side elevation and has parallel sides extending from one end 91 to the other end 191. The ends of the blade are rounded at 191; and the blade has a central hub 1% with a threaded bore 193 for receiving the arcing wire. Here again the blade end is narrow in one dimension and is relatively wide in the other dimension.

The fixed contacts of the simplest type with which the blade cooperates are mounted upon the fixed insulator 44- by means of plate 46 and bolts 1 .43 threaded into the plate. Fixed contact 146 comprises a U-shaped member provided with two parallel sides, which may have a partially cylindrical curvature at 147 near the yoke.

Both blades flare outward at their upper end portions 59 and 50a; and the left leg is preferably formed with a pair of inwardly extending humps or ribs 6d and 58.

The action of the switch blade in connection with these contacts is as follows: In Fig. 1 and Fig. 2 the blade end 140 has tight engagement with the contacts 146 because it extends with its widest dimension between the contact legs. When the insulator 43 is rotated in a counterclockwise direction, looking downward, stub shaft 253 first actuates the crank 243 to rotate the blade in a counterclockwise direction on its own axis.

The blade then moves from the position of Fig. 2 to that of Fig. 3, being rotated on its own axis to relieve the pressure between the blade end and the contacts.

This also breaks loose any ice formations. rotation of the rotatable insulator 43 moves the crank 243 to the dotted line position of Fig. 1, during which the switch blade is given some slight additional rotation, but is pivotally moved out of engagement with the contact 14-6 to the dotted line position of blade 2% in Fig. 1.

Upon the closing of the switch a reverse action takes effect, as follows: The crank 243 moves in a clockwise direction, looking down from the top, from the dotted line position of Fig. 1 toward the full line position. This causes a slight rotation of blade 240 on its own axis, but mainly causes a pivotal movement of the blade 240 downward from the dotted line position of Fig. 1 to the full line position.

The blade end 140 enters between the contact legs 14.6 in a diagonal position, as shown in Fig. 3; and one of the ends 145 of the blade end engages the hump 58, which acts to limit the pivotal movement downward of the blade. Thereafter further rotation of the rotatable insulator 43 twists the blade on its own axis from the the position of Fig. 3 to that of Fig. 2, spreading the contact legs and engaging them more tightly to establish a better contact.

The hump 60 is engaged by the end portion 145 of the blade to aid in limiting this motion and acts as a stop.

Referring to Figs. 9, 11, and 12, these are modifications of the blade end and contacts, which are preferably employed in larger switches.

In this case the contacts 45 are mounted upon a metal base plate 42 carried by the fixed insulator 44 by means Further i d of a bolt 47 passing through a shoe 46. Shoe 46 has a plurality of threaded bores for receiving screw bolts 49, which support a plurality of springs 51, 52 and the actual contacts, indicated at St), the springs being on the outside and urging the contacts 5%) toward each other.

As the springs carry no current, the current being carried by the more conductive contacts 50, the springs do not become heated and do not lose their resiliency. in this case the two contacts 5% again have diverging upper ends 57; but the contacts are made of two separate pieces carri d by the shoe 46.

The left contact member 50 has the same stop humps 5d and 6t) and is preferably provided with a third stop rib 59 at its upper end, where the contacts begin to diverge.

The stop rib 59 serves as a safety stop for preventing the blade from being forced open due to electromagnetic force caused by heavy fault current.

Referring to Fig. 7, this shows a construction similar to Fig. 6, except that the shunt is provided with U-shaped resilient springs 161, which carry no current and maintain the resiliency of the shunt and good contact at all times.

Referring to Fig. 8, this is a diagrammatic illustration showing the various axes about which the parts of the switch rotate. 272 is the vertical axis of the rotating insulator, 273 is the axis of the blade 68; and 274 is the horizontal axis on which the blade housing pivots.

By giving special attention to the end Mil of the blade in the full line position and the dotted line position, it will be seen that when the switch is closed, in the full line position, the longest dimension of the blade end extends transversely to the contacts.

As the crank is rotated the blade 68 is rotated out of this position, relieving the contact pressure, after which the blade is lifted to the dotted line position; but rotation of the blade continues until, the dotted line posiion, the longest dimension of the blade end is at right angles to the full line position.

Referring to Figs. 13 and 14, these show a preferred modification of the contact structure. The contacts are again carried by a shoe 46, and include the left and right contacts 51? and 50a with diverging ends 57. A pair of springs 51 and 52 is located outside of each contact 50 to maintain the resilient characteristics of the contact.

The contacts are secured to the shoe by the screw bolts 49 and by additional screw bolts 49a. The left contact 54) again has the rib or hump 58 and a plurality of additional ribs 64 fitla, and dtlb just below the diverging portion 57. The other contact 50a has a transverse rib 600.

The stop ribs 58 and 600 serve as stops for causing the blade to come to rest in its pivotal movement in a position when pivotal movement ceases; and the remainder of the motion of the blade is mainly by twisting.

The stop 6th: then serves as a fulcrum point against which all the final closing efiort is urged to cause the blade to rotate around this point into high pressure to the dotted line position shown in Fig. 13.

The ribs 60, otla, and Gtlb serve as stops to limit the rotating of the blade, which comes to rest against the stop 6%; but the extra stops 60a and 60b are safety stops for preventing opening of the switch blade by the heavy magnetic forces which are caused by fault current.

By having the two stops 58 and 60c, one on each contact, the two edges of the blade make contact with both these stops simultaneously. Extra high speed slamming of the blades will not cause the blades to go past the stops by whipping.

In the present switch construction the operating mechanism goes past dead center of the crank 274 to the final closed position; and the blade necessarily dips down and starts to rise as it comes to rest.

The provision of the extra stop 600 causes the blade to come to the final locked position with less effort than that required to slide the blade upward against increasing high pressure because all of the final operating efiort is converted to torque on the blade.

Referring to Fig. 14, this side elevation of the contacts shows that they are arranged in pairs on each side, thus giving a greater contact area and less contact resistance between the contacts and the end of the blade.

It will thus be observed that the contacts in the present switch have been particularly constructed and shaped to facilitate the more satisfactory operation of a switch blade of the lifting and twisting type.

The present contacts are backed up with springs, which maintain the resiliency of the assembly because the springs do not need to carry any current. The switch blade comes to rest between the contacts, engaging a stop on each of them simultaneously; and these stops facilitate the further engagement of the blade in tight contact position because the blade rotates, utilizing one of the stops as a fulcrum until the blade extends transversely to both contacts at substantially right angles.

While I have illustrateda preferred embodiment of my invention, many modifications may be made without departing from the spirit of theinvention, and I do not wish to belimited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of theappended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a switch of the type having a fixed insulator provided with pivots on a horizontal axis, a blade housing mounted on said'pivots for moving a blade in an arcuate direction, a blade rotatably mounted in said blade housing on its own axis, and having an end contact which is wider in a direction transverse to said arcuate direction, and means for moving the blade through an arc to close the switch and for rotating the blade to effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by aid supporting member, and forming an upwardly open U-shaped fixed contact assembly, said contacts diverging at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the wide blade contact is tilted downwardly toward said one contact, and said one contact having an inwardly projecting ridge engaging said downwardly tilted lead ing edge and resisting further arcuate movement of the blade, while aiding in the rotation of the blade on its own axis, to move said wide blade contact into horizontal contact spreading engagement, the other contact of said U-shaped assembly being provided with an inwardly projecting ridge located below the wide blade contact when it is in horizontal spreading engagement for preventing over-travel of said blade member.

2. In a switch of the type having a fixed insulator provided with pivots on a horizontal axis, a blade housing mounted on said pivots for moving a blade in an arcuate direction, a blade rotatably mounted in said blade housing on its own axis, and having an end contact which is wider in a direction transverse to said arcuate direction, and means for moving the blade through an arc to close the switch and for rotating the blade to effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by said supporting member, and forming an upwardly open U-shaped fixed contact assembly, said contacts diverging at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the wide blade contact is tilted downwardly toward said one contact, and said one contact having an inwardly projecting ridge engaging said downwardly tilted lead edge and resisting further arcuate movement of the contact spreading engagement, the othercontact of said U-shaped assembly being provided with an inwardly projecting ridge located below the wide blade contact when it is in horizontal spreading engagement for preventing over-travel of said blade member, and the other contact also having a plurality of regularly spaced inwardly projecting ridges located above said wide blade contact, when the latter is in horizontal position, to prevent opening of the switch byheav'y fault currents.

3. In a switch of the type having a fixed insul'a'tor provided with pivots on a horizontal axis, a blade housing mounted on said pivots for moving a blade in an arcuate direction, a blade rotatably mounted insaid bladehousing on its own axis, and having an end contact which iswider in a direction transverse to said arcuate direction, and

means for moving the blade through an arc to "close the switch and for rotatingthe blade to' effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by said supporting member, and forming an upwardly open U-shaped fixed contact assembly, said contacts diverging at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the wide blade contact is tilted downwardly toward said one contact, and said one contact having an inwardly projecting ridge engaging said downwardly tilted leading edge and resisting further arcuate move ment of the blade, while aiding in the rotation of the blade on its own axis, to move said wide blade contact into hori- "zontal contact spreading engagement, the other contact of said U shaped assembly being provided with an inwardly projecting ridge located below the Wide blade contact when it is in horizontalspreading engagement for preventing over-travel of said blade member, and the other contact also having a plurality of regularly spaced inwardly projecting ridges located above said wide blade contact, when the latter is in horizontal position, to prevent opening of the switch by heavy fault currents, each contact comprising an engaging member of high electrical conductive metal backed up on the outside by a pair of engaging and backing springs, forming a laminated assembly bolted together.

4. In a switch of the type having a fixed insulator provided with pivots on a horizontal axis, a blade housing mounted on said pivots for moving a blade in an arcuate direction, a blade rotatably mounted in said blade housing on its own axis, and having an end contact which is wider in a direction transverse to said arcuate direction, and means for moving the blade through an arc to close the switch and for rotating the blade to effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by said supporting member, and forming an upwardly open U- shaped fixed contact assembly, said contacts diverging at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the Wide blade contact is tilted downwardly toward said one contact, and said one contact having an inwardly projecting ridge engaging said downwardly tilted leading edge and resisting further arcuate movement of the blade, while aiding in the rotation of the blade on its own axis, to move said wide blade contact into horizontal contact spreading engagement, the other contact of said U-shaped assembly being provided with an inwardly projecting ridge located below the wide blade contact when it is in horizontal spreading engagement for preventing over-travel of said blade member, said U-shaped contact assembly comprising, a channeled base having a pair of upwardly projecting flanges, a pair of contacts secured to the outside of said flanges, opposing each other, and a pair of springs engaging each of saidcontacts being secured in each case by a pair of screw bolts extending through them into said channeled base.

5. In a switch of the type having a fixed insulator provided with pivots on a horizontal axis, a blade housing mounted on said pivots for moving a blade in an arcuate direction, a blade rotatably mounted in said blade housing on its own axis, and having an end contact which is wider in a direction transverse to said arcuate direction, and means for moving the blade through an arc to close the switch and for rotating the blade to effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by said supporting member, and forming an upwardly open U-shaped fixed contact assembly, said contacts diverg ng at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the wide blade contact is tilted downwardly toward said one contact, and said one con tact having an inwardly projecting ridge engaging said downwardly tilted leading edge and resisting further arcuate movement of the blade, while aiding in the rotation of the blade on its own axis, to move said wide blade contact into horizontal contact spreading engagement, the other contact of said U-shaped assembly being provided with an inwardly projecting ridge located below the wide blade contact when it is in horizontal spreading engagement for preventing over-travel of said blade member,

said blade comprising, a cylindrical tube, the said tube being deformed into elliptical shape at its contact end and having a solid elliptical block inserted in said elliptical end and secured therein.

6. In a switch of the type having a fixed insulator provided With pivots on a horizontal axis, a blade housing mounted on said pivots for moving a blade in an arcuate direction, a blade rotatably mounted in said blade housing on its own axis, and having an end contact which is wider in a direction transverse to said arcuate direction, and means for moving the blade through an arc to close the switch and for rotating the blade to effect a tight contact, a switch contact assembly comprising a fixed insulator, a metal contact supporting member on said fixed insulator, a pair of upwardly extending contacts carried by said supporting member, and forming an upwardly open U-shaped fixed contact assembly, said contacts diverging at the open end of said U-shaped assembly, one of said contacts being located to engage the leading edge of said wide end contact on said blade, while the wide blade contact is tilted downwardly toward said one contact, and said one contact having an inwardly projecting ridge engaging said downwardly tilted leading edge and resisting further arcuate movement of the blade, while aiding in the rotation of the blade on its own axis, to move said wide blade contact into horizontal contact spreading engagement, the other contact of said U-shaped assembly being provided with an inwardly projecting ridge located below the wide blade contact when it is in horizontal spreading engagement for preventing over-travel of said blade member, the said blade comprising a tubular metal member and having a cast metal contact provided with a cylindrical shank inserted in the end of said tubular member, and having depressions in said shank, said shank carrying an integral contact member relatively thin in one direction and relatively long, and provided with rounded ends in the other direction, said tube being deformed into said depressions to secure the contact on the tube.

References Cited in the file of this patent UNITED STATES PATENTS 2,359,056 Shaw Sept. 26, 1944 2,359,105 Graybill Sept. 26, 1944 2,363,360 Rawlins Nov. 21, 1944

Images