US3148252A

US3148252A - Conductive hinge structure for electric switch

Info

Publication number: US3148252A
Application number: US88543A
Authority: US
Inventors: Bernatt Joseph
Original assignee: Kearney James R Corp
Current assignee: James R Kearney Corp
Priority date: 1961-02-10
Filing date: 1961-02-10
Publication date: 1964-09-08
Anticipated expiration: 1981-09-08

Description

3 Sheets-Sheet 2 m 0 m E INVENTOR. JOSEPH BERNATT BY ATTORNEYS J. BERNATT CONDUCTIVE HINGE STRUCTURE FOR ELECTRIC SWITCH Filed Feb. 10, 1961 3,148,252 CONDUCTIVE HINGE STRUCTURE FOR ELECTRIC SWITCH Filed Feb. 10, 1961 J. BERNATT Sept. 8, 1964 3 Sheets-Sheet 3 uvmvrm JOSEPH BERNATT' was ATIQRNEXS United States Patent 3,148,252 CGNDUC'HVE HINGE SRUGTURE FGR ELEUIRIQ SWITCH Joseph Bernatt, Elnrhurst, Ill., assignor to James R.

Kearney Corporation, t. Louis, Mo., a corporation of Deiaware Filed Feb. 10, 19-61, Ser. No. 88,543 8 (Iiairns. (Cl. 2ttii48) The present invention relates to high pressure contact switches for high voltage electric circuits and more particularly to disconnect switches adapted to establish a high pressure contact between the relatively movable parts thereof which conduct the electric current from a source to a load. When so constructed, all of the connections in the electric circuit through the disconnect switch will be through elements in high pressure contact with one another, which will make it possible to omit all flexible electric connections, such as pigtails, auxiliary brushes and the like.

High pressure contact types of disconnect switches are generally Well-known and are shown, for example, in the patent to Froland, 2,420,074 of May 6, 1947. In this type of switch disconnect, there are usually three insulators parallel and mounted in a single plane, one carrying the stationary switch contact, the second carrying the movable contact arm assembly, and the third carrying the operating crank or assembly for the movable contact arm. The movable contact arm is arranged so it is rotated angularly from a position substantially 90 or more away from its contacting position to a position where it engages the stationary contact and, thus, effects the electric circuit. In this type of switch disconnect, the movable contact arm is also arranged so that after its contact carrying end enters the stationary contact the movable contact arm is rotated about its own axis. The end of the movable contact arm has a beaver tail sort of construction so that it enters the stationary contact readily, but when rotated in the manner mentioned, it produces a wedging effect in the fixed contact and a resulting high contact pressure. Because the load and voltage carried by the switch disconnect is high, it is required that the mechanical support permitting movement of the movable contact arm be constructed to carry the heavy electrical loads without heating, or separate pigtails be connected to provide sufficient electrical capacity in the electric conductive path to the movable contact arm.

In instances where the pigtail or other conductive connections to the movable contact arm were located and arranged to be protected from the elements, they have been acceptable. In cases where the arrangement was such that the protection was incomplete, it sometimes happens that the switch operation is not entirely satisfactory due to ice formation or some other unforeseen hazard. For example, in the Froland switch, the movable contact arm acts as a sort of bridge, when closed, to conduct the current from one set of fixed contacts adjacent the hinge for the movable blade to another set of fixed contacts at the tip of the blade. In this type of switch, it is obvious that neither set of fixed contacts could be adequately protected from the elements, and, while the construction has been widely accepted for commercial use, there have been certain minor objections to it because sometimes alignment difiiculties increased the operating elfort under normal conditions or due to icing.

According to this invention, an enclosed mechanical hinge structure for an electric disconnect switch is moditied to include suitable enclosed and protected electrical conductive parts to produce a low resistance conductive path or shunt for the electric current from an electric terminal to the hinged blade of the disconnect switch.

The present invention has for its primary object a me- 3,148,252 Patented Sept. 8,1964

chanical hinge structure for an electric disconnect switch which is enclosed and protected from the elements.

Another object of this invention is the construction or modification of a hinge for an electric disconnect switch to incorporate electrical connections protected from the elements and providing a low resistance conductive path for the electric current through the hinge, from an electric terminal to the hinged blade of the disconnect switch.

Another object of this invention is to provide a disconnect switch of the type having an angularly rotatable end on a swinging contact arm with current carrying contact connections between the contact arm and the support on which it rotates angularly as well as swings.

Another object of the present invention is to provide a disconnect switch of the type having an angularly rotatable as well as swinging contact arm with a single means to connect that arm with its support which will be protected, and form a low resistance conductive path for the electric current from an electric terminal to the hinged blade of the disconnect switch.

Another object is the construction and arrangement of the electric conductive hinge parts between the fixed terminal and the switch blade so as to provide for complete enclosure thereof.

Another object of the invention is to provide in a switch of this type a single pair of electric conducting elements which will accommodate swinging as well as rotation of the switch blade.

Further objects and advantages of this invention will appear from the following detailed description which is in such clear, concise and exact terms as to enable any one skilled in the art to make and use the invention when taken in conjunction with the disclosure in the accompanying drawings forming a part thereof and in which:

FIG. 1 is a side elevational view illustrating one form of switch to which this invention may be applied; FIFKi. 2 is a top plan view of the switch shown in FIG. 3 is an end view taken from the hinged end of the switch blade showing a sub-assembly of elements located adjacent the hinge for the blade; 7

FIG. 4 is a fragmentary top plan View of the portion of the switch adjacent the hinge showing the elements partly in section to illustrate the assembly; and

FIG. 5 is an exploded view in perspective of the several parts forming the hinge and contacts.

Turning now to FIG. 1 of the drawings, the disconnect switch elements include a base I of channel iron of suitable dimensions. Bolted to the channel iron 1 at spaced points are a pair of brackets 2 and 3 secured to the channel iron 1 by the bolts 4 and 5, respectively. Each of these brackets in turn supports an insulator member, such as 6 and 7, secured to the brackets 2 and 3, respectively, by

bolts

8 and 9. At the top end of the insulator 6 is a fitting 12 secured thereto by suitable bolts, not shown. This fitting includes an extension 14, the upper side of which is recessed at 16 and provided with spaced holes 18 and 20 for bolts which are used to secure a conductor between a clamping plate and the terminal 14. The fitting 12 also has bolted thereto a pair of spaced spring type of fixed contacts 24 and 26 secured by a pair of bolts, such as 23 and 32, respectively. Both contacts are preferably identical and their free ends are bent upon themselves in"the form of a U so as to provide a slot in which the end of the movable arm 36 is wedgingly engaged. The fitting 12 also carries a small extension 38 mounting a stop screw 40 which limits the movement of the end 36 of the movable arm of the switch in a switch closing direction.

The insulator 7 carries a bracket 11 secured to the top of the insulator 7 by suitable bolts, such as 13, one of which is shown in FIG. 1. This bracket 11 is better shown in FIG. 3, and, referring specifically to that figure, it will be seen that the bracket 11 has a circular base 15 which seats on top of the end of the insulator 7.

Divergent arms

17 and 19 carry spaced

hollow boss members

23 and 25, respectively. From this view, it will be apparent that bracket 11 forms an auxiliary support for the hinge contact arm 29 of the disconnect switch mechanism. Returning now to FIG. 1, the bracket 11 also carries a small extension 31 projecting vertically therefrom, which in turn is apertured to receive a stop screw 33 locked in position in the aperture by suitable stop nuts. Whereas the two insulators 6 and 7, heretofore described, are mounted on fixed mountings in fixed position with respect to the base 1, nevertheless, they are reversable in position if it is desired to mount the switch disconnect in an inverted position. This is likewise true of the insulator 45 which is supported on a flange 46 rotatable with the vertically mounted shaft 50. Bolts 48 attach the insulator to the flange. Shaft 50 is rotatably mounted in a bearing support 52 secured to the channel member 1 by

bolts

54 and 56, respectively. Bolt 56 also anchors in position a bracket 57 carrying an adjustable stop nut 59. The stop nut 59 is aligned with the end of a short arm 60 turning with the shaft 50 and limits the rotative motion of the shaft 50 in one direction. One end of the shaft 50 projects below the base 1 and may be provided with a fitting, such as 61, secured thereto against rotation, and upon which may be mounted a suitable arm for connection with a linkage to turn the shaft 50.

Supported at the top of the insulator 45 is a crank 04 suitably secured by a plurality of bolts, such as 66 and 67. The end of the crank 64 is pinned to a clevis s9 which is rotatable within a boss of the forked bracket '70. The branched arms of the bracket 70, indicated as 72 and '74, straddle spaced ears 76 and 79 of a control arm 77 rigidly secured to the contact arm 29 of the switch. A pin 75 forms the rotatable connector between the spaced arms 72 and 74 of the bracket 70 and the control arm 77.

The crank 64 has a bearing part, indicated generally as 80, journalled in an aperture within a yoke 82. On the upper surface of the yoke 82 is a recess 84 with two

bolt holes

85 and 86. This forms the terminal to receive another conductor which can be secured in the recess 34 by a suitable bracket or clamping plate secured against the conductor by bolts passing through the

apertures

85 and 86. As shown in FIGS. 2 and 5, the yoke 82 has spaced

arms

87 and 88 formed at their terminal ends with a pair of bosses 90 and 91. These bosses are identical in construction and the boss 91 has a threaded aperture 94. A pin 95 is threaded intermediate its ends at 96 and has an inwardly projecting cylindrical bearing surface 97 on its inner end. When the pin 95 is threaded into the threads 94 of the boss 91, it will project through a hearing 100 in one side of sleeve 101. Pin 95 can be secured in any adjusted position by set screw 93 in boss 91. Internally of the sleeve 101 and rotatable therein is a cylindrical portion 103 of the switch contact arm 29. This portion of the arm projects beyond the control arm 77 which is apertured at 105 to telescope over the end of the switch arm 29 and have a press fit so as to fix the bracket 77 against rotation on the arm 29. The projecting portion 103 of arm 29 is held in place within the sleeve 101 by a collar 106 secured by a screw 103 threaded into the collar 106 and projecting into the aperture 109 in the projecting end 103 of the switch arm.

Pin 95 also has a plane cylindrical end 111 which receives the collar 112 of insulating material. The end 111 surrounded by the sleeve 112 is received within the cylindrical aperture 114 of the boss which has a plug-like closure 116 secured in the boss by a pin 117 which is driven into a tight wedging engagement in the holes 118 in the boss 25 and through the plug hole 119 in the plug 116. Between the plug and the insulating collar 112 is a coil spring 121 which is compressed when in the assembled position shown in FIG. 4 so as to exert a pressure on the insulating sleeve 11?. to bias the arm 83 toward the sleeve 101. The pressure of the spring holds the end 97 of the pin inwardly of the sleeve 101 into engagement with the outside of the cylindrical extension 103 of the switch blade 29, thereby forming a good electrical connection between the end of pin 97 and the screw threaded connection 94 to the arm 88 of the yoke 32. Thus, the hinge connection is in part supported by bracket 11 and the hinge for the switch arm 29 is formed in part by the pin journalled in bearing in the sleeve 101. The electrical connection, however, is from the end of the pin 97 directly to the switch arm 29 and from there through the threaded

connection

94, 95 to the arm 63 of the yoke 82. If there is any wear between the end of the pin 97 and the portion 103 of the switch arm 29, the spring 121 will take up this wear by forcing the arm 30 inwardly so as to maintain high pressure between the end of the pin 97 and the cylindrical portion 103 of the switch arm 29. The fact that the arm 08 is fiexible permits its movement inwardly or outwardly in response to the action of the spring 121 or the movement of the tubular portion 103 of the switch arm 29.

The opposite hinge bearing is constructed in exactly the same way, the sleeve 101 has an opposite opening 126 axially aligned with the opening 100. The arm 87 terminates in a boss 90 which has a threaded hole 128 to receive the threaded portion 130 of a pin 131 which projects through the opening 126 far enough so that its end 132 is in firm sliding engagement with the portion 103 of the switch arm 29. Assembled on the end 134 of the pin 131 is an insulating sleeve 133, which is retained within the hollow boss 23 of the bracket 11, a spring 1 0 held in the hollow boss 23 by a plug 141 exerts pres sure against the adjacent end of the insulating collar 138, and this pressure is transmitted directly to the boss 90 of the flexible arm 87 carrying the pin 131 so that the pin is pressed against the outside of the tubular portion 103 of the switch arm 29. The plug 141 is suitably secured in place by a pin 142 projecting through hole 144; in the boss 23 and through the hole 146 in the plug 141. Pin 131 is held in adjusted position by set screw 92 in boss 90.

As will be clearly understood from the above detailed description, the hinging action of the contact arm 29 causes the sleeve 101 to be rotated on the ends of the

pins

95 and 131 so that it can be said that the portions of the pins 97 and 132 and apertures 100 and 126 form the mechanical hinge for the contact arm 29. Since the contact arm also rotates on its own axis during operation of the switch, the portion 103 turns in the sleeve 101 so that the internal surface of the sleeve 101 and the cylindrical tubular projection 103 on the switch arm 29 form the mechanical bearing for axial rotation of the contact arm 29. It will further be apparent that since the

arms

87 and 88 are flexible and are constantly urged toward one another by the action of the

springs

121 and 140, it will also be characteristic of the construction that the ends of the pins, indicated as 97 and 132, will be constantly urged toward one another because of the threaded engagement between these pins and the bosses and the ends of the two arms. In other words, the portion 103 of the switch arm 29 is the only structure which maintains the ends of the two pins separated. Since both springs 121 and are relatively powerful, there will then be a high unit pressure between the ends of the pins and the portion 103 of the contact arm 29. This high unit pressure between the ends of the pins and the tubular portion 103 assures that an excellent electrical connection is made at the ends of the pins with the portion 103. Both pins are tightly threaded into mating threads 94 and 128 in the ends of the

arms

88 and 87, and this, likewise,

insures a good electrical connection between the threads on each of the pins and the threads on each of the arms. If desired, sealing O-

rings

150 and 151 may be provided to protect the joint between the outside of the sleeve 101 and the inner face of the bosses 90 and 91. These rings would assure that the contact surfaces between the ends of the pins and the tubular part 103 of the contact arm 29 are protected against the intrusion of water and, therefore, the formation of ice. Likewise the O-

rings

150 and 151 would protect the threaded engagement between each pin and each arm from the intrusion of water to the inner screw threads 96 and 130 on the two pins even if the

collars

112 and 138 are damaged in some way. Ordinarily, the collars, when pressed against bosses 90 and 91, will be an effective seal, because

collars

112 and 138 are maintained in firm engagement under high pressure by the

respective springs

121 and 140. O-rings 152 and 153 protect the bearing surfaces between the portion of the switch arm 103 and sleeve 101. Thus, not only are all of the contact surfaces, which form portions of the low resistance electric conductive path concealed, but all are sealed from the intrusion of the elements. It is contemplated that in the smaller models of the switch it would be possible to make the

pins

95 and 131 an integral part of the

arms

87 and 88. In the smaller models, when so constructed, it would be possible to spread the arms far enough so as to receive the sleeve 101. The action of the pins, when formed integral, would be exactly the same as the action of the present device, where, although the pins are threaded into place in the ends of the arms, they are securely held therein against movement by the wedging action of the threads.

It is also characteristic of this device that the pins mounted in the

arms

87 and 88 form a single means for pivotally mounting the switch arm as well as conducting the current. Insulating collars 112. and 138 isolate the bracket 11 from the electrical conducting path. Since the bracket 11 is so isolated from the electrical conducting path, it can be constructed of less expensive material, such as malleable iron or cast iron. A substantial savings can be made by substituting less expensive materials of these kinds where a large number of parts are involved. Although the exterior surface of brackets constructed of less expensive material are subject to corrosion, nevertheless, the chance of corrosion internally of the two

bosses

23 and 25 is very unlikely in'view of the fact that the outside of each boss is sealed by tight plugs 116 and 141, respectively, and that the inside openings in the

bosses

23 and 25 of the bracket 11, of course, are sealed by the insulating

collars

112 and 138, respectively, which are held under the high spring pressure acting directly thereon. These sleeves cannot contract because they are on the ends of the pins which project internally of the sleeve so that spring pressure forces the sleeves outwardly into contact with the inner surface of each of the

bosses

23 and 25.

The mechanical operation of the switch, heretofore described, is not affected by the novel construction of the hinge herein used, and the opening and closing movements are effected by the crank 64 as it rotates in the same manner as in the patent to Froland, above mentioned.

Changes in and modifications of the construction described may be made without departing from the spirit of my invention or sacrificing its advantages.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In an electrical switch having a swinging and axially rotating contact arm, a contact surface connected to swing and rotate with said contact arm, a housing enclosing said contact surface, bearing means in said housing in which said contact arm is rotatable, and a stationary terminal for connection with a conductor, the combination of means in part forming a hinge and in part forming a low resistance electrical conductive path between said terminal and said switch arm comprising a pair of apertures in opposite sides of said housing, a. pair of spaced contacts connected with said stationary terminal and slidably received one in each of said pair 6 of apertures in said housing and means urging said contacts inwardly of said housing against said contact surface to produce high unit pressure between said oppositely facing contacts and said contact surface.

2. In an electrical switch having a swinging and axially rotating contact ann, a contact surface connected to swing and rotate with said arm, a housing enclosing said contact surface, bearing means in said housing in which said contact arm is rotatably fixed, and a stationary terminal for connection with a conductor, the combination of means in part forming a hinge and in part forming a low resistance electrical conductive path between said terminal and said switch arm comprising a pair of bearings in openings in opposite sides of said housing, a pair of spaced contacts connected with said stationary terminal, bearing surfaces on said contacts slidably and rotatably received one in each of said pair of hearings in said housing and means urging said contacts inwardly of said housing against said contact surface to produce high unit pressure between said oppositely facing contacts and said contact surface.

3. In an electric switch having a swinging and axially rotating contact arm, a contact surface connected to swing and rotate with said contact arm, a housing enclosing said contact surface, bearing means in said housing in which said contact arm is rotatable, and a. stationary terminal for connection with a conductor, the combination of means in part forming a hinge and in part forming a low resistance electrical conductive path between said terminal and said switch arm comprising a pair of cylindrical bearing surfaces opening through opposite sides of said housing, a pair of spaced contact pins connected with said stationary terminal and ro-tat ably and slidably received one in each of said pair of cylindrical bearings in said housing, a yoke having spaced resilient arms carrying said spaced contact pins and resiliently resisting separation of said contacts to produce high unit pressure between said oppositely facing contacts and said contact surface.

4. In an electric switch having a swinging and axially rotating contact arm, a contact surface connected to swing and rotate with said contact arm, a housing in the form of a cylindrical sleeve enclosing said contact surface and providing a bearing in which said contact arm is rotatable, spaced means on opposite sides of said contact surface for enclosing opposite ends of said sleeve, and a stationary terminal for connection with a conductor, the combination of means in part forming a hinge and in part forming a low resistance electrical conductive path between said terminal and said switch arm comprising a pair of cylindrical bearing surfaces opening in opposite sides of said housing to the interior of said sleeve, a pair of spaced contacts connected with said stationary terminal and projecting within said housing to engage said contact surface, and cylindrical bear-ing surfaces surrounding said contacts journalled in the said cylindrical bearings in opposite sides of said housing.

5. In an electric switch having a swinging and axially rotating contact arm, a contact surface connected to swing and to rotate with said contact arm, a housing enclosing said contact surface, bearing means in said housing in which said contact arm is rotatable, and a stationary terminal for connection with a conductor, the combination of means forming a combined hinge and low resistance electrical path between said contact arm and said stationary terminal including a pair of cylindrical bearings opening through opposite sides of said housing, a yoke connected with said stationary terminal at one end and having spaced resilient arms straddling said housing, and contact pins fixed in the ends of said arms and projecting through said bearing openings in opposite sides of said housing into contact with said contact surface to form the low resistance electric path between said stationary terminal and said blade, cylindrical bearing surfaces on said pins engaging with the pair of 7 cylindrical bearings opening in opposite sides of said housing to form the hinge, a stationary bracket with spaced arms carrying sockets axially aligned with each of said pins on opposite sides of said yoke and means in said sockets for pressing said arms of said yoke together.

6. In an electric switch having a swinging and axially rotating contact arm, a cylindrical contact surface on one end of said contact arm, a housing enclosing said cylindrical contact surface, bearing means in said housing in which said contact arm is rotatable, and a stationary terminal for connection with a conductor, the combination of means forming a hinge for said contact arm and a low resistance electrical conductive path between said terminal and said contact arm comprising a pair of cylindrical bearings opening through opposite sides of said housing around said cylindrical contact surface, a yoke connected with said stationary terminal at one end and having spaced resilient arms straddling said housing, contact pins fixed in the ends of said arms and projecting through said cylindrical bearings in opposite sides of said housing into contact with said contact surface to form the low resistance electric path between said stationary terminal and said contact arm, cylindrical bearing surfaces on said pins engaging the cylindrical bearing openings through said housing to form the hinge connection with said contact arm, a. stationary bracket with spaced arms carrying sockets axially aligned with each of said pins on opposite sides of said yoke, and means carried in said sockets into which said pins project for isolating said brackets from the low resistance conductive path between said stationary terminal and said contact arm.

7. In an electric switch having a swinging and axially rotating contact arm, a cylindrical contact surf-ace formed on one end of said contact arm, a housing enclosing said cylindrical contact surface, bearing means in said housing in which said contact arm is rotatable, and a stationary terminal or connection with a conductor, the combination of means forming a hinge and a low resistance electrical conductive path between said stationary terminal and said contact arm comprising a pair of cylindrical bearings opening through opposite sides of said housing on an axis at right angles to said contact arm,

a yoke connected with said stationary terminal at one end and having spaced resilient arms straddling said housing, and contact pins fixed in the ends of said arms and projecting through said bearing openings in opposite sides of said housing into contact with said contact surface to form the low resistance electric path between said stationary terminal and said contact arm, cylindrical surfaces on said pins slidable within the cylindrical bearings opening through opposite sides of said housing to form the hinge for the blade and a support for said hinge including a stationary bracket with spaced arms carrying sockets axially aligned with each of said pins on opposite sides of said yoke, insulated bushings in said sockets receiving the ends of said pins therein, plugs for closing the outer ends of said sockets and springs confined between said lugs and said bushings and urging said bushings against the outer surface of the arms of said yoke to produce high unit pressure between said oppositely facing contacts and said cylindrical contact surface.

8. In an electrical switch having an angularly movable contact arm, a contact surface connected to and rotatable with said contact arm, a housing enclosing said contact surface and forming a bearing support therefor for axial rotation of said contact arm, and a stationary terminal for connection with a conductor, the combination of a means forming a hinge for said contact arm and a low resistance electrical conducting connecting path between said stationary terminal and said movable contact arm, comprising a flexible support on said stationary terminal carrying a fixed contact, an opening in said housing through which said fixed con-tact extends into contact with said contact surface, an auxiliary fixed support on said switch and means acting between said flexible support and said fixed auxiliary support for producing high pres sure engagement between said fixed contact and said contact surface.

Bayer Sept. 9, 1952 Sciscione et a1. Sept. 24, 1957

Claims

1. IN AN ELECTRICAL SWITCH HAVING A SWINGING AND AXIALLY ROTATING CONTACT ARM, A CONTACT SURFACE CONNECTED TO SWING AND ROTATE WITH SAID CONTACT ARM, A HOUSING ENCLOSING SAID CONTACT SURFACE, BEARING MEANS IN SAID HOUSING IN WHICH SAID CONTACT ARM IS ROTATABLE, AND A STATIONARY TERMINAL FOR CONNECTION WITH A CONDUCTOR, THE COMBINATION OF MEANS IN PART FORMING A HINGE AND IN PART FORMING A LOW RESISTANCE ELECTRICAL CONDUCTIVE PATH BETWEEN SAID TERMINAL AND SAID SWITCH ARM COMPRISING A PAIR OF APERTURES IN OPPOSITE SIDES OF SAID HOUSING, A PAIR OF SPACED CONTACTS CONNECTED WITH SAID STATIONARY TERMINAL AND SLIDABLY RECEIVED ONE IN EACH OF SAID PAIR OF APERTURES IN SAID HOUSING AND MEANS URGING SAID CONTACTS INWARDLY OF SAID HOUSING AGAINST SAID CONTACT SURFACE TO PRODUCE HIGH UNIT PRESSURE BETWEEN SAID OPPOSITELY FACING CONTACTS AND SAID CONTACT SURFACE.