US3488752A

US3488752A - Switch construction

Info

Publication number: US3488752A
Application number: US689488A
Authority: US
Inventors: John W Burton; Asuncion Chung
Original assignee: HK Porter Co Inc
Current assignee: HK Porter Co Inc; G&W Electric Co
Priority date: 1967-12-11
Filing date: 1967-12-11
Publication date: 1970-01-06
Anticipated expiration: 1987-01-06

Description

Jan. 6, 1970 J. w. BURTON ETAL swncn CONSTRUCTION 2 Sheets-Sheet 1 Filed Dec. 11, 1967 a as Q Jan. 6, 1970 w aumou' ET AL 3,488,752

SWITCH CONSTRUCTION Filed Dec. 11, 1967 2 meets-Sheet z United States Patent 3,488,752 SWITCH CONSTRUCTION John W. Burton, Pittsburgh, Pa., and Asuncion Chung, Chicago, Ill., assignors to H. K. Porter Company, Inc., Chicago, III., a corporation of Delaware Filed Dec. 11, 1967, Ser. No. 689,488 Int. Cl. H01h 31/00 US. Cl. 200-48 7 Claims ABSTRACT OF THE DISCLOSURE Disconnecting switch for high tension electrical power installations having a switch blade pivoted for movement about an arc and rotatable about its own axis and characterized by a counterbalancing spring disposed on the centerline of the switch.

This invention relates to an improvement in disconnecting switches for high tension electrical power installations, particularly to air break switches of the type having a switch blade movable in an arc and rotatable about its own axis as shown in Patents 2,231,992, 2,527,924 and 3,174,004.

The improvement resides in an improved counterbalancing means for the blade of high capacity switches, i.e., high voltage, high current or a combination of the two, wherein the blade may extend up to to feet in length and employed in 230 kv. and 345 kv. and 1600 a., 2000 a., and 3000 a. categories, and even in installations employing 69 kv. 4000 a.

Heretofore, counterbalance for the blade of this type of switch has reside primarily in the provision of torsion springs associated with the hinge of the switch blade. These torsion springs are of necessity of large size and project outwardly from one or both sides of the switch structure thereby increasing the overall width of the switch structure.

According to the present invention, an in-line counterbalance is provided for the switch blade which does not increase the overall dimensions of the switch structure in any direction. The counterbalance assembly is characterized by a unitary casting including a cylindrical housing portion and comprising a combined frame, current carrying conductor and counter balance spring housing. By virtue of inclusion of the cylindrical portion directly in the casting comprising the frame of the switch, the counterbalance spring can be disposed within the interior of the frame structure and thus in line with the switch blade. Also, this unitary casting provides means whereby the stationary contact arms at the hinge or short end of the blade may be mounted in a position inverted from what is conventional and whereby the contact structure may be covered to protect the same from accumulation of ice in outdoor installations (a very serious problem in switches of the aforesaid heretofore general character).

Other objects and advantages of the present invention, its details of construction, arrangement of parts, and economies thereof, will be apparent from a consideration of the following specification and accompanying drawings, wherein FIG. 1 is a side elevational of the switch construction embodying the present invention.

FIG. 2 is a fragmentary side elevational view, partly in section of the switch construction illustrating its compression spring and its housing and the contiguous housing for the downwardly projecting contact arms, taken on the line 22 of FIG. 3.

FIG. 3 is a fragmentary plan View of the components illustrated in FIG. 2 and is essentially a section on the line 3--3 of FIG. 2.

Referring to the drawings, and particularly FIG. 1, the reference numeral 10 indicates a channel iron base that is mounted horizontally. It will be understood that the base 10 can be mounted vertically and that it can be mounted in an inverted position. However, for illustrative purpose, it is herein illustrated in a horizontal position with one set of contact arms projecting upwardly and the other downwardly as will be hereinafter further described. Accordingly, the words horizontal and vertical as used in the specification and claims with respect to axes of certain elements of the switch are to be considered to express certain relative positions of the axes with respect to each other since, while the words accurately identify the axes which are illustrated in the drawings, the vertical and horizontal positions might change if the switch of this invention were mounted other than in horizontal position shown.

The base carries

insulators

11, 12 and 13 which are of conventional construction and, as shown, may be of the pin type. The insulators 11 and 13 at ends of the base 10 are stationary. The intermediate insulator 12 is rotatable. For this purpose, a bearing 16 is mounted on the base 10 and as will appear hereinafter, constitutes the sole bearing support for the insulator 12. Shank 17 projects below the base 10 and is arranged to receive suitable crank means for rotating insulator 12.

The insulator 11 at its upper end carries a terminal bracket 18 and may be a bronze, copper or aluminum casting and it has a terminal pad 19 formed integrally therewith to which a terminal connector may be secured. Mounted on the terminal bracket 18 is a generally U- shaped stationary contact assembly comprising one or more pairs of opposed arms secured to a base member, all of hard drawn copper, bronze or aluminum or the like to provide small area, high pressure contact engaging surfaces or arms. One or more opposed pairs of arms 21 may be employed but in the illustration there are shown two pairs of arms spaced longitudinally of the blade portion 31 which will be hereinafter described. Reinforcing springs 22 serve to urge the arms of the contact members 21 toward each other to provide the required contact pressure against the terminal oblong portion 32 of blade 31 when the portion 32 is disposed transversely between an opposed pair of arms 21.

At its upper end the insulator 13 carries a support member 25 that may likewise be a bronze, copper or aluminum casting and has a terminal pad or portion 26 for receiving a terminal connector.

The frame support 25 carries a U-shaped contact assembly arm 28 which is of similar construction to the arrangement of contact arms 21 previously described except that it is inverted and is shown to comprise three pairs of contact arms adapted to receive a flattened shorter end blade portion 31' in the manner described with respect to the flattened, oblong portion 32 of blade 31. The arms of contact assembly 28 are formed so as to provide the desired small or contact engaging surfaces which are urged toward each other by reinforcing springs. The contact arms 28 are secured to the frame and housing support component 56 by the bolts 30. This contact arm housing 56 is integral with and contiguous to the tubular housing section 57 which in turn is supported and connected adjacent one end to and in conductive com munication with the support 25 on the insulator 13.

The U-shaped contact arm assemblies 21 and 28 are interconnected in the switch-closed position by the tubular switch blade comprising the elongated arm portion 31 and the relatively shorter arm portion 31, the

blade portions

31, 31 being suitably formed of hard drawn copper, bronze or aluminum.

The switch blade 31-31 is carried by a blade carriage 40 and which may be a casting of bronze or the like as a previously indicated, suitably machined to shape. The

carriage 40 is rotatably mounted in a blade hinge 44 which is mounted by bolts or studs 45 on contact arm housing component 56, as best shown in FIG. 3, to rotate about a horizontal axis through the longitudinal axes of the bolts 45.

In order to rotate the blade 31-31 about its longitudinal axis in the blade hinge 44 and also to swing the switch blade portions 31-31 to a vertical switch-open position the blade carriage 40 is provided with an arm 46 which extends angularly downwardly and rearwardly from the longitudinal axis of the switch blade 31-31.

As illustrated in FIGS. 1 and 2, the arm 46 extends on an angle from the blade carriage 40 and is journaled in a bearing portion 48 of a crank 49 which is secured to the rotatable insulator 12 and rotates therewith when the same is turned. As will be observed from FIGS. 1 and 2, the axis of the blade, the pivot axis of hinge 44, the axis of arm 46 in bearing 48 and the axis of rotation of the crank 49 all intersect in a common point.

When the insulator 12 is rotated from the position shown in FIGS. 1 and 2, the switch blade 31-31 will be rotated about its longitudinal axis to relieve the pressure between the contact surfaces at the edges of the oblong blade portions at the ends of sections 31-31 and the stationary arms of contacts 21 and 28. Simultaneously, the rotation of the insulator 12 and the crank pin 49 causes the switch blade portions 31-31 to swing about the horizontal axis common to the bolts 45. When the movement of the insulator 12 has been completed, the switch blade components 31-31 are moved to a fully open vertical position and the blade has rotated about its longitudinal axis.

The blade hinge 44 permits the switch blade to rotate about its longitudinal axis and is rockably mounted on the housing support component 56 about the horizontal axis of the bolts 45. Movement of the blade hinge 44 guides the switch blade in its arcuate movement from the switch-closed position shown in FIG. 1 to a vertical switch-open position and vice versa. Since the switch blade carriage 44 is fastened to the switch blade and its arm 46 is rotatably mounted in the bearing portion 48 of the crank pin 49, rotation of the insulator 12 about its vertical axis causes the crank pin 49 which is secured thereto to rotate about its vertical axis, and initially the switch blade 31-31 to rotate principally about its longitudinal axis and thereafter principally about the horizontal axis of the bolts 45.

When the insulator 12 is rotated in the reverse position the switch blade is swung to the switch-closed position. At the same time the switch blade is rotated about its longitudinal axis, its final rotation about this axis taking place as it approaches the horizontal position so that the final movement thereof into high pressure engagement with the contact blades 21 takes place while there is only a small amount of arcuate movement. This permits the necessary torque to be transmitted through the switch blade forrotating it in the switch-closed position with the contact surfaces under relatively high pressure.

The illustrated operating mechanism, to the .extent thus far described, is very similar to the operating mechanism of Patents 2,231,992, 2,527,924 and 3,174,004.

As previously indicated, heretofore counterbalance for the blade 31-31 has resided primarily in the provision of torsion springs associated with the hinge pins 45 of the switch blade, and were of necessity of large size, in proportion to the length of the switch blade 31. Further these projected outwardly from one or both sides of the switch thereby increasing the overall width of the structure.

In accordance with the present invention we provide an in-line counterbalance in the form of a compression spring 58 disposed in the cylindrical housing component 57. Here one end of spring 58 abuts against a base portion 59 of the housing 57. The outer end of spring 58 abuts against a movable spring support 60, the latter having secured thereto one end of a flexible cable 61. The

cable 61 extends through the spring 58 and through apertures in the base portion 59 of housing portion 57 and the adjacent housing portion 56 and is reaved around a guiding roller 62 and anchored at its opposite end to a cable support member 63 formed as part of the blade hinge 44. The roller 62, which is journalled on a shaft supported by the housing part 56 between the contact arms 28, and thus within the protective cover of the shield 64, serves to maintain a straight line path for the cable between the roller and the support 60, and at the same time permits the cable to extend forwardly in switchclosed position and upwardly in switch-open position, whereby to accommodate swinging movement of the blade without tangling of the cable 61, and sturdy compact counterbalancing spring arrangement.

The housing members 56-57 can be in the form of a unitary casting of conductive metal as previously described, which provides a strong frame for the switch, a direct conductive path between the pad 26 and the contacts 28, an in-line counterbalance which does not increase the switch size, and an enclosure for the spring 58 protecting it against impainment by moisture and ice formation. In a similar manner, the housing provides protective top covering for the inverted contact assembly 28, cable'61 and roller 62, and means for attachment of a corona shield 64. To stop the blades 31 at a desired open position such as 91, 92, etc., bolts 65 are used as adjustable blade stops against which the ribs 66 bump.

While we have shown and described the preferred embodiment of our invention, it will be understood by those skilled in the art that changes may be made in the details thereof without departing from its scope as comprehended by the following claims.

We claim:

1. A switch comprising an elongated switch blade pivotally mounted about a horizontal axis adjacent one end thereof to define a long blade portion and a relatively short blade portion and generally U-shaped stationary contact arms disposed adjacent each of the opposed ends of said blade, said blade being formed with oblong end portions and arcuately swingable into and out of disposition between said stationary arms, said blade being further pivotally mounted for rotation about its longitudinal axis to alternately dispose its oblong ends transversely of and into contact with said arms and upon reverse rotation to inclined position away from said arms, a counterbalance spring disposed and anchored adjacent to and rearwardly of said short blade portion and substantially in line therewith, flexible cable means extending therefrom over roller means disposed adjacent said short blade portion and anchored at its opposed end to a blade hinge movably mounting said blade at its long portion and fixed unitary frame means supported by an insulating mount disposed adjacent the short blade portion including upwardly closed mounting means for said short stationary contact arms and a conductive housing for said counterbalance spring.

2. The switch of claim 1 wherein the U-shaped contact arms adjacent the longer switch blade portion are adapted to project upwardly and the U-shaped contact arms adjacent the shorter switch blade portion to project downwardly when the switch is disposed horizontally.

3. The switch of claim 1 wherein the counterbalancing spring is disposed and anchored within a tubular housing portion and the U-shaped contact arms adjacent the short switch blade portion are disposed within a contiguous housing portion and project downwardly therein.

4. In a switch having a switch blade journalled in and pivotally mounted by a blade hinge for rotation about its axis and for arcuate swinging movement between a switch open and a switch closed position about a pivot defining long and short arms with flattened terminals, the improvement comprising a fixedly mounted electrically conductive frame pivotally supporting said blade hinge and including a housing portion defi ing a top closure for the short arm terminal aligned with the axis of the blade and a conductive cover extending therefrom to a fixed insu lator support, blade counterbalancing spring means in said latter housing portion in line with the axis of the blade, and flexible means aligned with the blade and the spring interconnecting said spring and said hinge and extending around medially disposed roller means.

5. In a switch as set forth in claim 4, said latter housing portion comprising a cylinder and said spring comprising a coil spring enclosed within said cylinder.

6. In a switch as set forth in claim 4, said roller being journalled on said frame between said housing portion and said hinge, said interconnecting means being flexible and wound about said roller.

7. In a switch as set forth in claim 4, said frame comprising, all in line with the blade, a terminal pad, a cylinder, an upwardly closed contact mounting portion and a pair of arms receiving and pivotally supporting said hinge, said spring comprising a coiled spring disposed Within said cylinder, a roller journalled in said contact mounting portion, said interconnecting means comprising a flexible cable extending from said spring about said roller to said hinge, and stationary contact means secured to said frame within said contact mounting portion and projecting downwardly for cooperation with the blade.

References Cited UNITED STATES PATENTS 9/ 1950 Schmidt. 5/ 1956 Hollander.