US3806687A - Toggle and latch mechanism for switches - Google Patents

Abstract

A high-voltage switch comprising a fixed jaw contact and a switch blade assembly. The fixed latch-contact element includes a contact member and a projecting latching tongue and the switch blade assembly comprises a pair of spaced, parallel switch blades adapted to pivot into and out of electrical contact with the contact member. The switch blades are biased towards each other so as to exert sufficient pressure on the contact member for high amperage operation when the switch is closed. A toggle mechanism is provided between the switch blades which, upon actuation by the movement of an operating lever, urges the opposed switch blades apart to reduce the pressure between the blades and the contact member during opening and closing. The tongue formed on the latch-contact element cooperates with the toggle mechanism which latches to it to provide positive locking between the closed switch blade assembly and the fixed latch-contact element.

Description

United States Patent [191 Teschner 1 Apr. 23, 1974 Robert W. Teschner, Atlanta, Ga.

[73] Assignee: Gulton lndustries, lnc., Metuchen,

Sept. 15, 1972 [75] Inventor:

[22] Filed:

[21] Appl. No.: 289,463

{52] [1.8; CI .200/321, 200/170 A, 200/249, 200/244 [51] lnt.-Cl. H01h 3/20 [58] Field of Search 200/170 A, 48 KB, 169 R, 200/48 R [56] References Cited UNITED STATES PATENTS 2,809,244 10/1957 Owens et a]. 200/169 R X 3,193,632 7/1965 Sprague ZOO/169R X 3,335,236 8/1967 McCloud ZOO/169R X 3,183,335 5/1965 Cobbett 200/170 A 3,064,107 11/1962 Date ZOO/170 A Primary Examiner-Robert K. Schaefer Assistant Examiner-William J. Smith Attorney, Agent, or Firm-Darby & Darby ABSTRACT A high-voltage switch comprising; a fixed jaw contact and a switch blade assembly. The fixed latch-contact element includes a contact member and a projecting latching tongue and the switch blade assembly comprises a pair of spaced, parallel switch blades adapted to pivot into and out of electrical contact with the I contact member. The switch blades are biased towards each other so as to exert sufficient pressure on the contact member for high amperage operation when -the switch is closed. A toggle mechanism is provided between the switch blades which, upon actuation by the movement of an operating lever, urges the opposed switch blades apart to reduce the pressure between the blades and the contact member during opening and closing. The tongue formed on the latchcontact element cooperates with the toggle mechanism which latches to it to provide positive locking between the closed switch blade assembly and the fixed latch-contact element.

6 Claims, 6 Drawing Figures BACKGROUND OF THE INVENTION This invention relates generally to high-voltage switches, and more particularly to contact and contact latching structures for high voltage disconnect switches. t

In order to maintain electrical contact between the fixed and a movable contact of a switch operating under high amperage conditions, a sufficiently high pressure must be maintained between the surfaces of the two contacts. However, it is undesirable to maintain this high contact pressure during opening and closing of the switch, since the contacts will tend to become scored or deformed clue to the movement of the contacts against each other. Further, opening and closing of the switch may be difficult. For these reasons, in disconnect switches utilizing movable switch blade assemblies comprising a pair of spaced, parallel switch blades, various apparatus have heretofore been provided for prying the switch blades apart during opening and closing to relieve pressure from the contacts during the switch closing (and opening) operation and then to re-apply high pressure only after the switch has been closed.

Additionally, prior art high-voltage disconnect switches are usually mounted at elevated positions for safety reasons. Such switches are opened and closed from the ground by the use of hook sticks whose ends are inserted into appropriate openings provided in the pivotal blade assembly and then exerting a force on the blade assembly in a particular direction depending on whether the switch is to be opened or closed. In the past, it frequently happens that the switch is inadver- 1 tently opened through the mishandling of such hook sticks or, alternatively, dueto momentary current overloads due to circuit faults. Positive latching apparatus is desirable to prevent such occurrence.

SUMMARY OF THE INVENTION Accordingly, one object of this invention is to provide new and improved contact and contact-latching structure for high-voltage switches.

Another object of the present invention is to provide a disconnect switch having positive latching apparatus with a mechanism for spreading the opposed pivotal switch blades during opening and closing of the switch to prevent deforming the contacts.

Still another object of the present invention is to provide a mechanism having the dual function of urging opposed switch blades apart during opening and closing of the switch and positively latching the movable contact to the fixed contact when the switch is closed.

Briefly, in accordance with the preferred embodiments of the invention, these and other objects are attained by providing a high-voltage disconnect switch having a fixed latch-contact element and a pivotally mounted switch blade assembly. A toggle mechanism provided on the free end of the switch blade assembly is coupled to an operating lever having a hook ring formed at one end receivable of the end of a hook stick. The toggle mechanism has links formed with latching shoulders adapted to cooperate with a tongue projecting from the support of the latch-contact element. Upon closing the switch, the toggle mechanism is actuated by exerting a force on the operating lever thereby urging the opposed switch blades apart to relieve pressure between these blades and the fixed contact. Further, upon closing, the latching shoulders formed on the toggle mechanism engage the end of the tongue. Similarly, upon opening the switch, the toggle mechanism is actuated, relieving the contact pressure and disengaging the shoulders from the tongue.

DESCRIPTION OF THE DRAWINGS A better understanding of the invention will be attained by referring to the following detailed description in conjunction with the drawings in which: 1

FIG. 1 is a side elevational view of the switch of the present invention;

FIG; 2 is a front elevational view of the switch of the present invention;

FIG. 3 is a perspective view of the latch-contact ele ment of the present invention;

F IG. 4 is a detailed front view of the latch-contact element and switch blade assembly when the switch is closed;

FIG. 5 is a sectional view taken along line 5--5 of FIG. 4; and

FIG. 6 is a perspective view of the toggle mechanism of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1, a switch generally denoted as 10 is illustrated. Switch 10 is supported by a base 12 on which a pair of vertically spaced horizontally extending insulator stacks 14 and 16 are rigidly mounted. The lower insulator stack 16 has a hinge contact 18 fixed on its right end as seen in FIG. 1, while the upper insulator stack 14 has a latch-contact element 20 described in greater detail below fixed on its free end. Both hinge contact 18 and latch-contact element 20 are provided with vertically directed respective extensions 22 and 24, having bores formed therein for subsequent connection to conventional electrically conducting bus bars 15 and 17.

A switch blade assembly 26 is pivotally connected to hinge contact 18. Switch blade assembly 26 includes a pair of spaced, parallel switch blades 28 and 30 formed of a suitable conductive metallic material. The blades are spaced from each other by a pair of spacer rods 32 positioned approximately midway along the length of the switch blade assembly. A lower end portion of each switch blade 28, 30 overlies a respective one of a pair of contact ears 34 and 36 integrally formed with hinge contact 18. A bolt 38 extends through aligned openings formed in the contact ears and the switch blades and is retained at this position by conventional means, such as by a nut 40. Each contact ear 34, 36 includes a horizontally extending projection 42 formed on its lower half which is adapted to interfere with a detent rod 44 when the switch is opened, thereby limiting the movement of the switch blade to an approximately horizontal position when fully opened.

Turning now to FIG. 3, the latch-contact element 20 is preferably formed as a casting including a support 46 holding a pair of contact members 48 and 50. Each contact member 48, 50 comprises a rectangular plate having a uniform width defined by a pair of opposed,

vertical contact surfaces 52 and 54. A latching tongue 56 is provided above contact member 48 and projects perpendicularly from a boss 57 formed on base 46 of the jaw assembly substantially parallel to the contact members 48, 50. The latching tongue 56 comprises an elongate shank 58 having one end integral with boss 57 and a pair of oppositely extending locking lugs 60 formed at its free end. Each arm 60 may have an inwardly facing corner beveled as shown at 62. The length of each blade-spacer pin 32 is essentially equal to the distance between the opposed contact surfaces 52 and 54 formed on each contact member 48, 50, so that upon pivoting the switch blade assembly 26 into the position shown in FIGS. 1 and 2, the contact members 48 and 50 will be received between the opposed switch blades with the contact surfaces 52 and 54 engaging the inner surfaces of the switch blades. When the switch blade assembly is pivotted to its closed position the edge of an upper portion of each blade 28, engages a stop 47 formed on base 46 to prevent further movement in the closing direction by the switch blade assembly.

As mentioned above, under high amperage operating conditions it is necessary to have a sufficiently high contact between the inner contact surface of each switch blade 28, 30 and the mating contact surface 52 or 54 of the respective contact members 48 and 50. In order to assure such pressure, a bolt 63 is provided within aligned openings in the switch blades so as to be positioned between the contact members when the switch is closed as best seen in FIG. 4. A portion of the shank of bolt 63 extends beyond switch blade 30 and has a compression spring 64 whose ends abut against the outer surface of switch blade 30 and a cup-shaped retainer 66. A nut 68 is threaded over the outer end of bolt 63 and bears against retainer 66 thereby fixing the amount of compression of the spring 64. Thus, by adjusting the position of nut 68, the amount of pressure and the separation between the opposed switch blades may be adjusted. In order to provide sufficient contact pressure between switch blades 28 and 30 and contact surfaces 52 and 54, nut 68 is positioned so as to urge the switch blades towards each other and decrease the distance between them to a value slightly less than the distance separating the pairs of contact surfaces 52 and 54. Beveled surfaces 70 are formed on each contact member so that when the switch blades move into contact with these surfaces the blades are urged apart against the pressure of spring 64, thereby facilitating the closing of the switch. Pressure between the contacts is provided by spring 64 which has been compressed during the closing operation.

As mentioned above, the invention has objects, among others, of both relieving the pressure along the mating contact surfaces during opening and closing of the switch and also providing a positive latching between the fixed and movable contacts. In order to achieve these objects, a toggle mechanism, generally denoted 72, is provided between the switch blades 28 and 30 which mechanism, upon actuation by a hookstick-operated lever, both forces the switch blades apart and also latches them onto the fixed latch-contact element.

Referring to FIGS. 4, 5 and 6, the toggle mechanism 72 comprises a pair of toggle links 74. Each link 74 is substantially L-shaped comprising legs 76 and 78 integrally joined at a corner portion 80. The free end of each leg 76 is pivoted to the corresponding end of the leg 76 of the other link by a rivet 84 or by other conventional means. Switch blades 28 and 30 are provided with inwardly facing bifurcated ears 86 and 88 respectively to which the toggle links 74 are pivoted at their corner portions by pins 89. A vertical shoulder 90 is formed at the free end of each link leg 78 by a protrusion formed in the leg.

A hook ring lever 92 (seen in FIGS. 1 and 4) is pivotally mounted at the top of the switch blade assembly on a shaft 94 extending between the switch blades and suitably retained in position, as by retaining rings 96. The hook ring lever 92 is formed with a rigid shank 98 connecting a ring 100 (FIG. I) at one end to a hub and pusher portion 102 which extends to a point immediately behind the point where legs 76 of the toggle mechanism links are pivotally connected. A spring 104 is provided around shaft 94 which biases lever 92 to its furthesmost counterclockwise position (as shown in FIG. 1), such furthestmost position being limited by horizontally extending shoulders 106 formed on the lever hub and adapted to limit lever movement by co-- operating engagement with the end surface of each switch blade.

In the operation of switch 10, from an open position, the switch blade assembly is rotated counterclockwise in the direction of arrow 108 in FIG. 1, by a hook stick whose end has been inserted in ring 100. Immediately before the ends of the contact members 48 and 50 are engaged by the inner surfaces of switch blades 28 and 30, a downward force is exerted on the hook stick causing the operating lever to rotate in a clockwise direction relative to the switch blade assembly as viewed in FIG. 1. The lever rotation is translated to the pusher portion 102 of the lever 92 which engages the pivoted joint of the toggle mechanism at P in FIG. 5, thereby pushing it in the direction shown by arrow 110. Such action causes the toggle mechanism to exert an outward force on each switch blade in a manner known in the art, thereby causing the switch blades in the vicinity of the toggle mechanism to move a limited distance away from each other with switch blade 30 moving against the force of spring 64 in a manner described above. As a result of this operation, the blades are spread, apart and the otherwise substantial contact pressure between the inner surfaces of the switch blades and the contact surfaces 52 and 54 of the fixed contact members is relieved during closing of the switch.

The actuation of the operating lever 92 also causes the free end of legs 78 of the toggle links to move away from each other. The toggle mechanism is so positioned that upon closing the switch, the latching tongue 56 is in an immediately opposed relationship to the toggle mechanism. With the toggle mechanism actuated, i.e. in an open configuration, the lugs 60 of tongue 56 are received within the area between spread-apart legs 78 of the toggle mechanism. When the switch is fully closed, the pushing force of the hook stick on ring 100 is terminated, the the stick removed. The lever 92 under the force of spring 104 then returns to its normal position, thereby allowing the toggle mechanism to resume its normal configuration under the force of the normal resiliency of the switch blades in addition to action of spring 64. By so doing, the shoulders 90 on the ends of legs 78 move into opposed relationship to the inner surface of the lugs 60. Thus, the toggle mechanism and, consequently, the switch blade assembly is positively latched onto the jaw assembly by virtue of the cooperation between the toggle mechanism and tongue56. A similar, but reverse procedure, is followed upon opening the switch. The end of a hook stick is inserted into ring 100 and a force is exerted on lever 92 which is moved in a clockwise direction as seen in FIG. 1, thereby spreading the switch blades and the link ends with latching shoulders 90 apart in a manner similar to the procedure discussed above. Thus, the positive latch is broken while the substantial contact pressure is relieved during the opening operation. The beveled surfaces 62 on lugs 60 act as cam surfaces once the shoulders 90 are moved a sufficient outward distance to engage them upon opening the switch. Thus, the cooperation of shoulders 90 and beveled surfaces 62 aids in opening the toggle mechanism during the switch opening operation. It should be noted that should the blade assembly be inadvertently rotated too far in the close direction, the free end of tongue 56 contacts the pivoted joint of the toggle mechanism exerting a force L, (FIG. 5) on the mechanism. This force tends to further close the toggle mechanism increasing the integrity of the latched connection in'addition to the contact pressure.

Thus, the object of relieving contact pressure during opening and closing of the switch and providing a positive latching capability to the switch is achieved by pro viding the novel toggle and latch-contact element. The considerable scoring or deforming of the contact surfaces and blades is eliminated. Of course, only a preferred embodiment has been illustrated, and other equivalent structure may be utilized within the scope of the present invention as defined by the claims.

What is claimed is:

1. An electrical switch comprising:

a fixed contact-latch element including at least one contact member having a pair of spaced, parallel contact surfaces;

a pivotally mounted switch blade assembly including a pair of spaced parallel switch blades adapted to swing into and out of electrical contact with said contact surfaces;

means normally biasing said switch blades towards each other for applying substantial pressure be tween each switch blade and its mating contact surface when said switch is in closed position;

unitary toggle means provided on the switch blade assembly for both moving said switch blades apart during opening and closing of the switch to relieve the pressure thereof on the contact surfaces and for selectively locking said switch blade assembly in closed position.

2. A switch according to claim 1, wherein said unitary toggle means includes a pair of toggle links, each link being pivotally connected to a respective switch blade and pivotally connected to the other toggle link, said switch further including operating means for selectively exerting an opening force on said unitary toggle means to spread said switch blades.

3. The switch according to claim 2, wherein each of said toggle links is substantially L-shaped, comprising a pair of legs joined together at a corner, each link being pivoted to a respective switch blade at its corner and having one leg pivoted to the correspondingleg of the other link.

4. An electrical switch comprising:

a fixed latch-contact element including at least one contact member having spaced, parallel contact surfaces and a rigid projecting tongue substantially adjacent to said contact memlber; pivotally mounted switch blade assembly including a pair of spaced parallel switch blades adapted to move into and out of electrical contact with said contact surfaces; and toggle mechanism including a pair of substantially L-shaped links, each including first and second legs joined at a corner, the first leg of each link being pivotally connected at its outer end to the first leg of the other link, the corner of each link being pivoted to a respective blade, and the second leg of each link having a shoulder formed at its end adapted to engage said tongue in closed position of said switch, said toggle mechanism being selectively operable to move said switch blades apart during opening and closing of the switch to relieve the pressure exerted by the switch blades on said contact surfaces and also being selectively operable to latch onto said tongue when the switch is closed and to release said tongue upon opening the switch.

5. The switch according to claim 6, wherein the tongue is defined by a pair of latching members projecting substantially perpendicularly therefrom, each latching member being adapted to engage a respective shoulder when the switch is in closed position.

6. The switch of claim 6 further including an operating lever pivoted between said switch blades, said operating lever having a shank portion extending adjacent to the toggle mechanism pivot connection and adapted to contact said toggle mechanism when the lever is pivoted from its normal position to a depressed position, to exert a force on the toggle mechanism to cause the toggle mechanism to urge the blades apart and to latch onto said tongue.

Claims (6)

1. An electrical switch comprising: a fixed contact-latch element including at least one contact member having a pair of spaced, parallel contact surfaces; a pivotally mounted switch blade assembly including a pair of spaced parallel switch blades adapted to swing into and out of electrical contact with said contact surfaces; means normally biasing said switch blades towards each other for applying substantial pressure between each switch blade and its mating contact surface when said switch is in closed position; unitary toggle means provided on the switch blade assembly for both moving said switch blades apart during opening and closing of the switch to relieve the pressure thereof on the contact surfaces and for selectively locking said switch blade assembly in closed position.

2. A switch according to claim 1, wherein said unitary toggle means includes a pair of toggle links, each link being pivotally connected to a respective switch blade and pivotally connected to the other toggle link, said switch further including operating means for selectively exerting an opening force on said unitary toggle means to spread said switch blades.

3. The switch according to claim 2, wherein each of said toggle links is substantially L-shaped, comprising a pair of legs joined together at a corner, each link being pivoted to a respective switch blade at its corner and having one leg pivoted to the corresponding leg of the other link.

4. An electrical switch comprising: a fixed latch-contact element including at least one contact member having spaced, parallel contact surfaces and a rigid projecting tongue substantially adjacent to said contact member; a pivotally mounted switch blade assembly including a pair of spaced parallel switch blades adapted to move into and out of electrical contact with said contact surfaces; and a toggle mechanism including a pair of substantially L-shaped links, each including first and second legs joined at a corner, the first leg of each link being pivotally connected at its outer end to the first leg of the other link, the corner of each link being pivoted to a respective blade, and the second leg of each link having a shoulder formed at its end adapted to engage said tongue in closed position of said switch, said toggle mechanism being selectively operable to move said switch blades apart during opening and closing of the switch to relieve the pressure exerted by the switch blades on said contact surfaces and also being selectively operable to latch onto said tongue when the switch is closed and to release said tongue upon opening the switch.

5. The switch according to claim 6, wherein the tongue is defined by a pair of latching members projecting substantially perpendicularly therefrom, each latching member being adapted to engage a respective shoulder when the switch is in closed position.

6. The switch of claim 6 further including an operating lever pivoted between said switch blades, said operating lever having a shank portion extending adjacent to the toggle mechanism pivot connection and adapted to contact said toggle mechanism when the lever is pivoted from its normal position to a depressed position, to exert a force on the toggle mechanism to cause the toggle mechanism to urge the blades apart and to latch onto sAid tongue.

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