US3627939A

US3627939A - Electric switch

Info

Publication number: US3627939A
Application number: US47733A
Authority: US
Inventors: John Howard Myers
Original assignee: KEARNEY NATIONAL CANADA Ltd
Current assignee: KEARNEY NATIONAL CANADA Ltd
Priority date: 1970-06-19
Filing date: 1970-06-19
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14
Also published as: CA912623A

Abstract

An electrical switch includes a pivotable switch blade having finger contact means carried thereby and an elongated contact associated with at least one of the terminals to engage and deflect the finger in the switch-closed position. In addition, the blade may be pivoted at one end and when so pivoted is provided with finger contact means which engage the pivot to provide electrical contact between the terminal and the pivot pin.

Description

Unied States Patent John Howard Myers Guelph, Ontario, Canada June 19, 1970 Dec. 14, 19711 Kearney-National (Canada) Limited Guelph, Ontario, Canada lnventor Appl. No. Filed Patented Assignee ELECTRIC SWITCH 14 Claims, 6 Drawing Figs.

us. on zoo/4a lint. c1 non. 21/28 Field of Search 200/48, 48

R, 43 P, 48 SB, 48 148,163,170 A [56] References Cited UNITED STATES PATENTS 2,894,101 7/1959 Lindell et a1 200/48 SB 2,174,237 9/1939 Crabbs 200/163 FOREIGN PATENTS 1,210,318 3/1960 France 200/163 Primary Examiner-Herman J. Hohauser An0mey-Gordon Waldie ABSTRACT: An electrical switch includes a pivotable switch blade having finger contact means carried thereby and an elongated contact associated with at least one of the terminals to engage and deflect the finger in the switch-closed position.

In addition, the blade may be pivoted at one end and when so pivoted is provided with finger contact means which engage the pivot to provide electrical contact between the terminal and the pivot pin.

PATENTED DEC 1 4 I97! SHEET 1 [IF 3 ELECTRIC swircn The present invention relates to electrical switches, more particularly to electrical switches for high-voltage use.

Disconnect switches used for the distribution and transmission of electric power are available in difierent forms. Such switches include terminals and a switch blade which establishes and disestablishes the circuit between the terminals. Switches generally are constructed for movement of the blade in a horizontal orvertical plane into and out of the switch closed position. Further, a number of switches may be grouped for simultaneous operation. Additionally, switches may be constructed to have two breaks between the terminals. Also, switches have been designed for operation byan operator using a long insulated stick equipped with a special prong to actuate the switch.

In these prior art switches, current transfer at the break is achieved employing jaw contacts associated with a terminal and a mating end of the blade, generally a flattened portion of a tubular blade. In single-break switches, the blade is hinged at the other terminal, and many different forms of current transfer at this hinge end have been adopted.

In double-break switches including a single blade, the blade is commonly mounted at its mid point for pivotal movement into the gap between spaced apart jaw contacts associated with each terminal, followedby rotational movement to engage the spade ends of the blade with the jaws. This type of operation requires the use of a complicated mechanism to achieve both the pivotal and rotational movements.

In both single-break and double-break switches, if the blade or the jaw contacts become worn or burned it is necessary to completely replace them.

The present invention seeks to overcome the aforementioned disadvantages of disconnect switches. In accordance with one embodiment of the present invention, an elongated contact member is associated with at least one of the terminals and resilient finger contact means, generally in the form of jaw contacts, is associated with and carried by the contact blade to engage and be deflected by the elongated contact member in the switch closed position.

In the switches, where the blade is pivoted at one of the terminals, in accordance with another embodiment of the invention, a pivot pin, insulated from the blade at its passage through the surfaces of the blade and in electrical contact with the terminal, is engaged by and deflects a resilient finger contact means, generally in the form of jaw contacts, the finger contact means being carried by and in electrical contact with the blade, so that electrical contact between the pin and the blade is achieved.

The invention is further described with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of one form of the switch of the present invention;

FIG. 2 is a partially exploded closeup of part of one end of the switch blade of FIG. 1;

FIG. 3 is a perspective view of a second form of the present invention;

FIG. 4 is an exploded view of the terminals of FIG. 3;

FIG. 5 is a perspective view of a third form of the invention; and

FIG. 6 is a partially exploded closeup of part of one end of the switch blade of FIG. 5.

Referring to FIGS. 1 and 2, a disconnect switch 10 includes two

terminals

12 and 14 and a switch blade 16. Switch blade 16 has an elongated hollow body of generally square cross section and is constructed from electrically conductive material. A first pair of resilient finger contact elements 18 in the form of jaws are located internally of the blade 16 adjacent one end thereof. A second pair of resilient finger contact elements 20 also in the form of jaws are located internally of the blade 16 adjacent the other end thereof and positioned at 90 to the first jaws Ill. As may be more clearly seen in FIG. 2, each pair of

finger contact elements

18 and 20 consists of two fingers constructed of inwardly bent resilient material including a Iongitudinal slit 22. The fingers are affixed to the blade in any convenient manner, such as by rivets 24. Alternatively. the fingers may be in the form shown in FIG. 6 discussed below.

Elongated openings 26 are located in opposite walls of the blade 16 adjacent the first jaws 18.

An elongated cylindrical contact pin 28 having a tapered free end is mounted on a plate 30 fixed to terminal 12. Openings 32 are located in opposite walls of blade 16 adjacent the second jaws 20. A pivot pin 34 mounted on terminal 14 passes through an insulating bushing 35 constructed of insulating material, such as, nylon, and then through openings 32 and a further insulating bushing 37 and is engaged by the second jaws 20.

In this way, the pivot pin 34 is insulated by the

bushings

35 and 37 from the blade as it passes through the surfaces of the hollow body. Insulation of the pin 34 from the blade is necessary to prevent arcing and burning. Electrical contact between the terminal 14 and the blade 16 is achieved by contact between the jaws 20 and the pivot pin 34.

The openings 32 are generally round and of sufficient diameter to allow the pivot pin 34 to pass through the bushings surrounding the openings. The openings 32 also may be of the same shape as openings 26.

As blade 16 pivots about pivot pin 34 and moves in a horizontal plane into the switch-closed position, the pin 28 passes through one of the openings 26 and engages and deflects the first jaws l8, and passes out through the other opening 26. The openings 26 may be of any convenient size or shape, provided that they are large enough to allow the pin 28 to pass therethrough. They are preferably elongated as illustrated.

Buses or

cables

36 and 38 lead into

terminals

12 and 14 respectively. The buses are joined to the terminals by

plates

40 and 42 secured together and about the buses by bolts 44. The construction of the terminals is discussed more fully below in relation to FIG. 4.

Terminal 12 is insulated from the earth by a fixed insulator shown schematically at 46. Terminal 14 is insulated from the earth by a rotatable insulator shown schematically at 48. The insulator 48 is affixed to the blade through flanges 50 so that upon rotation of the insulator 48 such as by actuation with handle 52 the blade 16 is rotated about the pivot pin 34.

Insulators

46 and 48 may be mounted on a lboxlike section 53.

In the embodiment of FIG. 3, a disconnect switch includes two

terminals

112 and 114 and a switch blade 116. Switch blade 116 has a hollow generally square cross section body and is constructed from conductive material. Each end of the blade 116 is identical and includes a pair of resilient finger contact elements 118 in the form of jaws attached to the interior of the blade such as by rivets 120. Each jaw is constructed as shown in FIG. 2.

Elongated openings 122 are located in opposite walls of the blade 116 adjacent each jaw 118. Openings 122 may be of any convenient shape as discussed above with reference to openings 26 of FIG. 1. The blade is mounted for pivotal movement in the horizontal plane by means of flanges 124 attached to the blade 116 and also to a rotatable insulator shown schematically at 126.

Elongated cylindrical contact pins 128 and 130 having tapered free ends are associated with one with each of

terminals

112 and 114 and project in opposite directions. Pin 128 is mounted on a plate 132 fixed to the terminal 112 in a manner described below in more detaiLSimilarly, pin 130 is mounted on a plate 134 fixed to the terminal 114.

Buses or

cables

136 and 138 lead into

terminals

112 and 114 respectively and are joined to the terminals in a manner described below. Terminal 112 is insulated from the earth by an insulator shown schematically at 140, and terminal 114 is insulated from the earth by an insulator shown schematically at 142. The insulators may be mounted on a boxlike section 143.

The switch of FIG. 3 is shown in its open position. Upon rotation of insulator 126, such as by actuation with handle 144, the blade 1 16 moves in a horizontal plane so that the jaws engage and are deflected by the

pins

128 and 130 thereby achieving the switch-closed position.

Each of

terminals

112 and 114 are shown in exploded view in FIG. 4. The terminal 12 in FIG. 1 is of similar construction. The terminal 112 is described, but it will be understood that

terminals

12 and 114 are of identical construction. Terminal 112 consists of a bracket member 146 which is affixed to the insulator 140, such as by bolts 148. Bolts 148 pass through elongated slots 150 which enable the bracket to be moved relative to the insulator 140. Pin 128 is fixed to plate 132 and projects through opening 152 in bracket 146. Plate 132 is secured to bracket 146 by bolts 154 passing throughopenings 156 in bracket 146 and intoscrew-threaded openings 158 in plate 132. Four such openings 158 are provided in plate 132 so that the plate 132 may be secured to the bracket 146 in two alternative positions.

Two

additional plates

160 and 162 are provided to secure the bus 136 to the terminal. Each of these plates are provided with crossed grooves 164 in the face. The bus 136 may sit in one of the grooves in each plate and thereby be readily located relative to the terminal 112. The structure is held together by bolts 166 passing through openings 168 in bracket 146, openings 170 in plate 132, openings 172 in plate 160 and openings 174 in plate 162. A retaining unit 176 is threaded on the free end of the bolt I66.

Referring now to FIG. 5, a disconnect switch 210 includes two

terminals

212 and 214 and a switch blade 216. Blade 216 has an elongated hollow body of square cross section and is constructed of conductive material. The blade is mounted for pivotal movement in a vertical plane.

A first pair of resilient contact fingers 218 in the form of jaws is provided, each member of which projects inwardly at the end of the blade 216 and engages an elongated contact pin 220 afiixed to the terminal 212. Contact 220 has a tapered free end and deflects the jaws 218 while in the switch-closed position illustrated. Elongated openings 222 on opposite sides of the blade, only one of which is shown, allow the contact 220 to project through the blade in the switch-closed position. The shape of the openings 222 may be of any convenient shape as indicated above with reference to openings 26 of FIG. I. The construction of this end of the blade 216 is more clearly seen in FIG. 6. The jaws 218 are attached to the blade such as by rivets 223. Alternatively, the jaws may be in the form shown in FIG. 1.

I A second pair of resilient contact fingers 224, in the form of jaws, is provided at 90 to the first jaws at the opposite end of the blade 216. The fingers 224 project inwardly of the blade 216 and engage a pivot pin 226 horizontally located with reference to terminal 214 by mounting in upwardly projecting arms 228 of the terminal 214. Pivot pin 226 passes through openings 230 located in opposite sides of the blade 216.

The pivot pin 226 is insulated from the hollow body of the blade 216 at the openings 230', i.e. at the points of passage through the surface thereof. The pivot pin is, however, in electrical contact with the terminal 214 and electrical contact between the terminal 214 and the blade 216 is achieved through the contact of the jaws 224 with the pivot pin.

A releasable catch 232 is located adjacent the terminal 212 and is pivoted about pin 234 located in a bracket 235 attached to the upper surface of the blade 216. The catch 232 includes two

arms

236 and 238. Arm 236 projects horizontally and includes a flat end 240 which is adapted to engage the outer extremity of pin 220 during disengagement of the switch. Arm 238 projects vertically and includes a hooklike end 242 adapted to engage a stop 244 on a rod 245 attached to terminal 212 to secure the catch 232 when the switch is in the closed position illustrated. A spring 246 associated with the pivot 234 normally urges the catch to the position illustrated. The stop 244 represents the point of maximum downward movement of the blade 216.

The catch 232 includes an opening 248 to receive an actuating handle whereby the switch 210 may be opened. Upon pulling catch 232 with an actuating handle approximately horizontally of the switch, the catch 232 pivots about pin 234 and end 240 engages the outer end of pin 220 while simultaneously end 242 is released from stop 244. Upon continued pulling, the blade 216 pivots in a vertical plane about pin 226 and the fingers 218 become disengaged from pin 220 and hence the switch becomes open.

The invention has been described above with reference to a blade which is a hollow elongated tube of square cross section. Such a tube allows the blade to be formed readily by extrusion. The blade may have any convenient shape, provided that the resilient finger contacts are mounted on the blade.

In this connection, the blade may be of rectangular cross section, or be constructed of two channels arranged into a square or rectangle. Alternatively, the blade may be constituted by a round tube having squared ends. Further, special end portions may be provided on tubes, bars or channels.

The resilient finger contacts engaging the elongated contact are shown adjacent the free end or ends of the blade. Such contacts may be provided at any convenient location along the length of the blade, but it is preferred that the finger contacts be located at the ends.

The finger contacts engaging the elongated contact have been illustrated in two different forms in FIGS. 1 and 5. Many alternative forms are possible. While it is preferred to use two opposed contacts forming a jaw to engage the contact pins, a single finger carried by the switch blade may be used to contact the pins. Similarly, where the fingers engage a pivot pin, a single resilient finger may be employed.

The contact or contacts may be integrally formed with the blade. The fingers generally are constructed of different conductive material from the blade, although these components may be formed of the same material. Generally, the blade is constructed of aluminum, while the fingers are formed of silver-coated copper.

In the forms illustrated in FIGS. 1 to 6, the fingers are formed of inherently resilient material. They may alternatively be formed of nonresilient material, the required resiliency being provided by auxiliary springs.

The fixed elongated contact has been illustrated with a tapered end. This is to facilitate deflection of the fingers by the pin to establish contact between the members. However, such taper may be omitted, if desired.

The elongated contact member is illustrated as a cylindrical solid pin. The contact may also be of tubular construction. Further, alternative shapes may be employed, for example, square, rectangular and oval.

In FIGS. 1 and 5, at the hinge end of the blade, the electrical contact and the mechanical hinges are provided by a single set of components in accordance with the second embodiment of the invention. This may be modified-to provide such operations by separate components. For example, a simple hinge pin may be employed to provide the mechanical hinge and conventional current transfer means may be employed to electrically join the blade and the terminal.

A plurality of switches according to the invention may be employed for simultaneous operation. For example, three such switches may be used together for three-phase operation. In addition, a centerbreak may be provided. In this structure, two switch blades, each pivoted about a terminal engage a fixed central contact to achieve the switch-closed position. In such a structure, two blades mounted for pivotal movement, such as in FIG. 1, about two terminals may engage a fixed contact having oppositely projecting contact pins.

The switch of the present invention may be combined with commonly used auxiliary devices, such as, are restrictors, ground switches. load brake devices and are interrupters.

The switches of the present invention may be used in a variety of applications over a wide range of current ratings and voltages. For example, the switches operate satisfactorily at current ratings from 600 to 3,000 amps and at voltages from 15 to 230 kv., using different sized fingers, blades and contacts.

The present invention, therefore, provides switches having unique and advantageous features as compared to the conventional type of switch.

As indicated above, the pin 128 (FIG. 1) and hence pins 28, 130 and 220 which are similar, may be moved with relation to the jaws. This movement may be rotational or horizontal. This allows the pin to be moved to a position so that fresh contact surfaces on both the pin and the jaws may engage if the original contact surfaces become worn or burned. Further, in accordance with the preferred illustrated forms of the invention, when the pin and/or contact surfaces become completely worn, they may be simply replaced without the need to replace the whole switch.

in a conventional switch of the structure described above, when the contacts become worn or burned, it is not possible to expose new surfaces, or readily replace the contacts. In conventional switches, it is generally necessary to replace the whole blade and one terminal. Clearly, the present invention provides advantages over these prior art switches.

Further, in prior art switches of the same current rating, but different modes of operation, different types of contacts are employed. in contrast, the switches of the present invention, for the same current rating, may employ the same contacts. Thus, the structure of H6. 1 may be modified to operate in the vertical plane without any necessity to change the form of the pin 28 and the contacts 13 other than to rotate them through 90.

In the structure of H6. 3, the blade l 116 is mounted for rotation about its approximate midpoint into its closed position. In prior art double-ended switches, as mentioned previously, it is common practice to provide pivotal movement of blade ends into a jaw, followed by rotation of the blade ends into contact with the jaw members. The present invention has eliminated the need for such complicated movements and the equipment necessary to achieve such movements.

The construction of the hinge end of the switch blade in the structures of FlGS. l and 5 is similar to or may be identical with, other than rotation through 90, that at the free or contact end of the blade. The provision of a single pivot and electrical contact mechanism is clearly superior to the prior art where the operations are provided by separate mechanisms.

As in the case of the first embodiment, for the same current rating, the same construction may be employed for different types of switches. Thus, the structure of FIG. 5 may be modified to operate in the horizontal plane without any necessity to change the form of the pivot pin 226 or the fingers 224, other than rotation through 90. This is in complete contrast with the prior art where different mechanisms to provide pivotal movement and electrical connection are used for different types of switches.

it is readily apparent that switches including both embodiments of the invention, as in FlGS. l and 5, are superior to the prior art switches due to their universal usage, ease of manufacture and ready servicing.

Modifications are possible within the scope of the invention.

1 claim:

1. An electrical switch including first'and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switchclosed position wherein said two terminals are connected through said blade, said switch blade having an elongated hollow body of generally square cross section, an elongated contact member associated with said first terminal, said blade being pivoted at one end thereof about said second terminal, and resilient finger contact means comprising inherently resilient jaw contact means carried by said blade and located internally of said hollow body and adjacent the other end thereof, said hollow body including opposed openings adjacent said jaw contact means whereby said elongated contact member may pass through said hollow body and engage and deflect said jaw contact means in said switch-closed position.

2. The switch of claim ll wherein said elongated contact member is capable of limited rotational and translational motion.

3. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch open position wherein said two terminals are not connected through said blade and a switchclosed position wherein said two terminals are connected through said blade, two elongated contact members associated one with each of said first and second terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being positioned to engage and be deflected by said elongated contact members when said blade is in its switch closed position, said blade having an elongated hollow body of generally square cross section.

4. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switchclosed position wherein said two terminals are connected through said blade, two elongated contact members associated one with each of said first and second terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being positioned to engage and be deflected by said elongated contact members when said blade is in its switch closed position, said finger contact means comprising a jaw contact means located adjacent each end of said blade, said blade being mounted for pivotal movement about the approximate midpoint of its length.

5. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switchclosed position wherein said two terminals are connected through said blade, said blade having; an elongated body of generally square cross section two elongated contact members associated one with each of said first anti second terminals, and resilient finger contact means comprising jaw contact means carried by said blade and located internally of said body adjacent each end of said blade, said hollow body including opposed openings adjacent each of said jaw contact means whereby said elongated contact members may pass through said hollow body and engage and deflect said jaw contact means in switch-closed position, said blade being mounted for pivotal movement about the approximate midpoint of its length.

6. An electrical switch including first and second terminals, an electrically conductive switch blade mounted at one end thereof for pivotal movement about said second terminal between a switch-open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, an elongated contact member associated with said first terminal, first resilient finger contact means associated with and carried by said blade, said first finger contact means being positioned to engage and be deflected by said elongated contact member when said blade is in said switch-closed position, said blade being mounted for pivotal movement by means of a pin passing through a hollow portion of said blade, said pin being electrically insulated from said blade, at its points of passage through the surface thereof, said pivot pin being connected to and in electrical contact with said second terminal, said blade carrying and having associated therewith second resilient finger contact means, said second resilient finger contact means being in electrical contact with said blade and being positioned to engage and be deflected by said pivot pin whereby electrical communication between said second terminal and said blade is established.

7. The switch of claim 6 wherein said first resilient finger contact means comprises first inherently resilient jaw contact means located at the end of said blade remote from said one end.

8. The switch of claim 7 wherein said second resilient finger contact means comprises second inherently resilient jaw contact means located adjacent said one end of said blade.

9. The switch of claim 8 wherein said switch blade has an elongated hollow body of generally square cross section, and said first and second jaw contact means, are located internally of said hollow body, said hollow body including opposed openings adjacent both said first and second jaw contact means whereby said elongated contact means may pass through said hollow body and engage and deflect said first jaw contact means in said switch-closed position, and whereby said pivot pin may pass through said hollow body and engage and deflect said second jaw contact means.

10. The switch of claim 9 including releasable latch means.

11. An electrical switch including first and second terminals, an electrically conductive switch blade mounted by means including a pivot pin for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a swtich-closed position wherein said two terminals are connected through said blade, said blade being hollow at least in the region of said pin, said pivot pin being electrically insulated from said blade at its points of passage through the surface of said hollow region but connected to and in electrical contact with one of said terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being in electrical contact with said blade and being positioned to engage and be deflected by said pivot pin whereby electrical communication between said second tenninal and said blade is established.

12. The switch of claim 11 wherein said resilient finger contact means comprises jaw contact means.

13. The switch of claim 11 wherein said switch has an elongated hollow body of generally square cross section.

14. The switch of claim 11 wherein said switch blade has an elongated hollow body of generally square cross section, said finger contact means comprises inherently resilient jaw contact means located internally of said hollow body and adjacent one end thereof, said hollow body including opposed openings adjacent said jaw contact means whereby said pivot pin may pass through said hollow body and engage and deflect said jaw contact means.

i l i l

Claims

1. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, said switch blade having an elongated hollow body of generally square cross section, an elongated contact member associated with said first terminal, said blade being pivoted at one end thereof about said second terminal, and resilient finger contact means comprising inherently resilient jaw contact means carried by said blade and located internally of said hollow body and adjacent the other end thereof, said hollow body including opposed openings adjacent said jaw contact means whereby said elongated contact member may pass through said hollow body and engage and deflect said jaw contact means in said switch-closed position.

2. The switch of claim 1 wherein said elongated contact member is capable of limited rotational and translational motion.

3. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, two elongated contact members associated one with each of said first and second terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being positioned to engage and be deflected by said elongated contact members when said blade is in its switch closed position, said blade having an elongated hollow body of generally square cross section.

4. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, two elongated contact members associated one with each of said first and second terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being positioned to engage and be deflected by said elongated contact members when said blade is in its switch closed position, said finger contact means comprising a jaw contact means located adjacent each end of said blade, said blade being mounted for pivotal movement about the approximate midpoint of its length.

5. An electrical switch including first and second terminals, an electrically conductive switch blade mounted for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, said blade having an elongated body of generally square cross-section, two elongated contact members associated one with each of said first and second terminals, and resilient finger contact means comprising jaw contact means carried by said blade and located internally of said body adjacent each end of said blade, said hollow body including opposed openings adjacent each of said jaw contact means whereby said elongated contact members may pass through said hollow body and engage and deflect said jaw contact means in switch-closed position, said blade being mounted for pivotal movement about the approximate midpoint of its length.

10. The switch of claim 9 including releasable latch means.

11. An electrical switch including first and second terminals, an electrically conductive switch blade mounted by means including a pivot pin for pivotal movement between a switch-open position wherein said two terminals are not connected through said blade and a switch-closed position wherein said two terminals are connected through said blade, said blade being hollow at least in the region of said pin, said pivot pin being electrically insulated from said blade at its points of passage through the surface of said hollow region but connected to and in electrical contact with one of said terminals, resilient finger contact means associated with and carried by said blade, said finger contact means being in electrical contact with said blade and being positioned to engage and be deflected by said pivot pin whereby electrical communication between said second terminal and said blade is established.