US2348015A - Electric switch - Google Patents

Description

May 2, 1944.

Fig.1.

V. L. MARES ELECTRIC SWITCH Filed May 20, 1941 25 Fig. 2,

45 5 5 3/ 47 E z q U 46;,

Inventor:

Virgil L. Mares,

His Attorney.

. ing movement to and from a Patented May 2, 1944 mums anaemic swrron VIII 1.. Mares,

New York Upper Darby, Pa., assignor to General Electric Company,

a corporation of Application May 29, 1941, Serial No. 39.4,312 Claims. (Cl. 200114) The present invention relates to electric switches and more particularly to improvements in construction of switches of the kind employable as disconnecting switching element or blade pivoted for swingclosed position between relatively stationary terminal contacts.

It is a common practice to provide some means iorlimiting or arresting the opening swinging movement of the switching element in such devices, and for holding the switching element in a predetermined position such as, for example, a position in which the switching element is-readily engageable by a switch hook or other operating tool for removal of the element from the switch support. Fixed solid stops are used for this purpose in some forms of disconnecting switch device. But if a switching element of considerable size or weight is employed, there may be danger of breakage of the switching element or its support if it is allowed to swing freely into engagement with a solid stop. The danger of breakage of the switching element by engagement with a solid stop likewise is present in the case of a disconnecting device employing a fused switching element wherein the fuse holder includes a casing constructed of glass, porcelain, or other frangible material.

It is one of the objects of the,present invention to provide, in a disconnecting switch support, a resilient bufier mechanism which is capable of arresting the movement of the switching element and of absorbing a considerable shock of impact without damage to the switching elementor the switch support.

In the case of a switching element pivotally mounted so as to be readily removable from its support, it has been found desirable to provide means for insuring a good contact between the pivoted end or the switching element and the adjacent stationary terminal structure. Spring biased contact means are sometimes provided but in general they exert a force against the switching element tending to move it in the open direction, which is undesirable for numerous rea sons. It is a further object of the present invention, therefore, to provide a new and lmproved mounting arrangement for discomiecting switch devices and the like which are pivoted at one end upon a terminal support and having means for insuring a good current conduc tive relation between the pivoted end of the switching element and the adjacent terminal without resulting in the imposition of an cut-= ward biasing force upon the switching element.

devices and having a It is a further object of the invention to pro vide an improved mounting arrangement for a switching element which is adapted to be pivotally and readily removably attached to a hinge support and having simplified means for preventing the removal of the switching element from its support except in the wide opened position thereof.

' Another object is the provision of an improved mounting arrangement for disconnecting switch devices and the like, which arrangement is of a simple, compact, and economical construction.

Other objects and the details of what I consider to be novel and my invention will become apparent from the following description and the claims appended, taken in connection with the accompanying drawing wherein, Fig. 1 shows in side elevation, an exemplary form of a disconnecting switch embodying my invention; Fig. 2 is an enlarged side elevation, partially in section, showing details of the hinge mechanism at the lower end of the device of Fig. 1; Fig. 3 is a view similar to Fig. 2 but showing the disconnecting swit'ch device in an opened position; Fig. 4 is a view in perspective illustrating further details in construction of certain parts of the structure.

As will be evident from the ensuing description, various features of the present invention are subject to modification and are suitable for employment in other forms of switch devices. Hence the embodiment shown in the drawing is tor purposes of illustration only. In this embodiment the fuse support includes two insula tors in and H disposed in spaced relationship and secured at one end to a suitable base (not shown). 0n the other end of the upper insulater it), there is supported a terminal and contact assembly including a terminal plate iii hav-- ing an upwardly projecting extension to which electric line conductors or leads may be secured by the clamping devices M. A contact it is rotatably supported upon a pin it carried by a bracket i'i mounted on terminal plate iii. Une or more springs ill serve to bias contact iii for rotation in a clockwise direction, as viewed in the drawing, and an adjustable stop screw it is provided in the lower end of the contact for limiting its rotation.

A flexible braided conductor 2?. insures good electrical connection between the contact iii and terminal plate it. The contact has two outwardly projecting arms one of which may he seen in drawing, for receiving therebetween in a latching engagement the upper end of the switching element i i,

buy the outer end of the lower insulator ii, there is mounted a terminal plate 25 which, similarly to terminal plate it, has an extension to which the line conductors or leads may be secured by clamping devices I4. The upper part of terminal plate 25 is adapted to serve as a hinge support and has two integrally formed bracket arms 28 disposed in horizontally spaced relation and having a hinge pin 21 extending therebetween. Secured to the upper end of the terminal plate 25 as by screws 28 is a deformable contact member such as relatively stiff leaf spring 29 which extends downwardly midway between the bracket arms 56 to a distance considerably below the hinge pin 2]. The greater length of the leaf spring 29 is spaced from the adjacent surface of the terminal 25 as indicated by the space 3!, while the lower end of the spring lies relatively close to a raised portion 32 on the surface of the terminal, plate.

The present invention may be embodied to advantage in switch supports for mounting of vari ous forms of switching elements or blades, and it is not intended therefore that the invention ice-limited to any one particular form of switching element or blade. However, the illustrated exemplary switch support is especially suited for the mounting of switching elements embodying fuse devices having cases constructed of glass, porcelain, or other frangible material. Such a fuse device is indicated at 24 onthe drawing. This fuse device may, for example, be of the form shown in the United States Patent 2,l88 816, issued January 30, 19%), to W. K. Rankin, and assigned to the General Electric Company, the assignee of the present invention. Fuse de vices of the form shown in the Rankin patent are of considerable size and weight, particularly when designed for high current interrupting ratings. They include a fusible element, and insulating support therefor, embedded in a body of sand or granular quartz which is contained in a tubular glass casing. Opposite ends of the glass casing are closed by metallic terminal ferrules 38 and 39, respectively, which serve for con nection of the fuse unit in an electric circuit.

For mounting the switching element or fuse device 24 on the previously described switch support, appropriate fittings are applied on the upper and lower ends, respectively, of the fuse device. The fitting onthe upper end of the fuse device comprises a metallic contact ring 4| clamped on the upper terminal ferrule 38 having suitable contact surfaces for engagement by complementary latching surfaces on the arms 23 of the upper pivoted contact I5. Secured to the ring 4| is an operating member 42' having an eye 43 for engagement by a common form of switch hook or operating tool. The upper terminal structure forms no part of the present invention and is of a type commonly known in the art such as is described in United States Letters Patent 2,275,831, granted March 10, 1942, and assigned to the same assignee as the present application.

The lower fitting comprises a metallic ring 45 clamped on the lower terminal 39 by means of bolts 46. This ring 45 has a rearwardly extending portion defining a hook 41 for cooperatively fitting over the hinge pin 27 and supporting the fuse device 24 thereon. The rear of the hook 41 is provided with a raised cam contact surface 78 at which is eccentric as regards the center of the hinge pin 21 so that in the open position of the switching element it is spaced from the leaf spring 29 but as the switching element is moved to the closed position, the cam contact surface 48 will wedge against the spring 28 forcing it backwardly toward the surface of the terminal plate 25. It will be observed that no outward rotational biasing force is thus imposed upon the fuse device 24 tending to move it in the opening direction, since the force of the leaf spring is substantially in a straight line between the terminal plate and the hinge pin, so that the cross section of the hook portion extending therebetween is merely under compression.

By means of the contact arrangement de scribed it will be observed that a good low resistance current conducting connection is made between the lower terminal and the lower end of the fuse device. The current will flow from the cam contact surface 48 of the hook through the leaf spring in opposite directions, both ends of which are in contact with the terminal plate 25. Since the current density through the leaf spring is thus reduced, the overall temperature of the spring is accordingly kept low so as to minimize the possibility of the spring becoming annealed due to running at too high a temperature and thus losing its spring properties. lit will be apparent that movement of the fuse device between the open and closed positions will result in a wiping action of the contacting surfaces to further insure a favorable current conducting relation therebetween.

The hook ll is provided with a relatively long end 51! which depends considerably below the hinge pin 21. If the switching element is moved to the opened position and permitted to swing ireely downwardly, the extremity of the hook will engage with the leaf spring 29 whereby the impact of the shock will be absorbed before the spring is forced back against the adjacent surface of the terminal plate. Thus it will be observed that the leaf spring serves a double funcoration.

What I claim as new and desire to secure b Letters Patent of the United States is: y

1. In an electric switch, a supporting structure having spaed terminals, 8, switching element disposed in a closed position between said terminals and pivoted adjacent one end on said structure so as to be swingable to an open position, a resilient member secured to said supporting structure for deformation relative thereto, a contact member for the pivoted end of said switching element engaging with and deforming said resilient member, and a member secured to the end of said switching element extending in opposed spaced relation to said resilient member so as to be engageable therewith as said switch ing element swings to the open position.

2. In an electric switch, a supporting structure having spaced terminal means, a switching element connected between said terminal means and pivoted for swinging movement to an open position, one of said terminal'means including a resilient contact member engaged and deformed by cooperative contact means on said switching element, and means secured to said switching element for engagement with said resilient contact member as said switxhing element is moved to the open position to arrest opening movement of said element.

3. In an electric switch, a supporting structure having spaced terminals, a switching element pivoted on said structure so as to be swingable to and from closed position between said terminals, one of said terminals including a leaf spring, a contact member provided on the pivoted end of said switching element for engaging with said leaf spring in the closed position of said element, said switching element having means arranged in opposed spaced relation to said leaf spring so as to be engageable therewith as said switching element swings to the open position.

4. In an electric switch, a supporting structure, a switching element pivoted thereon, spaced terminal means carried by said structure for cooperation with said switching element including a resilient contact member arranged for engagement with and deformation by contact means provided on said switching element, said resilient contact member maintaining pressure engagement with said contact means when said switching element is in closed position without biasing said switchin element in the opening direction, said switching element having means for engaging with said resilient contact member when said switching element swings to the open position" to arrest the movement thereof in the opening direction.

5. In an electric switch, a supporting structure having spaced terminals, 9. switching element pivoted on said structure so as to be swingable to and from closed position between said terminals, a spring secured to said terminal adjacent the pivoted end of said switching element, a cam contact on said switching element for engaging directly with said spring in the closed position of said switching element, and means on said switching'element to engage said spring as said switching element is moved to the open position whereby said spring is operative to absorb the shock of impact of said switching element.

6. In an electric switch including a supporting structure having spaced terminals, a switching element pivoted on one of said spaced terminals for swinging movement into and out of closed position between said terminals, a hook memher on said switching element, a hinge pin on said one spaced terminal adapted to be cooperatively engaged by said hook member, a spring member arranged on said one tel-mined adjacent said hinge pin, a cam contact surface on said hook member adapted to engage with said spring member in the closed position of said switching element.

7. In an electric switch, relatively stationary spaced terminals, a switching element for connection between said terminals, one of said ter minals including hinge means supporting said element for swinging movement into and. out of closed position between said terminals, said hinge means including a pair of spaced bracket arm and a hinge pin extending therebetween, hook means on said switching element for cooperatively fitting over said hinge pin,- said terminal having means defining a resilient contact surface adjacent said hinge pin, said hook mem= her having a cam contact surface adapted to engage with said resilient contact surface with a wiping action upon movement of said switching element to the closed position.

8. In an electric switch, relatively stationary spaced terminal means, a switching element for cooperation therewith, hinge means supporting said element for swinging movement into and out of connected position, said hinge means including a pair of hinge bracket arms disposed in spaced relationship, said switching element being supported by pivot means upon said bracket arms, a resilient deformable contact member forming part of one of said terminal means, a wedging contact forming a part of the pivot means of said switching element, said contact member being disposed generally between said bracket arms and engageable with a wiping action by said wedging contact as said switching element is moved to the closed position.

9. In an electric switch, a supporting structure having spaced terminal means, a switching element connected between said terminal means and pivoted for swinging movement to an open position, one of said terminal means including a resilient deformable metallic member, hinge means including a contact member for the piv-= oted end of said switching element, said resilient means arranged to serve the double function of completing a low resistance current conducting path with said contact member when the switching element is in the closed position and of absorbing the shock when the switching element swings to open position by engagement with a portion of said hinge means.

10. In an electric switch, a supporting structure including spaced terminals, a switching element for cooperation therewith, hinge means supporting said element for swingin movement into and out of connected position, said hinge meansv comprising a plate member forming a part of one of said terminals, a pair of bracket arms extending outwardly from said plate memher and having a hinge pin extending therebetween in a substantially parallel relation with respect to the adjacent surface of said plate member, hook means on said switching element for cooperatively and removably fitting over said hinge pin, said hook means having a substantially straight end extending in such a direction as regards the longitudinal axis of said switching element so as to preclude movement of said hook from said hinge pin except in a predetermined opened position of said switching element.

* VIRGIL L. MARES.

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