US1894543A - Electric switch - Google Patents

Description

Jan. 17, 1933. ROWE 1,894,543

ELECTRIC SWITCH Filed Sept. 15, 1931 2 Sheets-Sheet 1 Fig. .l

so 32 2s 9 INVENTOR Ra gafin onJM Rowe,

Jan. 17, 1933. RQWE' 1,894,543

ELECTRIC SWITCH Filed Sept. 15, 1931 2 Sheets-Sheet 2 INVENTOR REIYZ/DQO dlv. owe,

ATT6NE raremeu Jan. 17, 1933 UNITED STATES PATENT OFFICE RAYMOND N. ROWE, OF PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TRUMBULL ELECTRIC MANUFACTURING COMPANY PORATION OF CONNECTICUT OF PLAINVILLE, CONNECTICUT, A COR- ELEC'IRIC SWITCH Application filed September 15, 1931.

My invention relates to electric switches of the class which are usually enclosed in a protective casing provided with an external operating handle and are commonly used for controlling power or lighting circuits.

Switches of this class are described more in detail in the co-pending application, Serial No. 469,152 which was filed July 19, 1930 by Herman J. Hammerly.

My present invention applies particularly to the combination of a specific form of loosely mounted movable roller contact and a pair of stationary contacts having resilient contact fingers arranged for bridging or connecting engagement by the movable roller contact.

A particular object of my invention is to provide a switch construction including a pair or pairs of stationarycontacts and a loosely mounted freely rotatable movable roller contact member having its axis parallel with the opposed faces of a pair of stationary contacts and being movable into and out of connecting engagement with the pair of stationary contacts.

Another object is to provide a switchconstruction including a pair of stationary contacts arranged with opposed contact faces and a freely rotatable cylindrical movable contact member for electrically connecting the pair of stationary contacts and consisting of a substantial roller or cylinder of metal (preferably copper) and having its axis parallel with the contact faces of the opposed stationary contacts.

Another object is to provide a switch construction as described in the preceding paragraph and in which the contact roller or cylinder is freely mounted in an insulating carrier, the carrier having a portion adapted to move into interposed position between the stationary contacts as the cylinder is moved out of contacting position.

Another object is to provide an insulating mounting or support for a cylindrical contact of the character described. the mounting being movable between a pair of stationary-contacts and having projecting ribs along its corner edges which are arranged to slide in corresponding grooves in the base of the Serial No. 582,927.

stationary contacts with its axis parallel withthe faces of the stationary contacts and freely rotatable so that, in its normal operative movement, any pitting or roughening of either the roller or the stationary contacts due to arcing, will tend to rotate the roller so as topresent a new contact making surface.

nother object is to provide a switch construction including a movable contact which is of a substantially cylindrical form and composed of a sufiicient mass of metal to possess a high thermal capacity which, combined with its rotating movement, assists greatly in disrupting the arc caused by the opening of the switch while under load.

Another object of the present invention is to increase the life and efficiency of a switch of this character.

Another object is to provide a construction of this character in which the contacts may be readily inspected.

Another object is to provide a construction of this character in which it is practically impossible for the'movable switch member to be jammed.

Another object is to provide a rugged construction of this character in which the contacts are certain to engage properly even if the insulating support is warped and even if the stationary contacts arev not accurately aligned.

Another object is to provide a switch of this character which can be operated either by quick make and break mechanism or by a simple crank action.

In carrying out the invention I provide an insulating base which supports a pair of relatively stationary contacts having resilientcontact fingers and in this base I mount a movable slide or plunger carrying a roller switch member which is arranged for a bridging or connecting engagement between the contact fingers. The base is provided with a passage or perforation and the stationary fingers so as to quench any are which tends to form. The roller is loosely carried by the plunger with its axis approximately parallel with the opposed faces of the stationary contacts.

Fig. 1 is a plan view of a single unit embodylng one form of my invent on.

Fig. 2 is a longitudinal sectlonal view of the device of Fig. 1, showing the parts in the closed circuit position.

Fig. 3 is a perspective view showing a switch of this character in dotted lines within a receptacle. I

Fig. 4 is a front view of a switch embodying a pair of assembled units, one of winch is shown in artial section.

Fig. 5 1s a perspective view 'of one of the contact rollers on a larger scale.

Fig. 6 is an edge view of the insulatmg carrien' Fig. 7 is a perspective view of a modified form of movable switch member partly in section.

In the form shown the insulating base preferably has two elevated portions 7 and 8 connected by side flanges 9.and 10 and with a perforation or passage 11 extending entirely through the body from front to rear.

The stationary contacts are preferably.

formed of resilient metal having feet 12 and 13, respectively, mounted on the supports 7 and 8 and secured in place by one or more screws such as 14 and 15. These contacts are provided with resilient fingers 16 and. 17 which are preferably inclined slightly and project slightly into the passage 11. These contact fingers are connected to the respective supporting feet by arched portions 18 and 19 which are located in recesses 20 and 21 at opposite sides of the passage 11.

The movable switch member consists of a contact element 22 in the form of a roller and a carrier lunger 23 formed of insulating material. T is plunger is shaped in cross section to loosely fit the passage 11 and the contact roller 22 is of such a diameter asto be tightly gripped by the contact fingers 16 and 17 when it is forced into contact making position between the fingers, and is preferably of a length slightly longer than the width of the contact fingers.

The carrier plunger may be made in any suitable manner, for instance, it may be built up of the cross portions 24 and 25 and the side plates 26 and secured together in any suitable manner.

The rear end of the portion 24 may be concave so as to bring its edges closer to the sides of the contact roller 22 and assist in holding the roller in its central position. The parts, however, should-be of such dimensions as to support the contact roller loosely so as to permit it to adjust itself to the active surfaces 'of the contact fingers 16 and 17 and thus afford a more perfect electrical connection.

The insulating body is preferably provided with interior ribs or flanges such as 30 and 31 on opposite sides of each of the stationary contact fingers and the flanges 32 and 33 of the movable switch member overlap the flanges 30 and 31 so as to more closely confine any are and prevent it from spreading sideways. The insulating carrier with its flanges or ribs eoact-ing with the flanges or ribs in the body serves to block the path of the are both from face to face and from edge to edge of the stationary contacts.

As the movable contact member 22 is freely rotatable it is continually presenting a fresh surface of contact to the stationary contact fingers and any pitting or roughening of either the stationary or movable contacts will tend to accelerate the rotation of the roller and present new contact making surface.

This switch construction can be mounted in anysuitable manner, for instance, within a receptacle 35 of any suitable type, having a cover 36.

The switch may be actuated in any suitable manner as, for instance, by means of a-crank shaft-37 with an external handle 38. This crank shaft may be engaged in an open slot 39 in'the' sideplates 26 for convenience in assembly and operation.

The switch is operated by movement of the handle 38 or other suitable actuating device. To close the circuit, carrier 23 is moved outwardly so as to force the contact roller 22 between the resilient contact fingers 16 and 17. To open the circuit the carrier is thrust in the opposite direction and the insulating barrier 24 is-immediately interposed between the contact fingers 16 and 17 as soon as the roller'22 is disengaged. The action of the spring fingers is to propel the contact 22 away from them as the circuit is being opened because of the cylindrical character of the roller contact. i

This roller may .beformed of any suitable material and may-in fact be hollow as shown at 22' in Fig. 5. The member should. however, be sufficiently rugged and have sufficient mass of metal to withstand the mechanical action and to prevent undue heating when in In the form of movable switch member sesame ried by the pivot pin 40. The pin can be fast in the roller and loose in the side plates 26 or tight in the side plates and loose in the roller so as to permit the roller to adapt itself to the Contact fingers.

Although I have shown a simple type of one-piece crank shaft and handle, it should be understood that such a switch may be acill tuated by a quick make and break mechanism, for instance, of the type shown and described in the Hammerly applications 519,328 and 519,329, filed March 2, 1931.

It will be seen that in this type of construction no hinged, soldered or riveted connections are required and that the switch unit is compact and rugged. The movable contact construction draws a large proportion of the arc into a closed chamber which is formed within the molded base. The balance of the arc is blown outward through the passage and completely quenched.

It has been proven by actual tests and experiments that a switch having roller contacts of the type disclosed herein has a decidedly greater circuit breaking capacity than one in which the movable contact is of the knife blade or brush type and engages the stationary contacts with a mere sliding or wiping movement.

Obviously the details of my construction, such as the cross-section of the insulating slide or the manner of securing the roller contact in position in the slide, may be varied to a considerable extent without departing from the spirit of my invention.

I claim:

1. A switch including a molded insulating base having a passage therethrough, statlonary contacts mounted in the base at opposite sides of said passage, an insulating carrier slidable through said passage and having an opening, and a loosely mounted contact roller 1 carried by said carrier in said opening and adapted to be interposed between said stationary contacts.

2. An electric switch construction including an insulating base having a perforation therethrough, contacts mounted on the outer surface of the base with resilient fingers on opposite sides of said perforation, an insulattact roller loosely mounted between said plates and between said barriers.

4-. In an electric switch an insulating base having a passage extending therethrough, resilient contacts mounted on said base on opposite sides of said passage, an insulating plunger slidable in said passage and consistmg of side plates and an interposed insulating barrier, said barrier being interposed between the contacts in the open circuit position of the switch and a rotatable switch member having a supporting shaft mounted in the side plates of the plunger, said rotatable member being adapted to be interposed between the contacts to close the circuit and means for operating said plunger.

5. In an electric switch an insulating base having a passage therein, stationary resilient contacts supported by the base on opposite sides of said passage, an insulating plunger slidable in said passage and consisting of SldB plates and interposed barriers, a switch roller contact loosel supported between the side plates and the arriers to co-act with said stationary contacts, one of said barriers being adapted to be interposed between the stationary contacts when the arts of the switch are in the open circuit position.

6. In an electric switch an insulatin base having a passage extending therein su stan plates.

RAYMOND N. ROWE.

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