US1185141A - Knife-switch. - Google Patents

Description

H. F. STARRETT. KNIFE SWITCH.

APPLICATIIOM FILED MAY 13. I912. 1,185,141. 1 Patented May30, 1916.

Lid/676w? Tdfirreff cation for HENRY F. STAB-BETT, OF CHICAGO, ILLINOIS.

KNIFE-SWITCH.

Specification of Letters Patent.

Application filed May 13, 1912. Serial No. 696,925.

the accompanying drawing, forming a part.

of this specification.

My invention relates to improvements in knife switches, and particularly to knife switches adapted for use in connection with panel boards.

It has for one of its objects to provide a knife switch which may be removably mounted on the front of the panel board and in whiehthe securing means may be readily accessible from the front of the switch.

My invention is particularly designed for use in connection with the panel board base member shown and described in an appli- June 13, 1911, Serial No. 632,883.

For the purpose of disclosing my invention 1 have illustrated one embodiment thereof in the accompanying drawings, in whichv Figure 1 is a. side elevation, partly in section, of a knife switch embodying my invention; Fig. 2 is a. front elevation of the switch; Fig. 3 is a detail section taken on the line of Fig. 1; Fig. 4: is a plan view of a blank from which the clips are adapted to be formed; Fig. 5 is a perspective view of one of the bracket clips; and Fig. 6 is a perspective view of one.ofthe anchor studs of the panel board base member.

The switchillustrated in the accompanying drawings is shown mounted upon a panel board having the characteristics as disclosed in the above-mentioned application. I have not illustrated in detail this panel board, as the same forms no part of the present invention, but have shown sufficient of the panel board to illustrate the manner of mounting the switch This panel board base member comprises an insulating base 1 which may be of slate'or other usual material, and on the backof the panel board are mounted the bus bars (not shown) and connector bars-2. These bus bars and cnnector bars form the distributing conductors mounted on the rear of the base and are permanently secured in position by means of U. 8. Letters Patent filed by me anchor studs. with a flat head 4: adapted to engage the front face of the base and has its stem arranged to extend through an opening in the base and through one-of-the connector bars or bus bars, as the case may be. The ends of the stem are swaged over, asat 6, and covered by solder to make a firm electrical and mechanical contact w'th the distributing conductor. In the front face of the anchor stud a screw-threaded socket is provided for receivingthe screw by means of which the clips of the switch are secured in position.

The knife switch comprises a pair of bracket clips 7, a pair of contact clips 8 and a pair of knife blades 9. Each blade is pivotally mounted between the arms of the bracket clips and the front ends of the blades are connected together by a suitable insulating'handle 10 in which the front ends-are adapted to be embedded. The bracket. clips and contact clips are of the same general construction, being'changed merely in slight details to adapt them io their different functions. l lach clip comprises a base 11 having a longitudinal extension 12 in which is formed the opening 13 to permit the securing screw 1 to pass therethrough and engage in the.screw-threaded socket in the anchor stud and a pair of spring arms or fingers 15 integrally wardly from the base 11. These arms are sprung toward each other at their upper ends to closely engage the knife blades and are provided with longitudinally extending bracing webs 16 which connect thein with the extension 12 of the base. The arms of the bracket clips are provided with openings 17 through which extend the rivets 18 upon which are pivoted the rear ends of the knife blades 9, a spring washer 19 being interposed between oine of the heads of the rivets and one of the arms of the bracket clips to assist in making a close electrical contact between the arms and the knife blade.

The base of the clip has a pair of downwardly extending projections 20, preferably formed by punching up the metal, which projections are arranged to engage in a transverse slot 21 formed in the head of the anchor stud to prevent ing on the stud.

The contact clips, as before stated, are of the same construction as the bracket clips, withthe exception that they are vided with the opening to receive not prothe pivot Patented May 30.. 1916.

Each anchor stud is provided formed with and bent upthe clips from turnrivet and are provided witl. stop 2 preferably formed by striking up the metal. at the proper point, which limit the downward movement of the knife blades. The tops of the arms are also flared outwardly to assist in guiding the knife blades between the arms.

In forming the clips I preferably form the same from a blank, such as is shown in Fig. 4. This blank, as illustrated, is formed from a thin strip of material having at its central portion a rearward extension Eefore the blank is bent, the opening for receiving the securing screw is formed there in, the lugs 20 are struck up therein, and if the blank is to form a bracket clip the open ings for the pivot rivet 18 are formed, and if the blank is for a contact clip the lugs 21 arestruck up. The blank is then bent up along lines extending inside the outer ends of the projection 22, so that when the arms are turned up that portion of the lug 22 turned up therewith forms the webs 1.6.

By theprovision of the offset base or longitudinal extension of the base, I am enabled to so locate theopening through which the securing screw passes that access may be readily obtained thereto from the front by a screw driver, so that the securing screw may be fastened in position from the front of the clip. In ordinary practice it is impossible to secure the clip of a knife blade switch in position due to the fact that the spring arms are so close together that a screw driver could not be inserted between them, but by my arrangement, while I have not sacrificed anything in strength, I have provided a means whereby access may be had to the se curing screw from the front. Furthermore,

by the provision of the bracing webs danger of side strain breaking the dina-l extension of the base is prever these bracing webs additionally the spring arms and give then an ado clamping action.

While I have shown. and described form of switch in. which my invention bodied, it will be understood that changes may be made in the switch and that the invention may be embodi other forms of knife switches witheu parting from the spirt of my invention set forth in the appended. claim.

rlaving thus described my invention, wit 1 claim as new and desire to secure by Le ters Patent, is i The combination with an insulating base, of an anchor stud extending therethroupfl and permanently fastened thereon havin screw-threaded recess in the front face th of and a transversely extending slot across the front face thereof, a knife switch clip secured to said stud and comprising a bottom having an extension in which the holding screw opening is formed, downwardly ex- 6 tending alined projections on either side of said opening engaging in the slot with their anchor stud to prevent the clip from turning when securedto said stud, and integral upwardly extending spaced apart spring arms on said bottoi In witness whereof, I have hereunto sub scribed my name in the presence of two witnesses.

HENRY l STAR-REIT,

Witnesses W. PERRY llAHN, Mania, REYNOLDS.

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