US2119220A - Control switch for electrically operated devices - Google Patents

Description

May 31; 193s.

L. A*.scRucscss CONTROL SWITCH FDR ELECTRICALVLY OPERATED DEVICES original ymired 'June 22. 1935 mmm@ /N veA/'rom Y L'o ya 565214665,

lPatented May 3l, 1938l OPERATEDy DEVICES Leya Scruggs, University city, Mo.

Original application .lune 22, 1935, Serial No. 27,893. :Patent 4No. 2,0825264, dated June l,

Divided and this application February 8,

' 1936, Serial No. 62,875

1 Claim.y (Cl. 20D-157i .This invention relatesto a novel control switch for electrically-operated devices, my present ap'- plication being a division of my pending applica'- tion for patentl Serial No. 27,893, iiied June 22,

1935, now Patent No. 2,082,264, patented June 1,

The main object of my invention is to provide an inexpensive control Aswitch of rugged construction and simple design, whose actuating'member is constructed-in the form of a cap piece recipro- -catingly mounted on oneend of the handle, housing or equivalent part of the electrically-operated device with which the switch is used; thereby enabling said device to 'be started and .stopped or if thehandle should be subjected to a sharp' blow or shock, the movable member of the switch will move automatically in a direction to cut off the supply-of electrical energy to said device,

as being used for controlling the operationv of an electric motor of a device that `is intended to be held in the hand ofthe person who is manipulating a tool or instrument attached to the armature shaft ofthe motor, but I wish it to be understood that said switch is capable of use with various other types and kindsof electrically-oper ated devices.

Figure 1 of the drawing is a longitudinal sectional view of a fractional horsepower electric motor equipped with'a control switch constructed in accordance with my invention.

' Figure 2 is a cross-sectional view, taken on the line 2--2 of Figure `1, looking in the direction indicated by the arrows;

Figure 3 is a fragmentary longitudinal sectional view,' taken on the-line 3 3 oi' Figure 1; and

Figure 4 is a fragmentary longitudinal section view, taken on the line 4-4 of Figure 2 In the accompanying 4drawing, which illustrates the preferred form of my invention, A designates the laminated ileld core of a-fractional horse.- power electric motor, B' designates the armaturev 50 core, C designates the commutator; D-designates the amature shaft, andK designates a chuck that.

.shatt'n The housing of the` motor. is made o f 55 such shape and dimensions that it virtually consimply by pushing said cap piece inwardly or I have herein illustrated my improved switch? said member to stop the motor. vided for restricting the outward movement of the stitutes a handle which is adapted to be grasped by one hand ofthe user, and in the motor herein illustrated, the housing is made up of two end 'members F and G of insulating material, and a tubular shell H whose end portions overlap said end members. The'brushes I5 thatco-act with 'the commutator C vare carried by tubular-shaped `brush holders I6 and Il-.mounted in the rearhousing member G in parallel relation to the armature shaft and provided at their outer ends with screws I6, and I1i that serve as abutments for the springs' I5a which force the brushesli against the cominutator.I Said brush holders I6 :and I1 are attached to brass contact plates I8 and I9, respectively, that are mounted' in the rear housing member Gand connected in any preferredorsuitable way with the iield coils.

The electrical energy used to'actuate the motor is controlled by a switch embodying my invention, and constructed in such a manner that it is practically built vinto the motor, so as to form an integral part of same, the actuating member of said switch being so arranged that it forms a cover or cap piece :for the rear end member G of the motor housing. Preferably, the actuating member of said switch is formedby a cap piece J, made of insulatingmaterial, and provided with a flange 22 which surrounds a' reduced cylindrical portiono'n the' rear end of the 'housing member G, as shown in Figures, 1 and 3, said reduced cylindrical portion being of such length that the tudinally in the opposite direction.' into its oit positionf,sho wn in Flgure 1. Obviously, the parts of the switch might be arrangedso as to cause inward movement of the me'mberJ to set the motor` in operation, and outward movement of Means is procap member J, and in the form of my invention herein illustrated, said restricting means. is formed .by a plur'ality of screws 2l projecting in'- wardly through the cap member J and screwed into the. rear housing member G,.the shanks of said screws being of such length that when th'e cap member J is moved outwardly, or to the right looking at Figure 1, the inner end walls of` counterbores 2l in the cap member J will strike einst the heads of the screws 23,' and thus causev said cap member to come to rest in such a position that electrical connection is established between the contact plates I8 and I9 and the wires 25 and 25EL of a duplex cord 26 that is attached to the cap member J. The screws 23 are accessible through the counterbores 24 in the cap member J, thereby enabling said cap member to be easily disconnected from the rear housing member G in the event it becomes necessary or desirable to inspect, or remove the brushes I5, the screws I6a and I1a in the brush holders being normally protected and concealed by the capl member J. The particular means employed to establish and interrupt the electrical connection between the contact plates I8 and I9 and the wiresI of the duplex cord 26, is not important, so far as my broad idea is concerned, but I prefer to provide the actuating member J with a pair of prongs 21 and 28, attached to the wires of the duplex cord 26, and constructed, proportioned or arranged so that they co-operate with the plates I8 and I9 to complete or break the circuit, depending upon the position of the cap member J. In the form of my invention herein illustrated the inner ends of the prongs 21 and 28 project through holes in the contact plates I8 and I9, as shown in Figure 4. One of said prongs is of such cross sectional shape and dimensions that when the cap member J is pushed inwardly into the position shown in Figure 1, the outer surface of said prong will be spaced away from the edge oi the hole inthe contact plate with which it co-operates, thereby opening the circuit, and when the cap member J is pulled outwardly. as shown in Figure 4, both of the prongs 21 and 28 will bear against the edges of the holes in the -contact plates I8 and I9, thereby establishing to connect the wires 25 and 25a to the prongs 21 and 28 are housed within the cap member J and are effectively insulated from metallic portions on the outer side of the rear housing member G. To this end I form the cap member J from two pieces of insulating material, detachably con-- nected together by screws 29, as shown in Figure 4, that are accessible after the cap member J has been dismounted from the rear housing member G, and I provide the prongs 21 and 28 with binding screws 30 that are positioned in notches or cut-out portions formed in the outer piece or part of the cap member J, as shown clearly in Figure 4. A control switch of the construction above described contributes greatly to the ease of handling and operating the electrical device with which the switch is used, due to the fact that the actuating member of said switch is formed by a cap piece reciprocatingly mounted on the handle, housing or equivalent part of the electrically-operated device, and hence, can be easily manipulated to start or stop said device simply by moving the cap piece outwardly or pushing it inwardly. Another desirable feature of such a switch is that if the electrically-operated device should be accidentally dropped, or if the rear end portion of the handle of said device should receive a sharp blow or shock, the control member J of the switch will automatically move inwardly, and thus cut off the supply of electrical energy to the device. In addition to the desirable features or characteristics above pointed out, my improved control switch is inexpensive to construct, and it is of sumciently rugged design to successfully stand up under the rough usage or treatment which it is liable to be subjected to when in service.

g Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A control switch for an electrically operated device, comprising a stationary part made of insulating material, concealed contact plates car ried by said part. a reduced cylindrical portion on said stationary part, a shiftable cap member made of insulating material reciprocatingly mounted on and surrounding the reduced cylindrical portion on said part, combined retaining devices and limiting stops for said cap member threaded into the end of said stationary part and provided with enlarged heads positioned in counter-bored holes formed in the end face of said cap member, prongs on said cap member positioned in holes in said stationary part and adapted to be moved into and out of operative relationship with said contact plates by reciprocating said cap member on the reduced cylindrical portion on said stationary part, a duplex cord whose wires are attached to said prongs on the interior of said cap member, said cap member being 'composed of two pieces, and a means for detachably connecting together the two pieces of said cap member consisting of screws that are normally concealed from view and which are accessible only after said cap member has been completely' disassembled from said stationary part. o

LOYD SCRUGGS.

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