US1787210A - Push-button electric switch and cover plate therefor - Google Patents

Description

1,787,210 PUSH BUTTON ELECTRIC SWITCH AND COVER PLATE THEREFOE Dec. 30, 1.930. G. w. OKEEFFE Filed June 27, 1928 W WW I.

Patented Dec. 30, 1930 UNETED STATES PATENT OFFICE GEORGE W. OKEEFFE, OF MILTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELEC- TRICAL MANUFACTURING CORPORATION, OF

CORPORATION OF MASSACHUSETTS PUSH-BUTTON ELECTRIC SWITCH AND COVER PLATE THEREFOR Application fiiea'iune 2?,

10 cated at a distance from the point of control.

A dangerous situation arises when the motors or the apparatus connected thereto or associated therewith are being repaired, and in spite of the customary precautions taken,

15 it has frequently happened that the switch has been carelessly or accidentally operated and injury has resulted.

It is an object of this invention to provide an accessory device for a push button control switch whereby to render the switch temporarily inoperative to control the circuit.

The control switch is usually adapted to control the operation of an electromagnetic switch and has a start button to close the a. electro-magnetic switch and a stop button to open the electro-magnetic switch. Said switch includes a winding or coil which is energized initially by the momentary depressing of the start buttonto effect the closing of the switch which, when closed, completes a holding circuit through the coil to keep the coil energized and the switch closed. The holding circuit is opened by momentarily depressing the stop button, whereby to 5 open the switch. It is therefore possible, by manual operation of the electro-magnetic switch, to close the motor circuit even though the push button control switch be enclosed in a locked cabinet. Under these circumstances the motor circuit will remain energized until the stop button is depressed, due to the holding coil. 8

It is therefore a further object of this invention to provide suitable means for preventing access to the control buttons of the switch which will also disable the holding coil circuit of the electro-magnetic line switch.

Another object is the provision of a lockout plate which will cover both push but- 0 tons of the control switch, so that they can- 1928. Serial No. 288,726.

SOUTH BOSTON, MASSACHUSETTS, A

not be operated readily, and also will hold I casing partly broken away.

Fig. 3 is a front elevation of the lockout plate.

Fig. 4 is a side elevation of the lockout plate of Fig. 3.

Fig. 5 is a perspective view of the plateholding screw.

Fig. 6 is a diagram of the connections of a remote control push button switch with which the invention is concerned and an electro-magnetic switch controlled thereby.

As herein shown the invention is illustrated in connectionwith a remote control switch A (Fig. 6) which is adapted to control the operation of a motor 13 by means of an electro-magnetic'line cont-actor or switch C. Said control switch A comprises specifically a pair of selectively operable movable switch members 10 and 12 having a common pivotal support at 13 on a terminal member 14 which is secured to an insulating base 15'.

Said movable switch members are provided with radial arms 16 having inwardly-directed, overlapping arcuate extensions 18, and a compression spring 20 is disposed loosely on saidextensions 18 with its cpposite ends in engagement with said arms 16, whereby to bias them constantly into a normal position against abutments 22 on said terminal member 14. Means are provided to move said switch members 10 and .12 away from said abutments 22 against the bias of the spring 20. Said means comprise the push buttons 24 and 26 provided with posts 28, which are pivotally connected at 30 and 32 to said arms 10 and 12 respectively. Said buttons are guided for straight line motion by aframe 34:, secured to said insulating base 15, which frame has suitable apertures 35 therein to receive said buttons.

Fixed contact members, comprising the U-shaped resilient clips 36 and 38, are sup butcooperating movable switch member 12 is in engagement therewith when in its normal position against its abutment 22. The insulating base 15 and the switch assembly mounted therein is secured removably within a casing 37 by means of suitable bolts ere tended through the frame 34 into said casit cover provides the front closure for saic casing 37 and comprises a substantially rectangular flat plate 40 which is acapted to overlie sai'd'frame 34, an integral outwardly flared peripheral flange 42, and a substantially rectangular frame 43 which lies flush with the front edge of the casing 37. Said rectangular frame 43 is further provided with an angularly related peripheral flange 44 which fits closely about the side walls of the casing 3? to provide a weather-tight joint thereabout, and also to prevent relative movement of said cover and the casing 37. Said cover plate 40 is provided with apertures to receive the buttons 24 and 26 which are aligned with the apertures '35 in frame 34, and a bolt 46 is extended loosely through the plate and is screw threaded into the frame 34, whereby to secure the cover removably to the frame '34 and thus to the casing 37. The outer end of said buttons 24 and 26 in their normal position are adapted to lie'somewhat beneath the frame 43 whereby to be protected from accidental blows. The details of construction of the bush-button switch are described more particularly and are claimed in my copending application, Serial No. 228,725, iil'ed June 27, 1928.

As shown in Fig. 6, the movable switch member 10 and the fixed contact 36 comprise an energizing switchtor the electromagnetic switch C and, upon depressin the start button 24, complete a circuit including the line conductor 48, switch arm 10, contact 36, winding and line conductor 54, thus to close the electro-magnetic switch 0 and, through the latter, the circuit through motor B. The closing of the electro-magnetic switch also completes a holding circuit for itself. Said holding circuit includes the line conductor 48 the second switch arm 1-2 of the push button switch, contact 38, auxiliary contacts 52, winding 50, and line conductor 54. Upon depression of the stop button 26, the holding circuit is opened and the coil 50 is deenergized, thus opening the 'ele'ct ro-'magnetic switch. This is a more or less common arrangement for the remote control of electric motors.

When it becomes necessary to make repairs or for any reason to work on the motor B, or the machine connected thereto, it is essential that the control switch A be rendered inoperative to energize the electromagnetic switch C. To this end, a substantially flat rectangular lock-out plate 56 is provided, see Figs. 3 and 4, which plate is adapted to lie within the depression of the cover of the control switch and flush with said frame 43 and with its periphery bearing against the outwardly flared flange 42 thereof. As shown in Fig.2 said lock-plate 56 when in position on the switch cover completely covers said plate 40 and the flange 42 thereof and is spaced slightly from .the extended end of button 24. Said lockplate is further provided with a struck-out portion 58 having a flat extended face '59 whichconforins with theend of said button 26,

and whichenga-ges and holds said stopbutton 26 depressed when said lock-plate is in the position illustrated in Fig. '2, whereby the switch arm 12 of the stop switch is held out of contact withits cooperating, contact 38, and the holding coil circuit includingwinding 50 thus is maintained open.

The bolt46 which secures the cover to the casing 37 is located at one side of the vertical center line thereof which includes the push buttons and is provided with a some- "what enlarged head '60 which is internally screw threaded to receive a screw 62 which extends through a hole 63 in the lock p'late 56 to hold thecover plate on the switch casing. The screw 62 is adapt-ed normally to remain. in the enlarged head and thus to be available whenever it is desired to attach the lock-plate. By the provision of an eccentrically located attaching bolt tor the l'oclnout plate, itis impossible. to secure the plate to the casing .in a position to depress the startbutton.

With the lock-out plate in position, as shown in Figs. 1 and '2, the start button is wholly inaccessible, and the stop button 26 is maintained in a depressed position by the struck-out portion 58 so that the contact 38 is free from engagement with the switch arm 12 and under no circumstance can the holding coil circuit be completed through the winding 50-of the line contactor C.

I claim 2 1. In an electric switch, the combination of an enclosing casing, a pair of switch operating push buttons extended through and beyond the outer wall of said casing, means separate from said casing having means to ai'fix it temporarily to said casing and when afliX-ed to said casing arranged to cooperate herewith to enclose the extended ends of both push buttons and also to maintain one only of said push buttons in a depressed position.

2. In an electric switch, the combination of an enclosing casing having two pairs of stationary and movable switch members therein, a push button operatively associated with each of the movable switch members within said casing and movably extended through and outwardly beyond the wall of said casing, means to bias said movable switch members normally. into a position whereby said push buttons are extended into the aforesaid position beyond said casing wall, and detachable means cooperating with said casing to enclose the extended end of both buttons and also to depress one of said buttons against said biasing means.

3. A push button electric switch having a casing, two selectively operable movable switch members within the casing, a push button for each of said movable switch members slidably received in said casing, means to bias said push buttons normally into position to project from. said casing, and a lockout plate for said switch arranged to cooperate with said casing to enclose the proj ecting ends of said push buttons and having means to engage and maintain one of said buttons depressed against said biasing means.

4. A push button electric switch having a casing, two sets of cooperating stationary and movable switch members disposed within said casing, apair of push buttons projecting from said casing for operating said movable switch members selectively, means normally biasing one of Said sets of switch membersout of engagement and the other of said sets into engagement, and a lock out member having a detachable connection with said casing arranged to enclose the projecting ends of said push buttons, said lock-out member also provided with means to engage and depress the push button of said second set of switch members whereby to maintain said switch members out of engagement.

5. A push button electric switch having an enclosing casing, cooperating stationary and movable switch members within said casing,

said movable switch member being biased into engagement with its cooperating stationary switch member, a push button projecting from said casing for operating said movable switch member against its bias into a position free from engagement with said stationary switch member, a lock-out plate having a detachable connection with said casing, said plate having a projection there of in position to engage and maintain said push button in position to hold said stationary and movable switch members out of engagement against said biasing means.

6. A push button switch having an enclosing casing, a pair of cooperating stationary and movable contact members within said button projecting from said a lock-out plate means securing said casing, said movable contact member being biased out of engagement with its cooperating stationary contact member, a push button projecting from said casing for operating said movable contact member against its bias to effect the engagement thereof with its cooperating stationary contact member, a second pair of-stationary and movable contact members within said casing normally biased into engagement, a push button projecting from said casing for operating said second movable contact member against its bias to separate it from engagement with its cooperating stationary contact member, and a lockout plate cooperating with said casing to enclose both of said buttons, said lock-out plate also having a projection arranged to engage and depress said second push button and maintain said second contact members out of engagement.

7. A push button electric switch having an enclosing casing, a pair of cooperating stationary and movable contact members within said casing, said movable contact member being biased out of engagement with its cooperating stationary contact member, a push casing for operating said movable contact member against its bias to effect the engagement thereof with its cooperating stationary contact member, a second pair of stationary and movable contactmembers within said casing normally biased into engagement, a push button projecting from said casing'for operating said second movable contact member. against its bias to separate it from engagement with its cooperating stationary contact member, cooperating with said casing to enclose said push buttons and having a projection arranged toengage and maintain said second push button in a depressed position, said lock-out plate having a detachable connection with said switch casing located eccentrically thereof, whereby to prevent the attachment of said plate in an inverted position. i

8. An electric switch having a casing and a pair of superposed switch operating push buttons projectingtherefrom, means to bias said push buttons into the aforesaid position, and a guard member adapted to be affixed removably to said casing arranged to overlie the projecting ends of said push buttons, said guard member also having a pro jection thereon arranged when said member is afiiXed to said casing to engage and hold one of said push buttons depressed, and guard member to said casing located eccentrically thereof so that said guard member cannot be improperly affixed to the casing.

9. An electric switch including an enclosing casing having a substantially rectangular recess in an outer face thereof, a pair of superposed push buttons projecting from said casing :intosai-d recess, .a plate disposed within and conforming to the said recess and spaced from the projecting ends of said buttons, said'plate havin a struck-out portion arran ed to-engage and depress one of said buttons, and an attaching bolt passed loosely through said plate and screw threaded into said casing, said attaching bolt being disposed at one side of a line through said superposed buttons. 7

10. A lock-out device for an electric switch hold it depressed, said plate having an attaching hole therethrough which is located at one sideof the longitudinal axis of the plate.

In testimony whereof, I have signed my name to this specification.

GEORGE W. OKEEFFE.

of the type having an enclosing casing and two switch I operating buttons projecting from a wall thereof, comprising a cover for .1 said casing wall overlying and spaced from said cover attached to said casing, a rectangular safety plate occupying said depression above said push buttons and having a projection which engages one of said push buttons and holdsit depressed, and a screw passed through said safetyplate at one side of the line of said push buttons and having a screw threaded engagement with said cover holding screw.

12. A push button electric switch having an enclosing casing, push buttons projecting therefrom, and a cover'plate located on said casing over said push buttons above and out of engagement with one of said buttons and having a projection which is located above and bears against another of said buttons whereby to maintain it depressed, and means to secure said plate only in the aforesaid relation on said casing. 7 13. A push button electric switch having an enclosing casing, push buttons projecting therefrom, and a cover plate located .on said casing over said push buttons above and out of engagement with one of said buttons and having a projection which is located above and bears against another of said buttons whereby to maintain it depressed, and attaching means passed through said plate at one side of a line passed through said push buttons and connected with said casing, whereby to secure said plate only in the afore said relation to said casing.

14. A safety plate for a push button switch having a pair of extended push buttons, which plate is rigid, flat and rectangular and has an integral struck-out boss that is adapted. to overlie and engage one push button and

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