US2673259A - Locking device for push-button stations - Google Patents

Description

March 23, 1954 N. A.IAPPLETON ET AL LOCKING DEVICE FOR PUSH-BUTTON STATIONS Filed Nov. 14', 1951 Inventors horton aa npleton Richard J Krause Patented Mar. 23, 1954 LOCKING DEVICE FOR PUSH-BUTTON STATIONS Norton A. Appleton and Richard J. Krause, Chicago, 111., assignors to Appleton Electric Company, Chicago, 111., a corporation of Illinois Application November 14, 1951, Serial No. 256,258

4 Claims.

'1 The present invention relates in general to the field of locks for electric switches. More specifically, the invention is concerned with a novel locking device for push-button stations such as locking device of exceptionally simple and economical construction and which requires no costly modification in the construction of the switch with which it may be used but simply takes advantage of switch structure already present.

A further object is to provide a locking device for push-button stations and which possesses a high degree of flexibility in adaptation and is usable with a wide variety of ordinary padlocks.

Other objects and advantages of the invention will become apparent from the following description, taken together with the accompanying drawing, wherein:

Figure 1 is a perspective view of an illustrative push-button station equipped with a novel locking device which exemplifies the present invention.

Fig. 2 is a front elevation of the push-button station and locking device shown in Fig. l, but

with the latter in its locked position.

Fig. 3 is a fragmentary horizontal sectional view of the illustrative device taken in the plane of the line 33 in Fig. 2.

Fig. 4 is a fragmentary vertical sectional view through the illustrative device, taken in the plane 'of the line 44 in Fig. 2.

Fig. 5 is an enlarged perspective View showing details of the fixed bracket which constitutes a major element of the device.

. Figs. 6 and '7 are elevational views of the movable element of the novel locking device, illustrating certain variants in its lateral edge contour.

While the invention is susceptible of various modifications and alternative constructions, certain preferred embodiments have been shown in the drawings and will be described below in considerable detail. It should be understood, however, that there is no intention to limit the invention to thespecific forms of locking devices disclosed herein, but'on the contrary, the intention is to cover allmodifications, alternative constructions and equivalents falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more specifically to the drawings, the invention is there exemplified in a novel look ing device it installed on an illustrative pushbutton switch II. In this instance, the switch l I happens to be a start-stop switch of the explosion proof type and may, for example, be used to control a remotely located electric motor (not shown). As illustrated in Fig. 1, the switch ll may be mounted on an appropriate box l2 and has a plate it which serves as the box cover. A casing l5 integral with the plate l4 houses the current carrying elements of the switch. The casing It has a front face It from which a pair of resiliently loaded, depressible push-buttons I8, 19 project. The upper button, designated by the reference numeral l8, happens to be the start button while the lower button, designated by the numeral It, happens to be the stop button. As indicated in Fig. 4, each push-button is fastened to an individual plunger 20, the latter being surrounded by a coiled compression spring 2| interposed between the button and the front face E6 of the switch casing. Each of the push-buttons It, It is partially surrounded by a corresponding one of a pair of protective abutments 22. In this instance, the abutments 22 are of substantially semi-circular or horseshoe shape and are integral with the switch casing [5. The abutments 22 are disposed with their open ends facing toward the center of the face 16, presenting convex surfaces toward the extremities of the face it so as to ward off accidental blows which might otherwise tend to damage the push-buttons l8, IE or bend their plungers 2!).

Taking full advantage of the switch structure thus far described, the novel locking device [0 comprises a fixed bracket 24 (Figs. 3, 4 and 5) susceptible of rigid attachment to the switch face it in the space between the push buttons l8, l9 and their respective protective abutments 22. As shown clearly in Figs. 3 and 5, the mounting bracket 26 is substantially U-shaped and comprises a laterally offset intermediate portion 25 terminating in a pair of spaced apart, substantially parallel arms 25, 23. The arm 26 terminates an outturned portion 23 having an oblong lociring eye 38 therein. The arm 2%,on the other hand, terminates in an outturned portion which may be bifurcated so as to define a pair of closely spaced supporting fingers 3| therein.

The offset portion 25 of the mounting bracket 25 has holes 32 for receiving mounting screws 36 which may threadedly engage corresponding tapped holes in the switch face I5.

Slidably abutting th outturned portions 29, 3| of the bracket is a locking slide 55 (Figs. 3, 6 and 7). The latter has a locking eye comparable in size and shape to the eye 35 of the bracket 25. The end portion 38 of the slide 35 remote from the eye 36 is bent toward the switch face I6 and lies substantially parallel with the bracket arm 28. The slide 35 has an instruck tongue 39 adjacent the eye 36 and bent into substantially parallel relation with the arm 25 of the fixed bracket. The members 38, 39 are spanned by a longitudinal sliding pin (Figs. 3 and 4) which passes through alined openings 4| in the bracket arms 26, 28 so as to hold the slide 35 against the bracket 25.

The slide 35 is normally biased so that its eye 35 will register with the eye 35 of the mounting bracket, such being accomplished by the use of a coil spring 52 interposed between the arm 28 and the plunger end 35 and disposed in surrounding relation with the pin Gil. This position of the slide 35 will be designated as its normal position. The slide 35 may also be shifted manually to the right, as shown in the drawing, in opposition to the thrust of the biasing spring 42 until the eye 36 extends beyond the end of the eye member 29 of the bracket. This position of the slide will be designated as its extended position.

Provision is made in the device to for locking either or both of the push-buttons l3, iii in a depressed or a non-depressed position, depending upon the requirements of the particular push-button station at which the device it] is installed. This is accomplished by contouring each of the lateral edges of the slide 35 so that it will either intercept or remain clear of its associated push-button when the slide is in its normal, as well as in its extended, position. Such contouring may vary for different applications, being tailored to meet the needs or" a given installation. As shown in Fig. 2, the slide 35 is formed with a pair of alined clearance notches M, 45, permitting free movement of the respective push-buttons l8, l9 when the slide 35 occupies its normal position. When, however, the slide 35 is urged manually into its extended position as illustrated in Fig. 1, the non-relieved lateral edges thereof are adapted to intercept the push-buttons l8, l3 and to retain either or both of them a depressed or a non-depressed position. Ihe push-buttons may thereupon be locked in a given condition by inserting the l yoke 16 of a padlock through that portion of the eye 35 of the slide extending beyond the end of the bracket eye member 29.

tudinally into an intercepting position. On the other hand, coaction between the push-buttons and the slide 35 when the push-buttons are in non-depressed position, as illustrated by the push-button IS in Fig. 4, is easily accomplished by contact between the bottom face of each pushbutton and the slide.

For the purpose of enabling an individual to install the device It) so that the slide 35 and bracket 25 will be in proper registry with the push-buttons l8, [9, the eye ends of the memhere 2 1, 35 are laterally enlarged to define locating shoulders 55, El (Figs. 2 and 5). The shoulders 55, 5! are proportioned and located so that they will bear against the protective abutments 22 on the switch face 16 and precisely position the mounting bracket 25 and the slide 35 relative to the push-buttons.

Preferably, when installing the device H), the bracket 24 alone is installed first by means of the mounting screws 34. The slide 35 is then placed upon the bracket 25 and the pin and spring 45, 42 are then installed in place, such parts being retained in assembled condition as by peening the end of the pin re. With the slide 35 thus mounted in place, it will be appreciated that the heads of the mounting screws 34 are effectively masked, making it extremely diflicult for a careless operator to remove the screws 34 and detach the locking device In.

In Figs. 6 and '7, certain variants in edge contour of the slide member are illustrated. Thus Fig. 6, the upper edge or slide 35A has a relatively long clearance notch 52 which leaves its associated push-button free to be operated while the slide 35A is in either its extended or in its normal position. The bottom edge of the slide 35A has a smaller clearance notch 54, leaving its associated push-button free to be operated only when the slide 55A is in its normal position. The unrelieved lateral edge portion of the slide adjacent the notch 55 is consequently adapted to engage the push-button and lock it either in its depressed or non-depressed position when the slide 35A is in extended position. The slide 353, illustrated in Fig. 7, is substantially identical with the slide 35A except for the fact that its longer clearance notch 55 is located on its lower edge while its shorter clearance notch 55 is located on its upper edge. This of course produces a converse locking effect from that produced by the slide 35A.

Upon reflection, it will be appreciated that the locking device described above adequately fulfills the objects set forth earlier herein. Its two major parts may easily and cheaply be constructed in the form of sheet metal stampings which may be assembled by fastening elements of utmost simplicity. The device ill in no way complicates or increases the cost of the push-button switch with which it may be used but simply takes advantage of existing switch structure in its mounting arrangement and operation. As indicated earlier herein, the device Ill may, with equal facility, be assembled with the switch at the factory or may be provided as an attachment to be installed by the user at an existing push-button station.

We claim as our invention:

1. In a switch structure having a pair of depressible push-buttons, the combination of an oiTset bracket comprising an intermediate portion susceptible of rigid attachment to said switch between said push-buttons, said bracket also hav ing spaced apart arms one of which terminates in a locking eye, a locking slide having lateral edges contoured for selective interception of respective ones of the push-buttons, said slide also having a locking eye normally disposed in registry with the locking eye of said bracket, and spring loaded means interposed between said bracket and said slide for maintaining the latter with its locking eye normally in registry with the locking eye of said bracket.

2. In a switch structure having a pair of depressible push-buttons and also having a pair of protective abutments disposed in spaced apart opposed relation adjacent respective ones of said push-buttons, the combination comprising a bracket having an oifset intermediate portion susceptible of rigid attachment to said switch between said push-buttons and said abutments, said bracket also having spaced apart arms, a locatin shoulder on one of said arms adapted for abutting engagement with one of said protective abutments, said one arm also terminating in an outturned locking eye, a locking slide having a normal position and an extended position, said slide also having lateral edges selectively contoured for interception of respective ones of the push-buttons with said slide in either position, said slide having a locking eye, a locating shoulder on said slide adapted for abutting engagement with one of said protective abutments, a pin fixed to said slide and to said bracket but having sliding engagement with the latter, and a loading spring interposed between said bracket and said slide for maintaining the latter with its locking eye normally in registry with the locking eye of said bracket, said loading spring being disposed in surrounding relation with said pin.

3. An external locking device for push-button stations comprising, in combination, an ofiset bracket having a medial portion adapted for fixed attachment to a pair of depressible push-buttons, said bracket also having spaced apart arms one of which terminates in a locking eye, a locking slide having lateral edges selectively contoured for interception of respective ones of the pushbuttons in a depressed as well as in a nondepressed position, said slide also having a looking eye normally disposed in registry with the 6 locking eye of said bracket, and spring loaded means interposed between said bracket and said slide for maintaining the latter with its locking eye normally in registry with the locking eye of said bracket.

4. An external locking device for a switch structure having a pair of depressible push-buttons and a pair of protective abutments disposed in spaced apart opposed relation adjacent respective ones of said push-buttons, said locking device comprising, in combination, a bracket having an ofiset intermediate portion susceptible of rigid attachment to said switch between said pushbuttons and said abutments, said bracket also having spaced apart arms, a locating shoulder on one of said arms adapted for abutting engagement with one of said protective abutments, said one arm also terminating in an outturned locking eye, a locking slide having a normal position and an extended position, said slide also having lateral edges selectively contoured for interception of respective ones of the push-buttons with said slide in either position, said slide having a looking eye, a locating shoulder on said slide adapted for abutting engagement with one of said protective abutments, a pin fixed to said slide and to said bracket but having sliding engagement with the latter, and a loading spring interposed between said bracket and said slide for maintaining the latter with its locking eye normally in registry with the locking eye of said bracket.

NORTON A. APPLETON. RICHARD J. KRAUSE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,205,798 Scholder Nov. 21, 1916 2,579,168 Ballou Dec. 18, 1951

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