Pushbutton Switch Operator Assembly

This invention relates to a pushbutton device for controlling electrical apparatus.

"Push-pull" pushbutton switch operators are well-known in the art. It appears, however, that in the case of so-called, "emergency stop" buttons, certain regional practices have demanded rotational, or "twist-to-release", operation of the mushroon head operator to release the button after stop operation, in contrast to the conventional practice of providing a maintained contact, "push-pull" operation. That is, conventional pushbutton switch contacts are operated from their normal operating position by manually pushing a mushroom head operator inwardly in an axial direction. The contacts are maintained in such position by means of detent members acting against cam surfaces, or other means, and are released from that maintained position by an outwardly directed axial manual pull of the operator. In certain regions of the world, machine tool operating personnel use pushbuttons that are pushed inwardly to operate the contacts from a normal position, but are twisted or rotated to release the actuator and thereby return the contacts to the normal position.

In such devices, the usual biasing springs and cooperating mechanism required to provide torsional resistance have heretofore prevented installation of signal lamps which provide the operator with the usual visual indication of switch operation.

The present invention provides a pushbutton switch operator assembly, including a supporting base having a cavity which contains spring-biased detent means engageable with a cam profile defined on a side surface of an axially movable switching member. The switching member has a portion extending outwardly of the base for operational engagement of switch contacts on a cooperating contact module. The detent means and cooperating cam profile maintain the switching member in either a first or a second switch operating position. There is also provided a tubular actuator operated by the operator, and adapted for alternative axial and rotatable movement relative to an integrally formed tubular post extending inwardly of the supporting base. This actuator contains a groove for slidably receiving the switching member. Further, there is provided cam means between the base and the actuator to provide axial movement in a direction away from the base upon manual rotation of the actuator, and against the spring bias of a torsion spring, whereby the actuator may be manually moved axially either upon rotative operation under the action of the cam means, or alternatively, by a manual pulling action on the actuator to thereby alternatively cause the switch member to move axially in opposition to the action of the spring-biased detent member.

The particular embodiment described herein has adaptation for use in connection with contact modules such as those disclosed and claimed in U.S. Pat. No. 3,514,554 issued to Gerd C. Boysen on May 26, 1970, and assigned to the same assignee as the present invention.

The switch operator assembly of this invention comprises a series of cooperating, concentric, tubular members, the innermost supporting post projecting from a base member also arranged to receive a removable lamp and socket subassembly. A pushbutton operator is preferably of the "mushroom" type of a clear or colored translucent plastic material to provide illumination from the lamp. The terminals of the lamp socket are arranged for electrical connection with a transformer module, or for direct connection with circuit voltage, as desired.

FIG. 1 is a side elevational view of the switch operator assembly of this invention, and further disclosed in mounting position relative to a supporting panel;

FIG. 2 is a rear view of the assembly, taken in the direction of the arrow A in FIG. 1;

FIG. 3 is a longitudinal section of the assembly of FIG. 1, and with the several component parts in normal operating position with the pushbutton actuator extended relative to its supporting base;

FIG. 4 is a longitudinal sectional view, similar to FIG. 3, but with the actuator of the assembly being in depressed operating position relative to the supporting base;

FIG. 5 is a cross sectional view taken along lines 5--5 of FIG. 3;

FIG. 6 is an exploded elevational view, illustrating the various operating components in their unassembled relationship relative to one another; and

FIG. 7 is a perspective exploded view indicating the operational relationship between two functioning components.

Referring to FIGS. 1 and 2, there is shown a pushbutton switch operator assembly mounted on a panel 9, but with the switch contact module or modules or a transformer module, when required, omitted from the drawing. As stated previously, these modules are illustrated and fully described in the Boysen U.S. Pat. No. 3,514,554. The assembly comprises a threaded hollow bushing 10 attached to an insulating base member 11 by means of screws 12 of the type described and illustrated in the Boysen patent. The bushing is received in a circular opening in the panel 9 and is threaded to receive a mounting ring 13 seated against a legend plate 14. It is also usual to supply sealing and cushioning washers 15 between the base of the bushing 10 and the panel 9. A hollow, tubular actuator 16 is received in the bore of the bushing 10 and has attached to its outer end a threaded, mushroom head operator 17. The operator 17 is translucent and may be clear or colored. Extending from the open end of the base member 11 is a socket 18 for receiving a lamp, as will later be described. Also extending from the base member 11 through apertures 20 are two switching members 19a and 19b. As shown herein, the switching member 19b is shortened at its outer end to accommodate a transformer module (not shown) when lamps of reduced voltage are used. However, in all other aspects, the members 19a and 19b are substantially identical.

It will be observed from the remaining views that the switch operating assembly is comprised of concentrically arranged components each being tubular in nature or otherwise providing means for accommodating a lamp 21 and its socket 18. The lamp may be of the conventional bayonet type and the socket 18 includes terminals 22 engageable with connectors on a terminal module or transformer module, not herein shown. This arrangement, not only permits installation of the lamp and socket assembly, but further alternatively permits either manual axial push-pull, or rotational operation of the actuator 16, the latter resulting in a "twist-to-release" function for operating the pushbutton from the depressed position of FIG. 4 to the normal, extended position shown in FIG. 3, as will be hereinafter described.

In general, it will be noted that the base member 11 includes laterally extending, oppositely disposed cavities 34 and 25 which respectively receive cup-like detent members 26. Each of the detent members 26 is adapted to receive respective compression springs 27 bearing at one end against the inside surface of the cavity of each of the cup-like detent members 26 and at the opposite ends thereof against the inner wall of the respective cavities 24, 25. The free ends of the detent members 26 are arranged to receive and support rollers 28 suspended between oppositely extending pins 29 (see FIG. 5).

FIG. 3 is illustrative of the switch operator assembly with the operating parts disposed in the normally extended position, whereas FIG. 4 illustrates the same components positioned in the depressed button position relative to the supporting base member 11. It will be observed from FIG. 3 that the rollers 28 on the respective detent members 26 are at rest on the "fall" portion of the "dwell-rise-fall-dwell" cam profile of the oppositely disposed, axially slidable, switching members 19a and 19b. Each of the detent members 26 is illustrated in FIG. 3 in the spring-biased position with the rollers 28 resting in the "fall" position relative to the cam profile. The compression springs 27 are shown in their compressed position to effect this relationship. There is also a spring-bias exerted against the switching members 19a and 19b is an axial direction towards the normal operating position of FIG. 3, emanating from return springs of the contact block modules (not shown). This biasing action is further described in the aforementioned U.S. Pat. No.

3,514,554.

It will be observed that the switching members 19a and 19b are each provided with notches 30 in supporting and rotationally sliding engagement with inwardly disposed ledge portions 31 integrally formed in the tubular bore 32 of actuator 16. Thus, the switching members 19a and 19b will be moved in an axial direction concurrently with "push-pull" axial movement of the actuator 16. The opposite sides of each of the switching members 19a and 19b are slidably supported in oppositely disposed grooves 33 and 34 formed in the upstanding, hollow post 35 integrally formed with the base 11. This hollow post is further adapted to receive the lamp 21 and its socket 18. A cap 36 is sonically welded to the end of the post 35 and acts as a forward stop means upon engagement with the actuator 16.

It will be noted that manual depression of the mushroom head operator 17, which is in threading engagement with the actuator 16, causes the actuator 16, along with the switching elements 19a and 19b, to be moved to the depressed position shown in FIG. 4. The various components located interiorly of the assembly are sealed from the atmosphere by means of the compressible annular gasket 37 seated in the groove 38 and the lens gasket 39.

It will be observed from FIG. 4 that the rollers 28 of the detent members 26 will be caused to move from the "fall" portion of the cam profile on the switching elements 19a and 19b to the second "dwell" position shown in FIG. 4. The profile thus presents a rest position for the depression spring 27 in its distended position.

Thus, manual "push-pull" operation of the pushbutton assembly, which operation is particularly useful with "emergency stop" type of buttons, has been preserved by the present construction. This construction additionally accommodates the desirable illuminated signal means, provided by the lamp 21 and its socket 18.

As stated previously, the present invention further provides a "twist-to-release" function through the switch operator assembly. This function was heretofore difficult to obtain in the case of illuminated pushbuttons because of interference of spring-biasing components. In addition, this added function provides release means acceptable to certain markets foreign to the United States, where it is conventional to manually twist a stop button to return the same to normal operating position. This "twist-to-release" feature is attained by means of an integrally formed camming profile on the upstanding portions 40 and 41 disposed oppositely of one another on the base member 11. The portions 40 and 41 define ramp surfaces 42 and 43, respectively. The ramp surfaces 42 and 43 are arranged to slidably mate with corresponding ramp surfaces 44 and 45 located at the inner end portion of the actuator 16 (see FIGS. 6 and 7). A torsion spring 46 surrounds the post 35 of the base 11 and is received in the elongated notches 47 of switching members 19a and 19b. One end of the spring 46 is seated in an aperture 48 of the switching member 19a, and retained at its opposite upturned end seated in a re-entrant hole 49 of the actuator 16. It will thus be apparent that manual twisting or rotation of the mushroom head 17 and the actuator 16 threaded thereon will cause the ramp surfaces 44 and 45 on the actuator 16 to act against the respective mating ramp surfaces 42 and 43 to impart an axial movement to the actuator 16 in a direction away from the base 11, and thus concurrently withdraw switching elements 19a and 19b to the position shown at FIG. 3 against the spring bias of the springs 27 and the detents 26.