US3404244A - Compact electrical switch assembly with improved actuator means - Google Patents

Description

c 1, 1963 J. w. AMIS, JR., ETAL 3,404,244

COMPACT ELECTRICAL SWITCH ASSEMBLY WITH IMPROVED ACTUATOR MEANS Filed Jan. 30, 1967 2 M 23 44 49-/2/ t3? a pm 2 i ,1 47 w l I JAMES M 14/7/5 g I BY 641?) E. ANDERSON 44 7 M40, WEM 1926.

,4 TTOR/YE Y8 United States Patent 3,404,244 COMPACT ELECTRICAL SWITCH ASSEMBLY WITH IMPROVED ACTUATOR MEANS James W. Amis, Jr., Bellevue, and Gary E. Anderson,

Seattle, Wash, assignorsto Korry Manufacturing Company, Seattle, Wash., a company of Washington Filed Jan. 30, 1967, Ser. No. 612,431 9 Claims. (Cl. 200-) ABSTRACT OF THE DISCLOSURE A cluster type electrical switch assembly wherein a plurality of button-actuated microswitches, referred-to in the art as subminiature basic switches, are compactly positioned within a common housing around an axially located plunger-type actuator, which includes a flanged actuator member mounted for relative movement along a plunger between mutually aligned actuator and return springs and operable to engage and operate the microswitch buttons. The actuator member and springs are arranged within the assembly so that the actuator spring, by which actuation force is transmitted, absorbs overtravel of the plunger after the microswitch buttons are depressed, and-the return and actuator springs restore the actuator member and the plunger to their respective initial positions after pressure is released from the plunger. The actuator also incorporates means for mounting the assembly on a panel or other component.

Background and summary of the invention This invention relates to a compact electrical switch device including a plurality of microswitches operable simultaneously by means of a common actuator. More particularly, it relates to a switch assembly including subminiature basic switches arranged compactly within a common housing around an axially located plunger-type actuator having means for absorbing overtravel of the plunger after the basic switches are operated, and other features described herein. While the invention is described in terms of a preferred form thereof, it will be recognized by those skilled in the art that various changes and modifications may be made therein without departing from the principal features involved.

There is in the art a continuing effort to make electrical devices, components, and subassemblies smaller in order to achieve compactness in the instruments and systerms in which they are used, consistent with the practical requirements of manufacture, repair, replacement, and reliability. At the same time there is a continuing effort to simplify electrical systems and devices to reduce the required number of manual operations. This frequently places on switches and the like unusual demands for simultaneous multiple functions, such as making a large number of electrical connections simultaneously by single actuation. Such efforts toward operational simplicity have frequently resulted in undue physical complexity in multiple-function switching devices, and compactness has been difficult to achieve without sacrificing reliability.

' It is the chief object of this invention to provide an electrical switching assembly of improved compactness, simplicity and reliability.

A related object is to provide a plunger-actuated switching device requiring a minimum of adjustment on account of wear during the life of the device.

Another object is to provide a plunger-actuated switching device utilizing available subminiature basic electrical switch components arranged so as to fit within a smaller space than has heretofore been achieved with such components.

Still another object hereof is to provide in such a switching device improved cooperative relationships among the parts, especially between the plunger-type actuator and the parts associated with achieving the compactness of arrangement of the subminiature basic switches.

Another object hereof is to provide in such a compact switching device, an improved plunger-type actuator providing for transmittal of actuating force to the buttons of the basic switches through a spring which also absorbs overtravel of the plunger, cooperative with means other than the basic switches themselves for returning the plunger to its initial position, all reducing wear on the basic switches, and at the same time including in the actuator, means for attaching the device to a mounting panel or other component.

Accordingly, the invention supplies an electrical switching device in which are included a plurality of buttonactuated basic microswitch components arranged about a common axis so as to form a central cavtiy and having their actuator buttons directed longitudinally of the axis for operation by a common actuatorv The actuator is contained in the central cavity and includes a plunger ex tending along the axis, a plunger return spring, an actuator member mounted for relative movement along the plunger and having means thereon operable to engage and operate the actuator buttons of the basic switches, and a stop and an actuator spring mounted on the plunger holding the actuator member therebetween, whereby the actuator spring is operable to transmit actuation force from the plunger to the actuator member to operate the respective basic switch buttons, the actuator and return springs both absorbing overtravel force after the basic switch buttons are depressed, and the springs serving respectively to return the actuator member and the plunger to their initial positions.

Preferably, the actuator also includes means for attaching the switching device to a panel or other component, such as an illuminated indicator. For this purpose first and second flanged and mutually threaded fastening elements are provided, each being hollow to receive an actuator rod operable to actuate the plunger. The first fastening element is positioned within the housing containing the switching device and includes a hollow shank portion adapted to receive one end of the plunger and one or more longitudinal slots extending along the shank portion. The plunger includes one or more lateral projections slidably received in the longitudinal slots and permitting relative longitudinal motion of the plunger and fastening elements in response to force applied by the,

actuator rod. The plunger includes means on its opposite end operable to receive a turning tool, such as a screwdriver, whereby the plunger can be rotated, whereupon the lateral projections received in the slots in turn rotate the first fastening element to thread it onto the second fastening element.

The invention further resides in certain advantageous details of construction and cooperative relationships of the parts thereof, as will be more apparent from the following detailed description taken in connection with the accompanying drawings.

Brief description of the drawings FIGURE 1 is an exploded isometric view of various parts of the preferred assembly according to the invention, showing the parts in actual size.

FIGURE 2 is an isometric View of the assembled switching device of FIGURE 1 showing the positional relationship of subminiature basic switches incorporated therein.

FIGURE 3 is an isometric view showing the housing in which the assembly is enclosed.

FIGURE 4 is a somewhat enlarged bottom view of the assembly with portions cut away to show internal interfitting of parts of the device.

FIGURES 5 and 6 are enlarged sectional views taken in a longitudinal plane of the assembled device, showing certain internal parts out of the viewing plane and illustrating cooperative relationships of the parts in initial and actuated positions, respectively.

Description of the preferred embodiment Though the principles of the invention are more broad- 1y applicable, the preferred embodiment illustrated in the drawing is based in some respects as to size and arrangement upon the size and features of the subminiature basic switch 10, sometimes referred to as a snap-action switch or microswitch. The working parts and connections of the basic switch are contained in a housing consisting of base portion 12 from which extend three terminals 14, with apertures 16 extending laterally through the housing between the terminals, and a smaller upper portion 18 from which extends the push-button 20 (FIGURE 5). These switches are typically one-half inch in width and 0.2 of an inch thick. Various switching device constructions have been attempted incorporating such basic switches for simultaneous operation, but many have been too large or overly complex. For example, when four such switches are arranged side-by-side to be operated by a common actuator bar extending across the buttons 20, the total width is greater than 0.8 of an inch and some of the terminals, arranged side-by-side, are not easily accessible. Typically, one or more clusters of such switches are included in a single switching device, and in such cases both lateral and longitudinal compactness are of prime importance.

According to this invention, the subminiature switch components are arranged within a 0.7 inch square in housing 22 forming a central cavity in the manner shown in FIGURE 4. The end of each switch bears against the side of the next, with actuator buttons positioned centrally on each side. The housing is shaped internally to receive the switches, with shoulders 25 and 27 positioning them longitudinally. The square cavity formed in the center of the arrangement is occupied by the actuator assembly, which includes locator block 24 holding the switch components 10 in positions tangential to the actuator assembly. The locator block includes a square base portion 26 having outstanding lugs 28 protruding centrally from each side to be received in one of the apertures 16 of each microswitch to hold them in proper relative position during assembly and to secure itself against longitudinal movement after assembly. If less than four microswitches (twelve terminals) are needed, one or more apertured dummies of the same shape can be substituted. The locator block is hollow and further includes a cup portion 30 adapted to receive return spring 32 and having a central aperture 34.

The actuator assembly contained in the central cavity includes a plunger 36 and a flanged actuator member 38 mounted on the plunger between return spring 32 and an actuator spring 40 aligned axially thereon. The actuator member 38 includes an apertured cup portion 42 into which plunger 36 is received, and an annular flange 44 which contacts the symmetrically positioned actuator buttons 20 of the four basic switches 10. Actuator spring 40' beats on one end against the enlarged head portion 46 of the plunger and on the other end against the inside of cup portion 42 of the actuator member. A C-type lock washer 48 keyed in an annular slot 50 in the plunger serves as 4 54 and a shank portion 56 with longitudinal slots 58. The return spring 32 bears against the end 30 of locator block 24 and against a flanged collar 60 and rests against the lock washer 48 on plunger 36 to urge the plunger to its initial position as shown in FIGURE 5.

A flanged, hollow screw 62 is employed to mount the entire assembly upon a panel 64, which may comprise a portion of a larger switch unit (not shown) such as one having illuminated means indicating the operative status of a system operated by the switch. Thus the top 23 of the housing is held against the panel 64 by threading the screw member 62 into the flanged nut 52 against a warped spring-type washer 66. The screw 62 is held against rotation by serrations on its flange or other suitable means.

The plunger head 46 is received in shank portion 56 of the flanged nut 52 and is provided with laterally extending lugs 47 which slide in longitudinal slots 58. On the other end of the plunger is a screwdriver slot 49, accessible through the aperture 34 in locator block 24, by means of which the plunger can be turned to tighten the nut 52 onto the screw 62. The lugs 47 keyed in slots 58 transmit the turning force for mounting of the device, but do not interfere with longitudinal movement of the plunger when the switch is operated.

Basic switches 10, after being assembled on locator block 24 and positioned within the housing 22, are secured within the latter by heat staking external points on the housing corresponding to the positions of apertures 16 in the basic switches. The housing is constructed of suitable thermoplastic material deformable by a pointed instrument heated to a suitable temperature to form flared portions 21 extending into the aperture 16 as shown in FIGURES 4 and 6. The basic switches and locator block 24 are thus secured against longitudinal movement in response to operation of the switch.

An actuator rod 68, which may form a part of a larger switching device or indicator unit as previously mentioned, extends through the hollow screw 62 and bears against the plunger head 46 to depress the plunger 36 against return spring 32. Actuator spring 40 transmits actuation force to actuator member 42, the flange 44 of which in turn depresses buttons 20 of basic switches 10, and also absorbs overtravel force after the buttons are depressed. Return spring 32 also absorbs overtravel force, and it preferably bottoms in the locator block 24 before actuator spring 40 becomes completely depressed. This prevents the full actuation force from being absorbed by the basic switch buttons and reduces wear. The depressed position of the actuator assembly is shown in FIGURE 6.

After the actuator rod 68 is released, return spring 32 returns plunger 36 to its initial position down in FIG- URE 5, while actuator spring 40 returns actuator member 42 to its initial position against washer 48 on plunger 36, and internal springs (not shown) in the basic switches 10 return actuator buttons 20 to their initial positions.

The invention thus provides a switch assembly which is compact in arrangement both laterally and longitudinally, and includes a simple actuator assembly capable of operating all of the basic switches simultaneously. It incorporates means for conveniently securing the assembly to a panel or other portion of a larger switching unit and can be easily removed for replacement. Other advantages and possible modifications of the preferred embodiment will be recognized by those skilled in the art, within the scope of the principles defined in the appended claims.

What is claimed is:

1. An electrical switch assembly comprising a housing, a plurality of button-actuated basic switches arranged within the housing about a common axis so as to form a central cavity and having their actuator buttons directed longitudinally of the axis, and a common actuator for said switches, said actuator including a plunger extending along the axis within said cavity and operable to be moved axially between initial and depressed positions, an actuator member mounted :for relative movement along the plunger between initial and depressed positions and having a flange operable to engage and operate said actuator buttons, a stop on the plunger establishing the initial position for said actuator member, an actuator spring mounted on the plunger to urge the actuator member against said stop and operable to transmit actuation force from the plunger to the actuator member, said actuator spring being adapted to absorb the force of overtravel of the plunger after the switch actuator buttons are depressed, a plunger return spring, and means secured in the housing at one end of said cavity against which said return spring bears to urge the plunger toward its initial position.

2. A plunger-actuated electrical switching device comprising a housing, a plurality of button actuated basic switches arranged within the housing about a common axis so as to form a central cavity, a plunger positioned within said cavity and movable axially from an initial position to a depressed position in response to actuation force applied to one end thereof, a locator member mounted in one end of said cavity, a return spring bearing against said locator member and urging the plunger toward its initial position, an actuator member mounted for relative movement along the plunger between initial and depressed positions thereon, said actuator member having a cup portion positioned within said cavity and a flange extending laterally from the cup portion to engage and operate the basic switch actuator buttons by axial movement, an actuator spring mounted on the plunger within the cup portion of the actuator member, said actuator spring having one end secured to the plunger and the other end bearing against the actuator member to urge the same toward an initial position on the plunger and to transmit actuation force from the plunger to the actuator member, said actuator and return springs being operable to absorb the force of overtravel of the plunger after the basic switch actuator buttons are depressed.

3. The switching device defined in claim 2 wherein said basic switches are contained m'thin a square housing, each having one end positioned in a corner of the housing and the other end bearing against the side of an adjacent basic switch, said switches further having apertures extending laterally therein, said locator member having a plurality of lateral projections thereon each positioned to be received in an aperture in one of said switches, and means securing said switches against axial movement in said housing.

4. The switching device defined in claim 2 wherein the plunger includes an elongated shank portion at one end and at the other end an enlarged head portion positioned substantially within the cup portion of the actuator memher, said cup portion having a base apertured to receive said shank portion slidably therein, and a stop member mounted upon said shank portion on the side of said base opposite the head portion of the plunger, said actuator spring being mounted to bear against the head portion of the plunger at one end to urge the actuator member against said stop at the other end.

5. The switching device defined in claim 4 wherein said return spring is mounted in axial alignment with the actuator spring, having the end thereof opposite said locator member bearing against said stop to urge the plunger toward an initial position away from the locator member.

6. The switching device defined in claim 4 wherein said housing includes an axially positioned aperture adapted to receive an actuator rod to operate the plunger, and first and second flanged fastening elements adapted to receive the actuator rod and to be threaded together from opposite sides of said aperture to secure said device upon a panel, the first fastening element including a shank portion adapted to receive therein the head portion of the plunger and to extend into the cup portion of the actuator member.

7. The switching device defined in claim 6 wherein the shank portion of said first tfastening element includes longitudinal slots and the head portion of the plunger includes lugs extending laterally into said slots and adapted to slide longitudinally therein, the plunger further including means on the end opposite said head portion for receiving a tool capable of rotating the plunger, whereby turning force applied thereto is transmitted to said first fastening element by said lugs.

8. An electrical switching device comprising a housing, a plurality of separate button actuated basic switch components positioned within said housing spaced from a common axis so as to form a central cavity therebetween and having their actuator buttons extending longitudinally of the housing, and an actuator assembly extending into said cavity including a spring biased plunger axially movable within said cavity and an actuator member mounted on said plunger, said actuator member having a laterally extending flange portion adapted to engage the actuator buttons of said switch components in response to axial movement of the plunger and a plunger receiving portion within said cavity coupled to transmit force from said plunger to said flanged portion by longitudinal movement within said cavity.

9. The device defined in claim 8 wherein said switch components are elongated in a cross section thereof transverse to said common axis, and each is positioned to extend in a direction tangential to said actuator assembly with one end positioned adjacent to the side of the next adjacent switch component.

References Cited UNITED STATES PATENTS 2,841,659 l/1958 Eitel 200-6 2,896,034 7/ 1959 Nolden et al 2006 3,277,248 10/ 1966 Melvin 2006 LEWIS H. MYERS, Primary Examiner.

J. R. SCOTT, Assistant Examiner.

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