Linear Cam Slide Switch With Guide Means And Conductive Sheet Contact

Abstract

A switch including a board or the like having a conductive pattern thereon, an insulating material layer supported by the board and having a hole formed therethrough, a conductive resilient and flexible material layer supported by the insulating material layer and adapted to extend through the hole in the insulating material layer upon application of a force thereto, guide means supported on the conductive material layer, an actuating member having button means movable within the guide means and adapted when moved in one direction to force the conductive layer through the hole in the insulating layer to contact the conductive pattern, said actuating member having bearing means for engaging the guide means and adapted to force the button means towards the conductive layer when the actuating member is moved in said one direction.

Description

BRIEF DESCRIPTION OF THE DISCLOSURE

This invention is directed to a new and improved electrical switch and in particular is directed to a new and improved switch construction which may be incorporated in the encoded keyboard devices such as shown in U.S. Patent Applications Ser. No. 145,212 filed May 20, 1971 now U.S. Pat. No. 3,705,267 and Ser. No. 154,752 filed June 21, 1971 now U.S. Pat. No. 3,721,778 both assigned to the assignee of this patent application.

The present invention provides a new and improved switch which may be used for deriving a continuous output without requiring the application of a continuous application of force, i.e., by a finger, to one of the keys of the keyboard. The switch of this invention may be used to indicate an on - off condition or control the operation of circuitry to which the encoded keyboard device is coupled, or for many other control purposes.

The switch construction of this invention is quite compatible with the aforementioned encoded keyboard devices and is easily fabricated at the same time thus greatly reducing construction costs. In addition, the switch uses common components already present in the encoded keyboard devices previously mentioned and thus is quite inexpensive to construct.

The switch of the present invention comprises in its preferred embodiment a slidable actuator supported in a guide member and having means for forcing a conductive, e.g., preferably plastic, layer against a conductive pattern formed on a circuit board or the like. The slidable actuator when moved and slid in one direction is urged in a direction to force the conductive layer into contact with the conductive pattern and is preferably held in place by the action of the conductive layer (also preferably of a resilient material), forcing it against the guide means.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a portion of an encoded keyboard showing the switch according to this invention;

FIG. 2 is a bottom view of the outer frame of the encoded keyboard of this invention;

FIG. 3 is a sectional view taken along lines 3--3 of FIG. 2 with the actuator shown in FIGS. 4A-4C in the OFF position;

FIGS. 4A-4C are side, top and bottom views of the actuator according to the invention;

FIG. 5 is a sectional view taken along lines 3--3 of FIG. 1 with the actuator in the ON position;

FIG. 6 is a top view of the cover and character display shown in FIGS. 1, 3 and 5;

FIG. 7 is a top view of the conductive (plastic) layer shown in FIGS. 3 and 5;

FIG. 8 is a top view of the insulator and separating layer shown in FIGS. 3 and 5; and

FIG. 9 illustrates in a top view the conductive circuit pattern supported on a circuit board as shown in FIGS. 3 and 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference should now be had to FIGS. 1-9 for a description of the preferred embodiment of the switch according to this invention. At 10 there is shown a portion of a keyboard which includes a frame member 11. The frame member 11 is provided with windows 13 and 14. The frame window 11 is preferably constructed of insulating plastic, e.g., nylon or polypropylene.

Underneath the windows 13 and 14 there is provided a flexible insulator material layer 15 preferably of plastic, preferably having a top surface with a low coefficient of friction, e.g., polyester such as MYLAR and having printed indicia or legend under window 14 and thus forming keys of the keyboard 10. In particular a D is shown printed as in FIG. 6. Since the key portion of the keyboard forms no part of the present invention no further description thereof will be presented. If additional information is desired, reference may be had to U.S. Pat. Application Ser. No. 154,752 filed June 21, 1971 in the name of Richard E. Seeger and William J. Lynn and assigned to the assignee of this invention. The entire contents of this Patent Application Ser. No. 154,752 as well as U.S. Pat. Application Ser. No. 145,212 is hereby incorporated herein by reference hereto.

Positioned under the window 13 and between frame 11 and the layer 15 on which it slides, there is provided a switch actuator member 17 having a button like contact projection 17a, a finger pusher projection 17b and a raised projection (preferably tapered or inclined as shown) at 17c.

As shown in FIGS. 1, 2, 3 and 5, the actuator member 17 is positioned in a guide cavity 18 formed in the underside of the frame 11 and is slidable therein. The finger pusher projection extends through the window 13 so that the member 17 is movable from the OFF position shown in FIGS. 1, 2 and 3 (in FIG. 2 the actuator 17 is shown dotted) to the ON position as shown in FIG. 5.

In the OFF position the raised projection 17c is positioned so that it is in the windor 13 and in the ON position, the raised projection 17c is positioned under the frame 18 bottom and pivots to force the button like member 17a downwardly as shown in FIG. 5.

In moving back and forth the button like member 17a is positioned in a slit 19 formed in the indicia layer 15 and is positioned thereby for slidable and pivotal movement.

Positioned below the indicia layer 15 is a conductive sheet or layer 20 which is preferably of a plastic material which is preferably resilient (also elastic) so that it will spring back to its initial position as well as conform to the shape of the electrical contact which it is to engage and also it is preferably flexible.

Additionally, it is preferably of a material having a top surface with a low coefficient of friction so that the button member 17a will easily slide over it if it engages it by penetrating the slit 19.

As used herein the term plastic is meant to include both rubber (natural or synthetic) as well as conventional plastics. The plastic is preferably made conductive by the addition of conductive particles, e.g., metal particles such as silver (preferably in flake form), gold, copper or carbon particles or any combination thereof.

In its most preferred form the conductive layer 20 is constructed of plastic materials containing from 10 to 80 volume percent of metal particles, e.g., silicone rubber filed with silver flake. Examples of other conductive plastics suitable for use in this invention are further disclosed in U.S. Pat. Nos. 3,140,342 and 3,576,387.

It should be understood that in addition to the use of conductive particles used to fill the conductive plastic inert or non-conductive fillers such as silica, talc, etc., may also be incorporated as long as the mechanical and electrical properties are not substantially adversely affected.

Below the conductive layer 20 there is provided an insulating barrier layer 21 (preferably very thin and of plastic material e.g., Mylar) having a window 21a formed therein so that the conductive layer may be forced therethrough to engage electrical contact means such as a conductive circuit pattern 22, e.g., of metal (foil) or conductive plastic ink supported on a board 23. As previously mentioned reference may be had to the aforementioned patent applications for further disclosure of the layer 21 construction as well as typical circuit patterns and board constructions.

In order to make electrical contact, a connector pin 24 is coupled to the pattern 22 which is itself supported in a pin holder 25 coupled to and supported by the underside of the board.

Additionally, a further connector pin 26 may be provided which is directly coupled to the conductive layer 20 so that the conductive layer may act as a common terminal. Thus the contact of the conductive layer with the pattern 22 will complete the circuit between the pins 24 and 26.

Briefly, FIG. 5 illustrates the button like member 17a being urged downwardly as the projection 17c engages the underside of the frame 11. In this ON position of the actuator member 17, the button like member 17a forces the conductive layer through the hole 21a and against the contact 22 to complete the circuit between pins. As another feature of the invention the resiliency of the conductive layer (since it is in compression) also urges the actuator member 17 via layer 21 and button like member supported in slit 19 towards the frame underside thus holding the actuator in place.

Thus it may be observed that the actuator member is slidable in two directions and is positionable in a plane substantially parallel to the top surface of the conductive layer 20. It also pivots downwardly to force the conductive layer through the window 21a of the insulator layer 21 to engage the electrical contact means 22 and pivots back to let the resilient layer 20 to move away from contact 22.

The assembly of the frame 11, the member 17 and the layers 15, 20, 21, 22 and 23 are preferably held together by plastic pins 30 extending from the underside of the frame 11 which in manufacturing are formed with heads 30a (see FIGS. 3 and 5), i.e., by melting the plastic and then cooling it.

Claims

We claim:

1. A switch comprising a resilient and flexible electrically conductive means, a layer of insulation material having a window therethrough on which the bottom of the conductive layer means rests, electrical contact means positioned below said window and guide means supporting a slidable actuator member above said conductive layer means, said actuator member including means for forcing a portion of the conductive layer means through the window into contact with the electrical contact means when slid in one direction above said conductive layer means and permitting the conductive layer means to withdraw from this electrical contact means when slid in another direction above said conductive layer means in which said actuator member both slides and pivots as it is moved to force the conductive layer means against the electrical contact, in which the actuator includes means for causing it to pivot as a portion thereof engages a portion of the guide means in order to force the conductive layer means through the window of the insulation layer and into electrical contact with the electrical contact means, and in which the actuator comprises a finger pusher member to permit it to be manually operated, an inclined member for engagement with a portion of the guide means to pivot it, and an actuating button for forcing the conductive layer means through the window of the insulator layer into contact with said electrical contact means, and in which a flexible material layer is positioned between the guide means and the conductive layer means, said flexible material layer having a slit therein in which the actuating button is positioned.

2. A switch according to claim 1 in which the guide means comprises a frame member having a cavity formed therein in which the actuator member is located for slidable movement and in which the cavity is provided with a window through which the pusher member extends so that it may be manually operated.

3. A switch according to claim 2 in which the conductive layer is of plastic material having electrically conductive particles dispersed therethrough.

4. A switch according to claim 1 in which the conductive layer means comprises plastic material having electrically conductive particles dispersed therethrough.

5. A switch according to claim 4 in which the plastic material is elastic.

6. In a switch comprising an insulative support member having an electrical contact supported thereon, a sheet of insulator material having a window therethrough, said window positioned over at least a portion of the electrical contact, a resilient and flexible plastic layer supporting electrically conductive means positioned above said insulator layer window formed therethrough, an actuator member which slides and pivots when moved to force the conductive means through the window into engagement with the electrical contact or to permit the conductive means to withdraw through the window from engagement with the electrical contact the improvement comprising first guide means for guiding the actuator member, and in which said plastic layer urges the actuator member against the first guide means, means forming a portion of said first guide means causing said actuator to pivot when slid in one direction, the additional improvement comprising a button on said actuator and a flexible material layer having second guide means for guiding said button, said flexible material layer positioned between the second guide means and the plastic layer.

7. In a switch of claim 6 in which second said guide means for said button comprises a slit.

8. In a switch of claim 7 in which the plastic layer is elastic.