GB2081510A - Touch pressure switches - Google Patents

Abstract

A touch pressure switch includes a common panel (3) which locates switch activators (5) between a common flexible strip (1) and respective switch elements (7) mounted on a printed circuit board (6) so that pressure on the single panel at an appropriate point activates the underlying switch element (7). Spacers space the panel (3) from the circuit board (6) on which the switches (7) are mounted to allow other circuit components which may be larger in dimension to be mounted thereon. <IMAGE>

Description

SPECIFICATION Improvements in or relating to touch pressure switches The present invention relates to touch pressure switches and in particular the construction of a pressure switch activator panel, which might be an instrument control panel, as an assembly with integral switches of the touch pressure type.

Touch pressure switches are in general of small dimension, especially in depth (i.e. perpendicular to the panel) being mechanically robust and providing a simple ON/OFF action. Variations in design result from differing electrical, mechanical or environmental specifications but a common feature is an operating part having a small movement, normally of less than 1 mm, and being operable by finger pressure.

A typical switch assembly is described in British Patent No. 1 536079. In that arrangement a printed circuit board includes a number of dome-shaped switch elements. There are provided a number of activators, one for each switch, formed in a single actuator member and there is also a thin flexible member having indicia printed on it. Finger pressure on the flexible member at or close to one of the activators operates the respective switch.

It is an object of the invention to provide a touch pressure switch which is an improvement on the known arrangement at least in some circumstances.

According to the invention there is provided a touch pressure switch including a switch element, an activator member, a flexible panel and means adapted to receive and locate said activator between said flexible panel and said switch element such that pressure on said panel presses said activator against said switch element to an extent sufficient to operate the switch.

The invention also embraces a switch panel including a plurality of switches according to the preceding paragraph having a common flexible panel and common means for locating the activator members.

In order that the invention may be clearly understood and readily carried into effect it will now be described by way of example with reference to the accompanying drawings of which Figure la shows a touch pressure switch panel in plan view, Figure 1b shows the same panel in exploded side elevation, Figure 2a shows a single switch in open position and Figure 2b shows the same switch in activated or closed position.

A switch panel incorporating switches in accordance with the invention is shown in plan in Fig. 1 a and in exploded side elevation in Fig. 1 b. Visible in Fig. 1 a is top "graphics" panel 1, which is normally a thin, typically 0.010 inches to 0.015 inches thickness, overlay of transparent material. Suitable materials are polycarbonate, polyester or similar. The panel 1 is processed, by conventional means, to carry legends, markings, transparent windows etc. as required for a particular application.

As can be seen in Fig. 1 b, the overlay 1 is sealed by a suitable adhesive, indicated by layer 2, to an activator panel 3. The panel 3 includes shaped apertures 4 in which are placed activator pads 5. Finally a circuit board 6, of conventional type, includes switch elements or mechanisms 7, together with any other devices required such as illuminating devices (filament lamps or LED's) or read out devices. Each mechanism is situated adjacent a respective activator pad and the cooperating combination of mechanism 7, pad 5 and any markings on overlay 1 comprise a single touch pressure switch.

A single switch is shown in more detail in Fig. 2a in open position and in Fig. 2b in closed position, to better illustrate its operation.

It can be seen from these Figures that the activator 5 is in this example a single member which can be considered to comprise two portions. A generally flat portion 8 is adapted to receive finger pressure and a portion 9 adapted to press on mechanism 7 when moved by finger pressure on portion 8. Similarly panel 3 includes a recess 10 to receive flat portion 8 and then aperture 4 is of dimensions to allow only portion 9 to protrude to switch mechanism 7. In the relaxed or open position of Fig. 2a the activator 5 is at maximum spacing from the switch mechanism 7 with layer 1 being flat. This may be achieved by resilience in the switch mechanism being sufficient to hold the activator off.

Alternatively a separate resilient device (not shown) may be added for this purpose or the activator may be bonded at its centre to panel 1 to use the resilience of the panel to hold it off mechanism 7.

In operation, as shown in Fig. 2b depression of panel 1 above the chosen switch presses portion 8 and thereby pushes the portion 9 of activator 5 into contact with the mechanism 7 through the small distance required to operate the switch. The recess 10 is of sufficient extent to allow the necessary degree of depression of flat portion 8 but no more and this correspondingly limits the allowed motion of portion 9 and prevents overstressing of the switch mechanism.

It will be appreciated that different lengths of activator portions 9 will allow the activator panel 3 to be spaced at different distances from circuit board 6. This allows the inclusion of the mounting on the same board 6 of various devices such as lamps, display devices and integrated circuits which may be greater in height than the switching elements. Spacing may be achieved by suitable spacer members 11 and adaptation of the switch to different purposes requires only the adjustment of activators 5 and spacer members 11.

In the prior art arrangements it has in contrast been usual to separate the switches with associated printed circuits into an integrated front panel assembly using a suitable electrical connector to make contact with the main instrument circuit board. The present invention in most cases eliminates the need for such a connector and allows greater flexibility in layout design of an instrument incorporating the switches. Furthermore a single panel may include different designs of switches, perhaps having different heights by corresponding choice of the dimensions of their portions 9.

It may additionally be noted that since the activators 5 are separately formed, instead of being part of a common sheet, the risk of operation of one switch affecting an adjacent one is removed.

It will be understood that the embodiment illustrated shows an application of the invention in one form only for the purposes of illustration. In practice the invention may be applied to many different configurations, the detailed embodiments being straightforward for those skilled in the art to implement.

Claims (11)

1. A touch pressure switch including a switch element, an activator member, a flexible panel and means adapted to receive and locate said activator between said flexible panel and said switch element such that pressure on said panel presses said activator against said switch element to an extent sufficient to operate the switch.

2. A switch according to Claim 1 including means adapted to limit the travel of the activator member in response to said pressure.

3. A switch according to Claim 2 in which the limiting means is incorporated in said receiving and locating means.

4. A switch according to Claim 3 in which the receiving and support means is formed with a recess allowing a limited motion of one portion of the activator member and an aperture allowing another portion of the activator member to protrude therethrough to press against said switch mechanism to an extent determined by said limited motion.

5. A switch according to any preceding claim in which the switch element is mounted on a circuit board and including at least one spacer mounting said receiving and locating means at a predetermined distance above said board to allow space for circuit components, including said switch elements, to be mounted thereon.

6. A touch pressure control switch including a switch element, an activator member, a flexible panel and an activator panel locating the activator member between the switch element and the flexible panel.

the activator panel being formed with an aperture through which a portion of said activator member protrudes to be capable of contacting said switch member and a recess allowing a limited motion of another portion of the activator member and thereby limiting motion of the first mentioned portion, the arrangement being such that pressure on said panel presses said activator member against said switch element to an extent sufficient to cause operation thereof but limited by the dimension of said recess.

7. A switch according to Claim 6 in which the switch element is mounted on a circuit board and including spacer means adapted to space the activator panel from the switch element, the dimensions of the activator member being so related to the dimensions of the spacer means to allow sufficient but not excessive pressure on said switch element.

8. A touch pressure switch activator panel including a plurality of switches according to any of the preceding claims, each switch having an individual activator member and switch element and all switches having in common the flexible panel and common means locating the activator member in respective apertures therein.

9. A touch pressure switch activator panel including a circuit board, a plurality of switch elements mounted on said circuit board, a plurality of activator members, a common activator panel locating the activator members each relative to a respective switch element and a flexible panel overlying the activator panel, the activator panel being formed with a plurality of recesses within each of which one activator member is seated to be capable of a limited motion and within the recess an aperture through which a part of the activator member protrudes to contact the respective switch member, the arrangement being such that, an depression of the flexible panel in contact with an activator member, said activator member moves to an extent sufficient to operate the respective switch element. 4

10.A touch pressure switch substantially as herein described with reference to the accompanying drawings.

11. A touch pressure switch activator panel including: a circuit board having mounted thereon a plurality of switch elements together with one or more integrated circuits and or move display devices; a plurality of activator members; a common activator panel locating the activator members each relative to a respective switch element; spacer means spacing the activator panel from the circuit board to an extent sufficient to accommodate the switch element and the integrated circuits and display devices which may be of greater dimension than the switch elements; and a flexible panel overlying the activator panel; wherein the activator panel is formed with a plurality of recesses within each of which one activator member is seated to be capable of a limited motion and within the recess an aperture through which a part of the activator member protrudes to contact the respective switch member, the arrangement being such that, on depression of the flexible panel in contact with an activator member, said activator member moves to an extent sufficient to operate the respective switch element.

1 2. A touch pressure switch substantially as herein described with reference to the accompanying drawings.

1 3. A touch pressure switch activator panel substantially as herein described with reference to the accompanying drawings.

11. A touch pressure switch activator panel substantially as herein described with reference to the accompanying drawing.

CLAIMS (16Jul1981)

1. A touch pressure switch including a switch element mounted on a circuit board, an activator member, a flexible panel, means adapted to receive and locate said member activator between said flexible panel and said switch element and at least one spacer mount ing said receiving and locating means at a predetermined distance above said circuit board to allow space for circuit components including said switch element to be mounted thereon, the arrangement being such that pressure on said panel presses said activator against said switch element to an extent sufficient to operate the switch.

2. A switch according to Claim 1 including means adapted to limit the travel of the activator member in response to said pressure.

3. A switch according to Claim 2 in which the limiting means is incorporated in said receiving and locating means.

4. A switch according to Claim 3 in which the receiving and locating means is formed with a recess allowing a limited motion of one portion of the activator member and an aperture allowing another portion of the activator member to protrude therethrough to press against said switch mechanism to an extent determined by said limited motion.

5. A touch pressure control switch including a switch element mounted on a circuit board, an activator member, a flexible panel, an activator panel locating the activator member between the switch element and the flexible panel and spacer means spacing the activator panel from the circuit board to an extent sufficient to allow mounting on the circuit board of circuit components in addition to said switch element, wherein the activator panel is formed with an aperture through which a portion of said activator member protrudes to be capable of contacting said switch member and a recess allowing a limited motion of another portion of the activator member and thereby limiting motion of the first mentioned portion to an extent which, taking into account the dimensions of said portion and said spacer means, allows pressure on said panel to press said activator member against said switch element to an extent sufficient to operate said switch but is limited by the dimension of said recess to prevent excessive pressure on said switch element.

6. A touch pressure switch activator panel including a plurality of switches according to any of the preceding claims, each switch having an individual activator member and switch element and all switches having in common the flexible panel and common means locating the activator member in respective apertures therein.

7. A touch pressure switch activator panel including a circuit board, a plurality of switch elements mounted on said circuit board, a plurality of activator members, a common activator panel locating the activator members each relative to a respective switch element a flexible panel overlying the activator panel and spacer means spacing the activator panel from the circuit board to an extent sufficient to allow the mounting on said circuit board of circuit components additional to said switches, the activator panel being formed with a plurality of recesses within each of which one activator member is seated to be capable of a limited motion and within the recess an aperture through which a part of the activator member protrudes to contact the respective member, the arrangement being such that, on depression of the flexible panel in contact with an activator member, said activator member moves to an extent sufficient to operate the respective switch element.

8. A touch pressure switch panel according to any of the preceding claims in which the said circuit components include integrated circuits.

9. A touch pressure switch panel according to any of the preceding claims in which the said circuit components include indicator devices.

10. A touch pressure switch panel according to claim 7 in which the indicator devices include lamps.