GB2403067A

GB2403067A - Tilt switch

Info

Publication number: GB2403067A
Application number: GB0314101A
Authority: GB
Inventors: Thomas John Evans; Brian Kenwyn Christie
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-06-18
Filing date: 2003-06-18
Publication date: 2004-12-22
Also published as: GB0314101D0

Abstract

A switch suitable for use as a tilt or movement switch to detect change in orientation of the device, comprises, a contact arrangement including a perimeter wall having a plurality of electrical contacts 5-10, and a moveable contact element 11 retained within the perimeter wall; the movable contact element having a conductive outer surface. The device may be used as a "single pole switch" that is normally closed and switched to open when the device moves and the contact element moves between first and second pairs of contacts of the perimeter wall. Alternatively, the device may be used as a single pole changeover switch.

Description

Switch Device The present invention relates to a switch device and in

particular a switch device suitable for use as a tilt or movement switch to detect change in orientation of the device.

Tilt switch devices are known in the art and disclosed in, for example, US-A-6559396, US-A- 6518523, US-A-6323446, US-A-5610338, US-A-6198059, US-A-6348665 and US-A- 6339199. An improved arrangement has now been devised.

According to a first aspect, the present invention provides a switch device comprising a contact arrangement including a perimeter wall having a plurality of electrical contacts, and a moveable contact element retained within the perimeter wall, the movable contact element having a conductive outer surface; wherein the contact arrangement is configured to permit movement of the movable contact element under gravity, in response to a change in orientation of the device, between a first contact position in which the movable contact element is in contact with a first pair of contacts of the perimeter wall and a second contact position in which the movable contact element is in contact with a second pair of contacts ofthe perimeter wall.

Beneficially, the contact arrangement is configured with three or more perimeter wall contact pairs, providing the device with a corresponding three or more contact positions for the movable contact element. The arrangement is advantageously configured such that tilting of the device about mutually perpendicular axes results in the contact element moving to a different respective contact position. The position of the contact is dependent upon the orientation of the device. Changing the orientation of the device from its rest position causes the movable contact element to move to a new position, and hence change the connection of the contacts of the device.

The normal, at rest orientation of the device, may be with the plane of the perimeter wall in the horizontal, and tilting of the device in either of mutually opposed "x" or "y" axes results in change of the contact configuration for the device. The device may also even be mounted with the plane of the perimeter wall oriented vertically. The operation of the switch device may be configured for different applications by changing the electrical connection between the various perimeter wall contacts. The device may be used as a "single pole switch" that is normally closed and switched to open when the device moves and the contact element moves between first and second pairs of contacts of the perimeter wall. The switch device may be S configured to return to normally closed in the final at rest position. Alternatively, the device may be used as a single pole changeover switch.

The contact member (having diameter or width dimension d) beneficially moves through at least 0.5d between rest contact positions with a first and second pair of contacts. More preferably the contact member moves through Id between rest and contact positions with the first and second pair of contacts. It is preferred that the movable contact element comprises a spherical ball. Beneficially when moving from a first contact position to a second contact position the ball rolls translationally. Beneficially in moving from the first contact position to the second contact position, the ball rolls translationally through at least 0.5 of a complete roll (more beneficially through substantially at least 0.75 of a complete roll).

It is preferred that the pair of contacts defining a respective contact position for the movable contact member taper from a relatively wide mouth portion to a relatively narrow apex portion.

Beneficially, in moving into a rest in contact position the movable contact member passes through the mouth portion and comes to rest at the apex portion in contact with the respective pair of contacts.

Beneficially, the first pair of peripheral wall contacts are different from the second pair of peripheral wall contacts.

The perimeter wall of the contact arrangement beneficially defines an aperture or recess in a substrate, the substrate also serving as a carrier for one or more other electronic or electrical components or devices and/or being provided with electrically conductive tracks connecting with the perimeter wall contacts of the contact arrangement.

In a preferred embodiment, the device has a contact arrangement which is configured with three or more perimeter wall contact pairs providing the device with a corresponding three or more contactpositions forthemovable contact element, such that tilting ofthe device about mutually perpendicular axes results in the contact element moving to respective different contact positions, the contact arrangement including guide means to guide the movable contact element depending upon the direction of tilt of the device.

The guide means may comprise a formation positioned towards the centre of the area bounded by the perimeter wall, and inhibiting the movable contact element from moving in a straight line direction across the area defined by the perimeter wall. domed or contact support and retaining surfaces for the movable contact element may achieve this result.

According to a second aspect, the present invention provides a switch device comprising a contact arrangement including a perimeter wall having a plurality of electrical contacts, and a moveable contact element retained within the perimeter wall, the movable contact element having a conductive outer surface; wherein the contact arrangement is configured to permit movement ofthe movable contact element under gravity, in response to a change in orientation ofthe device, between different contact configurations ofthe movable contact element and the contacts of the perimeter wall, wherein the perimeter wall of the contact arrangement defines an aperture or recess in a substrate, the substrate also serving as a carrier for one or more other electronic or electrical components or devices and/or being provided with electrically conductive tracks connecting with the perimeter wall contacts of the contact arrangement.

Beneficially, the electrical contacts of the perimeter wall are laid by means of a deposition, printing or etching process.

The invention will now be further described in specific embodiments, by way of example only, and with reference to the accompanying drawings, in which: Figure I is a schematic plan view of a switch device in accordance with the invention; Figure 2 is a schematic plan view of a modification to the contact arrangement of Figure 1; and Figure 3 is a schematic side view of the contact arrangement of Figures 1 and 2.

Referring to the drawings, figure 1 shows a tilt switch or movement sensor device 1 comprising a circuit board substrate 2 having formed thereon a network of conductive tracks 3 appropriate to the function of the device. The tracks 3 may be laid by chemical deposition, etching or other means known in the art. An aperture 4 is formed in the circuit board substrate 2 and the perimeter wall of aperture 4 is defined by a ring of perimeter wall electrical contacts 5,6,7,8,9,10. The peripheral wall contacts for part of the electrical circuit defined on the circuit board by the network conductive tracks. The peripheral wall contacts may be laid on the circuit board substrate in a deposition, printing or etching process (or by other means) which may be the same process as the laying of the other tracks 3 in the network. In the arrangement shown in figure 1 contacts 9 and 10 are separated by an insulating bridge 12, as are contacts 6,7.

In the device a metallic spherical ball 11 is retained in the aperture 4 such that it is free to roll over the area bounded by the contact perimeter wall should the device be subject to movement or tilting. The aperture 4 includes four corner apexes 17 for retaining the ball in any one of four 'at rest' positions. The corner apexes close relatively wide mouth portions defined by the contact portions of the peripheral wall which taper from a respective mouth portion to the respective corner apex 17. The ball is retained within the aperture by upper and lower closure surfaces 14,15 (shown most clearly in figure 3). The closure surfaces are convex, the lower surface (15 in figure 3) defining domed raised floor portion centrally of the aperture 4 sloping towards the periphery of aperture 4. The upper surface ( 14 in figure 3) defines a domed lowered ceiling portion centrally of the aperture sloping toward the periphery of the aperture 4. The convex nature of the surfaces 14, 15 ensures that the spherical ball 1 1 always rolls to an at rest position engaged in one of the apexes 17. The convex nature of the surfaces 14,15 also inhibits the spherical ball I 1 from rolling from one apex 17 to a directly opposite apex 17. In certain embodiments the surfaces 14,15 could form, or be provided with, electrical contacts.

When engaged in an at rest position in a respective apex 17 the spherical ball 11 is in contact with a pair of the perimeter wall electrical contacts thereby forming part of the circuit network of the device. In the arrangement shown in figure 1, the spherical ball 11 is in contact with peripheral wall contacts 5 and 10. If the device is moved in the direction of arrow A (or tilted in the direction opposed to arrow A about the longitudinal axis ofthe device), the spherical ball will roll translationally and come to rest in an at rest position engaged in the lower left apex 17 in the drawing. in such an at rest position, the spherical ball will be in contact with peripheral wall contacts 8 and 9. If alternatively, when engaged in the position shown in figure 1 (in contact with contacts S. 10), the device is moved in the direction of arrow B (or tilted in the direction opposed to arrow B about an axis perpendicular to the longitudinal axis ofthe device), the spherical ball will roll translationally and come to rest in an at rest position engaged in the upper right apex 17 in the drawing. in such an at rest position, the spherical ball will be in contact with peripheral wall contacts 5 and 6. the device will therefore change the contact configuration of the ball 11 and peripheral wall contacts of the aperture 4 in response to movement in, and tilting about, mutually perpendicular directions and axes.

In the arrangement shown in figure 1, separate pairs of peripheral wall contacts may have a common contact. For example contacts 5 and 10 form a contact pair when the ball is in the upper left apex 17 of the arrangement shown in figure 1. When the ball 1 1 moves to an at rest position in the upper right apex 17 of the aperture 4 of the embodiment of figure 1 the ball 11 is in contact with peripheral wall contact pair 5 an 6. Contact 5 is therefore common to both contact pairs in this embodiment. By contrast in an at rest position in the lower left apex 17 of aperture 4, the ball 11 is in contact with peripheral wall contact pair 8 and 9. In the embodiment shown in figure 2, contacts 5 and 8 are effectively split by respective insulating spaces or bridges into separate contacts 5a, 5b and 8a, 8b. In such an arrangement each combination of peripheral wall contact pairs contacted by ball 11 in an at rest position includes contacts not included in another pair.

The operation of the device may be configured by changing the electrical connection between the various contacts to tailor the switch configuration and function to a desired application or use. For example, the device may be configured to act as a single pole switch that is normally closed (when the ball is at rest located in contact with a contact pair) goes to open when the ball rolls from the at rest position, and then returns to closed when the ball 11 comes to rest in its new at rest position.

In the embodiments shown the device has been represented as a four position switch. The skilled addressee will readily appreciate that the scope of the invention is not limited to the embodiments shown but is intended to include modifications and variations operating in a similar manner to achieve the benefits of the invention. For example, the number of contacts and at rest positions may be increased or decreased and the degree of curvature of the convex retaining surfaces varied to modify the sensitivity of the device.

Additionally it should be appreciated that a degree of dual axis tilt sensor functionality can be achieved with the device having three only at rest positions for the ball. Additionally, in certain circumstances the ball could be replaced with a conductive puck, slider or other element. Also the device has been primarily described as intended for operation in a configuration orientated substantially horizontally. The device would however have functionality even with the movement plane of the ball being orientated vertically.

Claims

Claims: I. A switch device comprising a contact arrangement including a

perimeter wall having a plurality of electrical contacts, and a moveable contact element retained within the perimeter wall, the movable contact element having a conductive outer surface; wherein the contact arrangement is configured to permit movement of the movable contact element under gravity, in response to a change in orientation of the device, between a first contact position in which the movable contact element is in contact with a first pair of contacts of the perimeter wall and a second contact position in which the movable contact element is in contact with a second pair of contacts of the perimeter wall.
2. A device according to claim 1, wherein the contact arrangement is configured with three or more perimeter wall contact pairs, providing the device with a corresponding three or more contact positions for the moveable contact element.
3. A device according to any preceding claim, wherein the contact arrangement is configured such that tilting ofthe device about mutuallyperpendicular axes results in the contact element moving to respective different contact positions.
4. A device according to any preceding claim, wherein the movable contact element comprises a spherical ball.
5. A device according to claim 4, wherein in moving from a first contact position to a second contact position the ball rolls translationally.
6. A device according to claim 5, wherein in moving from a first contact position to a second contact position the ball rolls translationally through at least 0.5 of a complete roll.
7. A device according to claim 5, wherein in moving from a first contact position to a second contact position the ball rolls translationally through at least 0.75 of a complete roll.

s
8. A device according to any preceding claim, wherein the pair of contacts defining a respective contact position for the movable contact member taper from a relatively wide mouth portion to a relatively narrow apex portion.
9. A device according to claim 8, wherein in moving into a resting contact position, the lo movable contact member passes through the mouth portion and comes to rest at the apex portion in contact with the respective pair of contacts.
10. A device according to any preceding claim, wherein both contacts of the first pair of peripheral wall contacts are different from the contacts ofthe second pair ofperipheral wall contacts.
1 1. A device according to any preceding claim, wherein the perimeter wall of the contact arrangement defines an aperture or recess in a substrate, the substrate also serving as a carrier for one or more other electronic or electrical components or devices and/or being provided with electrically conductive tracks connecting with the perimeter wall contacts of the contact arrangement.
12. A device according to any preceding claim, wherein the movable contact member has a diameter dimension (d) and the contact member moves through at least O.Sd between rest contact positions with the first and second pair of contacts.
13. A device according to any preceding claim, wherein the movable contact member has a diameter dimension (d) and the contact member moves through l.Od between rest contact positions with the first and second pair of contacts.
14. A device according to any preceding claim, wherein the contact arrangement is configured with three or more perimeter wall contact pairs, providing the device with a corresponding three or more contact positions for the movable contact element, such that tilting of the device about mutually perpendicular axes results in the contact element moving to respective different contact positions, the contact arrangement including guide means to guide the movable contact element depending upon the s direction of tilt of the device.
15. A device according to claim 14, wherein the guide means comprises a formation positioned toward the centre ofthe area bounded bythe perimeter wall, and inhibiting the movable contact element from moving in a straight line direction across the area lo defined by the perimeter wall.
16. A switch device comprising a contact arrangement including a perimeter wall having a plurality of electrical contacts, and a moveable contact element retained within the perimeter wall, the movable contact element having a conductive outer surface; IS wherein the contact arrangement is configured to permit movement of the movable contact element under gravity, in response to a change in orientation of the device, between different contact configurations of the movable contact element and the contacts of the perimeter wall, wherein the perimeter wall of the contact arrangement defines an aperture or recess in a substrate, the substrate also serving as a carrier for one or more other electronic or electrical components or devices and/or being provided with electrically conductive tracks connecting with the perimeter wall contacts of the contact arrangement.