GB2281444A - Directional control device - Google Patents

Abstract

A directional control device, for example a control button for an electronic game, comprises a rigid key cap 1 and a silicon rubber layer 15 having contact switches 17. Protrusions 14 of the key cap 1 interengage in recesses 21 of the rubber layer 15 above each contact switch 17. The key cap 1 pivots over the convex surface 29 of a stud 28 fixed to a base 25. The interengagement of the protrusions 14 and recesses 21 ensures that when the key cap 1 is depressed above a particular contact switch 17, only that switch is operated. The stud 28 separates the key cap 1 from the rubber layer 15 allowing a relatively large angular movement of the key cap 1 and hence an improved operating feel. <IMAGE>

Description

DIRECTIONAL CONTROL DEVICE This invention relates to a directional control device, and, more particularly, to a directional control button for use, for example, in an electronic game.

A conventional x-y directional control button comprises a key cap which rests on a layer of elastic silicon rubber. The key cap has a hemispherical fulcrum member in the centre of its lower surface which is received in an aperture in the silicon rubber layer so that pressure on an appropriate region of the key cap activates the one of four contact switches with flat tops spaced at 900 intervals around the silicon rubber layer which is below that region.

The dimensional accuracy of silicon rubber is poor and so the conventional directional control button responds inaccurately when only one of the x and y inputs is selected. If the user fails to align the line of action of his finger perpendicular to the plane of the key cap, the considerable disadvantage of both x and y switches being activated at once may result. This may mean, for example, that the output direction deviates by 450 from the original input direction.

It is an object of the invention to provide a directional control device which alleviates the above mentioned disadvantage.

Accordingly, the invention consists in a device for directional control comprising a rigid member, a resilient member having a plurality of spaced contact switches, and means for pivotal mounting of said rigid member with respect to said resilient member, said resilient and rigid members having interengageable elements comprising a protrusion on said rigid member and a recess in said resilient member, both formed in the location of each contact switch such that, when pressure is applied to said rigid member in the region of a particular contact switch, said contact switch is actuated by the interengagement of the associated protrusion in the associated recess. In this manner, when one contact switch is selected, only that switch is actuated.

The rigid member may be a substantially circular key cap and the resilient member may be a substantially disc-shaped resilient layer. The resilient member may be made of elastic silicon rubber.

The pivotal mounting means may comprise an elongate member which is arranged to provide a spacing between said rigid member and said resilient member. The overall length of said elongate member may be greater than half the radius of the key cap. Said elongate member may comprise an elongated stud, fixed to a base on which said resilient member is disposed, and penetrating an aperture in said resilient member. Said elongate member may have a convex surface facing towards said rigid member, said rigid member having a concave surface facing towards said resilient member, and pivoting of said rigid member with respect to said resilient member being achieved by contact between said convex and concave surfaces.

Said concave surface of said rigid member may be formed in the centre of a surface of said rigid member facing said resilient member, said surface facing said resilient member having wall portions radiating outwardly from said concave surface, each towards the location of one of said contact switches.

Each of said protrusions may be a small crossshaped curved protrusion formed at the peripheral end of one of said wall portions.

A projection may be formed on a surface of said rigid member facing away from said resilient member, said projection having an arm running substantially along the line of each wall portion, each arm being arranged to be depressed by a user to actuate the associated contact switch.

In a preferred embodiment, four contact switches are provided, adjacent switch being positioned at 900 to each other about the centre of the resilient member.

The device may comprise a directional control button for an electronic game.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figures la and ib show top and bottom views respectively of a rigid member according to an embodiment of the invention; Figure ic shows a section of the rigid member shown in figure la, taken along the line A-A; Figures 2a and 2b show top and bottom views respectively of a resilient member; Figure 2c shows a section of the resilient member shown in figure 2a, taken along the line B-B; and Figure 3 shows a schematic sectional view of an assembly including the members shown in figures 1 and 2.

Figures la-lc show a rigid key cap 1 which is substantially circular in plan and has an upper surface 2 and a skirt 3 depending therefrom at a slightly obtuse angle and ending in a substantially horizontal annular flange 4.

The upper surface 2 has a cross-shaped projection 5 having two x-direction arms 6 and two y-direction arms 7 at right angles thereto. The arms 6, 7 slope upwards towards the circumference of the key cap 1. In each of the four spaces between the arms 6, 7 is an arrow 8 pointing at *450 thereto.

On the circumference of the flange 4 are four semicircular lugs 9 at the same angular positions as the arrows 8.

On the underside of the cross-shaped projection 5, a cross-shaped wall 10 is provided. The wall 10 has four wall arms 11 projecting radially outwards from the centre of the key cap 1, where they are recessed to provide a composite concave surface 12. Each of the wall arms 11 has, at its outer end which is continguous with the skirt 3, a small cross-shaped section 13. The lower end of each small cross-shaped section 13 is formed as a curved protrusion 14, protruding below the level of the flange 4.

Figures 2a-2c show a silicon rubber layer 15 which is substantially disc-shaped, having a diameter equal to that of the key cap 1. The rubber layer 15 has a central circular aperture 16 the diameter of which is close to the greatest horizontal diameter of the concave surface 12 shown in figures ib and ic.

The rubber layer 15 has four contact switches 17 which consist of discs of a material harder than the silicon rubber. The contact switches are spaced around the rubber layer 15 at equal angular intervals and each is fixed to the lower surface of a cylinder 18 forming an integral part of the layer 15 and is held above a circular switch aperture 19 in the layer 15 by means of a hollow truncated cone 20. Each cylinder 18 has a curved recess 21 in its upper surface, the curved shape and distance from the centre of the layer 15 of which correspond to the curved shape and distance from the centre of the key cap 1 of each curved protrusion 14.

The rubber layer 15 has at its circumference four semicircular lobes 22 at angular positions half way between each two adjacent contact switches 17. The lobes 22 are larger than the lugs 9 shown in figures la - lc.

Figure 3 shows a directional control button in which the key cap 1 and the silicon rubber layer 15 are housed within an enclosure 23. The key cap 1 protrudes through a circular key cap aperture 24 in the enclosure 23.

For the sake of simplicity the cross-shaped projection 5 is not shown in figure 3.

A rigid base 25 consists of a lower solid portion 26 and a contact board 27 on its lower side fixed to the solid portion 26, to the upper side of which the rubber layer 15 is contact switching areas 30 of the contact board 27 is defined within each switch aperture 19 of the layer 15.

A stud 28 fixed to the solid portion 26 penetrates an aperture in the contact board 27 located below the central aperture 16 and through the central aperture 16 itself. The length of the stud 28 is slightly greater than half the radius of the key cap 1 and of the rubber layer 15. The stud 28 has a convex surface 29 corresponding in shape to the concave surface 12 of the key cap 1.

Each curved protrusion 14 rests in one of the curved recesses 21 of the cylinders 18.

This maintains the concave surface 12 just above the convex surface 29 of the stud 28.

To operate the directional control button in purely the x or y direction, the user depresses one of the four arms 6, 7 of the cross-shaped projection 5 of the key cap 1. The entire key cap 1 then moves slightly downwards until the concave surface 12 comes into contact with the convex surface 29 of the stud 28. The key cap 1 then pivots by the sliding contact between the concave and convex surfaces 12, 28, with the arm 6 or 7 being depressed moving downwards.

As has been described, each of the curved protrusions 14 lies below one of the arms 6, 7 and so the curved protrusion 14 below the depressed arm 6 or 7 also moves downwards. To allow this movement, the cylinder 18 having the curved recess 21 in which that curved protrusion rests moves downwards as the truncated cone 20 is compressed.

Eventually the contact switch 17, moving down through the switch aperture 19, comes into abutment with the associated contact switching area 30 and the pressure of the switch 17 on the area 30 actuates the desired operation.

When the user releases the key cap 1, the truncated cone 20 assumes its original shape and restores the key cap 1 to its original horizontal position.

If the user wishes to operate the control button in the x and y directions simultaneously he presses down on the desired arrow 8. The key cap 1 then pivots down on the stud 28 towards that arrow 8, and the contact switches 17 under the arms 6, 7 on either side of the arrow 8 are operated to generate pressure on their respective switching areas 30. The lug 9 at the same angular position as the arrow 8 simultaneously rests on the lobe 22 also at that angular position.

The curved protrusions 14 which engage in the curved recesses 21 accurately operate the individual contact switches 17, and when only one of the x and y directions is selected, only one contact switch 17 will be operated no matter how the user's finger is aligned.

The convex surface 29 of the stud 28, together with the concave surface 12 of the key cap 1, forms a reliable joint and provides higher accuracy. Also, the length of the stud 28 separates the key cap 1 from the rubber layer 16 more than in the conventional control button, which improves the feeling experienced when the key cap 1 is depressed, since the key cap 1 moves through a larger angle.

In the described embodiment of the invention, the dimensional tolerance of silicon rubber is less critical than in the conventional control button. Since the dimensions of the silicon rubber layer are difficult to control, this avoids quality control problems in the manufacturing process.

Whilst a particular embodiment of the invention has been described, modifications may be made thereto without departing from the scope of the invention.

Claims (14)

1. A device for directional control comprising a rigid member, a resilient member having a plurality of spaced contact switches and means for pivotal mounting of said rigid member with respect to said resilient member, said resilient and rigid members having interengageable elements, wherein said interengageable elements comprise a protrusion on said rigid member and a recess in said resilient member, both formed in the location of each contact switch such that, when pressure is applied to said rigid member in the region of a particular contact switch, said switch is actuated by the interengagement of the associated protrusion in the associated recess.

2. A device according to claim 1, wherein the rigid member is a substantially circular key cap.

3. A device according to claim 1 or 2, wherein the resilient member is a substantially disc-shaped resilient layer.

4. A device according to claim 1, 2 or 3, wherein the resilient member is made of elastic silicon rubber.

5. A device according to any preceding claim, wherein the pivotal mounting means comprises an elongate member which is arranged to provide a spacing between said rigid member and said resilient member.

6. A device according to claim 5, when dependent upon claim 2, wherein the overall length of said elongate member is greater than half the radius of the key cap.

7. A device according to claim 5 or 6 wherein said elongate member comprises an elongated stud fixed to a base, on which said resilient member is disposed, and penetrating an aperture in said resilient member.

8. A device according to claim 5, 6 or 7, wherein said elongate member has a convex surface facing towards said rigid member, said rigid member having a concave surface facing towards said resilient member, and pivoting of said rigid member with respect to said resilient member is achieved by contact between said convex and concave surfaces.

9. A device according to claim 8, wherein said concave surface of said rigid member is formed in the centre of a surface of said rigid member facing said resilient member, said surface facing said resilient member having wall portions radiating outwards from said concave surface, each towards the location of one of said contact switches.

10. A device according to claim 9, wherein each of said protrusions is a small cross-shaped curved protrusion formed at the peripheral end of one of said wall portions.

11. A device according to claim 9 or 10, including a projection formed on a surface of said rigid member facing away from said resilient member, said projection having an arm running substantially along the line of each wall portion, each arm being arranged to be depressed by a user to actuate the associated contact switch.

12. A device according to any preceding claim wherein four contact switches are provided, adjacent switches being positioned at 900 to each other about the centre of the resilient member.

13. A device according to any preceding claim, comprising a directional control button for an electronic game.

14. A device for directional control, substantially as described herein with reference to the accompanying drawings.