GB2286011A

GB2286011A - Friction hinge

Info

Publication number: GB2286011A
Application number: GB9401427A
Authority: GB
Inventors: David Southward
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-01-26
Filing date: 1994-01-26
Publication date: 1995-08-02
Also published as: GB9401427D0

Abstract

A hinge comprises a tapered shaft 10 received in a sleeve 12 having a correspondingly tapered inner bore. The shaft 10 is held in the sleeve 12 by means of a screw 18 which enables the frictional torque of the hinge to be set by controlling the compression of a number of disc springs 16. The hinge may be used to mount a computer display screen to the computer main housing. <IMAGE>

Description

Title: Hinqe for Portable Computer and the like Field of the Invention This invention concerns a hinge which may be used, for example, to support the display screen of a laptop computer.

Backqround to the Invention The present hinge design that is used to provide fold away display screens in such devices is well known. The hinge relies on a spring that rides on a shaft. The fold away screens ensure ready portability with minimal risk of damage to the computer screen.

These hinges have enabled the screen to be positioned at varying angles. However the action of the hinge is jerky, non-adjustable and prone to wear.

It is an object of the present invention to provide a hinge which is sufficiently stiff to support the screen display at any angle but yet is free enough to enable ease of alteration from a closed position to an open position and vice versa.

Summary of the Invention According to one aspect of the present invention a two part hinge for supporting a hinged member relative to a fixed member comprises two relatively rotatable components and adjustable force means for urging the two components into frictional engagement, said adjustment enabling the frictional braking force to be adjusted to enable rotation of the two components under an applied force greater than the turning movement about the hinge axis generated by the weight of the hinged member acting about the hinge axis.

In one embodiment the two components are generally cylindrical and are complementarily tapered and comprise a tapered shaft which fits within an internally tapered surrounding sleeve.

Adjustment of the frictional resistance is achieved by axially forcing the one component towards the other to a greater or lesser extent.

By appropriate adjustment the hinged member can be positioned at any one of a range of angular positions around the hinge axis at which it will remain fixed. The hinged member may comprise a lid of a shallow computer casing containing a computer display therein. A hinge as aforesaid may be mounted at opposite sides of the hinged member to provide better support thereto.

The force means may comprise compression spring means, such as a disc spring, and the degree of compression may be achieved by adjustment of the position of a thrust member acting axially on the spring. Typically this is achieved by adjustment of a screw threaded member.

In an embodiment of the invention employing screw means to adjust the thrust member and compress the spring means, the friction brake characteristics are adjustable for example during the manufacturing process, so as to permit stiffness of the hinge joint movement to be selected.

This allows for the support of different weight lids without any other adjustment, such as alteration of the taper angle of the shaft, being necessary.

Preferably the aforesaid frictional characteristics are essentially the same whether the hinged member is being opened or closed.

Ideally the coefficient of friction between the shaft and the sleeve should remain constant throughout the lifetime of the hinge. This may be achieved by bonding a solid lubricant to the surface of either the shaft or the sleeve, or both.

Solid lubricants based on graphite or molybdenum disulphide may be employed. These lubricants result in a coefficient of friction of around 0.125 which is largely independent of the material with which the shaft mates.

The configuration of the taper and sleeve is preferably selected to achieve as large a surface area as possible in order to produce low wear rate, thus extending the life of the brake.

According to another aspect of the invention a computer housing having a hinged lid containing inter alia a display panel or screen is hinged to the remainder of the housing by means of a hinge as aforesaid.

The invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 is a section through a hinge constructed brake in accordance with the invention, and Figure 2 is a side view cf part of a computer having a hinged lid containing a display screen, attached to the computer housing by hinges such as shown in Figure 1.

Detailed description of the illustrated embodiment Figure 1 shows a complete hinge formed by two components frictionally engaged and relatively rotatable about a common axis. A tapered shaft (10) is received in a sleeve (12). The sleeve is attached to a bracket (14). A stop for the hinge is provided comprising a steel pin (20) set into the shaft and a tag (22) bent from the bracket. This ensures that the hinged posts cannot be rotated through more than a given angle, so that for example a lid, attached to a computer housing, is also limited in the amount by which it can be rotated relative to the base.

Thus for example the lid cannot move beyond a present position, typically at 180 degrees to the computer base.

A screw (18) enables the frictional torque of the hinge to be set by controlling the compression of a plurality of disc springs (16). A hardened button washer (28) and a shim (30) on opposite sides of the disc springs prevent wear which would otherwise occur as the screw rotates relative to the bracket.

Rotation of the tapered shaft in the sleeve allows the angle of the lid and therefore a display screen therein to be varied so as to avoid glare from incident light, while the friction therebetween allows the screen to be locked into any selected position during use of the computer.

The angle on the taper affects the amount of spring force resolved normal to the surface of the taper and hence the resultant frictional resistance displayed by the hinge.

Thus for a smaller taper angle, there will be a greater multiplication of the spring force and so a heavier lid can be held in position.

For a taper on the shaft of 5 degrees, there will be an effective multiplication of 11.5 of the spring force.

Figure 2 shows a side view of the hinge when attached to the body of a computer (26) and a display screen (24).

The aforesaid bracket is firmly attached to the body of the computer, with the display screen being attached to the shaft (10). A force applied to the lid will cause movement of the lid about the shaft axis, provided the force is greater than the combined frictional braking effect of the engaging components of the two hinges at opposite ends of the axis about which the lid can pivot.

Claims

1. A two part hinge for supporting a hinged member relative to a fixed member comprising two relatively rotatable components and adjustable force means for urging the two components into frictional engagement, said adjustment enabling the frictional braking force to be adjusted to enable rotation of the two components under an applied force greater than the turning movement about the hinge axis generated by the weight of the hinged member acting about the hinge axis.

2. A two part hinge according to claim 1, wherein the two components are generally cylindrical and are complementarily tapered and comprise a tapered shaft which fits within an internally tapered surrounding sleeve.

3. A two part hinge according to claim l or claim 2, wherein the hinged member is positioned at any one of a range of angular positions around the hinge axis at which the hinged member remains fixed.

4. A two part hinge according to any of claims 1, 2, or 3, wherein the force means comprises compression spring means, and the degree of compression is achieved by adjustment of the position of a thrust member acting axially on the spring means.

5. A two part hinge according to claim 4, wherein screw means is employed to adjust the thrust member and compress the spring means.

6. A two part hinge according to any of claims 2 to 5, wherein the coefficient of friction between the shaft and the sleeve remains constant throughout the lifetime of the hinge.

7. A two part hinge according to any of the preceding claims, wherein the friction brake characteristics are adjustable to permit stiffness of the hinge joint movement to be selected.

8. A two part hinge according to any of the preceding claims, wherein the friction brake characteristics are essentially the same whether the hinged member is being opened or closed.

9. A computer housing having a hinged lid containing inter alia a display panel or screen, wherein the lid is hinged to the remainder of the housing by means of a two part hinge according to any of claims 1 to 8.

10. A two part hinge substantially as herein particularly described with reference to and as illustrated in the accompanying drawings.