GB2043965A - Improvements in or relating to clocks - Google Patents

Abstract

A clock hand 16 of magnetic material is pivoted at the centre of the clock face and driven by a magnet 19 mounted on a ring gear 17 surrounding the face. The face may be transparent, thus giving the impression that the hand is rotating without any apparent clock mechanism, the gear 17 being concealed within a surround 14 of the clock face. The gear 17 is driven by a mechanism 10 within the clock base 12. The hand 16 is freely pivoted on a transparent column 18 and may be a minutes hand driving a further, hours hand by means of an intermittently acting friction coupling at the centre of the face. <IMAGE>

Description

SPECIFICATION Improvements in or relating to clocks The present invention relates to a clock.

According to the present invention, there is provided a clock having a hand of a magnetic material freely pivoted at the centre of a clock face and magnetically driven by a ring disposed about the periphery of the clock face and driven by a clock mechanism.

The ring surrounding the clock face may carry one or more permanent magnets, although it may itself be permanently magnetised. The hand may itself be a magnet, though it suffices for it to be of a material which is attracted by a permanent magnet.

Preferably, the clock face is made of a transparent material.

If it is desired to provide both an hours and a minutes hand, it is possible to provide a friction drive between the minutes hand and the hours hand so that the hours hand is intermittently frictionally driven by the minutes hand. Such a device can be included within a small hub at the centre of the dial.

The invention will now be described further, by way of example, with reference to the accompanying drawing, which illustrates diagrammatically a front elevation partly cut away of a clock in accordance with the invention.

In the accompanying drawing, there is shown a clock which comprises a clock mechanism 10 mounted within a base 12. The clock movement may be of any suitable conventional design and may either be mechanical or electrical. The clock face comprises a surround 14 at the centre of which there is pivotably mounted a single hand 1 6 supported on a transparent column 1 8.

Alternatively, a single piece of circular glass pivotably supporting the hand 1 6 could be used as a clock face.

The surround 14 is in the form of a hollow ring in which a toothed gear ring 1 7 is concealed. On the front face of the surround markings are formed to indicate the hours.

The gear ring 1 7 is driven by the clock movement 10 and carries a permanent magnet 1 9. The magnet 1 9 is illustrated within the cut away in the surround 14. The toothed ring 1 7 is non-ferrous and of square section and is suitably supported to rotate in a vertical plane. The ring rotates at the rate of 12 hours per revolution and the magnetic attraction between the hand 1 6 and the magnet 1 9 rotates the hand 1 6 always to point in the direction of the magnet.

The clock when viewed by an observer will consist only of a ring engraved with the hours -mounted on top of a box which also supports the transparent column carrying the clock hand and there will be no apparent mechanism acting to rotate the clock hand.

Should it be desired to provide two-hands, for the hours and minutes respectively, the hours hand may be driven by the minutes hand through a suitable coupling. A frictional coupling is preferred as it can be made sufficiently compact to be housed in a small hub at the centre of the dial, the hub being too small to accommodate a drive mechanism for both hands.

In such a friction coupling, the hands are mounted on a common shaft and to operate with a stationary cam mechanism, which urges the minutes hand intermittently and to frictional contact with the hours hand so that the hours hand is moved by a predetermined increment every, for example, fifteen minutes. Friction couplings operating on this principle are well known in the art.

1. A clock having a hand of a magnetic material freely pivoted at the centre of a clock face and magnetically driven by a ring disposed about the periphery of the clock face and driven by a clock mechanism.

2. A clock as claimed in Claim 1, wherein the ring carries one or more permanent magnets.

3. A clock as claimed in Claim 1 or 2, in which each hand is of a soft ferro-magnetic material.

4. A clock as claimed in any preceding claim, wherein the clock face is of a transparent material.

5. A clock as claimed in Claim 4, wherein the ring is concealed within a hollow annular surround.

6. A clock as claimed in any preceding Claim, having two hands of which the minutes hand is driven magnetically and the hours hand is driven by the minutes hand.

7. A clock as claimed in Claim 6, in which a friction coupling is provided between the hours hand and the minutes hand, the minutes hand being periodically coupled frictionally to the hours hand to drive the hours hand by a predetermined increment.

8. A clock substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to clocks The present invention relates to a clock. According to the present invention, there is provided a clock having a hand of a magnetic material freely pivoted at the centre of a clock face and magnetically driven by a ring disposed about the periphery of the clock face and driven by a clock mechanism. The ring surrounding the clock face may carry one or more permanent magnets, although it may itself be permanently magnetised. The hand may itself be a magnet, though it suffices for it to be of a material which is attracted by a permanent magnet. Preferably, the clock face is made of a transparent material. If it is desired to provide both an hours and a minutes hand, it is possible to provide a friction drive between the minutes hand and the hours hand so that the hours hand is intermittently frictionally driven by the minutes hand. Such a device can be included within a small hub at the centre of the dial. The invention will now be described further, by way of example, with reference to the accompanying drawing, which illustrates diagrammatically a front elevation partly cut away of a clock in accordance with the invention. In the accompanying drawing, there is shown a clock which comprises a clock mechanism 10 mounted within a base 12. The clock movement may be of any suitable conventional design and may either be mechanical or electrical. The clock face comprises a surround 14 at the centre of which there is pivotably mounted a single hand 1 6 supported on a transparent column 1 8. Alternatively, a single piece of circular glass pivotably supporting the hand 1 6 could be used as a clock face. The surround 14 is in the form of a hollow ring in which a toothed gear ring 1 7 is concealed. On the front face of the surround markings are formed to indicate the hours. The gear ring 1 7 is driven by the clock movement 10 and carries a permanent magnet 1 9. The magnet 1 9 is illustrated within the cut away in the surround 14. The toothed ring 1 7 is non-ferrous and of square section and is suitably supported to rotate in a vertical plane. The ring rotates at the rate of 12 hours per revolution and the magnetic attraction between the hand 1 6 and the magnet 1 9 rotates the hand 1 6 always to point in the direction of the magnet. The clock when viewed by an observer will consist only of a ring engraved with the hours -mounted on top of a box which also supports the transparent column carrying the clock hand and there will be no apparent mechanism acting to rotate the clock hand. Should it be desired to provide two-hands, for the hours and minutes respectively, the hours hand may be driven by the minutes hand through a suitable coupling. A frictional coupling is preferred as it can be made sufficiently compact to be housed in a small hub at the centre of the dial, the hub being too small to accommodate a drive mechanism for both hands. In such a friction coupling, the hands are mounted on a common shaft and to operate with a stationary cam mechanism, which urges the minutes hand intermittently and to frictional contact with the hours hand so that the hours hand is moved by a predetermined increment every, for example, fifteen minutes. Friction couplings operating on this principle are well known in the art. CLAIMS

1. A clock having a hand of a magnetic material freely pivoted at the centre of a clock face and magnetically driven by a ring disposed about the periphery of the clock face and driven by a clock mechanism.

2. A clock as claimed in Claim 1, wherein the ring carries one or more permanent magnets.

3. A clock as claimed in Claim 1 or 2, in which each hand is of a soft ferro-magnetic material.

4. A clock as claimed in any preceding claim, wherein the clock face is of a transparent material.

5. A clock as claimed in Claim 4, wherein the ring is concealed within a hollow annular surround.

6. A clock as claimed in any preceding Claim, having two hands of which the minutes hand is driven magnetically and the hours hand is driven by the minutes hand.

7. A clock as claimed in Claim 6, in which a friction coupling is provided between the hours hand and the minutes hand, the minutes hand being periodically coupled frictionally to the hours hand to drive the hours hand by a predetermined increment.

8. A clock substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.