GB2219874A - Shadow clock - Google Patents

Abstract

A clock face has a centrally mounted object. Two light sources are rotated around this object at different angles of incidence to the clock face producing two shadows, one longer than the other. The longer shadow is the minute hand and the shorter shadow is the hour hand. The two light sources are rotated at different rates by a clock mechanism. <IMAGE>

Description

SHADOW CLOCK This idea consists of a clock, where the 'hands' are produced as shadows of a centrally positioned object on the clock face. Lights on stalk-like structures are rotated around the clock face, casting their light on the object which in turn casts a shadow across the clock face.The light producing the hour hand is positioned further from and at a more obtuse angle to the clock face than the minute hand light so as to produce a shorter shadow of the object on the clock face. The lights can be rotated by mechanical or electromechanical means as is common in clock construction. Power can be provided for the lights by internally mounted batteries in the stalk or via slip rings.

Claims (5)

1 A shadow clock consisting of a clock face, a centrally

mounted object, two light sources each at a different angle of incidence to the clock face producing two different length shadows with each light source being rotated around the object at rates dependant on the length of shadow produced to indicate time.

2 A shadow clock as claimed in Claim 1 wherein supports are provided for each light source.

3 A shadow clock as claimed in Claim 1 and Claim 2 wherein a clock mechanism is provided to rotate the light sources around the object and clock face.

4 A shadow clock as claimed in Claim 1 and Claim 2 and Claim 3 wherein a power source is provided for the light sources.

5 A shadow clock substantially as described herein with reference to Figures 1 and 2 of the accompanying drawing.