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US 4,100,728 AGranted
Mechanical digital stopwatch
AssigneeMattel, Inc.
InventorsRichard Shih-Teng Chang, Edmund Emil Landsinger
Life of this patent
Estimating the term…
Abstract
A mechanical spring-powered hand-held digital stopwatch having a gear-operated decade counter display assembly, a spring-powered windup mechanism adapted to reset the counter during winding by means of a unidirectionally activated ratchet assembly, and a cam adjustable timing escapement mechanism, the escapement mechanism including an escapement gear actuating a balance through a limited pivotal angle, the angle of pivoting being governed by cam means interposed between a pair of arms carried by the balance.
Claims6
In a mechanical watch for measuring a period of elapsed time, the combination comprising:
- a housing having a display window;
- spring means within the housing;
- windup means for winding said spring means;
- a decade counter within said housing and having a digital output for displaying in said display window a plurality of digits indicative of the elapsed time measurement;
- a ratchet mechanism operatively connected between said counter and said windup means and responsive to the winding thereof for resetting said counter, said ratchet mechanism including a pawl member coupled with an internally toothed ratchet gear;
- escapement means;
- and
- switch means operable to enable said spring means to actuate said decade counter under control of said escapement means, said pawl member being rotatable with respect to said ratchet gear when said windup means is actuated with said switch means disabled and being rotated with said ratchet gear when said switch means is enabled.
5 more elements
Dependencies are inferred from the claim text.