Tape Rule Assembly with Differential Spring-Drive Systems
First Claim
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1. A tape rule assembly including a length of tape and a wound spring operatively associated with the tape, comprising:
- a housing defining an enclosed space; and
a differential spring-drive subassembly rotatably disposed in the housing enclosed space, the differential spring-drive subassembly operative to tighten the spring around a hub when the tape is extended from the housing;
wherein the hub defines a single, self-contained spindle; and
wherein the enclosed space is uninterrupted by any other spindle.
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Abstract
A tape rule assembly includes differential spring-drive systems for rotating a reel of tape through an angular distance different from the angular distance traveled by a hub carrying a wound spring, relative to the tape rule housing. The differential spring drive systems include planetary and cycloidal drive systems. The tape rules of the present invention are thus made more compact than conventional tape rules.
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Citations
20 Claims
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1. A tape rule assembly including a length of tape and a wound spring operatively associated with the tape, comprising:
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a housing defining an enclosed space; and a differential spring-drive subassembly rotatably disposed in the housing enclosed space, the differential spring-drive subassembly operative to tighten the spring around a hub when the tape is extended from the housing; wherein the hub defines a single, self-contained spindle; and wherein the enclosed space is uninterrupted by any other spindle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A tape rule assembly, comprising:
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a housing; and a cycloidal differential spring-drive system rotatably disposed in the housing; wherein the cycloidal differential spring-drive system includes a reel supporting a length of tape and a hub supporting a coil of spring; and wherein the reel is operatively associated with the housing and the hub so that when tape is extended from the housing, the reel rotates through a different angular distance than does the hub.
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20. A method of minimizing the diameter of a coil of spring disposed around a hub of a tape rule assembly having a housing, comprising:
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creating an enclosed space within the housing uninterrupted by a spindle; and rotatably disposing one of a planetary differential spring-drive system and a cycloidal differential spring-drive system within the enclosed space, such that rotating a reel of a respective differential spring-drive system through a first angular distance causes the hub of the respective differential spring-drive system to rotate through a second angular distance different from the first angular distance.
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Specification