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US 12,429,321 B2Granted
Tape measure with variable preformed stressed spiral spring retraction system
AssigneeMilwaukee Electric Tool Corporation
InventorsOluwatosin T. Kolade, Shih-Chi Chou
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Abstract
A tool, such as a tape measure, including a spring-based retraction system is shown. The spring-based retraction system is driven by a spiral spring, that has a variable preformed stress profile along the length of the spring.
Claims8
A system for forming a variably stressed spiral spring for a tape measure, the system comprising:
- a supply of a ribbon material;
- a smoothing station including a pair of calendaring rollers;
- an end roller;
- a heating station positioned between the smoothing station and the end roller;
- a storage device;
- and
- a stressing station positioned between the end roller and the storage device, the stressing station configured to form different levels of preformed stress in different portions of the ribbon material as the material passes through the stressing station;
- wherein the storage device includes an arbor configured to store the ribbon material when wound to form a spiral spring.
5 more elements
Dependencies are inferred from the claim text.