Back to results
US 12,158,338 B2Granted
Tape measure with variable preformed stressed spiral spring retraction system
AssigneeMilwaukee Electric Tool Corporation
InventorsOluwatosin T. Kolade, Shih-Chi Chou
Life of this patent
Estimating the term…
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.
Claims7
A system for forming a variably stressed tape measure spiral spring comprising:
- a sheet material;
- a smoothing station;
- a heating station;
- and
- a stressing station configured to form different levels of preformed stress in different portions of the sheet material, the stressing station comprising:
- a bar configured to engage with and deform the sheet material as the sheet material moves around the bar, wherein the bar is movable relative to the sheet material such that a bend radius induced in the sheet material is varied by altering a position of the bar relative to the sheet material;
- wherein the sheet material when wound forms a tape measure spiral spring.
4 more elements
Dependencies are inferred from the claim text.