Tape measure with epicyclic gear drive for tape retraction

Patent metadata

Field	Value
Publication number	US-12017885-B2
Application number	US-202217872765-A
Country	US
Kind code	B2
Filing date	Jul 25, 2022
Priority date	Mar 22, 2017
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A tool, such as a tape measure, including a spring-based retraction system is shown. The retraction system utilizes an epicyclic gear train coupled between the tape blade winding reel and a rotating arbor or axle within the tape measure. A spiral spring has an outer end coupled to the reel and an inner end coupled to the axle. The gear train may be a reduction gear train such that the axle rotates slower than the reel. By coupling the spiral spring between the gear train input and gear train output, high energy density springs may be used, which may allow for decrease in housing size, increase in tape length or thickness for a given housing size, and/or advantageous retraction speed control.

First claim

What is claimed is:

1. A tape measure comprising:
a housing;
an axle rotatably mounted within the housing;
a tape reel rotatably mounted within the housing around the axle, the tape reel comprising a radially outward-facing surface;
an elongate tape blade wound around the radially outward-facing surface of the tape reel, both the axle and the tape reel rotating within the housing during extension and rewinding of the elongate tape blade with respect to the housing;
a hook coupled to an outer end of the elongate tape blade;
a retraction system configured to drive rewinding of the elongate tape blade on the tape reel; and
a gear train comprising an input coupled to the tape reel and an output coupled to the axle, wherein the retraction system and the gear train are configured to provide a pre load torque between the tape reel and the axle between 0.5 and 2.5 in-lbf.

2. The tape measure of claim 1 , wherein the gear train is configured such that a Spring Turn Ratio is greater than 1.

3. The tape measure of claim 1 , wherein the retraction system and the gear train are configured to rotate the tape reel at a rotation speed of between 500 rpm and 900 rpm during retraction.

4. The tape measure of claim 1 , wherein the input of the gear train comprises a first rotatable component coupled to the tape reel and the output of the gear train comprises a second rotatable component coupled to the axle.

5. The tape measure of claim 1 , wherein the tape reel comprises a radially inward-facing surface that engages a radially outward-facing of the axle.

6. The tape measure of claim 1 , wherein during extension of the elongate tape blade from the housing, a ratio of tape reel rotations to axle rotations is greater than 1.2:1 and less than 1.5:1.

7. The tape measure of claim 1 , wherein a maximum torque generated by the retraction system reacting between the tape reel and the axle is between 6 and 12 in-lbf.

8. The tape measure of claim 1 , wherein the gear train comprises:
an outer ring gear rigidly coupled to the tape reel;
an inner ring gear rigidly coupled to the axle;
a plurality of posts rigidly coupled to the housing; and
a plurality of planetary gears rotatably mounted to the plurality of posts, the plurality of planetary gears each comprising a low gear section and a high gear section, wherein the low gear section rotatably engages with the inner ring gear and the high gear section rotatably engages with the outer ring gear.

9. The tape measure of claim 8 , wherein each low gear section has a smaller outer diameter than each high gear section.

10. The tape measure of claim 1 , wherein the gear train comprises a first planetary gear train located on a first side of the tape reel and a second planetary gear train located on a second side of the tape reel.

11. A tape measure comprising:
a housing;
an axle rotatably mounted within the housing;
a tape reel rotatably mounted within the housing around the axle, the tape reel comprising a radially outward-facing surface;
an elongate tape blade wound around the radially outward-facing surface of the tape reel, both the axle and the tape reel rotating within the housing during extension and rewinding of the elongate tape blade with respect to the housing;
a hook coupled to an outer end of the elongate tape blade;
a retraction system configured to drive rewinding of the elongate tape blade on the tape reel; and
a gear train comprising an input coupled to the tape reel and an output coupled to the axle;
wherein a maximum torque generated by the retraction system reacting between the tape reel and the axle is between 3 and 20 in-lbf.

12. The tape measure of claim 11 , wherein the retraction system and the gear train are configured to rotate the tape reel at a rotation speed of between 200 rpm and 1500 rpm during retraction.

13. The tape measure of claim 11 , wherein the tape reel comprises a radially inward-facing surface that engages a radially outward-facing of the axle.

14. The tape measure of claim 11 , wherein the retraction system and the gear train are configured to provide a pre load torque between the tape reel and the axle between 1.0 and 1.4 in-lbf.

15. The tape measure of claim 11 , wherein the axle comprises a gear carrier that extends radially outward from an end of the axle, the gear carrier comprises a plurality of posts extending along an axis parallel to a primary axis of the axle, and the gear train comprises:
a sun gear fixedly coupled to the housing;
an outer ring gear coupled to the tape reel; and
a plurality of planetary gears rotatably mounted to the plurality of posts, the plurality of planetary gears rotatably engaging with the outer ring gear and the sun gear.

16. A tape measure comprising:
a housing;
an axle rotatably mounted within the housing;
a tape reel rotatably mounted within the housing around the axle, the tape reel comprising a radially inward-facing surface defining an interior reel cavity and a radially outward-facing surface;
an elongate tape blade wound around the radially outward-facing surface of the tape reel;
a spring located within the interior reel cavity, the spring comprising an outer end coupled to the tape reel and an inner end coupled to the axle, wherein, when the elongate tape blade is unwound from the tape reel to extend from the housing, the spring stores energy, and the spring releases energy driving rewinding of the elongate tape blade on to the tape reel;
a retraction system configured to drive rewinding of the elongate tape blade on the tape reel; and
a gear train comprising an input coupled to the tape reel and an output coupled to the axle;
wherein during extension of the elongate tape blade from the housing, a ratio of tape reel rotations to axle rotations is greater than 1.1:1 and less than 1.6:1.

17. The tape measure of claim 16 , wherein the retraction system and the gear train are configured to provide a pre load torque between the tape reel and the axle between 1.0 and 1.4 in-lbf.

18. The tape measure of claim 16 , wherein the input of the gear train comprises a first rotatable component coupled to the tape reel and the output of the gear train comprises a second rotatable component coupled to the axle.

19. The tape measure of claim 16 , wherein the retraction system and the gear train are configured to rotate the tape reel at a rotation speed of between 500 rpm and 900 rpm during retraction.

20. The tape measure of claim 16 , wherein a maximum torque generated by the retraction system reacting between the tape reel and the axle is between 6 and 12 in-lbf.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Vitas Jonathan F
• Herritz Devin W
• Mckinster Scott Earl

Classifications

• G01B2003/103

  operated by springs · CPC title

• G01B2003/1023

  Winding mechanisms · CPC title

• G01B3/1056

  Tape end arrangements, e.g. end-hooks · CPC title

• G01B3/1041

  characterised by casings · CPC title

• G01B3/1005 Primary

  Means for controlling winding or unwinding of tapes · CPC title