Tape measure with magnetic retraction speed controller

Patent metadata

Field	Value
Publication number	US-11408718-B2
Application number	US-202017109913-A
Country	US
Kind code	B2
Filing date	Dec 2, 2020
Priority date	Jul 12, 2019
Publication date	Aug 9, 2022
Grant date	Aug 9, 2022

Abstract

A tool, such as a tape measure, including a retraction system is shown. The tape measure includes a magnetic retraction speed controller. The magnetic retraction speed controller includes a magnet that induces an eddy current in a conductive component of the tool and slows a retraction speed.

First claim

What is claimed is:

1. A tape measure comprising:
a housing;
a tape reel rotatably mounted within the housing;
a tape blade wound around the tape reel and extendible from the housing;
a hook assembly coupled to an outer end of the tape blade;
a spring coupled to the tape reel, wherein, as the tape blade is unwound from the tape reel to extend from the housing, the spring stores energy, and wherein the spring releases energy driving rewinding of the tape blade on to the tape reel; and
a magnetic retraction speed control system comprising:
a conductive element supported within the housing; and
an array of magnetic material arranged within the housing and positioned relative to the conductive element such that rotation of the tape reel generates relative movement between the conductive element and the array of magnetic material induces eddy currents within the conductive element such that a retraction speed of the tape reel during rewinding is reduced.

2. The tape measure of claim 1 , wherein the conductive element is located on the tape reel and the array of magnetic material is coupled to an inner surface of the housing.

3. The tape measure of claim 2 , wherein the tape reel is formed from a polymer material and the conductive element is a plate of conductive metal material coupled to an outer surface of a side flange of the tape reel.

4. The tape measure of claim 3 , further comprising a gap located between an outer surface of the plate of conductive metal material and an opposing face of a magnet of the array of magnetic material, the gap defining a clearance distance measured between an outer surface of the conductive metal material and the opposing face of the magnet of the array of magnetic material in a direction of an axis of rotation of the tape reel.

5. The tape measure of claim 4 , wherein the clearance distance is between 0.5 mm and 5 mm.

6. The tape measure of claim 1 , wherein the array of magnetic material comprises a plurality of individual magnets arranged in an arch having a total angular arc length of less than 180 degrees.

7. The tape measure of claim 6 , wherein the total angular arc length is between 60 degrees and 120 degrees.

8. The tape measure of claim 1 , wherein the array of magnetic material comprises a plurality of individual magnets arranged in an arch having an angular spacing between adjacent magnets in the arch of between 5 degrees and 60 degrees.

9. The tape measure of claim 8 , wherein the angular spacing between adjacent magnets in the arch is between 15 degrees and 30 degrees.

10. The tape measure of claim 8 , wherein the plurality of individual magnets are spaced a radial distance from an axis of rotation of the tape reel of between 15 mm and 40 mm.

11. The tape measure of claim 1 , wherein the array of magnetic material comprises a plurality of individual magnets each having a cylindrical shape and a diameter of between 5 mm and 15 mm.

12. The tape measure of claim 1 , wherein the conductive element is one of steel, copper, aluminum, silver or gold and a magnetic material of the array of magnetic material is a rare earth magnetic material.

13. A tape measure comprising:
a housing;
a tape reel rotatably mounted within the housing;
a tape blade wound around the tape reel and extendible from the housing;
a retraction mechanism configured to drive rotation of the tape reel to provide retraction of the tape blade; and
a magnetic retraction speed control system comprising a magnet arranged within the housing such that rotation of the tape reel induces an eddy current within a conductive material located inside of the housing.

14. The tape measure of claim 13 , wherein the retraction mechanism comprises a spring coupled to the tape reel, wherein, as the tape blade is unwound from the tape reel to extend from the housing, the spring stores energy, and wherein the spring releases energy driving rewinding of the tape blade on to the tape reel.

15. The tape measure of claim 13 , wherein the conductive material is a conductive metal plate coupled to one of the tape reel and an inner surface of the housing and the magnet is one of an array of magnets coupled to the other of the tape reel and the inner surface of the housing.

16. The tape measure of claim 15 , wherein the array of magnets comprises a plurality of individual magnets arranged in an arch having a total angular arc length of less than 180 degrees and having an angular spacing between adjacent magnets in the arch of between 5 degrees and 60 degrees.

17. The tape measure of claim 16 , wherein the plurality of individual magnets are spaced a radial distance from an axis of rotation of the tape reel of between 15 mm and 40 mm, and wherein the plurality of individual magnets each have a width dimension of between 5 mm and 15 mm.

18. A measuring tool comprising:
a housing;
a reel rotatably mounted within the housing;
a coilable measuring component wound around the reel and extendible from the housing;
a retraction mechanism configured to drive rotation of the reel to provide retraction of the coilable measuring component; and
a magnetic retraction speed control system comprising a magnet positioned in the housing such that rotation of the reel induces eddy currents within a conductive material located inside of the housing such that a retraction speed of the reel during retraction is reduced.

19. The measuring tool of claim 18 , wherein the coilable measuring component is an elongate tape blade and the retraction mechanism comprises a spring coupled to the reel, wherein, as the elongate tape blade is unwound from the reel to extend from the housing, the spring stores energy, and wherein the spring releases energy driving rewinding of the elongate tape blade on to the reel.

20. The measuring tool of claim 18 , wherein the conductive material is a conductive metal plate coupled to one of the reel and an inner surface of the housing and the magnet is one of an array of a plurality of magnets coupled to the other of the reel and the inner surface of the housing.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Mckinster Scott Earl

Classifications

• G01B3/1003 Primary

  characterised by structure or material; characterised by layout or indicia · CPC title

• G01B3/102 Primary

  Means for damping · CPC title

• G01B2003/103

  operated by springs · CPC title