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Device to control speed and torque of line return in spring drive device

a technology of spring drive and line return, which is applied in the direction of thin material processing, transportation and packaging, filament handling, etc., can solve the problems of chalk line device retraction, and achieve the effect of reducing ensuring safety in the retraction rate of line or cord

Inactive Publication Date: 2003-08-28
GIRTMAN MICHAEL L +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

0015] In accordance with the present invention, a governing device including a return spring and a spool upon which a line or cord is wound, includes on a fixed housing a magnetic or a conductive material is provided and on the rotating portion of the spool respectively either a layer of conductive material or a magnet is p

Problems solved by technology

While this chalk line device operates very satisfactorily, a problem has occurred concerning the retraction of the chalk line device.
The power spring 30 generates such a large force that the chalk line 100 is in some circumstances retracted so rapidly as to cause danger to the operator during the retraction operation.
However, this patent is not directed to a spring drive system.

Method used

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  • Device to control speed and torque of line return in spring drive device
  • Device to control speed and torque of line return in spring drive device
  • Device to control speed and torque of line return in spring drive device

Examples

Experimental program
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Embodiment Construction

[0034] The automatically retractable chalk line device of U.S. Pat. No. 5,920,997 is indicated in the drawings generally at 1. The assembly includes a housing 2, including a housing body portion 3, having a top surface 4, and a vertical wall 5. The housing includes a spring enclosure portion 6, including an arcuate member 7, a bottom plate 8, including vertical portions 9 and 10 is integral with the arcuate portion 7 by means of fasteners or integral molding.

[0035] The housing includes a top assembly 10, including a top member 11, having downwardly extending sides 12. A spool retainer portion 14, includes an extension of body portion 3 indicated at 16, a bottom plate 18, which supports the spool including shoulder 20. Mechanical fasteners 22 hold the assembly together through openings 23, illustrated in FIG. 3.

[0036] A chalk line discharge portion 24 includes downwardly and inwardly extending walls 26 and 28 terminating in a vertical wall 29, having an opening 29a through which the ...

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PUM

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Abstract

A governing device including a return spring and a spool upon which a line or cord is wound, includes on a fixed housing element a magnetic or a conductive material and on the rotating portion of the spool respectively either a magnet or a layer of conductive material is provided. When the line or cord is retracted by the spring, a hysteresis loop is formed in the conductive material by the magnet causing an eddy current which slows down the rate of retraction of the line to provide safety in the rate of return of the line or cord.

Description

I FIELD OF THE INVENTION[0001] This invention relates to a power spring driven retractable line or cord device having eddy current governor control of line or cord return for safety.II BACKGROUND OF THE INVENTION[0002] In U.S. Pat. 5,920,997 granted Jul. 13, 1999 an automatically retractable chalk line device is disclosed including a power spring 30 which engages a gear 44 which in turn is in driving engagement with a spool 90 which winds a chalk line 100 having a chalk line end portion 106.[0003] While this chalk line device operates very satisfactorily, a problem has occurred concerning the retraction of the chalk line device. The power spring 30 generates such a large force that the chalk line 100 is in some circumstances retracted so rapidly as to cause danger to the operator during the retraction operation.[0004] U.S. Pat. No. 4,116,397 discloses a drive arrangement for yarn storage and dispensing units including a winding member 1 rotably mounted on a fixed shaft 3 by a bearin...

Claims

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Application Information

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IPC IPC(8): B44D3/38B65H75/44
CPCB44D3/38B65H75/4442B65H2701/357B65H2403/7254B65H2403/61
Inventor GIRTMAN, MICHAEL L.NEVILLE, BRIAN E.
Owner GIRTMAN MICHAEL L