Coilable rule with automatic recoil
First Claim
Patent Images
1. A length measuring instrument comprising:
- a housing;
a spool mounted for rotation in the housing;
a measuring tape mounted on the spool;
an electrical motor for rotating the spool to wind the tape thereon; and
a reduction mechanism between the motor and the spool;
said instrument characterised in that the housing provides a nonrotatable hollow hub and the motor and reduction mechanism are disposed within the hollow hub coaxially with the spool.
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Abstract
A measuring tape is contained in a housing which includes an electric motor for rotating the spool on which the tape is wound to wind the tape up. A safety mechanism is provided to switch the motor off when the tape is fully wound, and a reduction mechanism is provided between the motor and the spool, so that the spool can rotate more slowly than the motor. The instrument is portable and has a handle with which an operating switch may be associated. The motor may be battery driven.
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Citations
15 Claims
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1. A length measuring instrument comprising:
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a housing; a spool mounted for rotation in the housing; a measuring tape mounted on the spool; an electrical motor for rotating the spool to wind the tape thereon; and a reduction mechanism between the motor and the spool; said instrument characterised in that the housing provides a nonrotatable hollow hub and the motor and reduction mechanism are disposed within the hollow hub coaxially with the spool. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A length measuring instrument comprising:
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a housing; a spool mounted for rotation in the housing; a measuring tape wound on the spool; an electric motor for rotating the spool to wind the tape thereon; a two-stage epicyclic gear reduction mechanism between the motor and the spool with each of the stages thereof comprising a sun wheel, a ring gear and satellite pinion gears mounted by a drive cage and engaging the sun wheel and the ring gear; the sun wheel of a first gear stage being mounted on the motor output shaft and the ring gear being formed on a wall of the housing, force being transferred to the second gear stage via the drive cage of the first stage; means for supplying electricity to the motor; a device on the spool for attaching the end of the tape thereto; and a safety device for switching off the motor when the tape has been completely wound up, the means for supplying electricity, the reduction mechanism and the motor all being contained in sealed compartments. - View Dependent Claims (12, 13, 14, 15)
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Specification