The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 23, 1977
Filed:
Oct. 06, 1975
Edmund C Dudek, St. Charles, IL (US);
Thor Power Tool Company, Aurora, IL (US);
Abstract
A pneumatic power tool having a torque sensing control system is disclosed which is capable of consistently applying a precise torque to a fastener so that uniform tightening of any number of fasteners can be obtained. A torsional strain responsive transducer is mounted internally in the tool body and includes a strain gauge network mounted on a torsionally resilient portion of one of the gear cases of the drive train of the tool, the gear case being subject to a reaction component of the torque being transmitted through the drive train. The strain gauge network provides a control signal which effects energization of a solenoid-actuated air shut-off valve in the handle of the tool to automatically terminate the operation of the tool when a predetermined torque is obtained at the output spindle. The control system permits adjustment of the torque output of the tool and provides a visual readout of such output. Because of its fast action, the solenoid-actuated shut-off valve substantially eliminates reaction torque at the handle of the tool and the components thereof are compactly arranged. The sound level of the exhaust air from the pneumatic motor is attenuated by a tortuous flow path through the interior of the tool, and the electrical conductors for the strain gauge network are also routed through the interior of the tool. Consequently, the exterior of the tool is clean. The portion of the housing of the tool that surrounds the transducer is in two parts so that certain of the components of the tool may be assembled without relative rotational movement. The two-piece housing also facilitates access to the transducer and other parts of the tool without disassembling the same.