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:
Dec. 30, 1986
Filed:
Mar. 10, 1986
Richard E Eckman, Houston, TX (US);
Dresser Industries, Inc., Dallas, TX (US);
Abstract
A power drive screwdriver that is constructed to automatically stop when a predetermined torque is reached. The screwdriver includes a housing having a pneumatically driven motor therein and an output shaft that is linked to the screwdriver bit through a releasable clutch. A control valve is positioned in the housing to control air flow to the motor. The position of the valve is controlled by a rod that extends through the shaft. A transverse slot extends through the shaft intersecting the bore therein and the transverse slot contains a pair of balls that are retained within the slot by a sleeve encircling the exterior of the shaft. Further, a reset member engages the screwdriver bit and also engages the balls to displace the balls in the slot in a direction to open the valve. When the predetermined torque is encountered, the sleeve moves upwardly, permitting the balls to separate and thereby letting the valve rod move to permit the valve to close.