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:
Apr. 16, 1991
Filed:
Dec. 18, 1989
William B Scobie, Houston, TX (US);
Robert A Frenzel, Waller, TX (US);
Keystone International Holdings Corp., Houston, TX (US);
Abstract
A rotary actuator comprising a housing which defines an arcuate chamber, the housing including a first monolithic portion in which the arcuate chamber is completely contained, a piston disposed in the housing for reciprocable movement in the arcuate chamber, a shaft journaled in the housing and connected to the piston and being rotated in response to movement of the piston, a floating seal assembly carried by one of the piston or the housing for effecting sealing between the piston and the housing, a fluid pressure port to introduce fluid into the housing to effect movement of the piston in the first direction and a means such as fluid pressure or a spring return to effect movement of the piston in an opposite second direction, the actuator in one preferred embodiment employing a spring return which provides a substantially constant torque acting upon the shaft as the spring moves from a compressed first position to an uncompressed second position such that the torque acting upon the shaft in both rotational directions is substantially constant.