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:
May. 01, 2012
Filed:
Oct. 01, 2007
Markus Herrmann, Scheidegg, DE;
Thomas John, Sulzheim, DE;
Markus Herrmann, Scheidegg, DE;
Thomas John, Sulzheim, DE;
ZF Friedrichshafen AG, Friedrichshafen, DE;
Abstract
A pressure medium-actuated control device of an automated step-by-step variable speed transmission. The device having a control valve for controlling an actively engaged disconnectable type clutch which is disposed along a power flow path between a motor and a transmission input shaft, and a self-retaining valve located in the pressure supply of the clutch control valve for a rotational speed-dependent emergency actuation of the disconnectable type clutch. An electrical switch-off actuator is connected to the self-retaining valve such that the valve piston, of the self-retaining valve, can be moved into an idle position to lock the pressure supply of the clutch control valve in a powered state of the switch-off actuator, and into an operating position determined by the applied control pressures in the power-off state of the switch-off actuator.