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:
Feb. 23, 1982
Filed:
Oct. 25, 1979
Derek Brown, Eighton Bank, Gateshead, Tyne & Wear, GB;
Other;
Abstract
Control apparatus for a drive transmission such as the hydraulic drive transmission of a fork lift truck is provided in which an electrical signal is developed having a frequency representative of the rate of rotation of the drive shaft of the transmission. A first switching circuit is controlled in response to the said signal so as to remain in one state thereof during each cycle of the said signal when the duration of the cycle is less than a predetermined duration, and to be settable in another state thereof by actuation of a manually operable direction switch, serving as a forward-reverse drive selector lever, when the duration of the said cycle is greater than the said predetermined duration. A second switching circuit is so controlled in response to the said signal as to be set into one state thereof in response to a cycle of the said signal when the duration of the said cycle falls below a second predetermined duration, and to be set into another state thereof when the duration of the said cycle increases to exceed a third predetermined duration. The second switching circuit effects energization of a low gear ratio electrical actuator or a high gear ratio electrical actuator respectively depending upon which one of the said two states of the second switching means prevails.