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. 26, 1978
Filed:
Apr. 21, 1977
Kiyohumi Mizuno, Nagoya, JP;
Hiroaki Maeda, Toyota, JP;
Shigeo Takahashi, Chiryu, JP;
Tsukasa Watanabe, Toyota, JP;
Aisin Seiki Kabushiki Kaisha, Aichi, JP;
Abstract
In a hydromechanical transmission, low and high range clutches are selectively operated in response to variation of an actual speed ratio between an input shaft and an output shaft to complete low or high speed drive power train. The transmission comprises a speed ratio detecting valve for detecting lower and higher limits of a predetermined speed ratio and a clutch control valve for selectively operating the low and high range clutches when the actual speed ratio reaches in a range defined by the lower and higher limits of the predetermined speed ratio. The operation of the clutch control valve is controlled by a pressure control valve in accordance with a difference in value between a first signal responsive to a throttle opening angle and a second signal responsive to the rotation speed of the input shaft such that the low and high range clutches are selectively operated only when the difference between the first and second signals becomes a predetermined value.