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:
Mar. 22, 1994
Filed:
Oct. 05, 1992
Shuji Hori, Kawasaki, JP;
Kabushiki Kaisha Komatsu Seidakusho, Tokyo, JP;
Abstract
A highly reliable pilot valve apparatus controls the direction of the operation of an actuator by pivoting a lever (15) back and forth and to the right and left. A valve body (1) has a directional control spool (27) which shifts between a first position wherein it ensures that a pair of outlet ports (3.sub.3, 3.sub.4) communicate with a pair of main outlet ports (38, 39) in a forward direction and a second position wherein it ensures that the pair of outlet ports communicate with the pair of main outlet ports in a rearward direction. The directional control spool (27) is changed over between the first and second positions by an oil from another pair of outlet ports (3.sub.1, 3.sub.2). Alternatively, the valve body (1) can contain a pressure detecting directional control valve (61) such that in a first position a pressure sensing port (60) is connected to the inlet port (52) and in a second position the pressure sensing port (60) is disconnected from the inlet port ( 52). The pressure detecting directional control valve (61) contain a first spool (64) and a second spool (65) positioned in a sleeve (63) so that a first pressure receiving chamber (69) is between the first and second spools and a second pressure receiving chamber (70) is at the end of the second spool (65) which is remote from the first spool (64). Each of the first and second pressure receiving chambers (69, 70) is connected to a respective one of the outlet ports (53, 53). A spring (68) biases the first and second spools (64, 65) toward the position disconnecting the pressure sensing port (60) to the inlet port (52).