Patents by Inventor Sotaro Tanaka
Sotaro Tanaka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6502499Abstract: A hydraulic recovery system for a construction machine comprises a recovery valve for supplying at least a part of a hydraulic fluid from a rod-side line, through which the hydraulic fluid is drained from a rod-side hydraulic chamber of an arm hydraulic cylinder, to a bottom-side line through a variable throttle, and a throttle valve for returning the remaining part of the hydraulic fluid, which is not recovered, from the rod-side line to a hydraulic reservoir through a variable throttle. Opening areas of those variable throttles are controlled depending on an arm flow rate supplied from hydraulic pumps to the arm hydraulic cylinder.Type: GrantFiled: September 26, 2001Date of Patent: January 7, 2003Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Naoto Sannomiya, Sotaro Tanaka
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Publication number: 20020108486Abstract: A hydraulic recovery system for a construction machine comprises a recovery valve for supplying at least a part of a hydraulic fluid from a rod-side line, through which the hydraulic fluid is drained from a rod-side hydraulic chamber of an arm hydraulic cylinder, to a bottom-side line through a variable throttle, and a throttle valve for returning the remaining part of the hydraulic fluid, which is not recovered, from the rod-side line to a hydraulic reservoir through a variable throttle. Opening areas of those variable throttles are controlled depending on an arm flow rate supplied from hydraulic pumps to the arm hydraulic cylinder.Type: ApplicationFiled: September 26, 2001Publication date: August 15, 2002Inventors: Naoto Sannomiya, Sotaro Tanaka
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Patent number: 6244048Abstract: A hydraulic drive system for a supersized hydraulic working machine such as a hydraulic excavator includes hydraulic pumps connected to main lines through a delivery line and a supply line. Branch portions from the main line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic pumps toward hydraulic cylinders. A hydraulic reservoir is connected to the main lines through a reservoir line and a drain line. Other branch portions for the drain line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic cylinders toward the hydraulic reservoir. A line branched for the delivery line includes a bypass valve for supplying the hydraulic fluid delivered from the hydraulic pumps to the supply line at a desired flow rate and returning the remaining hydraulic fluid to the hydraulic reservoir.Type: GrantFiled: January 23, 1998Date of Patent: June 12, 2001Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Sotaro Tanaka, Gen Yasuda, Masami Ochiai, Yusaku Nozawa, Hideyo Kato
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Patent number: 5839397Abstract: First cooling air (50) enters an engine room (1) through a cooling air inlet port (7a) from the exterior of the engine room (1), and is throttled by a suction tube (8a) after passing heat exchangers such as an intercooler (6a), an oil cooler (6b) and a radiator (6c), followed by entering a centrifugal fan (4). The first cooling air (50) is then blown off toward an outer circumference of the centrifugal fan (4). Second cooling air enters the engine room (1) through cooling air inlet ports (7b, 7b) from the exterior of the engine room (1), and flows around an engine (5), various electric equipments such as an alternator (10), and an oil pan (14) while cooling them. The second cooling air is then throttled by a suction tube (8b) before entering the centrifugal fan (4), and blown off toward the outer circumference of the centrifugal fan (4). Two streams of the first and second cooling air (50, 51) are discharged to the exterior through an exhaust port (9).Type: GrantFiled: June 17, 1997Date of Patent: November 24, 1998Assignee: Hitachi Construction Machinery Co. Ltd.Inventors: Shigehisa Funabashi, Yoshihiro Takada, Masatoshi Watanabe, Shinichi Shimode, Yoshio Tanito, Sotaro Tanaka, Zenji Kaneko, Ichiro Hirami, Toshio Takishita, Shinichi Mihara
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Patent number: 4571941Abstract: A hydraulic power system having a variable displacement hydraulic pump, a hydraulic motor driven by the hydraulic pump for actuating a load, with the pump and motor being connected to constitute a closed hydraulic circuit. A hydraulic servo controls the displacement volume of the pump, and a motor stop arrangement prevents, in its operative position, the motor from rotating. The system includes a control valve responsive to a main line pressure in the closed hydraulic circuit for controlling a hydraulic fluid supply to the hydraulic servo to prevent the main line pressure from substantially exceeding a predetermined level, and a control is responsive to the operation of the hydraulic servo for releasing the motor stop arrangement from the operative position when the hydraulic servo is operating.Type: GrantFiled: December 22, 1981Date of Patent: February 25, 1986Assignee: Hitachi Construction Machinery Co, Ltd.Inventors: Yukio Aoyagi, Eiki Izumi, Sotaro Tanaka, Takeshi Yamaguchi
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Patent number: 4561250Abstract: A hydraulic drive system including at least one hydraulic actuator, two variable displacement hydraulic pumps each connected to the hydraulic actuator to form a closed circuit therewith and connected in parallel with each other, two prime movers each driving one of the hydraulic pumps, and directional control valves each arranged between the hydraulic actuators and one of the hydraulic pumps. The directional control valves are each operative to shut, when one of the prime movers associated therewith is shut down, the hydraulic pump connected to the shutdown prime mover off the other hydraulic pump and the hydraulic actuator, to thereby prevent the hydraulic pump from being rotated by the pressure fluid delivered by the other hydraulic pump.Type: GrantFiled: February 5, 1982Date of Patent: December 31, 1985Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Yukio Aoyagi, Eiki Izumi, Takeshi Yamaguchi, Sotaro Tanaka
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Patent number: 4534268Abstract: A hydraulic fluid circuit of a hydraulic shovel including a first directional control valve group connected to a first hydraulic pump and including a first directional control valve and a second directional control valve respectively connected to a first hydraulic cylinder and a second hydraulic cylinder. A second directional control valve group, connected to a second hydraulic pump, includes a third directional control valve having a first working port connected to one cylinder chamber of the first hydraulic cylinder and a second working port connected to one cylinder chamber of the second hydraulic cylinder.Type: GrantFiled: July 9, 1982Date of Patent: August 13, 1985Assignee: Hitachi Construction Machinery Co., Ltd.Inventors: Takashi Yagyu, Takeshi Yamaguchi, Sotaro Tanaka, Yasuo Sakaki
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Patent number: 4504185Abstract: A hydraulic circuit for a hydraulic power shovel of the type having a swingable boom, swingable arm and a bucket attached to the end of the arm. The hydraulic circuit includes a levelling cylinder adapted to extend and contract in response to the swinging of the arm, and a switching valve device movable between a first position where it provides a communication between the levelling cylinder and a boom cylinder and a second position where it provides a communication between the levelling cylinder and an arm cylinder. When the switching valve device takes the first position, the levelling cylinder is communicated with the boom cylinder so that the boom is swung downwardly in response to the upward swinging of the arm, thereby to move the bucket horizontally. On the other hand, when the switching valve device takes the second position, the levelling cylinder and the boom cylinder are disconnected hydraulically so that the arm is allowed to swing independently of the boom.Type: GrantFiled: August 12, 1982Date of Patent: March 12, 1985Assignee: Hitachi Construction Machinery Co., Inc.Inventors: Takashi Yagyu, Takeshi Yamaguchi, Sotaro Tanaka, Yasuo Sakaki