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公开(公告)号：JPH0565903A
公开(公告)日：1993-03-19
申请号：JP22434391
申请日：1991-09-04
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI , TATEKAWA NOBORU , OKAJIMA SUSUMU , ARITAKE TAKESHI
Abstract: PURPOSE:To provide an attachment hydraulic circuit enabling the gentle start of a working device so as to attain the safety of work and prolong the life span of the whole device. CONSTITUTION:There are provided a direction switching valve 12 for operating the start and stop of a working device 1, and a flow control valve 31 for controlling the flow of pressure oil supplied to the working device 1. There is also provided an escape valve 32 operated in response to differential pressure between load pressure at the inlet of the working device 1 and the delivery pressure of pressure oil from a hydraulic source 21 so as to let pressure oil from a hydraulic pump 21 escape to a return circuit 3B in order to maintain the differential pressure to the specified value. There are further provided a pressure transmission delay means 37a, installed at pilot circuits 33, 34, 35 for leading load pressure at the inlet of the working device 1, for limiting the transmission of this load pressure so as to delay the response of the escape valve 32; and a pressure control valve for regulating the maximum pressure of the pilot circuits 33, 34.
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公开(公告)号：JPS5877965A
公开(公告)日：1983-05-11
申请号：JP17577381
申请日：1981-11-04
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KUBODERA KEIZOU , KOMURA TOSHIO , OKAJIMA SUSUMU , MIYAZAKI RIYOUJI
IPC: F16C35/077 , F16H55/36
Abstract: PURPOSE:To lessen a press-fit margin of a metallic ring for a fitting hole by receiving an axial load working on the metallic ring with a projection provided at the center of a synthetic resin sheave. CONSTITUTION:Two parts 13a and 13b of a metallic ring 13 are forced into fitting holes 11 formed in the center of a synthetic resin sheave body 10 until a cut groove 15 contacts a first projection axially from both sides. Even when an axial load works on the metal ring 13, for example, by lateral pulling of a rope, it is received by a counting force of the metallic ring 13 forced into the fitting holes formed in the synthetic resin sheave body 10. This can prevent the metallic ring 13 from slipping off the body 10 while lessening the press-fit margin of the metallic ring for the fitting holes.
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公开(公告)号：JPH05179820A
公开(公告)日：1993-07-20
申请号：JP35822291
申请日：1991-12-27
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： ARITAKE TAKESHI , TATEKAWA NOBORU , OKAJIMA SUSUMU , KANAI TAKASHI
Abstract: PURPOSE:To prevent dust resulting from crushing from being spattered and reflected onto a water spraying side when concrete, etc., are crushed by a hydraulic breaking machine. CONSTITUTION:A cross water passing pipe 20 in which a water passage is provided is installed fixedly at the rear of a supporting bracket 14 on which crushing teeth 11, 11 are mounted. Four top ends 20a to 20d of the water passing pipe 20 are projected outward from the supporting bracket 14 and, on the outside of the crushing teeth 11, water spraying nozzles 21a to 21d for forming water curtain in the extending direction of the top ends are provided. The nozzles 21a and 21c forms the water curtain spread in horizontal direction and those 21b and 21d forms it spread in vertical direction. By this, the area crushed by the crushing teeth 11, 11 is almost covered by the water curtain from the rear position to prevent dust from coming out of the water curtain.
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公开(公告)号：JPH04366002A
公开(公告)日：1992-12-17
申请号：JP16621391
申请日：1991-06-12
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI , TATEKAWA NOBORU , OKAJIMA SUSUMU , ARITAKE TAKESHI
Abstract: PURPOSE:To provide a hydraulic circuit with which an energy loss of a hydraulic pressure source to drive a hydraulic pressure actuator for attachment can be reduced, and the capacity of the hydraulic actuator for attachement can be fully displayed. CONSTITUTION:This hydraulic circuit is provided with a hydraulic actuator 5 for an attachment driven by a pressurized oil from a hydraulic power source and a flow control valve 7 for controlling flow of pressurized oil to be supplied to the hydraulic actuator 5. Also a relief valve 10 to drain pressurized oil above the flow control valve 7 into a tank side when a pump discharge pressure becomes higher by a specified value than a load pressure below the flow control valve 7, and a pressure regulating valve 15 to limit the maximum pressure of the load pressure are provided.
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