Port Controls Separate Motor For Intermediate Pilot Valve Patents (Class 91/291)
  • Patent number: 11103986
    Abstract: A pneumatic nail gun comprises a working piston connected to a driving ram that is configured to drive in a fastening means and is pressurized by air when a driving process is initiated. A hand-operated trigger and a contact sensor. Simultaneous actuation of the hand-operated trigger and contact sensor activates a first control valve and initiates the driving process if the pressure in a safety control chamber is above a given pressure threshold. A second control valve is configured to be activated upon actuation of the trigger. The safety control chamber is continuously de-aerated via a throttle and is separated from a pressurized casing interior when the second control valve is activated.
    Type: Grant
    Filed: May 15, 2017
    Date of Patent: August 31, 2021
    Assignee: Joh. Friedrich Behrens AG
    Inventor: Joachim Bauer
  • Patent number: 9074612
    Abstract: A fluid operated actuator (100) is provided. The fluid operated actuator (100) includes a cylinder body (101) and a piston (102) movable within the cylinder body (101). The piston (102) defines a first chamber (105) and a second chamber (106). The fluid operated actuator (100) can include a fluid inlet (107) formed in the first chamber (105). A bleed port (110) can be formed to provide fluid communication between the first chamber (105) and the second chamber (106).
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: July 7, 2015
    Assignee: Norgren GmbH
    Inventor: Roger Studer
  • Patent number: 7464493
    Abstract: A work machine is provided having a starter motor for starting a prime mover, which without provision of any special hydraulic equipment, allows for draining pressure oil that still remains in a hydraulic actuator for driving a front attachment. The work machine is provided with a boom cylinder for driving a front attachment, a flow rate control valve for controlling a flow of pressure oil to be supplied to the boom cylinder, and a pilot valve for producing an output of a pilot control signal, which serves to switch the flow rate control valve, by using, as a primary pressure, pressure oil delivered from a pilot hydraulic pump driven by an engine. A fuel stop switch is provided for performing stop control on a supply of fuel, which drives the engine, and a switch is provided for maintaining drivable a starter motor, which starts the engine, responsive to the stop control of the supply of fuel to the engine by the fuel stop switch.
    Type: Grant
    Filed: September 8, 2005
    Date of Patent: December 16, 2008
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kouji Ishikawa, Tadatoshi Shimamura, Hidetoshi Satake, Nobuei Ariga
  • Patent number: 5297469
    Abstract: An improved fluid power actuator assembly comprising a power piston reciprocatingly mounted in a cylinder bore which is formed in a compact fluid power manifold providing the necessary circuit connections between control valves mounted on the housing and the cylinder bore. The cylinder bore preferably includes two circumferentially spaced signal ports disposed in the wall of the cylinder bore along the path of travel of the piston in addition to the primary power ports located at each end of the cylinder bore to drive the piston. The piston includes at least one circumferential groove and functions as a spool valve for opening and closing communication between the signal ports as the piston travels in the cylinder. Appropriate control valves and signal pressure communicating with the signal ports is disclosed to enable a fluid power signal to be generated which is related to the position of the piston during its travel in the cylinder bore.
    Type: Grant
    Filed: February 23, 1993
    Date of Patent: March 29, 1994
    Inventor: Robert E. Raymond
  • Patent number: 5237906
    Abstract: An improved fluid power actuator assembly comprising a power piston reciprocatingly mounted in a cylinder bore which is formed in a compact fluid power manifold providing the necessary circuit connections between control valves mounted on the housing and the cylinder bore. The cylinder bore includes at least two circumferentially spaced signal ports disposed in the wall of the cylinder bore along the path of travel of the piston in addition to the primary power ports located at each end of the cylinder bore to drive the piston. The piston includes at least one circumferential groove and functions as a spool valve for opening and closing communication between the signal ports as the piston travels in the cylinder. Appropriate control valves and signal pressure communicating with the signal ports is disclosed to enable a fluid power signal to be generated which is related to the position of the piston during its travel in the cylinder bore.
    Type: Grant
    Filed: October 25, 1991
    Date of Patent: August 24, 1993
    Inventor: Robert E. Raymond
  • Patent number: 5049038
    Abstract: A two stage fluid compressor is operated by a pneumatically operated relay valve controlled by a fluidic switching device in which switching pulses of pressurized control air are obtained automatically on movement of a compression piston in one of the compression stages.
    Type: Grant
    Filed: October 10, 1990
    Date of Patent: September 17, 1991
    Assignee: Normalair-Garrett (Holdings) Ltd.
    Inventor: Robin H. J. Searle
  • Patent number: 4870891
    Abstract: A double acting piston and cylinder air motor with pneumatically actuated pilot valves for shifting a directional control valve, where the pilot valves are controlled by pilot ports in the cylinder as they are uncovered by the piston.
    Type: Grant
    Filed: March 13, 1989
    Date of Patent: October 3, 1989
    Assignee: Stewart Warner Corporation
    Inventors: Jerry D. Shew, Stuart A. Evans
  • Patent number: 4819542
    Abstract: A percussive tool comprising a housing (1) accommodating a movable striker (2) and connected with a power cylinder (6) in which is arranged a striker shank (4) with a gripping mechanism (14) and a drive in the form of a hydraulic cylinder (8). The percussive tool is provided with a control unit having a spool valve means (18) to control a distribution means (19). The spool valve means (18) has a casing (22) and a spool (23) taking two positions in the casing and defining two chambers (25, 26) interconnected through a throttling means (24). One chamber (25) constantly communicates with a discharge line (21), and the other chamber (26) is periodically put in communication with the space of the hydraulic cylinder (8). The spool (23) is spring-loaded with respect to the casing (22) on the side of one chamber (25) and takes in this case its first position.
    Type: Grant
    Filed: August 21, 1987
    Date of Patent: April 11, 1989
    Assignee: Spetsialnoe Konstruktorskoe Bjuro Gidroimpulsnoi Tekhniki Sibirskogo Otdelenia Akademii Nauk SSSR
    Inventors: Petr Y. Fadeev, Vladimir Y. Fadeev, Vladeen V. Korobkov, Rim A. Kulagin, Nikolai P. Ermilov
  • Patent number: 4756230
    Abstract: A reciprocating piston and cylinder pneumatic motor with a sound-reducing system that diffuses exhausting air by directing it across the curved outer surface of the cylinder.
    Type: Grant
    Filed: December 19, 1986
    Date of Patent: July 12, 1988
    Assignee: Stewart Warner Corporation
    Inventor: Jerry D. Shew
  • Patent number: 4632013
    Abstract: A reciprocating piston fluid powered motor having fluid inlet and outlet, wherein reciprocation is controlled by a reciprocable valve spool carrying a manifold communicating with said fluid inlet and outlet and cooperating with a valve slide shiftable on said valve spool to control reciprocation of said valve spool.
    Type: Grant
    Filed: June 21, 1984
    Date of Patent: December 30, 1986
    Assignee: Sprague Devices, Inc.
    Inventors: Richard Frigon, Alan K. Forsythe
  • Patent number: 4419055
    Abstract: A fluid supply system includes a pump body having a main bore connectible through inlet check valves to draw fluid from a fluid reservoir and through outlet check valves to supply low pressure fluid to a low pressure function upon reciprocation of a free piston in the main bore. The free piston includes a pair of coaxial driving pistons on either side which extend into main passages which are alternately connected to a high pressure source to cause reciprocation of the free piston. A first spool valve which responds to the completion of a free piston stroke activates a second spool valve which changes the high pressure source connections to the driving pistons.
    Type: Grant
    Filed: September 26, 1980
    Date of Patent: December 6, 1983
    Assignee: Deere & Company
    Inventor: Ronnie F. Burk
  • Patent number: 4314612
    Abstract: A hydraulically operated impact tool is provided for performing land-based or undersea tasks including hammering, chipping, scraping, punching, and cutting. The tool's features include a spring (preferably hydroelastic) for storing impact-stroke energy, a configuration of valves which eliminates flow in the supply and return lines during the impact stroke, and a control approach which provides operator selection of either single-blow or continuous-cycling operation.
    Type: Grant
    Filed: July 20, 1978
    Date of Patent: February 9, 1982
    Assignee: Battelle Development Corporation
    Inventors: David L. Thomas, Donald J. Hackman
  • Patent number: 4241641
    Abstract: A pilot assembly for switching the fluid supply valve of a hydraulic pump is actuated by the pressurized hydraulic fluid which operates the hydraulic pump. The hydraulic pump includes a main cylinder, a main piston within the main cylinder, and a main valve for supplying pressurized hydraulic fluid to the rear end of the main cylinder for driving the piston forwardly. The pilot assembly includes a pilot cylinder and a pilot spool within the cylinder. A first hydraulic conduit connects one end of the pilot cylinder to the front end of the main cylinder, and a second hydraulic conduit connects the other end of the pilot cylinder to the main cylinder at a position spaced rearwardly from the front end of the main cylinder. When the main piston passes forwardly of the second hydraulic conduit, the pressurized hydraulic fluid in the main cylinder moves the pilot spool, and pressurized hydraulic fluid is allowed to flow to the main valve to switch the main valve.
    Type: Grant
    Filed: August 14, 1978
    Date of Patent: December 30, 1980
    Inventor: Gerald H. Reinert
  • Patent number: 4052107
    Abstract: The disclosure concerns a hydraulically driven impactor in which the operng cycle of a reciprocating piston is determined by the retraction velocity and displacement of the piston itself. Energy is conserved and heat dissipation minimised by the utilization of hydraulic spring accumulators to decelerate the piston. The drive to the piston is switched into a forward direction at such a point in each displacement cycle that the rebound energy of the piston is always re-absorbed into the drive fluid. The impactor operates at optimum acceleration and frequency at all times, whether or not impact occurs, and this feature combined with high energy conservation makes the impactor particularly suitable for use in a full-face tunnelling machine where high power density is required and individual impactors are often constrained to operate without impacting the rock face for considerable periods.
    Type: Grant
    Filed: April 7, 1976
    Date of Patent: October 4, 1977
    Assignee: The Secretary of State for Industry in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventor: Andrew George Hay
  • Patent number: 4026193
    Abstract: A hydraulic pile driving hammer system is described which requires only a single pressure operated pilot to obtain switching for reversal of hydraulic forces at both ends of its stroke.
    Type: Grant
    Filed: September 19, 1974
    Date of Patent: May 31, 1977
    Assignee: Raymond International Inc.
    Inventor: Peter B. Olmsted
  • Patent number: 4020746
    Abstract: A hydraulically operable linear motor with a double-acting reciprocable piston in a cylinder, in which one side of the piston has connected thereto a piston rod so as to form with this one side an annular piston surface which is continuously exposed to a desired working pressure. The other side of the piston is by means of a hydraulically actuated control valve alternately exposed to the working pressure and to the pressure in an exhaust conduit. The pressure for actuating the valve spool of the control valve is generated in a conduit section which communicates with two annular grooves in the two cylinder sections separated from each other by the piston and adapted alternately to be closed off from the above mentioned conduit section. This conduit section communicates through throttles with the exhaust conduit.
    Type: Grant
    Filed: December 3, 1975
    Date of Patent: May 3, 1977
    Assignee: Fried. Krupp Gesellschaft mit beschrankter Haftung
    Inventor: Friedrich Karl Arndt
  • Patent number: 3995700
    Abstract: In a hydraulic percussion rock drill the operation of the working fluid distributing valve is controlled to effect a variation in percussive blow energy and blow frequency by varying the piston hammer stroke. Actuation of the distributing valve is controlled by a remote controlled hydraulically actuated pressure control valve interposed in a fluid passage which conducts hydraulic fluid from the hammer bore to actuate the distributing valve. Substantially infinite variation of hammer impact blow energy between high and low limits provides for selecting the maximum penetration rate of the drill for any type of rock conditions. The hydraulic rock drill is connected to a source of hydraulic fluid supplied to the drill at substantially constant fluid power by a variable displacement constant power hydraulic pump.
    Type: Grant
    Filed: October 14, 1975
    Date of Patent: December 7, 1976
    Assignee: Gardner-Denver Company
    Inventors: James R. Mayer, Dieter K. Palauro