Working Member Position Control Of Motive Fluid And Locking Means Patents (Class 91/43)
  • Patent number: 11512665
    Abstract: Locking linear actuators, thrust reversers for aircraft that include the locking linear actuators, and methods of manufacturing the locking linear actuators. The disclosed locking linear actuators include an actuator housing that defines a bore housing an actuator piston and a lock sleeve. A portion of the actuator piston defines a lock aperture, housing a locking tab capable of radial movement. When the actuator is retracted, the locking tab engages with a step in the surface of the bore to lock the linear actuator, a distal portion of the lock sleeve extends into a portion of the actuator piston to prevent the locking tab from disengaging from the step in the surface of the bore.
    Type: Grant
    Filed: March 20, 2020
    Date of Patent: November 29, 2022
    Assignee: The Boeing Company
    Inventor: Sam Miao
  • Patent number: 11111932
    Abstract: A modular fluid actuator system is provided for generating a relative motion between a first fluid transfer chamber of a first module unit and a piston rod arrangement in an axial direction. The modular fluid actuator system comprises a fluid supply, a valve device coupled to the fluid supply and to the first fluid transfer chamber, a control unit coupled to the valve device for controlling the relative motion between the first fluid transfer chamber and the piston rod arrangement, the first fluid transfer chamber is coupled to a first sleeve portion exhibiting a first expandable hollow space arranged for fluid communication with the valve device via the first fluid transfer chamber.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: September 7, 2021
    Assignee: SAAB AB
    Inventor: Magnus Landberg
  • Patent number: 10626824
    Abstract: A thrust reverser includes: a thrust-reversing element movable between a stowed position and a deployed position; at least one hydraulic actuator operably coupled to move the thrust-reversing element between the stowed and deployed positions; at least one hydraulic primary lock configured to transition, in response to a first activation pressure, between an engaged state, where movement of the thrust-reversing element is inhibited, and a released state, where movement of the thrust-reversing element is uninhibited; and a directional control unit fluidly coupled to the hydraulic actuator and the hydraulic primary lock, the directional control unit configured to transition from a first stage to a second stage in response to a second activation pressure that is greater than the first activation pressure, and where a transition from the first stage to the second stage by the directional control unit causes the hydraulic actuator to move the thrust-reversing element to the deployed position.
    Type: Grant
    Filed: March 19, 2018
    Date of Patent: April 21, 2020
    Assignee: Woodward, Inc.
    Inventors: Joseph Thomas Kopecek, Julian Sweet
  • Patent number: 9458865
    Abstract: A first piston (10) is inserted in a housing (2) so as to be hermetically movable vertically. A second piston (20) is inserted in a cylindrical hole (14) of the first piston (10) so as to be hermetically movable axially, and has an output rod (26) projecting upward from the housing (2). A lock chamber (40) is formed below the first piston (10) and the second piston (20), and a release chamber (42) is formed above the first piston (10) and the second piston (20). A force multiplier (52) is arranged in the housing (2) so as to cause (i) a first force, with which a pressurized fluid supplied into the lock chamber (40) pushes the first piston (10) upward, to be transformed in a force-multiplying manner into a second force and (ii) the second force to be transmitted to the second piston (20). Further, a change-over mechanism (54) is arranged in the housing (2) so as to selectively couple the first piston (10) to the housing (2) or the second piston (20).
    Type: Grant
    Filed: May 16, 2012
    Date of Patent: October 4, 2016
    Assignee: KOSMEK LTD.
    Inventors: Hideaki Yokota, Keitaro Yonezawa
  • Publication number: 20140208933
    Abstract: The present invention relates to a bicycle seat post structure, and more particularly, to a structure provided with a hydraulic actuator within which is configured with an upper oil compartment, an intermediate oil compartment, and a lower oil compartment; the three oil compartments intercommunicate. It is characterized in that the bicycle seat post structure provides an upper valve moving simultaneously with the pin and configured between the upper oil compartment and the intermediate oil compartment; the upper valve will be closed to disconnect the upper oil compartment from the intermediate oil compartment when the pin is in a state of locking. Thus, the valve will stop moving up because it is positioned above the upper and the intermediate oil compartments and consequently controlled by the oil within the compartments, so as to stop the seat sliding upward and further to be combined with the bicycle frame as a whole.
    Type: Application
    Filed: January 30, 2013
    Publication date: July 31, 2014
    Inventor: Frank Kuo
  • Patent number: 8596608
    Abstract: A sub sea valve actuator system including a piston and cylinder assembly and a return spring arranged in an actuator housing, a hydraulic pump and electric motor assembly associated with the piston and cylinder assembly, and hydraulic flow lines for hydraulic medium driving the piston and cylinder in relative displacement against a force of the return spring. The valve actuator system includes a detector configured to detect an end-of-stroke position of the piston and cylinder assembly. The detector includes at least one of: a motor current monitoring circuit unit, a hydraulic medium pressure sensor unit, a position sensor unit, and a linear variable differential transformer unit. An electromechanical arresting mechanism is arranged to be energized for releasably arresting the return spring in a compressed state in result of the detected end-of-stroke position.
    Type: Grant
    Filed: May 12, 2009
    Date of Patent: December 3, 2013
    Assignee: Veteo Gray Scandinavia AS
    Inventors: Tom Grimseth, Christian Borchgrevink, Jon Flidh, Jan Olav Pettersen
  • Publication number: 20100212488
    Abstract: A cylinder having a hollow cylindrical body with an axially moveable rod disposed therein that is moveable between a rest position and a stop position. The cylindrical body and rod are configured so as to create a main chamber located between a lower surface of the rod and a base of the cylindrical body. And to also create an auxiliary chamber that is connectable to the main chamber via a flow channel in the rod. In one implementation the main chamber is adapted to contain a gaseous fluid and an oily fluid mixture when the rod is in the rest position so that the fluid exerts a first force on the lower surface of the rod to urge the rod toward the rest position. When the rod is in the stop position the main chamber predominately contains only the oily fluid.
    Type: Application
    Filed: October 6, 2008
    Publication date: August 26, 2010
    Applicant: NITRO-GAS, S.A. Unipersonal.
    Inventors: Antonio Valor Valor, Alberto Gabicagogeascoa Benito
  • Publication number: 20090194641
    Abstract: A locking mechanism, which permits fixation to a piston rod of a linear actuator relatively to a cylinder of the actuator, as well as a linear actuator equipped with such a locking mechanism as well as to an aircraft with at least one linear activator that is equipped with the locking mechanism. The locking mechanism includes a plurality of first positive locking elements which are arranged lengthwise with the outside circumference of the cylinder and in certain distances to one another and at least one second positive locking element, which is moved together with the piston rod upon activation of the linear actuator and thus passes a segment of the cylinder. The at least one second positive locking element is positively engageable with one of the plurality of first locking elements at discrete positions of the cylinder lengthwise, by which the piston rod is fixed relatively to the cylinder.
    Type: Application
    Filed: August 31, 2006
    Publication date: August 6, 2009
    Inventor: Gunnar Haase
  • Patent number: 7497523
    Abstract: A pressure locking master cylinder including a fluid reservoir for storing a hydraulic fluid, a housing, a piston slidably received within the housing and defining a working chamber and a blocking chamber, wherein the blocking chamber is in fluid communication with the reservoir, and a valve positioned between the blocking chamber and the reservoir, the valve being adapted to selectively trap the hydraulic fluid within the blocking chamber to lock the piston in a position with respect to the housing.
    Type: Grant
    Filed: March 8, 2005
    Date of Patent: March 3, 2009
    Assignee: Delphi Technologies, Inc.
    Inventors: Gary C. Fulks, Douglas E. Poole, Timothy A. Haerr
  • Patent number: 7370570
    Abstract: A fluid pressure cylinder can apply a fastening force to an axially movable reciprocating rod. A reciprocating rod 13 is mounted in a case main body 10 so as to be reciprocable in a forward direction and a backward direction, and two lock units 16a and 16b are incorporated in the case main body 10, and the lock units 16a and 16b include: lock sleeves 18a and 18b mounted axially movably and having taper surfaces 22a and 22b; and retainers 19a and 19b holding steel balls 21a and 21b that are fitted in the reciprocating rod 13 axially movably and engaged with the taper surfaces. A fastening cylinder 41 that contains a fastening rod so as to be reciprocable in a fastening direction and a fastening release direction is attached to the case main body 10, a fastening surface 44 contacting with the lock sleeves 18a and 18b being formed in the fastening rod, and the reciprocating rod 13 is fastened by the two lock units 16a and 16b.
    Type: Grant
    Filed: March 9, 2005
    Date of Patent: May 13, 2008
    Assignee: Koganei Corporation
    Inventors: Akio Nakata, Masakazu Tetsuka
  • Patent number: 7299739
    Abstract: A fluid pressure cylinder has a piston rod 18 fixed to a piston 26 and projecting outside a cylinder body 23. A lock surface 43 inclining to a radial direction of the piston rod 18 is formed in an engagement member 31 provided in the piston rod 18. A lock rod 35 reciprocating in an about right-angle direction to the piston rod 18 is built into a lock cylinder 33 provided in the cylinder body 23. The lock rod 35 is provided with: a large-diameter section 35a fitted into a guide hole 36 formed in the lock cylinder 33; and a slide contact section 37 provided in the large-diameter section 35a via a constriction section 35b. The slide contact section 37 contacts with a radial-inner portion of the lock surface 43 when the lock rod 35 comes nearest to the piston rod 18.
    Type: Grant
    Filed: January 29, 2004
    Date of Patent: November 27, 2007
    Assignee: Koganei Corporation
    Inventors: Akio Nakata, Masakazu Tetsuka
  • Patent number: 6782799
    Abstract: A double-acting hydraulic actuator with an axial locking device has a cylinder chamber defined by two coaxial cylindrical walls of different diameters interconnected by a frustoconical wall. A guide piston sliding in the smaller-diameter cylindrical wall is fixed to an end of an actuator rod. The actuator rod has an annular protuberance of diameter equal to the diameter of the cylindrical wall. An annular stepped piston providing sealing between the two cylinder chambers is slidably mounted in a middle portion of the actuator rod to slide between the piston and the annular protuberance. When the actuator is extended, a narrowed end of the annular piston bears against conical surfaces of two half-rings and urges them outwards. When the half-rings are pushed outwards and the narrowed end of the annular piston becomes interposed between them and the middle portion of the actuator rod.
    Type: Grant
    Filed: December 17, 2002
    Date of Patent: August 31, 2004
    Assignee: Hydraulique Production Systems
    Inventor: Pierre Vincent
  • Patent number: 5746055
    Abstract: A hydraulic tile and trim mechanism for a marine outboard drive that provides a compact assembly and which ensures that contaminants which may enter the hydraulic fluid can accumulate in the fluid reservoir and will not be circulated by the fluid pump. This is accomplished by positioning the reservoir below the fluid pump and using a pick-up tube that does not extend into the bottom of the reservoir so that the contaminants can accumulate therein without being circulated.
    Type: Grant
    Filed: March 13, 1996
    Date of Patent: May 5, 1998
    Assignee: Sanshin Kogyo Kabushiki Kaisha
    Inventors: Daisuke Nakamura, Masahiko Iida
  • Patent number: 5727442
    Abstract: The invention relates to a safety arrangement on hydraulic piston-cylinder units. In particular for monitoring locking cylinders, e.g., of operating tools mounted on a grab bucket boom. A sensor for monitoring the piston position is provided on the piston-cylinder unit and is coupled electrically to a monitoring circuit for triggering an alarm arrangement if the piston is incorrectly positioned. The sensor (3) is coupled to an electrically actuatable locking valve (2) coupled in the monitoring circuit (9) for controlling the hydraulic piston-cylinder unit (1).
    Type: Grant
    Filed: November 2, 1995
    Date of Patent: March 17, 1998
    Assignee: Wimmer Hartstahl Ges.mbH & Co. KG
    Inventor: Alois Wimmer
  • Patent number: 5349894
    Abstract: A method for locking a hydraulic actuator in a predetermined position and a locking hydraulic actuator are provided. The method includes the steps of supplying hydraulic fluid to a forward chamber in the hydraulic actuator, transferring the hydraulic fluid from the forward chamber into a forward moiety of the rearward chamber in the hydraulic actuator, and sealing the hydraulic fluid in the forward moiety of the rearward chamber to accomplish the locking function. Conversely, the actuator lock is released by the application of fluid supply pressure to the rearward variable chamber.
    Type: Grant
    Filed: October 1, 1993
    Date of Patent: September 27, 1994
    Assignee: Loud Engineering & Manufacturing
    Inventor: Arthur O. Greer
  • Patent number: 5341722
    Abstract: A positioning apparatus can perform high-accuracy positioning in a short time without a Curvic (trademark) or positioning coupling. With provision of a hydraulic motor having a rotary shaft fixed to a turret head and a hollow type rotary encoder for detecting the angle of rotation of the rotary shaft, rotation of the hydraulic motor is controlled by a controller via a control valve. Locking of the rotary shaft is performed by a rebound force of a spring provided in a hydraulic cylinder by pressing a pad provided at a tip portion of a rod against a disk. Unlocking of the rotary shaft is performed by supplying a hydraulic fluid into a cylinder chamber by switching a directional control valve.
    Type: Grant
    Filed: August 12, 1992
    Date of Patent: August 30, 1994
    Assignee: Daikin Industries, Ltd.
    Inventors: Nobuyuki Tani, Tenzo Yamaguchi
  • Patent number: 5097748
    Abstract: A hydraulic cylinder that locks into position has a housing (1) with at least one pressure connection (7) and a piston (3) and rod (6) that travel tight in an out of the housing. The locking mechanism comprises a piston (11) that rests against a spring (35) and a barrier mechanism (23) with a cage of balls (25) that roll radially into a locking position in a locking groove (26) and back into an unlocking position in an unlocking groove (22). The primary piston communicates with a hollow space (18) and acts on a primary participating surface (19) and the locking piston communicates with an unlocking space (13) and acts on an unlocking surface (14) by way of the pressure connection. There is a variable choke (17), which disengages after a while, beween the pressure connection and the primary space (18) in the primary piston (3).
    Type: Grant
    Filed: December 20, 1990
    Date of Patent: March 24, 1992
    Assignee: Pacoma Hydraulik GmbH
    Inventors: Georg Koch, Wolfgang Traupe, Frank van de Poel, Kurt Schaible, Holger Seel
  • Patent number: 4997160
    Abstract: An ancillary hydraulic driven ball lock control valve actuation plunger cooperates with a piston for displacing a timer valve. An annular locking plunger is pressurized by fluid at a control port, the sliding motion of the plunger controlling the position of locking balls. As the locking balls change their position, they vary the radial extension of a further plunger assembly, the latter having detent means for displacing the plunger of a timer valve and thereby changing the valve's state.
    Type: Grant
    Filed: June 8, 1990
    Date of Patent: March 5, 1991
    Assignee: Grumman Aerospace Corporation
    Inventor: Joseph C. Pellegrino
  • Patent number: 4989828
    Abstract: An ancillary mechanically driven ball lock control valve actuation plunger cooperates with a piston for displacing a timer valve plunger. An annular locking plunger is pressurized by fluid at a control port, the sliding motion of the plunger controlling the position of locking balls. As the locking balls change their position, they vary the radial extension of a radial plunger. A first portion of a spring-biased cam maintaining contact with the outward end of the radial plunger. When the radial plunger moves to an extended position, it moves the cam until a second cam portion depresses a timer valve plunger thus changing the timer valve state.
    Type: Grant
    Filed: July 25, 1990
    Date of Patent: February 5, 1991
    Assignee: Grumman Aerospace Corporation
    Inventor: Joseph C. Pellegrino
  • Patent number: 4854218
    Abstract: The invention relates to a piston and cylinder unit whose piston rod is provided with a rack extending along it. The rack is in mesh with a ring of teeth (such as the teeth of a toothed belt or the teeth of a gear wheel) adapted to revolve about one axis (in the case of a gear wheel) or about at least two axes (in the case of a toothed belt). Such meshing engagement takes place in every position of the piston rod. When the piston rod is moved in the direction of its length the ring of teeth revolves about at least one axis and rotates a means for influencing the motion of the piston rod. Such means may for example be a liquid brake or a synchro transmitter connected with a NC unit controlling the supply of driving fluid to the piston and cylinder unit.
    Type: Grant
    Filed: October 1, 1986
    Date of Patent: August 8, 1989
    Inventor: Kurt Stoll
  • Patent number: 4785712
    Abstract: A hydraulic operating apparatus in which a differential piston is used as a drive unit, and in which the differential piston is driven by applying a high pressure fluid on a large piston face side through a hydraulic pressure control device for controlling the hydraulic pressure, and a high pressure fluid always being applied on the small piston face side. The hydraulic operating apparatus is constructed such that a high pressure fluid is applied concurrently on both piston faces when the differential piston stops at its receded position, and a thrust generated due to the difference between the forces applied on the both piston faces is held in check by a holding device acting on the differential piston or its extension. The differential piston is moved forward upon the removal of the holding force of the holding device, and the piston is moved backward upon the removal of the high pressure fluid on the large piston face side.
    Type: Grant
    Filed: May 27, 1986
    Date of Patent: November 22, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshiaki Yoshizumi, Tsutomu Sugiyama
  • Patent number: 4784037
    Abstract: A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing futher movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.
    Type: Grant
    Filed: December 28, 1982
    Date of Patent: November 15, 1988
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Joseph Fabyan, Carl W. Williams
  • Patent number: 4779513
    Abstract: A pneumatic cylinder device having a decleration mechanism. The pneumatic cylinder device has a pneumatic cylinder including a cylinder accomodating a piston movable in the cylinder in response to supply and discharge of compressed air and having a connected piston rod. The pneumatic cylinder further includes a position detector such as a combination of proximity switches and a magnet carried by the piston designed for producing a deceleration signal and a stopping signal when the piston rod has reached a predetermined deceleration starting position and a designated stopping position, respectively. A brake which is connected to the pneumatic cylinder is adapted for stopping the movement of the piston rod in response to the stopping signal produced by the position detector. The pneumatic cylinder device further comprises a deceleration stage connected to the brake and adapted for decelerating the piston rod in response to the deceleration signal produced by the position detector.
    Type: Grant
    Filed: March 14, 1985
    Date of Patent: October 25, 1988
    Assignee: Nippon Joucomatic Co., Ltd.
    Inventor: Takashi Kimura
  • Patent number: 4742758
    Abstract: The present invention relates to a fluid-operated actuator, constituted by a cylinder and by a double-effect piston, provided with a device suitable to automatically locking the same piston at the end of its working stroke.
    Type: Grant
    Filed: September 4, 1987
    Date of Patent: May 10, 1988
    Assignee: Alfa Romeo Auto S.p.A.
    Inventor: Francesco Della Rocca
  • Patent number: 4690033
    Abstract: A method and arrangement for reciprocating a piston in a cylinder of a fluid actuated actuator between one and another alternate positions, and using the piston fluid actuator fluid to move a lock member from a first position to a second position to lock the cylinder when it is moved from one position to its other alternate position. Actuator fluid is communicated to unlock the lock member and to move the piston back to its one position. In another form, the lock member is moved to its first position by the actuator pressure fluid which actuates a valve to communicate actuator fluid pressure from the lock member to the cylinder to move the piston back to its said other position.
    Type: Grant
    Filed: December 16, 1985
    Date of Patent: September 1, 1987
    Inventor: Denzal W. Van Winkle
  • Patent number: 4526086
    Abstract: A piston-cylinder assembly for displacing a load through a long stroke consists of a rod, a piston slidable on the rod and by fluid pressure the piston is clamped to the rod, and a cylinder in which the piston is contained. By clamping the piston to the rod and introducing fluid into the cylinder, relative movement is caused between the piston and cylinder and the rod. When one assembly is used, the movement is intermittent but, by mounting two pistons on the rod, each piston being in a separate cylinder, and by controlling the flow of fluid, the movement is continuous.
    Type: Grant
    Filed: June 16, 1982
    Date of Patent: July 2, 1985
    Assignee: Davy-Loewy Limited
    Inventors: James A. Holton, James C. Inman
  • Patent number: 4524676
    Abstract: A hydraulic cylinder having a locking device disposed in either, or both head ends which attach to the cylinder, has a piston reciprocally movable within a piston chamber formed in the cylinder. A stud member having a groove portion and a stud portion, secures to the piston for reciprocal movement therewith. The stud member axially moves within a stud bore formed in the head end such that, the stud bore acts as a variable volume stud chamber. A plunger member, disposed in the head end, is in fluid communication with the variable volume stud bore such that, movement of the stud member into the stud bore increases the fluid pressure, thus forcing the plunger out of contact with the stud portion of the stud member. When a predetermined pressure occurs, an outlet valve to the stud bore opens, reducing the fluid pressure and allowing the plunger to be urged into engagement with the groove portion of the stud member thus effecting a locked condition.
    Type: Grant
    Filed: January 19, 1984
    Date of Patent: June 25, 1985
    Assignee: American Standard Inc.
    Inventor: Larry K. Rogers
  • Patent number: 4515065
    Abstract: A high resolution servo actuator is responsive to an electronic control or manual control. An output shaft having fast response and infinite positioning for stroking a manual servo valve on a pump is rotated by hydraulic power. A set of hydraulic working cylinders and centering cylinders are connected through a rack and pinion drive to a shaft. Centering cylinders utilize stop tubes to prevent its pistons from traveling past the center position and applying a constant force to center the shaft. A directional valve controls the flow of hydraulic fluid to the working cylinders for driving the shaft throughout its range of travel. An electrohydraulic servo valve converts the electronic control signal into hydraulic flow to the actuator. Shaft position feedback is developed and connected to the electronic control.
    Type: Grant
    Filed: August 30, 1982
    Date of Patent: May 7, 1985
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Ralph A. Hannmann, Jr., James F. Higginbotham
  • Patent number: 4339984
    Abstract: The drive comprises an air-operated driving unit imparting either a linear or a rotary motion to the working member of a manipulator and, at the same time, driving the rotor of an electromagnetic brake in accordance with displacement of the working member. For linear movement of the working member, the driving unit comprises an air-operated piston-cylinder actuator and, for rotary movement of the working member, comprises a vane-type air motor. An electronic control system controls the operation of the driving unit and of the electromagnetic brake, and thus the motion of the working member.
    Type: Grant
    Filed: November 1, 1979
    Date of Patent: July 20, 1982
    Assignee: G. H. Pfaff Pietzsch Industrieroboter
    Inventor: Gerd Huhne
  • Patent number: 4131189
    Abstract: To permit safe operation of clutch actuated moving ram machines, especially when the operator is to be permitted to "float" the ram, the operating linkage to the clutch is formed with a connection which requires input motion of the linkage in predetermined degree to actuate a safety mechanism. The purpose is to prevent ram operation until the operator is out of harm's way. The linkage is formed such that additional motion of the input elements to the clutch is ineffective to actuate the clutch until the safety apparatus is properly positioned whereupon such additional motion of the input member is made effective to actuate the clutch. An apparatus effective to perform according to that method comprises a piston and a cylinder capable of movement relative to one another and both capable of movement relative to a frame on which the clutch is mounted.
    Type: Grant
    Filed: April 13, 1977
    Date of Patent: December 26, 1978
    Inventor: Daniel R. Stephens
  • Patent number: 4106390
    Abstract: A digitally controllable pneumatic linear actuator in which a moving piston driven by compressed air is initially decelerated by the pressure of compressed air applied to the both sides thereof in the course of its advancing movement toward a predetermined stop position and is then braked by a mechanical brake, thereby obviating failure of precise positioning of the piston due to the compressibility of air. The piston displacement is digitally detected, and the result of detection is fed back to a digital controller.
    Type: Grant
    Filed: November 24, 1976
    Date of Patent: August 15, 1978
    Assignee: Kuroda Seiko Co., Ltd.
    Inventors: Hiroshi Kodaira, Mitsuo Masuda
  • Patent number: 4102248
    Abstract: This disclosure relates to a system for protecting pneumatic cylinders and diaphragm valves against failure of both electrical and pneumatic supplies. In the event of a failure of the air supply, the loss of air pressure is detected and all drives are locked in position. The position pneumatic feedback signal from the pneumatic cylinder diaphragm valve is then connected directly to a pneumatic memory. Thus when the air supply recovers, the pneumatic memory will be equal to the instantaneous position of the pneumatic cylinder or diaphragm valve.In the event of an electrical failure, a solenoid valve interrupts the flow of the pneumatic signal from an electropneumatic transducer to the pneumatic memory, so that the air cylinder or valve is directly connected to the pneumatic memory. By selectively energizing a pair of solenoid valves connected to the memory, the operator using an emergency d.c.
    Type: Grant
    Filed: March 8, 1976
    Date of Patent: July 25, 1978
    Assignee: Westinghouse Electric Corp.
    Inventor: Lyle F. Martz
  • Patent number: 4050674
    Abstract: A hydraulic jack comprising a cylinder, a piston slidable relative to the cylinder, pump means to supply pressurized fluid to the base of the piston, a seal between the piston and the cylinder, means for limiting the stroke of the piston in the cylinder, said means comprising a ring carried by the piston and arranged to expand into a groove in the cylinder wall when the piston reaches the end of its permitted travel, and means for selectively de-activating said stroke limiting means, in order to allow removal of the piston from the cylinder to renew the seal.
    Type: Grant
    Filed: December 27, 1976
    Date of Patent: September 27, 1977
    Assignee: Tangye Limited
    Inventors: Joseph Henry Robbins, deceased, John Edward Acton
  • Patent number: 4016803
    Abstract: The invention relates to a servo assembly having a stationary part including a housing, a movable member and a servo motor. Of primary interest is the stopping mechanism which includes a stop unit on the movable member and two pressure operated, vertically reciprocal stop members mounted in the housing. Two hydraulic circuits are provided with a first circuit for the two stop members and the second circuit for the servo motor. Throttle valving for the first circuit is provided between the two stop members and the housing. Prior to reaching a stopping position the stop unit on the movable member actuates a switch which relieves the pressure in the first circuit and causes one of the stop members to descend to an intermediate position where throttling occurs and the other stop member to descend to a final position where throttling may or may not occur. The throttling causes substantial braking of the movable member during a short distance of travel just prior to the stopping position being reached.
    Type: Grant
    Filed: November 10, 1975
    Date of Patent: April 12, 1977
    Assignee: Danfoss A/S
    Inventor: Svend Ove Soby