Patents Represented by Law Firm Zalkind & Shuster
  • Patent number: 4800772
    Abstract: A plurality of control rods (41, 43, and 42, 44) extend transversely of a locking plate (3) through which at least three of the control rods are locked in a neutral position by cammed displacement of the locking plate in response to axial displacement of another of the control rods from the neutral position. Locking grooves (45) in the control rods are aligned in the neutral position and the rods are engaged therein by locking edges (31, 32) formed on the locking plate facing opposite directions for either cammed displacement of the locking plate or locking of the rods. The locking plate is displaceable within a housing (11) along a path transverse to the control rods and about a pivot axis (52) fixed to the housing.
    Type: Grant
    Filed: August 4, 1987
    Date of Patent: January 31, 1989
    Assignee: Zahnradfabrik Friedrichshafen, AG
    Inventors: Wolfgang Irlbacher, Gerhard Buri
  • Patent number: 4784041
    Abstract: A steering control piston valve has reaction chambers and respective fixed restrictor orifices having an interconnector conduit. The reaction chambers have respective inlet and outlet flow control valving which serve to permit flow from either reaction chamber to bypass the respective restrictor orifice during a steering maneuver if the steered wheels receive a road jolt. The arrangement provides for very rapid flow from the reaction chamber being decreased in volume due to the jolt force on the valve piston causing it to move oppositely to the steering direction. The flow from such reaction chamber passes to the interconnecting conduit for storage. An additional storage tank can be connected to the interconnecting conduit to increase the storage capacity if necessary. The bypassing is likewise advantageous in the event a vehicle swerves and rapid steering correction is necessary.
    Type: Grant
    Filed: August 5, 1986
    Date of Patent: November 15, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Armin Lang
  • Patent number: 4777837
    Abstract: A transmission is provided for transfering power from an input shaft to an output shaft in a large number of ratios derived by the use of main gear groups, a range gear group and a reversing gear. Power is provided by either of two power paths thus making possible shifting under load. A friction clutch selects one or the other of the power paths and synchronizing clutches select which of a plurality of ratios will be provided by the selected path. While driving in one path, the next ratio is selected in the other path and at a selected time power is shifted from one path to the other. Because the transmission provides several ranges of ratios and several ratios in each range including a reverse in each ratio, a vehicle using this transmission may be used for a plurality of tasks and be efficient at each. By using duplicate parts and multiple shafts the transmission can be provided in a compact size and at a reduced cost.
    Type: Grant
    Filed: March 3, 1987
    Date of Patent: October 18, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Hubert Lehle
  • Patent number: 4774847
    Abstract: Rotary pressure control valves in booster steering systems are rotated by manual force at the steering wheel against a return force, usually a steel torque rod which is twisted by rotation of the steering wheel. Upon release of steering force, the untwisting of the rod causes reverse rotation toward neutral shut-off, i.e., centered position, so that coacting pressure channels of relatively rotated valve components are closed. Such reverse rotation is effected herein with the aid of a metal bellows which is compressed by cam operation during twisting of the torque rod. Upon untwisting, the bellows expands and acts through the cam to exert a reverse rotary force on the valve components to effect complete centering. Upon reaching centered valve position, the cam serves as a detent to hold the centered position of the valve components.
    Type: Grant
    Filed: June 16, 1987
    Date of Patent: October 4, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Werner Breitweg
  • Patent number: 4772190
    Abstract: A vane cell pump comprises a housing having a small bore at one end extending to a large bore at the other end. A drive shaft for a pump package, i.e., a rotor, vanes and cam ring in said large bore. The other end of the housing is closed by a pressure plate against which one radial face of the pump package rotates, and which pressure plate is bolted to the housing. Another pressure plate within the large bore is pressed against the opposite radial face of the pump package by being exposed to an outlet pressure chamber of the pump. The area of the outlet pressure chamber to which the latter pressure plate is exposed is demarcated by axial sealing elements surrounding the drive shaft and exerting a compression force between a housing wall and the latter pressure plate. The construction effects a tight tolerance between relatively moving parts at all times including the start of pump operation.
    Type: Grant
    Filed: March 20, 1987
    Date of Patent: September 20, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventors: Merz, Johann, Eckard Keicher
  • Patent number: 4763091
    Abstract: A device for setting the air gap between an armature and an energizable electromagnet, which utilizes a pin that can be force fitted in the armature by a tool forcing it against spring bias for a distance limited to the thickness of a collar on the pin. In so doing, the spring is transformed from an unstressed to a stressed condition so that upon return movement of the spring the collar, pin, and armature are actuated a distance equal to the thickness of the collar thereby setting the air gap.
    Type: Grant
    Filed: April 2, 1987
    Date of Patent: August 9, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Armin Lang
  • Patent number: 4756330
    Abstract: In a flow divider valve for pressure feed to a hydraulic circuit for auxiliary power steering and to a hydraulic circuit for a power take-off the interior of a hollow regulator piston receives pressure feed for distribution to the hydraulic circuits. For one such circuit, preferably the power take-off, flow passes via multiple bores and coacting flow control grooves of the regulator piston and a housing in which it reciprocates. Accordingly, a desired flow quantity and pressure advantages are achieved, in comparison with use of a single flow control bore which would require a larger piston traverse causing delays in pressure build-up as well as oscillations and strong flow pulses and energy loss.
    Type: Grant
    Filed: March 18, 1987
    Date of Patent: July 12, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Werner Tischer
  • Patent number: 4752195
    Abstract: A vane type pump has an elongated pump housing through which the drive shaft of the pump passes. The usual components of the pump comprising a rotor which carries vanes within a cam ring is disposed between an inner end wall of the housing and a pressure plate wherein the pressure plate has pressure recesses or pockets. Damping chambers are provided in the elongated housing generally parallel to the drive shaft and substantially co-extensive with the housing bore that carries the drive shaft. Thus, very large volume damping chambers are provided for smoothing out pump pulsations in the course of operation.
    Type: Grant
    Filed: August 7, 1986
    Date of Patent: June 21, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventors: Peter Friedrich, Johann Merz
  • Patent number: 4742733
    Abstract: Automatic shift of a gear transmission under speed and load control between high and low drive ratio limits of a shift range, is effected in accordance with different sequential step change shift patterns selected from program storage. Different ones of the available drive ratios between the high and low limits of the shift range are skipped in the various shift patterns respectively corresponding to different travel loading conditions of a vehicle. Automatic shift operation is effected in accordance with the shift patterns selected to reduce the number of drive ratios utilized, such selections being made in accordance with the vehicle travel loading conditions.
    Type: Grant
    Filed: May 23, 1986
    Date of Patent: May 10, 1988
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Friedrich Schreiner
  • Patent number: 4715793
    Abstract: A rotary vane pump has a pressure operated valve to bypass pump outlet flow to the inlet of the pump for flow regulation. A metering throttle bore, downstream of a choke bore, responsive to viscosity is a passage from the pump to a consumer such as a servosteering system. Responsiveness to viscosity is effected by providing an area in cross section for flow passage in the metering bore, which flow area is much smaller than the wetted surface area of the passage. A pressure agent at a cold temperature having greater viscosity than that at a higher temperature will effect flow regulation of the pump sooner than the high temperature pressure agent. Since for a cold pressure agent the viscosity is higher, the resistance to flow through the metering throttle bore is greater. As a result, the pump must work at a higher pressure which actuates the pressure operated valve to effect bypass flow.
    Type: Grant
    Filed: April 3, 1986
    Date of Patent: December 29, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventors: Merz Johann, Seidl Gunther
  • Patent number: 4709666
    Abstract: A regulatable drive for speed control of the cooling fan of an internal combustion engine comprises fluid feed from a tank to the suction side of a pump via a suction passage wherein flow is controlled by a regulatable multi-position valve. The pump provides pressure feed to the suction side of a fluid motor that operates the fan. A bypass passage connects the suction passage of the fluid pump through the regulatable valve to the suction side of the fluid motor. The regulatable valve is actuated for control of suction feed to the pump responsive to fan speed via control circuitry which may also be responsive to engine temperature.
    Type: Grant
    Filed: March 6, 1986
    Date of Patent: December 1, 1987
    Assignee: Zahnradfabrik Friedrichshafen, Ag.
    Inventor: Johann Merz
  • Patent number: 4705129
    Abstract: Pressurized fluid from an engine driven pump is supplied to and exhausted from the opposed chambers of a hydrostatic power steering servomotor through control passages in a valve housing and in a rotatable valve body coupled through viscous liquid to a steering control shaft. A pressure signal from the pressurized chamber of the servomotor is supplied by the control passages to a valve between the pump and fluid reservoir to limit operating pressure as a function of servomotor loading.
    Type: Grant
    Filed: March 21, 1986
    Date of Patent: November 10, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Rolf Fassbender
  • Patent number: 4704939
    Abstract: A tone hole pad comprises a rigid backing disc but having a bendable margin and has at one face a recess between inner and outer coaxial collars to accommodate a cushion ring. Stretched across the radial faces of the collars and backed by the cushion ring is a membrane or skin as a sealing surface means that folds around the periphery of the rigid backing disc and is secured at the opposite face and is limited to a ringlike area. The support of the skin in a limited ringlike area on concentric collars effects a stability to resist and minimizes shrinkage or expansion, under ambient conditions, of the sealing surface that causes leakage. The periphery of the backing disc in one form of the invention is grooved to accommodate a tool for bending or marginally deforming one side of the disc to close leakage gaps caused by uneven contact on the rim of a tone hole. In a preferred form of the invention a similar but grooveless disc is backed by a non-bendable rigid disc.
    Type: Grant
    Filed: October 25, 1985
    Date of Patent: November 10, 1987
    Inventor: David Straubinger
  • Patent number: 4701111
    Abstract: A regulatable vane pump is provided with a piston operable by differential pressure responsive to booster steering flow demand wherein the piston movement controls a choke bore flow area. The differential pressure is effected by pump pressure on one face of the piston and consumer pressure on the opposite face of the piston, e.g., pressure in a booster steering servomotor. The choke bore has an aperture covered or uncovered by a choke plate carried by a pin on the piston. The choke plate is normally in position so as not to impede flow through the choke and the piston is in a position such that pump outlet flow is blocked from a bypass passage back to the pump inlet. However, with rise in vehicle speed under non-steering conditions, causing pressure on the one face of the piston to shift it along with the choke plate, the choke bore is closed, or partially so, and the unnecessary output pressure flow shunted back to pump inlet.
    Type: Grant
    Filed: March 6, 1986
    Date of Patent: October 20, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Gunther Seidl
  • Patent number: 4699231
    Abstract: A compact power steering device is provided wherein the power steering valving is actuated by axial movement of a pinion having helical teeth engaging a rack in a steering housing. The valving utilizes head and seat valves with valve heads and coacting valve seats which are actuated on axes parallel to the pinion axis within the housing and requiring no more than the overall distance occupied by axial movement of the pinion as effected by rotation of a steering wheel during steering. Opposed springs effect a centered position for the pinion in neutral position of the valving for straight ahead steering. Thus, a centering spring is dominant and limited in movement to fix the valving as biased by other springs to a precise neutral position.
    Type: Grant
    Filed: June 14, 1985
    Date of Patent: October 13, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventors: Armin Lang, Helmut Knodler
  • Patent number: 4685548
    Abstract: Control system for a pressure medium operated clutch (1) and reduction gear unit (4) to qualitatively improve torque reversal gear shifts by measurement of rotational speeds of the gear unit input shaft (41) and the turbine shaft (320) of a torque converter (3) through sensors (51, 52) and determination of differential speed conditions by an electronic unit (5) to which the sensors are connected. Upon displacement of the gear shift lever from neutral to gear drive position, the electronic unit issues a corrective fuel controlling command through line (22) for a length of time sufficient to obtain equality between the turbine speed (Nt) and the gear input speed (Ni) plus a correction factor (AN). The corrective command is applied to a control lever (71) of the engine fuel injection pump (7) through an automatic operating arrangement (90) superimposed on the fuel control linkage (8) connected to the control lever.
    Type: Grant
    Filed: June 18, 1986
    Date of Patent: August 11, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG
    Inventors: Otto Holtermann, Klaus Torbusch, Gerold Bieber
  • Patent number: 4676333
    Abstract: A pump is constructed using a magnetic piston in a cylinder having an oil feed thereto, for pumping oil to either pressure chamber of a steering servomotor. The pump cylinder has a chamber on each side of the pump piston which chambers discharge pressure oil into a respective servomotor chamber. The magnetic piston is actuated by an electromagnetic system under control of a manually operated steering wheel. The pump construction is such that the length of traverse of the pump piston on a pressure movement is shorter than the piston traverse of a servomotor chamber being pressurized. The pump chambers discharge directly into respective servomotor chambers without the need for steering control valving.
    Type: Grant
    Filed: February 6, 1986
    Date of Patent: June 30, 1987
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Johann Merz
  • Patent number: 4632641
    Abstract: A pump and a centrifugal impeller are arranged so that the pump has a suction line in which the centrifugal impeller is installed effecting a countercurrent opposite to the suction feed flow direction to the pump. The effect is to regulate the pump flow responsive to the speed of the centrifugal impeller so that the pump output flow decreases with rising pump speed.
    Type: Grant
    Filed: April 24, 1984
    Date of Patent: December 30, 1986
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Georg Liska
  • Patent number: 4621703
    Abstract: Simulated steering resistance is provided for the rotative valving control of a booster steering servomotor by providing the manually rotated section of the valving control which connects to a steering wheel with a coaxial reaction piston having faces exposed to operating pressures of the respective chambers of a double ended servomotor. The reaction piston is helically geared on the manually rotated section and restrained by a sliding keyway against rotation relative the valving control section conventionally connected by a torque rod to the manually rotated section. During steering, operating pressure on one face or the other of the reaction piston will cause it to shift and thereby effect a torque force on the manually rotated section due to the helical gearing which force opposes the manual steering force to thus simulate steering resistance.
    Type: Grant
    Filed: July 24, 1985
    Date of Patent: November 11, 1986
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventor: Werner Breitweg
  • Patent number: 4618017
    Abstract: A booster steering system has two pressure pumps for the booster cylinder, one of which is driven by the vehicle, with the wheels when the vehicle is rolling, and the other pump is driven by the vehicle engine. The vehicle driven pump is an emergency pump of non-variable displacement and can provide booster pressure flow to steer a vehicle off the road in an emergency should the engine driven pump fail. The engine driven pump is of variable displacement, normally maintained by an actuating means at zero stroke responsive to a pilot pressure from a steering control valve in neutral position with no steering pressure output. The vehicle driven pump normally provides the pressure output for steering. Accordingly, since most of the time the engine driven pump operates virtually pressurelessly there is no energy loss. When the vehicle is moving slowly in a tight curve a greater volume of output to the booster cylinder is needed and is provided by the engine driven variable displacement pump.
    Type: Grant
    Filed: November 21, 1984
    Date of Patent: October 21, 1986
    Assignee: Zahnradfabrik Friedrichshafen, AG.
    Inventors: Karl-Heinz Liebert, Erwin Wiedemann