With Independent Change Speed Gearing Patents (Class 74/15.4)
  • Patent number: 9284166
    Abstract: A self-propelled work machine, in particular a mobile crane, comprises an undercarriage configured for moving the work machine, a superstructure which is rotatably mounted on the undercarriage, and a drive device comprising a drive motor. The drive device comprises a moment transmission which is formed between the superstructure and the undercarriage and configured to transmit power outputted by the drive motor between the superstructure and the undercarriage in the form of a moment. At least one and, in particular, all of the elements to be driven receive a moment about an axis which extends in the region of a rotary bearing of the superstructure and the undercarriage, in particular about the rotational axis of the superstructure.
    Type: Grant
    Filed: September 27, 2013
    Date of Patent: March 15, 2016
    Assignee: Manitowoc Crane Group France SAS
    Inventor: Dieter Stuehrwoldt
  • Publication number: 20150090056
    Abstract: A power take off drive train for a utility vehicle, comprising first (31, 59), second (35, 55) and third (23, 68) parallel gear pairs, with an input shaft (8) coupled to a gear (31) of the first gear pair. First (K1) and second (K2) connector means, suitably clutches, each operate to couple a gear (31, 59) of the first gear pair with a respective gear (35, 55) of the second gear pair. A third connector (10, 11) couples a first gear (35) of the second gear pair with a first gear (23) of the third gear pair, and a selector mechanism (12) operates to couple a PTO output shaft (7) with either a second gear (55) of the second gear pair or a second gear (68) of the third gear pair.
    Type: Application
    Filed: November 7, 2013
    Publication date: April 2, 2015
    Inventor: Martin Brenninger
  • Patent number: 8984973
    Abstract: A power take off drive train for a utility vehicle, comprising first (31, 59), second (35, 55) and third (23, 68) parallel gear pairs, with an input shaft (8) coupled to a gear (31) of the first gear pair. First (K1) and second (K2) connector means, suitably clutches, each operate to couple a gear (31, 59) of the first gear pair with a respective gear (35, 55) of the second gear pair. A third connector (10, 11) couples a first gear (35) of the second gear pair with a first gear (23) of the third gear pair, and a selector mechanism (12) operates to couple a PTO output shaft (7) with either a second gear (55) of the second gear pair or a second gear (68) of the third gear pair.
    Type: Grant
    Filed: November 7, 2013
    Date of Patent: March 24, 2015
    Assignee: AGCO International GmbH
    Inventor: Martin Brenninger
  • Publication number: 20150053027
    Abstract: A power transmitting component having a actuator with a lead screw, which is driven by a motor and a transmission, a pusher assembly driven by the lead screw, and first and second clutch forks. Translation of the pusher coordinates movement of the first and second clutch forks along respective axes.
    Type: Application
    Filed: August 15, 2014
    Publication date: February 26, 2015
    Inventor: James P. Downs
  • Publication number: 20150013482
    Abstract: Power take off devices 10, 110, 210, 310 and 410 are disclosed. Each of the power take off devices include an integral planetary gear set coaxially arranged with the respective input shafts and output shafts of the devices to provide space efficient rotational torque at a large variety of large and small input to output ratios to a variety of accessory devices. The power take off devices 10 and 110 are two speed devices, and the power take off devices 210, 310 and 410 are single speed devices. In one embodiment, a power take off device 10 is mounted on and driven by a transmission of an over the highway truck to power a high speed blower mounted on the truck. The device 10 includes an input shaft 36 that meshes with and is driven by a gear in the transmission and an output shaft 37 that drives the blower. The shafts 36 and 37 are mechanically connected through a planetary gear set 52.
    Type: Application
    Filed: September 30, 2014
    Publication date: January 15, 2015
    Inventors: Stephen D. Horsfall, John Loeffler
  • Patent number: 8733191
    Abstract: A drive arrangement is disclosed for a motor vehicle power take off (PTO). The arrangement comprises a PTO shaft 104,158,207 of a known type intended for coupling to a power driven implement. An input shaft is arranged to be coupled to a rotary driver such as an engine. A continuously variable transmission such as 10 is coupled between the input and PTO shafts to transfer drive between them at a continuously variable ratio. In accordance with the invention, the continuously variable transmission is constructed and arranged such as to regulate torque and to automatically accommodate changes in speed at the PTO Shaft by virtue of changes in its drive ratio.
    Type: Grant
    Filed: April 21, 2006
    Date of Patent: May 27, 2014
    Assignee: Torotrak (Development) Limited
    Inventor: Robert Andrew Oliver
  • Patent number: 8661925
    Abstract: A hydraulically operated shifter for use in a power take-off includes a shifter housing having an interior, a fluid port, and an opening. A shifter piston is disposed within the interior of the shifter housing and is movable in first and second directions. The shifter piston defines first and second chambers within the interior of the shifter housing. The fluid port communicates with the first chamber, and the opening communicates with the second chamber. The shifter piston includes a passageway that provides communication between the first and second chamber defined within the interior of the shifter housing. A shift actuator is supported on the shifter piston for movement therewith and extends through the opening provided in the shifter housing.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: March 4, 2014
    Assignee: Parker Hannifin Corporation
    Inventor: Damon B. Graves
  • Publication number: 20130338887
    Abstract: A method of operating a multi-mode drive system that precisely orchestrates a shift between gear ratios in a power take off unit and a rear drive module. The method first shifts between gear ratios in the power take off unit and then, depending upon the success or failure of the shift of the power take off unit, shifts between gear ratios in the rear drive module.
    Type: Application
    Filed: June 18, 2012
    Publication date: December 19, 2013
    Applicant: Chrysler Group LLC
    Inventors: Joseph E. Kubina, Aaron E. Thompson, Donald F. Schmanski, Michael W. Gapski, Kenneth M. Pachucki, Richard S. Silbert
  • Publication number: 20130283939
    Abstract: A two-speed power take-off unit adapted for installation in an all-wheel drive vehicle having a transversely mounted engine/transaxle powertrain. The two-speed power take-off unit includes a planetary gear reduction unit capable of establishing a high-range and a low-range drive connection between the powertrain and a transfer assembly. The transfer assembly provides drive torque to a front differential assembly driving the front wheels and a PTU gearset driving the rear wheels.
    Type: Application
    Filed: June 26, 2013
    Publication date: October 31, 2013
    Inventors: Todd Ekonen, Douglas Bradley
  • Patent number: 8561490
    Abstract: A farm vehicle power take-off device, in particular for a tractor, wherein an output shaft is connected selectively by a drive to a first and second input shaft rotating at different speeds. The selective connection is made by moving a selector sleeve between three settings, in a first and second of which, the output shaft is connected to the first shaft to rotate at a first and second angular speed respectively, and, in a third of which, the output shaft is connected to the second shaft to rotate at a third angular speed different from the first and second angular speed.
    Type: Grant
    Filed: April 13, 2008
    Date of Patent: October 22, 2013
    Assignee: CNH America LLC
    Inventors: Giancarlo Benassi, Ivan Tioli
  • Patent number: 8534396
    Abstract: A tractor power take-off drive line having an output shaft (11) with a socket (12) within which a removeable PTO stub shaft (13) is drivingly received. The stub shaft is retained in the socket by radially moveable retaining members (16) housed in the output shaft and moveable between a radially inward retaining position in which the retaining members each projecting into the socket (12) to engage a retaining formation (18) in the stub shaft (13) within the socket and a radially outward releasing position in which the retaining members are free to move radially outwardly relative to the socket to disengage the retaining formation and allow the stub-shaft to be removed from the socket.
    Type: Grant
    Filed: September 3, 2009
    Date of Patent: September 17, 2013
    Assignee: Agco SA
    Inventors: Guillaume Schulz, Vincent Hedin
  • Publication number: 20130180346
    Abstract: A drive system for an agricultural work vehicle. The drive system includes a front power takeoff device configured to extend from a front portion of the agricultural work vehicle and to be driven by an engine. The drive system also includes a first gearbox and a second gearbox positioned between the engine and the front power takeoff device. The first gearbox is configured to be driven by the engine and to provide power to drive the second gearbox. The second gearbox is configured to be driven by the first gearbox and to provide power to drive the front power takeoff device. The first gearbox and the second gearbox each provide a vertical shift between a respective driven input and a respective driving output.
    Type: Application
    Filed: April 3, 2012
    Publication date: July 18, 2013
    Applicant: CNH America LLC
    Inventors: Thomas B. Tuttle, Edmund R. Henket, Benjamin L. McCash
  • Patent number: 8393236
    Abstract: A modular drive system for a zero turn radius vehicle having a central gear box with a vertical input shaft, a central drive train that powers a variety of left and right side drive mechanisms, and a power take off mechanism having a clutch and brake assembly. The vertical input shaft is a through-shaft design that allows the central gear box to be mounted with either end of the through-shaft oriented in an upward direction. A screw-on filter acts in conjunction with a charge pump to remove debris from the central gear box's hydraulic fluid.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: March 12, 2013
    Assignee: Hydro-Gear Limited Partnership
    Inventors: Raymond Hauser, Nathan W. Bonny, Michael L. Bennett
  • Patent number: 8206055
    Abstract: A coupling mechanism secures a shaft-to-collar connection for two shafts, such as an extension shaft stub and a tractor PTO shaft. An annular locking element on the first shaft prevents an axial disconnection of an established connection. One of the shafts has a collar with a positive engagement element for a locking engagement with the other shaft. The other shaft includes a positive engagement for a locking engagement with the collar. To enable an easier handling of the axial locking of the shaft to collar connection, the locking element includes a first set of teeth which are complementarily to a second set of teeth on the second shaft. The locking element is rotatably arranged on the first shaft and can be rotated from a locked position to an unlocked position. In the locked position the teeth overlap.
    Type: Grant
    Filed: October 26, 2006
    Date of Patent: June 26, 2012
    Assignee: Deere & Company
    Inventors: Helmut Schäfer, Holger Schmitt
  • Patent number: 8096200
    Abstract: In a tractor which detachably mounts a PTO portion on a transmission portion, a PTO clutch mechanism is arranged in the inside of the PTO portion. Accordingly, a specification which includes the PTO clutch mechanism or a specification which includes no PTO clutch mechanism is selectable depending on whether the PTO clutch mechanism is preliminarily assembled in the PTO portion or not, in a stage at which the PTO portion is assembled. It is also later possible to easily complete assembly by merely mounting the PTO portion on the transmission portion. Further, by reversing the assembly steps, it is possible to easily perform maintenance of the PTO clutch mechanism or other related components.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: January 17, 2012
    Assignee: Yanmar Co., Ltd.
    Inventor: Tatsuo Yamaguchi
  • Patent number: 7874222
    Abstract: A power take-off assembly for a work vehicle including an improved power take-off shaft for installation and removal. The power take off shaft is extended and a cut out section on the first end of the shaft is provided to engage an extended portion of a spring loaded mechanism. Once the cut out section securely fits over the extended portion, the spring loaded mechanism is prevented from axially moving in a rightward direction, thus enabling the spring to hold the gear collar in place to engage the high speed gear. The PTO stub shaft has an extended end with protruding shoulders which serve to capture the snap ring between the stub shaft and the output shaft so that when the stub is moved axially the shoulders will pull the snap ring into the groove on the output shaft which securely fastens the stub shaft. A cut-out section on the front end surface of the output shaft is also provided to allow clearance for the tool to squeeze the snap ring tabs during installation and removal.
    Type: Grant
    Filed: April 19, 2007
    Date of Patent: January 25, 2011
    Assignee: Deere & Company
    Inventors: David M. Steele, John A. Weihs, Allan N. Schott, Daniel J. Fox, Wade T. Larson
  • Patent number: 7673712
    Abstract: A power transmission system for a working vehicle comprises: a vehicle frame; a prime mover mounted on the vehicle frame; a pair of left and right drive wheels; a pair of left and right transaxles juxtaposed on the vehicle frame, wherein each of the left and right transaxles includes a single axle for individually driving each of the left and right drive wheels in forward and rearward directions; a working device; and a working power clutch unit disposed between the left and right transaxles so as to clutch on/off power transmitted from the prime mover to the working device.
    Type: Grant
    Filed: September 13, 2006
    Date of Patent: March 9, 2010
    Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd.
    Inventors: Masaru Iida, Hideki Kanenobu, Ryota Ohashi
  • Publication number: 20090312145
    Abstract: Embodiments are directed to a front end accessory drive (FEAD), subassemblies, and components therefor. Embodiments disclosed cover power modulating devices (PMD) which can be used in a FEAD. In one embodiment, a continuously variable transmission (CVT) is coupled directly to a crankshaft of a prime mover, and the CVT is used to regulate the speed and/or torque delivered to an accessory. A compound drive device includes a motor/generator subassembly cooperating with a CVT subassembly to provide a motor functionality with torque multiplication or division, or alternatively, a generator functionality with torque multiplication or division. In some embodiments, a FEAD includes a PMD having a sun shaft configured to couple to a sun of the PMD and to an electric motor component, such as an electrical armature or an electrical field. In one embodiment, the electrical armature the electrical field are placed concentrically and coaxially and configured to rotate relative to one another in opposite directions.
    Type: Application
    Filed: June 21, 2007
    Publication date: December 17, 2009
    Applicant: FALLBROOK TECHNOLOGIES INC.
    Inventors: Brad P. Pohl, Donald C. Miller, Robert A. Smithson, Jeremy Carter, Charles B. lohr
  • Publication number: 20090305840
    Abstract: A drive arrangement is disclosed for a motor vehicle power take off (PTO). The arrangement comprises a PTO shaft 104,158,207 of a known type intended for coupling to a power driven implement. An input shaft is arranged to be coupled to a rotary driver such as an engine. A continuously variable transmission such as 10 is coupled between the input and PTO shafts to transfer drive between them at a continuously variable ratio. In accordance with the invention, the continuously variable transmission is constructed and arranged such as to regulate torque and to automatically accommodate changes in speed at the PTO Shaft by virtue of changes in its drive ratio.
    Type: Application
    Filed: April 21, 2006
    Publication date: December 10, 2009
    Applicant: Torotrak (Development) Ltd.
    Inventor: Robert Andrew Oliver
  • Publication number: 20090293652
    Abstract: An apparatus comprising a power take-off shaft includes an outer shaft and an inner shaft. The outer shaft includes an outer periphery and an inner periphery. The inner shaft includes an outer periphery and an inner periphery. A notch is configured around at least a portion of the outer periphery of the inner shaft, and a self-lubricating material is disposed on at least a portion of the notch.
    Type: Application
    Filed: May 28, 2008
    Publication date: December 3, 2009
    Inventor: Warren D. Williamson
  • Patent number: 7484580
    Abstract: The present invention aims at making a transmission casing compact. In the present invention, in the inside of a transmission casing, a traveling-system power transmission mechanism which is interposed between an engine and an axel, a PTO-system power transmission mechanism which is interposed between the engine and a PTO shaft, and a changeover mechanism which is interposed between both power transmission mechanisms are provided, wherein the power transmission of the PTO-system power transmission mechanism is interrupted at a middle portion thereof by the changeover mechanism and, at the same time, the changeover mechanism is allowed to perform a changeover manipulation to connect a downstream side portion of the PTO-system power transmission mechanism and a downstream side portion of the traveling-system power transmission mechanism.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: February 3, 2009
    Assignee: Yanmar Co., Ltd.
    Inventors: Tatsuo Yamaguchi, Noboru Yamamoto, Bunei Katagiri, Keiichi Hayashi
  • Publication number: 20080264188
    Abstract: A hydraulically operated shifter for use in a power take-off includes a shifter housing having an interior, a fluid port, and an opening. A shifter piston is disposed within the interior of the shifter housing and is movable in first and second directions. The shifter piston defines first and second chambers within the interior of the shifter housing. The fluid port communicates with the first chamber, and the opening communicates with the second chamber. The shifter piston includes a passageway that provides communication between the first and second chamber defined within the interior of the shifter housing. A shift actuator is supported on the shifter piston for movement therewith and extends through the opening provided in the shifter housing.
    Type: Application
    Filed: April 30, 2008
    Publication date: October 30, 2008
    Inventor: Damon B. Graves
  • Publication number: 20080257078
    Abstract: A power take-off assembly for a work vehicle including an improved power take-off shaft for installation and removal. The power take off shaft is extended and a cut out section on the first end of the shaft is provided to engage an extended portion of a spring loaded mechanism. Once the cut out section securely fits over the extended portion, the spring loaded mechanism is prevented from axially moving in a rightward direction, thus enabling the spring to hold the gear collar in place to engage the high speed gear. The PTO stub shaft has an extended end with protruding shoulders which serve to capture the snap ring between the stub shaft and the output shaft so that when the stub is moved axially the shoulders will pull the snap ring into the groove on the output shaft which securely fastens the stub shaft. A cut-out section on the front end surface of the output shaft is also provided to allow clearance for the tool to squeeze the snap ring tabs during installation and removal.
    Type: Application
    Filed: April 19, 2007
    Publication date: October 23, 2008
    Inventors: David M. Steele, John A. Weihs, Allan N. Schott, Daniel J. Fox, Wade T. Larson
  • Patent number: 7421917
    Abstract: A tractor with a PTO apparatus, comprises: a plurality of wheels; a vehicle body supported by the plurality of wheels; an engine supported on the vehicle body; a rear PTO shaft disposed at a rear of the vehicle body for transmitting power from the engine; a mid-PTO shaft disposed under the vehicle body for transmitting power from the engine; a PTO mode selecting device having a first position for transmitting power only to the rear PTO shaft, a second position for transmitting power to both the rear PTO shaft and said mid-PTO shaft, and a third position for transmitting power only to said mid-PTO shaft; a PTO clutch disposed on a transmission line upstream of said PTO mode selecting device and switchable between an engaged position and a disengaged position; and a restricting mechanism for preventing a change operation of said PTO mode selecting device when said PTO clutch is in the engaged position, and permitting the change operation of said PTO mode selecting device when said PTO clutch is in the disengage
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: September 9, 2008
    Assignee: Kubota Corporation
    Inventors: Akifumi Nishino, Ryuji Kitagawa, Kiyokazu Nakanishi, Tsukasa Wada, Kenzo Ushiro
  • Patent number: 7270023
    Abstract: A transmission for a vehicle is proposed which comprises one main transmission MT with one input shaft (1) and one output shaft (2), the same as at least one range change group (3) and one power take off, wherein one countershaft (5) integrated in the range change group (3) for actuating a power take off, the countershaft (5) being connectable, via a gear change sleeve unit (6), with the input shaft (1) and the output shaft (2) and the power take off can be driven independently of the operating state of the vehicle.
    Type: Grant
    Filed: August 12, 2003
    Date of Patent: September 18, 2007
    Assignee: ZF Friedrichshafen AG
    Inventor: Thomas Kramer
  • Patent number: 6854541
    Abstract: A reversible PTO shaft having opposite splined ends whose numbers of teeth are different from each other is inserted at one of the splined ends into an output sleeve and not-relatively rotatably connected to the output sleeve. For constituting at a position out of the PTO transmission system an actuator for changing the rotary speed of the output sleeve and holding the output sleeve changed in rotary speed simultaneously to the reversing of PTO shaft, a second collar connected to a shifter collar for changing the rotary speed of output sleeve so as to be slidable integrally with the shifter collar is disposed on an inner end of the output sleeve. When the splined end of PTO shaft having the greater number of teeth is inserted into the output sleeve, a sensor having a cam surface is moved by an end surface of the PTO shaft so as to make a pin project from the output sleeve, thereby holding the second collar at its low speed position.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: February 15, 2005
    Inventors: Mizuya Matufuji, Gen Yoshii
  • Publication number: 20040244514
    Abstract: A transmission for a work vehicle having PTO function is disclosed. The transmission includes a first transmission shaft for receiving engine power through a PTO power train, a second transmission shaft for receiving, the engine power through a traveling power train, the second transmission shaft being coupled to a rear differential mechanism, a third transmission shaft coupled to a rear PTO, a fourth transmission shaft for receiving force from the second transmission shaft, a first gear transmission mechanism for transmitting the force from the first transmission shaft to, the third transmission shaft. The first gear transmission mechanism has an input gear mounted on the first transmission shaft, an output gear mounted on the third transmission shaft and a relay gear loosely mounted on the second transmission shaft for transmitting the force from the input gear to the output gear.
    Type: Application
    Filed: March 9, 2004
    Publication date: December 9, 2004
    Applicant: KUBOTA CORPORATION
    Inventors: Masayori Kajino, Tatsuyuki Kashimoto, Megumi Sawai
  • Patent number: 6692395
    Abstract: A PTO transmission includes a split power transmission unit having an output member connected to a PTO shaft, a first input connected to an engine output shaft and a second input connected the output of a variable speed drive unit. A control unit controls the speed of the variable speed drive unit as a function of sensed engine speed and maintains the PTO shaft at a constant speed. The split power transmission is preferably a planetary gear unit. The variable speed drive unit preferably includes a variable displacement hydrostatic pump driving a fixed displacement hydrostatic motor which drives a sun gear of the planetary gear unit. This system transmits power to the PTO shaft from both the engine and from the variable speed drive unit. The control unit may also control the variable speed drive unit so that the speed of the PTO shaft is maintained at a desired ratio with respect to the ground speed, or so that the speed of the PTO shaft is maintained at a speed set by an operator.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: February 17, 2004
    Assignee: Deere & Company
    Inventors: Reno Antonio Rodeghiero, Werner Stettler, Graham Thompson, Barbara Klabunde, Andrey Valeryevich Skotnikov
  • Patent number: 6659209
    Abstract: A tractor having a mid-mount type mower includes a pair of frames extending in a fore and aft direction, and a transmission case extending and supported between the pair of frames. The transmission case houses a power take off clutch disposed above a rear wheel differential. A change speed gearing mechanism is disposed between a front surface of the transmission case and the rear wheel differential. With such an arrangement of the components, the transmission case has a reduced length in the fore and aft direction.
    Type: Grant
    Filed: September 25, 2002
    Date of Patent: December 9, 2003
    Assignee: Kubota Corporation
    Inventors: Masashi Osuga, Takashi Yoshii, Hiroshi Shimada
  • Patent number: 6629470
    Abstract: A tractor includes a frame, an engine, a transmission for selecting a number of vehicle speeds, and a device for transmitting power from the engine to a PTO mechanism. The tractor has a mechanism forming part of the device by which the tractor speed can be selected to be higher than any speed selectable by means of the transmission.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: October 7, 2003
    Assignee: New Holland North America, Inc.
    Inventor: Emiliano Brancolini
  • Patent number: 6523429
    Abstract: A power take off drive train for an agricultural tractor includes at least one input shaft and an output shaft that are rotatably mounted in a transmission casing, wherein the gear train provides for the output shaft to be rotated at one of three selected speeds, one of the at least one input shafts mounting first and second input gear wheels and a selector, the gear wheels being free to rotate on the shaft, and wherein the selector is mounted on the shaft for rotation therewith, and to slide axially along the shaft to engage with one of the first and second gear wheels transmitting torque thereto, and wherein the output shaft mounts first and second output gear wheels fixed for rotation therewith, the first and second output gear wheels being in driving engagement with the first and second input gear wheels respectively, and wherein the drive train further comprises a third output gear wheel that engages with a third input gear mounted on an input shaft mounted in the transmission casing, wherein drive to th
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: February 25, 2003
    Assignees: AGCO SA, Renault Agriculture SA
    Inventors: Emmanuel Desmarchelier, Philippe Baudet, Fabrice Collin
  • Patent number: 6318485
    Abstract: A tractor having a mid-mount type mower includes a pair of frames extending in a fore and aft direction, and a transmission case extending and supported between the pair of frames. The transmission case houses a power takeoff clutch disposed above a rear wheel differential. A change speed gearing mechanism is disposed between a front surface of the transmission case and the rear wheel differential. With such an arrangement of the components, the transmission case has a reduced length in the fore and aft direction.
    Type: Grant
    Filed: November 19, 1998
    Date of Patent: November 20, 2001
    Assignee: Kubota Corporation
    Inventors: Masashi Osuga, Takashi Yoshii, Hiroshi Shimada
  • Patent number: 6199653
    Abstract: A four-wheel driven wheel has a rear-wheel driving system branching at the intermediate thereof into a front-wheel driving system comprising a first transmission for driving the front wheels at a peripheral speed substantially identical with that of the rear wheels and a second transmission for driving the front wheels at a peripheral speed higher than that of the rear wheels. A hydraulic clutch device is provided, including a hydraulically operable first friction clutch for connecting and separating the first transmission with the rear-wheel driving system, a hydraulically double-acting first piston for engagement and disengagement of the first friction clutch, a first fluid chamber for the clutch-engaging action provided at one side the first friction clutch, a second fluid chamber for the clutch-disengaging action provided at the other side thereof, and a biasing member for biasing the first friction clutch to engage disposed in the first chamber.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: March 13, 2001
    Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd.
    Inventors: Mizuya Matsufuji, Masahisa Kawamura