Abstract: A work vehicle includes a vehicle body, a work implement including an attachment, an operating device and a controller. The operating device can be operated to a dump side and a tilt side to cause the attachment to dump and tilt. The controller executes an automatic drive control in which the attachment is caused to dump as far as a predetermined dumping position when the operating device is operated by a first dump operation amount or greater to the dump side, or to tilt as far as a predetermined tilt position when the operating device is operated by a first tilt operation amount or greater to the tilt side. The controller disables the automatic drive control when a switching time period required for the operating device to be switched between the tilt and dump sides is at least a predetermined disabling time period.

Abstract: A compact utility loader is operated by a standing operator at the rear of a frame. A loader arm assembly comprises a scissors linkage on either side of the frame nesting around the prime mover. Each scissors linkage has an upper loader arm that is pivoted at its rear end to rears ends of a pair of lower loader arms such that the pivot connections to the upper loader arm move upwardly and forwardly relative to the frame during elevation of the loader arm assembly to provide a high lift capability. The frame is self-propelled by a differential drive and steering system that is operated by dual levers. A hand grip extends between and unifies the operation of the levers to permit the operator to more easily move the levers in the ways that are needed to provide either straight motion of the frame or turns of the frame.

Abstract: A self-leveling front-end loader for attachment to a tractor. The self-leveling front-end loader includes a support structure configured to be attached to the tractor, and two extendable booms, each boom including a proximal leg, a distal leg, and a self-leveling hydraulic linkage configured to maintain the tilt angle of an accessory, such as a bucket. Each extendable boom has a boom extension hydraulic cylinder for extending the boom by up to 2 to 4 feet, a lift hydraulic cylinder to lift each boom, a self-leveling hydraulic cylinder, and a tilt hydraulic cylinder to tilt the accessory. The extendable booms enhance the capability of the front-end loader to position payload higher and farther than a standard front end loader, while preserving the stability and lifting capacity of the front-end loader. The booms have a traditional “dogleg” bend of 105 to 135 degrees, providing the two booms a wide range of motion.

Abstract: A control device for a construction machine includes an operational amount data acquisition unit configured to acquire operational amount data indicating an operational amount of the working unit, an operation determination unit configured to determine a non-operation state of a bucket on the basis of the operational amount data, a bucket control determination unit configured to determine whether bucket control conditions are satisfied, on the basis of determination of the non-operation state, and a working unit control unit configured to output a control signal for controlling the bucket to maintain a state of the working unit, when the bucket control conditions are determined to be satisfied.

Abstract: A remote angular position display system and method are disclosed. The angular position of a work implement of a work vehicle is displayed (e.g., textually, numerically or graphically) on a display associated with a portable device. The angular position is observed by a sensor coupled to the work implement or the work vehicle. The method includes receiving, by a processor of the portable device, one or more signals from the sensor indicative of an angular position value, and determining, by the processor, a condition associated with the work implement based on the angular position. The method includes outputting, by the processor, an interface for rendering on the display associated with the portable device that indicates the angular position and the determined condition associated with the work implement of the work vehicle.

Abstract: A flexible suction device and a robot system using the same are provided. The flexible suction device includes a flexible tube portion, and a suction cup connected to one end of the flexible tube portion, such that the suction cup may grasp an object by a suction force. The flexible tube portion is controllable to switch between a straight state and at least one bending state, such that the flexible tube portion is configured to bend from the straight state to the at least one bending state in order to swing and flip the object being grasped by the suction cup. In operation, the flexible suction device is controlled to grasp and lift the object in the straight state, and then switch to the bending state in order to swing the object being grasped. Thus, the flexible suction device may release the object, such that the object is flipped.

Abstract: A method is provided for determining the vertical position of at least a point of a ground portion using a work machine including an implement. The work machine further includes a position determining arrangement adapted to determine at least the vertical position of the implement and a force determining arrangement adapted to determine a force applied to the implement. The method includes determining a contact force value indicative of a contact force between the ground portion and the implement using the force determining arrangement, determining whether or not the contact force value is within a predetermined contact force value range, and if it is determined that the contact force value is within the predetermined contact force value range, using the position determining arrangement for determining at least the vertical position of a portion of the implement which is in contact with the ground portion.

Abstract: The present disclosure is directed to a work vehicle such as a loader having a bucket attached to the lift arms of a lift assembly and including a system and method for controlling the operation of the lift assembly so as to enable the loader to move over varying terrain without spilling the contents of the bucket. The system includes a chassis sensor, a bucket sensor, a gravity sensor, and a control system for varying the position of the bucket. The system adjusts the bucket's orientation via the control system to maintain a 90 degree difference between the bucket vector and the gravity vector.

Abstract: A method of operating a digging machine, including damping the response of a boom hydraulic cylinder operationally connected to a boom arm and actuating a bucket hydraulic cylinder operationally connected to a bucket.

Abstract: A system for locating a work vehicle at a job site, locating a topographic feature with respect to the work vehicle, and further characterizing the topographic feature from the work vehicle.

Abstract: A work vehicle includes a pair of booms, a link mechanism and a control unit. The booms are attached to a front part of a vehicle body in an upwardly and downwardly rotatable state. The link mechanism couples a working unit to tips of the booms. The link mechanism is configured to keep the working unit in a posture generally parallel to the ground without rotating the working unit with respect to the ground while the booms are elevated from a position where the working unit is disposed on the ground when the working unit is a fork. The control unit is configured to execute a tilt angle adjusting control for the working unit in accordance with variation in an angle of the booms while the booms are elevated when a tilt angle of the working unit is greater than or equal to a predetermined threshold.

Abstract: A method of operating a working machine which includes a main structure and a working arm pivotally mounted at one end on the main structure. The working arm is raisable and lowerable relative to the main structure by a first actuator device, and is extendible relative to the main structure by a second actuator device. In use, the arm carries at another end a working implement which can carry a load. The machine further including a ground engaging drive structure by which the machine is drivable on the ground. The machine has a longitudinal load moment control system which automatically disables operation of the first and/or second actuator devices from increasing longitudinal instability in the event that a predetermined instability is sensed. When the machine senses a ground travelling speed above a threshold speed, the longitudinal load moment control system is disabled.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a lift actuator, a lift valve arrangement, a tilt actuator, a tilt valve arrangement, and a tilt angle sensor configured to generate a first signal. The hydraulic system may further have at least one operator interface device movable to generate a second signal indicative of a desired lift velocity and a third signal indicative of desired tilt velocity, and a controller. The controller may be configured to command the lift valve arrangement to meter pressurized fluid based on the second signal, command the tilt valve arrangement to meter pressurized fluid based on the third signal and, when the first signal indicates that the actual tilt angle has entered a specified range of tilt angles during lifting, command the tilt valve arrangement to meter pressurized fluid based on the second signal as the actual tilt angle remains within the specified range.

Abstract: A detection link of a spill guard link mechanism is pivoted and connected to a bucket bracket in a position proximate to a bucket pivot support axis rotatably supporting a bucket and above a lower surface of a boom.

Abstract: An improved Z-bar linkage for wheel loader machines for maneuvering an implement such as a bucket or pallet forks may include lift arms pivotally connected between an end frame of the machine and the implement, a tilt link pivotally connected between the implement and a tilt lever that is pivotally connected between the tilt link and the lift arms. Lift cylinders may rotate the lift arms to raise and lower the implement, and a tilt cylinder may drive the tilt lever and tilt link to rotate the implement between a dump position and a racked position. Ratios of the lengths of these kinematic elements are provided such that the good performance with one implement, such as bucket, does not result in poor performance with another implement, such as the pallet forks.

Abstract: A backhoe loader 10 with a controller 100 that uses angular signals from at least one sensor to calculate a loader tool angle with respect to the vehicle frame 12 or with respect to the earth and to maintain the loader tool angle via controller generated commands to a tool actuator 61 as a function of the angular signals and commands to a boom actuator 50. The controller 100 enables proportional control of the tool angle via a command input device such as an electronic joystick 21. If the electronic joystick 21 is moved to an appropriate detent position, the controller executes a return to carry function. If the boom 31 is at or below the return to carry angle at the time the joystick 21 is moved to the detent position, the controller 100 executes a float function allowing the bucket 36 and the boom 31 to rest on the ground and follow the contours of the earth as the vehicle moves over the earth.

Abstract: A leveling control system and method for heavy equipment, in which a lower frame having a traveling unit and an upper frame are combined together by a tilting unit, includes a sensor unit, provided in the equipment, for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment, and detecting working state information of working devices; a control unit for receiving the twist angles, the traveling speed, and the working state information, calculating a correction angle for the leveling control of the upper frame, and generating a control signal for instructing an operation of an actuator in accordance with the correction angle; and a driving unit for performing the leveling through the actuator in accordance with the control signal received therein.

Abstract: A method for controlling a boom construction and a tool articulated thereto, the boom construction comprising a first boom and a first actuator controlling the same, a second boom articulated to the first boom, and a second actuator controlling the same, as well as a third actuator controlling the position of the tool, wherein in the method: the first actuator is controlled manually; and/or the second actuator is controlled manually and the third actuator is also controlled at the same time automatically to control the position of the tool. For example, the first actuator is controlled by use of a first set point; and/or the second actuator is controlled by use of a second set point; and in addition, the third actuator is controlled simultaneously by using for the control a variable dependent on at least one of said set points.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a lift actuator, a lift valve arrangement, a tilt actuator, a tilt valve arrangement, and a tilt angle sensor configured to generate a first signal. The hydraulic system may further have at least one operator interface device movable to generate a second signal indicative of a desired lift velocity and a third signal indicative of desired tilt velocity, and a controller. The controller may be configured to command the lift valve arrangement to meter pressurized fluid based on the second signal, command the tilt valve arrangement to meter pressurized fluid based on the third signal and, when the first signal indicates that the actual tilt angle has entered a specified range of tilt angles during lifting, command the tilt valve arrangement to meter pressurized fluid based on the second signal as the actual tilt angle remains within the specified range.

Abstract: A leveling control system and method for heavy equipment, in which a lower frame having a traveling unit and an upper frame are combined together by a tilting unit. The system includes a sensor unit, provided in the equipment, for measuring twist angles of the lower frame and the upper frame against a reference horizontal surface and a traveling speed of the equipment, and detecting working state information of working devices; a control unit for receiving the twist angles, the traveling speed, and the working state information, calculating a correction angle for the leveling control of the upper frame, and generating a control signal for instructing an operation of an actuator in accordance with the correction angle; and a driving unit for performing the leveling through the actuator in accordance with the control signal received therein.

Abstract: A backhoe loader 10 with a controller 100 that uses angular signals from at least one sensor to calculate a loader tool angle with respect to the vehicle frame 12 or with respect to the earth and to maintain the loader bucket angle via controller generated commands to a bucket actuator 60 as a function of the angular signals and commands to a boom actuator 60. The controller 100 enables proportional control of the tool angle via a command input device such as an electronic joystick 21. The controller 100 is capable of maintaining an inclination of the tool 36 with respect to the frame 12. If the boom 31 rises to an angle that is equal to or above a predetermined anti-spill boom angle the controller 100 drives the tool via commands to the tool actuator 60 to a tool angle that is equal to or less than a predetermined anti-spill bucket angle.

Abstract: A backhoe loader 10 with a controller 100 that uses angular signals from at least one sensor to calculate a loader tool angle with respect to the vehicle frame 12 or with respect to the earth and to maintain the loader tool angle via controller generated commands to a tool actuator 61 as a function of the angular signals and commands to a boom actuator 50. The controller 100 enables proportional control of the tool angle via a command input device such as an electronic joystick 21. If the electronic joystick 21 is moved to an appropriate detent position, the controller executes a return to carry function. If the boom 31 is at or below the return to carry angle at the time the joystick 21 is moved to the detent position, the controller 100 executes a float function allowing the bucket 36 and the boom 31 to rest on the ground and follow the contours of the earth as the vehicle moves over the earth.

Abstract: What is disclosed is a hydraulic control system for a mobile equipment, in particular for a wheel or backhoe loader, wherein a shovel is linked to a boom. The angular position of the shovel may be kept constant through the intermediary of an orientation control device during a pivoting movement of the boom relative to the axles of the equipment. In accordance with the invention, the orientation control device is realized such that in the event of a change of a pre-set angular position, a control signal is generated through a pilot control device, whereby a shovel control unit may be controlled in such a manner that the shovel is again returned into its predetermined angular position.

Abstract: A backhoe loader with a controller that uses angular signals from at least one sensor to calculate a loader tool angle with respect to the vehicle frame or with respect to the earth and to maintain the loader tool angle via controller generated commands to a tool actuator as a function of the angular signals and commands to a boom actuator. The controller enables proportional control of the tool angle via a command input device such as an electronic joystick. If the electronic joystick is moved to an appropriate detent position, the controller executes a return to carry function.

Abstract: A simple and compact loader having a sufficient strength with brackets fixed on a working vehicle. Lift arms are pivoted at one ends thereof to respective brackets so as to be vertically swung by respective lift arm cylinders. Attachments are vertically swingably supported on respective tip portions of the lift arms. Bucket links are connected to the respective attachments so as to transmit the telescopic action of bucket cylinders. Each of the bucket links is offset laterally from each of the lift arms. The middle portion of each of the lift arms is disposed above a straight line connecting both ends of the lift arm to each other, so as to ensure a space for arranging a steerable wheel under the lift arm.

Abstract: A system is provided for controlling the tilting of a load-carrying implement of a movable work machine that includes a frame and the implement, pivotally connected to the frame, and a tilting arrangement for tilting the implement in relation to the frame. The system includes a control for controlling the tilting of the implement based upon a sensor-registered movement of the movable work machine, and for controlling the tilting of the implement such that the implement counteracts the inertia of a load carried by the implement.

Abstract: In a multiple-switching valve having a bucket-leveling function, there are provided a diverged passage, which is diverged from a merged passage and connects with an unloading passage or a tank passage, and a switching valve to disconnect and connect the diverged passage. The switching valve allows a pressured oil drained from a rod-side chamber of a boom cylinder via a directional switching valve for boom to be supplied to the merged passage flow in the diverged passage, thereby preventing the pressure oil from being supplied to a head-side chamber of the bucket cylinder. Accordingly, the bucket-leveling function can be cancelled properly, thereby improving the operation of the multiple-directional switching valve.

Abstract: A wheeled vehicle includes a bottom chassis; a top chassis, which is coupled to the bottom chassis so that it is able to turn about a vertical axis; an operating arm coupled to the top chassis; an axle, which is coupled to the bottom chassis so that it can oscillate about a longitudinal axis of the vehicle; a plurality of wheels disposed on the axle; blocking means disposed between the bottom chassis and the axle for angularly blocking the axle about the longitudinal axis with respect to the bottom chassis; a circuit to activate the blocking means and inhibit oscillation of the axle about the longitudinal axis; and an angle sensor for supplying a signal indicative of the angular position of the operating arm about the vertical axis with respect to the bottom chassis.

Abstract: A load handling machine includes a body, a lifting arm pivotally mounted to the body about a first pivot axis, and a load handling implement pivotally mounted to the lifting arm about a second pivot axis. A first actuator provides movement about the first axis, and a second actuator provides movement about the second axis. A displacement device is mounted on the body and the lifting and includes a pair of cylinders. The second actuator and the displacement device are interconnected such that as the lifting arm is lowered, fluid ejected from one of the pair of cylinders of the displacement device is fed to an annulus side of the second actuator, and as the lifting arm is raised, fluid is ejected from annulus sides of both of the cylinders of the displacement device and is fed to a non-annulus side of the second actuator.

Abstract: There is provided a flow divider system in a hydraulic circuit for a work machine including a boom cylinder and a bucket cylinder. The flow divider system divides a pressured oil drained from a one-boom cylinder into an other-bucket cylinder and a tank via a first orifice, a second orifice and a flow dividing valve, maintaining a specified pressure difference between pressures downstream the first and second orifices. The first and second orifice are configured of a variable orifice respectively, and in the event that the oil flow from the one-boom chamber decreases, respective opening degrees of the first and second orifices are controlled so as to be reduced. Accordingly, changing of a divisional ratio of oil flow can be suppressed properly regardless of a small oil flow drained from the boom cylinder.

Abstract: In the operation of work machines of the type having an extensible arm, the maximum reach of the arm for a given work machine is limited by such factors as the vehicle's weight, body size and engine placement. The present invention provides for a work machine arrangement in which a work machine has an engine cooling apparatus mounted to the work machine body such that the engine cooling apparatus's longitudinal axis is oriented substantially parallel to the arm longitudinal axis.

Abstract: An overshot loader including a set of ground engaging members, a frame attached to the set of ground engaging members, and a linkage assembly movably connected to the frame and located within a longitudinal center portion of the frame.

Abstract: The present invention relates to a wheeled shovel loader that comprises a boom (3) capable of pivoting about an axis (4) as well as loading shovel (13) that can be actuated by a tilting structure (11, 12). According to this invention, at least one additional arm (7) connecting the boom (3) and the loading shovel (13) is hinged so as to be capable of displacement in the same way as a parallel linkage or parallelogram on said arm (3) under the action of at least a first connecting rod (8) and at least a second connecting rod (9). The shovel loader of the present invention comprises means for controlling the displacement of the additional arm (7) according to the angular position of the boom (3) relative to its pivot axis (4), as well as means for maintaining the loading shovel (13) in a horizontal position.

Abstract: The present invention concerns a lift truck comprising a mobile frame (1), a tiltable boom (3) provided upon it and tilting means (7) for tilting said boom (3), whereby the boom (3) is fixed to the frame (1) in a tilting manner by means of a support (5) which can be moved in relation to the frame (1) in the longitudinal direction of this frame (1), and whereby the lift truck contains displacement means (8) for moving this support (5) which are coupled to the tilting means (7) for the boom (3), such that these tilting means (7) and the displacement means (8) simultaneously tilt the boom (3) together and move the support (5) of the boom (3) in such a manner that the front end of the boom (3) follows a path which is practically perpendicular to the above-mentioned longitudinal direction of the frame (1).

Abstract: A vertical lift type arm device includes a set of left and right control links each having three connection shaft holes, a set of left and right central mounting parts which are provided at a center part of the main frame, and a set of left and right mounting parts which are provided at rear parts of the lift arms and extend downward. Front end parts of the control links and the central mounting parts are pivotably attached to each other, center parts of the control links and lower end parts of the mounting parts are pivotably attached to each other, and connection axes of the control links and the central mounting parts are provided at a same height as or at a higher position than connection axes of lower end parts of the rear links and the main frame.

Abstract: The invention comprises a backhoe with a tool pivotally attached to a dipperstick, an actuator for controllably moving the tool about its pivot, and an angular velocity sensor for sensing the angular velocity of the tool relative to an earth based coordinate system. A controller is adapted to perform a tool auto-hold function, automatically maintaining an initial tool orientation by processing the angular velocity data and commanding movement of the tool actuator to hold the angular velocity at zero. The controller is adapted to discontinue the tool auto-hold function when the operator manipulates a tool command input device affecting tool actuator movement, and resume the tool auto-hold function at the new orientation affected by the operator. Manipulation of an auto-hold command input device allows the operator to selectively enable and disable the tool auto-hold function.

Abstract: A high versatility can be obtained, the pipe laying can be configured easily and, by virtue of the fact that a pilot pressured oil is managed, a hydraulic apparatus can be compacted. A differential pressure &Dgr;P between a pressure of the pressured oil on an upstream side and a pressure of the pressured oil on a downward side of operation valves is set to a certain value by a front-to-rear differential pressure stabilizer. As a result, flow rates Q1, Q2 of the operation valves are determined univocally in accordance with opening surface areas (opening amounts) A1, A2 of the operation valves, irrespective of load fluctuations, that is to say, a fluctuation of &Dgr;P. When one of operation members are operated, the opening amount A2 of the other operation valve correspondent with the other operation member is changed in accordance with an operation amount S1 of that operation member, and the other hydraulic actuator correspondent with the other operation valve is driven.

Abstract: A method and apparatus for lifting a work implement attached to a work machine. The method and apparatus includes delivering a lift command to a hydraulic lift circuit, diverting a portion of the lift command to a hydraulic tilt circuit, and responsively tilting the work implement to a rack-back position in cooperation with lifting the work implement.

Abstract: A linkage assembly for connecting an implement to a frame of a work machine which provides greater visibility for an operator of the work machine is disclosed. The linkage assembly includes a box-boom lift arm having a frame end portion and an implement end portion, wherein (i) the frame end portion is pivotally coupled to the frame, (ii) the implement end portion is pivotally coupled to the implement, and (iii) the frame end portion includes a first extension and a second extension spaced apart from each other so as to define a first lever space therebetween. The linkage assembly also includes a lift cylinder having a frame end and a lift arm end, wherein (i) the frame end is pivotally coupled to the frame, and (ii) the lift arm end is pivotally coupled to the box boom lift arm. Moreover, the linkage assembly includes a rear tilt link having a first end and a second end, wherein the first end is pivotally coupled to the frame.

Abstract: A high-lift lateral dump system for pavement/street sweepers (20) includes a debris container (30) positioned between laterally adjacent lift assemblies (40R, 40F), each lift assembly (40R, 40F) including a vertically extending upright (42), a lift arm (44) that is pivoted at one end to upper end of the upright (42), and a single-ended double-acting hydraulic lift cylinder (46) that functions to raise and lower the lift arm (44). A torque control mechanism (48) minimizes mis-phasing between the lift cylinders (46) of each lift assembly (40R, 40F), and a manual safety stop mechanism (50) allows an operator to selectively lock the debris container (30) and the related structural components in the lifted position. An attitude-control system uses hydraulic fluid from the rod end (46r) of the lift cylinder (46) to maintain the debris container (30) in a horizontal or near horizontal attitude during the lift cycle.

Abstract: A loader linkage having a bucket and boom arm mounted to the loader vehicle by way of top and bottom links, the top link being pivotally coupled with a structural member of the vehicle that extends upwardly from the vehicle frame generally at the rear of or behind the operator station. The top link is coupled to the structural member at a point generally above and behind the operator seated on the vehicle. The linkage establishes a bucket path that extends generally vertically initially and that then extends forwardly through the entire range of upper motion of the bucket. The linkage causes the bucket to achieve maximum reach at the bucket's maximum height. The orientation of the top link also reduces the vehicles tendency to tilt rearwardly onto the rear wheel's during leveling operations.

Abstract: A lift assembly for lifting an implement relative to a frame of a work machine is disclosed. The lift assembly includes a lift arm having a frame pin bore, a cylinder pin bore, a linkage pin bore, and an implement pin bore. The frame pin bore and said cylinder pin bore define a first line. The frame pin bore and said implement pin bore define a second line. The second line is located above said first line. The first line and said second line define an angle which is greater than three degrees. A plane intersects said first line at a center point of said cylinder pin bore and is normal to said first line. A said plane divides said lift arm into a frame-side segment and an implement-side segment. The first line includes a first segment which is entirely coincident with said implement-side segment of said lift arm. The linkage pin bore is defined in said frame-side segment. The lift assembly further includes a tilt lever which is pivotably coupled to the lift arm at said linkage pin bore.

Abstract: A front end loader assembly that is attachable to a truck not otherwise intended to use a front end loader. The front end loader assembly includes a stationary mount that attaches to the chassis of the vehicle. A frame structure is provided having a pair of generally vertical frame elements and at least one generally horizontal frame element. The frame structure is pivotably coupled to the stationary mount at a first point of attachment. A single first hydraulic cylinder extending between the stationary mount and the frame structure, wherein the first hydraulic cylinder is capable of moving the frame structure relative the stationary mount about the first point of attachment. An arm structure is coupled to the frame structure by a hinged connection. A single second hydraulic cylinder extends between the frame structure and the arm structure, wherein the second hydraulic cylinder is capable of moving the arm structure relative the frame assembly. A bucket is coupled to the arm structure.

Abstract: An apparatus for controlling movement of an implement relative to a frame of a work machine is disclosed. The apparatus includes a lift arm having an implement, such as a bucket, pivotally coupled thereto. The apparatus also includes a pivot bar which is pivotally coupled to the lift arm via a coupling pin. A first hydraulic cylinder is coupled to the pivot bar. A second hydraulic cylinder is also coupled to the coupling pin. The first hydraulic cylinder and the second hydraulic cylinder are both actuated so as to lift the lift arm. Moreover, the first cylinder is actuated so as to tilt the bucket. A number of position sensors are provided to communicate output signals indicative of the position of the lift arm and the bucket to a controller. The controller processes such output signals and thereafter alters the position of a pair of proportional fluid valves associated with the first and second hydraulic cylinders.

Abstract: A method is disclosed for controlling the cutting depth and angle of an excavator bucket to excavate a surface to a desired contour. The method includes the steps of: (1) inputting data to a machine control system to define a desired contour of the excavated surface; (2) positioning the excavator bucket close to the desired contour; (3) enabling automatic control; and (4) automatically controlling movement of the excavator bucket only when the position of the excavator bucket is within a predetermined distance or angle of the desired contour. The method is used to automatically control the excavation to a desired depth if the bucket is within a predetermined distance of a desired depth. The method is also used to automatically control the angular orientation of bucket if the slope of the bucket is within a predetermined angle of a desired slope.

Abstract: A blade control system for a bulldozer, comprising: (a) a pitch angle detector for detecting a pitch angle of a vehicle body when the vehicle body inclines back and forth; (b) an actual tractive force detector for detecting an actual tractive force of the vehicle body; and (c) a controller for correcting the actual tractive force detected by the actual tractive force detector according to the pitch angle detected by the pitch angle detector and for controlling the blade to be lifted or lowered such that the corrected actual tractive force becomes equal to a target tractive force.

Abstract: A tilt linkage mechanism for controlling the pitch of an implement used with load elevating vehicles which includes an actuation cylinder which is mounted intermediate to the length of the implement lift arms and which is utilized to control the rotation of at least one pivot shaft connected to the vehicle lift arms so as to be in parallel relationship between a first pivot axis where the lift arms are connected to the vehicle and a second pivot axis where the lift arms are pivotally connected relative to the implement. At least one parallel linkage assembly is connected to the at least one pivot shaft and to pivot points spaced on either side of the second pivot axis and stabilizer elements are provided for allowing rotation of the actuation cylinder during use for adjusting the pitch of the implement.

Abstract: The hydraulic circuit of the invention includes first and second directional control valves 13, 15, each shiftable between three positions. Hydraulic circuit extending from the second directional control valve 15 and a second cylinder 7 to a first cylinder 11 is so configured that, when the second directional control valve 15 is shifted to the first position, with the first directional control valve 13 being assigned to the N-position, hydraulic oil from the second cylinder 7 is directed to the first cylinder 11, so as to cause the attachment 9 to be tilted in the forward direction, and when the second directional control valve 15 is shifted to the second position, hydraulic oil expelled from the second cylinder 7 is directed to the first cylinder 11, so as to cause the attachment 9 to be tilted in the rearward direction.

Abstract: A lift boom assembly including a pair of laterally spaced interconnected lift arms having a tool mounted between forward ends thereof. Each lift arm includes a main lift link having upper and lower connecting portions at a rear end thereof. A second lift link is pivotally connected to the upper connecting portion of the main lift link and partially controls movements of the respective lift arm. The opposite end of each second lift link is pivotally connected to a frame of a machine on which the lift assembly is mounted. Movement of the lift arms is further controlled by a pair of control arms. A lower end of each control arm is pivotally connected to the frame. When the boom assembly is in a lowered position relative to the frame, a second or upper end of each control arm extends upwardly and rearwardly from the lower end and is pivotally connected to the lower connecting portion of the respective main lift link.

Abstract: An anti-rollback mechanism is provided for an off-highway implement having a mobile frame and a loader mechanism including a bucket pivotally attached between lift arms of the loader mechanism. The lift arms are connected to the frame of the implement and lift actuators are used to angularly move the lift arms to elevationally position the bucket. Tilt actuators connected to the bucket and to the lift arms effect rolling movements of the bucket relative to the lift arms. A single handled control mechanism regulates operation of the tilt and lift actuators through hydraulic tilt and lift valves. The anti-rollback mechanism of the present invention automatically positions the tilt valve as the lift arms move through a predetermined range of angular movements relative to the frame to prevent rollback of the bucket past a generally level position as the lift arms and bucket are elevated.