Abstract: A forklift truck includes a carriage that moves up and down by a mast assembly in a multi-stage structure including an outer mast, a first inner mast accommodated in the outer mast, and a second inner mast accommodated in the first inner mast. The forklift truck includes a first lift cylinder configured to move the first inner mast up and down; a second lift cylinder configured to move the second inner mast up and down and having a pressure reception area less than a pressure reception area of the first lift cylinder. A first lift hydraulic line supplies hydraulic oil to the first lift cylinder. A second lift hydraulic line supplies hydraulic oil to the second lift cylinder. A pressure regulating valve is provided to increase a pressure of the hydraulic oil to a pressure capable of driving the second lift cylinder.

Abstract: The invention relates to a method (100) of operating an actuator arrangement including at least two types of actuators (6, 7, 11, 12, 30, 34) effectuating different types of movement of a connected device (10, 32) to be actuated, where a change of attitude of the connected device (10, 32) has an influence on the position of at least a defined part (13, 14) of the connected device (10, 32). Different types of actuators (6, 7, 11, 12, 30, 34) are actuated in an automated way to at least partly compensate for the change of position of the defined part (13, 14) of the connected device (10, 32) when changing the attitude of the connected device (10, 32), at least for a certain range of movements.

Abstract: An autonomous mobile device has a main body and an extensible mast to raise and lower a payload, such as a camera, relative to the main body. The mast may comprise a set of telescoping sections, with each section comprising two or more pieces that are joined during assembly. A motor moves a flexible rack between a first spool and the mast to raise or lower the mast. For example, during extension a motor-driven pinion engages teeth on the flexible rack, pulling the rack from the first spool and pushing up the mast. A cable stored on a second spool may be extended and retracted with the flexible rack. The cable transfers one or more of data or power between the main body and the payload. A sensor may be used to detect features on the flexible rack to provide data about how far the flexible rack has been extended.

Abstract: A nacelle-mountable lift system for mounting and dismounting a rotor blade of a wind turbine involves a jib crane, the jib crane having a base removably mountable on a nacelle of the wind turbine and a jib mounted on the base. The jib has a boom arm supported on the base by at least one support strut extending between the base and the boom arm. A winch is mounted on the boom arm. At least two sheaves are rotatably mounted on the boom arm. A holder is connectable to the blade. At least two lift cables pass over the at least two sheaves connecting the holder to the winch. The boom arm is positionable to position the holder beyond a rotor hub of the wind turbine when the crane is mounted on the nacelle.

Abstract: The device comprises a folding handling arm, equipped with a handling head and at least two successive arm parts, in which the arm parts are connected to each other by a folding fastening, the device further comprising a suspension structure (HS) to suspend the handling arm for the purpose of supporting it, the device further comprising a rotating structure to turn the handling arm by turning the suspension structure in relation to the support frame located at the upper part of the cargo space in the device. The suspension structure of the handling arm is essentially a rotationally symmetrical, rotation ring structure disc that is rotatable in relation to its support frame with the rotating structure in order to suspend the handling arm for the purpose of supporting it.

Abstract: A portable hoist apparatus includes a boom secured to a frame or body, which includes, at a side opposite the boom, a cylindrical mounting collar, on a vertical axis, can be slipped over a cylindrical pivot tube that in turn is connected to any of a number of different base mounting structures that are configured to be attached to various stable anchoring structures, such as on buildings, decks, posts, vehicles, floors and many other structures.

Abstract: A Crane boom segment is provided for assembly of a crane boom by interconnection of multiple crane boom segments from a transport configuration to an operational configuration. The crane boom segment includes a first and second planar latticed truss, each with two chords between which permanent lacing elements extend. Both chords of each planar latticed truss include segment connection parts at their head ends allowing crane boom segments to be connected to each other in series, and in the operational configuration the first and second planar latticed trusses are provided at opposite sides of the longitudinal axis of the crane boom segment. A crane boom segment further includes a first and second lattice web, each lattice web connectable to one of the chords of the first planar latticed truss and one of the chords of the second planar latticed truss.

Abstract: A boom-extending wire locking structure has a wire locking tool, provided at a base end side of a first boom member and/or a base end side of a third boom member, that locks an extending wire by winding a lock part of each wire member. The wire locking tool includes: a pair of fixing pieces provided on both sides in an orthogonal direction orthogonal to a boom-extending direction and fixed to the first boom member and/or the third boom member; and wire locking parts, provided between the pair of fixing pieces, including arch-shaped grooves for winding the respective lock parts of the wire members. The wire locking parts are arranged in a central axis direction of the arc shape between the pair of fixing pieces. Central axes of the wire locking parts are arranged at different positions in the orthogonal direction from respective adjacent wire locking parts.

Abstract: A system for coupling a user to a support apparatus includes a harness for the user, a hoist, and frame. The harness and the hoist have co-operable attachment means for releasably coupling the harness to the hoist. The frame is configured to receive the user, where the harness and the frame have co-operable attachment means for releasably coupling the harness to the frame.

Abstract: The telescopic arm for operating machines includes an outer arm, four coaxial slip-off elements, first, second, third, fourth and an operative head associated to the latter. The telescopic arm includes: a drive system, supported partially outside of the telescopic arm, for moving synchronously said slip-off members in their extending and returning travels; a hydraulic circuit, housed inside said telescopic arm, comprising a first and a second group of hydraulic conduits, which include, respectively, first and second flexible pipes, kept stretched during the returning step of said slip-off members by the corresponding idler pulleys, supported by the latter.

Abstract: A fall protection apparatus includes a heavy support base with a pivotal mast having a top member for rotation around the axis of the mast carrying a series of booms pivotal about respective vertical axes, each having an end coupling member for receiving a fall restraint harness. Each boom is formed by a tube which fractures on a fall and an elongate stainless steel strap inside the tube which bends without fracturing. The mast includes a series of telescopic rectangular mast sections with a winch driven cable and pulley arrangement for extending the first section which acts to pull the second inner section to the extended position as the first inner section moves out of the outer section. Each section includes first and second pulleys mounted at the same face of the section with the cable located between the face of the section and the face of the next section.

Abstract: A hydraulically actuatable jib for a loading crane includes at least two jib extensions, the first jib extension being designed as an outer jib extension and the second jib extension being designed as an inner jib extension. At least two feed cylinders extend and react the at least two jib extensions. A hydraulic circuit for a working fluid includes a retraction line for retracting the feed cylinders in a pressurized manner, and the retraction line opens into the feed cylinder of the outer jib extension. A tank is provided for releasing the working fluid, and a control valve can be switched into an open position when the outer jib extension reaches a defined retraction position, particularly when the outer jib extension is substantially fully retracted. The valve thereby supplies the feed cylinder of the inner jib extension with pressurized working fluid.

Abstract: A boom structure (2) on a work machine (1) including at least two boom branches (2a, 2b) and a main boom structure (2c) extending from their convergence area (4) substantially in a working direction. Thus the boom structure (2) provides a fork-like structure.

Abstract: An industrial machine includes a frame, an elongated member, an attachment, a plurality of fluid lines, and a cartridge. The frame includes a boom and a fluid source. The elongated member is movably coupled to the boom and includes a first end and a second end. The attachment is pivotably coupled to the first end of the elongated member. The plurality of fluid lines is coupled to the second end of the elongated member and is in fluid communication with the fluid source. The cartridge is removably coupled to the elongated member. The cartridge includes a housing and a plurality of conduits supported within the housing. The conduits are in fluid communication with the plurality of lines.

Abstract: A telescopic boom extending along a longitudinal axis includes a base section intended to be connected to a frame of a machine for lifting loads, a plurality of movable sections, a hydraulic cylinder connecting the base section to a first movable section of said plurality for extending the first movable section relative to the base section, at least one extension chain between the base section and a second movable section for extending the second movable section relative to the first movable section, at least one further extension chain interposed between the first movable section and a third movable section for extending the third movable section relative to the second movable section, the extension chain and the further extension chain located at opposite sides of the longitudinal axis.

Abstract: A dual crane apparatus and a method of use are disclosed herein. The disclosed dual crane apparatus generally comprises a support frame and two rotating crane members mounted to the support frame, wherein the crane members can each independently move up and down in a vertical direction, extend and retract in a horizontal direction, and rotate clockwise and counterclockwise. The disclosed dual crane apparatus can be utilized for servicing mobile irrigation systems.

Abstract: A telescopic boom broadly comprises an elongated hollow outer boom, an elongated inner boom telescopically received within the outer boom, and a guidance structure for guiding the inner boom for telescopic movement is provided. The guidance structure includes a plurality of guide rails attached to the interior corners of the outer boom, a first roller assembly attached to one end of the inner boom, a second roller assembly attached to one end of the outer boom, and a mid roller assembly positioned proximal to the second roller assembly. The first roller assembly includes a plurality of wheels mounted on axles for engaging the guide rails. The second roller assembly includes roller bars positioned on opposed sides of one end of the outer boom for guiding the inner boom during telescopic movement. The mid roller assembly includes a third roller bar that engages guide rails positioned on the inner boom.

Abstract: A telescopic boom broadly comprises an elongated hollow outer boom, an elongated inner boom telescopically received within the outer boom, and a guidance structure for guiding the inner boom for telescopic movement is provided. The guidance structure includes a plurality of guide rails attached to the interior corners of the outer boom, a first roller assembly attached to one end of the inner boom, a second roller assembly attached to one end of the outer boom, and a mid roller assembly positioned proximal to the second roller assembly. The first roller assembly includes a plurality of wheels mounted on axles for engaging the guide rails. The second roller assembly includes a pair of roller bars positioned on opposed sides of one end of the outer boom for guiding the inner boom during telescopic movement. The mid roller assembly includes a third roller bar that engages guide rails positioned on the inner boom.

Abstract: A backstay spreader attachable between a pair of backstay sections on a crane includes first and second members each having a backstay section connector at a first end and a pivoting joint connector at a second end, the pivoting joint connectors being used to hold the first and second members together with a pivotal connection and each having an extending portion extending away from the pivotal connection, with an angle between the extending portions. The backstay spreader also includes an actuator mounted between the pivoting joint connectors. The actuator controls the angle between the extending portions of the two pivoting joint connectors, which defines an angle between the first and second members.

Abstract: An apparatus and method for handling pipe includes an elongate frame structure for mounting on a ground surface, in which a carriage unit is mounted on the frame structure and is operable for selective and reciprocal shifting along the frame structure. A boom member mounted on the carriage unit is operable for selected pivotal movement relative to the carriage unit, and a plane generally parallel to the boom member's longitudinal axis, about a generally horizontal pivot axis oriented transverse to the direction of shifting of the carriage unit along the frame structure. An elongate pipe carrier mounted on the boom member as dimensioned for receiving pipe so that the pipe's longitudinal axis is substantially parallel to the longitudinal axis of the boom member and the pipe member, wherein the pipe carrier is operable for selective pivotal movement about its longitudinal axis.

Abstract: An upper frame for construction equipment mounted to swing on a lower driving structure is provided, in which fixing pins for supporting a boom and a boom cylinder are coupled to left and right side plates that are welded on a base plate to face each other, and a plate-shaped joint connection plate is welded on the left and right side plates and the base plate, so as to support the left and right side plates by exhibiting the rigidity and flexibility against load being transferred to the fixing pins through a working device during working.

Abstract: A slat replacement machine having an elongated rectangular frame supported at each end by a tracked drive unit which provides zero turn capability to the machine. A pair of outrigger assemblies is provided at the forward end of the frame and a pair of outrigger assemblies is provided at the rearward side of the frame. The outrigger assemblies may be pivotally moved from a stowed position adjacent the frame to an outwardly extending position. A telescopic boom is pivotally mounted on the upper end of a rotatable pedestal which extends upwardly from the center of the frame. Various components of the machine such as hydraulic cylinders and hydraulic motors are radio controlled.

Abstract: The present disclosure relates to a mobile crane comprising a superstructure having a revolving deck and at which a preferably telescopic boom is pivotably arranged around a pivot point, with a winch being additionally present for the hoist rope. In accordance with the present disclosure, the winch is arranged beneath the pivot point of the telescopic boom in the revolving deck.

Abstract: In a self-traveling working machine such as a crane, a working attachment such as a boom is arranged to transversely extend below an operator's cabin in such a manner that part of the cabin overlaps the attachment, it being arranged that during crane operation, the cabin is moved widthwise outside the working machine to avoid interference with the boom.

Abstract: A mobile cellular telephone tower comprises a self-propelled base and a tower connected to the base. The tower includes a base segment and at least a first extendable segment operatively connected to a second extendable segment. A winch is connected to the base, and a first cable is connected between the base segment and the first extendable segment to extend the first extendable segment. A second cable is connected between the winch and the second extendable segment to retract the second extendable segment. Cellular telephone network testing equipment mounted on the tower.

Abstract: In a self-traveling working machine such as a crane, a working attachment such as a boom is arranged to transversely extend below an operator's cabin in such a manner that part of the cabin overlaps the attachment, it being arranged that during crane operation, the cabin is moved widthwise outside the working machine to avoid interference with the boom.

Abstract: A mobile crane includes an under carriage, a superstructure that is rotatably mounted on the superstructure, and a main boom, which is composed of a base body and several telescopic lengths up to a predetermined maximum number, which slide into one another and can be extended from the base body. The main boom is mounted on the superstructure so that it can rotate about a horizontal axis and its inclination can be adjusted by means of a hydraulic tilting cylinder that is hinged on the superstructure and the base body. A maximum permissible weight is predefined for the main boom, as a result of a restriction on the permissible axle load of the mobile crane during road haulage. The crane is also provided with a lifting capacity increasing device, which significantly increases the lifting capacity of the main boom when the telescopic lengths are extended, in relation to the state without the lifting capacity increasing device.

Abstract: A telescopic crane, includes a substructure, a superstructure rotatably mounted onto the substructure, a counterweight and a telescoping boom structure which includes a main boom slewable about a luffing plane. The main boom has a boom base and at least one telescope section received in the boom base and displaceable between retracted and extended positions. At least one guy support is mounted to the boom structure and connected to a guy rope which extends substantially longitudinally in the direction of the boom structure. The guy support is oriented with respect to the luffing plane at an inclination which is so selected that a lateral load acting on the boom structure is partially or entirely received by the guying.

Abstract: A trailer-mounted crane apparatus includes a trailer supported from a ground surface on at least two wheels. A hydraulically operated crane arm is mounted to the trailer and is extendable outwardly. A crane hydraulic power unit is mounted to the trailer and supplies pressurized hydraulic fluid to the crane arm. A vibrational sheet piling driver can be supported by the crane arm. A vibrational hydraulic power unit for supplying power to the driver is mounted on the trailer. A control panel for the crane hydraulic power unit and the vibrational driver hydraulic power unit, and an associated operator's seat, are also mounted on the trailer. The crane apparatus includes wide tires for reducing the surface pressure under the apparatus. This allows the apparatus to be transported across and used on delicate surfaces such as golf course greens and other groomed surfaces.

Abstract: A trailer-mounted crane apparatus includes a trailer supported from a ground surface on at least two wheels. A hydraulically operated crane arm is mounted to the trailer and is extendable outwardly. A crane hydraulic power unit is mounted to the trailer and supplies pressurized hydraulic fluid to the crane arm. A vibrational sheet piling driver can be supported by the crane arm. A vibrational hydraulic power unit for supplying power to the driver is mounted on the trailer. A control panel for the crane hydraulic power unit and the vibrational driver hydraulic power unit, and an associated operator's seat, are also mounted on the trailer. The crane apparatus includes wide tires for reducing the surface pressure under the apparatus. This allows the apparatus to be transported across and used on delicate surfaces such as golf course greens and other groomed surfaces.

Abstract: A telescopic boom (1) for a vehicle (25) or a hoist with a storage rack (6) for at least two box girders (2, 3) guided displaceably in one another in the direction of their longitudinal axes, which are mounted to pivot about a horizontal pivot axle (5) in the storage rack (6) and which can be displaced reciprocally by means of a servo-drive (19) is described. In order to create advantageous structural conditions it is proposed that the longitudinal axles of the box girders (2, 3) form an upwards arched arc of a circle (4) which runs concentrically to a common axis parallel to the pivot axis (5).

Abstract: A loader includes a base equipped with a turning device, for attaching the loader to a carrier machine, a telescopic main boom including a frame pivoted on the base, and a telescopic component arranged to move linearly in relation to it and pivoted on the base, a hinged boom pivoted on the main boom, a lifting cylinder pivoted at its first end to the base and at its second end directly or indirectly to the main boom to operate it, an arm directly or indirectly attached to the hinged boom, pivoted to the main boom, a maneuvering cylinder disposed about the main boom between the frame and the telescopic component, the telescopic component is pivoted to the arm operating the hinged boom by the first pivot, the loader includes a link rod pivoted at one end to the frame of the main boom and at the other end to the second pivot of the said arm, which is at a distance from the said first pivot.

Abstract: The present invention provides a construction machine in which a plurality of winches are arranged to be overlapped vertically at a rear part of an upper rotating body. Therefore, a space that the winches occupy is reduced, so that the space of the upper rotating body can be utilized effectively, and a radius of rotating rear end can be reduced.

Abstract: A combined locomotive and crane construction (10) including a locomotive unit (11) having an elongated undercarriage member (21) provided with a front section (22) and a rear section (23) wherein the front section (22) provides a support platform for a locomotive engine (20) and a control cab (25) and the rear section (23) provides a support platform for a crane unit (12) having an extensible crane boom (34) that is rotatably disposed over the rear section 23 of the undercarriage member (21).

Abstract: A self propelled transportable lift truck (A) having a frame (1) formed by two spaced parallel longitudinal front members and a rear transverse member, at least two front wheels (5, 6) and at least one steerable rear wheel (7), such that the lifting mechanism thereby extends from a most retracted position between the longitudinal members of the frame. The lifting mechanism to raise and/or lower the lifting tines comprises a telescopic lifting arm (4) articulated about a horizontal axis perpendicular to the longitudinal axis of the lift truck. An operator's cab (2) is located to one side of the lifting mechanism; the motive drive unit (3) is housed beneath the lifting mechanism. The lifting mechanism is provided with a yaw control to facilitate the lateral movement of the lifting lines. In addition, the yaw control has, on demand, the capability to automatically self centre the lifting mechanism.

Abstract: A telescopic crane, includes a substructure, a superstructure rotatably mounted onto the substructure, a counterweight and a telescoping boom structure which includes a main boom slewable about a luffing plane. The main boom has a boom base and at least one telescope section received in the boom base and displaceable between retracted and extended positions. At least one guy support is mounted to the boom structure and connected to a guy rope which extends substantially longitudinally in the direction of the boom structure. The guy support is oriented with respect to the luffing plane at an inclination which is so selected that a lateral load acting on the boom structure is partially or entirely received by the guying.

Abstract: An inverted pedestal crane has a base mountable to an underside of a horizontal support structure, such as for example a rig floor. A crane pedestal extends downwardly from the base, and a boom connects pivotally to the pedestal. The pedestal and the crane base rotate about a vertical axis, while the boom moves pivotally in relation to the pedestal. The crane has one main and a pair of auxiliary hydraulic rams for moving the boom during load handling operations. A robust slew bearing assembly mounted above the crane pedestal allows rotation of the base and the pedestal. The slew bearing assembly has a pair of parallel plates, a plurality of centering rollers and a plurality of stabilizing rollers mounted adjacent to an outer circumference of the parallel plates, between the plates. A winch assembly is mounted on top of the base, the winch assembly carrying a cable that extends over a pulley secured to a free end of the boom.

Abstract: A telescoping boom crane having a multi-sectioned, telescopically extending boom and an extensible pendant support system. The extending boom includes boom sections that are extensibly receivable within the adjacent boom section. The boom sections are made of a sheet material. A releasable locking mechanism may be attached to the boom sections to secure the boom sections. The extensible pendant support system includes a plurality of pendants. The pendants are extensibly receivable within an adjacent pendant. The pendant support system at least partially supports the boom when a load is applied to the boom. Further, the support system may include a forestay length locking device functioning to prohibit extension of a subsequent pendant from an adjacent pendant once the former pendant achieves an extended position.

Abstract: A tire manipulator for mine service vehicles has a mast for mounting on a vehicle, a telescopic boom connected to said mast and wheel handling equipment connected to said telescopic boom. A first boom may connect said mast to a moveable boom, the moveable boom being connected to said telescopic boom.

Abstract: A delimber having a standard carriage and a delimbing boom, the delimbing boom slidably mounted through the carriage. A drive module is detachably connected to the carriage for use in moving the boom relative to the carriage. Two different types of booms and up to three different drive modules, each with a different drive, can be provided. The boom and module selected to give the operating characteristics desired by the operator are connected to the carriage. Drive transfer members, in the form of cable or chain drives, are connected between the selected drive module and the selected boom. The module carries a variable displacement hydraulic motor. The motor is connected by a gear box to the drive transfer member. On delimbers using cable drives, at least one end of each cable is connected to the delimber with a hydraulic tensioner.

Abstract: A crane vehicle comprising a telescopic main boom which can be hydraulically configured by means of an assembly comprising a plunger cylinder and to which a derrick mast can be secured is provided with a plunger cylinder configured as a supply and discharge line for hydraulic fluid so that it can be used for conveying hydraulic fluid into a telescopic derrick mast which is mounted on the telescopic boom. Furthermore, a derrick cylinder which can be secured to the main boom is provided for hydraulically adjusting the inclination of the telescopic derrick mast.

Abstract: A telescoping boom crane having a multi-sectioned, telescopically extending boom and an extensible pendant support system. The extending boom includes boom sections that are extensibly receivable within the adjacent boom section. The boom sections are made of a sheet material. A releasable locking mechanism may be attached to the boom sections to secure the boom sections.

Abstract: A method of constructing a five section telescoping aerial lift, crane or similar vehicle-mounted equipment and a lift constructed in accordance with the method having one end pivotally secured, about a horizontal axis, to the pedestal and the other end of the telescoping boom is equipped with a sheave for rigging the turret winch lift-line and/or it is equipped with a platform assembly for positioning workers, tools, or other devices at high positions, the four telescoping boom sections being extended and retracted individually by means of one hydraulic actuator for each moving section, two actuators located in the interior of the boom sections and two actuators located on the exterior of the boom sections.

Abstract: A mobile crane including an inclinable telescopic jib having a base case, a plurality of telescoping segments which can be extended and retracted, at least an inner-most one of the telescoping segments being pivotable in a direction of the inclinable jib and connected to a non-bending one of the segments by a hinge which forms a bending point which can be closed and opened, the hinge of the bending point being arranged on the underside of the jib, and an adjusting device arranged on a topside of the jib for opening and closing the bending point.

Abstract: The invention provides a drive system for extending or retracting a boom. The boom comprises an elongated boom slidably mounted to a vehicle. The drive system comprises: a flat belt extending generally parallel to the boom; a rotatable drum mounted to the vehicle; and a pair of spaced apart rollers adjacent the rotatable drum. The belt is attached to the boom by couplings at either end of the belt. A loop of the belt extends through a gap between the pair of spaced apart rollers and around an outer circumference of the rotatable drum. The gap has a width less than a diameter of the rotatable drum. The drive system can be used to advantage in a forestry machine such as a tree delimber.

Abstract: A crane structure for hoisting, holding and/or towing heavy loads is provided. The crane structure includes a frame, for example a wrecker truck chassis, a boom support assembly, and a pair of booms each having a first member pivotally mounted to the boom support assembly so that the first boom and the second boom are pivotal in parallel vertical planes. Each of the first boom and the second boom also has a fluid operable second member slidably received by the first member. A control system is in operative communication with the first boom, the second boom and a winch assembly to independently activate each second member to extend from and retract to its corresponding first member, to pivotally position each boom with respect to the frame, and to activate the winch assembly to retract and extend cables about free ends of the respective second members.

Abstract: A crane, in particular railbound mobile crane, with a luffing jib telescoping at both sides which can be swung up and down as well as raised and lowered with its base boom. The boom is supported in its end regions at the vehicle on a swivel bearing which can be raised and lowered. The luffing jib is swivelable about vertical axes in the region of the swivel bearings. For this purpose, every swivel bearing is supported at one of two separate multiple-axle traveling mechanisms so as to be displaceable traverse to the longitudinal axis of the mobile crane. The two traveling mechanisms are coupled with one another via the base boom of the luffing jib, which base boom is connected with the swivel bearings.

Abstract: In the present invention, there is provided a mobile crane for hoisting movable articles and for being towed to and from an article hoisting site behind a pickup truck having a hitch attachment. The mobile crane comprises a frame having a front end, a rear end, a pair of front wheels and a pair of rear wheels. The mobile crane also has a mast extending vertically from the frame and a boom support bracket affixed to the mast. A telescopic boom having a far end and a near end is movably cantilevered in the boom support bracket. A tow bar is removably connected to the far end of the boom. The tow bar has a hook-up member mounted thereon and is connectable to the hitch attachment of the pickup truck. A double-acting hydraulic cylinder is connected between the boom support bracket and the boom for raising the front wheels off the ground when the hook-up member is connected to the hitch attachment.

Abstract: A proportionally extendable multi section boom crane is provided with an automatically erectable mast pivotally carried by one of the boom sections. The mast, which has a secondary sheave on the outer end thereof, normally rests in a stowed position adjacent the boom section on which it is mounted. The load line of the crane extending from the winch at the base of the boom section is trained over the secondary sheave, as well as sheave structure on the outermost end of the outer boom section. Elongated rod structure carried by one of the extendable boom sections outwardly of the crane has coupling means thereon engageable with the mast to initiate erection thereof after the proportionally movable boom sections have been extended a predetermined extent, normally after about 50% extension thereof.

Abstract: An apparatus and a method for controlling the operation of a reach tower crane, in which a horizontal boom can safely and securely be operated or stored by one operator in the cab, and in which even if sensors are out of order, the stability of the crane can be secured. The system has a plurality of sensors for detecting a condition of an actuator (6) actuating an apparatus to operate or store a horizontal boom (5), a controller (36) for sending a control signal based on signals from the sensors, and hydraulic apparatuses for controlling various actuators in accordance with the control signal. Further, an operation lever and an operation switch are used to extend or store the horizontal boom (5).