Abstract: A pivot unit comprising a linear actuator; a rod assembly driven by the linear actuator; an output shaft driven by the rod assembly; a housing enclosing the rod assembly and a portion of the output shaft, and attached to the linear actuator; a saddle driven by the output shaft; a first stop arm operatively attached to the first arm and a first end of the output shaft; a second stop arm operatively attached to the second arm and a second end of the output shaft; a first shock absorber secured to a first side of the housing and constructed and arranged to accept a first end of the first stop arm; and a second shock absorber secured to a second side of the housing and constructed and arranged to accept a first end of the second stop arm.

Abstract: Implementations of cranes may include a first telescoping boom and a second telescoping boom coupled within the first telescoping boom. The second telescoping boom may be entirely within the first telescoping boom when the second telescoping boom is in a fully extended position.

Abstract: A waste pump removal apparatus for removing pumps from reception areas for maintenance. The waste pump removal apparatus includes a frame having front and back ends, a top and a bottom; a loader attachment coupled to the back end of the frame and adapted to mount to a loader; a pump attachment pivotably connected to the front end of the frame and adapted to be coupled to a waste pump; and an actuator mounted to the frame and in communication with the pump attachment for pivoting the pump attachment relative to the frame to remove the waste pump from a reception area.

Abstract: A lift device includes a base, a boom coupled to the base, and an actuator assembly having (i) a first end coupled to the base and (ii) an opposing second end coupled the boom. The actuator assembly includes a first actuator, a second actuator, and a coupler coupling the first actuator and the second actuator together at or proximate one of the first end or the opposing second end of the actuator assembly. The coupler is pivotally coupled to a pivot point of one of the boom or the base. The coupler pivots with the first actuator and the second actuator about the pivot point.

Abstract: A wheel loader front unit includes a frame for a wheel loader, the frame including an upper joint element and a lower joint element for connecting the frame to a rear unit of the wheel loader, and for transferring loads between the frame and the rear unit, the frame including a lift arm mounting point for a pivot connection of the frame and a lift arm for lifting an implement of the wheel loader. The upper and lower joint elements are arranged so that a first of the upper and lower joint elements, during use of the wheel loader, transfers a larger vertical load than a second of the upper and lower joint elements, and the lift arm mounting point is located closer to the first of the upper and lower joint elements than to the second of the upper and lower joint elements.

Abstract: A boom assembly includes a first boom, a second boom pivotally coupled to the first boom, and an actuator assembly having (i) a first end coupled to at least one of the first boom or the second boom and (ii) an opposing second end coupled to the second boom. The actuator assembly includes a first actuator, a second actuator flexibly joined to the first actuator at the opposing second end of the actuator assembly, and a rigid coupler positioned to fixedly couple the first actuator and the second actuator together at the first end of the actuator assembly. The rigid coupler is configured to pivotally couple the first end of the actuator assembly to the at least one of the first boom or the second boom. The first actuator and the second actuator are configured to move relative to one another in response to various loading conditions.

Abstract: A lifting apparatus comprises: a base part, a lifting rope, a sheave assembly, a first rotatably mounted sheave, around which the rope passes and from which the rope extends downwardly to a load, a second rotatably mounted sheave and a drive for moving the sheave assembly. The sheave assembly is mounted for pivotal movement relative to the base part about an axis of pivoting spaced from the axis of rotation of the first sheave and coincident with the axis of rotation of the second sheave. During movement of the load relative to the base part, the first sheave is moved by the drive to compensate for that relative movement, the movement of the first sheave being such that the vertical component of the movement of the first sheave relative to the load is less than the vertical component of the movement of the base part relative to the load.

Abstract: A crane for lifting and transporting loads includes a base frame, capable of transferring loads onto a support surface. A sliding element is slidably constrained to the base frame. An arm capable of moving the loads is hinged to the sliding element. A connection element has a first end hinged to the sliding element, and a second end constrained to the base frame in a mobile manner. Each of a pair of rod elements is hinged to the base frame and to the connection element to form an articulated quadrilateral. A first linear actuator is hinged to the base frame and to the connection element and to cause sliding movement of the sliding element relative to the base frame. A second linear actuator is hinged to the sliding element and to the arm to cause mutual rotation movement between the arm and the sliding element.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The method may include measuring first pressure ripples at the second chamber and reducing a magnitude of second pressure ripples at the first chamber. The pressure ripples may be transformed into a flow command by multiplying the pressure ripples by a gain and/or phase shifting. The gain and/or the phase shifting may be adjusted by feedback.

Abstract: A boom assembly includes a lower boom, an upper boom, and an actuator assembly. The lower boom has an upper end and a base end. The base end is configured to be pivotally coupled to a lift device. The upper boom has a lower end pivotally coupled to the upper end of the lower boom. The actuator assembly has (i) a first end coupled to at least one of the upper end of the lower boom and the lower end of the upper boom, and (ii) an opposing second end coupled to the upper boom. The actuator assembly includes a first actuator and a second actuator. The second actuator is rigidly joined to the first actuator at the first end of the actuator assembly and flexibly joined to the first actuator at the opposing second end of the actuator assembly.

Abstract: A material handling machine such a skid-steer loader includes an electrohydraulic control system for controlling flow between a boom lift cylinder, an accumulator, and a source of pressurized fluid that delivers a variable system pressure. The electrohydraulic control system is switchable between a standard or normal mode and a ride control mode. It is configured to charge the accumulator with fluid from the pressurized fluid source while isolating the accumulator from the lift cylinder during operation in the standard mode and is configured to isolate the accumulator from the pressurized fluid source and to couple the accumulator to the lift cylinder during operation in the ride control mode. The accumulator is charged to a maximum pressure output by the source of pressurized fluid during the standard operating mode and pressure-balanced with the lift cylinder prior to initiation of operation in the ride control mode.

Abstract: A fluid circuit includes a pressure fluid source, a switching valve, and a cylinder device having first and second chambers and partitioned by a piston. A first accumulator is configured to communicate with the second chamber when pressure fluid is supplied to the first chamber and to accumulate part of the pressure fluid from the second chamber. A pressure booster is connected in hydraulically parallel to the first accumulator, the pressure booster communicative with the second chamber when the pressure fluid is supplied to the first chamber to boost pressure of the pressure fluid by using part of the pressure fluid from the second chamber. A second accumulator accumulates the pressure fluid whose pressure is boosted by the pressure booster.

Abstract: Switch gear for interconnecting a plurality of power transmission lines including a number of high voltage switches arranged in three phase unitized relationship for routing power in one or multiple directions. The switches are pre-mounted on a beam to form a unitized assembly which is attached in the field to a vertical support structure or substation structure. The unitized assembly includes a telescoping base design that permits the width of the unitized assembly to be reduced so that the assembly can be transported by truck to the installation site and then the switch assembly may be extended to the final width for installation at the site. The telescopic base design is preferably cantilevered and includes free rolling capability for easily manually reducing or expanding the width of the unitized assembly when the beam is lying on a ground surface.

Abstract: An adjustable fall arrest system is disclosed, where the system employs a four-bar linkage and cantilevered beam arrangement to provide the fall arrest support.

Abstract: Material lining the inside surface of a section of pipe is removed by a hydrodemolition nozzle assembly mounted on a working end of an elongated boom. The opposed end of the boom is supported outside the pipe on a movable support for inserting and retracting the boom from the inside of the pipe. The nozzles remove the liner while the working end of the boom is supported by a wheel resting on the liner that has not yet been removed and that rolls along the inside liner as the pipe is made to revolve around the boom. The nozzles are oriented to eject the liner and water downstream and away from the boom.

Abstract: A mast-raising mechanism for raising a mast of a mobile lift crane to an operating position includes a hydraulic cylinder extendable to raise the mast. The hydraulic cylinder includes a first end pivotally coupled to a rotating bed of the crane and a second end spaced apart from the first end. A first arm includes a first end pivotably coupled to the second end of the hydraulic cylinder. The hydraulic cylinder extends to press the first end against a bearing surface on the mast. The first arm also includes a second end spaced apart from the first end. A second arm includes a first end proximate the second end of the first arm and a second end spaced apart from the first end. The second end of the second arm is pivotably connected to the rotating bed. A biasing mechanism urges the first arm towards the second arm.

Abstract: A roof rack for loading and unloading cargo to and from the roof of a motor vehicle is described. The roof rack is characterized by enabling the cargo to be loaded at an accessible height and then lifted onto the roof of the motor vehicle while the cargo is maintained in a fixed position. In another embodiment, the cargo is reoriented from a first orientation to a second orientation during the loading and unloading procedure.

Abstract: A boom truck includes a telescopic lifting boom with a lifting unit and a support structure having a first support arranged on the chassis of the boom truck. A second support in the form of an elongated bearing and support beam body extends in the longitudinal direction of the boom truck. The beam body is pivotally mounted to the first support about a rear bearing axis, whereas the lifting boom is pivotally mounted to beam body about a front bearing axis. Actuators act on the beam body and the lifting boom as a unit and act to pivot the lifting boom about the front bearing axis.

Abstract: A crane for mounting on a truck includes a base. The base includes a cargo bed welded or fastened to a frame and the frame for fastening to a chassis of a truck. The crane further includes a boom rotatable relative to the base between a vertical position and a horizontal position; a boom hoist operable to raise and lower the boom between the positions; and a load hoist operable to hoist cargo located proximate to a rear end of the truck when the boom is in the vertical position and operable to carry the cargo toward a cab of the truck as the boom is lowered to the horizontal position, thereby loading the cargo onto the cargo bed.

Abstract: A lift crane includes a carbody; ground engaging members elevating the carbody off the ground; a rotating bed rotatably connected to the carbody; a boom pivotally mounted at a first end to the rotating bed with a load hoist line extending adjacent a second end of the boom; a boom hoist mechanism that can be used to change the angle of the boom relative to the rotating bed during crane operation; and a boom raising assist structure connected to the boom. The boom raising assist structure preferably includes at least one ground engaging member in contact with the ground; and a boom elevating member extending between the assist structure ground engaging member and the boom. The boom elevating member supports at least a part of the weight of the boom.

Abstract: Lifting apparatus (1) provided with a raisable element (4) and a hydraulic system (5), which includes a mechanical locking system based on at least one lock element (7) articulately connected to a free end of a moving rod (5b) of the hydraulic system (5), where the lock element (7) includes an internal slot (8) through which a protuberance (9) attached to a fixed part (5a) of the hydraulic system (5) can move. The internal slot (8) is provided with at least one recess (10) in which the protuberance (9) may be lodged in order to lock the raisable element (4) in different positions. The centre of gravity of the lock element (7) is arranged in such a way that, in an unlock situation, an imaginary line that connects the centre of gravity with the articulated connection between the free end of the moving rod (5b) and the lock element (7) forms a certain angle with the vertical. The locking system locks itself automatically and is easy to use.

Abstract: A lifting device for handling and/or moving loads, including two vertical booms which via one of their ends are pivotally connected to a base and via their opposite ends are pivotally connected to a horizontal beam, forming a frame for the lifting device wherein at least one cylinder is connected to at least one of the vertical booms so as to be able to turn the lifting device around the pivot point. The horizontal beam is further pivotally connected to at least one tension rod. The vertical booms, the tension rods and the horizontal beam will then be pivotal in relation to each other. By means of the present invention, a less torque-critical lifting device is provided, as the vertical booms, when handling and/or moving a load, will take up compressive forces, while the tension rods will take up tensile forces.

Abstract: Hitch Hoist system provides an effective and efficient means through which users may lift heavy objects into the backs of trucks. This innovative product preferably features four main components, including two legs, a coupling tee, and a boom containing a winch. The components are preferably held together using ordinary hitch pins, and can therefore be easily assembled and disassembled whenever necessary. Consumers may use this product to lift extremely heavy objects when help is not available, or when conserving time and labor is necessary. The present invention is convenient for home use, military use, as well as use in junkyards, farms, or construction sites.

Abstract: The invention relates to a vehicle crane, especially a mobile crane, automobile crane, or track-laying crane, comprising a superstructure which is embodied as a top slewing crane and encompasses a vertical tower and a boom located on the tower.

Abstract: A mobile lift crane includes a carbody having moveable ground engaging members; a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members; a boom pivotally mounted on a front portion of the rotating bed and a mast mounted at its first end on the rotating bed and having a second end; and at least one hydraulic cylinder pivotally connected at a first end to the rotating bed. The hydraulic cylinder is positioned and configured so as to be able to raise the second end of the mast from the mast being in a near horizontal position to a position where the mast is used during crane pick, move and set operations. In a preferred embodiment, at least one arm is pivotally connected at a first end to the rotating bed and at a second end to the hydraulic cylinder. The arm and cylinder are connected together such that extension and retraction of a piston within the hydraulic cylinder causes the second end of the arm to raise and lower.

Abstract: A flat-bed truck system and method for efficiently delivering and unloading items using special crane, lift or hoist elements. The cranes are foldable downward into a horizontal position. Lower plural and parallel drive elements are used to drive upper pivoting arms which are connected by a cross-bar element. The cranes are designed with a low center of gravity so they may be positioned at various points around the bed of the truck. The lower plural drive elements are fixed in a horizontal position by brackets which may be easily applied and removed.

Abstract: The invention relates to a harvester crane, which includes a set of booms, which are attached by means of a pedestal and rotating device to a chassis machine, in which the set of booms includes a main boom, which is pivoted at its lower end by a lower pivot to the pedestal; and an articulated boom, which is pivoted by an upper pivot to the opposite end of the main boom and which extends its path mainly forward from the main boom; operating devices, i.e. a lift device and a transfer device, operating the booms. The lower pivot of the main boom is located low down near to the rotating device and the pedestal is fork-shaped, the lower arm and the lift cylinder being located at least partly inside it.

Abstract: An improved boom-mounted jib unit (10) is provided having an increased range of motion and work envelope, which allows a user to lift heavier loads an otherwise work with less jib interference, as compared with prior jib units. The jib unit (10) includes a base (12) and a mounting component (28) permitting the unit (10) to be detachable secured to the upper end of a primary boom (22). The unit (10) also has a boom arm (14) made up of upper and lower arms (16, 18). The arm (14) is articulated by a dual piston and cylinder assembly (20) having first and second piston and cylinder assemblies (84, 86) coupled between the base (12) and arm (14).

Abstract: The present invention relates to a mobile crane boom having a self-sufficient energy supply arranged on it for supplying hydraulic energy to at least one hydraulic load arranged on the mobile crane boom. The supply of the hydraulic load arranged on the mobile crane boom is therefore not carried out by means of a hydraulic unit arranged on the revolving superstructure of the crane, which provides the hydraulic energy to each hydraulic load via hoses, but by means of a hydraulic unit which is arranged in the upper reaches of the mobile crane boom or in the area of the linkage of any second boom section. By arranging the hydraulic unit directly on the boom, the hoses normally required for supplying the hydraulic loads can be eliminated.

Abstract: A mobile hydraulic hoist unit which is readily maneuverable to a position straddling a load and then conveniently operated to lift and securely transport such load over a variety of terrains and surfaces and to safely and accurately deposit that load at a specific location. The hoist unit comprises a generally “U” shaped base frame having spaced side members provided with multi-terrain wheel assemblies, a closed forward end having a hitch member for releasable attachment to a towing vehicle, a rearwardly open center section adapted to receive and straddle the load, a power cylinder, a boom operated by the power cylinder for lifting and securely holding the load in a transport position during movement of the hoist unit and for accurately depositing the load at the desired destination.

Abstract: The invention concerns a material transloading equipment unit with an undercarriage and a turntable connected with this undercarriage by means of a track ring, on which an arm that can be pivoted by means of at least one hoisting cylinder is pivot-mounted. According to the invention, on the one hand at least one additional pivot point for the arm is provided on the turntable and/or on the boom foot, and at least one additional pivot point is provided in the arm or in a pivot plate on the arm. This allows a number of possible combinations for the kinematics of the arm.

Abstract: A measurement system uses dual axis force sensor pins to effectively assess the tipping moment of a load-bearing vehicle and anticipate imminent tipping in any direction. The pins are installed in the pivot points of the boom of a lift vehicle and its main lift cylinder, substituting the standard structural pins presently used. For non-traditional boom support arrangements, one sensor pin for each moving part attachment to non-moving turntable is required. Each of the sensors provides the actual force components acting on the sensor in two perpendicular axes. The output signals are then utilized to assess vehicle stability and detect when the machine is approaching instability in order to warn the operator and/or restrict vehicle movements.

Abstract: A pipelayer is provided which is capable of effectively transporting pipes or the like and stably carrying out load hoisting operation on a slope. The pipelayer comprises: an undercarriage; an upper revolving superstructure mounted on the undercarriage so as to turn around freely upon the undercarriage; a boom supported by the upper revolving superstructure so as to be freely raised and lowered; a pulley block attached to the boom through a universal joint; a hoist mounted on the upper revolving superstructure; a hoist hook hung by a wire rope that is paid out from the hoist and wound around the pulley block.

Abstract: An apparatus transforms a motorized frame mounted on crawler tracks and having a rotatable horizontal platform, into a pipeline laying machine or the like. A first structure is hinged to the platform on a horizontal axis at one end, at its other end, has a coupling intended to be secured to a track guide carriage. A second structure which, at its free end carries a lifting member, is hinged on a horizontal axis to the coupling.

Abstract: A boom arrangement for moving a work head, which boom arrangement comprises a pillar mounted on a bearing around the vertical axis in a rotating manner, with mounting and rotational members; a lifting boom; a transfer boom; a lifting cylinder arranged between the pillar and the lifting boom; an intermediate lever mounted on the lifting boom; a tow bar, a transfer cylinder arranged between the lifting boom and the tow bar; an intermediate arm; and an arm. The lifting cylinder is mounted by the end on the side of the lifting boom on the intermediate lever, which is mounted on a bearing on the lifting boom in the zone between the end on the side of the lifting boom pillar and the middle of the lifting boom. The tow bar is mounted on one end of the intermediate lever. The arm is mounted on the tow bar by its one end and on the transfer boom by its other end.

Abstract: A boom mechanism that is cooperable with a lift vehicle or base structure includes a tower boom and an upper boom liftable in a dependent relationship by a single lifting mechanism. The tower boom and the upper boom are respectively pivotally secured to an upright having a fixed orientation by a tower link or the like. A timing link is secured between the tower boom and the upper boom, and a lifting mechanism is secured between the upright and the upper boom. As the upper boom is driven by the lifting mechanism, the timing link secured to the tower boom causes the tower boom to pivot about a tower boom nose pivot, thereby raising both the upper boom and the tower boom in a dependent relationship. The construction helps to minimize the need for tail and frame counterweight by controlling a position of the platform in configurations of both forward and rearward instability. As a consequence, the gross vehicle weight can be considerably reduced.

Abstract: In order to be able to shift a leader (18), which is disposed on a travelling chassis (10) via a carrying mechanism (16), both towards the front and also towards the rear into a substantially horizontal position, the carrying mechanism (16) has at least one guide arm (24) which is adjustable in length and which comprises a double-acting hydraulic working cylinder.

Abstract: Load-bearing apparatus, such as a boom lift, including first and second arm portions, in which at least one element, such as a hydraulic cylinder, is provided for selectively imparting a predetermined dependent relationship as well as a predetermined independent relationship between the first and second arm portions. The manufacture of such load-bearing apparatus can be customized by preselecting the dependent and independent relationships by altering given parameters.

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 crane having a hydraulically actuated jib system, at least one cylinder for actuating the jib system and an apparatus for monitoring the pressure in the cylinder, which indicates the crane loading, wherein the feed flow of hydraulic fluid to the cylinder is controllable by varying the cross-section of a valve, and a signal is produced in dependence on the variation in pressure in relation to time which is detected in the cylinder or the variation in the loading of the piston guided in the cylinder in relation to time, which signal actuates the drive for adjusting the valve cross-section in the direction of a reduction in the detected variation in pressure or loading.

Abstract: A mechanism for loading and unloading a container onto a tray attached or attachable to a track or trailer vehicle. The mechanism includes a transverse assembly at each end of the tray, each assembly incorporating a centrally mounted telescoping boom, a lower part of which incorporates an extension to which opposed hydraulic rams are linked. The hydraulic rams control the swinging movement of the boom when one retracts and the other extends.

Abstract: In connection with a pair of pivotally connected articulating booms there is a pair of double-acting hydraulic cylinders which control the vertical pulling of well pipe, such that a boom assembly in conjuction with an improved winch assembly willgenerate at least a 1500 pound perpendicular pulling force to a vertical height of at least 23.5 feet. This is done with a mini hoist, releasably mounted upon a hydraulically self-propelled 4.times.4 vehicle. The entire weight of the mini hoist is less than 1500 pounds and in the collapsed stage can fit within a box truck or on a pickup truck.

Abstract: A loader composed of: a turntable (2) for connecting said loader to a machine base; a mounting plate (2a) connected to the turntable; a main arm (3) having a first end connected to the turntable; a secondary arm (4) articulated to the main arm (3); a lift cylinder (5) and a maneuvering cylinder (6) for controlling the arms, each of the cylinders having first and second ends, with the first end of the lift cylinder (5) being connected to the mounting plate (2a) and the first end of the maneuvering cylinder (6) being connected to the main arm (3) at a location proximate to the first end of the main arm (3); and a common link plate (9) to which the second end of the lift cylinder (5) and the second end of the maneuvering cylinder are connected in order to control the loader, wherein: the main arm (3), the lift cylinder (5) and the maneuvering cylinder (6) are situated substantially in the same shear plane; and the main arm (3) is positioned between each of the lift cylinder (5) and the maneuvering cylinder (6) a

Abstract: A lifting device for attachment to a vehicle trailer hitch or the like. The device includes a hitch bar for attachment to the trailer hitch. A lateral extension arm is mounted on the hitch bar and a riser arm is rotatably mounted to the lateral extension arm. A boom arm is mounted on the riser arm, the boom arm having load attachment elements for attaching a load thereto. Also provided is a rotating element attached to the lateral extension arm and the boom arm for rotating the riser arm about the lateral extension arm to raise and lower the riser arm relative to the hitch bar. Raising and lowering of the riser arm moves the boom arm to transcribe a predetermined arc lying in a vertical plane. It is preferred to have the hitch bar centered on a platform centerline wherein the vertical plane intersects the centerline. The predetermined arc may be from about 130 degrees to about 150 degrees, and preferably 140 degrees, with respect to the bed of the vehicle.

Abstract: A swing type front working mechanism 7 is provided, the front working mechanism 7 having a foot portion of a lower boom 8L of a boom 8 pivotally supported on brackets 12a through a pin 18. A cross-link 40 is connected between the bracket 12a and an upper boom 8U by pins 41 and 42 only along the right lateral side of the boom 8, and no cross-link is provided on the side of an operator's cab 6. In the case of a singular cross-link arrangement of this sort, the boom 8 could be operated under biased load distribution, and therefore the lower boom 8L is likely to be subjected to greater stresses or greater lateral bending stresses on the side of the cross-link 40. A boom operating hydraulic cylinder 43 is located in a position which is shifted aside from a center axis A1 of the lower boom 8L in a direction away from the operator's cab 6, thereby forming a lateral load buffer as a counter measure which suppresses or buffers lateral bending stresses of the sort as mentioned above.

Abstract: An upper boom compensation system for an aerial device having an articulating boom assembly. The lower boom is raised and lowered by a special double cylinder having two pistons and a common piston rod. A hydraulic circuit is arranged to transfer fluid between the lower boom cylinder and the upper boom cylinder in a manner to raise and lower the upper boom correspondingly to raising and lowering of the lower boom. The upper boom can also be controlled independently of the lower boom.

Abstract: A lifting apparatus is provided that is especially suited for mounting on a towing vehicle and for lifting a vehicle. The invention comprises an L-shaped member with a boom leg. The L-shaped member pivots on a base frame pivot and an upper pivot. Linkage arms hingeably connect the upper pivot to a camming crank. The camming crank has a forward direction of rotation and a rearward direction of rotation, and an actuator pivot. In the forward direction of rotation, a force means rotates the camming crank about the upper frame pivot, causing the linkage pivot of the camming crank to pull the linkage arms, so that the linkage arms tilt the L-shaped bar and so raise the boom leg. In the rearward direction of rotation, the force means rotates the camming crank in the opposite direction about the linkage pivot, pushing the linkage arms so that the linkage arms tilt the L shaped bar, lowering the boom leg. The force means can be an extending and retracting actuator such as a hydraulic cylinder and piston.

Abstract: A hydraulic excavator includes a boom comprising an articulated first and second boom member, an arm, a bucket, a boom cylinder for operating the boom, an arm cylinder for operating the arm; and a bucket cylinder for operating the bucket. The boom cylinder is cooperatively associated with the boom to establish a geometry wherein, during operation, the axis of the boom cylinder can never pivot rearwardly across a dead point of the boom and therefore eliminate the possibility of dead locking of the boom during operation.

Abstract: A truck mounted crane assembly includes a turntable lock, a boom rest which interacts with the piston and cylinder device, and a swing away hoist mount. The turntable lock includes a pin which is manually retractable upon rotation of a handle from a position preventing relative rotation between a turntable and a pedestal to a position allowing such relative rotation and which can be secured in the first and second positions. The boom rest is mounted on the boom and rests on the cylinder of the piston and cylinder device when the boom is lowered to a predetermined position, thus taking much of the pressure off the piston. The boom rest is movable from a position in which it is capable of supporting the boom to a position in which it is incapable of supporting the boom and in which the boom is thus lowerable below the predetermined position. The provision of the turntable lock and boom rest obviates the need for a cradle rest for the boom.

Abstract: A crane for material handling is constituted by a boom (1) and a fixed column (2) for supporting the boom (1). The boom (1) is articulated for vertical swinging movement on and relative to a rotating device (3), mounted for rotation about a vertical axis on or in the column (2) and provided with a torsion-transmitting member (4) passing through the column (2) and coacting at its lower portion with a rotation activator (5) of the boom (1). The boom (1) is provided at its free end with a hook, a grapple or another tool, or with a like rotatable actuator.