Abstract: A method of upgrading a knuckle-boom crane to a heave-compensating crane includes: removing a knuckle-boom from a main boom; mounting a main boom extension to the main boom for increasing the length of the main boom; and mounting a heave-compensating boom at a far end of the main boom extension such that the heave-compensating boom extends in a downward vertical direction (Z) in operational use of the heave-compensating crane. The heave-compensating boom is configured to be pivotable with respect to the main boom extension in both horizontal directions (X, Y). A heave-compensation system is provided to the knuckle-boom crane, wherein the heave-compensation system compensates for horizontal variations by controlling the orientation of the heave-compensating boom relative to the main boom extension, and compensates for vertical variations by means of a further vertical heave-compensation system, such as a winch-based heave-compensation system.

Abstract: Provided is a chain power transmission mechanism and a silent chain each having a simple configuration, easy to manufacture, and capable of reducing noise in the entire chain power transmission mechanism. Link plates of the silent chain include an inner-flank-engagement link plate which engages with a sprocket in an inner flank engagement mode and an outer-flank-engagement link plate which engages with the sprocket in an outer flank engagement mode. The inner-flank-engagement link plate and the outer-flank-engagement link plate are arranged such that combinations of the link plates at positions where engagement with and disengagement from a plurality of the sprockets are synchronized include a combination in which at least one of the link plates is different in engagement mode from another link plate.

Abstract: A portable derrick system for use in hoisting and lowering loads at a plurality of job sites, comprising, in combination: a boom subassembly, a boom head subassembly, a mast support subassembly, a mast head subassembly, a load-carrying line, a winch capable of cooperating with said line, power means for driving the winch, means for pivoting the boom assembly, means for controlling said pivoting means, the foregoing elements of the invention capable of being transported by humans to elevated positions such as, without limitation, rooftops and terraces, and wherein the aforementioned are capable of repeated assembly and disassembly at a plurality of job sites and serving to facilitate the elimination of the need for a street-level crane.

Abstract: Provided is a tensioner capable of stabilizing an oil pressure in an oil pressurizing chamber. The tensioner includes a pressure adjustment unit. The pressure adjustment unit includes a unit case attached to the housing or the plunger, a moving member disposed in the case inner space to be capable of moving closer to and farther away from the oil pressurizing chamber, and a pressure adjustment biasing unit which biases the moving member toward the oil pressurizing chamber. A gap between an inner wall of the case inner space and the moving member is configured to be held in a liquid tight state at any position between a position where the moving member is closest to the oil pressurizing chamber as a result of moving and a position where the moving member is most distant from the oil pressurizing chamber.

Abstract: The invention relates to a method of weathervaning a work machine in out-of-operation mode, in particular of weathervaning a revolving crane/revolving tower crane or a concrete spreader mast, wherein the work machine comprises at least one slewing part that is rotatable about a substantially vertical axis by means of a slewing gear, and wherein in a first step one or more wind data are measured by means of a measurement system arranged at the work machine; an optimum position of the slewing part is determined for an optimum weathervaning in dependence on the detected wind data; and the slewing gear drive is subsequently correspondingly actuated to bring the slewing part into the determined position.

Abstract: A mobile crane has an undercarriage, a superstructure arranged on the undercarriage, a slewing gear by which the superstructure may be rotated relative to the undercarriage, a slewing gear brake that acts on the slewing gear to brake a rotation of the superstructure, and a jib mounted on the superstructure as to be adjustable in luffing angle and/or in length. The mobile crane additionally contains a dolly coupling arranged on the jib and by which the jib is coupled to a mobile crane dolly during dolly travel with the superstructure in an extended position. The mobile crane further has a sensor interface for connecting a dolly coupling sensor, and a controller that is adapted to ascertain during dolly travel, in dependence on a signal received from the dolly coupling sensor, whether the jib rests on the mobile crane doll, and to activate the slewing gear brake if it does not.

Abstract: A plate link chain for a continuously variable cone pulley transmission is disclosed. The plate link chain includes a first chain link, a second chain link, and a third chain link having plates and being connected to one another by joints having rocker pins. The rocker pins have end faces configured to transmit friction forces between the plate link chain and cone pulleys, wherein at least one of the plates has at least one overlapping tip. The first, second, and third chain links form a triplet and have different plate assemblies comprised of a first plate unit or a second plate unit, each of the chain links having at least one plate positioned transversely to a running direction of the plate link chain and are repeated in the running direction of the plate link chain.

Abstract: Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

Abstract: A height adjustment assistance device includes an initial state determination part for determining whether a suspended cargo has been lifted from a ground at a start of lifting work, a height detection part for detecting a height of a counterweight from the ground, a storage part for storing an initial height, a calculation part for calculating a target value for correcting the height of the counterweight from the ground based on the initial height and a post-work height, a notification part for notifying an operator of information regarding the target value, and a length adjustment device for adjusting a length of a hanging member by operating in a manner to change the length of the hanging member extending from a tip of a mast to the counterweight.

Abstract: In embodiments, motion may be arrested and/or dampened using a motion arresting and dampening device comprising a lifting spreader bar, one or more bar mounted winches, deployment wire, a restorative inflation device, restraining wires and winches, hoses and controller, mechanical connection release system circuitry. Multiple restraints from winches mounted strategically on a vessel crane's boom may be applied to the spreader bar to restrain the bar during the lifting operation. The forces induced into the lifted object by the movement of the crane as it deploys the object into installation position are attenuated by the physical restrain of the adjustable wires. These adjustable wires may also be used to provide rotation of the object during final alignment of the object during installation.

Abstract: A stabilizer leg arrangement with a stabilizer leg (25), which is extensible by a hydraulic cylinder (27) into a supporting position in contact with the ground. A piston (32) divides the internal space of the hydraulic cylinder into first and second chambers (34, 35), wherein these chambers are configured to come into fluid communication with each other through a flow channel (41) in the hydraulic cylinder when the piston reaches an advanced end position and abuts against a stop surface. An electronic control device (72) is configured to establish information as to whether or not the stabilizer leg is in the supporting position while taking into account a measuring value (V1) related to the hydraulic pressure in the first chamber (34). The invention also relates to a corresponding method and a mobile working machine comprising such a stabilizer leg arrangement.

Abstract: A limited rotation slewing ring crane may include a pedestal, a column rotatively coupled, about a first rotation axis, to the pedestal by a slewing ring rotative coupling, and stops for limiting the relative rotation of the column with respect to the pedestal. The crane may also include a rotative sensor adapted to measure a rotation angle of the column with respect to the pedestal. The rotation sensor may include a tubular body axially extending from the base of the column, a stationary body connected to the pedestal and a wheel. A second rotation axis of the wheel may be offset with respect to a first rotation axis of the column with respect to the pedestal.

Abstract: The present invention addresses the problem of providing a crane that can ascertain the state of an area surrounding a hook or a cargo suspended on the hook and that can simultaneously ascertain a braking distance during stopping operations. The invention comprises: drive devices 31-34 that move a boom 7; a control apparatus 20 that controls the operation state of the drive devices 31-34; a camera 41 that photographs, from the distal end portion of the boom 7, an area below said portion; and image display devices 43 and 65 that display the image photographed by the camera 41. For the purpose of stopping the movement of the boom 7, the control apparatus 20 filters basic control signals S for the drive devices 31-34 to create filtered control signals Sf, controls the drive devices 31-34 on the basis of the filtered control signals Sf, estimates the braking distance for the boom 7, and displays the same on the image display devices 43 and 65.

Abstract: The present disclosure relates to a crane, in particular an offshore crane, having a slewing gear and a hydraulic slewing gear drive, wherein the slewing gear is held in its position via a holding torque applied by the hydraulic slewing gear drive, and wherein an overload safety device is provided having at least one detection means for detecting the outreach and/or the position of the crane hook and having at least one pressure relief valve, with the system pressure applied to the hydraulic slewing gear drive via at least one pressure relief valve can be regulated in dependence on the outreach and/or on the position of the crane hook.

Abstract: Provided is a crane with a main boom and a back mast, of which at least one comprises a first mast upper part comprising at least one mast section and a first mast lower part comprising at least one mast section, and a first mast tilting. The first mast tilting member is arranged between the first mast upper part and the first mast lower part, and has a straight hoisting state wherein the first mast upper part and the first mast lower part are essentially in line with each other, and a tilted hoisting state wherein the first mast upper part is tilted with respect to the first mast lower part.

Abstract: A crane vehicle includes: an operation unit; a winch device configured to operate at a speed corresponding to an operation amount of the operation unit; a weight detection unit; a storage unit configured to store a time-weight target characteristic indicating a target in temporal change of a detected value at the weight detection unit for a maximum operation amount input from the operation unit; and a control unit configured to perform feedback control of an operation speed of the winch device such that the detected value follows the time-weight target characteristic in a case where the maximum operation amount is input from the operation unit, the control unit being configured to set the operation speed of the winch device at the speed corresponding to the operation amount of the operation unit, in a case where fluctuation of the detected value has converged in a predetermined range.

Abstract: A transmission belt includes: a plurality of elements, each having a plate shape, arranged sequentially in a ring manner; and a single-line ring having a belt shape and binding the elements together in a ring. Further, each of the elements includes pillar portions so that the single-line ring is inserted and a locking edge, provided on one surface in a plate thickness direction of the element, indicating a boundary region from which a plate thickness of the element changes, the pillar portions have respective ends, the ends having portions in a curved shape each having a predetermined curvature radius along a plane parallel to the single-line ring, and the portions in the curved shape include a first portion being formed on a front side at one end of the inner space, and a second portion being formed on a rear side at another end of the inner space.

Abstract: The invention relates to an apparatus for compensating diagonal pull in cranes having at least one boom, having a boom drive for adjusting an angle and/or a length of the boom and/or for traveling a trolley, and having a control/regulation apparatus for controlling/regulating the boom drive. The invention is further directed to a crane having a corresponding apparatus.

Abstract: A crane having an undercarriage, a superstructure pivotable about a slewing axis relative to the undercarriage, a counterweight unit and a counterweight adjustment device. The counterweight adjustment device includes a telescopic frame which is fastened to the superstructure and has a telescopic longitudinal member, a counterweight unit arranged to be displaceable along the frame, a drive unit for displacing the counterweight unit and a kinematic unit to telescope the frame in a driven manner. A jetty is fastened to a rear end, remote from the slewing axis, of the longitudinal member, the counterweight unit is displaceable along the frame in the region of the superstructure as far as the jetty, the counterweight unit is able to be fastened to the jetty and the counterweight unit is able to be telescoped in and out on the jetty with the frame.

Abstract: A gantry crane for a container includes a portal main frame, a traveling mechanism, a translation mechanism, a hoisting mechanism and a spreader assembly. The spreader assembly includes a spreader body, two telescopic girders and a drive assembly. The drive assembly includes a cam, a sliding way and two sliding blocks. Two arc-shaped first sliding grooves are circumferentially provided on the cam. A middle of the sliding way is rotatably connected with the cam. Two sides of connection of the sliding way and the cam on the sliding way are provided with a second sliding groove. Each sliding block matches with the first and second sliding grooves, and can slide back and forth along them. The telescopic beams are slidably connected to the spreader body, and are symmetrically provided and connected to the sliding blocks, respectively.