Abstract: A telescopic boom for a crane, access platform or the like comprises at least three telescopic boom sections the intermediate section being arranged to be extended by a hydraulic ram while the outer section being arranged to be extended by a pulley and chain arrangement. A telescoping boom safety system includes a wire rope and a pair of linked drag chains which extend from a first anchorage on the outer section around a guide to a second anchorage on the base section. Failure of the pulley and chain arrangement causes the safety system to prevent or contain relative movement of the outer and intermediate sections and thereby stop sudden and catastrophic retraction of the outer section.

Abstract: A crane or the like (e.g. an access platform or excavator), having a boom wherein the boom is lifted or lowered by one or more hydraulic rams or the like, the or each ram acting on a cradle on which the boom rests and in which it is free to move, the cradle being linked to the platform or the base of the crane or the like, at a point between the foot of the ram(s) and the foot of the boom or at the foot of the boom. This arrangement has the advantage that the boom stresses during lifting are evened out, and expensive accurate machinery of the boom pivot holes are avoided.

Abstract: A dynamometer, used to measure the tension on, speed of, and direction of movement of a hoist rope on a crane, includes a frame comprising three spaced apart blocks coupled to one another by pairs of thin flexible resilient portions. Two pulleys are mounted to the outermost blocks while an offset pulley, coupled to a tension monitoring load cell, is mounted to the central block and presses against the rope. One pulley has three permanent magnets imbedded about its periphery, two being axially spaced across from one another and the third being spaced radially 180.degree. from the others. Sensors mounted to the frame are positioned to sense the passing of the magnets to provide rope speed and direction of travel information in digital form. Tension information from the load cell and speed and direction information from the sensors are supplied to a microprocessor for processing.

Abstract: A boom for a crane or the like which comprises four longitudinal stiffening members interconnected with four substantially flat longitudinal plates in such a way that the boom has a substantially diamond shaped cross-section. Such a construction has considerable advantages as compared with normal rectangular section booms, e.g., reduction of stress at the corners, elimination of internal fillets, reduction of distortion and easier and better construction of the boom.

Abstract: A telescopic boom for a crane, access or load platform or the like, having power transmission lines extending along the boom to its head. In order to avoid problems which arise with such power lines when the bottom is extended or retracted the invention proposes the use of a flexible carrier which extends between a point at the outer end of the base section and a point mid way along the extended sections of the boom between the head and the end of the base section. This enables the power lines to be protected both when the boom is extended and when it is retracted.

Abstract: A mobile crane or aerial lift platform vehicle wherein the chassis comprises a horizontally disposed solid metal slab carrying axle/outrigger mountings and on which the boom or jib turntable is mounted. This has the advantage both of providing stability because of the weight of the solid chassis and of cheaper fabrication and assembly.

Abstract: Described herein are cranes and particularly those which are stability balanced, normally mounted on a truck or similar vehicle and provided with a boom of telescoping sections. The crane according to the invention has a boom provided with an upper lattice extension and a fly jib, attached (preferably pivotally), to the boom adjacent the top thereof or to the lattice extension at a point on the lower half of the extension. As this arrangement provides a reasonable length of boom, or lattice extension thereof, above the connection point of the fly jib, a substantial moment arm is provided enabling a relatively long and heavy fly jib to be employed giving greater stability to the top portions of the crane. Also the arrangement enables increased lift capability, at comparable radii, as compared with a standard crane, or similar lift capabilities at an increased working radius.

Abstract: The invention relates to a mobile crane or aerial lift platform vehicle wherein at least one of the axles is extendable and wherein a cylindrical housing carries the extendable axle beam and a steering actuator is carried on at least one of the beams and is connected to a steering link connected between the wheel and the outer end of the beam. The arrangement is such that the distance between the actuator and the steering link is not altered by extension or contraction of the beam relative to its housing.

Abstract: A mobile crane which has the advantages of both a telescopic cantilever jib and of a lattice strut or lightweight jib. This is achieved in accordance with the invention by providing a powered link which swings the foot of the base section of the telescopic jib between a forward position for use and a rearward position for stowage.

Abstract: A telescopic strut jib crane includes a jib with at least three telescopic sections and at least one tie rope of fixed length. The rope is fed between the head of the base section and head of the outer section around a pulley at the foot of an intermediate telescopic jib section. One end of the tie rope (12) passes around a support pulley (14) to the rear of the jib around first extension pulley (32) at the head of the outermost jib section (2), down the outermost jib section, around a second extension pulley (28) at the foot of the outermost section, to be anchored at or adjacent (26) the head of the intermediate jib section (4). The other end of the tie rope (12) extends from the support pulley (14) around a third extension pulley (34) at the head of the intermediate section (4), down the intermediate section and around fourth extension pulley (36) at the base of said intermediate section (4), and then to the head of the adjacent lower section (6).

Abstract: A crane having a novel data processing system which uses a microprocessor (22), to calculate mathematically the actual jib radius (R.sub.1) from inputs corresponding to jib head angle elevation, jib base elevation and jib length from head (9) to base (8). The system provides actual data which can be fed to a display (10) and which can actuate alarms (24), (26) on reading a safe load stored in a load table in a microcomputer of which the microprocessor forms a part. The actual data can also control motion cut offs, automatic luffing and automatic stowage. A novel dynamometer (30) is also included which can measure crane hoist loads, speed and direction.

Abstract: A crane of the telescopic jib type wherein the telescopic jib sections are driven for outward and inward telescopic movement by a chain cable or the like which is connected to the jib sections and movement of which in one direction drives the sections outwardly and movement of which in the other direction drives the sections inwardly. This enables a simple and relatively cheap drive means to be employed.

Abstract: Mobile cranes have a jib mounted on a platform or deck of a road vehicle so that the crane can be transported from one working site to another. Such a crane may have a counterweight on the rear of the crane jib superstructure and mounted so that it can be moved inwardly and outwardly relative the superstructure to balance the load on the jib. When the crane is to be driven along the rod, however, the jib is folded over the platform of the vehicle and in addition the counterweight is desirably removed from the jib superstructure and carried in a position on the vehicle platform where its weight best suits the vehicle suspension. In order to remove the counterweight, the superstructure is slewed to bring the counterweight to a position adjacent an upwardly inclined surface carried by the platform of the vehicle, the bottom surface of the counterweight being inclined at a corresponding angle to the horizontal equal to that of the inclined surface.

Abstract: A section for a telescopically extensible crane is octagonal in cross-section. The section has relatively thick upper and lower parallel plates, and side members each having a part inclined outwardly for each of the upper and lower plates and a central part generally perpendicular to the upper and lower plates. The central part of each side member may extend over more than half the height of the boom section and the inclined sections may be of differing lengths and thus inclined at different angles to the respective upper and lower plates. Preferably, the lower inclined sections are shorter than the upper inclined sections. The boom section may be reinforced by external belts, or by internal support plates.

Abstract: A rough terrain mobile crane in which the operator's control cab is mounted on a rotatable superstructure has all the controls grouped in the cab including a mechanical, preferably power assisted, steering system mechanically engagable when the cab is in a road travel position, an hydraulic steering system is alternatively engageable for on-site use and includes a separate directional control valve for steering road wheels on one of the axles, and utilizing the power assisted part of the mechanical steering.

Abstract: A rough terrain mobile crane in which the operator's control cab is mounted on a rotatable superstructure has sets of controls for vehicular drive, steering, lifting and boom motions grouped together in the control cab which is carried on a bearing provided on the superstructure together with the boom and pivotally connected hydraulic ram for raising and lowering it and the control cab is alternatively extended to a forward position at the front of the chassis and which may be beside an upstanding engine compartment for driving the crane from place to place and to a rearward position, by sliding and/or pivoting on the bearing, for use in operation of the crane.