A hydraulic actuator for a mobile crane, in particular for a locking device of a telescoping device. The hydraulic actuator has a double chamber cylinder with a first cylinder chamber and a second cylinder chamber oriented in an opposite direction to the first cylinder chamber, a first piston rod for the first cylinder chamber, and a second piston rod for the second cylinder chamber. A first restoring spring restores the first piston rod to its main position and a second restoring spring restores the second piston rod to its main position. The main position of the first piston rod is its pushed-in position and the main position of the second piston rod is its extended position.

An extension boom system for heavy equipment having, the extension boom system including a first actuator mounted on a base, and connecting a second stage, a second actuator mounted on the second stage and connecting the second stage to a third stage, a third actuator mounted on the third stage and connecting the third stage to an extendable portion, and a controller configured to control the first actuator, the second actuator, and the third actuator so as to selectively operate in a first operation mode and a second operation mode. In the first operation mode, the first actuator, the second actuator, and the third actuator are operated substantially simultaneously, and wherein in the second operation mode, two of the first actuator, the second actuator, and the third actuator are actuated substantially simultaneously, while another of the first actuator, the second actuator, and the third actuator is not actuated.

A telescoping crane boom having a rotary locking mechanism. A motor drives a rotating element about an axis parallel to the axis of the crane boom. The rotation of the rotating member causes a pin to selectively lock and unlock sections of the telescoping crane boom.

A boom extension and contraction mechanism for a crane apparatus includes: a flow passage switching mechanism that switches a flow passage of the hydraulic oil between the cylinder-to-boom connection switching cylinder side and the boom member connection switching cylinder side; a hose reel configured to reel out a hydraulic hose as a telescopic cylinder is extending, and to reel off the hydraulic hose as the telescopic cylinder is contracting; a cable used to supply power and transmit a signal between a swivel base and a boom; and a cord reel configured to reel out the cable as the telescopic cylinder is extending and to reel off the cable as the telescopic cylinder is contracting. The code reel and the hose reel are arranged on the base in a direction in which the boom extends and contracts.

A boom assembly for a lift device includes a plurality of telescoping boom sections. The plurality of telescoping boom sections include a base boom section, a mid boom section, and a fly boom section. The plurality of telescoping boom sections define an inner volume. The boom assembly also includes a push tube coupled to the base boom section and a support member positioned within the inner volume. The support member includes sidewalls having an inner surface and an outer surface. The boom assembly also includes a power track positioned within the inner volume that includes a plurality of movable links, a first supported portion that interfaces with at least one of the inner surface of the support member and a surface of the push tube, and a second supported portion that interfaces with the outer surface of the support member.

There is provided a boom extending and retracting apparatus that can improve the convenience of the telescopic boom while reducing the burden on the operator. The boom extending and retracting apparatus of the crane chooses the mode of the fluid circuit between the normal fluid circuit and the differential fluid circuit to slide a plurality of boom members by one telescopic cylinder. After the operating lever is turned to an extension side and the controller starts extending the telescopic boom using the differential fluid circuit, when the operating lever is turned to the extension side again via the neutral position, the controller chooses the normal fluid circuit to extend the telescopic boom using the normal fluid circuit.

A telescopic boom extension device includes a cylinder-boom coupling mechanism, an inter-boom fixing mechanism, and a driving mechanism that drives the foregoing two. The driving mechanism has a hydraulic supply part and a drive source generation part. The hydraulic supply part includes an AOH and is provided at a cylinder tube of a telescopic boom. The hydraulic supply part supplies operating oil selectively to actuators driving a B pin and a C pin. The drive source generation part includes an air hose and supplies compressed air to the AOH. The air hose is wound around a hose reel in an unrollable manner.

A vehicle crane having a telescoping jib, comprising a basic box with linearly displaceable inner boxes and a lifting cable with a load picking-up device. A fastening region is arranged on the basic box or on a head end of one of the inner boxes, and a bracing apparatus is securable to the fastening region by a connecting end. To simplify rigging/de-rigging of the vehicle crane in relation to the bracing apparatus, the fastening region is formed for mounting the bracing apparatus on the basic box or on one of the inner boxes such that a bracing apparatus that is freely suspended on the lifting cable is coupled to the fastening region with the connecting end being brought close to the fastening region by movements of the vehicle crane, retraction and extension of the inner boxes, raising and lowering of the load picking-up device, and/or luffing of the telescoping jib.

A container trailer crane has an apparatus that includes a base, a crane arm, an outrigger, and a mechanical ram that is used in both positioning the outrigger and the crane arm.

The telescopic lift arm (1) for self-propelled operating machines (10), such a lifters, telehandlers and the like, comprises three tubular elements (21, 22, 23, 24, 25, 26), having a decreasing section and telescopically connected to one another to define a support structure which is able to move between a retracted configuration in which the tubular elements (21, 22, 23, 24, 25, 26) are inserted in one another, and an elongate configuration, in which two tubular elements are extracted.

The arm (1) comprises a hydraulic actuator (4), associated to the support structure (21, 22, 23, 24, 25, 26) and provided with three hydraulic elements (41, 42, 43) telescopically connected to one another, each of which is connected to a respective tubular element of the support structure.