The present disclosure relates to a telescopic boom for a crane, wherein the telescopic sections of the telescopic boom each comprise at least one main telescopic part and at least one additional telescopic part and wherein the main telescopic part and the additional telescopic part are arranged above one another. The disclosure further relates to a crane having a corresponding telescopic boom.

This expansion device is an expansion device that expands and contracts an boom, the expansion device including: a first hydraulic source that discharges a first working fluid; an expandable cylinder that has a fixed part and a movable part and is operated by the first working fluid; a second hydraulic source that is provided to the movable part, discharges the second working fluid, and is a separate hydraulic source from the first hydraulic source; a first connecting mechanism that is operated by the second working fluid and switches between a connected state and a disconnected state of the first boom element and the movable part; and a second connecting mechanism that is operated by the second working fluid and switches between a connected state and a disconnected state of the first boom element and the second boom element.

A boom for supporting a drilling and bolting tool includes a first portion including a first end and a second end, a longitudinal axis extending between the first end and the second end; a second portion including a proximal end and a distal end, the proximal end supported for translational movement relative to the first portion in a direction parallel to the longitudinal axis, the distal end configured to support the drilling and bolting tool; an actuator for moving the second portion relative to the first portion parallel to the longitudinal axis; and a fluid passage for conveying pressurized fluid between the first end of the first portion and the drilling and bolting tool adjacent the distal end of the second portion, the fluid passage positioned within the first portion and the second portion.

A vehicle crane having a luffable main jib and an additional jib system arranged on a free end section of the main jib and comprising a first additional jib part and a second additional jib part. To further reduce the weight of the additional jib system and the vehicle crane fitted therewith, and to permit an overall more economical mode of production, the first additional jib part has a rectangular cross-section having four longitudinal chords connected together via transverse struts or/and diagonal struts and the second additional jib part has a triangular cross-section having three longitudinal chords connected together via transverse struts, wherein the two additional jib parts are coupled, or can be coupled, together via a cross-section change adapter.

A crane, in particular a mobile crane, includes a crane jib which can be moved about a substantially horizontal luffing axis, and a tensioning device for the crane jib. The tensioning device includes two pendants which run from the jib tip to the jib base of the crane jib and tensioning posts each tensioning a respective one of the pendants relative to the crane jib in a triangular configuration. In order to operate the crane, a luffing angle of the crane jib about the luffing axis is measured or recorded, and a spread angle between the tensioning posts while the crane jib is being used is modified depending on the luffing angle.

A work machine includes: an actuator that extends and retracts a telescopic boom; an electric drive source that is provided in the actuator and drives using power supplied from a power source; an operating unit that operates based on power of the electric drive source; and a joint that has a drive-side element fixed to a first transmission shaft that rotates on the basis of the power of the electric drive source and a driven-side element fixed to a second transmission shaft connected to the operating unit, the joint being able to take a transmission state in which both the drive-side element and the driven-side element rotate and a non-transmission state in which only either the drive-side element or the driven-side element rotates.

This work machine includes: an actuator that extends and retracts a telescopic boom; an electric drive source that is provided in the actuator and drives using power supplied from a power source; an operating unit that operates based on power of the electric drive source; an electric circuit capable of switching between a drive state in which a supply of power from the power source to the electric drive source is allowed to drive the electric drive source, and a braking state in which the supply of power from the power source to the electric drive source stops to generate a braking force to be applied to the electric drive source; and a control unit that controls the switching between the drive state and the braking state.

A telescoping jib system of a mobile crane having a basic telescoping jib and an additional telescoping jib that can be retracted and extended via a telescoping cylinder with a securing and locking unit. In order to improve the telescoping jib system, it is proposed that a securing unit is arranged on a tip of the telescoping cylinder, the securing unit comprises exclusively at least one driving bolt, via which an additional telescoping jib separate from the basic telescoping jib can be retracted into the basic telescoping jib. The invention also relates to a method for lengthening a basic telescoping jib of a mobile crane by means of an additional telescoping jib to form a telescoping jib system.

A boom system includes a base assembly and a boom assembly. The boom assembly includes a boom including a plurality of boom sections. The plurality of boom sections includes a lower boom section coupled to and extending away from the base assembly and defining a proximal end of the boom and an upper boom section defining a distal end of the boom. The boom assembly further includes an attachment coupler assembly coupled to a boom section other than the upper boom section and configured to receive a first implement. The boom assembly further includes an implement connector positioned at the distal end of the boom, the implement connector configured to receive a second implement.

A telescoping jib of a mobile crane having a basic box and a plurality of inner boxes that can each be extended from a retraction position to an extension position and that can be locked and unlocked together in the respective retraction position or extension positions by means of bolting holes, which are arranged in the basic and inner boxes, and associated locking bolts. In order to provide a telescoping jib of a mobile crane which can be easily unlocked in an emergency, it is proposed that, in the retraction position of the basic and inner boxes, the bolting holes for the extension positions are aligned with one another.