This crane is configured by being provided with: a telescopic boom having an inside boom element and an outside boom element that overlap each other in an extendable and contractible manner; an extension/contraction actuator that displaces one boom element among the inside boom element and the outside boom element in the extending and contracting directions; at least one electric drive source provided in the extension/contraction actuator; a first coupling mechanism that operates on the basis of power from the electric drive source and that switches between the coupled state and the uncoupled state of the extension/contraction actuator and one of the boom elements; and a second coupling mechanism that operates on the basis of power from the electric drive source and that switches between the coupled state and the uncoupled state of the inside boom element and the outside boom element.

The work machine includes: a telescoping actuator that moves a first boom in the telescoping direction with respect to a second boom; an electrical drive source that is disposed in a movable portion of the telescoping actuator; a first connection mechanism that switches a connection state between the telescoping actuator and the first boom on the basis of the power of the electrical drive source; a second connection mechanism that switches a connection state between the first boom and the second boom on the basis of the power of the electrical drive source; and a torque limiter that is disposed between the electrical drive source and the first connection mechanism or the second connection mechanism, the torque limiter maintaining, at a predetermined value or less, a load acting on a mechanical element constituting a power transmission path from the electrical drive source.

A telescopic pipe includes a base pipe having a base inner pipe rotated by external force, and a base outer pipe arranged to receive the base inner pipe; a connecting pipe having a connecting inner pipe coupled to the base inner pipe to be extendable to transfer rotational force, and a connecting outer pipe screw-coupled to the inner circumferential surface of the base outer pipe to be extendable; and a finishing pipe including a finishing inner pipe coupled to the connecting inner pipe to be extendable and to be rotated, and a finishing outer pipe that is interlocked by means of rotation of the finishing inner pipe and is screw-coupled to the inner circumferential surface of the connecting outer-pipe to be extendable, wherein the connecting outer pipe is interlocked by the rotational force of the extended finishing outer pipe and thus is extended and retracted along the base outer pipe.

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.

Telescoping boom systems, devices, and methods are provided in accordance with various embodiments. For example, some embodiments include zero dead band telescoping boom systems, devices, and methods. Embodiments in general include hard stop preloading mechanisms for telescoping booms with multiple tube segments. Some embodiments provide components that facilitate the deployment sequencing of the multiple tube segments along with facilitating preloading of the multiple tube segments of a telescoping boom. The tools and techniques provided may be integrated into the multiple tube segments rather than being provided as a separate system. Some embodiments allow for precise deployment of the multiple tube segments of the telescoping boom systems, devices, and methods.

A crane has telescoping boom, a boom actuator system and a control system. The telescoping boom includes base section and telescoping sections. The boom actuator system includes a telescoping member and a locking head on the telescoping member, the locking head having pinning members configured to selectively interact with the telescoping sections. The control system is configured to receive parameter information relating to the boom actuator system and control the boom actuator system to perform an actuator operation using the parameter information. The actuator operation is performed to move a pinning member to a selected position. The control system is further configured to determine whether the pinning member is in the selected position using the parameter information, and to control the boom actuator system to perform an actuator operation to adjust the telescoping member if the control system determines the pinning member is not in the selected position.

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.

A balanced cantilevered feeding apparatus for coupling with a jib, and a complementary method for its operation, configured to facilitate depositing and removing of a load through an opening in a building. The apparatus includes two spaced apart upright hoisting assemblies disposed on the jib, and a fly beam hoisted, balanced, and selectively positioned along a lateral axis by the two hoisting assemblies. A load securing member is mounted on a cantilevered extension portion of the fly beam, wherein the member extends beyond one of the two hoisting assemblies toward the building, and a counterweight is connected to the fly beam in the vicinity of another of the two hoisting assemblies.

A telescoping jib of a mobile crane includes sections that telescope out of a jib housing from a transport position into an operating position. A guying system has successively connected tension rods extending from the jib housing to at least one of the extended telescoping jibs by at least one guying support. The mobile crane provides a lighter construction and improved road handling, and an increased load capacity for unchanged telescoping jib measurements. To this end, a guide holder arranged on the jib housing receives the tension rods in the transport position and, in the operating position, at least one movable tension rod on one of the guying supports is respectively securely connected to the outer end of a telescoping section head in an articulated manner and can be secured to a holding mechanism on the opposite end on an adjacent guying support of an adjacent telescoping section head.