A locking head assembly (210) for a telescoping boom (118) of a crane (110) includes a locking head (212) having a base (218), an operating plate (220) operably coupled to the base, one or more cylinder pins (222) and/or one or more section lock arms (226) movable in response to movement of the operating plate relative to the base. An actuator (214) is operably coupled to the operating plate and configured to move the operating plate relative to the base. The actuator includes a motor (234) and a drive arm (236). The motor is configured to drive the drive arm between a drive arm first position and a drive arm second position. A motion mitigator (216) is connected to the actuator and the locking head and includes a housing (238), a rod (240) movable relative to the housing, and a biasing device (242) disposed between the rod and the housing.

This work machine comprises: a telescoping actuator that moves a first boom with respect to a second boom; an electrical drive source that is disposed in a movable portion of the telescoping actuator; a first biasing mechanism that maintains the connection state between the telescoping actuator and the first boom; a first connection mechanism that switches the connection state between the telescoping actuator and the first boom on the basis of the power of the electrical drive source; a second biasing mechanism that maintains the connection state between the first boom and the second boom; a second connection mechanism that switches the connection state between the first boom and the second boom on the basis of the power of the electrical drive source; and a clutch that discretionally intermittently transmits the power of the electrical drive source to the first connection mechanism and the second connection mechanism.

A hydraulic system for controlling bleed down and retraction of a boom within a safety envelope includes a backup battery power supply, and at least a first boom lift hydraulic cylinder configured to raise and lower the boom. The first boom lift hydraulic cylinder includes a solenoid bleed valve electrically connected to the backup battery power supply. The hydraulic system also includes an input device controllable by an operator of the boom. The input device may, for instance, be used by the operator to initiate bleed down and retraction of the boom from an elevated position. To accommodate independent failsafe features of the system, the input device is configured to selectively actuate the solenoid bleed valve using electrical power supplied from the backup battery power supply.

A foldable boom for conveying an item, said foldable boom being foldable about at least one folding axis, said foldable boom being locatable in a folded stowed position, and moveable to unfolded extended positions; said foldable boom having a near end arranged for pivotal movement about a first horizontal axis located on a turret, said turret being rotatable about a vertical axis; said foldable boom having first conveying apparatus to convey an item therealong, internally within said foldable boom, to a remote end of the foldable boom; wherein said foldable boom is foldable about a folding axis, and a pivoting shuttle equipped with a clamp to releasably hold an item is provided at said folding axis to transfer said item between said first conveying apparatus in boom elements connected about said folding axis.

This crane is provided with: a telescopic boom that can be extended; an extension device for extending the telescopic boom; a hydraulic pressure source provided in the extension device; a cylinder connection mechanism connected to the hydraulic pressure source and switching between the states of connection and non-connection with the telescopic boom on the basis of the supply and discharge of hydraulic oil; a first oil path for connecting the hydraulic pressure source and the cylinder connection mechanism; a first valve that is provided on the first oil path and switches the supply and discharge state of the hydraulic oil with respect to the cylinder connection mechanism; and a second oil path that bypasses the first valve and connects the hydraulic pressure source and the cylinder connection mechanism.

A hydraulic crane comprising: —a rotatable column (7); —a crane boom system (10) comprising two or more liftable and lowerable crane booms (11, 13); and—an electronic control device (25), which is configured to prevent an execution of crane boom movements that would make the lifting moment of the crane exceed the maximum allowed lifting moment of the crane, and to continuously establish position information as to the prevailing position of the load suspension point (P) of the crane boom system. When the lifting moment of the crane has reached a limit value at a given level below the maximum allowed lifting moment, the electronic control device is configured to prevent the execution of any combination of crane boom movements that would increase the horizontal distance between the load suspension point and said vertical axis of rotation and at the same time allow the execution of any combination of crane boom movements that keeps said horizontal distance unchanged or reduces said horizontal distance.

A telescoping boom includes a boom actuator having a fixed part and a movable part, the movable part configured to move along a length the fixed part, a rotary actuator operably connected to the movable part and configured to rotate relative to the movable part, a coupling pin connected to and configured to rotate with the rotary actuator, and a telescoping boom having a plurality of boom sections including a base section and one or more telescoping sections configured for telescoping movement along a longitudinal boom axis relative to the base section. A rotary extension and locking system is mounted on at least one telescoping section and is configured for selective coupling to the boom actuator and selective locking with a nearest outwardly adjacent boom section.

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 and a support member positioned within the inner volume. The boom assembly also includes a power track positioned within the inner volume that includes a plurality of movable links and a supported portion that interfaces with the support member. The push tube includes a second end portion opposite the first end portion of the push tube. The second end portion of the push tube is directly coupled to the base boom section.

The present disclosure provides a lifting device comprising: a telescopic boom, comprising a basic section, at least one primary telescopic section and at least one secondary telescopic section; a telescopic control mechanism, comprising a primary telescopic drive mechanism that controls synchronous telescoping of the at least one primary telescopic section and a secondary telescopic drive mechanism that controls synchronous telescoping of the at least one secondary telescopic section; a torque limiter, comprising a first length sensor and a second length sensor, wherein a first sensor body and a telescopic end of a first length measuring cable of the first length sensor are respectively connected to tails of adjacent two section in the basic section and the at least one primary telescopic section; and a second sensor body and a telescopic end of a second length measuring cable of the second length sensor are respectively connected to tails of adjacent two section in the primary telescopic section adjacent to the at least one secondary telescopic section and the at least one secondary telescopic section. The lifting device of the present disclosure can reduce the length of the length measuring cable of a length sensor and thus reduce its volume and weight.

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.