Provided is a crane (1) comprising: a boom (7) capable of being raised, lowered, and telescoped; a wire rope (8) being suspended from the boom (7); a winch (9) for winding and unwinding the wire rope (8); and a hook (10) being raised and lowered by the winding and unwinding of the wire rope (8). The crane further comprises a spooling operation instrument (24) for enabling commanding an operation state of the winch (9). When the hook (10) is raised to a height at which the hanging length d is a prescribed value by an operation of the spooling operation instrument (24), the boom (7) is raised and extended while the wire rope (8) is unwound such that the prescribed hanging length d is maintained, thereby sustaining the elevation operation of the hook (10).

Provided is a crane (1) comprising: a boom (7) capable of being raised, lowered, and telescoped; a wire rope (8) being suspended from the boom (7); a winch (9) for winding and unwinding the wire rope (8); and a hook (10) being raised and lowered by the winding and unwinding of the wire rope (8). The crane further comprises a spooling operation instrument (24) for enabling commanding an operation state of the winch (9). When the hook (10) is raised to a height at which the hanging length d is a prescribed value by an operation of the spooling operation instrument (24), the boom (7) is raised and extended while the wire rope (8) is unwound such that the prescribed hanging length d is maintained, thereby sustaining the elevation operation of the hook (10).

Attachments for a clamping device can be used to increase the contact area between the jaws and the object to allow the clamping device to handle irregular objects, such as non-flat panels of metal, granite, ceramic, glass, quartz, or concrete plates. The attachments can include plate assemblies to be attached to the sides of the irregular objects. The attachments can include jaw plate assemblies to be attached to the sides of the jaws of the clamping device.

Attachments for a clamping device can be used to increase the contact area between the jaws and the object to allow the clamping device to handle irregular objects, such as non-flat panels of metal, granite, ceramic, glass, quartz, or concrete plates. The attachments can include plate assemblies to be attached to the sides of the irregular objects. The attachments can include jaw plate assemblies to be attached to the sides of the jaws of the clamping device.

A clamping device includes a rotatable element disposed between a jaw and a jaw support. The rotatable element has a slanting surface, interfacing a roller, and thus is configured to push the jaw toward an opposite jaw of the clamping device when rolling in a clamping direction. An auto lock mechanism is included in the clamping device, which can secure the rotating element for keeping the jaws separated. The auto lock mechanism can be activated or deactivated when the jaws are separated at a maximum or near maximum separation.

A clamping device includes a rotatable element disposed between a jaw and a jaw support. The rotatable element has a slanting surface, interfacing a roller, and thus is configured to push the jaw toward an opposite jaw of the clamping device when rolling in a clamping direction. An auto lock mechanism is included in the clamping device, which can secure the rotating element for keeping the jaws separated. The auto lock mechanism can be activated or deactivated when the jaws are separated at a maximum or near maximum separation.

Provided is a crane (1) comprising: a boom (7) capable of being raised, lowered, and telescoped; a wire rope (8) being suspended from the boom (7); a winch (9) for winding and unwinding the wire rope (8); and a hook (10) being raised and lowered by the winding and unwinding of the wire rope (8). The crane further comprises a spooling operation instrument (24) for enabling commanding an operation state of the winch (9). When the hook (10) is raised to a height at which the hanging length d is a prescribed value by an operation of the spooling operation instrument (24), the boom (7) is raised and extended while the wire rope (8) is unwound such that the prescribed hanging length d is maintained, thereby sustaining the elevation operation of the hook (10).

Provided is a crane (1) comprising: a boom (7) capable of being raised, lowered, and telescoped; a wire rope (8) being suspended from the boom (7); a winch (9) for winding and unwinding the wire rope (8); and a hook (10) being raised and lowered by the winding and unwinding of the wire rope (8). The crane further comprises a spooling operation instrument (24) for enabling commanding an operation state of the winch (9). When the hook (10) is raised to a height at which the hanging length d is a prescribed value by an operation of the spooling operation instrument (24), the boom (7) is raised and extended while the wire rope (8) is unwound such that the prescribed hanging length d is maintained, thereby sustaining the elevation operation of the hook (10).

A clamping device for lifting and transferring objects can employ slanting interfaces to convert a pulling action on the clamping device to a clamping action on the object. A pulling element in the form of a triangle can be disposed between a jaw and a jaw support of the clamping device. When the pulling element is pulled up, the base of the triangle shape pulling element can exert a force on the jaw against the jaw support, for securing a gripping action on the object.

A clamping device includes a rotatable element disposed between a jaw and a jaw support. The rotatable element has a slanting surface, interfacing a roller, and thus is configured to push the jaw toward an opposite jaw of the clamping device when rolling in a clamping direction. An auto lock mechanism is included in the clamping device, which can secure the rotating element for keeping the jaws separated. The auto lock mechanism can be activated or deactivated when the jaws are separated at a maximum or near maximum separation.