A back stop for a crane which eliminates operator's discomfort and adverse effects on surrounding environment due to generation of abnormal noise and enables greasing work to be facilitated. A back stop includes an outer casing having a base end portion turnably connected to a boom or a crane main body and an opening portion opened in the outer casing front end portion; an inner casing having a base end portion turnably connected to the crane main body or the boom and having a front end portion side slidably fitted into the outer case through the opening portion; and a greasing tube arranged in the outer casing or the inner casing. An inlet of the greasing tube is arranged outside of the outer casing or outside of the inner casing on the base end portion side on which the greasing tube is arranged. A discharge port of the greasing tube is attached to a front end portion of the inner casing.

A compressible stop for use in a crane has a housing, a rod slidably mounted within the housing, a floating piston, and a valve assembly. The floating piston divides the housing into a gas portion biasing the floating piston towards an end of the housing and a liquid portion containing a hydraulic fluid. The valve assembly divides the liquid portion into a support portion and a reserve portion. The valve assembly includes a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion unless the pressure is above a threshold pressure, and a frangible divider configured to rupture when the liquid pressure exceeds a rupture pressure.

A compressible stop for use in a crane has a housing, a rod slidably mounted within the housing, a floating piston, and a valve assembly. The floating piston divides the housing into a gas portion biasing the floating piston towards an end of the housing and a liquid portion containing a hydraulic fluid. The valve assembly divides the liquid portion into a support portion and a reserve portion. The valve assembly includes a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion unless the pressure is above a threshold pressure, and a frangible divider configured to rupture when the liquid pressure exceeds a rupture pressure.

A compressible stop for use in a crane has a housing, a rod slidably mounted within the housing, a floating piston, and a valve assembly. The floating piston divides the housing into a gas portion biasing the floating piston towards an end of the housing and a liquid portion containing a hydraulic fluid. The valve assembly divides the liquid portion into a support portion and a reserve portion. The valve assembly includes a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion unless the pressure is above a threshold pressure, and a frangible divider configured to rupture when the liquid pressure exceeds a rupture pressure.

A compressible stop for use in a crane has a housing, a rod slidably mounted within the housing, a floating piston, and a valve assembly. The floating piston divides the housing into a gas portion biasing the floating piston towards an end of the housing and a liquid portion containing a hydraulic fluid. The valve assembly divides the liquid portion into a support portion and a reserve portion. The valve assembly includes a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion unless the pressure is above a threshold pressure, and a frangible divider configured to rupture when the liquid pressure exceeds a rupture pressure.

There is provided a crane including a front member capable of derricking, a backstop disposed on a rear surface side of the front member so as to limit a standing operation of the front member, an angle sensor that detects an angle of the front member, an operation detection unit that detects whether or not the backstop is operated, and a controller that controls a derricking operation of the front member. In a case where the controller determines that the angle of the front member is equal to or larger than a predetermined angle, based on a detection signal output from the angle sensor, and determines that the backstop is not operated, based on a detection signal output from the operation detection unit, the controller stops the standing operation of the front member.

There is provided a crane including a front member capable of derricking, a backstop disposed on a rear surface side of the front member so as to limit a standing operation of the front member, an angle sensor that detects an angle of the front member, an operation detection unit that detects whether or not the backstop is operated, and a controller that controls a derricking operation of the front member. In a case where the controller determines that the angle of the front member is equal to or larger than a predetermined angle, based on a detection signal output from the angle sensor, and determines that the backstop is not operated, based on a detection signal output from the operation detection unit, the controller stops the standing operation of the front member.

Method and apparatus for a portable hoisting system having an upright gin pole which is attached to the upright standing very tall pole or tower using a plurality of straps. Extending away from the gin pole is an angularly adjustable arm which is user selectable to be either; e.g., at a 90-degree angle or a 45-degree angle, which arm is supported by a brace connected between the extension arm and the upright gin pole. The gin pole is hollow on its inside which allows a load line to travel through the interior of the gin pole from its lower end to its upper outlet end and includes a plurality of pulleys which allow the load line to travel through the inside of the hoisting system. Also included is a heel block or the like wherein one end of the load line is connected to a capstand hoist disposed on the front or rear end of a vehicle and a ball with hook for supporting a load. Also included optionally is a tag line connected to the load line and being held by a ground member for helping to control the movement of the load.

The invention relates to a crane comprising a tower and a jib, wherein the jib rests on the tower and is fixed on the tower when the crane is in an inoperative position.

The invention relates to a crane comprising a tower and a jib, wherein the jib rests on the tower and is fixed on the tower when the crane is in an inoperative position.