Cranes and crane systems with high capacity lifting capabilities, as well as versatility and relatively large operational areas. A crane of the present disclosure may have main boom pivotable about a substantially horizontal axis and a luffing assembly configured for luffing the boom about the axis. The main boom may be pivotable in both a forward luffing operation and a reverse or rearward luffing operation. In this way, the main boom may be operable within a range extending up to 180 degrees. Various adjustment mechanisms may be used to shift the main boom from a forward luffing operation to a reverse luffing operation. Additionally, a crane of the present disclosure may have a utility boom rotatable about a substantially vertical axis. The utility boom may allow for added lateral reach of the crane, thus further increasing the operational area of the crane.

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 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 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 changing device easily and safely changes the posture of the backstop of a crane between a support posture and a storage posture. The backstop posture changing device is provided with a first support member, a second support member, a push-up mechanism, and a connection member. The first support member and the second support member are rotationally connected to a backstop and a lower boom respectively. When a cylinder rod of the push-up mechanism is extended with respect to a cylinder body, a push-up member pushes up the first support member and the posture of the backstop is changed from a storage posture on the lower boom to a support posture in which it is possible to support a boom while the crane is in a working posture.

A changing device easily and safely changes the posture of the backstop of a crane between a support posture and a storage posture. The backstop posture changing device is provided with a first support member, a second support member, a push-up mechanism, and a connection member. The first support member and the second support member are rotationally connected to a backstop and a lower boom respectively. When a cylinder rod of the push-up mechanism is extended with respect to a cylinder body, a push-up member pushes up the first support member and the posture of the backstop is changed from a storage posture on the lower boom to a support posture in which it is possible to support a boom while the crane is in a working posture.

A crane having a luffing jib and a lifting cylinder includes a cylinder body and a movable rod hinged on the jib to raise and lower the jib, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration, and further including a spacer hinged on the jib and supporting an abutment, the spacer configured for pivoting between a release position wherein the spacer is offset, authorizing the movable rod to be displaced freely, and a locking position wherein the spacer is folded so that the abutment is able to bear on the cylinder body to fixedly maintain the movable rod in the deployed holding position.

A crane includes a luffing jib and a lifting cylinder having a cylinder body and a movable rod hinged on the jib to displace the jib in lifting motion and in lowering motion, and a locking device adapted to cooperate with the lifting cylinder to mechanically lock the rod in a deployed holding position and block the jib in a raised holding configuration. The crane further includes a spacer hinged on the jib and supporting a stop, the spacer pivotable between a release position in which the spacer is shifted, allowing the movable rod to be freely displaced, and a locking position in which the spacer is folded so that the stop is capable of abutting on a bearing surface in a ball jointed connection with the cylinder body, to fixedly hold the movable rod in the deployed holding position.

A gravity actuated crane stop for a crane is disclosed. The gravity actuated crane stop has a first connector at a first end configured to couple to a first crane member and an interface at a second end configured to interface with a second crane member. A gravity actuated mechanism is disposed on the body and has a first configuration in which gravity actuated mechanism disables the interface, and a second configuration in which the gravity actuated mechanism does not disable the interface. The gravity actuated mechanism is automatically changeable from the first configuration to the second configuration as the body is moved from a first orientation relative to a horizontal plane to a second orientation relative to the horizontal plane.