A method for assembling a crane that comprises erecting an upright ballast mast with a back mast top slide that is movable along the ballast mast and constructing a back mast using the upright ballast mast. This comprises the steps of providing a back mast upper section, multiple back mast intermediate sections, and a back mast lower section. The method also comprises connecting a part of the back mast including at least the back mast upper section, and possibly further including one or more pre-connected intermediate sections, to the back mast top slide. The part of the back mast that has been connected to the back mast top slide is stepwise extended by attaching further back mast intermediate sections and the back mast lower section. During the extension of the back mast the back mast top slide is stepwise raised along the upright ballast mast.

A portable hoist assembly for lifting, relocating and lowering loads includes a trailer that is both wheeled and configured to couple to a vehicle. A power module, a lift arm and an actuator are coupled to the trailer. The actuator is operationally coupled to the power module and the lift arm. A fastener is operationally coupled proximate to a second end of the lift arm. The fastener is configured to couple the lift arm to a load. The actuator is positioned to motivate the lift arm and the fastener upwardly and downwardly. The load that is coupled to the lift arm is elevated from a first resting position to a raised position, repositioned by movement of the trailer, and lowered from the raised position to a second resting position.

The invention relates to an electro-hydraulic device for moving a jib for a tower crane, in which device the motor of the hydraulic unit is switched off when the position of the jib is not altered for a predetermined time period.

The invention relates to an electro-hydraulic device for moving a jib for a tower crane, in which device the motor of the hydraulic unit is switched off when the position of the jib is not altered for a predetermined time period.

The disclosure relates to a crane comprising an undercarriage, a uppercarriage mounted rotatably on the undercarriage, a boom connected to the uppercarriage, a derrick boom connected to the uppercarriage, via which the boom is braced, a guide connected to the uppercarriage, and a derrick ballast comprising at least two ballast elements that can be stacked on top of one another and a cross member, which is connected to the derrick boom via a ballast bracing and to the uppercarriage via the guide. The cross member can be connected to a stack of ballast elements via a retaining element comprising first connecting means for releasably connecting the retaining element to second connecting means of the ballast elements of the stack. The retaining element can be connected to a partial stack of ballast elements of the stack by moving the retaining element and/or the cross member relative to the uncoupled stack.

The disclosure relates to a crane comprising an undercarriage, a uppercarriage mounted rotatably on the undercarriage, a boom connected to the uppercarriage, a derrick boom connected to the uppercarriage, via which the boom is braced, a guide connected to the uppercarriage, and a derrick ballast comprising at least two ballast elements that can be stacked on top of one another and a cross member, which is connected to the derrick boom via a ballast bracing and to the uppercarriage via the guide. The cross member can be connected to a stack of ballast elements via a retaining element comprising first connecting means for releasably connecting the retaining element to second connecting means of the ballast elements of the stack. The retaining element can be connected to a partial stack of ballast elements of the stack by moving the retaining element and/or the cross member relative to the uncoupled stack.

A davit (10) for arresting the fall of a person working at heights or for material handling where lifting of overloaded material is prevented, has a mast (12), a fuse holder (14) at the top of mast, a fuse head (16) connected to the fuse holder and having sacrificial fuses (18) arranged in series thereon, a jib arm (20) connected to the fuse head, and a primary fall arrestor system (22) having an arresting load limit and mounted to a side of the mast if the davit is to be used for arresting the fall of a person (25) working at heights, and/or a primary lifting-overload prevention system having a working load limit and safety factors if the davit is to be used for material handling where lifting of overloaded material (78) is to be prevented. When excessive forces are being absorbed either by the primary fall arrestor system or by the primary lifting-overload prevention system, the fuse head rotates downwardly relative to the fuse holder, and causes the breaking of one or progressively more of the sacrificial fuses until enough fuses have been broken to absorb the excessive forces.

A telescoping barrier assembly provides interlocking modules coupled together so as to slide vertically with respect to the other. The modules telescopically extend to a deployed position to form a barrier that withstands inertial and the external forces, and then retracts to a collapsed position. The modules include a base module and a plurality of deployable modules that are arranged in a nested configuration, such that each module slides in and out of an adjacent module. The base module has a mounting portion that may be subterranean. A lifting mechanism applies an axial force to the deployable modules to enable displacement between the operational and collapsed position. Spring biased lateral support members help the deployable modules remain in the extended position and a pulley system helps displace the modules to the collapsed position. An inner and outer seal inhibit liquid leakage between the module and between multiple adjacent assemblies.

This automatic unfolding and folding tower crane comprises a mast and a jib which are movable between an operation configuration and a transport configuration.

The mast has a first mast section (2.1) and a second mast section (2.2). The jib has a first jib section (4.1) and a second (4.2) jib section. The first jib section (4.1) has an upper limit (4.11) and a lower limit (4.12) defining a height (H4.1) of the first jib section (4.1). The first mast section (2.1) is rotatably connected to the first jib section (4.1) about a hinge axis (Y24).

The jib direction (X4) is shifted with respect to the mast direction (Z2) parallel to the hinge axis (Y24). A distance between the hinge axis (Y24) and the lower limit (4.12) is greater than 75% of the height (H4.1) of the first jib section (4.1).

This automatic unfolding and folding tower crane comprises a mast and a jib which are movable between an operation configuration and a transport configuration.

The mast has a first mast section (2.1) and a second mast section (2.2). The jib has a first jib section (4.1) and a second (4.2) jib section. The first jib section (4.1) has an upper limit (4.11) and a lower limit (4.12) defining a height (H4.1) of the first jib section (4.1). The first mast section (2.1) is rotatably connected to the first jib section (4.1) about a hinge axis (Y24).

The jib direction (X4) is shifted with respect to the mast direction (Z2) parallel to the hinge axis (Y24). A distance between the hinge axis (Y24) and the lower limit (4.12) is greater than 75% of the height (H4.1) of the first jib section (4.1).