The invention relates to a construction machine having a mast and a lifting element which can be moved up and down along the mast with a hoist rope. The hoist rope can be activated by means of two rope winches. At least one first rope winch is designed as a free fall winch, wherein the hoist rope can be lowered in free fall. To lower the hoist rope a controller is provided, with which the first rope winch, which is designed as a free fall winch, can be switched into a free fall mode. Meanwhile, a second rope winch is operated in force-locking manner.

Provided is a braking apparatus for braking of an electric winch of a construction machine, ensuring safe braking with much regeneration. The apparatus includes a regenerative-power generation unit, a regenerative-power receiving unit, a braking device for mechanical braking separately from the regenerative-power generation unit, and a braking control unit including a necessary-braking-capacity calculation section, a regeneration-capacity calculation section calculating a regeneration capacity, and a command section. The command section, when the regeneration capacity is not less than a necessary braking capacity, performs braking with only a regenerative action while not operating the braking device and, when the regeneration capacity is less than the necessary braking capacity, calculates an auxiliary braking force equivalent to a difference between the necessary braking capacity and the regeneration capacity and brings the braking device into braking action with the auxiliary braking force.

Provided is a braking apparatus for braking of an electric winch of a construction machine, ensuring safe braking with much regeneration. The apparatus includes a regenerative-power generation unit, a regenerative-power receiving unit, a braking device for mechanical braking separately from the regenerative-power generation unit, and a braking control unit including a necessary-braking-capacity calculation section, a regeneration-capacity calculation section calculating a regeneration capacity, and a command section. The command section, when the regeneration capacity is not less than a necessary braking capacity, performs braking with only a regenerative action while not operating the braking device and, when the regeneration capacity is less than the necessary braking capacity, calculates an auxiliary braking force equivalent to a difference between the necessary braking capacity and the regeneration capacity and brings the braking device into braking action with the auxiliary braking force.

A lift system comprises a drum that rotates about an axis, an elongate member that winds around the drum when the drum rotates in a first direction and that unwinds from the drum when the drum rotates in a second direction, a drive mechanism operable to rotate the drum, and a braking mechanism adapted to inhibit rotation of the drum. The braking mechanism includes a brake disk rotatable with the drum, a movable brake pad, and a ramp that guides movement of the movable brake pad. A method of operating the lift system comprises rotating the drum in a first direction to wind the elongate member onto the drum, rotating the drum in a second direction to unwind the elongate member from the drum, and moving the brake shoe along the ramp to thereby cause the movable brake pad to be compressed against the brake disk.

A lift system comprises a drum that rotates about an axis, an elongate member that winds around the drum when the drum rotates in a first direction and that unwinds from the drum when the drum rotates in a second direction, a drive mechanism operable to rotate the drum, and a braking mechanism adapted to inhibit rotation of the drum. The braking mechanism includes a brake disk rotatable with the drum, a movable brake pad, and a ramp that guides movement of the movable brake pad. A method of operating the lift system comprises rotating the drum in a first direction to wind the elongate member onto the drum, rotating the drum in a second direction to unwind the elongate member from the drum, and moving the brake shoe along the ramp to thereby cause the movable brake pad to be compressed against the brake disk.

An electric winch device including an electric motor that rotates a winch drum in a hoisting direction, and generates regenerative electric power when a rotation of the winch drum in a lowering direction is transmitted to the electric motor, a transmission device that transmits the rotation between the electric motor and the winch drum, a power calculating section that calculates power of the target object by freefall, and a control section that controls an operation of the transmission device. When the power calculated by the power calculating section exceeds reference electric power, the control section causes the transmission device to change the transmission rate of the rotation to a transmission rate at which the regenerative electric power generated by the electric motor is equal to or smaller than the reference electric power.

An electric winch device including an electric motor that rotates a winch drum in a hoisting direction, and generates regenerative electric power when a rotation of the winch drum in a lowering direction is transmitted to the electric motor, a transmission device that transmits the rotation between the electric motor and the winch drum, a power calculating section that calculates power of the target object by freefall, and a control section that controls an operation of the transmission device. When the power calculated by the power calculating section exceeds reference electric power, the control section causes the transmission device to change the transmission rate of the rotation to a transmission rate at which the regenerative electric power generated by the electric motor is equal to or smaller than the reference electric power.