Provided is a work machine capable of effectively discharging air from a hydraulic circuit of a winch unit capable of applying braking to a winch drum by receiving a working oil. The work machine includes: a winch unit having a winch drum, a winch motor, a cylinder portion and a clutch portion; a hydraulic sources; a braking operating unit; a brake valve; a connecting portion; and a throttle portion. The throttle portion includes an opening having an opening diameter that is set so as to hold a pressure in a positive oil chamber for generating a brake force applied to the winch drum and to discharge a working oil from the positive oil chamber.

Provided is a work machine capable of effectively discharging air from a hydraulic circuit of a winch unit capable of applying braking to a winch drum by receiving a working oil. The work machine includes: a winch unit having a winch drum, a winch motor, a cylinder portion and a clutch portion; a hydraulic sources; a braking operating unit; a brake valve; a connecting portion; and a throttle portion. The throttle portion includes an opening having an opening diameter that is set so as to hold a pressure in a positive oil chamber for generating a brake force applied to the winch drum and to discharge a working oil from the positive oil chamber.

A winch brake device that is used for a work machine and generates a braking force on the basis of a brake manipulation, includes a pressing member that brings braking members into pressure contact with each other to generate the braking force, a first brake cylinder that applies a first pressing force for bringing the braking members into pressure contact with each other to the pressing member, and a second brake cylinder that applies a second pressing force different from the first pressing force to the pressing member. The first brake cylinder and the second brake cylinder are capable of applying the first pressing force or the second pressing force independently of each other.

A winch brake device that is used for a work machine and generates a braking force on the basis of a brake manipulation, includes a pressing member that brings braking members into pressure contact with each other to generate the braking force, a first brake cylinder that applies a first pressing force for bringing the braking members into pressure contact with each other to the pressing member, and a second brake cylinder that applies a second pressing force different from the first pressing force to the pressing member. The first brake cylinder and the second brake cylinder are capable of applying the first pressing force or the second pressing force independently of each other.

The disclosed technology includes a bullwheel assembly having a wheel configured to rotate about a central axis extending through a center of the wheel and a central hub assembly attached to the wheel proximate the center of the wheel. The central hub assembly can facilitate rotation of the wheel about the central axis. A shaft can be in mechanical communication with the central hub assembly and configured to support the central hub assembly, a bullwheel support frame in mechanical communication with the shaft and configured to support the shaft, and a plurality of removeable liners attached to the wheel and disposed along an outer circumferential surface of the wheel. Each removeable liner of the plurality of removeable liners can have a groove formed therein. The groove can be configured to receive and support various sizes of electrical utility lines.

The disclosed technology includes a bullwheel assembly having a wheel configured to rotate about a central axis extending through a center of the wheel and a central hub assembly attached to the wheel proximate the center of the wheel. The central hub assembly can facilitate rotation of the wheel about the central axis. A shaft can be in mechanical communication with the central hub assembly and configured to support the central hub assembly, a bullwheel support frame in mechanical communication with the shaft and configured to support the shaft, and a plurality of removeable liners attached to the wheel and disposed along an outer circumferential surface of the wheel. Each removeable liner of the plurality of removeable liners can have a groove formed therein. The groove can be configured to receive and support various sizes of electrical utility lines.

A hydraulic system for powering a winch assembly of a work machine includes a hydraulic reservoir, a pump, a cooling system, a first path of travel, and a second path of travel. The first path of travel is disposed between the pump and the cooling system, and the winch assembly is powered by the hydraulic fluid moving along the first path of travel. The second path of travel is disposed between the pump and the cooling system. When the winch assembly is in an active condition, a first valve is in an open position such that the hydraulic fluid moves along the first path of travel and through the cooling system. When the winch assembly is in an idle condition, a second valve is in an open position such that the hydraulic fluid moves along the second path of travel and through the cooling system.

A hydraulic system for powering a winch assembly of a work machine includes a hydraulic reservoir, a pump, a cooling system, a first path of travel, and a second path of travel. The first path of travel is disposed between the pump and the cooling system, and the winch assembly is powered by the hydraulic fluid moving along the first path of travel. The second path of travel is disposed between the pump and the cooling system. When the winch assembly is in an active condition, a first valve is in an open position such that the hydraulic fluid moves along the first path of travel and through the cooling system. When the winch assembly is in an idle condition, a second valve is in an open position such that the hydraulic fluid moves along the second path of travel and through the cooling system.

The present invention relates to a free-fall winch comprising a drum which can be rotatorily driven by a winch drive via a transmission and can be retained by a holding brake, wherein in addition to the holding brake a free-fall brake is provided for slowing down the drum in free-fall operation. According to the invention, the free-fall brake is arranged between winch drive and holding brake on the one hand and drum on the other hand such that when the free-fall brake is open, the drum is decoupled from the winch drive and from the holding brake and can be rotated at idle with respect to the winch drive and the holding brake.

A hydraulically actuated liftable and lowerable hook of a crane has a hydraulic system comprises at least one working machine with a hydraulic motor driving a winch. At least one drive machine comprising a pump is connected directly or indirectly to at least one of the working machines by means of two connections via corresponding working lines, which serve as a feed or return depending on the operating state of the working machine. A lowering brake valve is provided in one working line and is connected to the other working line via a control line such that the lowering brake valve is displaceable against a restoring force by pressure, which prevails in the other working line and is forwarded via the control line, from the blocking position of said valve into a through-flow position for lowering the hook by means of a primary winch.