A pulley system for tying a boat to an anchor comprising a block and tackle assembly and a jammer. The block and tackle assembly has a plurality of pulleys arranged on a first bracket and a second bracket, and a first rope strung sequentially through each of the pulleys, ending with a last pulley. The jammer is coupled to the second bracket and has a channel and a jammer exit at the end of the channel. The last pulley, the channel, and the jammer exit are configured to create a tortuous path for the rope through the second bracket. The channel may be misaligned with the last pulley. A swivel and a rope clip may be coupled to the block and tackle assembly. The swivel is configured to rotate at least 360 in either direction. The rope clip is configured to allow for quick tightening of the pulley system.

The tandem pulley comprises a pair of sheaves mounted in line between first and second flanges. A gate is fitted rotating with respect to the first flange between closed and open positions. The gate comes into contact with the second flange in the closed position to close a housing. The clamp is movable in rotation on the gate between a locking position locking the gate in the closed position and an unlocking position. The clamp has a prong pressing on the first flange and the gate in the locking position. The clamp has an actuating area separated from the first flange by the gate. Rotation of the actuating area from the locking position to the unlocking position corresponds to a movement of the actuating area away from the second flange. Rotation of the actuating area results in pivoting of the prong.

The tandem pulley comprises a pair of sheaves mounted in line between first and second flanges. A gate is fitted rotating with respect to the first flange between closed and open positions. The gate comes into contact with the second flange in the closed position to close a housing. The clamp is movable in rotation on the gate between a locking position locking the gate in the closed position and an unlocking position. The clamp has a prong pressing on the first flange and the gate in the locking position. The clamp has an actuating area separated from the first flange by the gate. Rotation of the actuating area from the locking position to the unlocking position corresponds to a movement of the actuating area away from the second flange. Rotation of the actuating area results in pivoting of the prong.

Provided is an auxiliary sheave device with a simple and lightweight structure and a crane including the same. The auxiliary sheave device, provided in the crane including a derrick member guy line, includes an auxiliary sheave frame and an auxiliary sheave guy line supporting the auxiliary sheave. The derrick member guy line is connected to the distal end portion of the derrick member. The auxiliary sheave frame is attached to the distal end portion of the derrick member so as to be capable of making rotational movement and taking a projecting posture of projecting in the distal end direction from the distal end portion of the derrick member. The auxiliary sheave guy line is connected to the distal end portion of the auxiliary sheave frame and a guy line connection portion of the derrick member so as to keep the auxiliary sheave frame in the projecting posture.

Provided is an auxiliary sheave device with a simple and lightweight structure and a crane including the same. The auxiliary sheave device, provided in the crane including a derrick member guy line, includes an auxiliary sheave frame and an auxiliary sheave guy line supporting the auxiliary sheave. The derrick member guy line is connected to the distal end portion of the derrick member. The auxiliary sheave frame is attached to the distal end portion of the derrick member so as to be capable of making rotational movement and taking a projecting posture of projecting in the distal end direction from the distal end portion of the derrick member. The auxiliary sheave guy line is connected to the distal end portion of the auxiliary sheave frame and a guy line connection portion of the derrick member so as to keep the auxiliary sheave frame in the projecting posture.

A vertical lifting device and method are provided. The vertical lifting device includes a fixed frame fixed to a foundation. A first cavity allowing passage of a lifting rope is provided in the middle of the fixed frame. A sliding frame moving horizontally on the fixed frame is arranged above the fixed frame. A second cavity allowing passage of the lifting rope is provided in the middle of the sliding frame. At least two stepping vehicles alternately lowering or lifting weights are arranged on the sliding frame and move on the sliding frame. The stepping vehicles are spaced in preset distances. The lifting rope penetrates through the stepping vehicles in sequence. Each stepping vehicle is provided with a clamping part clamping the lifting rope and a driving mechanism driving the stepping vehicle to move on the sliding frame.

An Enhanced Lift Assist Device is described. The device allows a user to lift and manipulate large, heavy or bulky items by applying force to the item as opposed to traditional control methods such as buttons. This force based system provides ease of movement of the item, making it appear much lighter than it actually is. The Enhanced Lift Assist Device also includes an adjustable base that allows for change of orientation of the device that may include leveling or self-leveling functionality, allowing the device to be operated in non-traditional environments that require leveling or operational adjustments for proper functioning.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

Hoists, platforms and davits are described as well as methods of securing same to telecommunication and other towers. The hoists, platforms and davits may be secured to the towers on a temporary basis using clamps. The clamps may include brackets and cables. The cables may be attached to the brackets, may wrap around the outer surface/perimeter of the tower pole/leg and may use tension to keep the bracket in place.

A pipe replacement system and cable guide frame are shown. Configurations are shown that include plurality of guide pulleys attached to the cable guide frame to define a curved path between a pipe to be replaced and a cable pulling system. Configurations are shown where a pipe breaking tool is pulled over the plurality of guide pulleys for ease of removal after a replacement operation. Configurations are also shown that include a stationary splitter adjacent to the cable pulling system to prevent jamming of the cable pulling system.