A bell design crown block for a top mounted compensator includes a removable, tilting sheave block mounted within the outside perimeter of a crown block yoke. An actuator installed in the crown block actuates the tilt function. No hinge adaptor is required and the sheave block does not hang past or below the crown block yoke. When used in a floating platform application, idler sheaves are mounted on the crown block yoke and an optional interface beam may be provided for the active heave cylinder head.

In at least one illustrative embodiment, a winch may include first and second end frames, a drum coupled between the first and second end frames and configured to rotate to wind or unwind a cable, a brake configured to resist rotation of the drum when engaged, a switch configured to cause the brake to engage the drum when the switch is activated, a slack arm frame having a first end engaged with the cable and a second end pivotally coupled between the first and second end frames, where the slack arm frame is configured to pivot between a first position when the cable is taut and a second position when the cable is slack, and a cam coupled to the slack arm frame and configured to rotate with the slack arm frame to activate the switch when the slack arm frame is in the second position.

In at least one illustrative embodiment, a winch may include first and second end frames, a drum coupled between the first and second end frames and configured to rotate to wind or unwind a cable, a brake configured to resist rotation of the drum when engaged, a switch configured to cause the brake to engage the drum when the switch is activated, a slack arm frame having a first end engaged with the cable and a second end pivotally coupled between the first and second end frames, where the slack arm frame is configured to pivot between a first position when the cable is taut and a second position when the cable is slack, and a cam coupled to the slack arm frame and configured to rotate with the slack arm frame to activate the switch when the slack arm frame is in the second position.

A method for operating a winch and an electric drive for driving a winch including a rotatable winch drum for spooling a spoolable medium and an electric motor operably coupled to the winch drum, the electric drive being configured to drive the winch drum by driving the electric motor such that a tension of the spoolable medium reaches a predetermined tension set point value or value range, and set a driving speed of the electric motor to zero, and after the setting of the driving speed of the electric motor to zero, drive the electric motor to alternate directions of rotation at predetermined driving speeds such that the direction of rotation is changed at a predetermined frequency.

An affordable tension device for maintaining tension on a wire rope of a cable-based lifting system is provided. The tension device has an elongated casting weight adapted to govern the casting weight as it rides along a predetermined wire rope for maintaining tension thereon. The tension device provides a clevis with a sheave for operatively associating with the tension wire rope.

An affordable tension device for maintaining tension on a wire rope of a cable-based lifting system is provided. The tension device has an elongated casting weight adapted to govern the casting weight as it rides along a predetermined wire rope for maintaining tension thereon. The tension device provides a clevis with a sheave for operatively associating with the tension wire rope.

A reactive tether spool comprises a drum, a signal cable, a drum actuator, a tension sensor, and a controller. The signal cable transports power and a control signal to a UAV. A controller receives a tension measurement from the tension sensor and controls the drum actuator to maintain a determined tension on the signal cable while performing at least one of the following: dispensing the signal cable; holding the signal cable steady; and collecting the signal cable.

A fairlead for use with a winch is disclosed. The fairlead is made up of a first and second roller, a motor, a sensor, and a controller. The rollers are adapted to aid in spooling or unspooling a line. The motor drives at least the first roller. The sensor determines whether a winch drum is spooling or unspooling a line. The controller is connected to the motor and communicates with the sensor. The sensor determines whether the winch drum is spooling or unspooling the line. The controller is configured to direct the motor so that the rollers assist in unspooling or spooling the line in coordination with the winch drum. In some embodiments, the fairlead is integrated into the winch.

Example string reels with level wind apparatus are disclosed herein. An example level wind apparatus includes a guide to direct a line onto or away from a reel when the reel is rotating. The reel is rotatable in a first direction to wind the line onto the reel and the reel is rotatable in a second direction to unwind the line from the reel. The level wind apparatus also includes a tensioner to create tension in the line while the reel is rotating the second direction.

Example string reels with level wind apparatus are disclosed herein. An example level wind apparatus includes a guide to direct a line onto or away from a reel when the reel is rotating. The reel is rotatable in a first direction to wind the line onto the reel and the reel is rotatable in a second direction to unwind the line from the reel. The level wind apparatus also includes a tensioner to create tension in the line while the reel is rotating the second direction.