Abstract: The invention provides a lockable closure device for a closure that is adapted to selectively cover at least a portion of an opening. The lockable closure device comprises a first handle adapted for provision on one side of the closure, a second handle for provision on the opposite side of the closure, and a connection means by which the handles are pivotally connected relative to the closure such that the first handle may be disposed in a first position in which the second handle cannot be moved, and in a second position in which the second handle can be moved. There is also provided a closure having one or more of said lockable closure devices coupled thereto.

Abstract: The invention provides a rope sheave having two substantially opposed faces, each face having a plurality of ridges extending from an inner circumferential region of the face to an outer circumferential region of the face. The ridges are arranged such that those portions of the ridges on one face at the inner circumferential region substantially oppose those portions of the ridges on the opposite face at the inner circumferential region, and those portions of the ridges at the outer circumferential region on one face substantially oppose regions between those portions of the ridges at the outer circumferential region of the other face. The faces may be separable to provide two sheave parts.

Abstract: The invention provides a chain wheel part comprising a centre about which the part is adapted to rotate in use, and a plurality of chain link receiving pockets. Each pocket is shaped such that a first end of a chain link received in the pocket in use is nearer the centre of the wheel than a second end of the chain link. The invention also provides a chain wheel including two such chain wheel parts.

Abstract: A winch includes a chain wheel mounted on a spindle. A clutch is provided to selectively engage or disengage the chain wheel with the spindle. A clutch nut having a central aperture is movable rotationally and longitudinally on the spindle by way of mutually engaging threads on the spindle and central aperture. A stop is provided on the spindle to prevent longitudinal movement of the clutch nut away from the chain plates beyond a predetermined position. A carrier rotates on the spindle and rotational direction limiting structure is provided between the carrier and the spindle.

Abstract: A winch includes a chain wheel mounted on a spindle. A clutch is provided to selectively engage or disengage the chain wheel with the spindle. A clutch nut having a central aperture is movable rotationally and longitudinally on the spindle by way of mutually engaging threads on the spindle and central aperture. A stop is provided on the spindle to prevent longitudinal movement of the clutch nut away from the chain plates beyond a predetermined position. A carrier rotates on the spindle and rotational direction limiting structure is provided between the carrier and the spindle.

Abstract: A winch includes a chain wheel mounted on a spindle. A clutch is provided to selectively engage or disengage the chain wheel with the spindle. A clutch nut having a central aperture is movable rotationally and longitudinally on the spindle by way of mutually engaging threads on the spindle and central aperture. A stop is provided on the spindle to prevent longitudinal movement of the clutch nut away from the chain plates beyond a predetermined position. A carrier rotates on the spindle and rotational direction limiting structure is provided between the carrier and the spindle.

Abstract: A multispeed winch or gear box wherein an axially-movable gear located on a shaft parallel to the drive shaft is movable by operation of a lift mechanism to be in a first position in engagement with a specific gear train or in a second position out of engagement with the gear train. Further, the winch or gear box can have a gear on the drive shaft with a lip or shoulder which can retain the axially-movable gear in the upper or first position after the lift mechanism has moved the axially movable gear to the first position, and the lift mechanism has been withdrawn. This arrangement will permit the gear box or winch to automatically shift from first speed to second speed to third speed upon reversal of the drive shaft rotation.

Abstract: A multispeed winch or gear box wherein an axially-movable gear located on a shaft parallel to the drive shaft is movable by operation of a lift mechanism to be in a first position in engagement with a specific gear train or in a second position out of engagement with the said gear train. Further, the winch or gear box can have a gear on the drive shaft with a lip or shoulder which can retain the axially-movable gear in the upper or first position after the lift mechanism has moved the axially movable gear to the first position, and the lift mechanism has been withdrawn. This arrangement will permit the gear box or winch to automatically shift from first speed to second speed to third speed upon reversal of the drive shaft rotation.