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US 4,364,326 AGranted
Devices to control boats and other objects on moving ships
OwnerRoderick D. Pikeinventor
Life of this patent
Estimating the term…
Abstract
This invention relates to devices and methods to control the movement of boats and other objects, for example container loads, which are being moved above the deck of a ship moving in a seaway. In particular it is concerned with devices to restrain a boat or other object with respect to lateral swinging movement when suspended by a ship-mounted hoist. The invention is of particular, but by no means exclusive, application to the launch and recovery of inflatable and rigid inflatable rescue, life and work boats.
Claims5
In a device characterized as a fixed jib rotating crane, which can be mounted on the deck of a ship, which includes
- a hoist having a vertical section rotatable about a base, jib projected above said vertical section and base, pulleys and hoist wire, a crane hook attached to the end of said hoist wire from which a bridle can be suspended for attachment to a boat or other object so that the boat or other object can be raised from the deck of the ship, suspended, and lowered, the improvement comprising
- a rigid restraining structure, in combination with said hoist, located adjacent the vertical section of said hoist, which is constituted of a lower generally straight segment the terminal end of which is attached directly to said base of said hoist, and an upper part-circular shaped section the open, concave side of which presents laterally opposed locating surface portions, the lower straight segment and said concave side of said rigid restraining structure forming a surface against which the boat or other object is rested to avoid physical contact of the boat or other object with said hoist, the concave side of which can engage the side edge portion of the boat or other object to maintain horizontal location for the engaged boat or other object and keep it away from the hoist from which the boat or other object is suspended, the rigid restraining structure rotating in unison with said hoist about the rotational axis thereof to retain its engagement with said boat or other object to thereby suppress the lateral swinging movement of said boat or other object with respect to the hoist as when the ship is moving in a seaway, or the hoist rotated for lowering the boat.
In a device characterized as a luffing davit which can be mounted on the deck of a ship, the combination which comprises
- a davit arm having a longitudinally slotted vertical lower portion pivotally attached and rotatable on said deck, an upper portion which is inclined inwardly, a hoist wire and means for the attachment thereof to a boat or other object so that the boat or other object can be raised from the deck of the ship, suspended, and lowered,
- a rigid restraining arm constituted of a lower generally straight segment the terminal end of which is pivotally attached to said deck and disposed adjacent, slightly inboard of, and substantially at the same level as the attachment of said davit arm, said lower generally straight segment carrying a cross head connection affixed within the longitudinal guide slot at the lower portion of said davit arm, and slidable therein, and an upper part-circular shaped section the open, concave side of which presents laterally opposed locating surface portions which can engage the side edge portion of the boat or other object to provide horizontal location for the engaged boat or other object at least in a direction toward and away from the hoist from which the boat or other object is suspended and thereby suppress the lateral swinging movement thereof with respect to the hoist, and whereupon because of the cross-head connection which is slidable within the longitudinal guide slot at the lower portion of the davit arm provides a linkage which operates automatically to vary the height of engagement with the boat according to the angular position of the hoist, and the boat or other object is held tilted against the restraining structure as when lifted from the deck, the rigid retaining structure moving outwardly to maintain a close relationship with the boat or other object so that any unplanned movement of the latter is prevented.
Dependencies are inferred from the claim text.