System to transfer cargo or passengers between platforms while undergoing relative motion

Claim 1

Apparatus to control the rate of closure or separation and the landing site for cargo or personnel during transfer between first and second platforms while subject to vertical or lateral motion, one with respect to the other, said apparatus including the combination of: a constant tension winch on said first platform, said constant tension winch including means to establish a first constant tension level in the winch cable extending from said first platform, a variable constant tension winch on said second platform, said variable constant tension winch including means to establish second and third constant tension levels in the winch cable extending from said second platform, said second constant tension level being essentially less than said first constant tension level and said third constant tension level being essentially greater than said first constant tension level, engagement means to connect together the cables of said constant tension winch and said variable constant tension winch, carrier means coupled for movement by said cables while connected together by said engagement means, and control means operative to select one of said second and third constant tension levels for establishing the direction of movement of said carrier means between said first platform and said second platform by the relative tension differential between said first constant tension level and the selected second or third constant tension level.

Claim 8

A method for controlling the rate of closure or separation and the landing site of a carrier for cargo or personnel during transfer from a lifting platform onto a landing platform while said platforms are subject one with respect to the other to vertical and/or lateral movement due to waves and/or wind within an envelope of motion, said method including the steps of: lowering said carrier by the cable of a lifting winch on said lifting platform to an elevation spaced above said landing platform to inhibit contact therewith while said platforms move one with respect to the other pursuant to said envelope of motion, coupling the cable of a downhaul winch on said landing platform to the cable of the lifting winch, eliminating slack in the coupled cables by energizing the downhaul winch while the carrier and landing plaftorms approach each other pursuant to said envelope of motion, energizing said lifting winch to impose a preestablished first constant tension level in the coupled cables to maintain the carrier at a fixed distance above the landing platform, said lifting winch at the preestablished first constant tension level having a wind-up velocity above a prescribed minimum take-up velocity precluding cable slack while said platforms move one with respect to the other pursuant to said envelope of motion, and energizing said downhaul winch to impose a preestablished second constant tension level greater than said first constant tension level and at a controllable wind-up speed on the coupled cables to move the carrier onto the landing platform at a desired rate of closure for landing and support of the carrier on the landing platform.

Claim 9

A method for controlling the rate of closure or separation and the landing site of a carrier for cargo or personnel during transfer from a lifting platform onto a landing platform while said platforms are subject one with respect to the other to vertical and/or lateral movement due to waves and/or wind within an envelope of motion, said method including the steps of: lowering said carrier by the cable of a lifting winch on said lifting platform to an elevation spaced above said landing platform to inhibit contact therewith while said platforms move one with respect to the other pursuant to said envelope of motion, coupling the cable of a downhaul winch on said landing platform to the cable of the lifting winch, eliminating slack in the coupled cables by energizing the downhaul winch while the carrier and landing plaftorms approach each other pursuant to said envelope of motion, energizing said lifting winch to impose a preestablished first constant tension level in the coupled cables to maintain the carrier at a fixed distance above the landing platform, said lifting winch at the preestablished first constant tension level having a wind-up velocity above a prescribed minimum take-up velocity precluding cable slack while said platforms move one with respect to the other pursuant to said envelope of motion, and energizing said downhaul winch to impose a preestablished second constant tension level greater than said first constant tension level and at a controllable wind-up speed on the coupled cables to move the carrier onto the landing platform at a desired rate of closure for landing and support of the carrier on the landing platform.

Claim 12

A method for controlling the rate of closure or separation and the landing site of a carrier for cargo or personnel during transfer from a landing platform onto a lifting platform while said platforms are subject one with respect to the other to vertical and/or lateral movement due to waves and/or wind within an envelope of motion, said method including the steps of: paying out the cable of a lifting winch on said lifting platform to an elevation for access thereto from said landing platform while said platforms move one with respect to the other pursuant to said envelope of motion, said lifting winch having means to preestablish a first constant tension level in the cable thereof, coupling the cable of a downhaul winch on said landing platform to the cable of the lifting winch, said downhaul winch having means to select one of preestablished second and third constant tension levels in the cable thereof, said second constant tension level being less than said first constant tension level and said third constant tension level being greater than said first constant tension level, imposing the said third constant tension level on the coupled cables by energizing the downhaul winch to maintain the carrier on the landing platform, eliminating slack in the coupled cables by energizing the lifting winch while the carrier and lifting platforms approach each other pursuant to said envelope of motion, energizing said lifting winch to impose the preestablished first constant tension level in the coupled cables to maintain the carrier on the landing platform through continued relative motion pursuant to said envelope of motion, said lifting winch at the preestablished first constant tension level having a wind-up velocity above a prescribed minimum take-up velocity precluding cable slack while said platforms move one with respect to the other, energizing said downhaul winch to impose said preestablished second constant tension level which is less than said first constant tension level and at a controllable wind-up speed on the coupled cables to move the carrier from the landing platform when the carrier recedes away from the lifting platform, and maintaining the cable take-up velocity by the lifting winch at a value exceeding the vertical relative motion between said platforms.

Claim 13

A method for controlling the rate of closure or separation and the landing site of a carrier for cargo or personnel during transfer from a landing platform onto a lifting platform while said platforms are subject one with respect to the other to vertical and/or lateral movement due to waves and/or wind within an envelope of motion, said method including the steps of: paying out the cable of a lifting winch on said lifting platform to an elevation for access thereto from said landing platform while said platforms move one with respect to the other pursuant to said envelope of motion, said lifting winch having means to preestablish a first constant tension level in the cable thereof, coupling the cable of a downhaul winch on said landing platform to the cable of the lifting winch, said downhaul winch having means to select one of preestablished second and third constant tension levels in the cable thereof, said second constant tension level being less than said first constant tension level and said third constant tension level being greater than said first constant tension level, imposing the said third constant tension level on the coupled cables by energizing the downhaul winch to maintain the carrier on the landing platform, eliminating slack in the coupled cables by energizing the lifting winch while the carrier and lifting platforms approach each other pursuant to said envelope of motion, energizing said lifting winch to impose the preestablished first constant tension level in the coupled cables to maintain the carrier on the landing platform through continued relative motion pursuant to said envelope of motion, said lifting winch at the preestablished first constant tension level having a wind-up velocity above a prescribed minimum take-up velocity precluding cable slack while said platforms move one with respect to the other, energizing said downhaul winch to impose said preestablished second constant tension level which is less than said first constant tension level and at a controllable wind-up speed on the coupled cables to move the carrier from the landing platform when the carrier recedes away from the lifting platform, and maintaining the cable take-up velocity by the lifting winch at a value exceeding the vertical relative motion between said platforms.