Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
  • B66D1/00—Rope, cable, or chain winding mechanisms; Capstans
  • B66D1/60—Rope, cable, or chain winding mechanisms; Capstans adapted for special purposes
  • B66D1/74—Capstans
  • B66D1/7405—Capstans having two or more drums providing tractive force

Definitions

• THIS INVENTION relates to improvements in or relating to winches.
• Winches have been proposed, and are described and illustrated in U.S. Patent Specification Nos. 4,274,606 and 4 ⁇ 230,306, in which a tailing means is provided at the tail end of a rotatable drum.
• the tailing means is intended to receive only a single turn of rope or cable and comprises a circumferential groove and/or a high friction material.
• An increase in tension in the turn of rope received by the tailing means has the effect of increasing the force with which the same is gripped by the tailing means.
• the tailing means holds the tail end of rope in position so that, on the one hand, an increase in the tension applied to the load end of the rope will not cause the turns of rope to slip around the drum and, on the other hand, the tail end of the rope will not become slack and, possibly, foul the line.
• U.S. Patent Specification. No. 4,272,606 stresses that the area of increased friction must only be provided at the tail end of the drum, because a number of turns of rope adjacent the tail end might otherwise become slack. Thus, in these previously proposed winches, the rope or cable and the cable bearing surface are subjected to uneven frictional wear.
• U.K. Patent Specification No. 1,599,521 describes a dual axis quadruple capstan winch in which cable tension is overcome by providing a large number of grooves so that a large number of turns of cable are borne by the winch.
• the driving capstans of the winch are disposed on more than one axis, it is difficult correctly to balance the torque applied by the load about the two axes.
• This invention provides ⁇ winch comprising ⁇ rot ⁇ t ⁇ ble bearing surface for a cable, wherein the friction between the surface and a given cable material at a given cable tension varies continuously, or sfepwise in a plurality of steps, along a rotational axis.
• the winch includes a capstan having a surface the coefficient of friction of which increases along the rotation axis of the capstan. Additionally, or alternatively, the winch comprises a capstan provided with a plurality of circumferential grooves, the cable bearing surface area of each groove being different.
• the friction acting between the cable and the capstan can be kept at substantially the same level by increasing the coefficient of friction and/or by decreasing the effective contact area (and thus increasing the pressure) between the cable and the capstan.
• the circumferential grooves are worn at substantially the same rate, facilitating maintenance.
• the present invention enables the provision of a winch fn which cable tension is overcome in relatively few turns of cable, so that a single axis twin capstan winch, which has not been previously proposed, becomes feasible.
• the present invention also provides a capstan winch in which the driving capstans of the winch are disposed on a single axis and comprise first and second capstans.
• the first and second capstans are drivable in contrarotat ⁇ on, for example by means of an epicyclic gear train, and a brake ⁇ s provided for securing the first and second capstans against rotation with respect to each other, so that they act as a single fixed capstan.
• the first and second capstans can continue to support a load even whilst parts of the driving mechanism are removed for inspection or repair.
• Figure 1 is a schematic side elevational view of a single-axis twin capstan winch in accordance with the invention
• Figure 2 illustrates the path followed by a cable guided by the twin capstan winch of Figure 1 .
• Figure 3 is a cross-sectional view taken along the line III- III of Figure 1.
• Figure 1 shows a twin capstan winch comprising a first, single groove, capstan 1 and a second capstan 2, sharing a common rotation axis, and a plurality of sheaves or grooved pulleys 3.
• three sheaves 3 are rotatably mounted on a shaft 4 which is parallel to the common rotation axis of the first and second capstans 1, 2.
• a fourth sheave 3 is rotatably mounted on a shaft 5 which is slightly offset from that axis to facilitate passing cable over the fourth sheave 3 and the single groove capstan 1.
• the capstans 1, 2 are adapted to be driven in rotation by means of a motor 6, a sun gear 7 fixed to a drive shaft of the motor 6, a planet gear 8 rotatably mounted on an integral shaft 9 of the second capstan 2 and an internal gear 10 of the first capstan 1.
• a brake (not shown) is also provided for preventing relative rotation of the capstans 1, 2 if desired.
• the second capstan 2 is provided with three circumferential grooves 1 1 which are offset along the capstan rotation axis relative to the grooves of the three sheaves 3 on the parallel shaft 4 by half a groove's width.
• the circumferential grooves 1 1 comprise a high friction material and the coefficient of friction increases from the high tension (load) end to the low tension (tail) end of the second capstan 2.
• Preferred high friction materials include Silumin, which is a high silicon content aluminium such as AL20 with more than 12% silicon content, and, for use in potentially corrosive environments, high friction polymers such as polyurethanes, polypropylenes and Ka ⁇ tex, which is a polyvinylchloride based material. "Silumin” and “Kautex” are Trade Names.
• each groove comprises alternating areas of Kautex and Silumin, the former providing the high friction component and the latter serving to support the cable.
• the coefficient of friction of at least some of the surface of the second capstan 2 for a steel cable should preferably be significantly greater than that of steel on steel.
• the density decreases exponentially from the high tension (load) end to the low tension (tail) end of the second capstan 2.
• the widths of the grooves may also be varied (not shown) so as to vary the pressure between the cable and the surface of each groove at a given cable tension.

Landscapes

• Mechanical Engineering (AREA)
• Engineering & Computer Science (AREA)
• Pulleys (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Ropes Or Cables (AREA)
• Tension Adjustment In Filamentary Materials (AREA)
• Air Bags (AREA)
• Superheterodyne Receivers (AREA)
• Earth Drilling (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Soil Working Implements (AREA)
• Transmission Devices (AREA)
• Lift-Guide Devices, And Elevator Ropes And Cables (AREA)
• Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
• Jib Cranes (AREA)
• Friction Gearing (AREA)
• Chain Conveyers (AREA)
• Handcart (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Braking Arrangements (AREA)
• Bridges Or Land Bridges (AREA)
• Processes Specially Adapted For Manufacturing Cables (AREA)
• Insulated Conductors (AREA)
• Manufacture Of Motors, Generators (AREA)
• Moulding By Coating Moulds (AREA)
• Storage Of Web-Like Or Filamentary Materials (AREA)
• Window Of Vehicle (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10541768

Family Applications (1)

Country Status (19)

Cited By (1)

Families Citing this family (3)

Citations (11)

• 1983
  • 1983-04-27 GB GB838311454A patent/GB8311454D0/en active Pending
• 1984
  • 1984-04-27 ZA ZA843155A patent/ZA843155B/xx unknown
  • 1984-04-27 DE DE8484901789T patent/DE3469433D1/de not_active Expired
  • 1984-04-27 GB GB08410905A patent/GB2138768B/en not_active Expired
  • 1984-04-27 WO PCT/GB1984/000144 patent/WO1984004291A1/en active IP Right Grant
  • 1984-04-27 CA CA000453196A patent/CA1246540A/en not_active Expired
  • 1984-04-27 IL IL71687A patent/IL71687A/xx not_active IP Right Cessation
  • 1984-04-27 AT AT84901789T patent/ATE32598T1/de not_active IP Right Cessation
  • 1984-04-27 DD DD84262412A patent/DD218340A5/de not_active IP Right Cessation
  • 1984-04-27 IT IT20732/84A patent/IT1174524B/it active
  • 1984-04-27 EP EP84901789A patent/EP0150187B1/en not_active Expired
  • 1984-04-27 HU HU842419A patent/HU195162B/hu not_active IP Right Cessation
  • 1984-04-27 JP JP59501794A patent/JPS60501156A/ja active Pending
  • 1984-04-27 BR BR8406815A patent/BR8406815A/pt unknown
  • 1984-04-27 AU AU28670/84A patent/AU588217B2/en not_active Ceased
  • 1984-04-30 IN IN314/MAS/84A patent/IN160709B/en unknown
  • 1984-12-07 NO NO844918A patent/NO844918L/no unknown
  • 1984-12-20 FI FI845058A patent/FI78053C/fi not_active IP Right Cessation
  • 1984-12-21 DK DK627384A patent/DK153021B/da not_active Application Discontinuation
  • 1984-12-25 RO RO116900A patent/RO94168B/ro unknown

Patent Citations (11)

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