US2908481A

US2908481A - Winding and paying out apparatus

Info

Publication number: US2908481A
Application number: US649189A
Authority: US
Inventors: Howard William Lewis
Original assignee: WELIN MACLACHLAN DAVITS Ltd
Current assignee: WELIN MACLACHLAN DAVITS Ltd; WELIN-MACLACHLAN DAVITS Ltd
Priority date: 1957-03-28
Filing date: 1957-03-28
Publication date: 1959-10-13
Anticipated expiration: 1976-10-13

Description

Oct. 13,1959

W. L- HQWARD WINDING .AND PAYING OUT APPARATUS Filed March 28, 1957 3 Sheets-Sheet l I A. b

L00 0 ZZ'duJ-uw Oct. 13, 1959 w. L. HOWARD WINDING AND PAYING OUT APPARATUS 3 Sheets-Sheet 2 Fil ed March 28, 1957 NQE EM w

Oct. 13, 1959 Filed March 28, 1957 W. L. HOWARD WINDING AND PAYING OUT APPARATUS 5 Sheets-Sheet 3 Imam:

w g A a-(0M4 E 421 United States Patent C "cc WINDING AND PAYING OUT APPARATUS William Lewis Howard, London, England, assignor t Welin-Maclachlan'Davits, Limited, London, England, a company'of Great Britain Application March 28, 1957, Serial No. 649,189

4 Claims. (Cl. 254- 185) This invention relates to double coupled Winches, that is to say a winch, having at least two rope drums driven by one motor, adapted for the hoisting or lowering of two or more independent loads, for example lifeboats.

In a known type of motor driven double coupled winch the arrangement is such that it is impossible for both loads to be hoisted simultaneously, but both loads may be simultaneously lowered, and also, during the lowering of one of the loads, the other may be hoisted. This is accomplished by a winch comprising two rope drums and a reversible motor having a driving gear, each drum being associated, through its own individual transmission gear, with one element ofa manually operable clutch, the other element of Which is operatively connected to a single revolvable member, adapted for rotation in hoisting direction, but prevented from rotating in lowering direction, said member being connected through its own freewheel device operative, in hoisting direction, with a gear Wheel, which is in permanent operative association with said driving gear, it being understood that the two freewheel devices are operative in opposite directions.

An object of the present invention is to provide a motor driven double coupled winch of the above type, in which, when the motor is caused to rotate in one direction, one drum of said Winch is automatically positively driven, the other being free to rotate and in which, when the motor is caused to rotate in the other direction, the other drum is automatically positively driven while the first-mentioned drum is free to rotate.

According to the present invention, a double coupled winch comprises a reversible motor and two rope drums, or sets of rope drums, each drum, or set of drums, being coupled through suitable transmission gears with one element of a freewheel device, for example a pawl and ratchet mechanism, the other element of which is coupled to a driven member of a centrifugal clutch, the driving member of which is coupled to the drive shaft of the reversible motor, the arrangement, in particular that of the freewheel device, being such that, when the reversible motor is caused to rotate in one direction, only one of the rope drums, or set of drums is positively driven, the other being free to rotate.

Preferably a manually operated brake is provided for each rope drum, or set of drums, intermediate the respective freewheel device and said drum.

Preferably the drive shaft of the motor extends outwardly from both ends of the motor casing, each end of the drive shaft being then coupled to the driving member of the centrifugal clutch. As an alternative, the electric motor may have a drive shaft extending from one end of the casing only, and in this arrangement the drive shaft is coupled through an arrangement of bevel gears with the driving members oftwo independent centrifugal clutches.

The present invention is now described, by way of example, with reference to the accompanying drawings in which 2,908,481 Patented Oct. 13, 1959 Figure 1 is a front elevation of a double coupled winch;

Figure 2 is a plan view of the winch;

Figure 3 is an enlarged scale vertical section of a transmission mechanism shown in elevation at the right end of Figure 1.

Referring to the accompanying drawings, a double coupled Winch comprises a frame 1 on whichis mounted an electric motor 2 having drive shafts 3a and 3b extending outwardly from both ends of a casing 4 of said motor. The righthand shaft 3a, shown in Figure l, is connected to a transmission mechanism to be described hereinafter with reference to Figure 3, and the lefthand shaft 3b is connected to a transmission mechanism 101, similar to the mechanism 100.

Referring to Figure 3, the drive shaft 3a is rotatably mounted in a clutch housing 5 and is coupled to a centrifugal clutch 6. This centrifugal clutch 6 comprises driving members 7 biased into retracted position by means of tension springs 8. The driving members 7 are mounted on the end of the drive shaft 3a so as to be movable in a radial direction, whereby upon rotation of said shaft 3a the driving members 7 are flung outwardly by centrifugal force and make frictional contact with a clutch drum 9. The drum 9 is carried by a housing 10 of a one-way-drive freewheel device 11 which housing 10 is rotatably carired by a spindle 12. The free Wheel device 11 comprises pawls 13 pivotally coupled to the housing 10 and adapted, when said housing is rotated by the shaft 3a through the agency of the centrifugal clutch 6, to engage with a ratchet 14 fast on the spindle 12. A

pinion 15 is secured on the spindle 12 and engages with a gear wheel 16 carried by a shaft 17 rotatably mounted in a gear box casing 18. A pinion 19 is secured on the shaft 17 and meshes with a gear wheel 20 carried by a shaft 21 also rotatably mounted in the casing 18, which shaft 21 carries a pinion 22 which in turn meshes with a gear Wheel 23 integral a rope drum 24.

A centrifugal brake .25-is mounted on the shaft 17, which brake comprises shoe members 26 adapted to make frictional engagement with a brake drum 27 fast with the casing 18, which shoe members are biased into retracted position by tension springs 32. A manual brake 28 is provided, which is of the band type, and is adapted to bear against a cylindrical brake member 29 mounted, for rotation in one direction, around the shaft 17. This cylindrical brake member 29 pivotally carries pawls 30 adapted to engage with a ratchet 31 fast on the shaft 17 when said shaft is rotated in a predetermined direction and thereby rotate said brake member 29.

With the arrangement shown'in Figure 3, a positive drive from the electric motor 2 passes down the shaft 15, gear Wheel- 16, pinion 19, gear wheel 20, pinion 22 and gear wheel 23, and so rotates the rope drum 24 in an anticlockwise direction to wind in rope on to the drum 24. The drive from the shaft 3a into the shaft 17 is not transmitted to the cylindrical member 29 because of the arrangement of the pawl 30 and ratchet 31, nor

is 'said drive passed through the centrifugal brake 25 becausethe strength of the tension springs 32 is such that the shoe members 26 are retained in retracted position, the centrifugal force caused by rotation of the shaft 17 by the motor 2 being insufiicient to overcome the strength of said springs.

When the motor is stationary, or rotating in an anticlockwise direction rope may be unwound from the drum 24 merely by releasing the manual brake 28 and applying tension to said rope. In this particular instance a drive passes from the drum 24 back through the various pinions and gear wheels to the shaft 12 which is thereby rotated in an anticlockwise direction. The pawls 13 and ratchet 14 will cause the housing and drum 9 to rotate in an anticlockwise direction, but, if the motor 2 is stationary then the driving members 7 are in re tracted position out of contact with the drum 9, so no drive will be transmitted to the shaft 3a and motor 2. Alternatively, if the motor is rotating in an anticlockwise direction so that there is engagement between the driving members 7 and drum 9, slip will occur at the free wheel device 11, provided the speed of rotation of the shaft 12 is not greater than the speed of rotation of the shaft 3a. The rate at which rope is unwound from the drum 24 is controlled by means of the brake 28 or, if this is fully released, by means of the centrifugal brake 25, the arrangement of which latter brake is such that when the rate at which the rope is unwound from the drum 24 reaches a predetermined limit the shoe members 26 make frictional contact with the brake drum 27.

When the motor 2 is rotated in a clockwise direction to Wind in rope on to the drum 24, the shaft 17 rotates in an anticlockwise direction and rotates in a clockwise direction when rope is unwound from the drum 24. The pawl 30 is arranged to permit the ratchet 30 to: turn freely when the shaft 17 rotates in an anticlockwise direction, but to engage operatively with said ratchet when the shaft 17 rotates in a clockwise direction. It will thus be appreciated that the manual brake 28 is operative only to prevent rotation of the shaft 17 in a clockwise direction and so, by adjusting the pressure at which said brake bears against the cylindrical member 29 the speed of rotation of said shaft 17 and the drum 24 in a clockwise direction can be controlled.

From the foregoing description it will be realized that the transmission mechanism 100 transmits a drive to the rope drum 24 only when the motor 2 rotates in a clockwise direction. The transmission mechanism 101 is similar to the mechanism 100 except that it includes a oneway-drive freewheel device similar to the freewheel device 11 but arranged to operate in the reverse direction, that is to say it transmits a drive to its rope drums 34 only when the motor 2 rotates in an anticlockwise direction. Therefore, whilst rope is being wound onto the drum 24, rope may be paid off from the drum 34 or vice versa.

Assuming the double coupled winch as hereinbefore described be connected to two ships lifeboats suspended from davits, the sequence of operation of said winch is as follows:

To lower the lifeboats, it is necessary only to release the manual brakes 28 and the boats will be lowered by their own weight, both rope

drums

24 and 34 being free to rotate because there is no positive coupling between them and the electric motor 2 because of the centrifugal clutches 6. Should it be desired to stop the lowering of either of the boats, then the respective manual brake is fully applied. The maximum speed at which the boats may be lowered is controlled by the centrifugal brakes 25. If it is desired to hoist up one of the boats 1t is necessary only to switch on the reversible electric motor 2 so that it rotates in the desired direction, that 1s to say clockwise for the rope drum 24 or anticlockw se for the rope drum 34 and a drive from said motor will pass through the shafts 3a and 3b and wi centrifugal clutches attached thereto, but only through one freewheel device and hencethrough only one transmission mechanism or 101. Therefore, whilst one boat is being hoisted it is possible to lower the other boat. Due to the arrangement of the centrifugal clutches and freewheel devices it is impossible to couple both sets of

drums

24 and 34 to the electric motor 2 at any one time and therefore there is no danger of overloading said motor.

It will thus be seen that according to the present invention there is provided a motor driven, double coupled winch in which, when the motor is caused to rotate in one direction only one drum or set of drums is positively driven, the other drum or set of drums being free to rotate and in which, when the motor is caused to rotate in the other direction the other drum or set of drums is automatically positively driven whilst the first mentioned drum or set of drums is free to rotate,

What is claimed is:

l. A double coupled winch comprising a reversible motor, two rope drums, a first centrifugal clutch having a driving member and a driven member, means coupling said driving member to said reversible motor, a first one-way-drive freewheel device having a driving element and a driven element, means coupling the driven member of said first centrifugal clutch to the driving element of said first freewheel device, said first freewheel device being operative for transmitting drive from said first centrifugal clutch to the driven element of said first freewheel device only when said motor is rotated in one direction, means coupling the driven element of said first freewheel device to one of said rope drums, a second centrifugal clutch having a driving member and a driven member, means coupling the driving member of said second centrifugal clutch to said reversible motor, a. second one-way-drive freewheel device having a driving element and a driven element, means coupling the driven member of said second centrifugal clutch to the driving element of said second freewheel device, said second freewheel device being operative for transmitting drive from said second centrifugal clutch to the driven element of said second freewheel device only when said motor is rotated in the opposite direction, and means coupling the driven element of said second freewheel device to the other of said rope drums.

2. A double coupled winch according to claim 1 wherein both the first and second freewheel devices each comprise a pawl and ratchet mechanism, the pawl constituting the driving element and the ratchet constituting the driven element.

3. A double coupled winch according to claim 2 wherein the motor includes a casing and a drive shaft, the motor drive shaft extending outwardly from both ends of said casing, each end of the drive shaft being coupled to the driving member of its respective centrifugal clutch.

4. A double coupled winch according to claim 3 wherein a manually operated brake is provided for each rope drum intermediate the respective freewheel device and said drum.

References Cited in the file of this patent UNITED STATES PATENTS 1,983,250 Tibbetts Dec. 4, 1934 2,010,280 Thiman Aug. 6, 1935 2,224,503 Kahlerth Dec. 10, 1940 2,271,429 Harry Ian. 27, 1942 FOREIGN PATENTS 22,127 Great Britain 1906 "I Loni