GB1558938A - Arrangement for controlled winding of a cable on winch drums - Google Patents

Description

(54) AN ARRANGEMENT FOR CONTROLLED WINDING OF A CABLE ON WINCH DRUMS (71) We, AUKRA BRUK A/S, a Norwegian Body Corporate of 6420 Aukra, Norway, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an arrangement for controlled winding of a cable on a winch drum.

For satisfactory winding a cable on a drum it is required that the cable can be wound in sequential uniform layers. Then, the drum can accommodate a maximum length of cable and the cable is subject to a minimum of damage when stressed. It is often difficult to wind a cable uniformly on a drum, even when said cable is clean and unmarked and has no joints. The system for controlling a cable on a drum most utilized to day comprises rolls supported on a carriage or a cradle which is slidable on tracks or shafts extending parallel with said drum. Such a system has been described e.g. in the Norwegian Patent Application No. 1647/72.

In the known systems the rolls are provided adjacent to each other at a mutual distance and normal to the drum axis. Said mutual distance approximately corresponds to the cable diameter. The carriage or cradle is reciprocated by the aid of a screw the pitch and rotation of which is adapted to the cable diameter. Instead of a screw a hydraulic cylinder has also been utilized, which discharges hydraulic liquid in relation to the cable diameter and the drum revolutions per minute by the aid of a control valve. A disadvantage of the mentioned systems is that they lack flexibility, i.e. they must be adapted to the cable diameter.

Other disadvantages are that when the rolls and other mechanical aids for advancing a carriage or a cradle are worn. this will influence the winding quality.

Another known system is the Lebus (Registered Trade Mark) system. According to that system grooves are drilled in the drum adapted to every separate cable diameter, so that said cable can wind itself onto the drum, but the angle of incidence of the cable must then be less than + 1.25 normal to said winch drum. It is disadvantageous that the winch must be provided far from any blocks.

If the angle of incidence is more than 1.25", the cable will either climb onto the previous layer or be positioned at too large distance from the next turn on the drum. This results in uncontrolled winding.

Said disadvantages are eliminated by the present invention. The basis of the invention is the ability of the cable to wind itself onto a drum, when the angle of incidence towards the winding dirction is between 0 and 1.25 .

A control means keeps the cable within said limits regardless of the cable diameter. The arrangement according to the present invention is characterized by the features stated in the following claims and by the following description with reference to the drawing.

Figure 1 discloses a diagrammatic embodiment of the apparatus according to the invention.

Figure 2 illustrates various phases of cable position during winding operations.

Figure 3 illustrates a preferred embodiment of the scanning means of the arrangement according to the invention.

Figure 4 illustrates a winch and a winding arrangement according to figure 1 having an alternative mode of operation.

According to figure 1 a cable is wound on the drum 3. A winding carriage 4 supports two rolls 6 and 7. The function of said rolls is to guide the cable to its correct position during winding operations. Reference number 8 indicates shafts or tracks on which the carriage can move. Reference number 5 indicates a hydraulic cylinder, which pulls said carriage reciprocating along the drum parallel with the drum center line. Reference number 9 indicates an electro hydraulic servo valve and 10 indicates a direct connected motor-driven pump. Reference numbers 1 and 1', 2, and 2' indicate inductive or capacitive scanners which scan the cable dis tance. Scanners 1. t',and2,2' are connected in a summation box 11 and 12 respectively.

Signals from 11 and 12 are transmitted to a differential amplifier 13 and then to said servo valve 9. which controls the hydraulic fluid to cylinder 5.

The scanners l and 2 are here arranged parallel with the drum center line and at a mutual distance which is larder than the dis tance between rolls 6 and 7. The scanners 2' and l' are provided in the same manner, so that all four scanners form a rectangle. Said scanners are connected in such a way that scanners 1 and 1' cooperate and scanners 2 and 2' cooperate resp., and each pair is positioned diagonally to said other pair. In figure 2 a cable is arranged arbitrarily between scanners 1 - 2 and 2'- 1'. normal to a line extending parallel with the winding drum.The distance between scanner 1 and said cable is indicated by A. the distance between scanner 2 and said cable is indicated by B. the distance between scanner 2' and said cable is indicated by C, and the distance between 1' and said cable is indicated by D.

The following equation, thus. holds good: A + D = B + C. If said cable is displaced parallel with its original position. the equation A + D = B + C still holds good. If however, said cable is moved a small angle a towards scanner 2. distance B is reduced bv a small length A and distance A is increased by a length A. Distances C and D are temporarily constant. We then find. that the difference (A + D) - (B + C) = 2A,i.e. a doubling duc to the fact that scanners l and 1' cooperate and scanners 2 and 2' cooperate. The signal received due to this angular deflection is utilized for activating the winding carriage 4 in one direction or the other. A parallel translation of the cable, however, will not influence the result.Due to these advantages, the guid ing rolls 6 and 7 can be positioned at a large mutual distance relative to the cable, so that shackles. joints or the like can pass freely.

The winding operation is as follows: When a cable is hcaved in onto the drum it will be positioned close to the previous turn if the incoming cable is held at a small angle towards the winding direction on the drum. If said angle is too large the cable will climb onto the preceding layer and if the cable extends at an angle away from the winding direction it will be positioned on the drum with too much space between turns. It is assumed that the cable direction from the winch is such that said cable is in contact with the guide roll 7 in figure 1. When the drum heaves in cable said cable will gradually move as indicated by the arrow 14 and there will be an angle a1 l between a line normal to the drum center line and the cable.Said angle will cause a difference between signals 1,1'.

and 2,2', as mentioned above. The output from the differential amplifier is then a signal that activates the servo valve 9, which feeds oil to cylinder 5, which is turn moves the carriage 4 until said angle cr a is nullified or as small as desired. The carriage then stops. If the incoming cable were to change its point of engagement with the drum, so that the cable changes over from guide roll 7 to guide roll 6. figure 1. there would be an angle a opposite to the winding direction. This would cause a difference of the pairs of scanners 1,1', and 2,2' reverse to that mentioned above.This, again, results in activation of the servo valve 9. which displaces the carriage 4 in the direction of the arrow 15 until said angle a is nullified, which means that the cable is still under control.

Said scanners or signal transmitters 1.1'.

and 2,2' are preferably inductive and designed as E shaped transformers. see figure 3.

In an alternative mode of operation of said inductive scanners, see figure 4. an impulse is received from the winch drum after each complete, half or quarter turn. Said impulse is transmitted by the signal generator 20 across the switch 2 1. which is then switched and transmits the control signal to an electro hydraulic valve 9, which starts the winding carriage. Said signal is transmitted across box 22, which determines the direction of the winding carriage.When the cable has an angle a with or towards the winding direction 14, the signal transmitters 1.1' and 2.2' will. as mentioned above, transmit a signal to switch 2 1 and break the signal to said hydraulic valve 9 and stop the winding carriage A. Switches 23 and 24 are activated alternately at the end point of said carriage and activate said box 22, so that the electro hydraulic valve 9 is switched and said carriage is.

thus. reversed. If the winch drum stops and changes its direction of rotation, signal generator 25 with signal box 26 switches box 22, so that the winding direction is reversed again. The advantages of this arrangement are that the winding carriage is positively controlled to complete winding the length of the drum ill both directions, regardless of obstacles on the drum. In the known systems the hazard exists that the winding carriage will abruptly change its winding direction if the cable contacts an obstacle on the drum.

c.g. a shackle. Furthermore, the possibility of arranging the guide rolls 6 and 7 at a large mutual distance is maintained. so that shackles and the like can pass between them. Mod ifications within the scope of the invention as defined in the claims are feasible. For instance, only two inductive gencrators can be utilized, one at each side of the cable to measure the distance between said cable and the generator. In that case the guide rolls should have a mutual distance approximately like the cable diameter.

WHAT WE CLAIM IS: 1. An arrangement for controlled winding of a cable on winch drums, characterized in that a carriage movable parallel with the axis of rotation of said winch drum is provided with at least a pair of scanners (1,1',2,2') of the capacitive of inductive kind, which are provided to scan the direction of said cable relative to a line normal to the axis of rotation of the drum, as well as two cable guide rolls (6,7) one on each side of said cable and provided to prevent said cable from mechanical contact with said scanners.

2. An arrangement as stated in claim 1, characterized in that two pairs of scanners (1,1',2,2') are utilized.

3. An arrangement as stated in claims 1 and 2, characterized in that said scanners are E-shaped transformers.

4. An arrangement as stated in claims 1-3, characterized in that the member of the or each pair of scanners are positioned on respective sides of the cable.

5. An arrangement as stated in claims 1-4, characterized in that the signals from one pair of scanners (1,1') is summed up and that the signals from the other pair of scanners (2.2') is summed up, the two scanners of each pair being positioned diagonally relative to each other.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. measure the distance between said cable and the generator. In that case the guide rolls should have a mutual distance approximately like the cable diameter. WHAT WE CLAIM IS:

1. An arrangement for controlled winding of a cable on winch drums, characterized in that a carriage movable parallel with the axis of rotation of said winch drum is provided with at least a pair of scanners (1,1',2,2') of the capacitive of inductive kind, which are provided to scan the direction of said cable relative to a line normal to the axis of rotation of the drum, as well as two cable guide rolls (6,7) one on each side of said cable and provided to prevent said cable from mechanical contact with said scanners.

2. An arrangement as stated in claim 1, characterized in that two pairs of scanners (1,1',2,2') are utilized.

3. An arrangement as stated in claims 1 and 2, characterized in that said scanners are E-shaped transformers.

4. An arrangement as stated in claims 1-3, characterized in that the member of the or each pair of scanners are positioned on respective sides of the cable.

5. An arrangement as stated in claims 1-4, characterized in that the signals from one pair of scanners (1,1') is summed up and that the signals from the other pair of scanners (2.2') is summed up, the two scanners of each pair being positioned diagonally relative to each other.