WO1984003876A1

WO1984003876A1 - Guiding on device for winchdrum

Info

Publication number: WO1984003876A1
Application number: PCT/NL1983/000013
Authority: WO
Inventors: Jan Fonger Minnee
Original assignee: Jan Fonger Minnee
Priority date: 1982-02-11
Filing date: 1983-04-07
Publication date: 1984-10-11
Also published as: NL8200512A; EP0171386A1; EP0171386B1

Abstract

The invention, belonging to the category of automatic wire spoolers, aims at a simplier application of the known principle that a taut wire chooses the shortest distance between two points, but if this does not exist, there will be no preference for a particular position except for following the winding on the drum. This can be realised by a travelling sheave, moving along an arc-formed track in a perpendicular plane between drum and fixed sheave. The radius of this arc depends on the relative distance of the spooler sheave from drum and fixed sheave, the drumwidth and the height of the top of the track above the baseline, formed by the tangent line on drum and fixed sheave. The sheave may be fitted on a swinging arm, but for reduction of dimensions and better adaption to theoretical and practical phenomena, the sheave frame should rotate and roll simultaneously. The spooler can be counterbalanced so that when the wire slackens, it remains in its original position. Such a construction allows a very compact spooling for a winch.

Description

GUIDING ON DEVICE FOR WINCHDRUM

The invention concerns an appliance which becomes necessary to wind a wire evenly over the full length of the drum in cases where the fleet angle exceeds approx.4^o or where the distance of the lead or fixed sheave in front of the drum is shorter then approx.7 times the drumlength.

Conventional spooling arrangements adjust the wire position opposite the drum by means of mechanical drives, the invention however belongs to the category working on the principle that the appliance is directed by the previously laid-on drumwinding alone and all other influences are eliminated.

This condition is fulfilled if, in any position of the spooling gear between drum (3) and fixed lead (2) , the total length of wire between the meeting points on drum and sheave remains constant fig.2 - a + c = a' + c'. As the taut wire always tries to find the shortest distance between those two points and if this does not exist, there will be no preference for any position at all. The spooler must therefore,apart from moving along the drum also travel along a path such that a + c remains constant. This path lies in a plane perpendicular to the wire and proves to be almost circular with a radius R depending on the distances a, b, c, the angle of the wire at the spooler sheave.

Because the force generated by the wire in the spooler should not influence the movement either, it is necessary that the direction of this force must be perpendicular to the path and should not cause interfering resistances along the path.

A wellknown device fulfilling these conditions produces the required path by means of a sheave rotating and translating along a shaft which in turn, by means of cranks placed at either end at different angles, makes an oscilating movement in front of the drum, the character of the path being governed by the length and angle of the cranks. The use of swiveling bearings for this shaft restricts the cranklength in comparison with the drum length and so the application to the condition a > 2.4 b.

For these long drums and high loads special high tensile materials are required . in addition, complicated dismounting and provisions for maintaining the proper position of the sheave when the wire slackens are necessary. The invention aims at a device with applications up to a = b, merely depending on the wire run over the leadsheave (2) with the intention to realise more compact winch arrangements by simpler means; minimum a + c. The required path is produced by a "tumbler" sheave, pivoting on a foundation in front of the drum such that the tangent to drum and fixed lead halves the tumblers height, causing the wire reaction to point at the hinge.

This condition determines various related factors e.g. each ratio a/c determines one optimum curve/radius and minimum size of the spooler related to b.

It also indicates that the number of layers on the drum has limits, if the tangent cuts the tumbler above midheight, then a preference for the central part of the drum will be shown (empty drum) whereas guiding on to a full drum a preference for the sides will be shown. Due to the steering forces developed by the wire already on the drum, the working range between unacceptable preferences is sufficient for practical use and can be increased by choosing a larger tumbler than the minimum size. Besides : the tendency to cover the sides of a full drum may be useful in cases where a mechanically driven tumbler spooler may be advantageous in comparison with the usual transverse guiding-on gear with diamond threaded drive shaft, where the required force is much heavier (fig.5) and the means weaker.

A practical way of producing the required path is found in a tumbler not having a fixed hinge pin, but a round toe which while rocking is also rolling over a transverse rail, thus reducing the physical dimensions of the tumbler, reducing support pressure by spreading it over a larger surface and enabling the device to be counterbalanced so that, when the wire slackens, it remains in its original position (fig.3) Structurally the generated forces in the tumbler do not require the use of special material or parts.

A centering system to ensure the tumbler is kept central in front of the drum using cross wire ropes and a wide enough toe to ensure lateral stability is simple but sufficient. A further measure to minimize sheave wear is given by an additional hinge point in the centreline of the winch, at a certain distance from the device causing the toe to swing gradually over the rail in order to swivel the sheave in the correct angle of the wire run from drum to fixed lead. This may be realised by means of a protruding cam near the bottom of the toe reaching into a fixed camplate, in which it moves vertically up and down when the tumbler rocks and rolls. When such a camplate is also mounted at the other side of the tumbler with a different shaped profile to follow the cam along its path, then the tumbler will be secured in all directions and can be used in all positions if required.

Fig.4 presents a compact winch arrangement, providedwith slotted plates and cam (2) , while fig.5 shows a tumbler spooler with mechanical external drive.

Claims

1. A tumbler-sheave spooling device for winchdrums fitted between drum and fixed lead with the feature that the sheave travels along a certain circular path by rotating around a fixed centre such that the movement is caused exclusively by the wire position on the drum with external steering as an option.

2. A tumbler-sheave spooling device as mentioned under 1 with the feature that the required path is produced by rotating and rolling.