GB2327659A

GB2327659A - Mounting means for supporting cables of a lifting gear

Info

Publication number: GB2327659A
Application number: GB9816125A
Authority: GB
Inventors: Udo Gersemsky; Alfred Fanger
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1997-07-23
Filing date: 1998-07-23
Publication date: 1999-02-03
Anticipated expiration: 2018-07-23
Also published as: ATA68198A; GB2327659B; DE19732539C2; IT1301819B1; ITMI981472A1; GB9816125D0; DE19732539A1

Abstract

A mounting means for the spread ends of a number of pairs of supporting cables 1 of a load member 3, e.g. a cross bar, which are attached at one end to at least one winding drum 6, consists of guide elements 5 and guide rails 4 which are inclined towards one another. The cables in each pair are guided directly, or indirectly via rollers, between the drum and load member at a spreading angle α to one another. The mounting means automatically adjusts α upon load member elevation and ensures that a maximum set value is not exceeded. Preferably the guide elements have a limited range of movement defined by the extent of the guide rails and the angle of inclination of the guide rails relative to one another is such that the supporting cable is perpendicular to the guide element longitudinal axis. Preferably the cable drum has a right-hand winding groove (11, Figure 3) and a left-hand winding groove (12, Figure 3), and each pair of supporting cables is formed by one cable of each winding sense, and also the mounting means is located adjacent to the winding drum (4, Figure 3), the cables being fed to the mounting means via deflecting rollers (13a and 13b, Figure 3) attached to the load member. Alternatively each pair of supporting cables is guided to the load member via a roller 10 mounted horizontally level with the drum where the cables of each pair diverge after the roller at an angle α.

Description

2327659 A MOUNTING MEANS FOR SUPPORTING CABLES OF A LIFTING GEAR The

invention relates to a mounting means for the supporting cables of a lifting gear, in particular for the lifting gear of overhead cranes and trolleys.

A trolley with a built-in lifting gear is known from German Patent Application No. 34 40 0131 Al. The lifting gear includes two cable drums each having a pair of supporting cables. The cables of each pair are guided towards the load suspension means at an angle to one another, known as the "spreading angle". At the load suspension means, the supporting cables are turned back towards the cable drum via deflecting rolls. Travelling mechanisms act on the spread ends of the supporting cables, the travelling mechanisms being movable on a travelling rail provided beneath the cable drum, dependent on the load height. In this arrangement the travelling mechanisms are moved such that the spreading angle does not exceed a given value.

The disadvantage of this arrangement is that a control means is necessary in order to move the travelling mechanisms in height-dependent manner as desired, e.g. using the detected spreading angle or the detected load height.

It is an object of the invention to provide a mounting means for supporting cables of a lifting gear in which the spreading angle is automatically adjustable at least within a given range and a maximum set spreading angle is not exceeded.

According to the invention there is provided a mounting means for the supporting cables of a lifting gear having at least one cable drum, at least a pair of 1 supporting cables for each drum and a load suspension means, the supporting cables of each cable drum being guided in pairs between the drum and the load suspension means with the cables in the or each pair at a spreading angle to one another, the mounting means comprising guide elements which act on the spread ends of the supporting cables and allow adjustment of the spreading angle, and, guide rails for the guide elements, the guide rails associated with each pair of supporting cables being arranged inclined towards each other.

The invention provides for the guide rails associated with the pairs of supporting cables each to be arranged inclined towards each other. This means that the spreading angle is automatically adjusted at least with load heights in an upper region. A change in the load height produces a force on the guide element which acts in the longitudinal direction of the guide rail in this region. As a result of this force, the guide element is displaced, with the force decreasing proportionally to the displacement of the guide element. Preferably, the guide element finally automatically adopts the position in which the force acting in the longitudinal direction of the guide rail is zero.

In this manner, the spreading angle in the above region is automatically kept approximately constant.

In one embodiment in which the spreading angle opens upwards, at least one right-hand winding and at least one left-hand winding is arranged on either side of the centre of the cable drum, the pairs of supporting cables being formed in each case of a supporting cable of the right-hand winding and a supporting cable of the left-hand winding. Each supporting cable of the pair of supporting cables is guided back towards the cable drum over deflecting rolls located on the load suspension means. The guide rails are arranged on either side of the longitudinal axis of the cable drum approximately at its height and extend in the 2 direction of the longitudinal axis of the cable drum.

In the case of a spreading angle which opens downwards, it is proposed that the pairs of supporting cables each be formed of supporting cables of the righthand windings or of the left-hand windings, and be guided in a plane extending transversely to the longitudinal axis of the cable drum. The guide rails in this embodiment extend transversely to the longitudinal axis of the cable drum. In this case too, therefore, the spreading angle is kept constant over a given region of the load height.

Expediently, the guide rails are each fastened to the supporting frame of the cable drum.

When using a single cable drum, it is advantageous if each pair of supporting cables is guided to the load suspension means over a roll arranged at the level of the cable drum.

In order to improve the cable guidance, cable grooves in which the supporting cables are guided are formed on the cable drum.

In order to simplify the design, each guide element can be moved along the guide rail only within a given length. This means that the length of the guide rail can be kept short. Furthermore, in this manner it is possible for the spreading angle to be limited to its maximum value only in a small predetermined region, so that a smaller spreading angle is possible for a lower load height, which results in a smaller load on the supporting cables.

one particular way of keeping the spreading angle automatically constant is by selecting the angle of inclination of the guide rails relative to one another such that the longitudinal extent of the guide rail with the 3 longitudinal direction of the fastened supporting cable forms an angle of 900 in a region within the given length.

Very easy movement of the guide elements is yielded if they are in the form of travelling mechanisms.

Expediently, the load suspension means is designed as a crossbar.

The invention will now be described by way of example and with reference to the accompanying drawings in which:

Figs. la-lc are front views of a fastening means for supporting cables of a lifting gear with guide rails arranged on the load suspension means; Fig. 2 is a cross-section through a lifting gear with cable drum and pairs of supporting cables with a spreading angle a which opens downwards; Fig. 3 is a front view of a lifting gear with cable drum and pairs of supporting cables which pass back to the cable drum over deflecting rolls, and, Fig. 4 shows front views of the arrangement of Fig. 3 with different lifting heights.

Figures la-lc show diagrammatically a fastening means for supporting cables 1 of a lifting gear 2, in which guide rails 4 inclined towards each other are arranged on a load suspension means 3. The load suspension means 3 is designed, for example, as a crossbar 3a.

As Figures la-lc show, guide elements 5 in the form of travelling mechanisms 5a can be moved in the longitudinal direction of the rails by means of the guide rails 4. of course, sliding carriages and the like are also conceivable as guide elements 5. The supporting cables 1 coming as pairs la 4 f rom a cable drum 6 (see Fig. 2) are fastened to the associated travelling mechanism 5a by their spread ends. The travelling mechanisms Sa thus act on the spread ends of the supporting cables 1 to adjust the spreading angle a.

Figures la-lc show to three different load heights, Fig. la showing the lowest load height. With the guide rails 4 inclined relative to the horizontal by an angle of inclination a, which is the same as the given maximum spreading angle a of the supporting cables, the angle 6 which the longitudinal extent of the guide rail 4 forms with the longitudinal direction of the fastened supporting cable 1 is greater than 90 degrees. In Fig. la, the travelling mechanisms lie against outer stops 7. With increasing load height, the condition is reached at which the longitudinal extent of the guide rail 4 and the supporting cable 1 forms an angle 6 of exactly 90 degrees, which is shown in Fig. lb. Upon a further increase in load height, however, as Fig. ic shows, there is no further reduction in the angle 6.

This is achieved by movement of the travelling mechanism Sa along the guide rail 4. This occurs automatically since, as the load height increases, a force acts on the travelling mechanism Sa and displaces the travelling mechanism until the angle between the longitudinal extent of the guide rail 4 and the longitudinal direction of the fastened supporting cable 1 is 90 degrees. This is the position in which the force component which acts in the longitudinal direction of the guide rail 4 is zero. This obviously applies only up to the load height at which the travelling mechanism Sa hits the inner stop 8. From this maximum load height onwards, further raising of the load would cause the spreading angle a of the pair of supporting cables 1, 1 to increase to beyond the given permissible limit.

It is therefore possible to increase the load height beyond what is otherwise the maximum permissible height by means of the rail-guided guide elements 5, always provided that a maximum permissible spreading angle a, which corresponds to a maximum safe cable load, is set for each supporting cable dependent on the cable diameter.

Fig. 2 shows a lifting gear 2 in cross-section which comprises a cable drum 6 having on either side a pair of supporting cables la, 1b, each of which is guided in a plane extending transversely to the longitudinal axis of the cable drum 6 at a spreading angle a which opens downwards. In this variant, the two pairs of supporting cables la, lb are deflected downwards over rolls 9, 10. The ends of the supporting cables are in turn fastened to the travelling mechanisms Sa which run in the guide rails 4, which are inclined towards each other and fastened to a crossbar 3a.

The pairs of supporting cables la, lb are each associated with right-hand windings or left-hand windings which are arranged on the cable drum 6. As Fig. 2 shows, the guide rails 4 extend transversely to the longitudinal axis of the cable drum 6. The longitudinal axes of the guide rails 4 all lie in a common plane, which is clearly defined by the pairs of supporting cables la, lb. Of course, it is also possible for the pairs of supporting cables la, lb to lie in planes parallel to each other.

A further variant can be seen in Figs. 3 and 4. Fig. 3 shows a cable drum 6 on which a right-hand winding 11 and a left-hand winding 12 on either side of the centre of the cable drum. The pair of supporting cables la which is guided downwards is recognisably formed of one supporting cable 1 of the right-hand winding 11 and one supporting cable 1 of the left- hand winding 12. The supporting cables are guided downwards at a spreading angle a, and then 6 guided back towards the cable drum 6 over deflecting rolls 13a, 13b located on the load suspension means 3. The ends of the pair of supporting cables la are in turn fastened to travelling mechanisms Sa, which are guided in guide rails 4. The guide rails 4 in this case are located at the level of the cable drum 6 and extend in the direction of its longitudinal axis.

The angle y between the respective cable guided first downwards and then upwards again is smaller than the maximum permissible spreading angle. The angle -y will change, depending on the height of the load, as Fig. 4 shows. The inclination of the guide rails 4 relative to one another is selected such that upon attaining the maximum spreading angle y the longitudinal extent of the guide rail 4 encloses an angle 6 of 900 with the longitudinal direction of the fastened supporting cable 1. Fig. 4 shows that upon a f urther increase in the load height the spreading angle T is kept constant by the fact that the travelling mechanism Sa move upwards in the guide rail 4. The angle 6 of 90 degrees between the longitudinal extent of the guide rail 4 and the longitudinal extent of the fastened supporting cable 1 is maintained, as can be seen in Fig. 4. The gain h in load height can be clearly seen in Fig. 4; the lifting gear can therefore be made smaller. only upon a further increase in the load height does an increase beyond the maximum permissible spreading angle y occur. In this variant too, the guide rails 4 are provided at their ends with stops 7, 8, against which the travelling mechanism Sa comes to rest upon reaching the associated height.

The travelling mechanism Sa is movable in each case within a predetermined distance along the guide rail. However, the ends of the pairs of supporting cables la, 1b do not necessarily have to be fastened directly to the travelling mechanisms Sa; it is also conceivable for a 7 deflecting roll to be arranged on the travelling mechanism 5a and for the actual fastening of the end of the supporting cable to be effected, for example, on the supporting frame of the cable drum 6. In the second variant configuration, the guide rails 4 may also be fastened to the supporting frame.

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Claims

1. A mounting means for the supporting cables of a lifting gear having at least one cable drum, at least a pair of supporting cables for each drum and a load suspension means, the supporting cables of each cable drum being guided in pairs between the drum and the load suspension means with the cables in the or each pair at a spreading angle to one another, the mounting means comprising guide elements which act on the spread ends of the supporting cables and allow adjustment of the spreading angle and guide rails for the guide elements, the guide rails associated with each pair of supporting cables being arranged inclined towards each other.

2. A mounting means as claimed in Claim 1, wherein the cable drum has at least one right-hand winding and at least one left-hand winding on opposite sides thereof, and at least one pair of supporting cables formed of a supporting cable of the right-hand winding and a supporting cable of the left-hand winding, wherein each supporting cable of the pair of supporting cables is guided back towards the cable drum over a deflecting roll located on the load suspension means and wherein the guide rails are arranged on either side of the cable drum at approximately the same vertical position as the drum.

3. A mounting means as claimed in Claim 2 wherein the guide rails are each fastened to a support frame which carries the cable drum.

4. A mounting means as claimed in Claim 1 wherein each pair of supporting cables is formed of supporting cables of a winding on a side of the drum and is guided in a plane extending transversely to the longitudinal axis of the cable drum at a spreading angle which opens downwards, and wherein the guide rails extend transversely to the 9 longitudinal axis of the cable drum.

W

5. A mounting means as claimed in Claim 4 wherein each pair of supporting cables is guided to the load suspension means over a roll arranged at the level of the cable drum.

6. A mounting means as claimed in any previous claim wherein the cable drum has cable grooves in which the supporting cables are guided.

7. A mounting means as claimed in any preceding claim wherein each guide element can be moved a given distance along the associated guide rail.

8. A mounting means as claimed in Claim 7 wherein the angle of inclination of each associated pair of guide rails relative to one another is selected such that the guide rail and the associated supporting cable encloses an angle of 900 when the guide element in a section within the given distance.

9. A mounting means as claimed in any preceding claim wherein the guide elements are in the form of travelling mechanisms.

10. A mounting means as claimed in any preceding claim wherein the load suspension means is designed as a crossbar.

11. A mounting means substantially as hereinbefore described and illustrated in the accompanying drawings.

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