EP0005099A1 - Mechanical travel-limiting device for winch - Google Patents

Abstract

Mechanical end-of-travel safety device for winch comprising two longitudinal elements (7.8) containing between them a winch (1) and which are joined by a first transverse element (12) carrying two pivoting envelopes (13,14) containing two calibrated springs , and by a second transverse element (17) carrying a yoke (18) and the envelopes (13,14) while a lever (29) is connected to a clutch control of the winch (1),

The invention is applicable to all winch devices, mainly telescopic lifting devices for construction sites.

Description

The subject of the invention is a limit switch safety device for all wire rope winches used on the various lifting and load displacement devices which are used on construction sites or in all other places. These winches are driven by a motor via a control lever clutch on which the safety device acts.

More precisely, the device of the invention has the role of preventing any excessive tension of the cable when the load driven by the winch encounters resistance, which generally occurs at the end of the lifting stroke, and of preventing any exaggerated unwinding of the cable. when the load is stopped by an obstacle during its descent, which generally takes place at the end of the descent stroke. The device of the invention can intervene at any point in the stroke of the load if the movement of the latter is not carried out without hindrance but it has no action on the operation of the winch when the load moves freely.

The state of the art in this field is illustrated by French patent N ° 77-23063. In the latter, a safety limit switch is added tee to the structure of a lifting device on the path of the metal cable between the winch and a first pulley for deflecting this cable.

The main object of the present invention is to provide a safety device designed to be combined with a clutch and a winch in order to constitute a complete compact block independent of any structure of any lifting device.

In addition, on lifting devices of the type of trolley material lifters moving on a ladder, it is frequent that the latter consists of several sections sliding telescopically into one another. When developing the ladder by sliding the sections, it is necessary to gradually supply the cable which extends from the winch to the top of the last section of the ladder.

Another object of the invention is to provide a device of the compact type mentioned above, which is improved to provide, by successive lengths of wire rope, automatically unwinding from the winch as the ladder is extended.

On a wire rope winch, associated with a three-position control lever clutch, with a limit switch safety device comprising a pulley carried by an oscillating yoke under the effect of two calibrated springs with successive actions and connected to the control lever by articulated levers, the main object of the invention is achieved by means of two spaced apart longitudinal elements containing between them the winch and extending beyond this on the same side as the wire rope; a first transverse element joins the longitudinal elements and carries, with a possibility of pivoting, a set of telescopic envelopes containing the calibrated springs; a second transverse element carries, with a possibility of pivoting, the yoke containing the pulley, however an articulated connecting member joins the envelopes and the yoke by transmitting to the latter the forces of the springs.

When the winch has a large width, the longitudinal elements of the frame are extended in opposite directions and are joined by two crosspieces serving to support and guide an orientable pulley for winding the wire rope which passes, first, by winding , on the pulley of the oscillating yoke.

The oscillating yoke and the clutch control lever are connected by articulated levers, a first lever of which is provided with two spaced stops capable of meeting and maneuvering the clutch control lever in order to put it back, after a determined stroke. , in its neutral declutching position, in one direction or in the opposite direction. One of these stops corresponds to the closing of the clutch for winding the cable and the other to its closing for the unwinding of the cable.

With the device described above, the second goal mentioned above is reached by means of a retractable part which allows the first lever and the control lever to be fixed at will when the latter is in the neutral disengaging position, however the connecting member is joined to the envelopes containing the calibrated springs using a coupling means which can be neutralized at will.

To better appreciate the invention we will now give a description of an exemplary embodiment.

• la figure 1 est une vue de dessus d'un ensemble combiné compact comprenant un dispositif de sécurité conforme à l'invention,
• la figure 2 est une vue en élévation et en coupe selon II-II de la figure 1 du même ensemble avec le dispositif en position neutre, les figures 3 et 4 sont des vues analogues à la figure 2 montrant respectivement les deux états de fonctionnement du dispositif de sécurité en fin de course basse et en fin de course haute de la charge,
• la figure 5 est une vue en élévation, analogue à la figure 2, montrant le dispositif de sécurité dans son état correspondant à l'allongement du câble métallique pendant le déploiement d'une échelle de levage sur un appareil muni d'une telle échelle.

Reference is made to the appended drawings in which:

• FIG. 1 is a top view of a compact combined assembly comprising a safety device according to the invention,
• Figure 2 is an elevational and sectional view along II-II of Figure 1 of the same assembly with the device in neutral position, Figures 3 and 4 are views similar to Figure 2 respectively showing the two operating states of the safety device at the low end and high end of the load,
• Figure 5 is an elevational view, similar to Figure 2, showing the safety device in its state corresponding to the extension of the wire rope during the deployment of a lifting ladder on a device provided with such a ladder.

In this example, a winch 1 supported above a base 2 is capable of being rotated by a motor (not shown) via 1 clutch 3 (omitted in FIG. 1 for clarity of the drawing ); this clutch 3 has a control lever 4 which can occupy a neutral disengaging position N, a clutch position M for winding the wire rope 5 of the winch and raising a load, a clutch position D for the unwinding of the cable 5 and the descent of a change under the retaining winch.

An end-of-travel safety device designated by the general reference 6 is designed to be combined with the clutch 3 and the winch 1 and to constitute with them a compact and complete assembly. This device 6 comprises two longitudinal elements 7, 8 spaced so as to contain between them the winch 1. These elements 7, 8 are advantageously fixed securely to the flanges 9, 10, between which is the drum 11 of the winch, and they are extend outside the latter on the same side as the wire rope 5. In Figures 2 to 4, the longitudinal element 8 is not shown.

A first transverse element 12 extends between the longitudinal elements 7 ₉ 8 and it carries a set of two telescopic envelopes 13, 14 superimposed, closed at their ends, each containing a calibrated spring, respectively 15, 16 whose degree of compression is adjustable by means of adjustment known per se. These springs 15, 16 are arranged in extension of one another to act as will be explained below. In the example described here, the envelopes 13, 14 constitute an assembly capable of pivoting thanks to the fact that the transverse element 12 is mounted with freedom of rotation in the longitudinal elements 7, 8. As a variant, the envelopes 13, 14 could be pivotable relative to the transverse element 12 which would be fixed relative to the longitudinal elements 7, 8.

More specifically, the lower part of the envelope 13 is attached to the transverse element 12; the sliding upper cap of this envelope 13 carries the lower part of the envelope 14 which ends in a sliding upper cap.

A second transverse element 17, further away from the winch 1 than the first transverse element 12, extends between the longitudinal elements 7, 8. It is supported by the latter, free to rotate about a transverse axis 17 A. This second transverse element 17 carries a yoke 18 in which is mounted, free in rotation, a pulley 19 for guiding the wire rope 5. The pulley 19 can therefore perform oscillatory movements with the yoke 18 relative to the transverse axis 17 A .

A connecting member 20 functionally brings together the assembly composed of telescopic envelopes 13, 14 and the yoke 18 in order to transmit thereto the forces created by the springs 15, 16. In the present example, the connecting member 20 is a U-shaped profile in the core of which an opening 21 is formed.

For the spring 16, the sliding upper cap 22 of the casing 14 extends through the opening 21 until the stops 23 fixed at its lower free end are applied against the ends of the wings of the profile 20. In addition, the latter is articulated at 24 at one of its ends on the yoke 18 and at 25, at its opposite end, on a plate 26 movable in oscillation with this yoke 18.

Preferably, the yoke 18 and the pulley 19 are offset relative to the casings 13, 14 and the calibrated springs 15, 16 in the width which separates the two longitudinal elements 7, 8 so that the cable 5 finds a clear path from winch 1.

The control lever 4 of the clutch 3 is generally a vertical lever.

It is integral in its movements with a horizontal control lever 27 (omitted in Figure 1). Two other levers 28 and 29 articulated together at 30 functionally connect the yoke 18 and the horizontal lever 27. The first lever 28 is equipped with two spaced stops 31, 32 which are arranged to meet the control lever 27 and to return it to its neutral declutching position from any one of the two clutch positions, by moving a determined stroke, in one direction or in the opposite direction. The second lever 29 is integral with the oscillating movements of the yoke 18. It can therefore be fixed, either directly to the latter, or to the plate 26, as in the present example, according to the relative arrangement of the different parts.

• La position normale des organes pendant la marche du treuil est visible sur la figure 2. Le ressort 15 est détendu tant que la tension du câble métallique 5 ne dépasse pas une valeur prédéterminée. Le ressort 16 est comprimé tant que la tension du câble n'est pas inférieure à une valeur prédéterminée.

As just described, the device operates as follows:

• The normal position of the members during the operation of the winch is visible in FIG. 2. The spring 15 is relaxed as long as the tension of the metal cable 5 does not exceed a predetermined value. The spring 16 is compressed as long as the cable tension is not less than a predetermined value.

When, for the retained descent of a load, the control lever 4, and consequently the lever 27, has been put in its position D of unwinding the wire rope 5, the latter exerts on the pulley 19 a force which holds the compressed spring 16. When this tension disappears as a result of stopping the descent of the load, generally at the end of the lower stroke, the spring 16 pushes the bonnet 22, by means of the connecting member 20, which causes the yoke 18 and lever 29 with respect to axis 17 A.

The lever 28 is pushed back at the same time so that the stop 31 meets the control lever 27 at its position D and pushes it back to its position N. The disengagement thus produced stops the unwinding of the cable 5. For the rise of a load, the control levers 4 and 27 are set to their position M. When the load is stopped in its movement, generally at the end of the high stroke, the tension of the cable 5 rises until the force exerted on the pulley 19 causes pivoting of the yoke 18 and of the lever 29. It follows that the connecting member 20 is applied against the stops 23 and that, via the cap 22 and the casing 14, the spring 15 is compressed inside the envelope 13. During this movement, the lever 28 is pulled so that the upper stop 32 meets the control lever 27 at its position M and pushes it back to its disengaged position N. The winch is therefore stopped.

When the winch 1 is very wide, the longitudinal elements 7 and 8 are extended on the other side of the winch 1 and joined by two crosspieces 33 and 34. The crosspiece 33 is used for mounting the pivot 35 of an orientable pulley 36; the latter is held in a yoke 37 provided with a support roller 38 which rolls on the cross-member 34. Thus the cable 5 is guided during its winding on the winch drum.

It may happen that a winch fitted with a safety device according to the invention is installed on a lifting device with a telescopic scale which is used to guide a carriage. When developing this scale, it is necessary to unwind gradually the cable 5. It is possible to perfect the device that has just been described so that this unwinding of the cable is done automatically as and when required.

This improvement consists in making the coupling which exists between the connecting member 20 and the envelopes containing the calibrated springs neutralizable at will.

In this example (Figure 4), the neutralizable coupling means is constituted by the cap 22 provided with the stops 23 which are applied against the end face of the wings of the U-shaped section 20 constituting the connecting member. The stops 23 have a limited length in the direction of the perimeter of the cap 22 so that by rotating the latter inside the opening 21, one can place the stops 23 inside the wings of the profile. The spring 16 is fully relaxed when the stops 23 approach the web of the profile as can be seen in FIG. 4. In addition, a retractable part 39 allows the first lever 28 and the control lever 27 to be joined at will. For example, a bent plate 39 is articulated by one end around a pivot 40 disposed at the end of the control lever 27. When this plate 39 is placed parallel to the lever 28, its bent part 41 can be engaged just in below the stop 32 of the latter when the control lever 27 is in its neutral position N disengage and that the stop 31 is located just below this lever.

When the safety device is in this state, the springs 15 and 16 being put out of service, any tension even exerted on the pulley 19 by the cable 5 during the deployment of the telescopic ladder rotates the yoke 18 of this pulley around the axis 17 A in a direction which causes the descent of the lever 28. Immediately the stop 32 meets the bent part 41 and pushes the control lever 27 from its position N to its position D, as shown in FIG. 5. The winch 1 is driven in the direction of the unwinding of the cable 5. As soon as the tension disappears in the latter , the weight of the pulley 19 and the yoke 18 causes a reverse return movement during which the stop 31 returns the control lever 27 to its position N.

Returning to FIG. 2, it will be seen that the relative arrangement of the geometric axes of pivoting or oscillation of the moving parts (yoke 18, casings 13, 14 of the calibrated springs) is chosen so that the moments of the forces brought into play remain substantially constant despite the displacement of the yoke 18 under the effect of the cable or the springs. Naturally, the metal cable 5 can be replaced by a cable of another nature or by a chain without departing from the scope of the invention.

As we have already said, the device described above is double acting. When its role is to stop the winch at the end of the load's high stroke, it prevents excessive tension of the cable. Of course, any cause producing an excessive tension of the latter also causes the pivoting of the yoke 18 and, consequently, the disengagement of the winch. In particular, an excessive load attached to the cable produces this result. The device of the invention acts therefore also as a safety means preventing overloading of the cable and the winch as well as of the apparatus on which the winch and the device of the invention are installed. Since this protection, avoiding excessive tension of the cable and overloading of the assembly, is greater than that which consists in preventing excessive unwinding of the cable, one could, as a variant, use the device of the invention only for this function by removing the casing 14 and the spring 16. In this case, the connecting member 20 should be arranged to press directly on the sliding cap of the casing 13. Only the stop 32 of the lever 28 would be used to return the control lever 27 from its position M to its position N as shown in FIG. 4. In this simpler aspect, the device of the invention offers safe protection against the greatest risk, that is to say the risk of overloading, while retaining its compactness and easy combination with a winch.

Claims (13)

1. Safety device for a wire rope winch associated with a three-position control lever clutch, comprising a pulley carried by an oscillating yoke under the effect of at least one calibrated spring subjected to the tension of the cable, this yoke being functionally connected by levers articulated to the clutch control lever, characterized in that two spaced apart longitudinal elements (7, 8) containing between them the winch (1) extend in the same direction as the wire rope (5) , a first transverse element (12) joins the longitudinal elements (7, 8) and carries with a pivoting possibility at least one telescopic casing (13) containing a calibrated spring (15), a second transverse element (17) joins the elements longitudinal (7, 8) and carries with a possibility of oscillation a yoke (18) of a pulley (19) for guiding the metal cable (5), an articulated connecting member (20) joining functionally the yoke (18) and the envelope (13) by transmitting to this envelope (13) the force exerted on the yoke (18) by the tension of the cable (5). 2. Safety device according to claim 1 for a wire rope winch associated with a three-position control lever clutch, comprising a pulley carried by an oscillating yoke under the effect of two calibrated springs with successive actions according to the cable tension. , this yoke being functionally connected by levers articulated to the clutch control lever, characterized in that two spaced apart longitudinal elements (7, 8) containing between them the winch (1) extend the same side as the metal cable (5), a first transverse element (12) joins the longitudinal elements (7, 8) and carries with a possibility of pivoting a set of telescopic envelopes (13, 14) containing calibrated springs (15, 16), a second transverse element (17) joins the longitudinal elements (7, 8) and carries with a possibility of oscillation a yoke (18) of a pulley (19 ) for guiding the metal cable (5), an articulated connecting member (20) functionally joining the yoke (18) and the envelopes (13, 14). 3. Device according to claim 2, characterized in that the telescopic envelopes (13, 14) constitute an assembly comprising for the spring (15) for upper end-of-travel safety a lower part associated with the first transverse element (12), a sliding top cap, and for the bottom limit safety spring (16), a lower part carried by the sliding top cap of the casing of the other spring and a sliding top cap (22) associated with the articulated connecting member (20). 4. Device according to claim 3, characterized in that the connecting member (20) is constituted by a U-shaped profile having a passage opening (21) of the cap (22) forming part of the telescopic envelope (14) of the low limit travel safety spring (16), this cap (22) having two opposite stops (23) arranged to be applied against the ends of the wings of the U-shaped profile under the effect of the compressed spring (16). 5. Device according to claim 2, characterized in that the connecting member (20) is articulated on the yoke (18) at one of its ends and on a plate (26) at its opposite end, this plate ( 26) being carried by the second transverse element (17) and made mobile with this yoke (18). 6. Device according to claim 2, characterized in that the yoke (18) and all of the telescopic envelopes (13, 14) of the calibrated springs are offset, one relative to the other in the width of the winch ( 1) between the longitudinal elements (7, 8). 7. Device according to claim 2, characterized in that the connecting member (20) is functionally joined to the envelopes (13, 14) of the calibrated springs using a coupling means that can be neutralized at will, however the control lever (27) of the clutch (3) and the lever (28) of the safety device acting directly on this control lever (27) are arranged to be joined at will by a retractable part when the control lever ( 27) is in the neutral declutching position. 8. Device according to claims 4 and 7 together, characterized in that the cap (22) is freely engaged in the opening (21) of the connecting member (20) and the stops (23) have a limited length in perimeter direction of the cap (22) so that a rotation of the latter makes it possible to release the stops (23) from the ends of the wings of the U-shaped profile and to let them penetrate between these wings. 9. Device according to claim 7, characterized in that the control lever (27) of the clutch (3) is provided at its free end with a plate (39) pivotally mounted around a pivot (40) and can be placed parallel to the lever (28), this plate (39) extending to below a stop (32) of the lever (28) when the control lever (27) is located just above a stop (31) when it occupies its neutral declutching position, the stops (32) and (31) being respectively thrust stops of the control lever (27) from two opposite clutch positions towards its neutral disengagement position under the effect of the lever (28). 10. Device according to any one of claims 1, 2 characterized in that the longitudinal elements (7, 8) are extended on the other side of the winch (1) and their extensions are joined by two crosspieces (33, 34) which serve respectively to support and guide a pulley (36) for guiding the winding of the cable (5) on the drum (11) of the winch (1).

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