EP0082046A1 - Lifting tackles - Google Patents

Abstract

1. A tackle comprising pulley-block means (9) having an upper block (6) carried by a frame (10) and a lower block (27) carrying a hoisting hook (15) or like member and suspended from below the upper block (6) through at least one flat flexible line (5) passing around return pulleys (4) which are carried by the two blocks (6, 27) and at least one end (23) of which is attached to the drum (21) of a drum-pulley (2) driven by a rotary driving member (1), characterized in that the upper block (6) is mounted on the frame (10) in such manner as to be freely pivotable about a horizontal axis (X-X) substantially tangent to upper parts of grooves of two successive return pulleys (4), namely that pulley (4b) carried by the upper block (6) which the flat flexible line reaches first in travelling away from the drum-pulley (2) and that pulley (4) which succeeds the last-mentioned pulley in a direction toward the drum-pulley (2).

Description

The invention relates to a hoist which is provided with hauling formed from an upper yoke carried by a frame and from a lower yoke carrying a lifting hook or the like and suspended below the upper yoke by means of a flexible link which passes over return pulleys carried by the two yokes and at least one end of which is anchored to the drum of a pulley-drum driven by a rotary drive member.

The above rotary motor member can be of the manual, electric, pneumatic or hydraulic type. By "member similar (to a lifting hook)" is meant in particular an electromagnet, suitable for lifting ferrous masses, or a suction cup system, suitable for lifting windows or similar loads.

In the usual hoists of the kind defined above, the flexible link is generally constituted by a chain and the rotary motor member by a nut or pulley whose groove is dimpled in the shape of the chain links and on which the chain only rolls up on a fraction of a turn. Beyond this nut (on the side opposite to the lifting hook), the chain hangs more or less freely, encumbering the space located below the hoist, west received in a bulky bin which creates difficulties of housing and d balancing of the hoist. In other hoists, the chain is replaced by a round cable, but this solution also has many disadvantages. known to technicians such as overall dimensions of the pulley-drum in width (see US-A-4,042,213), fragility, need for a cable guide, etc.

In tackles without hauling, it has often been proposed to use a flat flexible link (textile strap, steel strip, metal braid). We can cite in this respect the German patents or patent applications 682,482, 1,120,093, 1,152,237, 2,312,604, 2,700,948, the French patent 996,125 and the US patent 3,452,964. In these known hoists, the flat flexible link is wound on the drum pulley over a small height since the thickness of this flexible link can be maintained, that is to say the thickness of each winding turn on the pulley-drum, at relatively low values since one can play on the width of this flexible link to increase its tensile strength.

We know that loads suspended from a hoist are generally subject to a certain lateral swing. This phenomenon has hitherto prevented the replacement of cables or chains, on tackle hoists formed by an upper yoke and a lower yoke, by flexible flexible links because the aforesaid lateral rocking would subject these flexible flexible links to efforts lateral which would tend to bring them out of the various pulleys which guide them.

The object of the invention is to arrange the hoists of the kind defined in the preamble in such a way that they can be fitted with flexible flat links while being suitable without any drawback for the swinging of the suspended load.

To achieve this goal, the hoist of the kind defined above is essentially characterized, according to the invention, in that, the flexible link being flat, the upper yoke is mounted on the chassis so as to be able to rotate freely along a horizontal axis substantially tangent to the upper parts of the grooves of two successive deflection pulleys, namely the deflection pulley the upper yoke that the flat flexible link reaches first arriving from the drum pulley and the return pulley which follows it towards the drum pulley.

Thanks to this construction, the lateral swaying of the load results in an oscillation of the upper yoke around the above horizontal axis, this oscillation simply having the effect of twisting or slightly untwisting the flat flexible link without imposing on it efforts lateral which would tend to bring it out of the various pulleys which guide it.

The invention will now be described in more detail using various embodiments which are shown diagrammatically in the accompanying drawings.

FIG. 1 of these drawings represents a hoist according to a first embodiment of the invention, in longitudinal vertical section along the line I-I in FIG. 2.

FIG. 2 shows the hoist of FIG. 1 in section through vertical planes offset along the line II-II of FIG. 1.

FIG. 3 represents a detail of the same hoist, in vertical section along the line III-III of FIG. 1.

Figures 4 to 9 show, similarly to Figure 1, hoists according to as many different embodiments of the invention.

Figures 10 and 11 show, by views similar to those of Figures 2 and 3 respectively, hoists with straps mounted in parallel.

FIG. 12 represents a balancing device for the hoist with two straps of FIGS. 10 and 11.

Figures 13 and 14 show balancing devices similar to that of Figure 12, but for hoists with three straps and four straps respectively.

Figure 15, finally, represents in half-section axial a variant of the pulleys.

The hoist shown in Figures 1 to 3, comprises a frame 10, formed of two vertical flanges 16, 17 which are rigidly assembled using, for example, horizontal rods such as 18, a cross member 28 and spacers tubular 20.

The flexible link of the hoist, which is flat, is constituted by a flat textile strap (or metal braid) 5 and the rotary drive member of the hoist is constituted by a pulley-drum 2 made of a drum 21 and two cheeks 22 and housed between the two flanges 16 and 17. One of the ends 23 of the strap 5 is anchored, for example using a key 24, to the drum 21 of the drum pulley 2 whose cheeks 22 have a diameter D sufficient for them to contain the strap 5 wound as much as possible on the drum 21, as can be seen in section in FIG. 2 (the strap 5 then leaving from the drum pulley 2 in the manner shown in solid lines at Figure 1).

The pulley-drum 2 is keyed onto a shaft 25 which constitutes the output shaft (low speed shaft), suitably elongated, of an electric gear motor 1. As is apparent in particular from FIG. 2, the latter, which is of the type with built-in brake, is mounted on the outer face of the flange 16 while its shaft 25 crosses the two flanges 16 and 17 and protrudes beyond the flange 17.

Leaving the drum pulley 2, the strap 5 passes over several return pulleys 4 and its end 26, opposite the end 23, is hooked to the chassis 10, as described below, so that the strap 5 can support a muffle 9 with one, two or three strands, a lifting hook 15 being mounted on this muffle 9. This comprises an upper yoke 6 carried by the frame 10 and a lower yoke 27 suspended below the upper yoke 6 via the strap 5. According to the embodiment shown in FIG. 1, the strap 5 passes successively over a first deflection pulley 4a, the axis of which is carried directly by the frame 10, over a second deflection pulley 4b mounted in the upper yoke 6, over a third deflection pulley 4c mounted in the lower yoke 27, on a fourth idler pulley 4d mounted in the upper yoke 6 and on a fifth idler pulley 4th mounted in the lower yoke 27, its end 26 being fixed to the upper yoke 6 in any suitable manner, for example using a transverse pin 34. It goes without saying that such hauling could be replaced by hauling of any other equivalent type, examples of which will be described below with reference to FIGS. 4 to 9.

According to the invention, the upper yoke 6 is mounted on the chassis 10 so as to be able to rotate freely around a horizontal geometric axis XX substantially tangent to the upper part of the groove of that 4b of the pulleys 4 of the upper yoke 6 that the strap 5 reaches the first from the pulley-drum 2 as well as at the upper part of the groove of the pulley 4a which follows it towards the pulley-drum 2 (see FIG. 1). This horizontal axis XX is materialized by an articulation pin 44 which passes through aligned holes, formed in crosspieces 19 of the upper yoke 6 as well as in the crosspiece 28 and in one of the tubular spacers 20 of the chassis 10. This the latter, which consists of two approximately rectangular flanges 16 and 17, is provided with a notch 29, at its lower part and below the upper yoke 6. The flanges 16, 17 carry between them, substantially at the same height , on one side the pulley-drum 2 and, on the other side, the haul 9. This facilitates the lateral deflections of the lower yoke 27 and makes it possible to raise the hook 15 very high relative to the chassis 10.

The hoist preferably comprises, as load limiter, a device 7 suitable for reacting when the tension of at least one strap strand, in this case the strand between the pulleys 4a and 4b, exceeds a predetermined threshold, preferably adjustable. According to the embodiment of Figure 1, the load limiting device 7 comprises a roller 30 which rests on the upper face of the strap 5 between the pulleys considered 4a and 4b, this roller 30 being guided along a vertical path (or approximately vertical) and being biased downwards by a spring 31. For this purpose, the horizontal axis of the roller 30 is carried by a rod 32 guided. in a vertical sleeve 33 and threaded, opposite, the roller 30, so as to receive a nut and a lock nut 8. The latter serve as support for a cup 35, the spring 31 being a compression spring which acts on this cup 35 by reacting on the support 36 of the sleeve 33. By its end free in the form of a ramp 37, the rod 32 actuates an electrical limit switch 13. This contact 13 is mounted on the supply circuit of the geared motor 1 so as to stop the latter when the load applied to the hook 15 exceeds a determined threshold, i.e. when the t ige 32 crosses upwards a determined height with respect to the chassis 10. The above threshold can be adjusted using the nut and its lock nut 8 which determine the tension of the spring 31.

The supply circuit of the geared motor 1 is completed by limit switches 38 and 39 which cooperate with a nut 40 mounted on the threaded free end of the shaft 25 of the geared motor 1 and which respectively determine the limit positions of the hook 15, up and down. These limit switches 38 and 39 are mounted on a strip 3 inside an electrical cabinet 11 mounted on the chassis 10. When crossing the shaft 25, this cabinet 11 can be made watertight using a filling 41.

Just use a gear motor 1, to built-in brake, explosion-proof type and accommodating in an explosion-proof box 11 the contacts 13, 38, 39 and other electrical components of the geared motor supply circuit 1, to have a hoist having an explosion-proof and non-sparking character .

The hoist according to the invention can be of the type placed, hung or suspended from a carriage. It is this latter possibility which has been shown schematically in broken lines in FIG. 2 where a carriage 12 rolls on a monorail 42, the hoist being suspended from this carriage by means of suspension pins 14, passing through the tubular spacers 20 .

A hoist is thus obtained, the strap 5 of which is held taut between its ends 23 and 26, by its winding in successive spiral layers on the drum pulley 2, the limits of the winding being shown schematically, in broken lines and in solid lines, respectively. in FIG. 1, by the extreme positions of the strap 5 when it leaves this pulley-drum 2.

When the load suspended on the hook 15 tends to swing transversely, this results in an oscillation of the lower yoke 27, facilitated by the notch 29, and consequently by an oscillation of the upper yoke 6 around the horizontal axis XX and by a slight twist of the part of the strap 5 between the return pulleys 4a and 4b.

When the load suspended on the hook 15 exceeds a safety threshold, the tension of the strap strand 5 comprised between the return pulleys 4a and 4b has, at the level of the roller 30, a vertical component sufficient to overcome the action of the spring 31. This results in an uplift of the roller 30 and of the rod 32, the ramp-shaped end 37 of which leaves the electrical contact 13, which cuts off the supply of the gear motor 1 in the direction of ascent. Just reduce the load to allow the spring 31 to lower the rod 32 until its ramp-shaped end 37 returns to touch the contact 13 and restore the power to the gear motor 1.

The embodiment of FIG. 4 differs from that of FIG. 1 by the fact that the two ends (designated by 23 and 26 in FIG. 1) of the strap 5 are anchored to the drum of the drum pulley 2 by forming a loop of which two strands are superimposed on this drum and on the return pulleys 4a and 4b and then separate into an upper strand and into a lower strand. Leaving the pulley 4b, the upper strand passes over two pulleys of the upper yoke 6, that is to say over a pulley 4d identical to that of FIG. 1 and over a pulley 4f whose axis 43 has the same location that the spindle 34 of Figure 1. Leaving the pulley 4b, the lower strand goes directly to the single pulley 4g of the lower yoke 27, where it is joined by the upper strand. When reaching the 4g pulley, the two upper and lower strands form an angle that is sufficiently open so that they do not twist between the yokes 6 and 27. It should be noted that the 4g pulley does not rotate. only if the upper and lower strands undergo different elongations from one another.

The embodiment of FIG. 5 differs from that of FIG. 1 by removing the pulley 4d on the upper yoke 6 and by replacing the two pulleys 4c and 4e with a single pulley 4g on the lower yoke 27. The strap 5 therefore passes from the pulley 4b to the pulley 4g before reaching the anchoring pin 34 on the upper yoke 27. As in the case of FIG. 4, the two strands of the strap 5 which arrive at the pulley 4g form an angle sufficiently open so that they do not twist between the yokes 6 and 27.

The embodiment of FIG. 6 differs from that of FIG. 1_by replacing the two pulleys 4c and 4e by a single pulley 4g on the lower yoke 27 and by anchoring the end 26 of the strap 5, not on the upper yoke 6, but on the lower yoke 27, for example using the spindle 34. The strap therefore passes successively on the pulley 4b of the upper yoke 6, on the single pulley 4g of the lower yoke 27, on the pulley 4d of the upper yoke 6 before anchoring to the lower yoke 27 by its end 26.

Figures 7 to 9 illustrate the variant mentioned above, where the hoist is hung using a hook 45 which is fixed to the frame 10 and which is visible only in Figure 7, Figures 8 and 9 being truncated at their upper part. In this case, the muffle 9 is arranged, not at the same height as the drum pulley 2 as in the embodiments of Figures 1, 4, 5 and 6, but below it. Consequently, the spindle 44 embodying the axis X-X is placed directly above the shaft 25, as close as possible to the lower edge of the cheeks 22 of the drum pulley 2.

According to the embodiment of Figure 7, the two ends of the strap 5 are anchored to the drum 21, as in the embodiment of Figure 4, forming two strands which are superimposed here only on the drum 21. The strand left (according to the drawing) passes over pulleys 4a and 4b arranged as in the previous embodiments while the right strand passes over pulleys 4'a and 4'b similar to these pulleys 4a and 4b and symmetrical with those respectively -this relative to a vertical plane YY passing through the axis of the suspension hook 45 and through the axis of the shaft 25. The two strands meet on the single pulley 4g of the lower yoke 27 at an angle sufficient open to prevent strap 5 from twisting.

The embodiment of FIG. 8 is identical, as regards its upper part, to the embodiment of FIG. 7 and, as regards its lower part, to the embodiment of FIG. 5.

The embodiment of FIG. 9 is identical, as regards its upper part, to the mode of embodiment in FIG. 7 and, as regards its lower part, in the embodiment of FIG. 6.

In the embodiment of Figures 1 to 3, as indeed in those of Figures 4 to 9, it was assumed that the hoist according to the invention only included a strap 5 passing over a single pulley-drum 2 and a single set of deflection pulleys 4. In fact, this hoist could comprise in parallel at least two such straps 5 wound respectively on as many pulley-drums wedged on the same shaft 25. By way of example, FIGS. 10 and 11 illustrate, by views similar to those of FIGS. 1 and 3, the case of a hoist comprising two straps 5 and 5a wound respectively on two drum pulleys 2 and 2a and with which are associated two upper yokes 6 and 6a, mounted on individual pins 44 and 44a.

To balance the two straps 5 and 5a, it is advantageous to anchor their ends 26 and 26a using a lifting beam such as 46 (Figure 12). In the case where the hoist includes three straps 5, 5a, 5b in parallel, one could likewise anchor their ends 26, 26a and 26b using a system with two spreaders such as 46 and 46a (Figure 13). In the case where the hoist includes four straps 5, 5a, 5b, 5c in parallel, one could still anchor their ends 26, 26a, 26b and 26c using a system with three spreaders such as 46, 46a and 46b (figure 14). Thanks to this spreader system, the loads are evenly distributed on the straps, even if the useful lengths of these straps are not exactly the same.

As shown in axial half-section in Figure 15, to avoid wear of the strap 5 on its edges, it is advantageous to constitute the pulleys 4 so that their cheeks 47 are mounted idly on the axis 48 of these pulleys, for example using individual bearings 49, independently of the body 50 of this pulley 4, which is mounted on the axis 48 using for example bearings. 51. In addition, it is advantageous, for the same purpose, to give the table or external surface 52 of the body 50 a convex shape.

• - faible prix de revient ;
• - faible encombrement ;
• - élimination des guide-câbles usuels ;
• - absence de décalage du crochet 15, entre la position basse et la position haute de sa course, le levage et la descente de ce crochet 15 se faisant donc toujours sur un même axe parfaitement vertical ;
• - lorsque le palan est utilisé en type anti-déflagrant ou anti-étincielles, absence de risque d'étincelles entre le lien souple 5, lorsqu'il est constitué par une sangle textile, et les parties métalliques du palan (poulie-tambour 2, poulies de renvoi 4, etc...) ;
• - très faible "hauteur perdue" (distance entre le haut du palan et le crochet 15 en position haute), selon les modes de réalisation des figures 1 à 6 ;
• - possibilité d'utiliser les mêmes éléments pour construire un palan à levage par l'intermédiaire d'une moufle à plusieurs brins, conforme à l'invention, et un palan à levage direct (sans moufle) ;.
• - diminution de la vitesse du crochet 15, de sa position haute à sa position basse, et vice versa, en raison de la variation progressive du diamètre d'enroulement sur la poulie-tambour 2.

Whatever the embodiment adopted, a hoist is obtained which has the following advantages in particular:

• - low cost price;
• - small footprint ;
• - elimination of the usual cable guides;
• - Absence of offset of the hook 15, between the low position and the high position of its travel, the lifting and lowering of this hook 15 is therefore always done on the same perfectly vertical axis;
• - when the hoist is used in explosion-proof or anti-sparking type, no risk of sparks between the flexible link 5, when it is constituted by a textile strap, and the metal parts of the hoist (pulley-drum 2, return pulleys 4, etc ...);
• - very low "height lost" (distance between the top of the hoist and the hook 15 in the high position), according to the embodiments of Figures 1 to 6;
• - possibility of using the same elements to build a hoist with lifting by means of a muffle with several strands, according to the invention, and a hoist with direct lifting (without muffle);
• reduction in the speed of the hook 15, from its high position to its low position, and vice versa, due to the progressive variation of the winding diameter on the drum pulley 2.

The invention is obviously not limited to the embodiments shown but encompasses all the variants. In particular, it would be possible to articulate around the axis XX, not the only upper yoke 6, but the entire frame 10 of the hoist, by means of the upper spacers 20 for example, in order to allow good winding of strap 5 on the drum pulley 2, and also in the most general case, on the return pulleys 4.

Claims (8)

1 .. Hoist which is provided with a hauling system (9) formed of an upper yoke (6) carried by a frame (10) and a lower yoke (27) carrying a lifting hook (15) or member similar and suspended below the upper yoke (6) by means of a flexible link (5) which passes over deflection pulleys (4) carried by the two yokes (6,27) and of which at least one end (23) is anchored to the drum (21) of a drum pulley (2) moved by a rotary motor member (1), characterized in that, the flexible link (5) being flat, the upper yoke (6) is mounted on the chassis (10) so that it can rotate freely along a horizontal axis (XX) substantially tangent to the upper parts of the grooves of two successive idler pulleys (4), namely the idler pulley (4b) of the upper yoke (6) that the flat flexible link (5) reaches the first from the drum pulley (2) and the return pulley (4a) which follows it towards the drum pulley (2). 2. Hoist according to claim 1, characterized in that the chassis (10) consists essentially of two flanges (16,17) approximately rectangular carrying between them, substantially at the same height, on one side, the pulley-drum ( 2) and, on the other side, the hauling system (9), which chassis is provided with a notch (29) below the upper yoke (6). 3. Hoist according to one of claims 1 and 2, characterized in that the frame (10) is mounted so as to be able to rotate freely along the horizontal axis (X-X). 4. Hoist according to claim 1, characterized in that the frame (10) carries a suspension hook (45) above the drum pulley (2) and the upper yoke (6) below the pulley- drum (2). 5. Hoist according to any one of claims 1 to 4, characterized in that it comprises at least two flexible flexible links (5, 5a) with their pulleys- individual drums (2,2a) wedged on the same shaft (25) driven by the drive member (1). 6. Hoist according to claim 5, characterized in that, by their end opposite to the pulleys-drums (2, 2a), the flexible flat links (5,5a) are anchored by means of a lifting beam system (46 ). 7. Hoist according to any one of claims 1 to 6, characterized in that the pulleys-deflection drums (4) have cheeks (47) capable of rotating each independently of their body (50), the outer surface (52 ) of it being curved. 8. Hoist according to any one of claims 1 to 7, in which the or each pulley-drum (2) is wedged on the output shaft (25) of a gear motor (1), characterized in that the motor-reducer (1) is of the explosion-proof type and in that the electrical components (13,18,39) of the supply circuit of the motor-reducer (1) are housed in an explosion-proof box.

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