EP0536060B1 - Crane jib which folds automatically - Google Patents

Abstract

The jib (10) comprises a jib base (11), an intermediate jib-folding element (12) and a jib tip (13), which are articulated to each other (at 14, 15) at the level of their lower members. The intermediate element (12) is connected to the jib base (11) by a motorised member (36) controlling its pivoting about the axis of articulation (14). The jib tip (13) is connected to the jib base (11) by a coupling assembly (40) having three articulated members (41, 42, 43), the central member (41) of this assembly being connected by articulation to a fixed point of the intermediate element (12) and causing the jib tip (13) to pivot about the axis of articulation (15). Application to the production of automatically erected tower cranes. <IMAGE>

Description

The present invention relates to the field of self-erecting cranes, in particular tower cranes used on building construction sites and public works, cranes which must be folded frequently for their transport on the road from one site to another, or from one location to another, in the best possible conditions of speed and security, without manual intervention. More specifically, this invention relates to an automatically folding boom for this type of crane, and more particularly still it relates to a device for folding / unfolding a boom made of several elements, which makes it possible to pass from a working position, with the jib elements aligned, in a folded position for transporting the crane as a whole, and vice versa from the folded transport position in the working position.

Both for foldable mast tower cranes and for telescopic mast tower cranes, with automatic assembly, many solutions exist for folding the boom into the crane transport position.

According to a first type, described for example in French patent No. 2,306,158, the boom comprises two elements, respectively an arrow foot articulated at the head of a telescopic mast and an arrow point articulated at the front end of the boom foot, while a cable of constant length connects a fixed point of the head of the mast to a fixed point of the arrowhead, so that during the telescoping of the mast the arrow passes from a folded position to the aligned working position and vice versa. This boom folding device requires that the crane is also equipped with a set of punches and tie rods used to raise the boom when the mast is telescoped. In this embodiment, the cable of constant length and the set of punches and tie rods must be adjusted periodically, in particular to compensate for the permanent elongation of the cables which changes over time.

According to a second type, described for example in French Patent No. 2,550,176, the boom articulated at the top of a mast is made of two or more elements articulated to each other, and a rod coupling system, arranged at each articulation and controlled by a tie rod connecting a member of said coupling system to a fixed point on the top of the mast or of a jib element, ensures the unfolding or folding of the jib during the telescoping of the mast in the case the latter is telescopic, or independently during boom lifting. Unlike the previous device, this device makes it possible to obtain and maintain good accuracy over time; nevertheless it presents some constraints which limit its good use to cranes with telescopic mast, because when the mast is not telescopic the control of the lifting of the boom is carried out by carrying out a hauling between the rear retaining cable and the rotating chassis of the crane and by controlling hauling by a mounting winch, which complicates the realization and affects the accuracy of the assembly.

According to yet a third type, described for example in French Patent No. 2,368,430, the boom articulated at the top of a mast is produced by at least two boom elements interconnected in an articulated manner by means of a boom folding section. In the embodiment described by the cited document, the folding section has the function of laterally folding the second part of the boom against the first part, when the latter is itself folded against the mast of the crane for transport. The folding section of this known embodiment is therefore not intended to fold and unfold the boom in a vertical plane.

On the basis of the above, the present invention provides an embodiment of a collapsible crane jib, of the type comprising an intermediate folding section, which aims to ensure the folding and unfolding of the jib in the vertical plane only, independently of the other stages of mounting the crane and avoiding the various drawbacks set out above.

For this purpose, a crane boom according to the invention comprises in known manner at least two main boom elements, including a boom foot and a boom tip, of relatively great length and at least one intermediate boom folding element, relatively short in length, interposed between two main jib elements, all the jib elements being hinged to each other around substantially horizontal axes at their lower members; this crane boom is essentially characterized in that the or each intermediate boom folding element is connected to a main boom element adjacent by a motorized member controlling the pivoting of this intermediate element around its axis of articulation with said main element, while the other main adjacent jib element is connected to the previous main element by a coupling assembly with at least three articulated members, the or one central member of which is also connected by articulation to a fixed point of the intermediate boom folding element, thus causing this other main boom element to pivot about its axis of articulation with the intermediate element.

According to a simple embodiment of the invention, applied to an arrow composed only of two main elements, namely an arrow foot and an arrow tip, and of a single intermediate arrow folding element interposed between the arrow and the arrowhead, the intermediate arrow folding element is connected to the arrowhead by the aforementioned motorized member, while the coupling assembly, with three articulated members, connects the arrowhead to the boom, the central element of this assembly also being connected by articulation to a fixed point of the intermediate boom folding element.

Thus, a motorized member directly controls the pivoting of the intermediate jib element relative to the jib foot, and the coupling assembly causes, simultaneously and as a consequence of the preceding movement, the pivoting of the jib tip relative to the intermediate element, so that in total the complete folding of the boom is obtained, the arrowhead being folded over the boom foot.

According to a preferred embodiment, the motorized member connecting the intermediate boom folding element to the boom foot is a double-acting hydraulic cylinder, the body of which is articulated at the end of the upper chord of the boom foot and the rod of which is articulated at the top of the intermediate boom folding element, or vice versa.

According to a particular embodiment, the intermediate boom folding element comprises two vertically offset vertices and connected by a double lateral triangulation to the lower members of said element, the first vertex, of height substantially greater than that of the other vertex, receiving the end of the rod or of the body of the jack, and the second vertex receiving the articulation of the central member of the coupling assembly connecting the arrowhead to the arrowhead.

According to another particularity, the boom foot comprises at its front end a double support, formed of two parts symmetrical with respect to the longitudinal median plane of the boom, of height substantially equal to that of the boom and the top of which carries an axis d articulation of one end of the first member of the coupling assembly.

According to another characteristic, the coupling assembly with three articulated members comprises a first single or multiple connecting rod, connecting the hinge pin carried by the aforementioned double support, disposed on the jib foot, to a hinge pin disposed at a first end of the central member, a bent lever with two branches forming said central member, the elbow receives the articulation on the second vertex of the intermediate boom folding element, and a second single or multiple connecting rod connecting an articulation axis disposed at the other end of the central member to a fixed articulation disposed at the rear end of the upper chord of the arrowhead.

Whatever the construction details of the boom folding device, this device is designed in such a way that, when the cylinder rod is retracted, the arrow tip is fully folded down on the boom foot, these two elements being then substantially parallel, and when the rod of the jack is fully extended, an alignment of the jib foot, of the intermediate element and of the jib tip is obtained, in particular to form a horizontal distributing jib, that is to say -to say a crane boom along which a load distribution carriage can move, rolling on the lower members of the three aligned boom elements. In addition, in the case of a horizontal distributing boom, the boom folding device according to the invention allows, during the folding of the boom, the recovery of the "slack" of the lifting cable and the distribution cable, whatever or the position of the arrowhead relative to the arrowhead.

Overall, a crane jib is thus produced, the folding and unfolding of which are carried out automatically and independently of the assembly phase of the crane on which the jib is mounted, and which can be fitted to any type of crane.

• Figure 1 montre, en vue de côté, une grue à montage automatisé en position de travail, équipée d'une flèche repliable conforme à la présente invention ;
• Figure 2 montre plus en détail et en vue de côté le dispositif de repliage de flèche, lorsque la flèche est dépliée ;
• Figure 3 est une vue en plan par dessus, partielle de cette flèche en position dépliée, en correspondance avec la figure 2 ;
• Figures 4, 5 et 6 sont des vues de côté similaires à la figure 2, illustrant plusieurs phases du repliage de la flèche.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended diagrammatic drawing representing, by way of nonlimiting example, an embodiment of this arrow with automated folding:

• Figure 1 shows, in side view, a crane with automatic assembly in the working position, equipped with a folding boom according to the present invention;
• Figure 2 shows in more detail and in side view the boom folding device, when the boom is unfolded;
• Figure 3 is a plan view from above, partial of this arrow in the unfolded position, in correspondence with Figure 2;
• Figures 4, 5 and 6 are side views similar to Figure 2, illustrating several phases of folding the boom.

The tower crane shown schematically in Figure 1 comprises, in known manner, a fixed or rolling base frame 1 supporting, by means of an orientation device 2, a rotating frame 3 which carries at the rear a counterweight 4 and at the front of which is articulated, around a horizontal axis 5, a foldable mast 6 composed of a base mast 7 and an upper mast 8 connected to one another by articulation on their rear face about a horizontal axis 9. This crane is provided with a distributing jib 10, foldable according to the invention, produced here in three successive elements designated respectively as jib foot 11, intermediate jib folding element 12 and tip jib 13, interconnected by joints 14,15 around horizontal axes arranged at their lower members (the concept of "lower" member being defined by reference to the arrow in the horizontal working position).

The upper mast 8 is connected to the rotating frame 3 by means of two straightening stays 16 arranged symmetrically on either side of the mast 6 and articulated respectively around a horizontal axis 17 located at the base of the upper mast 8 and around a horizontal axis 18 disposed at the rear part of the rotating chassis 3.

The boom 10 is articulated at the top of the mast 6 about a horizontal axis 19 and is held in position by a tie rod 20 connecting a fixed point 21 of the upper chord 22 of the boom foot 11 to the top 23 of a rigid punch 24 inclined towards the rear of the crane and articulated at the base of the jib foot 11 about a horizontal axis 25, said punch 24 being itself held in position by a rear retaining tie rod 26 connecting the top 23 of this punch rigid 24 at a fixed point 27 arranged at the rear part of the rotating chassis 3.

The crane is motorized for its mounting, that is to say for the raising of the mast 6, the lifting and unfolding of the boom 10. As shown in detail in FIG. 2, the boom 10 of triangular current section comprises a upper chord 22,28 respectively for the jib foot 11 and the jib tip 13, two lower chords 29,30,31, respectively for the jib foot 11, the intermediate jib folding member 12 and the jib tip 13, forming the base of the triangular section, and a set of triangulation bars 32 connecting the upper chord 22,28 and the lower members 29, 30, 31 therebetween to form a rigid triangular section.

The intermediate jib folding element 12, of relatively short length, compared to those of the jib foot 11 and the jib tip 13, comprises two vertically offset vertices 33, 34, joined to the lower members 30 by bars triangulation 35 and also substantially offset in height. The highest vertex 33, located opposite the arrowhead 11, is arranged in the median plane of the arrow 10, while the vertex 34 located opposite the arrowhead 13 is double and is arranged substantially at the plumb with the lower members 30 of said intermediate arrow folding element 12 and at the level of the upper member 28 of the arrow tip 13 when the elements of arrow 10 are aligned.

The boom folding device 10 according to the invention comprises a double-acting hydraulic cylinder 36 whose body 37 is articulated at 38 at the end of the upper member 22 of the boom foot 11, and whose rod 39 is articulated at the top 33 of the boom folding element 12, and a coupling assembly 40 produced in two parts symmetrical with respect to the longitudinal median plane of the boom 10, each consisting of a bent lever 41 and two double connecting rods 42 , 43 connecting the arrowhead 13 to the arrowhead 11 via the arrow folding element 12. The bent lever 41 has two branches 44,45, forming an obtuse angle oriented towards the inside of the arrow 10, and this lever 41 is articulated, at its elbow 46, at the top 34 of the intermediate boom folding element 12. The first double connecting rod 42 joins by two articulations 47, 48, respectively, the upper part of a support 49 fixed the front end of the jib foot 11, and the free end of the rear branch 44 of the bent lever 41. In correspondence with the arrangement of the connecting rods 42, the support 49 is a double support, formed by two parts symmetrical with respect to the longitudinal median plane of the crane; the height of the double support 49 is substantially equal to that of the arrow 10. The second double connecting rod 43 joins by two articulations 50, 51, respectively, the free end of the front branch 45 of the bent lever 41 and the rear end of the upper chord 28 of the arrowhead 13.

The elements 11, 12, 13 of the arrow 10 being in the aligned position as shown in FIGS. 2 and 3, the jack 36 has its rod 39 protruding entirely from the body 37 and substantially aligned with the upper chord 28 of the arrow tip 13 and with the part of the coupling assembly 40 formed by the second connecting rod 43 and by the front branch 45 of the bent lever 41, such that in service the longitudinal forces of the upper part of the arrow 10 are transmitted without significant discontinuity from the arrow tip 13 to the arrow foot 11.

From the unfolded position shown in Figures 2 and 3, the folding of the arrow 10 illustrated in Figures 4 to 6 is carried out as follows:

By actuating the double-acting hydraulic cylinder 36 in the re-entrant direction, the rod 39 sinks into the body 37 of said cylinder 36 and the distance between the joints 33, 38 carried respectively by the intermediate boom folding element 13 and by the jib foot 11 is shortened. As a result, the assembly made up of the two jib elements 12, 13 pivots around the articulation 14 of the jib 10. At the same time, the distance between the articulations 47, 51 carried respectively by the jib foot 11 and by the arrowhead 13 also shortens, causing the bent lever 41 to rotate around the articulation 34 of the intermediate arrow folding element 12 and consequently the pivoting of the arrowhead 13 around the articulation 15 of arrow 10.

It can thus be seen that simultaneously the intermediate arrow folding element 12 and the arrow tip 13 pivot respectively around the articulations 14 and 15 of the arrow 10, passing through the intermediate positions of FIGS. 4 and 5, until the arrowhead 13 is located entirely above the arrowhead 11.

In this final configuration shown in FIG. 6, it can be seen that the arrow tip 13 is inverted and occupies a position substantially parallel to the boom foot 11, while the intermediate arrow folding element 12 is tilted and occupies a position substantially perpendicular to the jib foot 11. Under these conditions, in order to obtain a minimum folded height for transporting the crane, the intermediate jib folding element 12 must have a length substantially equal to the sum of the heights of the jib foot 11 and of the arrowhead 13.

It goes without saying that, in order to unfold the arrow 10, from the folded position in FIG. 6, the reverse movements are caused, by controlling the jack 36 in the direction of the exit of its rod 39, so as to pass successively through the intermediate positions in Figures 5 and 4, before reaching the final unfolded position in Figures 2 and 3.

The actuator of the jack 36 can be controlled independently other mounting movements of the crane, the folding of the jib 10 can be carried out in any position of the jib 10 and of the crane equipped with this jib.

• par l'utilisation d'un organe motorisé à fonctions d'allongement et de raccourcissement autre qu'un vérin hydraulique à double effet, des moyens équivalents tels que vérins pneumatiques ou électriques, mécanisme à crémaillère, ou à roue tangente et vis sans fin, etc. étant naturellement utilisables ;
• par une modification du détail de l'ensemble d'accouplement, éventuellement en prévoyant plus de trois organes articulés ;
• par une modification du nombre des vérins, bielles, etc..., ces organes pouvant être simples, doubles ou multiples ;
• par une disposition inversée, en ce sens que le pied de flèche, et la pointe de flèche seraient échangés, par rapport à la disposition de l'organe motorisé et de l'ensemble d'accouplement ;
• par une application du même principe à des flèches de grues composées de plus de trois éléments, toujours avec des éléments de flèche principaux et des éléments intermédiaires de plus faible longueur, un dispositif de repliage tel que décrit ci-dessus étant associé à chaque élément intermédiaire ;
• par une adaptation du même principe de flèche repliable à d'autres types d'engins de levage, tels que grues à tour à mât télescopique, grues à tour à montage par éléments, grues à flèche relevable.

As is obvious, and as follows from the above, the invention is not limited to the only embodiment of this boom with automatic folding for crane which has been described above, by way of example ; on the contrary, it embraces all the variants of implementation and application based on the same principle. Thus, one would not depart from the scope of the invention:

• by the use of a motorized member with elongation and shortening functions other than a double-acting hydraulic cylinder, equivalent means such as pneumatic or electric cylinders, rack mechanism, or with tangent wheel and worm screw, etc. being naturally usable;
• by a modification of the detail of the coupling assembly, possibly by providing more than three articulated members;
• by a modification of the number of jacks, connecting rods, etc., these members being able to be single, double or multiple;
• by an inverted arrangement, in the sense that the jib foot and the arrowhead would be exchanged, with respect to the arrangement of the motorized member and the coupling assembly;
• by applying the same principle to crane jibs made up of more than three elements, always with main jib elements and shorter intermediate elements, a folding device as described above being associated with each intermediate element ;
• by adapting the same folding boom principle to other types of lifting equipment, such as tower cranes with telescopic mast, element-mounted tower cranes, cranes with lifting boom.

Claims (10)

1. Automatically folding crane jib, comprising at least two main jib sections, a jib base (11) and a jib outer end (13), which are relatively long, and at least one relatively short intermediate jib-folding section (12), interposed between two main jib sections, all the jib sections (11, 12, 13) being articulated on each other about substantially horizontal axes (14, 15) at the level of their bottom members (29, 30, 31), characterised in that the or each intermediate jib-folding section (12) is connected to an adjacent main jib section (11) by a motorised device (36) controlling the pivoting of this intermediate section (12) about its axis of articulation (14) on the said main section (11), while the other adjacent main jib section (13) is connected to the preceding main section (11) by a coupling assembly (40) with at least three articulated members (41, 42, 43), the middle one or ones of which (41) are also connected by articulation (at 34) to a fixed point on the intermediate jib-folding section (12), thus causing this other main jib section (13) to pivot about its axis of articulation (15) on the intermediate section (12).
2. Automatically folding crane jib according to Claim 1, characterised in that it comprises two main sections, namely a jib base (11) and a jib outer end (13), and a single intermediate jib-folding section (12) interposed between the jib base (11) and the jib outer end (13), and in that the intermediate jib-folding section (12) is connected to the jib base (11) by the above-mentioned motorised device (36), while the coupling assembly (40), with three articulated members (41, 42, 43), connects the jib outer end (13) to the jib base (11), the middle member (41) of this assembly (40) being also connected by articulation (at 34) to a fixed point on the intermediate jib-folding section (12).
3. Automatically folding crane jib according to Claim 2, characterised in that the motorised device connecting the intermediate jib-folding section (12) to the jib base (11) is a double-acting hydraulic jack (36), the body (37) of which is articulated (at 38) on the end of the top member (22) of the jib base (11) and the stem (39) of which is articulated on a vertex (33) of the intermediate jib-folding section (12), or vice versa.
4. Automatically folding crane jib according to Claim 3, characterised in that the intermediate jib-folding section (12) has two longitudinally offset vertices (33, 34) connected by a double lateral triangulation (35) to the bottom members (30) of the said section (12), the first vertex (33), with a height appreciably greater than that of the other vertex (34), receiving the end of the stem (39) or of the body (37) of the jack (36), and the second vertex (34) receiving the articulation of the middle member (41) of the coupling assembly (40) connecting the jib outer end (13) to the jib base (11).
5. Automatically folding crane jib according to any one of Claims 2 to 4, characterised in that the jib base (11) has at its front end a double support (49), composed of two parts which are symmetrical with respect to the longitudinal midplane of the jib (10), with a height substantially equal to that of the jib (10), and the vertex of which carries an axis of articulation (47) of one end of the first member (42) of the coupling assembly (40).
6. Automatically folding crane jib according to Claims 4 and 5 together, characterised in that the coupling assembly (40) with three articulated members comprises a first single or multiple link (42) connecting the articulation axis (47) carried by the aforesaid double support (49), disposed on the jib base (11), to an articulation axis (48) disposed at the end of one arm (44) of an angled lever (41) forming the middle member, a lever whose angle (46) receives the articulation on the second vertex (34) of the intermediate jib-folding section (12), and a second single or multiple link (43) connecting an articulation axis (50) disposed at the end of the other arm (45) of the middle member (41) to a fixed articulation (51) disposed at the rear end of the top member (28) of the jib outer end (13).
7. Automatically folding crane jib according to Claim 6, characterised in that the two arms (44, 45) of the angled lever (41) form an obtuse angle oriented towards the inside of the jib (10).
8. Automatically folding crane jib according to Claim 6 or 7, characterised in that the coupling assembly (40) is produced in two parts which are symmetrical with respect to the longitudinal mid-plane of the jib (10), each part of this assembly consisting of an angled lever (41) and two double links (42, 43).
9. Automatically folding crane jib according to any one of Claims 2 to 8, characterised in that the intermediate jib-folding section (12) has a length substantially equal to the sum of the heights of the jib base (11) and jib outer end (13).
10. Automatically folding crane jib according to any one of Claims 1 to 9, characterised in that it is articulated about a horizontal axis (19) at the top of a collapsible or telescopic mast (6) to form a self-erecting tower crane.

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