Punch structure for a crane that can be dismantled into two sub-assemblies

Abstract

Punch structure (3) for a crane, comprising: - a punch arm (4) having a foot (41) and a top (42); wherein the punch arm is decomposed into an upper punch arm half (47) to which at least one tie rod (5) is fixed, and a lower punch arm half (48) to which at least one reinforcing bar (7) is fixed, which are assembled by a removable intermediate mechanical linkage (49); such that the punch structure is demountable into two sub-assemblies, after removal of the removable intermediate mechanical linkage, which are an upper sub-assembly (31) comprising the upper punch arm half and at least one tie rod, and a lower sub-assembly (32) comprising the lower punch arm half and at least one reinforcing bar. Figure 5

Description

Title of the invention: Punch structure for a crane demountable in two sub-assemblies. Technical field

[0001] The invention relates to a punch structure for a crane.

[0002] It relates more particularly to a punch structure comprising a punch arm, and at least one tie rod and at least one reinforcing bar fixed on one side to the punch arm and intended to be fixed on the other side to a counter-jib of the crane.

[0003] The invention finds application in the field of cranes, and in particular modular cranes. Previous technique

[0004] In a known manner, a modular crane is composed of independent structural elements, also called frame elements, which are assembled to form a structure or framework, and in particular to form a mast also called a pylon (made up of several mast elements), a base on which the mast is mounted, as well as a rotating part which includes a jib at the top of the mast, a jib (made up of several jib elements) mounted hinged on the front of the jib, a counter-jib mounted on the rear of the jib, and a punch structure mounted on the counter-jib.

[0005] In the specific case of high-rise cranes, for example those exceeding 70 meters in height, it is necessary to use jib cranes fixed directly to the newly constructed building in order to dismantle the various components, and in particular the components of the rotating section. Indeed, mobile cranes, which are generally used for such dismantling, do not usually allow access to such heights.

[0006] However, the maximum payload of these jibs generally does not exceed 10 tonnes. Therefore, if the mass of a crane component exceeds 10 tonnes, dismantling that component becomes difficult. Consequently, for applications on high-reach cranes, it is common practice to use only components with a mass of less than 10 tonnes, which can limit the crane's capacity, particularly its load curve, maximum lifting capacity, and lifting capacity at the jib tip. Summary of the invention

[0007] The invention aims to solve, in whole or in part, the problem mentioned above, namely, to be able to offer a high-reach crane that is not limited in its capabilities due to the weight of its components, and in particular the weight of its punch structure.

[0008] To this end, the invention proposes a punch structure for a crane, comprising:

[0009] - a punch arm having a foot and a top;

[0010] - at least one tie rod comprising an upper tie rod end fixed to the apex of the punch arm; and

[0011] - at least one reinforcing bar comprising a fixed upper bar end on the punch arm, between the foot and the top.

[0012] This punch structure geometry is indeed suitable for high-reach cranes, notably through the use of at least one reinforcing bar (also called a buckling brace) whose function is to prevent buckling of the punch arm, particularly under heavy loads at the jib tip. In fact, to prevent excessive deformation under load, the punch arm must be supported approximately at its midpoint by one or more reinforcing bars, which thus divide the triangle formed by the punch arm and the tie rod(s) into two other triangles formed respectively by the punch arm and the reinforcing bar(s) (lower triangle) and by the tie rod(s) and the reinforcing bar(s) (upper triangle).

[0013] This punch structure is remarkable in that the punch arm is divided into an upper punch arm and a lower punch arm joined end-to-end by a removable intermediate mechanical link, the foot forming part of the lower punch arm and the top forming part of the upper punch arm; and in that the upper bar end of at least one reinforcing bar is fixed to the lower punch arm; so that the punch structure can be disassembled into two subassemblies, after disassembly of the removable intermediate mechanical link, which are an upper subassembly comprising the upper punch arm and at least one tie rod, and a lower subassembly comprising the lower punch arm and at least one reinforcing bar.

[0014] Thus, the design of the punch structure is based on a decomposition into two sub-assemblies of general triangular shape, such that the upper sub-assembly can be disassembled from the lower sub-assembly and the counter-hook in order to be carried separately, then the lower sub-assembly can be disassembled from the counter-hook in order to be carried separately in turn, before disassembly of the counter-hook which constitutes another element.

[0015] Indeed, by fixing the reinforcing bar(s) to the lower punch arm, therefore below the removable intermediate mechanical link, the lower sub-assembly (forming a triangular structure formed by the lower punch arm and The reinforcing bar(s) can remain in place on the counter-cam, while the upper sub-assembly can be disassembled.

[0016] In a particular embodiment, the punch structure includes at least one connecting element for a mechanical connection between at least one reinforcing bar and at least one tie rod, wherein at least one reinforcing bar has a lower bar end fixed on at least one connecting element, and at least one tie rod has a lower tie rod end which is assembled on at least one connecting element by at least one removable lower mechanical connection, so that the lower subassembly includes at least one connecting element, fixed to at least one reinforcing bar, after removal of at least one removable lower mechanical connection.

[0017] Thus, the tie rod(s) are detached from the connecting element (and are therefore separated from the reinforcing bar(s)) for the dismantling and winching of the upper sub-assembly, without the reinforcing bar(s) being detached from the counter-jib. Only subsequently, after detaching the upper sub-assembly, can the reinforcing bar(s) be detached from the counter-jib in order to detach and winch the lower sub-assembly in turn.

[0018] According to one feature, the at least one removable lower mechanical link is a pin link which includes at least one lower link pin ensuring a junction between the lower tie end of the at least one tie and the linking element.

[0019] It should be noted that the pin connection consists of a detachable assembly comprising a connecting pin (also called a spindle or axle) passing through two elements, such as a clevis and a tenon in order to have a clevis / tenon connection.

[0020] According to another feature, the lower bar end of at least one reinforcing bar is fixed securely to at least one connecting element, for example by welding.

[0021] In a particular embodiment, the at least one reinforcement bar includes a length adjustment arrangement for adjusting the length of the at least one reinforcement bar.

[0022] Such a length adjustment arrangement is advantageous because it avoids hyperstaticity in the assembly of the punch structure; adjusting the length of the reinforcing bar(s) provides an advantageous degree of freedom to facilitate assembly operations.

[0023] According to one possibility, the length adjustment arrangement includes a screw tensioner equipped with a nut with reverse threads, such as for example a lantern nut.

[0024] According to another possibility, the removable intermediate mechanical link is a pin link which includes at least one intermediate linking pin ensuring a junction between the upper punch arm and the lower punch arm.

[0025] According to another possibility, the upper punch half-arm includes a lower end opposite the top, the lower punch half-arm includes an upper end opposite the foot and at least one intermediate connecting pin provides a junction between this lower end and this upper end.

[0026] Advantageously, the upper bar end of at least one reinforcing bar is fixed to the upper end of the lower punch half-arm.

[0027] According to one possibility, the punch arm comprises two punch arm sections, which are a right-hand punch arm section and a left-hand punch arm section, where:

[0028] - the right-hand punch arm section is divided into an upper half-section of punch arm on the right and a lower half-section of punch arm on the right assembled end to end by the intermediate removable mechanical link;

[0029] - the left-hand punch arm section is divided into a half-section upper left-hand punch arm and lower left-hand punch arm half-section joined end to end by the removable intermediate mechanical link;

[0030] - the upper punch half-arm comprises the upper half-section of the arm punch on the right and the upper half-section of the punch arm on the left joined together;

[0031] - the lower punch half-arm comprises the lower half-section of the arm punch on the right and the lower half-section of punch arm on the left are joined together.

[0032] According to one variant, the at least one tie rod comprises two tie rods, one on the right and one on the left, fixed respectively on the upper half-section of the right-hand punch arm and the upper half-section of the left-hand punch arm.

[0033] According to one feature, at least one reinforcement bar comprises two reinforcement bars, which are a right-hand reinforcement bar and a left-hand reinforcement bar fixed respectively on the lower half-section of the right-hand punch arm and the lower half-section of the left-hand punch arm.

[0034] In an advantageous embodiment, the reinforcement bar on the right and the reinforcement bar on the left each include the length adjustment arrangement.

[0035] Thus the length of each of the two reinforcement bars can be adjusted independently.

[0036] According to another feature, the at least one connecting element comprises two connecting elements which are a connecting element on the right and a connecting element on the left, where the reinforcing bar on the right is fixed on the connecting element on the right and the reinforcing bar on the left is fixed on the connecting element on the left.

[0037] According to one possibility, the at least one removable lower mechanical linkage comprises a removable lower mechanical linkage on the right and a removable lower mechanical linkage on the left which respectively connect the right tie rod to the right connecting element and the left tie rod to the left connecting element.

[0038] In a particular embodiment, the upper sub-assembly has a first mass which is less than 10 Tonnes, the lower sub-assembly has a second mass which is less than 10 Tonnes and the punch structure has a total mass which corresponds to the sum of the first mass and the second mass and which is greater than 10 Tonnes.

[0039] The invention also relates to a crane comprising a rotating part at the top of a mast, said rotating part comprising a jib holder, a jib articulated on the jib holder, a counter jib mounted on the jib holder and a punch structure as described above, in which the foot of the punch arm is assembled on the counter jib by a first removable mechanical linkage, at least one tie rod and at least one reinforcing bar are assembled on the counter jib by a second removable mechanical linkage.

[0040] According to one feature, at least one connecting element is assembled on the counter-arrow by the second removable mechanical link. Brief description of the drawings

[0041] Other features and advantages of the present invention will become apparent from the following detailed description of a non-limiting example of implementation, made with reference to the accompanying figures in which:

[0042] [Fig-1] is a schematic side and partial view of a rotating part of a crane, in which the jib carrier, the jib, the counter jib and the punch structure are visible;

[0043] [Fig.2] is a schematic side view of the punch structure of [Fig.1] during handling by slinging, with a zoom on a rocker leg in rocker position;

[0044] [Fig.3] is a schematic side view of the punch structure of [Fig.1] in situ on the counter-jib, where at least one rocker leg is in rest position, and with a first zoom on a connecting element between a tie rod, a reinforcing bar and the counter-jib, and a second zoom on a removable intermediate connection between an upper half-puncher and a lower half-puncher;

[0045] [Fig.4] is a schematic, partial perspective view of the punch structure of the [Fig.2] in position on the counter-arrow;

[0046] [Fig. 5] is a schematic view of the punch structure of Figures 1 to 3 once disassembled into two sub-assemblies;

[0047] [Fig.6] is a schematic perspective view zoomed in on the connecting element between the tie rod, the reinforcement bar and the counter-camber, and on the length adjustment arrangement of the reinforcement bar;

[0048] [Fig.7] is a schematic side and partial view of the punch structure of the Figures 1 to 3, with a zoom on the connecting element between the tie rod, the reinforcement bar and the counter-curve, and on the length adjustment arrangement of the reinforcement bar.

[0049] [Detailed description of an embodiment of the invention]

[0050] With reference to [Fig. 1], a crane 1, here a luffing jib crane with modular assembly, comprises a base chassis (not shown), fixed or mobile on the ground, above which rises a mast (not shown) which extends along a vertical axis Z and which has a top on which is mounted, by means of a slewing device (not shown), a rotating part 2 orientable around the vertical axis Z.

[0051] This rotating part 2 includes a boom carrier 20 at the top of the mast, a boom 21 (made up of several boom elements) mounted hinged on the front of the boom carrier 20, a counter boom 22 mounted on the rear of the boom carrier 20, and a punch structure 3 mounted on the counter boom 22.

[0052] The boom 21 is mounted movable in rotation around a horizontal axis on the boom holder 20 so that the boom 21 can be raised and lowered.

[0053] The counter-jib 22 is fixedly mounted on the boom support 20 so as to be rotationally fixed to the latter. The counter-jib 22 includes a platform for carrying equipment which includes, in particular, a lifting winch 10 connected to the boom 21 for raising / lowering the boom 21 and a lifting winch 11 connected to a lifting hook (not shown) for lifting loads. The counter-jib 22 also carries counterweights 12.

[0054] More specifically, the lifting winch 10 has a drum, around which is wound a lifting cable which passes over a pulley 13 disposed at the top of the punch structure 3, and which also passes over the pulleys of a lifting block 14 (illustrated in [Fig.1]), located at the top 42 of the punch structure 3. The lifting block 14 is connected, by a line of tie rods (not illustrated), to the boom 21.

[0055] The lifting winch 11 has a drum on which is wound a lifting cable, which passes through the punch structure 3, passes over at least one pulley (not shown) arranged on the boom 21, then is directed towards the tip of the boom 21 and extends to the lifting hook, with or without a pulley block; the loads to be lifted being suspended from the lifting hook when using the crane 1.

[0056] The counter-jib 22 can be mechanically coupled to the jib carrier 20 by means of a reinforcing beam 23 (visible on [Fig.4]) extending between the underside of the counter-jib 22 and the jib carrier 20.

[0057] The punch structure 3 comprises a punch arm 4 extending longitudinally along a punch axis 40 and having a foot 41 and a tip 42 (this tip 42 forming the tip of the punch structure 3). In operation, this punch arm 4 extends obliquely upwards and backwards. The punch axis 40 is thus inclined backwards relative to the vertical axis Z at a punch angle of between 10 and 50 degrees.

[0058] The foot 41 of the punch arm 4 is assembled on the counter-arrow 22 by a first removable mechanical link 43 which may be a pin link; a pin link consisting of a removable assembly comprising a connecting pin (also called a pin or axis) passing through two elements, such as for example a clevis and a tenon in order to have a clevis / tenon link.

[0059] The top 42 of the punch arm 4 is equipped with a hooking member 420 for hooking a sling, such as for example a hooking ring or slinging ring.

[0060] The punch structure 3 also includes at least one tie rod 5 having an upper tie rod end 51 fixed to the top 42 of the punch arm 4 and a lower tie rod end 52 assembled to the counter-jib 22 by a second removable mechanical linkage 60, which may be a pin linkage. Thus, in operation, the punch arm 4 is held by the counter-jib 22 by means of the tie rod(s) 5.

[0061] The punch structure 3 includes at least one reinforcing bar 7 having an upper bar end 71 fixed on the punch arm 4, between the foot 41 and the top 42, and a lower bar end 72 assembled on the counter-jib 22.

[0062] The punch structure 3 includes at least one connecting element 6 for a mechanical connection between at least one reinforcing bar 7 and at least one tie rod 5. This at least one connecting element 6 is intended to be assembled on the counter-jib 22 by the second removable mechanical connection 60 which, as a reminder, can be a pin connection.

[0063] The lower tie end 52 of at least one tie 5 is assembled on the connecting element 6 by at least one removable lower mechanical connection 53 which may be a pin connection comprising a lower connecting pin 530.

[0064] The lower bar end 72 of at least one reinforcing bar 7 is fixed to the connecting element 6. The lower bar end 72 of at least one reinforcing bar 7 can be fixed securely to the connecting element, for example by welding.

[0065] Thus, at least one tie rod 5 and at least one reinforcing bar 7 are assembled on the counter-arrow 22 by the second removable mechanical link 60 of at least one connecting element 6.

[0066] According to one possibility, the at least one reinforcing bar 7 has a length adjustment arrangement 73 for adjusting the length of the at least one reinforcing bar 7, as seen in [Fig.4] and [Fig.5], which is for example positioned at the lower bar end 72.

[0067] In the illustrated example visible in Figures 6 and 7, this length adjustment arrangement 73 includes a screw tensioner equipped with a reverse threaded nut 74, such as for example a lantern nut.

[0068] Such a length adjustment arrangement 73 is advantageous because it avoids hyperstaticity in the assembly of the punch structure 3; the adjustment of the length of the reinforcing bar(s) 7 provides an advantageous degree of freedom to facilitate assembly operations.

[0069] As seen in [Fig.4]: - the punch arm 4 comprises two punch arm sections 45, 46, which are a right-hand punch arm section 45 and a left-hand punch arm section 46 which extend parallel along the punch axis 40 and which are joined by means of the foot 41, the top 42 and intermediate spacers 430; - at least one tie rod 5 comprises two tie rods 5, which are a right tie rod and a left tie rod extending parallel, where the right tie rod is fixed to the top 42 of the punch arm 4 on the right side of the punch arm section 45, and the left tie rod is fixed to the top 42 of the punch arm 4 on the left side of the punch arm section 46; - at least one reinforcing bar 7 comprises two reinforcing bars 7, which are a reinforcing bar 7 on the right and a reinforcing bar 7 on the left extending parallel to each other, where the reinforcing bar 7 on the right is fixed to the right-hand punch arm section 45 and the reinforcing bar 7 on the left is fixed to the left-hand punch arm section 46; and - at least one connecting element 6 comprises two connecting elements 6 which are a connecting element 6 on the right and a connecting element 6 on the left arranged side by side on two separate beams 220 of the counter-camber 22, where the connecting element 6 on the right is assembled with the tie 5 on the right and the reinforcing bar 7 on the right and the connecting element 6 on the left is assembled with the tie 5 on the left and the reinforcing bar 5 on the left.

[0070] Thus, the lower tie rod end 52 of the tie rod 5 on the right is assembled onto the connecting element 6 on the right by a removable lower mechanical link 53 on the right, and the lower tie rod end 52 of the tie rod 5 on the left is assembled onto the connecting element 6 on the left by a lower removable mechanical link 53 on the left. In other words, the at least one lower removable mechanical link 53 comprises a lower removable mechanical link 53 on the right and a lower removable mechanical link 53 on the left which respectively connect the tie rod 5 on the right to the connecting element 6 on the right and the tie rod 5 on the left to the connecting element 6 on the left.

[0071] Furthermore, the lower bar end 72 of the reinforcing bar 7 on the right is fixed on the connecting element 6 on the right, and the lower bar end 72 of the reinforcing bar 7 on the left is fixed on the connecting element 6 on the left.

[0072] In the illustrated example, the reinforcement bar 7 on the right and the reinforcement bar 7 on the left each have the length adjustment arrangement 73.

[0073] According to one feature and as seen in Figures 3 and 5, the punch arm 4 is decomposed into an upper punch arm 47 and a lower punch arm 48 assembled end to end by a removable intermediate mechanical link 49, the foot 41 being part of the lower punch arm 48 and the top 42 being part of the upper punch arm 47.

[0074] This removable intermediate mechanical link 49 can be a pin link which includes at least one intermediate connecting pin 490 ensuring a junction between the upper punch half-arm 47 and the lower punch half-arm 48. In the illustrated example, the removable intermediate mechanical link 49 includes two intermediate connecting pins 490.

[0075] The upper punch half-arm 47 includes a lower end 470 opposite the top 42, the lower punch half-arm 48 includes an upper end 480 opposite the foot 41 and at least one intermediate connecting pin 490 provides a junction between this lower end 470 and this upper end 480.

[0076] Furthermore, the upper bar end 71 of at least one reinforcing bar 7 is fixed to the lower punch arm 48. According to one possibility, the upper bar end 71 of at least one reinforcing bar 7 is fixed to the upper end 480 of the lower punch arm 48, as seen in [Fig.3].

[0077] As a reminder, in the illustrated example, the punch arm 4 comprises two punch arm sections 45, 46, which are a right-hand punch arm section 45 and a left-hand punch arm section 46, such that: - the right-hand punch arm section 46 is divided into an upper half-section of the right-hand punch arm and a lower half-section of the right-hand punch arm assembled end to end by the removable intermediate mechanical link 49; - the left-hand punch arm section 46 is divided into an upper half of the left-hand punch arm section and a lower half of the arm section punch on the left assembled end to end by the removable intermediate mechanical link 49; - the upper punch arm half 47 comprises the upper punch arm half section on the right and the upper punch arm half section on the left joined together; - the lower punch arm half 48 comprises the lower punch arm half section on the right and the lower punch arm half section on the left joined together.

[0078] Thus, the tie rod 5 on the right and the tie rod 5 on the left are fixed respectively on the upper half-section of the punch arm on the right and the upper half-section of the punch arm on the left, and the reinforcing bar 7 on the right and the reinforcing bar 7 on the left are fixed respectively on the lower half-section of the punch arm on the right and the lower half-section of the punch arm on the left.

[0079] Thus, and as can be seen in [Fig. 5], the punch structure 3 can be disassembled into two sub-assemblies, after disassembly of the removable intermediate mechanical link 49 and at least one removable lower mechanical link 53, which are: - an upper subassembly 31 comprising the upper punch half-arm 47 and at least one tie rod 5 (or both tie rods 7 in the illustrated example); and - a lower subassembly 32 comprising the lower punch half-arm 48 and at least one reinforcing bar 7 (or both reinforcing bars 7 in the illustrated example) and at least one connecting element 6 (or both connecting elements 6 in the illustrated example) which remains attached to at least one reinforcing bar 7.

[0080] Thus, the design of the punch structure 3 is based on a decomposition into two sub-assemblies 31, 32 of general triangular shape, such that the upper sub-assembly 31 can be disassembled from the lower sub-assembly 32 and the counter-hook 22 in order to be carried separately, then the lower sub-assembly 32 can be disassembled from the counter-hook 22 in order to be carried separately in turn, before disassembly of the counter-hook 22 which constitutes another element.

[0081] According to one possibility, the upper sub-assembly 31 has a first mass which is less than 10 Tonnes, the lower sub-assembly 32 has a second mass which is less than 10 Tonnes and the punch structure 3 has a total mass which corresponds to the sum of the first mass and the second mass and which is greater than 10 Tonnes.

[0082] The punch structure 3 comprises at least one rocker leg 8 mounted on the foot 41 of the punch arm 4 opposite the tie rod 5 (i.e., on the rear side or the side of the counter-jib 22) and having a lower end 80 intended to form a rocker support for the punch structure 3 because, in a rocker position (illustrated on the [Fig.2]), this at least one rocker leg 8 is deployed to have its lower end 80 below the foot 41 of the punch arm 4 when a theoretical equilibrium axis W is disposed vertically (i.e. the theoretical equilibrium axis W extends parallel to the vertical axis Z); this theoretical equilibrium axis W being an axis passing through the hooking member 420 and through the center of gravity G of the punch structure 3.

[0083] As can be seen in [Fig.2], in the tilting position of the rocker leg 8, the theoretical equilibrium axis W is positioned between the lower end 80 of at least one rocker leg 8 and the punch axis 40 when this theoretical equilibrium axis W is arranged vertically; in other words, the lower end 80 of at least one rocker leg 8 is behind (counter-swing side) the theoretical equilibrium axis W, thus promoting the balancing of the punch structure 3 to prevent it from falling.

[0084] This at least one rocker leg 8 is movable or retractable in a rest position (illustrated in Figures 1, 3, 4 and 5), in which the at least one rocker leg 8 is retracted to have its lower end 80 above the foot 41 of the punch arm 4 when the theoretical equilibrium axis W is arranged vertically.

[0085] Thus, this at least one rocker leg 8 is mounted movably on a support 81 between its rocker position and its rest position; this support 81 being assembled on the foot 41 of the punch arm 4 by a mechanical linkage 82, and for example by a removable mechanical linkage such as a pin linkage which includes at least one connecting pin 83 ensuring a junction between the support 81 and the foot 41 of the punch arm 4.

[0086] A locking mechanism mounted on the support 81 is also provided for locking at least one rocker leg 8 in the rocker position and in the rest position. This locking mechanism may include a locking pin that passes through the support 81 to lock the rocker leg 8 in the rocker position and in the rest position.

[0087] As seen in [Fig.4], the at least one rocker leg 8 comprises two rocker legs 8, which are a rocker leg 8 on the right attached to the right punch arm section 45 and a rocker leg 8 on the left attached to the left punch arm section 46.

[0088] In position on the crane 1, that is, once the punch structure 3 is mounted and assembled on the counter-jib 22, at least one rocker leg 8 is in its rest position. At least one rocker leg 8 is even placed in its rest position during assembly on the counter-jib 22, so as not to come interfere with or bump against the counter-arrow 22, in particular when assembling the foot 41 of the punch arm 4 onto the counter-arrow 22.

[0089] On the other hand, and as can be seen in [Fig.2], during the handling operations by slinging of the punch structure 3, in particular on the ground when the punch structure 3 is lifted to straighten it or conversely when the punch structure 3 is lowered to lie down, at least one rocker leg 8 is in its rocker position, so that its lower end 80 forms a rocker support for the punch structure 3 on the ground (see the zoom of [Fig.2]) when the punch arm 4 passes from a horizontal lying position to a vertical raised position, or vice versa.

Claims

Demands

1. Punch structure (3) for a crane (1), comprising: - a punch arm (4) having a foot (41) and a top (42); - at least one tie rod (5) having an upper tie rod end (51) fixed to the top (42) of the punch arm (4); and - at least one reinforcing bar (7) having an upper bar end (71) fixed to the punch arm (4), between the foot (41) and the top (42); said punch structure (3) being characterized in that the punch arm (4) is decomposed into an upper punch arm half (47) and a lower punch arm half (48) joined end to end by a removable intermediate mechanical link (49), the foot (41) forming part of the lower punch arm half (48) and the top (42) forming part of the upper punch arm half (47); and in that the upper bar end (71) of at least one reinforcing bar (7) is fixed to the lower punch half-arm (48);so that the punch structure (3) is detachable into two sub-assemblies (31, 32), after dismantling of the intermediate detachable mechanical linkage (49), which are an upper sub-assembly (31) comprising the upper punch half-arm (47) and at least one tie rod (5), and a lower sub-assembly (32) comprising the lower punch half-arm (48) and at least one reinforcing bar (7).

2. Punch structure (3) according to claim 1, comprising at least one connecting element (6) for a mechanical connection between at least one reinforcing bar (7) and at least one tie rod (5), wherein at least one reinforcing bar (7) has a lower bar end (72) fixed to at least one connecting element (6), and at least one tie rod (5) has a lower tie rod end (52) which is assembled to at least one connecting element (6) by at least one removable lower mechanical connection (53), so that the lower subassembly (32) comprises at least one connecting element (6), fixed to at least one reinforcing bar (7), after removal of at least one removable lower mechanical connection (53).

3. Punch structure (3) according to claim 2, wherein at least one removable lower mechanical linkage (53) is a pin connection which includes at least one lower connecting pin (530) providing a connection between the lower tie end (52) of at least one tie (5) and the connecting element (6).

4. Punch structure (3) according to claim 2 or 3, wherein the lower bar end (72) of at least one reinforcing bar (7) is fixed securely to at least one connecting element (6), for example by welding.

5. Punch structure (3) according to any one of claims 1 to 4, wherein at least one reinforcing bar (7) has a length adjustment arrangement (73) for adjusting the length of at least one reinforcing bar (7).

6. Punch structure (3) according to claim 5, wherein the length adjustment arrangement (73) comprises a screw tensioner equipped with a reverse-threaded nut (74), such as for example a lantern nut.

7. Punch structure (3) according to any one of the preceding claims, wherein the removable intermediate mechanical link (49) is a pin link which includes at least one intermediate linking pin (490) providing a junction between the upper punch half-arm (47) and the lower punch half-arm (48).

8. Punch structure (3) according to claim 7, wherein the upper punch half-arm (47) comprises a lower end (470) opposite the top (42), the lower punch half-arm (48) comprises an upper end (480) opposite the foot (41) and at least one intermediate connecting pin (490) provides a junction between this lower end (470) and this upper end (480).

9. Punch structure (3) according to claim 8, wherein the upper bar end (71) of at least one reinforcing bar (7) is fixed to the upper end (480) of the lower punch half-arm (48).

10. Punch structure (3) according to any one of the preceding claims, wherein the punch arm (4) comprises two punch arm sections (45, 46), which are a right-hand punch arm section (45) and a left-hand punch arm section (46), where: - the right-hand punch arm section (45) is divided into an upper right-hand punch arm section and a lower half- - lower section of punch arm on the right assembled end to end by the removable intermediate mechanical link (49); - the section of punch arm on the left (46) is divided into an upper half-section of punch arm on the left and a lower half-section of punch arm on the left assembled end to end by the removable intermediate mechanical link (49); - the upper half-section of punch arm (47) comprises the upper half-section of punch arm on the right and the upper half-section of punch arm on the left joined together; - the lower half-section of punch arm (48) comprises the lower half-section of punch arm on the right and the lower half-section of punch arm on the left joined together.

11. Punch structure (3) according to claim 10, wherein the at least one tie rod (5) comprises two tie rods (5) which are a tie rod (5) on the right and a tie rod (5) on the left fixed respectively on the upper half-section of the punch arm on the right and the upper half-section of the punch arm on the left.

12. Punch structure (3) according to claim 10 or 11, wherein at least one reinforcing bar (7) comprises two reinforcing bars (7) which are a right-hand reinforcing bar (7) and a left-hand reinforcing bar (7) fixed respectively on the lower half-section of the right-hand punch arm and the lower half-section of the left-hand punch arm.

13. Punch structure (3) according to claims 4 and 12, wherein the right-hand reinforcing bar (7) and the left-hand reinforcing bar (7) each have the length adjustment arrangement (73).

14. Punch structure (3) according to claims 2 and 12, wherein at least one connecting element (6) comprises two connecting elements (6) which are a connecting element (6) on the right and a connecting element (6) on the left, where the reinforcing bar (7) on the right is fixed to the connecting element (6) on the right and the reinforcing bar (7) on the left is fixed to the connecting element (6) on the left.

15. Punch structure (3) according to claims 2, 11 and 14, wherein at least one removable lower mechanical linkage (53) comprises a removable lower mechanical linkage (53) on the right and a removable lower mechanical linkage (53) on the left which respectively connect the tie rod (5) on the right to the connecting element (6) on the right and the tie rod (5) on the left to the connecting element (6) on the left.

16. Punch structure (3) according to any one of the preceding claims, wherein the upper subassembly (31) has a first mass which is less than 10 Tonnes, the lower subassembly (32) has a second mass which is less than 10 Tonnes and the punch structure (3) has a total mass which corresponds to the sum of the first mass and the second mass and which is greater than 10 Tonnes.

17. Crane (1) comprising a rotating part (2) at the top of a mast, said rotating part (2) comprising a jib holder (20), a jib (21) articulated on the jib holder (20), a counter jib (22) mounted on the jib holder (20) and a punch structure (3) according to any one of the preceding claims, wherein the foot (41) of the punch arm (4) is assembled on the counter jib (22) by a first removable mechanical linkage (43), at least one tie rod (5) and at least one reinforcing bar (7) are assembled on the counter jib (22) by a second removable mechanical linkage (60).

18. Crane (1) according to claim 17, wherein the punch structure (3) conforms to claim 2 and at least one connecting element (6) is assembled on the counter boom (22) by the second removable mechanical linkage (60).

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