Tower crane and linking joint for tower crane

Abstract

The tower crane (1) comprises: a plurality of tower sections (2, 3); and at least one linking joint (8) comprising: at least one stud bolt element (9); at least one upper spacer element (12) provided with at least one upper hole (13) in which the stud bolt element (9) is insertable; at least one lower spacer element (14) provided with at least one lower hole (15) in which the stud bolt element (9) is insertable; at least one upper nut element (16); at least one lower nut element (17); fastening means (18) of the lower spacer element (14) to an upper attachment portion (7) of a tower section (2, 3); and at least one supporting plate (19) associable with the lower spacer element (14) and adapted to support the lower nut element (17) in a position of alignment with the lower hole (15).

Description

[0001] TOWER CRANE AND LINKING JOINT FOR TOWER CRANE

[0002] Technical Field

[0003] The present invention relates to a tower crane and a related linking joint for tower crane.

[0004] Background Art

[0005] Tower cranes are known to substantially consist of a ground-supporting bedplate, a substantially vertical tower mounted on the bedplate and a substantially horizontal or tilting boom, which is mounted at the top of the tower and carries a sliding carriage and / or a set of pulleys and ropes for lifting loads.

[0006] The tower consists of a plurality of tower sections, which are associated with each other in succession one on top of the other; an example of a tower built according to the prior art is shown in Figure 1 wherein, for simplicity’s sake, only a lower section A and an upper section B are visible.

[0007] The tower sections A, B comprise a base C, where a plurality of lower attachment portions D is obtained, and a top E, where a plurality of upper attachment portions F is obtained.

[0008] The lower attachment portions D of the upper section B are joined to the upper attachment portions F of the lower section A by means of a plurality of linking joints G, each of which comprises: a pair of stud bolt elements H; an upper spacer element I, which can be placed on top of the lower attachment portion D of the upper section B and is provided with a pair of upper holes into which the stud bolt elements H can be inserted; a lower spacer element L which can be placed under the upper attachment portion F of the lower section A and is provided with a pair of lower holes into which the stud bolt elements H can be inserted; a pair of upper nuts M and a pair of lower nuts N screwable to the opposite ends of the stud bolt elements H.

[0009] For tower erection, in actual facts, the upper section B is lowered from above the lower section A with the upper spacer elements I, the stud bolt elements H and the upper nuts M already pre-assembled, meaning that the upper spacer elements I are placed on top of the lower attachment portions D of the upper section B, the stud bolt elements H are inserted within them and the upper nuts M are screwed to the top of the stud bolt elements H.

[0010] In this configuration, the lower ends of the stud bolt elements H protrude below the lower attachment portions D of the upper section B as the latter is raised and have the ability to couple to the upper attachment portions F of the lower section A when the upper section B is lowered and rested on the lower section A.

[0011] At this point, the lower spacer elements L and the lower nuts N are manually placed in position by the operators in charge of assembly operations, who also take care of the proper tightening of the stud bolt elements H and of the corresponding nuts M, N.

[0012] These tower cranes and these linking joints do have some related drawbacks.

[0013] The assembly phase of the tower sections A, B, in fact, involves serious safety issues for the operators, since the lower spacer elements L and the lower nuts N have to be inconveniently carried overhead and handled manually by the operators and, taking into account their non-negligible weight, this operation is not easy at all.

[0014] In this regard, it is noted that as long as the nuts are not tightened properly on the stud bolt elements, unwanted and dangerous falling of objects from the tower under construction can occur, which can greatly endanger the lives of people and the integrity of the equipment and materials at the base of the crane.

[0015] In addition to this, the risk of very heavy objects falling can occur even after the nuts have been properly tightened, as in the case where one of the stud bolt elements breaks in half during normal crane operation; in this case, in fact, the upper portion of the stud bolt element H that broke remains hanging on the crane due to the fact that its upper nut rests on the upper spacer element, but the lower portion of the stud bolt element H that broke and its lower nut N fall into the void. It is easy to appreciate, moreover, that the difficulties in assembling the linking joints of known type result in a significant lengthening of the construction work time and, consequently, a significant increase in site construction costs, which, inevitably, are passed on to the overall expense of the construction activities for which the crane is intended.

[0016] Description of the Invention

[0017] The main aim of the present invention is to devise a tower crane and a linking joint for tower crane which allow the tower sections of the crane to be assembled with great ease, under conditions of great safety for the operators and in a very quick and short time.

[0018] A further object of the present invention is to devise a tower crane and a linking joint for tower crane which allow the site and construction costs of the construction work wherein the crane is used to be reduced.

[0019] Another object of the present invention is to devise a tower crane and a linking joint for tower crane which allow the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as affordable solution.

[0020] The aforementioned objects are achieved by this tower crane having the characteristics of claim 1.

[0021] The aforementioned objects are also achieved by this linking joint for tower crane having the characteristics of claim 10.

[0022] Brief Description of the Drawings

[0023] Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive embodiment of a tower crane, illustrated by way of an indicative, yet non-limiting example in the attached tables of drawings wherein:

[0024] Figure 1 is a partial axonometric view of a tower crane built according to the state-of-the-art teachings;

[0025] Figure 2 is a partial axonometric view of the tower crane in accordance with a first embodiment of the invention;

[0026] Figure 3 is a partial axonometric view of the tower crane in Figure 2 in the assembly phase;

[0027] Figure 4 is an exploded view of a detail of the tower crane in Figure 2;

[0028] Figure 5 is an axonometric view of a detail of the linking joint according to the invention; Figure 6 is a side view, in partial transparency, of the detail of the tower crane in Figure 4 under a condition of breakage of one of the stud bolt elements;

[0029] Figure 7 is a partial axonometric view of the tower crane in accordance with a second embodiment of the invention.

[0030] Embodiments of the Invention

[0031] With particular reference to the embodiment shown in Figures 2 through 6, reference numeral 1 globally denotes a tower crane.

[0032] The tower crane 1 comprises a plurality of tower sections 2, 3 which can be placed on top of each other to define a tower.

[0033] For representation’s sake, Figures 2 and 3 partly show the tower crane 1, i.e., with only two tower sections 2, 3; it is however easy to appreciate that a varying number of tower sections 2, 3 can be used for the tower erection of the tower crane 1 until the desired height of the crane is achieved.

[0034] The tower sections 2, 3 shown in the figures are substantially identical to each other and consist of a plurality of bars and tie rods made of steel and welded together; in order to distinguish one tower section 2, 3 from the other in the remainder of this disclosure, they may also be referred to as lower tower section 2 and upper tower section 3, where the adjectives “lower” and “upper” are to be meant with respect to their normal position of use, i.e., the assembly configuration of the tower crane 1 wherein the upper tower section 3 is placed above the lower tower section 2.

[0035] In addition, the adjectives “lower” and “upper”, as well as the related terms such as “inferiorly”, “superiorly”, “above”, “below”, “base”, “top” etc., may be used with respect not only to the tower sections 2, 3 but also to any other component of the tower crane 1 and always with reference to the configuration of use and assembly of the crane itself.

[0036] The tower sections 2, 3 are provided with a base 4 having at least one lower attachment portion 5, and with a top 6, having at least one upper attachment portion 7.

[0037] Conveniently, the base 4 and the top 6 of the tower sections 2, 3 have a square plan conformation and have lower attachment portions 5 and upper attachment portions 7 located at all four comers.

[0038] The lower attachment portions 5 and the upper attachment portions 7, in actual facts, consist of plates welded together to define seats intended to be placed substantially matching each other, i.e., with the lower attachment portions 5 of the upper tower section 3 arranged where the upper attachment portions 7 of the lower tower section 2 are located.

[0039] The tower crane 1 also comprises at least one linking joint 8 configured to join and stably connect the attachment portions 5, 7, i.e., a lower attachment portion 5 of the upper tower section 3 to an upper attachment portion 7 of the lower tower section 2.

[0040] Conveniently, given that the tower crane 1 comprises a plurality of attachment portions 5, 7, then a plurality of linking joints 8 is also provided; for exposition’s sake, in the remainder of this disclosure we will describe in detail and refer to only one linking joint 8, except when explicitly stated otherwise.

[0041] The linking joint 8 comprises:

[0042] - at least one stud bolt element 9 provided with an upper threaded end 10 and with a lower threaded end 11; at least one upper spacer element 12, which can be placed on top of the lower attachment portion 5 of the upper tower section 3 and provided with at least one upper hole 13 in which the stud bolt element 9 is insertable; at least one lower spacer element 14, which can be placed below the upper attachment portion 7 of the lower tower section 2 and provided with at least one lower hole 15 in which the stud bolt element 9 is insertable; at least one upper nut element 16 screwable onto the upper threaded end 10; at least one lower nut element 17 screwable onto the lower threaded end 11; fastening means 18 configured to fasten the lower spacer element 14 to the upper attachment portion 7 of the lower tower section 2; and at least one supporting plate 19 associable with the lower spacer element 14 and adapted to support the lower nut element 17 in a position of alignment with the lower hole 15.

[0043] Advantageously, the stud bolt element 9 consists, in actual facts, of a cylindrical pin of adequate diameter to withstand the large forces that, in use, burden the tower crane 1.

[0044] The spacer elements 12, 14, on the other hand, consist of blocks of substantially rectangular conformation intended to be placed on opposite sides from the attachment portions 5, 7 to receive the tightening force exerted by the nut elements 16, 17 and to distribute it evenly over the attachment portions themselves.

[0045] In fact, when the nut elements are screwed onto the two threaded ends 10, 11 of the stud bolt element 9, the spacer elements 12, 14 are squeezed and pushed towards each other from opposite sides to the attachment portions 5, 7, thus creating a sandwich consisting of, on the outside, the nut elements 16, 17 and the spacer elements 12, 14 and, on the inside, the attachment portions 5, 7.

[0046] Conveniently, the fastening means 18 comprise: at least one through opening 20 made in the lower spacer element 14; and at least one fastening screw 21 insertable in the through opening 20 and screwable in the upper attachment portion 7 of the lower tower section 2.

[0047] For this purpose, it is noticed that the upper attachment portion 7 of the lower tower section 2 has a lower surface 7a which is provided with a threaded hole 7b into which the fastening screw 21 can be screwed.

[0048] In actual facts, thanks to the fastening means 18, the lower spacer element 14 can be associated with the lower tower section 2 while the latter is still on the ground and can be lifted to the desired height together with the lower tower section 2, thus allowing the problems and risks related to the positioning of the lower spacer element 14 that plague the prior art to be fixed.

[0049] Advantageously, the lower nut element 17 comprises at least one anti -rotational portion 17a having an outer shape with a substantially square cross-section.

[0050] The square shape of the anti -rotational portion 17a allows the lower nut element 17 not to rotate while the stud bolt element 9 is screwed within it.

[0051] The lower nut element 17 also comprises at least one thinned portion 17b and at least one shouldered portion 17c, wherein the shouldered portion 17c has a larger transversal dimension than the transversal dimension of the thinned portion 17b. The thinned portion 17b and the shouldered portion 17c, e.g., have a cylindrical outer surface, with the shouldered portion 17c having a larger diameter than the diameter of the thinned portion 17b.

[0052] In use, the shouldered portion 17c is placed on top of the thinned portion 17b and is adapted to rest on the supporting plate 19.

[0053] In more detail, the shouldered portion 17c is joined to the thinned portion 17b on the opposite side from the anti-rotational portion 17a and, in use, the lower nut element 17 is placed with the anti-rotational portion 17a at the bottom, the thinned portion 17b in the middle and the shouldered portion 17c at the top.

[0054] Conveniently, the supporting plate 19 comprises at least one vertical slab portion 19a which is provided with at least one passage bore 22 wherein at least one threaded connecting pin 23 is insertable which can be screwed into the lower spacer element 14.

[0055] For this purpose, it is noticed that the lower spacer element 14 has a lateral surface 14a which is provided with at least one threaded slit 14b into which the threaded connecting pin 23 can be screwed.

[0056] This allows the supporting plate 19 to be joined to the lower spacer element 14. Preferably, two passage bores 22, two threaded connecting pins 23 and two threaded slits 14b may be provided, so as to give more stability to the connection between the supporting plate 19 and the lower spacer element 14.

[0057] Advantageously, the supporting plate 19 also comprises at least one horizontal slab portion 19b which is provided with: at least one open slot 24, into which the thinned portion 17b of the lower nut element 17 is insertable; and at least one upper face 25 adapted to receive and support the shouldered portion 17c of the lower nut element 17.

[0058] The fact that the horizontal slab portion 19b may be provided with at least one open slot 24 means that horizontal slab portion 19b has a cavity closed on three sides and open on a fourth side, defining a kind of fork.

[0059] The open slot 24 is sized so as to accommodate the thinned portion 17b of the lower nut element 17 (i.e., with a slightly larger width than the diameter of the thinned portion 17b) and to allow the shouldered portion 17c to rest on the upper face 25 (i.e., with a smaller width than the diameter of the shouldered portion 17c).

[0060] Advantageously, the thickness of the supporting plate 19 is lower than the height of the thinned portion 17b; this particular expedient is of considerable importance in signaling to the outside any possible break of the stud bolt element 9, as will be more fully elucidated later in this disclosure.

[0061] Conveniently, the horizontal slab portion 19b also comprises at least one access slot 26 to the fastening screw 21.

[0062] This means that the access slot 26 is sized to allow the insertion within it of a screwing tool (e.g., screwdriver, hexagonal Allen wrench, other) adapted to screw and unscrew the fastening screw 21 without necessarily having to disassemble the supporting plate 19 from the lower spacer element 14; for example, the access slot 26 has a circular shape with a larger diameter than the diameter / cross- sectional dimension of the screwing tool.

[0063] This allows for the pre-assembly of a set of components, shown in Figure 5 and consisting of the lower spacer element 14, the supporting plate 19, the lower nut element 17, the fastening screw 21 and the threaded connecting pins 23, which set can in turn be fastened to the upper attachment portion 7 of the lower tower section 2 by simply screwing only the fastening screw 21 into the threaded hole 7b, thus greatly simplifying the assembly operations.

[0064] The fact that the supporting plate 19 comprises a vertical slab portion 19a and a horizontal slab portion 19b makes it possible to produce the plate itself in a practical and economical way, e.g. by starting from a single slab and bending it at 90° using known bending techniques.

[0065] Conveniently, in the embodiment shown in the figures, each linking joint 8 comprises two stud bolt elements 9, two upper nut elements 16 and two lower nut elements 17; in addition, the upper spacer element 12 is provided with two upper holes 13, just as the lower spacer element 14 is provided with two lower holes 15, while the horizontal slab portion 19b is provided with two open slots 24, each intended to receive one of the two lower nut elements 17.

[0066] This means that the horizontal slab portion 19b is substantially shaped like a trident or a comb with three teeth.

[0067] It is easy to appreciate, however, that alternative embodiments are possible wherein each linking joint 8 may comprise a different number of stud bolt elements 9, upper nut elements 16 and lower nut elements 17 and, consistently, the horizontal slab portion 19b may also comprise a different number of open slots 24.

[0068] The operation of this invention is as follows.

[0069] During the tower assembly operations of the tower crane 1, the linking joints 8 are mounted on the relevant attachment portions 5, 7 of the tower sections 2, 3 while the latter are still on the ground.

[0070] Specifically, the upper spacer elements 12, the stud bolt elements 9 and the upper nut elements 16 are pre-assembled and placed with the upper spacer elements 12 on top of the lower attachment portions 5 of the upper tower section 3, the stud bolt elements 9 inserted therein and the upper nut elements 16 screwed to the upper threaded ends 10, as visible in Figure 3.

[0071] The lower spacer element 14, the supporting plate 19, the lower nut elements 17, the fastening screw 21 and the threaded connecting pins 23, on the other hand, are pre-assembled with each other and attached to the upper attachment portion 7 of the lower tower section 2, as visible, again, in Figure 3.

[0072] At this point, the lifting and lowering of the upper tower section 3 from above can be done so that the stud bolt elements 9 are threaded directly within the upper attachment portions 7 of the lower tower section 2; in this way, the stud bolt elements 9 end up automatically passing through the lower holes 15 and stop at the lower nut elements 17 which, through the supporting plate 19, are maintained at the alignment position with the lower holes 15.

[0073] In this configuration, the operators in charge of the assembly can proceed to screwing the stud bolt elements 9 into the lower nut elements 17 and to tightening the upper nut elements 16 under the safest conditions, without special efforts and completely eliminating the risk of heavy objects falling from the tower crane 1, since all the components of the linking joints 8 are already preassembled and in place.

[0074] In addition, it is noticed that the presence of the supporting plate 19 makes it possible to prevent the accidental falling of objects even if one of the stud bolt elements 9 breaks.

[0075] This circumstance is illustrated in Figure 6, which shows an intact stud bolt element 9 (left) and a broken stud bolt element 9 (right), wherein the upper section of the stud bolt element 9 that broke remains hanging due to the fact that its upper nut element 16 remains resting on the upper spacer element 12, while the lower section of the stud bolt element 9 that broke and its lower nut element 17 remain resting on the supporting plate 19.

[0076] From Figure 6, it is also easy to appreciate how the special expedient of providing a thickness of the supporting plate 19 which is less than the height of the thinned portion 17b allows the stud bolt elements 9 to be signaled at the outside; in fact, as a result of the breakage, the right stud bolt element 9 lowers a few millimeters with respect to the left stud bolt element 9, provided that the force of gravity pushes it down until it rests on the supporting plate 19.

[0077] The difference in height between the intact stud bolt element 9 and the broken stud bolt element 9 allows maintenance workers to notice the breakage and be able to take action to remove and replace the broken stud bolt element 9.

[0078] Figure 7 shows an alternative embodiment of the tower crane 1 that is substantially identical to the embodiment shown in Figures 2 through 6 except that the upper threaded end 10 of the stud bolt elements 9 comprises at least one prismatic portion 27 adapted to be connected to a tensioning tool.

[0079] As is well known, the tensioning tools find application whenever screws and bolts need to be tightened with the utmost precision.

[0080] In fact, by means of a tensioning tool, the same preload can be applied to each screw and the tightening forces can be evenly distributed, thus achieving a perfect match between the spacer elements 12, 14, the nut elements 16, 17 and the attachment portions 5, 7 of the tower sections 2, 3.

[0081] In the embodiment shown in Figure 7, the prismatic portion 27 is made protruding; alternative embodiments cannot however be ruled out wherein the prismatic portion 27 may be of the “recessed” type, i.e., may consist of a cavity made in the upper threaded end 10, or may consist of an equivalent conformation. Finally, it is clarified that the present invention covers not only the previously described and illustrated tower crane 1 but also the linking joint 8 for tower crane which allows the attachment portions 5, 7 of the tower sections 2, 3 to be joined and stably connected together, i.e., a lower attachment portion 5 of the upper tower section 3 to an upper attachment portion 7 of the lower tower section 2.

[0082] In this regard, it should be noticed that the linking joint 8 according to the invention comprises: at least one stud bolt element 9 provided with an upper threaded end 10 and with a lower threaded end 11; at least one upper spacer element 12, which can be placed on top of a lower attachment portion 5 of the upper tower section 3 and provided with at least one upper hole 13 wherein the stud bolt element 9 can be inserted; at least one lower spacer element 14, which can be placed under an upper attachment portion 7 of the lower tower section 2 and provided with at least one lower hole 15 wherein the stud bolt element 9 can be inserted; at least one upper nut element 16 which can be screwed onto the upper threaded end 10; at least one lower nut element 17 which can be screwed onto the lower threaded end 11; fastening means 18 configured to fasten the lower spacer element 14 to the upper attachment portion 7 of the lower tower section 2; and at least one supporting plate 19 associable with the lower spacer element 14 and adapted to support the lower nut element 17 in a position of alignment with the lower hole 15.

[0083] It has in practice been ascertained that the described invention achieves the intended objects and, in particular, the fact is emphasized that it enables crane tower erection operations to be carried out extremely easily, quickly, economically and without risk to the safety of people and the integrity of the equipment and materials at the base of the crane.

Claims

CLAIMS1) Tower crane (1) comprising: a plurality of tower sections (2, 3) which can be placed on top of each other to define a tower and provided with a base (4) having at least one lower attachment portion (5) and with a top (6) having at least one upper attachment portion (7); at least one linking joint (8) of said attachment portions (5, 7) comprising: at least one stud bolt element (9) provided with an upper threaded end (10) and with a lower threaded end (11); at least one upper spacer element (12), which can be placed on top of said lower attachment portion (5) of a tower section (2, 3) and provided with at least one upper hole (13) in which said stud bolt element (9) is insertable; at least one lower spacer element (14) which can be placed below said upper attachment portion (7) of a tower section (2, 3) and provided with at least one lower hole (15) in which said stud bolt element (9) is insertable; at least one upper nut element (16) which can be screwed onto said upper threaded end (10); at least one lower nut element (17) which can be screwed onto said lower threaded end (11); characterized by the fact that said linking joint (8) comprises: fastening means (18) of said lower spacer element (14) to said upper attachment portion (7) of a tower section (2, 3); and at least one supporting plate (19) associable with said lower spacer element (14) and adapted to support said lower nut element (17) in a position of alignment with said lower hole (15).2) Tower crane (1) according to claim 1, characterized by the fact that said fastening means (18) comprise: at least one through opening (20) made in said lower spacer element (14); and at least one fastening screw (21) insertable in said through opening (20) andscrewable in said upper atachment portion (7) of a tower section (2, 3).3) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said lower nut element (17) comprises at least one anti-rotational portion (17a) having a substantially square cross-section.4) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said lower nut element (17) comprises at least one thinned portion (17b) and at least one shouldered portion (17c), wherein said shouldered portion (17c) has a larger transversal dimension than a transversal dimension of said thinned portion (17b) and, in use, is placed on top of said thinned portion (17b) and is adapted to rest on said supporting plate (19).5) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said supporting plate (19) comprises at least one vertical slab portion (19a) provided with at least one passage bore (22) wherein is insertable at least one threaded connecting pin (23) screwable into said lower spacer element (14).6) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said supporting plate (19) comprises at least one horizontal slab portion (19b) which is provided with: at least one open slot (24) into which said thinned portion (17b) is insertable; and at least one upper face (25) adapted to receive and support said shouldered portion (17c).7) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said horizontal slab portion (19b) comprises at least one access slot (26) to said fastening screw (21).8) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that: said linking joint (8) comprises two of said stud bolt elements (9), two of said upper nut elements (16) and two of said lower nut elements (17); said upper spacer element (12) is provided with two of said upper holes (13); said lower spacer element (14) is provided with two of said lower holes (15);said horizontal slab portion (19b) is provided with two of said open slots (24).9) Tower crane (1) according to one or more of the preceding claims, characterized by the fact that said upper threaded end (10) comprises at least one prismatic portion (27) adapted to be connected to a tensioning tool.10) Linking joint (8) for tower crane, comprising: at least one stud bolt element (9) provided with an upper threaded end (10) and with a lower threaded end (11); at least one upper spacer element (12), which can be placed on top of a lower attachment portion (5) of a tower section (2, 3) and provided with at least one upper hole (13) wherein said stud bolt element (9) is insertable; at least one lower spacer element (14) which can be placed below an upper attachment portion (7) of a tower section (2, 3) and provided with at least one lower hole (15) into which said stud bolt element (9) is insertable; at least one upper nut element (16) which can be screwed onto said upper threaded end (10); at least one lower nut element (17) which can be screwed onto said lower threaded end (11); characterized by the fact that it comprises: fastening means (18) of said lower spacer element (14) to said upper attachment portion (7); and at least one supporting plate (19) associable with said lower spacer element (14) and adapted to support said lower nut element (17) in a position of alignment with said lower hole (15).

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