u-shaped clip / tenon connection with intermediate insert between tenon and pin

Abstract

A clevis / tenon connection device (3) comprising: - a clevis (32) comprising two plates (33) defining a slot (34) and having a clevis aperture (35) aligned on a mounting axis (300); - a tenon (30) having a tenon aperture formed therein and shaped to engage inside the slot in the clevis; and - a pin rod (36) shaped to pass through the clevis aperture and the tenon aperture in an assembled position, wherein the tenon engages inside the slot in the clevis; - a cylindrical intermediate insert (5) mounted on the tenon and inside the tenon aperture and having an insert aperture (50) through which the pin rod passes in the assembled position. In a common application, such a clevis / tenon joint is used to assemble structural elements of a crane.

Description

Technical Field

[0001] The present invention relates to a U-shaped clamp / tenon connection device for assembling a first structural element and a second structural element together.

[0002] More specifically, the present invention relates to a U-shaped clamp / tenon connection device, comprising a U-shaped clamp, a tenon engaged within the U-shaped clamp, and a pin passing through the U-shaped clamp and the tenon to assemble them.

[0003] The present invention discovers a preferred, but not limiting, application for assembling two structural elements of a crane (partial assembly crane, tower crane, or automated assembly crane), and more specifically for assembling a cantilever support and a counterweight, as well as a rotating pivot for assembling the cantilever support into a tower crane. Background Technology

[0004] Cranes used on construction sites for building and civil engineering projects, as known in various methods, include a mast with a rotating upper section mounted at the top. This rotating upper section is oriented about a vertical axis and includes a cantilever and a counterweight cantilever. The rotating upper section typically includes a pivot with a cantilever support mounted on top. The cantilever and counterweight cantilever are assembled on either side of the cantilever support.

[0005] One solution for assembling a balance cantilever onto a cantilever support includes using at least one U-clamp / tenon connection device (also known as a pin connection device), comprising a U-clamp fixed to the cantilever support, a tenon fixed to the balance cantilever, and a pin passing through the U-clamp and the tenon mounted within the U-clamp. The U-clamp includes: two plates extending parallel to and facing each other, defining a slot for receiving the tenon, and provided with a U-clamp orifice allowing the pin to pass through; and a tenon including a tenon orifice through which the same pin passes.

[0006] On a crane, the U-shaped clamp / tenon connection that ensures the assembly between the cantilever support and the rotating pivot, and between the cantilever support and the counterweight, receives many loads. These loads originate from vertical loads and moments, which are generated by the lifting load suspended on the cantilever, the counterweight mounted on the counterweight, the self-weight of the structure (cantilever, counterweight, strut, etc.), crosswinds, and the acceleration and braking forces (slewing torque) during the rotation of the rotating upper part.

[0007] However, these loads are not constant because they depend on the cantilever angle, the mass of the lifted load, the wind speed and direction, and the slewing torque. When the crane is operating, these loads may reverse at the U-clamp / tenon joint, subjecting the U-clamp / tenon joint to alternating tensile and compressive forces.

[0008] Therefore, the problem of micro-vibration erosion of the components of the U-shaped clamp / tenon connection device has emerged; micro-vibration erosion refers to the local crushing of the material due to excessive pressure field in the contact area between the two parts.

[0009] Therefore, this type of fretting corresponds to plastic deformation of the material, which in the long run can lead to gaps in the connections (between the U-clamp and the pin, and between the tenon and the pin), especially under alternating loads. Once gaps appear, wear will increase exponentially. Such gaps in the connections may eventually degrade the mechanical performance of the crane and require overhaul, which would keep the crane stationary for extended periods.

[0010] The first solution involves increasing the thickness or size of the components of the U-clamp / tenon connection (i.e., the U-clamp, tenon, and pin); however, this oversized solution is usually not feasible due to economic, weight, and space constraints.

[0011] The second solution involves welding steel plates (also known as wear plates) to both sides of the tenon, which reduces micro-vibration erosion without making the components of the U-clamp / tenon connection too thick or large.

[0012] However, as crane capacity increases, the forces experienced at the U-shaped clamp / tenon joint and consequently at the wear plate become increasingly higher. Furthermore, due to the flexibility of the pin, these forces are unevenly distributed, resulting in a larger proportion of the force being transmitted at the shear plane (at both sides of the tenon), where the pin experiences very little deformation compared to the middle plane of the tenon.

[0013] Furthermore, the wear plates welded to both sides of the tenon bear most of the load transmitted through the U-shaped clamp / tenon connection, making it difficult to produce suitable weld beads. In fact, welding reduces resistance to altered stress cycles, which locally changes the material's properties. An optimized wear plate shape must be used to distribute stress within the weld, requiring a larger gap. However, in some locations, geometric constraints limit the available space, thus preventing the production of such weld beads and rendering the use of wear plates in these locations ineffective for high-capacity cranes.

[0014] Therefore, it is necessary to address this micro-vibration erosion problem, especially under high loads and in confined spaces at U-shaped clamp / tenon joints. Summary of the Invention

[0015] Therefore, one object of the present invention is to solve the problems of micro-vibration erosion and premature wear in U-shaped clamp / tenon joints using a compact and optimized solution.

[0016] Therefore, the present invention proposes a U-shaped clamp / tenon connection device, which includes:

[0017] - A U-shaped clamp comprising two plates that extend parallel to each other and face each other and define a slot, the two plates having corresponding U-shaped clamp openings aligned on the mounting axis;

[0018] - A tenon, wherein a tenon opening is formed, the tenon being configured to engage within a slot of a U-shaped clamp, the tenon opening being aligned with the U-shaped clamp opening along the mounting axis; and

[0019] - A pin, configured to pass through a U-shaped clamping hole and a tenon hole in the assembled position, wherein the tenon engages inside the U-shaped clamping slot.

[0020] The notable feature of the U-shaped clamp / tenon connection device is that it includes an intermediate insert mounted on the tenon and within the tenon orifice, and the intermediate insert is cylindrical and has an insert orifice through which a pin passes in the assembled position, and the intermediate insert includes a first end and a second end, the first end having a collar abutting against a first face of the tenon facing one of the two plates, and the second end protruding from a second face of the tenon facing the other of the two plates, wherein an annular stop is mounted around the second end to axially block the intermediate insert inside the tenon orifice.

[0021] Therefore, the intermediate insert is fitted into the tenon hole, thus satisfying the requirements for fretting between the pin and the intermediate insert, and between the insert and the tenon plate, without the need to weld the tenon and pin or enlarge their dimensions. In effect, the load passes through the insert and is distributed along its length, thereby helping to solve the fretting problem.

[0022] Furthermore, the annular stop is configured to hold the intermediate insert in place, and during operation, the intermediate insert is clamped between the plates of the U-shaped clamp, thereby eliminating any risk of separation between the intermediate insert and the tenon.

[0023] One advantage is that such intermediate inserts do not require any weld beads and can even be implemented in limited spaces.

[0024] Another advantage is that the intermediate insert can be easily replaced in the event of wear and tear. Therefore, this invention facilitates overhauling, particularly of cranes, thereby contributing to a reduction in environmental impact.

[0025] According to one characteristic, the intermediate insert is a single-piece machined part; therefore, the intermediate insert is easy to manufacture and inexpensive.

[0026] One possibility is that the intermediate insert is made of alloy steel (such as chromium-molybdenum alloy steel), which is advantageous for long-term resistance to alternating loads.

[0027] According to another possibility, the intermediate insert is installed inside the tenon hole with an installation gap to facilitate the assembly of the intermediate insert inside the tenon hole without the need for a press.

[0028] Advantageously, the second end includes a groove in which an annular stop is mounted, thereby axially holding the intermediate insert in a manner similar to a spring ring.

[0029] In a particular embodiment, the annular stop comprises two half-rings fixed together, thereby allowing the annular stop to be placed more easily within the groove.

[0030] According to one possibility, at least one protective element is welded to the second surface of the tenon around the periphery of the annular stop, the at least one protective element forming a boss with a given thickness protruding from the second surface, thereby extending beyond the annular stop along the mounting axis.

[0031] Therefore, this protective element protects the annular stop from being crushed by the U-shaped clamp, especially during potential collisions with the plate when the tenon is engaged inside the slot of the U-shaped clamp. The protective element can also perform a guiding or indexing function to facilitate tenon engagement inside the slot of the U-shaped clamp.

[0032] According to another possibility, at least one protective element has an arcuate shape and / or a circular cross-section, such shapes are advantageous for facilitating the guidance of the tenon into the slot of the U-shaped clamp.

[0033] The present invention also relates to an assembly comprising a first structural member and a second structural member assembled by means of a U-shaped clamp / tenon connection device as described above, wherein the U-shaped clamp is fixed to the first structural member and the tenon is fixed to the second structural member, and wherein the U-shaped clamp / tenon connection device is in its assembled position, wherein the tenon is inserted into a slot in the U-shaped clamp, and wherein a pin passes through an opening in the U-shaped clamp and an opening in the insert.

[0034] Based on one characteristic, the first structural member and the second structural member correspond to the structural members of the crane.

[0035] According to another feature, one of the first structural member and the second structural member corresponds to a cantilever bracket, and the other of the first structural member and the second structural member is selected from a rotary pivot, a counterweight cantilever, a cantilever, and a strut.

[0036] In fact, intermediate inserts are particularly well-suited for these configurations. Attached Figure Description

[0037] Other features and advantages of the invention will become apparent from the following detailed description of non-limiting examples given with reference to the accompanying drawings, in which:

[0038] Figure 1 This is a schematic side view of the rotating upper section of a pitching cantilever crane, showing a rotating pivot with a cantilever support mounted on top, cantilever and counterweight cantilever arranged on both sides of the cantilever support, and a support column mounted on top of the cantilever support.

[0039] Figure 2 yes Figure 1 A schematic exploded side view of the rotating upper part of the crane;

[0040] Figure 3 yes Figure 1 A schematic side view of the cantilever bracket, showing the tenon for connection with the counterweight cantilever.

[0041] Figure 4 yes Figure 3 A schematic perspective view of a tenon for connecting to a balance cantilever bracket, wherein an intermediate insert is installed in the tenon hole of the tenon.

[0042] Figure 5 yes Figure 3 A schematic perspective view of the tenon of the cantilever bracket, on which the intermediate insert is mounted. The tenon is positioned opposite the slot of the U-shaped clamp provided on the balance cantilever, and the proper position of the pin on the U-shaped clamp is shown.

[0043] Figure 6 yes Figure 1 A schematic perspective view of the connection between the cantilever bracket and the counterweight cantilever, wherein two tenons of the cantilever bracket engage in two corresponding U-shaped clamps of the counterweight cantilever, each of the two tenons being equipped with an intermediate insert.

[0044] Figure 7 It is a schematic perspective exploded view of the intermediate insert and the associated annular stop;

[0045] Figure 8 It is used for Figure 1 A schematic axial sectional view of the pin connection device connecting the cantilever bracket and the counterweight cantilever. Detailed Implementation

[0046] Figure 1 and Figure 2The rotating upper section 1 of a crane is shown. This crane is a pitching jib crane and a component assembly crane. The crane includes a mast that extends along a vertical axis Z and has a top 90. The rotating upper section 1 is mounted on this top via a rotating pivot 10 (also called a slewing device), thus allowing the rotating upper section to rotate (or be rotatably movable) about the vertical axis Z.

[0047] The rotating upper part 1 includes a cantilever support 11 located at the top 90 of the mast, a cantilever 12 (composed of several cantilever elements) pivotally mounted at the front of the cantilever support 11, a counterweight cantilever 13 mounted at the rear of the cantilever support 11, and a strut 14 mounted on the counterweight cantilever 13.

[0048] The cantilever bracket 11 is mounted on the rotating pivot 10, for example by means of several U-shaped clamps / tenons connecting devices 41, so that the cantilever bracket 11 is rotatably fixed to the rotating pivot 10.

[0049] The cantilever 12 is movably mounted to rotate about a horizontal axis on the cantilever bracket 11, so that the cantilever 12 can be raised and lowered.

[0050] The balance cantilever 13 is connected by two U-shaped clamps / tenons 3 (such as...) Figure 6 (See image) Mounted on cantilever support 11, thus being rotatably fixed to cantilever support 11. The counterweight 13 includes a platform for supporting the equipment, specifically including a pitch winch (not shown) connected to the cantilever 12 for raising / lowering the cantilever 12, and a hoisting winch (not shown) connected to a lifting hook 15 located at the end 16 of the cantilever 12 for lifting the load. The counterweight 13 also carries a counterweight 17.

[0051] More specifically, the pitch winch has a drum around which a pitch cable is wound, the cable passing over a pulley 17 arranged on a support 14 and also over a pitch block 18 connected to the end 16 of the cantilever 12 by a system of levers.

[0052] The hoisting winch has a drum on which the hoisting cable is wound. The cable passes through a support column 14, over pulleys arranged on the support column 14 and the cantilever 12, and is then guided toward the end 16 of the cantilever 12 to be secured to a lifting hook 15, whether or not the cable is threaded through it. During operation of the crane, the load to be lifted is suspended from the lifting hook 15 and located below the end 16 of the cantilever 12.

[0053] The counterweight 13 can be mechanically connected to the cantilever support 11 by means of one or two reinforcing beams 19 extending between the cantilever support 11 and the lower side of the counterweight 13, each reinforcing beam 19 being mounted on the cantilever support 11, for example by means of a U-shaped clamp / tenon connection device 42.

[0054] The strut 14 extends obliquely upward and backward from the cantilever bracket 11 and includes a base 20 mounted on the balance cantilever 13, for example by means of a U-shaped clamp / tenon connection 43, and an opposite top 21.

[0055] The rotating upper part 1 also includes at least one tie rod 21, which is fixed at one end to the top 21 of the support column 14 and at the other end to the balance cantilever 13, for example by means of a U-shaped clamp / tenon connection. Thus, in operation, the balance cantilever 13 is suspended from the support column 14 by means of the tie rod 21.

[0056] Regarding the U-shaped clamp / tenon connection device 41 that ensures the cantilever bracket 11 is assembled on the rotating pivot 10, the lower portion of the cantilever bracket 11 includes a tenon 110 in which a tenon orifice 111 is formed, and the upper portion of the rotating pivot 10 includes a U-shaped clamp 100, each of the U-shaped clamps including two opposing plates defining a slot and provided with a corresponding U-shaped clamp orifice, and a pin (not shown) passes through the U-shaped clamp orifice and the tenon orifice 111 in the assembled position, in which the tenon 110 engages inside the corresponding slot of the U-shaped clamp 100.

[0057] For these U-shaped clamp / tenon joints 41, steel plates 112 are welded to both sides of the tenon 110. It should be noted that these steel plates 112 have an optimized shape (in this case, a teardrop shape) to distribute stress within the weld at locations where space constraints allow (i.e., the lower portion of the cantilever bracket 11).

[0058] Regarding the two U-shaped clamp / tenon connection devices 3 that ensure the balance cantilever 13 is assembled on the cantilever bracket 11, the upper portion of the cantilever bracket 11 includes two parallel tenons 30, in which corresponding tenon openings 31 are formed, and the rear portion of the balance cantilever 13 includes two U-shaped clamps 32, each of which includes two opposing plates 33, which define a slot 34 and are provided with corresponding U-shaped clamp openings 35 aligned along the mounting axis 300, and two pins 36 pass through the U-shaped clamp openings 35 and the tenon openings 31 in the assembled position (in Figure 6 and Figure 8 As can be seen in the image, in this assembled position, the tenon 30 engages within the corresponding slot 34 of the U-shaped clamp 32. Therefore, each of the two U-shaped clamp / tenon connecting devices 3 includes one of the two tenons 30, one of the two U-shaped clamps 32, and one of the two pins 36.

[0059] At the upper portion of the cantilever bracket 11, a pivot hinge 120 of the cantilever 12 is also received, making the space in this upper portion so limited that it is impossible to provide a steel plate with an optimized shape. Therefore, each of the two U-shaped clamp / tenon connection devices 3 includes an intermediate insert 5 mounted on the tenon 30 and inside the tenon opening 31, the intermediate insert 5 being cylindrical and having an insert opening 50 through which the pin 36 passes in the assembled position.

[0060] The intermediate insert 5 is a single-piece machined part made of alloy steel (e.g., chromium-molybdenum alloy steel).

[0061] The intermediate insert 5 includes a first end 51 and a second end 52. The first end has a collar abutting against a first surface 301 of the tenon 30 facing one of the two plates 33. The second end protrudes from a second surface 302 of the tenon 30 facing the other of the two plates 33. An annular stop 53 is mounted around the second end 52 to axially block the intermediate insert 5 within the tenon opening 31. The second end 52 of the intermediate insert 5 has a groove 54 in which the annular stop 53 is mounted.

[0062] like Figure 4 and Figure 7 As can be seen, the annular stop 53 includes two semi-rings 55, which are fixed together by means of two keys 56, which are screwed between the ends of the two semi-rings 55.

[0063] like Figure 4 , Figure 5 and Figure 8 As can be seen, at least one protective element 37 (in the form of an arcuate weld with a circular cross-section) is welded to the second surface 302 of the tenon 30 around the periphery of the annular stop 53.

[0064] Therefore, the protective element 37 forms a boss that protrudes from the second face 302 of the tenon 30 and has a given thickness (corresponding to the diameter of the weld bead) and thus extends along the mounting axis 300 beyond the annular stop 53.

[0065] like Figure 8 As can be seen, two locking rods 38 pass through the pins 36 on both sides of the U-shaped clamp 32 in order to axially fix the pins 36 in the appropriate position.

Claims

1. A U-shaped clamp / tenon connection device (3), comprising: - U-shaped clamp (32), which includes two plates (33) extending parallel to each other and facing each other and defining a slot (34), the two plates (33) having corresponding U-shaped clamp openings (35) aligned on the mounting axis (300). - A tenon (30) having a tenon opening (31) therein, the tenon (30) being formed to engage inside the slot (34) of the U-shaped clamp (32), the tenon opening (31) of the tenon being aligned with the U-shaped clamp opening (35) along the mounting axis (300); and - A pin (36) is formed to pass through the U-shaped clamp opening (35) and the tenon opening (31) in the assembled position, wherein the tenon (30) engages inside the slot (34) of the U-shaped clamp (32); The U-shaped clamp / tenon connection device (3) is characterized in that it includes an intermediate insert (5) mounted on the tenon (30) and inside the tenon opening (31), and the intermediate insert (5) is cylindrical and has an insert opening (50), the pin (36) passing through the insert opening in the assembled position, and wherein the intermediate insert (5) includes a first end (51) and a second end (52), the first end having a collar abutting against a first face (301) of the tenon (30) opposite to one of the two plates (33), the second end protruding from a second face (302) of the tenon (30) opposite to the other of the two plates (33), wherein an annular stop (53) is mounted around the second end (52) to axially block the intermediate insert (5) inside the tenon opening (31).

2. The U-shaped clamp / tenon connecting device (3) according to claim 1, wherein, The intermediate insert (5) is a single-piece machined part.

3. The U-shaped clamp / tenon connecting device (3) according to claim 1 or 2, wherein, The intermediate insert (5) is made of alloy steel, for example, chromium-molybdenum alloy steel.

4. The U-shaped clamp / tenon connecting device (3) according to any one of the preceding claims, wherein, The spacer insert (5) is installed inside the tenon hole (31) with an installation gap.

5. The U-shaped clamp / tenon connecting device (3) according to any one of the preceding claims, wherein, The second end (52) has a groove (54), and the annular stop (53) is installed in the groove.

6. The U-shaped clamp / tenon connecting device (3) according to claim 5, wherein, The annular stop (53) comprises two half-rings (55) fixed together.

7. The U-shaped clamp / tenon connecting device (3) according to any one of the preceding claims, wherein, At least one protective element (37) is welded to the second face (302) of the tenon (30) at the periphery of the annular stop (53). Such at least one protective element (37) forms a boss that protrudes from the second face (302) to a given thickness, thereby extending beyond the annular stop (53) along the mounting axis (300).

8. The U-shaped clamp / tenon connecting device (3) according to claim 7, wherein, At least one protective element (37) has an arcuate shape and / or a circular cross-section.

9. An assembly comprising a first structural element (13) and a second structural element (11) assembled by means of a U-shaped clamp / tenon connection device (3) according to any one of the preceding claims, wherein, The U-shaped clamp (32) is fixed to the first structural element (13), and the tenon (30) is fixed to the second structural element (11), wherein the U-shaped clamp / tenon connecting device (3) is in its assembled position, wherein the tenon (30) is inserted into the slot (34) of the U-shaped clamp (32), and wherein the pin (36) passes through the U-shaped clamp orifice (35) and the insert orifice (50).

10. The component of claim 9, wherein, The first structural element (13) and the second structural element (11) correspond to the structural elements of the crane.

11. The component of claim 10, wherein, One of the first structural element (13) and the second structural element (11) corresponds to a cantilever bracket, while the other of the first structural element (13) and the second structural element (11) is selected from a rotary pivot, a balance cantilever, a cantilever, and a strut.

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