Slewing assembly and tower crane

Abstract

The present invention belongs to the technical field of construction machinery, and specifically, relates to a slewing assembly and a tower crane. The slewing assembly includes a slewing support bearing, an upper support, and a lower support. The slewing support bearing includes a slewing raceway. The upper support is pivotally connected to the upper part of the slewing support bearing and includes an upper support barrel. The lower support is connected to the lower part of the slewing support bearing and includes a lower support barrel. The slewing raceway, the upper support barrel, and the lower support barrel are coaxially arranged and have the same radius. This arrangement allows the upper support barrel, the lower support barrel, and the slewing raceway to be located on the circumferential wall of the same cylinder, so as to provide good support for the load generated by the upper assembly connected to the slewing assembly, prevent the generation of eccentric torque, reduce abnormal noise during rotation, and increase the service life of the slewing support bearing.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction machinery, and in particular relates to a slewing assembly and a tower crane. Background Art

[0002] The slewing assembly is located between the tower crane tower body and the upper structure (boom, balance arm, etc.), and is mainly used to connect the upper structure and the tower body to realize the slewing function of the upper structure relative to the tower body. The slewing assembly includes an upper support, a slewing support bearing, and a lower support that are connected in sequence along the height direction of the tower body, wherein the slewing support bearing includes an outer ring, an inner ring, and a slewing raceway formed between the outer ring and the inner ring. At present, the upper support and lower support of the existing slewing assembly and the raceway of the slewing support bearing are not on the circumferential wall of the same cylinder. When the load on the slewing assembly is transmitted to the tower body through the upper support barrel, the slewing support bearing, and the lower support barrel, an eccentric torque will be generated, which will reduce the service life of the slewing support bearing and easily produce abnormal noise during the slewing operation. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides a slewing assembly and a tower crane, which have good mechanical properties, prevent the generation of eccentric torque, reduce abnormal noise during the rotation process, and increase the service life of the slewing support bearing.

[0004] To achieve the above-mentioned object, the present invention provides a first aspect of a slewing assembly for a tower crane, the slewing assembly comprising:

[0005] Slewing bearings, including slewing raceways;

[0006] an upper support pivotally connected above the slewing bearing and comprising an upper support barrel; and

[0007] A lower support is connected below the slewing bearing and includes a lower support barrel;

[0008] Among them, the rotary raceway, the upper support barrel and the lower support barrel are coaxially arranged and have equal radii.

[0009] Optionally, the upper support further comprises:

[0010] The upper support cover plate is arranged on the top of the upper support barrel;

[0011] The upper support lower cover plate is arranged at the bottom end of the upper support barrel and is connected to the slewing support bearing;

[0012] An intermediate support plate extends outwardly from the upper support barrel along the circumferential direction and is spaced apart from the upper support lower cover plate and the upper support lower cover plate; and

[0013] The box-type mounting ear seat has a bottom end connected to the middle support plate and a top end extending upward and beyond the upper support cover plate.

[0014] Optionally, the distance between the middle support plate and the upper cover plate of the upper support and the distance between the middle support plate and the lower cover plate of the upper support are both 400 mm to 600 mm.

[0015] Optionally, the upper support lower cover plate includes a circumferential skirt extending outward from the upper support barrel along the circumferential direction and connected to the slewing support bearing.

[0016] Optionally, the box-type mounting ears include:

[0017] A box-shaped fixing portion connected between the upper support cover plate and the middle support plate and connected to the upper support barrel; and

[0018] The ear seat connecting portion extends upward from the top end of the box-shaped fixing portion and is provided with a pin shaft connecting hole.

[0019] Optionally, the ear seat connecting portion is further provided with a hanging ear hole.

[0020] Optionally, the upper support is provided with two box-shaped mounting ears on both sides of the Y-axis, the two box-shaped mounting ears on one side of the Y-axis are symmetrically arranged relative to the X-axis, the box-shaped mounting ears on one side of the X-axis are equidistant from the X-axis, and the distance between the center of the pin connecting hole on one side of the Y-axis and the Y-axis is unequal to the distance between the center of the pin connecting hole on the other side of the Y-axis and the Y-axis; wherein,

[0021] The X-axis is an axis passing through the central axis of rotation and parallel to the extension direction of the tower crane boom section, and the Y-axis is an axis passing through the central axis of rotation and perpendicular to the X-axis.

[0022] Optionally, the distance between the center of the pin connecting hole on one side of the Y axis and the Y axis is 1150 mm to 1200 mm; the distance between the center of the pin connecting hole on the other side of the Y axis and the Y axis is 1300 mm to 1350 mm.

[0023] Optionally, the lower support further comprises a plurality of lifting support structures evenly spaced along the circumference, and the lifting support structures comprise diagonal bracing angle steels for enhancing connection strength.

[0024] Optionally, the included angle between the diagonal bracing angle steel and the horizontal plane is 75° to 83°.

[0025] Optionally, a speed sensor for detecting the working condition of the slewing bearing is further provided in the upper support.

[0026] A second aspect of the present invention provides a tower crane, which includes the above-mentioned slewing assembly.

[0027] In the slewing assembly of the present invention, the slewing raceway, upper support barrel, and lower support barrel are coaxially arranged with equal radius. In other words, the upper support barrel, lower support barrel, and slewing raceway are located on the circumferential wall of the same cylinder. This arrangement enables the slewing assembly to effectively support the load generated by the upper assembly, prevent eccentric torque, reduce abnormal noise during rotation, and extend the service life of the slewing support bearing.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 A perspective view of a rotary assembly provided according to a specific embodiment of the invention;

[0031] Figure 2 A partial cross-sectional view of a rotary assembly provided according to a specific embodiment of the present invention;

[0032] Figure 3 for Figure 1 A top view of the rotary assembly in FIG.

[0033] Figure 4 A front view of a box-type mounting ear seat provided according to a specific embodiment of the present invention;

[0034] Figure 5 for Figure 4 Cross-section view of the mid-box mounting ears.

[0035] Explanation of reference numerals: 100, upper support; 110, upper support barrel; 120, upper support upper cover plate; 130, upper support lower cover plate; 131, circumferential skirt; 140, intermediate support plate; 150, box-type mounting ear seat; 151, box-type fixing portion; 152, ear seat connecting portion; 1521, pin shaft connecting hole; 1522, lifting ear hole; 160, speed sensor; 170, motor mounting seat; 200, slewing bearing; 300, lower support; 310, lower support barrel; 320, jacking support structure; 321, diagonal bracing angle steel; 400, drive motor DETAILED DESCRIPTION

[0036] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0038] In the embodiments of the present invention, unless otherwise specified, directional words such as "up, down, top, bottom" are usually used to describe the relative positional relationships of components in the directions shown in the drawings or in the vertical, perpendicular or gravity directions.

[0039] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0040] Figure 1 It is a three-dimensional view of a rotary assembly provided according to a specific embodiment of the invention. Figure 2 A partial cross-sectional view of a rotary assembly according to a specific embodiment of the present invention is shown. Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a slewing assembly for a tower crane. The slewing assembly includes a slewing bearing 200, an upper support 100, and a lower support 300. The slewing bearing 200 includes a slewing raceway. The upper support 100 is pivotally connected to the upper portion of the slewing bearing 200 and includes an upper support barrel 110. The lower support 300 is connected to the lower portion of the slewing bearing 200 and includes a lower support barrel 310. The slewing raceway, the upper support barrel 110, and the lower support barrel 310 are coaxially arranged and have equal radii.

[0041] Specifically, the slewing bearing 200 includes a slewing raceway, in which rolling elements are arranged, and driven by a power device (such as a motor), the outer ring and the inner ring rotate relative to each other. Figure 1 and Figure 2 As shown, in the illustrated embodiment, the inner ring of the slewing bearing 200 is a gear ring and is fixedly connected to the lower support 300 with a thread, and the outer ring of the slewing bearing 200 is connected to the upper support 100. A motor mounting seat 170 is provided in the upper support 100, and a drive motor 400 is fixedly mounted on the motor mounting seat 170. A gear meshing with the gear ring is pivotally connected to the output shaft of the drive motor 400, and the upper support 100 is pivoted under the action of the drive motor 400.

[0042] Specifically, in this embodiment, the slewing raceway, upper support barrel 110, and lower support barrel 310 are coaxially arranged with equal radii. In other words, the upper support barrel 110, lower support barrel 310, and slewing raceway are located on the circumferential wall of the same cylinder. This effectively supports the load generated by the upper components (including the balance arm and jib) connected to the slewing assembly, prevents eccentric torque, reduces abnormal noise during slewing, and increases the service life of the slewing bearing 200.

[0043] It will be appreciated that the structure for enabling the upper support 100 to pivot relative to the lower support 300 is not limited to the illustrated embodiment. In another feasible embodiment, the outer ring of the slewing bearing 200 is fixed, while the inner ring rotates. For example, the outer ring of the slewing bearing 200 is a gear ring fixedly mounted on the lower support 300, while the inner ring of the slewing bearing 200 is connected to the upper support 100. The drive motor 400 is mounted on the upper support 100 and is equipped with a gear that meshes with the gear ring. Under the action of the drive motor 400, the upper support 100 can also pivot relative to the lower support 300.

[0044] In an embodiment of the present invention, the upper support 100 further includes an upper support upper cover plate 120, an upper support lower cover plate 130, an intermediate support plate 140, and a box-shaped mounting lug 150. The upper support upper cover plate 120 is disposed at the top end of the upper support enclosure 110. The upper support lower cover plate 130 is disposed at the bottom end of the upper support enclosure 110 and is connected to the slewing bearing 200. The intermediate support plate 140 extends outwardly from the upper support enclosure 110 in the circumferential direction and is spaced apart from the upper support upper cover plate 120 and the upper support lower cover plate 130. The box-shaped mounting lug 150 has its bottom end connected to the intermediate support plate 140 and its top end extending upward and beyond the upper support upper cover plate 120.

[0045] Furthermore, the upper support lower cover plate 130 includes a circumferential skirt 131 extending outward from the upper support barrel 110 in the circumferential direction and connected to the slewing support bearing 200 .

[0046] It should be noted that in the existing slewing assembly, the threaded connection position between the upper support 100 and the slewing bearing 200 is located in the upper support barrel 110, and the threaded connection position between the lower support 300 and the slewing bearing 200 is located in the lower support barrel 310, which makes it difficult to disassemble and maintain the slewing bearing 200 in the future. However, in this embodiment, the upper support lower cover plate 130 is connected to the bottom end of the upper support barrel 110 and includes a circumferential skirt 131, as shown in FIG. Figure 1 As shown, the circumferential skirt 131 is connected to the outer ring of the slewing bearing 200 by threads. Since the circumferential skirt 131 is located on the circumferential outer side of the upper support barrel 110, it is convenient for operators to perform maintenance.

[0047] In addition, it should be noted that in the existing slewing assembly, the bottom end of the mounting ear seat (the box-type mounting ear seat 150 in this embodiment) used to connect the tower crane boom section is connected to the upper support lower cover plate 130, and the top end extends upward and exceeds the upper support upper cover plate 120. In other words, the lower half of the existing mounting ear seat is connected between the upper support upper cover plate 120 and the upper support lower cover plate 130 to ensure the firmness of the entire mounting ear seat. As mentioned above, in this embodiment, since the upper support lower cover plate 130 also includes a circumferential skirt 131, if the lower half of the box-type mounting ear seat 150 is connected between the upper support upper cover plate 120 and the upper support lower cover plate 130, the bottom end of the box-type mounting ear seat 150 will interfere with the circumferential skirt 131. Therefore, in this embodiment, an intermediate support plate 140 is provided between the upper support upper cover plate 120 and the upper support lower cover plate 130. The bottom ends of the box-shaped mounting ears 150 are connected to the intermediate support plate 140 so as not to be positioned on the upper support lower cover plate 130. This prevents interference and simultaneously secures the box-shaped mounting ears 150. To ensure that the box-shaped mounting ears 150 can be securely fixed and facilitate the assembly and disassembly of the circumferential skirt 131 and the slewing bearing 200, preferably, the spacing between the intermediate support plate 140 and the upper support upper cover plate 120, and the spacing between the intermediate support plate 140 and the upper support lower cover plate 130, are both 400 mm to 600 mm.

[0048] Figure 4 This is a front view of a box-type mounting ear seat provided according to a specific embodiment of the present invention. Figure 5 for Figure 4 Cross-sectional view of a middle box-shaped mounting lug. In this embodiment of the present invention, the box-shaped mounting lug 150 includes a box-shaped fixing portion 151 and a lug connection portion 152. The box-shaped fixing portion 151 is connected between the upper support upper cover plate 120 and the intermediate support plate 140 and is connected to the upper support barrel 110. The lug connection portion 152 extends upward from the top of the box-shaped fixing portion 151 and is provided with a pin connection hole 1521.

[0049] like Figure 4 and Figure 5 As shown, in the illustrated embodiment, the box-shaped mounting lug 150 includes two parallel, spaced-apart vertical plates and two longitudinal plates connected between the two vertical plates. The lower halves of the two vertical plates and the two longitudinal plates are connected to form a rectangular box-shaped fixing portion 151. The box-shaped fixing portion 151 is connected to the upper support upper cover plate 120, the upper support lower cover plate 130, and the upper support barrel 110 to provide a fixed connection. The upper halves of the two vertical plates form an ear-mounted connecting portion 152. After the box-shaped fixing portion 151 is fixedly installed, the ear-mounted connecting portion 152 protrudes from the upper support upper cover plate 120. Of course, the pin connection hole 1521 is located above the upper support upper cover plate 120 and can be used to fix the tower crane boom section.

[0050] It should be noted that the conventional mounting lugs for tower crane boom sections employ a plate-like structure (flat plate). The box-shaped mounting lug 150 offers improved compressive strength compared to the conventional plate-like mounting lugs. Because the box-shaped mounting lug 150 offers improved mechanical properties, the lug connection portion 152 is further provided with a lifting lug hole 1522, thereby eliminating the need for additional lifting lugs for hoisting.

[0051] It is understandable that because the upper support barrel 110, the lower support barrel 310, and the slewing raceway are located on the circumferential wall of the same cylinder, the entire slewing assembly has excellent mechanical properties. Therefore, in the slewing assembly of the present invention, the vertical mechanical performance requirements for the upper support lower cover plate 130, the lower support upper cover plate (connected to the slewing support bearing 200), the upper support barrel 110, and the lower support barrel 310 are lower than those required for existing slewing assemblies. In other words, the upper support lower cover plate 130, the lower support upper cover plate, the upper support barrel 110, and the lower support barrel 310 can be made of thinner flat plates. Although the slewing assembly of the present invention includes an intermediate support plate 140 and uses a box-type mounting lug 150, the slewing assembly of the present invention is lighter than a tower crane of the same tonnage using existing slewing assemblies, achieving a lightweight slewing assembly.

[0052] In an embodiment of the present invention, the upper support 100 is provided with two box-type mounting ear seats 150 on both sides of the Y-axis, and the two box-type mounting ear seats 150 located on one side of the Y-axis are arranged symmetrically with respect to the X-axis. The box-type mounting ear seats 150 located on one side of the X-axis are equal in distance from the X-axis, and the distance between the center of the pin shaft connecting hole 1521 located on one side of the Y-axis and the Y-axis is not equal to the distance between the center of the pin shaft connecting hole 1521 located on the other side of the Y-axis and the Y-axis; wherein, the X-axis is an axis passing through the center axis of rotation and parallel to the extension direction of the tower crane boom section, and the Y-axis is an axis passing through the center axis of rotation and perpendicular to the X-axis.

[0053] Figure 3 for Figure 1 The top view of the rotary assembly in FIG. Figure 3As shown, specifically, the upper support 100 includes four box-type mounting ears 150. On the one hand, the box-type mounting ears 150 are arranged symmetrically with respect to the X-axis, and on the other hand, the box-type mounting ears 150 are arranged asymmetrically with respect to the Y-axis. In other words, in this embodiment, the box-type mounting ears 150 are arranged asymmetrically in the extension direction of the tower crane boom section. Such an arrangement compensates for the vertical force difference generated by the upper parts (such as balance arms, lifting arms, etc.) installed above the slewing assembly, so that the bending moments generated by the upper parts connected on both sides of the Y-axis are close, which is conducive to a more uniform distribution of the overall stress of the slewing assembly. Preferably, the distance between the center of the pin connection hole 1521 on one side of the Y-axis and the Y-axis is 1150mm to 1200mm; the distance between the center of the pin connection hole 1521 on the other side of the Y-axis and the Y-axis is 1300mm to 1350mm.

[0054] like Figure 3 As shown, in the illustrated embodiment, the distance between the box-type mounting ear seat 150 close to the motor mounting seat 170 and the Y axis is L1, and the value range of L1 is 1150mm~1200mm. The distance between the box-type mounting ear seat 150 away from the motor mounting seat 170 and the Y axis is L2, and the value range of L2 is 1300mm~1350mm.

[0055] In an embodiment of the invention, the lower support 300 further includes a plurality of lifting support structures 320 evenly spaced along the circumference. The lifting support structures 320 include diagonal bracing angle steels 321 for increasing connection strength.

[0056] Specifically, during the process of lifting and adding sections to the tower crane, the lifting power device acts on the lifting support structure 320 to lift the slewing assembly and the upper part. Therefore, the structural strength of the lifting support structure 320 is ensured to ensure safety during the process of lifting and adding sections to the tower crane. The existing lifting support structure uses a box-type structure assembled from multiple flat plates as a diagonal brace to ensure structural strength. The slewing assembly of the present invention has better mechanical properties and is lighter in weight. In this embodiment, the use of diagonal bracing angle steel 321 as a diagonal brace can ensure that the jacking support structure 320 has sufficient strength to withstand the jacking load, and also reduces the weight of the slewing assembly.

[0057] While ensuring the structural strength of the jacking support structure 320, it is also necessary to avoid the entire rotary assembly from occupying too much space to facilitate transportation. Figure 2 As shown, in the illustrated embodiment, the included angle between the diagonal bracing angle steel 321 and the horizontal plane is a, and the value range of a is 75° to 83°.

[0058] In the embodiment of the present invention, a speed sensor 160 for detecting the working condition of the slewing bearing 200 is further provided in the upper support 100 .

[0059] like Figure 2As shown, in the rotary assembly, a gear ring transmission mechanism is used to enable the upper support 100 to rotate, and the speed sensor 160 can sense the rotation of the gear ring transmission mechanism to generate a pulse signal.

[0060] In an embodiment of the present invention, a tower crane is further provided. The tower crane includes the above-mentioned slewing assembly. Therefore, it is obvious that the tower crane has all the beneficial effects brought about by the above-mentioned slewing assembly, which will not be described in detail here.

[0061] It is understood that the tower crane may include other components independent of or interacting with the slewing assembly, such as a control system. In an optional embodiment, the control system can obtain pulse signals transmitted by the speed sensor 160 and determine slewing stability based on the stability of the pulse signals. This can be used to indicate when maintenance is required for the slewing support bearing 200 and the drive motor 400, thereby improving the reliability and maintainability of the entire machine.

[0062] The above describes in detail the optional implementation methods of the embodiments of the present invention in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation methods. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the scope of protection of the embodiments of the present invention.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will no longer separately describe various possible combinations.

[0064] In addition, various implementations of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A slewing assembly for a tower crane, characterized in that: The rotary assembly comprises: A slewing bearing (200) comprising a slewing raceway; an upper support (100) pivotally connected to the upper side of the slewing bearing (200) and comprising an upper support barrel (110); and A lower support (300) connected below the slewing bearing (200) and comprising a lower support barrel (310); The rotary raceway, the upper support barrel (110), and the lower support barrel (310) are coaxially arranged and have the same radius; The upper support (100) further includes an upper support lower cover plate (130), the upper support lower cover plate (130) being arranged at the bottom end of the upper support barrel (110) and connected to the slewing bearing (200), the upper support lower cover plate (130) including a circumferential skirt (131), the circumferential skirt (131) extending outward from the upper support barrel (110) in the circumferential direction and being connected to the outer ring of the slewing bearing (200) via a threaded connection; The inner ring of the slewing bearing (200) is a gear ring and is fixedly connected to the lower support (300); the outer ring of the slewing bearing (200) is connected to the upper support (100); a motor mounting seat (170) is provided in the upper support (100); a driving motor (400) is provided on the motor mounting seat (170); and a gear meshing with the gear ring is pivotally connected to the output shaft of the driving motor (400).

2. The slewing assembly for a tower crane according to claim 1, characterized in that: The upper support (100) further comprises: An upper support cover plate (120) is provided on the top end of the upper support surrounding barrel (110); an intermediate support plate (140) extending outwardly from the upper support barrel (110) along the circumferential direction and arranged spaced apart from the upper support upper cover plate (120) and the upper support lower cover plate (130); and A box-shaped mounting ear seat (150) has a bottom end connected to the intermediate support plate (140) and a top end extending upward and beyond the upper support cover plate (120).

3. The slewing assembly for a tower crane according to claim 2, characterized in that: The distance between the intermediate support plate (140) and the upper support upper cover plate (120) and the distance between the intermediate support plate (140) and the upper support lower cover plate (130) are both 400 mm to 600 mm.

4. The slewing assembly for a tower crane according to claim 2, characterized in that: The box-type mounting lug seat (150) comprises: a box-shaped fixing portion (151) connected between the upper support cover plate (120) and the intermediate support plate (140) and connected to the upper support barrel (110); and The ear seat connecting portion (152) extends upward from the top end of the box-shaped fixing portion (151) and is provided with a pin connecting hole (1521).

5. The slewing assembly for a tower crane according to claim 4, characterized in that: The ear seat connecting portion (152) is also provided with an ear hole (1522).

6. The slewing assembly for a tower crane according to claim 4, characterized in that: The upper support (100) is provided with two box-shaped mounting ears (150) on both sides of the Y axis, the two box-shaped mounting ears (150) on one side of the Y axis are symmetrically arranged relative to the X axis, the box-shaped mounting ears (150) on one side of the X axis are equidistant from the X axis, and the distance between the center of the pin connection hole (1521) on one side of the Y axis and the Y axis is unequal to the distance between the center of the pin connection hole (1521) on the other side of the Y axis and the Y axis; The X-axis is an axis passing through the rotation center axis and arranged parallel to the extension direction of the tower crane boom section, and the Y-axis is an axis passing through the rotation center axis and arranged perpendicular to the X-axis.

7. The slewing assembly for a tower crane according to claim 6, characterized in that: The distance between the center of the pin connection hole (1521) located on one side of the Y-axis and the Y-axis is 1150mm~1200mm; the distance between the center of the pin connection hole (1521) located on the other side of the Y-axis and the Y-axis is 1300mm~1350mm.

8. The slewing assembly for a tower crane according to claim 1, characterized in that: The lower support (300) further comprises a plurality of lifting support structures (320) arranged at even intervals along the circumferential direction, wherein the lifting support structures (320) comprise diagonal bracing angle steels (321) for enhancing connection strength.

9. The slewing assembly for a tower crane according to claim 8, characterized in that: The included angle between the diagonal bracing angle steel (321) and the horizontal plane is 75° to 83°.

10. The slewing assembly for a tower crane according to any one of claims 1 to 9, characterized in that: A speed sensor (160) for detecting the working condition of the slewing bearing (200) is also provided in the upper support (100).

11. A tower crane, characterized in that: The tower crane includes the slewing assembly according to any one of claims 1 to 10.

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