Carrier Frames and Mobile Cranes

Abstract

To realize a structure that is lightweight and prevents torsion, deflection, stress and the like of a carrier frame, which may occur at the time of lifting operation.SOLUTION: A carrier frame for mounting a turning mechanism, has: a ring plate at an upper portion on which the turning mechanism is mounted; and ribs at a lower portion in the vicinity the ring plate. The ribs are each obliquely disposed such that a lower portion is separated outward from the ring plat and at least an upper portion is fixed obliquely to a side plate.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a carrier frame used in a mobile crane or the like. [Background technology]

[0002] In mobile cranes and other devices, a ring plate on which the slewing mechanism is mounted is installed near the center of the carrier frame. The slewing mechanism, which carries a heavy load, rotates on the ring plate. The ring plate has some areas that are heavily loaded and some areas that are not. For example, in the case of a mobile crane, when a heavy load is applied to the tip of the boom during a lifting operation, a large force is applied to the ring plate in the direction that lowers the tip of the boom. Furthermore, when the boom is stowed, a counterweight, such as a winch, applies a force to the ring plate in the opposite direction. In this way, the force applied to the ring plate tends to deflect the carrier frame. To support this load, a rib can be provided below the ring plate. Patent Document 1 discloses a rib called a cross member provided below the ring plate to support the load and prevent deformation of the top panel of the carrier frame. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 57-134975 Summary of the Invention [Problem to be solved by the invention]

[0004] The ribs in Patent Document 1 are installed vertically and are thought to receive loads in the vertical direction. These ribs also suppress deflection of the carrier frame. Furthermore, it is conceivable to install ribs at a position away from the ring plate to prevent deflection of the carrier frame. The ribs contribute to reducing the weight of the carrier frame. However, in order to keep the twisting, deflection, stress, etc. of the carrier frame that occur during lifting operations within target values, the plate thickness of the ribs needs to be increased to a certain extent. Therefore, it is difficult to further reduce the weight of the carrier frame. The objective of the present invention is to realize a lightweight structure that suppresses the twisting, deflection, stress, etc. of the carrier frame that occur during lifting operations. [Means for solving the problem]

[0005] The carrier frame according to one embodiment of the present invention is a carrier frame for mounting a swivel mechanism, and has a ring plate on an upper portion on which the swivel mechanism is mounted, and a lower portion near the ring plate. Curved plate inclination having ribs, curved plate slope The rib is characterized in that its lower portion is disposed obliquely away from the outside of the ring plate, and at least its upper portion is fixed obliquely to the side plate. [Effects of the Invention]

[0006] According to the present invention, the force acting on the ring plate during lifting operations can be efficiently distributed to the entire carrier frame, thereby making it possible to reduce the weight of the carrier frame. [Brief explanation of the drawings]

[0007] [Figure 1] Side view of a mobile crane. [Figure 2] Top view of a mobile crane. [Figure 3] FIG. [Figure 4] FIG. 1 is a perspective view of a conventional ring plate and rib. [Figure 5] FIG. 1 is a side view of a conventional ring plate and rib. [Figure 6] FIG. 4 is a perspective view of a ring plate and a rib according to the embodiment. [Figure 7] FIG. 4 is a side view of a ring plate and a rib according to an embodiment. [Figure 8] 10 is a graph showing the inclination angle of the ring plate relative to the turning angle. DETAILED DESCRIPTION OF THE INVENTION

[0008] In this application, the horizontal direction and the vertical direction are defined as the horizontal direction and the vertical direction when a mobile crane or the like is placed on a horizontal surface.

[0009] FIG. 1 shows a side view of a mobile crane C equipped with a carrier frame 1 according to an embodiment of the present invention or a conventional carrier frame 4. Carrier frames 1 and 4 are carrier frames for mounting a slewing mechanism. The mobile crane C in FIG. 1 is in a travelable state, with a boom 21 tilted forward on the upper slewing unit 2. A winch (hidden by the exterior in FIG. 1) and a hydraulic hose reel 22 are provided behind the slewing unit 2, which is the slewing mechanism. The slewing unit 2 is mounted on ring plates 17 and 47 shown in FIG. 3 and elsewhere so that it can rotate horizontally. Carrier frame 4 is the same as carrier frame 1 shown in FIG. 3 except for the configuration of the ribs provided inside. Because the appearance of carrier frame 4 is the same as carrier frame 1, the reference numeral for carrier frame 4 is also shown in FIGS. 1 and 3.

[0010] During lifting operations, the outriggers of the mobile crane C are deployed to stabilize the mobile crane C. Figure 2 shows a top view of the mobile crane C with the outriggers 3 deployed. During lifting operations, the arms 31 of the outriggers 3 are extended sideways at the front and rear of the carrier frames 1 and 4. The lower parts of the jack posts 32 extending downward from the tips of the arms 31 are pressed against the ground to secure the carrier frames 1 and 4. The load of the swivel unit 2 is supported by the ring plates 17 and 47, but the force applied to the tip of the boom 21 during lifting operations biases the load on the ring plates 17 and 47. When the boom 21 rotates due to the rotation of the swivel unit 2, the position on the ring plates 17 and 47 that receives the larger load changes. The outriggers 3 are located at the front and rear ends of the carrier frame 1. As the load of the swivel unit 2 is transferred from the ring plates 17 and 47 to the outriggers 3, stress is generated in the carrier frames 1 and 4, causing twisting and bending. The carrier frame must be designed to keep the twisting and bending that occurs at this time below the design value.

[0011] Figure 3 shows a perspective view of carrier frames 1 and 4 used in mobile crane C. In Figure 3, arrows indicate the front, back, left, right, and top and bottom of mobile crane C. Carrier frames 1 and 4 are constructed with two outer plates 13 and 43 connecting the sides of upper plates 11 and 41 and the sides of lower plates 12 and 42. Two inner plates 14 and 44 are provided inside the carrier frames 1 and 4, parallel to the outer plates 13 and 43. The outer plates 13 and 43 and the inner plates 14 and 44 are side plates.

[0012] A ring plate 17, 47 is provided approximately in the center of the top plate 11, 41. The top plate 11, 41 is angled upward to form top surface inclined portions 114, 414 and top surface inclined portions 115, 415 on the front and rear sides of the ring plate 17, 47. As a result, the top plate 11, 41 is slightly lower near the ring plate 17, 47, forming top surface low portions 111, 411. In this embodiment and the conventional example, the top surface low portions 111, 411 extend horizontally. At positions forward away from the ring plate 17, 47, the top plate 11, 41 is higher than the top surface low portions 111, 411, forming top surface high portions 112, 412. Furthermore, the top plate 11, 41 is higher than the top surface low portions 111, 411 at positions rearward away from the ring plate 17, 47, forming top surface high portions 113, 413. In this embodiment and the conventional example, the upper surface high portions 112, 412 and the upper surface high portions 113, 413 also extend horizontally, similar to the upper surface low portions 111, 411. The upper surface high portions 112, 412 and the upper surface high portions 113, 413 are located at the same height. The upper surface low portions 111, 411 and the front upper surface high portions 112, 412 are connected by inclined upper surface inclined portions 114, 414, and the upper surface low portions 111, 411 and the rear upper surface high portions 113, 413 are connected by inclined upper surface inclined portions 115, 415.

[0013] Similarly, the lower plates 12, 42 also have lower surface inclined portions 124, 424 and 125, 425 at their front and rear sides below the ring plates 17, 47, respectively. The lower plates 12, 42 have lower surface low portions 121, 421 that are low near the approximate center. In this embodiment and the conventional example, the lower surface low portions 121, 421 also extend horizontally, similar to the upper surface low portions 111, 411, etc. The lower plates 12, 42 are higher than the lower surface low portions 121, 421 at positions forward away from the ring plates 17, 47, forming lower surface high portions 122, 422. The lower plates 12, 42 are higher than the lower surface low portions 121, 421 at positions rearward away from the ring plates 17, 47, forming lower surface high portions 123, 423. The lower surface high portions 122, 422 and the lower surface high portions 123, 423 also extend horizontally, similar to the lower surface low portions 121, 421, etc. The lower surface low portions 121, 421 and the front lower surface high portions 122, 422 are connected by inclined lower surface inclined portions 124, 424, and the lower surface low portions 121, 421 and the rear lower surface high portions 123, 423 are connected by inclined lower surface inclined portions 125, 425.

[0014] 3, in the carrier frames 1 and 4, the vicinity of the ring plates 17 and 47 sandwiched between the upper surface lower portion 111 and the lower surface lower portion 121 forms thick frame portions 1a and 4a that are thick in the vertical direction. The front sides of the thick frame portions 1a and 4a form thin frame portions 1b and 4b that are thin in the vertical direction via connecting portions 1d and 4d. The rear sides of the thick frame portions 1a and 4a form thin frame portions 1c and 4c that are thin in the vertical direction via connecting portions 1e and 4e.

[0015] On the inside of the ring plates 17, 47, the upper plates 11, 41 are open, forming inner-ring openings 18, 48. The inner-ring openings 18, 48 house swivel joints and the like for transmitting hydraulic pressure and electricity to the rotating section 2. In the thin frame sections 1c, 4c at the rear of the ring plates 17, 47, the upper plates 11, 41 and the lower plates 12, 42 are open above and inside the inner plates 14, 44, forming rear openings 116, 416. An engine (not shown) is mounted in the rear openings 116, 416.

[0016] The arms 31 of the outrigger 3 are stored in the outrigger installation holes 19, 49 provided near the front and rear ends of the carrier frames 1, 4. When using the outrigger 3, the arms 31 are pulled out to the left and right of the carrier frames 1, 4 as shown in Figure 2, and the lower ends of the jack posts 32 located at the tips of the arms 31 are pressed against the ground with a jack. In this way, the carrier frames 1, 4 are fixed to the ground at a total of four points: two points at the front and two points at the rear of the mobile crane C.

[0017] A plurality of ribs are provided on the inside of the carrier frame. FIG. 4 shows a perspective view of a ring plate 47 and ribs near the ring plate 47 for a conventional carrier frame 4 in which ribs are provided vertically. FIG. 5 shows a side view of the ring plate 47 and ribs near the ring plate 47 for a conventional carrier frame 4 in which ribs are provided vertically. The conventional carrier frame 4 in FIGS. 4 and 5 has a vertical rib structure. To make the configuration easier to see, the upper plate 41, lower plate 42, outer plate 43, and inner plate 44 are omitted from FIG. 4. The outer plate 43 and inner plate 44 are also omitted from FIG. 5. In FIG. 5, the fixed portions of the ribs to the outer plate 43 are indicated by bold lines.

[0018] As shown in Figures 4 and 5, cylindrical vertical ribs 45, namely curved vertical ribs 451 and curved vertical ribs 452, are provided below the ring plate 47 at two locations, one at the front and one at the rear, along the curve of the ring plate 47. The upper ends of the curved vertical ribs 451 and 452 are located below the ring plate 47 and form an arc shape. The outer plate 43 protrudes outward near the ring plate 47. The curved vertical ribs 451 and 452 are perpendicular to the upper surface low portion 411 and the lower surface low portion 421. In Figure 5, the curved vertical ribs 451 and 452 protrude from the upper portion of the outer plate 43 in the left-right direction, so the thick lines that are fixed to the outer plate 43 are oblique. The outer sides of the vertical ribs 45 are welded to the outer plate 43.

[0019] Additionally, flat vertical ribs 45 are provided at four locations between the curved vertical ribs 451 and the curved vertical ribs 452 under the upper panel 41 inside the ring plate 47. Flat vertical ribs 453 are provided at two locations on the front left and right, and flat vertical ribs 454 are provided at two locations on the rear left and right. The flat vertical ribs 453 and 454 have their upper portions extended outward as shown in FIG. 4 because the upper portion of the outer panel 43 protrudes in the left and right directions. Furthermore, flat vertical ribs 455 and 456, which are flat vertical ribs 45, are provided at two locations forward of the ring plate 47, and flat vertical ribs 457, 458, and 459, which are flat vertical ribs 45, are provided at three locations rearward of the ring plate 47. The flat vertical ribs 459 are provided separately on the left and right. All of the ribs on the carrier frame 4 are formed by the vertical ribs 45.

[0020] The ribs of the carrier frame 1 according to an embodiment of the present invention are shown in Figures 6 and 7. Figure 6 is a perspective view of the vicinity of the ring plate 17, and Figure 7 is a side view of the vicinity of the ring plate 17. To make the configuration easier to see, the upper plate 11, lower plate 12, outer plate 13, and inner plate 14 are omitted from Figure 6. Also, the outer plate 13 and inner plate 14 are omitted from Figure 5. The carrier frame 1 shown in Figures 6 and 7 has an inclined rib structure with inclined ribs 16. The inclined ribs 16 are ribs that are arranged at an angle so that their lower portions are away from the outside of the ring plate 17.

[0021] Cylindrical vertical ribs 15 are provided below the ring plate 17 at two locations, the front and the rear, along the curve of the ring plate 17. A curved vertical rib 151 is provided at the front, and a curved vertical rib 152 is provided at the rear. The upper ends of the curved vertical ribs 151 and 152 are located along the bottom of the ring plate 17 and form an arc. In addition, flat vertical ribs 153, which are flat vertical ribs 15, are provided at two locations, left and right, between the curved vertical ribs 151 and 152 below the top plate 11 on the inside of the ring plate 17. The curved vertical ribs 151 and 152 are perpendicular to the upper surface low portion 111 and the lower surface low portion 121. In Figure 7, because the upper portions of the outer plate 13 protrude in the left-right direction, the thick lines that are the fixed portions of the curved vertical ribs 151 and 152 to the outer plate 13 are oblique. Furthermore, the flat vertical rib 153 has an upper portion that expands outward because the upper portion of the outer plate 13 protrudes in the left-right direction.

[0022] In the carrier frame 1 of this embodiment, curved inclined ribs 16 are provided below the ring plate 17 at two locations, one at the front and one at the rear, with the lower portions disposed at an angle away from the outside of the ring plate 17. A curved inclined rib 161 is provided at the front, and a curved inclined rib 162 is provided at the rear. The upper ends of the curved inclined rib 161 and the curved inclined rib 162 are located along the bottom of the ring plate 17 and form an arc shape. The lower portion of the curved inclined rib 161 is located forward and fixed to the lower surface low portion 121, while the lower portion of the curved inclined rib 162 is located rear and fixed to the lower surface low portion 121. The curved inclined rib 161 is located forward of the curved vertical rib 151, and the curved inclined rib 162 is located rearward of the curved vertical rib 152.

[0023] In Figure 7, the curved plate inclined ribs 161 and 162 protrude from the upper part of the outer plate 13 in the left-right direction, so the thick diagonal lines that are the fixing points to the outer plate 13 have bent parts at the top. The curved plate inclined ribs 161 and 162 are arranged so that their curved surfaces are oblique, so they are highly strong despite their thinness. In addition, because the fixing points between the upper plate 11 and the lower plate 12 form oblique curves when viewed from above, the fixing parts are long and firmly fixed.

[0024] Furthermore, inclined ribs 16 are provided at two locations, front and rear, at positions spaced apart from the ring plate 17 in the front-rear direction. The inclined ribs 16 are arranged diagonally from the top plate 11 toward the outside of the ring plate 17. Figures 6 and 7 show the front flat inclined rib 163 and the rear flat inclined rib 164. The flat inclined rib 163 is fixed to the connection between the top surface low portion 111 and the top surface inclined portion 114. The flat inclined rib 164 is fixed to the connection between the top surface low portion 111 and the top surface inclined portion 115. This structure also efficiently distributes stress applied to the connection portions. The flat inclined rib 163 is fixed to the bottom surface inclined portion 124 at a substantially right angle, and the flat inclined rib 164 is fixed to the bottom surface inclined portion 125 at a substantially right angle. This allows the lower portions of the flat inclined ribs 163 and 164 to firmly receive the force even if the ring plate 17 attempts to tilt. Furthermore, the flat inclined rib 163 is inclined in the same direction as the curved inclined rib 161, and the flat inclined rib 164 is inclined in the same direction as the curved inclined rib 162. This allows the flat inclined ribs 163 and 164 to be arranged inside the carrier frame 1 so as to avoid the curved inclined ribs 161 and 162.

[0025] A flat vertical rib 154, which is also a vertical rib 15, is provided in front of the front flat inclined rib 163. Furthermore, a flat vertical rib 155, which is also a vertical rib 15, is provided behind the rear flat inclined rib 164. The flat vertical rib 154 connects the upper surface high portion 112 and the lower surface high portion 122, and the flat vertical rib 155 connects the upper surface high portion 113 and the lower surface high portion 123. In this way, the inclined rib structure of this embodiment also includes vertical ribs.

[0026] The outer sides of the vertical ribs 15 and the inclined ribs 16 are welded and fixed to the outer plate 13. In Fig. 7, the fixed parts to the outer plate 13 are indicated by bold lines. The curved plate inclined ribs 161 and the curved plate inclined ribs 162 have a shape in which a part of the side of a truncated cone is cut away, with the inside of the ring plate 17 as the upper surface.

[0027] We simulated the inclination angle of the ring plates 17, 47 relative to the rotation angle of the rotating section 2 for the conventional vertical rib structure shown in Figures 4 and 5 and the inclined rib structure according to the embodiment of the present invention shown in Figures 6 and 7. Figure 8 shows the results. The horizontal axis of Figure 8 represents the rotation angle θ of the rotating section, and the vertical axis represents the inclination angle φ of the ring plates 17, 47. A mobile crane C is installed using the outriggers 3 to keep the ring plates 17, 47 horizontal, and a lifting operation is performed. The inclination angle φ occurs due to the load on the ring plates 17, 47. The more unevenly the load is applied to the ring plates 17, 47, the larger the inclination angle φ. Regarding the rotation angle θ, 0° represents when the boom 21 faces forward, and 180° represents when the boom 21 faces backward. The inclination angle φ represents the inclination angle toward the boom 21. The dotted lines represent the carrier frame 4 with the conventional vertical rib structure shown in Figures 4 and 5, and the solid lines represent the carrier frame 1 with the inclined rib structure according to the embodiment of the present invention shown in Figures 6 and 7. In both the conventional example and the embodiment of the present invention, the tilt angle φ is minimum when the boom is facing forward at 0° and when facing backward at 180°.

[0028] In the carrier frame 4 with a vertical rib structure shown by the dotted line, the inclination angle φ is maximum when the rotation angle θ is near 60° and 300°. On the other hand, in the carrier frame 1 with an inclined rib structure, as shown by the solid line, the inclination angle φ, which is maximum when the rotation angle θ is near 60° and 300°, is suppressed. In this way, the use of an inclined rib structure suppresses twisting and bending due to stress in the carrier frame that occurs during lifting operations. Furthermore, because the inclined rib structure efficiently distributes the force acting on the ring plate during lifting operations throughout the entire carrier frame, the plate material that makes up the carrier frame can be made thinner and lighter.

[0029] The inclined ribs 16 are fixed to the outer plate 13 and the inner plate 14 in an oblique direction, moving further forward or backward from the ring plate 17 as they go downward. It is believed that the inclined ribs 16, particularly at the upper part, being fixed to the outer plate 13 and the inner plate 14, contribute greatly to preventing the ring plate 17 from tilting.

[0030] The curved inclined ribs 161, 162 and the flat inclined ribs 163, 164 are both inclined ribs 16 inclined with respect to the vertical direction. The inclination of the inclined ribs 16 is preferably 15° to 45° with respect to the vertical direction, and more preferably 25° to 35°. Furthermore, the curved inclined ribs 161, 162 in the embodiment have a shape obtained by cutting out a portion of a truncated cone, with the upper surface being a circular plate including the underside of the ring plate 17. However, the curved inclined ribs may be any shape as long as they are curved plates, such as a shape obtained by cutting out a portion of a tilted cylinder. Furthermore, the upper end of the curved inclined rib does not have to be below the ring plate. For example, the curved inclined rib may be fixed to the upper plate at a position separated from the ring plate in the front-to-rear direction, as with the flat inclined ribs 163, 164, and may further extend diagonally downward in the front-to-rear direction.

[0031] The present invention can also be used for carrier frames other than mobile cranes, as long as the carrier frame has a swivel mechanism. For example, the present invention can be used for carrier frames of power shovels, etc.

[0032] In addition, the specific configuration is not limited to the embodiments, and the present invention includes design changes within the scope of the gist of the present invention. Furthermore, the above-mentioned embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0033] C. Mobile crane 1 Carrier Frame 11 Top plate 111 Lower part of top surface 112 Upper surface high part 113 Upper surface high part 114 Upper slope part 115 Top slope 116 Rear opening 12 Bottom plate 121 Lower part 122 Lower surface high part 123 Lower surface high part 124 Bottom inclined part 125 Bottom inclined part 13 Outer plate 14 Inner plate 15 vertical ribs 151 Curved Plate Vertical Rib 152 Curved Plate Vertical Rib 153 Flat Plate Vertical Rib 154 Flat Plate Vertical Rib 155 Flat Plate Vertical Rib 16 Inclined Rib 161 Curved plate inclined rib 162 Curved plate inclined rib 163 Flat plate inclined rib 164 Flat Plate Inclined Rib 17 Ring Plate 18 Ring inner opening 19 Outrigger installation port 1a Thick frame part 1b Thin frame part 1c Thin frame part 1d Connection 1e Connection 2 Swivel section 21 Boom 22 Hydraulic hose reel 3 Outrigger 31 Arm 32 Jack Post 4 Carrier Frame 41 Top plate 411 Lower part of top surface 412 Upper surface high part 413 Upper surface high part 414 Upper slope part 415 Top slope 416 Rear opening 42 Bottom plate 421 Lower part 422 Lower surface high part 423 Lower surface high part 424 Bottom inclined part 425 Bottom inclined part 43 Outer plate 44 Inner plate 45 vertical rib 451 Curved Plate Vertical Rib 452 Curved Plate Vertical Rib 453 Flat Plate Vertical Rib 454 Flat Plate Vertical Rib 455 Flat Plate Vertical Rib 456 Flat Plate Vertical Rib 457 Flat Plate Vertical Rib 458 Flat Plate Vertical Rib 459 Flat Plate Vertical Rib 47 Ring Plate 48 Ring inner opening 49 Outrigger installation port 4a Thick frame part 4b Thin frame part 4c Thin frame part 4d Connection 4e Connection

Claims

1. A carrier frame for mounting a turning mechanism, A ring plate on which the rotation mechanism is placed is provided at the top. A curved plate inclined rib is provided below the ring plate in the vicinity thereof, The curved plate inclined rib is disposed at an angle so that its lower portion is spaced away from the outside of the ring plate, and at least its upper portion is fixed at an angle to the side plate.

2. A carrier frame as described in claim 1, characterized in that the upper end of the curved inclined rib is located below the ring plate along the ring plate.

3. A carrier frame as described in claim 2, characterized in that a flat inclined rib made of a flat plate arranged diagonally from the upper plate of the carrier frame is provided outside the curved inclined rib.

4. A mobile crane comprising the carrier frame according to any one of claims 1 to 3.

Images