Rail joint

Abstract

To provide a rail that extends the operational life of a crane rail by reducing the wear rate in high stress areas at the joints and adding additional wear material above the rail at the joints. SOLUTION: A rail (13) supporting a trolley (14) of a gantry crane (10) has rail sections (18, 19) on opposite sides of a joint (17) with an end region (20) of a modified rail head profile that guides the wheels of the trolley (14) onto a ridge (23) that gradually exceeds the height (L1) of the rail head (27) as it approaches the joint (17). The ridge (23) then carries the wheels to the joint (17) where the transition from one rail section to the next takes place on a reinforced region. The load-bearing apex (A) of the ridge is located away from the side edge of the rail (13) and the end of each lug (21).

Description

Technical Field

[0001] The present invention relates to a joint between rails for carrying a wheeled vehicle, particularly (but not limited thereto) a joint between rails installed on a gantry crane.

Background Art

[0002] Gantry cranes are widely used in dockyards and other locations for loading and unloading containerized cargo. Typically, a gantry crane comprises a large chassis, wheels for traveling along a first axis along the ground, and an elevated boom extending along a second axis perpendicular thereto. The container handled by the crane is supported by a cable suspended vertically from a trolley that moves along the longitudinal axis of the boom. Usually, this trolley is equipped with wheels that run on parallel rails fixed to the support surface of the boom.

[0003] A gantry crane handling containers in a dockyard may have a hinged boom extending across the width of the ship from the chassis of the crane. The hinged boom can be lifted to allow the ship to enter and exit without being obstructed by the dockside, and it will be understood that for this purpose it is necessary to provide a joint in the rails. Typically, such a joint is provided as a lap joint between rail sections arranged longitudinally in the hinged and non-hinged parts of the boom, with adjacent ends overlapping to provide a smooth transition to the next rail section and prevent gaps from occurring.

[0004] The elongated rails used in gantry cranes comprise a base portion disposed on the support surface and an upward central web extending between the base portion and the head portion of the rail on which the trolley travels. The upper surface of the head portion of the rail is curved upward from the edges on both sides towards the center, and the wheels of the trolley are supported by the central region of the head portion located directly above the upward web portion of the rail.

[0005] The problem with this configuration is that the ends of adjacent rail sections are cut longitudinally along this central region, with incisions extending into the web to form the respective protrusions and recesses of the lap joint. As a result, the load of the trolley, which passes over the joint 100 to 200 times a day, is distributed along the longitudinally cut upward sides of the rail sections. Consequently, impacts from the wheels cause wear and damage to one or both rail sections, leading to stress failure, where cracks propagate along the sides of the web, ultimately resulting in failure. Damage to the joint means that the rails must be replaced every 5 to 7 years, sometimes even sooner. Since the rails are usually replaced along the entire boom, this is extremely expensive and results in a prolonged downtime for the crane. [Overview of the Initiative]

[0006] Based on the above, we have devised improvements related to rail joints. According to a first aspect of the present invention, a rail is provided comprising a rail head defining an upper rail surface for supporting a wheeled vehicle and a base defining a lower rail surface for engaging with a support structure. The rail is divided by a joint into first and second rail sections, and adjacent end regions of the rail sections are provided with projections and recesses located on the opposite longitudinal sides of the first and second sections, respectively. The projections of each rail section overlap each other longitudinally when in use, with the projection of the first rail section extending into the recess of the second rail section, and vice versa. The upper rail surface in each adjacent end region is cut along one side edge by the recess and has a modified profile compared to the profile at a location away from that end region. The modified profile of the upper rail surface in each adjacent end region includes an elongated ridge section extending longitudinally along the projection, the apex of which is located away from the side edge from which the upper rail surface is cut by the recess.

[0007] Joints may be formed between rail sections extending along the inner and outer ends of the gantry crane boom, respectively. These joints allow one rail section to rotate upward relative to the other rail section between its longitudinally aligned position during use and its deflected position. Alternatively, the joint may be an expansion joint formed between permanently longitudinally aligned rail sections.

[0008] The present invention solves the aforementioned problem because the load when a trolley or other vehicle passes through the joint is borne along the elongated ridge section of the protruding outer end portion, which is located away from the side edge cut off by the recess on the upper rail surface. Thus, the force on the recess side of the rail is greatly reduced, and as a result, the risk of wear or damage to one or both rail sections from the impact of the wheels is reduced.

[0009] The apex of each elongated ridge section may be located away from both the longitudinal lateral edge opposite the projection on which it is provided. Each elongated ridge section may extend along the center of the projection on which it is provided.

[0010] In adjacent end regions of a rail section, projections may extend from their respective inner ends, and elongated ridge sections may extend from these projections to their inner ends within each end region. In this way, the load when a trolley or other vehicle passes through the joint is borne by the elongated ridge sections both before and after passing through the joint.

[0011] Each inner end may further contain a shorter ridge section that extends parallel to the elongated ridge section toward the rivet. When in use, each member's short ridge section extends so as to connect end-to-end with the elongated ridge sections of other members.

[0012] It is understood that the support web portion at the protruding outer end of a known joint is thinned by at least 50% in the portion cut to form the recess of the lap joint. Consequently, the protruding outer end of the rail section is weakened, which further exacerbates the risk of joint failure. To address this issue, the opposite side of the rail at the joint includes a reinforcing material extending between the head and base portions of the rail. This lateral material increases the cross-sectional area of ​​the rail between the base and head portions, thereby strengthening the protruding outer end of the rail.

[0013] The reinforcing material may nearly close the recess that extends longitudinally along each side of the rail away from the joint.

[0014] The reinforcing materials may include reinforcing members that are bolted or otherwise secured along the opposite side of the rail at the joint.

[0015] When trolleys or other vehicles pass over joints, wear on the upper surface of the rail is unavoidable. To extend the durability and increase the strength of the joints, the apex of each ridge section may be designed so that a significant portion extends above the upper surface of the rail away from the end area. Increasing the height of the ridge section allows it to withstand more wear and also strengthens the joint.

[0016] The ends of the ridge formed by the ridge section can be tapered downward toward the upper surface of the rail away from the end region, thereby preventing abrupt changes in the rail level.

[0017] In one embodiment, the end region of each rail section is formed integrally with the elongated rail member, for example, by machining or casting the end of the rail member into a predetermined shape.

[0018] In another embodiment, each rail section includes a short rail end member and elongated rail members positioned at both ends, and the end region of each rail section is formed integrally with the rail end member, for example by machining or casting the end of the rail end member into a predetermined shape.

[0019] It will be understood that it is far simpler to form the ends of short rail members into the desired shape, and that existing rails can be repaired relatively easily by cutting off the length of rail adjacent to the joint and attaching the short rail end members.

[0020] In another embodiment, each elongated ridge section is mounted on a capping member that is attached, for example, to a complementary formation provided at the end region of each rail section, either by bolting or welding.

[0021] In one embodiment, complementary parts of each rail section are formed integrally with the elongated rail member, for example, by machining or casting the end of the rail member into a predetermined shape.

[0022] In another embodiment, each rail section includes a short rail end member and an elongated rail member positioned at both ends, and the complementary forming of each rail section is formed integrally with the rail end member, for example, by machining or casting the end of the rail end member into a predetermined shape.

[0023] Each capping member may also include shorter ridge sections extending parallel to a more elongated ridge section, so that when in use, the shorter ridge sections of each member connect end-to-end with the elongated ridge sections of other members.

[0024] The notch may extend from between the parallel ridge sections of each capping member to one end of the capping member, and the rail section includes fingers that extend into the notch and serve to determine the position of the capping member. In this embodiment, the opposite ends of the ridge provided by the ridge section may taper downward toward a point below the upper surface of the finger.

[0025] Also, when viewed from a second aspect of the present invention, a rail section for forming a rail as described above is provided.

[0026] Furthermore, when viewed from a third aspect of the present invention, as described above, a gantry crane is provided in which the rail sections of each rail are respectively provided on the opposite side of the hinge between the boom and the crane chassis.

[0027] Furthermore, when viewed from a fourth aspect of the present invention, a method of forming a rail as described above is provided, the method including attaching respective rail sections on opposite sides of a joint between two support structures.

[0028] In one embodiment, each rail section is formed by laying an elongated rail member and short rail end members arranged end to end. A portion of the elongated rail member may be cut away and the short rail end member laid in its place.

[0029] In another embodiment, the capping member is fixed, for example, in place by bolts or welding to complementary formations provided in the end regions of the respective rail sections.

[0030] The complementary formations may be formed by machining or casting the end regions of the rail sections.

[0031] Hereinafter, embodiments of the present invention will be described by way of example only with reference to the drawings.

Brief Description of the Drawings

[0032] [Figure 1] This is a side view of a gantry crane incorporating an embodiment of the rail according to the present invention. [Figure 2A] This is a top-down perspective view of one side of a section of rails on the gantry crane shown in Figure 1. [Figure 2B] This is an enlarged view of the end region of the rail section in Figure 2A. [Figure 3] This is a top-down perspective view from one side of the joint between the rail sections of the gantry crane shown in Figure 1. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 2A. [Figure 5] This is a cross-sectional view along line VV in Figure 2A. [Figure 6] Figures 6A and 6B are an explosion and assembly view of the outer end of a rail section of an alternative embodiment of the rail according to the present invention. [Figure 7] This is a plan view of the outer end region of a rail section of an alternative embodiment of the rail according to the present invention. [Figure 8] This is a perspective view from below, looking from one side at the proximal end of a rail end member of an alternative embodiment of the rail according to the present invention. [Modes for carrying out the invention]

[0033] Referring to Figure 1, a typical gantry crane 10 is shown, which includes a large chassis 11 on which wheels travel along rails fixed to the ground (e.g., dockside D) along a first axle. The gantry crane 10 includes an elevated boom 12 extending along a second axis perpendicular to the first axle. Containers handled by the gantry crane 10 (e.g., C) are supported by cables suspended vertically from a trolley 14 that moves along the longitudinal axis of the boom 12.

[0034] The trolley 14 is equipped with wheels that run on the upper surface of a steel rail 13. The rail 13 is fixed to the support surface of the boom 12 on its underside, for example, using clips disclosed in our pending patent application GB2591259. The boom 12 of the gantry crane 10 is rotatable at point P, and by raising the outer end of the boom 12, ships can enter and exit the dockside D without obstruction. A joint is provided at point P in the rail 13 to allow the boom 12 of the gantry crane 10 to be raised and lowered as desired, as described below.

[0035] Referring to Figures 2 to 5, each rail 13 is divided by a joint 17 into first and second rail sections 18 and 19, respectively, which extend along the inner and outer ends of the boom 12. The joint 17 allows the second rail section 19 to rotate between a position longitudinally aligned with the first rail section 18 and a raised position when in use.

[0036] Each rail section 18, 19 extends from the joint 17 and includes an elongated rail member 32 and short rail end members 31 attached to the ends. Each rail end member 31 includes an end region 20 with a modified cross-sectional shape formed by machining or casting to a predetermined shape. It will be understood that the rails 13 of a traditional gantry crane can be modified by cutting off the end section of the elongated rail on the opposite side of the joint and attaching the rail end members 31 in place. The elongated rail member 32 has a conventional shape and includes a base portion 26 with a lower rail surface 16, a head portion 27 with an upper rail surface 15, and a web-shaped support portion 28 extending between the base portion 29 and the head portion 27. On the opposite longitudinal side of the elongated rail member 32 is a longitudinally extending recess 30.

[0037] The adjacent end regions 20 of the short rail end members 31 each include a protrusion 21 and a recess 22, which are located on opposite sides in the longitudinal direction. When the boom 12 is in the lowered (use) position, the protrusions 22 of each member 31 overlap each other longitudinally at the joint 17, with the protrusion 21 of rail section 18 extending into the recess 22 of other rail section 19, and vice versa.

[0038] The upper rail surface 15 of the end region 20 of each rail end member 31 is cut out by a recess 22 along one of its side edges 25, and has a modified profile that differs from the profile of the upper rail surface 15 over the entire rail 13 away from the end region 20. The modified profile in each adjacent end region 20 of rail sections 18, 19 includes a first elongated ridge 23 that extends longitudinally along a convex portion 21. The first elongated ridge 23 has its apex A in the center of the provided convex portion 21 and is located away from the longitudinal side edge opposite the convex portion 21.

[0039] The adjacent end regions 20 of rail sections 18 and 19 also include inner end regions 26 to which their respective protrusions 21 extend. Each inner end region 26 of rail sections 18 and 19 also includes a second ridge 24 extending parallel to the first ridge 23 toward the recess 22. When the boom 12 is in the lowered (operational) position, the second ridge 24 of each rail section (e.g., 18) extends to connect end-to-end with the first ridge 23 of the other rail section (e.g., 19).

[0040] The first ridge 23 of each end region 20 also extends along the second ridge 24 from its protrusion 21 toward the inner end 26, and the load is supported by the ridges 23, 24 before and after the trolley 14 passes through the joint 17. The apex A of each ridge 23, 24 substantially extends to a level L1 that is higher than the level L2 of the upper rail surface 15 away from the end region 20. The increased height of the ridge sections 23, 24 allows for greater abrasion resistance and strengthens the joint 17. The opposite ends of the ridges 23, 24 taper downward from level L1 toward the level L2 of the upper rail surface 15, preventing abrupt changes in the rail level 13.

[0041] The recesses 30 on the longitudinal sides of the rail 30 end just before each end region 20 of each rail end member 31, so that the ridges 23 and 24 overlap with a completely solid steel region extending to the base 29, as shown in Figure 4. This increases the cross-sectional area of ​​the rail 13 and strengthens the protrusions 21. The cross-sectional shape of the proximal end of each rail end member 31 is the same as that of the elongated rail member 32, allowing for conventional welding at point W.

[0042] During use, the load of the trolley 14 passing through the joint 17 is applied to the ridges 23, 24 over an elongated region extending along the center of the protruding end 21, where the upper rail surface 15 is located away from the inner edge cut off by the rivet 22. Thus, the force on the rivet edge 25 of the rail 13 is significantly reduced, lowering the risk of wear or damage to one or both of the rail sections 18, 19 from impacts by the trolley 14.

[0043] Referring to Figures 6A and 6B, in another embodiment, instead of forming the end regions 20 of each rail section 18, 19 integrally with the rail, the shape of each end region is modified by attaching a capping member 33. The capping member 33 is attached to a complementary formed portion 34 formed in the end region 20 of each rail section, for example, by being machined or cast into a predetermined shape and then bolted to it.

[0044] Each capping member 33 further includes an elongated first ridge 230 extending parallel to a second short ridge 240, and when the boom 12 is in the lowered (use) position, the second ridge 240 of one capping member 33 extends to connect end-to-end with the first ridge 230 of the other capping member 33.

[0045] A notch 35 extends between the first ridge 230 and the second ridge 240 at the inner end of the capping member 33, and rail sections 18, 19 include a finger 36 that extends to the notch 25 to fix the position of the proximal end of the capping member 33. A pair of sockets 37 are formed on the underside of the outer end of the capping member 33, and rail sections 18, 19 include a pair of rising tabs 38 that extend to each socket 37 to fix the position of the outer end of the capping member 33.

[0046] The use of capping members 33 allows existing joints to be repaired simply by machining a formation 34 into the existing rail. Since the recess 30 on the longitudinal side of the rail 30 extends along the entire rail, its end region 20 can be reinforced by bolting or otherwise securing a reinforcing member 39 along the opposite longitudinal side of the overlapping end region 20 of the rail 13. The reinforcing member 39 ensures that the ridges 230, 240 overlap with a full steel region extending to the base 29, thereby effectively increasing the cross-sectional area of ​​the rail 13 and reinforcing the protrusion 21. It is understood that if the capping members 33 are worn or damaged, they can be easily replaced.

[0047] Referring to Figure 7, in another embodiment, the branched proximal end of each capping member 33 is provided with an end face 50 that is keyed to the distal end face 51 of the forming portion 34 to prevent the branched end 53 from separating. The underside of each capping member 33 includes a longitudinally extending forming portion 54 that engages with a complementary forming portion (not shown) provided on the bottom surface of the forming portion 34, which helps to maintain the position of the capping member 33.

[0048] Typically, the rail section opposite the joint 17 is attached to an elongated rail pad (not shown) made of elastomer material. Previously, rail pads had to be cut to shape or shortened at the joint, which presented drawbacks to these arrangements. To solve this problem, referring to Figure 8, the height H of the short rail end member 31 of each rail section 18, 19 of the present invention is substantially equal to the combined height of the elongated rail member 32 joined to it and the rail pad laid underneath. In this method, the rail pad does not extend into the joint, and the increased height of the short rail end member 31 compensates for the height lost by the rail pad. To avoid stress on the weld W between the rail end member 31 and the elongated rail member 32, a rivet 55 is provided on the underside of the proximal end of the rail end member 31, allowing the rail pad positioned beneath the elongated rail member 32 to extend below the weld W, mitigating the risk of stress caused by the rail pad terminating directly below the weld W.

[0049] The present invention provides a rail with a unique railhead profile that contacts a joint 17, guiding the trolley wheels onto a surface that gradually exceeds the height of the railhead as they approach the joint. The wheels are then carried to the joint 17, and the transition from the next rail section (e.g., 18) to the next rail section (e.g., 19) takes place on a transition region supported by both protrusions 21. The transition region is located on the reinforced cross-section of each protrusion, and the load-bearing surfaces of the ridges are positioned away from the side edges of the rail and the ends of each protrusion 21.

[0050] The rail according to this invention has a simple structure and is relatively inexpensive, yet it can reduce the wear rate in the high-stress areas of the joint and extend the operational life of the crane boom rail by adding additional wear material on top of the rail at the joint. This invention reduces trolley vibration by guiding the wheels to a smooth, undulating rail head profile.

Claims

1. The rail comprises a rail head that forms the upper surface of the rail supporting a wheeled vehicle, a base that forms the lower surface of the rail, and a support portion that connects the rail head and the base, The rail is divided into first and second rail sections in the longitudinal direction by a joint. The adjacent end regions of the first rail section and the second rail section, and the end faces where the first rail section and the second rail section meet, are provided with a convex portion and a concave portion, respectively, wherein the convex portion is provided on one of the regions obtained by dividing the end face of the rail into two in the width direction of the rail, and the concave portion is provided on the other of the two divided regions. The protrusions of the first rail section and the second rail section overlap each other in the width direction of the rail when the rail is in use, the protrusions of the first rail section are inserted into the recesses of the second rail section, and the protrusions of the second rail section are inserted into the recesses of the first rail section. The upper surface of the rail in each adjacent end region has a different shape from the upper surface of the rail away from that end region. The upper surface of the rail in each adjacent end region includes an elongated ridge section extending along the longitudinal direction of the rail from the end surface region where the protrusion is provided. The apex of the ridge section on the upper surface of the rail is positioned away from the side of the rail in the width direction of the rail. A rail characterized by its features.

2. The apex of the ridge section on the upper surface of the rail is positioned in the width direction of the rail on the protrusion where the ridge section is provided, away from the side of the rail opposite to the side surface. The rail according to feature 1.

3. The ridge section is provided along the longitudinal direction of the rail at the central position of the protrusion on which the ridge section is provided in the width direction of the rail. The rail according to feature 2.

4. On the upper surface of the rail in the adjacent end regions of the first rail section and the second rail section, a second ridge section is provided parallel to the ridge section on the side where the recess in the width direction of the rail is provided. The second ridge section of one of the first and second rail sections is connected to the other ridge section at its end face when the rail is in use. The rail according to feature 1.

5. The rails of the first rail section and the second rail section are provided with reinforcing members on the side surfaces of the support portions. The rail according to feature 1.

6. A recess extending in the longitudinal direction of the rail is formed on the side surface of the support portion. The reinforcing member is provided within the recess, The rail according to feature 5.

7. The reinforcing member includes a reinforcing member that is bolted to the side surface of the support portion of the rail in the end region, or fixed in any other way. The rail according to feature 5.

8. The apex of the ridge section is at a height from the lower surface of the rail that is greater than the height of the rail outside the end region. The rail according to feature 1.

9. The height of the upper surface of the rail is tapered and decreases as it moves away from the ridge section in the longitudinal direction of the rail, so as it matches the height of the rail outside the end region. The rail according to feature 8.

10. The rails in the end regions of the first and second rail sections are formed integrally with the rails other than those in the first and second rail sections. The rail according to feature 1.

11. It further has a capping member, The capping member is attached to the upper surface of the rail in the end region of the first rail section and the second rail section, and the shape of the upper surface of the rail is made to match the shape of the ridge section. The rail according to feature 1.

12. A gantry crane equipped with rails according to any one of claims 1 to 11.

13. Connecting the first rail section and the second rail section of the rail according to any one of claims 1 to 11, A method characterized by the following:

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