Step device for ascending and descending

Abstract

To provide a step device for ascending and descending that allows an operator to ascend and descend easily and safely, can suppress deformation or damage even when receiving external force due to interference from the contact with a road surface, has a simple structure and is easily attachable to existing heavy machines.SOLUTION: A step device 10 for ascending and descending includes: a step section 11; a mounting plate 12; and suspension lock sections 13 fixed to the front end side and rear end side of the mounting plate 12, and is attached to a heavy machine and used for ascending and descending to an operator compartment. Under normal conditions, a support shaft 33 and a suspension bracket 32 can rotate around a circular hole in the upper part of the lock hole 44. In the time of ascending and descending, when downward external force is applied to the step section 11, the suspension bracket 32 moves downward, the support shaft 33 enters a long hole part below the lock hole 44 against a compression coil spring 35, and the rotations of the support shaft 33 and the suspension bracket 32 are locked.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a step device for ascending and descending to a cab of a heavy machine such as a carrier dump. [Background technology]

[0002] Conventionally, a configuration has been known in which a step device 71 is attached as shown in Fig. 7 to allow access to and from the cab of a heavy machine such as a carrier dump. This step device 71 is made up of a member 72 attached to the frame of the carrier dump and steps (ladders) 73, and the steps 73 are configured by mounting one or more step footrests 75 on rods 74 on both sides, which are made of rigid materials such as hard rubber.

[0003] In addition, a configuration is known in which a rotatable boarding and alighting staircase is provided near the driver's cab of a carrier dump truck or the like, and before operation begins, the boarding and alighting staircase is positioned around the crawler at an angle toward the front of the machine, and when operation begins, the boarding and alighting staircase can be moved to a retreat position where it does not hinder travel or work (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-165861 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional step device as shown in FIG. 7, the rods 74 on both sides are made of rigid materials. Therefore, when the carrier dump travels uphill or on a road surface that slopes laterally, if the bottom end of the step comes into contact with the road surface or comes into contact with a rock, fallen tree, etc. (obstacle) on the road surface, the body of the step can be deformed or damaged by external forces from the road surface or rocks, causing the step device to stop functioning or become damaged.

[0006] In order to solve this problem, a step device can be constructed like a rope ladder, with the longitudinal members on both sides made of flexible members such as ropes, chains, or other similar materials and a footrest attached between them. However, this type of step device is not necessarily preferable, as the step device may move or move away when the driver goes up or down between the cab, making it difficult to place his or her foot on the step device, and even if the driver is able to get up or down by placing his or her foot on the step device, there is a risk of falling.

[0007] The boarding and alighting stairs in Patent Document 1 can be moved away from the boarding and alighting position while traveling, so it is thought that contact with the road surface is avoided and deformation or damage due to contact with the road surface does not occur. However, it requires equipment such as a motor and a controller, and its structure is not necessarily simple.

[0008] The present invention aims to solve the problems associated with the steps for climbing up and down in the cab of conventional heavy machinery such as carrier dumps, and has as its objective the realization of a step device for climbing up and down that allows the driver to climb up and down easily and safely, is able to suppress deformation or damage even when subjected to external forces due to interference from contact with the road surface, and has a relatively simple structure that can be easily attached to existing heavy machinery. [Means for solving the problem]

[0009] A step device for ascending and descending which is attached to a heavy machine and used for ascending and descending to a cab, the step device comprising a step portion, a mounting plate, and front and rear hanging lock portions respectively provided on the front and rear end sides of the mounting plate, the step portion comprising front and rear chains suspended at a distance from each other, and a footrest removably mounted between the front and rear chains, the front and rear hanging lock portions each comprising a locking bracket, a hanging bracket, a support shaft, and a compression coil spring, the locking bracket comprising a locking hole consisting of an upper circular hole portion and a lower elongated hole portion which communicates with the circular hole portion and extends downward, the hanging bracket is attached to and hangs the upper end of the chain of the step portion, and is disposed so as to surround the locking bracket from the outside. The support shaft has an oval cross-sectional shape consisting of upper and lower arc portions and two straight lines connecting the upper and lower arc portions, both ends of which are fixed to the hanging bracket and arranged horizontally, is rotatably inserted into the upper circular hole of the lock hole, is biased upward together with the hanging bracket by a compression coil spring attached to the lock bracket, and is rotatable around the upper circular hole of the lock hole, and when a downward external force is applied to the step portion, the hanging bracket moves downward and the support shaft descends against the compression coil spring and enters the long hole of the lock hole, the support shaft and the hanging bracket are locked so as not to rotate.

[0010] A step device for ascending and descending which is attached to heavy machinery and used for ascending and descending to a cab, the step device comprising a step portion, a mounting plate, and front and rear suspension lock portions provided on the front and rear end sides of the mounting plate, the step portion comprising front and rear chains suspended at a distance from each other, and a footrest removably mounted between the front and rear chains, the mounting plate being a member for fixing the step device for ascending and descending to the heavy machinery, the front and rear suspension lock portions each comprising a lock bracket, a suspension bracket, a support shaft, a support cylinder, and a compression coil spring, the lock bracket comprising front and rear side plates and a bottom plate, The front and rear side plates are provided with locking holes consisting of an upper circular hole and a lower elongated hole that communicates with the circular hole and extends downward, the hanging bracket comprises front and rear side plates and a bottom plate that suspends the step portion and is arranged to surround the locking bracket from the outside, one of the front and rear side plates of the hanging bracket has an oval mounting hole consisting of upper and lower arc portions and two straight lines connecting the upper and lower arcs, and the other side plate has a screw shaft insertion hole, the support cylinder is arranged inside the locking bracket and is urged upward by a compression coil spring provided on the bottom plate of the locking bracket, a support shaft having an oval cross-sectional shape similar to the mounting hole in one of the side plates of the hanging bracket, and rotatably inserted and positioned horizontally into the support cylinder and the upper circular hole of the lock hole, one end of the support shaft is fitted into the mounting hole in one of the side plates of the hanging bracket, and the other end of the support shaft is fixed with a nut by passing a screw shaft formed at the other end through a screw insertion hole in the other side plate of the hanging bracket, the support shaft is urged upward together with the hanging bracket by a compression coil spring via the support cylinder, the support shaft and the hanging bracket are rotatable around the upper circular hole of the lock hole, and when a downward external force is applied to the step portion, the hanging bracket moves downward, and the support shaft descends against the compression coil spring and enters the long hole at the bottom of the lock hole, the support shaft and the hanging bracket are locked so as not to rotate.

[0011] The front and rear ends of the footrest are formed with engaging protrusions that can be engaged with and disengaged from the front and rear chains, respectively. With the engaging protrusions engaged with the chains, mounting brackets that are concave-shaped in a plan view can be placed over the front and rear of the front and rear chains, respectively, to sandwich the front and rear chains and the footrest, and then screwed in place, thereby removably fixing the front and rear ends of the footrest to the front and rear chains, respectively.

[0012] The leg rest may also be mounted between the front and rear suspension brackets.

[0013] The compression coil spring is supported by a guide rod that is inserted therethrough, and it is preferable that the guide rod be configured to extend downward from the support cylinder and be slidably inserted into a hole formed in the bottom plate of the locking bracket. Effect of the Invention

[0014] The climbing step of the present invention is designed so that no external force is applied due to contact with the road surface, preventing deformation or damage, allowing the operator to climb up and down easily and safely, the footrest attachment height is adjustable, and the structure is simple, making it easy to attach to existing heavy machinery, thereby achieving the remarkable advantages.

[0015] In particular, the ascent and descent step device of the present invention is provided with a locking bracket that prevents the step portion from escaping deep into the bottom of the heavy machinery or from shaking when the operator ascends or descends, making it easier to ascend and descend and preventing the operator from falling when ascending or descending.

[0016] The ascent / descent step device of the present invention, during normal driving other than when the driver is ascending or descending, allows the step portion to rotate (swing) laterally relative to the direction of travel of the heavy equipment by releasing the lock provided by the locking bracket, thereby providing a degree of freedom so that the step portion can escape without resisting external forces from the lateral direction, such as those caused by the road surface, etc., thereby preventing deformation or damage.

[0017] The climbing step device of the present invention has a step portion configured with footrests attached to front and rear chains, which makes it possible to reduce impacts caused by interference with the road surface from the front-to-rear (traveling direction) of the heavy equipment and from below. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating an embodiment of a step device for ascent and descent according to the present invention, and is a diagram illustrating an overview of a carrier dump as an example of heavy machinery equipped with a step device for ascent and descent, where (a) is a front view seen from the side, and (b) is a front view seen from the front. [Diagram 2] FIG. 2 is a diagram for explaining the overall configuration of the ascending / descending step device of the embodiment. [Diagram 3] FIG. 2 is a perspective view illustrating components of the overall configuration of the ascending / descending step device of the embodiment. [Figure 4] This is a diagram for explaining the configuration for detachably attaching a footrest to a chain that is a part of the ascending / descending step device of the embodiment, and is a perspective view showing a state in which a part of the chain on the near side (left side) has been removed. The two-dot chain line indicates the near side (left part) of the mounting bracket. [Diagram 5] FIG. 1 is a diagram explaining the relative configuration of the support shaft, support cylinder, lock hole, compression coil spring, etc. of the hanging lock part, which is part of the ascent / descent step device of the above embodiment, and is an oblique view showing the state with the front side plate of the locking bracket and the front side plate of the hanging bracket removed. [Figure 6] 1A and 1B are diagrams for explaining the operation of the suspension lock part of the ascent / descent step device of the above embodiment, in which (a) shows the unlocked state with no feet placed on the footrest, (b) shows the state of the lock hole and support shaft in (a), (c) shows an enlarged view of the main parts of (b), (d) shows the locked state with a foot placed on the footrest, and (e) shows the state of the lock hole and support shaft in (d). [Figure 7] FIG. 1 shows a conventional ascending / descending step device, where (a) is a front view seen from the side, and (b) is a cross-sectional view taken along line AA of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a step device for ascending and descending according to the present invention will be described below with reference to the drawings. EXAMPLES

[0020] An embodiment of the ascent / descent step according to the present invention is shown in Fig. 1 to Fig. 6. In this embodiment, a carrier dump is taken as an example of heavy machinery to which the ascent / descent step is attached.

[0021] In this specification and claims, the forward and backward sides of a carrier dump (an example of heavy machinery) are referred to as the front and rear sides, and the left and right sides that are lateral to the forward direction are referred to as the left and right sides.

[0022] The carrier dump 1 shown in Figures 1(a) and (b) is of a conventional structure, with a base frame 3 mounted on crawlers 2, a loading platform 4 mounted at the rear of the frame 3, and a driver's cab 5, an engine 6, a hydraulic device 7, etc. mounted at the front.

[0023] The loading platform 4 is rotatably attached to the rear end of the frame 3, and is arranged so that the front end side rotates upward by hydraulic pressure from a hydraulic device 7, as shown in FIG. 1(a).

[0024] An ascending / descending step device 10 according to the present invention is mounted adjacent to a driver's cab 5 on a frame 3 or a member fixed to the frame 3, as shown in FIG. 1(a).

[0025] 2 and 3, the entire structure of the ascent / descent step device 10 is mainly comprised of a step portion 11, a mounting plate 12, and two suspension lock portions 13 provided on the front and rear end sides of the mounting plate 12. The structures of the step portion 11, the mounting plate 12, and the suspension lock portion 13 will be described below in order.

[0026] Step section: The step unit 11 is a step (ladder) for ascending and descending that is used when the driver ascends and descends to the driver's seat 5. As shown in Fig. 2, the step unit 11 is suspended from a suspension lock unit 13 and attached to the frame 3 of the carrier dump 1 or a member (not shown) fixed to the frame 3.

[0027] As a feature of the ascent / descent step device 10 according to the present invention, which will be described in detail later, when the operator ascends or descends, the step portion 11 is locked (restrained) from lateral swinging or movement by the suspension lock portion 13.

[0028] As shown in Figures 2 and 3, the step section 11 comprises a front chain 16 and a rear chain 16, one or more footrests 17 suspended in the front-to-rear direction between the two front and rear chains 16, and mounting brackets 18 for removably attaching the footrests 17 to the chains 16.

[0029] The front chain 16 and the rear chain 16 have the same configuration, so as shown in Figure 3, the rear chain 16 is made up of two rows of chains: a left chain 16a (the chain 16 on the front side shown in Figure 3) and a right chain 16b (the chain 16 on the back side shown in Figure 3).

[0030] The leg rests 17 are provided in two rows on the left and right sides, as shown in the rear portion in Fig. 3. The left and right leg rests 17 have the same configuration, and a plurality of projections 21 for preventing slipping and wiping off mud are formed on the upper surface, as shown in Figs. 2 and 3. The front and rear ends of the leg rests 17 are each formed with a wide portion 22, as shown in Figs. 2 and 3.

[0031] Since the front and rear ends of the legrest 17 have the same configuration, only the rear end of the legrest 17 will be described here. However, the wide portion 22 has holes 23 for screwing formed at the top and bottom, as shown in Figures 3 and 4.

[0032] For example, as shown in FIG. 3, the screw fastening hole 23a of the left footrest 17 is a screw insertion hole (an unthreaded through hole), and the screw fastening hole 23b of the right footrest 17 is a screw tap hole (a threaded hole).

[0033] An engagement protrusion 24 is formed at the end of the wide portion 22 of the legrest 17. Fig. 3 shows the rear end of the legrest 17, and the engagement protrusion 24 is formed so as to protrude rearward.

[0034] 3, the leg rest 17 shown on the left (nearest) side is not engaged with the chain 16, and the engagement protrusion 24 is clearly shown. Although not shown, the left and right leg rests 17 are also formed at their front ends with engagement protrusions 24 that protrude forward.

[0035] The mounting structure for detachably mounting the front and rear ends of the left and right footrests 17 to the left and right chains 16a, 16b, respectively, is the same. Here, with reference to Figures 3 and 4, the mounting structure for mounting the rear ends of the left and right footrests 17 to the left and right chains 16a, 16b, respectively, after selecting the mounting height, will be described.

[0036] When attaching the left and right footrests 17 to the left and right chains 16a, 16b, respectively, the engaging projections 24 of the left and right wide portions 22 are engaged with portions of the left and right chains 16a, 16b at selected heights, as shown in Figures 3 and 4.

[0037] The mounting bracket 18 is then positioned so as to surround the left and right chains 16a, 16b and the wide portions 22 of the left and right footrests 17 from behind, and the mounting screws 19 are inserted through the screw insertion holes 20 to secure them in place.

[0038] Mounting plate and lifting lock: The mounting plate 12 is a member for mounting the ascent / descent step device 10 including the mounting plate 12 itself to the underside of the frame 3 of the carrier dump 1 directly or via a mounting member (not shown) fixed to the frame 3. As shown in Fig. 3, the mounting plate 12 may be configured to have strength by providing reinforcing plates 30 on the left and right sides.

[0039] As shown in FIG. 2, the suspension lock portions 13 are provided respectively on the front and rear ends of the mounting plate 12, and each includes a locking bracket 31, a suspension bracket 32, a support shaft 33, a support cylinder 34, and a compression coil spring 35.

[0040] As shown in Figure 2, the hanging lock portion 13 is provided symmetrically on both the front and rear ends of the mounting plate 12. However, since the front and rear hanging lock portions 13 have the same configuration, the following description will focus on the configuration of the rear end hanging lock portion 13, with reference to Figures 2 to 6, etc.

[0041] In addition, in the claims, the side panels 50, 51 relating to the suspension bracket 32 ​​are described as one side and the other side in terms of the front and rear, respectively, but for the rear end suspension bracket 32, one side is the rear side and the other side is the front side, and also, for the front end suspension bracket 32, one side is the front side and the other side is the rear side.

[0042] Similarly, the claims describe the front and rear ends of the support shaft 33 as one end and the other end, but for the support shaft 33 of the rear end side suspension bracket 32, one end is the rear end and the other end is the front end, and for the support shaft 33 of the front end side suspension bracket 32, one end is the front side and the other end is the rear side.

[0043] There are two locking brackets 31, which are either integrally formed or separately fixed to the front and rear ends of the mounting plate 12, but in this embodiment, a configuration in which they are formed integrally is shown.

[0044] In addition, the locking brackets 31 provided on the front and rear ends of the mounting plate 12 are symmetrical and have the same configuration, so here we will explain the locking brackets 31 provided on the front and rear ends of the mounting plate 12.

[0045] As shown in Figures 3, 5, 6(a) and (d), the locking bracket 31 is integrally formed of front and rear side plates 40, 41 and a bottom plate 42, and when viewed from the side, it is formed overall in a concave shape (the vertical cross section along the front-to-rear direction is concave).

[0046] A keyhole-shaped lock hole 44 is formed in each of the front and rear side plates 40, 41 (see Figs. 3, 5, and 6(a) to (e)). The lock hole 44 is made up of an upper circular hole portion 45 and a lower elongated hole portion 46 that extends downward from the circular hole portion 45.

[0047] As shown in Figures 3, 5, 6(a) and (d), the suspension bracket 32 ​​is integrally formed from front and rear side plates 50, 51 and a bottom plate 52, and when viewed from the side, it is formed overall in a concave shape (the vertical cross section along the front-to-rear direction is concave).

[0048] An oval-shaped mounting hole 53 that is long in the vertical direction is formed in the upper part of the side plate 51 on the rear side (one side) of the hanging bracket 32. Note that a shape that has arc sections on the top and bottom and straight sections on the left and right is referred to as "oval-shaped" in this specification and claims.

[0049] In addition, a screw insertion hole 54 is formed in the upper part of the side plate 50 on the front side (the other side) of the suspension bracket 32, concentric with the vertical center of the mounting hole 53, as shown in Figures 3, 6(a) and (d).

[0050] The upper ends of the left and right chains 16a, 16b are fixed to the underside of the bottom plate 52 by screws and nuts via chain mounting blocks 58, as shown in Figures 2, 3, 6(a) and (d), so that the suspending bracket 32 ​​is configured to suspend the step portion 11.

[0051] In this embodiment, as shown in Fig. 2, the uppermost leg rest 17 is mounted between the front and rear hanging brackets 32. Such an uppermost leg rest 17 may be provided as needed, and may not be provided in some configurations.

[0052] When providing the topmost footrest 17, the rear end of the footrest 17 may be attached to the front side plate 50 of the rear suspension bracket 32 ​​as shown in FIG. 3, and the front end of the footrest 17 may be attached to the rear side plate of the front suspension bracket 32 ​​as shown in FIG. 2.

[0053] As shown in Figures 3, 5, and 6(c), the vertical cross section of the support shaft 33 perpendicular to its longitudinal direction is oval (having arc portions 61 on the top and bottom and vertical straight portions 62 on the left and right), which is similar in shape to the mounting hole 53 formed in the rear side plate 51 of the suspension bracket 32, and its cross-sectional dimensions are slightly smaller than those of the mounting hole 53 so that it can be fitted into and fixed in place.

[0054] The diameters of the upper and lower arcuate portions 61 in the vertical cross section of the support shaft 33 are slightly smaller than the diameter of the upper circular hole portion 45 of the locking hole 44 of the locking bracket 31, and are larger than the width of the lower elongated hole portion 46 of the locking hole 44. In addition, the widths of the left and right straight portions 62 in the vertical cross section of the support shaft 33 are smaller than the width of the lower elongated hole portion 46 of the locking hole 44 (see FIGS. 6(b), (c) and (e)).

[0055] With this configuration, the upper and lower arc portions 61 of the support shaft 33 can rotate within the circular hole portion 45 of the lock hole 44, but the support shaft 33 cannot rotate within the elongated hole portion 46 of the lock hole 44. When the arc portions 61 are facing up and down, the support shaft 33 can move down and enter the elongated hole portion 46.

[0056] 3, 6(a) and 6(d), the support shaft 33 has a threaded shaft 36 formed at its front end and a circular flange 63 formed at its rear end. The inside diameter of the support cylinder 34 is formed to be slightly larger than the diameters of the upper and lower arcuate portions 61 of the support shaft 33, and the support shaft 33 is inserted into the support cylinder 34 so as to be rotatable.

[0057] The upper end of the compression coil spring 35 is attached to the lower surface of the support cylinder 34 via a seat plate 66, and the lower end is attached to the bottom plate 42 of the locking bracket 31. As a result, an upward elastic force is constantly applied to the support shaft 33, which is rotatably inserted into the support cylinder 34, via the support cylinder 34.

[0058] In addition, a guide rod 67 that extends downward and is longer than the compression coil spring 35 is fixed to the underside of the seat plate 66. This guide rod 67 is inserted through the compression coil spring 35 and slidably inserted into a hole 47 formed in the bottom plate 42, thereby supporting the compression coil spring 35.

[0059] The significance of adopting such a configuration is as follows: In other words, in a configuration in which the support cylinder 34 is simply biased from below via the seat plate 66 by the compression coil spring 35 provided on the bottom plate 42 in order to bias the support cylinder 34 from below with an elastic force, when the support cylinder 34 rotates relative to the support shaft 33 and shifts in the circumferential direction, the compression coil spring 35 is subjected to movement in directions other than the axial direction, such as forward / backward / left / right, which may damage the compression coil spring 35 or cause problems in sufficiently biasing the support shaft 33 upward via the support cylinder 34.

[0060] Therefore, in order to prevent the support cylinder 34 from rotating relative to the support shaft 33, the support cylinder 34 is urged upward by a compression coil spring 35, which presses the support shaft 33 to prevent rotation by frictional resistance, and a guide rod 67 is inserted through the compression coil spring 35 to support it.

[0061] This limits movement of the compression coil spring 35 in any direction other than the axial direction, preventing damage to the compression coil spring 35 while enabling a sufficient upward elastic force to be applied to the support shaft 33 via the support cylinder 34.

[0062] The configuration of each member constituting the front and rear hanging lock parts 13 has been described above, and the configuration of the hanging lock part 13 assembled from such members will be further described below. Note that since the front and rear hanging lock parts 13 have the same configuration, the configuration of the rear hanging lock part 13 will be described here with reference to Figures 2, 3, 5, 6, etc.

[0063] As shown in FIGS. 2, 5, 6 and the like, the support cylinder 34 and the compression coil spring 35 are disposed within the locking bracket 31, and the locking bracket 31 is disposed inside the hanging bracket 32.

[0064] The rear end of the support shaft 33 is fitted and fixed into the mounting hole 53 of the rear side plate 51 of the hanging bracket 32, and the screw shaft 36 at its front end passes through the screw insertion hole 54 and is tightened with a nut 37 on the outside of the front side plate 50, so that it is fixed horizontally between the front and rear side plates 50, 52 of the hanging bracket 32.

[0065] The support shaft 33 is rotatably inserted into the circular hole portion 45 of the lock hole 44 of the rear side plate 41 of the locking bracket 31 between the front and rear side plates 50, 51 of the hanging bracket 32. This allows the locking bracket 31 to rotate together with the support shaft 33 around the circular hole portion 45.

[0066] Furthermore, since the support shaft 33 is rotatably inserted into the support cylinder 34 between the front and rear side plates 40, 41 of the locking bracket 31, as described above, the support shaft 33 is biased upward by an elastic force from the compression coil spring 35.

[0067] (action) The operation of the ascending / descending step device 10 configured as described above will be described below. The ascending / descending step device 10 is attached to the underside of the frame 3 of the carrier dump 1 by its mounting plate 12, either directly or via a member (not shown) provided for mounting the ascending / descending step device 10 fixed to the frame 3, near the driver's cab, as shown in FIG.

[0068] When the step device 10 is not in use, i.e., when the vehicle is not in operation and the driver is not using the step device 10 to get up or down from the driver's seat, or when the vehicle is traveling, as shown in Figures 2, 5, 6(a), (b), and (c), the support shaft 33 is biased upward via the support cylinder 34 by the elastic force of the compression coil spring 35, and is therefore located at the circular hole portion 45 of the lock hole 44 in the front and rear side panels of the lock bracket 31.

[0069] In this position, as described above, although the upward biasing force of the compression coil spring 35 prevents the support cylinder 34 and the support shaft 33 from rotating due to frictional resistance between them, if an external force of a certain magnitude is applied, the support shaft 33 can rotate (swing) within the circular hole portion 45 of the lock hole 44 and the support cylinder 34, and therefore the locking bracket 31, together with the support shaft 33, can rotate (swing) in the left-right direction (horizontal direction) relative to the direction of travel of the carrier dump 1.

[0070] Therefore, even if the step portion 11 receives external force from the left and right (lateral to the direction of travel) due to the road surface, stones, etc. while the carrier dump 1 is moving, the lifting bracket 32 ​​can rotate (swing) left and right to release the external force, thereby preventing the step portion 11 from being deformed or damaged.

[0071] Furthermore, for example, even if the step portion 11 comes into contact with the road surface and receives an external force from the front when the carrier dump 1 is climbing an uphill slope, the step portion 11 is configured with the footrest 17 attached to the chain 16, so that it is possible to release the external force without resisting it, and deformation or damage to the step portion 11 can be prevented.

[0072] By the way, when the step device 10 is in use, that is, when the driver uses the step device 10 to climb up and down to the driver's seat, when the driver places his / her foot on the footrest 17, the step portion 11, the hanging bracket 32, the support shaft 33 and the support cylinder 34 are caused to descend against the compression coil spring 35 by the driver's weight, as shown in Figures 6(d) and (e).

[0073] At this time, the support shaft 33 descends from the circular hole portion 45 of the lock hole 44 of the lock bracket 31 into the elongated hole portion 46 as shown in the transition from the state of FIG. 6(b) to the state of FIG. 6(e).

[0074] Then, the support shaft 33 is locked (restrained) so as not to rotate with respect to the locking bracket 31. Therefore, together with the support shaft 33, the lifting bracket 32 ​​and the step portion 11 are locked against left-right (lateral) movement with respect to the traveling direction of the carrier dump 1.

[0075] When the driver places his / her feet on the footrest 17 of the step portion 11, the step portion 11 is locked against movement in the lateral direction (front-to-back direction as seen from the driver when ascending or descending), so that the step portion 11 is prevented from moving forward or backward as seen from the driver's perspective, making it easier for the driver to ascend or descend.

[0076] As described above, with the ascent and descent step device 10 of the present invention, even if the driver places his / her foot on the step when ascending or descending, the step portion 11 equipped with the chain 16 is prevented from escaping or shaking in the lateral direction of the carrier dump 1 (to the rear or front side below the frame 3 of the carrier dump 1), making it easier for the driver to ascend and descend, and preventing falls, enabling the driver to ascend and descend safely.

[0077] The ascent / descent step device 10 of the present invention is configured with a step portion 11 and footrests 17 attached to front and rear chains 16, so that it is possible to mitigate impacts in the front-to-back directions (travel direction) and from below caused by interference between the step portion 11 and the road surface, and deformation and damage to the ascent / descent step device 10 can be suppressed.

[0078] Furthermore, during normal driving other than when the driver is ascending or descending, the ascent / descension step device 10 of the present invention allows the step portion 11 to rotate (swing) laterally relative to the direction of travel of the heavy equipment by releasing the lock provided by the locking bracket 31, thereby providing a degree of freedom and allowing the step portion 11 to escape without resisting external forces from the lateral direction such as the road surface, thereby preventing deformation or damage to the ascent / descension step device 10.

[0079] The above describes the form for implementing the step device for ascent and descent according to the present invention based on the examples. However, the present invention is not limited to such examples, and it goes without saying that there are various embodiments within the scope of the technical matters described in the claims. [Industrial Applicability]

[0080] The ascent / descent step device according to the present invention is applicable to various heavy machinery such as carrier dumps, forwarders, etc., used in the fields of construction, civil engineering, forestry, etc. [Explanation of symbols]

[0081] 1. Carrier Dump 2. Crawler 3 Frame 4 Cargo bed 5. Cab 6 Engine 7 Hydraulic system 10. Step device for ascending and descending 11 Step section 12 Mounting plate 13 Suspension lock section 16 Chain 17 Footrest 18 Mounting bracket 19 Mounting screws 20 Screw insertion hole 21 Unevenness of the footrest 22 Wide leg rest 23 Screw holes 24 Engagement protrusion 30 Reinforcement plate 31 Lock bracket 32 Lifting bracket 33 Support shaft 34 Support Cylinder 35 Compression coil spring 36 Screw shaft 37 Nut 40 Front side plate of locking bracket 41 Rear side plate of lock bracket 42 Locking bracket bottom plate 44 Lock hole 45 Circular hole of lock hole 46 Long hole of lock hole 47 Hole in bottom plate of locking bracket (hole for inserting guide rod) 50 Front side plate of lifting bracket 51 Rear side plate of the lifting bracket 52 Bottom plate of lifting bracket 53 Mounting hole on rear side plate of lifting bracket 54 Screw insertion hole in front side plate of lifting bracket 58 Chain mounting block 61 Upper and lower arcs of cross section of support shaft 62 Vertical straight section of cross section of support shaft 63 Support shaft flange 66 Seat board 67 Guide rod extending downward from the seat plate 71 Conventional step device 72 Mounting material 73 Steps 74 Rod material 75 Footrest

Claims

1. A step device for ascending and descending, which is equipped with a step portion, a mounting plate, and front and rear suspension lock portions provided on the front and rear end sides of the mounting plate, and is attached to a heavy machine to be used for ascending and descending to a cab, The step section includes front and rear chains suspended at intervals from each other, and a footrest removably mounted between the front and rear chains. The front and rear suspension lock parts each include a lock bracket, a suspension bracket, a support shaft, and a compression coil spring. The lock bracket has a lock hole consisting of an upper circular hole portion and a lower elongated hole portion that communicates with the circular hole portion and extends downward, The hanging bracket is attached to the upper end of the chain of the step section and is arranged to surround the locking bracket from the outside. a lifting step device characterized in that the support shaft has an oval cross-sectional shape consisting of upper and lower arc portions and two straight lines connecting the upper and lower arc portions, is fixed at both ends to the hanging bracket and arranged horizontally, is rotatably inserted into the upper circular hole portion of the locking hole, is biased upward together with the hanging bracket by a compression coil spring attached to the locking bracket, and is rotatable around the upper circular hole portion of the locking hole, and when a downward external force is applied to the step portion, the hanging bracket moves downward and the support shaft descends against the compression coil spring and enters the long hole portion of the locking hole, the support shaft and the hanging bracket are locked so that they cannot rotate.

2. A step device for ascending and descending, which is equipped with a step portion, a mounting plate, and front and rear suspension lock portions provided on the front and rear end sides of the mounting plate, and is attached to a heavy machine to be used for ascending and descending to a cab, The step section includes front and rear chains suspended at intervals from each other, and a footrest removably mounted between the front and rear chains. The mounting plate is a member for fixing the step device to the heavy equipment. The front and rear suspension lock parts each include a lock bracket, a suspension bracket, a support shaft, a support cylinder, and a compression coil spring. The locking bracket has front and rear side plates and a bottom plate, and the front and rear side plates have locking holes each having an upper circular hole portion and a lower long hole portion that communicates with the circular hole portion and extends downward, The suspension bracket has front and rear side plates and a bottom plate for suspending the step portion, and is arranged to surround the locking bracket from the outside. One of the front and rear side plates of the suspension bracket has an oval mounting hole formed therein, the mounting hole being composed of upper and lower arc portions and two straight lines connecting the upper and lower arcs, and the other side plate has a screw shaft insertion hole formed therein. The support cylinder is disposed inside the locking bracket and is biased upward by a compression coil spring provided on the bottom plate of the locking bracket. The support shaft has an oval cross-sectional shape similar to the mounting hole in one side plate of the hanging bracket, and is rotatably inserted into the support cylinder and the circular hole at the top of the lock hole and arranged horizontally. One end of the support shaft is fitted into the mounting hole in one side plate of the hanging bracket, and the other end of the support shaft is fixed with a nut by passing a screw shaft formed at the other end through a screw insertion hole in the other side plate of the hanging bracket. The support shaft is biased upward together with the hanging bracket by a compression coil spring via a support cylinder. This ascent and descent step device is characterized in that the support shaft and the hanging bracket are rotatable around the circular hole at the top of the lock hole, and when a downward external force is applied to the step portion, the hanging bracket moves downward and the support shaft descends against the compression coil spring and enters the long hole at the bottom of the lock hole, the support shaft and the hanging bracket are locked so that they cannot rotate.

3. The step device for ascent and descent as described in claim 1 or 2, characterized in that the front and rear ends of the footrest are formed with engaging protrusions that can be engaged and detached with the front and rear chains, respectively, and with the engaging protrusions engaged with the chains, mounting brackets that are concave-shaped in a plan view are placed over the front and rear of the front and rear chains, respectively, so as to sandwich the front and rear chains and the footrest, and then screwed in place, thereby removably fixing the front and rear ends of the footrest to the front and rear chains, respectively.

4. 4. The step device for ascending and descending according to claim 3, wherein the footrest is also mounted between the front and rear suspension brackets.

5. 3. A step device for ascent and descent as described in claim 1 or 2, characterized in that the compression coil spring is supported by a guide rod inserted therethrough, the guide rod being arranged facing downward from the support cylinder and slidably inserted into a hole formed in the bottom plate of the locking bracket.

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