Crawler apparatus and transportation cart

Abstract

To provide a crawler apparatus making it possible to upgrade a load-bearing capacity per an apparatus weight and upgrade a travel capability on an uneven ground, and a transportation cart including the crawler apparatus.SOLUTION: A track belt 30 includes a fabric core belt 31 that is deformable but unshrinkable, and plural roller elements 40 and non roller elements 50 which are alternately attached to the whole of the core belt 31 with a predetermined space between adjoining ones. A covering plate 70 is fixed to each of the underparts of the roller elements 40 and non roller elements 50. Through holes for use in fixing the roller elements 40 and non roller elements 50 are formed at regular intervals in the core belt 31, thought they are not shown. The roller elements 40 and non roller elements 50 are attached in line with the through holes, whereby a gap whose width is about 15% of the thickness of the covering plate 70 is formed between the adjacent covering plates 70.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an endless track device and a transport vehicle equipped with the endless track device. [Background technology]

[0002] Conventionally, wheels such as casters have been used for running mechanisms without a prime mover that are attached to hand-pushed transport carts and the like. However, on unpaved ground or in places with many steps, the wheels tend to sink, making it impossible for the cart to run or to overcome the steps, limiting the places where the cart can run.

[0003] As a traveling mechanism capable of traveling on such terrain, Patent Document 1 discloses a transport vehicle equipped with a caterpillar track device in which large pulleys are arranged at the front and rear in the direction of travel, a number of small pulleys are arranged on the ground side, and a track belt is wound around the large and small pulleys.

[0004] Patent Document 2 also discloses a transport vehicle equipped with a running device that utilizes the caterpillar track device of grass skiing equipment. In this endless track device, a track roll covers an elongated rail, and a number of elements with rollers are attached to the inner circumference of the track roll at positions where they come into contact with the rail. The elements further have plates on the outer circumference of the track roll. Each element is fixed to a belt that maintains a constant interval on the rail. Therefore, when the cart is pushed, the plates stop due to friction with the ground, but the rollers rotate, allowing the rails to move in the direction the cart is pushed. And because the belts maintain the distance between the front and rear plates, as the rails move, the plates also circulate along the rails.

[0005] These track devices have a wide contact area and can provide lower ground pressure than wheels, making them less likely to get stuck in grooves in the ground. Also, when going over a step, the step can be overcome using only forward force after the front of the track roll touches the step, making them more advantageous than wheels, especially when used outdoors. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7007694 [Patent Document 2] Patent No. 6243224 Summary of the Invention [Problem to be solved by the invention]

[0007] The track device described in Patent Document 1 has a complex structure, which tends to increase the weight of the device and the running resistance. Furthermore, in order to improve the load-bearing capacity, it is necessary to adopt a method of increasing the strength of the device by enlarging the shafts and bearings that support the load, or a method of distributing the load by increasing the length and width of the device, which tends to increase the size of the entire device and the weight of the device.

[0008] In contrast, the structure disclosed in Patent Document 2, which holds elements at regular intervals, reduces the number of elements, thereby reducing the weight of the device and reducing the running resistance. Reducing the weight of the device leads to an improvement in the load capacity per unit weight of the device, making it easier to move the cart by hand. Therefore, the caterpillar track device described in Patent Document 2 is more advantageous for a running device that does not have a prime mover than the crawler described in Patent Document 1.

[0009] However, in such an endless track device, when the core belt portion runs over a step, the run-over portion deforms and becomes concave, increasing the tension in the core belt. The higher the tension in the core belt, the more strongly the elements are pressed against the rail, increasing the rotational resistance of the rollers and, as a result, increasing the running resistance. Furthermore, if the tension in the core belt becomes particularly high, the rollers will be unable to rotate, causing the circulation of the track belt to stop and making it impossible for the bogie to move. This is particularly problematic when entering places where the area where the track shoes can make contact with the ground is limited. For example, at construction sites for building foundations, transport vehicles must run on rebar before concrete is poured, but because the core belt is exposed, the load may be placed only on the core belt. In addition, heavy loads such as building materials and tools are likely to be applied to the transport vehicles.

[0010] In this regard, the crawler device described in Patent Document 1 does not have an exposed core belt, and even if a part of the track plate where there is no roller directly above is pressed, the regulating convex portion on the track plate fits into the regulating concave portion of the adjacent track plate, thereby regulating deformation toward the inner circumference of the track, and part of the track does not sink toward the inner circumference and the tension in the core belt does not increase, so that the crawler device described in Patent Document 2 has a higher rough terrain driving capability. For these reasons, it has been difficult to simultaneously improve the load-bearing capacity per unit weight of a tracked device that does not have a prime mover and improve its off-road travel capability.

[0011] Therefore, an object of the present invention is to provide an endless track device that can improve the load-bearing capacity per device weight and also improve the traveling ability on rough ground, and a transport vehicle equipped with such an endless track device. [Means for solving the problem]

[0012] A first invention is an endless track device comprising: an annular rail having a bottom portion long in the horizontal direction, a first bent portion having one end connected to one end of the bottom portion and extending upward while curving, a second bent portion having one end connected to the other end of the bottom portion and extending upward while curving, and a circulating portion connecting the other end of the first bent portion and the other end of the second bent portion; and an annular track belt covering the entire rail from the outer periphery along its shape, wherein the track belt is an endless track device that circulates along the rail, the track belt comprising an annular core belt having longitudinal ends connected to each other, and a plurality of elements to which track shoes are fixed, the elements being attached around the entire circumference of the core belt at intervals such that a predetermined gap is formed between adjacent track shoes, The predetermined gap has a width narrower than a thickness of the track plate.

[0013] A second invention is an endless track device characterized in that the track belt described in the first invention has as its elements a first element having a main roller that contacts the outer periphery of the rail on the inner periphery of the core belt and a second element that does not have the main roller attached alternately.

[0014] A third invention is an endless track device, characterized in that a reinforcing member having a length equal to or shorter than the length of the bottom portion is fixed to the inner periphery of the rail on the bottom portion.

[0015] A fourth invention is an endless track device according to the first invention, characterized in that the bottom portion has a flat shape.

[0016] The fifth invention relates to the track shoe according to the second invention, and further relates to a track shoe having ... This is an endless track device characterized in that a chamfer is provided between the other end surface and the ground contact surface.

[0017] A sixth invention is an endless track device characterized in that the first element described in the second invention is provided with a guide roller that is located on the inner side of the rail when the main roller is located at the bottom and that forms a gap of up to 0.5 mm between itself and the inner surface of the rail.

[0018] The seventh invention is the first element according to the second invention, wherein the first element has at least one main roller shaft that is horizontal and oriented perpendicular to the circulating direction of the track belt, on each side of the center of the circulating direction, The endless track device is characterized in that the main rollers are provided on both sides of the axial center of the main roller shaft.

[0019] An eighth aspect of the present invention is a transport vehicle comprising the caterpillar track device according to any one of the first to seventh aspects of the present invention. Effect of the Invention

[0020] According to the present invention, it is possible to provide an endless track device that can improve the load-bearing capacity per device weight and also improve the traveling ability on rough ground, and a transport vehicle equipped with the endless track device. [Brief description of the drawings]

[0021] [Figure 1] 1 is a perspective view showing an endless track device according to one embodiment of the present invention; [Diagram 2] 2 is a side view showing the structure of a frame and a rail of the endless track device shown in FIG. 1. [Diagram 3] 2 is a side view showing the structure of a track belt provided in the endless track device shown in FIG. 1. [Figure 4] FIG. 4 is an enlarged view of part I in FIG. [Diagram 5] 4A and 4B are a front view and a bottom view showing the structure of a roller upper element constituting the track belt shown in FIG. [Figure 6] FIG. 4 is a perspective view showing a structure of a lower element constituting the track belt shown in FIG. [Figure 7] 4A and 4B are a perspective view and a side view showing a structure of a track shoe that constitutes the track belt shown in FIG. [Figure 8] FIG. 2 is a perspective view showing a transporting platform vehicle to which the caterpillar track device shown in FIG. 1 is attached. [Figure 9] 9 is a side view showing a state of a track belt when the caterpillar track device shown in FIG. 8 runs over a protrusion on the ground. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or similar parts are denoted by the same or similar reference numerals, and duplicate explanations are omitted. In addition, the embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, markings, etc. of the components.

[0023] In the following explanations and drawings relating to the configuration or structure of the track device, unless otherwise specified, the lower left side in the perspective view and the left side in the side view are the "front side" of the track device, the upper right side in the perspective view and the right side in the side view are the "rear side" of the track device. The upper side in each view is the "upper side" and the lower side is the "lower side". Note that the "right side" and "left side" are determined based on the definitions of front, back, and top and bottom, so detailed definitions will be omitted. According to this definition, the direction along an imaginary straight line that connects the front and back sides horizontally is the "front-back direction", the direction along an imaginary straight line that connects the left and right sides horizontally is the "left-right direction", and the direction along the top is the "right-left direction". The direction along an imaginary straight line vertically connecting the top side and the bottom side is defined as the "up-down direction." In addition, the endless track device 1 according to this embodiment is configured so that the entire device is symmetrical in the front-rear and left-right directions, so the distinction between front-rear and left-right is for convenience's sake. Also, the circulating direction of the track belt is the front-rear direction.

[0024] <Structure of the track device> First, the overall structure of the caterpillar track device will be described with reference to FIG. The endless track device according to the present invention is usually used in combination with two or more units, but since devices of the same structure can be arranged side by side, only one unit will be described.

[0025] The endless track device 1 comprises a frame 10 which serves as a fixed part when attached to a platform for a trolley or the like, a rail 20 held by the frame 10, and a track belt 30 which covers the rail 20 from the outside. Next, the structure of each component will be explained. <Frame structure>

[0026] First, the structure of the frame 10 will be described with reference to FIGS. The frame 10 is composed of an upper frame 11 having an inverted U-shaped cross section, a lower frame 12 having a V-shaped vertical cross section, and a reinforcing member 13 in the shape of a square bar.

[0027] The upper frame 11 has an opening 11a formed in the center in the left-right direction, covering approximately 70% of the area, with the top surface and the upper parts of the left and right surfaces removed, and the lower frame 12 has an inverted V-shaped opening 12a formed in the center in the left-right direction. The openings 11a and 12a are formed so that foreign matter such as soil picked up by the track belt 30 can be easily discharged from inside the frame 10.

[0028] Three lower frames 12 are fixed to the lower part of the frame 10 at equally spaced positions in the front-rear direction, and reinforcing members 13 are fixed to the undersides of the lower frames 12 in a direction along the front-rear direction. The bottoms 21 of the rails 20, which will be described next, are fixed to the reinforcing members 13. The length of the reinforcing member 13 is equal to the length from the front end of the lower frame 12 located on the front side to the rear end of the lower frame 12 located on the rear side, and this length is shorter than the bottom 21.

[0029] <Rail structure> The structure of the rail 20 will now be described with reference to FIGS. The rail 20 is formed in a ring shape that is long in the front-rear direction by connecting the ends of plate-like members, and about 75% of the lower side is a bottom portion 21 that has a flat shape. A first bent portion 22A and a second bent portion 22B are formed at the front and rear of the bottom portion 21, which extend upward while curving, and in particular, the lower side is formed as a large angle of attack portion 23A, 23B, which is an arc shape with a larger radius than the upper side. The upper portions of the first bent portion 22A and the second bent portion 22B are connected by a circulating portion 24 that is parallel to the bottom portion 21.

[0030] The above-mentioned reinforcing member 13 is a member for maintaining the shape of the bottom portion 21, and as described above, has a length equal to or shorter than the bottom portion 21. Therefore, when the rail 20 is fixed to the reinforcing member 13, the reinforcing member 13 does not protrude into the range of the large attack angle portions 23A and 23B when viewed from the up-down direction.

[0031] <Track belt structure> Next, the structure of the track belt 30 will be described with reference to Figs. The detailed structure of each element will be described later. Hereinafter, the element in which the roller upper element 41 and the lower element 60 are fixed will be referred to as the roller element 40, and the element in which the non-roller upper element 51 and the lower element 60 are fixed will be referred to as the non-roller element 50.

[0032] The track belt 30 is composed of a cloth core belt 31 that is deformable but non-stretchable, a roller element 40 that has main rollers 43a-43d and guide rollers 45a, 45b at its upper part that contact the rail 20 and has a track shoe 70 fixed to its lower part, and a non-roller element 50 that does not have the main rollers 43a-43d and guide rollers 45a, 45b and has a track shoe 70 fixed to its lower part.

[0033] The core belt 31 has pin holes 32 at predetermined intervals in the center of the width direction throughout the entire area for passing pins 62a and 62b described later, and bolt holes 33 for passing bolts B are opened at equal intervals in positions shifted to the right of the center in the width direction and in positions shifted to the left of the center. By alternately attaching the roller elements 40 and the rollerless elements 50 in accordance with the positions of the pin holes 32 and the bolt holes 33, each element is positioned so that a gap G1 having a width of approximately 15% of the thickness of the track plate 70 is formed between adjacent track plates 70.

[0034] <Element structure> 3 and 5(a) and (b), the structures of the roller element 40 and the rollerless element 50 will be described. Note that the rollerless upper element 51 is a plate-like member having substantially the same shape as the bottom 46 of the roller upper element 41, and therefore a detailed description thereof will be omitted. The first element, roller element 40, is configured from a roller upper element 41 which has a square U-shape when viewed from the front-to-rear direction and has a triangular portion convex upward when viewed from the left-right direction and a rectangular portion below the triangular portion of approximately the same height as the triangular portion, and a lower element 60 to which the track shoe 70 is fixed. The second element, or rollerless element 50, is made up of a rollerless upper element 51 which is a flat plate-shaped member, and a lower element 60 to which the track shoe is fixed.

[0035] The roller upper element 41 is provided with main roller shafts 42a, 42b and guide roller shafts 44a, 44b whose axial directions run along the left-right direction in a triangular portion when viewed from the left-right direction. The main roller shafts 42a, 42b are located on the base side of the triangle, and the guide roller shafts 44a, 44b are located on the upper side. Main rollers 43a to 43d are supported on the front right, front left, rear right and rear left sides of the main roller shafts 42a and 42b, and guide rollers 45a and 45b having a smaller diameter than the main rollers 43a to 43d are supported on the guide roller shafts 44a and 44b.

[0036] Specifically, the guide rollers 45a, 45b are disposed at positions such that the distance between their lower portions and the upper portions of the main rollers 43a to 43d is at most 0.5 mm wider than the thickness of the rail 20. Therefore, when the rail 20 is sandwiched between the main rollers 43a to 43d and the guide rollers 45a, 45b, a gap G2 of at most 0.5 mm wide is formed between the inner peripheral surface of the rail 20 and the guide rollers 45a, 45b.

[0037] The bottom 46 of the roller upper element 41 and the wide surface of the non-roller upper element 51 are provided with bolt holes 47a, 47b located at the center right and left in the front-to-rear direction, penetrating in the up-down direction and with female threads. Also, fitting holes 48a, 48b for fitting pins 62a, 62b of the lower element 60 (described later) are formed at the center front and rear sides in the left-to-right direction. Furthermore, in two central areas obtained by dividing the surface into four in the front-to-rear direction, there are two belt fixing holes in the shape of a rectangle that is long in the left-to-right direction in each area. 49a to 49d are formed.

[0038] In the present embodiment, the roller upper element 41 has a shape in which the front, rear and top surfaces are open, and the main roller shafts 42a, 42b, the main rollers 43a to 43d, the guide roller shafts 44a, 44b and the guide rollers 45a, 45b are arranged in an open space, so that foreign matter such as soil picked up by the track belt 30 is less likely to accumulate. Therefore, the accumulation of foreign matter inside the roller upper element 41 is prevented from impeding the rotation of the main rollers 43a to 43d and the guide rollers 45a, 45b.

[0039] Next, the structure of the lower element 60 will be described with reference to FIG. Through holes 61a, 61b penetrating in the up-down direction are formed on the left and right central sides in the front-to-rear direction on the upper surface of the lower element 60, and pins 62a, 62b which are protrusions extending upward are formed on the front and rear central sides in the left-to-right direction. Furthermore, in two central areas obtained by dividing the surface into four in the front-to-rear direction, two belt fixing protrusions 63a to 63d each having a substantially rectangular shape are formed, each extending long in the left-to-right direction and upward. Further, element side mounting portions 64a to 64d are formed on the front and rear sides of the left and right side surfaces, respectively, which extend downward and have claws at their lower ends that protrude toward the center in the left-right direction.

[0040] <Structure of the track shoe> Next, the structure of the track shoe 70 will be described with reference to FIG. The track shoe 70 has a concave cross-sectional shape when viewed from the front-to-rear and left-to-right directions, and is a rectangular member with rounded corners when viewed from the top-to-bottom direction. A rectangular plane that is long in the front-to-back direction is formed at the bottom of the outer surface 71 as a ground contact surface 76.

[0041] A T-shaped beam 73 is formed on the inner surface 72 to a height that does not protrude upward from the inner surface 72 in order to reinforce the track shoe 70. Since the beam 73 is formed to improve the strength of the track shoe 70, any shape can be selected. Additionally, on the front left, front right, rear left and rear right sides of the inner surface 72, there are formed rectangular receiving holes 74a-74d that are elongated in the front-rear direction and penetrate in the up-down direction. Additionally, from the left-right center sides of the receiving holes 74a-74d, there are formed track shoe side attachment portions 75a-75d each having a claw extending upward and outward in the left-right direction.

[0042] The operation will be described later, but in particular, chamfers 77 consisting of curved surfaces with arc-shaped longitudinal sections are formed on the outer surface 71 between the front surface and the ground contact surface 76 and between the rear surface and the ground contact surface 76, with a width that is approximately two-thirds of the thickness of the track shoe 70. Note that the chamfers 77 are not limited to R-chamfers as shown in this embodiment, but may be C-chamfers or chamfers with an angle with the ground contact surface 76 other than 45 degrees.

[0043] <How to assemble the track device> 3 to 7, a method for assembling the endless track device 1 will be described. Note that, with regard to the method for fixing the roller upper element 41, the rollerless upper element 51, the lower element 60, and the track shoe 70 to the core belt 31, the method for fixing the rollerless upper element 51 to the core belt 31 is similar to that for the roller upper element 41, so the description will be omitted.

[0044] First, the roller upper element 41 is attached to the rail 20. At this time, the guide roller shafts 44a, 44b are removed from the roller upper element 41, and the main rollers 43a to 43d are brought into contact with the outer periphery of the rail 20, and then the guide roller shafts 44a, 44b and the guide rollers 45a, 45b are attached.

[0045] Next, the wide surface of the core belt 31 is aligned with the bottom 46 of the roller upper element 41. At this time, the bolt holes 47a, 47b are aligned with the bolt holes 33 of the core belt 31, and the fitting holes 48a, 48b are aligned with the pin holes 32 of the core belt 31. Then, the lower element 60 is attached from the outer periphery so as to sandwich the core belt 31. At this time, although the illustration of the roller upper element 41 side is omitted, the pins 62a, 62b are fitted into the fitting holes 48a, 48b, and the bolt B is screwed into the bolt holes 47a, 47b via the through holes 61a, 61b, thereby fixing the roller upper element 41 and the lower element 60, and the roller element 40 is attached to the core belt 31. Thereafter, the same procedure is repeated to alternately attach the roller elements 40 and the rollerless elements 50 around the entire circumference of the core belt 31 .

[0046] After the roller elements 40 and the rollerless elements 50 are attached to the entire circumference of the core belt 31, the track shoes 70 are fixed to the respective lower elements 60. To achieve this, the element side mounting portions 64a-64d and the track shoe side mounting portions 75a-75d are aligned, and the track shoe 70 is pressed against the lower element 60. This causes the element side mounting portions 64a-64d and the track shoe side mounting portions 75a-75d to deform relative to each other due to their elasticity, the element side mounting portions 64a-64d are received in the receiving holes 74a-74d, and the claws at the tips engage with each other, thereby fixing the track shoe 70 in place.

[0047] In addition to the pins 62a, 62b and the bolt B, the roller elements 40 and the rollerless elements 50 are also fixed to the core belt 31 by the belt fixing protrusions 63a to 63d attempting to fit into the belt fixing holes 49a to 49d, thereby deforming and pinching the core belt 31.

[0048] When removing the track shoe 70 from the lower element 60, a tool such as a flat-head screwdriver is inserted into the accommodation holes 74a-74d of the track shoe 70 to deform the element side mounting portions 64a-64d, thereby releasing the hook portions of the track shoe 70. Therefore, the track shoes 70 can be attached and detached to the track belt 30 without removing the roller elements 40 and the rollerless elements 50 from the core belt 31.

[0049] After the track shoes 70 are attached, the reinforcing members 13 are fixed to the bottoms 21 of the rails 20, and the lower frame 12 is then fixed to the top of the reinforcing members 13. Finally, the upper frame 11 is fixed to the top of the lower frame 12, thereby completing the assembly of the endless track device 1. <Operation / effect>

[0050] Next, the operation and function of the track device 1 will be described with reference to Figures 8 and 9, taking as an example a hand-pushed transport vehicle 2 equipped with the track device 1. In the following description, the side of the transport vehicle 2 on which the handle 3 is provided is defined as the rear side, and front, back, left, right, and up and down are defined based on an operator standing at the rear of the transport vehicle 2 and holding the handle 3. The transport vehicle 2 is provided with one endless track device 1 on each of the right and left sides of the bottom of the top plate, with the track belts 30 oriented in such a way that they move along the front-rear direction.

[0051] When the transport vehicle 2 travels over a protrusion OB on the ground, the track shoe 70 located at the front high angle of attack portion 23A or the rear high angle of attack portion 23B first comes into contact with the protrusion OB. Here, since only the bottom portion 21 of the rail 20 is fixed to the reinforcing member 13, the entire rail 20 elastically deforms when an impact is applied to a portion other than the bottom portion 21. In this manner, the elastic deformation of the rail 20 reduces the impact during travel. Also, since the rail 20 is provided with the high angle of attack portions 23A and 23B, the rail 20 has improved lifting ability compared to rails with semicircular front and rear ends.

[0052] As shown in FIG. 9, when the track shoe 70 riding on a protrusion OB on the ground is fixed to the rollerless element 50, the load cannot be transmitted directly from the track shoe 70 to the rail 20. In such a case, the rollerless element 50 is pushed toward the rail 20, and the core belt 31 is deformed to approach the rail 20. At this time, the other elements move toward the pressed rollerless element 50, and the core belt 31 is deformed to be recessed toward the inner periphery, so that the tension of the core belt 31 increases. As a result, the load applied to the main rollers 43a to 43d increases. If the load applied to the main rollers 43a to 43d continues to increase, the main rollers 43a to 43d will become unable to rotate, causing the track belt 30 to stop, and the transport vehicle 2 will also stop.

[0053] In this embodiment, when the rollerless element 50 is pressed and the core belt 31 is deformed as described above, the roller elements 40 arranged in front of and behind the pressed rollerless element 50 are pulled by the core belt 31 and tilt slightly. This is because the gap G2 is provided between the rail 20 and the guide rollers 45a, 45b, so that the roller element 40 can rotate around the main roller shaft 42a or 42b on the rollerless element 50 side.

[0054] When the roller element 40 tilts to a predetermined angle, the chamfer 77 of the track shoe 70 fixed to the non-roller element 50 comes into contact with the front or rear surface of the track shoe 70 fixed to the roller element 40. The core belt 31 is made of cloth and is therefore freely deformable, but does not stretch. Therefore, the load pressing against the non-roller element 50 is converted into a force that causes the track shoe 70 fixed to the roller element 40 to pinch the track shoe fixed to the non-roller element 50 and compress it from the front and rear. This compressive force also includes a component that presses the track shoe fixed to the non-roller element 50 against the rail, but because the core belt 31 does not stretch, it acts as a force that fixes the track shoe 70 in a pinched state.

[0055] At this time, the force pressing the track plate fixed to the rollerless element 50 is transmitted to the front and rear roller elements 40 via the core belt 31. In addition, since this pressing force is changed to a force compressing the track plate 70 of the rollerless element 50 from the front and rear, it is also transmitted to the roller element 40 by the reaction force of this compressive force.

[0056] In this embodiment, the gap between the track plates 70 is set to approximately 15% of the thickness of the track plate. This is to maintain a clearance for the smooth circulation of the track belt 30 between the roller element 40 and the rollerless element 50, while positioning the track plate 70 fixed to the rollerless element 50 so that it is sandwiched between the front and rear track plates 70 and can transmit ground contact load. Therefore, the distance between adjacent track shoes 70 can be set to a maximum of the thickness of the track shoes 70. This is because if the exposed amount of the core belt 31 is greater than the thickness of the track shoes 70, when the rollerless element 50 deforms toward the inner circumference of the rail 20, it will move to a position where it does not come into contact with the front and rear track shoes 70.

[0057] <Effects> The endless track device 1 of the present invention is provided with track shoes 70 around the entire circumference of the core belt 31, and therefore provides greater protection for the core belt 31 than conventional endless track devices in which the core belt 31 is exposed. Furthermore, because the track shoes are in contact with the ground over the entire lower area of ​​the endless track device 1, ground pressure is easier to reduce than with conventional endless track devices, and running performance on rough ground is superior. Furthermore, by providing track shoes 70 around the entire circumference, the track shoes 70 can make contact with the ground even in places where contact points are limited. This makes it possible to prevent the core belt 31 from directly contacting the ground, thereby making it possible to protect the core belt 31.

[0058] In the track belt 30 of the endless track device 1 according to the present invention, the roller elements 40 and the rollerless elements 50 are arranged alternately, and as described above, even if a load is applied so that the rollerless elements 50 are pressed, the load can be transmitted to the front and rear roller elements 40. This prevents the tension of the core belt 31 from increasing to the extent that the circulation of the track belt 30 stops, making it possible to prevent unintended stops during travel.

[0059] Furthermore, because the roller elements 40 and the rollerless elements 50 are arranged alternately, even if the roller elements 40 are enlarged, the roller elements 40 are less likely to interfere with each other, and it is easy to enlarge the main rollers 43a to 43d, so that the load capacity can be easily improved.

[0060] When the rail 20 is deformed by an impact during travel, the parts other than the bottom 21 reinforced by the reinforcing member 13 are deformed. Therefore, if the reinforcing member 13 is hanging on the high angle of attack parts 23A, 23B, slippage occurs between the rail 20 and the reinforcing member 13 when the rail 20 is deformed. This slippage becomes larger as the reinforcing member 13 approaches the high angle of attack parts 23A, 23B. Since the rail 20 repeatedly undergoes minute deformations during travel, fretting occurs in which minute slippage is repeated at the contact parts between the inner circumferential surface of the rail 20 and the reinforcing member 13. In the endless track device of the present invention, the reinforcing member 13 is sized so as not to overlap the high angle of attack portions 23A, 23B, and is positioned so as not to deviate from the bottom 21, thereby preventing the occurrence of such fretting, and thereby improving the durability of the rail 20 and the reinforcing member 13.

[0061] In the endless track device 1 according to the present invention, the roller elements 40 and the non-roller elements 50 are arranged alternately, so it is easy to reduce the weight of the device compared to when the roller elements 40 are arranged all around. In addition, the weight of the circulating track belt 30 is also lighter, so it is easy to reduce the running resistance, and by arranging the non-roller elements 50, which have a simpler structure, instead of the roller elements 40, it is also possible to reduce costs.

[0062] Unlike conventional crawler belt devices that have rollers and guide wheels, the endless track device of the present invention does not require an axle for connecting the crawler belt or an axle for supporting the rollers, so friction at the axle can be reduced. In addition, since the structure is simpler than that of conventional crawler belt devices, the weight of the device can be reduced. Therefore, it is easier to reduce the running resistance than conventional crawler belt devices.

[0063] Because the track plate 70 of the endless track device according to the present invention is formed with chamfers 77, there are no corners at positions where compressive force acts, and the track plate 70 fixed to the rollerless element 50 is pressed against the inner circumference of the rail 20, preventing stress concentration when adjacent track plates 70 interfere with each other. This makes it possible to improve track plate strength, which is one of the challenges in improving load resistance. Furthermore, since there is no need to form restricting protrusions and restricting recesses on the track shoes as in the crawler device disclosed in Patent Document 1, it is also possible to reduce manufacturing costs.

[0064] In addition, since the guide rollers 45a, 45b are disposed on the inner periphery side of the rail 20, the clearance between the rail 20 and the guide rollers 45a, 45b can be narrower than that of an endless track device in which a sliding member is disposed on the inner periphery side of the rail 20. Therefore, it is easy to suppress pitch rotation and roll rotation of the elements, and the main rollers 43a to 43b on the ground side In this way, the load is distributed to the main rollers 43a to 43d on the ground side, and thus the durability of the main rollers 43a to 43d can be improved.

[0065] Since the roller upper element 41 has an open upper portion so as to have a U-shape when viewed from the front-rear direction, the open portion is likely to deform so as to open when a load is applied to the main roller shafts 42a, 42b toward the outer periphery of the track belt 30. Therefore, by fixing the main roller shafts 42a, 42b to the element, the roller upper element 41 is made substantially box-shaped, and deformation of the upper element due to a load applied to the main rollers 43a to 43d from the open portion side of the U-shape is suppressed.

[0066] In the endless track device 1 according to the present invention, the roller element 40 is provided with guide rollers 45a, 45b on the inner circumference side of the rail 20. Therefore, compared to the case where a sliding plate is provided on the guide member on the inner circumference side of the rail as described in Patent Document 2, the running resistance is less likely to increase even if the clearance between the guide member and the rail 20 is narrowed. This structure allows the clearance between the guide rollers 45a, 45b and the rail 20 to be narrowed, making it difficult for a large difference to occur between the left and right, and highly effective in suppressing tilt of the roller element 40 in the roll direction. Therefore, the load applied to the main rollers 43a to 43d can be easily distributed, and concentrated wear on any one of the main rollers 43a to 43d can be prevented.

[0067] Furthermore, in the endless track device 1 according to the present invention, because the track belt 30 is made up of elements, even if one element is damaged, the damaged element can be easily replaced, making it easy to maintain. In particular, the track plate 70, which is the ground contact part and is easily worn out by impact or wear, is a separate member from the lower element 60, so even if replacement becomes necessary due to damage, it can be replaced by removing only the track plate 70. In addition, the bolts B for fixing each element to the core belt 31 are protected by the track plate, so they are less likely to wear out.

[0068] Some track devices have a so-called boat-shape in which the central portion of the underside of the device is convex in order to improve turning performance. In that case, however, the contact area is reduced, making it difficult to improve the load-bearing capacity. In contrast, the endless track device 1 of the present invention has a flat bottom 21, so that the entire track plate 70 located on the underside of the device comes into contact with the ground, and the ground load can be distributed over the entire bottom 21, making it easy to improve the load-bearing capacity.

[0069] <Modification> In the above embodiment, the main rollers 43a to 43d provided in the roller element 40 were supported by independent main roller shafts 42a, 42b, but in implementing the present invention, the arrangement of the shafts supporting the main rollers 43a to 43d can be selected in accordance with the shape of the roller upper element 41.

[0070] In the above embodiment, the roller element 40 is provided with the guide rollers 45a, 45b as guides for the inner circumference side of the rail 20, but in the practice of the present invention, it is not necessarily required to provide the guide rollers 45a, 45b. For example, when the guide rollers 45a, 45b are sliding plates, it is possible to reduce costs compared to the guide rollers 45a, 45b.

[0071] In the above embodiment, the track shoe 70 is formed with the chamfer 77, but in the practice of the present invention, the shape of the track shoe 70 is not limited to this. For example, a track shoe 70 without the chamfer 77 may be used. Even in this case, the track plate 70 fixed to the roller element 40 can sandwich the track plate 70 fixed to the non-roller element 50, so that the load-bearing capacity and running performance on rough ground are not reduced.

[0072] In the above embodiment, the bottom 21 of the rail 20 had a flat shape, but in implementing the present invention, the bottom 21 does not necessarily have to have a flat shape, and the bottom 21 may be deformed in cases where turning performance is important.

[0073] In the above embodiment, the length of the reinforcing member 13 is such that it does not protrude beyond the range of the bottom 21, but in the practice of the present invention, the length of the reinforcing member 13 is not limited to the range of the bottom. If the length of the reinforcing member 13 were such that it protruded from the bottom 21, the rigidity of the rail 20 could be improved, so the length of the reinforcing member 13 may be selected depending on the application of the product on which the endless track device 1 is mounted.

[0074] In the above embodiment, the roller elements 40 and the rollerless elements 50 are arranged alternately in the track belt 30. However, in the practice of the present invention, it is not necessary to arrange them in a 1:1 ratio, and the number of roller elements 40 may be increased depending on the required load resistance.

[0075] In the above embodiment, a cart having a track device 1 mounted on the cart top plate has been described as an example, but the present invention can be used for other purposes besides the traveling device of a cart. For example, the present invention may be used for the traveling device of an agricultural robot or the like. [Explanation of symbols]

[0076] 1...Crawler track device, 2...Transport vehicle, 10...Frame, 13...Reinforcing member, 20...Rail, 21...Bottom, 30...Track belt, 31...Core belt, 40...Roller element, 41...Upper roller element, 42a, 42b...Main roller shaft, 43a to 43d...Main roller, 44a, 44b...Guide roller shaft, 45a, 45b...Guide roller, 50...Non-roller element, 51...Non-roller upper element, 60...Lower element, 70...Trapezoid, 76...Contact surface, 77...Chamfer

Claims

1. an annular rail including a bottom portion that is long in a horizontal direction, a first bent portion having one end connected to one end of the bottom portion and extending upward while curving, a second bent portion having one end connected to the other end of the bottom portion and extending upward while curving, and a circular portion connecting the other end of the first bent portion and the other end of the second bent portion; a circular track belt that covers the entire rail from the outer periphery along the rail's shape; The track belt is an endless track device that circulates along the rail, The track belt includes a circular core belt having longitudinal ends connected to each other, and a plurality of elements to which track shoes are fixed, The elements are attached around the entire circumference of the core belt at intervals such that a predetermined gap is formed between adjacent ones of the track shoes, An endless track device, wherein the predetermined gap has a width narrower than a thickness of the track plate.

2. The endless track device according to claim 1, characterized in that the elements attached to the track belt are alternating between first elements having a main roller on the inner peripheral side of the core belt that contacts the outer peripheral side of the rail, and second elements not having the main roller.

3. 2. The endless track device according to claim 1, wherein a reinforcing member having a length equal to or shorter than a length of the bottom portion is fixed to the inner periphery of the rail at the bottom portion.

4. 2. The track device of claim 1, wherein the bottom portion is flat in shape.

5. 3. The endless track device according to claim 2, wherein the track plate is chamfered between one end surface in the circulation direction and the ground contact surface and between the other end surface and the ground contact surface.

6. The endless track device according to claim 2, characterized in that the first element is provided with a guide roller that is located on the inner side of the rail when the main roller is located at the bottom and that has a gap of up to 0.5 mm formed between the guide roller and the inner surface of the rail.

7. The first element has at least one main roller shaft that is horizontal and perpendicular to the circulating direction of the track belt, on each side of the center of the circulating direction, The endless track device according to claim 2, wherein the main rollers are provided at least one on each side of the axial center of the main roller shaft.

8. A transport vehicle comprising the caterpillar track device according to any one of claims 1 to 7.

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