JP7500108B1 - Trolley - Google Patents

Abstract

[Problem] To easily solve the problem of a dolly deviating from its travel route. [Solution] A dolly 1 comprises a loading platform 2 for carrying luggage, a front running unit 3 and a rear running unit 4 rotatably attached to the bottom surface 2A of the loading platform, and a connecting rod 5 that diagonally connects the front running unit and the rear running unit. The connecting rod is configured so that its length can be adjusted while it is still attached. [Selected Figure] Figure 1

Description

This disclosure relates to a trolley.

Trolleys are used to transport cargo in factories and other places. Multiple trolleys are connected together and towed by a towing vehicle to transport a large amount of cargo at once. Some trolleys are also equipped with four-wheel steering so that they can travel along curved routes without going beyond the tracks as much as possible. These trolleys are equipped with a platform for carrying cargo, front and rear running wheels that are rotatably attached to the underside of the platform, and a connecting rod that diagonally connects the front and rear running wheels.

JP 2019-77388 A

When a relatively large number of these four-wheel steering bogies are connected together and towed in a straight line, the rear bogie may stray from the travel route. To solve this problem, the connecting rods of the rear bogies are replaced with ones of different lengths. However, replacing them does not necessarily solve the problem, and further replacement may be necessary. Also, the direction and amount of displacement varies depending on the usage conditions, etc., making it difficult to determine a uniform length for the connecting rods. Of course, replacing them on site is not easy and is complicated.

The present disclosure was conceived in light of these circumstances, and its purpose is to provide a trolley that can easily solve the problem of the trolley deviating from its travel route.

According to one aspect of the present disclosure,
A platform for carrying luggage,
A front running mechanism and a rear running mechanism rotatably attached to the underside of the platform;
A connecting rod that diagonally connects the front running unit and the rear running unit;
Equipped with
The bogie is characterized in that the connecting rod is configured so that its length can be adjusted while it is in an attached state.

Preferably, the connecting rod is formed of a turnbuckle.

Preferably, the connecting rod is
A rod body extending linearly;
A right-handed threaded shaft that is screwed into one end of the rod body;
A left-handed screw shaft screwed to the other end of the rod body;
Equipped with.

Preferably, the rod body has
A hollow pipe;
a right-handed nut and a left-handed nut fixed to one end and the other end of the hollow pipe, respectively;
has.

Preferably, the rod body has a jig insertion hole into which a jig is inserted when the rod body is rotated.

Preferably, the connecting rod is
A lock nut for fixing the right-hand threaded shaft and the left-hand threaded shaft to the rod main body,
A coupling member fixed to each of the right-hand threaded shaft and the left-hand threaded shaft;
Equipped with.

Preferably, the lock nuts are threadedly engaged with the right-hand threaded shaft and the left-hand threaded shaft, respectively.

Preferably, the joint member is formed by a joint plate that is sandwiched and fixed between the right-hand threaded shaft and the left-hand threaded shaft,
The front traveling unit and the rear traveling unit have a pair of clamping plates that sandwich the joint plate,
The joint plate and the clamping plate have a connecting shaft insertion hole,
When a connecting shaft is inserted into the connecting shaft insertion hole, the joint plate is rotatably connected to the clamping plate.

Preferably, the front running gear has a front connection portion for connecting the connecting rod to one of the right side and the left side at the rear end thereof,
The rear running mechanism has a rear connection portion at the other of the right and left sides at its front end portion for connecting the connecting rod.

Preferably, the platform has a front pivot shaft and a rear pivot shaft protruding from a lower surface thereof,
The front running unit and the rear running unit have a front swivel hole and a rear swivel hole into which the front swivel shaft and the rear swivel shaft are rotatably inserted, respectively.

Preferably, the front running device has a traction member extending forward,
The platform has an engagement portion with which the towing member of a following carriage is engaged.

This disclosure makes it easy to solve the problem of the cart straying from its travel route.

FIG. 2 is a plan view showing the bogie according to the present embodiment. FIG. 2 is a side view showing the bogie according to the embodiment. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. 4 is a side view showing the connection between the connecting rod and the front running mechanism. FIG. 11 is a plan view for explaining the operation of the carriage. FIG. FIG. 11 is a plan view for explaining the cause of the problem. FIG. 11 is a plan view showing how the length of the connecting rod is adjusted.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Please note that the present disclosure is not limited to the following embodiments.

Figures 1 and 2 are a plan view and a side view showing the entire bogie according to this embodiment. The front-rear, left-right, top-bottom directions of the bogie 1 are as shown in the figures. Multiple bogies 1 can be connected together and are capable of four-wheel steering (4WS: 4 Wheel Steering).

The dolly 1 comprises a platform 2 for carrying luggage, a front running unit 3 and a rear running unit 4 rotatably attached to the underside 2A of the platform 2, and a connecting rod 5 that diagonally connects the front running unit 3 and the rear running unit 4. The connecting rod 5 of this embodiment is characterized in that it is configured so that its length can be adjusted while still attached.

Figures 3 and 4 are a plan view and a side view showing the loading platform 2 alone. The loading platform 2 is constructed by assembling ordinary steel materials (such as L-shaped steel), steel pipe materials (such as square pipes), steel plates, etc., by welding. The loading platform 2 is formed symmetrically from front to back and from left to right. The cargo that can be placed on the loading platform 2 is, for example, a plastic or metal pallet carrying products.

The loading platform 2 is formed in a quadrilateral, particularly a square, shape in plan view (Fig. 3). The loading platform 2 has a loading platform frame 6 formed in a quadrilateral shape in plan view, and support plates 7 provided on the upper surface of the four corners of the loading platform frame 6, front, rear, left and right, on which luggage is placed. The loading platform 2 also has restriction plates 8 provided on the four corners of the loading platform frame 6, front, rear, left and right. The restriction plates 8 protrude slightly upward from the support plates 7, and catch on luggage attempting to slide off the support plates 7 to prevent the luggage from sliding off. The restriction plates 8 are formed in an L-shape in plan view, and are attached to the front, rear, left and right side portions of the loading platform frame 6.

The loading platform 2 has a front swivel shaft 9 and a rear swivel shaft 10 that protrude downward from its underside 2A. The front swivel shaft 9 and the rear swivel shaft 10 are formed by solid shafts with a circular cross section that extend in the vertical direction, and are fixed to the front fixed plate 9A and the rear fixed plate 10A of the loading platform frame 6 in a penetrating state, respectively. The front swivel shaft 9 and the rear swivel shaft 10 are positioned in the center of the left-right width of the loading platform 2, and are spaced apart in the front-rear direction. The front swivel shaft 9 and the rear swivel shaft 10 are parts that attach the front running unit 3 and the rear running unit 4, respectively, so that they can swivel. Note that "swivel" refers to rotation around an axis that extends in the vertical direction (vertical axis or vertical axis).

The underside 2A of the loading platform 2 is provided with a front rolling plate 11 and a rear rolling plate 12, which come into contact with and roll on the support bearings 34 (see Figures 5 to 8) of the front running gear 3 and the rear running gear 4, which will be described later. The front rolling plate 11 and the rear rolling plate 12 are affixed to the underside of the loading platform frame 6 at positions around the front pivot shaft 9 and the rear pivot shaft 10. The front pivot shaft 9 and the rear pivot shaft 10 protrude downward beyond the front rolling plate 11 and the rear rolling plate 12.

The loading platform 2 has an engagement portion 13 on its rear surface 2B with which the towing member (described later) of the following dolly 1 engages. The engagement portion 13 has an engagement member 14 that is attached to the rear surface of the loading platform frame 6 and is U-shaped in side view (Fig. 4), a pin insertion hole 15 that passes vertically through the engagement member 14, and an engagement pin 16 that is inserted into the pin insertion hole 15 from above. A cushioning material 17 made of an elastic material such as rubber is attached to the inner surface of the engagement member 14 to prevent direct collision with the towing member. The engagement pin 16 has a circular cross section and a larger diameter handle 18 is provided at its upper end.

Figures 5 and 6 are a plan view and a side view showing the front running unit 3 alone. Note that the front running unit 3 and the rear running unit 4 are configured in almost the same way, so only the front running unit 3 will be described in detail, and the rear running unit 4 will be described in supplementary detail, focusing only on the differences.

The front running device 3 has a frame 20 extending in the left-right direction, and left and right casters 21, 22 attached to the underside of the frame 20. The frame 20 is formed in a rectangular frame shape whose left-right width is greater than its front-to-rear length in a plan view (Figure 5). The left and right casters 21, 22 are attached to the underside of the left and right ends of the frame 20. These casters 21, 22 are similar, so only the right caster 22 will be described in detail below.

The caster 22 has a rotatable wheel 23. In this embodiment, the caster 22 is formed as a fixed caster in which the wheel 23 does not rotate (i.e., does not swivel) around the vertical axis or the longitudinal axis.

The caster 22 has a base plate 26 fixed to the underside of the frame 20 by multiple (four) bolts 24 and nuts 25, a support leg 27 fixed to the base plate 26 and extending downward in a bifurcated shape, a suspension arm 29 sandwiched between the support legs 27 and attached by bolts 28 so as to be rotatable around a left-right axis (an axis extending in the left-right direction), a wheel 23 attached to the rear end of the suspension arm 29 by bolts 30 so as to be rotatable around the left-right axis, and a suspension spring 31 that urges the front end of the suspension arm 29 upward so as to press the wheel 23 against the road surface.

The front running gear 3 has a front swivel hole 32 into which the front swivel shaft 9 is rotatably inserted. The front swivel hole 32 is formed by a central hole in a center bearing 33 provided at the center of the front-to-rear length and left-to-right width of the frame 20. The center bearing 33 is formed by a ball bearing. A front thrust surface 32A that receives the main downward thrust load from the front fixed plate 9A of the loading platform 2 is formed around the center bearing 33. After assembly, the front thrust surface 32A is in slidable contact with the front fixed plate 9A.

In addition, the front running mechanism 3 has multiple (six) support bearings 34 arranged around the front swivel hole 32 and the front fixed plate 9A to supplementarily support the load of the loading platform 2. The support bearings 34 are also made of ball bearings. The support bearings 34 are rotatably mounted on the frame 20, one each in front and behind the center bearing 33, and two each on the left and right. The front and rear support bearings 34 are rotatable around the front-to-rear axis, and the left and right support bearings 34 are rotatable around the left-to-right axis. These support bearings 34 are arranged symmetrically in the front-to-rear and left-to-right directions with respect to the position of the front swivel hole 32. As can be seen from FIG. 6, these support bearings 34 protrude slightly upward from the frame 20.

To tow the trolley 1, the front running device 3 has a towing member 35 extending forward. The towing member 35 has a towing frame 36 that is fixed to the front portion of the frame 20 and has a U-shape in plan view, and a towing hook 38 that is rotatably attached to the front end of the towing frame 36 by a towing shaft 37. The towing hook 38 can rotate about the left and right axis, and is formed in a triangular shape in plan view as shown in FIG. 5. A pin insertion hole 38A is provided at the front end of the towing hook 38. A handle 39 is provided on the towing hook 38 for manually raising and lowering it or raising and lowering it.

The front running gear 3 has a front connection part 40 on the right side of its rear end for connecting the front end of the aforementioned connecting rod 5. The front connection part 40 has a pair of upper and lower clamping plates 41 fixed to the right side of the rear surface of the frame 20, and a connecting shaft insertion hole 42 formed vertically through these clamping plates 41.

Next, the rear running unit 4 will be described in more detail with reference to Figures 7 and 8. Here, parts similar to those of the front running unit 3 will be given the same reference numerals in the figures, with a few exceptions, and their description will be omitted. Also, the word "front" included in the names of the parts of the front running unit 3 will be replaced with "rear" for the rear running unit 4.

The rear running gear 4 has a rear swivel hole 43 into which the aforementioned rear swivel shaft 10 is rotatably inserted. This rear swivel hole 43 is also formed by a center bearing 33 made of a ball bearing. Around this center bearing 33, a rear thrust surface 43A is formed that receives the main downward thrust load from the rear fixed plate 10A of the loading platform 2. After assembly, the rear thrust surface 43A is in slidable contact with the rear fixed plate 10A.

The rear running gear 4 has a rear connection part 44 on the left side of its front end for connecting the rear end of the connecting rod 5 mentioned above. Like the front connection part 40, the rear connection part 44 also has a pair of clamping plates 41 and a connecting shaft insertion hole 42.

The rear running device 4 is not provided with a traction member 35.

Figures 9 and 10 are a plan view and a side view showing the connecting rod 5 alone. The symbol C represents the central axis of the connecting rod 5. Unless otherwise specified, the axial direction, radial direction, and circumferential direction based on the central axis C will be simply referred to as the axial direction, radial direction, and circumferential direction below.

For convenience, the axial end located on the right side of the figure is referred to as the front side, and the other axial end located on the left side of the figure is referred to as the rear side.

With some exceptions, the connecting rod 5 is constructed symmetrically front to back.

As mentioned above, the connecting rod 5 is configured so that its length can be adjusted while it is attached. More specifically, the connecting rod 5 is configured as a turnbuckle. The connecting rod 5 comprises a rod body 51 that extends linearly in the axial direction, a right-handed threaded shaft 52 that is screwed and attached to the front end (one end) of the rod body 51, and a left-handed threaded shaft 53 that is screwed and attached to the rear end (other end) of the rod body 51. In other words, the connecting rod 5 has reverse threads on both ends of the rod body 51. The rod body 51, the right-handed threaded shaft 52, and the left-handed threaded shaft 53 are arranged coaxially with the central axis C.

As is well known, a right-handed thread is a thread that advances toward the opposing thread when turned to the right. Conversely, a left-handed thread is a thread that advances toward the opposing thread when turned to the left.

The rod body 51 has a hollow pipe 54 which forms its basic part, and a right-handed nut 55 and a left-handed nut 56 which are fixed to the front and rear ends of the hollow pipe 54, respectively. The hollow pipe 54 is made of a steel pipe with a circular cross section. The right-handed nut 55 and the left-handed nut 56 are coaxially arranged on the front and rear end faces of the hollow pipe 54, sandwiching plate rings 55A and 56A, and are fixed by welding.

As will be described in detail later, the rod body 51 is rotated when adjusting the length of the connecting rod 5. To facilitate this rotation of the rod body 51, the rod body 51 is provided with a jig insertion hole 57 into which a jig or tool is inserted. The jig insertion hole 57 is formed by a circular hole provided on the front and rear sides of the hollow pipe 54 and penetrating the hollow pipe 54 in the radial direction.

In the axial direction of the connecting rod 5, the direction toward the longitudinal center C1 of the rod body 51 is called the axial inner direction, and the direction away from the longitudinal center C1 of the connecting rod 5 is called the axial outer direction. The longitudinal center C1 of the rod body 51 refers to the position that divides the length of the rod body 51 in half.

The base ends of the right-hand threaded shaft 52 and the left-hand threaded shaft 53, which are located on the axially inner side, are screwed into the right-hand threaded nut 55 and the left-hand threaded nut 56 and inserted into the hollow pipe 54. On the other hand, the remaining or tip end portions of the right-hand threaded shaft 52 and the left-hand threaded shaft 53, which are located on the axially outer side of the right-hand threaded nut 55 and the left-hand threaded nut 56, are not inserted into the hollow pipe 54 and are exposed to the outside.

Lock nuts 58, 59 and coupling members 60, 61 are attached to this tip end portion. The lock nuts 58, 59 are used to secure the right-hand threaded shaft 52 and the left-hand threaded shaft 53 to the rod body 51, and are screwed onto the right-hand threaded shaft 52 and the left-hand threaded shaft 53, respectively. The coupling members 60, 61 are used to connect the connecting rod 5 to the aforementioned front connection part 40 and rear connection part 44, respectively, and are fixed to the right-hand threaded shaft 52 and the left-hand threaded shaft 53.

Naturally, the lock nut 58 screwed onto the right-hand threaded shaft 52 has a right-hand female thread, and the lock nut 59 screwed onto the left-hand threaded shaft 53 has a left-hand female thread.

In this embodiment, a flat washer 58A and a spring washer 58B are attached between the lock nut 58 and the right-hand thread nut 55. A flat washer 59A and a spring washer 59B are attached between the lock nut 59 and the left-hand thread nut 56. However, at least one of the flat washer and the spring washer may be omitted.

For example, when fixing the right-hand threaded shaft 52 to the rod body 51, the lock nut 58 on the right-hand threaded shaft 52 is rotated clockwise and the lock nut 58 is tightened toward the right-hand threaded nut 55. This locks the rotation of the right-hand threaded shaft 52 relative to the rod body 51, and the right-hand threaded shaft 52 is fixed so that it cannot move relative to the rod body 51. The same is true for the left-hand threaded shaft 53, except that the rotation direction of the lock nut 59 is reversed.

The lock nut 58 in this embodiment is made of a nut with an anti-loosening function, such as a U-nut or nylon nut. This makes it possible to prevent the lock nut 58 from loosening. On the other hand, the right-hand thread nut 55 and the left-hand thread nut 56 are made of general-purpose nuts that do not have an anti-loosening function. This means that the anti-loosening function does not provide resistance when adjusting the length, and the rod body 51 can be rotated smoothly.

The joint members 60, 61 are formed by joint plates 62, 63 that are sandwiched and fixed between the right-hand threaded shaft 52 and the left-hand threaded shaft 53, respectively. The joint plates 62, 63 are formed in a rectangular shape whose front-to-rear length is longer than its left-to-right width in a plan view (Figure 9). The axially inner base ends of the joint plates 62, 63 are inserted into slits 64, 65 formed in the axially outer tip faces of the right-hand threaded shaft 52 and the left-hand threaded shaft 53, and welded to the right-hand threaded shaft 52 and the left-hand threaded shaft 53. The axially outer tip ends of the joint plates 62, 63 are provided with connecting shaft insertion holes 66, 67.

Next, we will explain how to assemble the trolley 1.

First, prepare a connecting rod 5 whose length has been adjusted to a predetermined standard length L0 (for example, 1000 mm). At this time, as shown in FIG. 9, the distance between the front and rear connecting shaft insertion holes 66, 67 is set to the length L of the connecting rod 5, and this length L is adjusted to the standard length L0. The method of length adjustment will be explained in detail later, but in this embodiment, the length can be adjusted by simply rotating the rod body 51 while restricting the rotation of the right-hand threaded shaft 52 and the left-hand threaded shaft 53, which is very convenient. The lock nuts 58, 59 are tightened, and the length of the connecting rod 5 is fixed to the standard length L0.

Next, the front and rear ends of the connecting rod 5 are connected to the front running unit 3 and the rear running unit 4, respectively. For example, in the case of the front side, as shown in FIG. 11, the front joint member 60 of the connecting rod 5, i.e., the joint plate 62, is inserted between a pair of clamping plates 41 at the front connection part 40 of the front running unit 3. Then, the connecting bolt 68 forming the connecting shaft is inserted from above into the connecting shaft insertion holes 42, 66 of the clamping plate 41 and the joint plate 62. A lock nut 70 having a loosening prevention function is tightened on the threaded part 69 of the connecting bolt 68 protruding downward to prevent the connecting bolt 68 from coming loose. As a result, the joint plate 62 is connected to the clamping plate 41, i.e., the front end of the connecting rod 5 is connected to the front running unit 3 so as to be rotatable or pivotable around the vertical axis.

The same is true for the rear side. With reference to Figures 7 to 10, the rear joint member 61 of the connecting rod 5, i.e., the joint plate 63, is inserted between a pair of clamping plates 41 at the rear connection part 44 of the rear running unit 4. Then, the connecting bolt 68 forming the connecting shaft is inserted from above into the connecting shaft insertion holes 42, 67 of the clamping plate 41 and the joint plate 63. A lock nut 70 with an anti-loosening function is tightened on the threaded part 69 of the connecting bolt 68 protruding downward to prevent the connecting bolt 68 from coming loose. This connects the joint plate 63 to the clamping plate 41, i.e., the rear end of the connecting rod 5 to the rear running unit 4, so that it can rotate or swing around the vertical axis.

When the connecting rod 5 is connected to the front and rear running gears 3 and 4 in this way, as shown in FIG. 1, the front and rear running gears 3 and 4 are diagonally connected by the connecting rod 5 in a plan view. Here, "diagonally connected" means that one of the right and left parts of the front running gear 3 is connected to the other of the right and left parts of the rear running gear 4, and the connecting rod 5 is arranged in a state inclined relative to the front-to-rear direction in a plan view. In this embodiment, the right part of the front running gear 3 is connected to the left part of the rear running gear 4, but this can also be reversed.

Next, as shown in Figures 1 and 2, the loading platform 2 is placed on the front running unit 3 and the rear running unit 4. At this time, the front swivel shaft 9 and the rear swivel shaft 10 of the loading platform 2 are rotatably inserted from above into the front swivel hole 32 (center bearing 33) of the front running unit 3 and the rear swivel hole 43 (center bearing 33) of the rear running unit 4, respectively. As a result, the front fixed plate 9A of the loading platform 2 comes into slidable contact with the front thrust surface 32A of the front running unit 3, and the rear fixed plate 10A of the loading platform 2 comes into slidable contact with the rear thrust surface 43A of the rear running unit 4. The main downward load of the loading platform 2 is then supported by the front running unit 3 and the rear running unit 4.

At the same time, the front rolling plate 11 and the rear rolling plate 12 of the loading platform 2 approach or come into contact with the support bearings 34 of the front running unit 3 and the rear running unit 4. Here, in terms of design, when the front swivel shaft 9 and the rear swivel shaft 10 of the loading platform 2 are inserted into the front swivel hole 32 of the front running unit 3 and the rear swivel hole 43 of the rear running unit 4 to place the loading platform 2, a small gap is formed between the front rolling plate 11 and the rear rolling plate 12 and the support bearing 34, so that the front rolling plate 11 and the rear rolling plate 12 do not come into contact with the support bearing 34. However, in reality, due to play, weight imbalance, etc., the loading platform 2 in the placed state is slightly tilted from the horizontal direction. At this time, the support bearings 34 that exist in the tilted direction come into contact with the front rolling plate 11 and/or the rear rolling plate 12, and supplementarily support the weight of the loading platform 2.

Once the loading platform 2 is placed in this way, the dolly 1 is completed. The dolly 1 can be towed forward by pulling the towing hook 38 of the towing member 35 with a towing vehicle or by hand.

As shown in FIG. 2, when the bogies 1 are coupled, the towing member 35 of the trailing bogie on the left side (rear side) outside the figure is engaged with the engagement part 13 of the bogie 1 shown in the figure. At this time, the front end of the towing hook 38 of the trailing bogie is inserted inside the engagement member 14 of the bogie 1, and the engagement pin 16 is inserted from above into the pin insertion hole 15 of the engagement member 14 and the pin insertion hole 38A of the towing hook 38 (see FIGS. 3 to 6). This causes the towing member 35 to engage with the engagement part 13, and the bogies 1 are coupled. A cushioning material 17 is provided on the inner surface of the engagement member 14, so damage caused by a direct collision between the towing hook 38 and the engagement member 14 can be prevented. The engagement pin 16 is formed long, so it is prevented from coming off by its own weight even when it is only inserted.

Next, the operation of the trolley 1 will be described with reference to Figure 12. For convenience, the loading platform 2 is omitted from the trolley 1 shown in the figure.

Figure 12 (A) shows the cart 1 moving straight ahead, pulled from the front by a traction force F1 and moving straight ahead. At this time, the direction D1 of the front running unit 3 and the direction D2 of the rear running unit 4 are both forward facing and in the same direction. The front running unit 3 moving straight ahead pulls the rear running unit 4 via the connecting rod 5, causing the rear running unit 4 to move straight ahead. This allows the cart 1 to move smoothly along the straight track R1 that extends in the fore-and-aft direction.

Figure 12 (B) shows the time of turning left. At this time, the traction force F2 is applied from the front left to the bogie 1, causing it to turn toward the front left. At this time, the direction D1 of the front running unit 3 faces the front left. Then, the right side of the front running unit 3 pulls the left side of the rear running unit 4 via the connecting rod 5, causing the direction D2 of the rear running unit 4 to face the front right. In other words, the front running unit 3 and the rear running unit 4 are steered so that they face in opposite directions, thereby achieving four-wheel steering in opposite phases. This allows the front running unit 3 and the rear running unit 4 to turn smoothly along the curved track R2 that curves to the left.

Figure 12 (C) shows the time of turning right. At this time, the traction force F3 pulls the cart 1 from the front right, causing it to turn towards the front right. At this time, the direction D1 of the front running unit 3 faces right and forward. Then, the right side of the front running unit 3 pushes the left side of the rear running unit 4 via the connecting rod 5, so the direction D2 of the rear running unit 4 faces left and forward. The front running unit 3 and the rear running unit 4 are then steered so that they face in opposite directions, achieving four-wheel steering in opposite phases. This allows the front running unit 3 and the rear running unit 4 to turn smoothly along the curved track R3 that curves to the right.

When the dolly 1 turns, the front running gear 3 and the rear running gear 4 turn around the front pivot shaft 9 and the rear pivot shaft 10 relative to the platform 2. At this time, the front thrust surface 32A of the front running gear 3 slides in the turning direction on the front fixed plate 9A of the platform 2, and the rear thrust surface 43A of the rear running gear 4 slides in the turning direction on the rear fixed plate 10A of the platform 2.

In addition, the support bearings 34 of the front running gear 3 and the rear running gear 4 roll in the turning direction along the undersides of the front rolling plate 11 and the rear rolling plate 12 of the loading platform 2. This allows the front running gear 3 and the rear running gear 4 to turn smoothly while the load of the loading platform 2 is supported by the support bearings 34.

As mentioned above, when a relatively large number of four-wheel steering bogies are connected together and towed in a straight line, the rear bogie may stray from the travel route. To solve this problem, the connecting rods of the rear bogies are replaced with ones of a different length. However, replacing them does not necessarily solve the problem, and further replacement may be necessary. Also, the direction and amount of displacement varies depending on the usage conditions, etc., making it difficult to determine a uniform length for the connecting rods. Of course, replacing them on site is not easy and is complicated.

This problem will be explained in detail below. Figure 13 shows a case where a relatively large number of bogies 1 of this embodiment are connected. In this embodiment, the number of connected bogies is seven, and the bogies 1 are numbered, starting from the front, as car No. 1 (#1), car No. 2 (#2), ... car No. 7 (#7). A test was conducted in which the leading car No. 1 was pulled by a towing vehicle, and the seven connected bogies 1 in total were driven straight forward.

The test results showed that the rear bogie 1 (for example, cars 5 to 7) had a problem with deviating from the running route. In other words, there was no problem when there were only a few cars connected, but problems tended to occur when there were a large number of cars connected.

Even if the deviation from the driving route of one vehicle is small, when two, three, etc. are coupled together, the deviation accumulates and becomes greater the further back the vehicle is. This is one of the reasons problems occur when many vehicles are coupled together.

Figure 14 is a diagram to easily explain the cause of the problem. Again, for convenience, the loading platform 2 is omitted.

First, Figure 14 (A) shows an ideal trolley 1 in which no misalignment occurs. When this trolley 1 travels straight, the direction D1 of the front running unit 3 and the direction D2 of the rear running unit 4 face straight ahead. Therefore, the trolley 1 travels forward in a straight line accurately along the linear track R1.

However, due to dimensional variations between individual items, the trolley 1 is not always in an ideal state. As a result, misalignment occurs in the trolley 1.

Figure 14 (B) shows a trolley 1 that has a problem with misalignment to the right. When this trolley 1 moves straight, the direction D1 of the front running gear 3 faces straight ahead, but the direction D2 of the rear running gear 4 faces to the right front. Therefore, the rear running gear 4 tries to move towards the right front, and as a result, the trolley as a whole moves straight ahead while misaligned to the right from the straight track R1.

Figure 14 (C) shows the opposite problem of a bogie 1 that deviates to the left. When this bogie 1 moves straight, the direction D1 of the front running gear 3 faces straight ahead, but the direction D2 of the rear running gear 4 faces to the left front. Therefore, the rear running gear 4 tries to move toward the left front, and as a result, the bogie as a whole moves straight ahead while deviating to the left from the straight track R1.

To solve this problem of misalignment, it is common to replace the connecting rod (shown by the reference symbol 5 for convenience) of the bogie 1 with one of a different length. For example, in the case of a bogie 1 that is misaligned to the right as shown in FIG. 14(B), replacing the connecting rod 5 with a longer one will correct the orientation D2 of the rear running unit 4 toward the left, making it closer to facing forward. Also, in the case of a bogie 1 that is misaligned to the left as shown in FIG. 14(C), replacing the connecting rod 5 with a shorter one will correct the orientation D2 of the rear running unit 4 toward the right, making it closer to facing forward.

However, replacing the rods does not necessarily solve the problem, and you may be forced to replace them again. Also, the direction and amount of misalignment varies depending on the usage conditions, making it difficult to determine a uniform length for the connecting rods. Of course, replacing the rods on site is not easy and is complicated.

In this embodiment, the connecting rod 5 is configured so that its length can be adjusted while it is still attached. This allows the length of the connecting rod 5 to be adjusted while it is still attached, without having to be removed from the trolley 1. Therefore, by adjusting the length of the connecting rod 5, the direction D2 of the rear running unit 4 can be corrected, bringing it closer to facing forward, and improving the straightness of the trolley 1. This makes it easy to solve the problem of the trolley 1 deviating from its travel route.

In particular, as shown in FIG. 13, when a relatively large number of bogies 1 are connected, by adjusting the length of the connecting rods 5 of the rear bogies 1 that tend to deviate from the travel route, it is possible to reliably keep all of the bogies 1 within the travel route even when a large number of bogies are connected.

In particular, in this embodiment, the connecting rod 5 is configured with a turnbuckle as described above. This makes it extremely easy to adjust the length of the connecting rod 5.

As shown in Figures 9 and 10, when adjusting the length of the connecting rod 5, the lock nuts 58, 59 are loosened so that the right-hand threaded shaft 52 and the left-hand threaded shaft 53 can rotate freely relative to the right-hand threaded nut 55 and the left-hand threaded nut 56. Then the rod body 51 is rotated. At this time, it is very convenient because a rod-shaped jig such as a screwdriver can be inserted into the jig insertion hole 57 of the rod body 51 to rotate it. However, there is no problem with rotating it by hand.

As shown in FIG. 1, a rectangular (square) opening 71 is provided in the center of the loading platform 2, which exposes almost the entire connecting rod 5, particularly the lock nuts 58, 59 and the rod body 51. This opening 71 allows access to the connecting rod 5 from above, making it easy to adjust the length of the connecting rod 5.

As shown in FIG. 11, the coupling members 60, 61 fixed to the right-hand threaded shaft 52 and the left-hand threaded shaft 53 are connected to the front connection part 40 and the rear connection part 44 of the front running unit 3 and the rear running unit 4. Therefore, the rotation of the right-hand threaded shaft 52 and the left-hand threaded shaft 53 is restricted, and the right-hand threaded shaft 52 and the left-hand threaded shaft 53 do not rotate even if the rod body 51 is rotated. Therefore, when the rod body 51 is rotated, the right-hand threaded shaft 52 and the left-hand threaded shaft 53 simultaneously move forward and backward relative to the right-hand threaded nut 55 and the left-hand threaded nut 56. Therefore, the length of the connecting rod 5 can be adjusted extremely easily just by rotating the rod body 51.

As shown in Figure 9, for example, suppose the rod body 51 is rotated left (counterclockwise) as shown by arrow a when viewed from the front. This results in a right-handed (clockwise) rotation for the front right-handed threaded shaft 52, as shown by arrow b, entering the right-handed threaded nut 55. On the other hand, the rear left-handed threaded shaft 53 also rotates right (left-handed when viewed from behind) as shown by arrow c, entering the left-handed threaded nut 56. This shortens the length of the connecting rod 5.

Conversely, if the rod body 51 is rotated clockwise as viewed from the front, the front right-hand threaded shaft 52 rotates counterclockwise relatively, and the rear left-hand threaded shaft 53 also rotates counterclockwise relatively (clockwise as viewed from the rear), and the length of the connecting rod 5 is lengthened.

Once the length of the connecting rod 5 has been adjusted in this way, the lock nuts 58, 59 are loosened to complete the process. In the end, the length of the connecting rod 5 can be adjusted in just three steps - loosening the lock nuts 58, 59, rotating the rod body 51, and then loosening the lock nuts 58, 59 - which is extremely convenient and ideal for adjustments on-site. Even if the problem is not resolved after adjustment, it can be easily adjusted again, eliminating the need for complexity. In other words, each trolley 1 can be set up easily and quickly to suit the usage situation.

Figure 15 shows how to adjust the length of the connecting rod 5 in the bogie 1 of this embodiment. All of Figures 15 (A) to (C) show the state when the bogie 1 is moving straight forward. The left and right boundary lines of the ideal traveling route are indicated by AL and AR. The distance between these boundary lines AL and AR is equal to the left and right width of the bogie 1.

Figure 15 (A) shows the state when the bogie 1 deviates to the left from the travel route. The amount of deviation is relatively large, B1, and the length of the connecting rod 5 at this time is considered to be too long. For example, the upper limit value Bmax of the amount of deviation is 50 mm, and the above amount of deviation B1 is 60 mm, exceeding the upper limit value Bmax.

Based on this result, the length of the connecting rod 5 is adjusted to be shorter. The result at that time is shown in Figure 15 (B). In Figure 15 (B), the bogie 1 is shifted to the right from the travel route, but the amount of shift is smaller, B2 = 30 mm, which is less than the upper limit value Bmax. Therefore, the length of the connecting rod 5 at this time is considered to be roughly appropriate.

On the other hand, Figure 15(C) shows the result when the length of the connecting rod 5 is made too short, based on the result of Figure 15(A). In Figure 15(C), the bogie 1 is relatively significantly deviated to the right from the travel route, and the amount of deviation B3 is 75 mm, exceeding the upper limit value Bmax. Therefore, in this case, it is appropriate to readjust the length of the connecting rod 5 to make it slightly longer, and to keep the amount of deviation within the upper limit value Bmax.

The length of the connecting rod 5 in this embodiment can be adjusted within a range of ±ΔL (e.g., 10 mm) from the reference length L0 (e.g., 1000 mm). ΔL is a predetermined adjustment range.

However, if the front-to-rear length of the loading platform 2 is changed and the distance between the front running unit 3 and the rear running unit 4 is changed, it is necessary to prepare a connecting rod 5 with a different standard length L0. Even in this case, in this embodiment, it is only necessary to change to a hollow pipe 54 with a different length, so that a connecting rod 5 of a different size can be easily produced at low cost, and versatility is improved.

Although the embodiments of the present disclosure have been described in detail above, there are many other possible embodiments and variations of the present disclosure.

(1) For example, the right-hand threaded shaft 52 and the left-hand threaded shaft 53 of the connecting rod 5 may be reversed in position. Accordingly, the right-hand threaded nut 55, the left-hand threaded nut 56, and the lock nuts 58, 59 may be reversed in position.

(2) A jig engagement portion for engaging a jig or tool may be provided on the outer periphery of the rod body 51 of the connecting rod 5. For example, a hexagonal portion, a square portion, or a facing portion for engaging a wrench may be provided on the outer periphery of the rod body 51 as the jig engagement portion.

(3) The rod body 51 of the connecting rod 5 may be composed of a solid shaft and right-hand and left-hand female threads formed by female thread machining at both ends of the solid shaft.

(4) The arrangement of the front connection part 40 and the rear connection part 44 to which the connecting rod 5 is connected may be reversed.

(5) General-purpose nuts without a locking function may be used for the lock nuts 58 and 59. If possible, the lock nuts 58 and 59 may be omitted.

The embodiments of the present disclosure are not limited to the above-mentioned embodiments, and all modifications, applications, and equivalents encompassed within the concept of the present disclosure as defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be interpreted in a limited manner, and may be applied to any other technology that falls within the scope of the concept of the present disclosure.

Reference Signs List 1: Carriage 2: Loading platform 2A: Underside 3: Front running mechanism 4: Rear running mechanism 5: Connecting rod 9: Front swivel shaft 10: Rear swivel shaft 13: Engagement portion 32: Front swivel hole 35: Towing member 40: Front connection portion 41: Clamping plates 42, 46: Connecting shaft insertion hole 43: Rear swivel hole 44: Rear connection portion 51: Rod body 52: Right-hand threaded shaft 53: Left-hand threaded shaft 54: Hollow pipe 55: Right-hand threaded nut 56: Left-hand threaded nut 57: Jig insertion hole 58, 59: Lock nut 60, 61: Joint member 62, 63: Joint plate 68: Connecting bolt

Claims (9)

A platform for carrying luggage,
A front running mechanism and a rear running mechanism rotatably attached to the underside of the platform;
A connecting rod that diagonally connects the front running unit and the rear running unit;
A cart comprising:
The connecting rod is constituted by a turnbuckle whose length can be adjusted while it is in an attached state,
The connecting rod is
A rod body extending linearly;
A right-handed threaded shaft that is screwed into one end of the rod body;
A left-handed screw shaft screwed to the other end of the rod body;
Lock nuts on one end and the other end of the right-hand threaded shaft and the left-hand threaded shaft are fixed to the rod main body, respectively;
Equipped with
The loading platform is provided with an opening for exposing the rod body and the lock nuts on one end side and the other end side when the cart is moving straight.
A trolley characterized by: The rod body is
A hollow pipe;
a right-handed nut and a left-handed nut fixed to one end and the other end of the hollow pipe, respectively;
The dolly of claim 1 , further comprising: The carriage according to claim 1 , wherein the rod body has a jig insertion hole into which a jig is inserted when the rod body is rotated. The connecting rod includes coupling members fixed to the right-hand threaded shaft and the left-hand threaded shaft, respectively.
The dolly according to claim 1 . The bogie according to claim 1 , wherein the lock nut is screwed onto each of the right-handed threaded shaft and the left-handed threaded shaft. The joint member is formed by a joint plate that is sandwiched and fixed between the right-hand threaded shaft and the left-hand threaded shaft,
The front traveling unit and the rear traveling unit have a pair of clamping plates that sandwich the joint plate,
The joint plate and the clamping plate each have a connecting shaft insertion hole,
The bogie according to claim 4 , wherein the joint plate is rotatably connected to the clamping plate by inserting a connecting shaft into the connecting shaft insertion hole. the front running mechanism has a front connection portion for connecting the connecting rod to one of the right side and the left side at a rear end portion thereof,
The bogie according to claim 1 , wherein the rear running mechanism has a rear connection portion for connecting the connecting rod to the other of the right and left sides at a front end portion thereof. The platform has a front pivot shaft and a rear pivot shaft protruding from a bottom surface thereof,
The bogie according to claim 1 , wherein the front running unit and the rear running unit have a front swivel hole and a rear swivel hole into which the front swivel shaft and the rear swivel shaft are rotatably inserted, respectively. The front traveler has a traction member extending forward,
The dolly according to claim 1 , wherein the platform has an engagement portion with which the towing member of a following dolly is engaged.

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