JP2004074997A - Truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a truck which is used not only as a four-wheel steering type truck but also as a hand truck, and improves the operability when the truck is used as a hand truck. <P>SOLUTION: A four-wheel steering mechanism 30 is switched in a steerable condition and a non-steerable condition by drawing/inserting a lock pin 41 from/in a lock plate 42 provided on the four-wheel steering mechanism 30 side and a lock plate 43 provided on a cargo bed 11 side. A front wheel 13 is formed of a universal caster, and the front wheel 13 is switched in an unlocked condition and a non-turnable locked condition by drawing/inserting the lock pin of a switching lever provided on the front wheel 13 from/in a locking member provided on a steering bar 31. According to the switching system, the truck is used not only as a four-wheel steering type truck but also as a hand truck. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a truck with a four-wheel steering (4WS) mechanism connected to, for example, a tow truck (tractor) and used for carrying cargo, and more particularly to a bogie that can be separated from the tow truck and used as a hand cart. .
[0002]
[Prior art]
BACKGROUND ART Conventionally, a bogie provided with a four-wheel steering mechanism is described in, for example, Patent Document 1. In Patent Literature 1, a cross member extending in the vehicle width direction is provided at front and rear portions of a lower surface of a loading platform, and a pair of left and right front wheels and rear wheels are individually steerably attached to the cross member. The left and right front wheels are connected to each other by a front steering link, and the left and right rear wheels are connected to each other by a rear steering link. Further, the front and rear steering links are connected by a crossbar such that the steering directions of the front wheels and the rear wheels are opposite to each other. A four-wheel steering bogie using the above link mechanism is connected to a towing vehicle via a towing lever constituting a steering wheel of the four-wheel steering mechanism in, for example, a factory or a warehouse, and is towed by the towing vehicle. Used in the form of When the towing vehicle changes the traveling direction, the towing lever is steered accordingly, and the directions of the front wheels and the rear wheels are changed. Thereby, the bogie can run following the towing vehicle.
[0003]
[Patent Document 1]
JP 2001-519287 A
[Problems to be solved by the invention]
The four-wheel steering trolley may be used as a hand trolley when separated from the towing vehicle. Therefore, in order to cope with the use as a hand cart, the cart is provided with a hand handle having a height suitable for the hand pushing operation, and the worker moves the cart by pushing or pulling the hand handle. . However, in the case of a four-wheel steering bogie, the direction of the front and rear wheels must be changed by steering the traction lever. In other words, there is a problem in that the push handle and the towing lever must be operated, and the operability is poor.
[0005]
The present invention has been made in view of the above-described conventional problems, and has as its object the purpose of being able to be used not only as a four-wheel steering cart but also as a cart. It is an object of the present invention to provide a technology capable of improving operability when using the device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a truck according to the present invention is configured as described in claims 1 to 4. The invention described in each of these claims is characterized in that two left and right first wheels are provided on one side of the lower surface of the bed having a handle for pushing and two wheels are provided on the other side of the lower surface of the bed. A truck equipped with a four-wheel steering mechanism capable of steering all of the wheels and having a tractor or a tractor that can be connected to another trolley as a steering handle. This technology can be used not only as a cart but also as a cart, and when used as a cart, operability can be improved.
[0007]
The truck according to claim 1 includes a steering state switching unit that switches the four-wheel steering mechanism between a steerable state and a steerable state, and at least one of the first wheel and the second wheel is provided. A swivel caster that can swivel about a vertical axis, and a swivel switching mechanism that switches between a locked state that disables swiveling of the swivel caster and an unlocked state that enables swiveling. It is characterized by.
According to the invention of claim 1 configured as described above, for example, when a bogie is used by being connected to a tow vehicle, a steering wheel as a tow device is connected to the tow vehicle, and the four-wheeled vehicle is operated by the steering state switching means. The steering mechanism is switched to the steerable state, and the swivel switching mechanism is further switched to the locked state by the turning switching mechanism. Therefore, at this time, the four-wheel steering mechanism functions as usual, and the bogie can run following the towing vehicle.
On the other hand, when used as a hand cart, the towing device is disconnected from the towing vehicle, the four-wheel steering mechanism is switched to the non-steerable state by the steering state switching means, and the swivel caster is switched to the unlocked state by the turning switching mechanism. This allows the swivel caster to be swiveled, so that the direction can be easily changed when the bogie is moved by gripping the push handle. Thereby, the operability at the time of use as a hand cart is improved, which contributes to an improvement in work efficiency.
[0008]
In the truck according to claim 2, the four-wheel steering mechanism is rotatably mounted on the lower surface of the loading platform around a vertical axis as a center of rotation, and the first steering member and the first steering member having first wheels mounted on both left and right sides. A second steering member to which two wheels are attached, a connecting member that connects the two steering members so as to rotate in opposite directions, and a first steering member and a second steering member. And a traction tool for rotating either one of them. According to the invention of claim 2 having such a configuration, a four-wheel steering mechanism having a simple structure can be provided.
[0009]
In this case, as described in claim 3, it is preferable that the steering state switching means is configured to fix or release the fixing tool from the carrier.
Further, as described in claim 4, the towing device is stored in a towing position in a horizontal position that can be connected to a towing vehicle or another bogie, and an upright position from the towing position along the hand pushing handle. It is preferable that the configuration is such that it is displaced between the position. According to such a configuration, the towing device can be effectively connected to the towing vehicle by displacing the towing device to the towing position in the horizontal posture, and in a use form as a hand cart, the towing device is moved to the storage position. By displacing, it can be set in a state where it does not hinder the pushing operation.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a four-wheel steering bogie according to an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a front view thereof. The carriage 10 according to the present embodiment includes a loading platform 11 formed as a main component of a rectangular iron plate whose longitudinal direction is the front-rear direction in a plan view, and a gate that is formed by bending a pipe or the like and stands upright on the front side of the loading platform 11. Shaped push handle 12, four wheels arranged on the front and rear lower surfaces of the loading platform 11, that is, two front wheels 13 arranged on the front left and right, and two rear wheels arranged on the rear left and right. 14 is provided. The front wheel 13 and the rear wheel 14 correspond to a first wheel and a second wheel in the present invention.
Steering bars 31, 32 are arranged on the front lower surface and the rear lower surface of the carrier 11, respectively. The front and rear steering bars 31, 32 extend in the vehicle width direction and have a central portion in the extending direction at the carrier. 11 is mounted rotatably around the vertical axis via bearings 31a and 32a, respectively, at the center in the vehicle width direction. Front wheels 13 are attached to left and right ends of the front steering bar 31, and rear wheels 14 are attached to left and right ends of the rear steering bar 32.
[0011]
The front wheel 13 includes a yoke 13a and wheels 13c rotatably supported on the yoke 13a via a shaft 13b. The yoke 13a is pivotally attached to the front steering bar 31 via a vertical shaft 13d. I have. The rear wheel 14 includes a yoke 14a and wheels 14c rotatably supported on the yoke 14a via a shaft 14b. The yoke 14a is fixed to a rear steering bar 32. That is, in the present embodiment, the front wheel 13 is constituted by a free caster, and the rear wheel 14 is constituted by a fixed caster.
[0012]
The swivel caster constituting the front wheel 13 is provided with a turning switching mechanism 20 for switching the turning of the front wheel 13 between a locked state and an unlocked state. As shown in the side view of FIG. 6, the turning switching mechanism 20 includes a switching lever 21 attached to the yoke 13a so as to be vertically rotatable, a lock pin 22 provided on the upper surface of the switching lever 21, and a steering mechanism. And a ring-shaped lock member 23 fixed to the lower surface of the bar 31. The lock member 23 is arranged so that its center coincides with the axis of the vertical shaft 13d, and has a lock groove 23a at one place on the circumferential end surface (lower surface).
Therefore, by turning the switching lever 21 upward and inserting the lock pin 22 into the lock groove 23a of the lock member 23, the turning of the front wheel 13 is locked, and the switching lever 21 is rotated downward to lock the lock pin 22. By pulling out from the groove 23a, the turning lock of the front wheel 13 can be released. That is, the front wheel 13 is switched between a locked state and an unlocked state by rotating the switching lever 21, and when switched to the locked state, becomes a fixed caster similarly to the rear wheel 14. However, the positions of the lock pin 22 and the lock groove 23a are set so that the front wheel 13 is locked when the wheel 13c is directed straight.
Although not shown, when the switching lever 21 is rotated, a spring is provided that reverses the biasing direction with the reference line P of the rotation range, for example, the center part as a boundary line, The switching lever 21 is configured to be biased and held at the rotated locked position or unlocked position.
[0013]
All of the front wheels 13 and the rear wheels 14 attached as described above are steered by the four-wheel steering mechanism 30. The four-wheel steering mechanism 30 includes the front and rear steering bars 31 and 32 described above, a cross bar 33 that connects the front and rear steering bars 31 and 32, a steering handle 34 attached to the front steering bar 31, and the like. ing. An end of the cross bar 33 is rotatably connected to, for example, a right joint plate 31b of the front steering bar 31 and a left joint plate 32b of the rear steering bar 32, and the steering bars 31, 32 are connected to each other. They are configured to rotate in opposite directions. Thus, when the four-wheel steering mechanism 30 according to the present embodiment operates the steering wheel 34 and rotates the front steering bar 31 around the vertical axis, the front wheel 13 and the rear wheel 14 It is configured to rotate, that is, rotate in the opposite phase. The front and rear steering bars 31 and 32 correspond to the first steering member and the second steering member according to the present invention, and the crossbar 33 corresponds to the connecting member according to the present invention.
[0014]
The steering handle 34 of the four-wheel steering mechanism 30 constitutes a traction lever as a front traction tool, and is attached to a handle support 35 formed on the front steering bar 31. As shown in FIGS. 4 and 5, the handle support portion 35 extends horizontally forward from the front central portion of the steering bar 31, and its extended end reaches forward from the front end surface of the carrier 11. A handle receiving portion 35a is formed on the upper surface of the extension end. The steering handle 34 is provided with a shaft portion 34b provided at a base end portion 34a of the steering handle 34 so as to be rotatable in a vertical direction with respect to the handle receiving portion 35a. 1 (a position shown by a solid line in FIG. 1) and a retracted position (a position shown by a two-dot chain line in FIG. 1) standing up from the towed position along the handle 12 for pushing. I have.
When the steering handle 34 is turned to the towing position, the base end portion 34a is held in a horizontal posture by abutting on the horizontal surface portion 35b of the handle receiving portion 35a. The portion 34a is configured to be held rearward at a predetermined angle by contacting a stopper 35c provided on the handle receiving portion 35a. The distal end of the steering handle 34 is provided with a pin hole 34c into which a drawbar pin that can be inserted and removed and that is attached to the rear of the towing vehicle 1 is inserted. Further, a rear traction tool is provided at a rear portion of the bogie 10 to connect a steering wheel of another bogie. The rear traction tool includes a drawbar bracket 36 fixed to the carrier 11 and a drawbar pin 37 that can be inserted into and removed from the drawbar bracket 36.
[0015]
Further, the bogie 10 is provided with a lock pin 41 as steering state switching means 40 for switching the four-wheel steering mechanism 30 between a steerable state and a steerable state. In the present embodiment, as shown in FIGS. 4 and 5, lock plates 42, 43 having pin holes 42a, 43a penetrating vertically are fixed to the rear surface of the handle receiving portion 35a and the front surface of the carrier 11. Have been. The mounting positions of the lock plates 42 and 43 are set such that the centers of the pin holes 42a and 43a coincide when the front wheel 13 and the rear wheel 14 face in the straight traveling direction. Therefore, in this state, the steering handle 34 can be locked to the carrier 11 by inserting the lock pin 41 into both the pin holes 42a and 43a. This state is a state where the four-wheel steering mechanism 30 cannot be steered, and a state where the lock pin 41 is pulled out from both the pin holes 42a and 43a is a steerable state.
In addition, a cylindrical pin holder 44 for storing the lock pin 41 extracted from the pin holes 42a and 43a is provided on the front surface of the carrier 11.
[0016]
The trolley 10 according to the present embodiment is configured as described above. Therefore, when used in connection with the towing vehicle 1, the lock pin 41 is pulled out from the pin holes 42a, 43a of the lock plates 42, 43, and the four-wheel steering mechanism 30 is switched to a steerable state. 44. Further, the switching lever 21 of the rotation switching mechanism 20 is rotated upward, the lock pin 22 is inserted into the lock groove 23a of the lock member 23, and the front wheel 13 is switched to a locked state in which the front wheel 13 cannot rotate. Then, the steering wheel 34 is rotated to the towing position in the horizontal posture and connected to the towing vehicle 1. FIG. 7 illustrates a state in which two trucks 10 are connected to the towing vehicle 1. When the switching is performed as described above, the four-wheel steering mechanism 30 functions as usual, and the front wheels 13 become the same fixed casters as the rear wheels 14, so that when the towing vehicle 1 travels, the traveling locus thereof The truck 10 is driven to follow.
[0017]
On the other hand, when the cart 10 is used as a hand cart, the lock pin 41 taken out from the pin holder 44 with the front wheel 13 and the rear wheel 14 directed straight ahead is inserted into the pin holes 42a, 43a of the lock plates 42, 42. The four-wheel steering mechanism 30 is switched to a steering disabled state. Further, the switching lever 21 of the rotation switching mechanism 20 of the front wheel 13 is rotated downward, the lock pin 22 is pulled out from the lock groove 23a of the lock member 23, and the front wheel 13 is switched to the unlocked state in which the front wheel 13 can freely rotate. Then, the steering handle 34 is rotated from the towing position in the horizontal posture to the storage position in the standing posture and stored. In this state, since the front wheel 13 is a swivel caster that can turn about the vertical axis 13d as a rotation axis, when the hand-push handle 12 is moved by gripping or pulling, the direction is easily changed in the same manner as a general bogie. It becomes a hand cart with good operability. Further, since the steering handle 34 is stored in an upright posture along the push handle 12, it does not hinder the cargo handling work by the push cart.
[0018]
As described above, the bogie 10 according to the present embodiment switches the four-wheel steering mechanism 30 to the steerable state or the non-steerable state, and correspondingly locks or turns the front wheel 13 about the vertical axis 13d. By switching to the unlocked state, the vehicle can be suitably used as a four-wheel steering vehicle when connected to the towing vehicle 1 and as a hand truck when disconnected from the towing vehicle 1.
[0019]
In addition, the four-wheel steering mechanism 30 of the present embodiment is configured such that the steering bars 31, 32 are rotatably mounted on the front and rear surfaces of the lower surface of the carrier 11 via bearings 31a, 32a, and the front wheels 13 and the rear wheels 14 are mounted thereon. The front and rear steering bars 31 and 32 are connected by a cross bar 33 so as to rotate in mutually opposite directions. Therefore, the structure of the four-wheel steering mechanism 30 is different from that of the four-wheel steering mechanism in which the front wheel and the rear wheel are individually steerably mounted on the carrier side, and the front wheel and the rear wheel can be steered by the link mechanism. Can be simplified.
[0020]
Note that the present invention is not limited to the above-described embodiment, and may be appropriately changed without departing from the gist of the present invention.
In the above-described embodiment, the lock pin 41 is inserted and removed from the lock plates 42 and 43 as the steering state switching means 40 for switching the four-wheel steering mechanism 30 to the steering disabled state or the steerable state. Then, for example, the steering handle 34 may be changed to a configuration in which the steering handle 34 is stored in the storage position and the hook is used to lock the steering handle 34 to the hand pushing handle 12.
Further, in the above-described embodiment, the front wheel 13 is constituted by the free caster with the turning switching mechanism 20, but the rear wheel 14 may be constituted by the free caster with the turning switching mechanism 20, or the front wheel 13 and the rear wheel 14 Both may be constituted by a swivel caster with a turning switching mechanism 20.
Further, the four-wheel steering mechanism 30 may be modified so that the front wheels 13 and the rear wheels 14 are individually steerably mounted on the carrier 11 side, and are steered by the link mechanism. In addition, when the four-wheel steering mechanism 30 is switched to the non-steerable state, the front wheel 13 is switched to an unlocked state in which the front wheel 13 can turn. When the four-wheel steering mechanism 30 is switched to the steerable state, the front wheel 13 turns. A configuration may be adopted in which the steering state switching means 40 of the four-wheel steering mechanism 30 and the turning switching mechanism 20 of the front wheel 13 are interlocked so as to switch to the impossible lock state, in which case the switching operation is simplified. it can.
[0021]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to use not only as a four-wheel steering cart but also as a cart, and to improve the operability when used as a cart. .
[Brief description of the drawings]
FIG. 1 is a side view of a truck according to an embodiment.
FIG. 2 is a plan view of the cart.
FIG. 3 is a front view of the cart.
FIG. 4 is a plan view showing a mounting portion of a steering wheel and a steering state switching unit.
FIG. 5 is a sectional view taken along line AA of FIG. 4;
FIG. 6 is a side view showing a turning switching mechanism.
FIG. 7 is a schematic diagram showing a mode in which the vehicle is used in connection with a towing vehicle as a four-wheel steering bogie.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Dolly 11 ... Carrying bed 12 ... Hand pushing handle 13 ... Front wheel (1st wheel)
14 ... rear wheel (second wheel)
20 turning switch mechanism 21 switching lever 22 lock pin 23 locking member 30 four-wheel steering mechanism 31 front steering bar (first steering member)
32: Rear steering bar (second steering member)
33 ... Crossbar (connecting member)
34 ... Steering wheel (traction tool)
40: steering state switching means 41: lock pin 42: lock plate 43: lock plate

Claims (4)

One side of the lower surface of the loading platform having the handle for pushing is provided with two left and right first wheels, and the other side of the lower surface of the loading platform is provided with two left and right two wheels. A bogie having a four-wheel steering mechanism that can steer wheels and has a towing tool or a towing device that can be connected to another bogie as a steering handle,
Steering state switching means for switching the four-wheel steering mechanism between a steerable state and a steerable state; and at least one of the first wheel and the second wheel is capable of turning around a vertical axis. A bogie comprising a swivel caster, and a swivel switching mechanism for switching between a locked state in which swiveling of the swivel caster is disabled and an unlocked state in which swiveling is enabled. 2. The truck according to claim 1, wherein the four-wheel steering mechanism is rotatably mounted on a lower surface of the loading platform with a vertical axis as a rotation center, and the first wheel is mounted on both left and right sides. 3. A second steering member to which the second steering wheel and the second wheel are attached, a connecting member that connects the two steering members so as to rotate in opposite directions, and a first steering member and a second steering member. And a trolley for rotating one of the steering members. The bogie according to claim 2, wherein the steering state switching unit is configured to fix or release the towing device with respect to the loading platform. The trolley according to claim 2 or 3, wherein the traction tool has a traction position in a horizontal position connectable to a traction vehicle or another trolley, and a posture standing upright from the traction position along the handle for pushing. A trolley, wherein the trolley is configured to be displaced between a stored position and a stored position.

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