JP2000211312A - Carrier vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier vehicle having no differential gear, permitting an easy change of direction of travel by hand in a condition where an electric motor or an engine thereof is stopped. SOLUTION: Upon engagement of a head portion 53b of a headed pin 53 with a bolt 66, a front wheel 2R starts to rotate together with a front axle 44 as indicated by an arrow 2. This permits a carrier vehicle to travel forward. As a result, the front wheel 2R can rotate as indicated by an arrow 3 keeping the front axle in a standstill. Namely, within the range of an angle θ (approximately 300 deg.) until the bolt 66 comes in contact with the head portion 53b, the front wheel can rotate counterclockwise. Since driving wheels can idle within a predetermined angle, turning or a change in direction of travel is permitted by idling the driving wheels. As a result, operability of the carrier vehicle can be greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transportation vehicle driven by an electric motor or an engine and having no differential mechanism between left and right wheels.

[0002]

2. Description of the Related Art With the spread of plastic greenhouses, melon cultivation has been actively performed even in cold regions.
Large greenhouse is 50m to allow for great harvest
It is as long as ｍ100 m, and mechanical power is required to move fertilizers, seedlings and crops. Conventionally, a tractor and a cultivator were used. However, since the prime mover was an internal combustion engine (gasoline engine, diesel engine), exhaust gas was trapped in the house, which was not preferable in terms of work environment hygiene. In addition, tractors and cultivators are basically agricultural machines suitable for outdoor work, and therefore have poor maneuverability in a small house.

[0003] Therefore, for example, the use of an "electric transporter" disclosed in Japanese Utility Model Publication No. 51-31502 was examined. As shown in FIG. 2 of the publication, this electric transporter connects the front left wheel 11 to a motor 4 via a chain and a sprocket.
, The front right wheel 11 ′ is driven by the electric motor 4 ′ via a chain and a sprocket, and the rear left and right wheels 17, 17 ′ are driven.
And an electric vehicle including batteries 15, 15 'between the front and rear wheels. By operating the electric motors 4 and 4 ′ by operating the switch box 16 (FIG. 1 in the publication), the left and right sides can be controlled independently, and the body can be turned.

[0004]

The electric transporter disclosed in the above-mentioned publication is designed to turn the body by the electric motors 4, 4 ', but is not suitable for small-scale direction correction. In other words, it is more efficient to make small-scale direction corrections by turning manually with the motors 4, 4 'stopped. However, the electric motor 4,
When the motor 4 'is stopped, the electric motors 4, 4' act as brakes and the front wheels 11, 11 'do not rotate.

[0005] Some large transport vehicles have a differential mechanism between the left and right wheels. Since the differential mechanism can absorb the rotation difference between the left and right wheels, it can be manually turned even when the electric motor or the engine is stopped.
However, the differential mechanism is expensive, and it is impossible to adopt it for a small and lightweight transport vehicle because it causes a rise in price.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transport vehicle that does not have a differential mechanism and that can easily be manually corrected in direction with an electric motor or an engine stopped.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is to attach a bub to a drive axle, attach a wheel to the hub, and interpose a wheel play mechanism between the hub and the drive axle. The left and right wheels with respect to the driving axle
A transport vehicle capable of idling in a range of less than 60 °, wherein the wheel play mechanism comprises: a protrusion protruding radially outward from a drive axle; and a circumferential groove provided on the hub to accommodate the protrusion. ,
And a stop member attached to the hub so as to protrude into the peripheral groove. The hub is rotatable with respect to the drive axle until the stop member hits the projection.

[0008] Since the wheels are able to spin at a predetermined angle, the wheels are spun to perform turning and direction correction. Therefore, the usability of the transport vehicle is dramatically improved.

According to a second aspect of the present invention, the projecting portion is a head portion of a headed pin detachably attached to a through hole formed in the drive axle, and the stop member is a bolt screwed into the hub. Features. Since the protruding portion is formed by the head portion of the headed pin and the stop member is formed by the bolt, the configuration becomes extremely simple, and the cost, size and weight of the wheel play mechanism can be easily reduced.

A third aspect of the present invention is characterized in that the diameter of the screw hole into which the bolt is screwed is made larger than the outer diameter of the head portion so that the headed pin can be inserted and removed through the screw hole. By removing the bolt, the headed pin can be easily inserted and removed through the screw hole.

According to a fourth aspect of the present invention, a through hole for inserting a tool for pushing the headed pin into the screw hole is formed in the cylindrical portion. A through hole is opened at a position facing the screw hole, a tool is inserted through the through hole, and the headed pin is pushed out. The headed pin can be easily removed through the screw hole.

A fifth aspect is characterized in that a blind plug is fitted in the through hole. By fitting a blind plug into the through hole, it is possible to prevent foreign matter such as dust from entering, and to seal grease in the circumferential groove.

According to the present invention, the projection is a pin driven into the drive axle, a head of a screw screwed into the drive axle, or a projection cut out from the drive axle, and the stop member is screwed into the hub. It is a bolt.

Since the projecting portion is a driving pin, a screw or a projecting portion, and the stop member is a bolt, the structure is extremely simple, and the cost, size and weight of the wheel play mechanism can be easily reduced. Can be. If the projecting portion is a driving pin, the pin has a simple structure, is inexpensive, and has a small number of driving steps, so that the cost of the wheel play mechanism can be further reduced. If the projection is the head of a screw-in screw, the screw can be attached to and detached from the drive axle.If multiple screw holes are provided in the drive axle, the screw mounting position can be changed, and the tread Adjustment becomes easy. If the protruding portion is formed as a protruding portion cut out from the drive axle, the number of machining steps is increased, but the number of parts can be reduced, and there is no fear of losing pins or screws, for example.
Parts management becomes easier.

According to a seventh aspect of the present invention, a bub is mounted on the drive axle, wheels are mounted on the hub, and a wheel play mechanism is interposed between the hub and the drive axle, so that the left and right wheels are rotated by 360 ° with respect to the drive axle. The wheel play mechanism comprises a cam groove provided on the drive axle within a range of less than 360 °, and a stop member attached to a hub so as to protrude from the cam groove. The hub is rotatable with respect to the drive axle until the stop member hits the end of the cam groove.

Since the wheels can idle at a predetermined angle, the wheels are idled to perform turning and direction correction. Therefore, the usability of the transport vehicle is dramatically improved. In addition, since the cam groove is provided on the drive axle, the inner diameter of the hub can be matched to the outer diameter of the drive axle, and the diameter of the bub can be easily reduced.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of the reference numerals. "Left" and "right" are directions viewed from the operator, "front" is the forward side, and "rear" is the opposite side. L is assigned to the left member and R is assigned to the right member. In the following description, an electric motor is used as a drive source, but the drive source may be a gasoline engine or a diesel engine.

In the following description, the correspondence between the claims and the drawings is as follows. Claim 1 is FIGS. 3 to 13, Claims 2 to 5 are FIGS. 3 to 10, Claim 6 is FIGS. 11 to 13,
Claim 7 corresponds to FIG.

FIG. 1 is a perspective view of a transport vehicle according to the present invention. The transport vehicle 1 includes left and right front wheels 2L and 2R and left and right rear wheels 3
L, 3R (3R not shown) is a four-wheeled vehicle having batteries 4L, 4R (the right battery 4R is not shown) between the front and rear wheels, and a frame frame at the front of a cargo bed 5 extending forward and backward. 6
Are fixed with bolts 7 (... indicates a plurality. The same applies hereinafter.), Fences 8, 8 are attached to the frame 6 and the rear surface of the loading platform 5, and the rear wheels 3, 3 are slanted rearward from the rear wheels 3, 3. Grip handle 9L upward,
Extend the 9R and put the brake lever 1 on the left handle 9L.
1. A shift lever 12 is attached to a right handle 9R.

FIG. 2 is an exploded perspective view of the lower structure of the carrier according to the present invention.
1, a motor mount base 22, an outer cylinder 23, and a gear case mount base 24 are integrally provided from top to bottom, battery support pieces 25 and 26 are provided at the center, and a torii-shaped rear frame 27 is provided at the rear. It is a thing. The rear frame 27 includes a pair of left and right vertical frames 29L and 29R that support the rear wheel axle 28 and a horizontal frame 31 that directly receives the carrier.

The rear wheel axle 28 is a non-rotating shaft. After the bases 32, 32 of the grip handles 9L, 9R are inserted, the rear wheels 3L, 3R can be attached with washers 33, 33 and bolts 34, 34. it can. The rear wheels 3L and 3R are free rotating wheels. The handles 9L, 9R are a kind of tilt handles that can be tilted about the rear wheel axle 28 as a center of rotation, and that fix pieces 35, 35 (one of which is not shown) on the way to a loading bed (not shown).

The holes 25a, 25 are formed in the battery support piece 25.
b, and holes 26a,
26b, one end of the battery cage 37 is inserted into the front holes 25a and 26a, and the battery cage 37 is inserted into the hole 2a.
5a and the hole 26a can be tilted about the fulcrum. Hole 25
A right battery cage (not shown) can be attached to b and the hole 26b.

Next, the front wheel drive system will be described. The carrier according to the present invention is characterized in that the front wheels 2L, 2R are driven by the electric motor 38 via the shaft direct drive system 40. Since no chains or belts are used, there is no starting shock and a large torque can be transmitted to the front wheels 2L and 2R, so that smooth and powerful running can be achieved. Direct drive system 40 for that purpose
A relay shaft 41 into which the output shaft 38a can be inserted;
Pinion bevel gear 4 attached to the lower end of this relay shaft 41
2, a large-diameter bevel gear 43 meshing with the pinion bevel gear 42, a front axle 44 as a drive axle spline-coupled to the large-diameter bevel gear 43, and wheel play mechanisms 50, 50.

FIG. 3 is an exploded perspective view of a wheel play mechanism (first embodiment) according to the present invention. The wheel play mechanism 50 includes through holes 52a, 52b, 52c formed through the front wheel axle 44 so as to be orthogonal to the axis 51 of the drive axle (the front wheel axle 44).
And a head pin 53 composed of a pin portion 53a and a head portion 53b inserted into these through holes 52a, 52b, 52c, a hub 60 that rotates integrally with the wheel, and a cylindrical portion 63 of the hub 60. And a bolt 66 to be screwed. Here, the head portion 53b is a specific example of a “projection portion” projecting radially outward from the drive axle, and a “stop member” attached to a hub so that the bolt 66 projects into a circumferential groove.
This is one specific example.

The hub 60 includes, for example, a flange 61, a pipe 62 welded to the flange 61, and a pipe 62
A cylindrical portion 63 having a larger diameter and coupled to the end of the pipe 62 in a state of being fitted thereon; a sufficiently large hole 64 formed in the cylindrical portion 63; and a nut 65 connected to the hole 64 and attached thereto.
, A bolt 66 screwed into the nut 65, a lock nut 67 for locking the bolt 66, a through hole 68 formed in the cylindrical portion 63 at a position facing the hole 64, and fitted into the through hole 68. And a blind plug 69 made of rubber or resin.

71 is a washer, 72 is a C-shaped retaining ring, 73 is a retaining ring groove, 74 and 74 are bolts, 75 and 75 are nuts, 7
6 is a wheel. Reference numeral 65a denotes a screw hole, together with the hole 64, the head 5 of the headed pin 53.
It is characterized in that the diameter is larger than the outer diameter of 3b.

FIG. 4 is an assembly sectional view of the wheel play mechanism (first embodiment) according to the present invention, and is an assembly view of FIG. 3 (exploded view).
By fixing the flange 61 at 5,75, the hub 6 is attached to the front wheel.
0 indicates that the wheel is mounted on the front wheel axle 44 by inserting one end of the front wheel axle 44 into the hub 60.
Note that the relationship between the pin 53 with the head and the cylindrical portion 63, the nut 65, and the bolt 66 is difficult to understand.

FIG. 5 is an enlarged view of a main part of FIG. 4. A washer 71 is placed on the headed pin 53 side, and a C-shaped retaining ring 72 is set in a retaining ring groove 73 to prevent the washer 71 from coming off. That is, when the pipe 62 and the cylindrical portion 63 move toward the front wheel axle 44, the edge (left end face) of the pipe 62 hits the head portion 53b when it moves to the left in the figure, and the pipe 62 and the cylindrical portion 63 move toward the right in the figure Since the washer 71 hits the head portion 53b, there is no fear that the hub will come off from the front wheel axle 44.

A portion surrounded by the edge of the pipe 62, the inner surface of the cylindrical portion 63, and the washer 71 is a peripheral groove 78. By filling the peripheral groove 78 with grease (not shown), Wear can be prevented, and the washer 71 can be attached to the C-shaped retaining ring 72. As a result, the cylindrical portion 63 and the pipe 62
Is moved laterally along the front wheel axle 44, there is no concern that the washer 71 will come off undesirably.

FIG. 6 is a sectional view taken along the line 6-6 in FIG. 4 (the blind plug 69 is kept removed for convenience). The cylindrical portion 63 surrounds the front wheel axle 44 through the circumferential groove 78, and the bolt 66 This indicates that the tip protrudes into the circumferential groove 78. That is, the bolt 66 is screwed into the nut 65 in a state where the lock nut 67 is loosened. When the tip of the bolt 66 comes into contact with the front wheel axle 44, the bolt 66 is slightly returned. On the other hand, the bolt 66 can be set with a little gap.

The operation of the wheel play mechanism and the carrier having the above-described structure will be described below. FIGS. 7A to 7D are operation explanatory diagrams of the wheel play mechanism (first embodiment) according to the present invention. In (a), a front wheel axle 44 which is a drive axle is
It is assumed that the vehicle has been driven as shown by the arrow to move forward. Front wheel 2R
Is stopped, and only the front wheel axle 44 turns. In (b), from the time when the head portion 53b of the headed pin 53 hits the bolt 66, the front wheel 2R also starts to rotate together with the front wheel axle 44 as shown by the arrow. The truck is now moving forward.

(C) shows a state in which the vehicle has shifted from moving forward to stopping. In this state, the bolt 66 is attached to the head 53b.
, The rotation of the front wheel 2R is possible under the following conditions. In (d), with the front wheel axle 44 stationary, the front wheel 2R can be rotated as shown by the arrow.
That is, the front wheel 2R can rotate in the counterclockwise direction in the drawing within the range of the angle θ (about 300 °) until the bolt 66 hits the head 53b next time. By this operation, it becomes possible to correct the turn and direction of the transport vehicle as described below.

FIG. 8 is an explanatory view of a turn of the transport vehicle according to the present invention. The transport vehicle 1 needs to make a 180 ° turn at a headland (edge of cultivated land) for turning. At this time, the electric motor is stopped, and, for example, turns counterclockwise around the left front wheel 2L as shown in the figure. Since the axle is stationary, only the right front wheel 2R idles as needed. Since the front wheel tread is T1, the turning radius is also equal to T1,
The traveling distance of the right front wheel 2R is π · T1. The outer diameter of the front wheel is D1, and the rotation speed of the front wheel is n. π · D1
Since n = π · T1, n = T1 / D1. Assuming that the tread T1 = 190 mm and the front wheel outer diameter D1 = 360
mm, n = 190/360 = 0.53 rotation = 1
It is equivalent to 90 °. Since this angle 190 ° is smaller than the idle rotation angle 300 °, it is possible to make a sufficient 180 ° turn. Since the direction correction is a small-scale turn, the direction correction can be easily performed similarly to the above-mentioned turn.

FIGS. 9 (a) to 9 (c) are views for explaining how to attach and detach the headed pin according to the present invention. In (a), in order to remove the headed pin 53, first, the lock nut 67 is loosened, and the bolt 66 is removed from the nut 65. At the same time, the blind plug 69 is removed. In (b), a through hole 6 for a tool 79 such as a thin round bar is used.
8 and push out the pin 53 with the head. The headed pin 53 can now be easily removed through the hole 64 and the nut 65. In (c), for example, the through holes 52a, 52
The hubs 60, 60 indicated by the imaginary lines fitted in a are moved to the other through holes 52c, 52c, the pins with heads 53, 53 are dropped, and the bolts 66, 66 are set. Can be easily adjusted.

FIG. 10 is a view showing a second embodiment of the wheel idle mechanism according to the present invention.
The cylindrical portion 63 is formed integrally with the cylindrical portion 63, and the circumferential groove 78
Is formed by boring. The other parts are the same as those in FIG. 4, and the description is omitted by using the reference numerals.
However, as compared with FIG. 4, the washer 71 and the C-shaped retaining ring 72 of FIG. 4 are unnecessary, so there is no need to worry about losing these parts, welding of the flange 61 and the pipe 62, Since welding with the cylindrical portion 63 is not required, the number of processing steps can be reduced, and it can be said that the configuration is particularly suitable for mass production.

In the figure, reference numeral 81 denotes grease. By filling the grease 81 in the circumferential groove 78, the contact between the headed pin 53 and the bolt 66 is smoothed, and the life of each component is extended. be able to. Further, by making the cylindrical portion 63 thicker, it is possible to directly cut a screw (screw hole 65a) into the hole 64, so that the nut 65 is not always necessary.

FIGS. 11 (a) and 11 (b) are diagrams showing a third embodiment of a wheel play mechanism.
As shown in (1), a pin hole 83 is formed in the front wheel axle 44, and a pin 84 having a head 84a is driven into the pin hole 83.
(B) is an assembling cross-sectional view, in which a nut 85 is welded to the cylindrical portion 63 on the hub side, and a bolt 86 is screwed into the nut 85 to insert the tip of the bolt 86 into the circumferential groove 78. Show. 87 is a lock nut.

Here, the nuts 85 and the bolts 86 have diameters much smaller than the nuts 65 and the bolts 66 in FIG. Although the pin 84 cannot be removed via the nut 85, the wheel play mechanism 50 can be made more compact.

If the cylindrical portion 63 and the bolt 86 are stationary, the front wheel axle 44 can rotate about 300 ° until the head 84a hits the bolt 86. Similarly, when the front wheel axle 44 is stationary, the cylindrical portion 63 can be turned by about 300 °. Therefore, even if the front wheel axle 44 is stopped, the front wheels can idle.

That is, in the third embodiment, the "projecting portion" is constituted by a pin, and the "stop member" is constituted by a bolt. If the protruding portion is a pin, the pin has a simple structure, is inexpensive, and has a small number of driving steps, so that the cost of the wheel play mechanism can be further reduced.

FIG. 12 is a view showing a fourth embodiment of a wheel play mechanism. In this wheel play mechanism 50, a convex portion 89 is cut out when the front wheel axle 44 is cut, and other structures and operations are performed. Are the same as those in FIG. 11B, and the description is omitted by using the reference numerals. In the fourth embodiment, the "projection" is a projection cut out from the drive axle. Although the number of machining steps is increased, the number of parts can be reduced, and there is no fear of losing pins or screws, for example. , Parts management becomes easy.

FIGS. 13A to 13C are diagrams showing a fifth embodiment of the wheel play mechanism. In this wheel play mechanism 50, FIG.
As shown in the figure, a screw hole 91a is provided in the front wheel axle 44,
A screw 92 having a head 92a is screwed into the screw hole 91a. If a plurality of screw holes 91a, 91b, 91c are provided in the front wheel axle 44 as shown in FIG.
Can be repositioned as indicated by the arrow. (C) is an assembly sectional view, in which a nut 85 is welded to the cylindrical portion 63 on the hub side and a bolt 86 is screwed into the nut 85,
This indicates that the tip of the bolt 86 has been inserted into the circumferential groove 78. The operation is the same as that of FIG.

That is, in the fifth embodiment, the "projecting portion" is formed as the head 92a of the screw 92. The screw 92 is detachable from the drive axle, and a plurality of screw holes 91a, If 91b and 91c are provided, the screw 9
2 can be changed, and the tread can be easily adjusted.

FIGS. 14A to 14C are views of a sixth embodiment of the wheel play mechanism. In (a), the front wheel axle 44 has 3
The cam groove 94a is cut within a range of less than 60 °. Similarly, the cam grooves 94b and 94c are cut elsewhere. As shown in (b), the hub 60 is attached to the front wheel axle 44, and the tip of the bolt 86 as a stop member faces the cam groove 94a. As is clear from the figure, the hub 60 is connected to the other cam grooves 9.
4b or 94c can also be attached, allowing tread adjustment.

(C) is a sectional view taken along line CC of (b),
Since the cam groove 94a is a groove of less than 360 °, it has two end portions 94d and 94e. Then, when the cylindrical portion 63 is turned with respect to the stationary front wheel axle 44, the end portion 94d
Or, the cylindrical portion 63 rotates right or left until the bolt 86 hits the 94e.

Since the wheels are able to spin at a predetermined angle, the wheels are spun to perform turning and direction correction. Therefore, the usability of the transport vehicle is dramatically improved. In addition, FIG.
It can be seen that the diameter of the cylindrical portion 63 is slightly smaller than that of FIG. That is, in the sixth embodiment, the cam grooves 94a to 94a
Since 94c is engraved on the front wheel axle 44, the hub, that is, the inner diameter of the cylindrical portion 63 can be matched to the outer diameter of the front wheel axle 44, and the diameter of the bub can be easily reduced.

In the first aspect, the circumferential groove provided in the hub is
The configuration is arbitrary as long as there is a space for accommodating the protruding portion and the tip of the stopper member. Further, the pin for driving in claim 6 may be a simple cylindrical pin, and the screw may be one obtained by cutting a male screw into a round bar. I just need. Therefore, the shapes of the pins, screws, and protrusions are not limited to the examples.

The transport vehicle according to the present invention is not limited to a transport vehicle in a narrow sense, but may be an agricultural work vehicle, a forestry work vehicle, a fishery work vehicle, a work vehicle of other general industries, various trucks, and various types of trucks. , Various electric vehicles, and gasoline vehicles.

[0049]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, even when the driving axle is stopped due to a driving system such as an electric motor, the wheels can be idled at a predetermined angle, and the turning and direction correction of the transport vehicle can be performed by the idle rotation of the wheels. . Therefore, the usability of the transport vehicle is dramatically improved.

According to a second aspect of the present invention, the protrusion is a head portion of a headed pin detachably attached to a through hole formed in the drive axle, and the stop member is a bolt screwed into the hub. Features a protruding part with a head with a head,
Since the stop member is formed by bolts, the structure is extremely simple, and the cost, size, and weight of the wheel play mechanism can be easily reduced.

According to a third aspect of the present invention, the diameter of the screw hole into which the bolt is screwed is made larger than the outer diameter of the head portion, so that the headed pin can be inserted and removed through the screw hole. By removing the bolt, the headed pin can be easily inserted and removed through the screw hole.

According to the fourth aspect, a through hole is formed at a position facing the screw hole, a tool is inserted through the through hole, and a pin with a head is extruded. The headed pin can be easily removed through the screw hole.

According to a fifth aspect of the present invention, a blind plug is fitted into the through hole,
It is possible to prevent foreign substances such as dust from entering, and to seal grease in the circumferential groove.

In claim 6, the projecting portion is a driving pin, a screw or a convex portion, and the stop member is a bolt.
The configuration is extremely simple, and the cost, size, and weight of the wheel play mechanism can be easily reduced. If the projecting portion is a driving pin, the driving pin has a simple structure, is inexpensive, and has a small number of driving steps, so that the cost of the wheel play mechanism can be further reduced. If the projection is the head of a screw-in screw, the screw can be attached to and detached from the drive axle.If multiple screw holes are provided in the drive axle, the screw mounting position can be changed, and the tread Adjustment becomes easy. If the protruding portion is formed as a protruding portion cut out from the drive axle, although the number of machining steps is increased, the number of components can be reduced, and there is no fear of losing pins or screws, for example, and component management becomes easy.

According to the seventh aspect, even when the drive axle is stopped due to a drive system such as an electric motor, the wheels can be rotated by a predetermined angle, and the rotation and the direction of the transport vehicle can be corrected by the idle rotation of the wheels. be able to. Therefore, the usability of the transport vehicle is dramatically improved. In addition, since the cam groove is provided on the drive axle, the inner diameter of the hub can be matched to the outer diameter of the drive axle, and the diameter of the bub can be easily reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a transport vehicle according to the present invention.

FIG. 2 is an exploded perspective view of a lower structure of the transport vehicle according to the present invention.

FIG. 3 is an exploded perspective view of a wheel play mechanism (first embodiment) according to the present invention.

FIG. 4 is an assembled sectional view of a wheel play mechanism (first embodiment) according to the present invention.

FIG. 5 is an enlarged view of a main part of FIG. 4;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 4;

FIG. 7 is an operation explanatory view of a wheel play mechanism (first embodiment) according to the present invention.

FIG. 8 is an explanatory view of a turn of the transport vehicle according to the present invention.

FIG. 9 is an explanatory view of the attaching / detaching procedure of the headed pin according to the present invention.

FIG. 10 is a view of a second embodiment of the wheel play mechanism of the present invention.

FIG. 11 is a diagram showing a third embodiment of the wheel play mechanism of the present invention.

FIG. 12 is a view of a fourth embodiment of the wheel play mechanism of the present invention.

FIG. 13 is a view showing a fifth embodiment of the wheel play mechanism of the present invention.

FIG. 14 is a view showing a sixth embodiment of the wheel play mechanism of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Truck, 2L, 2R ... Front wheel as a drive wheel, 44 ...
Front wheel axle as drive axle, 50 ... wheel play mechanism, 51
... Axle axis, 52a-52c ... Through hole, 53 ... Headed pin, 53a ... Pin portion, 53b ... Protrusion (head portion)
Reference numeral 60: hub, 63: cylindrical portion, 65a: screw hole, 66, 8
6 stop member (bolt), 68 through hole, 69 blind plug, 78 peripheral groove, 79 tool, 84a projection (pin head), 89 projection (convex), 92a projection (Screw head), 94a to 94c: cam groove, 94c, 94d: end portion of cam groove, θ: angle at which idle rotation is possible.

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[Procedure amendment]

[Submission date] January 28, 1999 (1999.1.2
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art With the spread of plastic greenhouses, melon cultivation has been actively performed even in cold regions.
Large greenhouse is 50m to allow for great harvest
It is as long as ｍ100 m, and mechanical power is required to move fertilizers, seedlings and crops. Conventionally, a tractor, had been using a cultivator, the tractor and cultivator, is not good maneuverability in the not narrow house.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) B62B 3/00 EF term (reference) 3D035 BA02 3D050 AA01 AA12 BB03 DD03 EE08 EE15 KK03 KK14 3D052 AA05 AA18 BB08 DD01 DD03 DD06 EE02 FF03 GG00 HH01 JJ32

Claims (7)

[Claims] 1. A hub is mounted on a drive axle, a wheel is mounted on the hub, and a wheel play mechanism is interposed between the hub and the drive axle so that the left and right wheels can be mounted on the drive axle.
A transport vehicle capable of idling within a range of less than 60 °, wherein the wheel play mechanism includes a protrusion protruding radially outward from a drive axle, and a circumferential groove provided in the hub to accommodate the protrusion. And a stop member attached to the hub so as to protrude into the circumferential groove, wherein the hub is rotatable with respect to the drive axle until the stop member hits the protrusion. 2. The method according to claim 1, wherein the protrusion is a head portion of a headed pin detachably attached to a through hole formed in a drive axle, and the stop member is a bolt screwed into a hub. The carrier according to claim 1, wherein: 3. The head-mounted pin can be inserted and removed through a screw hole by making a diameter of a screw hole into which the bolt is screwed larger than an outer diameter of the head portion. 2. The transport vehicle according to 2. 4. The transport vehicle according to claim 3, wherein a through hole for inserting a tool for pushing a headed pin into the screw hole is formed in the cylindrical portion. 5. The transport vehicle according to claim 4, wherein a blind plug is fitted in said through hole. 6. The projection is a pin driven into a drive axle, a screw head screwed into the drive axle, or a protrusion cut out from the drive axle, and the stop member is a bolt screwed into a hub side. The carrier according to claim 1, wherein: 7. A hub is mounted on the drive axle, a wheel is mounted on the hub, and a wheel play mechanism is interposed between the hub and the drive axle, so that the left and right wheels can be connected to the drive axle.
Claims 1. A transport vehicle capable of idling in a range of less than 60 °, wherein the wheel play mechanism comprises a cam groove provided in a drive axle in a range of less than 360 °, and a stop member attached to a hub so as to protrude into the cam groove. And a hub capable of rotating with respect to the drive axle until the stop member hits the end of the cam groove.