JPH0618173U - Tow truck - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a tow truck equipped with a braking device that reliably and automatically operates when traveling is stopped. [Structure] The base end portion of the tractor 6 is connected to the front portion of the vehicle body 11 so as to be able to move forward and backward with a constant stroke, and the braking rod 8 is movable in the axial direction by the same amount as the movement stroke of the tractor 6. When installed, the braking rod 8 is constantly subjected to the action of the spring 14, and the braking rod 8 is linked to the tractor 6 and is constantly pushed to the forward limit position. Braking piece 10 for rear wheel 5
Is installed so that it can be brought into and out of contact with the rear wheel 5, the braking operation member 9 is installed at the rear portion of the vehicle body 11, and the braking operation member 9 and the braking rod 8 are connected in series. [Effect] When the driving vehicle stops during towing, a braking force is automatically applied to the rear wheels 5 of the towing vehicle 1 immediately, causing a rear-end collision with a vehicle (driving vehicle, towing vehicle) in front of the vehicle or sliding to the left or right with excessive force. The danger that the line will be disturbed due to meandering movement is prevented in advance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a towing vehicle that is towed by being connected to a drive vehicle and by connecting several vehicles to each other, and more specifically, is provided with a braking device that operates reliably and automatically when traveling is stopped. Regarding tow truck.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, as a braking device for a hand truck, a type in which a foot pedal is operated is disclosed in, for example, Japanese Utility Model Publication No. 1-36685 and Japanese Utility Model Publication No. 38-1823. Japanese Patent Publication No. 47001 discloses a type in which a manual operation lever is used, which are publicly known and put into practical use.

However, a tow truck equipped with a braking device has not been put into practical use and is not known.

[0004]

[Problems to be solved by the present invention]

 Conventional towing trucks do not have a braking device that works when the vehicle is stopped, and try to brake everything with the braking force of the driving vehicle. However, when a heavy load is loaded, the inertial force during running exceeds the braking force of the driving vehicle, and when the vehicle is stopped, the braking system of the driving vehicle is fully used and the vehicle collides from behind. There was a high risk that the drive vehicle would be pushed out by the tow truck and the drive vehicle would overrun beyond the planned stop position and cause an accident. In addition, if one or several empty towing trucks are connected, when the vehicle stops due to the braking force of the driving vehicle, subsequent towing trucks will collide with the trucks in front one after another and noisy metal. There is a risk of hitting people and things in the surroundings by making a shocking sound of noise and making noise around the surroundings, and the dolly with excessive force slides in a twisting direction to the left and right and becomes a meandering state. Further, there is a problem that the connector portion is particularly easily damaged by the repeated impact action as described above, which is a problem to be solved.

[0005]

[Means for Solving the Problems] As means for solving the above-mentioned problems of the prior art, a tow truck according to the present invention has a front wheel 4 which is a free wheel and a rear wheel which is a fixed wheel under a vehicle body 11. 5, a tractor 6 connected to a front vehicle is provided at a substantially central portion of a vehicle front portion, and a connector 15 is provided at a substantially central portion of a vehicle body rear portion for connecting a tractor of a succeeding vehicle, It features the following configuration. (A) The base end portion of the tractor 6 is connected to the front portion of the vehicle body 11 so as to be able to move forward and backward with a constant stroke in the front-rear direction in the traveling direction. (B) On the front part of the vehicle body 11, the braking rod 8 is arranged substantially parallel to the forward / backward movement direction of the tractor 6 and is movable in the axial direction at least as much as the movement stroke of the tractor 6. Has been done. (C) The braking rod 8 constantly receives an acting force in a direction for releasing the braking action of the braking piece described later by the spring 14 or the like, and the braking rod 8 is linked with the tractor 6 and pulled by the acting force. The base end of the container 6 is constantly pushed to the forward limit position. (D) The braking piece 10 for braking the rear wheel 5 is installed so as to be able to come into contact with and separate from the rear wheel 5. (E) A braking operation member 9 for bringing the braking piece 10 into pressure contact with the rear wheel 5 is installed in the rear portion of the vehicle body 11, and the braking operation member 9 and the braking rod 8 are connected in a series operating relationship. (See FIGS. 1 to 3).

In the above-described tow truck, two rear wheels 5 are installed below the vehicle body 11 in a symmetrical arrangement, and a braking piece 10 for braking the rear wheel 5 and each braking piece are pressed against the rear wheel 5. A total of two braking operation members 9 are installed, one for each rear wheel, and the two braking operation members 9 and 9 and the braking rod 8 at the front of the vehicle body have a planar shape which corresponds to the position of the braking rod. It is also characterized in that they are connected in a series of operating relations by a frame body 18 having a substantially isosceles triangle shape with the apex as a vertex (see FIG. 1).

The towing vehicle according to the second invention is also provided with a front wheel 4 which is a free wheel and a rear wheel 5 which is a fixed wheel under the vehicle body 11, and a front vehicle is provided at a substantially central portion of a front portion of the vehicle body. A tractor 6 to be connected is provided, and a connector 15 for connecting a tractor of a succeeding vehicle is provided at a substantially central portion of a rear portion of the vehicle body, and is characterized by the following configuration. (A) The base end portion of the tractor 6 is connected to the front portion of the vehicle body so as to be able to move forward and backward in the traveling direction at a constant stroke. (B) On the front part of the vehicle body 11, the braking rod 8 is arranged substantially parallel to the forward / backward movement direction of the tractor 6 and is movable in the axial direction at least as much as the movement stroke of the tractor 6. Has been done. (C) The braking rod 8 constantly receives an acting force in a direction for releasing the braking action of the braking piece described later by the spring 14 or the like, and the braking rod 8 is linked with the tractor 6 and pulled by the acting force. The base end of the container 6 is constantly pushed to the forward limit position. (D) The braking piece 10 for braking the rear wheel 5 is installed so as to be able to come into contact with and separate from the rear wheel 5. (E) A displacement detection mechanism A for detecting the displacement of the braking rod 8 or the tractor 6 in the backward direction is installed. (F) A braking operation mechanism B for bringing the braking piece 10 into pressure contact with the rear wheel 5 is installed. The braking operation mechanism B is connected to the displacement detection mechanism A, and according to the displacement detected by the displacement detection mechanism A 1. The braking operation mechanism B is driven to bring the braking piece 10 into pressure contact with the rear wheel 5 (see FIGS. 4 to 10).

In the above-mentioned tow truck, the displacement detection mechanism A and the braking operation mechanism B are connected by a sheathed cable 23 so as to transmit mechanical displacement and force (see FIGS. 4 and 5), The displacement detection mechanism A is configured to detect the displacement of the braking rod 8 as a hydraulic pressure or an electric quantity, and the braking operation mechanism B is a hydraulic or electric drive unit that operates based on the hydraulic pressure or the electric quantity. It is also characterized by being configured as a mechanism having.

[0009]

[Action]

 The braking rod 8 is constantly pushed by the acting force of the spring 14 in the direction in which the braking action of the braking piece 10 is released (forward in the traveling direction). Therefore, the braking operation member 9 connected to the braking rod 8 in a series of operating relationship also escapes in the direction in which the braking action is always released. Therefore, the rear wheel 5 freely rotates without being braked by the braking piece 10, and travels freely, for example, following the drive vehicle connected by the tractor 6. However, when the driving vehicle stops by operating its braking device and the motion inertial force of the towing truck 1 which follows from behind exceeds the acting force of the spring 14 acting on the braking rod 8, the vehicle body 11 of the towing truck 1 is Moves forward by the stroke allowed at the base end of the tractor 6 and approaches the drive vehicle. That is, relative movement of the stroke occurs between the base end of the tractor 6 and the vehicle body 11, and the braking rod 8 linked to the tractor 6 moves backwards the braking rod 8 by the relative amount. Let The backward movement of the braking rod 8 is immediately transmitted as an operation of the braking operation member 9 that is in a series of operations, and the braking operation member 9 presses the braking piece 10 against the rear wheel 5 to generate a large braking force on the rear wheel 5. Let Therefore, the rotation of the rear wheel 5 is stopped and the tow truck 1 is stopped.

Even in the case of the configuration of the displacement detection mechanism A and the braking operation mechanism B (embodiments of FIGS. 4 to 10), the operation principle of braking and stopping the towing vehicle 1 is exactly the same. The braking state of the rear wheel 5 is maintained as it is, unless the stop positions of the drive vehicle, the towing vehicle 1 and the tow vehicles moving forward and backward are changed. Next, when the stopped drive vehicle starts traveling, first, the tractor 6 moves forward together with the drive vehicle. Therefore, when the base end of the drive vehicle is advanced by a certain stroke, the vehicle body 11 of the tow truck 1 is pulled. Tow. At this time, as the base end portion of the tractor 6 advances, the braking rod 8 also gradually moves forward due to the acting force of the spring 14, and the braking operation member 9 or 25 brakes before the towing vehicle 1 starts running. The piece 10 is moved away from the rear wheel 5, and the braking action is released. Therefore, there is no problem in starting the running of the towing vehicle 1.

[0011]

【Example】

 Next, the illustrated embodiment of the present invention will be described. The tow truck 1 shown in FIGS. 1 to 4 has two front wheels 4 and 4 which are free wheels (own casters) and two rear wheels 5 which are fixed wheels under a vehicle body 11 having a rectangular plane. , 5, and a drafter 6 connected to a front vehicle (driving vehicle or towing trolley) at a substantially central portion of a front portion of the vehicle body, and a tractor 6 of a trailing trolley at a substantially central portion of a rear portion of the vehicle body. It has a connector 15 for connecting. The rear wheel 5 is not limited to a fixed wheel, but may be a wheel provided with a switching device between a free state and a fixed state as disclosed in, for example, Japanese Utility Model Publication No. 63-38133.

As shown in FIGS. 2 and 3, a U-shaped connecting frame 7 is provided at a substantially central position on the front part of the vehicle body when viewed from the front, and both side parts of the connecting frame 7 are provided as shown in FIG. When viewed from the front, an L-shaped guide groove 12 is formed symmetrically. A shaft 13 that is slidable along the guide groove 12 is provided so that a base end portion of the tractor 6 can be moved forward and backward with a certain stroke in the front-back direction of the traveling direction of the towing vehicle 1. The length of the horizontal portion 12a of the L-shaped guide groove 12 corresponds to the stroke of the forward / backward movement of the base end portion of the tractor 6. The vertical portion 12b is used when the tractor 6 when not in use is vertically placed and stored as shown by a two-dot chain line in FIG. The base end portion of the tractor 6 which is erected vertically is inserted into the slit 7a provided in the bottom surface portion of the connecting frame 7.

A braking rod 8 supported by a slide bearing 16 at a position directly below the connecting frame 7 on the lower surface of the front part of the vehicle body 11 is arranged substantially parallel to the moving direction of the tractor 6, and It is installed so as to be movable in the axial direction at least as much as the moving stroke of the tractor 6. A direction in which the braking action of a damping piece described later is released between the braking rod 8 and a hemispherical portion 8a formed at a front portion of the sliding bearing 16 and having a slightly larger diameter at the front end of the braking rod 8. A compression type coil spring 14 that constantly exerts an acting force on is wound. The hemispherical portion 8a at the front end of the braking rod 8 is brought into contact with the pressure receiving plate 17 provided vertically downward on the lower surface of the tractor 6 so that the two are linked. The shaft 13 is always pushed to the forward limit position of the guide groove 12 (the right end of the horizontal portion 12a in FIG. 3). As long as the above function is achieved, the means for linking the tractor 6 and the braking rod 8 is not limited to the method using the pressure receiving plate 17, and may be implemented in other ways.

A braking piece 10 made of a springy flat plate material having excellent elasticity (flexibility) is installed directly above the rear wheel 5 so as to be able to come into contact with and separate from the outer peripheral surface of the rear wheel 5. Has been done. The braking piece 10 has a base end portion 10a fixed to the vehicle body 11 side, and a head portion 10b formed in a flat ring shape that is easy to press. The braking piece 10 is normally separated from the rear wheel 5 due to its spring property, but is pressed against the outer peripheral surface of the rear wheel 5 by pushing down the head portion 10b to generate a braking force.

The braking operation member 9 that pushes down the head portion 10b of the braking piece 10 and presses it against the rear wheel 5 is formed as a rod-shaped member having a downwardly sloping inclined surface 9a at the rear end portion thereof. A slide bearing 16 provided on the lower surface of the shaft is supported so that it can slide in the axial direction freely. When viewed two-dimensionally as shown in FIG. 1, two rear wheels 5 and 5 are installed symmetrically below the vehicle body, and a braking piece 10 and a braking operation member 9 for braking each rear wheel. Is installed on one rear wheel 5 each, and the two left and right braking operation members 9 and 9 and the braking rod 8 at the front of the vehicle body have a top shape with the position of the braking rod 8 at the top due to the steel pipe and joint. A frame body 18 having a high rigidity assembled into a substantially isosceles triangle is connected in a series of moving (moving) relationships. Both ends of the horizontal member 18a corresponding to the base of the triangle are connected to the two left and right braking operation members 9 and 9 at a right angle by joints 18b. The heads of the two diagonal members 18c corresponding to the oblique sides are connected to the rear end of the braking rod 8 by a joint 18d.

When the towing vehicle 1 is towed by connecting the tow vehicle 6 to the drive vehicle, the shaft 13 at the base end of the tow vehicle 6 hits the front end of the guide groove 12 to transmit the tow force. At this time, the braking rod 8 is also pushed by the coil panel 14 and follows the pressure receiving plate 17 that has moved forward together with the tractor 6 and moves forward. Therefore, the braking operation member 9 linked to the braking rod 8 is also moved forward through the frame 18, and the inclined surface 9a of the braking operation member 9 is slightly touched by the head 10b of the braking piece 10. Or it will be a little distant relationship. Therefore, the braking piece 10 is slightly separated from the outer peripheral surface of the rear wheel 5, and the rear wheel 5 is in an uncontrolled state in which it freely rotates. When the drive vehicle stops by operating the braking device, the tractor 6 and the shaft 13 at its base end also stop together with the drive vehicle, while the towing vehicle 1 still advances due to the motion inertia. The forward movement of the towing vehicle 1 at this time is allowed until the shaft 13 hits the rear end of the horizontal portion 12a of the guide groove 12. Thus, a relative movement of the stroke defined as the length of the horizontal portion 12a of the guide groove 12 occurs between the tractor 6 and the vehicle body 11. By the relative movement indicated by the chain double-dashed line in FIG. 3, the pressure receiving plate 17 of the tractor 6 moves the braking rod 8 rearward. The rearward movement of the braking rod 8 causes the braking operation member 9 to sequentially move rearward through the frame body 18, so that the inclined surface 9a pushes down the damping piece 10 to press it against the outer peripheral surface of the rear wheel 5 and to generate a large braking force. Is generated and the rotation of the rear wheel 5 is stopped, so that the tow truck 1 is stopped. The braking and stopping of the tow truck 1 is performed at a midway position while the shaft 13 at the base end of the tractor 6 moves from the front end to the rear end of the horizontal portion 12a of the guide groove 12, at least the shaft 13 being at the horizontal portion 12a. It is designed and manufactured with care so that a so-called rear impact force (impact force) that hits the rear end is not transmitted to the driving vehicle. The tow truck 1 that has once stopped as described above self-maintains the stopped state due to braking by designing the acting force of the coil spring 14 to be smaller than the static inertia force or the rolling resistance of the wheels 4 and 5. .. Of course, when the towing by the driving vehicle or the like is started, the towing vehicle 1 immediately returns to the braking release state and travels without trouble as described above.

If the front wheels 4 are conventionally known wheels with a brake device, the tow truck 1 is applied with a brake when it is transported by truck, etc., preventing inadvertent movement to prevent damage, etc. Can be transported.

[0018]

Second Embodiment The braking device shown in FIGS. 4 to 7 is also applied to the towing vehicle 1 shown in the first embodiment, and the braking rod 8 is provided on the front portion of the vehicle body 11. A displacement detection mechanism A is installed to detect the movement in the backward direction as the displacement. Further, at a position near each rear wheel 5 on the rear part of the vehicle body, a braking operation mechanism B that is driven based on the displacement of the braking rod 8 detected by the displacement detection mechanism A to bring the braking piece 10 into pressure contact with the rear wheel 5. Are installed, and the displacement detection mechanism A and the braking operation mechanism B are connected by a cable with a sheath 23 that transmits mechanical displacement and force.

In the displacement detecting mechanism A, as shown in FIG. 5, a substantially intermediate portion of the rotary arm 20 is rotatably supported by a shaft 21 on one end of an L-shaped bracket 40 fixed to the frame 11a of the vehicle body 11, A roller 19 provided at one end of the rotating arm 20 is in contact with a tapered portion 8b formed in a taper shape at a rear end portion of the braking rod 8. A cable end 22 of a sheathed cable 23 is tangentially connected to the rotary arm 20 at the other end of the rotary arm 20. The end of the sheath 23a is fixed to the other end of the L-shaped bracket 40 with a double nut 41. Therefore, when the braking rod 8 moves backward and backward, the rotary arm 20 rotates about the axis 21 as shown by the chain double-dashed line in FIG. 4 according to the displacement of the taper portion 8b at the rear end, and the length of the chord at this time. The cable with sheath 23 is pulled and moved by a considerable amount.

As shown in FIGS. 5 and 6, the braking operation mechanism B is mounted by fixing the bearing 24 downward to the top plate 42a of the bracket 42 of the rear wheel 5 fixed to the lower surface of the rear part of the vehicle body 11. Has been. A braking operation member 25 is installed at a position relatively lower than the bearing 24 so as to be rotatable about a shaft 27, and one end of the braking operation member 25 is rotated in the clockwise direction in the figure to rotate the head of the braking piece 10. It is configured to push down on 10b. The cable end 26 of the sheathed cable 23 is connected to the other end of the braking operation member 25. As shown in FIG. 5, the end portion of the sheath 23a is fixed to one surface of a spring receiving plate 43 fixed to the frame 11b of the vehicle body 11 with a nut 44. A compression type coil spring 28 is wound around the outer circumference of the cable between the spring receiving plate 43 and the cable end 26 to constantly push the braking operation member 25 to the non-braking position shown in FIG. Therefore, when the cable 23 is pulled and moved according to the rotation of the rotary arm 20 of the displacement detection mechanism A that detects the backward movement of the braking rod 8, the braking operation member 25 of the braking operation mechanism B causes the coil spring 28 to move. While being compressed and rotated about the shaft 27, the free end of the braking operation member 25 abuts against the head 10b of the braking piece 10 and pushes it down, and presses against the outer peripheral surface of the rear wheel 5 to generate a large braking force. Let However, when the braking rod 8 is moved forward by the coil spring 14 and the force pulling the cable 23 is released, the coil spring 28 of the braking operation mechanism B pushes back the cable end 26 and reverses the braking operation member 25 to perform braking. Restore to the unlocked position. Since the cable 23 is inevitably pulled and moved, the rotary arm 20 of the displacement detecting mechanism A is restored to the neutral position shown by the solid line in FIG.

[0021]

[Third Embodiment] The braking device shown in FIGS. 8 to 10 is also applied to the towing vehicle 1 shown in the first embodiment, and, like the second embodiment, the front of the vehicle body. A displacement detection mechanism A for detecting the movement of the braking rod 8 in the backward direction as a displacement is installed in the section. Further, at a position near each rear wheel 5 on the rear part of the vehicle body, a braking operation mechanism is driven based on the displacement of the control rod 8 detected by the displacement detecting mechanism A to bring the braking piece 10 into pressure contact with the rear wheel 5. B is installed. In the illustrated embodiment, both the displacement detection mechanism A and the braking operation mechanism B are hydraulic mechanisms, and the displacement detection mechanism A and the braking operation mechanism B are connected by two hydraulic hoses 45 and 45 '.

In the displacement detection mechanism A, the rod 33 a of the piston 33 built in the hydraulic cylinder 30 fixed to the vehicle body 11 is arranged substantially at right angles to the axis of the braking rod 8, and the rear end of the braking rod 8 is arranged. The roller 19 attached to the tip of the piston rod 33a comes into contact with the tapered portion 8b formed in the above. A compression coil spring 32 for restoring operation is installed behind the piston 33. Therefore, when the braking rod 8 moves backward, the piston rod 33 displaces in the backward movement in proportion to the displacement and gradient of the tapered portion 8b, and the hydraulic pressure and the oil amount generated by the displacement (forward movement) of the piston 33 The hydraulic oil flows out of the front chamber of the piston into the hydraulic hose 45 'on the outward path. On the contrary, the same amount of hydraulic oil flows from the return hydraulic hose 45 into the piston rear chamber in the cylinder 30. Of course, when the braking rod 8 moves forward, the piston 33 and the piston rod 33a are moved by the coil spring 32 according to the displacement and the gradient of the tapered portion 8b. Along with the movement of the piston 33, a considerable amount of hydraulic oil flows from one hydraulic hose 45 'into the piston front chamber, and conversely, hydraulic oil flows from the piston rear chamber to the other hydraulic hose 45. .

The braking operation mechanism B is configured as a hydraulic cylinder 31 having substantially the same specifications as the hydraulic cylinder 30 of the displacement detection mechanism A. As shown in FIG. 9, the tip end of the rod 34a of the piston 34 is connected by a shaft 36 to the intermediate portion of the braking operation member 25 whose upper end is rotatably attached to the bearing 24 by the pin 27. A compression coil spring 32 for restoration operation is wound around the piston rod 34a between the piston 34 and the cylinder bracket.

Therefore, in the hydraulic cylinder 30 of the displacement detecting mechanism A, when the piston 33 moves forward while compressing and contracting the coil spring 32 in accordance with the backward movement of the braking rod 8, the hydraulic oil is pushed out to the hydraulic hose 45 ′. The piston 34 of the hydraulic cylinder 31 of the braking operation mechanism B is pushed in proportion to the amount of oil and the hydraulic pressure, and the coil spring 32 is pushed forward while being compressed. The braking operation member 25 is rotated around the shaft 27 by the forward movement of the piston rod 34a, and the free end of the braking operation member 25 contacts the head portion 10b of the braking piece 10 and pushes it down to bring it into pressure contact with the rear wheel 5 to exert a large braking force. Generate. The hydraulic oil flowing out from the piston rear chamber of the hydraulic cylinder 31 flows into the piston rear chamber of the hydraulic cylinder 30 of the displacement detection mechanism A through the hydraulic hose 45. On the contrary, when the braking rod 8 is moved forward by the coil spring 14 and the force pushing the piston rod 33a of the hydraulic cylinder 30 of the displacement detection mechanism A is reduced or eliminated, the piston 33 reacts sensitively to this and the piston 33 moves the coil spring 32. Is immediately pushed back by. As the hydraulic pressure in the piston front chamber decreases as the piston 33 moves backward, and hydraulic oil is absorbed from the hydraulic hose 45 ', the hydraulic pressure in the hydraulic cylinder 31 of the braking mechanism B decreases and hydraulic oil flows out. The piston 34 is immediately pushed back by the coil spring 32 in a sensitive manner. By the backward movement of the piston rod 34a, the braking operation member 25 is rotated in the direction for releasing the braking force, the braking piece 10 is separated from the rear wheel 5, and the rear wheel 5 is restored to a freely rotating non-braking state.

[0025]

[Other embodiments]

 (1) FIG. 10 shows an embodiment in which the piston rod 33a of the hydraulic cylinder 30 of the displacement detection mechanism A is arranged parallel to the center line of the braking rod 8 and the movement of the braking rod 8 is directly detected. . (2) The displacement detection mechanism A (including the embodiment shown in FIG. 4) may be implemented by a configuration that directly detects the movement of the tractor 6. (3) The displacement detection mechanism A directly converts the displacement of the piston rod 33a of FIG. 8 or FIG. 10, the rotation of the rotary arm 20 of FIG. 4, or the movement of the braking rod 8 or the tractor into an electric amount. Alternatively, the electric signal may be used to control the hydraulic circuit to drive and control the hydraulic cylinder 31 of the braking operation mechanism B. (4) The drive unit of the braking operation mechanism B may be configured to use the mechanical output of an electric motor, for example, an electric motor or an electromagnetic solenoid, instead of the hydraulic cylinder 31.

[0026]

[Effects of the present invention]

 In the towing vehicle according to the present invention, as soon as the driving vehicle stops during towing, braking force automatically acts on the rear wheels 5 of the towing vehicle 1, and the vehicle is sensitive to the stopping of the driving vehicle to stop. The risk of collision with another vehicle (driving vehicle, towing trolley) or swaying to the left or right with excessive momentum and meandering and disturbing the line is prevented. Also, while the vehicle is stopped, the braking state is maintained by itself, and there is no fear of inadvertent movement. Of course, no noisy impulsive noise is generated when the vehicle is stopped by braking, and there is no concern that the coupler will be damaged due to repeated collisions.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a tow truck.

FIG. 2 is a vertical sectional view of a central portion of FIG.

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG.

FIG. 4 is a plan view in which a different embodiment of the braking device is partially omitted.

5 is a side view in which the braking device in FIG. 4 is applied to a tow truck.

FIG. 6 is an enlarged cross-sectional view of a braking operation mechanism.

FIG. 7 is a right side view of FIG.

FIG. 8 is a plan view in which a different embodiment of the braking device is partially omitted.

9 is a front view showing the braking operation mechanism of FIG. 8. FIG.

FIG. 10 is a sectional view showing another embodiment of the displacement detection mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traction vehicle 11 Vehicle body 4 Front wheel 5 Rear wheel 6 Traction device 15 Coupler 8 Braking rod 10 Braking piece 9 Braking operation member 18 Frame A Displacement detection mechanism B Braking operation mechanism 23 Cable with sheath

Claims (5)

[Scope of utility model registration request] 1. A front wheel, which is a free wheel, and a rear wheel, which is a fixed wheel, are provided under a vehicle body, a tractor connected to a front vehicle is provided at a substantially central portion of a front portion of the vehicle body, and a substantially central portion of a rear portion of the vehicle body. The tractor is equipped with a coupler for connecting a tractor of a succeeding trolley to the front part of the vehicle. (A) The base end of the tractor is moved forward and backward with a constant stroke in the front and rear of the vehicle body in the traveling direction. (B) A braking rod is disposed on the front portion of the vehicle body in a position substantially parallel to the direction of forward / backward movement of the tractor, and at least the stroke of movement of the tractor in the axial direction. (C) The braking rod always receives the acting force in the direction to release the braking action of the braking piece, which will be described later, with a spring or the like. The base end of the tractor is always pushed to the forward limit position by the action force. (D) The braking piece that brakes the rear wheel is installed so that it can be brought into and out of contact with the rear wheel. (E) A braking operation member that presses the braking piece against the rear wheel. Is installed in the rear part of the vehicle body, and the braking operation member and the braking rod are connected in a series of operating relations. 2. Two rear wheels are symmetrically arranged under the vehicle body, and a braking piece for braking the rear wheel and a braking operation member for pressing each braking piece against the rear wheel are provided in one rear wheel. The two braking operation members and the braking rod on the front part of the vehicle body are installed one by one, and the two rods are moved in series by a frame body having a substantially isosceles triangular shape in plan view with the position of the braking rod as an apex. The tow truck according to claim 1, which is connected to the tow truck. 3. A front wheel, which is a free wheel, and a rear wheel, which is a fixed wheel, are provided under a vehicle body, and a tractor connected to a front vehicle is provided at a substantially central portion of a front portion of the vehicle body, and a substantially central portion of a rear portion of the vehicle body. The tractor is equipped with a coupler for connecting a tractor of a succeeding trolley to the front part of the vehicle. (A) The base end of the tractor is moved forward and backward with a constant stroke in the front and rear of the vehicle body in the traveling direction. (B) A braking rod is disposed in the front portion of the vehicle body in a position substantially parallel to the direction of forward / backward movement of the tractor, and at least the stroke of movement of the tractor in the axial direction. (C) The braking rod always receives the acting force in the direction to release the braking action of the braking piece, which will be described later, with a spring or the like. The base end of the tractor is always pushed to the forward limit position by the action force. (D) The braking piece for braking the rear wheel is installed so as to be able to come into contact with and separate from the rear wheel, (e) Detects the backward displacement of the braking rod or tractor. (F) A braking operation mechanism that presses the braking piece against the rear wheel is installed, and the braking operation mechanism is connected to the displacement detection mechanism. The towing truck is characterized in that the braking operation mechanism is driven in accordance with the displacement detected by to bring the braking piece into pressure contact with the rear wheel. 4. The tow truck according to claim 3, wherein the displacement detection mechanism and the braking operation mechanism are connected by a cable with a sheath in a relationship of transmitting mechanical displacement and force. 5. The displacement detection mechanism is configured to detect the displacement of the braking rod as a hydraulic pressure or an electric quantity, and the braking operation mechanism includes a hydraulic or electric drive section that operates based on the hydraulic pressure or the electric quantity. The tow truck according to claim 3, wherein the tow truck is configured as a mechanism having.