JPH0521442Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a coupling device for a towing tractor used for towing a trailer, etc., and more specifically relates to a two-stage coupling device of upper and lower stages.

(Prior art) The above-mentioned two-stage upper and lower coupling device has different heights for the tow bar (connecting rod) installed on the trailer side depending on whether it is large or small. It was formed to accommodate the height difference of the toe bar. Furthermore, in addition to the heights of the tow bars being different, the sizes of the holes in the tow bars may also be different, and in such cases, the drawbars are provided with stepped pins.

FIG. 4 shows a conventional two-stage connecting device using stepped pins. This coupling device consists of three upper and lower plates 31, 3 on the rear part 30 of the vehicle body.
A drawbar bracket 34 consisting of 2 and 33 is provided, a drawbar 35 consisting of a stepped pin is attached to the drawbar bracket 34 so as to be movable up and down, and a drawbar lever 37 is operated by tilting an operation lever 36 attached to the upper part of the rear of the vehicle body. The drawbar 35 is pulled upward via the link 38.

(Problem to be solved by the invention) However, in the case of the conventional coupling device described above, when the drawbar 35 is pulled up, the drawbar 3
When the large diameter portion of the drawbar 35 passes through the pin hole of the upper plate 31, the drawbar 35 is tilted as shown in the imaginary line in the figure.
It may get caught on the edge of the hole at the arrow position. In order to prevent this catching, the hole diameter of the middle plate 32 can be made larger, but in that case, the play between the drawbar 35 and the drawbar 35 will be large, and since the hole diameter of the lower plate 33 is fixed, the drawbar 35 will be 33, resulting in a so-called cantilevered structure. Further, the step portion of the drawbar 35 requires a tapered portion, and the existence of this tapered portion causes problems such as the necessity to set a wide interval between the middle plate 32 and the lower plate 33.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved coupling device for a towing tractor, which eliminates the drawbacks of the conventional devices mentioned above.

(Means for solving the problem) The present invention for solving the above problem consists of the upper, middle,
In a coupling device of a type in which a drawbar is vertically movably attached to a drawbar bracket consisting of three lower plates to form a two-tiered coupling section, the drawbar has a length that allows the drawbar to pass through all the plates. A double pin structure is formed by a small-diameter inner pin and a large-diameter cylindrical outer pin having approximately half the length of the inner pin and fitted so as to be movable relative to the inner pin, while the middle plate A stepped pin hole consisting of a small diameter portion through which the inner pin passes and a large diameter portion into which the outer pin fits is formed in the stepped pin hole, and the lower end of the outer pin is received by the stepped portion of the stepped pin hole. The gist is that a stopper part is formed at the lower end of the inner pin to pull up the outer pin when it passes the middle plate during its upward movement.

(Function) When the operating lever is operated to pull out the drawbar, the inner pin is first moved upward, and then when the inner pin passes through the middle plate, the stopper part of the inner pin comes into contact with the lower end of the outer pin. After that, the outer pin and the inner pin are moved upward as a unit. In other words, even when the drawbar is pulled up, the large diameter outer pin fits into the pin hole of the upper plate, so the drawbar is held upright without tilting.
The subsequent lowering action of the draw bar will be smooth with no catch occurring on the way.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings. FIG. 3 schematically shows a towing tractor, in which the coupling device 1 is installed at the rear of the vehicle body. This coupling device 1 will be explained based on FIGS. 1 and 2. In the figure, 2 is a drawbar bracket fixed to the rear end surface 3 of the vehicle body, and this drawbar bracket 2 is a vertical plate fixed to the rear end surface 3 of the vehicle body. 4, and three upper, middle, and lower plates 5, 6, and 7 fixed horizontally to the vertical plate 4 at predetermined intervals in the vertical direction, and these three plates 5, By attaching the drawbar 8 to 6 and 7 so as to be able to move up and down, the upper and lower 2 have connecting parts on the upper and lower sides.
A stage-type coupling device 1 is configured.

The drawbar 8 has a small-diameter inner pin 9 having a length that can pass through the three plates 5, 6, and 7, and a large-diameter cylindrical outer pin through which the inner pin 9 is inserted so as to be relatively movable. It has a double pin structure with different diameters from 10. The outer pin 10 has approximately half the length of the inner pin 9, and passes through the large diameter pin hole 5a formed in the upper plate 5, while passing through the large diameter stepped pin hole 6a formed in the middle plate 6. and is supported by the stepped portion. On the other hand, the inner pin 9 is provided with a vertical plate-shaped stopper plate 11 at its upper end, which is fixed to the upper surface of the upper plate 5.
0 and is fitted into the small diameter portion of the stepped pin hole 6a of the middle plate 6 and the small diameter pin hole 7a formed in the lower plate 7. In addition, at the lower end of the inner pin 9 there is a dent pin 12 that penetrates in the radial direction.
is provided, thereby forming a stopper portion for pulling up the outer pin 10. In addition,
Relief grooves 12a are provided in the pin hole 7a of the lower plate 7 and the small diameter portion of the stepped pin hole 6a of the middle plate 6, respectively, so that the cotter pin 12 can pass therethrough.
is formed.

An operating lever 13 for operating the drawbar is attached to the rear upper part of the vehicle body via a bracket 14 so as to be tiltable around a pin 15. A drawbar lever 16 is integrally connected to the tip of this operating lever 13, and the drawbar A link 18 is connected to the lever 16 by a pin 17 through an elongated hole 16a, and is connected to the stopper plate 11 of the inner pin 9 by a pin 19.

This embodiment is configured as described above,
Therefore, when the operating lever 13 is tilted to pull out the drawbar 8, the inner pin 9 connected to the drawbar lever 16 and the link 18 is pulled out, and the lower end of the inner pin 9 is attached to the lower surface of the middle plate 6. When the towbar 20a of the small trailer is pulled up to the lower level, the tow bar 20a of the small trailer
can be connected to the inner pin 9.

Furthermore, if the inner pin 9 is pulled up further from this state, the cotter pin 12 will come into contact with the lower end surface of the outer pin 10 when the inner pin 9 passes through the middle plate 6, so after that the outer pin 10 will be pulled out. The tow bar 20b of the large trailer can be connected to the outer pin 10 at the upper connecting portion at the maximum pulling-out position where the upper plate 5 has been pulled up to near the lower surface of the upper plate 5.

As shown by the imaginary line in FIG. 1, when the drawbar 8 is in its maximum pulled-out state, the large-diameter outer pin 10 is fitted into the pin hole 5a of the upper plate 5, so the drawbar 8 is tilted. Therefore, the subsequent lowering operation of the drawbar 8 can be performed smoothly without getting caught in the middle.

In addition, in this embodiment, the stopper part for pulling up the outer pin 10 was formed by the cotter pin 11.
The structure is not limited to this, and the structure may be such that the protrusions are fixed by welding as appropriate.

(Effects of the invention) As detailed above, the coupling device of the invention has a drawbar with a double pin structure of different diameters consisting of a small-diameter inner pin and a large-diameter cylindrical outer pin that is fitted into the drawbar. This allows the drawbar to be held upright when it is pulled up to its maximum, making it possible to smoothly lower the drawbar afterwards, which is different from conventional devices that use stepped pins. Unlike this, the hole diameters of the drawbar and the plate can be set without wobbling, allowing the drawbar to be supported at both ends, and there is no need for a tapered part such as a stepped pin, so there is no need for a gap between the middle plate and the bottom plate. Can be set to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the coupling device of the present invention, Fig. 2 is a plan view with the operating system omitted, Fig. 3 is a schematic side view of a towing tractor, and Fig. 4 is a conventional coupling device. FIG. 2 is a side sectional view showing the device. 1... Connection device, 2... Drawbar bracket, 5, 6, 7... Upper, middle, lower plates, 6a
...Stepped pin hole, 8...Draw bar, 9...Inner pin, 10...Outer pin, 12...Kotta pin.

Claims (1)

[Scope of utility model registration request] In a coupling device of the type in which a drawbar is attached to a drawbar bracket consisting of three plates (upper, middle, and lower) so as to be movable up and down to form a two-tiered coupling section, the drawbar has a length that can pass through all the plates. A double pin structure is formed by a small-diameter inner pin having a length and a large-diameter cylindrical outer pin having a length approximately half that of the inner pin and fitted so as to be movable relative to the inner pin. A stepped pin hole is formed in the middle plate, and the stepped pin hole includes a small diameter portion through which the inner pin passes and a large diameter portion into which the outer pin fits, and the lower end of the outer pin is received by the stepped portion of the stepped pin hole. and a stopper portion is formed at the lower end of the inner pin to pull up the outer pin when the inner pin passes the middle plate during upward movement.