JPH0369836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hinged device for a forklift whose main work is handling long objects such as wood.

(Prior Art) FIGS. 8 and 9 show a conventional hinged device. As shown in the figure, a fork bar 4 for hooking and supporting a fork 3 is attached to a protrusion 2 protruding from the front lower part of the left and right lift brackets 1 via a support pin 5 so as to be tiltable back and forth. A dump cylinder 6 is vertically installed between the left and right lift brackets 1, and its piston rod is connected to a fork bar 4. By operating the dump cylinder 6 telescopically and retracting, the fork bar 4 can be tilted back and forth. The damping operation of the fork 3, that is, tilting upward and downward, is performed. Further, a backrest 7 is arranged on the fork bar 4 to receive the cargo on the fork from the rear side. , is always held in the initial position, that is, in a substantially upright state with respect to the fork 3, by the return coil spring 9.

Therefore, when the backrest 7 extends the dump cylinder 6 and tilts the fork 3 upward,
As shown in FIG. 8, by tilting relative to the fork bar 4 against the coil spring 9, the fork 3 can be tilted upward, and the dump cylinder 6 can be compressed to tilt the fork 3 horizontally or downward. 9, the fork 3 is returned to its initial position, which is substantially upright, by the tensile force of the coil spring 9, without causing the fork 3 to fall forward due to its own weight.

(Problems to be Solved by the Invention) In the hinged device described above, two left and right coil springs 9 are used as means for returning the backrest 7 to its initial position. However,
The mounting direction of the coil spring 9 cannot be made to match the direction of its action. In other words, the coil spring 9 is stretched vertically between the upper back of the backrest 7 and the upper end of the back of the fork bar 4 as shown in the figure. Due to the mounting method, it is difficult to effectively apply a desired return rotational force to the backrest 7, and as a result, a large coil spring 9 is required. By the way, during actual cargo handling work, the driver checks the front through the openings formed in the fork bar 4 and the back crest 7, and at that time, the aforementioned two left and right coil springs 9 are used to check the front. Since the coil spring 9 becomes an obstacle and has to be relatively large for the above-mentioned reason, it has the disadvantage that the forward field of view is significantly obstructed.

In view of the above-mentioned problems, the present invention aims to effectively apply a rotational force to return the backrest to its initial position, thereby improving the forward field of view, as a technical problem to be solved. .

(Means for Solving the Problem) The technical means for solving the above problem is to attach a fork bar for supporting the fork to the lift bracket so that it can tilt forward and backward, and to attach the backrest to the fork bar so that it can rotate in the front and rear directions. In a hinged device for a forklift, in which a torsion bar is horizontally arranged near the upper end of the fork bar, one end of the torsion bar is fixed or engaged with the fork bar side, and the other end is fixed or engaged with the backrest side. This is because the backrest is biased in the upright direction of the initial position.

(Function) Therefore, when the fork tilts upward from the horizontal state, the back crest responds to the upward tilting operation of the fork by tilting relative to the fork bar against the torsion bar, and also prevents the fork from returning to the horizontal state from the upward tilting state or When it is tilted downward, it is returned to its initial upright position by the rotational force applied by the torsional force of the torsion bar.

(Example 1) Hereinafter, Example 1 of the present invention will be specifically described based on FIGS. 1 to 3. Furthermore, Fig. 3 is a schematic side view of the hinged device installed on the forklift, and the hinge mechanism that enables the damping operation of the fork to tilt upward and downward is exactly the same as the conventional one. The mechanism will be briefly explained using the same reference numerals as in the prior art. That is, a fork bar 4 for supporting a fork 3 is pivotally attached via a support pin 5 to the lower front surface of a lift bracket 1 that is moved up and down along a mast 10 of a forklift so as to be tiltable forward and backward. The fork 4 is tilted forward and backward by the expansion and contraction operation of a dump cylinder 6 vertically arranged between the left and right lift brackets 1, thereby causing the fork 3 to perform a damping operation.

Next, we will discuss the main part of the present invention, the backrest 7.
The mounting structure will be explained based on FIGS. 1 and 2. However, in FIGS. 1 and 2, the lift bracket 1 and dump cylinder 6 are omitted, and the second
In the figure, the backrest 7 is shown by a virtual line. As shown in the figure, the backrest 7 is pivotally attached to the upper end of the fork bar 4 by a support pin 8 so that both left and right ends can be tilted forward and backward. A torsion bar 11 that holds the back crest 7 in an upright position as an initial position is horizontally arranged on the upper surface of the upper bar 4a of the fork bar 4. One of the torsion bar brackets 12 is fixed by a lock pin 13, and the other torsion bar bracket 12 is rotatably supported. An engagement piece 15 is provided at the end of the torsion bar 11 that is allowed to rotate (the right end in FIG. 1) and comes into contact with a contact plate 14 attached to the backrest 7. Engagement piece 1
5 is brought into contact with the front surface of the contact plate 14 with the torsional force of the torsion bar 11 applied in advance to prevent the backrest 7 from wobbling when the fork 3 is tilted downward. That is, the backrest 7 is given a rotational force in the backward tilting direction by the torsion bar 11, and the end of the rotation in that direction is such that the lower end of the backrest 7 hits the stopper 16 that is provided protruding from the upper surface of the lower bar 4b of the fork bar 4. It is regulated by contact.

This embodiment is configured as described above,
Therefore, when the fork 3 is in a horizontal state, the backrest 7 is held at an initial position substantially upright with respect to the fork 3. When the fork 3 is tilted upward, the backrest 7 once retreats to the position where it contacts the lift bracket 1 as the fork bar 4 tilts backward, and after the backrest 7 is restricted from retreating, it moves around the support pin 8 to the fork bar 4 while twisting the torsion bar 11. By tilting relative to the other hand, the fork 3 corresponds to the upward tilting motion. Further, when the fork 3 returns from the upwardly tilted state to the horizontal state or when the backrest 7 tilts downwardly, the backrest 7 is given a rotational force in the backward tilting direction by the torsional force of the torsion bar 11, and the backrest 7 is initially in an almost upright state with respect to the fork 3. Rotate back to position.

Note that the torsion bar 11 has one end fixed to the backrest 7, and the other end fixed to the fork bar 4 with the engagement piece 1.
The same effect can be achieved even in the case where the contact is made through the contact point 5.

(Other Embodiments) Next, other embodiments of the present invention will be described. In all the embodiments described below, the torsion bar 11 also functions as a support pin for tilting the backrest. First, Example 2 shown in FIGS. 4 and 5 will be explained.
The torsion bar 11 is arranged horizontally at the upper end of the fork bar 4, and its left and right ends are fixed to the fork bar 4 by lock pins 17. is rotatably supported, and a connecting bracket 18 provided at the center of the backrest 7 is fitted onto the torsion bar 11 and fixed by a lock pin 19. That is, the backrest 7 in the second embodiment is rotatably supported on both sides by torsion bars 11 supported at both ends, and the center portion is fixed.

Embodiment 3 shown in FIG. 6 is a cantilever type torsion bar 11 that is double-sided as described above, and a fork bar 4 is fixed to one end of the torsion bar 11 with a lock pin 17.
A backrest 7 is fixed to the other end with a lock pin 19.

Furthermore, the fourth embodiment shown in FIG. 7 uses two symmetrically arranged torsion bars 11, and as shown in the figure, each torsion bar 11
has a horizontal part of a predetermined length at one end, and is rotatably supported by both left and right ends of the fork bar 4 with this horizontal part aligned with the same axis, and is arranged in a cross shape so as not to interfere with each other inwardly. It extends and its end is fixed to the fork bar 4. Both sides of the backrest 7 are fitted into the horizontal portions of each torsion bar 11, and are fixed by lock pins 19.

Therefore, in any of the second, third, and fourth embodiments described above, the backrest 7 is tilted or returned to the initial position by the torsion bar 11 in response to the damping action of the fork 3, as in the first embodiment described above. You can

Note that the means for fixing the torsion bar 11 to the fork bar 4 or the backrest 7 is not limited to the illustrated lock pin, and may be any other method such as welding, splines, screws, etc.

(Effects of the Invention) As detailed above, the present invention arranges the torsion bar horizontally near the upper end of the fork bar,
This gives the backrest a rotational return force to its initial position, which reduces the degree of obstruction to the forward field of vision compared to the conventional system in which two coil springs are arranged vertically. In particular, since the torsional force of the torsion bar can be effectively used as the return rotational force of the backrest, it is possible to reduce the torsion bar to the minimum necessary range. For this reason, the forward field of view is improved, which is extremely effective in improving work efficiency and safety.

As explained in the other embodiments, when the torsion bar is configured to also serve as a support pin for the backrest, the number of parts can be reduced and the entire hinged device can be made more compact.

[Brief explanation of drawings]

FIG. 1 is a front view showing Embodiment 1 of the hinged device of the present invention, FIG. 2 is a side sectional view of the same, FIG. 3 is a schematic side view of the hinged device mounted on a forklift, and FIG. 4 is a front view of the hinged device of the present invention. 5 is a front view showing the second embodiment of the invention, FIG. 5 is a sectional view taken along the line -- in FIG. 4, FIG. 8 and 9 are side views showing a conventional example. 1... Lift bracket, 3... Fork, 4... Fork bar, 7... Back crest, 11... Torsion bar.

Claims (1)

[Scope of Claims] 1. In a hinged device for a forklift, in which a fork bar for supporting a fork is pivotally connected to a lift bracket so as to be tiltable forward and backward, and a backrest is pivotally connected to the fork bar so as to be tiltable forward and backward, the fork bar is located near the upper end of the fork bar. A hinged device for a forklift, in which a torsion bar is horizontally arranged, one end of the torsion bar is fixed or engaged with a fork bar side, and the other end is fixed or engaged with a back crest side to bias the back crest in an upright direction at an initial position. 2. The hinged device for a forklift according to claim 1, wherein the torsion bar is arranged on the tilting center line of the backrest and also serves as a support pin for tilting the backrest.