JPS63272787A - Back rest positioning device for forklift - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a forklift backrest positioning device.

Conventional technology For example, Utility Model Publication No. 49-2367 was developed to facilitate the loading and unloading of cargo using forks in deep places.
As shown in the publication, there are known forks in which the fork itself can be moved forward and backward using a pantograph mechanism, or a backrest is fixed to a sheath attached to the fork, so that the sheath can be adjusted forward and backward together with the backrest. ing.

Problems that the invention aims to solve Even though it is possible to load and unload cargo in deep places, if the pallet is shorter than the length of the fork claws, the tips of the fork claws may be in front of the pallet. This protruding claw tip can damage preloaded cargo or pallets or cause the cargo to collapse. Furthermore, the movement of the fork or sheath mentioned above is carried out by a hydraulic cylinder, but when additional cargo collides with the backrest due to air bubbles mixed in the hydraulic oil and looseness of the link mechanism, the backrest moves forward and backward. There is a risk of the load shifting slightly and causing the load to collapse. Therefore, the present invention makes it possible to easily adjust the actual length of the fork even if the fork needs to be replaced according to the length of the pallet.
To provide a backrest positioning device for a forklift that can prevent slight movement of the backrest between the front and rear even if a loaded load collides with the backrest.

One way to solve the problem is to install a pair of guide masts on a carriage equipped with a fork, and slide up and down a slider that connects the rear ends of the upper and lower links to the upper and lower ends of these guide masts. While freely attached, the front ends of the upper link and the lower link are connected to a backrest above the fork pawl at a position offset downward from the connection point with the slider to form a parallel link mechanism. 1. A cylinder mechanism is installed vertically across the MJ guide mast and the parallel link mechanism to extend and contract the core parallel mechanism to move the backrest forward and backward on the fork pawl, and The rest and the carriage are provided with guide means that slide against each other near the retraction limit of the backrest and lift the backrest obliquely upward as the backrest moves backward.

The parallel link mechanism expands due to the expansion and contraction of the action cylinder mechanism.
The positioning is performed by retracting the backrest and advancing and retracting it on the fork pawl, and the actual weight of the fork is adjusted.

When a load collides with the backrest, these upper links connect to the upper and lower links of the backrest.

A component of force acts diagonally downward at right angles to the lower link, pressing the backrest onto the claw and preventing slight movement of the backrest. When the backrest is moved to the rearward limit position, the guide means slide into contact with each other near the rearward limit, causing the backrest to tilt diagonally upward as the backrest moves backward.

Example Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In Figures 1 to 3, 1 shows a carriage with a fork 3 attached to a finger par 2;
On the front of the finger bar 2, the upper end is attached to the upper beam 5.
A pair of guide masts 4 each having a U-shaped cross section are arranged. Reference numeral 6 denotes a slider that is fitted and attached to these guide masts 4 so as to be able to slide vertically, and an upper link 7 is provided at each upper and lower end.
, the rear end of the lower link 8 is connected to the pin 9.10.

The left and right upper links 7 and lower links 8 are connected at their intermediate portions by reinforcing beams 11 and 12, and the front ends of each upper link 7 and lower link 8 are connected to the pawls 3 of the fork 3.
The backrest on a) 15 is connected to the bins 13, 14 at an offset position below the connection point with the slider 6, and the slider 6, upper link 7, lower link 8.
C17, which constitutes the parallel link mechanism 16 with the backrest 15, is a cylinder mechanism that is arranged in the vertical direction astride the guide mast 4 and the parallel link mechanism 16, and in this embodiment, the cylinder body 17a is connected to the guide mast 4. The pin 19 is connected to a bracket 18 provided on the middle of the upper beam 5, and the operating rod 17b is connected to the reinforcing beam 1 of the lower link 8.
2. A bottle 21 is connected to a bracket 20 provided at the center, and the cylinder mechanism 17 is extended and contracted in parallel.
6 is extended and contracted, and the backrest 15 is moved forward and backward on the claw 3a of the oak 3. Reference numeral 22 indicates a guide means for lifting the backrest 15 obliquely upward as the backrest 15 moves backward from near the backward limit of the backrest 15. The slope piece 23 is attached to the end of a bracket 25 that is connected to the center of the lower end of the backrest 15 and protrudes rearward;
The guide bin 24 rides on and slides onto the tip of the slope piece 23 near the retraction limit of the slope piece 5.

According to the apparatus of the above embodiment, the cylinder mechanism 17 is extended,
When the retraction operation is performed, the slider 6 of the parallel link mechanism 16 slides vertically within the guide mast 4, and the parallel link mechanism 16
extends and contracts, allowing the backrest 15 to advance or retract on the claw 3a of the fork 3. As a result, the pawl 3a of the fork 3
The actual length, that is, the length L from the tip of the claw 3a to the backrest 15, is the length of the pallet or cargo (this example shows the case of cargo W) as shown in Figure 4.5. It can be arbitrarily divided according to the requirements. On the other hand, when the load W is taken onto the claw 3a, if the load W collides with the backrest 15 and an external force F acts rearward on the backrest 15, the upper link 7 of the backrest 15 A component force (fl) acts obliquely downward at right angles to the upper link 7 and the lower link 8 at the connecting portion of the lower link 8, thereby pressing the backrest 15 onto the claw 3a. Therefore, even if the parallel link mechanism 16 has looseness in the connecting portions of each bottle, or even if air bubbles are mixed in the oil in the cylinder machine [17 and the oil lock is not completely formed, the backrest 15 will not move over the claw 3a. The backrest 15 can be reliably positioned by preventing the backrest 15 from slightly moving rearward. On the other hand, in case the backrest 15 is moved backward to the backward limit position where it comes into contact with the guide mast 4, the cylinder mechanism 17 is disposed vertically across the upper beam 5 and the reinforcing beam 12 of the lower link 8. , this cylinder mechanism 17 is arranged in the vertical direction in a state close to parallel to the lower link 8. Therefore, this backrest 15
When attempting to move the backrest 15 forward by extending the cylinder machine '11t17 from the backward limit position of the cylinder machine 11t17 to extend the parallel link mechanism 16, the component force in the direction of extending the parallel link mechanism 16 becomes small. There is a tendency. However, when the backrest 15 is moved backward and the backrest 15 reaches the vicinity of the backward limit, the guide bin 24 of the guide means 22 rides on the tip of the slope piece 23 and comes into sliding contact with it. With the backward movement, the backrest 15 is lifted diagonally upward. As a result, when the backrest 15 is moved forward from its backward limit position by extending the cylinder mechanism 17, the guide pin 24 slides on the slope piece 23 and moves downward due to the weight of the backrest 15. Therefore, the initial forward movement of the backrest 15 can be performed smoothly.

In the embodiment shown in FIG. 6, a contact 26 is attached to the bottom surface of the backrest 15 at a position offset rearward from the connection point of the lower link 8 and makes point contact or line contact in the width direction with the surface of the claw 3a. be. In this embodiment, since the contactor 26 is located at the rear of the connection point of the lower link 8 of the backrest 15 as described above, it is particularly difficult to move the backrest 15 forward from the aforementioned backward limit position. , the guide pin 24 slides down on the slope piece 23, and the contactor 26
When the contact 26 collides with the pawl 3a, the contact 26 slides on the pawl 3a at the rear of the input application point from the lower link 8.
The initial forward movement of the backrest 15 can be performed even more smoothly.

Effect of the invention As described above, according to the present invention, there is provided a cylinder mechanism.

By moving the backrest forward and backward on the fork pawl using a parallel link mechanism, the actual length of the fork can be arbitrarily adjusted according to the length of the pallet being used. It is possible to avoid damaging pre-loaded cargo or pallets with the tips of the nails. Furthermore, even if you want to replace the fork itself or use the sheath, you can easily adjust the length of the claws, so work efficiency can be significantly improved. Furthermore, there is an upper link with a parallel link mechanism.

Each connection point between the lower link and the backrest is offset downward from the connection point with the slider of the guide mast, and if the load collides with the backrest,
Since the component force acts in the direction of pressing the bottom surface of the backrest onto the claw of the fork, slight movement of the backrest in the front and back direction can be prevented and positioning can be performed reliably.

When the backrest moves to the retracting limit position where it contacts the guide mast, the cylinder mechanism stands up and the link efficiency that extends the parallel link mechanism tends to deteriorate. The backrest is lifted diagonally upwards by the guide means from near the limit position, and when the backrest is moved forward from the retraction limit position, the backrest is moved diagonally forward downwards to smooth the initial forward movement of the backrest. This has a great practical effect in that it can be carried out in a number of ways.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the present invention, Fig. 2 is a front view of the backrest cut in half, and Fig. 3 is the n of Fig. 1.
4 and 5 are schematic side views showing the operating state of the present invention, and FIG. 6 is a schematic side view showing a different example of the present invention. 1・e@carriage, 3s age-fork, 3a--claw, 4...guide mast, 6φ...slider, 7.00
．． Upper link, 8.・, Lower link, 15., φ backrest, 16.--Parallel link mechanism, 17.
Cylinder mechanism, 22... guide means. 2 people outside Figure 3 Figure 4 Figure 1? 1,8 1-ichiichiya! 1 3-m-Foot 3G-claw 4-One-to-one eye 6--Slyno Figure 2 knob 7--71 Sono V lift 8--Lower link 15--Backrest 7th stroke 161--parallel ring lecture r"17--"y ring evening 11 corner 22--guy l-! handmade candle

Claims (1)

[Claims] (1) A pair of guide masts are arranged on the carriage on which the fork is attached, and a slider, which connects the rear ends of the upper link and the lower link at the upper and lower ends, is attached to these guide masts so as to be able to freely slide up and down. , the front ends of the upper link and the lower link are connected to the backrest on the fork pawl at a position offset downward from the connection point with the slider to form a parallel link mechanism, and A cylinder mechanism is attached to the parallel link mechanism in the vertical direction to extend and contract the parallel link mechanism to move the backrest forward and backward on the fork pawl, and the backrest and the carriage are provided with a cylinder mechanism that extends and contracts the parallel link mechanism to move the backrest forward and backward on the fork pawl. A backrest positioning device for a forklift, comprising guide means that slide against each other near the limit and lift the backrest obliquely upward as the backrest moves backward.