JPS5918320B2 - Reach fork longitudinal movement mechanism of forklift truck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reach fork back and forth movement mechanism of a forklift truck, and is particularly suitable for loading (or unloading) cargo located deep inside a rack shelf or container with a low opening height. This relates to the structure of the reach fork back and forth movement mechanism.

A typical structural example and operating state of a conventional reach fork are schematically shown in FIGS. 1 and 2.

Fig. 1 shows the reach fork in a backward state, and Fig. 2 shows the reach fork in a forward state.

In Figures 1 and 2, 1 is the body of a forklift truck, 2 is its front wheel, 3 is a mast, and 4 is a rear part that is attached to a lift bracket (not shown in this figure) and moves up and down on the front surface of the mast 3. Rail 5 is a front rail that moves back and forth parallel to the rear rail 4; 6. T denotes a first link and a second link which are rotatably fixed to the lower end of the front rail and rear rail, respectively; 8 is fixed to the lower end of the rear rail 4; A shaft 9 is fixed to the lower end of the front rail 5 and rotatably supports the link T, and 10 is a shaft that rotatably supports the first link 6. Second link 1
The axes 11 and 12 connecting the respective midpoints of are located at the upper end (second end) of the first link 6° and the second link γ, respectively, and are connected to the respective rear rails via rollers (not shown in this figure). 4° When moving up and down along the front rail 5, 13 is a fork attached to a fork bar (not shown in this figure) attached to the front rail, and 14 is a fork that is attached to the fork at the midpoint of the fork loading surface. Considered as the load center line.

From the retracted state shown in FIG.
The shaft 12 rotates around , and the shaft 12 moves forward while drawing an arc as shown by the arrow in FIG. 2, that is, while decreasing its height.

As a result, the first link 6. The front rail 5 moves forward in parallel together with the fork 13 by the link mechanism including the second link γ, etc., and enters the forward state shown in FIG. 2.

Of course, the opposite movement can also be performed. In other words, when looking at the front wheel grounding point as the reference point, the cargo is located between Ll and 2nd as shown in Figure 1.
It moves back and forth by the difference in distance from L2 shown in the figure.

In order to increase this longitudinal movement distance, it is possible to connect two or more X-shaped link mechanisms, but this would be complicated, so the first link 6. It is necessary to make the second link T longer, and the front rail 5. It is also necessary to make the rear rail 4 higher.

However, moving the fork forward to load or unload cargo is hereinafter referred to as reach work.

), as shown in FIG. 2 L2Vc, the distance from the front wheel grounding point to the load center line increases, leading to an increase in forward rotational moment' and a decrease in stability.

Therefore, cargo that can be used for reach work is generally lightweight and therefore has a small packaging size.

As a result, cargo is often stored on rack shelves with low opening heights.

However, since the upper shelf and the upper part of the front rail 5 interfere with the cargo at the back of the shelf, the busy fork 13 cannot reach it and reach work is impossible.

The present invention eliminates this drawback and provides a reach fork forward and backward movement mechanism that can reach even cargo at the back of a rack shelf with a low opening height.

The gist is that the rear rail is installed almost parallel to the mast installed in front of the forklift truck, the front rail is placed parallel to the rear rail in front of the rear rail, and the middle part can rotate relative to each other. has a first link and a second link connected to the front rail and the second link, the first ends of each of which are rotatably fixed to the lower ends of the front rail and the rear rail, respectively, and the second ends of the links are respectively on opposite sides. a link mechanism that is vertically movably engaged with a portion above the link fixing portion of the rail, and that moves the front rail back and forth by relative rotation of the first link and the second link by an actuator. In the reach fork longitudinal movement mechanism, the front rail is divided into two rails, an upper rail and a lower rail, and the upper rail is connected to the lower rail so as to be movable up and down along the longitudinal direction of the lower rail. , and by rotatably fixing the first end of the first link to the lower rail and the second end of the second link to the upper rail, the total height of the front rail becomes equal to that of the front rail. The point is that it gets lower as you move forward.

An embodiment of the present invention will be described below with reference to the drawings.

Parts that are the same as or similar to the reach fork parts of the previous type are given the same reference numerals, and descriptions thereof will not be repeated.

Figure 3 is a perspective view of the front rail, which is composed of two rails, upper and lower, and its adjacent parts, Figure 4 is a vertical cross-sectional view of the front rail in a retracted state, and Figure 5 is a front rail that is attached to the upper end of the upper rail. Fig. 6 is a perspective view showing the support state of the rollers attached to the upper rail, and Fig. 1 shows the state of the front rail when the front rail is moved forward. An explanatory diagram showing a state in which the total height is reduced to h and reach work is possible at a location where the opening height is low. FIG. 8 is a perspective view of the embodiment in another guiding state of the upper rail.

In Fig. 3, 5a is the upper rail of the front rail consisting of two upper and lower rails, and 5b is the lower rail, and the height is not significantly higher than the height of the upper end of the upper rail when it is lowered as described later when reaching. Lower rail with U-shaped cross section, 1
2a is a shaft connecting the upper ends of the left and right upper rails 5a;
are vertically spaced apart from each other at the bottom of the upper rail 5a, and are always engaged with the lower rail 5b, so that the upper rail 5a is always engaged with the lower rail 5b.
a pair of rollers that guide the vertical movement along b;
6 is a roller provided on the shaft 12a and can engage with the lower rail 5b; 11 is a shaft that connects the lower ends of the left and right upper rails and supports one of the pair of rows 215; 1;
8 is a flange that is made integrally with the shaft 1γ and connects the shaft 11 and the upper rail 5a; 19 is a fork bar that connects the left and right lower rails 5b and supports the fork 13; 20
is the backrest.

In FIG. 4, 21 is a lift bracket that moves up and down along the mast 3, 22 is a reach cylinder as an actuator that relatively rotates the link 6°T, and 23 is a shaft 8 fixed to the lift bracket 21 at the lower end of the rear rail 4. 24 is a bracket that is fixed to the fork par 19 at the lower end of the front rail and supports the shaft 9; 25 is a shaft 11 that guides the upper end of the link 6 along the rear rail 4;
It is a roller provided on the top.

In FIGS. 5 and 6, 26 is a bush fitted into the link T and the bushing between the shaft 12a, and 27 is the upper rail 5a.
a boss 28 fixed to the upper end and having a hole into which the shaft 12a is fitted;
is fixed near the lower end of the upper rail 5a, and the lower rail 5
a bub supporting one of the rows 215 constantly engaged with b;
9 is a pin that fastens the shaft 12a and the boss 2T, 30 is a wheel that holds the roller 16 on the shaft 12a, and 31 is a flange 18.
These are bolts that secure the upper rail 5a to the upper rail 5a.

In FIG. 8 showing an example of another guiding state of the upper rail, 5a' is an upper rail having a U-shaped cross section, and 12b connects the upper ends of the left and right upper rails 5a', but unlike 12a, they are guided coaxially. The shaft 32, which does not have a lawn, is a roller fixedly attached to the upper end of the lower rail, engaging with the upper rail 5a' and guiding the upper rail.

Next, the effect will be explained.

FIG. 4 shows a state in which the fork 13 is retracted, the upper rail 5a is at the uppermost position, overlaps with the lower rail 5b only by the distance between the rollers 15, and the total height of the front rail is H. .

When the reach cylinder 22 is operated now, the second link T rotates about the shaft 8 as shown by the arrow in FIG.

Accordingly, the shaft 11 at the upper end of the first link 6, which is connected to the second link γ by the shaft 10, descends, and the shaft 9 at the lower end of the first link 6 moves forward.

The shaft 12a at the upper end of the second link descends while moving forward.

As the shaft 12a descends, the upper rail 5a moves towards the lower 2
15 and descends along the lower rail 5b.

Therefore, the total height of the front rail decreases as the fork moves forward, and when the fork moves forward the entire upper rail 5a overlaps the lower rail 5b, as shown in FIG. 1, and the total height of the front rail reaches the minimum value. become.

When moving the fork backwards, reverse this movement and move the 4th
As shown in the figure, the fork is in the shortest position at the rear, and the front rail height is the maximum value H.

In the embodiment shown in FIG. 8, the upper rail 5a/ is a guide row 23 fixedly attached to the upper end of the lower rail 5b.
2 and the row 21 provided on the shaft 1T at the lower end of the upper rail.
5, it is guided to move up and down.

Since no roller corresponding to the roller 16 is provided on the extension of the shaft 12b, when the upper rail 5a' is lowered, the first
As shown in the figure, it completely overlaps with the lower rail 5b, and the total height of the front rail is reduced to h.

The rear rail 4 can also be made into two stages like the front rails 5a and 5b of the present invention, and the field of view is improved.

To describe the effects of the present invention, conventionally, when performing reach work, the total height of the front rail was H as shown in FIG. Since the height of the reach fork of the present invention is significantly higher than the length of the fork, it was not possible to handle cargo on shelves with low openings other than within the length of the fork, making reach work impossible.However, with the reach fork of the present invention, As shown in , the total height of the front rail is h, so even if the opening height h' is low, reach work is possible, and even cargo at the back of the shelf can be handled, which significantly improves cargo handling efficiency.

Warehouses can also have lower shelf heights and larger depths, increasing the amount of cargo that can be stored, which has a large economic effect.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the structure of a conventional reach fork with the fork 13 retracted, Fig. 2 is a side view showing the structure with the fork 13 moved forward, and Fig. 3 is a side view showing the structure with the fork 13 moved forward. FIG. 4 is a vertical cross-sectional view showing the front rail in the embodiment of the present invention and its adjacent portion; FIG. 4 is a vertical cross-sectional view showing the front rail in a retracted state; and FIG. 5 shows the state in which the rollers attached to the upper end of the upper rail are supported. Fig. 6 is a perspective view showing the state in which the rollers are supported on the upper rail, and Fig. 1 is a partial plan view showing the state in which the rollers are supported on the upper rail. (or loading/unloading) is an explanatory diagram showing that loading/unloading is possible. Figure 8 is a perspective view (partially broken) showing another aspect of the upper rail.
It is. 1: Forklift vehicle body, 2: Front wheel, 4: Rear rail, 5a, 5a': Upper rail, 5b: Lower rail,
6. l: link, 12a: shaft connecting the upper end of the upper rail and the upper end of link T, 13: fork, 15: roller, 1T
: Shaft connecting the lower end of the upper rail, 19: Fork bar,
20: Backrest, 21: Lift bracket, 22:
Reach cylinder % 32: Roller.

Claims (1)

[Claims] 1. A rear rail provided substantially parallel to a mast erected in front of a forklift truck, a front rail disposed in front of the rear rail in parallel with the rear rail, and an intermediate portion thereof. It has a first link and a second link connected so as to be relatively rotatable, and each first end of each of the links is rotatably fixed to the lower end of the front rail and the rear rail, respectively, and the second end of the link is rotatably fixed to the lower end of the front rail and the rear rail. are vertically movably engaged with a portion above the link fixing portion of the rail on the opposite side, and the first link and the second link are relatively rotated by an actuator to move the front rail back and forth. In the reach fork longitudinal movement mechanism, the front rail is divided into two rails, an upper rail and a lower rail, and the upper rail is connected to the lower rail in the longitudinal direction of the lower rail. connected so as to be movable up and down along the line, and
By rotatably fixing the first end of the first link to the lower rail and the second end of the second link to the upper rail, the total height of the front rail is increased by the height of the front rail. A reach fork forward and backward movement mechanism characterized by being lowered as the reach fork moves forward.