JPH11116195A - Mast device of forklift truck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-stage full free mast, in which a lift chain or hydraulic hose fitted to various attachment are precluded from constituting an obstacle for the operator's field of view as much as practicable. SOLUTION: A chain wheel 19 for a lift chain 20 mounted on the rod tip of a free lift cylinder 18 through a chain wheel bracket 42 is arranged aslant, and when viewed on the plan, is positioned on the line Q tying the axis of the free lift cylinder 18 to a chain anchor bolt 22a on the side with lift bracket 12. The wheels 43 and 44 of hoses 45 and 46 for supplying the attachment oil pressure to be installed parallel with the chain wheel 19 are alike arranged aslant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mast device for a forklift truck, and more particularly to a structure of a three-stage mast which is formed as a full free mast and in which a lift cylinder and a free lift cylinder are independent on the left and right. .

[0002]

2. Description of the Related Art A so-called wide field of view mast for widening the forward field of view of an operator has been proposed.
Is described in Japanese Patent Application Publication No. In this conventional mast device, a pair of left and right lift cylinders is disposed behind the corresponding left and right outer masts, and a pair of left and right free lift cylinders for independently lifting and lowering a lift bracket (carriage) are provided on the left and right inner masts. It is located on the rear side.

[0003]

In such a conventional mast device, the mast device is compared with a type in which a single free lift cylinder having a relatively large diameter is disposed between the left and right masts. Although there is nothing obstructing the view at the center, the operator's forward view from the driver's seat is improved, but it is driven by the free lift cylinder, especially when various attachments are added as a cargo handling device to the three-stage full free mast. Since a hydraulic hose for the above attachment will be attached besides the lift chain,
There is still room for improvement in further widening the field of view.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in particular, a lift chain wound around a wheel at the tip of a free lift cylinder and a hydraulic hose for various attachments are designed so as not to obstruct the view as much as possible. It is an object of the present invention to provide a mast device with a wider field of view.

[0005]

According to a first aspect of the present invention, there is provided a three-stage mast, which is formed as a full free mast, wherein each of a lift cylinder and a free lift cylinder is independent on the left and right. A free lift cylinder corresponding to the inner mast is arranged behind the inner mast, and a chain wheel for a lift chain mounted on a tip of a rod of each free lift cylinder is arranged obliquely.

According to a second aspect of the present invention, in a plan view of the left and right masts according to the first aspect of the present invention, the lift is located on a line connecting an anchor portion of the lift chain on the lift bracket side and an axis of the free lift cylinder. It features a chain wheel for the chain.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a hydraulic hose wheel attached to a tip of a rod of a free lift cylinder and around which a hydraulic hose for an attachment is wound is provided. It is characterized by being arranged diagonally with the chain wheel for the lift chain.

As is well known, in the three-stage full free mast, a lift chain for driving the lift bracket up and down with respect to the inner mast is wound around a chain wheel at the tip of the free lift cylinder, and one end of the lift chain is attached to the lift bracket. The other end is connected to a cylinder tube of an inner mast or a free lift cylinder, respectively.

At this time, as in the first aspect of the present invention,
By slanting the direction of the chain wheel attached to the rod end of the free lift cylinder, the part of the lift chain from the chain wheel to the chain anchor on the lift bracket side may be in the field of view for the operator. The portion of the lift chain from the chain wheel to the inner mast or the chain anchor on the cylinder tube side overlaps with the left and right masts and does not hinder the operator's view from the driver's seat.

And, as in the invention according to claim 2,
In a plan view of the left and right masts, if the chain wheel for the lift chain is arranged on the line connecting the anchor part on the lift bracket side of the lift chain and the axis of the free lift cylinder, the free lift cylinder and the chain wheel will be offset. As a result, a bending moment is not applied to the free lift cylinder, which is advantageous in strength, and also improves the durability of the seal portion.

That is, when the left and right free lift cylinders are arranged on the rear side of the inner mast and further outside so as to approach the lift cylinder, they overlap with the left and right masts, so that the operator's view is unlikely to be obstructed. On the other hand, as the free lift cylinder moves outward, the offset amount between the free lift cylinder and the chain wheel increases due to restrictions on the position of the chain anchor on the lift bracket side. For this reason, as in the second aspect of the invention, in plan view of the left and right masts, the lift chain is formed on a line connecting the anchor portion of the lift chain on the lift bracket side and the axis of the free lift cylinder. If the chain wheel is arranged, the free lift cylinder and the chain wheel are not offset, and a bending moment is not applied to the free lift cylinder, so that it is possible to achieve both an advantage in strength and a wide field of view.

In the three-stage full free mast, when various attachments are added to the lift bracket according to the cargo handling work, a hydraulic hose for supplying hydraulic pressure to the attachment is attached to the inner mast side, and the hydraulic hose is generally used. Then, it can be wound around a hydraulic hose wheel that is juxtaposed with the chain wheel at the tip of the free lift cylinder.

In such a case, if the wheel for the hydraulic hose around which the hydraulic hose for the attachment is wound is arranged obliquely together with the chain wheel for the lift chain as in the third aspect of the invention, The part of the hydraulic hose for the attachment from the hydraulic hose wheel to the outer mast side overlaps with the left and right masts along with a part of the lift chain, and that part, together with the lift chain, is substantially visible to the operator in front. Can be excluded from.

[0014]

According to the first aspect of the invention, the left and right independent free lift cylinders are arranged on the rear side of the corresponding inner mast, and the lift chains are mounted on the rod ends of the free lift cylinders. By arranging the chain wheel to be hung diagonally, a part of the lift chain wound around the chain wheel can be overlapped with the left and right masts and substantially eliminated from the operator's view, so that much There is an effect that a wider field of view for the operator can be secured.

According to the second aspect of the present invention, in a plan view of the left and right masts, the chain for the lift chain is located on a line connecting the anchor portion on the lift bracket side of the lift chain and the axis of the free lift cylinder. By arranging the wheels, the free lift cylinder and the chain wheel for the lift chain are not offset, and in addition to the same effect as the invention according to claim 1, the wide field of view and the free lift cylinder This has the effect of preventing bending load.

According to the third aspect of the present invention, the hydraulic hose wheel attached to the tip of the rod of the free lift cylinder and having the hydraulic hose for the attachment wound around it is slanted together with the chain wheel for the lift chain. As a result, the attachment hydraulic hose can be overlapped with the left and right masts as in the case of the lift chain, so that it can be virtually excluded from the operator's field of view. There is.

[0017]

1 to 7 show a preferred embodiment of the present invention, in which left and right outer masts 1 and corresponding left and right lift cylinders 2 are substantially integrated, Moreover, an example in which the lift cylinder 2 is a ram type cylinder type is shown. In addition, FIG.
FIG. 3 is a view corresponding to the plan view of FIG. 2, but shows only main components in order to avoid complication.

As shown in FIGS.
Middle mast 3 inside left and right outer mast 1
The inner mast 4 is arranged inside the middle mast 3 so as to be able to move up and down. The outer masts 1, 1 on the left and right are upper beams 5,
The right and left middle masts 3 are connected to each other via a cross beam 6 and a mast support 7, and also via an upper beam 9 and a lower beam (not shown).

On the other hand, the left and right inner masts 4 are mutually connected via a mast head 10 and a lower beam 11. A lift bracket 12 is provided inside each inner mast 4 so as to be able to move up and down, and a finger bar (carriage) 13 is attached to the lift bracket 12.
Various attachments (not shown) are attached to the finger bar 13 alone or together with a fork as a cargo handling device. Then, as shown in FIGS. 2, 4, and 5, the tip of a rod (ram or plunger) 14 of the lift cylinder 2 is connected to the upper beam 9 of the middle mast 3.

As shown in FIGS. 2, 4, and 5, the height of each mast is set higher by a predetermined amount in the middle mast 3 than in the outer mast 1, and the height of the inner mast 4 is higher than the middle mast 3. Is set higher by a predetermined amount a, and the wheel for the chain wheel 26 of the lift chain 28 for the inner mast and the wheel for the hydraulic hose 29 are set to be within the height difference a between the middle mast 3 and the inner mast 4 as described later. 27 are arranged.

As shown in FIG. 1, the left and right outer masts 1 are formed in a substantially U-shaped cross section by a web 1a and front and rear flange portions 1b.
An annular cylinder tube 15 which is a main element of the lift cylinder 2 is integrally formed in advance at an intermediate portion of a. On the other hand, the middle mast 3 disposed inside the left and right outer masts 1 is formed to have a substantially U-shaped cross section similarly to the outer mast 1, but a pair of front and rear ribs 3b project from the back side of the web 3a. The rib 3b is connected to the outer mast 1 via a liner 16 having an L-shaped cross section.
The middle mast 3 is guided so as to be able to move up and down with respect to the outer mast 1 by entering the inside of the side flange portion 1b. This slide guide structure is the same for the relationship between the middle mast 3 and the inner mast 4, and 17 is a liner.

With the above structure, the masts of the outer mast 1, the middle mast 3, and the inner mast 4 are completely overlapped in the front-rear dimension of the outer mast 1 without offsetting each other in the front-rear direction. Not only between the middle mast 3 and the inner mast 4 but also between the outer mast 1 and the cylinder tube 15 of the lift cylinder 2 integral therewith in the vehicle width direction, the cylinder tube 15 and the middle mast 3 The dimensions overlap each other in the vehicle width direction, and as a result, the outer mast 1,
The width of the left and right masts formed by the middle mast 3, the inner mast 4, and the lift cylinder 2 in the vehicle width direction is reduced.

Left and right free lift cylinders 18 of a ram type cylinder type or a single-acting piston type are erected on the lower beam 11 connecting the left and right inner masts 4, 4 so as to be located behind each inner mast 4. Have been. A chain wheel bracket 42 is attached to the tip of the rod of each free lift cylinder 18 in an oblique posture.
2 is equipped with two hydraulic hose wheels 43 and 44 in addition to the chain wheel 19.

A lift chain 20 is wound around each chain wheel 19, and one end of each lift chain 20 is connected to a chain anchor bracket 21 on the cylinder tube side of the free lift cylinder 18 via a chain anchor bolt. At the same time, the other end is connected to a chain anchor bracket 22 on the lift bracket 12 side via a chain anchor bolt 22a.

As is apparent from FIG. 1, in a plan view of the chain wheel 19, the chain wheel 19 is located on a line Q connecting the axis of the free lift cylinder 18 and the axis of the chain anchor bracket 22. Is set to

Also, wheels 43 and 4 for each hydraulic hose are provided.
4, hydraulic hoses 45 and 46 for supplying hydraulic pressure to actuators of various attachments (not shown) mounted on the lift bracket 12 as a cargo handling device are wound around the lift chain 20 in the same form. One end of each of the hydraulic hoses 45 and 46 is connected to the lift bracket 12.
Each of the hydraulic hoses 45 and 4 is connected to the actuator via a connector 47 (see FIG. 1) on the side.
The other end of 6 is connected to a control valve (not shown) via intermediate wheels 48 and 49 prepared separately.

Accordingly, when the free lift cylinder 18 having a large pressure receiving area extends from the state shown in FIG. 2, the lift bracket 12 alone rises along the inner mast 4 (free lift function). 2 is extended, the lift bracket 1 is moved along with the rising operation of the middle mast 3 and the inner mast 4.
2 will also rise integrally. Note that 23 in FIG.
Is a tilt bracket, and 24 is a mast support bracket.

A pair of left and right chain wheel brackets 25 are fixed to the upper beam 9 connecting the left and right middle masts 3, 3 in an oblique posture. A chain wheel 26 and a wheel 27 for a hydraulic hose are individually arranged side by side on these chain wheel brackets 25, and an inner mast lift chain 28 is provided on each chain wheel 26, and a wheel 2 for each hydraulic hose is provided.
A hydraulic hose 29 for supplying hydraulic pressure to the free lift cylinder 18 is wound around each of the cylinders 7. These chain wheels 26 and wheels 27 for hydraulic hoses, together with the chain wheel bracket 25,
The left and right masts, which are arranged so as to be within the height difference a between the middle mast 3 and the inner mast 4 and, at the same time, as shown in FIGS. Dimensionally overlap in both the front-rear direction and the vehicle width direction.

Then, the lift chain 2 for the inner mast
One end of 8 is connected to the upper beam 5 on the outer mast 1 side via a chain anchor bolt 30,
The other end of the inner mast lift chain 28 is a space 3 formed between the middle mast 3 and the inner mast 4.
1 (see FIG. 1) and is also connected to the lower end of the inner mast 4 via a chain anchor bolt 32. Similarly, one end of the hydraulic hose 29 is connected to the upper end of the lift cylinder 2 via a nipple 33 and communicates with the internal space of the cylinder 2.
The other end of 9 passes through a space 31 formed between the middle mast 3 and the inner mast 4 and is connected to the lower end of the inner mast 4 like the other end of the lift chain 28 for the inner mast.

More specifically, as shown in FIGS. 6 and 7 in addition to FIG. 2, a chain anchor bracket 34 is welded and fixed to the lower end of the inner mast 4, and the chain anchor bracket 34 is attached to the lift chain 2 for the inner mast.
8 is the chain anchor bolt 3 on the inner mast 4 side.
5 and a nut 36. An oil hole 37 is formed in the chain anchor bracket 34, and an end on the inner mast 4 side of the hydraulic hose 29 connected to the lift cylinder 2 is provided above the oil hole 37 via a nipple 38. On the other hand, an end of a hydraulic hose 39 for supplying hydraulic pressure to the free lift cylinder 18 is connected to a lower end of the oil hole 37 via a nipple 40.

With the above structure, a portion of the inner mast lift chain 28 and the hydraulic hose 29 from the chain wheel 26 to the chain anchor bracket 34 is not substantially exposed to the outside by passing through the space 31. As shown in FIG. 8, the lift cylinder 2 and the free lift cylinder 18 are always connected in series via the hydraulic hose 29, the oil hole 37, and the hydraulic hose 39.

Therefore, according to the present embodiment, when hydraulic pressure is supplied to the lift cylinder 2 via the control valve 41, the hydraulic oil in the lift cylinder 2 flows into the free lift cylinder 18 and firstly the pressure receiving area is reduced. As a result, the large free lift cylinder 18 is extended and the chain wheel 19 and the hydraulic hose wheels 43 and 44 at the tip of the free lift cylinder 18 are pushed up.
As a basic function of the full free mast, the lift bracket 12 moves up alone via the lift chain 20 until the lift bracket 12 reaches the upper end of the inner mast 4.

When the lift bracket 12 reaches the upper end of the inner mast 4, that is, when the free lift cylinder 18 is in the maximum extension state, the lift cylinder 2 starts to extend for the first time from this point of time, and the lift operation of the middle mast 3 is started. Inner mast 4 is lift bracket 12
The lift is lifted via a chain wheel 26 and an inner mast lift chain 28. That is, the inner mast 4 moves up at a speed and a stroke twice as fast as the middle mast 4 in accordance with the rising operation of the middle mast 3.

At this time, as is apparent from FIGS. 1 and 3, the chain wheel 19 at the tip of the rod of each free lift cylinder 18 and the wheels 43 and 44 for hydraulic hoses are in an oblique posture.
Lift chain 2 wound around 9, 43, 44
0 and the hydraulic hoses 45 and 46 at least on the rear side of the free lift cylinder 18 overlap with the left and right masts together with the free lift cylinder 18 when viewed from the driver's seat. It does not hinder forward vision.

As described above, the portion from the chain wheel 26 to the chain anchor bracket 34 of the inner mast lift chain 28 and the hydraulic hose 29 is a space 31 between the middle mast 3 and the inner mast 4.
The rear side of the left and right masts are clean and the visibility is improved because they are housed and hidden at the same time. Also, it is possible to realize a wide field of view of the operator.

Here, in the present embodiment, the type in which the outer mast 1 and the lift cylinder 2 are substantially integrated is exemplified, but the present invention separates the left and right outer masts and the corresponding lift cylinders from each other. The present invention can also be applied to a type having a body structure.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention and is an enlarged view of a main part of FIG. 3;

FIG. 2 is a perspective view of the entire mast device showing the embodiment of the present invention.

FIG. 3 is an explanatory plan view of the mast device shown in FIG. 2;

FIG. 4 is a view in the direction of arrow A in FIG. 2;

FIG. 5 is a view in the direction of arrow B in FIG. 2;

FIG. 6 is an enlarged view of a portion C in FIG. 2;

FIG. 7 is a further enlarged explanatory view of FIG. 6;

FIG. 8 is a schematic explanatory diagram of a hydraulic system in the mast device of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer mast 2 ... Lift cylinder 3 ... Middle mast 4 ... Inner mast 12 ... Lift bracket 18 ... Free lift cylinder 19 ... Chain wheel 22 ... Chain anchor bracket 22a ... Chain anchor bolt 20 ... Lift chain 43, 44 ... Hydraulic hose wheel 45 , 46… Hydraulic hose

Claims (3)

[Claims] 1. A free lift cylinder formed as a full free mast, wherein a lift cylinder and a free lift cylinder are left and right independent three-stage masts, and a rear lift cylinder corresponding to the inner mast is provided at a rear side of each inner mast. And a chain wheel for a lift chain mounted on a tip of a rod of each free lift cylinder is disposed obliquely. 2. A chain wheel for a lift chain is arranged on a line connecting an anchor portion on a lift bracket side of a lift chain and an axis of a free lift cylinder in plan view of the left and right masts. 2. A mast device for a forklift truck according to claim 1. 3. A hydraulic hose wheel mounted on a tip of a rod of a free lift cylinder and wound with a hydraulic hose for an attachment is arranged obliquely together with a chain wheel for a lift chain. 3. A mast device for a forklift truck according to 1 or 2.