JPH10152300A - Forklift truck mast device - Google Patents

Abstract

(57) [Problem] To simply improve the visibility of a free-lift cylinder at the center of a mast device by simply integrating an outer mast and a cylinder tube of a lift cylinder. SOLUTION: The web 22 and a cylinder tube 24 of a lift cylinder 1 are integrally formed in advance so as to be located in the middle of the web 22 of the outer mast 2 while overlapping each other in the vehicle width direction. The inner mast 3 is guided and supported by the outer mast 2 via the liner 29 so as to overlap the cylinder tube 24 in the vehicle width direction.
The size W in the vehicle width direction is reduced. The free lift cylinders 14 are arranged independently on the left and right sides of the inner mast 3 independently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full free mast type mast device for a forklift truck, and more particularly to a mast device for an operator by changing a relative positional relationship among an outer mast, an inner mast, a lift cylinder and a free lift cylinder. The present invention relates to a mast device capable of securing a wider front view.

[0002]

2. Description of the Related Art Japanese Unexamined Utility Model Publication No. Sho 59-123096 and Japanese Utility Model Laid-Open Publication No. Sho 62-1 are so-called wide-view masts having improved forward visibility for an operator.
There is one described in JP-A-32099. In these conventional mast devices, for example, as shown in FIG. 6, a pair of left and right lift cylinders 51 for raising and lowering the inner mast is arranged behind the left and right outer masts 52, and the finger bar (carriage) 53 is also independently raised and lowered. A pair of left and right free lift cylinders 54 are arranged behind the left and right inner masts 55.

[0003] In such a conventional mast device, compared with a type in which a single free-lift cylinder having a relatively large diameter is disposed in the middle of the left and right masts, a device that hinders the view at the center of the mast device. Although the front view of the operator from the driver's seat is improved due to the elimination, the reduction of the width dimension W of the mast itself in the vehicle width direction is naturally limited, leaving room for further improvement of the front view.

On the other hand, for the purpose of reducing the number of components and weight of the mast device, for example, Japanese Patent Application Laid-Open No. 57-1756.
As described in JP-A-99-99, an outer mast 52 as shown in FIG. 6 and a cylinder tube of a lift cylinder 51 are integrally formed, but in this type, an outer mast is provided on an outer surface of the outer mast. The hollow cylinder tube-equivalent portion is merely integrated in advance so as to be circumscribed, and there is a problem that the width W cannot be reduced.

The present invention has been made in view of the above-mentioned problems, and is based on a premise that a structure in which an outer mast and a cylinder tube of a lift cylinder are previously formed integrally is provided.
It is an object of the present invention to provide a structure capable of further reducing the width dimension (dimension in the vehicle width direction) of each of the left and right masts.

[0006]

According to the first aspect of the present invention, the left and right outer masts are arranged such that the left and right outer masts and the corresponding left and right independent lift cylinders overlap each other in the vehicle width direction. And the corresponding cylinder tubes of the lift cylinder are integrally formed, and the cylinder tubes and the left and right inner masts are arranged via the inner mast liner with respect to the outer masts so as to overlap each other in the vehicle width direction. The left and right free lift cylinders for raising and lowering the finger bar independently are arranged at the rear side of the left and right masts.

According to a second aspect of the present invention, the inner mast in the first aspect of the invention is a middle mast, and the inner mast is guided and supported by the middle mast, so that the entire mast is a three-stage mast. It is characterized by being formed.

According to a third aspect of the present invention, the outer mast according to the first or second aspect has a slide guide surface in front and behind the cylinder tube of the lift cylinder. The inner mast is guided and supported by the slide guide surface.

According to a fourth aspect of the present invention, the outer mast and the inner mast according to the first or the second aspect of the present invention are not offset from each other in the front-rear direction but within the front-rear dimension of the outer mast. Are polymerized.

Therefore, according to the first and second aspects of the present invention, the outer mast, the cylinder tube of the lift cylinder integrated with the outer mast, and the inner mast overlap each other in the vehicle width direction. The size of each mast in the vehicle width direction is reduced.

In addition, since the free lift cylinders are independent on the left and right and are disposed behind the left and right masts, the free lift cylinders do not obstruct the view at the center of the mast device. Due to the synergistic effect with the reduction of the size of the mast in the vehicle width direction, it is possible to further secure the operator's front view.

Then, as in the invention according to claim 3,
Since the inner mast is guided by two slide guide surfaces set before and after the outer mast with the cylinder tube interposed therebetween, the inner mast can be smoothly moved up and down with respect to the outer mast.

Further, as in the invention according to claim 4,
Since the outer mast and the inner mast overlap within the front-rear dimension of the outer mast, the front-rear dimension of the mast device is also reduced along with the reduction of the vehicle width-direction dimension.

[0014]

According to the first and second aspects of the present invention, the left and right outer masts, the inner mast, and the lift cylinder overlap each other in the vehicle width direction, and the free lift cylinders are The rear side of the mast allows the left and right masts to be greatly reduced in size in the vehicle width direction, and there is no obstruction at the center of the left and right masts. Only the area that hinders the forward view of the operator is reduced, so that the forward view of the operator can be more widely secured, and there is an effect that the workability of the cargo handling work can be improved.

According to the third aspect of the present invention, the inner mast is guided by the slide guide surface set before and after the cylinder tube of the lift cylinder among the outer masts. In addition to the same effect as the invention described in (1), there is an effect that the raising / lowering operation of the inner mast is performed more smoothly.

According to the fourth aspect of the present invention, since the outer mast and the inner mast are overlapped within the front-rear dimension of the outer mast without being offset in the front-rear direction. In addition to the same effect as the invention described in claim 1 or 2, the effect that the front overhang, which is the dimension from the front axle to the finger bar, can be reduced by reducing the front-rear dimension of the left and right masts. is there.

[0017]

1 and 2 are views showing a typical embodiment of the present invention, showing an example of a two-stage mast.

As shown in FIGS. 1 and 2, the lift cylinder 1
Inner mast 3 inside the left and right outer masts 2
Are arranged so as to be able to move up and down. Left and right outer mast 2,
The two inner masts 3 are mutually connected via an upper beam 4, a cross beam 5 and a mast support 6, while the left and right inner masts 3 are mutually connected via a mast head 7, a tie beam 8 and a lower beam 9. I have. A lift bracket 10 is disposed inside each inner mast 3 so as to be able to move up and down, and a finger bar (carriage) 11 is attached to the lift bracket 10.
Is fixed, and a fork (not shown) is attached to the finger bar 11. As shown in FIG. 2, the piston rod 12 of the lift cylinder 1 is connected to the inner mast 3 via a bracket 13.

Left and right free lift cylinders 14 are erected on the lower beam 9 so as to be located behind each inner mast 3. A chain wheel is attached to the tip of a piston rod 15 of each free lift cylinder 14. 16 are mounted. A lift chain 17 is wound around each chain wheel 16, one end of each lift chain 17 is connected to a chain anchor bracket 19 on the cylinder tube 18 side of the free lift cylinder 14, and the other end is connected to the lift bracket 10.
Side chain anchor bracket 10a.

Therefore, when the free lift cylinder 14 extends from the state shown in FIG. 2, the finger bar 11 rises alone along the inner mast 3 (free lift function), and when the lift cylinder 1 further extends, the inner mast 3 As a result, the finger bar 11 also rises integrally. In FIG. 2, reference numeral 20 denotes a tilt bracket, and reference numeral 21 denotes a mast support bracket.

The left and right outer masts 2 described above are used in FIG.
As shown in FIG. 2, although the web 22 and the flange 23 formed to be bent before and after the web 22 are formed in a substantially U-shaped cross section, a circle which is a main element of the lift cylinder 1 is provided at an intermediate portion of the web 22. An annular cylinder tube 24 is integrally formed in advance.

On the other hand, the left and right inner masts 3 disposed inside the left and right outer masts 2 are formed in a substantially U-shaped cross section by the web 25 and the front and rear flange portions 26, but the web 25 A pair of front and rear ribs 27 are formed on the rear side so as to protrude. When the ribs 27 enter the inside of the flange portion 23 on the outer mast 2 side, the inner mast 3 is guided to be movable up and down with respect to the outer mast 2.

That is, the outer mast 2 and the cylinder tube 24 integral therewith have dimensions overlapping each other in the vehicle width direction, and at the same time, the cylinder tube 24 and the inner mast 3 also have dimensions mutually overlapping in the vehicle width direction. Since the outer mast 2 and the lift cylinder 1 and the inner mast 3 partially overlap each other in the vehicle width direction as a result, the width dimension W of the left and right masts is reduced.

The outer corners of the flange portion 19 before and after the outer mast 2 are set as an outer angled slide guide surface 28 for the inner mast 3, and the outer angled liner 29 is also attached to the slide guide surface 28. The inner mast 3 is guided so as to be able to move up and down, and the position of the inner mast 3 with respect to the outer mast 2 in the vehicle width direction and the vehicle front-rear direction is regulated. As a result, the outer mast 2 and the inner mast 3 are completely overlapped within the front-rear dimension of the outer mast 2 without offsetting each other in the front-rear direction.

Therefore, according to the present embodiment, in addition to the fact that the free lift cylinder 14 does not exist at the center of the mast device, as shown in FIG. As a result, the area obstructing the operator's view when viewed from the driver's seat can be made as small as possible, whereby the operator's forward view can be secured more widely, and cargo handling work can be ensured. Workability and safety at the time can be improved.

In addition, the outer mast 2 and the inner mast 3
Are overlapped within the front-rear direction dimensions of the outer mast 2, and each of the inner masts 3 is made independent of a free lift cylinder which is conventionally disposed as a single unit in the central part of the mast device. Since it is arranged on the rear side, the diameter of each free lift cylinder 14 is reduced, so that the front overhang at the distance from the front axle to the finger bar 11 can also be reduced.

FIG. 3 is a view showing a second embodiment of the present invention. FIG. 1 shows that an outer mast 32 and a cylinder tube 33 of a lift cylinder 31 are previously formed integrally.
Outer mast 32, although common to that shown in
The flange portion 35 is integrally formed only on the front side of the web 34, while the cylinder tube 33 of the lift cylinder 31 is integrally formed on the rear side of the web 34, so that the web 34, the flange portion 35 and the cylinder tube 3 are formed.
3 form a substantially U-shaped guide support surface 36.

On the other hand, on the back side of the web 38 of the inner mast 37, a prismatic thick rib 39 is integrally formed, and this rib 39 is guided to the guide support surface 36 of the outer mast 32 via an inner angled liner 40. It is supported.

In the case of this embodiment, it functions in exactly the same way as in the first embodiment.

FIG. 4 is a view showing a third embodiment of the present invention, and shows an example of a three-stage mast. In this embodiment, as apparent from comparison with FIG.
This is different from the first embodiment in that a middle mast 41 having the same shape as the inner mast 3 is interposed between the inner mast 3 and the inner mast 3.

FIG. 5 is a view showing a fourth embodiment of the present invention, and shows an example of a three-stage mast similarly to FIG. In this embodiment, as is apparent from comparison with FIG.
A middle mast 42 having the same shape as the inner mast 37 is guided and supported by the outer mast 32, and an inner mast 44 having a pair of ribs 43 on the back surface is guided and supported by the middle mast 42 via a liner 45.

Needless to say, the third and fourth embodiments also provide the same functions as those of the first and second embodiments.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and FIG.
The enlarged sectional view which follows the A line.

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

FIG. 3 is an essential part cross-sectional view of a mast device showing a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a mast device according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a mast device showing a fourth embodiment of the present invention.

FIG. 6 is an explanatory plan view showing an example of a conventional mast device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lift cylinder 2 ... Outer mast 3 ... Inner mast 11 ... Finger bar 14 ... Free lift cylinder 22 ... Web 24 ... Cylinder tube 28 ... Slide guide surface 29 ... Liner 31 ... Lift cylinder 32 ... Outer mast 33 ... Cylinder tube 37 ... Inner mast 40 ... Liner 41 ... Middle mast 42 ... Middle mast 45 ... Liner

Claims (4)

[Claims] 1. The left and right outer masts and the corresponding lift cylinder cylinder tubes are integrated so that the left and right outer masts and the corresponding left and right independent lift cylinders overlap each other in the vehicle width direction. And each of the cylinder tubes and the left and right inner masts are slidably guided and supported via the inner mast liner with respect to the outer mast so as to overlap each other in the vehicle width direction. A mast device for a forklift truck, characterized in that left and right free lift cylinders for raising and lowering by means of a mast are arranged behind the left and right masts. 2. The mast according to claim 1, wherein the inner mast is a middle mast, and the inner mast is guided and supported by the middle mast, so that the entire mast is formed as a three-stage mast. Mast device for forklift trucks. 3. The outer mast has a slide guide surface in front of and behind the cylinder tube of the lift cylinder, and the inner mast is guided and supported by the two front and rear slide guide surfaces. The mast device for a forklift truck according to claim 1 or 2, wherein 4. The outer mast and the inner mast are overlapped with each other within the longitudinal dimension of the outer mast without offsetting the outer mast and the inner mast in the longitudinal direction. A mast device for a forklift truck according to the above.