JP3348638B2 - Mast device for forklift truck - Google Patents

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 three-stage type in which a lift cylinder and a free lift cylinder are formed as a free mast and a slide mast, and each of a lift cylinder and a free lift cylinder is independent on the left and right. Regarding the structure of the mast.

[0002]

2. Description of the Related Art In a three-stage mast configured as a full free mast and a slide mast, as is well known, a lift bracket supported on an inner mast is moved up and down by a free lift cylinder also provided on the inner mast. After the lift bracket reaches the maximum position with respect to the inner mast, the middle mast is raised by the lift cylinder on the outer mast side, and the inner mast is doubled through the inner mast lift chain according to the lift displacement of the middle mast. (See, for example, Japanese Utility Model Laid-Open No. 59-123096).

[0003]

In such a conventional mast device, one end of the inner mast lift chain is connected to the upper end of the outer mast, and the other end of the inner mast lift chain is connected to the lower end of the inner mast. The inner mast is lifted up by pushing up the middle part of the lift chain for the inner mast with a chain wheel provided on the middle mast, but in order to widen the field of view, a space formed between the middle mast and the inner mast is lifted. When trying to accommodate a part of the inner mast lift chain in this space by using it effectively,
The processing of the chain anchor becomes a problem.

In other words, if the inner mast lift chain is to be accommodated in the above space, the inner mast side chain anchor must necessarily be installed in a closed space between the inner mast and the outer mast. The work of attaching and detaching the chain becomes troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a three-stage mast configured as a full free mast and a slide mast, a space between a middle mast and an inner mast is effectively used. An object of the present invention is to provide a mast device in which, when a lift chain for an inner mast is accommodated in a leverage space, the workability of attaching and detaching the chain at the chain anchor portion is improved.

[0006] The invention described in claim 1, while being formed as and slide mast full free mast, with each of the lift cylinders and the free lift cylinder is independent in right and left, the lift cylinder ram type
About three-stage mast of the type formed by the cylinder, the space formed between the inner mast and the middle masts, oil, one end of which is connected to the upper end of the lift cylinder
The pressure hose accommodated with chains for the inner mast drive, the lower end of the inner mast side of the chain, as well as connecting to a chain anchor bracket which is detachably attached to the lower end face of the inner mast, the chain anchor bracket to form oil holes , The hydraulic hoe on the lift cylinder side
Other than the hydraulic hose connected to the other end of the
And the chain anchor bracket in which the oil hole is formed.
Are connected to each other as connectors .

[0007]

According to a second aspect of the present invention, the left and right outer masts according to the first aspect of the invention and the corresponding cylinder tube of the lift cylinder are formed as a single unit in advance.

[0009] The invention described in claim 3 is the invention according to claim 1 or
A pair of left and right free lift cylinders according to the invention described in Item 2 is arranged behind the corresponding left and right masts.

Therefore, according to the first aspect of the present invention,
The lift chain for the inner mast is wound around the chain wheel provided at the upper end of the middle mast,
One end of the chain is connected to the inner mast, and the other end is connected to the outer mast.However, by attaching a detachable chain anchor bracket to the lower end of the inner mast, the part of the chain from the chain wheel to the chain anchor bracket is , Are housed in the space formed between the inner mast and the middle mast and are not exposed to the outside. Since the chain anchor bracket is detachable at the lower end of the inner mast, if the chain anchor bracket is removed, the joint between the chain anchor bracket and the chain will come out. The attachment and detachment of the bracket and the chain can be easily performed.

In addition, a part of the hydraulic hose having substantially the same form as the above-mentioned chain winding structure is housed together with the chain in the space formed between the inner mast and the middle mast and is not exposed to the outside. . At the same time, because the lift cylinder, which is a ram-type cylinder, and the free lift cylinder with a large pressure receiving area are connected in series, when hydraulic pressure is supplied to the lift cylinder, the free lift cylinder is first extended to the maximum, The sequential operation peculiar to the full-free three-stage mast in which the lift cylinder is extended can be performed. The chain anchor bracket not only functions as a chain anchor bracket, but also substantially serves as a connector for connecting a hydraulic hose. Through this connector, the hydraulic hose on the lift cylinder side and the hydraulic hose on the free lift cylinder side are connected. Is connected, so that the chain anchor bracket and the hydraulic hose can be easily attached and detached.

According to the second aspect of the present invention, since the left and right independent lift cylinders and the corresponding outer mast are formed substantially integrally, the outer mast including the lift cylinder is dimensioned in the vehicle width direction. Consequently, the dimensions of the left and right masts in the vehicle width direction are reduced.

According to the third aspect of the present invention, the left and right independent free lift cylinders and the corresponding left and right masts overlap in the vehicle width direction,
The size of the left and right masts including the free lift cylinder in the vehicle width direction is reduced.

[0014]

According to the first aspect of the present invention, a part of the inner mast lift chain is accommodated in the space formed between the inner mast and the middle mast and is not exposed to the outside. In addition to ensuring a wider field of view for the operator in front, the view can be made clearer by hiding it from the field of view.In addition, the lower end of the inner mast side of the chain is attached to the removable chain anchor bracket at the lower end of the inner mast Because it is connected, by removing the chain anchor bracket, the joint part of the chain and the chain anchor bracket comes out, and at the time of maintenance inspection or repair, etc., without moving the inner mast and the middle mast relatively each time, Easy attachment and detachment of the chain and chain anchor bracket, There is an effect that can improve the workability of these tasks.

In addition, since the chain anchor bracket receives the load in the vertical direction by the chain at the lower end surface of the inner mast, there is an effect that the mounting structure of the chain anchor bracket to the inner mast can be simplified.

Further, a part of the hydraulic hose for connecting the lift cylinder, which is a ram-type cylinder, to the free lift cylinder is also accommodated in the space between the inner mast and the middle mast together with the inner mast drive chain and is not exposed to the outside. Therefore, the effect of widening the field of view in the front and the effect of clearing the field of view become even more remarkable.In addition, the above-mentioned chain anchor bracket also has a function as a connector for connecting hydraulic hoses, making it extremely easy to attach and detach hydraulic hoses. There is an effect that can be done.

According to the second aspect of the present invention, since the left and right outer masts and the corresponding ram-type cylinder type lift cylinders are substantially integrated, the vehicle width of the left and right masts including the lift cylinders is provided. The size in the direction can be reduced, and in addition to the effect similar to that of the first aspect of the invention, there is an effect that a wider field of view can be realized.

According to the third aspect of the present invention, the left and right independent free lift cylinders are arranged behind the corresponding left and right masts, so that the same effect as the first or second aspect of the present invention is obtained. In addition, the size of each of the left and right masts in the vehicle width direction can be reduced, which also has the effect of contributing to widening the front view.

[0019]

1 to 8 show a preferred embodiment of the present invention. In particular, as shown in FIG. 4, the left and right outer masts 1 and the corresponding left and right lift cylinders 2 are substantially formed. And the lift cylinder 2 is a ram-type cylinder type. FIG. 5 is a view corresponding to the plan view of FIG. 4, but shows only main components in order to avoid complication.

As shown in FIGS. 4 to 7, the lift cylinder 1
Middle mast 3 inside left and right outer masts 2
The inner mast 4 is arranged inside the middle mast 3 so as to be able to move up and down. The left and right outer masts 2, 2 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.
Is fixed, and a fork (not shown) is attached to the finger bar 13. The tip of a rod (ram or plunger) 14 of the lift cylinder 2 is connected to the middle mast 3.

As shown in FIGS. 4 to 7, 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 inner mast 4 is set higher than the inner mast 4 by a predetermined amount a, and the chain wheel 26 and the hydraulic pressure of the inner mast lift chain 28 are adjusted so as to be within the height difference a between the middle mast 3 and the inner mast 4 as described later. A wheel 27 for a hose 29 is arranged.

As shown in FIG. 5, 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.

According to the above structure, the outer mast 1, the middle mast 3, and the inner mast 4 are completely overlapped in the front-rear direction 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 on the rear side of each inner mast 4. A chain wheel 19 is attached to the tip of the rod of each free lift cylinder 18. 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. The end is connected to the chain anchor bracket 22 on the lift bracket 12 side.

Accordingly, when the free lift cylinder 18 is extended from the state shown in FIG. 4, the lift bracket 12 is independently raised along the inner mast 4 (free lift function), and the lift cylinder 2 is extended as described later. Then, the lift bracket 12 is also moved up integrally with the movement of the middle mast 3 and the inner mast 4. In FIG. 4, reference numeral 23 denotes a tilt bracket, and 24 denotes 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 and 3 to each other. A chain wheel 26 and a wheel 27 for a hydraulic hose are individually arranged side by side on these chain wheel brackets 25, a lift chain 28 for an inner mast is mounted on each chain wheel 26, and a hydraulic hose 29 are wound around each. The chain wheel 26 and the hydraulic hose wheel 27, together with the chain wheel bracket 25,
The inner mast 4 and the inner mast 4 are arranged so as to be within the height difference a, and at the same time, as is apparent from FIGS. 5 to 7, the front and rear masts formed by the outer mast 1, the middle mast 3 and the inner mast 4 Dimensionally overlap both in the 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. 5), 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 3 like the other end of the lift chain 28 for the inner mast.

More specifically, as shown in FIGS. 4 to 3 in addition to FIG. 4, a plurality of mounting bolts 34 are previously fixed to the lower end surface of the inner mast 4 by welding. A plate-shaped chain anchor bracket 36 is detachably mounted via the plate. A chain anchor pin 37 is fixed to the chain anchor bracket 36 in advance by welding, and an end of the inner mast lift chain 28 on the inner mast 4 side is connected to the chain anchor pin 37.

The chain anchor bracket 36 has an oil hole 38 having one end opened on the upper surface and the other end opened on the side surface, and the upper surface of the chain anchor bracket 36 communicates with one end of the oil hole 38. Nipple 39
Is fixed to the nipple 39, and the end on the inner mast 4 side of the hydraulic hose 29 connected to the upper end of the lift cylinder 2 is detachably connected to the nipple 39.
Further, a free lift cylinder 1 is provided at the other end of the oil hole 38.
The end of a hydraulic hose 40 connected to the lower end of 8 is detachably connected via a nipple 41. Thus, since the chain anchor bracket 36 has the oil hole 38, it also has a function as a connector for connecting the hydraulic hoses 29 and 40.

Due to the above-mentioned structure, of the inner mast lift chain 28 and the hydraulic hose 29 on the lift cylinder 2 side, a portion from the chain wheel 26 and the hydraulic hose wheel 27 to the chain anchor bracket 36 forms the space 31. The lift cylinder 2 and the free lift cylinder 18 are connected to the hydraulic hose 29 on the lift cylinder 2 side, the hydraulic hose 40 on the free lift cylinder 18 side, and both. As shown in FIG. 8, they are always connected in series via a chain anchor bracket 36 interposed as a connector between the hoses 29 and 40.

Therefore, according to the present embodiment, when hydraulic pressure is supplied to the lift cylinder 2 via the control valve 42, the hydraulic oil in the lift cylinder 2 flows into the free lift cylinder 18 and firstly the pressure receiving area is reduced. The large free lift cylinder 18 is extended, and as a basic function of the full free mast, the lift bracket 12 moves up alone until the lift bracket 12 reaches the upper end of the inner mast 4. Then, 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, and the middle mast 3
The inner mast 4 is lifted together with the lift bracket 12 via the chain wheel 26 and the inner mast lift chain 28 in accordance with the ascent operation. That is,
As the middle mast 3 moves up, the inner mast 4 moves up at a speed and a stroke twice that of the middle mast 3.

As described above, the portion from the chain wheel 26 to the chain anchor bracket 36 of the inner mast lift chain 28 and the hydraulic hose 29 is the space 3 between the middle mast 3 and the inner mast 4.
1, the rear surfaces of the left and right masts are neat and the view is improved, and at the same time, the portions do not obstruct the view of the operator. The synergistic effect with the reduction of the width dimension of each mast can realize a wide field of view for the operator.

In addition, the mast height of the inner mast 4 is set to be higher than the middle mast 3 by a predetermined amount a, and the chain wheel 26 for lifting the inner mast provided at the upper end of the middle mast 3 is set to the predetermined size. a so that the free lift stroke can be secured larger, and even if the chain wheel 26 protrudes above the middle mast 3, it does not exceed the height of the inner mast 4. In particular, the height of the inner mast 4 can sufficiently protect the chain wheel 26 and the hydraulic hose wheel 27 from collision with other structures and the like, especially during traveling of a forklift truck. Become.

As shown in FIGS. 1 to 3, the chain anchor bracket 36 on the inner mast 4 side is detachable at the lower end surface of the inner mast 4, and is formed between the inner mast 4 and the middle mast 3. The inner mast lift chain 28 which passes through the space 31 from its upper end to the lower end is connected to the chain anchor pin 37 on the chain anchor bracket 36 side, and the oil hole 38 is also provided for the hydraulic hose 29 which has also passed through the space 31. Since the formed chain anchor bracket 36 is connected as a connector to the hydraulic hose 40 on the side of the free lift cylinder 18, the chain does not need to be relatively moved between the inner mast 4 and the middle mast 3 for maintenance, inspection and repair. Insert anchor bracket 36 into inner mast 4
From the chain anchor bracket 36, the inner mast lift chain 28 and the hydraulic hose 2
The joints with the joint 9 are exposed to the outside, and the detachment at each joint can be easily performed.

Moreover, the lift chain 2 for the inner mast
8, the chain anchor bracket 36 on the lower end surface of the inner mast 4 receives the vertical force and finally the inner mast 4 bears the force in the longitudinal direction. The mounting structure can also be simplified.

[0037]

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of the present invention, and is an exploded perspective view of a lower end portion of an inner mast.

FIG. 2 is an enlarged explanatory view of the chain anchor bracket shown in FIG. 1;

FIG. 3 is an explanatory plan view of the chain anchor bracket shown in FIG. 2;

FIG. 4 is a perspective view of the entire mast device showing the first embodiment of the present invention.

FIG. 5 is an explanatory plan view of FIG. 4;

FIG. 6 is an explanatory front view of a main part of the mast device of FIG. 4 as viewed from the driver's seat side.

FIG. 7 is an explanatory left side view of the mast device in FIG. 6;

FIG. 8 is an explanatory diagram of a hydraulic system of a lift cylinder and a free lift cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer mast 2 ... Lift cylinder 3 ... Middle mast 15 ... Cylinder tube 18 ... Free lift cylinder 26 ... Chain wheel 28 ... Inner mast lift chain 29 ... Hydraulic hose 31 ... Space part 36 ... Chain anchor bracket 38 ... Oil hole 40 ... Hydraulic hose

Claims (3)

(57) [Claims] It is assumed that the lift cylinder and the free lift cylinder are independent on the left and right while being formed as a full free mast and a slide mast.
In particular, the lift cylinder is formed by a ram cylinder
The A-type three-stage mast, the space formed between the inner mast and the middle masts, a hydraulic ho having one end connected to the upper end of the lift cylinder
The over scan accommodated with chains for the inner mast drive, the lower end of the inner mast side of the chain, as well as connecting to a chain anchor bracket which is detachably attached to the lower end face of the inner mast, the chain anchor bracket to form oil holes And the other end of the hydraulic hose on the lift cylinder side
The other end of the hydraulic hose connected to the
Use the formed chain anchor bracket as a connector
A mast device for a forklift truck, which is connected to each other . 2. The left and right outer masts and the corresponding outer masts.
The cylinder tube of the lift cylinder is
The mast device for a forklift truck according to claim 1, wherein the mast device is formed as follows . 3. A pair of left and right free lift cylinders is supported.
It is characterized by being arranged behind the left and right masts
A mast device for a forklift truck according to claim 1 or 2 .