JPH0450317Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) This invention is a three-stage mast type forklift that has an outer mast, a middle mast, and an inner mast, and the oil control valve on the machine base and various attachments on the lift bracket. This relates to the hydraulic piping inside the mast that connects the

(Prior Art) Fig. 4 shows a conventional example of a three-stage mast type forklift, in which 1 is a left and right outer mast erected on the machine platform, and 2 is a column supported on the inside of this outer mast 1 so as to be movable up and down. 4 is a left and right inner mast supported so as to be movable up and down on the inside of the middle mast 2; 6 is a lift bracket that is supported so as to be movable up and down on the inside of this inner mast 4; 11 is the outer mast. Left and right rear lift cylinders 12 are provided upright on the rear side of the middle mast 2 and have a piston rod 11a connected to the upper part of the middle mast 2; left and right chain wheels 12 are provided on the rear side of the middle mast 2; 13
14 is a left and right chain that is wound around the chain wheel 12 and has one end attached to the upper part of the outer mast 1 and the other end attached to the lower part of the inner mast 4, and 14 stands on this chain at the center between the left and right inner masts 4. A front cylinder 16 is provided with a piston rod 14 of this front cylinder 14.
Both left and right chain wheels provided on a, 17
is a chain that is wound around this chain wheel 16 and has one end attached to the middle part of the inner mast 4 and the other end attached to the lift bracket 6.

Regarding the hydraulic piping inside the mast, a pulley 19 is supported on the piston rod 14a on the outside of both left and right chain wheels 16 on the front cylinder 14, and a pair of pulleys is supported on the inside of the chain wheel 12 behind one of the inner masts 4. 20
is supported at the top of the middle mast 2. Two mast pipes (not shown) are fixed to the middle part of the outer mast 1, and the inner mast 4
2 each in the middle part and lift bracket 6.
Two connector pipes 22, 23 are fixed. There are two hoses (not shown) between the oil control valve (not shown) attached to the machine base (not shown) and the mast pipe (not shown).
is connected, and two hoses 26 wound around the pulley 20 of the middle mast 2 are connected between this mast pipe and the connector pipe 22 of the inner mast 4. Two hoses 27, which are wound around a pulley 19 on the front cylinder 14, are connected between the bracket 6 and the connector pipe 23.

(Problem to be solved by the invention) However, in the mast hydraulic piping structure described above, both hoses correspond to each other in a front-back positional relationship and constitute the same piping route together with both connector pipes 22 and 23 and the mast pipe. 26 and 27 are wound around the pulleys 19 and 20 with their positions shifted in the left and right direction, so when one pulley 19 is raised and viewed from the driver's seat, there is a gap between the left and right inner masts 4 and 4 inside the mast. Despite having a double piping structure, there was a problem in that the four hoses obstructed the view in front of the forklift, impairing the workability of the forklift.

This idea was devised in view of the above problem, and its purpose is to connect both the left and right sides of the hydraulic piping inside the mast by means of a series of hoses wrapped around the pulley on the piston rod and the pulley on the middle mast. To provide an in-mast hydraulic piping structure for a three-tier mast type forklift, which can minimize the obstructed area between the inner masts, improve the field of view in front of the forklift, and improve the workability of the forklift. .

Structure of the invention (means for solving problems) In order to achieve the above object, this invention connects the left and right middle masts movably up and down to the left and right outer masts installed on the machine base, and also connects the left and right middle masts vertically. Both the left and right inner masts are operatively connected to the mast so that they can move up and down, and a cylinder with a piston rod that is driven up and down is installed on the inner mast, and a lift bracket that is moved based on the drive of the cylinder can be moved up and down. Hydraulic piping is installed between the left and right inner masts, and connects various attachments on the lift bracket to an oil control valve installed on the driver's seat side of the machine base, and the hose of the hydraulic piping is wrapped around it. In a three-stage mast type forklift, in which pulleys are provided on the piston rod of the cylinder and on the middle mast, respectively, among the hydraulic piping, the oil control valve side opening of the connector pipe attached to the lift bracket and the pulley attached to the inner mast are provided. each opening on the lift bracket side and oil control valve side of the connector pipe attached to the outer mast, the lift bracket side opening of the mast pipe attached to the outer mast, the pulley provided on the piston rod and the pulley provided on the middle mast, The gist is that the hoses are arranged approximately on the same line in the front-rear direction when viewed from above, and are wound around each of the pulleys to connect the corresponding openings of the pipes. .

(Function) That is, when the pulley moves up and down with the up-and-down movement of the piston rod or the up-and-down movement of the middle mast, the hose wound around the pulley is wound up or down. At this time, even if the pulleys located in front and back when viewed from above move up and down, among the hoses that are wound up or down by each pulley, each continuous hose that makes up the same piping route is viewed from the driver's seat side. The images appear to overlap in the front and back direction for each series. Therefore, the area between the left and right inner masts that is obstructed by the hoisted or hoisted down hose is minimized, and visibility in front of the forklift can be secured well.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3.

Both left and right outer masts 1 are erected on both left and right sides of the front part of the machine stand (not shown), and inside the left and right outer masts 1, both left and right middle masts 2 are installed with rollers 3.
It is supported so that it can move up and down. Further, inside the left and right middle masts 2, left and right inner masts 4 are supported via rollers 5 so as to be movable up and down. The outer mast 1, the middle mast 2, and the inner mast 4 form a three-stage mast 1,
2 and 4 are configured. A lift bracket 6 is attached to the front of these three-stage masts 1, 2, and 4. This lift bracket 6 consists of an upper fork bar 7, a lower fork bar 8, and a rear plate 9 fixed to both left and right rear surfaces of these bars. It is supported so that it can move up and down. In addition, this lift bracket 6
Various attachments (not shown) are attached to the .

Behind the left and right middle masts 2, a rear lift cylinder 11 is erected on a lower tie beam 1a between the lower parts of the left and right outer masts 1, and a piston rod 11a at the upper end of the cylinder 11 is installed between the upper parts of the left and right middle masts 2. It is connected to the tie beam 2c. A chain wheel 12 is supported on both left and right sides of the upper tie beam 2c of the middle mast 2 behind the inner mast 4 and adjacent to the inside of the rear lift cylinder 11, and a chain 13 is wound around the chain wheel 12. one end 13a of which is attached to both the left and right outer masts 1.
The other end 13b is attached to the lower rear surface of both the left and right inner masts 4, respectively. A front cylinder 14 is erected on the lower tie beam 4a of the inner mast 4 at the center between both inner masts 4, and a chain wheel 16 is supported on both left and right sides of a base plate 15 fixed to a piston rod 14a at the upper end of the front cylinder. A chain 17 is wound around the wheel 16, and one end 17a of the chain 17 is wound around the wheel 16.
is attached to the middle tie beam 4b between the intermediate portions of the left and right inner masts 4, and the other end 17b is attached to the lift bracket 6, respectively.

A bracket 18 fixed on the base plate 15 of the piston rod 14a between the left and right chain wheels 16 of the front cylinder 14 supports a pair of left and right pulleys 19. In the range E) between the outer end surfaces of the wheels 16, a pair of left and right pulleys 20 are attached to the upper tie beam 2c of the middle mast 2, as seen from above, and the pulleys 19
It is supported in a position directly behind the Four mast pipes 21 are fixed to the middle tie beam 1b between the intermediate parts of the left and right outer masts 1, and four mast pipes are fixed to the middle tie beam 4b of the inner mast 4 and the lower oak bar 8 of the lift bracket 6, respectively. Connector pipes 22 and 23 are fixed. As shown in FIG. 3, the opening of the connector pipe 22 on the oil control valve 24 side, the openings of the connector pipe 23 on the lift bracket 6 side and the oil control valve 24 side, and the openings of the mast pipe 21 on the lift bracket 6 side The opening is located between both pulleys 1 when viewed from above.
It is located on the same line as 9 and 20 in the front-rear direction. Also, both pulleys 19, 20 are
It is located on a line connecting the corresponding front and rear openings of the respective pipes 21, 22, 23, which are connected by hoses 27, 26, which will be described later, and which are wrapped around the pipes 21, 22, 23, respectively. Four hoses 25 are connected between the oil control valve 24 installed on the driver's seat side (not shown) of the machine and the lower end of each mast pipe 21.
is connected, and between the upper end of this mast pipe 21 and the lower end of the connector pipe 22 of the inner mast 4, four hoses 26 wound around the pulley 20 of the middle mast 2 are connected, and A pulley 1 on the front cylinder 14 is connected between the upper end of the connector pipe 22 and the lower end of the connector pipe 23 of the lift bracket 6.
Four hoses 27 wrapped around 9 are connected. These hose 25, mast pipe 21, hose 26, connector pipe 22, hose 27, and connector pipe 23 form hydraulic piping that connects the oil control valve 24 and various attachments (not shown) on the lift bracket 6. It is starting to be configured.

Now, when the piston rod 14a of the front cylinder 14 rises from the lowest position of the lift bracket 6 shown in FIGS.
6 and pulley 19 also rise, and the chain 17 is hoisted up by the chain wheel 16, so that only the lift bracket 6 rises relative to the inner mast 4. At this time, the hose 27 is also wound up by the pulley 19. Thereafter, when the piston rod 14a reaches its maximum extension position, the lifting movement of the lift bracket 6 relative to the inner mast 4 is stopped. Next, the piston rod 1 of the rear lift cylinder 11
When 1a rises, the middle mast 2 rises, and the chain wheel 12 and pulley 20 also rise, the chain 13 is hoisted up by the chain wheel 12, and the inner mast 4 lifts the lift bracket at twice the rising speed of the middle mast 2. It rises at the same time as 6. At this time, the hose 26 is also wound up by the pulley 20.

On the other hand, when the piston rod 11a of the rear lift cylinder 11 descends from the highest position (not shown) of the lift bracket 6, the middle mast 2 descends, the chain wheel 12 and the pulley 20 also descend, and the chain 13 moves to the chain wheel 12. The inner mast 4 is hoisted down and lowered simultaneously with the lift bracket 6 at twice the lowering speed of the middle mast 2. At this time,
Hose 26 is also lowered by pulley 20.
Thereafter, when the lowering movement of the piston rod 11a stops, the lowering movements of the middle mast 2 and the inner mast 4 also stop. Next, the front cylinder 14
When the piston rod 14a is lowered, the chain wheel 16 and pulley 19 are also lowered, the chain 17 is hoisted down by the chain wheel 16, and only the lift bracket 6 is lowered relative to the inner mast 4. At this time, the hose 27 and the pulley 19
It is rolled down by

As described above, in this embodiment, among the hydraulic pipes connecting the oil control valve 24 on the machine base and various attachments on the lift bracket 6, the connector pipes 22, 23 and the mast pipe are connected by both hoses 26, 27. The front and rear openings 21 corresponding to each other, and both the hoses 26 and 27
The pulleys 19 and 20 around which the hoses are wound are arranged on the same line in the front and back direction when viewed from above, so when the piston rod 14a or the middle mast 2 is raised and lowered, the hoses 26 and 27 are Each series appears to overlap. Therefore, the area between the left and right inner masts 4, 4 that is blocked by both hoses 26, 27 is minimized, and compared to the conventional example, the field of view in front of the forklift can be secured better through between the left and right inner masts 4, 4. .

In particular, in this embodiment, a front cylinder 14 is provided upright in the center between the left and right inner masts 4, 4, and left and right chain wheels 1 are supported on both left and right sides of the upper end of the piston rod 14a of the cylinder 14.
6, that is, inside the range E between the outer end surfaces of both chain wheels 16, the front cylinder 14
In addition, each pulley 19, 20 and each hose 26, 27, and each pipe 21, 22, 23 connected by both hoses 26, 27 are provided with corresponding front and rear openings, thereby creating a member that blocks the front view of the forklift. can be gathered in the center between the left and right inner masts 4, 4, and both the left and right spaces S outside the range E between the outer end surfaces of the chain wheels 16 are always left unobstructed.
Therefore, the field of vision in front of the forklift from the driver's seat is even better.

Although the above-described embodiment has a four-line hydraulic piping structure, the number of piping routes can be changed arbitrarily depending on the type of oil control valve 24, etc.

Effects of the invention As detailed above, according to this invention, among the hydraulic piping inside the mast, the piping is wound around the pulley provided on the piston rod of the inner mast and the pulley on the middle mast, respectively, to form the same piping route. When each continuous hose moves up and down, it appears to overlap in the front and back direction when viewed from the driver's seat, so the area obstructed by each continuous hose between the left and right inner masts can be minimized, and the three-stage mast type This has an excellent practical effect in that it is possible to improve the visibility in front of the forklift in a forklift and improve work efficiency.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of only the mast section of a three-stage mast forklift according to an embodiment of the present invention viewed from the driver's seat side, and Fig. 2 is a schematic vertical cross-section of only the mast section viewed from the side. Similarly, FIG. 3 is a schematic cross-sectional view of only the mast portion, and FIG. 4 is a schematic cross-sectional view of only the mast portion of a conventional three-stage mast type forklift. 1 is the outer mast, 2 is the middle mast, 4 is the inner mast, 6 is the lift bracket, 11 is the rear lift cylinder, 12 is the chain wheel, 13
is a chain, 14 is a front cylinder, 16 is a chain wheel, 17 is a chain, 19 is a pulley, 20 is a pulley, 21 is a mast pipe, 22 is a connector pipe, 23 is a connector pipe, 24 is an oil control valve, 25 is a hose, 26
is a hose, and 27 is a hose.

Claims (1)

[Scope of Claim for Utility Model Registration] Left and right middle masts are operatively connected to the left and right outer masts installed on the machine stand so that they can move up and down, and both left and right inner masts are operably connected to the middle mast so that they can move up and down. A cylinder equipped with a piston rod that is driven up and down is installed on the inner mast, and a lift bracket that is moved based on the drive of the cylinder is supported in a vertically movable manner, and various attachments on this lift bracket and the operation of the machine base are Hydraulic piping connecting the oil control valve mounted on the seat side is arranged between the left and right inner masts, and pulleys around which the hoses of the hydraulic piping are wound are provided on the piston rod of the cylinder and on the middle mast, respectively. In the three-stage mast type forklift, among the hydraulic piping, an opening on the oil control valve side of the connector pipe attached to the lift bracket, and each opening on the lift bracket side and the oil control valve side of the connector pipe attached to the inner mast. The lift bracket side opening of the mast pipe attached to the outer mast, the pulley provided on the piston rod, and the pulley provided on the middle mast are arranged substantially on the same line in the front-rear direction when viewed from above. , an in-mast hydraulic piping structure in a three-stage mast type forklift, in which hoses connecting the openings of the pipes located in front and back and corresponding to each other are wound around each of the pulleys.