JP2013147332A - Hydraulic device of full free mast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a front view of a forklift having a full free mast.SOLUTION: A hydraulic device of a full free mast with a full free cylinder for lifting a fork and a lift cylinder for lifting the full free cylinder along with the fork while actuating the lift cylinder after activation of the full free cylinder includes: a main hose for branching and discharging hydraulic oil sent under pressure from a hydraulic source to two ways at a branch part formed at an end; a full free hose which is connected to one way of the branch part via a rotary joint, and supplies the full free cylinder with the hydraulic oil discharged from the main hose; and a lift hose which is connected to the other way of the branch part, and supplies the lift cylinder with the hydraulic oil discharged from the main hose.

Description

  The present invention relates to a full free mast hydraulic device.

  Patent Document 1 discloses a full free mast hydraulic device including a full free cylinder for raising and lowering a fork and a lift cylinder for raising and lowering the full free cylinder together with the fork. Patent Document 2 discloses a full-free mast hydraulic device that uses a ram-type cylinder as a lift cylinder and supplies hydraulic oil that has passed through the inside of the lift cylinder to the full-free cylinder.

Japanese Patent Laid-Open No. 6-298396 JP 2000-344487 A

  However, the thing of patent document 1 needed to make the hose which supplies hydraulic oil to a full free cylinder into a U shape, and there existed a problem that a front view was bad.

  The present invention has been made paying attention to such problems, and an object thereof is to ensure a good forward view.

  The present invention is a full free mast hydraulic device that includes a full free cylinder that raises and lowers a fork and a lift cylinder that raises and lowers the full free cylinder together with the fork, and operates the lift cylinder after the full free cylinder is operated. The main hose that divides the hydraulic oil pumped from the source into two hands at the branch portion formed at the end and discharges it, and the operation that is connected to one of the branch portions via a rotary joint and discharged from the main hose A full free hose that supplies oil to the full free cylinder and a lift hose that is connected to the other of the branch portions and supplies hydraulic oil discharged from the main hose to the lift cylinder.

  According to the present invention, the full free cylinder rises while the rotary joint rotates while the lift cylinder operates. Therefore, in order to prevent the hose from being twisted, it is not necessary to set an extra hose length of the full free hose, and the length of the full free hose can be shortened. Thereby, it is not necessary to arrange the full free hose in a U shape before the lift cylinder is operated, so that a good front view can be secured.

1 is a schematic side view of a two-stage full free mast according to an embodiment of the present invention. It is a figure which shows operation | movement of the two-stage type full free mast by one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a two-stage full free mast hydraulic device according to an embodiment of the present invention. It is a figure explaining the hydraulic device of the two-stage type full free mast by a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A two-stage full free mast 1 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic side view of a two-stage full free mast 1. FIG. 2 is a diagram illustrating the operation of the two-stage full free mast 1.

  The two-stage full free mast 1 is a device that is attached to a forklift and lifts the cargo handling to a required height. First, the configuration of the two-stage full free mast 1 will be described with reference to FIG.

  The two-stage full free mast 1 includes an outer mast 2, a lift cylinder 3, an inner mast 4, a full free cylinder 5, and a fork 6 for loading a load.

  The outer mast 2 is attached to the body of the forklift and functions as a guide rail for the inner mast 4. One outer mast 2 is provided on each of the left and right sides of the forklift so as to form a pair, and the lower ends thereof are connected by the lower beam 2a.

  The lift cylinder 3 is a piston-type hydraulic cylinder and is provided in the lower beam 2 a of the outer mast 2. One lift cylinder 3 is provided on each side of the forklift so as to form a pair. The tip of the piston rod 3 a of the lift cylinder 3 is connected to the upper end of the inner mast 4 via the bracket 31.

  The inner mast 4 is provided on the inner side of the outer mast 2 (the inner side in the left-right direction of the forklift) and functions as a guide rail for the fork 6. One inner mast 4 is provided on each of the left and right sides of the forklift so as to form a pair, and the lower ends thereof are connected by a tie beam 4a. The inner mast 4 moves up and down along the outer mast 2 in accordance with the expansion and contraction of the piston rod 3 a of the lift cylinder 3.

  The full free cylinder 5 is a piston-type hydraulic cylinder, and one full free cylinder 5 is provided at a substantially central portion of the tie beam 4 a of the inner mast 4. A chain wheel 7 is provided at the tip of the piston rod 5 a of the full free cylinder 5. A chain 8 having one end fixed to the fork 6 and the other end fixed to the inner mast 4 is wound around the chain wheel 7.

  The fork 6 moves up and down along the inner mast 4 in accordance with the expansion and contraction of the piston rod 5 a of the full free cylinder 5.

  The two-stage full free mast 1 is configured as described above. As shown in FIG. 2, first, the piston rod 5a of the full free cylinder 5 extends and the fork 6 rises. When the piston rod 5a of the full free cylinder 5 extends to the maximum, the piston rod 3a of the lift cylinder 3 extends, the inner mast 4 rises, and the fork 6 further rises. The two-stage full free mast 1 supplies the hydraulic oil to the full free cylinder 5 and the lift cylinder 3 so that the full free cylinder 5 is operated in advance and the lift cylinder 3 is operated subsequently. A hydraulic device 10 is further provided.

  In the following, in order to facilitate understanding of the invention, first, the hydraulic device 100 of the two-stage full free mast 1 according to the comparative example will be described, and then the hydraulic device of the two-stage full free mast 1 according to one embodiment of the present invention. 10 will be described.

  FIG. 4 is a diagram for explaining the hydraulic device 100 of the two-stage full free mast 1 according to the comparative example. FIG. 4 (A) shows a state when the fork 6 is at the lowest position, and FIG. A state when the fork 6 is at the highest position is shown. FIG. 4 is a view of the hydraulic device 100 of the two-stage full-free mast 1 according to the comparative example viewed from the back side (driver side). In order to prevent the drawing from being complicated, a pair of lifts other than the hydraulic device 100 is used. Only the cylinder 3 and the full free cylinder 5 are described.

  As shown in FIG. 4, the hydraulic device 100 of the two-stage full-free mast 1 according to the comparative example has a main hose 102 into which hydraulic oil from the control valve 101 flows, and a pair of right and left hydraulic oil connected to the main hose 102. A lift hose 103 for supplying each of the lift cylinders 3, and a full free hose 104 connected to the lift hose 103 for supplying hydraulic oil to the full free cylinder 5. And each hose is arrange | positioned between the mast (outer mast 2 and inner mast 4) provided so that it might respectively become a pair on the right and left of a forklift.

  Here, in the case of the two-stage full free mast 1, as shown in FIG. 4B, the full free cylinder 5 itself rises as the piston rod 3a of the lift cylinder 3 extends. It is necessary to set the length of the free hose 104. Therefore, as shown in FIG. 4A, before the lift cylinder 3 is actuated, the full free hose 104 is arranged in a U-shape, which causes the front vision to deteriorate.

  Further, when the hydraulic oil is caused to flow into the full free hose 104 after passing through the lift hose 103, the pressure of the hydraulic oil supplied to the full free cylinder 5 by the pressure loss due to the full free hose 104 is supplied to the lift cylinder 3. It will be lower than the hydraulic oil pressure. Furthermore, when the length of the full free hose 104 is increased, the pressure loss is increased accordingly, and the pressure of the hydraulic oil supplied to the full free cylinder 5 is also reduced.

  Therefore, in order to operate the full free cylinder 5 in advance, it is necessary to make the diameter of the full free cylinder 5 (piston pressure receiving area) larger than the diameter of the lift cylinder 3, and the length of the full free hose 104 is long. It is necessary to increase the diameter of the full free cylinder 5 as the length increases. Since the full free cylinder 5 is arranged at the center between the masts, if the diameter of the full free cylinder 5 is increased, the front vision is deteriorated.

  So, in this embodiment, while shortening the length of the full free hose 104, the diameter of the full free cylinder 5 is made thin by equalizing the pressure loss of the full free hose 104 and the pressure loss of the lift hose 103, It was decided to improve the forward vision.

  FIG. 3 is a diagram illustrating the hydraulic device 10 of the two-stage full-free mast 1 according to an embodiment of the present invention, and FIG. 3 (A) shows a state when the fork 6 is at the lowest position. (B) shows a state when the fork 6 is at the highest position. 3 is a view of the hydraulic device 10 of the two-stage full free mast 1 as viewed from the back side (driver side). In order to prevent the drawing from being complicated, a pair of lift cylinders 3 and Only the full free cylinder 5 is shown.

  As shown in FIG. 3, the hydraulic device 10 of the two-stage full free mast 1 according to the present embodiment includes a control valve 11, a main hose 12, a first full free hose 13, a first swivel joint 14, 2 full free hoses 15, a second swivel joint 16, and a lift hose 17.

  The hydraulic oil pumped from an oil tank (not shown) in which the hydraulic oil is stored flows into the main hose 12 via the control valve 11.

  The main hose 12 has one end connected to the control valve 11 and the other end branched in two. One end of the other end of the main hose 12 branched in two is connected to the first full free hose 13 via the first swivel joint 14. The other of the other ends of the main hose 12 branched in two is connected to the lift hose 17.

  The first full free hose 13 has one end connected to the first swivel joint 14 and the other end connected to the second full free hose 15 via the second swivel joint 16.

  The first swivel joint 14 is a rotary joint that allows the first full free hose 13 to freely rotate in the vertical and horizontal directions with respect to the main hose 12.

  The second full free hose 15 has one end connected to the second swivel joint 16 and the other end connected to a bottom chamber formed inside the full free cylinder 5. By supplying hydraulic oil to the bottom chamber of the full free cylinder 5, the piston rod 5a of the full free cylinder 5 extends.

  The second swivel joint 16 is a rotary joint that allows the second full free hose 15 to freely rotate in the vertical direction and the horizontal direction with respect to the first full free hose 13.

  The lift hose 17 branches into two hands on the way and is connected to a bottom chamber formed inside the pair of left and right lift cylinders 3. When the hydraulic oil is supplied to the bottom chamber of the lift cylinder 3, the piston rod 3a of the lift cylinder 3 extends.

  In this way, the main hose 12 and the full free cylinder 5 are connected by using the two full free hoses 13 and 15 and the two swivel joints 14 and 16, so that the first time when the lift cylinder 3 is operated. The full free cylinder 5 rises while the swivel joint 14 and the second swivel joint 16 rotate. Therefore, it is not necessary to set an extra hose length to prevent the hose from being twisted, and the entire length of the full free hose can be shortened. As a result, as shown in FIG. 3 (A), it is not necessary to arrange the first full free hose 13 in a U shape before the lift cylinder 3 is actuated, so that a good front view can be ensured.

  Moreover, since it becomes possible to shorten the length of the whole full free hose, the length of the whole full free hose and the length of the lift hose 17 can be made into substantially the same length. Thus, the hydraulic oil is supplied to the lift cylinder 3 by setting the branch point of the hydraulic oil from the main hose 12 to the first full free hose 13 and the lift hose 17 so that the pressure loss from the main hose 12 becomes substantially the same. The pressure of the hydraulic oil to be supplied and the pressure of the hydraulic oil supplied to the full free cylinder 5 can be made substantially the same.

  Therefore, if the hose diameter of the lift hose 17 is set to be smaller than the hose diameters of the first full free hose 13 and the second full free hose 15, the pressure loss on the lift hose 17 side is reduced to the full free hoses 13, 15. Can be greater than the pressure loss on the side. That is, the pressure of the hydraulic oil supplied to the full free cylinder 5 can be made higher than the pressure of the hydraulic oil supplied to the lift cylinder 3. Thereby, even if the diameter of the lift cylinder 3 and the diameter of the full free cylinder 5 are the same, the full free cylinder 5 can be operated in advance. As a result, since the diameter of the full free cylinder 5 can be made thinner than that of the comparative example, it is possible to ensure a good front view.

  Further, in order to operate the full free cylinder 5 in advance, there is no need for a valve or the like for switching whether the hydraulic oil flows into the full free hoses 13 and 15 side or the lift hose 17 side. And a better front view can be secured.

  Furthermore, by using a piston-type cylinder instead of a ram-type cylinder as a lift cylinder, the unit price of the lift cylinder can be reduced, and a hose that connects the lift cylinder and the fully free cylinder is not required. Overall, cost can be reduced.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

1 Two-stage full free mast (full free mast)
3 Lift cylinder 5 Full free cylinder 6 Fork 10 Hydraulic device 12 Main hose 13 First full free hose (full free hose, first hose)
14 First swivel joint (rotating joint)
15 Second full free hose (full free hose, second hose)
16 Second swivel joint (second rotary joint)

Claims (4)

A full free cylinder to raise and lower the fork,
A lift cylinder for raising and lowering the full free cylinder together with the fork;
A full-free mast hydraulic device that operates the lift cylinder after the full-free cylinder is operated,
A main hose that discharges hydraulic oil pumped from a hydraulic source in two branches at a branch formed at the end;
A full free hose connected to one of the branch parts via a rotary joint and supplying hydraulic oil discharged from the main hose to the full free cylinder;
A lift hose connected to the other of the branch parts and supplying hydraulic oil discharged from the main hose to the lift cylinder;
A full-free mast hydraulic device comprising: The branch portion is disposed at a position where the pressure loss due to the full free hose and the pressure loss due to the lift hose are substantially the same.
The full free mast hydraulic device according to claim 1. The diameter of the lift hose is made smaller than the diameter of the full free hose, and the diameter of the full free cylinder is substantially the same as the lift cylinder.
The fully free mast hydraulic device according to claim 2. The full free hose is
A first hose having one end connected to the rotary joint and the other end connected to the inlet side of the second rotary joint;
A second hose having one end connected to the outlet side of the second rotary joint and the other end connected to the full free cylinder;
The fully free mast hydraulic device according to any one of claims 1 to 3, further comprising:

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