JPH0450319Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a side forklift in which the mast is capable of reciprocating in the lateral direction of the machine. The present invention relates to a device for automatically reducing the speed of movement of a mast.

[Prior Art] There have been various types of side forklifts that are equipped with a fork and a mast for raising and lowering the fork on the side of the machine platform.In the side forklift 1 shown in FIG. It is a so-called reach type that can move laterally on the machine.

The illustrated side forklift 1 has a loading platform 3 on one side of the machine platform, and the loading platform 3 is divided into front and rear sections with a certain gap in between. Guide rails 4 are installed in parallel and horizontally on the opposing surfaces of the front and rear loading platforms 3, respectively. Each guide rail 4 is engaged with a roller 6 provided on the lower side surface of the outer mast 5 of the mast 2, so that the mast 2 reciprocates along the guide rail 4 in the lateral direction of the machine base. can move. Further, a reach pillar 7 is attached to the base on the rear side of the mast 2 and extends upward, and a cylinder tube 8a of a reach cylinder 8 is pivotally supported on the upper part of the reach pillar 7. The tip of the piston rod 8b of the reach cylinder 8 is pivotally supported at the lower center of the mast 2, and by applying hydraulic pressure to the reach cylinder 8, the mast 2 can be reciprocated.

The side forklift 1 with such a configuration is
By pulling the mast 2 into the machine frame, the cargo on the fork 9 can be transferred to the loading platform 3, which is effective for transporting long objects.

[Problems to be solved by the invention] In the above-mentioned side forklift, a stopper is provided at the tip of the guide rail in order to prevent the mast from falling off the guide rail. There was a problem in that the conventional structure did not have a shock prevention means and could receive a very large shock when they came into contact with each other. In other words, conventionally, the moving speed of the mast is controlled only by manual operation of the reach lever, but if the mast is not decelerated until it contacts the stopper, the contact will cause a large impact, which may adversely affect the machine or cause operational problems. There was a risk of making people feel uncomfortable.

The purpose of this invention is to solve these problems.

[Means for solving the problem] This invention is a reach type side forklift in which a reduction valve consisting of a flow control valve and a check valve connected in parallel is connected between a reach cylinder and a control valve. Interposed in the hydraulic pipeline, when the mast is pushed out, the reach cylinder tilts upward from a predetermined angle of inclination, and the spool of the flow control valve is moved to gradually reduce the flow rate passing through the deceleration valve. It features an automatic side forklift mast deceleration device that allows hydraulic oil to flow through a check valve when the mast is pulled back. In addition, in this invention, the deceleration valve body of the deceleration valve is attached to the upper end of the reach pillar with bolts so that the tip of the spool of the flow rate control valve protruding from the body is pushed by the side of the cylinder tube of the reach cylinder. Another feature is that the bolt hole of the reach pillar that receives the bolt is an elongated hole extending in the vertical direction.

[Function] In the mast automatic deceleration device according to this invention as described above, the mast is automatically decelerated when it approaches the stopper, so that the impact caused by contact between the mast and the stopper can be minimized. . Furthermore, when the mast is pulled back, the hydraulic oil flows through the check valve, so the mast can be quickly pulled back without being affected by the flow control valve.

Furthermore, since the bolt hole for attaching the deceleration valve is an elongated hole extending vertically, the attachment position of the deceleration valve can be changed, and the degree of deceleration can be finely adjusted.

[Embodiment] Hereinafter, a preferred embodiment of the automatic mast reduction device for a side forklift according to this invention will be described in detail with reference to the drawings.

Note that the same reference numerals are given to the same or corresponding parts as in the conventional configuration described above.

The side forklift to which this invention is applied, as schematically shown in FIG. A mast 2 is movably mounted, a reach pillar 7 is mounted on a base on the rear side of the mast 2, one end is pivoted to the lower center of the mast 2, and the other end is pivoted to the upper part of the reach pillar 7. A supported reach cylinder 8 is provided.

A mounting plate 10 is fixed to the upper end of the reach pillar 7, and a deceleration valve 11 is bolted to this mounting plate 10. As understood from FIG. 2, the deceleration valve 11 is constructed by connecting a flow control valve 12 and a check valve 13 in parallel. The flow rate control valve 12 is of a spring return type that is normally open, and one end of a spool 14 protrudes from the deceleration valve body, and by pushing the spool 14, the inlet port 1
5 to the outlet port 16 can be reduced. The deceleration valve 11 closes the spool 14 when the reach cylinder 8 tilts upward.
The roller 17 at the tip of the reach cylinder 8 is attached so as to be in contact with the cylinder tube 8a and pushed into the deceleration valve body. The installation position of this reduction valve 11 is such that the cylinder tube 8a comes into contact with the spool 14 only when the mast 2 is located near the stopper 18 at the tip of the guide rail 4.
Moreover, it is preferable that the spool 14 be pushed in the most when the mast 2 comes into contact with the stopper 18.

The deceleration valve 11 is interposed in a hydraulic conduit between the reach cylinder 8 and a control valve 19 in a hydraulic circuit related thereto. In this embodiment, the port 20 of the reach cylinder 8 on the piston rod 8b side is connected to the inlet port 15 of the reduction valve 11, and the outlet port 16 is connected to the control valve 19.
(Figure 2).

Next, in such a configuration, the operation of the mast automatic speed reduction device of this invention will be explained.

When the mast 2 is located from near the center of the guide rail 4 to the reach pillar 7 side, the deceleration valve 11
The spool 14 is separated from the reach cylinder 8, and the flow path in the reduction valve 11 is fully open. Therefore, in this case, the moving speed of the mast 2 is determined only by the position of the control valve 19.

Furthermore, when the mast 2 is pushed out by the reach cylinder 8, the reach cylinder 8 also tilts upward,
The spool 14 and the cylinder tube 8a come into contact with each other at a predetermined angle of inclination, and the cylinder tube 8a soon begins to push the spool 14. As a result, the flow path in the deceleration valve 11 is narrowed, and the flow rate of the hydraulic oil supplied to the reach cylinder 8 is gradually reduced, and the mast 2
movement speed is reduced. In this way, stopper 1
Just before 8, mast 2 is at its lowest speed;
Even if it contacts the stopper 18, the impact will be extremely small.

When the mast 2 is pulled back from the state in which the spool 14 is pushed in, that is, when the flow of hydraulic oil to the reach cylinder 8 is reversed, the hydraulic oil does not pass through the flow control valve 12 because the restriction is large. , through the check valve 13, and the mast 2 is quickly pulled back.

In addition, since the bolt hole 21 of the deceleration valve mounting part of the mounting plate 10 is a long hole extending vertically, by changing the mounting position of the deceleration valve 11 vertically,
The degree of deceleration can be finely adjusted.

[Effects of the invention] As described above, according to this invention, the mast is automatically decelerated as it approaches the stopper, so that the impact caused by contact between the mast and the stopper can be minimized. Therefore, the adverse effect on the machine base due to impact is eliminated, the life of the side forklift can be extended, and the comfort of the vehicle is also improved.

Furthermore, since the mast can be quickly pulled back using the check valve, there is no reduction in work efficiency.

Furthermore, since the tip of the spool protruding from the reduction valve is configured to directly contact the cylinder tube of the reach cylinder, no special member is required to drive the spool, and it can be easily applied to existing side forklifts. is possible.

In addition, the position of the reduction valve can be changed up or down, so
The degree of deceleration can be easily adjusted.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing an embodiment of an automatic mast reduction device for a side forklift according to this invention, Fig. 2 is a circuit diagram showing a hydraulic circuit of the mast automatic reduction device according to this invention, and Fig. 3 is a FIG. 2 is a perspective view showing a conventional side forklift. In the diagram, 1...Side forklift, 2...Mast,
4... Guide rail, 7... Reach pillar, 8...
Reach cylinder, 11... Reduction valve, 12... Flow rate control valve, 13... Check valve, 14... Spool, 1
8...Stopper, 19...Control valve.

Claims (1)

[Scope of utility model registration request] a mast mounted so as to be reciprocally movable in the lateral direction of the machine base with respect to a pair of guide rails provided on the machine base; a reach pillar extending upward and attached to the machine base on the rear side of the mast; A side forklift comprising a reach cylinder having one end pivoted to the lower center of the mast and the other end pivoted to the upper part of the reach pillar so as to be tiltable up and down as the mast reciprocates. , a deceleration valve consisting of a flow control valve and a check valve connected in parallel is interposed in a hydraulic conduit connecting the reach cylinder and the control valve, and when the mast is pushed out, the reach cylinder moves to a predetermined position. The spool of the flow control valve is moved to gradually reduce the flow rate passing through the deceleration valve as the mast is tilted upward from the inclination angle of the mast, and when the mast is pulled back, hydraulic fluid flows through the check valve. In the mast automatic speed reduction device, the speed reduction valve body is moved such that the tip of the spool of the flow rate control valve protruding from the speed reduction valve body of the speed reduction valve is pushed by the side surface of the cylinder tube of the reach cylinder. An automatic mast reduction device for a side forklift, characterized in that the reach pillar is attached to an upper end portion of the reach pillar with a bolt, and the bolt hole of the reach pillar is an elongated hole extending in the vertical direction to receive the bolt.