JPH11116192A - Lift chain buffer structure of forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of damage and striking sound due to the interference with mast members by a lift chain by covering the outside face of an outer mast opposed to the lift chain with a buffer member. SOLUTION: This structure is constituted by covering the front surface sides of mast members in the vicinity of a lift chain 40 suspended via a sprocket 42, for instance, that is, an outer mast 10, an upper finger bar 24 and a cylinder part 54 of a tilt cylinder 52 with each of buffer members made of elastic members such as rubber and synthetic resin. Therefore, a lift chain 40 collides with opposed buffer members and is not directly abutted on metallic mast members such as the outer mast 10, a lower finger bar 26 and the cylinder part 54, even when this lift chain 40 largely vibrates as shown by a virtual line F1 due to vibration of a car body during a traveling. Therefore, interference shock is mitigated and generation of damage and striking sound of the lift chain 40 and the mast members is effectively suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift for raising and lowering a carriage for supporting a fork by a lift chain, and more particularly, to a hitting noise caused by a slackened lift chain interfering with a mast, etc. The present invention relates to a cushion structure for a lift chain that reduces damage to a mast.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a good front view of a forklift, an inner mast is conventionally housed in an outer mast, and a lift chain for moving a fork carriage up and down with respect to the inner mast is arranged outside the outer mast. Is known.

As an example, FIG. 11 shows a structure of a forklift disclosed in Japanese Patent Application Laid-Open No. Hei 3-232697.
The pair of left and right outer masts 1 are formed in a substantially U-shaped cross section,
In this U-shaped space, a pair of left and right inner masts 2 also having a substantially U-shaped cross section are housed and arranged so as to be able to move up and down. Here, the upper tie beam 2a connecting the left and right inner masts 2 is extended so as to wrap around the outer mast 1, and a chain wheel 4 is attached to the overhanging portion 3. A lift chain 5 for lifting and lowering a fork carriage 6 is suspended.

[0004]

For example, when the vehicle travels under no load with no load, the tension applied to the lift chain 5 is extremely small, and the long chain portion along the outer surface of the outer mast 1 Looseness and vibration may cause large vibration. For this reason, the lift chain 5 may interfere with the outer surface of the outer mast 1, the front surface of the tie beam 2a, or the like, causing a hitting sound or damage.

[0005] The present invention has been made in view of such problems of the prior art, and effectively prevents damage and hitting noise caused by interference of a lift chain with a mast member while securing a good front view. It is an object of the present invention to provide a lift chain buffer structure for a forklift that can be prevented.

[0006]

Therefore, according to the present invention, the inner mast is arranged inside the outer mast in the vehicle width direction so as to be able to move up and down, and the carriage supporting the fork is suspended so as to be able to move up and down. In a forklift arranged outside the outer mast,
At least the cushioning member was provided on the outer surface of the outer mast facing the lift chain.

[0007] Since the lift chains are arranged outside the outer mast, the insides of both inner masts are greatly opened as viewed from the operator, and a good front view can be obtained.

[0008] Even if the lift chain vibrates greatly while traveling under no load, for example, the lift chain does not directly interfere with the outer surface of the outer mast, but abuts on the cushioning member mounted thereon. Accordingly, it is possible to effectively prevent damage and hitting sound due to interference between the lift chain and the outer mast.

[0009] In the invention of claim 2, the lift chain is suspended by a sprocket mounted on the upper part of the inner mast, and one end on the front side is connected to the carriage and the other end on the rear side is connected to the outer mast side. The outer portion of the cushioning member mounted on the outer surface of the outer mast is characterized by being disposed in a substantially front area from a line connecting one end to the other end of the lift chain when viewed from the side. .

That is, since the lift chain is appropriately provided in the outer mast outer surface in accordance with the region facing the lift chain, the interference between the lift chain and the outer mast is reliably avoided as described above, and And the material cost is reduced. Further, since the cushioning member can be attached without interfering with the connection portion or the like at the end of the lift chain, the attachment property is improved.

According to a third aspect of the present invention, a cylindrical portion rotatably fitted to a tilt pin fixed to an outer surface of the outer mast is provided at a tip of a piston rod of the tilt cylinder for tilting the outer mast. A cushioning member is provided on the outer peripheral surface facing the lift chain.

In this case, it is possible to prevent damage and hitting sound caused by direct interference between the cylindrical portion of the tilt cylinder and the lift chain.

According to a fourth aspect of the present invention, a tip of a piston rod of a tilt cylinder for tilting the outer mast is rotatably connected to a tilt bracket provided on an outer surface of the outer mast, and the lift chain of the tilt bracket is provided. A cushioning member is provided on the outer peripheral surface facing the above.

In this case, it is possible to avoid damage and hitting sound caused by direct interference between the lift cylinder and the tilt cylinder provided on the outer mast.

According to a fifth aspect of the present invention, a front end of the lift chain is fixed to a lower finger bar of the carriage, and a cushioning member is mounted on an upper finger bar of the carriage facing the lift chain. I have.

In this case, it is possible to reliably prevent damage and hitting sound caused by direct interference between the fork carriage and the lift chain.

[0017]

As described above, according to the present invention, it is possible to effectively prevent damage and hitting noise caused by the lift chain directly interfering with the mast member such as the outer mast while securing a good view. can do.

[0018]

1 to 8 show a front mast portion of a forklift to which a lift chain buffer structure according to an embodiment of the present invention is applied. FIG. 2 shows the foremost lowering state in which the fork 20 is at the maximum lowering position.
FIG. 3 shows the fork 20 in the highest position in which the fork 20 is at the highest position, and FIG. 1 shows a state in which the fork 20 is moved from the lowest position in FIG. Free lift section (eg 300mm)
This shows a free lift state that has just risen.

A pair of left and right outer masts 10 are attached to the front of the vehicle body so as to be tiltable forward and backward. Each of the outer masts 10 is formed in a substantially U-shaped cross section that opens inward in the vehicle width direction, and is connected and fixed to each other by a cross beam 12 on the upper back side.

Inside the outer mast 10, a pair of left and right inner masts 14 are arranged side by side via a lift roller 16 so as to be vertically movable. Each inner mast 14
Like the outer mast 10, it is formed in a substantially U-shaped cross section that opens inward, and the upper back surface thereof has an upper tie beam 18.
Are connected to each other.

A carriage 2 for supporting a fork 20 is provided in front of the outer mast 10 and the inner mast 14.
2 are provided. As shown in FIG. 5, the carriage 22 has a pair of upper and lower upper finger bars 24 and a lower finger bar 26 extending in the vehicle width direction, and a pair of left and right roller brackets 28 fixed across the finger bars 24 and 26. , A plurality of lift rollers 30 are respectively attached. These lift rollers 30
Are movably engaged in the U-shaped space of the inner mast 14, as shown in FIG.

A pair of lift cylinders 32 are fixed behind the outer mast 10 via a cylinder support 34 and the like. The lift cylinder 32 has an upper end of a piston rod 32a fixed to the upper tie beam 18 side. When the piston rod 32a moves forward and backward, the inner mast 14 moves up and down with respect to the outer mast 10.

As shown in FIG. 4, the upper tie beam 18 has both left and right ends projecting further outward in the vehicle width direction than the outer side surface 10a of the outer mast 10 in the vehicle width direction. 38 are fixed. Note that the upper tie beam 18 and the sprocket plate 38 may be integrated. The sprocket 42 on which the lift chain 40 is suspended is attached to the inner surface of the sprocket plate 38 facing the outer surface 10a of the outer mast 10.

The lift chain 40 has one end 4 on its front side.
0a is connected to an anchor bolt 46 fixed to the lower finger bar 26 of the carriage 22 via an anchor bracket 44, and the other end 40b on the rear side is fixed to the outer surface of the outer mast 10 via an adjustment bracket 48. It is connected to an adjustment bolt (anchor bolt) 50.

As described above, since the inner mast 14 is arranged along the inner side of the outer mast 10 and the lift chain 40 is arranged along the outer side of the outer mast 10, the inner regions of both inner masts 14 as viewed from the operator are reduced. It can be released greatly and a good front view can be obtained.

A tilt cylinder 52 is connected to the outer surface of the outer mast 10. That is, the rear end of the tilt cylinder 52 is attached to the vehicle body (not shown), and the cylindrical portion 54 provided at the front end of the piston rod 52a is rotatably fitted to the tilt pin 56 fixed to the outer surface of the outer mast 10. Have been.

With the above configuration, when the piston rod 32a moves forward and backward by driving the lift cylinder 32,
The inner mast 14 moves up and down with respect to the outer mast 10, and the carriage 22 further moves up and down with respect to the inner mast 14 via the lift chain 40.

When the piston rod 52a moves forward and backward by the operation of the tilt cylinder 52, the entire mast including the outer mast 10 tilts in the front-rear direction with its lower end as a center.

Here, in the present embodiment, the mast member in the vicinity of the lift chain 40 suspended via the sprocket 42 is provided with buffer members 62, 64 made of an elastic member such as rubber or synthetic resin. 66 are respectively mounted. Specifically, as shown in FIGS. 1 to 4, the outer mast 10 facing the inside of the lift chain 40 is provided with a first cushioning member 62 from the outer side surface 10 a to the front side surface 10 b. As shown in FIGS. 4 and 5, the upper finger bar 24 of the carriage 22 located in front of the chain 40 is provided with a second cushioning member 64, and a tilt cylinder 52 provided on the rear side of the lift chain 40. A third cushioning member 66 is mounted on the front side of the cylindrical portion 54 as shown in FIGS.

Therefore, for example, a case where the forklift travels in the free lift state shown in FIG. 1 and the lift chain 40 largely shakes as shown by the imaginary line F1 in FIG. The lift chain 40 abuts against the cushioning members 62, 64, 66 facing each other, and the outer mast 10, the lower finger bar 26, and the cylindrical portion 5.
4 does not directly contact the metal mast member, so that the interference impact is reduced and the lift chain 40
Damage to the mast member and occurrence of a tapping sound are effectively suppressed.

In particular, the outer portion of the first cushioning member 62 provided on the outer surface 10a of the outer mast 10 covers the swing range of the lift chain 40 when viewed from the side, and the mounting bracket of the adjust bracket 48 and the tilt pin 56 5
6a has an appropriate shape without interfering with the shape. More specifically, in the free lift state as shown in FIG.
In the region above the other end 40b of the outer mast 10, the first buffer member 62 extends to both front and rear ends of the outer mast 10.
In the region below 0b, the width gradually decreases toward the portion where the lift chain 40 is connected to the anchor bolt 46. In other words, the outer portion of the first cushioning member 62 has a line L connecting one end 40a connected to the anchor bolt 46 and the other end 40b connected to the adjustment bolt 50 in the free lift state as shown in FIG. On the other hand,
It extends substantially to the front region as viewed from the side.

Therefore, the first cushioning member 62 can be attached without interfering with the brackets 44 and 48, the attachment bracket 56a of the tilt pin 56, and the like. Since the mounting area is minimized, the material cost can be effectively reduced.

In the highest state as shown in FIG.
The outer surface of the inner mast 14 faces the lift chain 40 when viewed from the side.
Since the outer side surface and the lift chain 40 are separated by a predetermined amount in the vehicle width direction, even if the lift chain 40 swings as shown by a virtual line F2, the lift chain 4
0 does not interfere with the inner mast 14. Therefore, in the present embodiment, the buffer member is not provided on the outer surface of the inner mast 14, while the first buffer member 62 described above is provided on the outer surface 10 a of the outer mast 10 that may interfere with the lift chain 40. It is attached.

The present invention is not limited to the structure of the embodiment described above, and various applications are possible without departing from the gist thereof.

For example, in the structure shown in FIGS. 9 and 10, a clevis-shaped tilt bracket 58 is fixed to the outer side surface 10a of the outer mast 10 instead of the tilt pin 56 of the above embodiment. That is, the tilt bracket 58 has a semi-cylindrical support bracket 58b on the outer periphery of the pair of annular portions 58a.
Is provided. Then, by inserting the shaft pin 60 in a state where the cylindrical portion 54 of the tilt cylinder 52 is fitted between the two annular portions 58a, the outer cylinder 10 is pivotally movable about the shaft pin 60.
Attached to.

In such a structure, the front outer peripheral surface of the support bracket 58b of the tilt bracket 58 faces the lift chain 40. Therefore, the fourth cushioning member 68 is covered on the outer peripheral surface of the support bracket 58b. I am wearing it.

[Brief description of the drawings]

FIG. 1 is a side view in a free lift state showing a mast portion of a forklift to which a lift chain buffer structure according to the present invention is applied.

FIG. 2 is a side view showing the lowest state of the mast portion of FIG. 1;

FIG. 3 is a side view showing a mast portion of FIG. 1 in a highest state.

FIG. 4 is a top view corresponding to the forklift of FIG. 1;

FIG. 5 is a view of the carriage of FIG. 1 alone viewed from the rear side.

FIG. 6 is an enlarged side view showing a mast part of FIG. 1;

FIG. 7 is a perspective view showing a mounting structure of the tilt cylinder of FIG. 1;

FIG. 8 is an exploded perspective view of the tilt cylinder of FIG. 7;

FIG. 9 is a perspective view showing a mounting structure of another tilt cylinder.

FIG. 10 is an exploded perspective view of the tilt cylinder of FIG. 9;

FIG. 11 is a partial sectional view showing the structure of a conventional forklift.

[Explanation of symbols]

 Reference Signs List 10 outer mast 14 inner mast 20 fork 22 carriage 24, 26 finger bar 40 lift chain 42 sprocket 52 tilt cylinder 56 tilt pin 62, 64, 66, 68 cushioning member

Claims (5)

[Claims] 1. A forklift in which an inner mast is arranged inside an outer mast so as to be able to move up and down inside a vehicle width direction and a carriage for supporting a fork is suspended so as to be able to move up and down. A lift chain buffer structure for a forklift, wherein a buffer member is mounted on an outer surface of the outer mast facing the outer mast. 2. The lift chain is suspended from a sprocket attached to an upper portion of an inner mast, one end of a front side thereof is connected to a carriage, and the other end of a rear side thereof is connected to an outer mast side. The forklift according to claim 1, wherein an outer portion of the cushioning member mounted on the side surface is disposed in a substantially front area with respect to a line connecting one end to the other end of the lift chain when viewed from the side. Lift chain buffer structure. 3. A cylinder portion rotatably fitted to a tilt pin fixed to an outer surface of the outer mast is provided at a tip end of a piston rod of the tilt cylinder for tilting the outer mast. The lift chain buffer structure for a forklift according to claim 1 or 2, wherein a buffer member is provided on the opposing outer peripheral surfaces. 4. A tip end of a piston rod of a tilt cylinder for tilting the outer mast is rotatably connected to a tilt bracket provided on an outer surface of the outer mast, and an outer peripheral surface of the tilt bracket facing the lift chain. The lift chain buffer structure for a forklift according to claim 1 or 2, further comprising a buffer member. 5. A front end of the lift chain is fixed to a lower finger bar of the carriage, and a cushioning member is mounted on an upper finger bar of the carriage opposed to the lift chain. 4
The lift chain buffer structure for a forklift according to any one of the above items.