GB2358852A

GB2358852A - Fork lift with monitor

Info

Publication number: GB2358852A
Application number: GB0100063A
Authority: GB
Inventors: Tomohiro Moriyama; Midori Nomura
Original assignee: Nippon Yusoki Co Ltd
Current assignee: Nippon Yusoki Co Ltd
Priority date: 2000-01-21
Filing date: 2001-01-03
Publication date: 2001-08-08
Anticipated expiration: 2021-01-03
Also published as: DE10101705A1; FR2804101A1; JP2001206696A; GB0100063D0; GB2358852B; FR2804101B1

Abstract

There is provided a fork lift characterized in that a lift bracket 4 is provided on masts (2, 3) on a body 1 in such a manner as to be raised and/or lowered, that a pair of left and right forks 5 are attached to the lift bracket 4 that a monitor device 12 is provided on the lift bracket 4 for monitoring ahead, and that a monitor 13 is provided on the body 1 for displaying monitored information obtained by the monitoring device 12, wherein a fork positioning mark m is displayed on a display (13a, Fig 4) of the monitor 13.

Description

2358852 FORK LIFT

BACKGROUND OF THE INVENTION Field of Invention

The present invention relates to a fork lift in which the positioning of forks can easily be performed.

2. Description of the Related Art

Fig. 5 shows one example of conventional fork lifts. The fork lift shown is called a reach type fork lift in which a pair of left and right outer masts 2 are displayed at the front of a body 1 so as to be moved in forward and backward directions a and b via wheels 2a, which body comprises driving tires la, caster tires lb and road wheels lc, in which a lift bracket 4 is disposed in such a manner as to be raised and/or lowered a pair of left and right inner masts 3 allowed to be supported on said outer masts 2, respectively, in which a pair of left and right forks 5 are detachably provided on said lift bracket 4 and in which a lift cylinder 6 is provided for raising and/or lowering the pair of forks 5 via the pair of inner masts 3 and the lift bracket 4. Note that reference numeral 7 is a canopy or a head guard.

In the above construction, in performing unloading work for unloading goods W stored in respective storing spaces 8a above respective storing shelves 8 via pallets P, an operator M f irst may enter a cab 9 of the body 1 and then operate a steering 1 - wheel 10a, a selector lever 10b and the like of a driving control part 10 so as to raise and lower the pair of forks 5 to thereby visually position the tips of the pair of forks 5 relative to the predetermined pallet P, thereafter may advance the body 1 as well as the masts 2, 3 so as to allow the pair of forks 5 to be inserted into fork pockets Pa of the pallet P as shown in Fig. 6, then may slightly raise the pair of forks 5 so as to lift the goods W, then may reverse the body 1 and may lower the pair of forks 5. In storing goods W in the respective storing spaces 8a, the above working procedures maybe performed in a reverse fashion.

To be specific in size, for example, the height H of the fork pocket Pa of the pallet P is 10Omm, the thickness L of a root portion of the fork 5 is 50mm, the gradient (x of the fork 5 is 15mm, and upper and lower gaps hl, h2 formed between the fork 5 and the fork pocket Pa when the former is inserted into the latter are 17.5mm.

In the conventional construction as described above, the tips of the pair of forks 5 are relatively far away from the cab 9, and the masts 2, 3 disturb and narrow the field of view. Additionally, in many cases, the tips of the pair of forks 5 are viewed up diagonally from the rear, and moreover, the upper and lower gaps hl, h2 f ormed between the f ork and the f ork pocket Pa when the former is inserted into the latter are small. Thus, in a case where goods W stored within the uppermost storing space 8a. are tried to be unloaded via the pallet P (refer to what is shown by imaginary lines in Fig. 5), it takes much time to position the tips of the pair of forks 5 relative to the pallet P, and this deteriorates the working efficiency.

SUMMARY OF THE INVENTION

The present invention was made in view of the above drawback, and an object thereof is to provide a fork lift in which the positioning of forks can easily be performed.

With a view to attaining the aforesaid object, according to a first aspect of the invention, there is provided a fork lift characterized in that a lift bracket is provided on masts on a body in such a manner as to be raised and/or lowered, that a pair of left and right forks are attached to the lift bracket, that a monitor device is provided on the lift bracket for monitoring ahead, and that a monitor is provided on the body f or displaying monitored inf ormation obtained by the monitoring device, wherein a f ork positioning mark is displayed on a display of the monitor.

According to the above construction, since the fork positioning mark is displayed on the display of the monitor for displaying the monitored information, the tips of the pair of forks can easily be positioned, for example, relative to the pallet P using the mark as a reference.

According to a second aspect of the invention, there is 3 provided a fork lift as set forth in the first aspect above, wherein the fork positioning mark comprises an axis of ordinate passing through a substantially central portion between the pair of forks displayed on the display of the monitor.

According to the above construction, the positioning in transverse directions of the pair of forks can easily be performed using as a reference the axis of ordinate passing through the substantially central portion between the pair of forks displayed on the display of the monitor.

According to a third aspect of the invention, there is provided a f ork lif t as set f orth in the f irst or second aspect of the invention, wherein the fork positioning mark comprises an axis of abscissa passing through a position substantially as high as horizontal portions of said pair of forks displayed on the display of the monitor.

According to the above construction, the positioning in vertical directions of the pair of forks can easily be performed using as a reference the axis of abscissa passing through the position substantially as high as the horizontal portions of the pair of forks displayed on the display of the monitor.

According to a fourth aspect of the invention, there is provided a fork lift as set forth in the third aspect of the invention, wherein the axis of abscissa is displayed at a position slightly lower than tipsof thepairof forks displayed on the display of the monitor.

- 4 According to the above construction, since the error produced by the gradient of the pair of forks is rectified by displaying the axis of abscissa at the position slightly lower than the tips of the pair of forks, the tips of the pair of forks can be inserted into the fork pockets of the pallet in an accurate fashion only by aligning the axis of abscissa with, for example, the center of the pallet.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a side view of a fork lift according to one embodiment of the invention.

Fig. 2 is an enlarged front view of the same fork lift.

Fig. 3 is a block diagram showing a controlling function of an image processing section of the same fork lift.

Fig. 4 is a front view of a monitor of the same fork lift.

Fig. 5 is a side view showing a conventional example.

Fig. 6 is a longitudinal sectional view showing a state in which a fork is inserted into a pallet.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Figs. 1 and 2 show one embodiment of the invention, in which a monitoring device 12 for monitoring ahead is provided on a lift bracket 4, and a monitor 13 is provided on a canopy or a head guard 7 in such a manner as to be oriented toward the inside of a cab 9 for displaying monitored information obtained by the monitoring device 12. The construction of the embodiment other than those remains substantially the same as that of the conventional example shown in Fig. 5, and therefore the description thereof will be omitted by imparting like reference numerals to like portions.

The monitoring device 12 comprises an electronic camera comprising in turn a CCD image sensor, and since it is small in size and light in weight, the electronic camera is attached to the lift bracket 4.

Additionally, the spaces D between the monitoring device 12 and the pair of forks 5 are set substantially equal to each other, whereby the monitoring device 12 is provided at a substantially central portion between the pair of forks 5, thereby making it possible to facilitate the positioning of the pair of forks 5 in lateral directions.

Moreover, the monitoring device 12 is provided on an imaginary horizontal line 0 connecting horizontal portions 5a of the pair of forks 5, thereby making it possible to facilitate the positioning of the pair of forks 5 in vertical directions.

As shown in Fig. 2, a laser transmitter 14 is provided on the lift bracket 4 in such a manner as to face downwardly, and a laser receiver 15 is provided on a cross member provided so as to extend between lower end portions of the outer masts 2 in such a manner as to face upwardly to the laser transmitter 14, whereby monitored information is constructed so as to be 6 - transmitted from the transmitter 14 to the receiver 15. This allows the transmission of monitored information irrespective of the vertical position of the lift bracket 4, and there is needed no communication cable for transmission of monitored information, whereby the construction can be made simple, thereby making it possible to reduce the production cost.

Fig. 3 shows a controlling function that is carried out by an image processing section 16 comprising a micro computer, which image processing section 16 is constructed so as to receive monitored information taken by the monitoring device 12 via the transmitter 14 and the receiver 15 for image processing and display the image processed monitored information on the monitor 13.

As shown in Fig. 4, the monitor 13 has a liquid crystal display 13a, on which images in front of the lift bracket 4 including the horizontal portions 5a. of the pair of forks 5 are displayed, as well as a crosslike fork positioning mark M.

The mark m comprises an axis of ordinate ml which passes through a substantially central portion between the pair of forks 5 displayed on the display 13a and an axis of abscissa m2 which passes through a position substantially as high as the horizontal portions 5a of the pair of forks 5, whereby the position of the pair of forks 5 in the transverse directions e, f can easily be performed using the axis of ordinate ml as 7 a reference, while the positioning of the pair of forks 5 in the vertical directions c, d can easily be performed using the axis of abscissa m2 as a reference.

Here, in order to allow the pair of forks 5 to become horizontal when goods W are lifted with pair of forks 5, the pair of forks 5 are inclined upwardly with a predetermined gradient a (refer to Fig. 6) in an unloaded state. Thus, in a case where the axis of abscissa m2 is displayed as high as the tips of the pair of forks 5, when the tips of the pair of forks 5 are inserted into the fork pockets Pa of the pallet P with the axis of abscissa m2 being aligned with the center of the pallet P, there is caused a risk of the bottoms of the pair of forks 5 coming into contact the bottom plate portion of the pallet P.

To cope with this, in this embodiment, the axis of abscissa m2 is displayed at a position slightly lower than the tips of the pair of forks 5 providing a predetermined space P therebetween to thereby rectify the error that is produced by the gradient a of the pair of forks 5, whereby when the tips of the pair of forks 5 are tried to be inserted into the fork pockets Pa of the pallet P with the axis of abscissa m2 being aligned with the center of the pallet P, the tips of the pair of forks 5 can be inserted into the fork pockets Pa of the pallet P with accuracy without a risk of the pair of forks 5 being brought into contact with the top and bottom plate portions 8 of the pallet P.

As a means for displaying the mark m, it can be conceived that the mark m is directly applied to the lens of the monitoring device 12 or the display 13a of the monitor 13 using a f luorescent paint or that the mark m can be displayed on the display 13a of the monitor 13 by performing image processing at the image processing section 16.

In the above construction, in performing unloading work for unloading goods W stored in the respective storing spaces 8a above the respective storing shelves 8 via the pallets P, an operator M first enters a cab 9 of a body 1 and operates a steering wheel 10a, a selector lever 10b and the like of a driving control part 10 to thereby raise and lower the pair of forks 5. Then, as shown in Fig. 4, while viewing the monitor 13, the operator M positions the mark m so as to align it with the center of the pallet P. In this case, even if it is dark around the pallet P, producing the difficulty in identifying the positions of the tips of the pair of forks 5, it is possible to position the tips of the pair of forks 5 relative to the fork pockets Pa of the pallet P with accuracy.

Thereafter, the pair of forks 5 are inserted into the fork pockets Pa of the pallet P (refer to Fig. 6) by allowing both the pairs of masts 2, 3 to be advanced a while the body 1 is also advanced a, and then after the pair of forks 5 are slightly raised to lift the goods W, the body 1 is reversed 9 - and then the pair of forks 5 may be lowered. In a case where goods W are stored in the respective storing spaces 8a, the working procedures described above maybe followed in a reverse fashion.

According to the above construction, since the fork positioning mark m is displayed on thedisplay13a of themonitor 13 for displaying monitored information, the tips of the pair of forks 5 can easily be positioned relative to the fork pockets Pa of the pallet P using the mark m as a reference.

In the embodiment described heretofore, while the cross-like mark is used as the fork positioning mark, the invention is not limited thereto, and the mark maybe constituted only by the axis of ordinate ml and the axis of abscissa m2, or the mark may be constituted by various types of symbols such as V9. 11, "o" and "[]".

According to the first aspect of the invention, since the fork positioning mark is displayed on the display of the monitor for displaying monitored information, the tips of the pair of forks can easily be positioned relative to the pallet using the mark as a reference.

According to the second aspect of the invention, the positioning of the pair of forks in the transverse directions can easily be performed using as a reference the axis of ordinate which passes through the substantially central portion between the pair of forks displayed on the display of the monitor.

According to the third aspect of the invention, the positioning of the pair of forks in the vertical directions can easily be performed using as a reference the axis of abscissa which passes through the position substantially as high as the horizontal portions of the pair of f orks displayed on the display of the monitor.

According to the fourth aspect of the invention, since the error produced by the gradient of the pair of forks is rectified by allowing the axis of abscissa to be displayed at the position slightly lower than the tips of the pair of forks, the tips of the pair of forks can be inserted into the fork pockets of the pallet with accuracy only by aligning the axis of abscissa with, for example, the center of the pallet.

Claims

CLAIMS:

movablE 1. A fork lift comprising:

main body; mast disposed on the main body; lift bracket provided on the mast, the lift bracket in the vertical direction; pair of lef t and right f orks attached to the lif t bracket; monitor device provided on the lift bracket for monitoring ahead; and a monitor, provided on the main body, for displaying monitored information obtained by the monitoring device, the monitor displays a fork positioning mark on a display of the monitor.
2. The fork lift as set forth in claim 1, wherein the fork positioning mark comprises an axis of ordinate passing through a substantially central portion between the pair of forks displayed on the display of the monitor.
3. The fork lift as set forth in claim 1 or 2, wherein the fork positioning mark comprises an axis of abscissa passing through a position substantially as high as horizontal portions of the pair of forks displayed on the display of said monitor.
4. The fork lift as set forth in claim 3, wherein the 12 axis of abscissa is displayed at a position slightly lower than tips of the pair of forks displayed on said display of said monitor.
5. A fork lift substantially as herein described with reference to any one of Figures 1, 2, 3, 4 and 6 of the accompanying drawings.