Title: Forklift
Abstract: A forklift has a travelling carriage, a straddle arm disposed on the travelling carriage, a mast disposed on the straddle arm to be reciprocally movable in a horizontal direction, a fork disposed on the mast to be movable up and down, and a cover disposed on the travelling carriage. When the mast is in a reach-in operation, the cover covers at least an upper side of an article supported by the fork.
Patent Number: 6,877,945 Issued on 04/12/2005 to Ando, et al.
| Inventors:
|
Ando; Hideki (Shiga, JP);
Wada; Toshio (Shiga, JP);
Fujikawa; Kazuhiro (Shiga, JP);
Moriyama; Tomohiro (Shiga, JP)
|
| Assignee:
|
Nippon Yusoki Co., Ltd. (Kyoto, JP)
|
| Appl. No.:
|
152676 |
| Filed:
|
May 23, 2002 |
Foreign Application Priority Data
| May 25, 2001[JP] | P. 2001-156220 |
| Current U.S. Class: |
414/631; 414/659; 414/662 |
| Intern'l Class: |
B65G 001//00 |
| Field of Search: |
414/631,630,659,661,662,663,664,673,718
296/186.3,186.4
|
References Cited [Referenced By]
U.S. Patent Documents
| 3202232 | Aug., 1965 | Rogers | 180/119.
|
| 3521780 | Jul., 1970 | Cook | 414/632.
|
| 4411582 | Oct., 1983 | Nakada | 414/636.
|
| 4998858 | Mar., 1991 | Magens | 414/495.
|
| 6064629 | May., 2000 | Stringer et al. | 367/128.
|
| 6168367 | Jan., 2001 | Robinson | 414/539.
|
| 6269913 | Aug., 2001 | Kollmannsberger et al. | 187/394.
|
| Foreign Patent Documents |
| 200 18 547 | Mar., 2001 | DE.
| |
| 199 58 086 | Jun., 2001 | DE.
| |
| 0 116 152 | Aug., 1984 | EP.
| |
| 766292 | Jan., 1957 | GB.
| |
| 2 118 521 | Nov., 1983 | GB.
| |
| 8-143291 | Jun., 1996 | JP.
| |
Other References
Patent Abstracts of Japan: vol. 2002, No. 03, Apr. 3, 2002 JP 2001-322479
A: Nov. 20, 2001.
|
Primary Examiner: Lowe; M. Scott
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
What is claimed is:
1. A forklift comprising:
a travelling carriage;
a straddle arm disposed on the travelling carriage;
a mast disposed on the straddle arm to be reciprocally movable in a
horizontal direction;
a fork disposed on the mast to be movable up and down; and
a cover disposed on the travelling carriage, wherein when the mast is in a
reach-in operation, the cover covers at least an upper side of an article
supported by the fork,
further comprising a shutter,
wherein the cover is fixed to the straddle arm;
wherein the cover is formed into a box-shape to cover the upper, front,
rear, right, and left sides of the article, wherein the cover defines an
opening portion through which the article is taken in or out; and
wherein the shutter closes or opens the opening portion.
2. The forklift according to claim 1, wherein the cover has a height to
allow the mast to pass through the cover when the mast is in the reach-in
operation.
3. The forklift according to claim 1, wherein the cover has a length in the
horizontal direction so that when the mast is in a maximum reach-out
state, the fork is positioned outside the cover.
4. The forklift according to claim 3, further comprising a position sensor
for detecting a position of the mast in the horizontal direction, wherein
when it is detected on the basis of a detection signal from the position
sensor that at least one of the mast and the fork is positioned inside the
cover, the fork is inhibited from being lifted and lowered outside a
predetermined range.
5. The forklift according to claim 4, wherein when the inhibiting operation
is conducted, an alarm is given.
6. The forklift according to claim 4, wherein notification of cancellation
of the inhibiting operation is given.
7. The forklift according to claim 3, further comprising a position sensor
for detecting a lifted position of the fork, wherein when it is detected
on the basis of a detection signal from the position sensor that the
lifted position of the fork is higher than a predetermined level, the mast
is inhibited from performing the reach-in operation.
8. The forklift according to claim 1, wherein the mast has:
an outer mast moving along the straddle arm; and
an inner mast lifting and lowering along the outer mast, and wherein the
cover has a length in the horizontal direction so that when the mast is in
a maximum reach-out state, the inner mast is positioned outside the cover.
9. The forklift according to claim 1, wherein when the shutter opens the
opening portion, the shutter is accommodated in the cover.
10. The forklift according to claim 1, wherein a window for interior
inspection is defined at a side face of the cover.
11. The forklift according to claim 1, further comprising a door through
which an operator enters and exits at a side face of the cover.
12. The forklift according to claim 1, further comprising an article sensor
for detecting a height and width of an article on the fork to detect
whether or not the article is accommodatable, the article sensor disposed
at the opening portion of the cover, wherein when the article sensor
detects that the article is not accommodatable, the mast is inhibited from
performing the reach-in operation.
13. The forklift according to claim 1, further comprising an end sensor for
detecting a rear end of an article to be accommodated in the horizontal
direction inside the opening, wherein when the end sensor detects the rear
end of the accommodated article, the shutter is inhibited from closing.
14. The forklift according to claim 1, further comprising a restraining
member for restraining an unnecessary motion of the accommodated article
in the cover.
15. The forklift according to claim 14, wherein the restraining member is
positioned above the most-lowered position of the fork and on both sides
of a lifting region of the fork; and
wherein the restraining member has an article support surface which
supports the article supported on the fork from a lower side of the fork,
when the fork lowers.
Description
The present disclosure relates to the subject matter contained in Japanese
Patent Application No. 2001-156220 filed May 25, 2001, which is
incorporated herein by reference its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a forklift which takes an article therein,
transports the article to a predetermined position, and carries the
article in the predetermined position.
2. Description of the Related Art
A forklift of this kind is configured so as to have a mast disposed on a
travelling carriage in a horizontally reciprocally movable manner, and a
fork liftably disposed on the mast. In the forklift, the mast is moved
toward an end of the travelling carriage to cause the forks to be
projected from the travelling carriage (this motion of the mast is called
"reach-out"), whereby the forks are inserted below an article which is to
be accommodated. Thereafter, the forks are lifted by the mast to raise the
article, and the mast is then moved inside the travelling carriage (this
motion of the mast is called "reach-in"), whereby the article is
accommodated on the travelling carriage. After the travelling carriage
travels to a predetermined position, the mast performs a reach-out process
to push out the forks together with the article to the outside of the
travelling carriage. The forks are then lowered to place the article in
the predetermined position.
In such a forklift according to the related art, a surface of the article
in the accommodated condition is exposed, and hence there arises a problem
in that the article is inevitable to contact with a foreign material. In a
forklift used outdoors, particularly, an article is wet in case of rain or
the like.
The invention has been conducted in view of the problem of the conventional
art. It is an object of the invention to provide a forklift which can
transport an accommodated article while preventing the article from
contacting a foreign material.
SUMMARY OF THE INVENTION
In order to attain the object, according to a first aspect of the
invention, there is provided a forklift having:
a travelling carriage;
a straddle arm disposed on the travelling carriage;
a mast disposed on the straddle arm to be reciprocally movable in a
horizontal direction;
a fork disposed on the mast to be movable up and down; and
a cover disposed on the travelling carriage,
wherein when the mast is in a reach-in operation, the cover covers at least
an upper side of an article supported by the fork.
According to a second aspect of the invention, there is provided the
forklift according to the first aspect, in which the cover has a height to
allow the mast to pass through the cover when the mast is in the reach-in
operation.
According to a third aspect of the invention, there is provided the
forklift according to any one of the first and second aspects, in which
the cover has a length in the horizontal direction so that when the mast
is in a maximum reach-out state, the fork is positioned outside the cover.
According to a fourth aspect of the invention, there is provided the
forklift according to any one of the first and second aspects, wherein the
mast has:
an outer mast moving along the straddle arm; and
an inner mast lifting and lowering along the outer mast, and
wherein the cover has a length in the horizontal direction so that when the
mast is in a maximum reach-out state, the inner mast is positioned outside
the cover.
According to a fifth aspect of the invention, there is provided the
forklift according to any one of the third and fourth aspects, further
having a position sensor for detecting a position of the mast in the
horizontal direction,
wherein when it is detected on the basis of a detection signal from the
position sensor that at least one of the mast and the fork is positioned
inside the cover, the fork is inhibited from being lifted and lowered
outside a predetermined range.
According to a sixth aspect of the invention, there is provided the
forklift according to any one of the third to fifth aspects, further
having a position sensor for detecting a lifted position of the fork,
wherein when it is detected on the basis of a detection signal from the
position sensor that the lifted position of the fork is higher than a
predetermined level, the mast is inhibited from performing the reach-in
operation.
According to a seventh aspect of the invention, there is provided the
forklift according to any one of the first to sixth aspects, further
having a shutter,
wherein the cover is fixed to the straddle arm;
wherein the cover is formed into a box-like shape to cover the upper,
front, rear, right, and left sides of the article,
wherein the cover defines an opening portion through which the article is
taken in/out; and
wherein the shutter closes/opens the opening portion.
According to a eighth aspect of the invention, there is provided the
forklift according to the seventh aspect, wherein when the shutter opens
the opening portion, the shutter is accommodated in the cover.
According to a ninth aspect of the invention, there is provided the
forklift according to any one of the seventh and eighth aspects, wherein a
window for interior inspection is defined at a side face of the cover.
According to a tenth aspect of the invention, there is provided the
forklift according to any one of the seventh to ninth aspects, further
having a door through which an operator enters and exits at a side face of
the cover.
According to an eleventh aspect of the invention, there is provided the
forklift according to any one of the seventh to tenth aspects, further
having an article sensor for detecting a height and width of an article on
the fork to detect whether or not the article is accommodatable, the
article sensor disposed at the opening portion of the cover,
wherein when the article sensor detects that the article is not
accommodatable, the mast is inhibited from performing the reach-in
operation.
According to a twelfth aspect of the invention, there is provided the
forklift according to any one of the seventh to eleventh aspects, further
having an end sensor for detecting a rear end of an article to be
accommodated in the horizontal direction inside the opening, wherein when
the end sensor detects the rear end of the accommodated article, the
shutter is inhibited from closing.
According to a thirteenth aspect of the invention, there is provided the
forklift according to any one of the fifth, sixth, eleventh, twelfth
aspects, wherein when the inhibiting operation is conducted, an alarm is
given.
According to a fourteenth aspect of the invention, there is provided the
forklift according to any one of the fifth, sixth, eleventh and twelfth
aspects, wherein notification of cancellation of the inhibiting operation
is given.
According to a fifteenth aspect of the invention, there is provided the
forklift according to any one of the first to fourteenth aspects, further
having a restraining member for restraining an unnecessary motion of the
accommodated article in the cover.
According to a sixteenth aspect of the invention, there is provided the
forklift according to the fifteenth aspect,
wherein the restraining member is positioned above the most-lowered
position of the fork and on both sides of a lifting region of the fork;
and
wherein the restraining member has an article support surface which
supports the article supported on the fork from a lower side of the fork,
when the fork lowers.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments are described below based on the drawings, in which
like numerals represent like parts, and wherein:
FIG. 1 is a side view showing an embodiment of the invention;
FIG. 2 is a plan view showing the embodiment of the invention;
FIG. 3 is an enlarged side view showing main portions of the embodiment of
the invention;
FIG. 4 is an enlarged longitudinal section view showing a base driving
mechanism in the embodiment of the invention;
FIG. 5 is an enlarged plan view showing a position sensor of a mast in the
embodiment of the invention;
FIG. 6 is a front view showing the embodiment of the invention;
FIG. 7 is a partially omitted side view showing the embodiment of the
invention;
FIG. 8 is an enlarged side view showing main portions of the position
sensor of the mast in the embodiment of the invention;
FIG. 9 is a partially omitted plan view showing the embodiment of the
invention;
FIG. 10 is a partially omitted side view showing the embodiment of the
invention;
FIG. 11 is an enlarged longitudinal section view showing a charging
connector in the embodiment of the invention;
FIG. 12 is an enlarged cross section view showing the charging connector in
the embodiment of the invention;
FIG. 13 is an enlarged side view showing the charging connector in the
embodiment of the invention;
FIG. 14 is an enlarged longitudinal section view illustrating the function
of the charging connector in the embodiment of the invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, an embodiment of the invention will be described with
reference to the accompanying drawings.
In FIGS. 1 and 2, a reference numeral 1 denotes a forklift of the
embodiment. In the embodiment, the forklift is an unmanned forklift, which
travels outdoors to transport an article W.
A forklift has a basic configuration including a travelling carriage 2, a
straddle arm 3 disposed on the travelling carriage 2 along a horizontal
direction, a mast 4 disposed on the straddle arm 3 to be reciprocally
movable in the horizontal direction, a fork 5 disposed on the mast 4 to be
movable up and down, and a cover 6 disposed on the travelling carriage 2.
When the mast 4 is in a reach-in operation (the reach-in operation is an
operation in which the mast 4 moves toward the inside of the traveling
carriage 2), the cover 6 covers at least an upper side of an article W,
which is an article supported by the fork 5.
The configuration will be described in detail. Running wheels 7 are
disposed below a front side (the right side in FIG. 1 where the article W
is taken in/out) of the travelling carriage 2, and a steering wheel 8
which controls the traveling direction, and which serves also as a driving
wheel is disposed below the rear side.
A control device 9 is disposed above the rear side of the travelling
carriage 2. The control device has functions of driving and steering the
steering wheel 8, and controls the functions and driving of the mast 4 and
the forks 5. A secondary battery (not shown) which serves as a driving
electric power source is disposed in the control device 9.
As shown in FIG. 4, the straddle arms 3 are formed to have a U-like section
shape, and attached to the travelling carriage 2 so that their openings
are opposed to each other.
A slide base 10 onto which the mast 4 is attached is movably mounted
between the straddle arms 3. In the slide base 10, as shown in FIG. 4,
running rollers 11 which are rollably fitted into the straddle arms 3 are
rotatably attached to the both sides. A pair of the running rollers 11 are
disposed in each of the straddle arms 3 with being separated from each
other in the length direction of the straddle arms.
Racks 12 are attached integrally to the upper sides of the straddle arms 3
over a substantially whole length of the straddle arms, respectively. A
base driving mechanism 13 which moves the slide base 10 is engaged with
the racks 12.
As shown in FIG. 4, the base driving mechanism 13 is configured by: a pair
of pinions 14 which mesh with the racks 12; a driving shaft 16 in which
the pinions 14 are attached coaxially integrally to the both ends,
respectively, and which is rotatably supported on the slide base 10 by a
pair of brackets 15; a gear box 17 which is disposed in an intermediate
portion in the length direction of the driving shaft 16; and a motor 18
which is mounted on the gear box 17 to rotate the driving shaft 16 in the
forward and reverse directions via the gear box 17.
In the embodiment, as shown in FIG. 5, the mast 4 is configured by: a pair
of outer masts 19 which upstand integrally from the slide base 10 with
being separated from each other in the width direction of the slide base
10; a pair of inner masts 21 which are liftably mounted on the insides of
the outer masts 19 via guide rollers 20; and a cylinder 22 which upstands
from the slide base 10, and which is coupled to the inner masts 21 via
pulling cables such as chains. The forks 5 are attached integrally to the
inner masts 21. The inner masts 21 are lifted or lowered by the cylinder
22, so that the forks 5 attached to the inner masts 21 are lifted or
lowered.
By contrast, as shown in FIGS. 1, 2, and 6, the cover 6 is formed into a
box-like shape, and fixed integrally to upper portions of the straddle
arms 3. An opening 23 is formed in the front face of the cover 6 so that,
when the mast 4 is moved in the projection direction (this motion of the
mast 4 is called reach-out), the forks 5, and the article W which is
supported by the forks 5 are taken in/out through the opening 23.
As shown in FIG. 6, the opening 23 is formed so as to be higher than the
height of the mast 4 in the reach-in process, or to be higher than the
height of the article W which is supported by the forks 5 in the reach-in
process, and to be wider than the width of the article W.
As shown in FIG. 6, a portal guard 24 is attached integrally to the front
end face of the cover 6 so as to elongate along the side edge of the
opening 23.
Article sensors 25 for detecting whether or not the height and width of the
article W accommodated by the forks 5 exceed predetermined dimensions are
disposed on the guard 24. For example, optical sensors are used as the
article sensors 25. The optical sensors are placed inside the guard 24 and
in the vicinity of the both sides of the upper end of the opening 23. The
optical sensors emit a horizontal detection light beam corresponding to
the limit height, and a pair of vertical detection light beams, which are
separated from each other by a distance corresponding to the limit width.
When one of these detection light beams is interrupted, it is judged that
the article W exceeds the predetermined dimensions. When the optical
sensors are of the reflection type, the above-mentioned judgment can be
performed on the basis of existence of reflected light beams. A detection
signal from the article sensors 25 is used for inhibiting the reach-in
operation of the mast 4 when the shape of the article W is larger than an
allowable shape.
The length of the cover 6 in the movement direction of the mast 4 (i.e.,
the reach direction) is set so that when the mast 4 is in the maximum
reach-out state, the inner masts 21 are positioned outside the cover as
shown in FIG. 3.
In the embodiment, a position sensor 26 which detects the position of the
mast 4 in the reach direction is disposed on the straddle arms 3. As shown
in FIG. 7, the position sensor 26 includes a reach-in sensor 27, a
reach-out sensor 28, and intermediate position sensors 29. The reach-in
sensor 27 is disposed in the vicinity of the inner ends of the straddle
arms 3 to detect the most reach-in position of the mast 4 (the most
reach-in position is a position on the forklift, which the most far from
the front side of the traveling carriage 2 and the mast 4 can move to).
The reach-out sensor 28 is disposed in the vicinity of the front ends of
the straddle arms 3 to detect the most reach-out position of the mast 4
(the most reach-out position is a position outside the cover 6, which the
most far from the cover 6 and the mast 4 can move to). The plurality of
intermediate position sensors 29 are disposed at predetermined intervals
between the reach-in sensor 27 and the reach-out sensor 28.
The reach-in sensor 27 or the reach-out sensor 28 is formed so that, at the
timing when the mast 4 reaches the vicinity of the most reach-in position
or the most reach-out position, the movement speed of the mast 4 is
reduced, and the mast is then stopped at the most reach-in position or the
most reach-out position. In accordance with detection signals of the
intermediate position sensors 29, the mast 4 is moved at a normal speed
between the most reach-in position and the most reach-out position.
When the mast 4 is detected by the reach-in sensor 27 to detect that the
forks 5 are positioned inside the cover, the forks 5 are inhibited from
being lifted or lowered outside a predetermined range.
As shown in FIGS. 5 and 8, a position sensor 30 for detecting a lifted
position of the forks 5 is disposed between the slide base 10 and the
inner mast 21.
The position sensor 30 includes a reel 32 having a pulse counter 31, a wire
33 wound around the reel 32 and pulled out from the reel 32 to be fixed to
the inner mast 21, and a pulley 34 attached to the slide base 10 to guide
the wire 33.
The wire 33 is always pulled in the winding direction by a spring
incorporated in the reel 32 to be held in a state of tension. The wire is
pulled out from the reel 32 in accordance with lifting of the inner mast
21 and wound around the reel 32 in accordance with lowering of the inner
mast 21.
The lifted distance of the inner mast 21 is equal to the pulled-out length
of the wire 33. When the pulled-out length of the wire 33, i.e., the
rotational amount of the reel 32 is detected by the pulse counter 31, the
lifted distance of the inner mast 21 can be calculated.
When it is detected on the basis of a detection signal from the position
sensor 30 that the lifted position of the forks 5 is higher than a
predetermined level, the reach-in operation of the mast 4 is inhibited.
In the embodiment, a shutter 35 which closes and opens the opening 23 is
disposed in the cover 6.
The shutter 35 is configured by sequentially connecting long sides of many
rectangular plates by hinges in a swingable manner. The both short sides
of the plates are slidably fitted into guide grooves 36 which are formed
in the inner side face of the cover 6, so that the shutter is mounted on
the cover 6.
As shown in FIG. 1, each of the guide grooves 36 is configured by a
vertical portion 36a which elongates along the opening 23 and a horizontal
portion 36b which elongates along the ceiling of the cover 6. A connecting
portion between the vertical portion 36a and the horizontal portion 36b is
arcuately formed to enable the shutter 35 to move between the vertical
portion 36a and the horizontal portion 36b. When the shutter 35 is
positioned in the vertical portion 36a, the opening 23 is closed, and when
the shutter 35 is moved into the horizontal portion 36b, the shutter is
accommodated in the cover 6 and the opening 23 is opened.
As shown in FIGS. 1 and 9, a driving mechanism 37 which moves the shutter
35 along the guide grooves 36 is disposed in the ceiling portion of the
cover 6 and the position which is below the movement locus of the shutter
35.
The driving mechanism 37 is configured by: a sprocket 38 which is rotatably
mounted in the vicinity of the opening 23; a geared motor 39 which is
mounted with being separated from the sprocket 38 in the accommodating
direction of the shutter 35; and an endless belt 40 such as a chain which
is wound between the sprocket 38 and the geared motor 39. An upper end
portion of the shutter 35 is coupled to an intermediate portion of the
endless belt 40 via a coupling member 41.
As shown in FIGS. 9 and 10, restraining members 42 which restrain an
unnecessary motion of the accommodated article W are mounted via a
plurality of brackets 43 in portions which are above the straddle arms 3
and inside the cover 6.
The restraining members 42 are positioned above the most-lowered position
of the forks 5 as shown in FIG. 10, and on the both sides of the lifting
region of the forks 5 as shown in FIG. 9.
In each of the restraining members 42, as shown in FIGS. 4 and 9, an
article support face 42a which supports the article W from the lower side
is formed, and a side support face 42b is formed so as to upward extend
from the side of the article support face 42a which is on the outer side
of the forklift 1. The side support faces 42b are formed so that their
upper portions are inclined toward the outer sides, thereby guiding the
article W, which is to be placed on the restraining members 42, toward the
article support faces 42a.
In the restraining members 42, stoppers 44 are disposed in end portions of
the article support faces 42a on the side of the opening 23, respectively.
The article W which is placed on the article support faces 42a is engaged
with the stoppers 44, thereby restraining movement of the article W toward
the opening 23.
On the other hand, in the embodiment, a connector 45 is disposed in a side
portion of the control device 9 as shown in FIGS. 2 and 9. A charging arm
for charging the secondary battery mounted in the control device is to be
connected to the connector.
Specifically, as shown in FIG. 11, the charging arm 46 disposed in a
charging terminal or the like is to be inserted into the connector 45 to
be electrically connected thereto. The connector 45 is attached to the
main section 47 of the control device 9, and comprises a charging shoe 48
to which the charging arm 46 is electrically connected, and a box-like
cover 49 which covers the periphery of the charging shoe 48.
In the cover 49, an insertion port 50 for the charging arm 46 is disposed
in a side portion, and a pair of doors 51 which close and open the
insertion port 50 are swingably disposed inside the cover 49.
The doors 51 are openably supported on the inner face of the cover 49 by a
plurality of hinges 52 which are disposed in the vicinity of the both
sides of the insertion port 50, so as to be opened toward the inner sides
of the cover 49 in a bipartite manner. Springs which urge the doors 51 in
a closing direction are incorporated in the hinges 52, so that the doors
51 are normally held by the springs to the respective closing positions.
As shown in FIG. 11, the bottom face of the cover 49 is inclined so that
the inner side is higher in level, and the lower end of the bottom face is
continuous to the lower end edge of the insertion port 50. A gap G of a
predetermined height is formed between the lower end of each of the doors
51 and the lower end edge of the insertion port 50, so that water drops or
the like which enter inside the cover 49 are guided by the inclination of
the bottom face of the cover 49 to the lower end edge of the insertion
port 50 to be discharged to the outside through the gap G.
In the embodiment, as shown in FIG. 13, many vertical grooves 53 are formed
in the outer faces of the doors 51. The vertical grooves 53 are disposed
in order to, when water drops or the like adhere to the outer faces of the
doors 51, quickly guide the water drops or the like to a lower side.
In the charging arm 46 shown in the embodiment, protection plates 54 and 55
which are projected to the front side are disposed above and below the end
portion on the insertion side, respectively. The protection plates 54 and
55 are projected more than end faces of electrodes 56 disposed at the tip
end of the charging arm 46. When the charging arm 46 is to be inserted
into the cover 49, the protection plates are in contact with the doors 51
in advance of the electrodes 56, and push the doors 51 open, thereby
preventing the electrodes 56 from contacting the doors 51.
The tip end portions of the protection plates 54 and 55 are formed into an
arcuate shape in a plan view, so that the above-mentioned operation of
pushing the doors 51 open can be smoothly conducted. The tip end of the
protection plate 55 which is positioned in the lower side is more forward
projected than that of the protection plate 54 which is positioned in the
upper side.
This configuration is employed in order to, when the doors 51 to which
water drops or the like adhere are to be opened, cause the doors to be
first in contact with the lower protection plate 55, and catch the water
drops or the like by a portion below the electrodes 56, thereby preventing
the water drops or the like from dropping on the electrodes 56.
In FIG. 1, reference numeral 57 denotes windows for interior inspection,
which are formed in a side face of the cover 6.
As shown in FIG. 10, the thus configured forklift 1 of the embodiment is
moved to an article carrying-in station A to conduct an operation of
loading the article W in the article carrying-in station A.
When the forklift is moved in this way to the article carrying-in station
A, first, the shutter 35 is pulled up by the driving mechanism 37 toward
the ceiling portion of the cover 6 to be accommodated therein, and the
opening 23 of the cover 6 is largely opened. As a result, the forks 5 are
stopped at a position opposed to a gap below the article W.
Then, the base driving mechanism 13 is actuated to start the reach-out
operation. When the mast 4 is detected by the reach-out sensor 28, the
reach-out operation is stopped. In the stopped state, the forks 5 are
inserted below the article W which is positioned in the article
carrying-in station A.
The inner masts 21 constituting the mast 4 are raised by the cylinder 22.
In accordance with this raising, the article W is lifted by the forks 5.
When the lifted distance of the article W becomes equal to a predetermined
distance, the operation of raising the forks 5 is stopped. The stopping
position of the forks 5 is controlled on the basis of the detection signal
from the position sensor 30.
When the lifting of the article W is completed in this way, the base
driving mechanism 13 is again actuated to start the reach-in operation,
and the mast 4 and the forks 5 are moved toward the interior of the cover
6, thereby starting the operation of accommodating the article W. In the
case where the lifted position of the forks 5 is higher than a
predetermined height, even if the lifted article W has a size which allows
the article to be accommodated, it is assumed that the upper end of the
article is positioned in a level which is higher than the upper end of the
opening 23. In this case, therefore, the reach-in operation is not
conducted. In the case where the lifted position of the forks 5 is
adequate, the reach-in operation is started. When the article W is then
pulled into the guard 24 surrounding the opening 23, the height and width
of the article W are measured by the article sensors 25 disposed on the
guard 24. If it is judged that the size of the article W exceeds the
predetermined shape, the reach-in operation of the forks 5 is stopped, and
notification is made by an alarm or the like.
On the other hand, if it is judged that the size of the article W is not
larger than the predetermined shape, the reach-in operation is
continuously conducted. When the mast 4 is pulled into a predetermined
position in the cover 6, the position of the mast 4 is detected by the
intermediate position sensors 29, with the result that the movement speed
of the slide base 10 is increased so that high-speed movement is
conducted. At the timing when the mast reaches the vicinity of the most
reach-in position, the mast is stopped at the most reach-in position while
being decelerated on the basis of the detection signal from the reach-in
sensor 27.
When a rear end portion of the accommodated article W in the accommodating
direction is detected by, for example, the article sensors 25, it is
judged that the article W is not completely accommodated in the cover 6.
Then, notification is made by an alarm or the like, and the driving
mechanism 37 is not actuated, so that the shutter 35 is held to the opened
state. Alternatively, the detection of a rear end portion of the
accommodated article W may be performed by separately disposing a
rear-portion sensor inside the cover 6 and in the vicinity of the opening.
If it is judged that the article W is completely accommodated in the cover
6, the driving mechanism 37 is actuated to move the shutter 35 toward the
opening 23 to close the opening 23.
In a state where the article W is completely accommodated in the cover 6
and the forks 5 are positioned in the cover 6, the lifting range of the
forks 5 is limited. This process is conducted because of the following
reason. When the forks 5 are lifted by a degree which is more than
necessary, there is a possibility that an upper portion of the article W
supported by the forks 5 may damage the driving mechanism 37 and the like
which are disposed in an upper portion inside the cover 6. The process is
conducted in order to prevent such a failure from occurring.
The forks 5 are lowered in the range which is limited as described above,
thereby allowing the forks 5 to be lowered with passing between the pair
of the restraining members 42 which are placed in the lower portion of the
cover 6. In the middle of the lowering process, the article W supported by
the forks 5 is supported by the article support faces 42a of the
restraining members 42 to stop the lowering of the article. The operation
of lowering the forks 5 is continued, and stopped at the timing when the
forks are lowered below the restraining members 42.
The lifted position of the forks 5 is detected by the position sensor 30
which is disposed between the slide base 10 and one of the inner masts 21.
By contrast, when the article W is to be placed on the article support
faces 42a of the restraining members 42, the article is guided toward the
article support faces 42a by the inclined faces of the side support faces
42b, so that the article is placed smoothly and surely on the article
support faces 42a. Since the stoppers 44 disposed on the article support
faces 42a are opposed to the end portions on the side of the opening 23,
the article W which is placed on the article support faces 42a is
restrained from being accidentally moved toward the opening 23.
The forklift 1 which accommodates the article W as described above can
transport the article W to a target position in a state where the article
W is surrounded by the cover 6 and the shutter 35. The accommodated
article W can be carried out by conducting the above-mentioned operations
in the reverse sequence. Therefore, there is no possibility that, in the
course of the transportation, the article W is in contact with a foreign
material or gets wet by rain or the like.
In the embodiment, since the inspection windows 57 are disposed in the side
face of the cover 6, the components in the cover 6 can be easily
inspected.
In the embodiment described above, the shapes, dimensions, and the like of
the components are exemplarily shown, and can be variously changed
depending upon design requirements or the like. In the embodiment, for
example, the cover 6 is formed into a box-like shape. Alternatively, the
cover may be formed so as to cover only the upper side of the article W.
When any one of the above-mentioned various inhibiting operations is
cancelled, the cancellation may be notified acoustically or visually by a
sound device or a display device. As shown by reference numeral 58 in FIG.
10, a door through which the operator can enter and exit may be formed in
a side face in the vicinity of the rear end of the cover 6.
As described above, in the forklift according to the first to fourth
aspects of the invention, when the mast is in the reach-in operation, the
cover covers at least an upper side of the article supported by the fork
is disposed on the travelling carriage. Hence, a foreign matter, water
drops, and the like are prevented from adhering to the accommodated
article. Therefore, the soundness of the transported article can be
ensured. When the fork is projected completely outside the cover, an
article can be surely lifted and accommodated.
In the forklift according to the fifth aspect of the invention, when it is
detected that the mast or the fork attached to the mast is positioned
inside the cover, the fork is inhibited from being lifted or lowered
outside a predetermined range. Therefore, the lifting and lowering of the
fork by a degree which is more than necessary can be limited, so that the
fork and the article are prevented from accidentally contacting another
apparatus or the components.
In the forklift according to the sixth aspect of the invention, when it is
detected that the lifted position of the fork is higher than a
predetermined level, the mast is inhibited from performing the reach-in
operation. Therefore, it is possible to prevent the article supported by
the fork from contacting the cover, thereby preventing the article from
being damaged.
In the forklift according to the seventh aspect of the invention, the cover
is fixed to the straddle arm and formed into a box-like shape. The cover
covers the upper, front, rear, right, and left sides of the article. An
opening through which the article is to be taken in/out is formed in a
reach-out direction of the mast. A shutter, which closes and opens the
opening, is disposed. Therefore, an article can be taken in/out through
the opening, and a substantially whole periphery of the accommodated
article is covered, whereby the article can be completely protected from a
foreign material, rain, and the like.
In the forklift according to the eighth aspect of the invention, when the
opening is opened, the shutter is accommodated in the cover. Therefore,
the shutter is prevented from being projected to the outside of the cover,
whereby the forklift can be made compact.
In the forklift according to the ninth and tenth aspects of the invention,
a window for interior inspection is formed in a side face of the cover.
Therefore, interior inspection can be easily conducted.
In the forklift according to the eleventh aspect of the invention, an
article sensor which detects a height and width of an article on the fork
to detect whether or not the article is accommodatable is disposed in the
opening of the cover. When the article sensor detects that the article is
not accommodatable, the mast is inhibited from performing the reach-in
operation. Therefore, an article, which is not accommodatable, is
prevented from being damaged by carelessly conducting an operation of
accommodating the article.
In the forklift according to the twelfth aspect of the invention, an end
sensor for detecting a rear end portion of an article to be accommodated
in an accommodating direction is disposed inside the opening. When the end
sensor detects the rear end portion of the accommodated article, the
shutter is inhibited from performing the closing operation. Therefore, the
shutter is prevented from accidentally contacting the article, whereby the
article can be prevented from being damaged.
In the forklift according to the thirteenth aspect of the invention, when
any one of the above-mentioned various inhibiting operation is conducted,
an alarm is given. Therefore, such a failure can be known surely and
easily, so that development of unmanned operation is enabled.
The forklift according to the fourteenth aspect of the invention is
characterized in that, in any one of the fifth, sixth, eleventh, and
twelfth aspects, notification of cancellation of the inhibiting operation
is given.
In the forklift according to the fifteenth aspect of the invention, a
restraining member for restraining an unnecessary motion of the
accommodated article is disposed in the cover. Therefore, an unnecessary
motion of the article during transportation can be restrained to prevent
the transportation attitude from being broken, so that stable
transportation is enabled and the article can be prevented from being
damaged.
In the forklift according to the sixteenth aspect of the invention, the
restraining member is positioned above the most-lowered position of the
fork and on both sides of a lifting region of the fork. An article support
face which, in accordance with a lowering operation of the fork, supports
the article supported on the fork, from a lower side of the fork is
formed. Therefore, an article, which is introduced by the fork can be
surely placed and accommodated on the restraining member.
*
