[0001] This invention relates to a vacuum held crawler, and more particularly to a crawler
which is adapted to travel on a wall surface of a building or the like by self-propelling
operation or driven otherwise, while being held on the wall surface by vacuum suction,
to thereby permit any working equipment mounted on the crawler to automatically carry
out dangerous operations such as cleaning, painting, maintenance/attendance or the
like of the wall, the building or the like.
[0002] Such a conventional crawler being held on a wall by vacuum suction is disclosed in
the published Japanese Patent Application No. 98595/1978. The crawler includes one
single large-size bowl-like sucker for vacuum suction provided on the peripheral edge
of the bottom side of the crawler with a flange-like seal member of great width which
is outwardly expanded. The crawler is adapted to be suctionally held on a wall by
the sucker. The sucker is equipped with wheels, by means of which the crawler is adapted
to travel on the wall. Thus, in the conventional crawler, a vacuum created in the
large-size sucker causes atmospheric pressure to be exerted to the outside of the
overall flange-like seal member to closely hold the sucker on the wall. Unfortunately,
due to this a frictional resistance between the sucker and the wall is substantially
increased to a degree sufficient to deteriorate the operating efficiency of the crawler
and to substantially increase the demand for driving force required for driving the
apparatus. In addition, the conventional crawler is so constructed that it is held
on the wall by the single large-size sucker by means of vacuum suction. Such a construction
results in that the crawler fails to pass any obstacle such as projections, window
frames or the like on the wall.
[0003] It is an object of the present invention to provide a vacuum held crawler which is
capable of substantially decreasing frictional resistance between the apparatus and
the wall on which it travels. In particular, the crawler should be capable of continuously
and positively traveling on a wall irrespective of any obstacle such as projections
or the like on the wall, while being suctionally held on the wall.
[0004] This object is solved by a crawler according to the main claim. The subclaims characterize
preferred embodiments of the crawler of the invention.
[0005] To summerize some aspects of a preferred embodiment of the crawler, it comprises
a frame on which a working equipment is adapted to be mounted, a vacuum-suction mechanism
mounted on the frame, wheels mounted on the frame and a surface contact mechanism
for receiving the vacuum suction force acting between the crawler and the wall which
surface contact mechanism travels on the wall. The vacuum-suction mechanism includes
a vacuum chamber formed at the bottom thereof, having an opening and being connected
to vacuum generating means, a flexible seal member mounted on the bottom of the vacuum
chamber in a manner as to surround the bottom opening of the vacuum chamber and to
downwardly project by a suitable distance from the bottom of the vacuum chamber. The
surface contact mechanism includes a low friction member having a low friction coefficient
and being mounted on the distal end of the seal member and being in close contact
with the wall.
[0006] Embodiments of the present invention will now be described by reference to the accompanying
drawings, wherein:
Fig. 1 is a vertical sectional view showing an embodiment of a crawler according to
the present invention;
Fig. 2 is a plan view of the crawler shown in Fig. 1;
Fig. 3 is a vertical sectional view showing a seal member and a low friction member
mounted on the seal member which are incorporated in the crawler shown in Fig. 2;
Figs. 4 and 5 each are a bottom view showing a vacuum-suction mechanism which may
be arranged in the crawler of Fig. 2;
Fig. 6 is a plan view showing another embodiment of a crawler according to the present
invention;
Fig. 7 is a side elevation view of the crawler shown in Fig. 6 in use;
Fig. 8 is a vertical sectional front elevation view showing a vacuum-suction mechanism
including wheels and lifting means in the apparatus shown in Fig. 6; and
Fig. 9 is a side elevation view partly in section of the surface suction mechanism
shown in Fig. 8 with the wheels being removed.
[0007] Figs. 1 to 5 illustrate an embodiment of a vacuum held crawler according to the present
invention. The crawler includes a frame 1, on which working equipment S such as cleaning
equipment or the like is adapted to be mounted. The crawler also includes a vacuum-suction
mechanism K and wheels 2 mounted on the frame 1. The vacuum-suction mechanism K includes
a vacuum chamber 4 fixed to the bottom portion of the frame 1 by means of support
members 3 and being connected to suitable vacuum-generating means (not shown), a seal
member 5 fitted to the bottom portion of the vacuum chamber 4 so as to downwardly
project therefrom. A low friction member 6 formed into an annular shape is attached
to the distal end of the seal member 5. The vacuum chamber 4 includes a circular recess
4₂ formed on the bottom of a rectangular or square plate 4₁ so as to open to the outside
or in downward direction. The rectangular plate 4₁ is formed at its central portion
with a small through-hole 4₃ vertically extending between the upper surface of the
plate 4₁ and the recess 4₂. An exhaust pipe 7, which is connected by a hose 8 to the
vacuum-generating means (not shown) such as an air blower, a vacuum pump or the like
is disposed in the through-hole 4₃.
[0008] The seal member 5 is formed of a suitable flexible material such as sponge rubber
or the like-into an annular shape and fitted to the rectangular plate 4₁ so as to
surround the circular recess 4₂. The seal member 5 is arranged so as to vertically
project by a suitable length or distance from the bottom of the plate 4₁ towards a
wall H of a building or the like on which the crawler is to travel. The low friction
member 6 is mounted on the annular distal end of the seal member 5. Such an arrangement
of the low friction member 6 permits the seal member 5 to be in close contact with
the wall H through the low friction member 6. The annular seal member 5 and the low
friction member 6 each have a small thickness, and at the end furface facing the wail
H has a flat shape. The wheels 2 are arranged on both sides of each of the front and
rear portions of the frame 1 and are adapted to be rotatably driven on the wall H
to permit the apparatus to travel thereon.
[0009] In the illustrated embodiment, the positioning of the wheels 2 with respect to the
frame 1 in vertical direction and the length by which the seal member 5 projects from
the plate 4₁ are chosen so that the wheels 2 absorb most of the vacuum suction force
generated in the vacuum chamber 4 during use of the crawler in order to prevent the
vacuum suction force to force the bottom of the vacuum chamber 4 into abuttment against
the wall H during use of the crawler. The traveling of the crawler on the wheels 2
may take place by self-propelling operation which may be effected by connecting one
of the wheels 2 to a drive motor M and the remaining wheels to the drive wheel by
means of a chain or the like as is shown in Fig. 2. Alternatively, the traveling may
be effected by external drive action, for example, by connecting suitable winding-up
means such as a winch or the like to the frame 1 to move the crawler in vertical direction.
[0010] Now, the manner of operation of the crawler will be described.
[0011] The crawler is placed on the wall H and is activated. Then, the vacuum generating
means is activated, so that the vacuum chamber 4 defined by the seal member 5 and
wall H may be evacuated. This causes a pressure drops in the vacuum chamber 4 to a
level below atmospheric pressure, resulting in the seal member 5 being held on the
wall H by the low friction member 6 by vacuum suction, when the crawler travels on
the wall H. During the time, while vacuum suction force is acting on the crawler,
said force is substantially received by the wheels 2 so that the bottom of the vacuum
chamber 4 is prevented from coming into abutment against the wall H. Thus, the crawler
may smoothly travel on the wall while being held on the wall H by the low friction
member 6 by vacuum suction.
[0012] In the illustrated embodiment, one such vacuum-suction mechanism K is arranged on
the frame 1. However, a plurality of such mechanisms may be used, too. Also, a plurality
of recesses 4₂ may be arranged for forming the vacuum chamber 4. Furtheron, the recess
4 and therefore the seal member 5 and the low friction member 6 are formed into a
circular or annular shape. However, they may also have any suitable shape other than
a circular shape such as a square shape or the like. Moreover, the wheels 23 may be
arranged at the vacuum chamber 4 rather than on the frame 1.
[0013] Figs. 6 to 9 show another embodiment of a vacuum held crawler according to the present
invention. In this embodiment, vacuum-suction mechanisms are arranged and mounted
on a frame in a manner different from that described above.
[0014] More particularly, the apparatus of the embodiment includes a frame 11 on which working
equipment S is mounted in a manner to be positioned at the central portion thereof
and a plurality of vacuum-suction mechanisms K are arranged on each of the two sides
of each of the front and rear portions of the frame 11. A plurality of vacuum-suction
mechanisms K arranged in rows in the width or lateral direction of the frame 11 perpendicular
to the longitudinal direction thereof are mounted through support members 13 on the
bottom surface of a common connecting plate 12 arranged so as to extend in the lateral
direction of the frame 11. Two mechanisms K each are mounted together on each of the
connecting plates 12. The crawler also includes a plurality of wheels 2 mounted on
both sides of the connecting plate 12 in the longitudinal direction thereof. On both
sides of each of the front and rear portions of the frame 11 a pair of support beams
14 is arranged in a manner as to be opposite to each other. The connecting plates
12 which are arranged at the front and rear portions of the frame 11 are connected
with both sides thereof to the support beams 14 by air cylinders 15 in a manner as
to be movable in vertical direction or in a direction perpendicular to the wall H.
The air cylinders 15 each may be operated in such a manner that a sensor (not shown)
sensing the passage of the vacuum-suction mechanism K across any obstacle such as
a projection T on the wall H, supplies a detection signal to a control means (not
shown) which is operatively connected to the air cylinder 15, to thereby actuate the
control means. The positioning of the wheels 2 with respect to the connecting plates
12 and the positioning of the vacuum chamber 4 of the vacuum-suction mechanism K with
respect to height or vertical direction may carried out by causing the vacuum suction
force generated in the vacuum chamber to be substantially received by the wheels 2
in order to prevent the bottom of the vacuum chamber 4 from coming into abutment against
or contacted with the wall H.
[0015] Reference numeral 16 designates fitting members provided on the front face of the
frame 11 so as to project in forward direction therefrom. A lifting rope extends through
the fitting member 16 between a winch and the frame 11. The movement of the apparatus
may be effected in the same manner as in the embodiment described with reference to
Figs 1. to 5. More particularly, the crawler is pulled by means of the winch. Alternatively,
the crawler is moved by self-propelling operation by connecting part of the wheels
2 to a drive motor and connecting the remaining wheels to the drive wheel by means
of a chain or the like. The working equipment S may be mounted on the frame 11 so
that the entire equipment S or a part thereof which is arranged adjacent to the wall
H, is spaced from the wall H by a distance sufficient to avoid any obstacle on the
wall H.
[0016] When the crawler of the illustrated embodiment travels on the wall H, while being
suctionally held thereon, only the particular vacuum-suction mechanism(s) K encountering
the projection T on the wall H is lifted by means of the air cylinders 15 from the
wall H to pass the obstacle. concurrently, the working equipment S will likewise avoid
the projection T. During this time, the rest of the vacuum-suction mechanisms still
move on the wall H while being held thereon by suction, so that the crawler continuously
travels on the wall H. When the vacuum-suction mechanism K which was lifted to avoid
the projection T has passed the projection T, it is again lowered down to the wall
H by means of the air cylinder 15, being held thereon by suction. Correspondingly,
the working equipment S is likewise lowered to the wall H for further operation.
[0017] In the embodiment shown in Figs. 6 to 9, one vacuum-suction mechanism K is arranged
on each side of each connecting plate 12. However, a plurality of vacuum-suction mechanisms
K may be arranged on each side of each connecting plate 12. The vacuum chambers 4
may be formed at the connecting plates 12, wherein a suitable number of recesses 4₂,
seal members 5 and members 6 are provided on the bottom of each of the connecting
plates 12. Further, the vacuum chambers 4 may rather be arranged in a manner other
than the above-described manner of the first embodiment, wherein the chamber 4 together
are mounted in groups on the connecting plates 12. For example, they may be mounted
on the frame 11 being vertically movable by the air cylinders 15. Moreover, any suitable
lifting or spacing means other than the air cylinder 15 may be conveniently used in
the present invention as far as it can enable the wall vacuum-suction mechanism K
to avoid the projection T on the wall H.
[0018] As can be seen from the foregoing, the crawler of the present invention constructed
as described above substantially decreases frictional resistance between the apparatus
and the wall of a building or the like, and thereby improves the efficiency of the
crawler and reduces the power required for driving the crawler, as compared with the
conventional crawler. More particularly, in the conventional apparatus, the trumpet-shaped
seal member provided on the lower peripheral edge of the bowl-like sucker is in close
contact with the wall by vacuum suction, thus substantially increasing frictional
resistance between the seal member and the wall. In contrast thereto, the flexible
seal member in the present invention provided so as to surround the recess of the
vacuum chamber is arranged so that it projects vertically by a suitable length from
the bottom of the vacuum chamber and the low friction member is mounted on the distal
end of the seal member. The seal member and low friction member are thin-walled parts.
Such construction permits the flexible seal member to come into close contact by means
of the low friction member with the wall while being held on the wall by the low friction
member by vacuum suction, thereby preventing the bottom of the vacuum chamber from
coming into contact with the wall. This is more efficiently accomplished when the
positioning of the wheels with respect to the frame and the position of the vacuum
chamber in vertical direction of the crawler is suitably chosen. Thus, the apparatus
of the present invention highly reduces frictional resistance and can smoothly travel
on the wall by means of the low friction member while being held thereto by the low
friction member.
[0019] The crawler of the present invention also continuously and positively travels on
the wall irrespective of any obstacle such as a projection on the wall, and thereby
enables the working equipment to safely and efficiently carry out dangerous operations
at an elevation. More particularly, the conventional crawler is constructed so as
to travel on the wall by means of one single large-size sucker, and thereby fails
to continuously travel across a projection on the wall so that it is required to stop
the movement and to remove the entire crawler from the wall in order to enable the
crawler to pass the projection and then to again place it on the wall for restarting
the operation. In contrast thereto, a plurality of the vacuum-suction mechanisms is
arranged in the present invention at the front and rear portions of the frame in a
manner to be vertically movable with respect to the frame. Such construction of the
present invention permits the vacuum-suction mechanisms to be lifted in order to avoid
a projection, only when they encounter the projection, and the remaining mechanisms
are kept on the wall by suction, so that the apparatus may continuously travel on
the wall irrespective of the projection while being held on the wall by suction.
1. A vacuum held crawler comprising:
- a frame on which working equipment is to be mounted;
- a vacuum-suction mechanism mounted on said frame and wheels mounted on said frame
characterized in that said vacuum-suction mechanism includes a vacuum chamber formed
at the bottom thereof having an opening and being connected to vacuum generating means,
a flexible seal member mounted on the bottom of said vacuum chamber in such a menner
that it surrounds said bottom opening of said vacuum chamber and projects in downward
direction by a suitable distance from the bottom of said vacuum chamber, and that
a surface contact mechanisms including a low friction member having a low friction
coefficient is mounted on the distal end of said seal member and being in close contact
with a wall for receiving the vacuum suction force acting between the crawler and
the wall and for traveling on the wall.
2. A crawler as defined in Claim 1, wherein a plurality of said vacuum-suction mechanisms
are provided at the front and rear portions of said frame.
3. A crawler as defined in Claim 1 or 2, wherein said vacuum-suction mechanism each
being arranged so as to be vertically movable by lifting means, thus avoiding any
obstacle on the wall.