Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Application for Paten~
Inventor. Spencer D. Cottam
Title: Robotic Crawling Device
Specification
Field o~ the I~vention
Thi~ invention relates generally to robotic devices
for accessing vertical and overhead surfacesO More
specifically, the invention relates to such robotic
5 . devices tha~ can carr~ other equipment such ~s surface
cleaning devices,
Background of the Invention
.~
ny industrial activities require access to surfaces
~hat ca~ ~ot be e~sily accessed by workers. ~or example/
19 . large storage tanks and ships require occasional surfacing
cleaning and are difficult to access without costly
scaffoldi~g or lift devicesO Furthermore, some surfaces
such as walls and ceilings within storage tanks and
nuclear reactors require elaborate and costly safety
1~ precautions or ~ccess by workers.
Remote controlled robots are replacing workers in a
number of industrial activities and thus reducing the risk
of injury or dea~h to the work for~e. A robot that could
carr~ equipment across a wide variety o~ vertical and
~0 o~erhead surfaces could be used for many industrial
activi~ies such as surface cleaning.
- Express kbil l~o. B95174516
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Summary of the Invention
The robotic crawling device of ~he present invention
can traverse vertical and overhead sur~aces and comprises
outer gripping means for gripping the surface, inner
S grippiny means for gripping the ~urface, ~he i~er
gripping means being positioned withln the outer gripping
means~ and cr~wling means for raising~ advancing, and
lowering ~he ou~er and inner gripping means in sequence.
In a preferred embodiment, the robotic cxawling
device further comprises a platform for mounting o~her
devices~ The platform is mounted to the crawling device
such that the platform remains a su~stantially fi~ed
distance from the surface.
Another aspect of the preferred embodiment is the u~e
of suction to grip the surface by maintaining a low
pressure between the surface and the platform.
Alternati~ely, the crawling device can be adapted to grip
metal surfaces with electromagnets. P~rther, the crawling
device can includ~ a turning mechanism for changing th~
~0 direction o~ movement acro~s ~he surface~
.
Brief Description of ~ e ~rawin~s
Figure 1 i~ a top view of a preferred embodiment of
the robotic crawling device of ~he pressent invention~ the
preferred embodiment using suction to grip the surface and
~5 having ~ pla~fonn for mounting other devices and a turnin
. mech~nism;
Figure 2 is a sectional view of ~h~ xobotic crawlin~ .
device of Figure 1 as indicated by line 2 2 on Figure 1;
Figure 3 is an enl~rged view of ~he righk end of
Figure ~;
Figure 4 is a top view of the robotic crawling device
of Figure 1 wikh ~he platform removed as shown by line 4-4
on Figure 2,
. Figures 5A, 5B, 5Ct SD, and 5E pxesent schematic
represenkations of the crawling motion for the robotic
crawling device of Figure lt
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Figure 6 is a sectional view of the robotic crawling
device of Figure l as indicated by line 6-6 on Figure 1
and better shows the details of a preferred crawling
mechanism;
Figures 7 and 8 are detailed views of components of
~he preferred crawling mechan.sm of Figure 6;
Figure 9 is a sectional view o a preferred mechanism
for maintaining low pressure within the crawling device;
and
Figures lOA, lOB, lOC, lOD, and lOE present further
schematic representations of the preferred crawling motion
which correspond to Figures 5A, 5B, 5C, 5D, and 5E,
respectively.
Detailed Description of a Preferred Embodiment
In the drawings, a platform 10 i5 provided for
mounting other devices thereon (not shown), such as
Applicant's surface cleaning device which is described in
U.S. Patent No. 4,531,253. The attac~nt of the cleaning device orother
equipment to the platform 10 may be by any conventional
means such as bolts, or by welding The platform 10 is
capable of traversing horizontal and vertical surfaces,
including overhead surfaces, while the platform 10 remains
a substantially fixed distance from the surface S as
described below. The platform 10 adheres to the surface S
by suction and is connected to a suction source as
described below. A hole 12 in the platform 10 is provided
for connection with the suction source.
The use of suction to hold the platform lO to the
surface S allows use of the device with a variety of
surfaces such as concrete or steel. When the device is
used predominantly on one type of surface, other
mechanisms for holding the platform to the surface S can
be used such as electromagnets (not shown) for gripping
steel as further mentioned below.
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Reerring to Fig. 2, the platform 10 is fastened by
screws 14 or other fasteniny means ,to mounting blocks 16.
The mounting ~loc~s'16 mount vertical shafts 18 wh ch are
pressed into holes 19 in ~he mounting ~loc~s 16. A
mounting frame ~0 slidably eng~ages the vertical ~hafts 18
using linear b~arings 22. Mov~merlt vf the mounting frame
~0 o~ the vertical shafts 18 is preferably limited by
clamps ~3 fastened ~o the free ends ( lower ends AS viewed
in ~ig. 23 o~ the vertical shafts 180
C~ shafts 24 are rotat~)ly mounted in bearings 25
(Fig. 43 wilth the mounting fxame 20~ Football=shaped cams
~6 are fixed to the cam shafts 24 usiIlg keyways and set
screws or othex fastening means (not shown~O The
footballrshaped cams 26 are spaced from the mounting fra~e
20 by spacer sleeYes 27 mounted on ~b.e shafts 24 on eàch
side vf the bearings 25 (Fig. 6). The football-shaped
cams 26 engage rollers 28 (Fiy. 2) th.at are mounted with
the mounting blocks 16. The cam shafts 24 are rotated by
a drive motor 30 (FigsO 2 and 4) which is mounted to the
mounting frame 20 by a motor support 32O The drive motor
30 has a drive shaft 34 (FigO 4) th~t is in driYing
connection with the cam shafts 24 thr~ugh a dri~e gearbox ~:
36. The gearbox 36 has a central chal~bex 38 that holds a
plurality of gears ~hat transfer power from the drive
shaft 34 to the cam shafts 240
As will be explained, when the plakform 10 adheres to
the surface S by suction, the rollers 28 ride upo~ the
rotating football shaped cams 26~ As explained below, the
football-~haped cams 26 and cam shafts 24 move toward and
away from the surface S (FigO 2)~ but: the shape o~ the
foo~ball-shaped cams 26 causes t.he roller~ 28 and the
platform 10 to remain a substantiaily fixed diskance fxom
the surface.
Referring to Figs~ 6, 7 and 8, lnner circular cams 40
(Fig. 8) are eccentrically mounted to the cam shafts 24
outside the :Eootball cams 26 by keyways and set screws or
other fasten:ing means (not shown)0 The inner circular
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cams 40 are rotatably mounted in bearings 44 within inner
support brac~ets 42 The inner support brackets 42 axe
attached h~ screws 6r other fastening means ~not shown) to
an inner housing ~6. The inner housing 46 preferably
includes a turning mechanism as described belowO With the
turning mechanisrn, the inner housing 46 is indirectly
connected to an inner annular seal 48 which engages the
surface S when the inner housi.ng 46 is pressed against the
surface S as described belowO
. Outer circular cams 50 (Fig. 73 are eccentrically
mounted to the cam shafts 24 outside the inner circular
cams 40 using Xeyways and set screws or o~her fastenin~
means ~no-t sho~l). The outex cam~ 50 are similar to th&
inner cams 40 except that -the outer cams 50 are offset dn
the shafts 24, 180 degrees with respect to the inner cams
40 when fixed to the cam shafts 24 ~compare FigsO 7 and
8). The outer c~ms 50 are rotatably mounted in bearings
54 within outer support brackets 52. The outer support
brackets 52 are fastened by screws or other -fastening
~0 means ~no~ shown) ~o an out~r housing 56 (FigO 6~.
Referring to Fig. 3, ~he outer housing 56 is
connected to an outer annular seal 58 which engages the
surface S when the outer housins 56 is pressed against the
surface S, as described belowO The outer housing 56 is
connected to a housing body 60 by sc~ews 62 or other
fastening me~ns. The housing body 60 is connected to a
housing body retaining ring 64 by screws 66 or other
fas~eniny means. The function of the re~aining ring 6~ is
described in more detail below. The outer an~ular seal 58
is ~i~e~ ~o -the retaining ring 64 by glue or other
suitable known ~astening means~ Alternatively, ~he outer
seal 58 can be fixed to a removable ring ~not shown) which
can be fastenled to ~he retaining ring 64 by screws or
other fastening means for easy replacement of the outer
3~ seal 58.
~ n upper chamber U (Figs. 3 and 5A) is formed within
the outer housing 56 by con~ecting the outer housing 56 to
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the platform 10 and to the inner housing 46 by flexible
annular diaphragms 70 and 80, respectively. A first
flexible annular d.~aphxagm 70 is connected ko the outer
housing 56 with an out~r housing retaining ring 72 using
screws 6~, and is ~urther connected to the platform 10 by
a platform retaining ring 74 usiny screws 76 or other
fastening means. An annular notch 78 in ~he outer housing
~6 allows movement of the flexible annular diaphxagm 70 as
the outer housing 56 moves relative to the platform 10 as
described below>
The outer housing body 60 and ~he outer housing
retaining ring 64 hold a second flexi~le annular diaphra~m
80 which is connected to the inner housing 46 by an inn~r
housing retaining ring 81 using screws 82 or o~her t
fa~ten~ng means. The second flexible annular diaphragm 80
splits the interior of the outer houslng 56 into ~he upper
chamber U, which is s~bstantially disposed between the
platform 10 and the inner housing 4~i, and an annul ar j;
ch~nber A ~see Figs. 3 and lOA3, whirh is substantially
~0 disposed between the inner annular se!al 48 and the outer
annular seal 58.
The preferred embodiment of the invention inc~udes a
turning mechanism as part of the iI~er housing 46~
Referring to Figs. 2 and 3, a ring gear 84 rotatably
engages ~he inner housing 46 by slidi.ng within a teflon
ring bearing 8~ which is mounted between ~he ring gear 84
and the inner retaining ring 810 The ring gear 84 is held
in place ~y friction, and rotates within the inner housing .
-retaining ring 81. An O ring 87 (FigO 3~ iS mounted
between the re~aining ring 81 an~ the ring gear 84 ~o
minimize leakage ~or reasons ~hat are more apparent below~
The ring gear 8~ is further retained by a cover plate 88
which is connected to the inner housing 46 by a screw 89
(Fig. 23 or othex fastening means. ~ pinion gear 90 is
rotatably mounted between ~he i~ner housing 46 and ~he
cover plate 88 and engages the ring gear 840 The pi~ion
gear 90 is fixed to a shaft 92 which is rotatably mounted
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on ~e inner housing 46. A conventional turning motor 94
and a turning gea.r box 96 are mounted on the inner housing
4~ to .rotate -~he prnion gear 90. Rotation of the pinion
gear 90 causes the inner housing 46 to rotate relative to
the riny gear 84 and is capable of changing the direction
of travel or lateral movement of the inner housing 46 when
the ring year 84 is in contact with the surface through
the inner annular seal 48, The~ inner seal 48 is fixed to
~he ring gear ~ by glue or other fastening meansO
19 Alternati~ely, the inner seal 4~ can be fixed to a
removable ring (not shown~ which can be fastened to the
ring gear 84 by screws or other faste~ling means for easy
replacement of the i~ner seal 480
An inner ch~mber I ~FigsO 2 and lOA) is formed by a~d
1~ contained withi~ the inner housing 4~i when the i~ner
annular seal 48 is in contact with thP surface S. The
inner chamber I i~ in fluid communicat:ion with the upper
chamber U, through holes 47 (FigO 2) in the inner housing
46 if necessary, so tha~ suction applied to either the
inner chambPr I or the upper chambeI U reduces the
pressure within both chambersO The inner chamber I and
- upper chamber U are not in fluid commlmication with the ~
annular chamber A when ~he inner seal 48 is in contact
with the surfares (as shown in Figures lOA~ lOC, lOD and
lOE) although there may be some leakage therebetween, as
2xplained below~ All three chambers A, U, and I are in
fluid communication when the inner seal 48 is raised from
the surface ~as sho~n in Figure lOB).
Referriny to Fig. 9, the source of suction is
preferably in direct fluid communication with the i~ner
chamber I. A hole 100 in the inr,er-housing ~6 mounts a
ho~e fitting 102 which is secured to the inner housing 46
by screws 10~ or other fastening means. ~ short tube 106
is connected to the hose fitting 102 between the inner
~5 housing 46 and the cover plate 88. The short tube 106
terminates above a hole 108 in the cover plat~ 88. A
second hose fitting 110 is mounted in the hole 1~ in the
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platform 10 using screws 112 or other fastening means.
flexible suction hose 114 is fastened between the first
and second hose fi~tings 102 and 110 by clamps or cther
fa~tening means. Attachment o the ~uction source to the
inner chamber I is preferred because wate~ and other
foreign substances sn the surface S are drawn into the
suction source without passing t~rou~h the upper chamber U
which contai~s most of the mec:hanical partsO
The suction source is preferably of a sufficient
capacit~ ~o adhere ~he platform 10 to a porous surface
such as concrete by lowering the pressure in the upper and
inner chambers U and I relative to the pressure which i8
acting externally of t~e apparatusO The suctio~ sourc&
must also lower the pressure in the annular chamber A ea~h
time the outer housing 56 is lowered t:o ~he surface S and
the inner housing 46 is raised from the surface SO A
suitable suction source is shown in ~'igure 9. A short
pipe 116 is threaded or otherwise fast:e~ed to the hole 12
in ~he platfonm 10 and mounts a venturi ~alve 118. The
venturi valve 118 pre~erably has mllltiple venturi
restrictions for creating suction within ~he pipe 116 when
a flui~, such a~ air, from a fluid source-12Q., ~uch as an ~-
air compressor, is passed through the venturi valv~ 1180
The suction source reduces the pressure within the
suctio~ hose 114 which reduces ~he pressure or creates a
partial Yacuum in the inner chamber I betwPen the surface
and the cover plate 88. A second hole 130 in the cover
plate 88 helps to reduce the pressure between the cover
plate 88 and the inner housing 46 so khat the pressure is
guickly reduced wi~hin ~he inner chamber Io A filter 132
is mounted ovex ~he hole 130 in the cover plate 88 to
prevent particles from passing through the hole ~30 when
the source of suction is shut off.
When used on a porous surface, the inner annular
seal 48 and the outer annular seal 58 will not prevent
leakage. However, leaXage around the seals 48 and 58 may
assist in ra:ising the inner housing 46 and -the outer
~ 9-.
housing ~6 ~y helping to equalize the pressure on both
sides of each seal as it is raised. If the inner seal 48
~nd ~he outer seal ~8 are used on a surface ~lat does not
allow suf~icient leakage around the seals to the point
that ~he ~eals are difficult to raise~ compressible vents
148 and 158 ~Figs. 2 and S) i:n the seals 48 and 58,
respective:Ly, pxovide adequate leakage. The compressible
~ents 148 and 158 are preferably small horizontal slots in
~h~ seals 48 and 58. The vent~s 148 and 15a are closed
when the seals 48 and 58 are press~d against the surface
as described below and opened to equalize the pressur~ on
~o~h side~ of the seals as the force pressing against each
seal is lelieved as described beluwO Alternatively, ~h~
device can be pro~ided wi~h other mechanisms for
1~ equalizing the pressu.re on both sides of each seal 48.and
. . .
In operation, the fluid source 120 and venturi valv~
118 create a low pressure or partial vacuum in the pipe
116 which in turn creates a low pressure in ~he upper
~0 chamber U and the inner chamber I so that atmospheric
pressure acts on the platform 10 to hoLd it or move it
- toward the sur~ace ~. ~he pla~form 1~) pushes the cam ~-
shafts ~4 toward the surface S through the rollers 28 and
~he foo~ball-shaped cams 260 The cam shafts 24 are
po~itioned relative to the surf~ce S by the inner housing
46 or thP outex housing 56 through the inner cams 40 and
-the inner suppor-t brackets 42 or the outer cams 50 and the
outer support brackets 52, respectively. As shown by
Figs. 5A-E and Figs. lOA-E, rotation of ~he cam shafts 24
~y the drive motor 30 causes the cam shaft~ 24 to shift
the atmospheric force applied sn the platform 10 between
the inner housing 46 and the outer housing 56 as the inner
cams 40 and ~he outer cams 50 sequentially raise and lower
the inner housing 46 and the outer housing 560 The inner
cams 40 and the outer cams 50 also advance the inner
housing 46 ancl the outer housing 56, respectively, as each
housi~g is rai~ed and lower~d. Thus, the inner housing 46
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and the outer housing 56 move across the surface with a
crawling motion whereby the housings 46 and 56 are
sequentiall~ raised, advanced, and lowered.
The crawling motion for the inner housing 46 and the
5 outer housirrg 56 is schematically diagramed in Figs. 5A,
5B, 5C, 5D, 5E, lOA, lOB, lOC, lOD, and lOE. In FigsO 5A
and lOA, both ~he inner annular seal 48 and khe outer
annular ~eal 58 are in contact; wi~h the surface S and a
- low pressure exists in the upper chamber U, the iDner
chamber I, and the annular ch.lmber Ao In ~hi~
configura~ion, ~he outer housing 56 has been advanced to
the left with respect to the inner housing 46 and ~he
outer cams 50 an~ the inner cams 40 are in ~he relativ~
positions shown in Fig. 5A. I
lSIn Figs. 5B and lOB, the carn shafts 24 have been
rotated ninet~ degrees ( counterclockw.ise ) . The rotation
of the cam shaft~ 24 causes the outer cams 50 and the
inner c~ns 40 lto rotate within ~he ou-ter support brackets
52 and the inner support brackets 42~ respectively. T~e
outer support ~rackets 52 r~nai~ in a. fixed position due
to contact with the surf~ce S and ~he counterclockwise
rotation of the outer cams 50 and the inner c~n~ 40 raises
and ad~ances the inner housing 46 and th~ inner annul~r
seal 48 to the position shown in FigO lOXo The movement
of the inner c.~ms 40 and the outer c~ns 50 rais~s the cam
shafts 24 wi~h respect to the surface S; howeverJ the
rotation of the football-shaped cams 26 by the cam shafts
~4 allows the platform 10 to remain a substantially fixed .
-distance from the surface SO The low pressure remains in
the upper chamber U, the inner chambex I, and the an~ular
chamber A for the positio~ of the device shown in Fig.
lOB.
In Figs. 5C and lOC, the cam shafts 24 are fur~her
rotated ninety degrees (counterclockwise) from the
position sho~n in ~ig. SB, which causes further rotation
of the outer cams 50 and the inner cams 40 in the outer
support brackets 52 and the inner support bracket~ 42,
respectively. As the outer suppor-t brackets 52 remain in
fixed positions due to contact with the surface S, the
inner cams 40 and t~e inner annular seal 48 move to the
let from the position shown in FigO 5B to ~he position
shown in Fig. 5~. The movement o~ the inner cams 40
lowers and ad~ances the inner housing 46 until the inner
annular seal 48 again contacts the surface S a~ shown in
Fig~ 10~'. The movemant of ~he inner cams 40 an~ the outer
cams SO lowers the c~m ~haEts. ~4 wit~ respect to the
surface S; however, rotation of the football-shaped cams
26 by the cam shafts 24 causes the platform 10 to remain a
substantiall~ fixed distance from-the surface S. The low
pressure remains in the upp~r chamber U, the inner ch ~ er
I, and the annular chamber ~.
In ~'igs. 5D and lOD, th ~am shafts 24 are further
rotated ninety degrees ~countercloc}cwise3 from the .
position shown in Fig. 5C, causing further rotation of the
outer cams 50 and the inner cams 40 within the outer .
support brackets 52 and t~e inner support bracke ts 42,
~0 respectively. Th~ inner support brackets 42 remain in a
Eixed posi-tion due to contact with the surface S . The
- counterclockwise rotation of the innel~ cams 4~ within the
inner support brackPts 42 causes the outer cams 50 to move
from the positio~ shown in FigO 5C to the position shown
25 - in Fig. SDo The movement of the outer cams 50 raises and
adYances the auter housing 56 ~nd the outer annular ring
58 from the position sho~n in Fig. lOC to ~he position
shown in Fig. lOD, The movement of the inner cams 40 and .
the outer cams 50 raises ~he cam shafts 24 with respect to
the surface S; however, the rotation of the
- oo~ball~shaped cams 26 by the ~am shafts 24 allows the
platform 10 to remain a substantially fixed distance from
the surace S. For the position of thP device shown in
Figs. SD and lOD, a low pressure remains in the upper
chamber U and the i~ner chamber I al~hough the raising of
the outer annular seal 58 raises the pressure in the
annular ch~er Ao
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In Figs. 5E and lOE, ~he cam shafts 24 are further
rotated nine~y degrees ~counterclockwise~ from the
position shown in F~g. 5D, causing ~he outer cams SO and
~he inner cams ~0 to further rotate wikhi~ the outer
support brackets ~2 and the ilmer support brackets 42,
respectiYely. The inner support brackets ~2 remai~ in a
fixed position ~ue to contact with the surface SO The
counterclocXwise rotation of ~le inner cams 40 moves the
ou~er cams 50 fxom the position shown in Fig. 5D to the
- 10 position shown in Fig. 5E which is the same as the
starting position~ Fig. 5Ao The movement of the outer
cams 50 lowers and advances the outer housing 56 until
the outer annular seal 58 contacts ~he surface S. Th~
movement of ~he in~er cams 40 and the outer cams 50 low~rs
1~ the cam shafts 24 with respect to the suxface S; however,
rotation o~ the ootball-shaped cams 2.6 by ~he cam shafts
~4 causes the platform 10 to remain a substantially fi~ed
distance from the surface S. For the position of the
device shown in Figs. 5E and lOE~ the :low pressure remains
in the upper chamber U and the i~ner chamber I. A high
pressure remains in the annular chamber A until rotatio~
of the cam shafts 24 shifts the atmospheric force applied
on the platform 10 rom ~he inner annular seal 48 to the
outer annular seal 5 and allows suEficient leakage
~5 between the inner an~ular sPal 48 and the surface S for
the suction source to reduce the pressure in the annular
chamber A, thus returning the device to the configuration
and condition de~cribed for Figs. 5A and lOAo
- . While the robotic crawling device is advancing, if it
is desired to change its direction of movement, a switch
(not shown) to ~he turning motor 94 is turned on or
activated so as to cause the motor 94 to cha~ge ~he
direction of ~ravel by rotating the innex housing 46 about
the ring gear 840 When the desired ~irection is reached,
the switch is turned off ~o deac~ivate the motor 94~ The
illustrated embodiment of the device will turn only while
the inner a~lular seal 48 grips the surface S and ~he
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outer annular seal 58 is not grippins the surace S. A
circuit control mechani~m (not shown) for contr~lliny the
turning motor 9~ cah be used to pre~ent excessive wear on
the turning motor 94 which migh~ otherwise occur if ~he
S mo~or is operat~d when both ~he inner and outer seals 48
and ~8 are gripping the surface~ S~
'~hen usecl with a metal ~urface, the illustrated
device can ba easily con~erted from suction gripping to
magneti~ gripping by replacing the inner seal 48 and ~he
outer seal 58 with inner and outer electromagnekic rings
having substantially the same shape as the seals. The
electromagnetic .rings would then be se~uentially energized
to seguentiall~ hold the cam shafts ~4 to the surface
through the iI~ner housing 46 and the outer housing 56.
Springs (not shown) could be mountad on ~he vertical
shafts 18 between the mounting frame 20 and the clamps 23
or between the mounting frame 20 and the mounting blocks
16, to hold the rollers 28 against the football-shaped ,~
cams ~
The foregoing disclosure and description of the
invention are illustrativa and explanatory thereo~, and
- various changes in the size, shape ~nd materials, as well
as in the details of the illustrated construction may be
made withou~ departlng fxom the spirit of the invention.
