U.S. patent application number 11/424380 was filed with the patent office on 2006-10-05 for fluid operated self aligning roller.
Invention is credited to James J. Donnenhoffer.
Application Number | 20060219527 11/424380 |
Document ID | / |
Family ID | 37068983 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060219527 |
Kind Code |
A1 |
Donnenhoffer; James J. |
October 5, 2006 |
FLUID OPERATED SELF ALIGNING ROLLER
Abstract
A pressurized bladder system is associated with a first roller.
In one embodiment, the conveyor belt extends around the roller
which is automatically centered by the bladder. In alternate
embodiments, the first roller is positioned adjacent an impression
roller with the bladder operable to control the positioning of the
first roller relative to the impression roller.
Inventors: |
Donnenhoffer; James J.;
(Terre Haute, IN) |
Correspondence
Address: |
WOODARD, EMHARDT, MORIARTY, MCNETT & HENRY LLP
111 MONUMENT CIRCLE, SUITE 3700
INDIANAPOLIS
IN
46204-5137
US
|
Family ID: |
37068983 |
Appl. No.: |
11/424380 |
Filed: |
June 15, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11186180 |
Jul 21, 2005 |
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11424380 |
Jun 15, 2006 |
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10910116 |
Aug 3, 2004 |
6981583 |
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11424380 |
Jun 15, 2006 |
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Current U.S.
Class: |
198/806 |
Current CPC
Class: |
B65G 23/44 20130101;
B65G 39/16 20130101 |
Class at
Publication: |
198/806 |
International
Class: |
B65G 39/16 20060101
B65G039/16 |
Claims
1. A fluid operated device for automatically aligning a roller
comprising: a roller frame; a roller with opposite ends and having
a first axis of rotation with said opposite ends rotatably mounted
to said roller frame; and, a support frame having said roller frame
movably mounted to allow said roller frame to move relative to said
support frame to allow said roller to skew from said first axis of
rotation to a second axis of rotation; and, a first pressurizable
bladder positioned between said roller frame and said support frame
and normally urging said roller to move from said second axis of
rotation to said first axis of rotation.
2. The device of claim 1 and further comprising: a fastening device
extending between and pivotally connecting said roller frame to
said support frame with said support frame being fixed limiting
movement thereof.
3. The device of claim 2 wherein: said roller frame and said
support frame face each other to form a cavity in which is located
said bladder, said roller frame and said support frame have stops
to limit expansion of said bladder where said roller frame moves
toward said support frame and to allow expansion of said bladder
where said roller frame moves away from said support frame.
4. The device of claim 3 wherein: said roller frame and said
support frame have length with said bladder extending substantially
along said length.
5. The device of claim 4 wherein: said roller frame has an inverted
L-shape and said support frame has an upright L-shape both facing
each other to define said cavity.
6. The device of claim 1 and further comprising: a second
pressurizable bladder positioned between said roller frame and said
support frame and normally urging said roller to move from said
second axis of rotation to said first axis of rotation.
7. The device of clam 6 wherein: said roller frame and said support
frame have length with said first bladder and said second bladder
extending together substantially along said length said first
bladder and said second bladder have constant internal fluid
pressure urging said roller to rotate along said axis.
8. The device of claim 7 wherein: said support frame has a C-shape
and said roller frame includes a pair of spaced apart walls
extending into said C-shape defining a pair of cavities receiving
said first bladder and said second bladder.
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. A roller to control flow of liquid to an impression cylinder
comprising: a frame; a rotatably mounted roller adjacent an
impression cylinder forming a liquid receiving area between said
roller and said cylinder; an axle having a longitudinal axis with
said axle extending through said roller and mounting said roller to
said frame, said axle having opposite first and second ends movably
mounted to said frame to allow said axle to move relative to said
roller and allow said axis to move from a first position to a
skewed position relative to said impression roller; and, a first
pressurizable bladder extending between said roller and said axle
and having a constant internal pressure to urge said roller against
said cylinder at a constant pressure even though said axle moves
between said first position and said skewed position.
16. The roller of claim 15 and further comprising: a second
pressurizable bladder extending between said roller and said axle
and having a constant internal pressure to urge said roller against
said cylinder at a constant pressure even though said axle moves
between said first position and said skewed position.
17. The roller of claim 15 wherein: said bladder extends
spiralingly around said axle along the length thereof.
18. A fluid operated device for moving the axis of rotation of a
roller relative to the longitudinal axis of a main flame
comprising: a roller frame; a roller with opposite ends and having
an axis of rotation with said opposite ends rotatably mounted to
said roller frame; and, a main frame having a longitudinal axis
positioned angularly relative to said axis of rotation with said
roller frame movably mounted to said main frame to allow said
roller frame to move relative to said main frame to allow said
roller to move angularly changing said axis of rotation relative to
said longitudinal axis; and, a first pressurizable bladder
positioned adjacent said roller frame controlling said roller to
move said axis of rotation relative to said longitudinal axis.
19. The device of claim 18 and further comprising: a support frame;
and, a fastening device extending between and pivotally connecting
said roller frame to said support frame with said support frame
being fixed limiting movement thereof.
20. The device of claim 19 wherein: said roller frame and said
support frame face each other to form a cavity in which is located
said bladder, said roller frame and said support frame have stops
to limit expansion of said bladder where said roller frame moves
toward said support frame and to allow expansion of said bladder
where said roller frame moves away from said support frame.
21. The device of claim 20 wherein: said roller frame and said
support frame have length with said bladder extending substantially
along said length.
22. The device of claim 21 wherein: said roller frame has an
inverted L-shape and said support frame has an upright L-shape both
facing each other to define said cavity.
23. The device of claim 18 and further comprising: a second
pressurizable bladder positioned between said roller frame and said
support frame and normally urging said roller to move said axis of
rotation.
24. The device of claim 23 wherein: said roller frame and said
support frame have length with said first bladder and said second
bladder extending together substantially along said length, said
first bladder and said second bladder have constant internal fluid
pressure urging said roller to rotate along said axis of
rotation.
25. The device of claim 24 wherein: said support frame has a
C-shape and said roller frame includes a pair of spaced apart walls
extending into said C-shape defining a pair of cavities receiving
said first bladder and said second bladder.
Description
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 10/910,116, filed Aug. 3, 2004.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to the field of
conveyor belts.
DESCRIPTION OF THE PRIOR ART
[0003] Many conveyors incorporate a continuous looped belt
extending around and supported by a plurality of rollers. Through
continued use, the belt may become misaligned or off center
relative to the rollers resulting in damage to the edged portion of
the belt and even stoppage of the conveyor. Further, articles
conveyed by the belt are subjected to movement along a line other
than the longitudinal axis of the conveyor. Thus, it is the
practice to periodically stop the conveyor in order to realign the
belt relative to the central axis of the conveyor resulting in down
time and added cost.
[0004] In order to solve the aforementioned problem, a variety of
self correcting or self centering devices have been incorporated
into conveyers in an attempt to automatically align the belt. One
such device is shown in the U.S. Pat. No. 6,668,526 issued to Josef
Schmidt. The Schmidt device includes a tracking roller pivotally
mounted to a frame to adjust the flow path of the web of material
in a packaging machine. Another approach is disclosed in U.S. Pat.
No. 5,833,171 issued to J. C. Harris. In the Harris device, a
rotating sleeve is coaxially mounted upon inner non-rotating but
pivoting sleeve. As the web runs over the rotating sleeve, any
imbalance in lateral web tension will cause the non-rotating
pivoting sleeve to pivot at its center with respect to the
longitudinal axis of the shaft permitting the non-rotating pivoting
sleeve and coaxial rotating sleeve to pivot on the side of least
tension until the web tension is equalized across the coaxial
sleeve. J. C. Harris also discloses in his U.S. Pat. No. 5,833,106
a similar web tension equalizing roll and tracking apparatus
wherein the equalizing roll has a common axis with a shaft mounted
horizontally on two bearings for rotation.
[0005] The concept of utilizing a pressurized bladder or bladders
for centering a conveyor roller may also be utilized in the
construction of rollers for applying or metering various liquids
onto an impression or applicator roller. For example, a ductor
roller is movable to and from an impression roller to evenly apply
liquid, such as ink, onto the impression roll. Likewise, a metering
roller may be located adjacent an impression roller to control the
amount or meter the liquid applied to the impression roller. In
both cases, the doctor roller or metering roller may be cocked
through usage and/or improper set-up relative to the impression
roller and it is therefore desirable to incorporate an automatic
device to evenly space the ductor roller/metering roller relative
to the impression roller. I have therefore disclosed herein various
pressurized bladders to evenly space the ductor roller/metering
roller relative to the impression roller.
SUMMARY OF THE INVENTION
[0006] One embodiment of the present invention is a fluid operated
device for automatically aligning a roller. A roller with opposite
ends has a first axis of rotation with the opposite ends rotatably
mounted to a roller frame. A support frame has the roller frame
movably mounted thereto to allow the roller frame to move relative
to the support frame and the first axis of rotation to become
skewed to a second axis of rotation. A first pressurizable bladder
is positioned between the roller frame and the support frame and
normally urges the roller to move from the second axis of rotation
to the first axis of rotation.
[0007] Another embodiment includes a liquid applicator with a first
rotatably mounted roller having a first cylindrical surface and a
second rotatably mounted roller having a second cylindrical surface
positioned adjacent the first cylindrical surface forming a liquid
receiving area. An axle has a longitudinal axis that extends
through the second roller but moves relative to the first roller to
allow axis to become skewed moving from a first position to a
second position. A pressurizable bladder extends between the second
roller and the axle and has a constant internal pressure to urge
the second roller against the first roller at a constant pressure
even though the axle moves between the first position and the
second position.
[0008] It is an object of the present invention to provide a device
for automatically spacing a first roller apart an equal distance
along its length from a second roller.
[0009] A further object of the present invention is to provide a
ductor roller or metering roller that is automatically positioned
relative to an impression roller by means of a pressurized bladder
or bladders.
[0010] Related object and advantages of the present invention will
be apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a conveyor incorporating the
fourth alternate embodiment of the present invention.
[0012] FIG. 2 is an enlarged cross-sectional view taken along the
line 2-2 of FIG. 1 and viewed in the direction of the arrows.
[0013] FIG. 3 is an end cross-sectional view taken along the line
3-3 of FIG. 2 and viewed in the direction of the arrows.
[0014] FIG. 4 is an enlarged fragmentary cross-sectional view taken
along the line 4-4 of FIG. 2 and viewed in the direction of the
arrows.
[0015] FIG. 5 is an enlarged fragmentary top view of the exit end
of the conveyor illustrating the conveyor belt centered on the
conveyor.
[0016] FIG. 6 is the same view as FIG. 5 only illustrating the
conveyor belt located off center relative to the conveyor.
[0017] FIG. 7 is a fragmentary cross-sectional view of the right
end of the centering roller of FIG. 6 illustrating the skewed
position of the roller and the deformation of the bladder.
[0018] FIG. 8 is the same view as FIG. 2 only showing the fifth
alternate embodiment of the centering roller.
[0019] FIG. 9 is a cross-sectional view taken along the line 9-9 of
FIG. 8 and viewed in the direction of the arrows.
[0020] FIG. 10 is a side view of the outer mount.
[0021] FIG. 11 is a side view of the inner hub, bladder and
bearings.
[0022] FIG. 12 is a fragmented top view of a metering roller
located adjacent an impression roller showing the preferred
embodiment of the present invention.
[0023] FIG. 13 is the same view as FIG. 12 only illustrating one
end of the axle for the metering roller being located closer to the
impression roller as compared to the opposite end of the axle.
[0024] FIG. 14 is an end view of the rollers of FIG. 13.
[0025] FIG. 15 is the same view as FIG. 12 only illustrating a
ductor roller positioned adjacent the impression roller and
utilizing the first alternate embodiment of the present
invention.
[0026] FIG. 16 is a top view of the axle and bladder positioned
within the ductor roller shown in FIG. 15.
[0027] FIG. 17 is a fragmented side view of a roller incorporating
the second alternate embodiment of the present invention.
[0028] FIG. 18 is an end view of the roller of FIG. 17.
[0029] FIG. 19 is the same view as FIG. 18 only showing the roller
mis-aligned.
[0030] FIG. 20 is a side view of a roller incorporating the third
alternate embodiment of the present invention.
[0031] FIG. 21 is an end view of the roller of FIG. 20.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended, such alterations and further modifications in the
illustrated device, and such further applications of the principles
of the invention as illustrated therein being contemplated as would
normally occur to one skilled in the art to which the invention
relates.
[0033] Referring now more particularly to FIG. 1, there is shown
the fourth alternate embodiment of the present invention including
a conveyor 20 having an endless conveyor belt 21 with a first loop
end 22 and opposite second loop end 23 forming respectively the
entrance 24 and exit 25 of the conveyor. Articles resting atop belt
21 are conveyed from the conveyor entrance 24 to the conveyor exit
25 in the direction of arrow 26. A plurality of conventional
rollers 27 are rotatably mounted to the conveyor frame 28. Rollers
27 extend across in perpendicular fashion to the direction of
travel 26 with belt 21 extending around the rollers.
[0034] Roller 29 located at loop end 22 may be connected to a
conventional drive mechanism to cause the conveyor to rotate in a
clockwise direction as viewed in FIG. 1. At the opposite end 23 of
the conveyor is located a belt centering device 30 for
automatically centering belt 21 with respect to the conveyor and
rollers 27.
[0035] Belt centering device 30 (FIG. 2) includes a belt-centering
roller 31 having an axis of rotation 32 extending longitudinally
through the center of the roller. Axis 32 extends perpendicular
across the direction of travel 26 (FIG. 1).
[0036] Roller 31 has an outer circumferentially extending
cylindrical surface 33 (FIG. 3) with belt 21 being in contact with
surface 33 as the belt extends across the top 39, side 40, and
bottom 41 of the roller. Belt 21 extends around roller 31 through
an angle of approximately 180 degrees as the belt extends from top
39 to bottom 41 of the roller. The belt is in continuous contact
with the roller between the top portion 39 of the roller and bottom
portion 41 with the belt being in contact with approximately
one-half of the circumferential surface 33 as the belt extends
around the roller.
[0037] Roller 31 is hollow having a pair of opposite end portions
34 and 35 rotatably mounted respectively to axles 42 and 43. Axles
42 and 43 are respectively fixedly secured to upstanding brackets
36 and 37 (FIG. 2) mounted atop plate 38, in turn, fixedly secured
to frame 28.
[0038] Each end portion 34 and 35 is recessed and receives a
conventional bearing rotatably receiving a bladder housing. An
inflatable fluid pressurized bladder is located within the bladder
housing and, in turn, is sealingly mounted to the axle. End portion
35 (FIG. 4) will now be described it being understood that an
identical description applies to end portion 34.
[0039] End portion 35 includes a recess 45 in which are located a
pair of spaced apart bearings 46 and 47 each extending around the
longitudinal axis 32 of the roller. Bladder housing 48 includes a
pair of side portions 49 and 50 aligned with bearings 46 and 47 and
extends around axis 32. A conventional snap ring 65 is removably
mounted to continuous recess 66 in end portion 45. Recess 66
extends continuously around axis 32 allowing the C-shaped snap ring
65 to be inserted therein immediately adjacent bearing 47 thereby
holding the bearings, bladder housing and bladder in place. Ridge
51 of housing 48 projects between bearings 46 and 47 spacing the
bearings apart. A continuous recess 52 opens inwardly towards axis
32 and is positioned between side portions 49 and 50 to receive a
fluid pressurizable bladder 53.
[0040] Bladder 53 is donut shaped having a central hole 54 through
which axle 43 extends. Bladder 53 flares outwardly surrounding hole
54 and is sealingly clamped to axle 43 by a pair of wire clamps 55
and 56. Bladder 53 extends completely around axis 32 and projects
into recess 52.
[0041] Axle 43 includes a fluid passage 57 extending from the end
58 of the axle to location 59 whereat the passage opens into
bladder 53 allowing control of the fluid pressure within the
bladder.
[0042] End portion 34 includes a bladder 63 identical to bladder 53
with bladder 63 being mounted to axle 42 by wire clamps and
contained within a bladder housing, in turn, bearingly received by
bearings provided in end portion 34 in a manner identical to that
previously described for end portion 35. Axle 42 includes a passage
64 identical to passage 57 to allow control of the fluid pressure
within bladder 63.
[0043] A pair of fluid lines 60 and 61 (FIG. 2) are connected
respectively to passages 64 and 57 with the opposite ends of lines
60 and 61 connected to a conventional fluid pressure valve 62, in
turn, connectable to a source of fluid pressure. Lines 60 and 61
are in fluid communication with each other thereby equalizing the
fluid pressure within each line and also equalizing the fluid
pressure within bladders 63 and 53.
[0044] In operation, roller 31 is freely rotatably upon axles 42
and 43 which are stationary. Likewise, bladders 53 and 63 along
with the respective bladder housings do not rotate.
[0045] FIG. 5 illustrates conveyor belt 21 extending around roller
31. With conveyor belt 21 moving in the direction of arrow 26,
roller 31 is caused to rotate in the direction of arrow 70 about
axis of rotation 32 with belt 21 being located equidistant between
the opposite ends of the roller at the same time the bladders are
not distorted and remain as shown in FIG. 4.
[0046] In the event belt 21 becomes off center with respect to
roller 31 as illustrated in FIG. 6, the belt will move closer to
one end of the roller than the opposite end. For example, belt 21
is shown in FIG. 6 as being closer to end 35 as compared to end 34
of roller 31. As the belt shifts to the right as viewed in FIG. 6,
the belt exerts force on roller 31 to cause end 35 to move toward
the opposite end or entrance end of the conveyor with end portion
34 of roller 31 moving in the opposite direction. At the same time,
axles 42 and 43 are held stationary in brackets 36 and 37 (FIG. 2).
Thus, bladders 53 and 63 are squeezed from their normal position
depicted in FIG. 4 to a cocked position depicted in FIG. 7 as the
roller cocks relative to axles 42 and 43.
[0047] Fluid pressure within the bladders remain equal and constant
causing the cylinder to revert back from the cocked position of
FIG. 7 to its original position of FIG. 4 with the central axis of
cylinder 31 being coincident with the axis extending through axles
42 and 43. As cylinder 31 moves to its original uncocked position
relative to the axles, the belt moves back to its original position
located equidistant between the opposite ends of the cylinder.
Thus, the supporting structure including axles 42 and 43, bladders
63 and 53 and the bladder housings provide a supporting structure
or means to normally urge the belt centering roller away from the
skewed position of FIG. 6 to the perpendicular position relative to
the direction of travel 26 illustrated in FIG. 5 thereby centering
the belt on the roller and on the conveyor.
[0048] The fifth alternate embodiment of the present invention
includes a web-centering roller illustrated in FIGS. 8-11.
Centering roller 130 operates in the manner identical to the
operation of roller 30. Centering roller 130 includes a cylindrical
main body 131 with opposite end portions 134 and 135 rotatably
mounted to a pair of upstanding brackets 136 and 137, in turn,
mounted to a plate affixed to frame 28 (FIG. 1). A pair of fluid
lines 160 and 161 are connected to a fluid pressure valve 162, in
turn, connected to a source of fluid pressure with the opposite
ends of the lines connected through the mounting brackets to
bladders positioned externally of the cylindrical main body
131.
[0049] End 134 of centering roller 131 will now be described it
being understood that an identical description applies to end 135.
End 134 includes an outer mount or hub 140 fixedly mounted to the
upstanding bracket 136. Mount 140 may be secured to bracket 136 by
means of welds or other conventional fastening means.
[0050] Mount 140 is hollow and receives an inner hub 141 having a
bladder 142 mounted thereto. Bladder 142 extends continuously
around recess 143 of hub 141 and includes a fluid communication
line 149 extending through bracket 136 and connected to line
160.
[0051] Hub 141 has a hollow center 145 in which is located
conventional ring shaped bearings 146 into which an end of cylinder
131 projects. The end 134 of roller 131 has a reduced diameter to
project into bearing 146 thereby rotatably mounting roller 131 to
the hub. Hub 141 and bladder 142 float within outer hub 140;
however, the fluid pressurized bladder 142 keeps the hub in place
relative to mount 140 thereby preventing relative rotational motion
therebetween.
[0052] In operation, movement of the belt across the top, side and
bottom surface of roller 131 causes the roller to rotate within the
bearings receiving the opposite ends of the roller. At the same
time, the hub 141, bladder 142 and mount 140 and the hub and
bladder within mount 150 do not rotate. Outer mount 150 is
constructed identically to mount 140 and contains an identical hub
and bladder as compared to hub 141 and bladder 142.
[0053] Centering roller 130 operates in a manner identical to
roller 30 even though the bladders are located externally of roller
131 as compared to the bladders located internally in roller 31.
Thus, as the belt moves toward the right end of roller 131 as
viewed in FIG. 8, the end portion 135 of roller 131 will move
toward the entrance of the conveyor while the opposite end portion
134 of the roller moves in an opposite direction thereby deforming
each bladder as previously described and illustrated in FIG. 7. The
bladders temporarily deform or distort by the bladder side walls
stretching and collapsing from their original shapes. For example,
bladder 53 is shown in FIG. 7 as having a right side wall in a
partially collapsed condition while the left side wall is shown as
stretched from its original position of FIG. 4. Since the fluid
pressure within the bladders positioned adjacent the opposite ends
of roller 131 is equal and constant due to lines 160 and 161,
roller 131 is urged back to its original position extending
perpendicularly across the direction of travel 26 thereby
re-centering the belt on the roller.
[0054] As roller 131 tilts or assumes a skewed position relative to
its original axis of rotation that was perpendicular to direction
26, the bladders within the inner hubs squeeze and deform as
illustrated in FIG. 7 for the first embodiment. At the same time,
the hubs within mounts 140 an 150 positioned externally of the
roller 131 also assume a cocked or skewed position thereby
resulting in the temporary deformation of the bladders.
[0055] The preferred embodiment of the present invention is shown
in FIGS. 12-14. A conventional roller 200 has a cylindrical outer
surface 201 spaced apart from a metering roller 202 having a
cylindrical outer surface 203. The opposite ends of roller 200
include a pair of axles 204 and 205 rotatably received respectively
by conventional bearings 206 and 207, in turn, fixedly secured to
respectively, frame members 208 and 209. Metering roller 202 is
operable to meter liquid 233 (FIG. 14) positioned between rollers
202 and 200 and located above the axis of rotation of each roller.
The spacing between rollers 202 and 203 will determine the amount
of liquid 210 or ink that is metered onto the impression
roller.
[0056] Metering roller 202 is rotatably mounted to an axle 210
extending the length and along the center longitudinal axis 211 of
roller 202 and axle 210. FIG. 12 is fragmented to illustrate axle
210 extending through roller 202. A pair of conventional
cylindrical bearings 212 and 213 are held captive respectively at
the opposite ends 214 and 215 of roller 202 by snap rings and
surround axle 210. Located between the axle and the interior
bearing race are a pair of pressurized bladders 216 and 217.
Bladder 216 surrounds the end portion 218 of axle 210 and is
positioned between the axle and the interior race of bearing 212.
Likewise, bladder 217 surrounds the opposite end portion 219 of
axle 210 and is positioned immediately adjacent and inward of the
inner race of bearing 213. With axle 219 fixed, the outer cylinder
202 is free to rotate on bearings 212 and 213 and with respect to
axle 219. Pressurization of bladders 216 and 217 control movement
of the outer cylinder with respect to axle 219 and thus cylinder
201. Further, the bladders absorb shock around the bearings
extending the life of the bearings and the journals.
[0057] The opposite ends of axle 210 are mounted in a pair of
upwardly extending flanges that have bottom ends pivotally mounted
to the frame members 208 and 209. For example, flange 220 (FIG. 14)
has a bottom end 221 pivotally mounted to frame 209 and a top end
222 receiving the reduced diametered end 223 of axle 210. The
opposite reduced diametered end 224 of axle 210 is received by
flange 225 in the same manner as described for end 223 and flange
220.
[0058] A pair of pneumatic cylinders 226 and 227 are mounted
respectively to frames 209 and 208 and have an extendable piston
rod attached to flanges 220 and 225. For example, pneumatic
cylinder 226 has an extendable piston 228 attached by bracket 229
to the mid-point of flange 220. Each flange 220 and 225 may be
pivoted about their bottom ends when caused to move by axle 210
moving toward cylinder 200. Each flange 220 and 225 is restricted
in pivotal movement by a pair of stops located on either side of
each flange. For example, a pair of flanges 230 and 231 are fixedly
mounted to frame 209 and contact the opposite edges of flange 220
as the flange pivots from a forward position to a rearward
position. That is, with axle 210 moving to its extreme forward
position toward roller 200, the edge of flange 220 will contact
stop 231 preventing further movement of the flange and axle.
Likewise, movement of the axle in an opposite direction will cause
flange 220 to contact flange 230 limiting the rearward movement of
the flange and axle. A guide rod 238 has opposite ends fixedly
attached to flanges 230 and 231 with rod 238 extending through
flange 240 attached to flange 220 guiding the flange as it moves
between stops, A pair of stops identical to stops 230 and 231 are
mounted fixedly to frame member 208 and have a guide rod extending
therebetween and through flange 225 to guide flange 225 and control
its forward and rearward movement with respect to roller 200.
[0059] Initially, equal fluid pressure is applied to cylinders 226
and 227 positioning axle 210 equidistant from roller 200 along the
length of the axle. Likewise, equal fluid pressure is applied to
each bladder 216 and 217 causing the roller 202 to be centered with
respect to axle 210 thereby positioning cylinder 202 equidistant
from cylinder 200 along the length of cylinder 202.
[0060] During the initial setup, it is possible that the operator
will pressurize cylinders 226 and 227 in such a manner that axle
210 and its longitudinal axis 211 may not be parallel to cylinder
200. Likewise, it is possible during operation that axle 210 may
become skewed with respect to cylinder 200. That is, it is possible
that sometime during either the initial setup or during use of the
metering roller, axle axis 211 may become skewed with respect to
the longitudinal center axis 230 of roller 200. In either case,
bladders 216 and 217 are operable to position surface 203
equidistant from surface 201 along the length of cylinder 202 or in
the event the surfaces 203 and 201 are in contact, bladders 216 and
217 are operable to maintain a constant pressure of surface 203
against surface 201.
[0061] As an example, end portion 218 of axle 210 is shown in FIG.
13 as being closer to roller 200 as compared to end portion 219 of
axle 210. Thus, flange 220 including its arm 240 affixed thereto
has contacted stop 231 preventing further movement of the axle end
portion 218 towards roller 200. Bladders 216 and 217 each include
the same pressure existing in the bladder as during its initial
setup illustrated in FIG. 12. Bladder 216 has a portion 241 located
between axle 210 and the inner race of bearing 212 and on the side
closest to roller 200 that has been reduced in size being squeezed
between the axle and the inner race. The remaining portion 242
located rearwardly of the axle has increased in size thereby
maintaining a constant pressure within the bladder and a constant
pressure exerted against bearing 212 and thus a constant pressure
between roller surface 203 and roller surface 201. Likewise, the
pressure within bladder 217 is the same as within bladder 216.
Thus, the pressure exerted by roller surface 203 against roller
surface 201 at ends 243 and 244 is constant and equal and also
along the length of roller 202 even though the axis 211 of the axle
has become skewed relative to axis 230 of the impression
roller.
[0062] The first alternate embodiment of the present invention is
shown in FIGS. 15 and 16. An impression roller 200 is mounted to
the frame member in a manner identical to that described previously
for the preferred embodiment of FIG. 12. Ductor roller 250 is
mounted next to roller 200. A ductor roller is subject to constant
banging against an impression roller and thus, any bladders located
within the ductor roller will have considerably more abuse as
compared to the bladders within metering roller 202. Thus, the
bladder utilized with the first alternate embodiment of FIGS. 15
and 16 extends wrappingly and spiralingly around the length of the
axle 251 with only a single bladder utilized. The bladder is
attached through the shaft at one end and plugged at the opposite
end of the bladder tube.
[0063] Axle 251 (FIG. 16) in the first alternate embodiment
includes a one-quarter inch outside diameter copper tube 257 that
extends through the center of end portion 252 of the axle. One end
of the copper tube is attached to a compression fitting 253 whereas
the opposite end is connected to end 254 of bladder 255. Bladder
255 extends spiralingly around axle 251 and is closed by plug 260
at its opposite end 259. Axle 251 includes a recess 256 opening
into the center passage of the axle through which tube 257 extends.
Thus, copper tube 257 does not extend outwardly of the outer
surface of the axle and is positioned within recess 256 while being
in fluid communication with bladder 255. Likewise, a second recess
258 is provided at the opposite end of the axle to locate plug 260
within the outside surface of the axle. Plug 260 sealingly closes
end 259 of the bladder tube.
[0064] The opposite end portions 252 and 260 of axle 251 are
mounted and controlled in an identical manner to the opposite end
portions of axle 210. Thus, a pair of pneumatic cylinders 226 and
227 are provided along with the associated steps and flanges 220
and 225 previously described for the preferred embodiment of FIG.
12. Compression fitting 253 may either sealingly close the bladder
maintaining a constant fluid pressure within bladder 255 or may be
connected to a source of pressurized fluid to maintain the fluid
pressure at a constant level within the bladder.
[0065] Bladder 255 may extend substantially along the entire length
of axle 251 so as to be positioned between bearings 212 and 213 in
a manner similar to that described for the preferred embodiment of
FIG. 12. Alternatively, bladder 255 may extend around axle 251 from
one bearing to the opposite bearing without extending between the
inner race of the bearing and the axle.
[0066] The ductor roller operates in a manner identical to the
operation previously described for metering roll 202. Thus, if the
longitudinal axis of axle 251 becomes skewed with the longitudinal
axis of roller 200, the pressure within bladder 255 is operable to
maintain a constant and equal force of ductor roller 250 against
impression roller 200. For example, if a portion of axle 251 moves
closer to impression roller 200 then the bladder will be squeezed
at the location of the axle moving closer to the impression roller;
however, the pressure within the bladder will remain constant at
that particular location maintaining constant pressure of roller
250 against roller 200.
[0067] A second alternate embodiment of the present invention is
shown in FIGS. 17-19. The roller and bladder shown therein is used
in the conveyor assembly depicted in FIG. 1 and replaces belt
centering device 30 for automatically centering belt 21 with
respect to the conveyor and rollers 27.
[0068] Roller 270 includes a pair of opposite reduced diameter ends
271 and 272 rotatably mounted in upstanding arms 273 and 274; in
turn, fixedly mounted atop a downwardly extending L-shaped bracket
275. Bracket 275 is bolted and pivotally supported by fastener 277
to an upwardly extending L-shaped bracket 276. Conveyor belt 21
(FIG. 18) extends around the cylindrical surface of roller 270 that
includes a pressurized bladder positioned between L-shaped brackets
275 and 276 for automatically centering the belt on roller 270.
Fastener 277 is a standard bolt nut combination extending through a
spacer positioned between and against the horizontally extending
flanges 279 and 280 respectively of brackets 275 and 276. The
spacer and fastener allows bracket 275 to pivot about the
longitudinal axis of fastener 277 while L-shaped bracket 276
remains fixed to the conveyor frame.
[0069] A single pressurized bladder 281 (FIG. 19) has a first end
282 either sealed or connected to a source of constant fluid
pressure. The opposite end 284 of the bladder is sealed. Bladder
281 is positioned between the horizontal walls 279 and 280 of the
L-shaped brackets and is also positioned between the vertically
extending walls 286 and 287 (FIG. 18) of the L-shaped brackets. By
maintaining a constant fluid pressure within bladder 281, roller
270 is forced to its perpendicular position relative to the
conveyor belt. As the conveyor belt 21 tracks off center relative
to roller 270, a force is created to one end of roller 270 causing
the other end of the roller to be forced in the opposite direction
thereby forcing the conveyor to track back to the center of the
roller. For example, if end 290 (FIG. 19) of roller 270 moves
toward the opposite end 22 (FIG. 1) of the conveyor while end 291
moves in the opposite direction, brackets 275 and 276 will squeeze
the end portion 284 of bladder 281 causing the bladder to expand
adjacent end 282 of the bladder. The pressure within the bladder is
constant thereby causing end portion 284 of the bladder to then
expand towards its original size forcing fluid flow in the
direction of arrow 293 and allowing end portion 290 of the roller
to move away from the opposite end 22 of the conveyer towards its
original position centering the conveyor upon roller 290.
[0070] A pair of semi-cylindrical projections 294 and 295 are
fixedly mounted to wall 287 of L-shaped bracket 276 to increase the
sensitivity of the bladder by reducing the amount of space through
which bladder 281 extends.
[0071] A third alternate embodiment of the conveyor belt roller is
shown in FIGS. 20 and 21 and is identical to the second alternate
embodiment of FIGS. 17-19 with the exception that a pair of
bladders are utilized between a pair of opposed C-shaped
brackets.
[0072] Roller 300 has reduced diametered opposite ends 301 and 302
mounted by conventional bearings to upstanding flanges 303 and 304
fixedly mounted to wall 305 having two pairs of downwardly
extending walls 306 and 307 depending from and attached to wall
305. An upwardly extending C-shaped bracket 317 is pivotally
mounted to wall 305 by means of the fastener 277 and spacer 278
previously described for the embodiment of FIGS. 17-19. Bracket 307
includes a pair of upstanding walls 308 and 309 spaced outwardly of
the two pairs of downwardly extending walls 306 and 307 with a pair
of fluid bladders 310 and 311 positioned therebetween. Thus, wall
pair 307 consists of two walls 312 and 313 extending downwardly on
either side of spacer 278 with wall 312 being spaced from wall 308
between which bladder 310 is located and wall 313 being spaced
apart from wall 309 between which bladder 311 is positioned.
[0073] Likewise, pair 306 includes a pair of downwardly extending
walls on either side of spacer 278 being spaced apart from walls
308 and 309. Bladder 310 extends between wall 308 and one of the
walls of pair 306 in a manner identical to bladder 310 extending
between wall 308 and wall 312. Bladder 311 extends between wall 309
and the other wall of pair 306 in a manner identical to bladder 311
extending between wall 309 and wall 313. Bladder 310 includes a
fluid fitting 312 whereas bladder 311 includes fluid fitting 313.
Fittings 312 and 313 may sealingly close each bladder thereby
maintaining the pressure within each bladder. Alternatively, each
fitting may be connected to a source of pressure to maintain the
pressure within each bladder.
[0074] Roller 300 operates identical to the operation of roller 270
with the exception that a pair of bladders are used instead of a
single bladder. As the conveyor belt 21 tracks off center relative
to roller 300, a force is created at one end of the roller causing
the other end of the roller to be forced at equal pressure in the
opposite direction thereby causing the conveyor belt to track back
to the center of the roller. The two fluid bladders respond as
cushions to absorb rapid changes in the belt that may be caused
when items are placed upon the belt for conveyance thereby
preventing oscillation and overshoot of the belt. With the fluid
supply regulated to each bladder 310 and 311, increasing or
decreasing the pressure in each bladder can control the belt
tracking correction response. Alternatively, each bladder is sealed
from each other maintaining a constant pressure in each
bladder.
[0075] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiments have been
shown and described and that all changes and modifications that
come within the spirit of the invention are desired to be
protected.
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