Note: Descriptions are shown in the official language in which they were submitted.
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AI)JUSTABL~ LENGTH CONVEYOR ~YSTEM
Tcchnical Fiel~l
Thi.c inveD~ion pertaini to the art uf mc~hods and apparatuses f~ r adjustin~ th~ len~th of
5 a conveyor sy.~cm to compensate for chan~es ~n the Icngth of a strip material caus~d by
in~crmitteslt teedin~ or by changes in specd of recdin~, and morc spec:ifically lO methods and
aI~palaluscs for supporting the strip rnatcrial in a ~cnerally h~nzontal attitu~le during lhc len~lh
a~ stmen~.
Back~roun-:l Art
lUIn the ~ast, vertical testoons were u~ed t-) adju~ thc length of ~ cnnv~yor system ~o
comperlsate f~)r iL~ Ltent feedin&r ~. r strl~ ~tcrial ~ mcet variable produc~ion re~luircmenls.
~owever, when vertiea] fest~aons wer~ uscd, thc strip material was no~ suppor~ed and was
stre~chcd by its own wei~ht. rhi.c stretching of lhc strip material was nnt desirable when
assembling a product su~h as a tire. Onc sueh conveyor of s~ mat~rial ~s found in U S. ~atent
15No. 4,892.60~ to l~rakanome et a~., which dicclos~; an aut~matic material feedcr i~ tirc forming
ma~;hincs. Thc rna~:hinc has a ~raditional vertical festuon to supE~nrt the buildup o~ tire buildin~
materials. In Europ~an Patem EP-A-0 464 862 cnnvcy(lr~ 76 an~l 78 are movab1e, however, no
prn~ision of a festo(~n for !;loring maLerial is made. Al~n in U.~S. Patent No. ~rS-AS,451,nl 1 loop
detecth~g mealls are r~rovided for st~el nr a1~ u~ s~rip un~ilin~ apparan~s whcre no support
'Oot dl~ c.~rip i~ ~se~tial.
When e~lnVeyors of a stri}~ matenal did n~1~ have f~an~res to compensatc for c:hange~ in
len~th Or dlc stnp material cause~ hy inte.")ilL~,Lt fe~ding, e~lruders, for exa~ lc, would have
to b~ ct~pped and starled to ~.ll~xn~at~ for the chan~es in fceding. This ~tar~ing and stopping
may pr~uce undcsirable variations in the .c~rip m~erial.
25~pp]ieants rec~ xnizcd th~ nccd to provlde an adjustmerlt app~ra~us ~nd method ~hat did
not stretch the s~ rial and did n~t pro~ucc or a~l~l additional stresses to the ~tritl mat~rial.
Thc pres~nl invenuon contcsnpl~les a new ;~nd improved ad~ mcnt for a convey-)r systenl
which is siml~lc in ~sign, cffectivc in use. and overcomes tJ~e fore~in~ difficulties and nthers
whilc provi(ling better and more adYantageous overall result!;.
3()Di~clo~urc af Inv~ndon
ln accorda~c~ with the pre.sen~ invention, a ucw and improved adjustahlc substantially
hor~zontal ~:onvcvar is pmvided whi-:h co~ n~1Pc for the chan~es in length ~)f thc strip rnatcrial
bein~ conve~yed 2S a resull of in.~ tent f~edin~ without a]lering the weight or .sha~e of the strip
m~leriah
A~"7c~JDLD S~ET
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1~
M~re particularly, in accord.~n~e with ~hc ~rcsent invention, ~ conYey~r asscn~bly for
conYcying and storin~ an associated strip material in a convey~r syslem is prol.~ided~ Thc
conveyor assemhly incl1~dcs an UE~er convcyor fur rccciving ~nd u~nv~yu~ thc associ~te~ stnp
matcrial. The upper conveyor has a first u-nvcyor t)el~ and a first ~Invine, means ~or drivin~T
s
1()
'S
AMEND.3 S.~:~ET
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the first conveyor belt. The upper conveyor is substantially stationary. A center conveyor
receives the associated strip material from the upper conveyor, and has a second conveyor belt
and a second driving means for driving the second conveyor belt. The center conveyor is
movable along a substantially ho,i~ol,lal path and has length adjusting means for moving the
S center conveyor along the path. A lower conveyor is provided for receiving the associated
strip material from the center conveyor, and has a third conveyor belt with a third driving
means for driving the third conveyor belt. The lower conveyor is substantially stationary.
According to one aspect of the present invention there is provided a length adjusting
conveyor for storing a variable length of strip material in a conveyor system including supply
means for supplying the associated strip material to the length adjusting conveyor with the
length adjusting conveyor having a conveyor belt and driving means for driving the conveyor
belt, the length adjusting conveyor being movable along a substantially horizontal path; power
means for moving the length adjusting conveyor along the path; and, take away means for
receiving the ~csoci~ted strip material from the length adjusting conveyor.
According to another aspect of the present invention there is provided a method of
conveying an associated strip material along a conveyor assembly wherein the conveyor
assembly includes an upper conveyor having a first conveyor belt and a first driving means, a
center length adjusting conveyor having a second conveyor belt and second driving means, and
a lower conveyor having a third conveyor belt and third driving means, the method including
the steps of: conveying the associated strip material along the upper conveyor in a first
direction with the first driving means; transferring the associated strip material to the center
length adjusting conveyor; moving the center length adjusting conveyor along a substantially
horizontal path to adjust the length of the conveyor assembly in response to changes in length
of the associated strip material; conveying the associated strip material along the center length
adjusting conveyor in a second direction opposite the first direction with the second driving
means; transferring the associated strip material to the lower conveyor; and, conveying the
associated strip material along the lower conveyor in the first direction with the third driving
means.
According to another aspect of the present invention there is provided a method of
adjusting the length of a conveyor system to compensate for changes in the length of an
associated strip in a conveyor system, the conveyor system having a length adjusting conveyor
with a conveyor belt and driving means, supply means, and take away means, the method
including the steps of: supplying the associated strip material to the length adjusting conveyor
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with the supply means; moving the length adjusting conveyor in a subs~nti~lly horizontal
direction in response to changes in length of the associated strip material in the conveyor
system; conveying the associated strip material along at least a portion of the length adjusting
conveyor with the driving means; and, transferring the associated strip material to the take away
S means.
One advantage of the present invention is that the conveyor system may adjust for
variable lengths of the strip material in the system caused by different supply and take away
speeds including stoppage at the takeaway position.
Another advantage of the present invention is that the conveyor system adjusts for
10 changes in the length of the strip material in the system without çh~nging the stresses on the
strip material.
Still other benefits and advantages of the invention will become apparent to those ski!led
in the art to which it pertains upon a reading and underst~nding of the following detailed
specification.
Brief Description of Drawings
The invention may take physical form in certain parts and arrangement of parts, a
preferred embodiment of which will be described in detail in this specification and illustrated
in the accompanying drawings which form a part hereof and herein:
Figure 1 is a schem~tic side elevation of a conveyor assembly embodying the invention
showing the center conveyor in the retracted position;
Figure 2 is a sch~m~tir side elevation of the conveyor assembly of Figure I with the
center conveyor in the extended position;
Figure 3 is an enlarged fragmentary view of part of the center conveyor showing a
preferred embodiment of the present invention utilizing a proximity switch; and,Figure 4 is a schematic side elevation of the conveyor assembly of Figure 1 with a
proximity switch at the end of the center conveyor and the upper conveyor.
Detailed Description of the Invention
Referring now to the drawings wherein the showings are for purposes of illustrating a
preferred embodiment of the invention only and not for purposes of limiting the same, Figure
I shows a schematic view of a conveyor assembly 10 embodying the system of the invention.
The conveyor assembly 10 preferably has an upper conveyor 16, a center conveyor 22, and a
lower conveyor 28. A strip material 34 of rubber or other deformab]e material is conveyed by
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the conveyor assembly 10 from a supply position 40, such as from an extruder, along a path
44 to a take away position 46, for feeding the strip material to apparatus such as a strip
applicator. The strip material 34 is conveyed from the supply position 40 over the upper
conveyor 16 in the direction of arrow A by a conveyor belt 52 driven by a first servomotor 58.
The strip material 34 is then transferred to the center conveyor 22, preferably by allowing the
strip material to fall over an end 60 of the upper conveyor 16 onto the center conveyor where
the strip material is moved in a reverse direction as shown by arrow B. The strip material 34
is turned over and is conveyed on the center conveyor 22 on a conveyor belt 64 driven by a
second servomotor 70. At a leading end 72 of the center conveyor 22, the strip material 34 is
then transferred to the lower conveyor 28, pre~e,ably by allowing the strip material to fall over
the end of the center conveyor onto the lower conveyor where the strip material again reverses
direction in the direction of arrow A and is turned over to the same position as it was on the
upper conveyor 16 so that it is right side up. The lower conveyor 28 conveys the strip material
34 in the direction of arrow A along a conveyor belt 76 driven by a third servomotor 82 to the
take away position 46.
The upper conveyor 16 conveys the strip material 34 at an upper conveyor speed Sl that
equals the speed at which strip material is provided at the supply position 40. The lower
conveyor 28 conveys strip material 34 at a lower conveyor speed S2 that equals the speed at
which the strip material is taken away at the take away position 46. When speed Sl equals
speed S2, the center conveyor 22 conveys strip material 34 at a speed S3 that is equal to speed
S1 and speed S2. When the demand for the strip material 34 at the take away position 46
decreases, such as when the feeding of the strip material application is intermittent, or
decreased, the speed S2 is decreased. If speed S1 of the upper conveyor 16 cannot be adjusted
to conlpensate for the decrease in speed S2, then the strip material 34 will back up along the
conveyor assembly 10. In the preferred embodiment of the invention, a computer 94 is used
to control the servomotor 70 that drives the center conveyor belt 64. The center conveyor 22
may be supported on a frame which is mounted on a servomech~nicm 100 such as a belt driven
liner actuator having â servo motor to move the frame and supported center conveyor back and
forth substantially ho- i~onl~lly~ in the directions of arrows A and B. If the speed S 1 is different
than the speed S2, then colllpuler 94 preferably directs servomotor 70 to rotate the center
conveyor belt 64 at a speed S3 that is equal to the average of speeds Sl and S2 or one half of
the sum of speeds S1 and S2. Computer 94 is also connected to the servomechanism 100 which
moves the center conveyor 22 at a speed S4 that is equal to one half of the difference between
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speed S3 and speed S2. If speed S3 is greater than speed S2, the center conveyor 22 is moved
in the direction of arrow B. If speed S2 is greater than the speed S3, then the center conveyor
22 is moved in the direction of arrow A. The speed S4 at which the center conveyor 22 is
moved is predetermined for the condition where S2 is zero between feeding of the strip material
34 and where S2 is greater than S1, during the feeding of the strip material. Additionally, an
optical sensor 88 is placed near the end 72 of the center conveyor 22 to detect whether a loop
90, shown in dotted lines, is formed by decreased tension in the strip material 34 due to the
speed S2 of the lower conveyor 28 being less than the speed S1 of the upper conveyor, and
when the computer 94 has not made a correction for the decreased tension in the strip material.
If such a loop 90 is det~cted the computer 94 receives a signal from the optical sensor 88 and
in response causes the seNom~rh~ni~rn 100 to move the center conveyor 22 for a predetermined
time in direction B to adjust the length of the strip material 34 by picking up the slack in.the
strip material.
Figure 2 shows a schematic view of the conveyor assembly 10 with the center conveyor
22 moved to the right and acting as a length adjusting conveyor by increasing the length of the
path 44 to accommodate the increased length of the strip material 34 in the system as the strip
material is moved along the conveyor assembly 10. In Figure 2, the servomech~ni~m 100 has
moved the center conveyor 22 in the direction of arrow B at the direction of the computer 94
or after the sensor 88 detected a loop 90. This movement has increased the length of the path
44 to compensate for the increased length of the strip material 34 in the system and allows the
conveyor assembly 10 to support the strip material without increasing the tension in the strip
material. This is particularly important for materials such as extruded rubber that are
susceptible to deformation under tension.
With further reference to Figures 1 and 2, when a loop 90 is dete~ted by the optical
sensor 88 which is in commllnir~tion with the computer 94, signals are conveyed from the
computer to the servomech~ni~m 100 preferably to move the center conveyor 22 at a speed S4
that is one half the difference between speed S3 and speed S2. The center conveyor 22 is
moved in the direction of arrow B if speed S2 is less than speed S3, and the center conveyor
is moved in the direction of arrow A if speed S2 is greater than speed S3. When the sensor 88
no longer detects a loop 90 in the strip material 34, the computer 94 conveys signals to
servomechanism 100 to move the center conveyor 22 in the direction of arrow A. If a loop 90
is again detected in the strip material 34 by the sensor 88, the computer 94 will once again
convey signals to the servomech~nicm 100 to move the center conveyor in the direction of arrow
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B. This process of moving the center conveyor 22 back and forth keeps the conveyor assembly
10 in an equilibrium position and the tension on the strip material 34 substantially constant
With reference to Figure 3, a prerel-ed embodiment of the sensor for the loop 90 is
shown in which a proximity switch 106 is disposed at the end 72 of the center conveyor 22 tO
detect the loop in the strip material 34. The proximity switch 106 includes a roller 108 attached
to a metal contact 112. The roller 108 is guided by slides 114,116 located at the sides 120,122
of the center conveyor 22. The roller 108 is pulled in direction A by the tension of the strip
material 34, and in direction B by springs 132,134 that are connected to the roller. The metal
contact 112 moves back and forth between two contacts 124,126 to form a switch. When speed
S1 is equal to speed S2, the proximity switch 106 is held in an equilibrium position, and the
metal contact is suspended between the two contacts 124,126. When the speed S1 is greater
than speed S2, a loop 90 forms around the proximity switch 106, and the tension on the roller
108 is reduced, thereby allowing springs 132,134 to pull the roller and the metal contact 112
into engagement with contact 124, and thereby closing a circuit that includes the power supply
118 and detection app~tlls 140. The detection apparatus 140 then causes activation of the
servomech~ni~m 100 (see Figure 2) to move the center conveyor 22 at a speed S4 equal to one
half the difference of speeds S3 and S2 to adjust the path 44 of the strip material 34 by
increasing the length of the path of the strip material. If speed S2 is greater than speed S 1, then
a greater amount of tension is placed on the roller 108. The tension on the roller 108
overcomes the pull of springs 132,134 and the metal contact 112 comes into engagement with
contact 126, thereby closing a circuit that includes the power supply 118 and detection apparatus
142. The detection apparatus 142 then causes activation of the servomPch~ni~m 100 (see Figure
2) to move the center conveyor 22 at a speed S4 equal to one half the difference between speeds
S3 and S2 in direction A as shown in Figure 2 to release strip material 34 taken up by prior
movement of the center conveyor and thereby decrease the length of the path 44 of the strip
material.
With re~erence to Figure 4, a conveyor assembly 10 is shown with the proximity switch
106 at the end 72 of the center conveyor 22. Additionally, a second proximity switch 106' is
located at the end 60 of the upper conveyor 16. The second proximity switch 106' further
enables the conveyor assembly 10 to detect changes in tension in the strip material 34 by
detecting a loop 152 that forms around the end 60 of the upper conveyor 16. The second
proximity switch 106' has a roller 108', co~ 124' and 126' and is also connected to the
servomechanism 100 that controls the speed S4 of the center conveyor 22.
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With contin~ling reference to Figures 1, 2, 3, and 4, the conveyor assembly 10 may
employ more than one center conveyor 22 to increase the capacity of the conveyor assembly to
accommodate changes in the length of the strip material 34 caused by intermittent feeding of
strip material at the takeaway position 46. Each center conveyor 22 may be equipped with
either an optical sensor 88 or proximity switch 106 to detect a loop 90 in the strip material 34
at the end of the center conveyor. The strip material 34 may also be fed through the conveyor
assembly 10 to a supply position 40 along the path 44 in the direction opposite that described
heretofore. A computer may be connected to the servomP-ch,.nism~ 100 of the center conveyors
22 for controlling their movement during intermittent operation of the lower conveyor 28.
While certain representative embodiments and details have been shown for the purpose
of illustrating the invention, it will be app~elll to those skilled in the art that various changes
and modifications may be made therein without departing from the scope of the invention
Having thus described the invention, it is now c!~im~d:
