US005626804A

United States Patent (19) 11 Patent Number: 5,626,804

Benkowski et al. 45 Date of Patent: May 6, 1997
54 ROLLER POSITION CONTROLLER FOR A 4,536,649 8/1985 Kozai et al. ....................... 250/23114
CONTINUOUS BELT PRESS 4,613,293 9/1986 Gerhardt ................................. 42.5/371
4,621,999 11/1986 Gerhardt .......... ... 425/371
(75) Inventors: Frank J. Benkowski, New 4,726,871 2/1988 Hiisges et al. .......................... 156/389
Philadelphia, Ohio; Eric S. DelliGatti, 4,767,164 8/1988 Yeung ................................ 250/22721
4,870,270 9/1989 Brennan ... 250/22721
Clifton, N.Y.; David A. Kadri, West 4,923,384 5/1990 Gerhardt ................................. 42.5/371
Lafayette, Ohio 4,966,642 10/1990 Zitzmann ................................ 156/164
5,038,031 8/1991 Kurosawa et al. 250/227.28
73 Assignee: General Electric Company, 5,193,451 3/1993 Sitzler et al. ........................... 42.5/37
Coschocton, Ohio
FOREIGN PATENT DOCUMENTS
21 Appl. No.: 562,312 3940579 6/1991 Germany ............................... 42.5/371
22 Fed: Nov. 22, 1995 OTHER PUBLICATIONS

Related U.S. Application Data Siempelkamp, Siempelkamp Contiroll for Technical Lami
nates, pp. 1-5, date unknown.
62 Division of Ser. No. 84,694, Jun. 29, 1993, abandoned. Gre Con, Hydro-Dyn Double Belt Presses, pp. 1-3, Oct. 31,
1985.
51 Int. Cla. B30B 5/06; B3OB 15/26 Hymmen, The best way to produce decorative laminates in
52 U.S. Cl. ................... 264/40.5: 100/151; 250/227.21; sheet or roll form, pp. 1-2, date unknown.
264/166; 425/150: 425/371
58 Field of Search ...................... 250/227.21, 231.14, Primary Examiner-Mathieu D. Vargot
250/227.28; 264/408,409, 410, 412, 40.7, 57 ABSTRACT
40.5, 319, 320, 166: 425/135, 138, 150,
168, 371,372, 363; 100/157 The present invention provides a roller position controller
for a continuous belt press whereby the positions of the
56) References Cited rollers supporting the belts are monitored and controlled, so
that their relative positions always remain staggered and
U.S. PATENT DOCUMENTS fixed with respect to each other. By maintaining the rollers
3,354,319 11/1967 Loewen et al. .................... 250/22721 in a synchronized relationship, material defects such as
3,461,304 8/1969 Genhar et al. . ... 250/227.2 "pinching” are avoided.
4,096,383 6/1978 Mancini et al. ... 250/231.14
4,457,683 7/1984 Gerhardt et al. ........................ 425/373 15 Claims, 9 Drawing Sheets
U.S. Patent May 6, 1997 Sheet 1 of 9 5,626,804

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 5,626,804
1. 2
ROLLER POSITION CONTROLLER FOR A Since the upper and lower roller chain drive mechanisms
CONTINUOUS BELT PRESS are not mechanically connected, problems result when the
relative positions of the upper and lower chain/roller mecha
This is a continuation of Ser. No. 08/084,694 filed on Jun. nisms cannot be accurately synchronized. That is, the rollers
29, 1993, now abandoned. may travel at different speeds, resulting in a condition where
BACKGROUND OF THE INVENTION the upper and lower roller sets occasionally overlap. In
normal operation, the upper and lower roller sets are equally
Belt-type presses for making particleboard, fiberboard, spaced apart and staggered from top to bottom so that either
copper clad boards for printed circuit boards and the like are an upper or lower roller is aligned with and reach the press
known in the prior art related to the invention. The materials 10 gap entrance at a time, but never both simultaneously. For
being pressed (known as press materials or press products) example, when an upper press roller is at the press gap
can include laminates, rubber products, particleboard, plas entrance, a space between two rollers of the lower press
tics and any other products formed by pressing multiple should be aligned at that same point. In this manner, only
layers together. Generally, belt presses comprise an endless one roller (either an upper or lower roller) is contacting its
upper press belt, often a steel press belt, circulated over 15 press belt at the press gap entrance at a time. However, in the
spaced-apart guide belt rollers, and a corresponding endless absence of any mechanism to keep the upper and lower
lower press belt, also often a steel press belt, circulated over roller chains synchronized, the upper and lower roller chains
spaced-apart guide belt rollers as well. Between them, these "drift” with respect to each other, and the upper and lower
press belts form a pressing gap or pressing region of the rollers eventually overlap at the press gap entrance. That is,
belt-type press, between the press framework having upper an upper roller and lower roller can reach the press gap
and lowerplatens. The upper and lower belts each have their entrance at exactly the same moment. When this occurs, the
own drive mechanisms. In a known press of this type, two press material is "pinched” between the two rollers, and a
chains are associated with each of the press platens and press press material defect known as a barmark occurs. Barmarks
belts, or a total of four chains per belt press system. The are the result of the roller overlap at the press gap entrance,
upper and lower platens form an entrance region along a 25 and are created by high localized pressure loading. It is a
complete horizontal plane. primary objective for a belt press to fabricate press material
Into the pressing region between the platens and their without defects caused by bar marks. One solution to this
corresponding press belts, the spaced apart rollers are fed problem would be to use a single interconnected drive
and guided along a circulation path with the aid of upper and mechanism for both the upper and lower roller sets, by
lower roller circulation mechanisms. The roller circulation 30 connecting the upper and lower chain drive axes with, for
mechanisms comprise upper and lower chain sets, where example, a timing chain. That technique, however, makes
each set is driven by a chain drive sprocket. The chain sets, separation of the upper and lower presses difficult, which
in turn, circulate or drive the rollers so that the rollers move hinders maintenance and overall press versatility.
along with the press belts, situated between their respective SUMMARY OF THE INVENTION
belts and the platens. Guide rails are used to channel the 35
movement of the chain sets and rollers in the intended These objects and others which will become more appar
direction. Thus, the upper press mechanism has two chains ent hereinafter are attained in accordance with the invention
with rollers disposed across the width of the press between in a belt-type press for making particleboard, fiberboard,
both chains, and the lower press mechanism has two corre copper clad laminates for printed circuit boards,
sponding chains with rollers disposed between them as well. 40 pressedboard, laminates, and the like comprising endless
In many cases, the upper and lower platens are heated. upper and lower press belts, preferably steel press belts,
The rollers are situated between the steel press belts and the circulated over upper and lower belt guide rollers. These
heated platens. The rollers are equally spaced apart and roll upper and lower press belts are positioned to form a pressing
more or less along with the belt. As pressmaterialis inserted gap between the upper and lower press belts in a pressing
into the entrance of the pressing region (or press gap 45 region, and the press frameworkhas upper and lower platens
entrance), the steel press belts are contacted by the press as well as upper and lower roller chain drive mechanisms.
products on one side and the rollers on the other. In turn, the A plurality of rolling rods spaced apart from each other
rollers contact the press belts and the heated platens, thus are fed into the pressing region between each of the platens
acting to transfer heat from the platens to the steel belts. The and its corresponding press belt. The rollers are guided with
heat is ultimately transferred from the platen to the steel 50 a chain and guide circulating mechanism, wherein each
press belt via the rollers. Finally, the heat is transferred from roller is fastened at its ends between first and second chains,
the steel press belt to the press material. and each chain set is guided over at least one sprocket driven
For the circulation of rolling rods to the press gap by a chain drive motor. Guide rails control the movement of
entrance, the rolling rods are channeled along guide rails and the roller drive chains.
links cooperating with sliding wheels and guide wheels. 55 At the press gap entrance, the rollers are continuously
Both sets of chains, that is, the upper and lower chain sets, circulating between the platens and press belts. The platens,
are driven individually by chain drive motors. Each motoris press belts and rollers are commonly made of steel. The
connected to a chain drive axis, which has chain drive chains used to drive the rollers are known as roller drive
sprockets disposed at its ends. The upper and lower chain chains. The roller drive chains are driven by chain drive
drive systems, however, are not connected mechanically sprockets, which are connected to the ends of chain drive
because the belt press is specifically designed to open. That axles. The chain drive axles are connected to chain drive
is, the upper and lower belt press mechanisms form a “C”. motors, which drive the entire chain drive mechanism. Both
with the upper belt press as the top half of the "C", and the the upper and lower presses have a set of rollers and chains,
lower belt press as the bottom half. In this manner, the belt and both the upper and lower presses have their own chain
press system can easily be maintained, and all moving parts 65 drive motors.
are freely accessible to the operator or maintenance person According to the present invention, the relative positions
nel. of the upper and lower rollers are monitored and controlled.
 5,626,804
3 4
As described above, the chain sets are driven by sprockets. DETALED DESCRIPTION OF THE
Specifically, two sprockets are used for the upper and PREFERRED EMBODIMENT
another two for the lower set of chains. The sprockets are FIG. 1 is a side view of a continuous belt press system 10.
each fastened at each end of an axle that is driven by a chain Top exit drum 28 is driven counterclockwise and bottom exit
drive motor. These axles each rotate at a speed set by its drum 30 is driven clockwise, so that press belts 18 and 19
respective chain drive motor (one for the upper press and are driven through the press gap 21. In turn, top entry drum
another for the lower press). The sprockets drive roller 12 and bottom entry drum 16 rotate along with press belts 18
chains in response to the chain drive motors being activated. and 19. Typically, only exit drums 28 and 30 are actually
Thus, in order to sense the position of the upper and lower motor driven, while entry drums 12 and 16 are in turn driven
roller sets, that is, to ascertain when rollers reach the press 10
by their corresponding belts. Importantly, the upper press
gap entrance at any given instant in time, only the angular assembly 23 and the lower press assembly 25 have press
positions of the sprockets nearest the press gap entrance belts 18 and 19 respectively that are independently driven.
need be known. Because the rollers are mechanically In this manner, the upper and lower press assemblies can be
coupled to the chains, and the chains are disposed against separated, that is, for example, the upper press assembly 23
sprockets, the angular position of the drive sprockets is 15
can be raised without being confined by any mechanical
indicative of the position of the rollers at all times. connections to the lower press assembly 25.
According to a preferred embodiment of the present The upper press assembly 23 is raised away from the
invention, an apertured disk is fastened to the drive axle lower press assembly 25 by the activation of belt press
located at the press gap entrance and chain drive sprocket. open/close cylinder assemblies 34, which are located out of
The apertured disks revolve along with the sprockets. One the way, to the sides of press belts 18 and 19. In the
apertured disk is fastened to the upper drive axle located at manufacture of laminates, for example, the fabrication of
the press gap entrance, while another is fastened to the lower copper clad laminates for printed circuit boards, press belts
drive axle. The apertures of the upper and lower disks are 18 and 19 compress material (press material) which is
arranged such that an optical sensor keeps track of the 25 inserted into the press gap 21. Belt wiper units 14 and 32 are
movement of the upper and lower roller chains by sensing used to clean off the press belts, e.g., to remove dust and dirt
the rotation of the apertured disks. These apertured disks are that can interfere with the manufacturing process from the
also known as chopper disks, since the apertured disks are belts. The wiper units may incorporate the use of fabric to
rotated between an optical emitter and sensor, and the disks wipe off the belts. Excess fluids (e.g., lubricants) are col
chop the light beams. A programmable computer (or pro 30 lected below the belt press system 10 in fluid pan 24.
grammable logic controller ("PLC")) is used to monitor the The upper belt system 23 is connected to the lower belt
positions of the upper and lower chains, and in response to system 25 by a series of hinges and support structures, well
sensing a shift in their relative positions, sends impulses to known in the art. The lower belt system 25 is supported by
the chain drive motors to adjust their respective speeds, or support fixtures 22. The upper and lower press belt systems
at least the speed of one, so that the movement of the upper 35 23 and 25 nearly meet, so that a press gap 21 is formed
and lower roller chains can be kept in sync. In this manner, between upper press belt 18 and lower press belt 19. Friction
the positions of the upper and lower roller chains are is applied to press materials entering the press gap 21 by the
monitored and controlled so that they are synchronous, and upper press belt 18 supported by upper platen 31, and by the
therefore, the positions of the upper and lower rollers are lower press belt 19 supported by lower platen 31. Both of
never allowed to overlap, including at the point where they 40 these platens 31, often made of steel, can be heated as
reach the press gap entrance. desired. A series of rollers 62 (also often made of steel and
BRIEF DESCRIPTION OF THE DRAWINGS shown at FIG. 3) driven by a chain 48 are sandwiched
between the upper and lower press belts and their respective
FIG. 1 is a side view of a continuous belt press system. platens. These rollers 62 support the belts and facilitate their
45 movement along the length of the continuous belt press 10,
FIG. 2 is a top view of a continuous belt press system. and also serve to transfer heat from the platens 31 to the belts
FIG. 3 is a diagram of the roller drive system of the 18 and 19. The belts, rollers and platens can be composed of
bottom half of a continuous belt press. any material desired, but often, they are all made of steel. In
FIG. 4 is a cross-sectional view 4-4 taken from FIG. 3. this manner, the rollers 62 transfer heat from the platens 31
50 to the belts 18 and 19. When belts 18 and 19 are also made
FIG. 5 is a top view of the position indicator mounting of steel or other thermally conductive materials, the heat of
structure used for the lower half of a continuous belt press platen 31 is transferred to the press material being inserted
system, shown with the apertured disk. into the press gap 21.
FIG. 6 is a side view of the position indicator system, Chain guide 36 is used to guide the upper roller timing
shown with the apertured disk or chopper disk. 55 chain 48 so that the chain does not become entangles in
FIG. 7 is a detailed view of the apertured disk or chopper various
shown),
moving parts. A corresponding chain guide (not
is also used to guide the lower roller timing chain.
disk.
FIG. 2 is a top view of a continuous belt press system 10,
FIG. 8 is a timing diagram of the positions of the upper which shows in greater detail the chain drive system used for
and lower roller chains. the upper press beltsystem 23. Similar or identical apparatus
FIG. 9 is a block diagram of the position indicator system is also associated with the lower press belt system 25.
and its calibration mechanisms. Mechanism 42 drives the chain drive axis 20, which drives
sprockets which mate with roller timing chain 48. Thus, two
FIG. 10 is a block diagram of the electronic control roller timing chains 48 are associated with both the upper
system used to monitor and control roller position. 65 and lower press belt system. The top press belt system 23 is
FIG. 11 is a flow diagram of the control system set forth supported by top belt press supports 44. Belt press open/
in FIG. 9. close cylinders 34 are activated to raise the upper press belt
 5,626.804
5 6
system 23. Press belt 18 is driven by belt drive mechanism and arm lock 85. Sensor arm bolt 104 is fastened to the
50. The roller timing chains 48 (two used for the upper press sensor arm 108 through the sensor arm adjustment slot 106.
belt system 23 and two used for the lower press belt system Adjustment slot 106 permits the sensor arm to be moved to
25) are connected to both ends of a series of rollers 62, and a position where the chopper hub 110 can be interconnected
cause these rollers 62 to move along with and support the to the axis of rotation (axle) 20.
press belts 18 and 19. Chopper disk 160, shown in greater detail in FIG. 6,
FIG. 3 is a diagram of the roller drive system of the lower rotates between a pair of fiber optic sensors 116. Fiber optic
press belt system 25. Each of rollers 62 is fastened at each sensors 116 are used to sense the angular position of the
end to a separate roller timing chain 48 (which follow chopper disk 160. In actuality, one of the sensors 116 is an
pathway 64, and are shown at FIG. 4), where one timing 10 emitter, while the other sensor is the actual sensor that senses
chain 48 is located at each side of upper press 23, and one the position chopper 160. That is, the rotation of chopper
timing chain 48 is located at each side of lower press 25. In 160, with its apertures 142 interposed between sensors 116,
all, four timing chains 48 are used to construct a belt press allows the angular position of the chopper 160 to be deter
10. Chain drive sprockets 20 (shown at FIG. 1) rotate about mined at all times. Sensors 116 are part of a fiber optic
their respective roller chain axes of rotation 20, and drive the 15 system, which is mounted to the fiber optic sensor mounting
roller timing chains 48 along the pathway 64. In turn, the plate 118. Mounting plate 118 is attached to the sensor arm
rollers 62 are driven by the chains 48. The rollers provide 108 by sensor plate bolt 120. Sensor mounting plate bolt 120
support and transfer heat to the press belts 18 and 19. The is mounted through the sensor mounting plate slotted adjust
rollers 62 allow the belts to glide through the pressing region ment 122. Slotted adjustment 122 is used so that the aper
51 (between belts 18 and 19) of the belt press system 10, tures 142 can be aligned with the sensors 116. Because the
even though a high degree of friction can be applied when position of the sensors is so critical, mounting pins 119
press material enters the pressing region 51 via the press gap (shown at FIG. 6) are used to secure the position of the plate
entrance 21. Since platens 31 can be heated, and rollers 62 118 after the sensors 116 have been calibrated with respect
can transfer heat to the press belts 18 and 19, and ultimately to the apertures 142.
to the press material, the rollers 62 ensure that an equal 25 FIG. 6 is a side view of position indicator system 100,
amount of force is applied to the press material throughout shown with chopper disk 160 and its apertures 142. Sensor
the length of the press region 51. mounting plate bolt 120 can be adjusted within adjustment
FIG. 4 is a cross-sectional view 4-4 taken from FG. 3, hole 122. Sensor mounting plate 118 is adjusted to obtain
which shows a platen 31 and roller 62 in greater detail. equal fiber optic light signals. That is, the light impulses of
Platen 31 can be heated or cooled by circulating fluid of 30 the optical fiber should optimally be centered within the
various temperatures through platen viaduct 71. Roller 62 is circular apertures 142, so that the “ON” and "OFF" signal
fastened to two roller timing chains 48, one on each side of durations are equal. This is achieved by moving plate 118
the press belt system 10, by roller connecting pins 86. until sensors 116 and apertures 142 are precisely aligned
Connecting pins 86 are used to fasten each roller 62 to each within the confines of bolt 120 and bolt hole 122. Once the
link in the roller timing chain 48. Each of the links of the 35 precise optimum location of plate 118 is determined, mount
roller timing chain 48 also have bearings 49 associated with ingpins 119 (two pins 119 for the top press 23 and two for
them. Bearings 49 travel, that is, roll through, a mating slot the bottom press 25) are installed to lock in the relative
in the roller timing chain guide 36. Chain guide bolt 84 and position between the sensors 116 and apertures 142. By
mounting bolt 89 are used to fasten the chain guide 36 to the using permanent mounting pins 119, provision is made for
chain guide support bracket 88. As shown in FIG. 4, press 40 the subsequent disassembly of the entire apparatus for
belt 18 is supported by roller 62, which translates heat from servicing and then, returning the press into service without
the platen 31 to the press belt 18, while also facilitating the the need to re-calibrate the sensors 116 with respect to the
movement of the press belt 18 through the pressing region apertures 142, since pins 119 fix plate 118 to arm 108.
51 of the upper belt press system 23, even under high Sensor bolt 104 and slot 106 are used to allow for angular
loading conditions. 45 rotation of plate 118 to adjust the relative timing between the
FIG. 5 is a top view of the roller timing chain position top and bottom press (23 and 25 respectively) chains 48, so
indicator system 100. The roller chain axis of rotation (an that angular synchronization is achieved. In effect, the arm
axle) 20 is connected to an apertured disk 160, also called a 108 can be moved to position the sensors 116 over one of
chopper disk. The apertured disk 160 is fastened to the disk two consecutive apertures 142 (i.e., retard or advance), so
or chopper hub 110, which rotates along with axle 20, by 50 that the aperture 142 being scanned by an upper sensor 116
chopper disk bolts 129, as shown in FIG. 5. Chopper disk is the same as that being scanned by allower sensor 116. Arm
bolts 129 are inserted through sets of holes (either set 125 or lock 85 rotates aboutbolt 84 to cause arm 108 to swing and
set 127, as shown in FIG. 7), and one dowel pin 124 is pivot about the bolt 104, which loosely cooperates with
inserted to permanently calibrate the angular position of the oversized hole 106. That is, bolt 104 does not compress arm
chopper disk 160 with respect to the chopper hub 110. Two 55 108 against arm lock 85; rather, bolt 84 tightly fastens arm
roller pins 86 (and corresponding rollers 62) are inserted into lock 85 to the chain guide 36.
one end of each link of timing chain 48. The opposite end of FIG. 7 is a detailed view of the chopper disk 160, shown
each link of timing chain 48 is disposed across the teeth of with apertures 142. Chopper disk 160 is bolted to chopper
drive sprockets 20. In this manner, chopper 160 rotates in hub 110 by using a total of three mounting bolts 129
sync with the movement of the timing chain 48. One mounted in either hole set 125 or 127. Mounting bolt holes
position indicator system 100 is associated with upper press 125 or 127 are offset by 30, which permits the angular
belt system 23, and a second position indicator system 100 position of chopper disk160 to be coarsely adjusted. Locator
is associated with the lower press belt system 25. holes 124 (shown in FIG. 7, and corresponding dowel pins
The chopper hub 110 and chopper disk 160 together rotate 124 (shown in FIG. 6) are used to set the final desired
synchronously with the chain drive axes of rotation 20. 65 position of the plate 160 with respect to the chopper hub 110.
Sensor arm 108 is connected to the chain guide 36 by sensor In this manner, the plate 160 can be permanently calibrated
armbolt 104, sensor arm mount 107, guide mounting bolt 84 with respect to the overall sensor system.
 5,626,804
7 8
The ability to exactly position the apertures 142 directly It is a principal object of the present invention to provide
over the sensors 116 is critical. Sensors 116 sense the a system whereby rollers 62 are evenly spaced apart such
periodic flows ("ON") and blockages ("OFF") of light that at any given instant in time, only one roller 62-either
through the chopper disk 160. Ideally, a center chord (along a top or bottom roller-will be aligned with the press gap
the diameter) of the light beam emitted from light sensors entrance 21 at a time. In this manner, press product defects
116 travels directly over a center chord of the apertures 142. are prevented. FIG. 9 is a block diagram of the position
If, however, the sensors 116 are misaligned, the centers of indicator system 100 and its calibration mechanisms, shown
sensors 116 will pass over a chord of apertures 142, where with chopper disk 160, certain apertures 142, fiber optic
such chord length is less than the diameter of the apertures electronics 192 and programmable logic controller (“PLC")
142. In this event, the ON/OFF signals transmitted by 10 196. Waveforms 182 and 184 are transmitted along line 194
sensors 116 will be distorted. Specifically, the ON and OFF (that is, waveform 182 for the top position indicator system
durations will not be equal and will be skewed in proportion 100 and waveform 184 for the bottom position indicator
to the difference between the chord length of travel across 100). Fiber optic electronics 192 are connected to sensors
the apertures and the diameter of the apertures. This will lead 116, which sense the apertures 142. Sensor arm 108 is shown
to erratic results. Generally, the diameter of sensors 116 is 15 with its sensor mounting adjustment 122 and its sensor arm
Small in comparison to that of the apertures 142. The hole adjustment 106. Adjustment 122 is used to position the
distance between consecutive apertures 142 on chopper sensor 116 over the apertures 142, while adjustment 106
plate 160 is equal to the diapeter of the apertures. In this
manner, a 50% duty-cycle is output by the sensors 116. That allows sensor arm bolt 104 to be used to coarsely set the
is, as the sensor 116 traverses the apertures 142, the sensors position of the entire position indicator assembly 100 with
ideally traverse the center chord (or diameter) of the aper 20 respect to the belt presses 23 and 25. FIG. 10 is a block
tures 142 (a distance d), and then traverse the a portion of diagram of the electronic control system 200 used to monitor
plate 160 without an aperture, also a distance equal to d. In and control the positions of upper and lower rollers 62. One
turn, the sensors 116 scan all apertured and non-apertured sensor unit 116 is associated with each belt press (23 and
sectors of the plate 160, and output a 50% duty-cycle 25), and a high speed counter unit 202 receives the sensor
waveform. Finally, the number of apertures 142 in plate 160 25 output. The high speed counter 202 outputs its signal
is proportional to the number of teeth in sprockets 20, so that (indicative of the angular position of the chopper disks 160)
Sprockets 20 angular position can at all times be ascertained to the programmable logic controller 196. A digital input/
by sensing the plates 160. output interface 204 to the PLC 196 is used to control
In FIG. 8, a timing diagram 180 of the upper and lower various aspects of the optical fiber sensors 116, and other
position indicator systems 100 is shown. As shown, the 30 digital control circuitry, to ensure that the PLC is pro
duty-cycles of both the upper (182) and lower (184) sensor grammed in a manner to achieve the functionality of the
116 outputs is at 50%, which is ideal. If, however, the present invention. Analog inputs 206 are supplied from the
diameters of the sensors 116 and apertures 142 do not press belt system 10, which are merely indicators of the
precisely align, other duty-cycles will result, and the posi speed of the upper and lower belts 18 and 19. The signals
tions of the chopper disks 160 cannot be accurately read. 35 received from the belt press 10 indicative of press speed can
Distortion is created. As shown in FIG. 8, the rising edges be supplied, for example, by a simple low voltage generator
of the top chain waveform 182 correspond to the middle of connected to axle 20. Analog outputs 208 are bias signals
the OFF period (or lower level) for the lower chain wave used to control (or alter) the speeds of the belts 18 and 19.
form 184. That is, a 90° phase shiftis present, indicating that For most applications, it is only necessary that the speed of
the upper and lower chopper plates are alternating. In 40 one belt be controlled, since it is the relative position
sequence: at 183, the lower chopper has just closed; at 185, between the upper and lower presses that is critical. In this
the upper chopper has just opened; at 186, the lower chopper manner, for example, the speed of belt 19 can be adjusted,
has just opened; at 187, the upper chopper has just closed; while the speed of the upper belt 18 is maintained. Because
at 188, the lower chopper has just closed. This sequence of the PLC 196 transmits a bias signal 208 to one chain drive
events is repeated continuously, and as shown by diagram 45 mechanism 42 or the other, and because the PLC receives
180, the positions of upper and lower chopper plates 160 are belt speed feedback along input 206, PLC 196 is capable of
precisely staggered. This condition is ideal, because it is adjusting the speeds of the chain drives (and in turn, the
indicative of the fact that the upper and lower roller chains roller timing chains 48) so that the rollers 62 are always
48 and their sprockets 20 are also staggered, or out of phase. staggered as taught by the present invention. Counter 202
In turn, the positions of the upper and lower rollers 62 are 50 continuously supplies PLC 196 with a signal indicative of
also necessarily staggered. This is a principal object of the the roller 62 positions, so PLC 196 can react by changing the
present invention-to keep the upper and lower rollers 62 speeds of the roller chains 48 via output 208. PLC 196
from ever overlapping, particularly at the press gap entrance adjusts the roller chain 48 speed until an appropriate degree
21, where press material defects or damage can result. offeedbackis received along input 206. Then, the PLC will
Specifically, waveforms 182 and 184 must never be allowed 55 only react further if counter 202 is indicating that an overlap
to overlap. If they do, such would indicate that the upper and condition is approaching. Thus, PLC 196 can control the
lower rollers 62 have aligned, one on top of the other. If that positions of the upper and lower rollers 62.
occurred, then the press belts 18 and 19 would both have FIG. 11 is a flow diagram of the control system 200,
rigid support members (rollers 62) behind them at identical including an initial set-up step 222. Initial setup step 222
points at the press gap entrance 21. When press products must be performed before the system is activated. The
such as laminates are being fabricated by the continuous belt adjustments along sensor arm 108 are provided for that
press 10, defects can result if the products are "pinched” at purpose. Adjustment 106 is adjusted so that the chopper hub
the press gap opening 21. Such "pinching” occurs when 110 is aligned with the axis of rotation 20. First, sensor bolt
rollers 62 are collocated behind their respective press belts 120 within hole 122 is adjusted so that sensors 116 are
18 and 19. When this occurs, a localized high loading upon 65 aligned with the apertures 142. Sensor 116, which has a
the belts 18 and 19 are impinged against the press product, diameter substantially less than that of the apertures 142 of
and so called bar marks or other defects can result. plate 160, is aligned to pass directly over the centers of
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10
apertures 142. By moving bracket 118 (at FIG. 6), alignment sensing means disposed about said apertured disk for
of sensors 116 is accomplished so that a 50% duty-cycle is sensing the angular position of apertures of said aper
achieved. When a 50% duty-cycle is achieved, bracket 118 tured disk; and
is locked into position with pins 119. This is performed only controlling means attached to said motor for adjusting the
once for the initial calibration step. Then, sensor arms 108 speed of said motor in response to said sensing means.
(both on the top and bottompresses (23 and 25 respectively), 2. A controller according to claim 1 wherein said sensing
can be adjusted so that the upper and lower sensors 116 and means is an optical sensor having emitter and sensor means.
their respective sets of apertures 142 are in phase. That is,
when an aperture 142 is passing between an upper sensor 3. A controller according to claim 1 wherein said control
116, so is a lower aperture passing between its correspond 10
ling means is a programmable computer.
ing sensor. Then, the apertures 142 are synchronized with 4. A controller according to claim 1 wherein said control
the rollers 62. By adjusting the upper and lower sensor arms ling means is a programmable logic controller.
108 (by bolts 104 disposed within holes 106), and locking 5. A method for controlling the position of rollers asso
them into place by arm locks 85, the upper and lower sensor ciated with a belt forming a part of a continuous belt press,
systems are calibrated with each other, so that the relative 15 said method comprising the steps of:
positions between the upper and lower rollers 62 can be mounting an apertured disk upon a belt press rotating axle
controlled, optimally, so that they are exactly staggered,
alternating (between top and bottom) on their approach to wherein said rotating axle rotates synchronously with a
the press gap entrance 21. roller chain of said belt press, and wherein apertures
The chopper 160 may need to be skewed by selecting the upon said apertured disk correspond to the position of
20 said rollers fixed to said roller chain;
alternate set of holes between sets 125 and 127. The chopper sensing the angular position of apertures upon said aper
160, which is used to "chop” the light used by sensor 116, tured disk; and
is then permanently calibrated or keyed by dowel pins 124.
In this manner, coarse and fine adjustments are provided so adjusting the speed of said roller chain in response to the
that the position indicator system 100 can be calibrated. 25 position of said rollers, wherein the position of said
rollers is determined by sensing the angular position of
Next, the upper press 23 and lower press 25 are set into said apertures.
motion at step 224 and the waveforms 182 and 184 are 6. A method for controlling the position of rollers asso
checked for a 50% duty-cycle. The presses 23 and 25 are ciated with the continuous belt press according to claim 5,
permitted to run freely during this step, without any loading. 30 further comprising the step of:
If the duty-cycles are not at 50%, then the slotted adjust calibrating the position of a sensor for sensing the pres
ments must be made again, until both waveforms 182 and ence of apertures upon said apertured disk so that said
184 are at 50% (50% ON and 50% OFF). The rollers 62 may sensor produces either an “ON” or "OFF" signal cor
also be moved manually (step 228) before the press 10 is responding to whether one of said rollers is positioned
closed (step 234). When the presses are first closed (step 35 at an entrance of said continuous belt press.
236), an initial bias signal 230 will be applied. If the press 7. A method for controlling the position of rollers asso
10 has not been just closed, the relative positions of the top ciated with the continuous belt press according to claim 5,
and bottom rollers will be checked at step 238. If the speed further comprising the step of:
is OK (232), no bias signal will be applied. However, if the calibrating the position of said apertured disk with respect
waveforms 182 and 184 do not overlap as shown in FIG. 8,
40 to said belt press rotating axle so that a sensor for
sensing the position of said apertured disk produces
then a lead 246 or lag 244 situation will be detected, and the either an “ON” or "OFF" signal corresponding to
bias will be either reduced 250 or increased 248, which whether one of said rollers is positioned at an entrance
results in the appropriate stimulus output at 208. This insures of said continuous belt press.
that the upper and lower rollers 62 are exactly staggered as 45 8. A roller position controller for use with a continuous
they reach the press gap entrance 21. This flow is then belt press having a plurality of rollers disposed across each
repeated back to “A” (226). The bias signals (determined at of two belts, wherein said two belts are aligned in close
248 and 250) will both increase or decrease the speed of, for proximity one above the other to form a press gap entrance
example, the bottom belt 19 and its rollers 62. In this through which material to be pressed is inserted, compris
manner, the speed of the bottom rollers 62 can be adjusted
50 ing:
so that the perfectly alternating or staggered roller pattern an upper platen;
(represented by FIG. 8) can be sustained. an upper press belt, with upper rollers driven by an upper
It is further contemplated that after having read the roller chain wherein said upper rollers are disposed
between said upper platen and said upper press belt;
preceding disclosure, other alterations and modifications of 55
a lower platen;
the present invention will become apparent to those skilled a lower press belt, with lower rollers driven by a lower
in the art. It is intended that the following claims be roller chain wherein said lower rollers are disposed
interpreted to cover all such obvious alterations and modi between said lower platen and said lower press belt;
fications. an upper apertured diskmounted to an upper rotating axle
We claim: wherein said upper axis and said upper apertured disk
1. A roller position controller for use in a continuous belt rotate synchronously with the movement of said upper
press having a plurality of rollers mounted upon a chain roller chain and where the apertures of said upper
driven by a sprocket turned by a motor, said controller apertured disk are indicative of the positions of said
comprising: 65 upper rollers with respect to said press gap entrance;
an apertured disk mounted upon and synchronously a lower apertured disk mounted to a lower rotating axle
rotated with said sprocket; wherein said lower axis and said lower apertured disk
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11 12
rotate synchronously with the movement of said lower optical sensor having emitter means and means sensitive to
roller chain and where the apertures of said lower said emitter means.
apertured disk are indicative of the positions of said 11. A roller position controller according to claim 10
lower rollers with respect to said press gap entrance; wherein said optical sensor is positioned to sense a beam of
upper and lower sensor means, wherein said upper sensor light passing through said apertured disk.
senses the angular position of apertures of said upper 12. A roller position controller according to claim 8
apertured disk and wherein said lower sensor senses the wherein the position of said upper or lower sensor means is
angular position of the apertures of said lower aper adjustable with respect to the position of said apertured disk.
tured disk; 13. A roller position controller according to claim 8
10
comparison means for comparing the angular positions of wherein said apertured disk is rotatably fixable and is
said upper and lower apertured disks in response to said adjustable with respect to its associated axis of rotation.
upper and lower sensor means; and 14. A roller position controller according to claim 8
control means coupled to said comparison means for wherein said control means causes said upper and lower
controlling the relative position between said upper 15 rollers to reach said press gap entrance at distinct times.
rollers and said lower rollers. 15. A roller position controller according to claim 8
9. A roller position controller according to claim 8 wherein said upper or lower sensor means includes an
wherein said comparison means is computer. electronic photo-sensitive device.
10. A roller position controller according to claim 8
wherein said upper or lower sensor means consists of an :: * : :: ::