U.S. patent number 3,851,685 [Application Number 05/308,556] was granted by the patent office on 1974-12-03 for continuous press.
This patent grant is currently assigned to Eduard Kusters Maschinenfabrik. Invention is credited to Karl-Heinz Ahrweiler, Valentin Appenzeller, Eduard Kusters, Kurt Quoos.
United States Patent |
3,851,685 |
Ahrweiler , et al. |
December 3, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
CONTINUOUS PRESS
Abstract
A continuous press has two rotatively driven endless conveyor
belts forming opposed, substantially linear spans defining a
pressing zone, press platens applying pressure through these
traveling spans to work carried therebetween, and anti-friction
means being interposed between the platens and the spans. Such a
press is improved in that the anti-friction means is formed by a
multiplicity of endless loops of rotatively unpowered roller chains
forming a bed interposed between the platens and the belt spans,
the roller chain spans extending longitudinally with respect to the
belt spans and being transversely packed together, but each chain
being individually free to travel independently with respect to the
others and to the belt span.
Inventors: |
Ahrweiler; Karl-Heinz (Krefeld,
DT), Appenzeller; Valentin (Kempen/Ndrh,
DT), Quoos; Kurt (Krefeld, DT), Kusters;
Eduard (Krefeld-Forstwald, DT) |
Assignee: |
Eduard Kusters Maschinenfabrik
(Krefeld, DT)
|
Family
ID: |
25762056 |
Appl.
No.: |
05/308,556 |
Filed: |
November 21, 1972 |
Foreign Application Priority Data
|
|
|
|
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Nov 22, 1971 [DT] |
|
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2157746 |
Oct 5, 1971 [DT] |
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2248760 |
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Current U.S.
Class: |
100/154; 100/151;
425/371; 156/583.5; 425/394; 100/311 |
Current CPC
Class: |
B30B
5/067 (20130101); B29C 43/48 (20130101); B29C
43/22 (20130101); B30B 5/06 (20130101); B27M
3/04 (20130101); B29L 2031/3041 (20130101); B29C
2043/483 (20130101); B29K 2105/06 (20130101); B29K
2105/0809 (20130101) |
Current International
Class: |
B29C
43/22 (20060101); B30B 5/00 (20060101); B29C
43/48 (20060101); B29C 43/44 (20060101); B30B
5/06 (20060101); B27M 3/04 (20060101); B27d
003/04 () |
Field of
Search: |
;425/224,364,371,394,383,406 ;100/151,152,153,154,93RP ;156/583
;144/281R,281A,281B,281C,281D,281E,283 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Bray; W. D.
Attorney, Agent or Firm: Kenyon & Kenyon Reilly Carr
& Chapin
Claims
What is claimed is:
1. An improved continuous press including endless loops formed by
longitudinally and transversely flexible conveyor belts which form
opposed, substantially linear spans defining a pressing zone, means
for rotatively driving at least one of said loops to drive said
spans in the same direction, press platens applying pressure
through said traveling spans to work carried therebetween, and
anti-friction means interposed between said platens and said spans;
wherein the improvement comprises said anti-friction means being
formed by a multiplicity of endless loops of rotatively unpowered
roller chains forming a bed interposed between said platens and
said belt spans, said roller chain spans being transversely packed
together but each chain being individually free to travel
independently with respect to the others and said belt spans.
2. The press of claim 1 in which stationary metal strips are
interposed between said roller chains to separate them from each
other.
3. The press of claim 1 in which the rollers of said roller chains
are in sets of two or more axially aligned rollers rotatively
mounted on a common pin and linking plates located between the
rollers of said sets interconnect the sets, the transverse width of
the sets being less than can span localized deformations of said
conveyor belts.
4. The press of claim 1 in which said platens have flat plane
surfaces on which the rollers of said roller chains roll.
5. The press of claim 1 in which said roller chains when free from
said pressing zone are looped at differing levels around one of the
platens and a plate has passages at corresponding different levels
through which the chains travel and which is positioned against
said one of the platens to transmit pressing force
therethrough.
6. The press of claim 1 in which said roller chains have
transversely offset rollers of different lengths providing
overlapping rolling paths.
7. The press of claim 3 in which the rollers of said sets are of
differing lengths providing overlapping rolling paths.
8. The press of claim 3 in which stationary metal strips are
interposed between said roller chains to separate them from each
other.
9. The press of claim 5 in which said passages are transversely and
vertically offset with plate material diagonally therebetween and
said passageways are dimensioned vertically to provide clearance
for the roller of said roller chains preventing them from receiving
the pressing force.
10. The press of claim 9 in which said passages are channels, said
plate being engaged on one side by the platen and pressing beams
applying pressure on the plate's other side.
Description
BACKGROUND OF THE INVENTION
This invention relates to continuous presses of the type including
endless loops formed by longitudinally and transversely flexible
conveyor belts which form opposed, substantially linear spans
defining a pressing zone. Means are provided for rotatively driving
one or both of the loops to drive the spans in the same direction,
and press platens apply pressure through the traveling spans to the
work carried therebetween. Antifriction means are interposed
between the platens and the spans for obvious reasons. Such presses
are used for the manufacture of wood-chip board, laminated
products, minerally-bonded construction boards or plates, for
sintering sheets of polytetrafluorethylene, etc.
When, to manufacture wood-chip board for example, such a press is
used for the consolidation of the wood-chips, the flexible belt
spans through which the pressing pressure is transmitted, may
locally flex and stretch unpredictably, and the above-mentioned
anti-friction means should be capable of operating satisfactorily
under such random stressing conditions. Similar conditions are not
encountered by either roller or ball bearings in general, because
rigid bearing races apply the load uniformly throughout the rolling
elements.
DESCRIPTION OF THE PRIOR ART
However, more recent prior art suggestions in the direction of
providing anti-friction means for continuous presses have, in
general, attempted to borrow from the anti-friction roller and ball
bearing art.
For example, at an earlier time the Beard U.S. Pat. No. 2,142,932,
Jan. 3, 1939, suggested the use of rollers extending for the full
width of the belt spans defining the pressing zone. The ends of
these rollers are linked together to form roller loops having spans
between the conveyor belt spans and the press platens, at least one
of the latter being formed by a fluid-filled cushion so that the
rollers vertically receive uniform pressure lengthwise. But in a
horizontal plane, these full-length rollers receive the random
stressing and must constantly flex while rotating, an operating
condition known to lead to early fatigue failure of metal. Also,
such stressing produced skewing forces which must be restrained by
the journals in which the rollers necessarily run in the links
which interconnect them. Beard does not suggest that this
construction is suitable for the manufacture of chip-board.
Therefore, borrowing from the anti-friction bearing art to relieve
the rolling elements from such flexure and skewing, the Burger Pat.
U.S. No. 3,120,862, Feb. 11, 1964, suggests the elimination of the
flexible conveyor belt and its substitution by a chain made of long
and strong links interconnected to permit looping and the formation
of the two conveyor spans between the press platens. The patent
suggests that with this construction either roller or ball bearing
elements may be used between these links and the press platens.
Both the links and the press platens are grooved to form rigid
bearing races holding the rollers or balls in alignment, which
involves expensive precision machining operations. The rolling
elements may be caged to form endless loops or run as loose
elements. The links required for cooperation with the press platens
to form the typical bearing, races, although linear instead of
circular, involve large engineering and manufacturing costs.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a continuous
press of the type described, which is improved in that its
anti-friction elements are substantially free from flexure and
skewing stresses, and which can be made at a manufacturing cost
that is commercially acceptable.
According to the present invention, the flexible conveyor belts are
used, in particular, belts made of strip steel having a gauge in
the area of 1 mm. thickness. This has the advantage of low cost,
imperviousness and effective heat and pressure transmission
properties.
Between these belt spans forming the pressing zone, and the press
platens, a multiplicity of rotatively unpowered endless loops of
roller chains are used, these being packed transversely together to
form a bed interposed between the platens and the steel strip
conveyor belts. The chains are not only unpowered, but also each
chain is individually free to travel independently with respect to
the others as well as the belt spans themselves. For a belt width
in the area of 2 or 2.5 meters, more than 100 of these chains may
run side-by-side, each individually free to adopt any traveling
velocity independently of all of the others. Each chain is free to
change in velocity with respect to the steel belts. The individual
rollers are, for all practical purposes, entirely free from
horizontal flexure and skewing stresses caused by belt flexure or
stretching because each roller is so very short in length
individually and does not span the belt areas under deformation.
Skewing forces are translated into individual accelerating and
decelerating velocities of the various chains. Flexure stresses
only result in the chains moving relative to each other.
The two outermost chains of each roller chain bed are guided
against transverse displacement, thus holding all of the chains
packed therebetween from displacement. There is no need for
expensive precision machining operations to form bearing races in
the platens.
Standard, light-weight machinery roller chains may be used. A
successful experimental machine embodying the above features
located in Germany uses a chain roller diameter of 12.77 mm. This
would generally correspond to American Standard ASA light weight
machinery chain, designated as No. 41, having a nominal roller
diameter of 0.306 inch, or possibly No. 40 having a 5/16 inch
roller diameter. The roller width of No. 41 is 1/4 inch, and of No.
40, it is 5/16 of an inch. In other words, with this present
invention, as a generality, the roller length should not be very
much greater than the roller diameter although this relationship
may be exceeded to meet special circumstances providing the roller
length is not so great as to span the localized belt deformation to
be expected.
When standard roller chains are used, the roller pins should not
protrude beyond the pin-link plates to a degree causing chain
interlocking preventing the individual free travel of adjacent
chains. Obviously the rollers should have a diameter greater than
their interconnecting plates; if a nonstandard construction is
used, it should be kept in mind that the rollers must be linked
together so the rollers can perform their anti-friction function.
In any event, chain interference can be prevented in the case of
the present invention by the use of thin strips of steel, such as 1
mm. thick, extending between the chains in vertical planes and with
their ends anchored at the entering end of the pressing zone.
The transverse spacing between the rollers of the packed roller
chains of standard construction is only that of the roller's
interconnecting plates, which is normally small. To meet special
conditions, the roller link plates may be modified either by making
them with transversely offset portions or by modifying their normal
overlapping relationship, permitting the use of rollers of
differing lengths having overlapping travel paths. Although such
arrangements use longer rollers, their individual lengths should be
kept within the limits previously described.
DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are illustrated by
the accompanying drawings in which:
FIG. 1 is a side elevation of a continuous press embodying the
invention;
FIG. 2 is a longitudinal vertical section of that press shown very
schematically;
FIG. 3 is a cross section of the press;
FIG. 4 is a vertical cross section showing only a small portion of
an upper press platen with the roller chains transmitting its force
to the steel strip conveyor belts;
FIG. 5 is the same as FIG. 4 but shows the modification of divider
steel strips separating adjacent chains;
FIG. 6 is a vertical longitudinal section of the entering end
portion of an upper platen, showing the ends of the chain
loops;
FIG. 7 and 8 are like FIGS. 5 and 6, respectively, but show
modifications;
FIG. 9 entirely schematically suggests the transversely offset
chain plates with the rollers of differing lengths to provide
overlapping roller paths;
FIGS. 10 and 11, each partly sectioned, suggest how the rollers may
be interfastened by differently overlapped link plates to permit
the use of rollers of differing lengths to provide overlapping
rolling paths.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the upper and lower endless conveyor belt loops 1 and
2 respectively, which form opposed, substantially linear spans
defining the pressing zone embraced by the bracket 3. These belts
are made of thin strip steel having a thickness of about 1 to 1.5
mm. and are flexible both longitudinally and transversely. The
upper belt 1 is looped around rotative drums 4 and 5, the drum 4
being fixed against lateral motion by being journaled in stationary
pedestals 6; the drum 5 being capable of lateral motion by being
journaled in swinging arms 7 provided with suitable swinging means
8 which provide for the application of proper tension to this upper
belt. The lower belt 2 at one end loops around a rotative drum 9
which is also fixed against lateral motion by being journaled in
stationary pedestals 10, the other end of this lower loop passing
around a rotative drum 11 journaled in sliding mountings 12 pulled
by suitable actuating means 13 so that the tension of the lower
belt loops may be properly attained.
The work W enters at the right-hand end of the press, in FIG. 1,
and comes out the left-hand end with a reduced thickness, assuming
wood-chip board or the like is being made.
As shown by FIG. 3 the working spans of the two belts in the zone 3
are pressed together by press platens 14 and 15, the lower platen
14 being held against downward motion by transverse I-beams 16
supported by base members 17 which extend longitudinally for the
length of the press. The upper platen 15 is supported by transverse
I-beams 18 which can be pulled downwardly by suitable actuators 19
which may be either of the motorized mechanical screw t7pe or
hydraulically actuated. There are a plurality, or series, of these
beams 16 and 18 and each of the upper beams 18 is provided with its
own pair of actuators 19.
The platens 14 and 15 each extend for the full length of the zone 3
as one-piece constructions, excepting that, as suggested in FIG. 2,
the upper one may be in two sections to define a converging
entrance zone for the work so that the latter can receive a
gradually increasing pressure as it initially enters the press.
Although the beams 16 and 18 are shown as being relatively massive
and, therefore, very resistant to beam stress, it is still possible
for them to deflect slightly under the loading applied by the
actuators 19. Should this deflection be troublesome, hollow
cushions may be used between the beams and the platens, these
cushions extending for the full length of the beams with which they
are used and being made of flexible sheet metal, for example, and
filled with fluid under pressure sufficient to carry the loading to
which the beams are subjected. With such an arrangement beam
deflection is not transmitted to the platens. In schematic FIG. 2
such cushions are indicated at 21. They may be used between any of
the beams or all of the beams whenever needed to obtain a uniform
loading throughout the widths of the platens.
The roller chain loops providing the anti-friction means between
these platens and the steel strip conveyor belt spans throughout
the pressing zone 3, are generally indicated in FIG. 2, the roller
chains 22 extending between the lower belt 2 and the lower platen
14 and being individually looped by individual looping sprocket
wheels 23 appropriately positioned and which are unpowered and
rotatively free from one another. It can be seen that these roller
chain loops 22 encircle both the lower platen 14 and its supporting
beams 16. By lengthening the upper belt loop 1, the same
arrangement could be used for the upper roller chain loops 24 which
must run between the upper belt loop and the upper platen 18; but
by specially designing the upper platen, as disclosed hereinafter,
the chain loops 24 may be much more compactly arranged as is very
generally indicated by FIG. 2.
Having reference now to FIGS. 4 through 6, the chain loops are
shown as they appear with their spans running between the upper
platen 18 and the upper flexible belt loop 1. The above-mentioned
special roller chain loop arrangement is not used in this instance,
the chains entering the spanning length via semi-circular guiding
surfaces 25 keyed to the ends of the platen 15 and looping in the
manner of the lower chain loops. Inverting these FIGS. 4 through 6
provides a fairly clear representation of the lower platen and its
anti-friction means.
As shown by FIGS. 4 and 6, each chain comprises inside link plates
26 between which steel rollers 27 are journaled on pins 28 passed
through these plates, and outside link plates 29 through which the
pins 28 also pass to form the chain. The outside plates have
countersunk holes in which the ends of the pins are flared to
provide the outside plates with smooth-flat plane surfaces beyond
which the pin ends do not project. The rollers 27 are 12.77 mm. in
diameter, as previously mentioned, so it can be seen that FIGS. 4
through 6 are substantially full scale or 1:1 drawings. It can also
be seen that the rollers are not substantially longer than their
diameters. With the platen width being in the area of from 2 to 2.5
meters, and with each of the roller chains 27 having widths not
much greater than the 12.77 roller diameter, plus the thickness of
the relatively thin plates 26 and 29, there must be a very great
number of the roller chains 24 which form the anti-friction bed
interposed between the traveling steel strips and the platens.
Neither the lower rolling chain loop guiding elements 23 in FIG. 2
nor the elements 25 illustrated by FIG. 6, either drive or
rotatively interlock the chains. Each chain is entirely
individually free to travel at any velocity it may acquire
independently with respect to the others and, of course, with
respect to the steel strip belt spans. The chains are held
transversely packed together and substantially intercontacting by
end guides 30 fixed to the platens; because the chains outside
plates 29 are smooth the chains can slide relative to each other
when necessary. The rollers 27 are all individually very short as
previously noted. Because the chains are capable of random movement
relative to each other, their various rollers are substantially
incapable of becoming transversely aligned to any great extent. As
the steel strip belts locally deform or stretch, the velocities of
the various chains in the affected areas can change individually so
that no roller horizontal flexing, twisting or other strain can be
involved, only the press force being carried. Localized belt
stretching is due to the thinness of the steel strip belts which is
in the area of from 1 to 1.5 mm. in thickness, and the driving
tension on the belts.
As shown by all of FIGS. 4 through 6, the pressing surfaces 31 of
the illustrated platens are flat plane surfaces free from any
necessity for precision machined channels or rolling element races.
The platen faces may be finished by inexpensive machining, and
although preferably finished as smoothly as possible for obvious
reasons, slight imperfections are relatively immaterial.
Note that the chain plates 26 and 29 do not carry any great
tension, because the chains are undriven excepting by the rolling
action the rollers receive from the traveling metal strip conveyor
belts.
FIGS. 5 and 6 show the thin metal strips 32, which may be steel of
about 1 mm. in thickness, which serve to separate the great
multiplicity of roller chains without substantially increasing
their transverse separating distances. This permits the use of
roller chain pins 28' having ends projecting slightly beyond the
outer surfaces of the outside plates 29. The edges of these strips
32 must be kept from being rubbed by the traveling steel strip
belts and this can be done by letting their opposite ends project
far enough beyond the platens for engagement by tensioning
elements. One such tensioning element is schematically shown at 33
in FIG. 6. Incidentally, in the case of the lower roller chains 22
only the ends of these strips at the entrance end of the machine
need be anchored because the motion of the chains keep the strips
extended while gravity keeps them from engagement with the conveyor
belts.
FIGS. 4 through 6 illustrate the platens as having transversely
extending steam or hot liquid passages 34 which extend completely
through the plates but have their ends interconnected by manifolds
35 which extend lengthwise on opposite sides of the press to
provide for inlet and outlet flows. Thus, the platens are heated,
the passages 34 being spaced far enough apart from each other to
provide intervening areas of solid platen metal through which the
pressing pressure from the transverse beams can travel safely.
Thermal insulation 36 is used where appropriate, such as between
the platens and the manifolds 35 and between the platens and the
beams. These features apply to the lower platen assemblies as
well.
It was previously mentioned that in FIG. 2 a special loop return
arrangement is used for the upper roller chains 24. This is
illustrated by FIGS. 7 and 8. In this figure, the roller chains 24a
are of a different construction than described before. Here each
chain is a double width chain made from pairs of rollers 27a with
the rollers in axial alignment as to each pair and journaled on
common pins 28a and interconnected by links 26a, the flared or
headed ends of the pins being in countersunk holes in the rollers
so that the outer ends of the rollers of each pair are flat and
smooth. The separating strips 32 previously described are used to
separate the various chains and the chains are kept transversely
packed together by end guides 30 as previously described. To
illustrate a possibility, one of these strips shown at 32a is made
high, or wide, enough to extend into a saw kerf 32b cut in the
underside of the upper platen 15 which differs from the ones
previously described principally only in that a sheet metal
manifold 35a is shown instead of the much heavier one 35
illustrated before. With the strip 32a press fitted in the saw kerf
32b it is held upwardly so that only an immovable anchor 33a at the
entrance end of the machine is needed even though in this instance
the upper platen is involved. If the saw kerf 32b is widened in
width, wedges may be used to hold the strip 32a in the saw kerf,
thus eliminating any need for precision work. The sawing of such
saw kerfs is a very simple operation as compared to the precision
machining required to form bearing races.
The fundamental difference between FIGS. 7 and 8 and the
constructions of the preceding FIGS., is that the semicircular
guiding surface shown at 25 in FIG. 6 is made with alternately
differing levels 25a and 25b, these levels being formed by grooves
which start out at the same level and which as the rollers of the
chains leave the steel strip belt 1, gradually diverge upwardly so
that alternating roller chains arrive at or leave at different
levels above the platen 15. Between the platen 15 and the upper
beam 18 a metal plate 37 is interposed to handle these chain spans
traveling at differing vertical heights. This plate 37 has
longitudinally extending passageways 38 and 39 which are laterally
offset transversely and vertically from one another at the
alternately different levels required by the vertically separated
upper chain spans Therefore, the plate 37 can be and is made thick
enough to provide adequate metal diagonally between the passageways
38 and 39 to safely carry the force exerted by the beams 18 and
applied to the platen 15 through this plate 37, and the passageways
38 and 39 can be and are made to have greater heights then the
diameters of the rollers of the chain spans so that these rollers
do not have to carry the press force but can simply run loosely
through their respective passageways. The width of the passageways
38 and 39 should provide just about enough clearance to permit the
chain roller to roll along freely in the passageways. The heat from
the heated platen 15 is conducted into this plate 37 for absorption
by the rollers of the roller chains traveling through this plate's
passageways, thus providing for greater heating efficiency.
Because of the possibility of dust and other contamination floating
around this or any other continuous press, particularly when making
wood-chip board, the space around the roller chains is protected
from the outer atmosphere by shielding 38 provided with a flexible
seal 38a where the strip belts enter or leave the press, and
corresponding side edge seals 38b bearing on these belts. Thus the
roller chains are fully enclosed and by providing the shielding 38
with a source of air under super-atmospheric pressure, the source
being generally indicated at 39, contamination is prevented from
entering the space enclosed around the roller chains. The seals 38a
and 38b need not be air-tight, providing the source 39 introduces
an adequate volume of air to the shielding 38 to maintain a
super-atmospheric pressure surrounding the roller chains.
The above described construction where the idle spans of the roller
chains are vertically separated, is preferably used only for the
upper platen and the upper roller chain loops because, as indicated
by FIG. 2, the lower roller chain loops can be easily arranged to
have clearance, permitting the use of chain guide constructions
such as shown by FIG. 6.
Reference has been made to the roller chains being packed
transversely together. This is intended to mean that the various
roller chains are arranged as physically close together in a
transverse direction as is possible, considering the endwise roller
spacing required by the chain links and the separating or divider
strips 32 and 32a if they are used. Such interspacing is adequately
small for most purposes, but in the manufacture of certain
products, such as for the sintering of sheets of
polytetrafluorethylene, the existence of longitudinally running
impressions may be possible, considering the fact that the conveyor
belts are flexible.
The chance of the above described difficulty to occur is removed by
the roller chain construction shown by FIGS. 9 through 11 because
the chains have sets of axially aligned rollers of different
lengths, with longer rollers of one set opposite shorter rollers of
the next set so that they effect transversely offset rolling paths
free from transverse interspacing.
In FIG. 9 this is done by using special chains, each having pairs
of rollers 40 and 41 journaled on common pins 42 as to each pair,
the pins being interconnected by link plates 43 located between the
rollers of each pair. These link plates differ from those shown in
FIGS. 7 and 8 by having their portions which journal the pins 42
transversely offset as to mutually adjacent roller pairs and these
offset portions interconnected by a transverse portion located
between the roller pairs. The rollers 40 are longer than the
rollers 41 and their relationship is reversed alternately from pair
to pair of the rollers so that spaces between the rolling paths of
any pair of rollers are always immediately rolled over by one of
the longer rollers 40.
With the roller ends made as flush or flat plane surfaces as
previously described, these roller chains of FIG. 9 may be
transversely packed together with their respective roller ends
interengaging without any substantial danger of the chains
interlocking with each other to destroy their individual ability to
accelerate and decelerate relative to each other.
A further form of such chain construction is shown in FIG. 10 in
the form of the chain having strands of straight links 44. These
links in the upper strand however are not aligned in one lane
parallel to the direction of advance but are offset, following one
another, toward the same side. Thus for example the link 44a in
FIG. 10 is offset upward relatively to the link 44. The link 44b is
again offset upward relatively to the link 44a. The link 44c
however is offset downward relatively to the link 44b, and is
followed by four additional links each offset downward, as far as
link 44d, after which an upward offsetting toward the right occurs.
The complete strand of links thus runs in a zig-zag inside the
chain 80, so that the gap left between any two rollers is rolled
over by the following rollers.
The other or lower strand of links 82, has links offset in the
opposite direction relatively to the central plane of the chain.
Each element of the chain therefore consists of three rollers which
change periodically in width, or length, and which taken all
together make a single roller chain with parallel smooth surfaced
delimiting faces.
In FIG. 11 the links 45 are always offset in the same direction so
that the link alignment runs diagonally through the chain with the
lengths of the various rollers being proportioned as required by
such displacement. As the diagonal orientation of the links must
cause a link series to eventually end, it is necessary when this
occurs to reverse the order in which the rollers decrease in length
to start a new series. Thus in FIG. 11 there are two very short
rollers 47 with two longer rollers 48 between them so that at this
point it might be said that a quadruple width roller chain
construction is involved. However, this next changes to a three
roller width where a long roller 49 and two shorter rollers 47a
start the three roller series. This progresses from the left-hand
end to the right-hand end where the diagonally extending series
roller links again phases out, with the rollers 47 and 48 again
appearing as a four roller alignment. It can be seen that this
construction also provides transversely overlapping rolling
paths.
It is to be understood that the chains shown by FIGS. 9 through 11
will be transversely packed closely together as shown in FIG. 7 and
that if the vertical separating strips are used between adjacent
strands, these strips are of such great thinness as not to
interfere substantially with the transversely uniform rolling
action desired.
In all of the constructions shown by FIGS. 9 through 11 the
transverse widths of the roller chains are substantially greater
than in the case of the chains previously described and as they are
shown by FIGS. 4, 5 and 6. The axially aligned rollers do require
common roller linking pins as indicated at 50 in FIGS. 10 and 11,
these incidentally showing how the pin ends can be flush or beneath
the axial ends of the outermost ones of the rollers in all cases.
However, FIGS. 9 to 11 are approximately full scale representations
and it can be seen that the chains' widths are very small as
compared to the overall widths of the conveyor belts and their
pressing platens, the latter of which may well be in the area of
one to several meters in extent. If the widths of the individual
chains were to be increased so extensively that only a few of the
chains would be required transversely, the principles of the
present invention would not be involved.
In conclusion, it can be seen that a fundamental concept of the
present invention is the provision of unpowered roller chains each
free to increase or decrease in velocity independently of the
others and with the widths of the individual chains, or the lengths
of their rollers, extremely small as compared to the overall
transverse width of the platen and of the transversely and
longitudinally flexible conveyor belts, so that a very great number
of transversely packed chains are required to transversely fill the
widths of these two elements of which one must move relative to the
other under pressure. Transversely localized and longitudinal
stretching or other deformation of the flexible conveyor belts can
only result in acceleration or deceleration of the individual
roller chains, the rollers of which are too short individually to
span such localized disturbances. Therefore, the rollers receive
neither horizontal flexure not skewing strains to any extent
capable of affecting their intended operation.
* * * * *