Note: Descriptions are shown in the official language in which they were submitted.
This application :i5 a division ot` application 2~3,840J filed
January 20, 1976.
The present invention relates to an aM aratus for continuously
stretching dough material into a thin web.
One of the inventors of the present invention invented in the past
a device as disclosed in Canadian Patent Application No. 217,37~, wherein a
strip of dough material is fed into and flattened in a path formed be~ween a
group of rollers progressing along an endless path and a plurality o moving
conveyor belts positioned underneath a lower straigh~ portion of said endless
path. Rotating brushes may also be provided between said conveyor belts. In
the above device~ the speed of each of said conveyor belts is faster than that
of the nearest upstream conveyor. The rollers progress in the same direction
as the movement of said conveyor belts and the rotational speed of ~he rollers
are positively controlled by means connected to the base of the device.
The present invention relates to an improvement over the above device.
According to the present invention there is provided an apparatus `~
for continuously stretching dough for cakes, bread and the like; comprising:
a base; a plurality of rollers spaced apart and rotatably positioned on said
base so as to travel along an oval path including a lower straight portion;
a plurality of conveyor belts below said rollers arranged in series, and hav-
ing upper flight portions which face said lower straight portion of said oval
path and are spaced from one another; means to drive said conveyor belts
relative to said base, with the upper flight portions moving in a common `
direction and the speed of each of said conveyor belts being faster than that
of the nearest upstream conveyor belt; and means connected to said base to
move said rollers in the same direction as the movement of the upper flight
portions of said conveyor belts; characterized in that adjacent conveyor belts
contact each other below the levels of the upper flight portions of the conveyor
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belts in the area where the upper flight portions o-f ~he conveyor bel~s ace
said lower straight portion o~ said oval path.
The apparatus of the present invention is effective in stretching
dough of high elasticity such as bread dough. The apparatus, by its structur-
al characteristics, can cause dough to yield without injuring it. Spillage
of flour attached to the lower surface of dough material moving on the convey-
or belts is substantially reduced by the contact between adjacent conveyor
belts. Preferably~ adjacent belts are arranged to contact each other at a
position underneath the upper flight of the upstream conveyor belt.
In the accompanying drawings which illustrate an exemplary embodi-
ment of the present invention:
Figure 1 is a diagramma~ic side view~ partially broken~ showing an
embodiment of an apparatus of the present invention and a dough feeder used
therewith;
Figure 2 is a diagrammatic cross-sectional side view of a conveyor
assembly associated with a roller assembly;
Figures 3 and 4 are diagrammatic views of movements of certain of
the components; and
Figure 5 is a cross-section of the drive mechanism for said roller
assembly.
Referring now to Figures 1 through 3, a dough feeder 1 is received
by a support 3 integral with the frame 5 of the apparatus. The power of a
drive motor 7 is transmitted through pulleys to reduction gears 9 of a vertical
output spindle type and reduction gears 11 o~ a hori~ontal output spindle type
simultaneously.
The output spindle 13 of the reduction gears 9 is operatively
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col~ected to an extruder (rlot sho~n) provided in the dough feeder 1 so that
dough material A is contiluously extruded therefrom.
The dough material A may be extruded in the form of a sheet, solid
rod or hollow rod as the case may be.
Dough material A thus ext~lded is received by a first conveyor belt
15 which is preferably inclined slightly upwardly in the downstream direckion.
The upper surface of the first conveyor belt 15 is strewn with ~lour 17 by a
flour feeder 19 molmted on the frame 5 at a suitable position upstream of the
dough feeder 1. Consequently, the extruded dough material A is laid on the
conveyor belt 15 strewn with flour.
Dough material A is then carried forward on the conveyor belt lS to
the apparatus B where it is stretched to a thin web by a group or rollers 51
co-operating with a conveyor assembly positioned thereunder consisting of a
plurality of conveyors 41, 43 and 45. `
The first conveyor 41 comprises the conveyor belt 15, which receives
dough material A extruded from the dough feeder 1. The conveyor 41 further
comprises a support plate 25 and three rollers. The support plate 25 supports
the upper flight of the conveyor belt 150 One of the three rollers, designated
by the reference number 31 in Figure 1~ is a drive roller, which moves the
conveyor bel~ 15 in the direction of the arrow asin Figure 2. The drive roller
31 is positioned underneath the support plate 25.
The second conveyor 43 has a similar str~cture as that oP the conveyor
41 and comprises a conveyor belt 21, a support plate 27 and three rollers. The
upper flight of the conveyor belt 21 is supported by the support plate 270
The upstream end of the support plate 27 is spaced apart from the downstream
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ond of the support plate 25 of the first conveyor 41. Thus, as illustrated
specifically in Figure 3, there is a gap D between the downstream end of the
upper flight o the conveyor belt 15 in the first conveyor 41 and th~ upstream
end of the upper flight of the conveyor belt 21 in the second conveyor 43. The
roller 33 is a drive roller, which moves the conveyor belt 21 in the direction
of the arrow b in Figure 3. The drive roller 33 is positioned underneath the
support plate 27. A tension roller 37 is positioned at the upstream end of the
conveyor 43 offset in the upstream direction from the support plate 27 and be-
low the level thereof. It is positioned such that a portion thereof comes
underneath the support plate 25 of the first conveyor 41 and, consequently,
underneath the upper flight of the conv~yor belt 15, interfering with the flight
of the conveyor belt 15 connecting the downstream end of the support plate 25
and the drive roller 31.
The third conveyor 45 has also a similar structure and comprises a
a conveyor belt 23~ a supRort plate 29 supporting the upper flight of the con
veyor belt 23~ and three rollers. The upstream end of the support plate 29 is
spaced apart from the downstream end of the support plate 27. The roller 35
is a dri~e roller, which moves the conveyor belt 23 in the direction of the
arrow c in ~ re 3 A tension roller 39 is positioned at the upstream end of
the conveyor 45 offset in the upstream direction from the support plate 2g and
below the level thereof. It is positioned such that a portion therof comes
underneath the support plate 27 of the second conveyor 43 and interferes with
the flight of the conveyor belt 21 co~lecting the downstream~end of the support
plate 27 and the drive roller 33.
The conveyor belt 15, after leaving the downstream end of the support
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plate ~5, turns around it and moves clownwardly in the dircction of the drive
roller 31 positioned underneath the support plate 25. The outer surf~ce of the
second conveyor belt 21~ turning around the tension roller 37 at the upstream
end of the conveyor 43, abuts on the outer surface of the con~eyor belt 15 of
the first con~eyor 41~ In the above positional relationship of the two conveyor
belts 15 and 21, they come into contact with each other at a position adjacent
to the peripheral surface of the tension roller 21 hi~ler than the level of the
center thereof. In other words~ the second conveyor belt 21 is in contact with
the first conveyor belt 15 after turning around the tension roller 37 upwardly
in the direction of the arrow b and facing upwards. Thus, the two conveyor
belts, where they contact each other~ are positioned in a vertically overlapping
relationship as illustrated at P. A similar positional relationship exists
between the conveyor belt 21 of the second conveyor 43 and the conveyor belt 23
of the third conveyor 45. h portion of the outer surface of the conveyor belt
23 comes into contact with a portion of the outer surface of the conveyor belt
21 at a position adjacent to the peripheral surface of the tension roller 39
after the conveyor belt 23 turns around the upstream end peripheral surface of
the tension roller 39.
In an alternative embodiment~ any two adjacent conveyor belts may
abut on each other at a position between their respective upper flights. In
this case the portion where the two conveyor belts abut should also be below
the level of the upper flights thereof. The downstream end of the upstream
conveyor belt may be supported by a separate support plate or a tension roller.
By the above manner of contact between adjacent conveyor belts, flour sprinkled
over the upper surface of the upper flight of the conveyor belt 15 can be
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satisfactorily transferred onto the succeeding conveyor belts, Flvur on the
first conveyor belt 15~ when dough material is transferred from the first
conveyor belt 15 to the second conveyor belt 21~ falls from the first conveyor
belt 15 in the absence of any support. However, if the second conveyor belt 21
is in contact with the first con~eyor belt 15 as in the present invention, flourg
after leaving the downstream end of the upper flight of the first conveyor belt
15~ falls onto the upper surface of the second conveyor be~t 21 moving slightly
upwardly in the direction of the upper flight of said con~eyor belt supported
by the support plate 27 thereunder. The arrow d represents the direction of
transfer of flour from the first conveyor belt 15 to the second conveyor belt
21. The arrow e represents the direction of the travel of flour on the second
conveyor belt 21. The pressurized contact between the first conveyor belt 15
and the second conveyor belt 21 adjacent to the tension roller 37 prevents flour
from passing between the two conveyor belts and falling, The same applies to
the transfer of flour from the second conveyor belt 21 to the third conveyor
belt 23.
The feed speed of the third conveyor 45 is higher than that of the
second conveyor 43, and the feed speed of the second conveyor 43 is higher than
that of the first conveyor 41.
In Figure 2, o~er and opposite to these conveyors 41, 43, 45, there
is the roller assembly c~mprising a number of rollers 51 which may revolve on
an oval path Y as described below. The rollers 51 are mounted by means of
bearings on their shafts 53 so as to be freely rotatable. A housing for the
rollers may be mounted to a base in any conventional way~
In Figures 4 and 5~ an endless chain 55 is entrained around two
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sprockets~ i.c., drive sprocket 57 and tension sprocket 59 spa~ed apart from
eaah other on a horizontal plane~ and is operated along an oval path oontaining
a lower straight portion. An additional endless chain 55 is entrained around
additional drive and tension sprockets. The two chains are parallel. The
drive sprockets 57 have drive shaft 65 in common, and the tension sprockets 59
have a tension shaft (not shown) in commonO At one end of the drive shaft 65
is provided bevel gear 69 which engages bevel gear 71. Shaft 67 of bevel gear
71 serves as the imput shaft for this apparatus. ~ttachments 61 are attached
to the chains 55, and serve to fix the ohains and the extensions 63 of the
shafts 53 to each other. The extensions 63 are thus caused to travel with the
chains 55 along the oval path Y. It will thus be readily understood that the
shafts 53, and consequently, hhe rollers 51 travel with the extensions 63. The
sprockets 57 are rotated by the shaft 65, which in^turn is rotated by the shaft
67 through bevel gears 69, 71. The shaft 67 is operatively connected to an
output spindle 73 of the reduction gears 11 through suitable means (not shown)
In ~`igure 2, the oval locus X formed by the path of the outermost
portions of the rollers 51 includes a lower straight po~tion x which is opposite
to the upper flighits of the conveyor belts 15, 21, 23.
The spacing between the straight portion x and the upper surfaces of
the upper flights of the conveyor be]ts is smallest at the downstream end of
the third conveyor belt 23 and gradually increases toward the first conveyor
belt 15. The spacing at the downstream end of the third conveyor belt 23 is
substantially equal to the thickness to which dough material is to be stretched.
As shown in Figures 4 and 5, a friction plate 75 is disposed at a
position along the lower straight portion x of the oval locus X such that it
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engages a portion of the outer cylindrical surface of roller 51 near one end
thereof so as not to obstruct the passage of the dough between the straight
portion x of the oval locus X of roller 51 and the conveyor belts lS, 21 and
23, and along the passageway of the dough. The friction plate 75 is attached
to a base for the apparatus by any conventionàl means, such as bolts or welding.
When roller 51 engages friction plate 75, the latter positivel~ controls ~he
rotational velocity of the former by friction therebetween. Both axial ends of
friction plate 75 are preferably ben~ somewhat upwardly. The forward bent
portion engages and starts to drive roller 51 somewhat be~ore roller 51 enters
the straight path portion facing the first con~eyor belt 15. Roller 51 is
driven to rotate around shaft 53 in the sense shown by the arrow y in Figures
2 and 3. The rearward end portion of friction plate 75 ceases to engage and
drive roller 51 somewhat after roller 51 leaves the straight path portion facing
the third conveyor belt 23, after completion of progress along the straight path
portion. This provides highly favorable effects on dough molding.
The arrow f represnets the direction of the ~r,avel of each shaft 530
The speed of the travelling motion of each shaft 53 is adapted to be higher
than the feed speed of the conveyor belt 230
In the operation of the apparatus, when the motor 7 is driven, the
output spindles 13, 73 are simultaneously rotated about their respective axes
through respective pulleys and reduction gears 9, 11. The axial rotation of
the output spindle 13 is transmitted to the extruder of the dough feeder 1 to
continuously extrude dough material A therefrom. The axial rotating power of
the ~utput spindle 73 is transmitted simultaneously to the input shaft 67 ofthe
roller assembly and to each of the aforesaid conveyors through a power trans-
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mission syst~m (no -t sho~n).
The dough materia]. A extruded from the dough feeder 1 is received on
the conveyor belt 15 strewn with f:Lour by a flour feeder 19 and conveyed to-
ward the apparatus of the present invention B,
In Figure 5, the rotation of the input shaft 67 causes the rotation
of the shaft 65 through the bevel gears 69g 71 thus causing a pair of sprockets
57 fixed around the shaft 6S to rotate. The rotation of the sprockets 57
causes a pair of chains 55 mounted in paraILel around the sprockets 57, 59 to
move in the direction of the arrow f. Thus, the rollers 51 connected to the
chains 55 travel along the oval path Y in the direction f. The path Y of the
chains 55, and consequently the rollers 51~ is of an oval formO
The rollers 51 travelling along the path Y, when they progress
along the straight portion x, come into contact at their circumferences with
the Priction plate 75 to cause themselves to forcibly rotate around the shafts
53 in the sense of the arrow y.
Underneath the above-described rollers 51, are positioned the first~
second and third conveyors 41, 43 and 45, the upper flights of which are ar-
ranged in series and Peed dough material in the direction of arrows a, b and
c, respectivel~r. Thus~ the dough material h conveyed forward on the conveyor
belt 15 is subjected to squashing action as shown in Figure 3.
If roller 51 is not caused to rotate around shaft 53 in the direction
y~ roller 51 would not be different from a conventional press roller~ except
for the fact that it is made to travel along the path Y. However, since roller
51 not only travels along the path Y but also rotates in the direction y
around shaft 53 when it progresses along the straight portion x, the surface
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of dough material A is subjected to a pressing action of roller 51 which comes
into contact with the dough material while it rotates around shaft 53.
Since roller St is in contact with dough material A while it ro-
tates about shaft 53 during its progress along the portion x, it distributes
the pressure on its ~urface to all points over the surface evenly. Thus,
dough material A adheres nunuma1ly to roller Sl and is eff0cti~ely stretched,
Ahead of each roller 51 in contact with dough material A appears a
bulging portion Al in the dough material A, When the bulge of the portion A
is large~ the dough sheet after stretching may have deep wrinkles or tears.
In the present case measures are taken so that such a bulging portion Al be-
comes minimal. First, the rotational speed of roller 51 around shaft 53 in
the direction y is controlled by the friction with the fixed fri¢tion plate
75 not by the friction with dough material A. The rotation of roller 51
around shaft 53 regulated by friction plate 75 is effective for reducing the
bulging portions A', since the rotational speed of roIler 51 relative to the
dough material A may be regarded as higher by the mo~i~g speed of dough mater-
ial A than the rotational speed thereof relative to a stationary object,
assuming the roller rotates at its stationary position. Second, the speed of
travel of roller 51 in the direc*ion f is higher than those of the conveyor
belts ~or transporting dough material. This also contributes to the decrease
of the bulge Al,
In addition to the above, the provision of the gap D fur*her assists
in decreasing the bulge. Dough material A is released from the first conveyor
belt 15 at the downstream end of the b~lt conveyor 41 and the pressing action
of roller 51 does not act on dough material at the gap D, and so roller 51 can
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reaclily pass OVel` the buLge Al and exert light contact pressure upon the top
of the bulge while passing thereover. Also, the speed difference between the
conveyor belts 15 and 21 strctches the dough material in the gap D. When the
gap D is very short, the speed difference between the two conveyor belts is
concentrated on the narrow portion of dough material, thus resulting in possi-
ble rup-ture of the dough, The gaR D is preferably 20 mm or longer. However~
a gap of more than 70 Imm may cause wrinkles in the dough material.
Dough material is most effectively stretched when it can slide on
the surfaces of the belts, ~hen dough material sticksto ~h~lbelt~ cannot
slide on the belts but the upper portion thereof is merely displaced relative
to the lower portio~ thereof, and thus the dough material cannot be effecti-
vely stretched. Accordingly, it is desirable for the surfaces of the belts to
be provided ~ith a moderate amount of flour thereby to be kept under a slid-
able condition. In the present apparatus, the surface of the conveyor belt
15 which faces downwards after tur~ng at its downstream end is made to come
into contact (at the position P) with the surface of the conveyor belt 21
which faces upwards after turning around the tension roller 37 at its upstream
end Conse~uently excessive flour on the surface of the conveyor belt 15 is
scraped off and transferred onto the surface of the conveyor belt 21, thus
avoiding loss of flour so that the slidability of dough material on the isecond
conveyor may be maintained.
In order to obtain the optimal sliding effect, a plurality of con-
veyors are provided underneath the rollers 51~ which conveyors are arranged
such that a downstream conveyor has a greater feed speed than that of any of
upstream conveyors. The speedso~f these conveyors are adjusted to correspond ;
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to or ~lightly o~ceed the stretching rat~ of the dough The length of the
support plate 27 and the portion of each of the support plates 25 and 29
f~cing the str~ight portion x should also be ~djusted. Xf a support plate
facing the straight portion x was excessively longg dough material would be-
come likely to stick to the upper sur~ace of the oo meyor belt because
stretching tends to expose portions of dough not sufficiently covered with
flour. The lower surface of the dough material and the upper surface of the
conveyor belt should always be in a sliding relationship.
The stretching effect is enhanced when the number o~ rollers on the
oval path Y is increased. When the interval between any pair of adjacent
rollers is arranged to be shorter than the length of any intermediate conveyor
plate, even a dough material of elastic character such as bread ddugh can be
effectively stretched. The reason for this is that the dou~t material is
held in a stretched condition by a pair of adiacent rollers for a certain
length of time whereby the dough yields~ reducing its elasticity and it re-
covers little of its thickness before stretching~ Since the rollers S1 pro-
gress along the path Y faster than the feed speed of any of the conveyor
belts, all portions of the dough material are pressed repeatedly by different
progressing rollers. The repetition of the abo~e pressing operation effecti-
vely stretches a dough material of elastic character.
Thus~ the dough material A may be stretched to a thit~ strip such as
of a thickness of l mm through the stretching operation of the apparatus
before it leaves the downstream end of the apparatus.
According to a test conducted using a dough material consisting of
a mixture of by weight, 30 parts of egg, 50 parts of sugar and 100 parts of
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~heat flour~ the dough material was fed to ~he apparatus :in the form of a
sheet 50 mm thick. The dough material was stretched to a thickness of 1 mm
in one operation. The stretching ef~iciency in terms of the orginal thickness
against the resulting thickness was 50.
Further, an apparatus of a similar structure~ except that brush
rollers are provided between each adjacent pair of conveyor belts as disclosed
in the previously referred to Canadian patent application No. 217,374, was
employed to stretch dough material. The apparatus failed to stretch dough
material to a thickness of 2 mm in one operation without causing injury to the
stretched dough material. The difference in efficiency between the above ap-
paratus and the apparatus of the present invention apparently results from
the presence of the brush rollers~ When the prior art apparatus was operated
continuously for a substantial length o~ time, the brush rollers were clogged
with flour to lose the flexibility of brush bristles. This prevented the
portion of dough at the gaps D from being sufficiently stretched.
Although the preferred embodiment of the present invention has been
illustrated and described, it will be apparent to those skilled in the art
that ~arious changes and alterations may be made therein without departing
from the spirit of the invention and the scope of the appended claims. ~or
instance, the conveyor assembly may contain a greater number of conveyors
In fact~ if more conveyors are employed opposite to the straight portion of
the locus of the rollers, a higher efficiency may be obtained.
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