Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
MASA SHEETING APPARATUS
BACKGROUND OF THE INVENTION
The present invention relates to masa sheeting apparatus and,
more particularly, to such apparatus in which a wire is employed to
peel the masa sheet from the sheeting rollers.
Masa sheeting machines are used in the production of thin
corn products formed from unleavened cornmeal dough such as tor-
tillas and tortilla chips. These machines have for decades com-
prised a pair of sheeting rollers positioned beneath a hopper. The
masa squeezed between the rolls forms a sheet which adheres to the
rollers by a wire so ~hat the entire sheet is carried by the second
roller. A cutting device actingiagainst the second roller outlines
product pieces in the sheet. A second peeling wire is provided to
strip the masa sheet and the product pieces from the second roller
after the cutting operation. The product pieces fall onto a take-
away conveyor, but the scrap portions of the sheet are carried
along with the roller back into the hopper by thin hoops ~itted to
the roller.
The second roller is provided with spaced circumferential
grooves in whlch the hoops are loosely positioned. The hoops
are formed in place from bands having adjustably interlocking
ends, The formed hoops have a diameter slightly less than that
of the roller so that they remain captive within the grooves.
The grooves are sufficiently deep to allow the hoops to assume
eccentric positions in which they protrude from the grooves a
significant distance,
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As the masa sheet is formed between the sheeting rollers,
the masa is pressed against the hoops as well as the cylindrical
surfaces of the rollers. Therefore, the masa sheet adheres
to the hoops also. The second peeling wire is threaded
through the hoops so that as the wire peels the masa sheet
from the surface of the roller the sheet continues to adhere
to the hoops and the cut pieces are severed from the sheet
and fall onto the take-away conveyor as the sheet is æeeled
from the roller, but the remainder of the sheet (the scrap)
is carried by the hoops back into the hopper. For the decade~
that this type of machinery has been in operation, piano wire
or similar high tensile strength round wire has been used
exclusively as the peeling wires. The preferred wire size
is .014 inc'n in diameter. wire of .016 inch diameter
is also used, although it does not peel as well as the thinner
wire. Over these decades of use, there has been a consistant
pattern of breakage of the peel wires. The wires used to ~eel
the cut masa sheet from the second sheeting rollers break
after an average of about 8 hours of use. The wires used to
peel the masa sheet from the first sheeting rollers brea~c
after an average of about 32 hours of use. Each machine has
a double set of sheeting rollers and, therefore, on the average
2! wires must be replaced per machine during each ei~ht-hour
work shift. Replacement of each wire requires 15 to 20 minutes,
during which time the machine is inoperative. Therefore, up
to 50 minutes of an eight-hour shift is conventionally lost.
Therefore, on the average, each machine is idle for 30
to 50 minutes during each eight-hour shift with a resulting
loss of up to 10~ of production.
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SUMMARY OF THE INVENTION
One embodiment of this invention provides an improve-
ment in masa sheeting apparatus. The apparatus includes a
hopper for receiving masa, first and second driven rollers
positioned beneath said hopper in closely spaced relation-
ship to form a masa sheet, means for separating said masasheet from said first roller, a cutting member acting
against said second roller for cutting said masa sheet, a
take-away conveyor, and a tensioned wire extending along
the surface of said second roller above said second roller.
The improvement comprises said second tensioned wire being
a flat band having a width and a thickness, the widthwise
surface thereof being held flat against the surface of
said second roller.
In another embodiment the apparatus comprises a hopper
for receiving masa, first and second driven rollers posi-
tioned beneath said hopper in closely spaced relationship
to form a masa sheet, means for separating said masa sheet
from said first roller, said second roller having spaced
circumferential grooves and hoops loosely positioned in
said grooves, said hoops having an outside diameter about
equal to that of said second roller between said grooves,
a cutting member acting against said second roller for
cutting said masa sheet between said grooves, a take-away
conveyor, and a tensioned wire passing through said hoops
and extending along the surface of said second roller
above said take-away conveyor for separating said cut masa
sheet from said second roll. The improvement comprises
said second tensioned wire being a flat band having a
width and thickness, the widthwise surface thereof being
held flat against the surface of said second roller.
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BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention has been
chosen for purposes of illustration and description and
is shown in the accompanying drawings, forming a part of
the specification wherein:
Fig. l is a side elevational view illustrating the
general arrangement of a masa sheeting apparatus embody-
ing the present invention;
Fig. 2 is an elevational view taken along line 2-2
on Fig. l;
Fig. 3 is a sectional view taken along line 3-3 on
~ig. 2;
Fig. 4 is a sectional view taken along line 4-4 on
Fig. l;
Fig. 5 is a view taken along line 5-5 on Fig. 4;
Fig. 6 is a view taken along line 6-6 on Fig. 4;
Fig. 7 is a schematic sectional view taken along the
line 7-7 on Fig. 2 and illustrating the general operation
of the masa sheeting apparatus.
Fig. 8 is an enlarged view of a portion of Fig. 7,
illustrating the peeling wire of the present invention
in operation.
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DESCRIPTIO~ OF THE PREFERRED E'IBODI~lENT
Referring to the drawings in detail there is shown a
masa sheeting machine l0 embodvin~ the ~resent invention.
The sheeter 10 is a dual machine, having two essentially
identical assemblies located side by side within a single
frame structure. For purposes of simDlicity, only one
assembly is shown in the drawin~s except in Fig 2 where
a portion of the second assemblv is illustrated. Also for
purposes of simplicity, only those elements of the machine
are shown which must be described in order to impart a full
understanding of the invention; for example, the conventional
gear train used to drive the elements of the machine is not
disclosed.
The masa sheeting machine 10 includes side frame plates
11 (one of which is shown) and a center frame plate 12 (Fig 2)
which together support the elements that make up the two
assem~lies.
The assembly shown, comprises a hopper 14, a pair of
sheeting rollers 15 and 16, a rotary cutter 14, and a take-
away conveyor 1~.
The roller 15 has a smooth uninterrupted cvlindrical
surface and is mounted on an axial shaft that is journalled
on one end in a bearing 20 carried by the frame plate 11
and on the other end in a bearin~ (not shown) carried by the
center frame plate 12. The second roller 16 is joined by
a thick shaft 21 to the second roller 22 of the other sheeting
assembly. A short shaft 24 extending from the roller 16 is
journalled in a bearing 25 positioned in the frame plate 11.
~ similar arrangement (not shown) is provided on the opposite
end of the roller 22 to complete the supporting arrangement
of the dual rollers 16 and 22.
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The conveyor 19 includes a roller 26 extending between
the center frame plate 12 and the side frame plate 11, and
journalled in bearings 27 mounted in the frame plates. An
endless conveyor band 29 extends from the roller 26 to a
second roller 30 (F'ig 7) to carry the product to the next
production operation.
The second roller sheeting 16 is formed with spaced
circumferential grooves 31 o~ generally rectangular cross-
section, as shown in Fig 34. In each of these grooves a
thin steel hoop 32 is positloned. The hoops are formed in
place from bands having adjustably interlockinq ends. The
hoops are formed to have a diameter slightlY less than that
of the roller 16 so that thev remain captive within the
grooves.
The frame plate 11 is provided with a recess 34, extending
along the edge of the roller 16 and an oT~ening 35 adjacent
the edge of the roller 15. Peeling wire tensioning mechanisms
36 and 37 are mounted on the outer surface of the frame ~late
11 adjacent to the recess 34 and the opening 35 respectively.
Referring to Fig 2, a oeeling wire 40 extends from a
peg 41 mounted on the center frame olate along the surface
of the roller 16 in a gentle spiral to the tensioning mechanism
36. The peeling wire 40 passes through the hoops 32 as shown
in Figs 2, 3, 4, and 8. At the point where the wire 40. passes
under each hoop, the hoop protrudes from the groove 31.
The tensioning mechanisms 36 and 37 each include a guide
plate 42, a blo,ck 44 perpendicular to the plate 42, a
tensioning peg 45 extending through the block and having a
worm-drive gear 46 mounted on the end thereof, and a hand
operated worm gear 47 havinq a shaEt 49 and handle 50 connected
thereto.
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The gulde plate 42 is formed with a n~lmber of slots 51
therein and when the peelin~ wire 40 is installed it is set
into one of these slots and then wrapoed around the tensioning
pet 45. The handle 50 is used to drive the worm gear 47 and
rotate the peg 45 to tension the wire sùfficientl~ to produce
a good neeling action, a very stic~y masa requiring more
tension than a drier masa.
In accordance with the present invention the peelin~
wire 40 has a flat band form and is installed so that the
large widthwise surface lies flat against the cylindrical
surface o~ the second roller. In the Dreferred embodiment, the
flat band is formed by rolling a round wire and, therefore,
the band has rounded edges as shown in Fig ~.
The slots 51 are enlarged to receive the width of the
peeling wire band. The band is laid flat in the slots 51
and twisted 90 degrees before being wrapped around the tensioning
peg 45.
Another flat wire band 52 (see Fig 3) extends along the
surface of the first sheeting roller 15 between an attachment
(not shown) provided on the center frame olate 12 and the
tensioning mechanism 3'. As shown in Fig 7, the masa sheet
formed by the sheeting rolls 15 and 16 is peeled from the
roller 15 by the peeling wire 52. The rotary cutter cuts product
pieces from the masa sheet, however, both the cut pieces and
the remainder of the sheet continue to adhere to the surface
of the roller 16 and to the outer surfaces of the hoops 32.
As shown in FicJ 8, the peeling wire 40 separates the cut product
~ieces and the remainder of the sheet from the surface of the
roller 16. The oroduct pieces fall onto tl-e take-away convevor
19. The scrap masa sheet however continues to adhere to the
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surface of tne hoops 32 which are protruding from ~heir grooves.
The hoops thus carry the scrap masa sheet back into the hooper.
In the sheeting machine 10, the roller 16 has a diameter
of about 6.5 inches and a length of about 15 inches. Peeling
wire bands of stainless steel having a thickness of .010 inch
and a width of .062 inch were installed in the sheetinq machine
and the machine was operated in a noncommercial test run held
under normal production conditions for one eight-hour shift per
day, five days a week, for two weeks. During this two-week
period not a single peeling wire broke or was replaced for any
reason. During such a period, if prior art peeling wires were
used, it would have been necessar~ to replace 20 wires on the
second rollers and several on the first rollers. In addition
the wire bands 40 and 52 peeled the masa sheet from the rollers
15 and 16 more throughly than did the Drior art round piano wires.
1`he invention is not limited to masa sheeting machines
with rollers of a particular size. Other masa sheeters have
rollers of ~ inch and 10 inch diameter. The present invention
will provide the same efficacious results on machines with
rollers of these or greater dimensions.
It will be seen from the foregoing that the present
invention provides an improvement in ~asa sheeting apparatus
which severlv reduces lost production time resulting from the
replacement o~ peeling wires.
