Food or edible material: processes – compositions – and products – Processes – Treatment or preparation of farinaceous dough – batter – or...
Reexamination Certificate
1999-08-04
2001-07-31
Nguyen, Nam (Department: 1722)
Food or edible material: processes, compositions, and products
Processes
Treatment or preparation of farinaceous dough, batter, or...
C426S389000, C425S136000, C425S223000, C425S230000, C425S310000, C425S363000, C425S4360RM, C242S412100, C242S420000, C242S420500, C242S421400
Reexamination Certificate
active
06268005
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an improved sheeter wire apparatus and, in particular, to a sheeter wire apparatus which provides for a continuous advancement of sheeter wire using a simple design that provides constant tension on the feed spool even during wire breakage. This is accomplished by the use of a drag motor connected to the supply spool, a constant speed motor connected the take-up spool, and a feed spool tension device.
2. Description of Related Art
A sheeter is a device commonly used in the food industry for making flattened food products, such as tortilla chips, in a continuous processing operation. Typically, a dough product is compressed between a pair of counter rotating sheeter rollers that are located closely together, thereby providing a pinch point through which the dough is formed into sheets. The dough can then be cut by, for example, a cutting roller to form the shape of the product desired.
Many dough products, particularly those that are corn based (“masa”), have a tendency to stick to the sheeter rollers rather than dropping onto a conveyer for transportation to the next processing step, such as a baking oven. One common approach to this problem is to string a stripper wire across the face of the sheeter roller so that the stripper wire can scrap away the dough product off of the surface of the roller.
An example of a prior art design in this regard is illustrated by FIG.
1
.
FIG. 1
is a perspective view of the output of a dough sheeter device
110
. The cut dough product, in this case uncooked tortilla chips
120
made from masa, can be seen on a conveyer
130
after being deposited on the conveyer
130
by a sheeter roller
140
. The sheeter roller
140
will typically have plurality of plastic bands
150
about the circumference of the sheeter roller
140
. These bands
150
ride in groves (now shown) in the sheeter roller
140
and hold the sheeter wire
160
close to the surface of the sheeter roller
140
. The bands
150
also provide a surface for returning ribbons of unused masa to the sheeter
110
. A sheeter wire
160
is shown strung across the face of the sheeter roller
140
. This sheeter wire
160
is attached to two fixed points
170
,
180
and is threaded across the face of the sheeter roller
140
underneath each of the bands
150
. This provides a flush contact between the sheeter wire
160
and the surface of the sheeter roller
140
.
Also shown is a tension device
190
, which can be a hydraulic or pneumatic device that provides a constant tension on the wire
160
. This tension device
190
is typically connected to a warning device to provide an indication of wire breakage. Alternatively, the tension device
190
can also act as the second fixed point, thereby eliminating the post
180
shown in FIG.
1
.
FIG. 1
shows the sheeter wire
160
on the front or open side of the sheeter roller
140
. The sheeter wire
160
can also be located in the same relative vertical position but on the back, or concealed, side of the roller
140
.
The sheeter wire
160
is typically commercial piano wire. A typical tension on the wire during operation is 100 to 125 pounds. Contact with hardened masa, particularly during start-up, can subject the sheeter wire
160
to higher tension for short time periods. During operation the wire is also subject to friction from the moving face of the sheeter roller
140
. The wire
160
must be replaced periodically or it is prone to breakage after time. In fact, in a continuous use operation for a typical sheeter device producing tortilla chips, it has been observed that such fixed sheeter wire
160
will break, if not replaced, nearly daily.
In order to replace a broken sheeter wire
160
the entire sheeter device
110
and, consequently, the entire chip processing assembly, must be stopped. The old sheeter wire
160
is removed. A new sheeter wire
160
is attached to the first attaching point
170
, strung across the face of the sheeter roller
140
under the bands
150
, and attached to a second attaching point
180
. Then the tension device
190
must be reactivated. Raw material is lost because the dough that was on the sheeter must be thrown away and additional product downstream my need to be discarded. In addition, line start-up procedures must be initiated, which usually results in the loss of further product. A wire breakage event, therefore, results in a substantial amount of unscheduled downtime and lost product. The alternative is to schedule, on a daily basis, the replacement of the sheeter wire
160
. A scheduled replacement of the sheeter wire
160
, however, results in even more frequent, although scheduled, downtime.
One attempt at addressing the wire breakage problem is reflected in U.S. Pat. No. 5,720,990 (“Lawrence”) issued on Feb. 24, 1998. The Lawrence patent discloses a wire separator system for a sheeter device comprising a motor that drives a feed spool and a motor that drives a take-up spool. Tension is maintained on the sheeter wire by use of a tension sensing pulley providing input to a controller which modulates the torque on the take-up reel. Provided that the wire does not unexpectedly break, the Lawrence patent discloses a device that will allow the sheeter to run for long periods of time without the necessity of stopping the sheeter to replace the sheeter wire, because new wire is constantly drawn across the contact surface.
The invention disclosed by Lawrence has several drawbacks, however. First, the design assumes that the wire will not break during operation. Unfortunately, this is not a safe assumption. In fact, it is not an infrequent occurrence that wire breakage occurs on the prior art model illustrated by
FIG. 1
shortly after a new wire has been installed. This could occur due to a sudden contact with a dried piece of dough that has become affixed to the sheeter while the sheeter is stationary. Further, an initial steady-state friction between the sheeter wire and the sheeter must be overcome at the instant the sheeter begins to rotate. Since the Lawrence device provides that one motor feeds wire while another motor takes-up wire, a breakage between the two motors can result in the continued feeding of wire into the sheeter until the feed motor comes to a stop. A breakage also results in a loss of tension on the feed spool and can lead to unraveling or the “weed eater” effect, whereby the spool becomes unwound. Further, the Lawrence device is designed to maintain constant tension of the wire by using a variable speed pulling motor connected to the take-up reel. Since the Lawrence feed spool is connected to a fixed speed motor, the tension will necessarily fluctuate at the point that the wire is leaving the feed spool when, for example, the wire encounters a piece of dried dough product on the sheeter during operation. These torque fluctuations could effect the consistency of the feed spool's wound tension, thereby leading to further torque fluctuations and potential feed problems.
Consequently, a need exists for an improved continuous sheeter wire apparatus that maintains a constant tension on the feed spool even during wire breakage. This apparatus should be designed, in a fail safe way, to avoid driving sheeter wire into the sheeter after a wire breakage. The improved apparatus should also be of a relatively simple design with a minimum number of necessary and washable components.
SUMMARY OF THE INVENTION
The proposed invention comprises an improved continuous sheeter wire apparatus that uses a drag motor to control constant tension on the feed spool and a constant velocity motor driving the take-up spool. The invention also incorporates pinch rollers on the feed spool to insure that, even during wire breakage, constant tension is maintained.
In use, the constant speed motor pulls wire onto the take-up spool. Constant tension is maintained on the sheeter wire by the torque of the drag motor connected to the feed spool. Since tension is controlled at the feed end of the device, as opposed to the take-up
Cahoon Colin P.
Carstens, Yee & Cahoon
Heckenberg Donald
Nguyen Nam
Recot Inc.
LandOfFree
Sheeter wire apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sheeter wire apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sheeter wire apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2519898