Controlled depth cutting method and apparatus

Tape (100) being laid by a tape laying machine (2) is transported by a continuous strip of backing paper (102). A rotary cutter (12) is mounted on one arm (36) of a C-shaped frame (34). An anvil (20) is mounted on the other arm (38). Frame (34) moves laterally to move cutter (12) and anvil (20) laterally across tape (100) with tape (100) and paper (102) therebetween. A single point on anvil (20) supports the portion of tape (100) being cut throughout the length of the cut. Therefore, an essentially constant distance between cutter (12) and anvil (20) is maintained to completely sever tape (100) without severing paper (102).

DESCRIPTION 
1. Technical Field 
This invention relates to methods and apparatus for cutting strip or sheet 
material and, more particularly, to such a method and apparatus in which a 
laterally moving cutter cuts only the top layer of a double layer and in 
which the lower layer is protected from being cut by accurately 
controlling the depth of the cut. 
2. Background Art 
This invention is directed primarily toward providing an improved cutting 
system for use in tape laying machines. Such tape laying machines are 
known in the art and are used for manufacturing aircraft structures from 
composite tape materials. An example of a type of tape laying machine into 
which the method and apparatus of the present invention could 
advantageously be incorporated is the machine developed by the Vought 
Corporation and described in the Jan. 24, 1983 issue of Design News, in 
the article on pages 136 and 137 entitled "CNC Machine Slashes Laminated 
Composite Cost". 
The composite tape materials used in conjunction with automatic tape laying 
machines for manufacturing aircraft structures are normally provided in 
double layer form. The top layer is the composite material itself, and the 
bottom layer is backing paper. The purposes of the backing paper include 
preventing the sticking together of layers of the composite material in 
rolls of the tape, preventing resin build-up on machine parts, and 
providing a continuous strip for transporting the tape from the supply 
reel. Because of the last named purpose, it is of course necessary to 
avoid cutting through the paper when the top layer of composite tape 
material is cut. 
A problem that is encountered with known methods for cutting the top layer 
is that, because the backing paper is only a few thousandths of an inch 
thick, it is extremely difficult to cut the top layer of composite tape 
material to the last fiber and leave the backing paper sufficiently intact 
to provide uninterrupted transport of the tape material. In known tape 
laying machines with cutting means that moves laterally across the tape, a 
stationary anvil is provided to support the tape material and backing 
paper across the width of the tape while a lateral cut is being made. In 
order to maintain an essentially constant depth of the cut, it is 
necessary to have an essentially constant distance between the cutting 
blade and the anvil. Therefore, it is necessary for the lateral movement 
of the cutter to be essentially parallel to the surface of the anvil 
facing the cutter. This near perfect parallel relationship is extremely 
difficult if not impossible to attain and maintain. Any imperfections on 
the anvil surface due to imperfect manufacture or uneven wear and any play 
in the movement of the cutter will affect the depth of the cut being made. 
The resulting imperfections in the depth control of the cut can lead to 
tape fibers escaping being cut or cutting of the backing paper of a 
sufficient magnitude to impair its ability to transport the tape. 
The undesirability of such missed fibers should be obvious. If they are not 
detected in time, they will be pulled along with the backing paper as the 
tape laying head moves into position to lay the next course. This ruins 
the course of composite material that has just been laid. The machine has 
to be stopped and the damaged composite material must be removed before 
the tape laying process can be resumed. This results in considerable 
additional expense due to increased personnel costs, wasteful downtime of 
an expensive tape laying machine, and waste of the damaged composite 
material which must be discarded. Even if the missed fibers are detected 
in time, the cost of the operation is still significantly increased. The 
machine must be stopped to allow the missed fibers to be cut by hand. 
Again valuable machine time is lost and personnel costs are increased. The 
machine operator has idle time and at least one extra worker is required 
just to watch for missed fibers, shut down the machine as necessary, and 
hand cut missed fibers. In addition to the increased cost, the hand 
cutting process has the added disadvantage of being relatively imprecise, 
resulting in a lessening of the quality of the finished composite 
structure. 
The undesirability of cutting the paper should also be obvious. If the cuts 
in the paper are extensive enough to impair the transport of the tape by 
the backing paper, the machine has to be stopped to repair the damaged 
portion of the backing paper. This again results in considerable 
additional expense due to increased personnel costs, wasteful downtime of 
an expensive tape laying machine and waste of composite tape material that 
cannot be laid by the machine because it must be advanced beyond the tape 
laying head to insure that the take up reel securely engages the backing 
paper. 
The depth of the lateral cut in the tape needs to be controlled within very 
narrow tolerances. Areas of the cuts that are either too shallow or too 
deep lead to the severe disadvantages described above. Therefore, the 
primary object of the present invention is to provide a method and 
apparatus for accurately controlling the depth of such cuts to thereby 
decrease the cost of the tape laying operation and improve the quality of 
the finished product. 
The following United States patents each disclose a rotary cutter for 
cutting a layer of material: 
U.S. Pat. No. 2,217,923, granted Oct. 15, 1940, to A. I. Silverman; 
U.S. Pat. No. 2,367,432, granted Jan. 16, 1945, to F. Reprogle; 
U.S. Pat. No. 2,571,527, granted Oct. 16, 1951, to M. Boyer; 
U.S. Pat. No. 2,617,186, granted Nov. 11, 1952, to J. A. Pickles; and 
U.S. Pat. No. 3,224,092, granted Dec. 21, 1965, to D. W. Nagel. 
Each of these patents, except Nagel, discloses a cutter for cutting plaster 
casts to remove them from a patient. Nagel discloses a cutter for cutting 
excess material off of carpet during the installation process. Each of the 
devices described in these five patents includes a guard or spacer member 
that moves with the rotary cutter under the layer of material to be cut so 
that such layer is between the rotary cutter and the guard or spacer 
member. The layer of material between the cutter and the guard or spacer 
member is cut all the way through. 
The following United States patents each disclose apparatus in which a 
rotary cutter or marking tool is employed to process a single layer of 
material that is positioned between the cutter or tool and a support 
member, and in which the cutter or tool and/or the support member is 
stationary: 
U.S. Pat. No. 1,059,200, granted Apr. 15, 1913, to G. W. Parkinson et al; 
U.S. Pat. No. 2,291,809, granted Aug. 4, 1942, to A. L. Jackson; 
U.S. Pat. No. 3,143,023, granted Aug. 4, 1964, to K. G. S. Addin; and 
U.S. Pat. No. 4,210,052, granted July 1, 1980, to A. R. Fisher. 
U.S. Pat. No. 2,066,752, granted Jan. 5, 1937, to S. B. Ward discloses a 
C-shaped gauge that is used to find radial holes in a metal cylinder that 
has a rubber jacket. U.S. Pat. No. 3,807,261, granted Apr. 30, 1974, to J. 
M. Couvreur discloses apparatus for scoring or cutting sheet material such 
as glass. The scoring or cutting tool moves laterally across the glass 
which is supported on a bed that is either stationary or moves 
longitudinally to advance the glass in a direction generally perpendicular 
to the direction of movement of the scoring or cutting tool. U.S. Pat. No. 
4,118,268, granted Oct. 3, 1978, to E. Price discloses apparatus in which 
a rotary cutter is used to cut a layer of surfacing material that is held 
in position to be cut by a support fence that is urged against a surface 
perpendicular to the layer of surfacing material. Both the cutter and the 
supporting fence appear to be stationary, and the layer of surfacing 
material being cut is moved past the cutter. 
U.S. Pat. No. 3,977,055, granted Aug. 31, 1976, to M. W. Gilpatrick; U.S. 
Pat. No. 4,130,042, granted Dec. 19, 1978, to C. F. Reed; and U.S. Pat. 
No. 4,217,693, granted Aug. 19, 1980, to H. H. Roder et al each disclose 
apparatus for controlling the depth of a cut or score in a layer of 
material. Gilpatrick discloses a cutter for cutting loops in fabric. The 
cutter includes a circular rotating member with a number of 
circumferentially spaced blades projecting from its outer circumference. 
The backing of the fabric is protected from being cut by a number of 
guards extending radially outwardly from the circumference of the circular 
member parallel to the blades. Reed discloses a die cutter assembly for 
cutting label material without cutting the backing strip. The assembly 
inclues a precisely machined die cutting roll and an anvil roll both of 
which rotate and the spacing between which is controlled by a pair of 
bearings. Roder et al disclose a controlled depth scoring tool for scoring 
composite labels of the type commonly used on cylindrical packages of 
ready-to-cook biscuits. The width of the blade portion that is allowed to 
penetrate the label is controlled by a collar that is concentric with and 
adjacent to the rotary cutter. 
The above patents and the prior art that is discussed and/or cited therein 
should be studied for the purpose of putting the present invention into 
proper perspective relative to the prior art. 
DISCLOSURE OF THE INVENTION 
A subject of the invention is apparatus for making a cut in sheet material 
along a cutting path while maintaining along said path an uncut layer of 
said material of essentially constant thickness. According to an aspect of 
the invention, the apparatus comprises frame means having opposed first 
and second portions positioned to move along said path. Cutting means is 
mounted on the first portion to move with said first portion along said 
path. An anvil is mounted on said second portion facing the cutting means 
to move simultaneously with said first and second portions and the cutting 
means along said path and to support the sheet material when said material 
is being cut. When a cut is being made, said first and second portions 
move along said path with said material therebetween. The simultaneous 
movement of the cutting means and the anvil maintains a single point on 
the anvil supporting the portion of the sheet material being cut 
throughout the length of the cut. This maintains an essentially constant 
distance beween the cutting means and the anvil to thereby maintain along 
the cutting path an uncut layer of said material of essentially constant 
thickness. 
According to another aspect of the invention, the frame means comprises a 
rigid generally C-shaped frame having a center portion and two opposed 
spaced-apart arms projecting generally perpendicularly outwardly from said 
center portion. These arms include said first and second portions of the 
frame means. Preferably, the apparatus further includes drive means for 
moving said frame to move said first and second portions along said path. 
The apparatus may also include certain preferred features. One such 
preferred feature is cutting means that comprises a rotary cutting blade. 
Another such preferred feature is an anvil that includes a rounded support 
surface facing the cutting means, said surface having an apex forming a 
support point for the portion of the sheet material being cut by the 
cutting means. 
Another subject of the invention is an improved cutting apparatus for 
making lateral cuts through tape in a tape laying machine of the type in 
which a tape to be laid is transported by a continuous strip of backing 
material. According to an aspect of the invention, the apparatus comprises 
frame means having opposed first and second portions positioned to move 
laterally across the tape. Cutting means is mounted on said first portion 
to move with said first portion laterally across the tape. An anvil is 
mounted on said second portion facing the cutting means to move 
simultaneously with said first and second portions and the cutting means 
laterally across the tape and to support the tape and backing material 
when the tape is being cut. When a lateral cut through the tape is being 
made, said first and second portions move laterally across the tape with 
the tape and the backing material therebetween. The simultaneous movement 
of the cutting means and the anvil maintains a single point on the anvil 
supporting the portion of the tape being cut throughout the length of the 
cut. This maintains an essentially constant distance between the cutting 
means and the anvil to thereby maintain an essentially constant depth of 
the cut and completely sever the tape without severing the backing 
material. 
According to a preferred aspect of the invention, the frame means comprises 
a rigid generally C-shaped frame having a center portion and two opposed 
spaced-apart arms projecting generally perpendicularly outwardly from said 
center portion. These arms include said first and second portions of the 
frame means. Preferably, the apparatus further comprises drive means for 
moving said frame to move said first and second portions laterally across 
the tape, said drive means comprising ball screw drive means. 
According to another preferred aspect of the invention, the cutting means 
comprises a rotary cutting blade. Preferably, the apparatus further 
comprises cutter drive means for rotating said cutting blade at a 
sufficiently high rate to ensure that a maximum radius portion of the 
blade comes into cutting contact with each portion of the tape being cut. 
Rapid rotation of the cutting blade makes it possible to make the cut 
relatively quickly without sacrificing the completeness of the cut. 
According to another aspect of the invention, the apparatus further 
comprises a guide surface along which the tape and backing material move 
into position for the tape to be cut by the cutting means. This guide 
surface includes two longitudinally spaced longitudinal sections defining 
a gap therebetween in which the anvil moves. The anvil is positioned to 
extend slightly out of the gap toward the cutting means. 
According to another preferred aspect of the invention, the anvil includes 
a rounded support surface facing the cutting means. This surface has an 
apex forming a support point for the portion of the tape being cut by the 
cutting means. 
Still another subject of the invention is a method of controlling the depth 
of lateral cuts through tape to completely sever the tape without 
impairing the transport of the tape in a system in which tape in a tape 
laying machine is transported by a continuous strip of backing material 
and in which said machine has cutting means for making lateral cuts 
through the tape and support means for the tape and backing material. 
According to an aspect of the invention, the method comprises moving the 
tape and the backing material between the cutting means and the support 
means into position for the tape to be cut by the cutting means. The tape 
is cut by the cutting means, and the portion of the tape being cut and the 
backing material are supported by the support means. While cutting the 
tape and supporting said portion of the tape and the backing material, the 
cutting means and the support means are moved simultaneously laterally 
across the tape and the backing material to maintain an essentially 
constant distance between the cutting means and the support means. This 
maintains an essentially constant depth of the cut and completely severs 
the tape without severing the backing material. 
Tape laying machines constructed according to the present invention solve 
the problem described above of maintaining depth control that is 
sufficiently accurate to cut the top layer of composite tape material to 
the last fiber and leave the backing paper sufficiently intact to provide 
uninterrupted transport of the tape material. By providing a solution to 
this problem, the present invention avoids all of the disadvantages 
discussed above relating to tape fibers escaping being cut or cutting of 
the backing paper of a sufficient magnitude to impair its ability to 
transport the tape. A course of tape just laid by the tape laying machine 
is completely severed so that it will not be disturbed by movement of the 
tape laying head into position to lay the next course. Therefore, there is 
no need to have an extra worker present to watch for fibers missed by the 
cutting means and no need to shut down the machine to cut missed fibers or 
remove damaged tape. Moreover, the backing paper is left sufficiently 
intact to continue to perform its function of transporting the tape and, 
therefore, there is no need to shut down the machine to repair damaged 
portions of the backing paper. The machine operator has no unnecessary 
idle time, and the machine can be used to maximum efficiency to accomplish 
a maximum amount of tape laying without unnecessary interruptions. The 
overall cost of the operation is decreased because of lower personnel 
costs, more efficient use of the expensive machinery, and minimal wastage 
of the composite tape. The cost of the machine itself is also decreased 
since apparatus constructed according to the invention does not require a 
large machined anvil surface or a nearly perfect parallel cutter guide, 
which are extremely costly to produce. In addition, the quality of the 
finished composite structure is maximized and is not impaired by 
relatively imprecise hand cutting. 
These and other advantages and features will become apparent from the 
detailed description of the best mode for carrying out the invention that 
follows.

BEST MODE FOR CARRYING OUT THE INVENTION 
The drawings show a tape laying machine 2 in which the cutting apparatus 10 
is constructed according to the invention and also constitutes the best 
mode of the invention currently known to the applicant. The illustrated 
machine 1 is of the type designed to lay tape on flat surfaces, as shown 
in FIG. 1. When a machine of this type is used in the manufacture of 
contoured aircraft structures, a flat surface is first produced by the 
tape laying operation and then is heat treated to cure it into the desired 
shape. The machine 1 is only one example of a type of machine into which 
the present invention may be incorporated to advantage. Another example is 
the type of tape laying machine that lays tape directly onto a contoured 
surface. 
FIG. 1 is a simplified side elevational view of the machine 2 showing a 
number of conventional features. These conventional features include the 
supply reel 4, the take up reel 6, and the tape laying head 8. As in 
conventional tape laying machines, the tape 100 and backing paper 102 move 
from supply reel 4 down through the cutting apparatus 10 to the tape 
laying head 8. In general, the action of the tape laying head against the 
tape and paper 100, 102 is sufficient to pull the tape and paper 100, 102 
from the supply reel 4. The axial shaft of the take up reel 6 is driven to 
rotate the reel 6 to insure that the paper 102 remains taut and moves 
smoothly from the downstream side of the head 8 to the reel 6. These 
features are conventional and are described herein to illustrate an 
environment in which the method and apparatus of the present invention may 
be used to advantage. It is of course to be understood that such 
conventional features may take various forms and may be changed, omitted, 
or added to without affecting the spirit and scope of the present 
invention. 
FIGS. 2 and 3 show the preferred embodiment of the cutting apparatus 10 of 
the invention. FIG. 2 shows a lateral cut of a very small angle, in the 
order of about 4 degrees, being made. FIG. 3 shows a lateral cut of 
approximately 90 degrees being made. Lateral cuts of both of the 
illustrated orders of magnitude, as well as lateral cuts intermediate 
between the illustrated cuts, can be made completely, efficiently, and 
accurately with apparatus constructed according to the present invention. 
It should be noted that throughout the description of the structure and 
operation of the preferred embodiment of this invention, the term 
"lateral" is intended to include any cut that extends from one side of the 
tape to the other regardless of the angle between the longitudinal axis of 
the tape and the cut. 
The cutting apparatus 10 illustrated in the drawings utilizes a rotary 
cutter blade 12 for cutting the tape 100. It is of course to be understood 
that the method and apparatus of the present invention can be used to 
advantage with other known types of laterally-moving cutting blades in 
tape laying machines. However, a rotary cutting blade such as the blade 12 
shown in the drawings is preferred because the overall efficiency of the 
machine and quality of the cut are greatest when a rotary cutter is used. 
A rotary blade is preferable over a non-rotating blade that is pulled 
across the tape because the latter has a tendency to pull the tape out of 
the tape guide and also a tendency to pull fibers of the tape loose from 
the backing paper. In addition, such blades, when made from presently 
known materials, become dull much faster then a rotary blade because they 
have a single cutting point as opposed to the full circumference of 
cutting points in a rotary blade. Therefore, the method and apparatus of 
the present invention can be used to best advantage in a tape laying 
machine that utilizes a rotary cutter blade. 
The drawings show the preferred embodiment of the controlled depth cutting 
apparatus of the invention. The apparatus includes the rotary cutter blade 
12 and a drive motor 14 for the blade 12. The cutter may be driven by an 
electric motor or an air powered motor. The electric motor is generally 
preferred since air powered motors have a tendency to contaminate the 
atmosphere with particles of oil. Such contamination of the atmosphere is 
highly undesirable in an environment in which composite structures are 
being manufactured. Referring to FIGS. 2-4, a solenoid 16 is provided for 
moving the cutter blade 12 toward the tape 100 and into its cutting 
position. A spring 18 moves the blade 12 back out of its cutting position 
when the solenoid 16 is not actuated. 
An anvil 20 supports the tape 100 and backing paper 102 as the tape is 
being cut. In conventional tape laying machines, the anvil associated with 
the cutter is stationary. The anvil 20 shown in the drawings, in 
accordance with the present invention, moves laterally with respect to the 
tape as the cut is being made. As shown in FIGS. 2-4 both the cutter 12 
and the anvil 20 are mounted on a C-shaped frame 34. This frame 34 moves 
laterally to laterally move the cutter 12 and anvil 20. The simultaneous 
movement of the cutter 12 and anvil 20 allows a single support point on 
the anvil 20 to remain beneath the cutting point of the blade 12 
throughout the entire length of the lateral cut. Therefore, the distance 
between the blade 12 and anvil 20 remains constant and the depth of the 
cut is kept constant to a highly accurate degree. 
The C-shaped frame 34 is a rigid structure that has an outer arm 36 and an 
inner arm 38. The rotary cutter 12 is mounted on the outer arm 36, and the 
anvil 20 is mounted on the inner arm 38. The rigidity of the C-shaped 
frame 34 insures that the movement of the cutter 12 and anvil 20 will be 
simultaneous and that the distance between the cutter 12 and anvil 20 will 
remain constant throughout the entire length of the lateral cut. Any 
variation in the motion of the C-shaped frame will equally affect the 
cutter 12 and the anvil 20. The lateral movement of the C-shaped frame 34 
is provided by a screw drive 32, as shown in FIGS. 2-4. Of course various 
other types of drive means could be used to laterally move the C-shaped 
frame 34 without departing from the spirit and scope of the present 
invention. However, the screw drive 32 is preferred because of its 
strength, durability, and high degree of accuracy and adjustability. The 
screw drive 32 preferably is of the ball screw type to maximize the 
smoothness of the operation. 
The size and shape of the anvil may be varied considerably without 
departing from the spirit and scope of the present invention. However, the 
drawings show the preferred embodiment of the anvil 20. The anvil 20 shown 
in the drawings is relatively small and the surface 21 that faces the 
cutter 12 is crowned or rounded. Only a very small area of contact between 
the anvil and the backing paper 102 is necessary to provide the required 
support for the tape 100 and paper 102 to carry out the cutting operation 
of the tape 100. The crowning of the anvil 20 allows the anvil 20 to slide 
easily under the paper 102. There is less drag than there would be if the 
area of contact were larger and the rounded surface 21 has no edges that 
are likely to catch on the paper 102. Another advantage of the crowned 
shape of the anvil 20 is that the highest point is in the center directly 
under the cutting point of the cutting blade 12. This insures that there 
are no points on the surface 21 of the anvil 20 that are higher than the 
contact point and that could therefore interfere with the supporting 
function of the anvil 20. 
The cutting method and apparatus of the present invention are used to best 
advantage in tape laying machines that also incorporate a tape guide 
constructed in accordance with another invention by the applicant that is 
the subject of a copending application of the applicant entitled Cutting 
Method And Apparatus For Tape Laying Machines, which application was filed 
concurrently with the present application. The tape guide 22 shown in the 
drawings is constructed in accordance with the preferred embodiment of the 
invention disclosed in that copending application. The guide 22 has two 
longitudinal sections that are spaced apart longitudinally to define a gap 
30 therebetween. This gap 30 provides an opening to accommodate the moving 
C-shaped frame 34 and anvil 20. The crowned surface 21 of the anvil 20 is 
positioned to extend a very small amount out of the gap 30 toward the 
cutter 12. This insures that the support point on crowned surface 21 is 
the highest point along the path of the tape 100 through the cutting 
apparatus 10 so that the tape 100 will progress smoothly and will be 
adequately supported by the anvil 20 for the cutting operation. 
The tape 100 and backing paper 102 move along the tape guide 22 as they 
progress from the supply reel 4 to the tape laying head 8. The movement of 
the tape through the tape laying machine is indicated by the arrows in 
FIG. 1. The tape guide 22 guides the tape 100 and paper 102 into position 
for the tape 100 to be cut by the rotary cutter blade 12. Each of the two 
longitudinal sections of the tape guide 22 has an essentially flat center 
portion 24 extending along its length. Each longitudinal section also has 
two opposite sidewalls 26. Between each sidewall 26 and its associated 
flat center portion 24 is a side portion 28 that is inclined toward the 
cutting blade 12 relative to the flat center portion 24. These opposite 
side portions 28 of the tape guide 22 may be either angled or curved 
toward the cutting blade 12. However, in the preferred embodiment the side 
portions 28 are curved since it is easier to manufacture curved as opposed 
to angled side portions and since curved side portions result in smaller 
nicks in the lateral edges of the backing paper 102 produced during the 
cutting operation. The construction of the tape guide 22 is a part of the 
invention disclosed in the copending application discussed above and is in 
no way a part of the present invention. However, the two inventions are 
preferably used together in order to achieve maximum accuracy and 
completeness in the cutting operation. 
During the operation of the tape laying machine 2, the tape 100 and backing 
paper 102 are moved along the tape guide 22 onto the anvil 20 and into 
position for the tape 100 to be cut by the blade 12. As the tape 100 and 
paper 102 are being moved, the tape guide 22 maintains the transverse 
center portions of the tape 100 and paper 102 in an essentially flat 
position. The side portions 28 of the tape guide 22 guide the lateral edge 
portions of the tape 100 and paper 102 to bend toward the cutting blade 12 
and away from the anvil 20. This bending of the lateral edge portions is 
maintained along both longitudinal sections of the tape guide 22 and 
across the gap 30 in which the anvil 20 is positioned. The support and 
guiding of the lateral edge portions on either side of the gap 30 into the 
bent or bowed position maintains the bending of the lateral edge portions 
toward the cutter blade 12 across the gap 30 when a lateral cut is being 
made. This allows a lateral cut of essentially constant depth to 
completely sever the tape 100, including any fibers that may have become 
loose from the edges of the backing paper 102, without severing the 
backing paper 102. The tape guide 22 is dimensioned so that the flat 
center portions 24 are sufficiently wide to provide an uncut center 
portion of the backing paper 102 that is sufficiently wide to prevent any 
nicks in the lateral edge portions of the backing paper 102 from impairing 
the transport of the tape 100 by the backing paper 102. 
The extremely accurate depth control of the present invention provides a 
lateral cut of essentially constant depth. This insures that the tape 100 
is completely severed down to the last fiber. Before beginning the cutting 
operation, the depth of the cut is set by setting the distance between the 
cutter 12 and the anvil 20. As shown in the drawings, this is accomplished 
by rotating adjustable stop 40 which is threaded onto the top of shaft 42 
which is in turn connected to cutter 12. Rotating stop 40 moves cutter 12 
toward or away from anvil 20. Of course, the distance between cutter 12 
and anvil 20 could be set by any of a variety of other means without 
departing from the spirit and scope of the invention. Such other means 
would include means for moving anvil 20 rather than cutter 12. 
Once the distance between the support point on the anvil 20 and the cutting 
point of the cutter 12 is set, it remains constant throughout the cutting 
operation. The distance is set to be slightly less than the thickness of 
the backing paper 102. This insures that all of the fibers of the tape 100 
will be severed without severing the paper 102. The details of the cutting 
operation of the flat center portion of the tape 100 are perhaps best 
shown in FIGS. 5 and 6. In these figures it can be clearly seen that the 
tape 100 is being completely severed and that the paper 102 is merely 
being grazed by the laterally-moving rotary cutter blade 12. The grazing 
of the cutting paper 102 is minor and does not interfere with its tape 
transport function. In FIG. 5, the approximate magnitudes of the 
thicknesses of the tape 100, the paper 102, and the cut are indicated in 
thousandths of an inch. In order to prevent any variations in the radius 
of the cutter 12 from creating variations in the depth of the cut, the 
cutter 12 is precisely machined and is driven to rotate at a very fast 
rate to maximize the circumferential extent of the contact between the 
cutter 12 and each portion of the tape 100. 
In this description of the preferred embodiment of the invention, the 
phrase "cut of essentially constant depth" and the like are intended to 
mean a cut that leaves an uncut layer of material (backing paper) of 
essentially constant thickness. To leave such a layer, the cut would 
generally be of essentially constant depth, but of course variations in 
paper thickness and/or thickness of the tape layer would cause 
corresponding variations in the actual depth of the cut. The distance 
between the cutter 12 and anvil 20 is set to be very slightly less than 
the thickness of the paper 102 at its thinnest point. 
Throughout the description of the preferred embodiment of the method and 
apparatus of the present invention, the invention has been described in 
the context of a tape laying machine. It is anticipated that this 
environment will be the primary use for the method and apparatus of the 
invention. However, it is to be understood that the method and apparatus 
of the invention may also be used to advantage in other environments in 
which it is necessary to attain a high degree of accuracy of depth control 
in a cutting operation. 
It will be obvious to those skilled in the art to which this invention is 
addressed that the invention may be used to advantage in a variety of 
situations. Therefore, it is also to be understood by those skilled in the 
art that various changes, modifications, and omissions in form and detail 
may be made without departing from the spirit and scope of the present 
invention as defined by the following claims.