Apparatus for constant pressure diagonal-web crush-scoring

There is provided an apparatus for applying constant pressure to a plurality of anvil rollers for crush-scoring used in combination with crush-scoring cylinders having protrusions extending from the surface thereof. Each anvil roller is supported in a substantially frictionless manner and the constant pressure is supplied by a flexible diaphragm acting on a plunger which can move substantially without friction in a pneumatic cylinder.

FIELD OF THE INVENTION 
The present invention is directed to an apparatus for applying constant 
pressure in mechanical diagonal-web crush-scoring and, more particularly, 
to an apparatus for diagonal crush-scoring a web to be used as the release 
liner or backing for labels, stickers, tapes, or similar articles bearing 
a pressure-sensitive adhesive. 
BACKGROUND OF THE INVENTION 
Adhesive products such as labels, stickers, tapes, and similar articles, 
are normally comprised of a surface sheet or facestock, a layer of 
adhesive, normally pressure-sensitive, secured to the back face of such 
surface sheet, and a removable paper backing sheet or release liner 
secured to the adhesive layer by a low surface-energy bond, such as a 
silicon coating, for ultimate removal when the label, sticker, or the 
like, is to be affixed to an article or substrate for end-use purposes. 
The backing sheet can be difficult to remove because no edge is usually 
exposed to facilitate grasping the backing sheet for its removal. 
One approach to overcoming the difficulties encountered in removing backing 
sheets, is to crush-score the backing sheet before it is secured to the 
layer of adhesive and before it is silicone-release-coated. Crush-scoring 
leaves a line in the backing sheet that has been weakened by a compaction 
of the fibres in the sheet. When a label, sticker or the like is to be 
affixed, it can be flexed to cause the backing sheet to split or tear 
along the score line, creating a pair of exposed edges for grasping the 
backing sheet. The final dimensions of the labels, stickers or the like to 
be produced, often makes it advantageous to arrange the score lines in a 
diagonal pattern on the backing sheet, to maximize the length of score 
line available on the back of the product for creating exposed edges. 
The amount of weakening that takes place during crush-scoring, however, 
must be carefully controlled to prevent splitting or tearing of the 
backing sheet while it is being processed or prepared for use, and to 
avoid producing labels, stickers or the like where splitting or tearing 
prematurely occurs or does not occur upon flexing. 
Forming diagonal scores across a web of paper for release-liner use has 
been determined, with proper spacing of scores, to enable labels of any 
size to be cut from the web, with high statistical assurance that it will 
contain at least one edge-to-edge score to insure a crack-and-peel 
feature, i.e., the ability to form a crack at any score line and peel the 
backing across any other score line present. 
The present invention is directed to a system for uniform diagonal 
crush-scoring at a constant and controllable pressure, to achieve a 
product of the highest quality. 
SUMMARY OF THE INVENTION 
According to the present invention, there is provided apparatus for 
crush-scoring paper, particularly paper used as the release liner in label 
construction, in which a floating force for scoring is maintained 
substantially constant and unbiased, and is applied to the surface 
undergoing crush-scoring, under essentially friction-free conditions. 
The heart of the system is a support providing a pair of guide rods, 
preferably cylindrical rods set in substantially frictionless bearings, 
which extend outwardly from the support means and are coupled to a 
mounting bracket which contains, for present purposes, a cylindrical anvil 
roller, used to crush-score paper. 
Between the circular guides, is a plunger which extends from the mounting 
bracket to a sealed flexible diaphragm, which is in communication with a 
pressurized fluid, preferably gaseous, and which provides the force to be 
transmitted through the rod to the mounting bracket. 
In the preferred assembly, the plunger is not secured to the mounting 
bracket nor the diaphragm, and the cooperation among the mounting bracket, 
the plunger, and the diaphragm, does not involve the use of frictional 
measures and is bond-free. This, coupled with the use of essentially 
frictionless mounts and guides, insures that the mounting bracket will 
float, and that the force applied to the mounting bracket, and therefore 
to the anvil rollers, will be essentially unidirectional and controlled by 
the amount of fluid pressure applied to the diaphragm. 
In the system for crush-scoring paper, a plurality of anvil rollers 
contained on a corresponding plurality of mounting brackets on a plurality 
of adjacent supports, are positioned in staggered, overlapping relation 
along a support rod. Each is readily removable as wear or damage dictates. 
Preferably, the cylindrical anvil rollers are pivotably adjustable to 
insure positioning parallel to the crushing cylinder. Paper is passed 
between the anvil rollers and a wire-wound crushing cylinder. The wires 
are removably embedded in grooves extending diagonally across the surface 
of the cylinder from edge to edge. Preferably, they are spring-tensioned 
to account for thermal expansion and contraction. They are 
precision-ground to insure uniform extension from the surface of the 
cylinder. 
In the process of scoring, paper from a roll is passed between the crushing 
cylinder and a plurality of anvil rollers, with pressure applied against 
each being tailored to achieve the depth of score desired for appropriate 
cracking and peel performance of the paper. Backlighting enables 
inspection of fluctuations in depth of the score, and adjustment of the 
applied pressure accordingly. 
By use of the apparatus of the instant invention, higher-quality scores 
than ever previously achieved, may be realized for uniform performance of 
the products in the hands of the consumer.

DETAILED DESCRIPTION 
The present invention pertains to an apparatus for crush-scoring paper, in 
which a plurality of cylindrical anvil rollers are independently supported 
in a substantially frictionless manner, for selectively applying an 
unbiased constant pressure to diagonal wires of a wire-wound cylinder, to 
enable diagonal crushing of paper at uniform loads across the cylinder. 
The following is a description of a preferred embodiment of the invention 
as shown in the drawings. 
With reference to FIGS. 1, 1A, 2, 2A, and 2B, each anvil roller holder 10 
has cylindrical anvil roller 12 rotatably supported by mounting bracket 
14. Mounting bracket 14 is of unitary construction, preferably one piece 
comprised of end member 16, from which a pair of panel members 18 and 20 
extend outwardly, parallel to one another. A cylindrical pin 22 extends 
between side panels 18 and 20 at a point remote from the back spacer bar 
16. Pin 22 extends through a corresponding hole in the center of anvil 
roller 12. The anvil roller freely rotates about pin 22, preferably by 
means of ball or roller bearings. 
Anvil roller 12 should be as perfectly cylindrical as possible. 
Extending outward from the surface of end member 16, opposite anvil roller 
12, is a pair of smooth guide rods 26 and 28, which are preferably 
cylindrical, as shown. The guides extend, parallel to one another, outward 
from opposite ends of spacer bar 16. The opposed or remote ends of guide 
rods 26 and 28 are joined to one another by connecting brace 30 extending 
between them. 
The cylindrical guides over most of their length, and the connecting brace, 
are enclosed in a support cabinet 32. The underside of cabinet 32 is 
adapted to be attached to mounting pedestal 34 for installation of the 
anvil roller holder at a work site. To accomplish this, the edge of the 
underside of cabinet 32 nearest the anvil roller, has a wedged lip 36 
extending downward, which dovetails with the top of pedestal 34. With 
additional reference to FIG. 1A also extending downward from the underside 
of cabinet 32, remote from lip 36 so that it will be on the opposite side 
of pedestal 34 from lip 36, is a screw mount 38. At the free end of screw 
mount 38, a pair of cylindrical pins 40 extend outward from opposite sides 
of screw mount 38 to hold lockpiece 42 in place by extending through 
elongated apertures 44 on opposite sides of lockpiece 42. Lockpiece 42 is 
U-shaped, with the opposing sides being on either side of the screw mount 
and the bottom member facing the pedestal. Screw 46 extends through the 
screw mount so that it comes in contact with the bottom member of 
lockpiece 42. Lockpiece 42 is tightened against the other slanted surface 
of pedestal 34, by tightening screw 46, to hold the anvil roller holder in 
place. Elongated apertures 44 in the opposing sides of lockpiece 42, 
determine the amount of play available for tightening. 
With reference to FIGS. 1B, 1C and 1D, there is depicted an alternate means 
for attaching the underside of cabinet 32 to mounting pedestal 34 for 
installation of the anvil roller holder at a work site. This alternate 
embodiment is preferred to ensure parallelism between the surface of the 
anvil rollers and the surface on which they will be acting, and is 
particularly preferred if precision parts are not used in the attachment 
means, to save expense. 
In this embodiment, an attachment bracket 100 is positioned between the 
underside of cabinet 32 and the top surface of pedestal 34, by two pairs 
of bolts 102 and 104, and a pin 103. Pin 103 extends upward through 
corresponding cylindrical holes in bracket 100 and the underside of 
cabinet 32, located at the center of the edge nearest the anvil roller. 
Bracket 100 has a wedged lip 106 extending downward at this edge which 
dovetails with the top of pedestal 34. Pin 103 is retained in place by 
lock plate 105 extending across the underside of bracket 100 and covering 
the cylindrical hole for pin 103, which extends through bracket 100 into 
cabinet 32. Plate 105 is in turn held in place by bolts 102 extending up 
through the plate and oversized cylindrical holes in bracket 100 located 
on either side of pin 103 and secured to the underside of cabinet 32. 
Spring washers 108 are positioned on bolts 102 between the underside of 
bracket 100 and plate 105. Nuts 110 can be tightened down from the free 
end of bolts 102, to hold plate 105 in place and to hold this edge of the 
attachment bracket against the underside of cabinet 32. 
Pin 103 provides a pivot point about which cabinet 32 can rotate with 
respect to attachment bracket 100. The oversized cylindrical holes in 
bracket 100 surrounding bolts 102, allow room for the bolts to move in the 
holes when cabinet 32 is pivoted. Spring washers 108 transmit the torque 
from the tightening of nuts 110 to the underside of bracket 100 and create 
the friction which must be overcome in order for cabinet 32 to pivot. This 
friction holds bracket 100 and cabinet 32 together and allows pivoting at 
the same time. The ends of plate 105 may be turned down after nuts 110 are 
tightened into place, to prevent the nuts from loosening. 
Bolts 104 are aligned on the opposite side of pedestal 34 from bolts 102 
and extend upward through oversized cylindrical holes in attachment 
bracket 100 and are secured to the underside of cabinet 32. Washers 112 
and nuts 114 can be tightened down from the free end of bolts 104. 
However, mounted on bolts 104, between the underside of the attachment 
bracket and washers 112 and nuts 114, is an adjustable wedge 116 with an 
el-shaped cross-section. When tightened into place, one end of the el will 
rest against the other slanted surface of pedestal 34, while the other end 
rests against the underside of the attachment bracket. A lip 118, 
extending downward from the underside of the attachment bracket at the 
edge furthest from the anvil rollers, acts to hold adjustable wedge 116 
against the pedestal. 
Bolts 104 extend through adjustable wedge 116 at elongated apertures 120. 
These elongated apertures have a width which fits the diameter of bolts 
104, but a length which allows the bolts to be positioned at various 
distances from the pedestal. In this way the adjustable wedge can adapt to 
the adjustments necessary to establish parallelism. In addition, the 
cylindrical holes in bracket 100 surrounding bolts 104, are oversized to 
allow room for bolts 104 to move when cabinet 32 is pivoted. 
Attached by three bolts 122 to the side surface of the attachment bracket 
facing away from the anvil rollers, is adjustment bracket 124. Bracket 124 
is el-shaped, with one leg of the el having bolts 122 extending through it 
to secure it to bracket 100, and the other leg extending upward adjacent 
one edge of the back surface of cabinet 32. Attachment bracket 100 is 
spaced from the rear surface of cabinet 32, providing a small clearance 
between adjustment bracket 124 and the rear surface of cabinet 32. 
Attached to the back surface of cabinet 32 by a pair of bolts 126, is 
adjustment brace 128. Adjustment brace 128 is positioned along an edge of 
the rear surface of cabinet 32 above the leg of bracket 124, and is 
secured by bolts 122 to cabinet 32 and opposite the other leg of bracket 
124. Extending between the opposed surfaces of bracket 124 and brace 128, 
are backlash coil spring 130 and a differential screw adjustor 132. Screw 
adjustor 132 is differentially threaded into each surface and centrally 
incorporates an integral nut 134 having a hexagonal cross-section to 
provide a one-piece differential screw adjustor that can be turned with a 
wrench. 
Turning the screw adjustor one way or the other, will result in brace 128 
and bracket 124 moving either closer to one another or further from one 
another, thereby pivoting cabinet 32 and changing the position to be 
assumed by the anvil roller when adjustable wedge 116 is tightened against 
bar 34. This allows an operator to adjust the position of the anvil roller 
until it is parallel to the surface to be acted upon. To this end, 
generally one rotation of adjustor 132 can result in a movement of brace 
128 relative to bracket 124 in the order of about one-thousandth of an 
inch. 
Guides 26 and 28 are supported in cabinet 32, only by sets of low-friction 
bearings 48 and 50, preferably linear ball bearings. In the presently 
preferred embodiment, the low-friction bearings are Thompson ball 
bearings, but it should be understood that any bearing providing 
substantially frictionless support, may be used. Bearings 48 and 50 allow 
in-and-out longitudinal movements of the cylindrical guides, into support 
cabinet 32, substantially without friction. 
To provide controlled pressure to anvil roller 12, pneumatic cylinder 52 is 
provided within the cabinet. The central, longitudinal axis of the 
pneumatic cylinder is substantially parallel to guides 26 and 28, and 
intersects the center of bar member 16. The end of the cylinder closest 
anvil roller 12, is capped with cylinder head 54. Plunger 55 is loosely 
and frictionlessly fitted inside cylinder 52, and has a head 58, which 
extends across its cross-section. Rod 56 frictionlessly extends out from 
one surface of head 58 along the central, longitudinal axis of the 
cylinder through cylinder head 54, until it contacts the mounting bracket 
comprising bar member 16. Where the rod passes through cylinder head 54, 
sufficient clearance is provided to make the fit relatively loose. The 
loose fit of the rod and head enables the two to move within the cylinder 
with little, or essentially no, friction, with rods 26 and 28 being relied 
on to insure proper anvil roller positioning. 
On the other side of plunger 55, opposite rod 56, flexible diaphragm 60 
extends across the inside cross-section of the pneumatic cylinder. In the 
end of the cylinder, opposite cylinder head 54, is inlet 62, through which 
a compressed gas, or its equivalent, can be fed to the portion of the 
pneumatic cylinder on the side of the diaphragm opposite the plunger. When 
the compressed gas is fed to the cylinder, it will deflect the diaphragm, 
communicating the gas pressure to the point where the anvil roller 
contacts the material being crush-scored, through the head, rod and 
mounting bracket. The use of the diaphragm allows the plunger to be 
loosely fitted without the friction-creating gaskets that would be 
necessary if the plunger had to have an airtight seal with the wall of the 
cylinder. Gasket 64, between the outer surface of the end wall of the 
cylinder and the cabinet portion supporting the cylinder, prevents 
compressed gas from leaking around the cylinder. 
Compressed gas is fed to inlet 62 through connecting conduit 66, which 
extends out of cabinet 32 to a source of pressure-regulated compressed 
gas. The pathway of conduit 66 through cabinet 32, is shown in FIGS. 1 and 
2B, in combination. Pressure should be available to deliver a force to the 
anvil-roller, at the point of contact, sufficient to enable crush-scoring. 
A force up to about 50 pounds may be used. Because of gas compressibility 
this force remains constant because, even if there are irregularities in 
the diameter of the anvil roller or the thickness of the web being 
crush-scored, the anvil roller will be able to float with the 
irregularities, due to the substantially frictionless support. The use of 
a compressed gas as a pressure source, is preferred over a relatively 
incompressible hydraulic fluid, so that the anvil roller is best able to 
float without a significant pressure change. 
While it is advantageous to minimize the friction present when the anvil 
roller moves, it is also desirable to provide a zero point for the anvil 
roller, to prevent it from coming into premature or undesired contact with 
the wires of wire-round crushing cylinder 68, used to support the web to 
be crush-scored, opposite the anvil rollers. Such contact could damage the 
wires of the crushing cylinder and/or the anvil rollers. A zero point is 
provided by screw-adjusted wedge 70. Screw-adjusted wedge 70 has a slanted 
or inclined surface which presses against set pin 72, extending outward 
from the surface of connecting brace 30. In combination with adjustment of 
differential screw 74, the slanted surface of wedge 70 can be moved across 
set pin 72, to arrive at a zero point from which anvil roller 12 extends 
to diaphragm 60, on application of pressure. The zero point is determined 
by turning differential screw 74, which in turn induces travel to the 
wedge, which is threaded to the screw and is driven thereby. As indicated, 
changing the position of the wedge, changes on its slanted surface the 
point at which set pin 72 will contact. Differential screw 74 extends out 
of cabinet 32 for easy access. A segment of guide 26 has a narrower 
diameter to allow room for conduit 66 and screw 74. FIG. 2B shows the 
zero-point-adjustment feature as seen from above. 
FIGS. 1 and 2 also show the cooperation between anvil roller holder 10 and 
wire-wound crushing cylinder 68 with a paper backing sheet 96 being 
crush-scored. The wire-wound crushing cylinder is cylindrical, and freely 
rotates about the axis determined by precision bearings 78. A single 
cylinder is normally used in conjunction with a number of anvil rollers, 
positioned in a staggered line by their holders, side by side and in 
overlapping roller arrangement. 
Adjacent anvil rollers are alternately positioned above and below one 
another, so that the paths they roll out on the paper to be crush-scored, 
can overlap. It is presently preferred that the extent of this overlap be 
from about 0.005 to 0.01 inch. While the adjacent anvil rollers are 
staggered to allow overlap, they are preferably positioned relatively 
close to one another so that the force transmitted from rod 56 is 
transmitted to the material to be crush-scored, in as straight a line as 
possible. By staggering the anvil rollers as little as possible, so long 
as they do not interfere with one another, each anvil roller can be 
positioned as close as possible to intersecting the longitudinal axis of 
rod 56. 
With reference to FIGS. 2 and 2A, the crushing cylinder is diagonally wound 
with a set of smooth cylindrical wires 88. The wires should be as 
perfectly round as possible, and their surfaces should be as smooth as 
possible. In addition, the diameter of the wires should remain constant 
throughout their length. The presently preferred diameter for the wires is 
from about 0.02 to about 0.04 inch. 
Wires 88 are held taut on the crushing cylinder by screw clamps 90. Each 
end of a wire is held by a pair of corresponding clamps 90, attached to 
opposite ends of crushing cylinder 68. Each clamp is screw-adjustable, as 
shown in FIG. 2A, so that the wires can be held taut. A locking screw 92 
meets each clamp at right angles to lock the clamp in position once a wire 
has been tightened. In addition, a spring 94 is provided for each clamp, 
with one end being connected to the end surface of the crushing cylinder 
adjacent the clamp on the side opposite the edge of the crushing cylinder, 
and the other end being looped over the end of a wire just before it is 
connected to the spring's corresponding clamp. Springs 94 provide a spring 
loading to the ends of the wires, helping to keep them taut, and 
compensating for expansion of the wires when the ambient temperature 
changes. 
The wires are held in place on the surface of crushing cylinder 68 by 
rounded grooves extending diagonally along its surface. The grooves 
preferably have a depth slightly greater than the radius of wires 88. The 
grooves may be arranged along the surface of crushing cylinder 68 at any 
pattern including, but not limited to, the depicted 45-degree angle with 
respect to its longitudinal axis, as shown in FIG. 2. The grooves are 
spaced with respect to one another in any desired pattern as depicted in 
FIG. 1. Depicted from an axial cross-section, a prospective groove is 
positioned every 15 degrees about the surface of the crushing cylinder. 
Although the paths of adjacent anvil rollers overlap, the length of the 
anvil rollers are dimensioned, with respect to the distance between wires 
88, so that only one anvil roller is acting against a single strand of 
wire, underneath the web to be crush-scored at any given time. This mode 
of operation is preferred so the load from one anvil roller is transferred 
to a single wire to maintain a constant pressure. 
In this embodiment, a roller is prevented from acting on two wires at once. 
In consequence, an irregularity in one of the wires, such as increased 
diameter, will not result in reduced pressure on the adjacent wire and a 
score mark that is too shallow. 
Nonetheless, FIG. 5 shows an alternate functional embodiment of the present 
invention. In this embodiment, a single small dowel 98 acts at one time, 
against the full length of the crushing cylinder and all the wires. Dowel 
98 is held in place by a number of adjacent anvil roller holders. Mounting 
bracket 14 is arranged to hold two anvil rollers 12 one on top of the 
other. Anvil rollers 12 combine to hold dowel 98 in place against the 
crushing cylinder. As indicated, this embodiment is not as preferred as 
that wherein an anvil roller acts on a single strand of wire at a time, 
but it is preferred over having one long anvil roller act on all the 
wires, because the dowel has some give to it so that it can react to 
irregularities in individual wires, and the dual anvil rollers provide 
individual sources of force that can react individually to such 
irregularities. Dowel 98 should be flexible enough to transfer the load 
from anvil rollers to all wires on the roll. 
With reference to FIG. 3, paper stock for release liner 76, has been 
secured to adhesive layer 82, which in turn is secured to surface sheet 
84. A score mark 86 is shown in side view. If the thickness of backing 
sheet 76 is from about 0.003 to about 0.008 inch, this amount of 
compaction allows the backing sheet to split or tear when flexed, as shown 
in FIG. 4, but is sufficiently sturdy to withstand peel-across at score 
lines. 
The principal objective in the use of the apparatus of the instant 
invention, is to keep it operative under essentially frictionless 
conditions with only a unilateral force being applied through the fluid 
pressure against the diaphragm, such that the anvil rollers will float 
with fluctuations in paper thickness. The use of gaseous pressure is 
preferred, as compressibility of the gas allows for movement of the anvil 
rollers to and from cabinet 32 without any significant changes in applied 
pressure. However, to minimize any fluctuations, the diameters of the 
anvil roller, the crushing cylinder, and the wire, are controlled to as 
close a tolerance as possible. While cylindrical guide rods are currently 
used, they may be of any cross-sectional configuration, so long as there 
are available for them, bearings to enable essentially frictionless 
movement in and out of cabinet 32. 
Similarly, since rod 56 may also be of any cross-sectional configuration, 
as it is essentially mounted in cooperation with head 58 and diaphragm 60 
in a frictionless manner. With reference to FIGS. 1 and 2, the web of 
material (paper) to be scored 96 is passed between anvil roller 12 and the 
wires 88 of crushing cylinder 68. Any number of anvil roller assemblies 
may be mounted on support 34 in a parallel array. The amount of pressure 
applied to diaphragm 60 of each assembly, determines the compressive force 
to be applied to crush-score paper 96. With the aid of backlighting, an 
operator can view from above, the direction of paper travel, and can 
ascertain if the depth of the diagonal score is uniform, If not, the 
operator, by adjusting the pressure associated with any given anvil 
roller, can insure that the diagonal crush-score will be uniform 
throughout the width of the web. This insures, when the paper is coated 
with a release material such as a silicone release coating after scoring 
and then laminated to an adhesive and a facestock, that there will be at 
all times, uniform performance in the crack-and-peel operation of the 
construction. 
To this end, it is desired that the paper be scored before applying a 
low-energy release surface on the opposed side thereof, for, if earlier 
applied, the pressure applied during the scoring operation could crack the 
release coating and provide a product of inferior quality. 
The preceding description has been presented with reference to a presently 
preferred embodiment of the invention shown in the accompanying drawings. 
Workers skilled in the art and technology to which this invention 
pertains, will appreciate that alterations and changes in the described 
apparatus and structure can be practiced without meaningfully departing 
from the principles, spirit and scope of this invention. Accordingly, the 
foregoing description should not be read as pertaining only to the precise 
structures and techniques described, but rather should be read consistent 
with, and as support for, the following claims which are to have their 
fullest fair scope.