U.S. patent number 3,825,162 [Application Number 05/333,816] was granted by the patent office on 1974-07-23 for feed mechanism.
Invention is credited to Leo J. Hubbard.
United States Patent |
3,825,162 |
Hubbard |
July 23, 1974 |
FEED MECHANISM
Abstract
Mechanisms for feeding documents having perforations along their
marginal edges are described. These mechanisms have frames which
define linear paths for endless belts made of spring material along
the drive path of the document perforations. The frames support the
belts for curvilinear motion around and away from the ends of the
linear paths. The belts have unitary pin and roller drive elements
which extend through perforations in the belt at equidistant
intervals therealong. Sprockets supported by the frame and
journalled therein carry the belt around the curvilinear paths. The
drive elements and the belts can be molded together into a unitary
structure.
Inventors: |
Hubbard; Leo J. (Somerset,
MA) |
Family
ID: |
23304373 |
Appl.
No.: |
05/333,816 |
Filed: |
February 20, 1973 |
Current U.S.
Class: |
226/74 |
Current CPC
Class: |
B41J
11/30 (20130101); B65H 20/20 (20130101) |
Current International
Class: |
B41J
11/26 (20060101); B41J 11/30 (20060101); B65H
20/20 (20060101); G03b 001/30 () |
Field of
Search: |
;226/74,75 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
649,199 |
|
Jan 1951 |
|
GB |
|
1,229,552 |
|
Dec 1966 |
|
DT |
|
Primary Examiner: Knowles; Allen N.
Attorney, Agent or Firm: Lukacher; Martin
Claims
What is claimed is:
1. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
drive elements projecting transversely from the feeding surface of
said belt,
a frame supporting said belt along the surface thereof opposite to
said feeding surface,
driving means engaged with said belt,
said drive elements having a pin portion which projects through
said feeding surface, said pin portion having a cylindrical base
and a hemispherical cap on said base and a drive means engagement
portion which projects through said opposite surface of said strip,
said drive means engagement portion being a hemicylinder having its
axis perpendicular to said pin portion, and its base in
juxtaposition with said opposite surface, said pin having a
hemispherical cap, the surface of said cap and said hemi-cylinder
lying along a common circle,
said strip being perforated at positions longitudinally spaced from
each other, and said drive elements being disposed in said
perforations.
2. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
a frame supporting said belt along the surface thereof opposite to
said feeding surface, driving means engaged with said belt,
drive elements projecting transversely from the feeding surface of
said belt, said drive elements having a pin portion which projects
through said feeding surface, said pin portion having a cylindrical
base and a hemispherical cap on said base, and a drive means
engagement portion which projects through said opposite surface of
said strip, said strip being formed into an endless belt, said
strip being perforated at positions longitudinally spaced from each
other, said drive elements are disposed in said perforations,
and
said perforations each having a tab projecting therefrom into
interlocking relationship with said drive elements therein.
3. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
a frame supporting said belt along the surface thereof opposite to
said feeding surface,
driving means engaged with said belt,
drive elements projecting transversely from the feeding surface of
said belt, said drive elements having a pin portion which projects
through said feeding surface, said pin portion having a cylindrical
base and a hemispherical cap on said base, and a drive means
engagement portion which projects through said opposite surface of
said strip, said drive means engaging element having a larger
diameter than said pin portion as measured respectively at the
opposite and feeding surfaces of said strip,
said strip being perforated at positions longitudinally spaced from
each other, said drive elements being disposed in said
perforations, and
said pin portion having a circumferential lip which tapers
outwardly in the direction opposite from the cap thereof to define
a slot between the bottom of said lip and the top of said drive
means engaging portion for receiving one of said perforations in
said strip when said drive element is snap fitted therein.
4. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
drive elements projecting transversely from the feeding surface of
said belt, said drive elements having a pin portion which projects
through said feeding surface, said pin portion having a cylindrical
base and a hemispherical cap on said base;
a frame supporting said belt along the surface thereof opposite to
said feeding surface, and
driving means engaged with said belt,
a drive means engagement portion which projects through said
opposite surface of said strip;
said perforations being selected from square and non-symmetric
shapes,
said strip being perforated at positions longitudinally spaced from
each other and said drive elements are disposed in said
perforations.
5. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
drive elements projecting transversely from the feeding surface of
said belt,
a frame supporting said belt along the surface thereof opposite to
said feeding surface,
said frame includes a pair of side plates disposed along opposite
edges of said belt, each of said plates having a shoulder extending
along the path of said belt, each shoulder extending under said
surface of said belt opposite to said feeding surface thereof;
said plates each have guide surfaces above said shoulders, said
guide surfaces extending linearly between the ends of said plates,
said guide surfaces being coplanar with said feeding surface of
said belt, said shoulders and said guide surfaces having a wall
therebetween, said wall and said shoulders providing a guide for
said belt along a linear path coplanar with said guide surfaces
and,
driving means engaged with said belt.
6. The invention as set forth in claim 5 wherein said drive
elements include pin portions and hemi-cylindrical lugs, which are
spaced in equi-distance from each other along a predetermined
circular path, said drive means comprising a pair of sprockets
journalled in said frame between the plates thereof, said sprockets
having peripheries which define said circular path, said sprockets
also having hemi-cylindrical slots therein spaced along said path
by distances equal to the spacing of said lugs.
7. The invention as set forth in claim 6 wherein said feed
mechanism includes a pair of the mechanisms as defined in claim 5,
a drive shaft and a guide shaft, disposed in parallel relationship,
said drive shaft extending into and in driving relationship with a
first sprocket on each of said mechanisms, and said guide shaft
extending into the second of said sprockets of each of said
mechanisms, said mechanisms being spaced laterally from each other
along said shafts.
8. The invention as set forth in claim 7 wherein a perforated web
is disposed on said guide surfaces of said mechanisms with the
perforations therein in engagement with the pins projecting from
the belts of said mechanisms, each of said mechanisms having a
slotted guide plate pivotally mounted on the frames thereof, said
guide plates being pivotable onto guide surfaces thereof to hold
down said web on said guide surfaces with said pin portions
projecting through said slots in said guide plates.
9. A feed mechanism which comprises:
a strip of flexible material having its thinnest dimension between
a feeding surface and a surface closely adjacent thereto,
said strip being formed into an endless belt,
drive elements projecting transversely from the feeding surface of
said belt,
said strip being perforated at positions longitudinally spaced from
each other and said drive elements are disposed in said
perforations;
said drive elements having a pin portion which projects through
said feeding surface, said pin portion having a cylindrical base
and a hemispherical cap on said base; and
a drive means engagement portion which projects through said
opposite surface of said strip;
a frame supporting said belt along the surface thereof opposite to
said feeding surface, and
driving means engaged with said belt, and
said pin and drive means engaging portion being integral with each
other and formed by molding on to said strip,
said belt and said drive elements being of dissimilar materials
made into an integral assembly by placing said belt in a mold and
injecting said drive element materials into said mold and through
said belt perforations.
Description
The present invention relates to mechanisms for feeding, advancing
or positioning movable members and particularly to mechanisms for
feeding perforated webs.
The invention is especially suitable for use in feeding of
edge-perforated documents as are generally used in computer
peripheral equipment, such as printers, teletypewriters and optical
character readers. Features of the invention are however generally
applicable for feeding any movable members, such as work tables
used on machine tools, particularly numerically controlled machine
tools, tapes and other record media.
Feeding of certain driven members, particularly computer forms
requires a feed mechanism capable of moving at extremely high
speeds and of undergoing rapid acceleration and deceleration. Any
skew or meandering of the drive causes misalignment of the forms or
members with operating devices, such as printer heads. If the feed
mechanism is not fast acting, misregistration can readily occur. In
the case of perforated documents which are fed through pin drive
elements, skewing and improper entrance and stripping of the pin
tends to tear the document, jam the document in the mechanism and
cause costly down time of the entire computer system. These
requirements for high speed rapid acceleration and deceleration,
close tolerances on skewing, entry and exit of the pins, and
accuracy of movement with respect to the operating member, such as
the printer head, are not compatible with each other and have
resulted in the use of complex and costly feed mechanisms.
Characteristic of these feed mechanisms is the so called "tractor"
which employs a chain, much like a bicycle chain, which is carried
by a pair of sprocket gears, each link of the chain carries a
sprocket pin which extends from an outboard bracket or beam
cantilevered from the chain. The pins enter the perforations in the
document as they pass from curved paths around the sprockets into a
straight path and are stripped from the documents as they leave the
curved path when drawn around a second sprocket. Close tolerances
are required between the pin location and the sprockets or else
pairs of these tractors along opposite marginal edges of the
document will not be in synchronism and will cause the entire
document to skew, drag, bind, or actually tear in the mechanism.
Thus, complex phasing adjustments at the sprocket shafts are
required and must be maintained by regular adjustments during
operation. Such adjustments are oftentimes incompatible with clean
entry and stripping of the pins which cause driving forces to be
applied to the document perforations in other than the linear path,
thus tearing and damaging the document. The chain, bracket and
sprocket drives also are heavy, have high inertia, and are not
compatible with high speed and rapid acceleration and deceleration
of the driven member.
Other attempts at feed mechanisms have included timing belts,
pulley drives, pressure rollers, and capstan arrangements, all of
which are generally very complex and have high cost of manufacture.
Also, timing belts suffer from stretch and skew effects and do not
maintain necessary intimate contact with the driven member. Also,
frequent adjustments, belt replacements, and binding with documents
being fed, have militated against the acceptance of such mechanisms
in operational equipment.
It is an object of the present invention to provide improved feed
mechanisms wherein the foregoing difficulties and disadvantages are
substantially eliminated.
It is a further object of the present invention to provide feed
mechanisms having moving elements with extremely low mass which are
adapted to rapidly accelerate and decelerate a driven member, such
as an edge-perforated document, and which is also adaptable to
drive such a driven member at high speed.
It is a still further object of the present invention to provide a
feed mechanism which is easily positioned with great accuracy with
respect to a driven member and maintain such position without
requiring continual adjustment.
It is a still further object of the present invention to provide a
feed mechanism especially adapted for feeding webs such as computer
forms, which is easy to clean and maintain.
It is a still further object of the present invention to provide a
feed mechanism having low noise and vibration characteristics.
It is a still further object of the present invention to provide
feed mechanisms which are especially adapted for feeding computer
forms which are uncomplicated and which may be readily manufactured
at low cost.
Briefly described, a feed mechanism embodying the invention
utilizes a strip of flexible material, such as stainless spring
steel and the materials to be mentioned hereinafter which are
extremely stable dimensionally and yet are extremely light in
weight and have low inertia. The strip material is characterized as
having flexibility without being subject to fatigue failure. The
following properties of the material contribute to this
characteristic: low modulus of elasticity; high tensile strength;
high folding endurance; and high impact strength. Strips of the
following materials have, in accordance with the invention been
found to possess these characteristics: Stainless steel; titanium,
polyester film (sold under the Trademark Mylar by E. I. Dupont
& Co., Wilmington, Del.) and polymide film (sold under the
Trademark Kapton, also by Dupont).
The strip is formed into an endless belt and presents a feeding
surface facing outwardly and a surface opposite to the feeding
surface which faces the area enclosed by the belt. Drive elements
project from the feeding surface of the belt and may be in the form
of pins which are spaced equidistant from each other; the
increments between the pins being equal to the increments between
the perforations of the document which is adapted to be driven by
the mechanism. The drive elements may also have portions which
project from the opposite or inner surface of the belt and which
may be integral with the portions of the element which project from
the feeding surface thereof. A frame supports the belt along the
opposite or inner surface thereof and provides a bed along a linear
path which may be disposed adjacent to the document to be fed.
Driving means which may be disposed in the frame are provided for
driving the belt. These driving means may be sprockets, at least
one of which is a drive sprocket, while the other is an idler
sprocket. The sprockets may be formed with hemi-cylindrical slots
which engage the portions of the drive elements projecting from the
opposite surface of the belt. These portions may be
hemi-cylindrical and function as rollers in that as the sprockets
turn, the drive elements roll with respect to the hemi-cylindrical
slots in the sprockets thus providing accurate, low friction drive
for the belt. The entire assembly thus provides accurate guidance
of the belt, extremely low mass with respect to its moving
elements, and accurate entry and removal of the driving elements
from the driven member, such as the computer form, at the
perforations therein.
The belt and pins can be molded together to provide an integral
structure. The capability for such a structure is provided by the
aforementioned materials which have a high melting point or
combustion temperature.
The foregoing and other objects and advantages of the present
invention will become more readily apparent from a reading of the
following description in connection with the accompanying drawings
in which:
FIG. 1 is a perspective view of a sleeve mechanism for continuous
computer forms which embodies the present invention;
FIG. 2 is an enlarged perspective view of a feed mechanism provided
in accordance with the invention which is typical of the mechanism
shown in FIG. 1;
FIG. 3 is a front sectional view of the mechanism shown in FIG. 2,
the section being taken generally along the line 3--3 in FIG.
2;
FIG. 4 is a sectional view of the mechanism shown in FIG. 2, the
section being taken along the line 4--4 in FIG. 3;
FIG. 5 is a fragmentary plan view showing a portion of the endless
belt used in the mechanism shown in FIGS. 2 to 4;
FIG. 6 is a sectional view showing one of the belt drive elements
in greater detail; the section being taken along line 6--6 in FIG.
5;
FIG. 7 is a sectional view similar to FIG. 6 showing another
embodiment of the drive element;
FIG. 8 is a sectional view similar to FIG. 7 showing still another
embodiment of the drive element-belt arrangement;
FIG. 9 is a plan view of the drive element shown in FIG. 8;
FIG. 10 is a sectional view similar to FIG. 8 of a drive element in
accordance with still another embodiment of the invention;
FIG. 11 is a sectional view schematically illustrating the
manufacture of the belt and drive elements of the type shown in
FIGS. 6 or 10, with the mold closed; and
FIG. 12 is a sectional view schematically illustrating the
manufacture of the belt and drive elements, as in FIG. 11, but with
the mold open.
Referring first to FIG. 1, a continuous web 10 is shown in position
for feeding by the feed machanism provided in accordance with the
embodiment of the invention illustrated herein. This web is typical
of the continuous forms used in computer printers. The form has
rows of perforations 12 along its marginal edges which are adapted
to be engaged during feeding.
Feeding is accomplished by two feed mechanisms 14 and 16, each
disposed under the document along the paths of the perforations 12.
The mechanisms are mounted on a pair of parallel shafts 18 and 20.
The shaft 20 is a drive shaft which is adapted to be driven through
suitable gearing or chain drives from a power source, such as an
electric motor. The other shaft 18 is a guide shaft. The feed
mechanisms 14 and 16 are laterally positioned with respect to each
other along the shafts. Accordingly, by moving the mechanisms 14
and 16 closer or further away from each other, various width
documents may be accommodated.
The mechanisms themselves are identical. It is a feature of this
invention that separate right-hand and left-hand mechanisms are not
required. The mechanisms may be used universally either as
right-hand or left-hand mechanisms. Note that the drive shaft 20 is
fluted, while the guide shaft 18 is not. Inasmuch as the feed
mechanisms accommodated both fluted and unfluted shafts, they may
have their positions reversed. Drive will be provided due to the
fluting of the drive shaft 20.
The mechanisms each have frames 22 and 24 which support and define
paths for endless belts 26 and 28, driving elements 30 project from
the feeding surface of the belt. These are the pin portions of the
driving elements 30 which enter the perforations 12 along linear
paths defined by the frames 22 and 24. Drive for the belts is
provided by sprockets 32, 34, 36 and 38; the journalled portions of
which are visible in FIG. 1.
Pivotable guide plates 40 and 42, which have slots 44 and 46
through which the pin portion of the drive elements 30 project, are
to hold the document 10 down against the feeding surface of the
belts. It will be noted that alignment and edge guidance of the
belts 26 and 28 is provided exclusively by the frames 22 and 24.
The guide plates 40 and 42 merely prevent the documents from
blowing off the feeding surfaces. The guide plates 40 and 42 are
mounted on brackets 46 extending from the frames 22 and 24. Springs
48 bias the guide plates 40 and 42 downwardly upon the documents
with minimal hold-down pressure. The brackets 46 and springs 48
together with ears of a U-shaped portion 50 of the guide plates 42
provide a detent mechanism for maintaining the plates 40 and 42 in
the open position (as shown in the case of the plate 40).
Accordingly the plates, when maintained in open position, as for
document loading, will not fall by their own weight on to the
document. The guide plates 40 and 42 must therefore be manually
pivoted downwardly towards the documents to the position shown in
the case of the plate 42.
By virtue of the materials used in the mechanism and the shapes of
the parts thereof, they can readily be cleaned and also can be used
in severe environments where resistance to corrosion, and
cleanliness are problems (viz., in food or drug handling and
processing).
Referring to FIGS. 2, 3 and 4, there is shown the feed mechanism
14. The frame 22 has two side plates 52 and 54. These plates have
holes 54 and 56 for receiving the sprockets 32 and 34 (which may be
installed at either end of the plates -- i.e., in either of the
holes 54 or 56). The plates are secured together in side-by-side
relationship by a spacer bar 58 through which bolts 60 and 62
project.
The upper surfaces 64 and 66 of the plates are accurately machined
to be flat and co-planar with each other. It is in the plane of
these surfaces 64 and 66 that the feeding surface 68 of the belt
lies. Spaced below the surfaces 66 and 68 are shoulders 70 and 72,
which provide support surfaces for the surface of the belt 26
opposite to the feeding surface 68 thereof. The vertical walls 74
and 76 between the shoulders 70 and 72 and the surfaces 64 and 66,
provide for edge guidance of the belt 26 and prevent any lateral
meandering thereof which could cause misalignment with the
perforations in the documents 10 (FIG. 1).
The nature and characteristics of the belt 26 is an important
feature of the invention. The belt is a strip of flexible material.
The material is dimensionally stable and does not have more than
negligible stretch. Other characteristics of the material are low
modulus of elasticity, high tensile strength, high folding
endurance and high melting or combustion point (for moldibility as
will be explained hereinafter). In addition to stainless steel,
titanium, Mylar or Kapton may be used. Kapton for example, has a
tensile modulus of 430,000 psi and its modulus of elasticity is so
low that 13,000 psi of stress produces only 5 percent elongation of
the belt 26, when made of this material. The selection of flexible
belt materials can be made with regard to the above mentioned
characteristics and examples. Metal of course is especially
suitable such as stainless spring steel.
The strip is joined into an endless belt, preferably by overlapping
at the location of one of the drive elements as shown in FIG. 6,
the overlap portion being spot welded at at least two spots 78 and
80 (FIG. 6). Whereas timing belts which are generally available are
made of fibrous material, rubber, nylon, or the like, the belt 26
is of the flexible material having the foregoing characteristics.
It maintains its shape along curvilinear and linear paths defined
by the frame 22, it also presents edges to the walls 74 and 76,
which are stiff and straight and readily guided along the desired
path. The materials are also heat resistant so as to be adaptable
to molding of the drive elements 40 directly thereon as will be
explained more fully hereinafter. Thus, the belt and its associated
drive elements can be provided as an integral structure which can
not change its shape or size over indefinite periods of use and
have chemical and solvent resistance. It and the rest of the
mechanism can even be sterilized.
The belt has perforations (holes) 82 therein at equi-distant
intervals along the belt. These perforations are located along the
transverse of central longitudinal axis of the belt, and the
increments are even-circular pitch increments; the circle being a
circle having the diameter of the sprockets 32 and 34. Inasmuch as
the spacing of the perforations 12 in the documents 10 are
standard, the increments will correspond to such standard
spacing.
The drive elements 30 are disposed in the perforations. These drive
elements project transversely both from the feeding surface 68 of
the belt and from the surface thereof opposite to that feeding
surface 68. The portion of the feeding element 30 which projects
through the feeding surface 68 is the pin portion 84 of the
element. The portion of the element 30 which projects through the
surface opposite to the feeding surface of the belt 26 is the
driving means engaging portion thereof; the driving means being the
sprockets 32 and 34, in this illustrative embodiment of the
invention. These latter driving element portions are in the form of
hemi-cylinders 86, where the diametral surface of the cylinders 86
is in juxtaposition with the surface of the belt 26 opposite the
feeding surface 68 thereof. The hemi-cylinders 86 function as
low-friction rollers in cooperation with the sprockets 32 and 34
and will be referred to hereinafter as the rollers 86.
The driving elements are shown in greater detail in FIGS. 5 and 6.
The pin portion 84 of the element has a cylindrical section 90 over
which a cap 92 portion is located. The cap 92 is a segment of a
sphere which has the same point of generation 94 as the
hemi-cylindrical roller 86.
As shown in FIGS. 5 and 6, the ends of the belt 26 are disposed in
overlapping relationship with their respective perforations 82 in
alignment with each other. The drive element is then formed, as by
molding, in the perforations 82. The overlapping ends of the belt
26 may be secured by spot welding at 78 and 80 prior to or after
molding, preferably prior to molding. As shown in FIG. 5 the
perforations 82 are square or some other non-symmetric shape and
serve to key the drive elements, especially the rollers 86; thus
preventing any interference at the sprockets 32 and 34.
The sprockets 32 and 34 are also interchangeable. The sprockets 32
have fluted holes 95 for receiving either the drive or guide shaft
(FIG. 1). The sprockets have a central portion 96 and cylindrical
side portions 98 which are journalled in the side plates 52 and 54
of the frame 22. As shown in FIG. 3, the central portion 96 of the
sprocket has hemi-cylindrical slots 98 into which the rollers 86 of
the drive elements fit and ride. The slots are at equi-distant
increments along the pitch circle of the sprocket fluted portion
96. The rollers 86 thus roll while driven and have minimum
frictional contact with the sprockets.
The drive elements are preferably made of low-friction material
such as nylon. It has been found that the plastic material sold by
General Electric Company of Schenectady, New York, under their
Trade Name VALOX is especially suitable.
FIG. 7 illustrates a drive element 30 having a pin portion 84
including a screw tip 100 which screws into a threaded hole 102 in
the roller portion 86, such screw fitting being a feature of the
embodiment of the drive element illustrated in FIG. 7.
In FIG. 8 the belt 26 is formed with a downwardly projecting path
104 which fits into a slot 106 in the roller portion 86 of the
drive element 30. The drive element 30 illustrated in FIGS. 8 and 9
has a pin portion 84 and roller portion 86. The pin portion has a
lip 108 of square configuration which slopes downwardly from the
pin portion 84 towards the roller portion 86 and defines a slot 110
into which the perforations 82 in the belt 26 may fit. The element
30 illustrated in FIGS. 8 and 9 is snap-fitted into the belt 26, by
pressing the pin portion 84 upwardly through the perforations 82
until the belt lies over the lip 108 and snaps into the slot
110.
FIG. 10 illustrates a drive element 30 similar to the drive element
illustrated in FIGS. 5 and 6. The belt 26 however is formed with
tabs 112 at each perforation 82 to firmly anchor the drive element
in the belt and prevent rotation or other movement of the element
during operation of the feed mechanism. The element 30 and belt 26
as shown in FIG. 10, may be formed by molding, as was the case of
the element shown in FIGS. 5 and 6.
The method of manufacturing the belt 26 and drive elements 30 by
molding is illustrated in FIGS. 11 and 12. FIGS. 11 and 12
illustrate the manufacture of the belts by injection molding. The
mold shown in FIGS. 11 and 12 shows the belt 26 with the mold in
closed and open positions. The mold itself is a three-part mold
having a base 114, a top 116, and a center portion 118. An
injection nozzle 120 is provided for feeding hot plastic material
into the mold through a channel 122 formed when the mold is closed.
It will be apparent that the molding process illustrated in FIGS.
11 and 12 may be accomplished very rapidly to mold each of the
drive elements into the perforations in the belt 26 in very rapid
sequence, and yields a molded-through belt assembly, which resists
contact with abrasive material, such as the paper of many computer
forms.
From the foregoing description it will be apparent that there has
been provided improved feed mechanisms which have the advantage of
highly accurate and high speed feeding of movable members,
especially computer forms which are perforated. An important
advantage of the invention is that feed mechanisms in accordance
therewith may be readily manufactured at low cost. While an
illustrative embodiment of the invention has been disclosed herein,
it will be appreciated that variations and modifications thereof
within the scope of the invention will undoubtedly suggest
themselves to those skilled in the art. Accordingly, the foregoing
description should be taken merely as illustrative and not in any
limiting sense.
* * * * *