Note: Descriptions are shown in the official language in which they were submitted.
FIELD OF THE INVENTION
This inventlon relates to file -Folders, file
backers and the like used in filing systems and more
particularly to such folders, backers and the like having
at least one reinforced edge for use in such systems.
BACKGROUND OF THE INVENTION
With the ever increasing use and popularity of
colour coded filing systems in offices there is a decided
trend to the USE of side tab folders. Side tab folders
should be distinguished from top tab folders. Top tab
folders are indexed on the upper edge parallel to the
spine or fold between the front and back surfaces of the
folder. Side tab folders are indexed on teh side at right
angles to the spine or fold. The file folders are placed
upright on shelves with their side edges projecting
outwardly from the shelf. Side tab filing systems have
become most advantageous, especially in larger filing
systems, because the filing and finding of folders is
faster and easier. Also, side tab filing systems save
floor space as compared ~ith drawer filing. ~I~he colour
coding of the files is not a necessity but can usually be
an enhancement. The reinforced edge can advantageously be
used in either top or lateral systems.
An example of side tab file systems is disclosed
in United States Patent 4,204,639. Usually file folders
remain in a filing system for many years and during the
life of the folder are subjected to considerable wear and
tear and often to severe handling and abuse. Also, as
they are moved between the file room to the user
departments they are often roughly handled as they are
temporarily placed in holding baskets or carts with the
side tab projecting. This projecting tab is exposed and
thus vulnerable to creasing, tearing and fatigue.
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The folder stock commonly used for file folders,
backers and the like is a folder stock approximately .011
inches or .014 inches thick. The folders are manufactured from
web stock on high speed automatic folder machines.
In the past, many attempts have been made to reinforce
file folder edges, especially the top tab type which have been
commonly used for many years and are stored in file drawers.
Usually the upper edge of the file folder is reinforced in one
way or another to withstand abuse. An example of such file
folder reinforcement is disclosed in United States Patent
1,743,191. In that instance, the upper edge of the rear panel
of the folder has an additional layer of file folder stock
glued to the upper edge and wrapped around the upper edge of
the folder to provide a three ply thickness to substantially
reinforce the upper edge. Other examples of similar manners
for reinforcing file folder edges, are disclosed in United
States Patents 1,081,727; 2,052,623 and 2,138,788. In each
instance, either the file folder stock integral with the folder
is folded over and glued to reinforce the edge or additional
material is added of the same file folder stock to reinforce
the edge.
The approach to date has, therefore, been to add
additional layers of the folder stock to the folder edge in an
attempt to reinforce and add stiffness to the folder edge to
resist tearing.
Various forms of high tensile strength filmc have been
used to repair rips in paper and protect surfaces of paper
products. An example of such film is Mylar (trademark) which
consists of polyethylene terephthalate and is sold by Du Pont.
In the File folder field, such film is used to protect add-on
file folder tabs as disclosed in Canadian Patent application
--2--
D
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S.N. 380,208 filed June 19, 1981, now Canadian Patent 1,138,~88.
It has been discovered as discussed below that this
type of high tensile strength film may be bonded to the edge of
a file folder to unexpectedly greatly increase the strength of
the folder and its resistance to tear. Because of the thinness
of the film, little bulk is added to the folder thickness and
the film may be conveniently applied during the manu~acture of
the file folder. By using coloured adhesives, which may be
applied to a clear film just prior to bonding the film to the
folder edge, the edge of the folder front and back panels may
be provided with a distinct colour to which colour coded labels
may be subsequently applied. An alternative to a coloured
adhesive is to use a coloured paper on the folder edge which is
covered by a clear film. Another alternative is to use
coloured film which is secured to the folder edge to provide
the des red colour band. This is a significant advantage in
that groups of files of a file system may now be recogni~ed by
the complete band of colour down its front and back panel
edges. This avoids the prior more costly approach of using
many different coloured folder stocks for dis-tinguishing each
desired group of files in the system. Such coloured paper
stock would fade and loose its distinctive colour. In
addition, the colour of the folder stock would change frorn
batch to batch of the stock, so that there would not be a
consistent colouring for a group of files.
The folders can be manufactured from web stock on high
speed automatic folder machines where the high tensile strength
film when bonded to the edge of a file folder unexpectedly
greatly increases the strength of the folder and its resistance
to tear. This advantage can be accomplished during the folder
manufacturing process in a way that only marginally increases
the manufacturing
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cost. This marginal cost factor in relation to a much
superior file folder is a worthwhile and important advantage.
Such high tensile strength film compliments and increases
additionally the strength of a folder edge which consists of
ploughed over web stock to provide a double thickness of paper
stock at the edge. Also, -the high -tensile strength film
provides a superior bonding surface for the attachment of the
self adhesive indexing and colour coded labels used to
identify the folders.
SUMMARY OF THE INVENTION
The present invention is directed to file substrates
of paper stock, of the type for receiving recorded information
for future reference. This file substrate has at least one
straight edge integral with such file substrate intended to
subsequently receive adhesively applied labels, for
identifying the substrate. A tear resistant plastic film is
applied about the straight edge and secured either side of the
straight edge to reinforce the substrate adjacent the straight
edge. The film provides a receptor surface for receiving
labels to the exterior thereof. The film is confined to a
limited region of the file substrate adjacent to and including
the straight edge and continuously extends at least
essentially the length of the straight edge.
According to an aspect of the invention, the at least
one straight edge has been folded and bonded to itself with
said film to the exterior thereof to provide a double
thickness of paper stock.
According to a further aspect of the invention, the
film is a high tensile strength film which is adhesively
secured to the substrate to effectively secure the film in its
length and width directly to the file substrate.
A method for producing a reinforcing edge of a file
substrate of paper stock according to the present invention
comprises
applying and securing a plastic film to one surface
of the substrate ~nd continuously along one straight edge
thereof, folding the substrate and film in the length of the
film and the straight edge to produce two opposed paper stock
portions with film to the exterior thereof at least
essentially the full length of the straight edge, and securing
the opposed paper stock portions.
In a preferred embodiment of the invention, the file
substrate is a file folder of paper stock having a body
portion folded to form a generally rectangular front panel and
a generally rectangular back panel. One of the panels has an
integral identification extension on one side thereof. This
extension and a portion of the panel adjacent the extension
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s
has a high tensile streng-th plastic film adhesively secured
thereto. The film extends either side of the one panel about
the edge of the extension, and across the junction of the
extension and the one panel to reinforce -the extension and
junction. The film is continuous and extends at least
essentially the length of the extension.
The preferred embodiment can be modified such that
the plastic film is also secured either side of the other
panel at the edge adjacent the extension to reinforce the file
folder at the extension and the fold in the body portion.
According to an aspect of the invention, the method
of producing file folder blanks made of paper stock having a
reinforced edge portion comprises withdrawing a paper s-tock
web of a prede-termined width from a supply roll,
securing a continuous high tensile strength film to
one surface of the paper stock web and at least essentially
along the full length of one edge thereof,
applying an adhesive on the surface of the paper
stock web opposite the high tensile strength film,
folding the paper stock web and film upon itself in
the length of the film to form an adhesively secured
reinforced edge portion having a thickness about double the
thickness of the paper stock and bound on the two exterior
surfaces and about the edge with the high tensile strength
film,
and cutting the paper stock and -the paper stock and
film to form individual file folders blanks.
According to yet a further aspec-t of the invention7
the method above includes cutting the reinforced edge portion
of the folder blank to form a desired folder blank edge
profile.
According to another preferred embodiment of the
invention, the file substrate is a folder blank which when
folded about its mid-section forms a folder having a
reinforced side tab for use in a lateral file system. The
folder blank is generally rectangular folded paper stock which
is die cut from a web of such paper s-tock. Q longitudinal
side of the blank includes a projection of folded and secured
paper stock which provides the folder side tab when the blank
is folded. A continuous length of high tensile streng-thg tear
resistant reinforcing film is adhered on both sides of -the
blank along the full length of the blank longitudinal side to
reinforce -the side along its length. The -film is confined to
a limited edge region of said blank adjacent to and including
the blank longitudinal side.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiment of the invention are shown in
the drawings wherein:
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Figure 1 is a perspective view of a file folder
having a side portinn reinforced in accordance with this
invention;
Figure 2 is a plan view of web stock which has an
edge thereof reinforced with film and from which folder
blanks are die cut;
Figure 3 is an enlarged view of the undercut
portion of the side tab as it projects from the rear panel
of the file folder;
Figure ~l is a perspective view of the enlarged
portion of the undercut as shown in Figure 3 5
Figure 5 and 6 show other arrangements for file
folder side tab portions as reinforced in accordance with
this invention;
Figure 7 is an enlarged view of the undercut
portion of the file folder side tab arrangement of Figure
5;
Figure 8 is a perspective view of apparatus for
applying reinforcing film to the side edge of a moving web
from which the folder blanks are die cut,
Figure 9 is a perspective view showing the
application of a film having fresh adhesive applied
thereto;
Figure 10 is a side elevation of the machine for
applying and drying adhesive on the film for appli.cation
to folder stock web;
Figure 11 is a partial view of the apparatus of
Figure 10 showing devices for drying the adhesive on the
film;
Figure 12 is a perspective view of the device for
applying a thin layer of adhesive to the film;
Figures 13a, 13b and 13c are a series of partial
sectional views through the edge of a file folder
diagrammatically illustrating several manufacturing steps;
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Figure 14 is a partial perspective view showing
an alternate method of applying the film to the paper web
stock;
Figure 15 is a partial perspective view of the
web stock and film being folded upon itself after
application of an adhesive to the opposite face of the web
stock relative to the surface carrying the high tensile
strength film;
Figure 16 is a perspective view of a folder blank
with the plastic film secured about the reinforce~ edge;
Figure 17 is a partial perspective view of a
folder blank similar to Fi.gure 16 having a portion of the
reinforced edge removed to define a label securing portion
on the remaining reinforced edge;
Figure 18 is a section through a modified
apparatus for applying adhesive to the lower sur-Face to
the high tensile strength film and subsequent drying of
the film prior to securement of the film to one surface of
the paper web stock; and
Figure 19 is a perspective showing a roller used
to align the film with the previously aligned paper web
stock.
DETAILED DESCRIPTION OF THE PREFERRED EMBODlMENTS
The file folders as reinforced in accordance with
this invention optionally having colour banding applied
thereto are particularly useful in lateral filing
systems. Such filing systems differ from the standard
drawer type in that the file folders are placed on shelves
and stand upright as they rest on the spine portion of
each file~ Only the side edges of the file folder project
from the shelf where each folder side edge carries labels
or a label defining the code for the file. It is possible
to use colour coded labels with this system to provide an
orderly colour array in which misfiles are easily
spotted. Details of this system are discussed in
previously mentioned United States Patent 4,204,639.
Referring to Figure 1, a file folder 10 for use
in a lateral file system is shown. File folder 10
comprises a back panel 12 and a front panel 14. rhe back
panel 12 has a top edge 16 and side edges 18 and 20.
Similarly, the front panel has top edge 22 and side edges
24 and 26. The bottom edges of front and back panels are
interconnected at the fold or spine portion 28. A
reinforcing film 30 is applied to both the top and bottom
surfaces of panel edges 20 and 26 in the manner shown, to
reinforce the folder side generally designated 32 along
the length of edges 20 and 26. Reinforcement of edge 32
includes reinforcing the projecting tab to decrease damage
by creasing or folding causing weakening and separation of
the layers making up the web stock as well as reinforcing
of the area securing the tab to the panel. lhis second
type of reinforcing is accomplished by having a portion of
the film overlie the paper web panels to distribute the
local forces exerted on the tab to a larger area of the
file folder. In addition, labels 34 are applied over the
film 30 to designate at least in part a code for the file
folder. In accordance with the aforementioned United
States Patent 4,204,639, these labels may be colour coded.
The file folder 10 is formed from a file folder
blank which in turn is cut from a web of file folder
stock. As shown in Figure 23 the file folder stock 36 is
a web having side edges 38 and 40. The web stock 36 has a
reinforcing film 30 applied along side edge 40. The film
30 is wrapped around web edge 40 and secured to each
surface, that is top and bottom surfaces, of the web stock.
Various configurations may be used in providing a
folder side for use in a lateral file system. As per the
arrangement shown in Figure 1, folder side 32 is formed by
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cutting web side 40 within the width of film 30 along edge 26
to provide a cut-out portion 42. Depending upon the type of
cutting mechanism used, the folder blank 36 is cut from the web
along lines 44 and 46 either simultaneously with cutting sides
40 or cut subsequen-tly at another station. Such cut-out blank
is subsequently folded along line 28 to form the folder of
Figure 1. With portion 42 cut from the web to define the side
tab or identification extension 32 of the Folder, an undercut
portion 48 having a curved transition edge is provided at the
Fold line 28. It is this portion of the folder side which is
most susceptible to wear and tear and can be ripped as the
folder is used in lateral file systems, carrying baskets, carts
and the like.
Turning to Figure 3, the undercut portion 48 is curved
at 50 to reduce sharp edges which are more likely to tear.
That in conjunction with the reinforcing film 30 considerably
strengthens the undercut portion 48 to minimize tearing of the
folder in this area. In addition the outer edge of the
undercut area is sloped at 49 to avoid fraying and splitting of
this portion of the side tab. From the standpoint of cutting
the outer edge, the sloped portion 49 is more accurately cut
than a radius because the die cutting edge may extend well
beyond the folder edge. This ensures a clean cut to the outer
edge of the folder side even if the web should shift slightly
laterally before being cut.
In the enlarged view shown in Figure 4 the web stock
material may have a side edge folded over to provide double
thickness of material along the edge. The web stock edge
there~ore has an underlying layer 52 which has adhesively
secured thereto a folded over upper layer 54 which has an inner
edge 56. The reinforcing film 30 is secured to the surfaces
along the side edge 40 of the web. The reinforcing film 30 is
wrapped around the edge
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y ~ r~- t -
1~ d
where the film ls of a sufficient width to extend beyond
the inner edge 56 of the folded over web stock material.
Thus, the side tab portion 32 of the folder to be made has
the reinforcing web wrapped therearound. In the area of
the undercut 48 and outer edge 49, the film has been cut
so as to be flush with corresponding cut web portions 52
and 54. It has been found that by adhesively securing the
film to these portions of the folder stock and cut flush
with the undercut edges, the likelihood of ripping the
10 ~older in -this undercut area and along the remainder of
the folder side is minimized due to the significallt
increase in strength of the folder side by way of the
reinforcing film.
Referring to Figures 5, 6 and 7, alternative
15 arrangements for file folder side portions for use in
lateral file systems are shown. In Figu e 5, side region
58 of a file folder comprises rear panel 60 and front
panel 62. Projecting outwardly f-rom rear panel 60 is side
tab 64. A reinforcing film 66 is applied to both surfaces
20 of the side tab 64 and also along both surfaces of the
edge 68 of front panel 62. The reinforcing fllm 66
reinforces the entire side of the folder 58, particularly
the area of undercut at 70 where the shorter front panel
62 intersects the longer rear panel 60. As shown in
25 Figure 65 file folder portion 72 has corresponding rear
panel 74 and front panel 76 with side tab 78. Film 80 is
secured to both surfaces of the front and back panels to
reinforce the panel side and particularly tne undercut
portion 80. In the embodiment of Figure 6 the undercut
30 portion is located upwardly from the fold line or spine 82
of the folder.
Referring to Figure 7 an enlarged portion of the
undercut area 70 of the folder 58 of Figure 5 is shown
where the film 66 is secured by an appropriate adhesive to
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both surfaces of the front and back panels GO and 62. In
the area of the undercut 70, the notch 84 is protected by
the film 66 secured -to both surfaces surrrounding the
notch 84 to prevent or minimize tearing of the folder side
in this area.
Various techniques may be employed for securing
and applying the reinforcing film to -the edge portion of a
file folder. The film itself may be provided in the form
of a roll already having an adhesive on one face thereof,
or the film may have applied thereto the adhesive with the
film subsequently directly applied to folder w~eb stock
material. The desirable forms of adhesives ~the
pressure sensitive type where, if the adhesive is applied
to the film and re-rolled the adhesive has less affinity
for the film to which it is applied than for the paper
stock material to which it is subsequently appliedO
Referring to Figure 8, a machine is shown which withdraws
film having already applied thereto a pressure sensitive
adhesive for securing the reinforcing film to the paper
stock material. The film is of a high tensile strength
tear resistant type. An example of such film is
polyethylene terephthalate which is sold by Dupont under
the trademark "Mylar".
The web stock 86 is withdrawn from a supply roll,
not shown, and fe~ in the direction of arrow a8. lhe web
stock has side edge portions 90 and 92. On side edge
portion 92, an adhesive 94 is applied by adhesive
application wheel 96. The web stock edge 92 is folded
over in the direction of arrow 98 and adhered to itself by
a device not shown to provide a double edged portion along
the web stock 86. This will in turn form the side edge of
a folder of the type shown in the enlarged view of Figure
4.
A supply roll 100 of reinforcing tear r~sistant
11
'7.~-5
plastic film having a pressure sensi-tive adhesive aiready
thereon is mounted on a spindle 102 of the film
application apparatus 104. Nip rollers 106 and 10~
withdraw the film 110 from the supply roll 100. ~The
rollers 106 and 10~ are driven by a motor 112 the speed of
which is coordinated with the rate of feed oF the web
stock 86 in the direction of arrow 88 to withdraw and ~eed
the film 110 at a linear speed equal to the speed at which
the web stock 86 is travelling in the direction of arrow
88. 1he film 110 is passed over a spring loaded arm
having a roller 114 to compensate for slack in the film
due to variations in the speed of the web stock 86 should
the motor 112 not be capable of quickly compensating for
variations in speed of the web stock 86.
The film is then passed over a series o~ standard
rollers generally designated 116 which are usually used to
fold the fi].m over edge 118 of the web stock and apply it
to both surfaces along the edge. The roller system 116
comprises a first vertical planar roller 120 which presses
the film against the edge 118 of the moving web stock 86.
Although not shown, a spring loaded device or a moveable
guide is placed on the other side of the web to constantly
urge the web against the roller system 16. The film 110
is gradually creased at the edge 118 of the web stock 86
by grooved roller 122. Planar vertical roller 124
maintains the slightly creased film against the edge of
the web stock where roller 126 having an accentuated
grooved portion creases the film further to essentially
overlie both surfaces of the web stock along the edge
3~ 118. Vertical roller 128 maintains the film in this
position as opposing compression rollers 130 and 132 press
the film with pressure sensitive adhesive agalnst the web
stock material. With the film now adhered to bo-th
surfaces along the side edge of the web stock it is ready
~5
'7~
for cutting to form the desired side tab shape. As the
web stock continues to move, a standard device (not shown)
is used to cu-t out from the web stock, edge portion 134
which resembles the shape of cut out 42 as shown in Figure
2 in forming the side tab arrangement -for the file folder
of Figure 1. The file folder blank is cut from the web
stock along lines 136 and 138 and folded about its mid
section along fold 140 to form the folder of Fiyure 1.
In situations where it is desired as
aforementioned to provide a colour band along the side tab
of the file folder, the machine and method according to
this invention does this including changing the colour
applied to folders with minimal difficulty. This may be
accomplished by selecting a coloured adhesive which is
applied to a clear reinforcing film and which is in turn
applied to the file folder. As already mentioned,
however, one may instead of using various coloured
adhesives to determine the colour of the band along the
folder side, use a reinforcing film which is itself of the
desired colour. Such coloured film may then have clear
adhesive applied thereto by the machine and method
according to this invention, or have adhesive previously
applied and re-roi.led. In the latter instance with the
coloured -film having the adhesive already thereon, such
film may be applied to folders by using an apparatus such
as that shown in Figure 8.
The width of the film applied to the web stock
edge or the Folder side may vary dependiny upon whether it
is a clear film or a coloured arrangement to provide the
band of colour. As shown in Figure 1, a significant
portion of the exterior of the front flap 14 includes the
Mylar film as with the exterior of the rear flap 12O lhus
when the folder having the band of colour appl.ied thereto
is lying on a desk either right side up or upside down,
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7~55
the large band of colour designates clearly t~le group of
files to which it belongs. To ensure a sufficient width
of colour band, for example with a four inch width of
film, two and a half inches may be applied to one surface
of the web stock, which constitutes the exterior of the
fron-t and rear panels, and one and a half inches to the
remaining surface which constitutes the interior of the
front and rear flaps. Such one and a half inch overlap is
sufficient, as already explained with reference to Figure
4, to cover the doubled over portion of the folder edge.
Such difference in widths of the film as applied to each
side of the folder stock is shown in Figure 2 by the
dotted line which signifies the width of the film applied
to the other side of the stock. This extra width of film
also serves to distribute forces exerted on the tab to a
larger area of the panel and reduce the possibility of
tearing of the tab from the folder.
Referring to Fiyures 9 and 10 a machine is shown
which allows the use of various coloured adhesives so that
the folder side tab is of a desired colour. ïhe adhesive
applicator device of Figure 10 supplies t~e transparerlt
film which as shown in Figure 9, moves in a downward slope
and is secured onto a web which is conveyed to the
machine. As with the device in Figure 8 the web stock 142
is conveyed over framework 144 and over a support 146. A
glue applicator roll 148 applies glue to an edge 150 of
the web 142. A device (not shown) is used to plough over
the edge 150 ln the direction of arrow 152 and rollers are
used to lay down and secure the folded over edge portion
154 of the web stock 142. The adhesive used is such that
the folded over edge portion 154 remains flat after
passing between spring loaded pressure rollers 156 and
158. The film is of sufficient width and secured to the
web 142 in a manner so as to extend beyond edge 160 of the
s
-Folded over portion 154 such that when tile film 162 with
pressure sensitive adhesive on its underside passes
between the web edge 154 supported by roller 158 and the
spring loaded roller 156, it is secured to the web edye
and overlaps the edge 160 of the folded over portion of
the web stock.
The film is then wrapped around and onko the
undersurface of the web stock in a four-stage process.
Having secured a portion of the width of the filrn 162 to
the upper surface oF the web stock, the accurate location
of the film relative to the web stock is now deterrnined.
According to the example of a four inch width of film, one
and a half inches of the film width is laid onto and
secured to the presented surface oF the folder stock. lhe
next stage is to fold over the remaining two and a half
inches of film which is commenced by roller 164 having
bevelled face portion 166. Bevelled face 16~ bends the
film downwardly at an angle relative to the plane of the
web stock. The next stage in bending the film is provided
by vertical roller 168 which bends the film to a 90 degree
angle relative to the plane of the web stock. The next
stage of the fold over is provided by roller 170 having
bevelled face 172 which begins to fold the film underneath
the web stock at an acute angle relative to the underside
of the plane of the web stock. The film, as bent under
the web stock, can now be passed throuyh spring loaded
pressure rollers 174 and 176 to cornplete the securement of
the folded over film to the web stock. The overall length
of the roller arrangement 178 is sufficient to ensure a
~0 smooth wrap around the film without creases therein. The
web stock ls now ready for the next stage in manufacture,
namely the die cutting thereof to provide the desired
Folder side shape and cut the folder blank from the web
stock in a manner which is commonly used in the art. In
S5
instances where a clear film is applied to the web stock,
a narrower film width may be used because of the
nonrequirement of a large colour band. A th~ee inch clear
f`ilm may be used wl~ere the film is folded over equally on
both surfaces of the web stock to reinforce the edge.
Turning to Figure 10, the relative location of
the roller arrangement 178 for applying the film 162 to
the web is shown. Above the roller location is the
apparatuS 180 for withdrawing film from a supply roll,
applying adhesive thereto and drying the adhesive
preparatory to application of the film to the web stock
142 by the roller arrangement 178. The film 162 is
withdrawn -From a supply roll 182 which is supported on a
spindle 184 which in turn is secured to a mainframe 186.
The second spindle 188 is provided to carry a second
supply roll 190 so as to be spliced with the film 162 when
it is completely withdrawn from the first supply roll
182. The spindles 184 and 188 are adjustable laterally to
accommodate various sizes of filnl width for use on the
machine. The film 162 passes under roller 192 and over
the remaining several rollers which serve to pass the film
through the machine in applying and drying adhesive
thereon. Rollers 194, 196 and 198 provide a path for the
film so as to move vertically downwardly onto roller 200.
To provide a predetermined tension in the film 162
sufficient to maintain the film without creases, a spring
loaded roller 202 is provided as urged downwardly by
spring 204. Roller 206 operates in conjunction with
roller 200 to pass the ~ilm over adhesive application
roller 20~ which picks up adhesive from an adhesive tray
to be described in more detail with respect to Figure 12.
A sensor is used to de-termine when the web
movement is s-topped such as a sensor on the rolls for
moving the web (not shown) so that when they stop a
16
5~3
pneumatic cylinder 210 is actuated to retract upwardly
roller 200 about hinged arm 212 to move the film 162 away
from the adhesive application roll 208 which continues to
rotate and circulate adhesive in the tray. This prevents
wearing of the film and build-up of adhesive on the film
during line shutdown.
As the film passes over the roller 208 a thin
layer of adhesive is applied to the outer surface of the
film 162. Thus the remaining series of rollers 214 and
corner guide rollers 216 pass the web upwardly, across and
downwardly to a final bottom guide roller 218.
The adhesive which is applied to the film may be
of the water base type which is an emulsion oF pressu-ie
sensitive adhesive solids in water. The layer of pressure
sensitive adhesive on the film must be dried so there is
little moisture left in the layer when applied to the
folder to ensure a good bond with the folder material. To
ensure that the adhesive is relatively dry, considering
that the film may be moving at speeds in the range of 150
to 200 feet per minute, hot air is directed onto the
adhesive through tubes 220 about the perimeter of U-shaped
plenum 222 which carries hot air from hot air blowers
shown in dotted at 224 and 226.
The structure of the tubes 220 and the plenum 222
is shown in more detail in Figure 11~ A hot air blower
226 blows air into a hollow rectangular plenum tube 222
which is closed at its ends 223. The tubes 220 have a
series of ports 228 which direct -the hot air onto the
surface 230 having the layer of adhesive on the film 162.
The two hot air blowers 224 and 226 supply sufficient hot
air through the ports 228 so that the adhesive is dried
when it passes over exit roller 216 of the drying chamber
arrangement. A shield 215 is provided about the perimeter
of the U-shaped plenum 222. The shield extends slightly
17
t;~ jtj
greater than the length o-f the rollers 214 to shield the
film as it passes over such rollers from ambient air
currents which may be laden wlth dust and other
contaminants. To guide the path o-f the film throuyh the
5 drying chambe~ arrangement, each corner guide roll 216 has
a pair of rings 2~2 as shown in Figure 11 which are
adjustable along the axis of the roller 216 so as to
determine the lateral position of the film on these guide
rollers and thereby direct the film about the perimeter of
the U-shaped drying arrangement. Similarly 9 on rcller 218
rings 234 are provided to locate the film 162 relative to
tlle web stock 142 in properly positioning it for
application to the file folder. Such ring in providing
film position adjustment thereby accommodates various
widths of film to be applied.
Turning to Figure 12, the adhesive applicator
device 234 comprises the driven roller 208 which applies a
thin layer of adhesive to the film 162. The roller 208 is
driven by a drive arrangement 236 which is synchronized
with the speed at which the film passes through the
apparatus 180 that is~ the linear speed of the web stock
142. Thus, the roller 208 is rotated at a speed so as to
have a peripheral linear velocity corresponding to the
speed at which film 162 is moved through the apparatus
180. In synchroniziny the speed of the drive 23~ it will
correspondingly vary the speed of the roller 208 depending
on variations in the speed of the movement of the web
stock 142.
A doctor blade 238 with caliber adjustments 240
and 242 determine the thickness of the adhesive layer
picked up by the roller 208 from the adhesive tray 244.
As mentioned, the drive 236 rotates at all times even
during temporary stoppage of the line to circulate the
adhesive in the tray 244. The tray 244 is removable from
18
7 ~
the adhesive applicator device 234 by loosening of knurled
knob 246 which fits in inverted L-shaped slot 248. Upon
loosening of the knob 246 tray may be moved forwardly and
downwardly from the supportive framework 250 of the
adhesive applicator device 234.
When it is desired to change colours of adhesive
applied to the film 162, the adhesive tray 244 is removed
and replaced with a different tray having a different
coloured adhesive therein. When the tray is removed,
access to roller 20~ is gained to remove any remaining
colour from the roller before applying the next coloured
adhesive.
Since the adhesive is a water based type, the
sensor which retracts roller 200 so that there is not a
build-up of adhesive on the film 162 durit-ly line shutdown
can also be used to turn off blowers 224 and 226 so as to
not overdry or deteriorate the adhesive applied to the
film. Therefore the line may be shutdown safely without
damaging the adhesive applied to the film. On start-up
the hot air blowers are reactuated to direct hot air onto
the film to complete any necessary drying and continue to
dry fresh adhesive as applied to the film emerging from
roller 206 of the system.
The apparatus according to this invention is
therefore useful in selectively applying a predetermined
coloured adhesive to the film 162 before application to a
folder. This provides the significant advantages of not
only reinforcing the folder edge but also providing a
desired coloured band along the folder edge to designate a
group of folders in a file system having many different
groups. A further advantage in using a coloured adhesive
or a coloured film is the colour fastness of the band on
the folder. Unlike coloured paper stock which will fade
in sunlight, the colour band as provided by this invention
19
~9~7~S~
does not fade. In addition, the control on the colour is
more consistent because of the accuracy enabled in either
colouring the film or the adhesive compared to a
batch~to-batch process in making colour paper stock.
A further consideration in providing the coloured
ban is to have coloured paper on t~le web s-tock edge and
covered by the Mylar film. Ti~e colour oF the paper shows
through the clear film to provide a desired colou~ band.
The colour paper may be secured to the Mylar film and the
paper, in turn, be secured to the folder edge or
conversely, the coloured paper may be secured to the
folder edge and the Mylar applied over the coloured paper.
The plastic reinforcing film must, when applied
to the paper web stock, reduce the tendency of the tab or
edge to be torn from the paper web stock and distribute
forces such that creasing and folding of the tab or panel
adjacent the tab are reduced. Films which are suitable
include, polythelene terephthalate films such as sold by
Dupont under the trade mark Mylar, "Celanar" (trade mark)
from Celanese and "Scotchpar" (trade mark) from 3M.
Figures 13 through 19 illustrate a varia-tion of
the method of manufacturing the product as well as a
variation of the apparatus. For this reason, a new
numbering scheme will be used. ~eferring to Figures 13,
14 and 15 the web 300 of paper web stock is advanced from
a roll not shown and undergoes a number of operations to
produce the file folder blank 302 shown in Figure 16 or
the modified Folder blank 302a shown in Figure 17. The
difference between the folder blank of Figure 16 and that
of Figure 17 is that a portion of the reinforced e~ge has
been removed ~rom the front panel 308 to thereby define an
outward extension portion 305 on the front panel 310. As
in the earlier figures the reinforced edge 303 has a high
tensile strength reinforcing film 312 secured about the
D ~ q~ty ~
straight reinforced edge 303 with a portion of the film
extending beyond the reinforced edge to be in direct
contact with the portion of the web stock 300 adjacent the
reinforced edge. In this way, rein-forcement of the file
folder adjacent -the junction of the reinforced edge 303
and the abutting paper stock is achieved. This serves to
distribute localized forces exerted on the outward
extension 305 to the file foder and thereby avoid
localized deterioration of the extensionO
In Figure 13 the high tensile strength film 312
has been adhesively secured in this case to the lower
surface of the paper web stock as generally shown in
Figure 14 and an adhesive 314 has been applied to the
opposite surface of the paper web stock for adhesively
securing the paper web stock which will be Folded upon
itself. Therefore the paper web stock with the film on
the lower surface thereof is folded upon itself -to produce
a reinforced edge portion with the high tensile film
secured along the length either side of the reinforced
edge and about the edge thereof. This defines two opposed
surfaces of pa,oer web stock indicated as 316 and 31~ which
are secured by adhesive 314 to provide a double thickness
o~ paper web stock adjacent the edge of the file folder.
It should be noted that the paper web stock and film are
not folded in the center line of the film as it is
preferable to have the film extend across the junction of
the reinforced edge and the paper web stock to rainforce
this and reduce the tendency of this reinforced area to be
torn from the remaining body of the web stock.
Application of the high tensile film to the lower
surface of the paper web stock and the subsequent folding
of the film and paper web stock is shown in Figures 14 and
15, The high tensile strength film 312 is secured by an
adhesive 311 to one surface of the paper web stock ~00
21
7 ~5
adjacent the edge thereof, in this case to the lower
surface of the paper web stock, as the web stock is
advanced. This advancement is generally indicated by
arrow 320 showing movement of the paper web stock and
arrow 321 showing movement of the high tensile strength
film with adhesive applied there-to. A paper web stock
aligning device 322 accurately maintains alignment of the
paper web stock as it is being withdrawn from the supply
roll. One such aligning device is manufactured by
ln G. W. D. Controls Limited and is referred to as a paper
stock guide. This apparatus accurately maintains the edge
o~ the paper web stock and therefore a manual aligning
roller generally shown as 330 in Figure 14 can be used to
align the high tensile strength film with the edge of the
paper web stock to assure placement of the film adjacent
the edge of the web stock. Further details of the
alignment roller 330 can be appreciated from a review of
Figure 19.
The high tensile strength filrn 312 is applied to
the lower surface of the web stock 300 and is retained on
the web stock as it is passed between pressure rollers 340
and 341. This assures the pressure sensitive adhesive 311
firmly bonds the high tensile strength film to the lower
surface of the paper web stock. In applying the high
tensile strength film, it is important to control the
tension thereof to assure the film is not highiy
prestressed as it is applied to the paper web stock. It
is preferred to merely apply sufficient tension to
maintain the film flat as further stressing of the film
will occur when the folder blank is folded to form front
and back panels. Prestressing of the film can cause
buckling of the paper stock. In contrast to the earlier
apparatus, the high tensile strenth film is not driven but
merely advanced by the web stock.
7:~5
A further adhesive ~ is then applied adjacent
the edge of the paper web stock and is used to secure the
paper web stock portions 316 and 318 as shown in ~igure
13. After the adhesive 314 has been applied, the web
stock is passed through a number of folding rollers
generally designated as 350 to fold the paper web stock
upon itself and subsequen-tly pass the folded web stock
through pressure rollers 352 and 354 in order to strongly
adhere -the paper web stock portions 316 and 318.
After completing the folding of the paper web
stock with the film on the exterior surface thereof, the
paper web stock is passed through a number of cutting or
blanking operations to form folder blanks generally as
shown in Figure 16 and Figure 17. In the embodiment
shown, a fold line 370 has been produce on the folder
blank 302 and 302a to thereby define front and back panels
of the file folder. By removing a portion o-f the
reinforced edge 303 as shown in Figure 17, a file folder
having a laterally extending portion 305 is produced
suitable for use in lateral filing. However it can be
readily appreciated that the fold line 370 could have been
formed in a direction perpendicular to that shown to form
a top readable system and therefore the present method and
apparatus is not limited to file folders for use in
lateral filing systems.
Figure 18 shows a modified apparatus for
advancing the high tensile strength film passed an
adhesive applying roller which applies a thin film of
pressure sens~tive adhesive emulsion to one surface of the
film and subsequently dries the applied emulsion
sufficiently to strongly adhere the film to the paper web
stock. The apparatus includes a supply 360 of high
tensile strength film, with the film 312 being threaded
throuyh a number of roller prior to contact with adhesive
23
~7~
applying roller 362. This roller is partially submerged
in a tank of pressure sensitive adhesive emulsion 364
which can be of a particular colour to colour code the
edge of a file folder as previously described. The doctor
blade 366 is above the level of emulsion and can be
adjusted to accurately vary the amount of adhesive applied
to the lower surface of a high tensile strength film.
After the adhesive emulsion has been applied~ the film is
passed over a number of guides or rollers 368 which are
contained within the heated channel plenum generally
defined by wall members 371 and ~72. Within this channel
plenum a heat distribution conduit generally designated as
373 is provided which allows hot air to be circulated
about the Film to which the adhesive has been applied.
The film after the adhesive has been dried is brought into
contact with the lower surface of the paper stock 300
adjacent the two pressure xollers 340 and 341.
The alignment roller generally indicated as 330
is shown in greater detail Figure 19. The free end of the
roller generally indicated as 331 is the portion visible
in Figure 18. This alignment roller includes a rotatable
barrel portion 332 secured by a pivot connection 333 to
the support bracket 335. Thus the barrel 332 is freely
rotatable and the axis of the barrel can be moved in the
direction of arrow 336 by adjusting of the set screw 33`/.
The high tensile strengh film is snuggly retained between
the sholders 338 and 339 whereby adjusting of the barrel
can vary the position of the film relative to the paper
web stock. As previously mentioned, the paper web stock
is accurately aligned and therefore the simple manual
adjustment of the alignment roller 339 is sufficient to
accurately place the high tensile strength film adjacent
the edge of the paper web stock.
It has been ~ound that the product method and
24
~ ~7~S5
apparatus as described with respect to Figures 13 tn~ough
19 is preferred. Because the high tensile strength filrn
is very thin, it is much easier to handle when secured on
the paper web stock and problems such as creasing or
folding of the film during application to the paper web
stock are reduced.
Paper web stock is very susceptable to wear and
separation of the individual layers thereof which
substantially weakens the overall strength of the web
stock. This problem is particularly acute at areas of
high stress which are subject to damage such as the
portion of the file folder which extends beyond the panels
of the folder to present a surface to which labels can be
applied for identifying of the file folder. As such, the
label identifying portion is prone to wear and often will
tear from the body of the -folder. By applying a high
tensile strength film either side of the paper substrate,
and in a manner to bridge the transition between the
reinforced edge and the body of the file folder, the
tendency of the paper stock to separate is reduced as the
high tensile strength film reinforces the area and limits
the separation of the individual layers. By providing a
film of substantially greater width than the label
extending portion and securing the filrn in a manner such
that the film is secured to the web stock interior to the
label extending portion a distance approximately at least
equal to the label extending portion, it has been found
that the tendency of the edge of the panel to tear from
the folder is reduced as the high tensile strength film
provides a means for distributing the force, which is
locally applied to the label extending portion, to a
larger area of the file folder. Therefore edges of file
folders prone to damage can be reinforced in the manner
described to significantly increase the effective life of
7~
the file folder or substrate.
Although various preferred embodiments of the
present invention have been described herein in detail, it
will be appreciated by those skilled in the art, that
variations may be made thereto without departing from the
spirit of the invention or the scope of the appended
claims.
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26
