Square Bottom Paper Bag.
Year: 1897

page_text: Date of Application, 28th Sept., 1897-Accepted, 20th Nov., 1897.
COMPLETE SPECIFICATION.
Square Bottom Paper Bag.
I, DANIEL APPEL, of Holyoke Place, City of Cleveland, State of Ohio, United
States of America, Inventor, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in the following statement:-
My invention relates to Self-Opening Square Bottom Paper Bags, and the inven-
tion consists in a paper bag having a temporary square bottom formed on lines
that vanish when the bag is filled and the bottom thereby developed to its full
size, and in which the plicated sides are folded at the bottom transversely to the
plies and at some distance inward from their edge, so that when the bag is opened
by a dip of air the plicated sides will bulge out and develop diagonal braces which
will keep the bag distended from bottom to top and make it especially convenient
for filling, substantially as shown and described and particularly pointed out in the
claims.
In the accompanying drawings, Fig. 1 is a plain side elevation of a section of
paper tube or blank from which the bag is made.
Fig. 2 is a perspective view of the bag, with the near edges cut away longi-
tudinally and the bottom shown as it may appear in the process of folding, and
showing the relations of the plies and sides at this stage of the process.
Fig. 3 is a perspective view of the bottom of a bag looking inside and serving
especially to show the inside folds as well as the recess in the bottom and plicated
side, the body of the bag being removed to afford this view.
Fig. 4 is a perspective view of the bottom of the bag showing how the side plies
are folded and turned over the short lap of the bottom as the bottom is being
produced, and also the transverse fold of the plies in the recess back from the edge
of the bag.
Figs. 5 and 6 are perspective elevations of a semi-distended or opened bag, and
Fig. 7 a plan view thereof, illustrating the perfect parallelism of the sides in the
opened bag.
Fig. 8 is a perspective view, and Fig. 9 is a plain broad side elevation of a bag
in a fully opened condition preparatory to being filled, and illustrating not only
the parallelism on its sides but also the primary and the induced brace lines
proceeding out of the bottom and serving to maintain this position and keep the
bag from collapsing.
Fig. 10 is a perspective view of a finished bag folded as for shipping.
Fig. 11 is a perspective view of the bag as it appears when filled. In this view
it will be seen that the temporary bottom lines shown in the other figures have all
disappeared, and that the filled in material has developed the bottom on entirely,
new lines parallel with its sides.
Fig. 12 is a perspective view of the bottom of the bag when it is developed on
the new or filled lines seen in Fig. 11.
Fig. 13 is a perspective view of a bag tube having its bottom stock unfolded to
show the lines of fold.

page_text: Fig. 14 is a perspective view of the bag showing the proportions of the temporary
and finished bottoms as hereinafter described.
The bottom B of the bag as thus .shown has several novel features of construc-
tion. Thus, for example, as seen in the matter of outlines of the bottom, Figs. 5, 6,
and 7, where all the boundary lines,. 22, and 4, 4, of the bottom as originally
developed are only temporary lines and compass, say about, fourfifths of the area
of the full bottom when the bag is filled. These lines, 2, 2, and 4, 4, are the
manufactured lines, which define the outline of the bottom as it enters the hands
of the consumer, but the said lines vanish and are merged in the bottom on all
four sides when the material which fills the bag develops the bottom on its true
lines and rectangular with the square of the body of the bag, as appears in Figs. 11
and 12, and which is the bottom proper of the completed bag.
This partial or unfinished development of the bottom in the manufacture of the
bag, is, however, purposely contemplated in order that other points of material
advantage in the manufacture and opening of the bag may be attained. Having
reference now to the latter advantages, attention is called to Figs. 8 and 9, where
the bag is shown as fully opened for filling. Here it will be seen that the
corners, a, a, from top to bottom are perfectly parallel, and all four sides are fully
distended while the bag is in condition to stand alone box like on its flat bottom B.
It will also be seen that the plicated sides are abnormally bulged or distended at 5,
and that two divergent lines meet at this point, the lower one, b; b, extending
diagonally over the exposed surface of the ply and apparently losing itself behind
the edge of the bag, Fig. 8, and the other line, c, c, extending from point 5,
substantially to the top of the bag where it is gradually lost. Now these lines
are not distinct marks on the bag but represent rather the swells which are induced
and rendered possible by the distinct angle lines, E, E, lower down and which
converge from the transverse fold or rib 7 on each plicated side to the centre line
of the plies and for the time being are the true but temporary boundary lines of
the bottom B at these sides.
Thus are defined the means on which I rely to hold the bag fully open after a
dip of air, and the induced swells of the sides having their focal point at 5
operate as stiff braces which not only spread the sides of the bag to its full
rectangular outlines as seen in Fig. 8, but hold the sides in that position and
relation preparatory to filling and without other means to keep the bag from
collapsing.
Referring now to Fig. 9, we have the distinct crease lines, E, E, which are
permanent fold lines of the plies into the bottom, and by reason of their starting
from the ends of the transverse bottom rib 7, which is back from the outer edges
of the bag by about one-fourth the depth of the plies, it follows when the bag is
dipped and thrown open that the said lines, E, E, are carried out at their top to
the diagonal position seen in dotted lines, E, E, Eig. 9. Then because these
lines, E, E, are shortened by being caught back in the recess by the ends of rib 7
there is naturally induced the secondary line, b, b, higher up because here the
stock is free to come out to what will ultimately become the bottom fold line of the
filled bag. These secondary lines are supported by the primary ones E, E, forming
a bracing angle and then there is that further upwardly extending swell which
carries its laterally bracing effect clear into the open mouth of the bag. Thus by
retiring the side rib 7 within the sides as shown, and limiting the bottom to this
inner boundary to begin with, I utilize the plies of the bag from bottom to top to
hold the bag open for filling, as seen in Figs. 8 and 9.
When the bag is thus opened, the rib 7 remains as a present factor in the
structure, and that the broad sides of the bag also are contracted thereby at the
bottom on both sides to the depth of the rib. in the recess, and the bag shows a
somewhat rounded surface above the transverse crease lines, h, h, which
are coincident with the ends of rib 7.. These lines, h, h, and the ribs 7.
at the plicated sides, define the outline of the temporary, bottom hereinbefore
described, and both said lines and ribs disappear and are taken up in the

page_text: bottom B, and wholly new bottom lines form on all four sides, as indicated by k, k,
and n, n, Fig. 11, when this bag is being filled, and which then become the edges
of the finished bag for use.
Several details of construction enter into the production of the bag in addition
to those already described which are of importance. Thus, referring to Fig. 3,
it will be seen that on each plicated side of the bag there is a triangular fold 8,
which has its base in the transverse rib, 7. This triangle is in fact a double
triangle, having the medium fold line, c, c, of the plies through its centre and being
formed one half from each of the side plies. The counterpart thereof is seen in
the triangle 9, Fig. 8, which works into both the bottom and side of the bag when
the bag is opened. The opposite sides 10 and 12 of the plies corresponding to the
triangle 8 are folded into the bottom with the laps 13 and 14 over triangle 8
after the manner seen in Fig. 2, where the edge of the bag is cut away to clearly
disclose these parts. In making this fold at the junction of the plies and angles
described a short triangular turn is given to the stock where the plies meet, as
seen at 15, Figs. 4 and 13, wherely the inner ply 10 is turned down with short
lap 13 and the outer ply 12 is brought across lap 13 through the slit 16, and folded
down with long lap 14 on top. This brings the short lap 13 between the two inside
plies in the bottom, while the long lap 14 is folded and pasted over all on the
opposite side of the bottom as seen in Figs. 10 and 12.
The diagonal slits 16 are made just inside of the inner or medium lines, c, c, of
the plies, and the material at the outer side thereof is turned under the overlapping
triangle 15, whereby the parts are lapped across each other and thereby contribute
materially to the strengthening of the bottom and prevent so-called pin holes for
escaping material. Between these slits a dove-tail tongue 17 is developed which
forms a part of the short lap, 13, and is projected to the opposite side of the
bottom from lap 14 when the bottom is folded as shown.
The bag is pasted in the blank either when it is open as seen in Fig. 1 or at a
subsequent period in the manufacture, and the paste is applied to the lips or laps
of the bottom along the edges as shown in Fig. 4.
It will be noticed that in folding the bottom the tongue 17 extends beneath and
is pasted to the under side of the lap 14, while lap 14 pastes on the opposite side
of the bottom over or upon the short side or lap 12, and the stock outside of the
slits 16 pastes under the ply 12.
Fig. 14 shows the sizes of the temporary and the finished bottoms, respectively,
by contrast on the projected lines 20 and 25. Here it will be clearly seen that the
manufactured bottom is very materially contracted as compared with the ultimate
finished and full bottom of the filled bag, and this contraction is the result of the
retired ribs 7 which draw the broad sides in at the bottom to the depth of the ribs
in the bottom. This contraction of the bottom, furthermore, induces brace lines
on the broad side of the bag corresponding to the induced braces on the plicated
sides and extending up over said broad sides in such way as to spread and hold
them to the full flat, parallel forms, shown in Figs. 8 and 9. As already stated,
the lines 20 totally disappear and are flattened out in the bottom when the bag is
filled and developed to lines 25.
A further feature of improvement is the creasing of the corners 30 of the bag,
at an angle to the sides, as seen in Fig. 10. This crease line runs from the
temporary bottom corners on line 20, to the points which form the corners or angles
of the lines 25, and not only helps to fix and determine those corners when the
bottom develops in filling, but prevents any fine or granulated material creeping
into those corners and embarassing the symmetrical development of the corners
of the bottom.
'
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:
:-
1. A paper bag substantially as described having a rib transversely of its sido

page_text: plies in the bottom of the bag inward from the edge thereof and diagonal brace
lines from the ends of this rib to the centre of the plies, substantially as described.
2. The bag described, having a rib at its bottom on each plicated side back
from the edge proper of the bottom and shorter than the said edge, and converging
brace lines between the ends of said ribs terminating in the centre of the plies,
substantially as described.
3. A paper bag having temporary folding bottom lines on its four sides over
which the four sides of the bag spread and unfold the bottom on new lines parallel
with the square of the bag when the bag is filled, substantially as described.
4. A square bottom bag having the broad sides of the bottom folded one across
the other in opposite directions and one of the side plies at each plicated side
folded in between said broad sides, substantially as described.
5. The bag bottom described having its shorter lap at the bottom slitted from
the intersection of the side plies, and the said side plies turned to a substantially
triangular shape at their intersection and folded back through said slits, and the
longer lap folded and pasted over all, substantially as described.
6. In paper bags, a bag having a square bottom formed on temporary lines across
the broad sides of the bottom and the plies on both sides folded to form ribs
returned about one fourth the depth of the plies from the edge of the bag, whereby
temporary unfolding lines are produced on all sides of the bag, substantially as
described.
7. A paper bag having a temporary flat square bottom of less dimensions than
the square of the bag in cross section, and transverse ribs in the plicated sides
contracting the four sides of the bottom on temporary lines, substantially as
described.
8. In square bottom paper bags, a bag having a temporarily formed bottom of
less size than the full bag in cross section, and having the corners of said temporary
bottom creased at an angle to its sides, whereby the opening of the bottom on full
lines is facilitated, substantially as described.
Doted thie 31st day of August 1897.
DAY, DAVIES & HUNT,
Chartered Patent Agents,
321, High Holborn, London, W.C., Agents for the Applicant.