US2193756A - Method of making bags - Google Patents

Description

March 12, 1940. T, M, VERY 2,193,756

METHOD OF" MAKING BAGS Original Filed May 12, 1938 2 SheetsSheet 1 2%: fines-RY March 12, T M AVERY v 2,193,756

METHOD OF MAKING BAGS Original Filed May 12, 1938 2 Sheets-Sheet? grwmto b z 7kua/f 144R)? Patented Mar. 12, 1940 PATENT OFFICE 2.19s,75s METHOD OF MAKINGnAea True M. Avery, Glensllalls, i58

assigfror" to Union Bag & Paper Corporatiem'llirdsonfalls, N. Y., a corporation of New Jersey Original application May 12, 195:8, Serial No.

207,620. Divided and this application October 14, 1938, Serial N0. 235,073

'- 4 Claims.

The present invention relates to improvements in the manufacture of bags of thekind composed of paper, Cellophane or other flexible material ,and adapted to contain goods or commodities of various kinds, and it relates more particularly to the manufacture of bags of the so-called satchel bottom type, wherein the bottom is closed by flaps formed by folding inwardly the edges and then folding and pasting portions of the sides of the bag onto the first folded flaps.

In making bags of this type, it has been the common practice heretofore to form slits in the side portions of the bag which are to constitute the bottom closing flaps to afford increased areas fortthepasting of these flaps ,down upon the previously foldedflaps, but such slitting of the bag presents the disadvantages that the flaps have a. tendency to tear beyond the slits when the end-of. the bag tube is opened during the process of forming the bag bottom, and in the finished bag the weight of the material therein often causes the bottom flaps to tear beyondthe slits,

resulting in leakage of the contents of the bag.

vThe primary object of. the present invention is 25 to provide a novel and improved method of making a bag which avoids such disadvantages, it

providing the bottom closing flaps of the bag with tabs or ears which project therefrom and afford increased or supplemental areas for the pasting and securing of such flaps to the previously folded bottom flaps, thereby serving to distribute the loadof the contents of the bag over a larger area of the bottom thereof and thus strengthening and avoiding tearing of the bag bottom, these tabs or ears being formed prior to-the folding of the bottom flaps and avoiding any. tendency of the flap forming portions of the bag to tear during.

the bottom forming operation as occurs when the flap forming portions are slitted, as heretofore.

4,0 These featureszof the presentinvention are particularly advantageous when the bags are made I Fig. 2 is a view similar to Fig. 1 but showing one edge of the strip folded; Fig. 3 shows the strip completely folded to form a bag tube;

Fig. 4 shows a bag length cut from the bag tube;

Fig. 5 shows an end of the tubular bag length after the same has been opened'to fold the side edges inwardly and thus form two of the bottom closing flaps;

Fig. 6' is a view similar to Fig. 5 but showing the closing flap at one side of the bag folded onto the previously folded bottom flaps;

Fig. 7 is a view of the completed bag, partlyin section and partly broken away, the closing flap at thefotherside of the bag being shown folded and pasted onto thepreviously folded flaps;

Fig. 8 is a detail section taken on the line 88 in Fig. 5; I Fig. 9 is a detail section taken on the line 9-9 in Fig. 6; and

Fig. 10 is a detail section taken on the line i0l0 in Fig. 7. I

The method according to the present invention is applicable generally to the manufacture of bags k having either a single wall or thickness or two or more walls or thicknesses, it being shown'for example in the present instance as appliedto the manufacture of .a bag of the so-called duplex type'having two walls or thicknesses.

In carrying out the invention as shown in the present instance, the bags may-be formed from a strip composed of two sheets or webs I. and

2 of paper, Cellophane" ,orother suitable flexible .35 material which are placed one upon the other in offset or staggered relation asv shown in Fig. 1. Before superposing, the sheets transverse rows of spots of adhesive 3 and 4 are applied to one of the sheets adjacent to the lines, indicated at 5, 40 on which the bag tube is tobe severed in forming the bag lengths',these spots of adhesive serving. to' unite ,the sheets. in'the regions of the-"finished bag bottom and fthebag mouthl, Each section of the strip is formed, adjacent to the line, of

severance 5 w ith apair Tof tabs orears iyvhich are preferably semi-circular in. form. and may be produced by punching 'semiicirciil ar cuts through those portions of both" of the" sheets which ad.- join the portions thereof whieh are to form'the finalbottorn clt'isin'gflap, the bases of these semicircularF tabs'or ears lying-on divergent lines "I which "represent" the folded marginaledges of the final bottom closing'flap." The pastespots 3 are so located that certain of these paste spots will lie at the bases of these tabs or ears and will thereby secure together the tabs or ears on the two sheets. The bag strip, while in flat or web form, may also be punched with holes 8 which extend through both sheets and extend to opposite sides of the lines 5 on which the bag tube is severed, a portion of each of these holes forming a thumb hole 9 at the mouth of the bag, and. the other portion of each of each of these holes forming a cutaway portion ID on one of the bottom closing flaps.

The bags may be made rapidly on a bag machine of conventional form having a former to which the bag strip is fed, and having folders for folding the longitudinal edges of the strip inwardly on the line I I as shown in Fig. 2 and for folding the opposite longitudinal margin of the strip inwardly on the line l2 to bring lines of adhesive I3 and I4 previously applied to the sheets I and 2, onto the inwardly folded portions along the opposite margin of the strip, thus forming the strip into a bag tube as shown in Fig. 3, the lines of adhesive l3 and I4 forming the longitudinal seams of the bag. The bag tube thus formed is then severed, on the lines 5, to form a bag section as shown in Fig. 4.

The end of each bag length which is to constitute thebottom of the bag is then opened into the form of a diamond fold, which may be accomplished by the well known bottoming mechanism of a bag machine of conventional type. This "diamond fold is formed by pulling the side of the bag provided with the cutaway portion It) and folding it against the body of the bag along the fold line I5, in consequence of which the edge portions of the bag are drawn inwardly to form the bottom flaps I6. The drawing inwardly of the flaps I6 forms diagonal fold lines I between them and the opposite sides of the bag, and since the fold lines 'I extend across the bases of the tabs or ears 6 which are cut from these portions of the bag strip which form the flaps IS, the tabs or ears 6 will remain unfolded and will project beyond the fold lines I, as shown in Fig. 5.

The portion of the bag bottom provided with the cutaway portion I0 .is then supplied with spots of adhesive l8, and a spot of adhesive I 8 is applied through the cutaway portion II) to this portion of the bag bottom, and spots of adhesive 2| are applied to the tabs or ears 6 and a spot of adhesive 2| is applied between the inner edges of the infolded flaps I6 to the outer portion of the closing flap 22. The extremity of the portion of the bag bottom having the cutaway portion is then folded on the fold line I9 to form a bottom closing flap 2!! which is pasted onto the flaps I6, as shown in Fig. 6, after which flap 22 is folded on the fold line 23 onto the previously folded flaps I6 and as shown in Fig. 7, so that the tabs or cars 6 which overlie portions of the flaps I6 and the flap 20 as well as the closing flap 22 will be securely pasted to the underlying previously folded flaps by the paste spots 2| and 2| thus completing the bag bottom. By applying a spot of paste I8 through the cutaway portion In onto the portion of the flap 20 which is exposed through this cutaway portion, the outer portion of this flap is securely pasted to the underlying flaps I6.

The tabs orv ears 6 provided on the bottom closing flap, when supplied with the paste spots 2| and pressed against the underlying or previously folded flaps l6, securely seal or secure the outer portion of the flap 22 to the flaps I6 and the spot of paste 2| applied to the flap 2 near its apex or extremity securely seals the outer portion of this flap to the previously folded flap 20.

In applying the invention to the manufacture of a duplex bag, as shown in the present instance, the paste spot I8 applied through the cutaway portion Ill to the outer portion of the flap 20 will secure both outer plies of this flap to the flaps I6 since the outermost ply of the flap 20 is secured to the adjacent inner ply thereof by the paste spots 3, and the paste spots 2| and 2|- applied respectively to the tabs or ears 6 and to the outer portion of the flap lying between the inner edges of the flaps I6 will secure both outer plies of the flap 2 to the flaps I6 and 20 respectively, since the outermost ply of the flap 22 is secured to the adjacent inner ply thereof by the paste spots 3.

While the invention is shown applied to the manufacture of a bag of the duplex" type comprising inner and outer walls or plies, obviously the invention is equally applicable to the manufacture of bags having a single wall'or ply which can be made by the same method hereinbefore described but from a single sheet instead of two sheets, in which event the paste spot I8 applied through the cutaway portion III to the flap 20 will directly seal or secure the outer wall or ply of this flap to the flaps I6, and the paste spots 2| and 2| applied respectively to the tabs or ears 6 and between the inner edges of the flaps I6 to the outer portion of the flap 22 will directly seal or secure the outer wall of the flap 22 to the flaps I6 and 20 respectively.

Although the paste spots 2| applied to the tabs and the paste spots 3 between the sheets adjacent to the bases of the tabs in a duplex" bag are preferably relatively small as shown, these paste spots will spread, when pressure is applied incident to the pasting together of the bottom flaps, suificiently to cover ample areas of the tabs to firmly secure them, thereby avoiding objectionable squeezing of excess paste from between the flaps.

By providing the tabs or cars 6 on the bottom closing flap 22, this flap is secured over a larger extent of its area to the previously folded flaps than heretofore, thereby strengthening the bag bottom and distributing the stress of the load in the bag over a larger area of the bag bottom, thus enabling the bag bottom to effectively withstand any tendency to tear under the load, as in bags of the satchel bottom type having slits in their bottom flaps.

Moreover, by providing these tabs or cars instead of slits as heretofore employed, the stress applied in opening the bottom of the bag into a diamond fold during the bottom forming operation will not tear the bag bottom, as fre quently occurs in the manufacture of bags of the satchel bottom type having slltted bottom closing flaps.

The method according to the present invention may be employed to manufacture bags on bag machines of conventional and well known form economically and with the same speed and facility as ordinary bags.

I claim as my invention:

l. The method of making satchel bottom bags which comprises cutting adjacently located tabs and an aperture offset laterally therefrom in a strip of material, forming the strip into a tube and thereby bringing said tabs and aperture into positions on one side of the tube, forming a diamond fold at one end of the tube along fcld lines some of which intersect the bases of said tabs and others of which converge toward said aperture, thereby providing bottom flaps connected by diagonal fold lines and causing-the tabs to project unfolded from the diagonal fold lines of one of the flaps and exposing a portion of the outer ply of the other flap through said aperture, applying adhesive to said tabs and t0 ;;ube on a transverse line adjacent to said tabs and intersecting said aperture, forming a diamond fold at one end of the bag length, thereby folding the edges of the bag length inwardly to form bottom flaps connected by diagonal fold lines two of which extend past the bases of said tabs and two of which fold lines converge toward said aperture, thereby leaving said tabs unfolded and projecting from said fold lines of one of the flaps and exposing a portion of the outer ply of the other flap through said aperture, applying adhesive to said tabs and flaps and to said exposedmortion of said outer ply, and folding said flaps and tabs to adhesively secure them.

3. The method of making bags which comprises forming tabs in a portion of a strip of material which is to form one side of a bag tube, then forming the strip into a tube and thereby bringing said tabs to said side of the tube in positions spaced equidistantly laterally of the longitudinal center thereof, then severing the tube on a transverse line adjacent to but spaced outwardly from said tabs to form abag length, then folding an end of the bag length on lines which substantially intersect the bases of said tabs, thereby forming bottom closing flaps and leaving said tabs unfolded and projecting from the fold lines of one of the flaps, and subsequently applying adhesive to said tabs, and folding said tabs and the flap from which they project onto underlying flaps.

4. The method of making bags which comprises cutting adjacently located substantially semi-circular divergently extending tabs in a strip of material at one side of its longitudinal center, then forming the strip into a tube and thereby bringing said tabs into positions spaced laterally from the longitudinal center of one side ofthe tube, then severing the tube on a transverse line adjacent to but spaced outwardly from said tabs to form a bag length, then foldingan end of the tube to form bottom closing flaps connected by diagonal fold lines some of which substantially intersect the bases of said tabs, thereby causing said tabs to remain unfolded and to project from the fold lines of one of the flaps, and subsequently applying adhesive to said tabs, and folding the flap and the tabs projecting therefrom onto and 'adl esively securing them to underlying flaps.

\ TRUE M. AVERY.

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