US2571460A - Bag closing machine - Google Patents

Description

1951 F. F. LINDSTAEDT ET AL 2,571,460

BAG CLOSING MACHINE Filed Feb. 2, 1946 2 Sheets-Sheet l [N V EN TORS Fran k E L/nasfae d7 C/mr/ e s Fis Cher ATTORNEY 1951 F. F. LINDSTAEDT ET AL 2,571,460

BAG CLOSING MACHINE Filed Feb. 2, 1946 2 Sheets-Sheet 2 V INVENTORS Frank E Lindsf'aed-f' BY Char/e s Fischer ATTORNE. Y

Patented Oct. 16, 1951 2,571,460 BAG cIIosING MACHINE Frank F. Lindstaedt, San Anselmo, and Charles Fischer, Corte Madero, Calif.

Application February 2, 1946, Serial No. 645,044

3 Claims.

The present invention relates to improvements in bag closing machines, and has particular reference to a machine for folding and sealing waxed paper bags, although the principles involved may be applied to other bags, particularly cellophane bags made of synthetic material.

The bags under consideration are of the fiat type, such as are commonly used for potato chips and similar articles of food.

Bags of this type have no flat bottom and cannot be easily carried through a machine for the various closing operations in upright position.

It is proposed, therefore, in the present invention, to feed the bags to the machine in an inclined position and to guide the bags through the machine gradually changing to horizontal position, with a neck portion of each bag confined between two endless belts, the filled body portions advancing on one side of the belts and the ends on the other side of the belts.

It is further proposed to perform all the operations incident to the closing of the bag on the projecting end on one side of the belts in continuous succession, whereby the machine is rendered completely automatic and is made to handle bags at great speed, with a present capacity of approximately two hundred and forty bags per minute.

It is still further proposed to provide a special feed means for the machine whereby the bags may be fed by the mere dropping in promiscuous order, and which is also adapted for'feeding bags of different sizes.

Bags of the type under consideration are usually manufactured with serrated edges at the open end, one edge projecting somewhat beyond the other to facilitate opening of the bags for filling operations.

For the purposes of our machine and for effecting a perfect seal, it is desirable that the edges be cut to uniform, straight lines, and it is proposed in the present invention to provide a novel cutting means to cut the edges to size before the beginning of the folding operation.

It is further intended to provide for a double fold of the end edges of the bags, the two folds being made in two successive operations.

Waxed paper bags have been sealed heretofore, by utilizing the wax as a sealing medium, under the influence of heat. But better results are obtained by applying a special sealing medium,

such as plastic wax, and it is proposed to pro vide means, in the continuous operation of the machine, for temporarily unfolding the folds previously made and for applying a special sealing medium to one of the. contacting faces, in the presence of heat.

And finally, it is,proposed to effect a rapid cooling of the sealed bags, and still in the presence of sufficient heat to keep the wax from becoming sticky and from interfering with the perfect operation of the machine.

Further objects and advantages of our invention will appear as the specification proceeds, and the novel and interesting features of our bag closing machine will be fully defined in the claims attached hereto.

The preferred form of our invention is illustrated in the accompanying drawings, forming part of this application, in which:

Figures 1A and 1B show a plan view of our bag closing machine, Figure 1B being a continuation of Figure 1A, and an inclined conveying means being shown as viewed perpendicularly;

Figure 2, a transverse section taken along line 2-2 of Figure 1A;

Figure 3, a rear view of a portion of our machine, certain parts being shown in section;

Figure 4, a section taken along line 4-4 of Figure 3;

Figure 5, an enlarged rear view of part of the folding and sealing means, with a cover plate removed;

Figure 6, a plan view of the parts shown in Figure 5; and

Figure 7, a fragmentary cross-section taken along line '!1 of Figure 3.

While we have shown only the preferred form of our invention, we wish to have it understood that various changes or modifications may be.

made within the scope of the claims hereto attached, without departing from the spirit of the invention.

Referring to the drawing in detail, our machine comprises, in its principal features:

A pair of endless belts l arranged in superimposed relation so as to present confronting stretches 2 between which the neck of each bag is gripped and advanced, with the main body portion of the bag on one side of the belts and a short end of the bag projecting on the other side of the belts;

Means generally indicated at 3 for feeding the bags to the belts;

Means shown at 5 for trimming the projecting ends of the bags;

Means shown at 6 for folding the end of each b Means shown at i for adding a second fold to the end of the bag;

Means shown at 8 for unfolding the two folds, for applying a strip of glue to the bag material at the fold in the presence of heat, and for refolding the folds upon the glue, and

Means indicated at 9 for cooling the folds in the presence of moderate heat.

The two belts I are narrow so as to engage only a small portion of the neck of each bag, and are mounted on suitable grooved pulleys l0. They are preferably V-shaped in cross-section, and their confronting stretches run in guide grooves IIJ'.

Suitable means (not shown) are provided for tensionin'g the belts so that the flat confronting faces grip the bags with suflicient friction for advancing the same. They both operate, by means to be described later, at the same surface speed. Means are provided, as at H to apply a graphite lubricant to the belts.

The bags, indicated at A, are fed to the belts in inclined position by the means illustrated at 3, which is intended for feeding filled bags of two or more different sizes.

For feeding the smaller size of bag, we use an inclined feedway of considerable length, comprising a channel-like lower section H (see Figure 2) adapted to receive the filled portion of the bag, and a flat upper section |2 slightly setoif with respect to the lower section and adapted to have the upper portion of the bag ride there- The bottom of the channel is formed by a belt |3 running over a pair of cylindrical pulleys l4 and supporting the lower side of the filled portion of the bag for advancing the latter when the belt is moved.

With small bags, the weight of the bag is not always sufiicient to insure positive advance of the bag at belt speed, and we, therefore, provide a second belt l5 on the lower channel wall to bear against and advance the bottom end of the bag. This belt I5 is trained over pulleys l5.

For advancing larger bags, we provide a second channel or trough |6 adjacent the lower end of the first channel, this trough having a third belt adapted to have the filled portion of the larger bags rest thereon and a ledge |8 against which the bottom end of the bag rides. The

larger bag, thus resting on the belt bridges the channel II for the shorter bag and has its upper end ride on the flat upper section l2.

We have found from actual experience that the larger bag is sufiiciently heavy for advancing by a single belt. The belt I1 is trained over the pulleys |4, its upper stretch being raised to the desired elevation by rollers l1 and being bent into the desired plane by deflectors IT".

The two belts l5 and H are mounted on an adjustable frame structure 19 whereby the exact distance of these belts from the upper section |2 may be adjusted to insure proper overlap of the open end of the bag over section l2 for feeding between the belts. For the purposes of adjustment, we provide brackets 20 secured to the frame structure l9 and slidable on the table 2|, the brackets being secured to the table by means of set screws 22 passing through slots 23.

As the bags approach the belts l, the overlapping ends are flattened by means of a rod 26 and are fed underneath two short endless belts 21 trained over a conical pulley 21 and the pulley H). The latter belts cooperate with a flat section 28 of the main table 2| in compressing the two thicknesses of the upper end of the bag and in feeding said upper end between the two main belts It should be noted that all the belts thus far discussed, namely the belts I, l3, l5, l1 and 21 4 run at the same surface speed so that each bag runs smoothly through the entire machine.

The feedway is supported on suitable legs 3!) reinforced by cross-members 3|.

After the neck of the bag has been gripped between the belts for further advance, its projecting end approaches the trimming means 5. The end is supported on a horizontal plate 35 (see Figure 4), and is urged upon the plate by a fiat spring 36, the forward end of which is slotted, as at 31, to admit the rotary saw 38, the lower portion of which extends for a short distance into a kerf 39, so as to trim off the extreme end of the bag.

The saw 38 is in the form of a small disc and has hack saw teeth in the circumference thereof. The blade is very thin, and the kerf 39 is just wide enough to accommodate the teeth of the saw. We find that, due to this arrangement, the saw will perform its function practically indefinitely, without requiring any attention. It is driven by an independent motor 4| through a belt 4|, as shown in Figure 4, and the trimmings are guided into a box 49.

After the end of the bag has thus been trimmed and squared, it enters the folding means indicated at 6 and The folding means comprises in its principal features, a mandrel 45, and two plow shares or mold boards 46 and 4'! cooperating therewith. The mandrel is in the form of a thin metal strip secured upon a section 48 of the main frame structure adjacent the belts and in the horizontal plane of the contact face of the lower belt, so as to form a continuation of the plate 35.

The mandrel comprises two sections 49 and 50, the former being somewhat wider than the latter. The two plow shares 46 and 41 are secured upon a removable plate 5| adapted for fastening upon an upper frame section 52 by means of two screws 53, the plate being guided into its proper position by means of two pins 54 adapted to be received in corresponding holes in the plate. The latter has two handles 55 by means of which it may be conveniently manipulated for attachment and removal.

The first plow share 46 cooperates with the first mandrel 49 in throwing the first fold. The plow share is shown in cross-section in Figure 7 and comprises a plate 56 overlying the mandrel and curved around the edge of the mandrel and underneath the same so as to bend or fold a narrow strip of the projecting bag end underneath the mandrel.

At the forward end of the first mandrel section is provided an escape slot 51 through which the lower fold is allowed to pass upon the upper face of the second mandrel section 55, the fold being guided by a lip '58 at the rear end of the second mandrel. A leaf spring 58 cooperates with the lip in creasing the first fold.

As the folded end passes over the second mandrel section 50, which is narrower than the first section by the width of the first fold, it is again folded by the second plow share 41 in the manner previously described in connection with the first plow share.

Upon leaving the second mandrel section, the two folds, which are now underneath the mandrel, pass over "an anvil 60 which cooperates with a second leaf spring 6| in creasing the second fold.

It should be noted in this connection that the trimming means shown at 5 bears a definite relation to the other elements of the machine and particularly" to the-folding means. One of'its objects is, as previously stated, to eliminate-thesaura-ted edge of the bag commonly used in these operations: But it would be-just asnecessary if a previously squared bag-were used, for thefollowing reasons.

Where thebags are used for accommodating potato chips, it is a fact, that although the same weight of chips be used, theexpansionof the bags varies with the shape of the chips, which again causes variations inthe overall length of the bags; For-varying shapes of chips the overall length of the bag may vary as much as A of an inch, and it is essential, of course, that when the bags reach the folding means, the. projecting ends be cut to a common standard. If they are too long, they would not enterthe mold board, and if they are too short, they would not form a satisfactory fold.

Furthermore, it frequently happens that during the feeding and conveying operations the two sheets of the bag shift with respect to one another with the result that one' sheet would project beyond the otherwhen' the bag reaches the folding means, again with unsatisfactory results.

And. finally, the projecting end edges should not only be cut to a uniform standard, but the standard must bear a definite relation to the folding means, As has been pointed out, the second mandrel section is narrower than the first section by the width of the. first fold and it is necessary, therefore, in order to. prevent binding at the entrance into the second. folding means, that the projecting end be first sized to make the first fold correspond in width to the difference in width between the first and second mandrel sections.

The mandrel thereupon continues in the same plane to terminate into a third section 62 which is still narrower than the second section, and is in the form of a thin strip substantially the width of the folds. At this time the two folds are underneath the mandrel and the body portion of the end of the bag rides on top of the mandrel.

The third mandrel section guides the end of the bag over the glue container 63, which is filled to a desirable height, with a suitable adhesive, such as plastic wax. This container has a narrow glue-applying wheel 64 revolvable therein, and this wheel is rotated, by means later described, at the same surface speed as that of the bag advancing belts l. The wheel is positioned in 'alinement with the third section of the mandrel as thus far described, and is intended to apply a strip of glue to the undersurface of the body portion of the bag end.

For this purpose, it is necessary to separate the two folds from the body portion while the ba passes the glueing wheel. This is accomplished by bending or twisting the mandrel, the first portion of which is horizontal, into vertical position and away from the belts I so as to pass around the wheel, as shown in Figure 6 and by re-bending it into horizontal position after it has passed the wheel. This third mandrel section thus bends the two folds previously formed away from the body portion of the bag end and guides the two folds around the wheel in substantially vertical position while the wheel applies a strip of glue to the underface of the body portion of the bag end. A leaf spring 65 presses the body portion of the bag end upon the glue wheel, and is preferably split to bear on the bag end on opposite sides of the wheel.

After the bag end has passed the glueing wheel.

the mandrel section bends back into horizontal position for a short distance and a third plow share 66 cooperates with the mandrel section in again folding the two folds upon the body sec!v tion of the bag end, the third plow share risinginto the plane of the mandrel at the forward endof'the'latter, as at 6.1, where the leaf spring 68 cooperates with it in pressing the body portion with its strip of' adhesive upon the folds.

During the foldingprocess the bags are sub-1 jected to moderate heat by the electric heater 69 disposed underneath themandrel. The glue container is subjected to more intense heat: by the twoheaters 10- di'sposed' on opposite ends of the container.

Theheat at the mandrel and the plow shares isapplied to prevent the bags from sticking: or adhering to the metal surfaces. In case any trouble should develop at the-plow shares duringthe operation of the machine, the plate 51 may be easily removed to render all the parts accessible forcleaning.

After the glue has been applied, the bag ad vancesto the cooling station indicated at 9. This. station comprises a plurality of spaced anvils H having guide lips 12 and fiat sections 13 disposed in the plane of the mandrel and having leaf springs 14 cooperating therewith in pressing the folded bag ends upon the anvils.

This process is carried out in the presence of moderate heat, an electric heater l5 being arranged underneath the anvils and spaced there!- from. This heat prevents the bags from stick.- ing, while the leaf springs 14 serve to conduct the heat away fromthe bag ends.

Substantially at the glue container, the table 2| gradually curves away from the inclined position shown in Figure 2 into a horizontal plane, and a series of belts 18 are provided for the final advance of the bags and for discharge of the sealed bags upon a transverse conveyor 11.

Any suitable drive mechanism may be arranged for driving the different elements at the desired speed. In the arrangement shown, the reduction gearing in housing is actuated by a motor (not shown) through a pulley 8|.

The reduction gearing drives, through belt 82, the glueing wheel 64 in the glue container 63. It also drives, through chain 83, a shaft (not shown) underneath the shaft 84, which drives the shaft 84 through gearing 85, and also chains 86 and 81.

Shaft 84 drives the pulleys ID on which the main belts I are mounted. Chain 86 operates shaft 88 on which the pulleys 89 for the conveyor belts 16 are mounted.

Chain 8! drives shaft 90, which, through suitable gearing (not shown) drives the pulley IQ for the belts l3 and H. Shaft 90 further drives, through chain 9|, a shaft 92 which is connected, through gearing not shown, for driving pulley l5 and belt 15.

In operation, the bags, which have been previously filled and weighed, are deposited by the operator upon the feedways in any order desired, taking care that the smaller bags ride on the belts l3 and I5, while the larger ones ride on the belt l'l.

They may be fed promiscuously, and the machine, as at present operated, keeps two operators busy at the feeding end. As the bags advance, with their upper ends on the plate l2, the rod 26 flattens the upper ends and then the belts 2'! feed the ends between the belts l.

The bags then advance in continuous procession to be trimmed and squared at the station 5, folded and double folded at G and'l, glued at 8 and finally cooled at 9.

- The glueing operation includes the partial unfolding, applying of the glue, and the re-folding as herein described. The heat applied at the different stations prevents the bags from sticking to the metallic parts of the machine.

' We claim:

1. In a bag closing machine, a pair of belts having confronting stretches for advancing a bag therebetween with an end portion of the bag projecting beyond the belts, a platform adjacent the belts adapted to have the projecting end ride thereon and having a longitudinal kerf therein, a leaf spring overlying the platform and adapted to urge the bag end upon the platform and having a slot registering with the kerf, and a rotary saw mounted over the platform and engaging in the, slot and in the kerf for trimming the bag end as the latter advances.

'2. In a bag closing machine, a pair of belts having confronting stretches for advancing a bag therebetween with an end portion of the bag projecting beyond the belts, a platform adjacent the belts adapted to have the projecting end ride thereon and having a longitudinal kerf therein, a leaf spring overlying the platform and adaptedto' urge the bag end upon the platform and having a slot registering with the kerf, and a rotary saw mounted over the platform and engaging in' the slot and in the kerf for trimming the bag end as the latter advances, the saw having hack saw teeth in the circumference thereof and the kerf being just wide enough to accommodate the said teeth.

3. In a machine of the character described, means for cooling the sealed end of a bag, comprising a series of alined anvils arranged in longitudinally spaced relation and having flat section and downwardly curved guide lips, means for guiding the sealed end of the bag to pass over the anvils, and a leaf spring cooperating with each anvil in urging the bag end upon the same and operable to serve as a means for conducting heat away from the sealed end.

FRANK F. LINDSTAEDT.

CHARLES FISCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED- STATES PATENTS Number Name Date 1,090,499 Poler Mar. 17, 1914 1,374,593 Lundin Apr. 12, 1921 1,919,175 Smith July 18, 1933 2,015,507 Arnold et a1. Sept. 24, 1935 2,018,806 Richard Oct. 29, 1935 2,018,807 Richard Oct. 29, 1935 2,070,822 Beardsley et a1 Feb. 16, 1937 2,245,063 Allen June 10, 1941 2,253,036 Kimple et a1. Aug. 19, 1941 2,272,323 Lawrence Feb. 10, 1942 2,309,760 First Feb. 2, 1943 FOREIGN PATENTS Number Country Date 93,610 Switzerland May 17, 1920

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