US2542170A - Method of adhesively securing valve sleeves to bags - Google Patents

Description

N. E. WEEKS 2,542,170 METHOD OF ADHESIVELY SECURING VALVE S TU BAGS I Feb. 20, 1951 Original Filed Dec. '7, 1946 4 Sheets-Sheet 1 N. E. WEEKS 2,542,170 METHOD OF ADHESIVELY SECURING VALVE SLEEVES T0 BAS Feb. 20, 1951 4 Sheets-Sheet 2 Original Filed Dec. 7, 195% mm J 0 G 3 IIIJSJ m9 Q 0. EEIIILL mv .B 3 MN B. u v E R 1 k Q 4 |u I u n M H L I ||l O Q 3 3 s m w T L P h 1 m w u a M .mim i i ,1 E\ i W F l l. Q I: Q Q l Mt! mm. m E M Q Q Q" Q R Q a. 5 i. W 1 I'l ll o. l i my E 3 u O o 0 II O o villi]; 2 n I Cir llll II... N W O Q m OE N. E. WEEKS Feb. 20, 1951 METHOD OF ADHESIVELY SECURING VALVE SLEEVES T0 BAGS 4 Sheets-Sheet 3 Original Filed Dec. '7, 1946 FIG.6.

FIG.8.

N. E. WEEKS Feb. 20, 1951 IETHOD 0F ADHESIVELY SECURING VALVE SLEEVES 1'0 BAGS Original Filed Dec. 7, 1946 4 Sheets-Sheet Patented Feb. 20, 1951 METHOD OF ADHESIVELY SECURING VALVE SLEEVESTO BAGS Norman E. Weeks, Normandy, Bemis Bro. Bag Company,

corporation of Missouri Original application December 7,

Mo., assignor to St. Louis, Mo., a

1946, Serial No.

714,756. Divided and this application October 9, 1948, Serial No. 53,717

2 Claims.

This invention relates to a method of adhe Among the several objects of the invention may be noted the provision of an improved method of adhesively uniting valve sleeves in bag valves by means of thermoplastic adhesive; the provision of a method of this class adapted to accomplish accurate and effective securement of valve sleeves to bags in minimum time so as to achieve a high production rate of valve bags per operator; and the provision of a method for this purpose which requires no special skill on the part of the operator and which may be readily and apparent and'in part pointed out hereinafter.

The invention accordingly comprises the steps and sequence of steps, and features of manipulation, which will be exemplified in the methods hereinafter described, and the scope of the application of which will be indicated in the following claims.v

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is an exploded view illustrating a bag and valve sleeve in the process of assembly:

Fig. 2 is a perspective illustrating the assembled bag and valve sleeve;

Fig. 3 is a semi-diagrammatic plan viewof an apparatus for carrying out the method of this invention also illustrating the step of uniting the sleeve and bag;

Fig. 4 is a view of a completed valve bag; Fig. 5 isan enlarged detail plan view of the apparatus, certain parts being broken away:

Fig. 6 is a section taken on line 6-6 of Fig. 5;

Fig. 7 is a section taken on line 1-4 of Fig. 5;

and,

Fig. 8 is a side elevation as viewed from the right of Fig. 5. 1

Similar reference characters indicate corresponding parts throughout the several 'views of the drawings.

Referring now particularly to Figs. 1-3, Fig. 1 illustrates a textile fabric bag I and a valve sleeve 3 which are to be adhesively joined by the method of this invention to form a valve bag. At this stage of the process in the manufacture of the valve bag, the mouth 5 of the bag is open.

The sleeve 3 comprises a rectangular paper sheet.

the short sides of which are caused to extend longitudinally with respect to the bag. The sleeve is creased on its longitudinal center line I and has a slit 9 extending inward from its outer edge upon the center line. The sleeve is also prepared-with a transverse stripe of thermoplastic adhesive II by means of which it is to be adhesively secured to the bag.

To form a valve bag, the sleeve 3 is folded upon the crease with adhesive l l on the outside of the folded sleeve. It is then inserted intothe mouth of the bag, being fitted in a corner thereof as illustrated in Fig. 2, with the stripe of adhesive engaging the inside wall of the bag adjacent its mouth and with the slitted portion of the sleeve extending outward. This bag and sleeve assem- 1 bly, hereinafter referred to as the work, is then I fed'through a heated presser unit l3 (Fig. 3) in safely employed. Other objects will be in part Lin "a' direction parallel to the edge of the bag mouth at such a relatively low rateof speed as to permit the adhesive to soften and secure the sleeve to the bag under pressure. It will be noted from Fig. 3 that the aforesaid corner of the bag is introduced first into the presser unit. It will also be noted that once this corner of the bag has been fed through the presser unit there remains a substantial portion of the work, designated X Figs. 2 and 3, in which there is noadhesive to -'be acted upon. Consequently, there is no necessity for feeding this portion of the work through the presser unit at the same relatively low'rate of speed as said corner. In order to clear the bag rapidly from the presser unit once its corner isvsuestherefrom, so that the operator may soon jfee'd another bag and sleeve assembly thereto,

the method of this invention further includes the :step of pulling the bag through the unit at considerably higher speed than the aforesaid rate so as quickly to eject the completed product. Thus, that limited portion of the bag and sleeve assembly wherein adhesive is to be softened is fed through the presser unit slowly enough to permit the adhesive to soften, and the remainder of the bag is pulled rapidly out of the presser unit.

The resultant product, which corresponds to Fig. 2 except that the sleeve 3 is now afilxed in the comer of the bag at its mouth, is subsequently formed into a valved bag illustrated in Fig. 4 by tucking in the sleeve-lined corner to form; a sleeve-lined valve flap. A seam I5 is finally stitched across the mouth of the bag to close it. This forms a valve bag having a valve inlet ll, of which the sleeve liner-forms an inward extension, the bag being adapted to be filled with comminuted or pulverulent material by inserting a filling spout through the valv inlet. When the bag is filled, the pressure of the filling closes the valve and thereby prevents leakage of the filling from the bag. as will be readily understood from the art.

Generally, as stated, the apparatus as shown embodies means for feeding the work through the presser unit I3 at the rate of speed such as to permit the adhesive to soften. This means comprises two sets I9 and 2| of continuously driven draw rolls which are driven at such a speed as to advance the work at the aforesaid rate. Work issuing from the presser unit is subsequently gripped and pulled through the presser unit and ejected therefrom by a set 23 of continuously driven pulling rolls, which are adapted to impart the aforesaid higher speed of travel to the work. As will be made clear, suitable means are provided in the drives for the draw rolls to permit them to rotate faster than their drives during the work pulling operation.

The presser unit I3 comprises a lower fixed heated presser head 25 and an upper heated presser head 26 which is spring-biased into engagement with the lower head. The lower head is fixed upon the end of a supporting arm 21 which extends outward and upward from the base plate 29 of the apparatus. It comprises a channel bar 3| which is secured by screws 33 to the end of arm 21 with the channel opening upward. Disposed within the channel is an electrical resistance strip heating element 35. A layer 31 of suitable heat insulating material, such as asbestos, is disposed between the heating element and the channel. An elongate steel plate 39 is secured byscrews M (Fig. 6) to the channel over the heating element. This plate has a smooth upper surface which forms the lower pressure-receiving surface of the presser unit I3. Current is supplied to the heating element 35 by conductors 43.

The upper presser head 28 is similar to the lower head and comprises a. channel bar 45 fixed upon the lower end of rods 41 with the channel opening downward. Disposed within the channel is an electrical resistance strip heating element 49, a layer of heat insulating material being disposed between the heating element and the channel. An elongate steel plate 53 is secured by screws 55 to the channel over heating element 49. This plate has a smooth lower surface which forms the pressure-applying surface of the presser unit I3. Current is supplied to heating element 49 by'flexible conductors 51.

The upper ends of rods 41 are slidable in apertures in a plate 59 carried by a supporting arm BI extending outward from a pedestal 63 on base plate 29. The rods are biased downward by compression springs 65 reacting between the under surface of the plate 59 and nuts 61 threaded on the rods to bias the upper presser head into engagement with the lower presser head. The bias is adjustable by means of nuts 59 threaded on the ends of rods 41 extending through plate From the above it will be clear that work may be fed between the heated pressure plates 39 and 53, as illustrated in Fig. 3, to soften the springs 65 in accordance with the thickness of the work. The work is fed through the presser unit from right to left as viewed in Fig. 6, and it will be noted that plates 39 and 53 diverge at their right hand ends to form an inlet throat II.

The work is fed between the presser heads by the aforesaid sets I9 and 2| of draw rolls. The set I9 comprises upper and lower spool-shaped rolls I3 and mounted upon upper and lower draw roll shafts I1 and I9, respectively. The

, upper shaft TI is journalled in vertically sliding pedestal.

bearings 8I in the aforesaid pedestal B3 and in another pedestal 83 mounted on base plate 29 and axially spaced from pedestal 63. Bearings 8| are guided for vertical sliding movement in suitable guideways in the pedestals and are biased downward by compression springs 85. Lower shaft I9 is journalled in fixed bearings 81 in the The arrangement is such that the axially spaced knurled flange portions 89 of the upper draw roll I3 are biased into engagement with the axially spaced knurled flange portions 9I of the lower draw roll 15, and the upper draw roll may rise as work is fed through the apparatus in accordance with the thickness of the work. The nip of draw rolls l3 and I5 is adjacent the forward end of inlet throat II of the presser unit and the pass plane of these rolls is substantially coincidental with the mating plane of the pressure surfaces of plates 39 and 63 (Fig. 6).

The set 2| of draw rolls is similar to set I9, comprising upper and lower spool-shaped rolls 93 and 95 mounted upon upper and lower draw roll shafts 91 and 99, respectively. Upper shaft 91 is journalled in vertically sliding bearings IOI, corresponding to bearings 8|, in pedestals 83 and 83. These bearings are biased downward by springs I03 corresponding to the springs 85. Lower shaft 99 is journalled in fixed bearings I95 in the pedestals. Thus, the knurled flange portions III! of the upper draw roll 93 are biased downward into engagement with the knurled flange portions I09 of the lower draw roll 95, and the upper draw roll may rise as work is fed through the apparatus in accordance with the thickness of the work. The nip of draw rolls 93 and 95 is some distance rearward of the exit end of the presser unit and the pass plane thereof is substantially coincidental with the plane of the pressure surfaces of plates 39 and 53. It will be noted that the presser unit is disposed within the recesses of the draw rolls between their flange portions.

Each of the aforesaid draw rolls 13, I5, 93 and 95 is adapted to be driven by its respective shaft through an overrunning clutch in order to permit each draw roll to be rotated faster than its shaft when required. As illustrated particularly in Fig. 6, each of the draw rolls is rotatably mounted upon the end of its shaft. A ratchet I I I is fixed upon each draw roll shaft adjacent the draw roll thereon. Pivotally mounted upon the inside flange portion of each draw roll is a pawl II3 biased into engagement with the respective ratchet by a spring 5 carried by said flange portion. The arrangement of the ratchet and pawl mechanism is such that when the draw rolls are rotated in the forward direction at a speed faster than the speed of their respective shafts, the draw rolls may overrun their shafts, the pawls ratcheting over the ratchet teeth during such overrunning action.

.The set of pulling rolls comprises an'upper knurled roll Ill and a lower knurled roll II9. Upper roll III is fixed upon the end of a shaft I2I journalled for rotation in vertically slidable bearings I23 in pedestals 63 and 83. These bearsuitable guideways in ings are guided for vertical sliding movement in the pedestals and are biased downward by compression springs I25. The lower pulling roll H9 is fixed on the end of a shaft I 21 which is journalled in fixed bearings I29 in the pedestals. The arrangement is such that the upperpulling roll H1 is biased into engagement with the lower pulling roll II9. It will be noted that the upper pulling roll may rise as work is fed through the apparatus in accordance with the thickness of the work. The pulling rolls Ill and H9 are located in such position that the work issuing from between the pressure plates 39 and 53 of the presser unit is picked up in the nip of these rolls and fed outward (to the left as viewed in Fig. 6). Pulling rolls H1 and I I9 are of greater diameter than the draw rolls 13, 15, 93 and 95 and their peripheral speed is greater than that of the draw rolls to pull the work through the apparatus at a higher rate of speed than the rate at which the work is fed forward by the draw rolls.

Suitable driving means is provided for driving the draw roll and the pulling roll shafts. As illustrated in Fig. 3, a motor I3I is coupled through a speed reducer I33 and a belt drive I35 to drive the upper pulling roll shaft I2I ing roll shaft is coupled to drive the lower pulling roll shaft I21 at the same speed by means of intermeshing gears I31 and I39 fixed on the upper and lower shafts III and I21, respectively. The upper pulling roll shaft III is coupled to drive the upper draw roll shaft 11 by a speed-reducing chain and sprocket drive I. The upper draw roll shaft 11 is coupled to drive the upper draw roll shaft 91 at the same speed by means of a chain and sprocket drive I43. The upper draw roll shaft 11 is coupled to drive the lower draw roll shaft 19 at the same speed by means of gears I41 and I49, and the upper draw roll shaft 91 is coupled to drive the lower draw roll shaft 99 at the same speed by gears III and I53.

The apparatus also includes means for guiding the work into the presser unit and into the nip of the set I9 of drawing rolls. This means comprises a table I55 supported upon the base plate 29 of the apparatus with its upper surface substantially coplanar with the mating plane of the pressure plates 39 and 53 and the pass plane of the draw'and pulling rolls. A guide bar I51 is transversely adjustably mounted upon the table. Screws I59 extend upward from the table through slots in slotted fingers I5I on the bar, and the bar is clamped in adjusted position by wing nuts I63 threaded on the screws.

The operation of the apparatus is as follows:

The guide bar I51 is initially adjusted relative to the longitudinal center line of the presser unit I3 so that the distance from the face of the bar to this center line is equal to the distance Y from the outer edge of the valve sleeve 3 to the center line of the stripe I I of adhesive thereon. Current is supplied to heaters 35 and 49 to heat the pressure plates to a temperature sufficient to soften the adhesive consistent with the rate of speed at which the work is fed therebetween. The motor I3I is energized to drive the draw rolls 13, 15, 93 and 95 and pulling rolls Ill and H9 continuously.

The operator inserts the bag and valve sleeve assemblies illustrated in Fig. 2 successively into the inlet throat 1| of the presser unit in the manner shown in Fig. 3, employing the guide bar I51 as a guide for the outer edge of the valve sleeve. The work is inserted into the throat 1| and be- The upper pulltween pressure plates 39 and 53 a sufiicient distance to introduce it into the nip of the draw rolls 13 and 15, whereupon these draw rolls (and subsequently the draw rolls 93 and function to feed the work forward between the plates at a speed equal to the nominal peripheral speed of the draw rolls. With the outer edge of the valve sleeve in engagement with guide bar I51, registration of the stripe II of adhesive between the pressure plates is assured. As the work is fed between the pressure plates, the adhesive is softened by heat and the plates press the walls of the bag and the valve sleeve firmly together to effect adhesive afilxing thereof.

As the forward edge of the work leaves the presser unit, it is caught in the nip of pulling rolls H1 and H9 and the work is pulled through the presser unit at substantially higher speed and delivered from the apparatus to a station where the subsequent operation of tucking in the corner of the bag is performed. During pulling of the work by pulling rolls H1 and H9, draw rolls 13, 15, 93 and 95 are driven by the work in the forward direction at a greater speed than that nominally imparted thereto by their respective drive shafts. During this phase of the operation, the draw rolls overrun their shafts, this being permitted by the pawl-and-ratchet overrunning clutches.

The feature of pulling the work through the presser unit by means of the high-speed pulling rolls is of considerable importance inasmuch as it reduces to a minimum the time required to feed the work through the apparatus. Note that once the corner of the bag having the valve sleeve therein has been fed through the presser unit, there remains the considerable length X of the work to be fed although no heating and pressing operation needs to be performed thereon. Pulling rolls H1 and H9 function to pull this length of the work rapidly through the apparatus after the corner has passed through the pressure plates 39 and 53, and thus the work is delivered away from the apparatus as rapidly as possible and its output is greatly increased, particularly on wide bags. It will also be noted that it is important to feed that portion of the work including the stripe II of adhesive between the pressure plates at a rate of speed consistent with the temperature of the plates to enable sufilcient softening of the adhesive to effect adhesion of the valve sleeve and bag. The relatively low speed drive of the draw rolls to accomplish this is effected by the speed-reducing drive I for the draw rolls.

Thus, the operator may rapidly feed one bag and valve sleeve assembly after the other through the apparatus, inasmuch as each assembly is fed through the apparatus in minimum time. The valve sleeves are efiectively secured tothe bags in the course of their passage between the pressure plates 39 and 53 due to the heating and softening of the thermoplastic adhesive II by the presser unit and the application of pressure to the work. It will be noted thatthe work is gripped between the knurled flange portions 89 and 9I of draw rolls 13 and 15 and between the knurled flange portions I01 and I99 of draw rolls 93 and 95 in its passage through the apparatus. This permits the portion of the work between the flange portions of the draw rolls to pass between the pressure plates 39 and 53, and be drawn evenly therethrough.

It will be understood that the heaters 35 and 49 are preferably under the control of a suitable thermostatic control device responsive to plate temperature so as to maintain plates 39 and 53 substantially at a predetermined desired temperature such as to soften the adhesive II' in accordance with the speed of travel of the work between the plates. It will be apparent that-the plates 39 and 53 must be maintained at higher temperatures for higher speeds of the draw rolls in order to soften the adhesive in the course of the passage of the work between the plates.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. The method of adhesively securing a bag valve sleeve to the corner of a bag comprising the steps of assembling a sleeve with a bag at a corner thereof and with thermoplastic adhesive therebetween, feeding this assembly corner first through a heated presser unit at such a rate of speed as to permit the adhesive to soften and unite the sleeve and bag under heat'and pressure, and subsequently pulling the remainder of the bag out of said unit at a substantially increased rate of speed thereby to clear the unit rapidly so that it may receive another bag and sleeve assembly.

2. The method of adhesively securing a bag valve sleeve in the corner of a bag comprising the steps of folding a sleeve having a transverse stripe of thermoplastic adhesive thereon substantially upon its longitudinal center line with the stripe on the outside of the sleeve, inserting the folded sleeve within the corner of the bag with the stripe engaging the inside wall of the bag adjacent its mouth, feeding said corner of the bag with the sleeve therein through a heated press'er unit atisuch a rate of speed asto permit the adhesive to soften and unite the sleeve and bag under heat and pressure, and subsequently pulling the remainder of the bag out of said unit at a substantially increased rate of speed thereby to clear the unit rapidly so that it may receive another ba and sleeve assembly.

- NORMAN E. WEEKS.

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

UNITED STATES PATENTS 5 Number Name Date 2,162,230 Salfisberg June 13, 1939 2,335,190 Minich Nov. 23, 1943 2,467,879 Billeb Apr. 19, 1949 2,483,860 Vredenburg Oct. 4, 1949

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