US3145129A

US3145129A - Apparatus for manufacturing bags

Info

Publication number: US3145129A
Application number: US48296A
Authority: US
Inventors: Russell J Williams; Harold D Reimer
Original assignee: Bemis Brothers Bag Co
Current assignee: Bemis Brothers Bag Co
Priority date: 1960-08-08
Filing date: 1960-08-08
Publication date: 1964-08-18
Anticipated expiration: 1981-08-18
Also published as: DE1284890B; GB932682A

Description

Aug. 1964 R. J. WILLIAMS ETAL 3,145,129

APPARATUS FOR MANUFACTURING BAGS Filed Aug. 8, 1960 5 Sheets-Sheet 1 Aug. 18, 1964 R. J. WILLIAMS ETAL APPARATUS FOR MANUFACTURING BAGS 5 Sheets-Sheet 2 Filed Aug. 8, 1960 mow mmm

1964 R. J WILLIAMS ETAL APPARATUS FOR MANUFACTURING BAGS 5 Sheets-Sheet 5 Filed Aug. 8, 1960 Aug E8, 1964 R. J. WILLIAMS ETAL 3,

APPARATUS FOR MANUFACTURING BAGS Filed Aug. 8, 1960 5 Sheets-Sheet 4 FIG. IH

Aug. 18, 1964 R. J. WILLIAMS ETAL APPARATUS FOR MANUFACTURING BAGS 5 Sheets-Sheet 5 Filed Aug. 8, 1960 FIG. 6.

United States Patent 3,145,129 AKPARATUS F101 MANUFACTURHNG BAGS Russell J. Williams, Clayton, and Harold D. Reimer, St.

Louis County, Mo, assignors to Bernis Bro. Bag (loinpauy, St. Louis, M0,, a corporation of Missouri Filed Aug. 8, 19nd, tier. No. 48,296 14- 'Claims. (Q1. 155-621) This invention relates to apparatus for manufacturing bags, and more particularly to apparatus for applying tabs to bags having an unravelable stitch type closure for anchoring the stitching and providing means for readily unraveling the stitching to open the bags.

In the copending coassigned application of Russell J. Williams et al., Serial No. 737,106, filed May 22, 1958, issued as US. Patent 2,978,164, April 4, 1961, there is disclosed a bag, and more particularly a multiwall paper bag, having at one end a closure constituted by a tape folded around the end of the bag and a line of stitching driven through the tape and through the walls of the bag and securing together the walls adjacent the end of the bag. The length of the tape is greater than the width of the bag, and the tape has end portions extending past the side edges of the bag. The stitching extends completely throughout the length of the tape, and is of a single thread readily unravelable chain stitch type which is unravelable by pulling the thread from one end of the stitching. A tab is releasably secured to the tape over the stated one end of the thread by adhesive, and is adapted to be grasped and pulled away from the tape. The adhesive anchors the thread against unraveling until it is desired to open the bag, and secures the thread to the tab at a point from which unraveling of the thread may be started, whereby, upon grasping and pulling the tab away from the tape, the thread is pulled away with the tab and unraveledv Among the several objects of this invention may be noted the provision of apparatus for applying such tabs to such bags in quantity production; the provision of such apparatus wherein the tabs are segmented from a continuous strip of tab material; and the provision of such apparatus wherein the tabs are heat-sealed to the bags. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

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

FIG. 1 is a plan view of an apparatus constructed in accordance with this invention;

FIG. 2 is a fragmentary side elevation of FIG. 1 on a larger scale than FIG. 1;

FIG. 3 is an enlarged vertical section taken substantially on line 3-3 of FIG. 1;

FIG. 4 is a vertical section taken on line 4-l of FIG. 3;

FIG. 5 is a vertical section taken on line 5-5 of FIG. 3;

FIG. 6 is a vertical section taken on line 6-6 of FIG. 3;

FIG. 7 is a semidiagrammatic view illustrating the operation of the apparatus;

FIG. 8 is a view in elevation taken on line 88 of FIG. 1; and

FIG. 9 is a perspective of a completed bag.

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

Referring to the drawings, first more particularly to FIG. 1, an apparatus constructed in accordance with this invention is shown to comprise a table 1 over which a 'ice succession of bags B are fed forward one after another at a predetermined speed with the bags extending transversely to the direction of feed (i.e., transversely with respect to the length of the table). The feeding of the bags is accomplished by means of a lug-type conveyor, generally designated 3, comprising a pair of endless chains 5 having lugs 7 thereon for pushing: bags forward along the table. Lugs 7 are spaced lengthwise of chains 5 at intervals greater than the width of the bags B, so that the bags being fed forward on the table are spaced apart as is clearly apparent from FIG. 1. Conveyors of this type are well known in the bag manufacturing art, and further details thereof are not believed necessary. It will suffice to say that the chains are trained around sprockets 9 on a shaft 11 at the leading or forward end of the table (which is its right end as viewed in FIG. 1), the chains having horizontal upper reaches which pass under the top of the table. The lugs 7 extend upward from the upper reaches of the chains through slots 13 extending lengthwise of the table top for engagement with the rearward edges of the bags to push them forward (i.e., toward the right as viewed in FIG. 1).

A guide 15 extends lengthwise along the top of the table at one side thereof (its right side as viewed in the direction of bag feed) for engagement by the right end of each bag being fed along the table to determine the position of the bag laterally with respect to the table. Guide 15 is constituted by an angle iron having an upstanding leg engageable by the bags. An. endless belt 17 arranged at an angle to the direction of the length of the table has its upper reach extending through an angled slot in in the top of the table for engagement by bags being fed along the table to impart a thrust to the bags toward the right side of the table thereby to keep their right ends against the guide 15.

As shown in FIG. 9, in each bag B is a gusseted multiwall paper bag, for example, closed at one end by means of a paper tape 21 folded around the end of the bag and a line of stitching 23 driven through the tape and the walls of the bag and securing the walls together adjacent the end of the bag. The tape may or may not be pasted to the bag. The length of the tape is greater than the width of the bag and the tape has

end portions

25 and 27 which extend past the side edges of the bag. The stitching extends completely throughout the length of the tape and may be driven through a narrow paper ribbon 29 constituting a so-called filler cord located on the side of the bag which is referred to as the needle side, this side being the side which faced the needle of the sewing machine employed for stitching. The stitching is of a single thread readily unravelable chain stitch type.

As will be readily understood by those familiar with the art, a bag is stitched by feeding it with the tape 21 folded around the end of the bag through a sewing machine having a needle which drives loops of the thread through the bag, thereby forming needle holes in the bag, the loops extending from the needle side of the tape through the needle holes to the other side of the tape, each loop being laid over on the said other side and extending through the preceding loop. This type of stitching is unraveled with ease by taking hold of that end of the thread which is at the trailing end of the stitching in relation to the passage of the bag through the sewing machine and pulling the thread. As herein illustrated, this end of the thread is its end at the end of projecting portion 25 of the tape. It will be understood that unraveling proceeds by successively pulling out the loops of the thread, the pulling out of each loop freeing the next loop so that it may be pulled out. The bags are completed to the stage in which they appear at the left of FIG. 1 prior to being fed over table 1. Each bag is placed on top of table l with its taped and stitched end at the right of the table for engagement with the guide 15, with the needle side of the bag facing upward, and with the end portion 25 of the tape (which is the end from which unraveling of the thread progresses) in trailing relation with respect to the direction of bag feed.

Mounted at right side of the table 1 toward its for ward end is a strip feeding and perforating unit generally designated 31. This is adapted to feed a strip S of tab material forward and hence downward toward the bags B being fed forward along the table, and to form transverse lines of weakness in the strip by perforating it on transverse lines extending completely across the strip spaced at intervals corresponding to the desired length for tabs T to be applied to the bags. Strip S has a coating A on one side of any suitable heat-scalable adhesive. As herein illustrated, the strip feeding and perforating unit 31 comprises a vertical side plate 33 extending above the top of the table at the forward end of guide 15 in a plane located somewhat outward from the inside face of the guide 15. Plate 33 extends down through a cutout 34 in the top of the table at its right forward corner portion and is mounted for adjustment lengthwise of the table as by means of bolts 35 received in a mounting plate 37 carried by the table and extending through horizontal slots 36 in plate 33. Extending inward from plate 33 above the table top are bolts 39 which serve as cantilevers carrying a second side plate 41. Plates 33 and 4-1 carry a shaft 43 on which is a lower strip

feed roll Plates

33 and 41 have vertical slots 47 extending down from the top thereof. Bearings 49 slidable in these slots have an upper shaft 51 journalled therein carrying an upper strip feed roll 53. This is biased downward toward the lower strip feed roll 45 by means of springs 55 reacting from caps 57 at the upper ends of the slots.

Plates

33 and 41 carry a shaft 59 forward of the shaft 43. Shaft 59 has a roll 61 thereon provided with an axial groove 63 in its periphery for receiving a perforating blade 65 on a perforating roll 67 mounted on a shaft 69 carried by

side plates

33 and 41 above and offset somewhat forward from shaft 59. Strip S is unwound from a roll suitable roll holder such as indicated at 71 in FIG. 3, is guided around a guide roll 73 carried by

plates

33 and 41, and thence passes between the feed rolls 45 and 53a The pass plane of these feed rolls is substantially horizontal. From the feed rolls 45 and 53, the strip passes between the perforating rolls 61 and 67, and thence angles forward and downward through a set of forward feed rolls 75 and 77. Roll 75, which is the lower roll of the set, is mounted on a shaft 79 journalled in the

side plate

33 and 41. Roll 77 is journalled in bearings 81 slidable in inclined slots 83 in the

side plates

33 and 41. Roll 77 is biased downward toward roll 75 by springs 85 reacting from caps 87 at the upper ends of slots 83. Strip S feeds through unit 31 with its adhesive side A facing downward.

Referring to FIG. 1, it will be seen that a main drive shaft 89 extends transversely under the table top rearward of the strip feeding and perforating unit 31. This shaft is driven at a predetermined speed via a chain and sprocket drive 91 from a suitable source of power (not shown). Conveyor shaft 11 is driven from main shaft 89 by a chain and sprocket drive 93. Shaft 13 which carries lower strip feed roll 45 of the strip feeding and perforating unit 31 is driven from main shaft 89 by means of a chain and sprocket drive 95. Referring to FIG. 8, it will be seen that shaft 43 has a gear 97 at its inner end meshing with an idler 99 carried by side plate 41 which in turn meshes with a gear 1191 on the inner end of shaft 59. Gear 101 meshes with a gear 1113 on the inner end of shaft 69 for driving the upper perforating roll 67. Gear 103 meshes with an idler 1% carried by side plate 41 which in turn meshes with a gear 1d! on the feed roll shaft 81 to drive the upper forward feed roll 77. Gear 107 meshes with a gear 109 on the lower forward feed roll shaft 79 to drive the lower forward feed roll 75. The speed ratio as between the main shaft 89 and the unit 31 R mounted on a and the gearing of the latter are such that the feed rolls of unit 31 act to feed strip S at a speed lower than the speed at which bags B are fed forward along the table top by the lugs 7 on conveyor chains 5, the ratio of the strip speed to the bag speed corresponding to the ratio of the desired length for tabs T to the spacing of the lugs 7. For example, if lugs 7 are spaced twenty-four inches, and tabs T are to be three inches long, the feed rolls of unit 31 act to feed strip S at one-eighth the speed of bags B. Thus, three inches of strip S are fed forward by unit 51 for each twenty-four inch movement of chains 5. The perforator rolls 61 and 67 rotate through one revolution on each twenty-four inch movement of chains 5 and perforate strip S at three-inch intervals. The forward strip feed rolls 75 and 77 are half the diameter of the rearward strip feed rolls 45 and 53, hence are driven at twice the rpm. of rolls 45 and 53 so that their peripheral speed is the same as that of rolls 45 and 53.

Mounted at the right side of the table 1 forward of the strip feeding and perforating unit 31 is a heat-sealing unit generally designated 111. This comprises a base plate 113 and

vertical side plates

115 and 117 extending up from the base plate. The base plate 113 is mounted on members such as indicated at 113 in FIG. 2 which extend out from the table below the top of the table. Side plate 115, which may be referred to as the inner side plate of the heat-sealing unit, is located in a vertical plane extending endwise of the table and located outward from the central vertical longitudinal plane of the strip feeding and perforating unit 31. The

side plates

115 and 117 carry bearings such as indicated at 119 for journalling a rearward shaft 121, an intermediate shaft 123 and a forward shaft 125 extending horizontally between the side plates through holes 127 (see FIGS. 36) in the side plates. These three shafts are located in a generally horizontal plane below the top of the table. The inner ends of the shafts project inward from the inner side plate 115. Each of the shafts has a wheel on its inner end in the plane of the strip feeding and perforating unit 31, the wheels being respectively designated 129, 131 and 133. Each of these wheels, as illustrated, may have a rim 135 of resilient heat-resistant material, such as silicone. The wheels extend upward in cutout 34 in the top of the table, and the top of each wheel is generally flush with the top of the table.

The

side plates

115 and 117 additionally carry bearings such as indicated at 137 for journalling a pair of

upper shafts

139 and 141 extending horizontally between the side plates through holes 14-3 in the side plates. These

shafts

139 and 141 are located in a generally horizontal plane above the table top. Shaft 139, which is the rearward shaft of the two, is located in a vertical transverse plane between the vertical planes of

shafts

121 and 123. Shaft 141 is located in a vertical transverse plane between the vertical planes of

shafts

123 and 125. A yoke 145 is pivoted on the rearward shaft 139 and extends rearward therefrom. This yoke comprises a pair of side arms 147 connected by a crossbar 149. The

side plates

115 and 117 have cutouts such as indicated at 151 at their upper rear corners. A shaft 153 is journalled in the arms 147 of the yoke 145 at their rearward ends, and projects inward beyond the inner side plate 115 through the cutout 151 of the inner side plate.

A collar 155 (see FIG. 6) is secured on the inner end portion of the shaft 155. Secured to this collar is a tubular member 157, which may be made of hard aluminum, for example. This tubular member 157 is coaxial with the shaft 153 and is integrally formed with a lobe 159 (see FIGS. 6 and 7) which extends therearound for about 160 of arc. This lobe has a circular periphery centered in the axis of the tubular member 157 and the shaft 153. It is located in the plane of the wheel 129, and is adapted to engage a tab T delivered by the strip feeding and perforating unit 31 and to press it down on a bag, the bag being backed by the wheel 129. A cartridge-type electrical heating element 161 (see FIG. 6) is pocketed in the tubular member 157 for heating the lobe, and is adapted to be energized via brushes 1113 carried by a brush holder 165 which is mounted on the crossbar 1 -9 of the yoke 145. The brushes engage a commutator 167 on the shaft 153, and the shaft is tubular for accommodating connections such as indicated at 159 to the heater.

The tubular member 157 containing the heater 161 and having the lobe 159 thereon is referred to as a sealing sector. It is thermally insulated from the shaft 153 by means of a disk 171 of insulation material (see FIG. 6) which is interposed between the inner end of the member 157 and the collar 155. An air cylinder 173 is provided for swinging the yoke 145 upward to raise the sealing sector 157 away from wheel 129 on shut-down of the apparatus to prevent burning of bags or the periphery of the wheel. Cylinder 173 is pivoted at its lower end as indicated at 175 on base plate 113. Piston rod 177 extending from a piston (not shown) in cylinder 173 is connected to crossbar 149 of the yoke as indicated at 179. When the piston of the air cylinder is retracted (down), the yoke 145 occupies the position illustrated in FIG. 3 wherein the lobe 159 of the sealing sector 157 is adapted to engage a tab T and press it down against a bag B backed by wheel 129. The yoke is held up by the piston rod so that the portion 181 of sector 157 between the leading and trailing ends 183 and 135 of the lobe is held up out of engagement with bags B.

Yokes

187 and 189 are pivoted on the upper forward shaft 141, yoke 187 extending rearward and yoke 189 extending forward therefrom. Each of these yokes comprises a pair of side arms 191 connected by a cross-bar 193. A shaft 195 is journalled in the arms of yoke 187 at their rearward ends, and a shaft 197 is journalled in the arms of yoke 189 at their forward ends. These shafts project inward beyond the inner side plate 115 of unit 111 through

notches

199 and 201 in plate 115 (see FIG. 3). A heat-sealing wheel 2113 is mounted on the inner end of shaft 195 for cooperation with wheel 131 and a heat-sealing wheel 2115 is mounted on the inner end of shaft 197 for cooperation with wheel 133. Wheels 2113 and 205 are identical, each carrying electrical heating elements 207 and being thermally insulated from its respective shaft by a disk 209 of insulation material (see FIG. 4). The heating elements 207 of each of wheels 2193 and 2135 are adapted to be energized via brushes 211 carried by a brush holder 213 mounted on the crossbar 193 of the

respective yoke

157 or 189. The brushes engage a commutator 215 on the respective shaft 195 or 197, and these shafts are tubular for accommodating connections such as indicated at 217 to the heating elements. Air cylinders such as indicated at 219 are provided for swinging

yokes

187 and 159 upward to raise wheels 2113 and 205 from

wheels

131 and 133 on shut-down of the apparatus to prevent burning of the bags or the peripheries of wheels 293 and 2015.

A drive shaft 221 for the heat-sealing unit 111 is journalled in bearings 119 on the

side plates

115 and 117, and is driven from main shaft 89 via a chain and sprocket drive 223 (see FIG. 1). A gear 225 on shaft 221 on the outside of side plate 117 meshes with

gears

227 and 229 on

shafts

123 and 125 to drive wheels 131 and 133 (see FIG. 2). An idler 231 on the outside of side plate 117 meshes with gear 227 and a gear 233 on shaft 121 to drive wheel 129. Idler 231 also meshes with a gear 235 on shaft 139. The latter carries a gear 237 on the inside of side plate 117 which meshes with a gear 239 on shaft 153 to drive sealing sector 157. Gear 225 also meshes with a gear 241 on shaft 1 1-1. The latter carries a gear 243 on the inside of side plate 117 meshing with

gears

245 and 247 on shafts 195 and 197 to drive heat-sealing wheels 2113 and 205. The drive 223 and the gearing of unit 111 are such that the peripheral speed of the lobe 159 of sealing sector 1 57 and the peripheral speed of each of the wheels of unit 111 corresponds to the speed of bag feed.

Operation is as follows:

Bags B are placed on top of the table 1, and are fed forward one after another along the top of the table at a suitable predetermined speed by lugs 7 on conveyor chains 5. As will be apparent, lugs 7 engage the rearward edges of the bags and push them forward along the table top at a speed corresponding to the speed of the chains 5. Each bag is placed on the table with its previously taped and sewn end contiguous to the guide 15, with its needle side up, and with the end 25 of the tape (which includes the trailing end of the stitching from which unraveling progresses) rearward. The bags may either be placed on the table by hand, or delivered directly to the table from a taping and sewing machine which applies the tape and sews the bag ends. As each bag approaches the sealing sector 157, it is urged toward the right against the guide for accurate alignment of stitching with the lobe 159 of the sealing sector.

Simultaneously with the forward feed of the bags, strips S of tab material is being pulled from roll R and fed forward by the rearward strip feed rolls 45 and 53 to and through the perforating rolls 61 and 67. Upon each revolution of the perforating rolls, the strip is perforated on a transverse line extending completely across the strip, these transverse lines of perforation recurring at intervals corresponding to the desired length for tabs T. The perforated strip issuing from the perforating rolls is fed downward toward the nip of the sealing sector and the rearward wheel 129 by the forward strip feed rolls and 77. As previously made clear, the strip speed is lower than the speed at which the bags are fed along the top of the table by lugs 7 on conveyor chains 5. The coated side A of strip S faces downward.

The operation of the strip feeding and perforating unit 31 and the operation of the sealing sector 157' are so timed in relation to the feeding of the bags B along the top of the table that the forward end of strip S engages a bag B adjacent the trailing end of the tape 21 on the bag just before the leading end 183 of the lobe 159 of sealing sector 157 (which rotates counterclockwise as viewed in FIGS. 3 and 7) comes into engagement with the forward end of the strip. This allows the forward end of the strip to enter in underneath the leading end of the lobe without interference, and assures proper placement of the leading end of the strip relative to the trailing end of tape 21. Immediately thereafter, the leading end 183 of the lobe comes around and engages the end of the strip and presses it down on tape 21 over the stitching. Since the sealing sector 157 is rotating at a speed corresponding to the speed of the bags, the forward end portion of the strip S is immediately accelerated up to the speed of the bags, and the leading end portion of the strip S is snapped off at the line of perforations made in the strip by the perforating rolls spaced from the leading end of the strip a distance corresponding to the desired tab length to segment a tab T from the strip. This tab is pressed down upon the tape over the stitching by lobe 159 (see FIG. 7). Sector 157 is maintained heated by the heater 161 to a temperature sufficient to fuse the adhesive A on the tab, and the tab, being pressed down on the tape, adheres to the tape over the stitching. The timing is also such that the forward end of strip S being fed forward by unit 31 engages a bag B at a point spaced forward from the rearward edge of the bag a distance less than the length of tab T. Accordingly, the rearward end portion of the tab projects rearward beyond the end of tape extension 25, thereby providing a projecting tab end portion adapted to be grasped and pulled to unravel the stitching. The heat sealing of the tab T to the bag by the sealing sector 157 is of a preliminary nature, and completion of the sealing is accomplished by the heat-sealing wheels 2413 and 205 as the ends of the bags with the tabs T thereon travel through the nip of

wheels

203 and 131 and

Wheels

205 and 133.

The vertical plane of the axes of sealing sector 157 and the wheel 129 may be referred to as a tab-applying station, the stitched end of each bag B being fed forward by the bag feeding means constituted by chains and lugs 7 passing through this station in the course of its travel. Unit 31 acts to supply to the bags at this tab-applying station a succession of tabs T (each having a length less than the bag width) in such manner that the leading end of each successive tab reaches said station at the time that a point on the bag in the line of the stitching thread 23 spaced forward of the trailing end of the thread (i.e., the end of the thread at the rearward end edge of end portion 25 of tape 21) a distance less than the length of the tab reaches said station. This point on the bag is that appearing in FIG. 7 in the transverse vertical plane of the axis of sealing sector 157. The latter constitutes means for adhering the tabs to the bags over the stated end of the thread with the tabs extending outward in trailing direction (i.e., toward the left as viewed in PEG. 7 beyond the trailing end of the thread).

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

As various changes could be made in the above constructions 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.

We claim:

1. Apparatus for applying tabs to bags having a single-thread unravelable stitch type closure at one end thereof, the stitching being unravelable by pulling one end of the thread, comprising means for feeding a suc cession of such bags in a forward direction one after another at a predetermined speed with the bags extending transversely to the direction of feed, spaced apart in the direction of feed, with their stitched ends in alignment, and with the said one end of the thread at the trailing end of the closure in respect to the direction of feed, means for feeding a strip of tab material toward the bags at a speed lower than the speed of bag feed with the strip in line with the stitching, means for providing transverse lines of weakness across the strip spaced at intervals along the length of the strip corresponding to the desired tab length, said strip feeding means operating in such timed relation to the feeding of the bags that the leading end of the strip engages a bag at a point spaced forward of the trailing end of the thread a distance less than the tab length, and means for accelerating the leading end portion of the strip up to the speed of bag feed, thereby snapping off said leading end portion of the strip at a line of weakness spaced from the leading end of the strip a distance corresponding to the desired tab length to segment a tab from the strip, and for adhering said tab to the bag over the trailing end portion of the stitching.

2. Apparatus as set forth in claim 1 adapted for operation with a heat scalable strip having a heat-scalable adhesive thereon, wherein means is provided for heating the tabs to effect heat-sealing thereof to the bags.

3. Apparatus as set forth in claim 2 wherein said accelerating means is adapted to press the tabs against the bags and said heating means is incorporated in said accelerating means for heating the latter so that it acts to heat-seal the tabs to the bags.

4. Apparatus as set forth in claim 3, wherein the heat sealing of the tabs to the bags by said accelerating means is a preliminary heat sealing, and wherein additional heatsealing means is provided for heating the tabs and pressing them against the bags after the preliminary heat sealing by said acclereating means.

5. Apparatus for applying tabs to bags having a singlethread unravelable stitch type closure at one end thereof, the stitching being unravelable by pulling one end of the thread, comprising means for feeding a succession of such bags in a forward direction one after another at a predetermined speed with the bag extending transversely to the direction of feed, spaced apart in the direction of feed, with their stitched ends in alignment, and with the said one end of the thread at the trailing end of the closure in respect to the direction of feed, means for feeding a strip of tab material toward the bags at a speed lower than the speed of bag feed with the strip in line with the stitching, said strip having a coating of heat-scalable material on one side thereof and being fed toward the bags with said one side facing the bags, means for perforating the strip on transverse lines spaced at intervals along the length of the strip corresponding to the desired tab length, said strip feeding means operating in such timed relation to the feeding of the bags that the leading end of the strip engages a bag at a point spaced forward of the trailing end of the thread a distance less than the tab length, and means for accelerating the leading end portion of the strip up to the speed of bag feed, thereby snapping off said leading end portion of the strip at a time of perforations spaced from the leading end of the strip a distance corresponding to the desired tab length thereby to segment a tab from the strip, and for heating and pressing said tab against the bag over the trailing end portion of the stitching to cause it to become heat-sealed to the bag over the stitching.

6. Apparatus as set forth in claim 5 wherein said accelerating, heating and pressing means comprises a rotatable sealing sector having heating means incorporated therein, and means for driving said sealing sector so that its peripheral speed corresponds to the speed of bag feed.

7. Apparatus as set forth in claim 6 wherein the heat sealing of the tabs to the bags by the sealing sector is a preliminary heat sealing, and wherein additional heatsealing means is provided for heating the tabs and pressing them against the bags after the preliminary sealing by said sector.

8. Apparatus as set forth in claim 5 comprising a table along the top of which the bags are fed forward, the bag feeding means comprising conveyor chains having lugs extending upward through slots in the table for engaging the rearward edges of the bags.

9. Apparatus for applying tabs to bags having a singlethread unravelable stitch type closure at one end thereof, the stitching being unravelable by pulling one end of the thread, comprising means for feeding a succession of such bags in a forward direction one after another at a predetermined speed with the bags extending transversely to the direction of feed, spaced apart in the direction of feed, with their stitched ends in alignment, and with the said one end of the thread at the trailing end of the bag closure in respect to the direction of feed, the stitched end of each bag being fed forward by said bag feeding means passing through a tab-applying station in the course of its travel, means for supplying to the bags at said station a succession of tabs each having a length substantially less than the bag width, means for operating said tab-supplying means in such timed relation to the bag feeding means that the leading end of each successive tab reaches said station at the time that a point on the bag in the line of the thread spaced forward of the trailing end of the thread a distance less than the length of the tab reaches said station, and means for adhering the tabs to the bags over the said one end of the thread with the tabs extending outward in trailing direction beyond the trailing end of the thread.

10. Apparatus as set forth in claim 9 adapted for operation with heat-scalable tabs, and wherein said adhering means is adapted to heat the tabs for heat-sealing them to the bags.

11. Apparatus as set forth in claim 9 wherein the means for supplying the succession of tabs to the bags comprises means for segmenting tabs from a continuous strip of tab material.

12. Apparatus as set forth in claim 11 adapted for operation with a continuous strip of heat-scalable tab material wherein said adhering means is adapted to heat the tabs for heat-sealing them to the bags.

13. Apparatus for applying tabs to bags having a singlethread unravelable stitch type closure at one end thereof, the stitching being unravelable by pulling one end of the thread, comprising means for feeding a succession of such bags in a forward direction one after another at a predetermined speed with the bags extending transversely to the direction of feed, spaced apart in the direction of feed, with their stitched ends in alignment, and with the said one end of the thread at the trailing end of the bag closure in respect to the direction of feed, the stitched end of each bag being fed forward by said bag feeding means passing through a tab-applying station in the course of its travel, means for continuously feeding a continuous strip of tab material toward said station at a speed lower than the speed of the bags with the strip in line with the stitching, means for segmenting from the strip tabs each having a length substantially less than the bag width, accelerating the tabs up to the speed of the bags, and adhering them to the bags over the said one end of the thread, and means for operating said strip feeding and segmenting means in such timed relation to the bag feeding means that the leading end of the strip reaches said station at the time that a point on the bag in the line of the thread spaced forward of the trailing end of the thread a distance less than the tab length reaches said station, and such that a tab is then segmented from the strip, each tab being adhered to a respective bag over the said one end of the thread with the tab extending outward in trailing direction beyond the trailing end of the thread.

14. Apparatus as set forth in claim 13 adapted for operation on a strip of heat-scalable tab material wherein said adhering means is adapted to heat the tabs for heatsealing them to the bags.

References Cited in the file of this patent UNITED STATES PATENTS 2,062,280 Aanesen Dec. 1, 1936 2,291,280 Joplin July 28, 1942 2,543,220 Ardell Feb. 27, 1951 2,639,256 Meyer May 19, 1953 2,678,748 McCain et a1 May 18, 1954

Claims

1. APPARATUS FOR APPLYING TABS TO BAGS HAVING A SINGLE-THREAD UNRAVELABLE STITCH TYPE CLOSURE AT ONE END THEREOF, THE STITCHING BEING UNRAVELABLE BY PULLING ONE END OF THE THREAD, COMPRISING MEANS FOR FEEDING A SUCCESSION OF SUCH BAGS IN A FORWARD DIRECTION ONE AFTER ANOTHER AT A PREDETERMINED SPEED WITH THE BAGS EXTENDING TRANSVERSELY TO THE DIRECTION OF FEED, SPACED APART IN THE DIRECTION OF EED, WITH THEIR STITCHED ENDS IN ALIGNMENT, AND WITH THE SAID ONE END OF THE THREAD AT THE TRAILING END OF THE CLOSURE IN RESPECT TO THE DIRECTION OF FEED, MEANS FOR FEEDING A STRIP OF TAB MATERIAL TOWARD THE BAGS AT A SPEED LOWER THAN THE SPPED OF BAG FEED WITH THE STRIP IN LINE WITH THE STITCHING, MEANS FOR PROVIDING TRANSVERSE LINES OF WEAKNESS ACROSS THE STRIP SPACED AT INTERVALS ALONG THE LENGTH OF THE STRIP CORRESPONDING TO THE DESIRED TAB LENGTH, SAID STRIP FEEDING MEANS OPERATING IN SUCH TIMED RELATION TO THE FEEDING OF THE BAGS THAT THE LEADING END OF THE STRIP ENGAGES A BAG AT A POINT SPACED FORWARD OF THE TRAILING END OF THE THREAD A DISTANCE LESS THAN THE TAB LENGTH, AND MEANS FOR ACCELERATING THE LEADING END PORTION OF THE STRIP UP TO THE SPEED OF THE BAG FEED, THEREBY SNAPPING OFF SAID LEADING END PORTION OF THE STRIP AT A LINE OF WEAKNSS SPACED FROM THE LEADING END OF THE STRIP AT A LINE OF WEAKNESS SPACED FROM THE LEADING END OF THE STRIP A DISTNCE CORRESPONDING TO THE DESIRED TAB LENGTH TO SEGMENT A TAB FROM THE STRIP, AND FOR ADHERING SAID TAB TO THE BAG OVER THE TRAILING END PORTION OF THE STITCHING.