US 3553934 A
Description (OCR text may contain errors)
Jan. 12, 1971 K, R ]OHNSQN ETAL 3,553,934
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7 Filed 5195.20; 1968 PACKAGING MACHINE ,FOR FORMING AND FILLiNG BAGS OF DIFFERENT.- LENGTHS AND WIDTHS V l4 Sheets-Sheet 13 cjlT-romozzy-f 1971 K. R. JOHNSON ETAL 3,553,934
PACKAGING MACHINE FOR FORMING AND FILLING BAGS OF DIFFERENT LENG'IHS AND WIDTHS Filed Feb. 20, 1968 14 Sheets-Sheet 14 [g LJ A/ m I de/znea. Qciohnu fl Qaerfiemu'e zwag m/xvw United States Patent Int. Cl. B65h 1/02 US. Cl. 53-183 7 Claims ABSTRACT OF THE DISCLOSURE Bags which may vary in length and width within preselected ranges from one run to another are formed from a web of flexible material and are filled with a quantity of product as they are advanced in vertical planes along a horizontal path by a packaging machine. To reduce the number of adjustments necessary for changing over the machine from running bags of one length and width to running bags of a different length and width, the machine is capable of being set up to maintain the upper ends of both long and short bags moving along a common operating or datum line during the advance of the bags and, at the same time, to maintain the longitudinal center lines of both wide and narrow bags in exact coincidence with the working centers of various mechanisms spaced along the path for operating on the bags before, during and after filling.
The disclosure also specifically pertains to a number of new and improved mechaisms for forming and handling the bags, to the drive mechanism of the machine, and to the ease of adaptability of the dilferent elements of the machine to either right or left hand operation.
CROSS-REFERENCE TO A RELATED APPLICATION This application is a continuation-in-part of our copending application entitled Method and Machine for Forming and Filling Bags, Ser. No. 689,177, filed Dec. 8, 1967.
BACKGROUND OF THE INVENTION This invention relates to a packaging method and machine wherein bags are formed from a continuous web of flexible material in a bag-making section of the machine and thereafter are transferred to a bag-filling section for filling With measured quantities of product.
In the bag-making section of such a machine, the web is folded into a pair of face-to-face strips which are advanced in upright planes along a substantially horizontal path into a sealing station where they are sealed together along longitudinally spaced lines extending crosswise of the strips so as to form a row of bags interconnected at their adjacent side edges by the newly formed seals. Thereafter, the leading bag is severed from the row and is transferred to the bag-filling section of the machine.
In the bag-filling section, the bags are advanced open end up along an extension of the path by a conveyor which includes a series of spaced clamps operable to receive and grip the bags as the latter are cut from the row and operable to hold the bags for advancement in generally upright planes. During such advance, various operating mechanisms spaced along the conveyor perform functions such as preparing the bags for filling, depositing the product into the bags, and sealing the open ends of the bags to enclose the product therein.
3,553,934 Patented Jan. 12, 1971 SUMMARY OF THE INVENTION The present invention aims to simplify significantly the changing over of a packaging machine of the above character from an operation of forming and filling bags of one size to an operation of forming and filling bags of a different size within a preselected range of sizes. A primary object of the invention thus is to provide a new, improved and extremely versatile packaging machine in which such a changeover may be accomplished quicker and more easily than formerly has been possible with prior machines of the same general type.
More specifically, the invention contemplates a machine in which the upper ends of bags of all lengths within the range are maintained on a common datum line during forming and filling of the bags so that mechanisms which operate on the upper ends of the bags need not be raised or lowered each time the machine is changed over to form and fill shorter or longer bags. In addition, the longitudinal center lines of bags of all widths within the range are constantly maintained in coincidence with the working centers of various ones of the operating mechanisms during advancement of the bags in order to avoid the necessity of adjusting the mechanisms to accommodate wider or narrower bags.
Other aims of the invention are to provide a novel web folder which is vertically adjustable to form bags of diiferent lengths while maintaining the upper end of each bag extending along the datum line; to provide a new and improved adjustable mounting for a sealing unit adapted to seal the strips together; and to center the sealing force applied by the unit on the vertical centers of the seals of the bags regardless of the length of the seals.
The invention also resides in the self-contained actuation of several operating mechanisms of the bag-making section to enable simplification of the main drive unit of the machine and to provide greater flexibility of operation between the bag-making section and the bag-filling section.
In more detailed aspects, the invention is characterized by the novel construction and location of the conveyor of the bag-filling section to prevent the conveyor from being fouled by the product being packaged and to prevent the conveyor from interfering with the bag operating mechanisms; by the construction of the bag-holding clamps in the form of inexpensive cartridges well adapted for manufacture by modern mass production techniques; and by the provision of relatively simple and trouble-free mechanisms for opening and closing the clamps during transfer of the bags to and from the bag-filling section of the machine.
An additional feature of the invention includes the construction of the machine from modular units and interchangeable parts capable of being assembled for either left or right hand operation. Also, provision is made of a novel peaked roof which sheds loose product away from the machine and which may be used interchangeably with left and right hand machines.
Other objects and advantages will become apparent as the following description proceeds, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical bag which may be formed and filled by a packaging machine embodying the novel features of the present invention.
FIG. 2 is a schematic view of the bag-making section of the machine.
FIG. 3 is a schematic view illustrating the manner of maintaining the upper ends of bags of various lengths extending along the common datum line.
FIG. 4 is a schematic view illustrating the manner of maintaining the center lines of bags of various widths in coincidence with the working centers of the operating mechanisms of the machine.
FIG. is a fragmentary side elevation of the bag-making section when viewed from the front side of the machine.
FIG. 6 is an enlarged fragmentary view of the forward end portion of the bag-making section shown in FIG. 5, parts being broken away and shown in section.
FIG. 7 is an enlarged fragmentary cross-section taken along the line 77 of FIG. 6.
FIG. 8 is a fragmentary cross-section taken along the line 88 of FIG. 6.
FIG. 9 is an enlarged fragmentary cross-section taken along the line 9-9 of FIG. 5.
FIG. 9a is a fragmentary perspective View of parts shown in FIG. 9.
FIG. 10 is an enlarged fragmentary cross-section taken along the line 10-10 of FIG. 5.
FIG. 11 is a fragmentary cross-section taken along the line 1111 of FIG. 10.
FIG. 12 is a fragmentary cross-section taken along the line 12-12 of FIG. 11.
FIG. 13 is an enlarged elevation of parts shown in FIG. 12.
FIG. 14 is an enlarged elevation of parts shown in FIG. 12 with certain elements being broken away and shown in section.
FIG. 15 is an enlarged fragmentary cross-section taken along the line 1515 of FIG. 12.
FIG. 16 is a fragmentary side elevation of the bagfilling section as viewed from the front side of the machine.
FIG. 17 is an enlarged fragmentary cross-section taken along the line 17-17 of FIG. 16.
FIG. 18 is an enlarged fragmentary cross-section taken along the line 18-18 of FIG. 16.
FIG. 19 is an enlarged perspective view of parts shown in FIG. 18.
FIG. 20 is an enlarged fragmentary cross-section taken along the line 20-20 of FIG. 18.
FIG. 21 is an enlarged fragmentary cross-section taken along the line 2121 of FIG. 16.
FIG. 22 is an enlarged fragmentary cross-section taken along the line 2222 of FIG. 16.
FIG. 23 is a fragmentary view similar to FIG. 22 but showing parts in adjusted positions.
FIG. 24 is an enlarged fragmentary cross-section taken along the line 2424 of FIG. 22.
FIG. 25 is an enlarged fragmentary perspective view of parts shown in FIGS. 22 and 24.
FIG. 26 is an exploded perspective view schematically showing a right hand machine.
FIG. 27 is an exploded perspective view schematically showing a left hand machine.
FIG. 28 is a. perspective view of a bridge for supporting an operating mechanism.
FIGS. 29 and 30 are perspective views of parts shown in FIG. 11.
FIG. 31 is a perspective view schematically showing the conveyor and its drive unit.
DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the invention is embodied in a packaging machine for converting a continuous strip or web 30 of flexible ma terial such as foil, plastic or paper into pouches or bags 32, filling the same with one or more measured quantities of product, and thereafter closing the filled bags and transferring the bags to a suitable receptacle or to an automatic cartoner (not shown). Herein, each bag is formed of heatsealable material such as polyethylene film and comprises two opposing face-to-face side panels 33 joined along their lower margins by a fold 34 and sealed together along their two side margins as indicated at 35. The product, which in this instance consists of a granular or powdered food substance, is deposited into the upper end of the bag and is enclosed therein by a heat seal 36 joining the upper margins of the side panels.
Basically, the machine comprises a bag-making section 37 (FIGS. 2 and 5) with which the bags 32 are formed as the web 30 is advanced in a horizontal direction along a predetermined path. Downstream from and disposed end-to-end with the bag-making section is a bag-filled section 39 (FIGS. 2 and 16) to which the newly formed bags are transferred for filling and closing during advancement along an extension of the path.
In forming the bags 32, a length of the web 30 is drawn endwise off of a supply roll 40 which is journaled to turn about a horizontal axis on a support 41 (FIG. 6) projecting forwardly from the front end of the bag-making section 37. From the supply roll, the web is trained upwardly over a guide roller 43 and downwardly around a springloaded dancer roller 44 operable to maintain tension on the web and mounted for up and down movement in a pair of slotted guides 45 upstanding from the support. The web then passes upwardly over a second guide roller 46 and downwardly beneath a forming member or folding plow 47 which folds the web upwardly along its longitudinal center line to form a pair of face-to-face strips 49 disposed in vertical planes and each being equal in height to approximately half the width of the web. As the strips are advanced along the path, a pair of heated side sealing bars 50 (FIGS. 2 and 9) disposed in upright positions on opposite sides of the strips periodically reciprocate into and out of engagement with the same to seal the strips together along longitudinally spaced lines 51 (FIGS. 4 and 5) extending crosswise of the strips thereby to form a row of connected bags having open upper ends. During such sealing and just prior to the time the bags are filled, their upper edges straddle and are spread apart by elongated splitter bars 53 and 54 (FIGS. 2, 5 and 16) extending above the path along the bag-making and bagfilling sections 37 and 39, respectively.
With continued advance of the folded web 30 after sealing, a cutting unit 55 (FIGS. 2 and 12) disposed downstream from the sealing bars 50 separates successive bags 32 from the leading end of the row by cutting through the seals 51 midway between their side edges so that each seal 51 forms the trailing side seal 35 of one bag and the leading side seal 35 of the next succeeding bag. The sealing bars and the cutter are timed to operate once each time the web advances through a distance equal to the width of the ultimate bags to insure sealing and severing of the web along properly spaced lines.
Upon being severed from the web 30, each bag 32 is delivered to the bag-filling section 39 of the machine at a transfer station 56. In this instance, the bag-filling section includes a conveyor 57 (FIGS. 2 and 11) for picking up each cut off bag and for advancing the bags in spaced edgewise relation and in upright positions through a number of stations where various mechanisms operate on the bags. For example, during advance of the bags by the conveyor, a bag opener 59 (FIGS. 2, 16 and 21) positioned alongside the conveyor in a filling station 60 first pulls apart the upper ends of the side panels 33 of each bag and thereafter a conventional dispenser 61 (FIGS. 2 and 16) disposed above the conveyor deposits a measured charge of product into the opened bag through a spout which is usually lowered into the bag. The filled bags then are advanced between a pair of horizontal sealing bars 63 (FIGS. 2 and 16) extending longitudinally of the bag path and periodically shiftable into engagement with the bags to seal the upper ends closed and thereby form the top seals 36. After advancement between a pair of similarly disposed cooling bars 64 which harden the newly formed top seals, the bags are removed from the conveyor and are transferred to the cartoner by a pick-off device 65 (FIGS. 2, 16 and 22) located downstream from the cooling bars.
In many packaging operations, a single machine of the above type often may be used for forming and filling a series of bags of one width and then switched over to form and fill a series of bags of a different width. This is particularly true not only with respect to smaller plants in which different products may be packaged with the same machine on different days but also from the standpoint of contract packagers who may run one width of bag for a few hours, switch over to another width for a few hours, and then make still another changeover in the same day.
An important aspect of the present invention is based on a novel concept that all bags, regardless of their width, can be kept centered on the working centers of various ones of the operating mechanisms of the bag-filling section 39 during advancement of the bags and that, by such centering of the bags, the machine can be changed over from running a first series of bags of one width to running a second series of bags of a different width without requiring adjustment of the working centers of the mechanisms along the path and into coincidence with the longitudinal center lines of the second bags during the interval between the two runs. In carrying out this concept, an imaginary datum line is established upon which each bag formed during a run is centered as the bag is cut off from the web 30. Certain operating mechanisms of the bag-filling section 39 (such as the bag-opener 59, the dispenser 61 and the pick-off device 65) are set up with their working centers operating permanently along li nes which are spaced from the datum line by distances such that, with each bag centered on the datum line during cut off, the centers of the bags automatically coincide with the working centers when the bags are subsequently presented to the mechanisms. When changing over the machine to form and fill a second series of bags which differ in width from those of the previous run, unique and relatively simple adjustments are made to the cutter 55 and the conveyor 57 to maintain the second bags centered during cut off on the same imaginary datum line as the first bags so that the second bags, when presented to the operating mechanisms, also will coincide with the working centers of the mechanisms with the latter remaining set up exactly the same as during the preceding run.
While the invention is applicable equally Well to a packaging machine adapted to advance the web 30 and the bags 32 with a continuous and uninterrupted motion, it herein is disclosed specifically in conjunction with a socalled intermittent motion machine of the type in which the web and the bags are advanced step-by-step with the several operating mechanisms working on the web and the bags during dwells which occur in the motion between successive steps. More specifically, step-by-step advance of the web is effected by a pair of coacting feed rolls 66 and 67 (FIGS. 2 and frictionally engageable with the web between the sealing bars 50 and the cutter 55 and intermittently rotatable through arcs sufficient to advance the web through steps equal in length to the width of the bags being formed. For example, when forming bags 32 having a width of four inches, the feed rolls will be set to advance a four inch length of web during each step. The side sealing bars move into engagement with the folded web during each dwell and thus the distance between successive side seals 51 corresponds to the width of the bags. The cutter also operates while the Web is dwelling and is spaced downstream from the side sealing bars a distance equal to a multiple of the bag width so that, after each advance of the web, one side seal 51 dwells alongside the cutter with the bag on the leading end of the web projecting downstream of the cutter and positioned in the transfer station 56. By way of example and as shown schematically in FIG. 4, the spacing SC between the sealing bars and the cutter may be established at twelve inches when the machine is set up to run bags 32 each having a width of four inches.
Before each leading bag 32 is cut off from the Web 30, its leading edge is gripped in the transfer station 56 by a pair of grippers or clamps 69 (FIGS. 4, l7 and 19) on the conveyor 57. Herein, the conveyor comprises an endless chain having a straight run passing through the transfer station and alined with the path of the web. Several pairs of the clamps 69 are attached along the chain and are equally spaced from each other a distance greater than the width of the widest bag to be handled by the machine, the spacing or pitch P (FIG. 4) of the clamps being approximately eight inches in this instance. The chain is advanced intermittently and is timed such that one pair of clamps is always dwelling in the transfer station each time the leading end of the web is advanced past the cutter 55. During each such dwell, the clamps in the transfer station are opened to receive the advancing end of the web and, shortly after the latter dwells, the clamps are closed thereby to grip the leading bag securely before the cutter severs the bag from the web.
During cut off, each bag 32 dwells in the transfer station 56 with its longitudinal or vertical center line 1 ing along an imaginary vertical line DL (FIGS. 2 an 4) which is disposed parallel to the cutter 55 in the plane of the bag. The line DL defines the datum line to whicff the positions of the working centers of certain mechanisms of the bag-filling section 39 are referenced. To center the bags on the datum line during cut off, the horizontal spacing CD (FIG. 4) between the cutter and the datum line is always set at half the width of each bag and, in the case of the four inch bags 32, the spacing CD is two inches. Also, the chain 70 is positioned such that, with a pair of clamps 69 dwelling and properly gripping the leading edge of a bag in the transfer station, the horizontal spacing DG between the datum line DL and a vertical line of reference on the clamps is a predetermined value. For purposes of discussion, it may be assumed that the line of reference on the clamps is taken along the leading edge of a bag in the transfer station. Thus, the distance DG is two inches when the four inch bags 32 are being run.
After each bag 32 has been gripped by a pair of clamps 69 and cut off from the web 30, it is advanced by the chain 70 and dwells successively in the different stations where the bag opener 59, the dispenser 61, the top sealing and cooling bars 63 and 64, and the pick off device 65 are located to operate on the bag during the intervals when the latter is dwelling. As shown schematically in FIG. 4, these various mechanisms are located along the path of the chain with their operating or working centers advantageously lying along or centered on imaginary vertical lines which are spaced horizontally from the datum line DL by multiples of the pitch P of the clamps. In addition, the chain is timed to advance each gripped bag in equal steps each corresponding in length to the pitch of the clamps. Accordingly, since the bag initially dwells during cutoff in a centered position on the datum line DL and since the operating mechanisms are spaced from the datum line by multiples of the bag advance, the bag subsequently dwells in each of the stations with its vertical center line coinciding exactly with the working centers of the mechanisms. In this way, the bags are alined perfectly with the mechanisms as the latter operate on the bags.
In keeping with the invention, bags which are wider or narrower than the bags formed on a preceding run are kept centered on the same datum line DL during cutoff by adjusting the center line of the cutter 55 relative to the datum line between runs by a distance equal to one-half the difference between the width of the previously formed bags and the width of the bags to be formed on the next succeeding run. Also, to effect transfer of the wider or narrower bags to the conveyor 57, the position which the clamps 69 assume when dwelling in the transfer station 56 is adjusted relative to the datum line by an amount equal to the adjustment of the cutter but in an opposite direction.
To explain these and other adjustments which are made when the machine is changed over from running bags of one width to running bags of a different width, let it be assumed that the machine has been set up as described above to run four inch bags 32 and that it is desired to adjust the machine to run narrower bags 32N (FIG. 4) each having a width of three inches. First, the feed rolls 66 and 67 are adjusted to advance the web 30 through three inch steps instead of the four inch steps of the former run. Next, the cutter 55 is adjusted from its previous position and toward the datum line DL by a distance equal to one-half the difference between the width of the bags 32 and the width of the narrow bags 32N. That is, the cutter is shifted toward the datum line by a distance of 0.5 of an inch so that the spacing CD-N between the cutter and the datum line becomes 1.5 inches. Finally, the seal bars 50 may be adjusted toward the cutter to reduce the spacing SC-N between the seal bars and the cutter to nine inches which is a multiple of width of the narrow bags 32N.
Now, when the folded web 30 is advanced along the path, the sealing bars 50 will form the side seals 51 at three inch increments thereby to form the narrow bags 32N. Then, with each advance of the web, one bag 32N will advance past the cutter 55 and will dwell with its trailing seal positioned in line with the cutter. Since the spacing CD-N between the cutter and datum line is 1.5 inches or half the width of the bag 32N, the latter, like the wider bag 32, will dwell during cutoff with its vertical center line centered exactly on the datum line DL. Because the bag 32N is narrower, however, its leading edge will assume a different position in the transfer station 56 than did the leading edges of the previously formed bags 32, and will be disposed 0.5 of an inch closer to the datum line.
To effect transfer of the narrow bags 32N to the conveyor 57 in spite of the difference in the positioning of their leading edges in the transfer station 56, the phasing of the clamps 69 relative to the datum line DL is changed between the two runs by bodily shifting of the chain 70 in order to adjust the clamps closer to the datum line and into position to receive and grip the leading edges of the narrow bags. That is to say, the chain is shifted bodily when the machine is changed over so that each pair of clamps presented to the transfer station will dwell in a gripping position which is closer to the datum line than the position occupied by the clamps during the preceding run. The difference between the two positions is equal to one-half the difference in bag width and, in the case of changing from four inch bags to three inch bags, the clamps are adjusted toward the datum line such that the spacing DG-N becomes 1.5 inches or 0.5 of an inch less than the previous spacing DG.
With the machine thus changed over, each narrow bag 32N is gripped by a pair of dwelling clamps 69 during cutoff and is centered automatically on the datum line DL to which the working centers of the operating mechanism are referenced. Accordingly, advance of the bag 32N by the chain 70 through steps of the same length as before causes the bag to dwell in the various station with its vertical center line also positioned in exact coincidence with the centers of the mechanisms even though the latter remain set in the same positions as during the previous run. Thus, there is no need between runs to adjust such mechanisms as the bag opener 59, the dispenser 61 and the pick-off device 65 along the path and into alinement with the centers of the narrow bags. This is particularly important with respect to the dispenser which is quite large and difficult to adjust. Elimination of the need of adjustment of the dispenser and the other operating mechanisms therefore results in a substantial saving in the amount of time and effort required to change over the machine and thu significantly increases the versatility of the machine.
Adjustments similar but reverse to those described above are made when the machine is changed over from running the narrow three inch bags 32N to running wider bags 32W (FIG. 4) which, for example, may be five inches wide. The feed rolls 66 and 67 are adjusted to advance a five inch length of web upon each step, the cutter 55 is adjusted away from the datum line DL by one additional inch to increase the spacing CD-W to 2.5 inches, and the sealing bars 50 are adjusted away from the cutter to increase the spacing SC-W to ten inches or a multiple of the new bag width. After the chain 70 has been shifted to move the clamps 69 away from the datum line by one additional inch and to increase the spacing DG-W to 2.5 inches, the machine is ready to run the five inch bags. As before, each bag 32W first is centered on the datum line during cutoff and then dwells in each of the stations with its vertical center line coinciding with the working centers of the operating mechanisms. Accordingly, changing over of the machine to run wider bags also may be accomplished without adjustment of the mechanisms along the bag path and may be effected as quickly and easily as the changeover to narrow bags.
In addition to running bags of different widths, the same machine often may be changed over to form and fill a series of bags of a different height or length than those formed and filled during a preceding run. According to another important aspect of the invention, changing over of the machine to forming and fill bags of different lengths is simplified significantly and in a unique manner by maintaining the upper ends of all bags positioned on a common top datum line regardless of the length of the bags and by advancing the bags and by advancing the bags with their upper ends extending along the datum line during forming and filling. In addition, the various mechanisms which operate on the tope of the bags (such as the splitters 53 and 54, the dispenser 61, and the top sealing and cooling bars 63 and 64) are alined with and arranged along the top datum line so that, by moving the upper ends of bags of all lengths along the datum line, the machine may he switched over to run longer or shorter bags without need of raising and lowering the top operating mechanisms between each run.
In the present instance, the machine is capable of forming bags ranging in length from two inches to eight inches and is loaded with a web 30 of different width whenever a changeover is made to form bags which vary in length from those formed during the preceding run. To maintain the upper ends of all bags within the range lying along a common datum line, the elevation of the folding plow 47 is raised each time the machine is loaded with a narrower web to make shorter bags and is lowered each time the machine is loaded with a wider web to make longer bags.
As shown most clearly in FIGS. 2 and 6, the folding plow 47 is simply a flat V-shaped plate disposed in a downwardly inclined position immediately downstream from the guide roller 46 with the underside of the plow engaging the web 30 after the latter passes over the roller. The plow terminates at its lower end in a point 73 and coacts with a pair of upright pressing bars 74 on opposite sides of the point to depress the center of the web progressively downwardly and to fold the opposite side portions of the web progressively upwardly while pressing the side portions toward each other thereby to form the strips 49 as the web passes beneath the plow and between the folding rollers. Both the plow 47 and the bars 74 are suspended from a horizontal platform 75 which is mounted for vertical adjustment so that the plow and the rollers may be raised and lowered in unison when it is desired to change over the machine to form bags of different lengths. The two guide rollers 43 and 46 are journaled on the forward end of the platform and also are raised and lowered when the platform is adjusted.
To support the platform 75 for vertical adjustment, a cylindrical post 76 is telescoped slidably into a tubular sleeve 77 fastened within a hole 78 in the top of a base-like cabinet 79 (FIGS. and 26) and projecting upwardly from the cabinet along the rear side edge of the plow. An arm 80 fastened to and projecting forwardly from the upper end of the post overhangs the platform and is connected thereto by locking screws 81 (FIG. 7) which may be adjusted for purposes of locating the platform in a level position. Raising and lowering of the platform to any position between those shown in full and in phantom in FIG. 6.may be effected simply by turning an actuator in the form of a hand crank 83 (FIG. 5) to slide the .post upwardly or downwardly in the sleeve 77. The crank is conveniently accessible from the front side of the cabinet and is operably connected to a lead screw 84 by bevel gearing 85 housed within the cabinet. The screw projects upwardly through the top of the cabinet into a vertical bore 86 formed in the post and is threaded into a nut 87 which is fastened rigidly within the bore. Thus, rotation of the crank results in turning of the screw to slide the post 76 upwardly or downwardly in the sleeve 77 and thereby raise or lower the plow 47 to different elevations. A spring-loaded key 89 (FIG. 8) fastened to the sleeve and slidably fitted into a keyway formed in the post prevents the latter from turning when the crank is rotated.
To demonstrate the ease with which the machine may be changed over to handle bags of different lengths, let it be assumed that the machine initially has been set up to form bags 32 having a length of five inches out of a web 30 having a width of approximately ten inches. As the web moves beneath and is doubled upwardly by the plow 47, the fold 34 of the resulting strips 49 will be disposed level with the lower point 73 of the plow (see FIG. 3) and the upper edges of the strips will be drawn upwardly to and will extend along a horizontal line TL (FIGS. 3 and 6) which herein defines the top datum line. With the splitters 53 and 54, the dispenser 61, and the top sealing and cooling bars 63 and 64 properly set up relative to and positioned along the top datum line, the bags are formed, filled and closed in normal fashion as the web is drawn beneath the plow and as the machines cycle proceeds.
Now, if it is desired to adjust the machine to form and fill shorter bags 328 (FIG. 3), a narrower web of material is loaded into the machine and the plow 47 is raised from its original position by an amount corresponding to the difference in height of the bags 32 and the shorter bags 328, this amount being approximately equal to half the difference between the width of the original web 30 and the width of the narrower web. Because of the raised plow, the level of the lower fold of the narrow web will change as the web is doubled, but the edges of the web still will be drawn upwardly into precise alinement with the same top datum line TL. As a result, the shorter bags may be formed and filled without lowering the splitters 53 and 54, the dispenser 61, the top sealing and cooling bars 63 and 64, and certain other operating mechanisms as otherwise would be necessary if the plow were held at a constant level for bags of all lengths.
To make longer bags 32L (FIG. 3) from a web wider than the original web 30, the plow 47 is simply lowered from its previous position by an increment equal to the difference between the length of the long bags 32L and the length of the bags which were formed during. the preceding run. Such lowering of the plow causes folding of the upper edges of the wide web to the level of the top datum line TL as shown in FIG. 3 thereby doing away 6 and the term width has been used in reference to the horizontal dimension, it should be understood that these terms may be used interchangeably and do not necessarily imply that one dimension is greater than the other.
Contributing significantly to the ease with which the machine may be changed over to running bags of different sizes are novel mounting arrangements for the side sealing bars 50 and the cutter 55 to permit quick, convenient and precise adjustment of these elements along the path of the web simply by operating actuators connected to the elements. As shown most clearly in FIGS. 5 and 9, the side sealing bars are fastened to and disposed within a rectangular frame which is fastened at its lower end to a sleeve-like carriage 91. The latter, in turn, is telescoped slidably over an elongated tube 93 extending parallel to the web, one end of the tube being fastened releasably to one end plate of the cabinet 79 and the other end of the tube being fastened releasably to one end plate of a similar cabinet 94 disposed beneath the cutter. Fastened to and extending along the tube is a toothed rack 95 which meshes with a pinion 96 (FIG. 9a) housed Within the carriage and mounted to turn about a vertical axis. The pinion is geared to an operating crank 97 journaled in and projecting outwardly from the forward side of the carriage and, in response to turning of the crank, the pinion rotates in driving engagement with the rack to slide the carriage along the tube.
With this arrangement, the seal bars 50 may be adjusted to any desired position along the path of the web 30 simply by turning the crank 97 of the rack andpinion actuator. Preferably, a pointer 99 (FIG. 5) is attached to one end of the carriage 91 and runs along a calibrated scale 100 extending along the tube 93 thereby to indicate the position of the seal bars along the path at any given time.
In this instance, each side sealing bar 50 is reciprocated into and out of sealing engagement with the web 30 by a self-contained actuator in the form of a pneumatic ram 101. As shown in FIG. 9, each ram comprises a cylinder 103 slidably receiving a plunger 104 which is connected at its free end to one of the sealing bars, the latter extending substantially perpendicular to the plunger. In response to the flow of pressurized air into and out of the cylinders, the plungers are reciprocated back and forth to shift the bars toward and away from each other and into and out of sealing engagement with the web. Air flows to the cylinders through conduits (not shown) from a pressure source 105 (FIG. 5) housed within the cabinet 79 and is controlled by solenoid-actuated valves (not shown) which are operated in timed relation with the advance of the Web to cause shifting of the seal bars toward the web each time the latter dwells. The air conduits extend from the cabinet 79 to the cabinet 94 through a rectangular duct 106 (FIGS. 9 and 26) extending horizontally between the upper rear corners of the cabinets and interconnecting the two. The cabinets are further interconnected by forward and rear frame members 107 (FIG. 26) extending between the lower corners of the cabinets with a diagonally inclined shield 109 anchored to the forward frame member and the duct to prevent debris from collecting beneath the machine.
Advantageously, the side sealing bars 50 are long enough to form the seals 51 on the longest bags which are formed by the machine and thus the machine may be changed over to run bags of a different length without 5 raising or lowering the bars between runs. In many instances, however, it is desirable to locate the plungers 104 at the vertical centers of the seals so that the sealing pressure exerted by the rams 101 will be distributed uniformly over the length of the seals. For this purpose, the rams are mounted for vertical adjustment relative to both the frame 90 and the seal bars to enable centering of the plungers along the seals when the machine is changed over to run longer or shorter bags.
To mount the rams 101 for vertical adjustment relative to the frame 90, the latter is formed with elongated vertical slots 110 (FIG. through which the plungers 104 project inwardly toward the seal bars 50. Each ram is secured to the outer side of the frame by a clamping plate 111 (FIG. 9) which may be bolted in various vertical positions on the frame to enable raising and lowering of the ram with the plunger moving within the slot 110. An elongated connecting strip 113 is attached to the free or inner end of each ram and is formed with a vertically extending tongue which slidably interfits with a groove formed in a similar connecting strip 114 fastened to the outer side of each seal bar, the two opposing strips being releasably fastened together by screws 115. Centering of each plunger 104 on the vertical center of the seals 51 may be accomplished by loosening the screws 115 to release the plungers from the seal bars and holding the latter at a desired level while the rams are released from the frame by loosening of the clamping plates 111. After the rams have been raised or lowered to center the plungers vertically with respect to the bags of the next run, the pairs of connecting strips 113 and 114 and the plates 111 are reclamped to anchor the rams and the bars in the desired positions.
Like the sealing bars 50, the cutter is sufliciently long to sever bags of maximum length from the web and does not require vertical adjustment when the machine is changed over to run longer or shorter bags. Herein, the cutter comprises a swingable blade 116- (FIGS. 12 and 15) movable transversely of the folded web and across a fixed blade 117 with a scissors action after the web has been advanced between the two blades when the latter are separated. The swinging blade 116 is held under the pressure of springs 119 against one side of the upper end portion of an upright lever 120 of T-shaped cross-section, the lower end portion of the lever projecting downwardly into the cabinet 94 through a hole 121 (FIGS. 11 and 30) formed in a platform 123 which overlies and covers an opening 124 (FIGS. 10 and 26) formed in the top of the cabinet 94. Near its lower end, the lever is pivoted for back and forth swinging on a pin 125 (FIG. 12) rigid with and projecting axially from a circular disk 126 which is bolted releasably to one end wall of an underslung case 127 anchored to the lower side of the platform 123 and housed within the cabinet 94 in vertical alinement with the top opening 124.
To swing the movable blade 116 relative to the fixed blade 117, an air cylinder 129 (FIG. 12) is attached to the case 127 and includes a reciprocating plunger 130 pivotally connected to the lower end of the lever 120 and operable to rock the latter and the blade 116 about the pin 125 in response to the admission of pressurized air from the conduits in the duct 106 into alternate ends of the cylinder under the control of a solenoid actuated valve (not shown). Swinging of the movable blade 116 carries its cutting edge across the cutting edge of the stationary blade 117 to shear the web 30 along one of the seals 51, the latter blade being positioned to coaet with the cutting edge of the swinging blade and being fixed to one edge of a plate 131 upstanding from the platform 123. The web is guided between the two blades and is pressed against the cutting edge of the fixed blade during cut off by a spring metal strip 133 (FIG. 15) extending lengthwise of the blades adjacent the cutting edges.
In response to swinging of the movable blade 116, a flying splitter 134 (FIGS. 11 to 13) is swung upwardly from a normal position disposed between the upper edges of the folded web 30 to a raised position disposed out of the way of the swinging blade. The flying splitter is located within a gap defined by adjacent ends of the splitter bars 53 and 54 and is suspended from a shaft 135 journaled to turn on a top plate 136 supported above the plat form 12. As the web advances, the flying splitter holds the upper edges of the web spread apart as the latter passes between the blades 116 and 117 and through the gap between the splitters 53 and 54. During each dwell when the movable blade is swung through its cutting stroke, the splitter is rocked upwardly and out of the path of the lit blade by a crank 137 fastened to the lever 120 and connected by a link 139 to a crank 140 on the shaft 135.
In order to enable adjustment of the cutter 55 along the path when the machine is changed over to run wider or narrower bags, the platform 123 is mounted for back and forth sliding on the top of the cabinet 94, with the case 127 moving within the opening 124 during such sliding. As shown in FIGS. 12 and 14, roller 141 journaled on upright pins 143 depending from the platform are engageable with the side edges of the opening 124 to guide the platform and to keep the platform from shifting laterally on the cabinet 94. Quick and simple adjustment of the position of the platform and the cutter along the path may be accomplished by turning of an actuator in the form of a lead screw 144 which is threaded into a nut 145 detachably fastened to the forward side wall of the case 127. The screw extends through and is mounted rotatably in the end walls of the cabinet 94 and is adapted to be retated by a hand crank (not shown) fastened to one end of the screw. A pointer 146 (FIG. 12) is carried on the platform near the forward side edge thereof and runs along a scale on the top of the cabinet to indicate the distance of the cutter from the datum line DL. Since the flying splitter 134 also is carried by the platform 123, it is adjusted along the path with the cutter and always remains in the same working position relative to the cutter.
Advantageously, the feed rolls 66 and 67 also are mounted on the platform 123 for adjustment in unison with the cutter 55 so that a fixed horizontal spacing may be maintained between the rolls and the cutter in all adjusted positions of the latter. For this purpose, the rolls are journaled at their upper ends by the same top plate 136 carrying the splitter 134 and are journaled at their lower ends by the platform 123 so as to be movable with the platform. The rolls are spaced upstream from the cutter only far enough to establish sufficient clearance between the two to allow manual threading of the web 30 at the start of a run and, by adjusting the cutter and the rolls in unison, the clearance always remains fixed at a small value to utilize with maximum effectiveness the lateral support provided on the web by the rolls during severing of the bags from the web.
Intermittent rotative drive for the feed rolls 66 and 67 is produced by a power module housed within the cabinet 94 and including an electric motor 147 (FIG. 11) connected by an endless belt 149 to a gear box 150 having an output shaft 151 which mounts a variable throw crank 153. The latter is coupled by a pitman 154 to a second crank 155 fast on an internally splined horizontal sleeve 156 whose one end is journaled in the front end wall of the cabinet. An externally splined shaft 157 journaled on the underside of the platform 123 is telescoped slidably into the sleeve 156 and is coupled by means of an electromagnetic clutch 159 to gearing (not shown) housed within the casing 127 and rotatably coupled to the feed rolls 66 and 67. With this arrangement, the pitman 154 reciprocates up and down through one cycle in response to rotation of the output shaft 151 and the crank 153 through one revolution and acts through the crank 155 to oscillate the sleeve 156 and the shaft 157 back and forth about their axes. On the downstroke of the pitman, the direction of rotation of the shaft 157 corresponds to that necessary to rotate the feed rolls in a direction advancing the web 30 and, during the downstroke, the clutch 159 is energized to transmit the movement of the shaft 157 to the rolls to rotate the latter. Before the output shaft 151 completes one half revolution to start the pitman 154 through its upstroke, the clutch is de-energized to prevent the shaft 157 from driving the feed rolls reversely. The sliding fit between the splined sleeve 156 and the splined shaft 157 enables adjustment of the feed rolls along the path with the platform 123 while still maintaining a driving connection from the sleeve to the shaft and the feed rolls.
In setting up the machine, the throw of the crank 153 is adjusted to cause rotation of the feed rolls 66 and 67