US 3064827 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 20, 1962 w. T. BOSTOCK, JR, E'IAL 3,064,827
DIRECT BAG AND SHEET STACKER Filed April 16, 1958 6 Sheets-Sheet 1 1| Illh INVENTORS wit-LIAM T. Bos'rocx IR. DAvw E. JOHNSON yaw flj waw Nov. 20, 1962 w. T. BOSTOCK, JR., ETA]. 3,064,827
DIRECT BAG AND SHEET STACKER Filed April 16, 1958 6 Sheets-Sheet 2 lwvaw-roes WILLIAM T. Bcs'f'ock IR. DAVID E. Jouuson 5M i M- Nov. 20, 1962 w. T. BOSTOCK, JR., ETAL 3,064,327
DIRECT BAG AND SHEET STACKER 6 Sheets-Sheet 5 Filed April 16, 1958 IOI *- INVENTG RS WILLIAM 1805mm]: DAvlo E. Jar-vase Nov. 20, 1962 w. T. BOSTOCK, JR, ETAL 3,064,827
DIRECT BAG AND SHEET STACKER Filed April 16, 1958 6 Sheets-Sheet 4 INVENTOR$ WILLIAM BOSI'OCK JR, DAVID E. JoHNsoN Nov. 20, 1962 W. T. BOSTOCK, JR., EPA].
DIRECT BAG AND SHEET STACKER Filed April 16, 1958 6 Sheets-Sheet 5 o A] 0 (HM M 75 M W M 4 I O HIM MN 0 M f a? 32 W Iuvewvoes WlLUAM TI B srocxJ'lz DAVID E. J'oHusoN AT'rvs,
Nov. 20, 1962 w. T. BosTocK, JR, ETAL 3,064,327
DIRECT BAG AND SHEET STACKER 6 Sheets-Sheet 6 Filed April 16, 1958 INvEN-roRs WILLIAM E BosrocKJR DAVID EdHNSON O @9'%% y A-rrvs.
United States Patent Qfilice 3,064,327 Patented Nov. 29, 1952' 3,064,827 DIRECT BAG AND SFEET STACKER William T. Bostock, J12, Rochester, and David E. Johnson, Palmyra, N.Y., assignors, by mesne assignments,
to National Distillers and Chemical Corporation, a
corporation of Virginia Filed Apr. 16, 1953, Ser. No. 728,944 7 Claims. (-Cl. 2146) This invention relates to machines for stacking articles of flexible sheet material, such as bags.
It is a general object of the invention to provide a machine for stacking bags made from material such as limp, polyethylene film as the bags are received from the bag making machine.
Bags of such material are difficult to feed and stack due to the filmy, limp character of the bag material. The problem is greater at the high rates the bags are delivered from modern bag making machines. Conventional feeding and stacking apparatus, designed heretofore for articles or sheets of other stiffer material, and which employ belts and like expedients for transferring the articles, have proved unsatisfactory for handling bags of polyethylene film. Such stacking apparatus also is relatively complicated. Usually the bags are handled by several mechanisms such as for receiving, transferring and positioning before being stacked, eachor all such mechanisms employing belts or similar means for holding the bags.
It is now proposed to provide a stacking apparatus where the bag as it is fed from the bag making machine, is received and stacked in a single operation. Accordingly, it is an object to eliminate successive steps of handling requiring belts and like mechanisms for feeding and transferring.
Other more specific objects are to provide a stacker which is eflective to receive the bags at the high rate they are delivered; to place them fiat in exact register on the stack; to provide an accurate count of the bags as they are placed on the stack; and to convey the stack of bags when the number of bags in the stack has reached a preset count to another station where the stack may be further processed.
It is a primary object with this invention to provide a stacking apparatus for use in stacking sheets or bags delivered to the apparatus in a flat, suspended, substantially horizontal position.
It is an object to transfer the bags from the point at which they are received, in this suspended condition, and stack them on a conveying mechanism. Another object is to operate the conveying mechanism so that when the number of bags in a stack reaches a preset count the stack is shifted to leave space for a new stack to be formed.
Another object of this invention is to provide a completely automatic stacking apparatus for articles such as sheets or bags of limp, flexible film.
In a more limited aspect, it is an object to provide a conveyor positioned to receive the bags, and for operating the conveyor when the number of articles in a stack reaches a preset count for advancing the conveyor a step of sufiicient distance to shift the stack and prevent interference with succeeding bags which, if allowed to occur, would clog the machine. It is a related object to provide an intermittent drive for advancing the conveyor successively in steps of equal length. Another object is to provide means for adjusting the distance of advance of the conveyor.
Another object is to provide a friction drive for advancing the conveyor or other machine successively in steps of equal length.
Another object of the invention is to provide an apparatus for stacking bags as they are delivered from the bag making machine but which operates, except for timing, completely independently of the latter. A related object is to provide apparatus for transferring bags to a stack as they are received which is quick and so arranged as to operate freely whether the bags are received at a continuous or at an intermittent rate. Another object is to provide means for guiding the bags into exact register for good quality stacking.
Another object of the invention is to provide for guiding the bags in stacking by means which are adjustable to bags or other articles of different sizes. A related object is to provide for making such adjustments while the machine is operating.
Another object of this invention is to provide a stacking apparatus having few moving parts so that the apparatus will operate for many years with little maintenance. Another and a related object is to provide a machine which is capable of quality stacking, but is less expensive to make and maintain. Another object of the invntion is to provide a stacking apparatus which is characterized by its light weight and open design, so that it may be changed from one operation to another, if desired.
Other objects will appear from the following description taken in connection with the accompanying drawings, wherein:
FlGURE 1 is a side view of a stacking apparatus constructed in accordance with this invention;
FIG. 2 is a front view of the apparatus taken looking toward the left in FIGURE 1 and illustrates the front of the machine through which the bags are received;
FIG. 3 is a perspective view of atypical bag;
FIG. 4 is a top plan view of the machine;
FIG. 5 is a sectional view showing the guide assembly;
FIG. 6 is an enlarged sectional view taken substantially in the plane of line 66 of FIGURE 1, and illustrates the friction drive for driving the conveyor intermittently;
FIG. 7 is a view in elevation of the control panel shown only in outline in FIGURE 1;
FIG. 8 is a side view of a modified form of the stacking apparatus adapted for side delivery;
FIG. 9 is a front view of the modified form of the stacking apparatus shown in FIG. 8; and
FIG. 10 is a schematic view illustrating a portion of the bag machine for making and delivering bags to the stacking apparatus.
While the invention is susceptible of various modifications and alternative constructions, a preferred embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but, on the contrary, the in tention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention as expressed in the appended claims.
Turning now to the drawings, the stacking apparatus 13 includes a frame structure of angle iron members which is adapted for mounting on the production room floor adjacent to a bag making machine, a portion of which is shown schematically in FIG. 10, so as to receive the output of the machine directly. As shown in FIG- UR'ES 1-3, the articles may be bags 15 as in FIG. 3, of flexible, limp polyethylene film. This apparatus is primarily intended for use in stacking such articles when series delivered in a fiat, substantially horizontal position, and suspended, momentarily halted, in that position at the instant of delivery. Delivery may be achieved, for ex: ample, by severing the bag 15 with cut-01f knives, as shown in FIG. 10, from a continuous, horizontally fed web. In such an arrangement with a bag made from polyethylene film, the leading end 16 of the bag may have been heat sealed at a previous station and the sides of the bag either heat sealed or creased 17 if the bag is the type made from a continuous tubular web.
At the instant when the bag 16 is severed from the web, or released in some other manner, the bag is momentarily suspended in a hor zontal plane and at the receiving station 20 in the stacking apparatus 1%. As the bag travels in to the stacking apparatus, the lateral edges of the bag ride along guide means herein shown as strips carried by the guide 46. It has been found that with large bags, which are somewhat heavier, the guide strips assist in the support of the bag during delivery; but with small bags, they do not ride along nor rest'on the guide strips but travel iuto'the apparatus suspended without physical support, by their own inertia and by streams of air, shown in FIGURE 1, both above and below the horizontal body.
In accordance with this invention, upon the bags 15 being received at the receiving station 29 in the fiat condition and suspended, they are engaged by a vertically reciprocable stacker which has an initial position (FIGURES l and 2) over the bag 15 at the point of delivery and, moves downwardly to a position over the conveyor, where it stops at the end of its stroke and drops the bag on the conveyor 23. The return stroke of, the stacker positions it for the next bag, so that the stacker builds a stack by placing the bags on the conveyor as they are delivered.
Referring to FIGS. 2. and 4, for engaging and moving the bag 15 downwardly while maintaining it hat, the stacker 25 includes a substantially horizontal stacker foot 39. Power for operating'the stacker foot 3% is provided by an air cylinder 31 to which the stacker foot 39 is connected by the air cylinder shaft 32. In this arrangement the stacker foot 36, is reciprocated vertically so as to engage the bags on the downstroke and return on the upstroke to be positioned for the succeeding bag. Time for the return stroke is provided during the interval the succeeding bag is moving horizontally from right to left in FIGURE 1 towards the delivery position, when its forward movement is momentarily halted and it hangs suspended for the instant while the cut-0E. knives act. The motion of the stacker foot is timed with the receipt of the bags in the apparatus, and means controlled by a timing shaft 34- are provided for this purpose; 7 As illustrated, the stacker foot 3t) is in the form of a grid or open framework of members so as to decrease air resistance and to limit the turbulence created upon vertical movement of the foot.
Further in accordance with the invention, the conveyor 28, which in the present instance is an endless conveyor, is stopped beneath the receiving station for the bags so that the successive bags placed on the conveyor by the stacker'foot build into a stack. The counter 33 is provided for obtaining an accurate count of the bags in a stack, and. this counter 33 may be operated in any desired manner, as by means of. a poppet cam 34 on the timing shaft 34. For conveying the stacks of articles from below the receiving station when the number of articles in a stack on the conveyor reaches a preset count, the conveyor is advancedby means of an intermittent drive 35 a distance such as to leave space on the conveyor 28 for the formation of a new stack.
Stacker and Guide Assembly In keeping with an important aspect of the invention, in the single stage operation of forming thest ack on the conveyor 28, this apparatus provides a guide 40 for the bags which is effective in conjunction with the stacker to'insure exact register of the bags as they are placed on the stack. As shown in'the drawings, particularlyre ferring to FIGURES 1, 2 and 5,'the stacker is mounted on top of the frame, and in the preferred form of the invention shown in these figures, the stacker foot 30 is mounted for substantially vertical movement from an initial position over the receiving station for the bags to a position over the stack on the conveyor 28. For. this purpose the stacker foot 30 is mounted by means of a horizontal plate 42 on the lower end of the air cylinder shaft 32. This plate 42 is carried by the air cylinder shaft 52 and a guide rod44 which are connected together at their upper ends by a tie bar 45. For mounting the air cylinder 31 it is rigidly fastened in an erect position to a narrow mounting bar or plate 46 which extends across the top of the machine spanning the. top angle members 47, 48. As shown in FIG. 4, these latter angle members 47, 48 are each provided with a lengthwise slot 49, 5t and the mounting plate 46 for the air cylinder 31 is anchored in place on the top of the angle members by means of upper and lower clamp ing bars 51, 52 fastened together by cap screws 53 which pass through the slots 49, Lengthwise, slots 55, 56 are. provided in the air cylinder mounting plate 46 to allow longtitudinal adjustment of the latter, which permits adjustment of the stacker 25 sidewise of the frame of the. machine. The stacker foot 30, and plate 42 which fastens the same to the air cylinder shaft 32 and guide rod 44 are connected by cap screws 58. In this arrangement, the guide rod 4-4 and-air cylinder shaft 32 are arranged parallel and the guide rod is journalled for vertical movement in the air cylinder mounting plate 46. The air cylinder shaft 32ris connected. to. a piston (not shown) slidable longitudinally of the. air cylinder 31.
As shown in FIGS. 4 and 5, the stacker foot 30, which engages the bags 15 as they are received at the receiving station 26, is constructed as an open frame work of longitudinal members 60 and cross-members 61 so as to reduce air resistanceand limit turbulence.
At the leading edge of the foot 30, that is to say, theedge adjacent to the bag machine, the foot carries. a transverse rod having. upturned ends 63 which extend a sub stantial distance on both sides of the longitudinal mem: bers 6t) defining the lateral'edges of the foot. It has been found that with such a provision bags of varying widths may be stacked without adjusting the apparatus or changing the foot for one of different size. 'Thus with the foot 30 as depicted in FIG. 4, bags of amaximum size somewhat wider than the foot may bestacked in the apparatus as well as bags substantially narrower than the narrow body of the foot itself.
Ithas alsobeen found that bags of different lengths may be stacked with the apparatus of this, invention. By using different sizesv of stacker foot, however, a wider range of bag sizes may be stacked one. given machine. Thus, for example, by using two sizes of stacker foot, one having a width of about 6.5 and a length about 20" and the other having. a Width of about 4" and a length about 20", the machine is. effective for stacking bags varying in length from about 4" to as long as27 in length, and in width from about 2 to as wide as 16".
The air cylinder 31 is operated to reciprocate thestacker foot 30 in time with the receipt of the bags 15. This is accomplished by a control operated fromthetiming shaft 32 mounted horizontally betweenthe side uprights of the machine frame. The said timing shaft 34 is mounted within bearings 66, 6 7 on the, side; frame members and includes a sprocket 68 for driving from a chain (not shown) driven by the bag making machine.- Thus the timing shaft 34 isdriven inaccord wlththe delivery of bags from the bag makingmachine and the operation of the stacking apparatus 10 thus is. timed with the operation of the bag making machine. For controllingrvarious valves including a valve 70 (FIG, 7) regulating the supply of air to the air cylinder 31 for the stacker 25, the timing shaft 65 is provided with a poppet cam 34 (FIGS. 2 and 7). A control panel 72 is used for mounting the valve 70, and this panel is fastened on the frame in a location that allowsthe end of the timing shaft 34' to project through a bush 74 mounted in the panel. The poppet cam 34 is mounted on the end of the timing shaft 34' in front of the panel 72. Adjacent to the poppet cam 34 and mounted on the panel is a timing assembly 75 including an adjustable timing plate 76 and a timing lever 77. The poppet cam 34 has a land on its face, and when rotated by the timing shaft 34' operates as a lifter to momentarily open a plurality of poppet valves 78 mounted on the timing plate. These poppet valves 78 are spring loaded to a normally closed position. They are connected by means of air lines to the valve 71} for the stacker air cylinder. The valve 70 is controlled by a piston so that it is shifted upon actuation of the poppet valves 78, to control the supply and exhaust of air to the air cylinder 31. Air under pressure is supplied to the valve 78 from an air line 8% and pressure and exhaust lines 81, 82 for the air cylinder 31 are connected to the valve 79. Oilers S5, filter 86, and pressure regulators 37 are mounted on the panel 72 and are connected in the air line 89.
While other arrangements may be used, for exemplary purposes, the counter 33 is also mounted on the panel 72 so as to be operated by the poppet cam 34 as by an arm 89.
Turning now to the construction of the guide assembly 40 for obtaining exact register of the bags placed on the conveyor 28, the guide assembly is shown in FIGS. 15 where the machine is arranged for straight through delivery. The guide assembly 40 is mounted at the receiving station Where the bags are received. In comprises a pair of vertical plate members 96, 97 which are movable simultaneously inwardly and outwardly so as to obtain a spacing established depending upon the width of the bags to be stacked. These vertical plate members 96, 97 are fastened on the outer sides of a pair of bag support rails 98, 99. Preferably these rails 98, 99 are rectangular in cross section and made of wood so as to be non-conducting. For fastening the vertical plates 96, 97 to the wooden rails 98, 99 screws or the like may be used. The vertical members at their bottom edges slidably rest on top of the conveyor belt 28 which may be moved thereunder, and support the guiding apparatus 40. On the rail supports 98, 99 there are mounted narrow, flat bag support strips 1h5,'106 which may be made, for example, of material such as rigid polyethylene. It has been found preferable to space the facing edges of these bag support strips 1135, 1116 about the width of the bag to be stacked. While some overlap is usually desirable, not more than about a half inch overlap can ordinarily be allowed. As shown in FIG. 4, the horizontal bag support strips 105, 106 are mounted about the width of the bag 15 shown in phantom outline to be stacked by means of the apparatus, and the bag rides in on these strips.
For simultaneous movement inwardly and outwardly of the members 96, 97, so as to obtain a desired adjustment of the guide strips 105, 1136 for a given bag width, the rails 98, 99 and the vertical plate members 96, 97 are fastened to precision screws 108, 109 mounted in bearings 11%, 111 so as to be supported for rotation and transversely of the machine frame. The screws 108, 109 have threads of opposite hand from the center of the screw outward to the opposite ends. Nuts 112, 113 threaded on the screws 108, 1439 are connected by means of rods 114, 115 to the rails and plate members. Thus by rotating the screws 1118, 109, as by means of a manually operated crank 116, the rails 98, 99 and plate members 96, 97 are shifted inwardly or outwardly depending on the rotation of the crank 116. The screws 198, 109 are connected by means of sprockets 117, 118 and a chain 119 so that when the screw 108 which is fastened to the crank 116 is turned, the screw 199 will turn a like amount. Thus the guide assembly members are moved evenly inwardly and outwardly.
As shown in FIGURE 1, the bag 15 when received is positioned slightly, perhaps an inch or so above the upper surface of the bag support strips 105, 106 and hangs suspended at the time of receipt. Obtaining this flat condition at the instant of delivery from the bag machine may be facilitated by providing streams of air 119' above and below the bag 15. Such streams of air may be supplied by nozzles mounted adjacent the stacking apparatus on the bag machine as shown in FIG. 10.
To discharge any static charge carried by the bag being stacked, the wooden rail supports 98, 99 each carry a static bar 1211, 121 by means of brackets 122 adjacent each end of the bars. These brackets are mounted on respective support plates 124 and provide an adjustable mounting for positioning the static bars toward and away from the path of movement of the stacker foot 30. The static bars 129, 121 include a row of alined emitter points 125, 126 and mounted on each static bar is a ground rod 127, 128 which is fastened to the respective static bar by supports 129 carried at each end of the rod. It will be noted that the ground rods 127, 123 may be positioned about the static bars 121 121 for adjusting their position relative to the path of movement of the stacker foot 31 and the bag 15. By appropriate adjustment of the static bars and the ground rods the static charge on the bags may be discharged.
Conveyor and Conveyor Drive ltlechanism After a preset number of bags have been placed in a stack on the conveyor 2-8, the present invention provides an intermittent drive for advancing the conveyor a distance such as to carry the stack from beneath the stacker 25 and away from the receiving station 211 so as to leave a space on the conveyor for forming a new stack of bags. Power to move the conveyor 28 in the present instance is obtained from an air cylinder 131} (FIGURE, 1) mounted on the frame, via an intermittent drive transmission 35, and a chain drive coupling the transmission shaft 132 and the drive shaft 133 for the conveyor 28. The air cylinder 13 is mounted on an air cylinder mounting plate 135 fastened on the frame, and extends horizontally. A piston (not shown) longitudinally slidable within the air cylinder 13% is mounted on the air cylinder shaft 137. Power is supplied from the air cylinder 130 to the transmission shaft 132 by a horizontally drivable rack connected by a pin and slot coupling 141 to the air cylinder shaft 137. The other end of hte rack 14% is supported between a pinion and a roller 142 in the intermittent friction drive 35. The drive 35 is effective to transfer motion in one direction of the rack 140 to the transmission shaft 132, which by means of a chain and sprocket drive 143 operates the conveyor 28. Herein, the rack drives in its return stroke.
The intermittent friction drive transmission 131, as shown more particularly in FIG. 6, includes the pinion 145 which meshes with the rack 14%. A one-way clutch 146 driven by the pinion 145 is connected to the transmission shaft 132. This one-way clutch is mounted within a bearing 147 so that it is rotatable about the transmission shaft. While the details of the one-way clutch 146 are not shown, it will be understood that a conventional roller and gravity pawl clutch or other equivalent clutch may be used, which runs free and silent one way and grips instantaneously the opposite way. With such an arrangement rotation of the pinion 145 in one direction is transferred to the transmission shaft 132 while its opposite motion is not so transferred.
Both the timing of the operation of the conveyor air cylinder 130 and thus the timing of the advance of the conveyor 28, and the distance of advance of the conveyor each time it is operated, may be controlled in any desired manner. It is preferred to use a solenoid operated control valve 150 mounted on the control panel and connected in a circuit actuated by the counter 33. Accordingly, the control valve 150 may be operated when the number of bags in a stack has reacheda preset count, so as to move the conveyor a predetermined distance.
i The distance the conveyor advances is determined by the length of stroke of the piston of the air cylinder 13% and the rack 140 connected thereto. in keeping with the invention, control means are provided for adjusting the stroke. For this purpose a trip bar 152 is mounted on the rack 14%}, which bar includes a horizontal arm 153. The end of the arm 153 moves in a horizontal path adjacent the back side of the control panel and is adapted to strike a microswitch 157 mounted behind the control panel. This microswitch is used to control the solenoid of the air valve 150 regulating the air supply to the conveyor air cylinder 130. The position of the microswitch 157 is adjustable horizontally the length of the slot 138; in the control panel. With this arrangement the microswitch 157 may be used to reverse the supply of pressure air to the conveyor aircylinder 136 when hit by the arm 153 of the trip bar, thus setting with nicety the length of the stroke. A thumbscrew 159 is accessible on the front of the control panel, and may be loosened to allow adjustment of the mount for the microswitch 157 along the slot.
It will be seen that the present stacking apparatus employs no belts for feeding, transferring or delivering the articles, bags or sheets, either at the receiving station 29 to assist in stacking the articles, or from the stacker to a discharge point. An endless conveyor 28 is provided which is driven ointermittently to transfer the completed stacks as the bagsare received from the bag making machine, but the operation of the latter is simple and not likely to raise problems of clogging or the like. It will be readily evident that the conveyor 28 may extend to a loading platform or second conveyor for transferring the stacks to stations for packaging and shipment.
Referring now to FIGS. 8 and 9, a modification of the invention is there depicted. In this form the stacking apparatus is arranged for side delivery rather than straight through delivery (FIGURES 1-5) of the stacked 'bags. Thus, the conveyor 17% is arranged so that it extends perpendicular to the path the bags travelin delivcry to the stacker.
The stacker foot 171 is mounted so that it transfers the bag 15.1ongitudinally in the directionof its delivery as well" as downwardly onto the conveyor 17% to insure that the bags do not overhang the edge of the conveyor. Referring to FIG. 8 it will be observed that atthe instant of delivery the trailing end of the bag extends a short dis tance from the frame of the stacking apparatus. This distance maybe unavoidable clearance distance between the stacking apparatus and the final mechanism. of the bag making machine, for. example, the cut off knives. With side delivery from the stacking apparatus, that is to say, delivery on a conveyor travellingv in a directionperpendicular to the. direction in which the bags are moving when they enter the stacker, it is necessary thatthe bags be completely withinthe framework andnot overhanging the edge of theconveyor 17th, so that they can be moved from the machine or the conveyor without hitting the frame members at the side of the machine. Accordingly, as shown in FIG. 8, the axis of the stacker air cylinder 172 and its. shaft 173, and the parallel guide rod 174 isarranged atabout 15 from the vertical in a direction such that the stacker foot171 shifts the bag forwardly or further along the direction of delivery. Thus it is transferred from right to left as shown in FIG; 8"from the dashed position to a position onthe conveyor. With this arrangement the stacker foot 171 is horizontal as with the form of the invention shown in FIGURES l6 and its movement is timed in accord with the series receipt of the bags 15, as previously described.
It will be evident that the same control mechanism may be employed and the same drive for the conveyor '28, with the change in mounting for the conveyor and g its drive made necessary by the reorganization to provide the desired side delivery.
, We claim as our invention:
1. In a stacking apparatus for articles of limp flexible sheet material, such as polyethylene bags, said articles being delivered at the end or" a lineal path to the receiving station of the stacking apparatus in a flat condition and suspended in a substantially horizontal plane, the combination comprising, a normally stopped horizontal conveyor mounted below the receiving station and extending in a directionsubstantially perpendicular to said lineal path for side delivery of the articles from the stacking apparatus upon movement of the conveyor, a vertically movable stacker mounted above the receiving station and vertically reciprocable on an axis tilted about 15 from the vertical and in the same direction as the lineal path so as to engage the articles on the downstroke and shift them longitudinally from the place of delivery to a stack on the conveyor, and return on the upstroke to be positioned for the succeeding article, means for operating the stacker in time with the receipt of the articles, and means for moving the conveyor a distance such as to carry'the' stack from under the stacker when the number of articles in the stack has reached a preset count.
2. in a stacking apparatus for articles of limp, flexible sheet material, such as polyethylene bags, said apparatus having a frame, the combination comprising, a substantially horizontal conveyor mounted on the frame and'i'n'ovable to deliver stacks of articles in alinear' path leaving the frame from the side, said articles being received through the front of the frame at a receiving station above the conveyor in a flat condition and suspended in a substantially horizontal plane, a stacker mounted on the frame over the receiving station and conveyor and including a vertically reciprocable rectangular foot comprising members arranged in a horizontal open framework, said foot having an initial position above the receiving station, a member carrying said foot, means for mounting said member on. the framefor longitudinal movement on an axis tilted about 15 from the vertical and toward the direction of receipt of the articles, and means for recipro cating said member so that the stacker foot engages the articles on the downstroke and places them on the C011? veyor and returns on the upstroketo be positioned for the succeeding article.
3. In a stacking apparatus for articles of limp, flexible sheet material, such as polyethylene bags, said articles being series delivered at the end of a lineal path to the receiving station of thestacking apparatus in aflat condition and suspended in a substantially horizontal plane, said apparatus having a. frame, the combination cornprising, a platforrnmounted on the frame beneath the receiving station, and a stacker mounted in a fixed posi tion on the frame above the receiving station andplat: form, said stacker including a vertically reciprocable foot comprising members arranged in an open framework, means for reciprocating thefoot in time with the delivery of the articles so that the stacker foot engages the articles on the downstroke and builds a stack on the platform and returns on the upstroke to be positioned for the succeeding article, the axis of movement of the foot being inclined about 15 to the vertical and in the direction to carry the bags further into the apparatus from the receiving station. a
4. In a stacking apparatus for articles of limp, flexible sheet material such aspolyethylenebags, the combination comprising, a substantially horizontal conveyor for moving stacks of articles from the apparatus along a lineal path, means for delivering said articlesto a receiving station above the conveyor in a flat condition andsuspendcd in a substantially horizontal plane, said delivering means including guide means having horizontal members mounted parallel to the path of delivery of the articles and adjacent the edges of the latter at a level below the plane of delivery thereof so that the articles are received over the members, and nozzles ror directing air horizontally adjacent and parallel to said members to assist in delivering said articles, a stacker mounted over the receiving station and conveyor including a vertically reciprocable foot having an initial position above the articles as they are received and movable to engage the articles on the downstroke and place them on the conveyor in a stack and return on the upstroke to be positioned for the succeeding article, means for operating the stacker foot in time with the receipt of the articles, said guide means including vertical members associated with said horizontal members straddling the path of movement of said stacker foot for alining the stacked articles, and means for adjusting the spacing of said members to about the width of the article.
5. In a stacking apparatus for articles of limp, flexible sheet material, such as polyethylene bags, the combination comprising, a substantially horizontal conveyor for moving stacks of articles from the apparatus, means for delivering said articles to a receiving station above the conveyor in a flat condition and suspended in a substantially horizontal plane, said delivering means including guide means having horizontal members mounted parallel to the path of delivery of the articles and adjacent the edges of the latter at a level below the plane of delivery thereof so that the articles are received over the members, and nozzles for directing air horizontally adjacent and parallel to said members to assist in delivering said articles, and a stacker mounted above the receiving station and conveyor and including a vertically reciprocable foot comprising members arranged in an open horizontal framework so as to provide substantially turbulent free vertical movement of said foot, and means for reciprocating the foot in time with the receipt of the articles so that the stacker foot engages the articles at the receiving station in the course of a continuous downstroke for moving said articles downwardly onto the conveyor and returns on the upstroke to be positioned over the receiving station for the succeeding article.
6. In a stacking apparatus for articles of limp, flexible sheet material such as polyethylene bags, the combination comprising, a substantially horizontal conveyor for moving stacks of articles from the apparatus along a lineal path, means for delivering said articles to a receiving station above the conveyor in a fiat condition, a stacker mounted over the receiving station and conveyor and including a vertically reciprocable foot, means for operating the stacker foot in time with the receipt of the articles to engage the articles on a downstroke and place them 10 on the conveyor in a stack and return on the upstroke to be positioned for the succeeding article, and means associated with said delivering means for guiding the articles into position at the receiving station, said guide means including vertical members straddling the path of article delivery, horizontal fixed guide strips mounted on said members at a level below the plane of delivery of the articles, and means for adjusting spacing of said guide means so that said guide means is spaced apart to lie adjacent the longitudinal edges of the article material ereby to adapt the stacking apparatus to receive articles or" ditierent width, said strips being positioned at the edges of the articles for guiding the latter, said stacker toot comprising members arranged in an open horizontal framework fitting between said guide means so as to provide substantially turbulent free vertical movement of said foot.
7. in a stacking apparatus for articles of limp, flexible sheet material, such as polyethylene bags, said articles being delivered at the end or" a lineal path to the receiving station of the stacking apparatus in a flat condition and suspended in a substantially horizontal plane, the combination comprising, a platform beneath the receiving station; guide means carried over said platform at said receiving station straddling the article delivery path and spaced apart to lie adjacent the longitudinal edges of the article material to guide the latter into stacking position; and a stacker mounted above the receiving station and platform and including a vertically reciprocable foot and means for reciprocating the foot in time with the receipt of the articles, said foot comprising members arranged in an open horizontal framework fitting between said guide means so that the limp, flexible material is engaged by the stacker foot and uniformly moved downwardly onto the platform without the creation of substantial air turbulence from the movement in either direction of said stacker foot.
References Cited in the file of this patent UNITED STATES PATENTS 1,364,562 Laughton Jan. ,4, 1921 1,880,077 Dill et al. Sept. 27, 1932 1,881,824 McNamara Oct. 11, 1932 2,164,371 -Ajello July 4, 1939 2,294,273 Buxbaum Aug. 25, 1942 2,315,003 Martin Mar. 30, 1943 2,506,550 Morrison May 2, 1950 2,848,820 Wallin ,V Aug. 26, 1958