US3727373A

US3727373A - Bag forming filling and sealing apparatus

Info

Publication number: US3727373A
Application number: US00219338A
Authority: US
Inventors: Leod N Mac
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-20
Filing date: 1972-01-20
Publication date: 1973-04-17
Anticipated expiration: 1990-04-17

Abstract

An apparatus for forming, filling and sealing a bag at a single station. A continuous strip of U-folded sheet material is fed transversely across the station intermittently in increments equal to the width of the completed bag. A single severing and sealing mechanism is positioned on the side of the station from which the material is fed to sever the sheet material and simultaneously seal both severed edges of the material between each feeding cycle. Suction means are provided for separating the free edges of the open end of the bag. Ram means may be provided for inserting an article into the open end of the bag. Closing means are provided for sealing the free edges of the bag after it is filled, and ejection means may be provided for removing the filled bag from the station.

Description

United States Patent 91 MacLeod m 3,727,373 51 Apr. 17, 1973 BAG FORMING FILLING AND SEALING APPARATUS Norman M. MacLeod, P. O. Box 4175, Chattanooga, Tenn. 37405 [76] Inventor:

[52] US. Cl ..53/183, 53/386 [51] Int. Cl. ..B65b 5/02, B65b 43/04, B65b 43/30 [58] Field of Search ..53/182, 183, 187, 53/386, 390, 384, 385, 29

[56] References Cited UNITED STATES PATENTS 3,619,973 11/1971 Bella ..53/l83 i 1 2 7, 11 I =1 A, 27 I EL-1 2+ 11 Primary Examiner-Robert L. Spruill Attorney-Harrington A. Lackey ABSTRACT An apparatus for forming, filling and sealing a bag at a single station. A continuous strip of U-folded sheet material is fed transversely across the station intermittently in increments equal to the width of the completed bag. A single severing and sealing mechanism is positioned on the side of the station from which the material is fed to sever the sheet material and simultaneously seal both severed edges of the material between each feeding cycle. Suction means are provided for separating the free edges of the open end of the bag. Ram means may be provided for inserting an article into the open end of the bag. Closing means are provided for sealing the free edges of the bag after it is filled, and ejection means may be provided for removing the filled bag from the station.

16 Claim, 4 Drawing Figures PATENTEDATR 1 H973 SHEET 3 [IF 3 BACKGROUND OF THE INVENTION This invention relates to a bagging or packaging machine, and more particularly to an apparatus for forming, opening and closing the bag automatically.

The formation of open-ended bags or envelopes by severing and sealing on opposite sides of the severed line of an intermittently moving folded strip of thermoplastic material is known in the art, as exemplified in the Messmer US. Pat. No. 3,197,936. The Messmer patent also discloses means for opening the mouth of the bag adjacent a loading platform for insertion of an article into the opened bag. However, the formation of the bag and the loading of the bag in the Messmer patent are performed at two different stations. Moreover, Messmer does not teach the closing of the bag or provide any means for ejecting the bag from the loading station.

Merritt US. Pat. No. 3,094,823 discloses that it is old to feed folded, flexible material intermittently with a positively driven feed roll by a pneumatic cylinder, rack and gear. Merritt further discloses that it is old to simultaneously transversely cut and seal the adjacent cut edges of plastic material.

The use of pushers or ram means for thrusting articles into the open mouths of the bags is known in the art, and it is also known to use suction heads or suction cups for opening the mouths of bags in order to fill the bags.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an apparatus which forms a bag from double-folded or U-folded sheet material, opens the mouth of the bag preparatory to filling with an article, closes and seals the mouth of the bag to completely enclose the article, and eject the sealed bag from a single forming station.

A U-folded continuous strip of sheet material, preferably thermoplastic material, is fed or transferred by a reciprocal transfer member moving transversely of the forming station from a first or trailing side of the station to a second or leading side, considering the direction of strip feeding. A heated wire element is reciprocably mounted along the trailing side of the station for movement through the strip material to simultaneously sever the inaterial along a transverse line and to seal the material on opposite sides of the severed line. The sealed and severed leading edge of the strip is then engaged and transferred by the transfer memberfrom the trailing to the leading side of the station where the leading edge is released by the transfer member. The severing and sealing mechanism is again activated to form the two sealed side edges of the bag. The fold in the sheet material forms the bottom or rear end of the bag, so that only the top or front edges of the bag are separated or free.

A pair of relatively movable suction heads are actuated to open the free edges of the bag, and if desired, ram means may be actuated to force an article on a loading platform in alignment with the bag between the open free edges into the bag. As the ram means is retracted, a transverse pressure bar is reciprocated 'to close the sides of the bag adjacent the free edges. While the pressure bar closes the sides of the free edge portions of the bag, a hot wire element is moved through the walls of the bag between the free edges and the pressure bar to simultaneously sever a small double-ply strip from the top of the bag and seal the remaining bag opening. After the pressure bar is retracted, a suction ejection head engages the bottom of the bag and removes it from the forming station.

One of the opening suction heads is preferably mounted to rotate about a transverse axis, while the other suction head is provided with a positive air jet directed toward the rotated suction head to remove the severed double-ply strip from the forming station.

After the filled bag is removed from the forming station, the feeding, forming, filling, closing and sealing cycles are then repeated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the apparatus made in accordance with this invention, with parts broken away;

FIG. 2 is a fragmentary rear elevation of the invention disclosed in FIG. 1 with portions broken away;

FIG. 3 is a fragmentary section taken along the line 33 of FIG. 2; and

FIG. 4 is an enlarged fragmentary section of the closing and sealingmechanism disclosed in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT The machine 10 made in accordance with this invention is provided with a stationary frame 1 1. Supported by the frame 11 is a substantially horizontal platform basically including a pair of flat parallel spaced platform members 12 for supporting the bag 18 to be formed at the single horizontal forming station 13. For purposes of reference, in FIG. 1 theleft end of the station 13 is the rear end, while the right end of the station 13 is-the front end. The longitudinal axis of the station 13 is parallel to the platform members 12 and extends from the rear end to the front end of the station 13.

Since the operator will stand in an area on the side of the machine 10 appearing at the bottom of FIG. 1, this side of the machine 10 will be referred to as the proximate'side, while the opposite side will be referred to as the remote side of the machine.

Mounted on appropriate frame portions on the remote side of the machine 10 for free rotary movement is a supply shaft 15 supportinga supply roll 16 of double folded or U-folded sheet material 17 from bag which the bag 18 is formed. The sheet material 17 is preferably of a flexible transparent type, such as polyethylene or polypropylene. v I The double-folded sheet material 17 is drawn from a supply roll 16 by and between a pair of positively transmission gear 26 fixed to the lower feed roll 20. In i this manner, both upper and lower feed rolls l9 and 20 are positively driven in the direction of the arrows'in 3 FIG. 2 to feed the double-folded sheet material 17 from the remote side of the machine toward the proximate side of the machine 10. Mounted between the drive gear 24 and the upper transmission gear 25 on the shaft of the upper feed roll 19 is a unidirectional, coil spring clutch 27 which engages the drive gear 24 with the shaft of the upper feed roll 19 on the upward stroke of the rack 23, but disengages the driving connection between the drive gear 24 and the upper feed roll 19 on the downward stroke of the rack 23.

Operatively engaging the upper end of the rack 23 is a transfer drive gear 28 fixed on one end of a drive shaft 29 supporting a drive toothed pulley 30 carrying a toothed endless transfer belt 31. The other end of the transfer belt 31 is carried around an idler pulley 32 rotatably mounted on the frame 1 1.

To the bottom leg of the belt 31 is fixed a cross-head 34 slidably mounted on guide rods 35 extending horizontally in the direction of the web feed and transversely of the bag forming station 13. The guide rods 35 extend entirely across the forming station 13. Reciprocably mounted for vertical movement in the cross-head 34 is a vertical post or rod 36. To the top end of the post is fixed a substantially flat elongated cam 37, and to the bottom end of the post 36 is fixed an elongated transfer suction head 40. The transfer head 40 is normally maintained in a position slightly raised above the platform members 12 by a coil spring 41 disposed between the cross head 34 and the cam 37. Moreover, the transfer head 40 is disposed transversely of the web feed, and consequently longitudinally of the forming station 13. A vacuum may be created in the transfer head 40 by a vacuum pump, not shown, through the vacuum conduit 42.

When the transfer head 40 is in its fully retracted position on the remote side of the station 13, the cam 37 engages the stationary cam roller 44 to depress the vertical rod 36 relative to the cross-head 34 and force the transfer suction head 40 down against the folded sheet material 17. When suction is applied through the hose 42, the transfer head 40 engages the web 17.

Since the vertically movable rack 23 drives both the

feed rolls

19 and 20 and the transfer pulley 30 and belt 31, the cross-head 34 and transfer head 40 are moved across the bag forming station 13 toward the proximate side of the machine 10, simultaneously with the positive feeding of the web 17 in the same direction by the

feed rolls

19 and 20. The stroke of the rack 23 is such that the transfer head 40 is moved from its solid-line position in FIGS. 1, 2'and 3 to the phantom position in FIG. 1. This distance corresponds with the desired width of the bag 18 to be formed. When the transfer head 40 is in the phantom position of FIG. 1, its motion stops with the suction still on to hold the leading edge 45 of the bag 18 at its aligned position on the proximate side of the station 13. The transfer head 40 stops by virtue of the rack 23 having reached the extremity of its upper stroke. Thus, the movement of the transfer head 40 as well as the positive feeding of the web 17 by the feed rolls l9 and 20 stop simultaneously.

Mounted on frame 11 on the remote side of the machine 10 between the station 13 and the feed rolls l9 and 20, is a severing and sealing mechanism 47. Severing and sealing mechanism 47 comprises an elongated hot wire 48 extending horizontally and transversely across the web path and spanning a distance slightly greater than the width of the folded web 17. The wire 48 is an electrical conductor supplied with electricity through the lead 49 to heat the wire to a sufficient temperature to quickly melt, sever and seal the plastic sheet material 17. The wire 48 is supported at its ends between a pair of plates 50 fixed on one end of the levers 51 pivotally supported by pins 52 upon the frame 1 1. The other end of the rear lever, or bell crank, 51 is pivotally connected by pin 53 to the piston rod of pneumatic cylinder 54 also supported upon a portion of the frame 11. A notch 55 is formed in the frame 11 transversely of and below the web path and aligned with the remote edge 56 of the bag 18 when stationary on the platform member 12in station 13.

Thus, after the leading edge 45 has come to rest at the proximate side of the forming station 13, automatic controls, not shown, cause actuation of the pneumatic cylinder 54 to pivot the levers 51 from their solid-line position disclosed in FIG. 2 down across the web 17 until the hot wire 48 has melted and severed the stationary folded sheet material 17, completely across its width, and descended into the notch 55. Simultaneously with the severing of the web, the heat from the hot wire melts the adjacent severed edges of the sheet material 17, which immediately cool to seal both edges on opposite sides of the cutting line. Thus, the trailing edge 56 of the bag 18 is sealed simultaneously with the leading edge of the folded sheet material 17, which upon the next cycle becomes the leading edge 45 of the bag 18 in the forming station 13. The hot wire 48 is immediately retracted automatically by any convenient control means, and raised to its inoperative position disclosed in FIG. 2 after the sheet material 17 has been severed and sealed.

After the severing and sealing mechanism 47 has been restored to its inoperative position, automatic means are provided to relieve the vacuum in the transfer suction head 40 to release leading edge 45. Simultaneously, the drive cylinder 22 is actuated 'automatically to retract the rack 23 thereby reversing the movement of the pulley 30 and belt 31 to return the cross-head 34 and transfer head 40 to their original starting position disclosed in FIG. 2, where the transfer head 40 remains stationary until the next cycle.

At this stage of the operation, the formation of the bag has been completed. The rear end of the bag 18 is closed by the original U-fold in the web material 17. The leading edge 45 was sealed on the previous cycle, while the trailing edge 56 was sealed in the current cycle. Thus, the front edges of the bag 18 remain free for later separation to form the mouth 58 of the bag (FIG.

Since the top feed roll 19 is provided with a unidirectional clutch 27, the rack 28 retracts without any reverse rotation of the feed rolls 1'9 and 20.

With the bag 18 thus formed upon the station 13, the bag 18 not only rests upon the two platform members 12, but also upon an ejection suction head 60, while the mouth of the bag 58 rests upon a tilting suction head 61. A vacuum is created in both of these suction heads 60 and 61 to hold the lower ply of the formed bag 18 in stationary position at the forming station 13.

Spaced above the tilting suction head 61 is an opening or lift head 62 mounted upon the piston rod 63 for reciprocal vertical movement in pneumatic cylinder 64. Lift head 62 is provided with suction passages 66 as well as positive air jets 67.

Mounted behind the lift head 62 is the closing head 69 carrying a transverse hot wire 70. Closing head 69 is fixed to the bottom of piston rod 71 positively reciprocal within the pneumatic cylinder 72. A transverse pressure bar 74 is carried by the closing head 69 for vertical reciprocal movement against the action of a coil springs 75.

As best disclosed in FIGS. 3 and 4, the tilting suction head 61 is mounted for rotary movement about its own longitudinal axis on stub shafts 78(FIG. 1), one of which is fixed to a crank arm or lever 79 pivotally con nected to the extremity of piston rod 80 positively reciprocal in the actuating cylinder 81. The tilting suction head 61 is adapted to pivot through an arc of approximately 90 100, between the horizontal position disclosed in FIG. 3 and the tilted position in FIG. 4.

Fixed on the frame of the machine in front of the forming station 13 is a loading platform 84 for receiving an article 85 of lesser dimension than the completed bag 18 and adapted to be inserted into the bag 18.

The operator of the machine 10 may be assisted in thrusting the article 85 rearward into the open mouth 58 of the bag 18 by insertion slide member or ram 86 fixed on slide head 87 adapted to be moved slidably along the guide rod 88 by piston rod 89 and pneumatic cylinder 90.

The loading platform 84 may also be provided with spaced side flanges or walls 91. Pivoted guide flanges or lips 92 may also be mounted on opposite sides of the rear end of the platform 84 in order to accurately align the article 85 with the mouth 58 of the bag 18.

The ejection head 60 is mounted for reciprocal sliding movement on guide rods 94 to move longitudinally of the station 13. The movement of the ejection head 60 is effected through link arms 95 and bell crank 96 pivotally connected together. The bell crank 96 is pivotally mounted by pin 97 to a stationary portion of the frame 11. The other end of the bell crank 96 is pivotally connected to piston rod 98 reciprocally moved by the pneumatic cylinder 99, which in turn is fixed to a portion of the frame 1 1.

After the bag 18 has been formed and is resting on the platform members 12, automatic controls are set in motion to actuate pneumatic cylinder 64 to depress the piston rod 63 and thereby the lift head 62 down upon the free edges constituting the mouth of the bag 18. Vacuum is created in the passages 66 to engage the top portion of thefree edge of the bag 18, while the lower ply is held by vacuum in suction head 61 as previously described. The pneumatic cylinder 64 is then reversed to retract the lift head 62, thereby opening the mouth 58 to the position disclosed in FIG. 3. The bag 18 is now in position for filling.

The operator places an article 85, such as a piece of cardboard wrapped with a pair of stockings, of dimensions slightly less than the length and width of the bag 18, upon the loading platform 84 between the guide walls 91. Preferably by depressing a switch, such as a switch on control box 105, the operator actuates the insertion cylinder 90 to cause the ram 86 to force the article 85 rearward between the guide lips 92 into the open mouth 58 of the bag 18. The piston rod 89 is extended until the article is completely within the bag 18 and the ram 86 has forced the front end of the article 85 behind the pressure bar 74. Automatic controls then reverse the actuation of the cylinder to retract the piston rod 89 and ram 86 to their original inoperative position disclosed in FIG. 3. I

The vacuum within the suction passages 66 of the lift head 62 is then removed and pneumatic cylinder 72 is actuated to force down the closing head 69. As soon as the pressure bar 74 engages the top ply of the bag 18, it forces the plies together and holds them in that position. Although the pressure bar 74 remains stationary in its holding position, nevertheless the closing head 69 continues downward compressing the spring 75 between the pressure bar 74 and the closing head 69. The closing head 69 continues downward causing the hot wire 70 to completely sever a narrow double-ply front end portion or strip 100 of the bag 18, simultaneously sealing the severed edges on both sides of the cut. Thus, the front end of the bag 18 is sealed closed with its contents 85 completely enclosed by all four edges of the bag 18. The severed double-ply strip 100 is held on the tilting suction head 61 by virtue of the vacuum created within it. Controls are then actuated to cause the pneumatic cylinder 81 to retract the piston rod 80 thereby rotating the tilting head 61 about its longitudinal axis from the horizontal position in FIG. 3 to the tilted position in FIG. 4. Vacuum is then removed within tilting suction head 61, while compressed air is forced through the air jet passages 67 of lift head 62 to blow the severed strip 100 away from the tilted suction head 61, causing the strip 100 to drop to a waste receptacle, not disclosed. 7

Air jet pressure is then removed from the passages 67, the pneumatic cylinder 81 reversed to restore the tilting head 61 to its original position, and pneumatic cylinder 99 actuated to extend the piston rod 98 and tilt bell crank 96 in the direction of the arrow disclosed in FIG. 3 to move the ejection suction head 60 rearward, thereby carrying the filled bag 18 rearward until vacuum in suction head 60 is removed and the bag slides by gravity down the inclined ramps 102, which are extensions of the platform members 12. The completed and filled bag 18 drops from the ramps 102 upon a conveyor or collection receptacle, not shown, or to any other desired deposit station. Controls are then operated to return suction head 60 to rest position and to actuate the rack cylinder 22 to resume thefeeding of the web 17 and to repeat the cycle.

It is believed that the operation of the machine 10 has been sufficiently described in connection with the description of the structural elements of the machine. The sequence of operation of the various pneumatic cylinders may be coordinated and effected by any convenient means, such as limit switches, sequence timers or a combination of the two, which could be partially located in the control box 105 (FIG. 3). Since such controls may be of any conventional construction or system, they have not been specifically disclosed.

If desired, an edge sensing mechanism may be employed to longitudinally align the edge of the web 17 with the desired direction of feed, such as an edge sensing mechanism incorporating a pneumatic sensor 107 (FIG. 2).

As previously described, the width of each bag 18 may be determined by the stroke of the rack 23, particularly for clear plastic material. Where the plastic material is sequentially imprinted, the stroke of the rack 23 may be controlled by a photoelectric eye 108 (FIG. 2) sensing an index bar or other indicator printed at spaced intervals longitudinally of the web 17.

The sealing hot wire 70 for sealing and closing the bag 18 may be provided with current through the electric supply line 109. 1

What is claimed is: 1. An apparatus for forming a bag, comprising: a. a forming station having a longitudinal axis and a transverse axis, a longitudinal leading side, a longitudinal trailing side, a front end and a rear end, b. means for feeding an elongated strip of material U- folded about the longitudinal axis of said strip,

transversely over said station so that the folded.

edge of said sheet material is adjacent said rear end,

0. means for transversely severing said folded sheet material on a line along the trailing side of said station,

d. said severing means including means for sealing the severed edges of said folded sheet material on both-sides of said line, to form a bag having free edges adjacent said front end,

e. opening means adjacent the front end of said station for separating said free edges to receive an article between said free edges and within said bag, and

f. closing means adjacent said front end for closing and sealing the free edges of said bag.

2. The invention according to claim 1 in which said feeding means comprises means for intermittently feeding said strip in increments equal to the width of each bag. i

3. The invention according to claim 2 in which said feeding means feeds the severed and sealed leading edge of the strip from the trailing side of the station to a position adjacent the leading side of said station, and means for stopping said feeding means after the leading edge of said strip is positioned adjacent the leading side of said station and until said bag has been removed from said station.

4. The invention according to claim 3 in which said feeding means comprises a transfer member adapted to grip the leading edge of said strip after it has been severed and sealed, means for reciprocably moving said transfer member transversely of said station between said trailing side and said leading side.

5. The invention according to claim 4 further comprising means for rendering said transfer member operative to grip said leading edge as said transfer member moves from the trailing side to the leading side of said station and to render said transfer member inoperative to release said leading edge at said leading side and to remain inoperative as said transfer member returns to said trailing side.

6. The invention according to claim 5 in which said transfer member comprises a suction head and means,

for creating a vacuum in said suction head.

7. The invention according to claim 5 further comprising a platform at said station for supporting said strip of sheet material, guide means perrnittin said transfer member to reciprocably move transverse y and slightly spaced above said platform, means for depressing said transfer member to engage the leading edge of said strip adjacent said trailing edge.

8. The invention according to claim 1 in which said sheet material is a thermoplastic sheet material, and said severing and sealing means comprises an elongated heated element and means for moving said element through said folded sheet material.

9. The invention according to claim 1 in which said opening means comprises first and second suction heads adapted to grip opposed exterior surfaces of said bag adjacent said free edges, means for creating vacuum in said suction heads, and means for relatively moving said suction heads toward and away from each other.

10, The invention according to claim 9 in which said closing means comprises a heated element extending transversely of said station proximate to and behind said suction heads, and means for reciprocably moving said heated element through said bag, said heated element being adapted to simultaneously sever and seal said bag along a transverse line adjacent said free edges.

1 1. The invention according to claim 10 further comprising air jet means in said second suction head directed toward said first suction head to remove the severed free edge portion held by said first suction head.

12. The invention according to claim 11 comprising means supporting said first suction head for rotary movement about an axis transverse of said station, and means for rotatably moving said first suction head about said rotary axis after the free edge portions have been severed.

13. The invention according to claim 1 further comprising bag ejection means for engaging the bag at said station and moving said bag after closure longitudinally rearward until said bag is removed from said station.

14. The invention according to claim 13 further comprising a platform at said station having an elongated slot, said bag ejection means comprising a suction head disposed in said elongated slot and adapted to grip the opposing surface of said bag, and means for reciprocably moving said suction head longitudinally in said slot.

15. The invention according to claim 1 further comprising a loading platform adjacent said front end for receiving an article in alignment with the opened free edges of said bag.

16. The invention according to claim 15 further comprising ram means for thrusting the article on said platform between the separated free edges of said bag and into said bag past said closing means.

Claims

1. An apparatus for forming a bag, comprising: a. a forming station having a longitudinal axis and a transverse axis, a longitudinal leading side, a longitudinal trailing side, a front end and a rear end, b. means for feeding an elongated strip of material U-folded about the longitudinal axis of said strip, transversely over said station so that the folded edge of said sheet material is adjacent said rear end, c. means for transversely severing said folded sheet material on a line along the trailing side of said station, d. said severing means including means for sealing the severed edges of said folded sheet material on both sides of said line, to form a bag having free edges adjacent said front end, e. opening means adjacent the front end of said station for separating said free edges to receive an article between said free edges and within said bag, and f. closing means adjacent said front end for closing and sealing the free edges of said bag.

2. The invention according to claim 1 in which said feeding means comprises means for intermittently feeding said strip in increments equal to the width of each bag.

6. The invention aCcording to claim 5 in which said transfer member comprises a suction head and means for creating a vacuum in said suction head.

7. The invention according to claim 5 further comprising a platform at said station for supporting said strip of sheet material, guide means permitting said transfer member to reciprocably move transversely and slightly spaced above said platform, means for depressing said transfer member to engage the leading edge of said strip adjacent said trailing edge.

10. The invention according to claim 9 in which said closing means comprises a heated element extending transversely of said station proximate to and behind said suction heads, and means for reciprocably moving said heated element through said bag, said heated element being adapted to simultaneously sever and seal said bag along a transverse line adjacent said free edges.

11. The invention according to claim 10 further comprising air jet means in said second suction head directed toward said first suction head to remove the severed free edge portion held by said first suction head.