US3427780A

US3427780A - Bag opening and closing machine

Info

Publication number: US3427780A
Application number: US599288A
Authority: US
Inventors: Philip Bock
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-12-05
Filing date: 1966-12-05
Publication date: 1969-02-18
Anticipated expiration: 1986-02-18

Description

Feb. 18, 1969 P. BOCK 3,427,780

BAG OPENING AND CLOSING MACHINE Filed Dec. 5. 1966 Sheet 1 ors 2 7 9 2 L I9 /27 I9 IO 06 93il 4 v 23 3 7s 27 I ATTORNEY Feb. 18, 1969 P. BOCK 3,427,780

BAG OPENING AND CLOSING MACHINE Filed Dec. 5, 1966 Sheet 2 of 5 INVENTOR. PHILIP BQCK A TTORNE Y F eb. 18, 1969 P,

B

3,42 7,730

BAG OPENING AND CLOSING MACHINE 67 2 .8. INVENTOR.

PHILIP BOCK BY 69 ATTORNEY Feb. 18, 1969 P. Bock 3,427,780

BAG OPENING AND CLOSING MACHINE Filed Dec. 5, 1966 Sheet 4 of 5 I4 26 78 IO INVENTOR. PHILIP BOCK 1 v I ATTORNEY Fb. 18, 1969 P. BOCK 3,427,780

BAG OPENING AND CLOSING MACHINE Filed Dec. 5, 1966 Sheet 5 of a POWER HEATER SWITCH 7 S IT L A;- W CH MOTOR PUMP CONTROLLER SWITCH v v Jl H J r' 66 MOTOR VACUUM PUMP LL]. K]. H.

FFILLING UNIT L INVENTOR. fig. 46. PHILIP BOCK \9 A TTORNE Y United States Patent 3,427,780 BAG OPENING AND CLOSING MACHINE Philip Bock, 14025 Crenshaw Blvd., Hawthorne, Calif. 92050 Filed Dec. 5, 1966, Ser. No. 599,288 U.S. C]. 53-63 Int. Cl. B65b 57/06, 43/26 This invention relates to the art of package filling and more particularly to a facility or device for manipulating bags, pouches and envelopes preparatory to being filled and for closing such receptacles after the filling thereof has been completed.

The principal object of the invention is to provide a machine operating in a time sequence to take a bag or envelope from a supply stack, move it to a position at which the filling is to occur, open the bag or envelope to permit filling with the desired contents, then closing the bag and finally delivering it to a point of disposal and thereafter repeating the cycle.

Other objects of the invention include the provision of a machine in which the foregoing principal objective is realized in practice, which is capable of use with either gusseted or non-gusseted receptacles, which is susceptible of adjustment to accommodate a variety of sizes of bags and envelopes, which includes bag contacting parts which are readily kept in a sanitary condition and which is sus ceptible of use with a wide variety of batch dispensing devices for filling individual bags or envelopes as they are presented for reception of the dispensed contents.

With the foregoing objects in view, together with such additional objects and advantages as may subsequently appear, the invention resides in the parts and in the construction, combination and arrangement of parts described, by way of example, in the following specification of a presently preferred embodiment of the invention, reference being had to the accompanying drawings which form a part of said specification and in which drawings:

FIG. 1 is a side elevational view of a presently preferred embodiment of the invention,

FIG. 2 is a top plan view of the embodiment shown in FIG. 1,

FIG. 3 is an enlarged scale, somewhat diagrammatic top plan sectional view taken as on the line 33 of FIG. 1,

FIG. 4 is an end elevational view of the right hand end of the machine shown in FIG. 1, a portion of the machine being broken away in the general area indicated by the staggered line 44 in FIG. 1,

FIG. 4a is a side elevational view of the bag opening, closing, and sealing instrumentalities of the machine as viewed from the right hand side of FIG. 4,

FIG. 5 is a bottom plan view of the top plate component taken on the line 5-5 of FIG. 1,

FIG. 6 is a perspective fragmentary view of the bag transporting means,

FIG. 7 is an enlarged, fragmentary elevational view of the bag gripping and sealing means as viewed in the same direction as in FIG. 4,

FIG. 8 is a fragmentary bottom plan view taken on the line 8-8 of FIG. 1,

FIGS. 9 through are a series of top plan views showing various stages of progression of the bag handling means during a cycle of operation of the machine, and

FIG. 16 is a diagram showing the various circuits, electric, pneumatic, and vacuum, of the operating means of the machine.

In the following specification and in the claims, the term bag will be understood to include all flexible receptacles which are presented in a flat folded stack regardless of whether or not the side edges of those receptacles may be formed with an expansible gusset and re- 16 Claims "ice gardless of the configuration of the bottom of the receptacle so long as it is a receptacle which can be manipulated in the machine. In general terms, the machine comprises a magazine means for a quantity or stack of empty paper or plastic bags positioned with the open ends thereof upwardly, a means for picking off a bag from the stack and transporting it to the point of filling, a means for opening the bag for the reception of the intended contents, a means for closing and sealing the bag after reception of the contents, and a means for discharging the filled and closed bag preparatory to initiating another cycle of operation. As will be later described, the cycle may be automatically repetitive or each cycle may be initiated by some triggering action deriving, for example, from the discharge of a filled and closed bag.

For convenience, the specification will deal with the various sets of mechanism separately, viz., the general frame structure and arrangement of components, the bag magazine means, the control devices, the bag transport means, the bag opening and closing means, and the bag sealing and releasing means, followed by a recitation of a typical cycle of operation of the machine.

Frame structure The frame structure of the machine comprises a top plate 1 supported on a rectangular frame structure formed of angle iron and comprising

side members

2, 2 and

end members

3, 3 supported on angle iron legs 4. Adjacent their lower ends, the legs 4 support a pair of horizontal

angle iron members

5, 5 supporting a plate 6 on which the control devices, hereinafter to be described, are mounted. On the upper surface of the top plate 1, the bag supply or magazine means generally indicated at 7 is mounted adjacent the end thereof that will hereinafter be referred to as the rear end of the machine and extending from the front end of the magazine means to the front end of the machine, the top plate 1 is provided with a clearance opening 8 for movement of certain portions of the mechanism also to be later described. Adjacent its front end, and disposed on either side of the opening 8, the top plate supports the bag opening, closing and sealing means collectively designated as 9, said means being disposed at the point at which the contents are to be deposited in the opened bag.

The under side of the plate 1 carries the operating means for the bag transport apparatus also to be described in detail, the portion thereof which extends above the plate 1 being designated generally by the numeral 10. Preferably, the sides of the frame structure are covered by removable sheet metal plates including

side plates

11, 11 and

end plates

12, 12.

The bar, magazine means The bag supply component 7 includes a pair of

subbase plates

13 and 14, each of said base plates being secured to the plate 1 by a series of four bolts 15 extending one each through a series of four risers 16 and affording operating clearance for supporting and guiding the means employed for maintaining pressure against the stack of bags supported on the bag stack supporting means carried by the

plates

13 and 14. The

plates

13 and 14 are spaced apart a slight distance from each other to form a guiding slot 17 which acts as a guiding channel for the bag stack compressing means. Adjacent the front and rear ends thereof, the

plates

13 and 14 are provided with a pair of parallel

transverse slots

18, 18 in which vertical members 19 are secured by bolts 20 extending through the horizontal foot portions 21 thereof.

The vertical portions of the members 19 are each provided with a pair of elongated slots extending therethrough transversely of the length of the machine and comprising a lower slot 22 and an upper slot 23. The

lower slots adjustably support a bag bottom supporting rail 24 extending parallel to the length of the machine and secured therein by bolts 25. The slots 23 similarly support a corresponding bag guiding rail 26 adjustably secured therein by bolts 27. By lateral adjustment of the members 19 in the slots 18, the bag supporting means can be adjusted to the width of bag being used and by adjustment of the top and bottom bag guiding rails 24 and 26, the height of the bag can be accommodated. The bag bottom supporting rails 24, 24 carry bag bottom supporting ledge means 28, 28 comprising sheet metal plates secured to the under side of said rails by screws 29. Since these bottom rails thus support the lower ends of the stack of bags above the foot portion 21, these foot portions and the uprights can either be disposed with the ends thereof pointing outwardly toward the sides of the top 1 as shown in FIG. 1 or can be reversed to point inwardly to increase the range of width of bags which may be accommodated.

Guided in the slot 17 between the

plates

13 and 14 is the lower end of the bracket member 30 which supports the bag stack compressor plate 31 said lower end of said bracket carrying two pairs of upper rollers 32 engaging the top surfaces of the

plates

13 and 14 and a single pair of cooperating rollers 33 which engages the under surfaces of the plates. The bag stack compressor means including the bracket 30 and plate 31 is constantly yieldingly urged forward by a spring means including a capstan reel 34 on which a cable 35 is wound, said reel being mounted for rotation on the under side of one of the

plates

13 and 14 and said cable being trained around a grooved sheave 36 also mounted on the under side of the same plate and being disposed so that the reach of the cable extending from said reel and around said sheave is caused to extend parallel to and in the center plane of the slot 17 and has the end thereof secured to the lower end face of the bracket member 30 by any suitable means such as a screw 37. This cable and the reel 34 form a part of a commercially available unit mounted on a subbase 38 attached to the under side of the same plate as is the sheave 36. This unit also includes a clock spring means 39 having one end of the clock spring 39' thereof attached to the reel 34 and biased to rotate the reel in a direction to wind up the cable 35. Thus when a stack of bags B is mounted in front of the plate 31, the plate under the bias of the clock spring means 39 exerted through the cable 35 will tend to move the bags toward the front of the holding means to the extend permitted by inwardly extending stop means 40 on the front ends of the upper and lower bag guiding rails 26 and 24 and thus as the foremost bag is picked off the stack by the means presently to be described, the bags are kept pressed forwardly into a predetermined position for engagement by the bag transport means.

The control devices The control devices are mounted on the lower plate 6 and comprise a cycle control means comprising a motor driven switch unit 41 including a driving motor 42 operating a shaft 43 carrying a series of cams 44 and said cams operating a series of electrical switches designated in FIG. 16 as S1-S6. The switches control various portions of the machine as will be described in connection with the individual operating elements controlled thereby. The plate also supports a vacuum pump unit 45 including an electric motor and a vacuum pump connected by conduit means 47 to one side of solenoid operated

valves

48 and 49 which are normally closed and which when energized in a manner presently to be described, are open to allow the vacuum to extend through

lines

50 and 51, respectively, to certain of the bag manipulating means presently to be described. Additionally, the conduit means 47 is connected to a normally open vacuum responsive switch 52 operable through conductors 52' and other means controlled thereby to maintain timed coordination with a bag filling unit and effective to prevent dispensing by the filling means when a bag is not presented and opened for reception of the material being packaged. Additionally, the plate 6 supports a first solenoid actuated compressed air valve 53 connected by

lines

54 and 55 to a double acting cylinder and piston assembly 56 having the piston rod 56' thereof attached to the bag transport means 10, spring means in said valve normally positioning it to maintain the piston rod 56' thereof retracted, and a second solenoid actuated compressed air valve 57 connected by

lines

58 and 59 to a double acting cylinder and piston assembly 60 having the piston rod 60 thereof connected to a bag top clamping means indicated at 61 and spring mean in said valve 57 normally positioning it to cause the piston rod thereof to be retracted as shown in FIGS. 2, 4 and 13. The compressed air supply to these cylinders is received at a conduit means 62 and thence extends through a filtering and pressure reducing unit 63 from which a line 64 extends to the

valves

53 and 57. Additionally, a line 65 extends from the line 64 to a nozzle end 66 disposed in close adjacency to the point at which the bag mouth is positioned for filling and a constant stream of air through this line serves to assist in the opening of the bag by means presently to be described.

The bag transport means The bag transport means 10 includes a supporting head 67 slidably mounted on a first guide rod 68 disposed beneath the plate 1 and extending generally parallel to one side edge of the opening 8 in the plate 1. Adjacent and parallel to the rod 68 is a second guide rod 69 disposed at one side of the head 67 and

rollers

70, 70 engage the upper and lower sides of the rod 69 to prevent rotative movement of the head 67 on the rod 68. At the side thereof opposite the rod 69, the head 67 carries a vertically extending stationary rod 71 which extends above the top surface of the plate 3 and on which the bag engaging head assembly 72 is pivotally mounted by upper and

lower bearings

73, 74. A torsion spring 75 surrounding the rod 71 between the

bearings

73 and 74 has one end thereof attached to the lower bearing 74 and the upper end thereof attached to the rod 71 at 76 and is biased to constantly tend to rotate the bag engaging head assembly counterclockwise as viewed in FIG. 2. The upper end of the rod 71 carries a forwardly extending stop lug 71 positioned to be engaged by a stop member 73 carried by the upper bearing 73, to limit the extent of counterclockwise movement effected by the torsion spring 75. The piston rod 56' of cylinder 56 is attached to the head 67 and when energized by solenoid actuation of the associated valve 53 will be caused to move the bag transport apparatus along the

rods

68 and 69 toward the front of the machine and to move in the opposite direction when the solenoid of the valve 53 is deenergized, the path of travel extending from a point adjacent to the front face of the stack of bags to the point at which a bag is to be opened and filled. The bag engaging assembly includes a head element 78 extending parallel to the face of the bag stack, said element having a longitudinal bore 79 formed therein and at the front face thereof the bore communicates with a passage 80 having a nipple 81 which is connected by the conduit means 50 to valve 48. The rear face of the head 78 is connected by passages 82, 82 with a pair of vacuum cups 83, 83 adapted to secure themselves to the front bag of a stack of bags in the bag supporting means when vacuum is applied thereto,

Mounted on

risers

84, 84 on the top surface of the plate 1 above the

guide rods

68 and 69 is a cam plate 85 having a camming surface comprising a first run 86 extending from a short distance from the rear end of the plate 85 and disposed outwardly from the adjacent edge of the opening 3, a second portion 87 spaced inwardly from the said edge of the opening 3 and an inclined portion 88 connecting these two portions.

In the plane of the cam plate 85, the vertical portion 89 of the bag transport assembly 72 which carries the bearing lugs 73 and 74 and the head 78 carries a laterally extending arm portion 74' carrying a roller 90 which engages the said cam face. As the bag transport head is moved forwardly or from left to right as viewed in FIGS. 1 and 2, the roller 90 engaging the cam face portion 86 will not be aifected and the suction cups and head will be in the position shown in FIG. 5. As continued forward movement of the head occurs, the roller will engage the inclined portion 88 (see FIG. 6) and will tend to swing the entire head about rod 72 in a clockwise direction until the roller contacts the second straight face 87 of the cam plate and (see FIG. 11) in which position the entire head has been turned at right angles. Assuming that the vacuum has been supplied to the

cups

83, 83, at the time when they were in engagement with the bag stack, they will have picked olf the front bag b and have carried it with them as shown particularly in FIGS. 6 and 7, bringing the bag to the point of filling (FIG. 11) and between the opposing jaws of the bag opening, closing and sealing means. When the bag has been filled, closed and sealed, the control mechanism will have returned the head to its initial position and the tension of the spring 75 will cause the head and suction cups to follow the cam and be positioned for picking up the next bag for the next cycle of operation.

The bag opening, closing and sealing means The bag opening, closing and sealing means includes a fixed jaw element mounted on the plate 1 adjacent the forward end of the opening 8 and at the same side thereof as the cam plate 85 and a movable jaw assembly mounted substantially directly oppositely. The fixed jaw assembly comprises a pair of

vertical standards

91, 91 extending upwardly and carrying the fixed jaw component 92 mounted thereon by means of threaded

studs

93, 93 extending through the upper ends of the

members

91, 91 to permit adjustment of the fixed jaw member 92 transversely of the machine by means of

nuts

94, 94 engaging opposite faces of the

members

91, 91.

The movable jaw assembly generally indicated at 95 comprises a pair of

vertical standards

96, 96 fixed to and rising from the forward end of the plate 1 transversely opposite from the fixed jaw assembly at the opposite side of the opening 8. A plate 97 is secured to the upper ends of these members by bolts 98 and mounted on the plate 97 by

brackets

99, 99 is the movable jaw actuating air cylinder 60, the piston rod 60' of which extends out of both ends of the cylinder. The cylinder is disposed at right angles to the length of the machine and the portion of the piston rod 60' which extends from the rear end of the cylinder carries a depending head 100, the lower end of which carries a pair of rollers 101 which engage opposite sides of a guide member 102 attached to the under side of the plate 97. The opposite end of the piston rod 99 carries a head 103 which carries a clamping jaw 104 which is complementary to the fixed jaw 92 and also carries below said jaw a head 105 carrying a pair of vacuum cups 106, 106 which are complementary to the

cups

83, 83, said head 105 having an internal conduit aifording connection of the

cups

106, 106 with the vacuum conduit line 51.

The

jaws

92 and 104 contain resistant heating elements 107 and 108, respectively, for heat sealing the mouth of a bag clamped there-between.

Operation of the machine Assuming that a stack of bags is placed in the magazine and that all adjustments have been made for the particular size of bag and that the machine is positioned in association with a suitable filling instrumentality, upon starting the machine and the beginning of rotation of the motor 42, switch S1 will energize valve 53 to cause air pressure to be admitted to the end of air cylinder 56 causing the bag transport means to move away from the bag stack, and at that time, switch S2 has energized valve 48 to cause vacuum on the

cups

83, 83 to engage a bag and carry it between the then open

jaws

92 and 104, it being noted that the jaws are disposed above the level of the vacuum cups 83, 83 and the head 78 on which they are mounted and in a horizontal plane just below the upper ends of the bags in the stack so that the upper end of the bag will be positioned between the opposing faces of the

jaws

92 and 104. As the bag is thus positioned, the air jet of the nozzle 66 will strike the top of the bag and tend to open it. At the same time, the switch S3 will open the vacuum cups 106, 106 to vacuum through the line 51 and simultaneously, the switch S4 will energize the valve 57 to open for a brief period of time, said time being sufiicient to cause the cylinder 60 to move the jaw 104 and the vacuum cups carried thereby forward to a point at which the cups contact the side of the bag which, if necessary, may have been distended by an air jet from the nozzle 66 (some bags may not require the jet assist) and the vacuum will secure the side of the bag to the cups before the jaw 104 will have contacted the jaw 92. The switch which operates valve 57 is immediately disabled and the spring means of the valve reverses the pressure in the cylinder, causing the movable jaw to retract and carry the side of the bag with it thus holding the bag opened and positioned to be filled with whatever contents are to be placed therein. When the filling is completed (this may be automatic or may be controlled by a signal deriving from the switch 52) the switch S5, which also controls valve 57, is energized to apply pressure to again cause the piston rod 60 to move forward, the cam of switch S5 operating to hold the switch closed a suflicient length of time so that the air supplied to the cylinder will cause the jaw 104 to move into tight engagement with the bag mouth and clamp it against the fixed jaw 92 and, since the said jaws are heated by the heating elements 107 and 108, the bag will be sealed. At the end of an interval suflicient to effect the sealing of the bag, the switch S5 breaks the current and the spring means Within the valve 57 permits the valve to reverse the pressure applied to cylinder 60 with resultant dropping of the filled, closed and sealed bag into the chute 109. As an incident to this gripping and sealing operation, the

vacuum valves

48 and 49 will have been disabled and the bag transport unit has been retracted as an incident to opening of switch S1 with resultant reversal of the application of pressure to the cylinder 56. Since once the bag has been gripped between the

jaws

92 and 104 the presence of the guide transport means at that end of the machine is no longer required.

The vacuum cups 106 project slightly forwardly of the jaw 104 and thus in those instances in which an air jet is not employed will contact the bag in advance of contact by the jaw 104. When the jaw 104 is again advanced for the sealing step, the resilience of these cups accommodates the added forward movement for that purpose. Thus in those instances in which the air jet is not used, the vacuum cups contact the bag to be opened before the sealing jaw 104 effects contact therewith.

The switch S6 and vacuum responsive switch 52 are optionally employed for cyclic control of the filling unit if that is necessary or desirable. If, for example, the supply of bags is exhausted, the opening and closing of switch S6 could cause the filling unit to continue to drop batches of material. Normally open, vacuum responsive switch 52, being connected in series with switch S6 through the filling apparatus, will remain closed whenever an opened bag is held in position by the vacuum cups, thus allowing the filling unit to operate only under those conditions. If the cups are not gripping a bag, there will be no vacuum and the switch 52 will remain open thus preventing discharge of contents in the absence of a properly positioned bag.

The timing as determined by the switch unit 44 can be that which is best suited to a particular use. For example, if the filling portion of the cycle should be slow by reason of the nature of the product, the bag transporting head may be moved back ready to pick up the next bag while the filling of the preceding bag is taking place. As another example, the forward movement of the next bag to be filled may be timed to take place while the sealing of the preceding bag is taking place. These involve only the Shaping and timing of the appropriate cams of the switch unit.

While in the foregoing specification a presently preferred embodiment of the invention has been described, it will be appreciated that such description has been by way of example wherefore, it is not to be deemed that the invention is limited to the precise details of construction and operation thus disclosed and it will be understood that the invention includes as well all such changes and modifications in the parts and the construction, combination and arrangement of parts as shall come within the purview of the appended claims.

I claim:

1. In a machine for opening and closing bags as an incident to the filling of such bags, a frame structure, a magazine means on said frame structure supporting a supply of collapsed bags, a bag transport means movable on said frame structure operable to engage and remove a collapsed bag from said magazine means and transport the bag to a point at which the bag is to be filled, other means on said frame structure disposed adjacent to said point of bag filling operable to open a bag held by said transport means at said point, and a bag sealing means disposed at said point operable to engage and close the filled bag while the bag is being held by said transport means.

2. A bag opening and closing machine as claimed in claim 1 in which the bag engaging instrumentality of said transport means comprises a vacuum operated member engaging a side of the bag to be transported.

3. A bag opening and closing machine as claimed in claim 2 in which said bag opening means includes vacuum operated devices engageable with a side of the bag opposite the side engaged by the vacuum operated member of said transport means.

4. A bag opening and closing machine as claimed in claim 1 in which said bag transport means includes means effective to cause said transport means to effect a turning movement about a vertical axis to position the engaged bag at righ angles to the position occupied in the magazine at the time the engaged bag is positioned for engagement by said bag opening means.

'5. A bag opening and closing machine as claimed in claim 3 in which said sealing means is disposed in a horizontal plane above a plane at which the bag is engaged by the vacuum operated member of said transport means and the vacuum operated devices of said bag opening means.

6. A bag opening and closing machine as claimed in claim 1 in which said bag transport means is operated by a pneumatic cylinder means on said frame structure.

7. A bag opening and closing machine as claimed in claim 3 in which said bag sealing means comprises heat sealing means including a fixed jaw element engagable with one side of the bag and a movable jaw element movable into and out of engagement with the other side of the bag in opposition to said fixed jaw element by a pneumatic cylinder means.

8. A bag opening and closing machine as claimed in claim 1 in which said bag transport means and said bag opening means serve additionally as the supporting means for a bag while it is being filled.

9. A bag opening and closing machine as claimed in claim 1 in which said bag transporting means and said bag opening means each include vacuum operated bag contacting means, in which said machine includes a vacuum pump means connected by conduit means to said vacuum operated means, and in which a normally open, vacuum responsive switch is connected to said conduit,

the electrical contacts of said switch being rendered efiective, in the absence of vacuum in said conduit means, to open an electrical circuit controlling the operation of a bag filling instrumentality associated with said machine with resultant prevention of actuation of the filling instrumentality at any time when malfunction of said machine fails to present an opened bag for reception of contents from the filling instrumentality.

10. A bag opening and closing machine as claimed in claim 1 in which vacuum operated bag engaging devices are carried by said bag transport means and said bag opening means, in which a first reversible pneumatic cylinder and piston means is connected to said bag transport means, in which a second reversible pneumatic cylinder and piston means is operably connected to said bag opening means in which a first series of valves separately connect each of said bag engaging devices with a source of vacuum and a second series of valves separately connect each of said cylinder and piston means with a source of pneumatic pressure, and in which a power operated series of switches separately connected to each of said valves serves to operate said bag engaging devices and said cylinder and piston means in a predetermined timed sequence.

11. A bag opening and closing machine as claimed in claim 2 in which said magazine means includes stop means engaging edge portions of the bag supply at the end of said magazine engaged by said vacuum operated devices of said transport means and in which a yieldingly mounted pressure plate member engages the opposite end of the bag supply.

12. A bag opening and closing machine as claimed in claim 3 in which an air jet means disposed adjacent the point at which a bag is filled initiates the bag opening operation.

13. A bag opening and closing machine as claimed in claim 4 in which said bag transport means includes a head slidably mounted on guide means carried by said frame structure in a path extending between the point of engagement with the bag supply and the point at which the bag is opened, filled and closed, and in which a stationary cam means disposed adjacent to said path is engaged by a cam follower on said head and is operative by such engagement to effect said turning movement.

14. A bag opening and closing machine as claimed in claim 5 in which said magazine means includes vertically adjustable bag supporting rails engaging opposite lower corners of the bag supply the adjustment of said rails serving to position the supply of bags vertically so that the tops thereof are engageable by the bag sealing means.

15. A bag opening and closing machine as claimed in claim 6 in which said pneumatic cylinder is reversible and is connected to a source of compressed air through a reversing valve which is spring biased to normally cause said cylinder to move said bag transport means into engagement with the bag supply.

16. A bag opening and closing machine as claimed in claim 7 in which said vacuum operated devices of said bag opening means are mounted for movement by the one of said pneumatic cylinders which operates said movable jaw element of said bag sealing means.

References Cited UNITED STATES PATENTS 2,725,168 11/1955 Lindstaedt et al. 53-386 X 2,952,954 9/1960 Perrin 53-373 X 2,958,990 11/1960 Kerker S363 X 3,208,194 9/1965 Johnson et a1 53190 TRAVIS S. McGEEHBE, Primary Examiner.

R. L. SPRUILL, Assistant Examiner.

US. Cl. X.R.