US3197936A

US3197936A - Method and apparatus for conditioning bags for loading

Info

Publication number: US3197936A
Application number: US143392A
Authority: US
Inventors: Edwin E Messmer
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-10-06
Filing date: 1961-10-06
Publication date: 1965-08-03
Anticipated expiration: 1982-08-03

Description

Aug. 3, 1965 E. E. MESSMER METHOD AND APPARATUS FOR CONDITIONING BAGS FOR LOADING 4 Sheets-Sheet 1 Filed Oct. 6. 1961 INVENTOR. foul/v E. Mess/46g Aug. 3, 1965 E. E. MESSMER 3,197,936

METHOD AND APPARATUS FOR CONDITIONING BAGS FOR LOADING Filed 001;. 6. 1961 g- 1965 E. E. MESSMER 3,197,936

METHOD AND APPARATUS FOR CONDITIONING BAGS FOR LOADING Filed Oct. 6. 1961 4 Sheets-Sheet 5 1 :F I- g W of: S T: N 7:: I I ll q q INVENTOR: 8 Emmy 5 Mess/-10 Aug. 3, 1965 E. E. MESSMER METHOD AND APPARATUS FOR CONDITIONING BAGS FOR LOADING 4 Sheets-Sheet 4 Filed Oct. 6. 1961 United States Patent This invention relates generally to the filling of bags, especially plastic bags, and has particular reference to a method and apparatus for conditioning bags for loading.

In its broadest sense, the term conditioning may in-' clude within its scope the initial formation of the bags from continuous sheet stock which, if desired, may have been previously imprinted with selected descriptive or advertising matter, and electric-eye markings.

The type of bag with which the invention is primarily concerned is the well-known rectangular polyethylene bag whose filling opening or mouth is along one edge. The loading operation for which the bag is to be conditioned is one in which a single article is to be inserted into the bag. Single article is intended to refer to any product which can be readily picked up or handled or pushed as a unitary thing, (such as a shirt or a bundle of paper towels or a stack of bakery or other products or the like), and the loading contemplated by this invention involves the insertion or pushing of such an article, in a substantially horizontal direction, into a bag whose month has been opened to receive it. This loading step may be performed by hand or otherwise. The word article is intended to distinguish the operation of this invention from those in which pourable granular material or other Substances are inserted into bags by downward flow from a hopper or the like. i a

In accordance with present commercial practice, bags of the character referred to are usually manufactured in establishments separate and remote from those at which the bags are to be employed for enclosing articles of merchandise. This requires considerable handling of the bags, e.g., for purposes of storage and shipment, and the limp slippery nature of bags made of polyethylene or the like creates numerous problems. Thus, the bags are difiicult to stack and they constantly slip out of alignment. The ditlicult is aggravated by the fact that for the sake of speed and efficiency loading operations should be performed with bags that are reliably oriented and whose filling openings are readily openable.

It is a general object of this invention to obviate these problems. This object is achieved, in part, by a novel sequence of operations which include handling, arranging, moving and otherwise treating the bags in a special manner just prior to the loading operation, whereby each bag is conditioned readily to receive the article it is intended to enclose. The procedure lends itself to a complete avoidance of all bag-handling operations remote from the point of loading, and preferably includes the formation, at the loading location, of the bag itself.

Another object of the invention is to provide a relatively simple, economical, reliable, and thoroughly practical apparatus by means of which the bags are com ditioned in the contemplated manner and for the purpose described. a t

The preferred bag is one in which the mouth has a protruding lip, i.e., one bag wall is longer thanthe other at the filling openings. This facilitates the opening of the mouth when the bag is to be loaded. The improved procedure of this invention, briefly stated, provides for arranging a succession of such bagsin a row with the bags all in a single substantially horizontal plane and the protruding lips all projecting in the same direction; for an advancement of the bags, in succession, to a loading station; and for then holding the bag lipagainst move- 3,197,935 Patented Aug. 3, 1965 ment while blowing air into the bag to open its month. As an initial step, the bags are preferably formed of continuous sheet stock, one after another, and oriented in a row which projects all lips laterally with respect to the row, the bags being then advanced to the loading station by engagement of the projecting lips.

Among the advantages attained by this procedure is the accurate presentation of each bag to the same predetermined loading position, with the bag mouth reliably opened and ready to receive the article.

The more particular features of the invention include a novel means for delivering newly-formed bags, in succession, to vertically moving conveyor elements which draw the bags away from the forming station and deliver them in oriented fashion to a gripping conveyor traveling in a substantially horizontal direction. It is an important feature of the invention also to provide a novel set of conveyor belts for gripping the protruding lips of the bags and advancing them by means of these lips to an accurate receiving position alongside a loading platform. Other features include a simple but effective mechanism at the loading station for clamping the bag lip of the bag to be loaded and blowing air past the lip into the mouth of the bag; special electric circuitry for operating the gripping conveyor in proper intermittent fashion and reliably halting each bag for a period long enough to allow completion of the loading operation; and novel means for attaining these results automatically in response to the loading process. Moreover, these and other features of the invention, hereinafter to be described in greater detail, are embodied in apparatus which is low in manufacturing cost, unusually inexpensive to operate, and rugged in structure and reliable in operation.

On Way of attaining these objects and advantages, and thus avoiding the many shortcomings of handling procedures heretobefore used, is illustrated in the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view of the method of conditioning bags for loading, in accordance with this invention;

FIGURE 2 is a simplified vertical cross-section of the preferred form of apparatus embodying the features of the invention; 1

FIGURE 2a is an enlarged cross-sectional view along the line 2a-2a of FIGURE 2;

FIGURE 3 is a perspective view of the loading platform and its relation to a bag in readiness for loading;

FIGURE 4is a cross-sectional view substantially along the line 44 of FIGURE 3, showing the parts just prior to the loading operation;

FIGURE 5 is a view similar to FIGURE 4, showing the relationship of the parts during the loading procedure;

FIGURE 6 is an enlargement of a part of FIGURE 5;

FIGURE 7 is a fragmentary perspective view of the parts adjacent to the loading platform as a bag is approaching loading position;

FIGURE 8 is a fragmentary perspective view of the preferred manner of mounting the belts defining the grip ping conveyor;

FIGURE 9 is a fragmentary perspective view of the blower and duct;

FIGURE 10 is a detail cross-section along the line 10- 10 of FIGURE 4; and V FIGURE 11 is a wiring diagram. 1

, Each of the bags shown in FIGURE 1 has bottom and top walls joined along three

edges

26, 21 and 22, leaving the filling opening or mouth 23 along the fourth edge. The bottom wall is somewhat longer than the top wall, thus forming a protruding lip 24. The bags are arranged in a single row, with the lips 24 projecting in the same direction, and they are advanced intermittently in the direction of the arrow 25 to a position directly alongside a loading platform 26. At this position, the protruding lip 24 is held against movement, and air is introduced into the bag mouth as indicated by the arrow 27.. This opens the bag mouth and conditions the bag for receiving an article which is advanced along the loading platform 26 toward and into the bag. The filled bagis then pushed or taken away from the loading position, and the next bag moves up to take its place.

In the preferred procedure, as shown in full lines in FIGURE 1, the projecting lips 24 extend laterally with respect to the direction orlmovement of the row of bags. Under certain circumstances the bags might be oriented as indicated by dot-and-dash lines, and advanced intermittently in the direction of the arrow 28. p In FIGURE 2 I have diagrammatically represented the preferred arrangement of parts in an apparatus embodying the features of the invention and adapted to manufacture the bags themselves just prior to the loading opera tion. A supply roll 29 of continuous plastic sheet stock 30 is mounted on a spindle a ds 31. The material 3%? preferably consists of J-stock, which means that a web of plastic material has been previously doubled upon itself along a medial longitudinal line 33 (see FIGURE 2a), the fold line being slightly off-center so that one longitudinal edge 32 of the original sheet projects slightly beyond the doubled-overopposite logitudinal edge 32. As indicated in FIGURE 1, these longitudinal edges 32' will ultimately provide the endedges of each bag, the medial fold line 33 defining the opposite or rear end of the bag. Thus, to form a succession of bags from J-stock of this kind, it is merely necessary to effect heat-sealing along successively spaced transverse lines which will ultimately define the side edges 2t) and 22 of the bag.

The heat-sealing operation is performed upon the continuous sheet stock by mechanism more fully described and illustrated in my co-pending patent application, now U.S. Patent No. 3,153,608, issued October 20, 1964, comprising a clamp and heater supported for swinging movement on a shaft34, and a backing roller 35. The ad vancement of the sheet stock is intermittent, and each time it is halted in tangential relation to the backing roller 35 the heat-sealing element swings into operation against the plastic material and produces a transverse weld or seal along the line which defines the retreating edge of the completed bag and the advancing edge of the next bag to be formed.

The halting of the sheet stock in proper position is preferably accomplished by an electric-eye mechanism 36 which responds to markings previously imprinted upon the stock 39. Circuitry (not shown) responsive to the operation of the electric-eye causes the advancement of the continuous web 36, over the rollers 37, and downwardly between the rollers 38, to be intermittent. This circuitry also includes a means responsive to a completion .of the heat-sealing operation to resume'the advancement of the sheet.

Since superposed plies of plastic sheeting, such as polyethylene, have a tendency to stick together, especially if they have been rolled up (as at 29), and since any such adhesions make it more. difficult to open the mouths of the bags, the web 30 is caused to pass over a fixed blade 90 just prior to the movement of the web toward the first pair of rollers. 38. The blade 9d is interposed between the plies of the J and the passage of the web over theblade. 90. allows the latter-to-split' the plies apart wherever they may have adhered, and thus assures a uniform and reliable mouth opening procedure at the loading station.

The roller pairs 39-42 constitute conveyor elements which draw the bags, as they are formed, downwardly .tween the strands 51.

away from the forming apparatus 34, 35'. To provide for slippage, each of these roller pairs consists of a pair of parallel shafts each of which carries a set of spaced circular flanges, the flanges on one shaft being out of alignment with those on the other.-

The conveyor elements 39-42. carry the bags down wardly into the range of action of a pair of

belts

43 and 44, on constituting a loop extending around guide pulleys 45, the other constituting a similar loop around guide pulleys 46, these guide pulleys being so located that the direction of travel of the successive bags is changed from a downward direction to a substantialy horizontal direction.

The belts 4-3, 44 deliver the successive bags to a table on which they rest on the upper lap of a belt 47. t is while each bag is on this belt that it reaches the loading position presently to be described.

For the sake of convenience, the term belt has been used in connection with each of the

elements

43, 44, and 47. Actually each of these elements is a plurality of spaced parallel bands or belts, each supported on its own set of pulleys. I

In the representation of bags and plastic material depicted in FIGURE 2, the elements are in a state of movement; The first bag 48 has not yet reached the receiving position adjacent to the loading station. The second bag 49 has its leading edge already engaged by the

belts

43 and 44, while its trailing edge is still interposed between the roller pairs 41, 42. It is because the belts 43 44- advance the bags more rapidly than the conveyor elements 394-2 that slippage of the bag is provided for as previously mentioned. That portion of the strip 36 which has moved past the point of tangency with the backing roller 35 has also not quite completed its movement. It is this leading part 50 which will be cut off from the main length, to form the next succeeding bag, as soon as the advancement of the strip 30 stops temporarily to allow the "

elements

34, 35 to function.

' It will be noted that the extent of travel of the

belts

43, 44 is such that the bag in theregion d8 lies uncovered, so that the upper wall ofthe body of the bag is free to expand upwardly when the bag reaches the loading position. Howver, the bag is not entirely disengaged, and it is a feature of the invention to provide a special conveyor at this stage of bag movement which grips the projecting lip 24. This grippingconveyor is not shown in FIGURE 2, and its arrangement and mode of operation is best illustrated in FIGURES 7 and 8.

As shown in these figures, the gripping conveyor consists of a pair of cooperating lower and upper belt loops adapted to engage the bag lip 24 between them as it emerges from the range of action of the

belts

43, 44. The lower loopsmay consist of two strands, 51, but this is not essential. Where two such strands are used, the upper loop consists of a single strand 52 which straddles the strands 51, thus engaging the lip24 rather firmly as it presses the lip downwardly into the groove be- Theconveyor element constituted of the strands 51 extends around guide pulleys 53 located slightly below .the level of the table 47, so that the upper forwardlyvmovinglap of the conveyor engages the advancing lip 24 from underneath. The upper conveyor loop 52 is guided around a special pulley 54 mounted on a vertical axis in such a position that it directs the forwardlymoving'lap of the belt into substantial alignment with pulley 54. I

At least one of each set of pulleysis driven by an appropriate motor, diagrammatically represented at 56 in thecircuit diagram of FIGURE 11. Through suitable gearing, not shown, thismotor may serve also to drive the belt 47, the pair of

belts

43, 44, and the conveying elements 33-42. The intermittent advance of the plastic stock 3th is brought about by other means, preferably but not necessarily in timed relation to the advancement of the bags from the forming station to the loading station.

As best shown in FIGURE 7, the halting of the bag when it reaches the proper loading position is brought about by a switch 57 (see also FIGURE 11) in the circuit 58 of the motor 56. The switch 57 has a spring-biased arm 59 positioned to be encountered by the leading edge of the advancing bag. When this edge encounters the arm 59 it moves it to the dotted position shown in FIGURE 7, and this serves to open the switch and thus disconnect the motor circuit and bring the motor to a halt. In the accurately located position in which the bag then finds itself, it is ready to be treated and loaded by the special mechanism now to be described.

Hinged to the fixed framework 66' of the machine along a pivot axis 61 is a loading platform 62. It is normally held in the elevated position shown in FIGURE 4 by a weight 63 mounted .at the end of an arm 64 pivoted to the framework at 65 and provided at one end with an upright link 66 secured to the underside of the platform 62. By comparing FIGURES 4 andS, it will be noted that the loading platform 62 is depressible into the position shown in FIGURE 5, against the gravity action of the weight 63. It is the placing of an article to be loaded (indicated at 67 in FIGURES 3 and S) on to the platform 62, and advancing it toward the bag into which it is to be loaded, that causes the downward movement of the platform 62.

The downward movement of the loading platform 62 causes two things to happen automatically. It causes the lip of the bag to be engaged inwardly of the gripping conveyor (see FIGURE 6) by a pair of clamping jaws; and it activates a normally-inoperative blower-and-duct arrangement designed to blow air into the mouth of the bag, as indicated by the arrows in FIGURE 6, to open the bag into a position receptive to the advancing article 67.

The clamping jaws illustrated consist of an upper fixed clamping jaw 68 formed as a forwardly projecting part of an air duct 69 (see FIGURE 9); and a lower complementary clamping jaw 76 formed as part of a bag-supporting table 71 lying directly beneath the upper lap of conveyor 47. This table is pivoted at 72 to the fixed framework 66 of the apparatus, so that the table is elevatable from the normal substantially horizontal position shown in FIGURE 4 to the slightly inclined position shown in FIGURE 5. The upper lap of conveyor 47 yields enough to allow this movement to occur. The elevation of table 71 is brought about by upright link '73 extending between the lever 64 and the underside of table 71.

When each bag approaches the loading position (FIG- URE 7) its protruding lip 24 is guided beneath the fixed jaw 68. Then, when the bag is in proper receiving position the depression of the loading platform 62 to the ,positionof FIGURE Scauses the jaw 70 to rise and clamp the gripper lower bag lip 24 against the jaw 68. This clamping engagement occurs inwardly with respect to the margin of the bag lip which is gripped by the

belts

51, 52.

The duct 69 (FIGURE 9) is a tray-like element positioned directly beneath the loading platform 62 and consisting of two parts. The forward part is fixedly mounted,

being supported, for example, by part 74- of the fixed framework. The rear end 75 is pivoted at 76 to the rear of the fixed part and is deflectable or shiftable between the inoperative position shown in FIGURES 4-and 9,and the lowered operative position shown in FIGURE 5. .The

shiftable duct end .75 tends by its weight to assume. the downward position, but it is held up by a cross-bar 77 6 to assume the inclined position of FIGURE 5. This downward deflection is limited by a fixed part 78 of the framework.

Adjacent to the rear end of the duct is a blower 79 which may be continuously functioning, if desired. Under normal circumstances, the blower and duct are ineffective and air flows uselessly from the discharge nozzle 80 into the lower region of the apparatus. However, whenever the loading platform 62 is depressed the rear duct part 75 positions itself into the air-receiving position (FIGURE 5) whereby the duct becomes eifective to guide the blast to and over the fixed clamping jaw 68 at the outlet end of the duct, thereby leading it directly into the bag month. More particularly, the upper wall of the bag at the loading station, normally in the full-line position shown in FIGURE 6, is blown upwardly to the dot-and-dash position shown in that figure. This action is enhanced by the downwardly angled nature of the clamping jaw '70 and the upwardly angled disposition of the table 71 when it is raised, whereby the bag lip is canted down out of the plane of the bag body, to facilitate the entry of the air into the bag mouth.

Obviously, the opening of the bag mouth conditions the bag for the introduction into it of the article 67. However, it also reduces the pressure of the bag upon the switch element 59, and for this reason the circuit 58 (FIGURE 11) is provided with a second switch 81 in series with switch 57 and automatically opened when the loading platform 62 is depressed. This switch 81 is shown in FIGURE 4 with an upwardly projecting button directly in the path of the platform 62. The button is spring-biased to the switch-closing position shown in FIG- URE 4. When the platform 62 presses down on this button (FIGURE 5) the switch is momentarily opened. Thus, even if the switch 57 recloses, the

conveyors

47, 51, 52 cannot resume movement as long as there is downward pressure on the platform 62. r

The loading platform 62 is preferably associated with a pair of movable opposed lateral guide elements 82. They are mounted on vertical pivots 83 and move between the full-line and dotted-line positions depicted in FIG- URE 3. A spring (FIGURE 10) extends between pins 86 carried by the pivot posts 83, urging the pivots to a normal relationship in which stop pins 84 abut against fixed stops 87. In this normal disposition of the parts the guides 82 converge toward each other at their outlet ends, but the guides are in a retracted location with respect to the bag month. After a bag at the loading position has been blown open, the advancement of the article 67 along the loading platform 62 pushes the guides 82 apart and also forwardly, whereby the converged ends enter the bag mouth momentarily and thus facilitate the insertion of the article. The opening and forward movements of guides 82 is made possible by connecting them .to their pivot posts 33 through radial arms best seen in FIGURE 3. The spring 85 stretches during this action but the spreading of the guides 32 is limited by abutment of pins 86 against stops 8? (FIGURE 10).

Sometimes it is necessary or desirable to impart a final push to the article even after it has moved off the loading platform 62. To hold the bag at the loading station for this additional moment of time, a third switch 92 is inserted in the circuit 58. This switch has a movable part 93 in the path of one of the pins 86 (see FIGURE 10), and whenever the guides 32 are moved apart the switch -92 is automatically opened. Thus, even if the

switches

57 and 81 have reclosed, the conveyors cannot resume movement if the guides 82 are still apart. This makes it

certain thatthe conveyors

47, 51, 52 canmove again only when the bag loading operation has been'completed and the loaded bag moved or lifted away from the loading position. i

i From the description given, it will be apparent that the apparatus shown can be tended by a single operator whose primary function is to move articles 67 successively along the loading platform 62 into bags'receptively positioned in articlevreceiving open-mouthed condition. As each bag is filled it is moved away by the operator, whereby the next bag moves up to loading position. During this instant of time the next succeeding article 67 is grasped by the opera-tor and started on its movement along the platform.

It is contemplated that articles 67 may be delivered to the loading station by conveyors or other means, not shown, or by hand; also, that the loaded bags may be removed in similar fashion. Under some circumstances the entire loading operation might be mechanized, and it will be understood that the functioning of the invention is not dependent upon whether the bags are loaded manually or automatically, nor upon the manner in which the loaded bags are carried away.

The invention makes it possible to do away completely with bag-handling in the period between manufacture and filling. This avoids many of the difliculties heretofore engendered by disorientation or slippage of bags prior to their arrival at the point of loading. It also obviates the slow-downs, and the unreliability, that have previously stemmed from the commonly experienced sticking-tgether of the bag walls during the period between bag formation and loading. In this connection, the separating effect of the blade 90 upon the bag walls, almost immediately preceding the opening of the bags for loading, is highly advantageous and is an important novel feature of the invention.

Of course, some phases of the invention are independent of the bag-forming operation and need not necessarily be employed in an apparatus which includes bag-making equipment. In general, it will be understood that many of the details herein described and illustrated are capable of modification without necessarily departing from the spirit and scope of the invention as expressed in the appended claims.

What is claimed is:

1. In an apparatus for conditioning plastic bags for loading, each bag having a mouth with a protruding lower lip, a bag loading platform, a bag gripping conveyor, means for feeding said bags in succession to said gripping conveyor with said protruding lip presented for engagement by said conveyor, means for intermittently actuating said conveyor to advance the bags successively to an article receiving position alongside said loading platform, and means at said platform for blowing air past said gripped lip into the bag mouth to open the latter.

2. The combination of elements defined in claim 1, in which said conveyor actuating means comprises an electric circuit controlling conveyor movement, and a switch in said circuit having a movable switch arm interposed in the path of adavncement of said bags for encounter by each bag as it reaches the loading position, said encounter resulting in halting the conveyor.

3. The combination of elements defined in claim 2, including another switch in said circuit automatically operable during the insertion of an article into said bag for assuring maintenance of said conveyor in halted condition.

4. The combination of elements defined in claim 1, in which said gripping conveyor is arranged for advancement of the bags in a substantially horizontal direction toward said loading platform, and comprises upper and lower belts adapted to grip the bag lip between them, each belt being an endless loop, and both return laps lying below the level of said loading platform.

5. The combination of elements defined in claim l, in which said gripping conveyor comprises upper and lower endless belts adapted to grip the bag lip between them, and pulleys arranged to maintain thereturn lap of the upper belt below the level of said loading platform.

6. In an apparatus for conditioning plastic bags for loading, each bag having a mouth with a protruding lower lip, a bag loading platform, a bag gripping conveyor,

means for feeding said bags in succession to said gripping conveyor with said protruding lip presented for engagement by said conveyor, means for intermittently actuating said conveyor to advance the bags successively to an article receiving position alongside said loading platform, means at said platform for defiecting the body of the bag away from said gripped lip, and means for blowing air past said lip into the bag mouth to open the latter.

'7. The combination of elements defined in claim 6, said deflecting means comprising a movable support for the bag bodies arran ed alongside said loading platform, and means for moving said support.

8. In an apparatus for conditioning plastic bags for loading, each bag having a mouth with a protruding lower lip, a depressible bag loading platform, a bag gripping conveyor comprising upper and lower belts, means for feeding the bags in succession to said conveyor with said protruding lip presented for engagement between said upper and lower belts, means for intermittently actuating said conveyor to advance the bags successively to an article receiving position alongside said loading platform, an eleva-table support for each bag body at said receiving position, and means operable upon depression of said loading platform for'(l) elevating said support to deflect the bag body away from said gripped lip and (2) blowing air past said lip into the bag mouth to open the latter. 1

9. The combination defined in claim 3, said air-blowing means comprising a duct having an outlet end adjacent to and overlying the gripped bag lip, said outlet end including a partdefining a fixed clamping jaw, and said elevatable support having a part defining a complementary clamping jaw, said jaws clamping said bag lip between them when said elevatable support rises.

M. in a bag loading apparatus, a loading platform adapted to receive an article to be introduced into a plastic bag, a conveyor adapted to move a bag to be loaded to a receiving position alongside said platform with the bag mouth facing said platform, and means operable in response to the placement of said article upon said platform for blowing open the mouth of the bag.

11. The combination of elements defined in claim it), said means comprising a normally ineffective blower and duct, and means for making them effective to establish an air flow from said blower to said bag mouth.

12. The combination of elements defined in claim 10, said means comprising a blower, a normally ineffective duct beneath said platform with an outlet end adjacent to the bag at said receiving position, and means for making said duct effective to establish an air flow through said duct from the blower to said outlet end.

13. The combination of elements defined in claim 10, said means comprising a blower beneath 'said platform, a duct beneath said platform with an outlet end adjacent to the bag at said receiving position and with a shiftable normally inoperative rear end, and means for shifting said rear end to establish an air flow through said duct from the blower to said outlet end.

14. In a bag loading apparatus, a depressible loading platform adapted to receive an article to be introduced into a plastic bag, a conveyor adapted to move 'a bag to be loaded to a receiving position alongside said platform with the bag mouth facing said platform, said platform being so supported that it becomes depressed as said article is advanced along it toward said bag, and means operable upon depression of said platform for blowing open the mouth of the bag.

15. In a bag loading apparatus, a depressible loading platform adapted to receive an article to be introduced into a plastic bag, a conveyor adapted to move a bag to be loaded to a receiving position alongside said platform with the bag mouth facing said platform, said platform being so supported that it becomes depressed as said article is advanced along it toward said bag, and means operable upon depression of said platform for clamping the lower lip of the bag mouth and for blowing said mouth open.

16. The combination of elements defined in claim 15, said clamping means comprising a fixed upper jaw beneath which the lower lip of the bag mouth is guided as the bag moves to said receiving position, and a movable lower jaw adapted to move upwardly to clamp against said lip.

17. The combination of elements defined in claim 15, said means comprising a blower, a normally ineffective duct beneath said platform with an outlet end adjacent to the bag at said receiving position, said outlet end including a fixed jaw overlying the lower lip of the bag mouth, a movable jaw adapted to move upwardly against the fixed jaw, and means for simultaneously moving said movable jaw upwards and making said duct efiective to establish an air flow through said duct from the blower to and over said fixed jaw into the mouth of the clamped bag.

18. In a bag loading apparatus, a depressible loading platform adapted to receive an article to be introduced into a plastic bag having a mouth with a protruding lower lip, a conveyor adapted to move a bag to be loaded to a receiving position alongside said platform with the bag mouth facing said platform, a pair of jaws adapted to clamp said protruding lip when the bag is at said receiving position, said platform being so supported that it becomes depressed as said article is advanced along it toward said bag, and means operable upon depression of said platform for making said jaws effective to clamp said protruding lip and for blowing open the mouth of said clamped bag.

19. In a bag loading apparatus, a depressible loading platform adapted to receive an article to be introduced into a plastic bag having a mouth with a protruding lower lip, a conveyor adapted to move a bag to be loaded to a receiving position alongside said platform with the bag mouth facing said platform, an upper fixed jaw and a lower movable jaw adapted to clamp said protruding lip between them when the bag is at said receiving position, a blower, a normally ineffective duct beneath said platform with its outlet end adjacent to the bag month, said fixed jaw being formed on said duct directly beneath said outlet end, said-platform being so supported that it becomes depressed as said article is advanced along it toward said bag, and means operable upon depression of said platform for moving said lower jaw upwards to clamp the lip of the bag and for making said duct effective to transmit air from the blower to and over said upper jaw into the bag to open the bag mouth.

20. In a bag loading apparatus, a loading platform adapted to receive an article to be introduced into a plastic bag having a mouth with a protruding lower lip, a gripping conveyor adapted to engage said lip and thereby carry the bag to be loaded to a receiving position alongside said platform, said conveyor comprising upper and lower belts gripping said lip between them, a pair of jaws adapted to clamp said lip inwardly of the gripped region when the bag is at said receiving position, and means operable upon advancement of said article along said platform toward said bag for (1) operating said jaws to clamp said bag lip and (2) blowing air into the clamped bag to open its mouth.

21. In a bag loading apparatus, a loading platform adapted to receive an article to be introduced into a plastic bag having a mouth with a protruding lower lip, a gripping conveyor adapted to engage said lip and thereby carry the bag to be loaded to a receiving position alongside said platform, said conveyor comprising upper and lower belts gripping said lip between them, a pair of jaws adapted to clamp said lip inwardly of the gripped region when the bag is at said receiving position, and means operable upon advancement of said article along said platform toward said bag for blowing open the mouth of the bag.

22. The combination with the elements defined in claim 21, of a means for feeding bags in succession to said gripping conveyor and engaging only the body portion of each bag behind its protruding lip.

23. In an apparatus of the character described, a means for forming a succession of plastic bags each of which has a mouth with a protruding lip, a first conveyor adapted to receive said bags as they are formed and to move them in succession away from the forming means with the bag mouths projecting laterally with respect to bag movement, said conveyor comprising belts engaging the body portion of each bag behind its protruding lip, a second conveyor adapted to grip the lip of each successive bag as it is released by the first conveyor and to move the bag in a substantially horizontal plane to a loading station, and means at the loading station for blowing open the mouth of the bag.

24. In an apparatus of the character described, a means for forming a succession of plastic bags each of which has a mouth with a protruding lip, a first conveyor comprising vertically moving elements adapted to receive said bags between them as they are formed and to move them downwardly away from the forming means with the bag mouths projecting laterally with respect to bag movement, said elements engaging the body portion of each bag behind its protruding lip, means for guiding the bags to turn them successively into a horizontal direction of movement, a gripping conveyor comprising upper and lower belts traveling substantially horizontal and adapted to grip the lip of each successive bag as it is released by said guiding means and to advance the bag in a substantially horizontal plane to a loading station, and means at said station for blowing open the mouth of the bag.

25. A method of conditioning plastic bags for loading, each bag having a mouth with a protruding lip, comprising: arranging the bags in a row with the bag bodies in a single horizontal plane and the protruding lips projecting in the same direction and having their inner faces upward, gripping said lips and advancing them in the direction of said row in order to present said bags successively to a loading station, and there maintaining said grip to hold the lip against movement and blowing air into the bag mouth to open it upwardly.

26. In an apparatus of the character described, a means for forming a succession of plastic bags from a continuous web of material having two superposed plies, each bag having a month, said means including mechanism for separating said plies in any region where they may have stuck together, conveyor means engaging the bags as they are formed and transporting them in succession to a loading station, and means at the loading station for blowing open the mouth of the bag.

References Cited by the Examiner UNITED STATES PATENTS 1,851,870 3/32 Rose 53-183 X 2,629,214 2/53 McVey 53187 2,643,496 6/53 Cloud 53-183 2,673,016 3/54 Gerbe 53385 X 2,851,838 9/58 McIntyre et al 53-685 X 2,964,892 12/60 Grosjean 53-188 3,023,558 3/62 Mitchell 53-241 FRANK E. BAILEY, Primary Examiner.

ROBERT A. LEIGHEY, TRAVIS S. McGEI-IEE,

Examiners.