Bag opening and spreading mechanism

June 24, 1952

V. G. WILLIAMS

BAG OPENING AND SPREADING MECHANISM

2,601,480

Filed July 13, 1948

Sheets-Sheet 1

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VICTOR. G. WILLIAMS.

June 24, 1952

V. G. WILLIAMS

2,601,480

BAG OPENING AND SPREADING MECHANISM

Filed July 13, 1948

Sheets-Sheet 2

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INVENTOR.

VICTOR. GMLLMMS.

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atty.

June 24, 1952

V. G. WILLIAMS

BAG OPENING AND SPREADING MECHANISM

2,601,480

Filed July 13, 1948

Sheets-Sheet 3

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* I*

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i//://

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INVENTOR.

VICTOR.GWILUAMS.

ATTN.

Patented June 24, 1952

2,601,480

UNITED STATES PATENT OFFICE

2,601,489

BAG OPENING AND5SPREADINGMECHANISM;

Victor-George; Williams, Toronto, Ontario; Can-* ada, .assignor;*by mesne assignments,. toxDelamere &amp; Williams Company, Limited, Toronto, Ontario, Canada

Application July 13, 1948, Serial No. 38,377

Claims.· ( l:i

The. .invention* relates -to. new and useful im- . provements in apparatus.for* automatically pack-. * aging commodities in bags and has particular reference to the means for opening and /spreading? the* bags preparatory to. the. filling or charg- ing thereof.

The bag particularly contemplated by thO invention is a tubular* structure do which, spaced axial creases impart a generally rectangular perimeter. Tiiere are -thereby .*formed therein stwo ] parallel •wide^sidesji hereinafter referred «to as panels;; joined *foy marrowusides-voii gussets. In the conventional flat-folded or. collapsed form in which flt is-delivered by. the bag manufacturer the gussets, are tucked between the panels which : are then.·* turned up and cemented in the usual . manner to form *.a bottom closure, the remaining open end.being.the. mouth of the bag. Upon expansion to full commercial capacity, the closed end of the bag is to be spread .’into a flat bot- . tom .with. * a rectangularoutline corresponding, dimensionally to the measurements* at the bag mouth.

The.actual3spreading'..ofca bag.is normally; pre- ' ceded by the;-step Ofpreliminarilyopening-it to : ί admit the; .spreading 'mechanism; - Past .opening means have proven too forcible for the bags, particularly .at 'higher operational, speeds;*: whereby many bags were torn: and .the entire, process thus * resultantly, .delayed and disturbed.:. Thisisituas: ·; tion necessitated that the machines be run slowly which, understandably, had a markedly adverse effect on the economy of the entire, bagging process.

It is therefore the broad object of thei.4n.ven- ; tion to provide a.safe means, associable with:or forming part of a bagging machine of the character contemplated, for: opening and spreading bags .and 'delivering them to a suitable: conveying mechanism at higher speeds than has heretofore z been customary.

It*.is also;, an important-.o*bject of ..the invention:; to provide new. .and improved means forj.prelimig*· narily. opening the bags under consideration.

It is a further ohject of the invention .to pro- t vide means for flattening; or * squaring the* bottom of a bag of the character described.

It is a still further object of the -invention to . provide means for operating upon the side.gussets of the said bag, particularly but not exclusively £ adjacent the bottom* where thev are caught between the panels, in such wise as to preclude the tendency thereof to return the bag to its original, collapsed condition.

Other objects .of the invention, more or less-.fl

J.226—49)

2*1 .

broad -than those hereinbefore described will ap-. pear* from ·the following.(description; ofethegelem ments, parts and principles constituting the -invention which is.illustrated in the annexed draw;: ings of a preferred embodiment: thereof,: by way of example only, wherein:

Fig. 1 is ' a sideeelevational .view of: the. in vention partly seetionedto expose some of the parts, Figi-S^s-a'yiewisirnilar-to. Fig.. 1 at.a stage in * the operation thereof, *

Fig. 3—a side-elevationalaview partly in section i of ; a detail of: .theaimtentioniata a .further lopers* j ational stage;

Fig.. 4—a (perspectivecyiew .partially-cut; away - * showing .the .side. front and rear of..:a :partiallyi opened bag as contemplated by the invention.

Fig. 5—a view similar;to *Figg*:4 wherein the. bag · is fully expanded,

Fig. 6—a: fronr-elevational viewwfe :a part *»fc i the bag expanding mechanism,·.

Fig.i.74-a perspective view ofctherside:and; front:*; of the invention,.

Figs;..8,&gt;9 and 10—a sectional view of the parts shown in Fig. . 6 at various, stages in thenoper&gt; ation thereof,

Fig.ll—a front elevationalwiew of.the invention, and

Figs.; 12:and:i3=-front:eIevationaL views* of a modification of the:.bottom;forming..mechanism * appearing.inFigSiiS to 10.

Like reference numerals; refer to. likeparts of the invention throughout the.- enumerated -views.

The bagui, contemplated iby .this preferred embodiment of the invention comprises a frontipanel* 2, a somewhat higher back panel 3 terminating,in the conventional flap 4, gussets 5=5 .linkingthe panels 2 and3 and a.bottom’.6, substantially as will appear from. Figs; 4 and 5 .of. the drawings,... It is noteworthy .that in .the construction of the present bag, the gussets 5—5 are-.cemented in folded position to the bottonx.6^fthebag I.

Sincepneithercthe bag filling, nor. the sealing', mechanism- with which the instant invention .is.· intended to be associated,-form part hereof·,· only.', such portions thereof as'Cooperate with .the-present apparatusiwill.be illustrated-in the drawings.and referred to herein. One such part is the conveyor .-8 which is arranged ahead of and;in.•bag receiving relation to the bag opening and spreading means to be described and which is. adapted to convey expanded bags-1 to -the filling ; mechanism (not shown). The-conveyor. *8 .-includes a series of bag receiving sockets 8 overflying a bed 10.

2,601,480

Another such part is the eccentric means for delivering reciprocating power from the driving mechanism of the packaging machine to the instant apparatus, the said eccentric means consisting of a crank member ί I mounted on rotating shaft S and associated with pitman 12. The reference letter “F” is generally applied to the packaging machine frame and/or to various portions thereof.

One of the broad objects of the invention is achieved by restrainably poising a movable panel engaging element above the bag I. Resilient bag-entering tension is constantly maintained thereon which, when the restraint is removed, moves the said element only so far as will enable it to operate on the bag I without damaging it, irrespective of the speed at which the process is performed.

It should be noted that herein, the term “opening” is restricted in application to the bag mouth only while the other more comprehensive terms, “spreading” or “expansion,” refer to the entire bag 1.

The instant apparatus includes a ram 15 which is reciprocable in a channelled ram guide 16 carried by the frame F of the packaging machine. From its upper portion projects a wrist pin 17 to which the pitman 12 is suitably connected. Enclosing the ram 15 in its guide 16 is the cover plate 18 which is secured to the said ram guide 16 either directly or, as may be necessitated by the size of the ram 15, through shims 19, and has a median slot 20 for the wrist pin 17. Beyond the lower end of the ram guide 16, the cover plate 18, still slotted, is inclined away therefrom terminating in a boss 21 housing a through-going, headed, spring controlled bumper 23.

Also suitably secured to the frame P is an open ended magazine 25 for a stack 26 of bags I which is equipped with conventional stack advancing means such as spring 24. A stop 27 is fixed to the frame F at the delivery end of the magazine 25 tapering to a chisel-pointed offset claw 28 which is so positioned relative to the magazine 25 that it is adapted to engage the top flap 4 of the bag I leading the stack 26 thereof. Moreover, its position is also such that it extends to but does not intersect the path of the ram 1.5 for reasons which will duly appear. Air passages 29 therein from an air hose connecting nipple 36 are adapted to conduct and discharge air, whether continuously or intermittently, through the offset claw 28 of the stop 27. When so discharged, the air tends to puff open the mouth of the leading bag I. It should be observed that the pressure of the spring 24 on the stack 26 is communicated therethrough and causes, in effect, the flap 4 to be grasped by stop 27.

The means for completing the preliminary opening of the bag I includes a hair-pin shackle 34 saddled over the wrist pin 17 between pitman 12 and ram guide cover plate 18 and terminating in bushings 35—35 accommodating trunnions 36—36 trammeled in slots 37—37 formed in walls

38— 38 projecting from juxtaposed angle brackets

39— 39 secured to the said cover plate 18. The said trunnions 36—36 extend from one end of a finger 40 which, passing through and playing in the cover plate slot 20, is adapted to reach to and contact the offset claw 28 of the stop 27, being poised for entry into the leading bag i. By referring particularly to Figs. 1, 2 and 3 of the drawings, it will be seen that when so disposed the intermediate portion of the said finger 40 thus intersects the path of the ram 15.

A tension spring 41 anchored to the boss 21 is connected to the finger 40 in such wise as to urge the free end thereof against the stop 27, which said free end is somewhat offset and chisel pointed and is hereinafter referred to as its claw 44. It is noteworthy that the said tension spring 41 also applies a downward pull to the finger 40 urging its entry into the bag I but that such movement is restrained or counteracted by the shackle 34 when it is raised by ram 15 through the intermedium of wrist pin 17.

Thus as ram 15 and wrist pin 17 begin their descent, and thereby remove the restraint on the wrist pin saddling shackle 34, the tension spring 41 is permitted to pull the finger trunnions 36—36 down in the angle bracket slots 37—37 whereby the co-moving finger claw 44 slides down the stop 27 into the bag I in front panel 2 engaging position; the said slots 37—37 limiting the depth of penetration thereinto and hence precluding injury to the bag I irrespective of the speed at which the entry is effected.

Continuing its movement to its next ensuing position with the wrist pin 17 travelling inside shackle 34, the ram 15 then intervenes between the stop 27 and the finger 40, diverting the latter with the front panel 2 towards the bumper 23 between which two elements the said front panel 2 is grasped.

The mouth of the bag 1 being thus fully opened, the ram (5 assumes its next position in the bag

I. It should have been stated that the crosssectional measurements of the ram 15, as contemplated by the present embodiment of the invention, are slightly less than the corresponding interior measurements of the bag I when it is fully expanded. Thus on entering therein the ram 15 tends to spread the bag I to nearmaximum capacity. On contacting its bottom 6 the ram 15 then disengages the bag 1 from the respective grasps of the stop 27 on the one hand and from the finger 40 and bumper 23 on the other hand and carries it towards the conveyor 8 lying therebelow in one of whose sockets 9 it is then deposited. This being the bottom of its stroke, the ram 15 then rises, passing the finger 40 which is then restored by tension spring 41 to pre-intervention position, and re-engages shackle 34 raising it and finger 40 to the positions initially occupied thereby at the commencement of the downward stroke. This completes one up-and-down cycle of the ram 15.

As has been already said, one of the objects of the invention is to impart a flat rectangular character to the bag bottom 6 as shown particularly in Fig. 5 and identified by reference 6'. Prior to this step the bag 1 is substantially wedgeshaped (Fig. 4) with the folded gussets 5—5 caught at the bottom 6 of the bag I. Thus, to facilitate its entry thereinto, the terminus or head 45 of the ram 15 is tapered as illustrated and is hollowed, moreover, to accommodate the bottom forming mechanism to be described.

The said mechanism includes a recessibly projecting plunger 46 having a shaft 47 and a tongue 48, the upper portions of whose sides incline towards and merge with the shaft 47, the said inclined portions being hereinafter termed the slopes 49—49. The plunger 46 is movable axially of the ram 15, its shaft 47 being fitted with a compression spring 50 and slidably engaged in a bearing 51 suitably disposed in and forming an integral part of the head 45. Fastening means, such as nut 47', serves to retain the shaft 47 in the bearing 51 which latter element also forms

2,βο: 5 one abutment for the compression spring 50, the other being shoulder 50' on.shaft 47.

Flanking the plunger 46 are-a'Pair of‘substantially triangular spreaders 52—52 each whereof is expellably suspended by its apex inside the head * 45, being adapted to be expelled therefrom through - a slot 53. in the side of the said head 45/ One side or facet 54 of each spreader 52 is adapted to abut a plunger slope 49 through whose interaction the said spreader- 52 is pressed outwardly i or expelled from the head 45 as the plunger 46 is pushed back thereinto. One or more pull springs 55‘ interconnect the spreaders 52—52, through - suitable media, whereby they are retractable back-into -the said head 45- as the i counter pressure thereon is abated.

It. will now be apparent that when the ram 15 enters the bag I and carries it to the socket 9 on the conveyor S in the manner hereinbefore described, the plunger tongue 43 will strike the 2 socket bed 19 and be thus recessed into the ram head 45 expelling the spreaders 52—52 and forcing them against the bag gussets 5—5. These latter members being cemented in tucked-in position as aforesaid, the effect of the spreaders 52— 2 52 thereon is to form a new transverse crease 5' in each thereof adjacent the new bottom 6' thus causing or at least assisting the gussets 5—5 to assume a desirable perpendicularity.

The thickness of the head 45 being substantially 3 equal to the corresponding dimension of the bag i, it is adapted to crease the panels 2 and 3 accordingly, which effect combines with the new gusset creases 5'—5' to completely reshape or square the bag bottom 6 of Fig. 4 to the form de- 3 noted by reference 6' in Fig. 5.

According to the nature of the bag material, the effect of the new gusset creases 5'—5' may be found inadequate to completely perpendicularize the gussets 5—5 whereby to maintain the 4 mouth of the bag I as fully open as is necessary, for filling purposes for example. To obviate this contingency it has proven efficacious to form a second transverse crease or dent 69 slightly below the top edge of each gusset 5. 4

For this purpose there is provided a rib 61 at suitable bag-entering level on each side 15' of the ram 15, and a ram contacting roller 62 formed of, or at least rimmed with, rubber or other comparable resilient substance, mounted on the 5 frame F.

Thus while the ram 15 is carrying the bag I to the conveyor 8, the rib 61 will pass the roller 62, pressing thereinto through the bag material to form the dent 60. 5

It will be seen that each roller 62 has the additional advantageous faculty of ironing out its associated gusset 5 against the ram 15 whereby to further stiffen it.

It need hardly be pointed out that when the 6 ram IS is raised to complete the cycle, the compression spring 51 will again eject the plunger tongue 43 thus enabling the pull spring 55 to retract the spreaders 52—52 to pre-expulsion position. 6

In Figs. 12 and 13 of the drawings appears a modification of the bottom forming mechanism hereinbefore described and illustrated in Figs. 8, 9 and 10; the principal object of the modification being to do away with pull springs 55. 7

Each new spreader 7 0 is more or less bell-crankshaped terminating at its top in a tail piece 71, besides having other properties, such as facet 72, in common with its prototype spreader 52. The new plunger 73 also corresponds to its counter- ⁷ l,4S0 part plunger 43 in that it has a tongue 74 and slopes 75—75 adapted to co-operate with facets 72—72 of the new spreaders 76—70. Herein, however, the plunger head 75 has another pair of&gt; slopes or cam surfaces 77—77 whereof each is adapted to act on a tail piece 71.

The arrangement of the parts is such that the inward movement of the plunger 73 expels each spreader 79 through the¹ interaction of facet72 · 0 and slope :7-51- Subsequently, when the plunger:73 is again projected through the rani head 45, each cam: surface -71 acts on a tail piece 71 to· restore thespreader'79‘to ‘pre-ex-pulsidii‘position;

Herein, also, the tongue 74 has a slot 80 in 5 which fits-fixbd‘guide pin 81; the‘object whereof is to maintain the co-axial relationship ‘of the plunger‘73‘andthe‘ram 15.

The instant embodiment of the invention has been thoroughly tested, and found eminently 0 satisfactory, and has hence been selected for illustrative ‘purposes; However, it is -well understood that many structural changes can be madeun the apparatus herein described which may make for equal or lesser efficiency. These, together with 5 certain structural details which are common to the art, having been omitted herefrom for the sake of simplicity and clarity, it is not to be construed that such omission constitutes an abandonment of any of the forms of the inven0 t-ion which falls within the purview of the following claims.