US2580665A

US2580665A - Method for forming paper can bodies

Info

Publication number: US2580665A
Authority: US
Publication date: 1952-01-01
Anticipated expiration: 1969-01-01

Description

Jan. 1, 1952 R. M. DUNNING Erm. 2,580,665

METHOD FOR FORMING PAPER CAN BODIES 4 Sheets-Sheet l Filed June 2, 1945 llll Il Il Jan. 1, 1952 R. M. DUNNING ETAL 2,580,665

METHOD FOR FORMING PAPER CAN BODIES Filed June 2, 1945 4 Sheets--SheeI 2 Jan. l, 1952 R. M. DUNNING I-:rAL 2,580,655

METHOD FOR FORMINO PAPER CAN BODIES 4 Sheefs-Sheei 5 Filed June 2, 1945 Jan. 1, 1952 R. M. DUNNING ETAL 2,580,665

METHOD FOR FORMING PAPER CAN BODIES Filed June 2, 1945 4 sheets-sheet 4 Patented Jan. l, 1952 METHOD FOR lrORMTNG PAPER CAN BODIES Robert M. Dunning and Reynolds Guyer, St. Paul, Minn.,. assignors. to Waldorf Paper Products Company, St.Paul, Minn., 'a corporationA of- Minnesota Applicatie; .nine 2, 1945, serial rnrsaazfzoA Our invention relates to an improvement in method and apparatus for forming paper/can bodies wherein it is desired to produce can bodies at low cost and at high speed.

VCans having 'at least the side Walls thereof formed of paper or similar material have been constructed for a considerable number of years. Most of these can bodies are vformed by spirally Wrapping paper to form a tube to which endclosures maybe attached. While suchcan bodies have proven satisfactory insofar as containing packaged products is concerned. their manufacture has certain diiiculties. vIn the first place such tubes normally must be formed in long lengths and then cut into smaller lengths, thereby requiring two separate operations. In the second place, it is usually necessary to either wrap a label on such a can body or else to print the body after formation thereof. Furthermore such can bodies often have spiral grooves extending about the same which detract from their appearance and strength.y v

It is theobj ect of the -present invention to produce can bodies out of fiat sheets of paper stock.

This flat stock may be easily printed before theA bodies are formed, thereby obviating'the require: ment for a separate label. Furthermore, the'can bodies may be stored in flat form until they are desired, and then quickly formed into tubular formation. As a result it is not necessaryto maintain a large inventory of formed paper can bodies `which require costly space to store before use.

A feature of the present vinvention resides in the formation of cylindricalcan bodies by'bending a plurality of at lsheets into tubular formation with one sheet overlying the other. As aresult a cylindrical can body may be formed .of a plurality-of laminationsof paper board 'orthe like. .i l

A further feature of the present invention lies in the provision of a can body. constructed of sheets of paper board bentinto cylindrical form to provide a laminated body, vand'in so` placing the sheets that the butt, edges of :the various laminations are-in angularly spaced relationship.

An additional object of the present invention isfto produce a can bodystructure of a series of overlying sheets coated with a thermo plastic coating. Thus wijlenl the fiat lsheetshave been bent into cylindrical form andy are positioned in' overlyingv relationship, thesesheets may be adhered together by the-` application of heat and These andjother'objects features of? 2 our invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of our specification:

Figure 1 is a perspective View of a can, the body of which has been formed by our method.

Figure 2 is a sectional View through the can body showing the construction thereof.

Figure 3 is a View similar to Figure 2 showing the application of a strip of adhesive tape or the like to assist in holding the sheets in proper relationship.

Figure 4 is a sectional View through a modied form of can body construction.

. Figure 5 is a diagrammatic side elevational view' of our can body forming apparatus showing the construction thereof.

Figure 6 Ais an enlarged detailed view showing diagrammatically the forward end of the body forming apparatus.

Figure 7 is an enlarged view showing diagrammatically the intermediate portion of the can body forming apparatus.

Figure 8 is an elevational view showing in en- 25 larged form the discharge end of the can body forming mechanism.

Figure .9 is a diagrammatic section on the line 9-9 of Figure 6. f

Figure 1'0 is a diagrammatic section on the line Figure 16 is a diagrammatic section on the line l 6-[6 of Figure 8. Y

Figure 17 is a diagrammatic section on the line ll--H of Figure 8. v

Figure 18 is a sectional view through the completed can body.

In lorder thatit bel clearly understood whattype of construction is to be formed by the method and apparatus shown', typical construction is shown in Figures 1 through 4 of the drawings.

Figure 1 shows a ycan'` A' having a side wall B made of paper or similar material which was'bent from .nat form into cylindrical form. The can A is shown having metal ends Il and I2 which arecrimpedl onto the ends of thefside Wall body B in the usual manner. The closure II may include a lling aperture normally closed by a plug cap I3 if it is so desired. Can ends of the type illustrated have been commonly used for a considerable period of years.

In order to show the construction of the side wall body A we have shown this body in section in Figure 2' of the drawings. Figure 2 il.- lustrates an inner sheet I4 which is provided with butting longitudinal edges I5 and I6. This inner sheet I4 is encircled bya second or outer sheet I'I having butting longitudinal edges I9 and 29. The sheets I4 and I'I are secured to gether by any suitable means such as the layer of thermoplastic adhesive 2l between these sheets. Other adhesive could likewise be used but the thermo plastic adhesive isv to be preferred.

In Figure 3 of the drawings 'I'disclose the can wall body B which is identical with that shown in Figure 2 of the drawings, except that a piece of adhesive tape22 is provided over the butting edges I9 and 260i, the outer sheet I1. This tape 22 may be paper tape, bearing, a suitable adhesive, may be transparent tape, or may be pres'- sure sensitive tape if it is desired. Figure 3 merely illustrates the manner in which such a tape may be used if it is desired.

Figure 4 ofV the drawings showsV a modified form` of construction illustrating the manner in which a. wall body having` three plies may be constructed, if desired. In this type of` construction C the inner sheet 23 is folded.

atv

24 and 25 along parallel lines so that the longitudinal edges 26 and. 21, thereof may overlie portions of the intermediate section of the` sheet. In other Words, the sheet is diivded into three panels comprising an intermediate panelY and two end panels foldably connected thereto along parallel fold lines. The end panelsareof.; about one-quarter the area of the intermediate panel so that when thev inner sheetis curved as.V illustrated in Figure 4, the. outer. panels 26 'and. 2l will form a substantially semi-circular double sheet.

The outer sheet 29 of.. the can wall body is a central panel 30 andtwo endpanels 3| and 32 connected thereto along parallellinesoffold.

33 and 34.. These endpanels 3I and.. 32 comprise approximately one-quarter ofthe area of the panel 30so that when the outer sheet 29 is folded as illustrated in Figure 4 the panels 3I and 32. form a substantially semi-circular double thickness portion.

When the two

sheets

23 and 29 are folded as shown the

marginal edges

35 and 36 of the panels 26 and 2.1 respectively, abutl the vedges 3l and 39 of the panels 3| and 32. Accordingly a can bodyV is formed of three thicknesses of material which has no raw edges exposed either to the inside or to the outside of the body.

It will be noted that the can body material forming the liner of the wall is provided with two abutting

folds

24 and 25, while the outer covering sheet 29 is likewise provided with two abutting

folds

33 and 34. exposed to the outside In illustrating andy describing the. formation.

of they can bodies, thestructure shown in Figure V3 has been used as. an example. The: struci-i ture shown in Figure 2 is identical with that shown in Figure 3, except that the tape overlying the butting edges of the outer lamination is omitted. Similarly the construction shown in Figure 4 may be folded on the same mechanism as is used for folding the can wall B. In order to produce the wall C it is necessary to start the process described with sheets folded at 24, 25, 33, and 34. This folding operation may be separate from the operation shown in the drawings or may beV employed as a primary step in the 4production of the can wall bodies illustrated. The; manner ofi folding inwardly the ends of thel bodysheetsis well known in the art and maybe accomplished on folding machines well known to the trade.

With referencenow to Figures 5 and 6 of the drawings it willbe noted that the inner sheets I4- are stacked in feeding position in engagement with a suitable sheet feeding apparatus indicatedV by the numeral 40. This feeder 40 feeds each sheet successively beneath the sheet folding horn 4I. The folding horn 4I may comprise a series of spaced bars or wires, but is shown in its simplest form as comprising a sheet of metal or the like having downwardly and inwardly turned marginal. edges 42 thereupon. The mainbody of the folding horn 4I acts as a form about which vthe sheet is folded. The marginal edges 42 engage beneath the marginal edgesof each successive sheet I4 so as to fold the sheet to the shape of the folding horn 4I. As each sheet I4 enters the folding horn at its inlet end 43 the sheet is engaged by a lug 44 mountedgupon anendless conveyor belt or chain 45, This lug 44 moves the sheet I4 longitudinally of the folding horn 4I, the edges 42 of the horn acting to bendthe sheet into cylindrica l form asv it progresses. The lugs 44 are spaced and are synchronized with the feeding mechanism 40. The feeder 40 acts to urge the sheet into the folding horn far enough to permitthe same to be engaged by the lug.

Figure9 indicates the position of the sheet at thevlinev 9-9 of Figure 6. It will be noted that the sheethas been bent from its flat condition in which itwas stacked to slightly bent form. The sheet is` heldagainstthe folding horn by any suitable. means such as by guides which are notV illustrated, or" may beheld in place merely by contact with the endless belt or chain 45.

A folding horn 4I is supported by an inner tubular Vsupport 46 which is of a cantilever type. The inlet end 'of the support 46 is attached to any suitable supporting frame, While the outlet or discharge end of the apparatus is preferably entirely unsupported.

Figure v1() illustrates a successive step in the folding operation, this ligure being a section at the line I0--I0 of Figure 6. As will be noted in Figure l0 the folding of the sheet I4 has progressed considerably from the position of the sheet shownhin Figure 9. In the position shown in Figure 10, the inner sheet I4 has been raised about one-quarter of its final circular form. The

sheets I4 are preferablysupplied in position to travel longitudinally o f the grain of the paper as the sheets bend more easily with the grain running axially with the bend. The sheet continues to be driven by the lug 44. The center of the folding horn 4I may be slotted as indicated at 4T if it is desiredso that the extremity of the lug may extend well above the level of the sheet I4.

the sheetzbythelu. 1"

Figure 11 of the drawings illustrates a later step in the folding operation, this view being a section on the line II-II of Figure 6.V At this point of the bending operation the sides of the sheet I4 extend almost vertically and thus the sheet is wrapped almost into semi-circular formation Also shown in Figure 11 is the rst view ofthe outer lamination I1. This sheet I1 is positioned above the center support 46 and is later folded about the inner sheet I4 in such a Way as to overlie the rbutt joint between the longitudinal edges I5 and I6 of the sheet I4;

The sheets I1 are stacked in sheet feeding position above the level of the support 46 and are fed by the sheet feeding mechanism 49 into the inlet end 50 of the folding horn 5I. The folding horn 5I is arrangedl to fold the sheet I1 to overlie the sheets I4.

- The folding horn 5I is shaped somewhatsimilarly to the folding horn .4I, but it is inverted relative thereto. `The folding horn 5I` may be in the form of spaced bars or wires, but is shown in sheet formation. The folding horn 5I includes downwardly and inwardly extending ilanged edges 52 which form channels for re- 'ceiving the marginal edges I9 and 20 of the sheet I1.

A conveyor 53 is supported above the folding horn 5I to move the sheets I1 along the folding apparatus in unison with the sheets I4. The conveyor 53 is provided with a series of spaced lugs 54 thereupon which extend through a central slot 55 in the folding horn 5I. These lugs 54 are designed to engage the rear edge of one ofthe vsheets I1 as the sheet is inserted into the entrance end 5I) of the folding horn 5I by the feeding mechanism 49.

As will be noted in Figure 12 of the drawings when the sheet I4 is wrapped about slightly more than one-half the circumference of a cylinder the sheet I1 has been folded partially. The sheet I1 is carried along above the sheet I4 and is positioned sufficiently above the sheet I4 to permit the ends of this sheet to extend somewhat above the level of the support 46. The folding horn 4I is thus downwardly inclined as illustrated. If the support 46 is of suflicient length the sheet I4 may be entirely folded before the folding of the sheet I1 is started, in which event the folding horn 4I need not be downwardly inclined.

vFigure 13 illustrates diagrammatically the condition of the sheets I4 and I1 at a later stage in the folding operation. At this point the sheet I4 is almost entirely folded and the sheet I1 is wrapped about one-third of the circumference of a cylinder.

In Figure 14 the sheet I4 has been folded into circular form and the outer sheet I1 has been folded about one-half of the circumference thereof. It will be noted that the center portion of the sheet I1 is moving closer to the upper portion of the sheet I4 at this stage 4of the operation.

In Figure 15 the sheet I1 is illustrated as about two-thirds folded about the sheet I4 and closely approaching the same. carried along by their respective conveyors which may be either in'timed relation or arranged with the sheet I4 somewhat in advance of the sheet I1.

With reference now to Figure 16 of the drawings it will be noted that the sheet I1 is almost completely folded about the sheet I4. At about this stage of the operation the conveyor belt 45 Both sheets are being associes may terminate if desired and the two sheets may be carried inl unison' by the lugs 54 of the conveyor 53. Obviously in the event both conveyors are in timed relation, both conveyors may continue beyondthis point. However, in the event the sheet I4'is somewhat in advance of the sheet I 1 the sheet I4 will remain stationary for a short period' of time until the sheet I1 is in registry therewith whereupon both sheets will be carried in unison.

In order to adhere the two sheets firmly together the outer surface of the inner sheet I4 and/or the inner surface of the sheet I1 may be coated with a thermoplastic adhesive. When the sheets have been formed into encircling formation with one sheet bound tightly about the other as illustrated in Figure 17 of the drawings, these sheets maybe heated and pressed together so as to form a tight bond. This may be accomplished by any suitable means such as by providing a partition wall 56 inthe tubular support 46 and in providing steam through any suitable inlet such as the steam pipe 51. As a result the entire free end of the support 46 is heated to a temperature suicient to soften or melt the thermoplastic of the coating. This action tends to adhere the two sheets together under heat and pressure so as to form a secure -bond therebetween.

If it is desired a strip of tape may be applied over the butting edges of the outer sheet I1 s0 as to hold the sheets in proper relation during the cooling of the thermoplastic' adhesive. This tape 59 is supplied from a tape roll 60 and is applied by rollers such as 6I, one of which, 62, may if desired form a cutting roller which will cut the tape to the proper length. Alternatively the'steam chamber 63 between the partition 56 and the closed end 64 of the support 46 may be spaced from the'extreme end of the support so that the tubular body may be chilled before leaving the support 46.

As indicated at Figure 8 of the drawings the completed tubular bodies are carried o' the end of the support 46 and into any suitable conveying trough 65 or the like, or may be delivered to asuitable bin.

It will be noted that in our method we first fold the inner sheet either partially or entirely into cylindrical form and then fold the outer sheet about the inner sheet in such a way that the butt joints of the sheet edges are in angularly spaced relation. The sheets are then subjected to heat and pressure so as to adhere the same together, whereupon the tubular bodies may be released from the forming mandrel onto a suitable container or into a bin.

In accordance with the patent statutes, We have described the principles of construction and operation of our method and apparatus for forming paper 'can bodies, and while we have endeavored to set forth the best embodiments thereof,lwe desire to have it understood that obvious changes may be made Within the scope of 'w the following claims without departing from the spiritof our invention.

'We claim:

1. The method of forming a can body which includes the steps of moving .a flat sheet of a llength equal to that of the can body longitudinally. andlsimultaneously folding the sheet about a longitudinal axis, moving a, second sheet longitudinally and simultaneously folding the same about a longitudinal axis, the second sheet being 7` foldedl about the first sheet,A sheets iny tubular form.

' 2. Thev method, of forminga can bodyof thermoplastically coated sheets, havingv folded op;- nos'ed marginal ends. the method consistins Qi. folding one sheet into tubular form with the 'folded ends thereof outermost, folding a,` second sheet into tubular forni to` encircle the first sheet,v the folded ends thereof being innermost and abutting relationwith the, marginal ends of the rstsheet, and applying heat and pressure to the sheets to adhere the same together.

The method of formingv tubular walisfront spaced fiatv sheets of a length equal tothelength anni ademe said.

o fl the desired can body consisting-,in folding one4 sheety into tubularform so that` therends thereof are arranged in abutting relation.k moving, said.

sheet"longitudinally during the. folding` operation, moving a second sheet, in timed-l relatiqnA to said rstsheet, folding thesecond sheetv to en close the first sheet so that the ends ofthe second sheet are arranged in` abutting relation,l and securing the sheets together. I Y

4. The method of forming4 atubularbody from a pair or" flat sheets of a lengthequalvto the de,- sired length of the tubular body, the method con;-V sisting in moving one sheet longitudinally and simultaneously folding the sheet into tubular form with the ends thereof abutting, movingwa second sheet in timed relation with the first sheet and `with the ends thereof in registry, foldf ing the second sheet to overlie the abutting ends ofthe first sheet and to enclose the same, and securing the sheets together.

5. The method of forming atubular body from a pair of flat sheets of a` length equal, to the.v

length of the tubular body, the method4 consist: ing in moving one sheet longitudinally andV fold;- ing the ends thereof Yupwardly to form a tubular body, moving a second sheet in timed relation withthe first sheet so that the ends ofthe sheets are in registry, folding the ends of the second sheet downwardly to enclose the first sheet, and securing the sheets-in tubularform.

6. The method oflforminga/ can'body from a pair of sheets of a lengthequal-to the length of the tubular body, the method oonsisti-ngin folding the. ends of the sheets-upon themselvesto provide sheets of double. thick-ness yat theends', moving one sheet with the folded ends. under1y ing the adjacent portionL of the sheet,.folding the sheet into tubular forni so. that the foldedvv ends thereof lie outwardly of the.reniainderof, the sheet, movinga second sheet in timedrela,- tion to the rst sheet, folding the second sheet with the folded edges thereof innermost into.

tubular forni, the folded endsof vthe twosheets,v

forming an intermediate layer, between the remaining portions of the two sheets.

7. The method of forming a can body from` a,

pair of sheets having the longitudinal edges.V

thereof folded along parallel fold lines upon, the adjacent portionof the sheet, folding one sheetA into tubular form with the fold lines thereof,4 in abutting relation, and with the folded ends, of, the sheet lying outwardly of the remainder ofj the sheet, folding a. second sheet into tubularrfornr to enclose the first sheet withl thej fold'lnes thereof in abutting relation andthe folded ends thereof lying inwardly ofthe remainder of* the sheet, the folded ends ofA the two sheets forming intermediate iayerbetween the remainder oil the sheets; -1

of the sheet, folding the second sheet into tubular,

forml with the fold lines thereof abutting and with the ends thereof lying inwardly of the re.-y

mainder of the sheet, the folded ends, of; onesheet substantially abuttingv the folded, ends4 of the other. sheet to form a substantially continuous` intermediate layer betweenV the remaindexs. of; 'the sheets,

9. The'mcthcd o fyforming a can body from, a pair of sheets, which includes the steps of fold,- ing the` endsA of the sheetsalongparallel, fold lines so that they overlie adjacent portions` of the sheets, folding one sheet into; tubular form with the fold lines thereof abutting. and with the, folded ends lying outwardly of the remainder. ofthe sheet, folding, the second sheet into tubu lar form with the fold lines thereof abuttingv and with the ends thereof lying inwardly of the re mainder of the sheet, the folded ends of one sheet.` substantially abutting the folded ends of theI other sheet to form a substantially continuousintermediate layer between thel remainders,

of the sheets, and securing the; sheets inthis. tubular form.

10. The 4method of forming a hollow tubular wall which comprises moving longitudinally a.

the last named series about a longitudinal axis.:

andzabouta sheet of the first named series withA the; ends of the concentric sheets in registry,y

and adhering the sheets together.

- 11. The method of forming hollow tubular-crmY bodies from thermoplastically coated flat sheets which includes the steps of moving longitudinallyA a rst series of flat sheets-in spaced relation. and simultaneously folding the same into hollowI tubular'form about a longitudinal axis.l moving longitudinally a second series of flat sheets.- and simultaneously folding the, second sheets into hollow tubular form about a. longitudinal axis: and, about thev first mentioned'. sheet, the movement being timed to register the. ends,l of the. sheets, and applying heat and pressure to said sheets tov adhere the sameI together whilein hollow4v tubular finished form.

ROBERT M, DUNNING. REYNOLDS GUYER.

REFERENCES, CITED Thefollowingreferences are ofrecord' in the l'e ofl this patent: