US 2774286 A
Description (OCR text may contain errors)
Dec. 18, 1956 Filed Ma'rcl; 1a, 1952 L. E. LA BOMBARD MACHINE AND METHOD FOR FOLDING BOX BLANKS 6 Sheets-Sheet 1 Fig. 1.
BOMBARD Dec. 18, 1956 E. LA BOMBARD 2,774,286
MACHINE AND METHOD FOR FOLDING BOX BLANKS 6 Sheets-Sheet 2 Filed March 18, 1952 ht Q a? mi INVENTOR. LEON E! LABOMBARD Dec. 18. 1956 L. E. LA BOMBARD 2,774,286
MACHINE AND METHOD FOR FOLDING BOX BLANKS Filed March 1 8, 1952 6 Sheets-Sheet 3 INVENTOR. LEQN E. LABOMBARD Dec. 18, 1956 L. E. LA BOMBARD 2,774,286
MACHINE AND METHOD FOR FOLDING BOX BLANKS Filed March 18, 1952 6 Sheets-Sheet 4 ulm 150 134 154 "A 4/ 133 INVEN TOR. LEON E LABOMBARD 7 W EM Dec. 18, 1956 E. LA BOMBARD 2,774,286
MACHINE AND METHOD FOR FOLDING BOX BLANKS Filed March 18, 1952 6 Sheets-Sheet 5 I 3 I 45 11 A3238 F1910. P
INI 'E.\' TOR. LEON E. LABOMBARD ww nr 1956 L. E. LA BOMBARD 2,774,285
MACHINE AND METHOD FOR FOLDING BOX BLANKS Filed March 18, 1952 6 Sheets-Sheet 6 F D I 0 X I:
- 514- D 4 INVENTOR. w .9 5 LEONELABOMBARD 562501 i BY :53 K85 TM F R 652 1 524, F"
United States Patent MACHINE AND NIETHOD FOR FOLDING BOX BLANKS Leon E. La Bombard, Nashua, N. H., assignor to International Paper Box Machine Company, Nashua, N. H., acorporation of New Hampshire Application March 18, 1952, Serial No. 277,242
Claims. (Cl. 93-49) This invention relates to an improved method and apparatus for infolding the leading or trailing flaps of a fiat box blank as the blank travels along the paper line of a box folding machine. It is particularly useful in folding blanks having a large number of leading flaps each of considerable length longitudinally such as are found on the Himes type box, well known in the trade. instead one or two comparatively short and wide leading flaps, boxes of the Himes type present four long, narrow flaps which are difficult to infold on high speed machinery. Furthermore two of the leading flaps on such boxes are usually wide and include a diagonally articuiated sealing tab to be bent in a direction opposite to in- Y folding, while being infolded, and therefore have different folding characteristics from the other two narrower flaps.
Various methods have heretofore been proposed for infolding the leading flaps of a box blank for example the prebreaking of all flaps upwardly, at one station on the paper line, and the infolding of such upwardly bent flaps, at a second station on the paper line, by placing a stationary obstruction in their path, above the paper line. My invention eliminates the preliminary upfolding station and its mechanism and folds each flap from a fiatwise position .in extension of the blank to an infolded position all at the same station on the paper line. In my device one or more of the leading flaps of the same type are completely infolded at a first station, while the remaining flaps are held down on the paper line. The remaining flaps of another type are completely infolded at a second station, while the first infolded flaps are in turn helddown on the paper line.
Methods have previously been proposed for infolding a fiat leading flap at a single station. One such method comprises the use of a fixed, upstanding, spring on the paper line arranged to exert pressure from underneath the flap to lift it into contact with a fixed obstruction positioned above the paper line. Another such method has been the use of an arm, pivoted below the paper line, which advances with the blank as it pivots to fold the flap. Another such method includes the use of an arm, pivoted at a fixed position above the paper line, which kicks the flap upwardly from a pivot point in advance. of the flap. The devices used in such methods have certain disadvantages in that a spring is impositive and-may wear out, a stationary pivoted arm may fracture the flap at high speeds and an arm pivoted below the paper line but advancing with the blank, involves considerable mechanism to hold the blank down during folding.
One object of my invention is to provide means for infolding a leading or trailing flap of a flat box'blank, as it travels along the paper .line of a folding machine, without the necessity of a separate station for pro-breaking and pre-bending such flaps upwardly. A further object of my invention is to infold all leading flaps of one type at one station and all those of another type at another station, and/ or to similarly infold the trailing flaps, the infolding mechanism at each station being positive at 2,774,286 Patented Dec. 18, 1956 2 high speeds and having no complicated mechanical 7 age between the flap upfolding and blank hold-down mechanism.
' Another object of my invention is 'to provide a rigid guide for applying a gradually increasing upward pressure under the leading edge of each leading flap or the trailing edge of each trailing'flap as it moves along the paper line thus urging the flap to bow and then to bend at its line of articulation, combined with an elficient hold down member applied to the part of the blank to'which the flap is articulated. Still another object of my invention is to provide a member pivotally mounted above the paper line and provided with a longitudinally extending surface, which surface moves from a flatwise position beneath one portion of the paper line to an inclined position above another further advanced portion of the paper line thereby upfolding each leading or trailing flap accurately into engagement with a stationary back-folding member. Another object of my. invention is to associate with such a pivotally mounted member, a similarly pivoted hold-down arm for use in holding down the adjacent portions of blanks of less bendable material.
in the drawings,
Fig. 1 is a side elevation partly in section ofa folding machine constructed in accordance with my invention to fold the leading fiaps of an advancing blank.
Fig. 2 is a plan in Fig. 1. v g 7 Figs. 37 are each enlarged side elevations of my new pivoted flap-uplifting and blank hold-down mechanism and my stationary infolding member in various stages of infolding a leading flap of an advancing blank. 7
Figs. 81O are each enlarged side elevations of my new pivoted flap-uplifting mechanism and my stationary infolding member in various stages of infolding a leading flap of an advancing blank of material not requiring any blank hold-downmechanism.
Fig. 11 is an enlarged side elevation showing my invention in combination with a folding bar arranged to back fold a diagonally articulated tab on the flap.
Fig. 12 is an enlarged view of the blank shown in Fig. 2.
Fig. 13 is a view of an erected box made from the blank shown in the drawing. f p
Fig. 14 is a fragmentary side elevation partly in section of a folding machine constructed in accordance with my invention to fold the trailing flaps of an advancing blank.
Figs. 15-18 are each enlarged fragmentary side elevations of the folding mechanism of Fig, 14 in various stages of infolding a trailing flap of an advancing blank.
Fig. 19 is a fragmentary rear view of the pivot portion of the mechanism shown in Figs. 14-18. I j
As shown inFigs. l2 and 13, A represents one formiof blank for which my invention is especially adapted, namely a blank of the Himes type, although it should be noted that my folding mechanism and method is useful in folding the leading or trailing flaps of blanks of many other types. Blank A has two end wall panels 20 and 22, two side wall panels 21 and 23 and a wall sealing tab 251', which is articulated to side wall panel 23.. It is'also provided with cover panels 25, 26 and 27 connected to 34' is formed in flap 31 by a diagonal line of articulation I 37 and a'bottomsealing 'tab35 is formed in flap 3 view of the folding machine illustrated V V tvey :77 a dia gonaljli'ne of articulation lfad." suitable slits cnt-t otitsjand lines of articulation, wll known in the trade; are A we panesand T211118 B oldinginachine in afl at wise, horizontal posh' of articulation 3 8 'intg infolded position overlying side I t e @55 0, 31, 2211 1 leading th blank wa lp nels 2.1 amt lirassh in a ssiat B The i sii 1th=the1hnes of articulation28 and 38, transverse for the pre-broke n hottornjsealing tabs Sigr d-$5,111 a to eidir el onfof'travel oii the bla nk. The principal direction opp0site v tothedir ectipn offolding of fiaps31 se ofi i nyisfolding-machineis to infold leading flaps t 1 m h Tinq -ugi r fi ing Q av ng tu ppprtstfiiil; ifland having trpstandin g" side plates feeding toldihgand rnechanisrn of my. machine is a l y :IOds, or shafts extending between side plates suchas il ancl'fl l so that all of the parts can be'fi'xed in the correct transverse position to accomrno-i datelhlanks ofqdiiierent sizesfand shapes Similarly" all i vvtimitat l ;ti 9 my m e inea o n cte y sintable "gears, hells; or chains }so :that-they operate-in synchronizationarid, are suitably powered from a source not shaman a manner not shown in' detail sinceitjs bx tblanks sgnchfasiA are advanced along the paper;
zfiandfto't fold'tabs 34 and 35 on linesloftarticulation 3 6-ar1d 3'1 so that the blank '32 of a blank such as A p e-broken downwardly-t-on lines of articulation 37 and 36 also at this Qstation.) At" tion 209, the second sta-- 7 tion, the flat leading ilaps}ligand: 31 of a hlank suchas "A are bent upwardlyand then backwardly on the line and 33; commences at' station 258" and is completed At the first station 100, I provide a pair of endless carriedcnsprockets as ltllon transverse shafts 104 and 105 102 are1each aligned above t '5 one oli'the endless conveyors D and e achfis 'adjustahle toi jvariou s transverse .p'osition s 'in the same manner as is ach'conveyor D Leading flap 31, side wall panel 21] and cover panel zfiare thus advanced through station 100: by a lug; 45 ;ofa conveyor DQwhile supported frontbelow by the conveyor 'd'helil down onfthef paper line P by J hold down chain: 101 Leading. flaps '-and 32 are supported from below byrfothejr, conveyors such as Debut since lthere is nohol d down chain above these fiaps; at
stationjiilljl space is availableabove the paper line a l fgr lfolt lingjrneehanism to be described hereinafter.
also formed in blank A, as shown in Figs. 1 and} whereposition overlying side wall panels 20 and 22 as shown: j
' 'hyt-thetblanlg can he t'or mecl intqthe'collapsedbox at B. e a Q 7 V 7 in V itheh foldedbetween the wall 5 For convenience the bottoni: sea1ing tabs 34 and 35 are 39,131, 32 and 3439f alblanksnch asA'on their 15 shortly after the completion oi the'inf olding of flaps 31 V ;ul'ation: 3.3 to. overlie the side Wall panels 20, and 33. t
hold-down chains 101, 102 each chain such as lilltbeing t r 7 well lgndw rrin thef trade. -V a V V @As shown in Figs; 1 and Z-an V m Wh m" 3 1 a l ll l P3 1 6 D lQ lC DWYQ S h m atically inrFi gs.'3-7',1rny folding mechanism includesa aronnd, arr anged to receiveand advaricea blank along "len th y-mahlfiebe e he eeq nem h n m.
' p a and the, mechanism G, and is traificfil' 3 0 4 95 1 X x ex d a upp on a longitndina 4 WhlCl], s ersely 'on rods or P111 51 bf me yit e PP we i f he 15 Eachco eyor-D extends substantially the V,
rigidiar n 1 10, bent at 111 toforrn' an elongated fiap -up lifting; finger 112 ,Arnrllfli is rotatably monntedfat 15 1 on a powered shaft 113,10 revolve on an axiszabove and transverse to thelpape riline B andin a vertical plane getpe dicu ar to hen ane f sa d. P p line, Finger .12 9,
' r a ig d P e, styai h fa er rt nr el i h c is P f? posrti Q to p ositi'onit"finder a particnlar flap such as 30, 3:1;32
r r 5 ,"E va Q9 1Y$ibiw tl 4 t sup ort. an r, PPHQeAl-Qa t at emQYel ran e y t emaqh r he 'r id Blane-suede 4 52 describe p la pa' hi around the; shaft 113,; located above 'the paper line P, i
V an .13s4 949}? 9 uPP9 a nce la k u h V A through the'folding mechanism 1;? without interfering i h-the t a iqldia amembete w ich xten lgel r r the: portion. of Y the path proximate the paper line being'in line -asindicaltedihylthe arrows, but-the rate of advance [if being less than that of the blan' kslfl'l preferto use twoj flap of a blank; advancing on the paper line,
ea i x l ia r h f-gthe.ma hin kb eieen l r I jglpihg mecha nd a h o r u h}?! e ar' taqk 9i" blanks e d ng 50118 4 arr es to ed b a k V a rtime from the staclcpnto conveyors; D where V fby-l s 4, n ia hr n hr t e E nd; e l inahie hamsni G initimes 7 although ti'swobviousthatnrore orcless 'arrris'can he used I as desi a e I I? 7 7-111 is i ls c a blank 9 ,A w ha a n ap 36, =sidewall panel 2fl and cover panelr25 all in fiatwise V 7 'o m i ap i'l e and;he a afi edih eale e'- 1 infthe dir ectienjlof the.arrows;v Conveyors; D hold V A z downchain 101 are nie ely indicatedsince at this firstrstaf t r l a ed e n. nclu a" P 1 i-l l 'fe ga epa els..a cg pa hichw l flfi i e ll i 51 h Pslidably c ln cdia n' a 9 hbtibejffolded and are clearly shqwrifiigsl aria 2.15
ci haft '62 and havingj suitableglne snpply r'olls' i I The; igid; lilane flat straight surface 1140f flapdiplift-g ot's indicated at Gluel rolls 6 4 are arranged to a dep a a f a F ta fad e n he. ba k; l,me V..;;-
l a -g3 r d' '0 a la 9 a h-s52" e yelvsewreirtq her c 14 1 9 1 l fili li hewa flames-: 2 5 4 1 ppositely; disposed pressnre'rolls sideep tes.;40l and 41 are" provided to iron out the'folds ingQfiiigerI 112i isgsiihstantiallywghorizontal, justihelowlthei V Qiqfiidhi? folding mechanisrnF-pfrior to arrival lat 'snchas, and having a downwardly tapeted unders a f,
'chanisna is the-essenc of this invention e 8. m he f l i in take place at twmstations indicated overlie its side wall panel such as 20 when it has been advanced to the end 134 of member 130. 'Ihe first folding station thus extends from the point on the paper line at which the undersnrface of flap 30 is contacted by the rigid plane surface 114 of finger 112, shown in Fig. 3 to that point on the paper line under the end 134 of the stationary infolding member 130.
Also included in myfolding mechanism is a rigid holddown arm 150, rotatably mounted at 151 on powered shaft 113 to revolve with arm 110 on the same axis and in the same plane relative to the paper line P. Each arm 150 maybe fixed in a predetermined angular position relative to the arm 110, with which it cooperates, by a set screw 152, and if not needed due to thecharacteristics of the paperboard of'the blank, or the conformation of the leading flaps of the blanks it may be revolved flush with arm 110as shown in Figs. 8-11. As shown in Figs. 3-7, however arm 159 is adjusted to follow arm 110 so that the tip 154 of arm 150 will contact the upper surface of the panel 20 to which the leading flap 30 is articulated, just behind the line of articulation 38 while arm 110 is uplifting flap 30.
In Fig. 4, the blank A is shown in an advanced position on paper line P and arms 110 and 150 are also shown in advanced positions on their respective circular paths. However, since arms 110 and 150 advance at a less rate of speed than the blank A, the undersurface 39 of the leading flap 30 has slid up the rigid plane surface 114 of the gradually inclining flap-uplifting finger 112. At this point the blank A is being held down on the paper line P by hold-down chains 101 and 102 'which are laterally spaced from fiaps 30 and the tip 154 of hold-down arm 150 has not yet contacted the upper surface of panel 20 so that the flap 30 and panel 20 may be inclined or bowed upwardly as indicated in Fig. 4.
In Fig. 5 the blank A is shown in a still further advanced position on the paper line? and arms 110 and 150 are correspondingly advanced in their circular paths. The less rate of advance of arm 110 has caused the undersurface39 of fiap 30 to slide still further up the rigid plane surface 114 of finger 112 and the tip 154 of arm 150 has contacted the upper surface of panel 20. If flap 30 had not already become upfolded on its line of articulation 38 by the lifting action of the rigid plane surface 114, the downward pressure of the tip 154 on panel will cause the flap to bend positively at the line 38.
In Fig. 6 the blank A has continued to advance along the paper line P and the rigid plane surface 114 of finger 112 has positively and accurately guided the leading edge offlap into the notch 131 of the stationary infolding member 130. At the same time the finger 112 and'the tip 154 of arm 150 have completed their upfolding function and are revolving out of the way.
In Fig. 7 the flap has continued to advance along the paper line P under the stationary infolding member 130 and the flap 30 is being gradually bent downwardly on its line of articulation 38 to overlie panel 20 by the undersurface 133 of member 130. Uplifting finger 112 and hold-down arm 150 have also advanced in their circular paths which carry them around centre of rotation 113 for a complete revoiution to repeat the operation on the leading flap of a succeeding blank.
Each stationary infolding member 130 is fixed at the lower end 136 of an arcuate member 137 and the upper end of member 137 is slidably mounted in a bracket 138 by means of set screws 135. The are of member 137 is concentric with the circular path of finger 112 and hold 7 down arm 110, so that if a flap of greater or lesser length is used 'on a blank such as A, it is only necessary to slide the arcuate member .137 upward or downward to the desired position in bracket 138. Each bracket 138 is slid able transversely on a rod 139 and each arm 110 and 150 s is also slidable transversely on shaft 113 to assumevarious positions in accordance with the location of the lead ing flaps on the blanks to be infolded.
f such station 500 in Figs. 14 to 19. It willbe under V I find it convenient to locate tab pro-breaking mechanism H at the first station, as shown in Figs. 1 and 2, because the leading flaps 31 and 33 to which the bottom sealing tabs 34 and 35 are articulated are firmly held between conveyors D and hold-down chains 101, 102 at this station. I provide an endless chain 170, having outwardly projecting lugs 171 therearound, each arranged to contact a tab such as 34 and bend it downwardly below the paper line P thus pre-breaking it on its line of articulation 37.. Chain is trained around sprockets'172,
173, journalled in a rigid support 174, which support depends from a transverse rod 175 and is slidably adjustable in various positions thereon by a set screw 176. Beneath the paper line P, under and diagonal to the path of lugs 171 of chain 170 I may place tab folding guides 177 to assist in prebreaking each tab such as 34.
After leading flaps such as 30 and 32 have been infolded and tabs such as 34 and 35 have been pro-broken at the first station 100, the blank A passes out from under hold-down chains 101 and 102 and while still being advanced by conveyors D, passes under a second pair of hold-down chains 201, 202. Hold-down chains 201 and 202 are in line with two infolded leading flaps 30 and 32 and serve to keep such flaps infolded as Well as to hold the blank down on the paper line P at the second folding station 200. Each hold-down chain, such as 201, is carried on sprockets such as 203 on transverse shafts 204 and 205, and is powered'and adjusted in a manner similar to that of chains 101, 102.
As shown in Figs. 8-ll, at the second station 200, I
provide a rotating uplifting finger 212 for each flap such 7 as 31 or 33 to be infolded at that station. I prefer to also use a rotating hold-down arm such as 150 with each finger 112 or 212 at each station, but since my rotating uplifting finger will lift and upfold flaps successfully without an arm such as 150 on very bendable material I have illustrated the action thereof in Figs. 8-ll. As shown in Fig. 8 a leading flap '33 of a blank such as A, with its bottom sealing tap 35 pro-broken downwardly contacts the rigid plane straight surface 214 of the elongated flap uplifting finger 212 with the undersurface 239 of the flap and it should be noted that surface 214 is substantially co-extensive in length with flap 33. In Fig. 9 the blank A has advanced along the paper line P so that flap 33 has slid upward along the surface 214 which is advancing at a less rate of speed than the blank but in the same direction. In Fig. 10 the blank has advanced still further along the paper line and the flap 33 has slid still further along the gradually inclining and rising surface 214 until the flap folds upwardly on its line of articulation 38. In Fig. 11 -I show the blankfurther advanced on the paper line P, the finger 212 releasing the flap 33 into the notch 231 of a stationary infolding member 230 which is identical with member 130. Bottom sealing tab 35 is shown being slidably engaged by a folding guide 260 which extends longitudinally of the paper line in a well known manner to backfold'the tab 35 as the flap 33 is infolded by undersurface 232 and 233 of member 230 to overlie side wall panel 23. Guides 260 are mountedfor lateral movement by means of a bracket 360, slid-able on a transverse rod 361. I
While my invention is especially useful for infolding the leading flaps of blanks advancing along a paper line, as shown in Figs. 14 to 19 it may also be used to infold the trailing flaps of such blanks. For example to infold a single trailing flap such as 26, or a pair of similar trailing flaps such as 25 and 27, of a blank such as A, I provide a folding mechanism M on frame C in place of folding mechanism F or in advance thereof. Preferably the infolding of different types of trailing flaps takes place at different stations but for illustration'I show only one stood that pre-breaking mechanism such as H, holddown chains such as 101, 102, 201 and 202 and folding face of the edge portion of a transversely articulated flap and being movable, by the rotation of said arm, to advance with said blank while assuming a gradually increasing angle of inclination to the paper line, and a holddown arm, fixed at a predetermined angular relation to said uplifting finger and mounted to rotate in a vertical plane around said axis of rotation, said holddown arm being arranged to press the main body of the blank down on the paper line after said flap is guided upwardly by said uplifting finger, thereby positively causing a fold at the line of flap articulation.
3. In a machine for use in making knockdown boxes; timed means for continuously advancing a flat boX blank at a predetermined speed along a straight, horizontal path through said machine with the lines of articulation of the longitudinally extending flaps thereof transverse to said blank path; a folding arm of rigid material, operable at a folding station along said blank path, said arm being angularly bent at one end to form a hook with an elongated straight plane inside face for slidably engaging a flap; timed means supporting the other end of said arm and moving the same continuously and unidirectionally in an endless, closed path above said blank path, said arm supporting means and arm being arranged to initially position the inside face of said hook under and parallel to the outer edge portion of a longitudinally extending flap of each successive blank advancing along said blank path and to advance with said flap along said path at a different rate of speed than that of the blank while sliding further under said flap and uplifting the same on its transverse line of articulation and a stationary flap infolding member mounted above said blank path at said folding station, said member receiving each successive uplifted flap from the hook of said arm and infolding the said flaps flatwise against the blank as the blank continues advancing thereunder.
4. in a folding machine, mechanism for folding the leading flaps of fiat articles, said mechanism comprising timed means for advancing a plurality of fiat articles individually and successively along a straight path through said machine with the lines of articulation of the leading flaps thereof transverse to said blank path; a rotatable, angularly hooked folding arm of rigid material mounted to rotate around a laterally extending axis of rotation above said blank path in a vertical plane longitudinally of said path, the hook portion of said arm trailing rearwardly thereof and being substantially coextensive in length with the length of a flap to be folded thereby and having a straight, flat, plane inside face for slidably engaging the under face of a flap and the shank of said arm being of greater length than the distance from said centre of rotation to the said blank path to position its trailing hook portion flatwise in supporting position under an advancing flap once during each revolution thereof and timed means, synchronized with said blank advancing means, and rotating said hooked arm in a closed, unidirectional, circular path, said means being adapted to present the straight flat face of said hook initially horizontally under each successive leading flap, to then advance and angularly incline said face while causing the flap to slide further along the face and be uplifted on its line of articulation and to then rotate said face through a complete reevolution back to its initial position.
5. A folding machine as specified in claim 4 plus a stationary, overfolding member fixed above the path of said blanks and in the path of a flap uplifted by the hook of said folding arm, said member having a rearward facing notch in the rearward edge thereof arranged to receive the leading edge of each successive uplifted leading flap and serve as a pivot point for forcing the said flap 10 to fold on its line of articulation before being overfolded by said member.
6. A folding machine as specified in cliam 4 plus a blank holddown arm rotatable with said folding arm around said centre of rotation but angularly spaced therebehind to press downwardly on the upper face of a blank behind the line of articulation of a leading flap after said hook has engaged and uplifted said flap thereby assisting in causing the flap to fold on its correct line of articulation.
7. A folding machine as specified in claim 5 wherein said stationary overfolding member is mounted on said machine for slidable adjustment on an arcuate member, the centre of the arc of said member being at the centre of rotation of said hooked folding arm.
8. Apparatus for upfolding the lea-ding flaps of fiat foldable articles, said apparatus comprising timed means for advancing a plurality of flat foldable articles individually and successively along a straight path with the line of fold of the leading flaps transverse to said path; a rotatable support mounted for rotation in a vertical longitudinal plane on an axis of rotation transverse to and above said path; at least one straight, flat, folding finger of rigid material carried by, and rotatable with said support, said finger being adapted to move from a position flatwise under and parallel to said article path to a position further advanced therealong, perpendicular to, and above, said path with each complete revolution of said rotatable support and timed means, synchronized with said article advancing means, for continuously and unidirectionally revolving said rotatable support with the horizontal component of advance of said finger, between the said positions, being at a predetermined less rate than the rate of advance of said articles whereby a leading flap slides along said finger as it is upfolded on its line of articulation.
9. Apparatus as specified in claim 8 wherein said straight flat finger is substantially co-extensive in length with the length of a flap to be upfolded thereby.
10. A rotary method for upfolding the longitudinally extending flaps of a plurality of flat box blanks advancing individually and successively along a longitudinal path at a predetermined rate of advance, said method comprising the steps of applying a rotary, mechanical, pulling force from above the path of said blanks and in an upward and rearward direction upon the under face of each said flap, and over an area of said under face progressively shifting inwardly longitudinally of the flap, while simultaneously holding down laterally removed portions of the body of the blank, until the flap and the portion of the blank to which it is articulated have been inclined upwardly out of the flat plane of the blank and then applying a rotary, mechanical, pushing force from above the path of said blanks and in a downward and forward direction upon the upper face of the main body of each said blank, just behind the said line of articulation to cause the flap to fold accurately on said line of articulation.
References Cited in the file of this patent UNITED STATES PATENTS 830,032 Wright Sept. 4, 1906 1,370,654 La Bombard Mar. 8, 1921 1,538,298 Nasmith May 19, 1925 1,974,408 Bergstein Sept. 25, 1934 2,048,729 Daller July 28, 1936 2,197,089 Anderson Apr. 16, 1940 2,291,063 Staude July 28, 1942 2,363,425 Klein Nov. 21, 1944 2,519,111 Chapman Aug. 15, 1950