US2796008A - Manufacture of envelopes - Google Patents

Description

June 18, 1957 1w. RANDALL MANUFACTURE OF ENVELQPES 4 Sheets-Sheet 1 Filed April 9, 1953 June 18, 1957 J. w. RANDALL MANUFACTURE OF ENVELOPES 4 Sheets-Sheet 2 Filed April 9, 1953 June 18, 1957 J. w. RANDALL 2,796,008

MANUFACTURE OF ENVELOPES Filed April 9, 1953 4 Sheets-Sheet 3 II III I] III" llllllll llllllllllllllllll IIIJTJIIIIIHI [inn June 18, 1957 J. w. RANDALL MANUFACTURE OF ENVELOPES 4 Sheets-Sheet 4 Filed April 9, 1953 United States PatentO MANUFACTURE OF EN VELOPES John William Randall, Boxmoor, Hemel Hempstead, England, assignor to John Dickinson & Co. Limited, Hemel Hempstead, England Application April 9, 1953, Serial No. 347,649 Claims priority, application Great Britain April 10, 1952 2 Claims. (Cl. 93-62) This invention relates to the manufacture of envelopes from pre-cut blanks and is more particularly concerned with the production of machine made self-sealing pocket type envelopes.

By pocket type envelopes is meant the kind produced by infolding the longitudinal marginal parts of a blank, which is usually rectangular, to provide lateral flaps which are secured together in overlapping relation to form, the back or rear Wall of the envelope while the ends of that part of the blank which lies between the lateral flaps and forms the front of the envelope are transversely folded over the lateral flaps to provide top and bottom end closure or sealing flaps. By self-sealing envelopes is meant that kind having the underface of the top sealing flap and the corresponding contact area of the back of the envelope provided with transverse stripes of latex or other self-adhering substance, which stripes adhere together without previous heating or moistening when the sealing flap is brought into contact with the back of the envelope.

Latex or other self-sealing adhesive employed upon envelopes of the kind with which this invention is concerned cannot conveniently or efiiciently be applied to the envelope surfaces by the known wipe-on gumming applicators and for this reason rotary applicators which rotate about axes extending at right angles to the direction of travel of the envelope blanks or envelopes formed therefrom are generally employed for the purpose. It has become customary, therefore, in envelope manufacturing machines as commonly used heretofore for the production of self-sealing pocket type envelopes wherein each blank is first carried through the machine with the fold lines of the lateral flaps extending in the direction of travel of the blank, to change the direction of travel of the blank after the said lateral flaps are infolded, so that it travels at right angles to the previous path of travel and the fold lines of the top and bottom'closure or sealing flaps extend in the direction of travel of the blank, thereby to enable stripes of self-sealing adhesive to be applied to the partly folded blank or completely folded envelope by rotary adhesive-applicators. The

conveyor means provided for abruptly changing the direc-' tion of travel of the blanks or envelopes considerably complicates the design and construction of the machine and leads to difiiculties in obtaining correct registration and alignment of the partly folded blanks or formed envelopes in the subsequent stages of completing themanufaoture and delivery of the envelopes.

Furthermore, owing to the limits imposed upon the width of the envelope blanks which are initially fed through the machine in the manner above set forth, it has hitherto been customary to make pocket type envelopes with the lateral'flaps which form'the rear wall thereof of unequal Width and to infold the wider lateral flap of the two as the first folding operation performed upon the blank. The infolding of the wider lateral flap in this manner and subsequent overlapping thereof by the narrower lateral flap considerably reduces the maxi- Patented June 18, 1957 mum uninterrupted area of the blank or formed envelope surface which is subsequently exposed for printing or other embellishment and thus appreciably reduces the amount of printing which can be applied to the outer faces of the formed envelope.

One object of this invention is to provide a modified and improved method of and apparatus for manufacturing self-sealing envelopes from blanks, whereby the application of the necessary self-sealing adhesive to the folded blanks or formed envelopes is facilitated.

Another object of this invention is to provide a modified and improved method of and apparatus for manufacturing self-sealing envelopes of the aforesaid pocket type from pre-formed blanks whereby the manner in which the blanks are fed and the sequence in which the folds are formed therein facilitate the application of the self-sealing adhesive to the formed envelopes and enable printing or other embellishments to be applied over a maximum area of the envelope faces.

According to one aspect of the present invention, provision is made of a method of manufacturing a machine made self-sealing pocket type envelope from a blank whereby the blank in passing through the envelopemaking machine is partly folded and a longitudinal seaming stripe and transverse bottom end sealing stripe of adhesive applied to the partly folded blank, whereafter the folding of the blank is continued to complete the envelope and the necessary self-sealing adhesive for the sealing of the top end closure or sealing flap is applied thereto, all of which operations are carried out whilst the blank and subsequently the envelope formed therefrom is constantly maintained with the fold lines of its lateral flaps extending at right angles to the direction of the travel of the blank or envelope.

According to another aspect of the present invention, in manufacturing a self-sealing pocket type envelope from a pre-formed blank, the blank is first folded to produce the narrower one of two lateral flaps of unequal widths which together subsequently form the back of the completed envelope and the once folded blank then progressed with the fold edges of the narrower lateral flap and subsequently formed wider lateral flap constantly maintained at right angles to the direction of travel of the blank, thereby to facilitate the application of printing or other embellishing matter to a maximum area of the outer faces of the blank and constantly maintain the top and bottom end closure or sealing flaps of the envelope extended in the direction of travel of the blank to enable self-sealing adhesive to be applied in transverse stripes to the under surface of the top end closure or sealing flap and corresponding contact area of the lateral flaps forming the rear Wall of the completed envelope by rotary adhesive applicators.

The apparatus for carrying the method of this invention into efiect may comprise means for adjusting the rotary adhesive applicators so that the self-sealing adhes'ive is applied in stripes of substantially even thickness, irrespective of the dilference in the levels of the envelope faces to which the adhesive is applied, while means may be provided whereby the adhesive applicators are caused to moveclear of the envelope faces when the apparatus is stopped while an envelope is in register with the adhesive applicators.

The method of this invention and apparatus for carrying the method into effect will hereinafter be further described, by way of example and without implied limitation of the scope of the invention, with reference to the accompanying drawings in which:

Figs. 1 and 2 together represent a diagrammatic side elevational layout of a machine for producing self-sealing pocket type envelopes by the method of this invention;

Figs. 3 and 4 are fragmentary detail views of the latexapplying section of the machine; drawn to a larger scale;

Fig. is a fragmentary detail view of the second lateral flap folding section in an alternative operating position; drawn to a larger scale;

Fig' 6 is a plan view of the pre-formed blank from which the envelope is formed in passing through the machine shown in Figs. 1 and 2;

Figs. 7 and 8 show the first and second stages of the blank folding operation to form the envelope therefrom, and

Fig. 9 is a view of the formed envelope with the top end closure flap open.

Referring to Figs. 1 and 2 of the drawings as a whole, the machine blank comprises feeding means of the roller folding type whereby blanks B, shaped as shown in Fig. 6, are arranged in a stack 2 upon an inclined slotted Wad plate 1 and are withdrawn singly from the bottom of the stack by means of suction feed rollers 3 and 4, assisted when necessary by a third friction roller 5 and arranged to buckle each blank outwards through a slot 6 in the inclined wad plate 1 and to pass the outwardly buckled blank between said feed rollers 3 and 4 so as to fold the blank along one longitudinal margin thereof to form the first lateral fold 7 and lateral flap 8 of the envelope. The wad plate 1 may be made in two separate parts which are relatively adjustable to vary the effective width of the slot 6.

The stacked blanks B are disposed in relation to the suction feed rollers 3 and 4 so that the first fold 7 created by the feed rollers forms a longitudinal edge of the front face 9 of the envelope and produce the narrower lateral flap. Thus, the blank will travel from the feed rollers 3 and 4 with the fold edge 7 leading and extending at right angles to the direction of its travel and with the end edges of the blank extending longitudinally in the said direction of travel. By this arrangement, a large part of the area of the blank forming the front and rear walls of the envelope will be exposed as an uninterrupted surface for the application of printed text or other embellishment thereto as desired.

The once folded blank B is withdrawn from the suction feed rollers 3 and 4 by co-operating pairs of racing forwarding rollers 10 driven at a higher peripheral speed than that of the suction feed rollers, whereby the blank is snatched clear of the feed rollers so as not to impede the withdrawal and first folding of the next blank withdrawn from the bottom of the stack 2 and through the plate 1. The once folded blank is then advanced at the increased speed towards a registering device comprising, in the example shown, a co-operating pair of inversely rotating register rollers 11, carrying register stops 12 which are periodically brought across the path of travel of the blanks B so that the leading fold edge 7 of each blank is held against the stops 12 and the blank thus registered in relation to the printing and impression cylinders 13, 14 respectively of a rotary printing unit 15. After registration, each blank is passed by forwarding rollers 17 between the printing and impression cylinders which may be arranged for printing over a part of or substantially the entire area of the outer face of the unfolded surface of the part folded blank presented thereto, i. e. the outer faces of the area 9, 16, 38 and 39 of the blank shown in Fig. 7. To enable the printing impressions to be taken very near to the bottom edge of the once folded blank, the impression cylinder -14 may be of the known suction type and arranged to seize the blank initially near its leading fold edge 7 and to draw it past the printing cylinder 14 and thereafter present the leading edge of the printed part-folded blank to a (to-operating pair of forwarding rollers 17a.

The forwarding rollers 17a are arranged to advance the printed blank to blank-creasing means comprising a nose, tail and side creaser roller 18 and co-operating creaser anvil roller 19, whereby the blank is impressed with weakening or crease lines to define the longitudinal fold line 21 of the second and wider lateral flap 16 and the transverse fold lines 22 and 23 of the end closure of sealing flaps of the envelope (see Fig. 7).

The partly folded, printed and creased blank is thereafter progressed by further forwarding rollers 20 to an adhesive-applying station e. g. a gumming station, comprising a seam and tail gumming roller 24 to which adhesive is transferred from a bath 26 by transfer rollers 25, so that the blank in passing between the gumming roller 24 and co-operating anvil roller 27 receives longitudinal and transverse stripes of adhesive 28 and 29 for securing together the infolded lateral flaps and sealing the bottom end closure flap respectively when the folding of the blank is subsequently completed. The blank, when thus prepared, is forwarded to a lateral flap folding station where the second and wider lateral flap 16 is infolded to overlap the first infolded narrower lateral flap 8 and thus complete the back of the envelope, as shown in Fig. 8.

The said lateral flap folding station is constituted by a group of three co-operating rollers comprising a transfer roller 30, a forwarding roller 31 set above the transfer roller and a fold roller 32 set below the transfer roller to form therewith a transfer roller pair 30, 31 and a fold roller pair 30, 32; a folder plate 33 with reciprocating registering stops 34 and relatively movable fold patters 35. The fold patters 35 intermesh with the bars of a folder guide grid 36 and are mounted upon a pivotal carrier 37 which is periodically rocked by timing means (not shown) so that the fold patters rise to the position shown in Fig. 5 and are thereafter lowered to the position shown in Fig. l.

The partly folded blank is first carried between the transfer roller pair 30, 31 and projected on to the folder plate 33, so that the leading fold edge 7 :of the blank is brought against the registering stops 34 and beneath the guide grid 36 associated therewith, whilst the trailing part of the opposite longitudinal side of the blank is forwarded by the transfer roller pair and the suction holes in the transfer roller 30 seize the blank along the line of the fold and draw it towards the nip of the folding roller pair 30 and 32 as shown in Fig. 5. The fold patters 35, which are raised when the blank is fed against the stops 34, are then caused to descend and assist in this movement and the stops 34 move forward to urge the blank forward into the nip of the folding roller pair 30, 32 to consolidate the second lateral flap fold as the blank is passed between the roller pair.

The twice folded blank, when thus passed between the fold roller pair, is formed as a flattened tube with outwardly projecting bottom and top end closure or sealing flaps 38 and 39 respectively and is thereafter engaged between a series of co-operating pairs of forwarding rollers 40 and 40a so as to travel along a path which is set at an acute angle to the previous path of travel of the blank. Even so, the blank continues to travel with its longitudinal fold edges and lateral flaps at right angles to its direction of movement, as indicated by the arrow in Fig. 8, and the top and bottom end closure or sealing flaps thereof extending longitudinally in the said direction of movement, the only difference being that the second folded longitudinal edge 21 of the twice folded blank has become its leading edge and the first folded longitudinal edge 7 is now the trailing edge.

A plough device in the form of a suitably curved plate or rail, is arranged in the path of travel of the twice folded blank to engage and fold over the bottom end closure or sealing flap 38 about its predetermined fold line 22 and the sealing of the said end closure flap to the back surface of the envelope body, i. e. to the outer surface of the lateral flaps, by means of the transverse stripe of gum or other adhesive which has previously been applied as above described, is consolidated by passing the folded over end of the envelope beneath suitable irongreases ing rolls 41 (see Fig. 3). The end flap folding plough means may conveniently be made adjustable to suit various sizes of envelopes which can be produced in a machine of the kind described. i

The formed envelope is conveyed, with its top end closure flap open and extending from the ironing rolls 41 through forwarding rollers '46 to endless conveyor tapes 47 which carry the envelope around an anvil roller 48 and between the latter and suitablerco-operatin'g adhesive applicator rollers 43 which are arranged to receive .a suitable self-sealing adhesive from a bath or trough 44 and transfer the adhesive as a film of any desired thickness to selected areas of the back of the envelope and the undersurface of the top end closure flap thereof. The self-sealing adhesive may, with advantage be a suitable latex preparation and will hereinafter be referred to as latex.

The endless conveyor tapes 47 extend across the body of the envelope and are suitably positioned to leave clear the area of the rear flaps 8. and 16 of the envelope and under surface of the top end closure or sealing flap to which the latex is to be applied. The latex applicator rollers 43 rotate continuously in the trough or bath 44 containing the latex at a speed slightly in excess of the travelling speed of the envelopes and against the direction of travel of the latter. Doctor blade means 49 are provided to remove surplus latex from the rollers 43, each of which is journaled upon a spindle 51 carried at the free ends of a pair of levers 50. 'Each pair of levers 50 is carried upon a rock shaft 52.

The rock shaft 52 has adjustably fixed thereto a cam lever 53 carrying at its free end a cam follower 54 which tracks the cammed edge of a cam disc 55 mounted to rotate about an axis of rotation of the anvil-roller 48. Springs 56 resiliently hold the cam followers 54 in tracking engagement with the cam discs 55.

Thus, as the envelopes are each fed between the anvil roller andconveyor tapes, the rotating cam discs 55 operate to rock the cam levers 53 and rock shafts 52 intermittently and thus permit the applicator rollers 43 to apply to the envelope latex stripes 45 of limited length which may suitably terminate at each end short of the longitudinal edges of the envelope, as shown in Fig. 9.

In the application of the transverse strips 45 of selfsealing latex to the backs of the pocket type envelopes and the undersides of their top end closures or sealing flaps, there has hitherto been a drawback in that the overlapping flaps of the envelope produce a stepped surface which leads to the deposit of stripes of latex of varying thicknesses which are different to the thickness of the stripe or stripes applied to the closure flap itself. Accordingly, the present invention has among its objects to overcome this drawback firstly by folding the wider lateral flap of the envelope over the narrower lateral flap thereof to provide a substantially level uninterrupted surface across the major part of the width of the envelope, as above described.

Furthermore, to guard against the inadvertent adherence of the latex applicator rollers to the envelope surfaces in the event of the machine stopping when the applicator rollers are in contact with the envelope, automatically acting cut-out means are provided for lifting the latex applicator rollers from contact with the envelope registered therewith when the machine stops, thereby preventing damage to the envelopes and dislocation of the operation of the re-started machine due to the build-up of latex between the applicator rollers and the envelope. In the example shown, such cut-out means comprise a bell crank lever 57 pivoted upon a rock shaft 52 and having one arm thereof arranged to engage a pin 58 projecting from the cam lever 53. The second arm of the bell crank lever is linked to a rod 59 which is connected in any suitable manner to the driving mechanism or driving control of the machine so that the rod is displaced to rock the bell crank in clockwise direction, as viewed in Fig. 3, and thus engage the pin 58 to rock the cam lever 53 outwards and thus withdraw the rollers 43 from contact with the envelope registered therewith when the machine stops.

Each completed envelope, i. e. each blank when completely folded and bearing the requisite stripes of latex upon the top end closure or sealing flap thereof, as shown in Fig. 8, will be engaged between juxtaposed stretches of endless conveyor tapes 47 and 59a arranged to carry the envelope around a direction breaking roller 60 to the feed-in rollers 61, 62 of an adhesive-drying or setting zone. Endless conveyor tapes 73a pass around the roller 62 and an associated roller 73 spaced therefrom and serve to carry the envelopes from the feed-in rollers 61, 62 towards an upwardly extending drying conveyor. The drying convey-or comprises an endless conveyor chain 63 carried around sprockets 64, 65 which rotate upon substantially horizontal spindles 66, 67 respectively mounted in vertically spaced relation in a drying frame structure 68, so that the conveyor chain has straight stretches extending between the spaced apart sprockets 64, 65 and travels in a closed circuit in a substantially vertical plane.

The said endless conveyor chain 63 has co-operating pairs of gripper fingers 69 attached thereto and adapted to be parted at predetermined envelope receiving and releasing positions along the straight stretches of the path of travel of the chain and grippers, so that each pair of parted gripper fingers receives an envelope therebetween :at the lower end of the upward path of travel and thereafter are brought together so that the envelope placed therebetween is firmly gripped and conveyed through the drying zone, while the gripper fingers are again parted in the downward path of travel through the drying zone to release the envelope gripped therebetween.

The gripper fingers are momentarily parted for the purpose of receiving or releasing the envelopes by passing the conveyor chain around sprockets 64, 71, as shown, or other guide deflecting means appropriately disposed along the substantially straight stretches of conveyor chain which pass through the drying zone, so that the gripper fingers follow a curved path at the offsetting points and are parted as they radiate from the radial point of the curved path.

It is, at present, preferred to make the gripper fingers U-shape in cross section at the envelope-carrying ends thereof and to fit them with resilient, e. g. rubber, pads to ensure a firm but resilient gripping of the envelopes inserted between the pads.

Stationary, but adjustable, registering stop devices 72 are provided to limit the inward movement of the envelopes in entering between the parted gripper fingers 69 at the receiving position at the lower end of the endless conveyor chain 63. The gripper fingers are parted for a time just suflicient to permit the envelopes to be passed one by one from the discharge ends of the said conveyor tapes 47, 59a and between the forwarding rollers 61, 62 and each brought into position against the registering stops 72 and between a pair of the parted gripper fingers by the endless transfer conveyor tapes 73a. The endless conveyor tapes 73a have associated therewith a reciprocating roller 74 adjusted to feed the envelopes forward one by one towards the gripper fingers 69 in timed relation to the travel of the conveyor chain 63 and gripper fingers carried thereon, thus to place each individual envelope between a diiferent pair of the gripper fingers.

The envelopes are removed from between the parted gripper fingers at the releasing position 76 by pivoted ejectors or pushers 77 which are actuated by rotary timing cam means 78 to push each envelope in turn from between the parted gripper fingers and bring it into engagement with a cam-operated or cam-tied swinging suction tube 79 which is adapted to feed the envelopes so removed to forwarding rollers 80 and a stacking cylinder .avoaoos 81 which counts the envelopes and stacks them in batches upon a travelling band 82 in known manner.

What we claim is:

1. Apparatus for manufacturing a self-sealing pocket type envelope from a pro-formed blank having opposite lateral flaps together substantially forming the back of the completed envelope, having a buckle-folding station comprising co-operating pairs of transfer and fold rollers respectively, one of each pair being a suction roller, a folder plate with reciprocating registering stops and relatively movable fold patters, the parts being arranged so that the once folded blank is fed from between the transfer roller pair on to the folder plate with the leading fold edge of the blank abutting the registering stops and the fold patters and the registering stops then moved first to assist the suction transfer roller in making the second fold and thereafter to introduce the second lateral flap fold edge into the nip of the fold roller pair so that the blank passes between the latter to consolidate the second lateral flap fold, an adhesive-applying station for applying selfsealing adhesive to the partially folded envelope, comprising rotary applicator means carried by pivotal arms arranged to be rocked so that the applicator means periodically make and break contact with the fully folded blanks or formed envelopes passed between the adhesive applicator means and a co-operating rotary impression surface, a lever arranged to deflect the pivotal arms and so displace the applicator means from the operative adhesiveapplying position, and means for linking the lever to an over-riding control of the apparatus so that the lever is rocked to deflect the adhesive-applicator means when the apparatus ceases to function.

2. Apparatus for manufacturing a self-sealing pocket type envelope from a pre-forrned blank having opposite lateral flaps together substantially forming the back of the completed envelope, having a buckle-folding station comprising co-operating pairs of transfer and fold rollers respectively, one of each pair being a suction roller, a folder plate with reciprocating registering stops and relatively movable fold patters, the parts being arranged so that the once folded blank is fed from between the transfer roller pair onto the folder plate with the leading fold edge of theblank abutting the registering stops and the fold patters and the registering stops then moved first to assist the suction transfer roller in making the second fold and thereafter to introduce the second lateral flap fold edge into the nip of the fold roller pair so that the blank passes between the latter to consolidate the second lateral flap fold, a self-sealing adhesive applying station for the partially folded envelopes, comprising a pair of rotary adhesive applicators carried by rocker arms so as periodically to move into contact with the fully folded blanks passed between the adhesive applicators and a cooperating rotary impression surface, rotary cam means for separately timing the operative movements of the individual adhesive applicators and arranged so that the operative movements of the said applicators can be individually varied to accommodate difference in the levels of the envelope faces contacted thereby.

References Cited in the file of this patent UNITED STATES PATENTS 1,807,867 Novick June 2, 1931 2,078,188 Winkler et al. Apr. 20, 1937 2,098,970 Novick Nov. 16, 1937 2,119,951 Dunnebier June 7, 1938 2,123,548 Sauerman July 12, 1938 2,132,227 Winkler et al. Oct. 4, 1938 2,151,665 Roloff Mar. 21, 1939 2,163,038 Heywood June 20, 1939 2,198,066 Staude Apr. 23, 1940 2,210,298 Kroch et al Aug. 6, 1940 2,307,907 Becker Jan. 12, 1943 2,406,205 Davidson et al. Aug. 20, 1946 2,612,088 Heywood Sept. 30, 1952 H FOREIGN PATENTS Y Great Britain Jan. 10, 1951

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