Method of and Apparatus for Adhering Sheet Material Wrappings and the Like

The present invention relates to methods of and apparatus for adhering sheet material wrappings and the like, being more particularly directed to the adhesively secured wrapping of such material about cylindrical inserts, such as wrapping cigarette paper or paper substitutes (hereinafter sometimes termed "paper") about filter inserts.

Machines have heretofore been designed and employed for securing cylindrical or rod cigarette filter inserts, including dual or compounded sections of charcoal and cellulose fibers in plastic tubes and the like, within the cigarette, such as those of Hauni-Werke Korber & Co. of Hamburg, Germany, as described, for example, in its May 1976 Dual-Filter Machine Mulfi Bulletin. In accordance with such apparatus, dual filters, as of charcoal and plastic sections of cellulose fibers and the like, have been wrapped with filter wrapping paper to form a rod of successive charcoal and plastic sections, with the wrap adhered by a longitudinal seam of adhesive and with further adhesive regions attaching to the filter sections. The wrapped filter rod is transversely sliced to form the dual filters which are connected to the tobbacco element sticks or rods of the cigarette, as by tipping material sheets. Problems arising with such and similar apparatus include the building up of adhesive material from the wrapping sheet upon the slicers or cutters, and the often inadequate adhesion of the wrapping sheet to the filter sections, particularly when the end of the filter is chewed or unduly moistened.

An object of the present invention is to provide a new and improved method of and apparatus for adherently wrapping and cutting such multiple or other filter inserts that obviate the said problems, greatly reducing the deposition of adhesive on wrapped-filter cutters, and improving the holding action of the wrap upon the filter sections.

A further object is to provide such a novel wrapping and cutting technique that is also adapted for other types of inserts and wraps of more general application, as well, wherein the advantages or some of the advantages of the invention are sought.

Other and further objects will be explained hereinafter and are more particularly delineated in the appended claims. From one of its aspects, the invention, in summary, contemplates a method of wrapping substantially cylindrical inserts within sheet material, that comprises, forming the inserts and feeding the same along a line; feeding a web of the sheet material in the direction of said line to receive the inserts longitudinally thereupon; depositing upon the web prior to its receiving the inserts a longitudinal adhesive line near an edge of the web and succesive sets of longitudinally spaced transversely extending adhesive dots or dashes; controlling the longitudinal spacing between said sets of transversely extending adhesive dots or dashes to correspond to predetermined spaced regions along said inserts; transversely wrapping the adhesive-provided web about the inserts with sufficient overlap to enable securing along said longitudinal adhesive line and to adhere the successive sets of adhesive dots or dashes circumferentially to the inserts at said predetermined regions thereof; and transversely cutting said wrapped inserts synchronously with the presentation of spaces between said sets of adhesive dots or dashes to avoid cutting contact with the same. Preferred details and applications are later set forth.

The invention will now be described with reference to the accompanying drawing, the single FIGURE of which is a schematic isometric view of a preferred apparatus, illustrating the technique as applied to the cigarette filter application.

Referring to the drawing, pre-produced filter rods 1 and 2 (as of charcoal and plastic tubes of cellulose or the like), are schematically shown segmented (I), staggered (II), aligned (III), cut (IV) into desired filter lengths (say from 60 to 150 mm), and grouped (V) in abutting relationship 1-2. The groups 1-2 are turned (VI) and fed in-line (VII) longitudinally upon a wrapping paper or similar sheet web 3, all as described, for example, in said Hauni-Werke bulletin and elsewhere. It is to the improvement of the wrap of the web 3 in this conventional assembly that this invention is primarily directed.

The sheet material web 3 is shown drawn from a supply roll R to an adhesive-application section S (shown vertical), where successive hot melt or similar adhesive applicators 4 and 4' distribute controlled adhesive markings, as follows. The nozzle 4 receives hot melt adhesive via tube 5 from a metering pump 6 which also applies the adhesive by way of tube 5' to the upper transverse nozzle array 4', these structures being, for example, of the types described in our previous U.S. Letters Patent Nos. 3,595,204; 3,294,060; 3,323,510; and 3,174,689. The nozzle 4 produces a continuous longitudinal line or strip 3' of the adhesive near an edge of the web 3, whereas the transverse array of nozzles 4' is fed with metered pulses of hot-melt to generate a corresponding transverse array of adhesive dots 3", periodically applied, as described in said patents, and more particularly in U.S. Pat. No. 3,595,204. Preferably, the dots are deposited in sharply defined spots with the aid of a multiple-blade bumper element 7, periodically deflecting the web from the left side to contact and wipe the globule of adhesive metered at each nozzle 4' upon the web, as described in our copending U.S. patent application, Ser. No. 537,064, filed Dec. 30, 1974, for Process and Apparatus For Fluid Application. As the sheet web material of wrap paper or the like 3 is thus drawn past nozzle station 4', the successive transverse lines of dots 3" are longitudinally spaced in a controlled manner, which is adjusted to correspond to the regions or locations of the filter sections 1 and 2 where the wrapping of the web material about the filter is to effect securing therebetween, as later described. The synchronization is shown effected by drive box 7', associated with bumper 7, being driven from shaft 8 via 7", and with the metering control drive 6' similarly coupled to shaft 8 by sprocket 6".

The line of filter inserts 1-2 at VII is carried by the web 3, with its adhesive line 3' and spaced transverse dots 3", to a forming die 9 that wraps the web sheet material 3 transversely and with an overlap to provide a closing and adhesive seal along adhesive line 3', with the spaced transverse lines of dots 3" circumferentially securing to predetermined regions of the filter. In accordance with the invention, a transverse cutter blade c.sub.1, is controlled synchronously with this process, as by pulley drives 17-7", to insure transverse cuttting of the filter insert at a region between transverse dots 3", limiting the contact of the blade c.sub.1 with adhesive material to the cut of the line 3', and avoiding adhesive build-up on the cutting edge. The resulting multiple dual filter rods are further cut, as at VIII, and again preferably by a similarly synchronized cutter (not shown), slicing the filter in the space between dots 3". At this point, a wrapped pair of contiguous dual filters F, is provided with the plastic section 2 shown in the center and the charcoal filter 1 sections at the ends. This is abutted against tobbaco sticks 11, and secured with a tipping or other wrap 12, having an inner surface of adhesive 12', but with a central line 12" void of adhesive, all as effected, for example, in said Hauni-Werke machine and bulletin. In accordance with the present invention, this conventional step is followed by a further synchronized transverse cutting by cutter C.sub.2, synchronized by drive 10--10' from shaft 8, again insuring cutting in the space between dots 3" and along the void line 12" to restrict the adhesive contacting the blade to the single line 3', as before.

Symmetrical cigarettes with dual filters are thus provided with a very adherent completely or partly circumferential bond at dots 3" to the desired regions of filter insert section 1 and 2 only, and with minimal adhesive contamination of the cutters. If desired, moreover, the dots 3" may be extended into dashes or a single dash. Suitable hot melt adhesives for the line 3' include, for example, a polyethelene-base with copolymer additives sold by H. B. Fuller of St. Paul, Minnesota, under the type 5134B, or that of Swift Company of Chicago, Illinois, type 625. The hot melt adhesive of the dots or dashes 3" may be tailored to the particular plastic 2 or other characteristics of the filter sections. Suitable pressure-sensitive materials for this purpose include H.B. Fuller type HM 1097 cryton base or synthetic rubber base with copolymer additives; type 1477 of Boler Petroleum Co., Ardmore, Pennsylvania; and type 321 of Union Oil Co., California. The dots 3" may, for example, be from 1/64-1/16 inch in diameter, more or less, spaced longitudinally every 5 mm or so.

Instead of the bumper control illustrated, moreover, other fine control deposition systems may be employed, such as the rotary distributor application described in said U.S. Pat. No. 3,174,689 and the other patents. The technique, moreover, may be applied to other applications than that of cigarette filters where cylindrical or other inserts must be wrapped and the features of the invention are desired; and further modifications will also occur to others skilled in this art--such being considered to fall within the spirit and scope of the invention as defined in the appended claims.