DEVICE FOR SPREADING JOINTING ADHESIVE ON PAPER SURFACE

Abstract: The device comprises a number of rolls fitted with adhesive nozzles (20), said rolls being arrayed for the fabrication of multi-layer paper sacks in a manner that a plurality of axially long spreading rolls (E), with an axially extending array of nozzles on the periphery thereof, are arranged parallel and adjacent to each other for making transverse joints on paper webs that provide the various layers, that next on the line is an axially short sizing roll (C) whose periphery is provided with a circumferential array of adhesive nozzles to produce a lengthwise joint for tube making, that downstream of the folding station of bottom shut-off flaps there are provided one or more sizing rolls (A, A1) for bottom shut-off flaps, and that last on the line is a roll (D) to produce adhesive joints for gluing a bottom flap.

Description: Device for spreading jointing adhesive on paper surf ce. The present invention relates to a device for spread¬ ing jointing adhesive on a paper surface, said device comprising a rotatable adhesive spreading roll, norm¬ ally closed nozzles on the periphery of said spread¬ ing roll, said nozzles being connected via closed adhesive supply passages to an adhesive supply means and the shut-off means of said nozzles being adapted to open by the action of an external pressure while the spreading roll is rotating. A device of this type is disclosed in FI Patent public¬ ation 49779. It proposes the use of one or more para- lel adhesive spreading rolls for applying glue seams or joints e.g. to the surface of a cardboard web, whereafter such cardboard web can be obviously used e.g. for fabrication of packaging boxes. The prior art jointing adhesive spreading devices used for the fabrication of multi-layer paper sacks employ open adhesive troughs or gutters from which the adhesive is transferred. through scraper-equipped arrays of rolls onto an actaul adhesive spreading roll. Such assembly involves, however, several drawbacks. In open adhesive gutters, the adhesive sets and toxic solvents evapor¬ ate to environment. Production rate is limited since the increase of speed leads to more splashing of glue. Also the repeated need for washing lowers efficiency. Scrapers that are worn out or out of order let through lumps of glue leading to improper joints and increased adhesive consumption. An object of the invention is to provide a novel O PI device capable of eliminating all the above drawbacks involved in the fabrication of multi-layer sacks. This object is achieved on the basis of the inventive characterizing features set forth in the annexed claims. One exemplary embodiment of the invention will now be described in more detail with reference made to the accompanying drawings, in which fig. 1 is a perspective view of one embodiment of an adhesive spreading roll used in a device of the invention. Fig. 2 shows in axial section an adhesive spreading roll provided with appropriate adhesive supply means. Fig. 3 is a larger scale sectional view along line III-II in fig. 2 showing the design of one embodiment of an adhesive supply nozzle. Fig. 4 is a diagrammatic view of a device of the invention in which the adhesive supply - rolls are employed in a novel manner to provide an automatic paper sack production line. Referring first to figs. 1 and 2, the design of an adhesive supply roll will be explained. A roll 10 is mounted on a shaf 11 which is rotated by a drive motor 12 through a gear 13. Mounted on shaft 11 is an adhesive dispensing chamber 14 which on the sides and on the inner rim is confined by a core member 5 rotating along with shaft 11. On the outer rim side, chamber 14 is confined by a fixed cylinder jacket 17 packed with seals 16 relative to core member 15. The adhesive is driven by the application of pressure through a hose 18 passed through rim jacket 17. Provided on the periphery of roll 10 are arrays of nozzles 20 and 21 on the spots aligned with desired adhesive joints. In the present case, the partially circling array of nozzles 20 is located adjacent the edge of roll 10 and associated with the ends of this array are one or more axially extending arrays of nozzles 21. Nozzles 20, 21 are each individually connected by means of hoses 29 to adhesive dispensing chamber 14. The nozzle assembly shown in fig. 3 comprises a tubul¬ ar body member 21 which is secured to a roll jacket hole by means of locking nuts 29 and 30. Threaded on the outer end of body 21 is a nozzle cap 22 whose orifice is closed by a shut-off means 23 through the pressure of a spring 24. A rod 25 associated with shut-off means 23 urges another shut-off means 26 against the action of a spring 28 so as' to keep shut- off means 26 off a seat surface 27 permitting the passage of adhesive. Shut-off means 26 along with its spring 28 is fitted in a mounting sleeve 31 secured with threads 32 inside said body 21. The top end of sleeve 31 is provided with slots 33 for allowing the passage of adhesive. As roll 10 rolls on a surface to be glued, said surf¬ ace presses shut-off means 23 temporarily inwards with OMPI a consequence that adhesive is extruding out of the nozzle slot. The amount of adhesive coming out of the nozzle depends on the rotational speed of roll 10, viscosity of the adhesive and the supply pressure applied. The amount of adhesive can be controlled by controlling the supply pressure. When nozzle cap 22 is loosened, said second shut-off means 26 moves against seat surface 27 shutting off the passage of adhesive. This way it is possible to make any nozzle inactive as well as to reactivate it. Thus, the same roll can be provided with a sufficient number of nozzle arrays by means of which the posit- ionas and lengths of adhesive joints can be adjusted by only activating the desired arrays of nozzles. Thus, the machine can be readily readjusted to make it suitable for the fabrication of e.g. sacks of various sizes. For example, the roll shown in fig. 1 is intended for producing a patterned adhesive joint for a sealing flap ' made in the bottom of a sack by folding. The width of a bottom can be varied by deciding to use either one of the axial arrays 21. The bottom end of said nozzle body 21 is provided with a plastic flexible connecting hose 19 whose other end communicates with adhesive dispensing chamber 14. The application of a jointing adhesive spreading roll of the invention is depicted in fig. 4. The figure shows diagrammatically an assembly for the fabricat¬ ion of multi-layer paper sacks or bags. At the outset of a production line there are a plurality of axially long rolls E placed on top of each other. Rolls E are provided with axially extending arrays of nozzles for making transverse joints or seams in the super- imposed paper webs that make up the various layers of a paper sack. Next comes an axially short sizing or gluing roll C around whose periphery extends an array of adhesive nozzles for producing a lengthwise joint in view of making a hose. The present case deals with the fabrication of sacks sealable at both ends, the filling end of a sack being fitted with a tubular filling valve. In the fabricat¬ ion of such sacks, a hose or tube is cut into lengths in a manner that the filling ends of two successive sack blanks are at any given moment abutting and at the next position the bottoms are abutting. In order to avoid the necessity of turning a tube blank, such blanks are passed onto two parallel bottom fabricat¬ ing lines. Each bottom fabricating line is provided with two pairs of rolls A, A., and A, A., on the same axial line. The sealable sack bottoms are folded in a per se known manner and pass each under its own pair of rolls A, A- . Thus, roll A produces a patterned joint (see fig. 1) and roll A., produces a straight bottom joint. On the filling end side of a sack, a roll B applies an adhesive joint for fastening a fill¬ ing valve tube. Rolls D make adhesive joints at each end of a sack for gluing a bottom flap. If the question is about sacks to be sealed only on the bottom side, the lower array of rolls A, A ; B; D will be left out of each bottom fabricating line. The adhesive is supplied from a pump not shown to a manually operated shut-off valve 1 , through a manually operated pressure reducer 5 and an electric adhesive volume controller 4 and further through an electric three-way valve 3 to an adhesive lead-in 2 which is * 2.EJ PI set up as described in connection with figs. 1 and 2. When operating a device of the invention, the adhesive is continuously in a closed space. Setting of the adhesive cannot occur, nor can toxic solvents evaporate to the environment. The way an adhesive is supplied or fed does not limit the rate of production. In order to speed up drying of adhesive joints and, hence, to further increase the rate of production, it is plaus¬ ible to employ a preheated adhesive. Adhesive con¬ sumption is low since the adhesive can be accurately metered in proper positions.

Claims: Claims 1. A device for spreading jointing adhesive on a paper surface , said device comprising a rotatable adhesive spreading roll (10), normalle closed nozzles (20) on the periphery of spreading roll (10), said nozzles being connected by closed adhesive supply passages (19, 14, 18) to an adhesive supply means and the shut-off means (23) of said nozzles being adapted to open by the action of an external pressure while the spreading roll is rotating, c h a r a c t e r i z e d in that the device is used for the fabrication of multi-layer sacks in a manner that a plurality of axially long spreading rolls (E) , with an axially extending array of nozzles provided on the periphery thereof, are posioned parallel and adjacent to each other for producing transverse joints on paper webs which make up the various layers, that following next on the line is an axially short sizing roll (C) whose periphery is provided with a circumferential array of adhesive nozzles to provide a lengthwise joint for making a tube, that following after the folding station of bottom shut-off flaps are one or more sizing rolls (A, A- ) of bottom shut- off flaps, and that the last item is a roll (D) to produce adhesive joints for gluing said bottom flap. 2. A device as set forth in claim 1 , c h a r a c t e r i z e d in that provided on the same axial line is at least one pair of bottom shut- off flap sizing rolls (A, A 1 ) whose arrays of adhesive nozzles are positioned in a manner that one (A) pro¬ duces a patterned joint and the other (A..) produces a straight joint. 3. A device as set forth in claim 2, c h a r a c t e r i z e d in that the station for sizing the bottom shut-off flaps comprises two pairs of rolls (A, A 1 ; A, A 1 ) , one pair for each end of a sack, and that provided between one of the pairs of rolls (A, A 1 ) and the bottom flap sizing roll (D) is a shut-off valve sizing roll (B) . 4. A device as set forth in claim 3, c h a r a c t e r i z e d in that for sizing the bottom shut-off flaps there are provided two parallel production lines. 5. A device as set forth in claim 1 or 2, c h a r a c t e r i z e d in that the periphery of said axially short roll (C) , bottom flap sizing rolls (A, A 1 ) as well as said bottom flap sizing roll (D) is provided with an array of adhesive nozzles extend¬ ing partially or completely therearound. 6. A device as set forth in claim 5, c h a r a c t e r i z e d in that at least some of the bottom sizing rolls (A, A 1 , D) comprise an array of adhesive nozzles at the rim edge of a roll and connected to this array are one or more axially extending arrays of nozzles (21). 7. A device as set forth in any of the claims 1-6 Λ c h a r a c t e r i z e d in that for controlling the positions and lengths of adhesive joints by removing or adding nozzles (20) from or to nozzle seats (21) available on the periphery of a roll, said nozzles (20, 22, 23) are removable from their seats (21) which are fitted with a shut-off means (26) for keeping the adhesive passage sealed when nozzle (22, 23) is removed. 8. A device as set forth in claim 1, c h a r a c t e r i z e d in that each spreading roll (10) is associated with an adhesive dispensing chamber (14) whose outer periphery is defined by a fixed rim jacket (17) and inner periphery is defined by a core member (15) rotating along with a roll shaft (11), and that said rim jacket (17) is associat¬ ed with an adhesive supply tube (18) and said adhesive dispensing chamber (14) is connected to each nozzle- (20) by means of individual tubes or hoses (19) connected to said core member (15) .

Inventors: KUTVONEN MARTTI, SANDGREN LASSE, KUTVONEN, MARTTI, SANDGREN, LASSE
Applicants: KUTVONEN MARTTI, SANDGREN LASSE, KUTVONEN, MARTTI, SANDGREN, LASSE
Application year: 1984
Main classification: B05C1
IPC codes: B05C1, B05C5, B31B19