IMPROVEMENTS IN CORRUGATING MACHINES

Abstract: A machine for making corrugated board comprising means to feed two separate webs (W1; W2) between two respective pairs of corrugating rolls (1, 2; 3, 4) to form two corrugated layers, a first adhesive applicator (5) for applying adhesive to the peaks of at least one of the two corrugated layers, means (2; 3) to bring the two corrugated layers together at the peaks of the corrugations, means (8) to convey the joined corrugated layers past a second adhesive applicator (12) for applying adhesive to the exposed peaks of one of the corrugated layers, and means (22) to apply a liner web (W3) to the corrugated layer having the adhesive on its peaks, and including means (21) for pneumatically urging the corrugated layers into contact with the second adhesive applicator as the joined layers move past the second adhesive applying means.

Description: Improvements in Corrugating Machines This invention concerns improvements in or relating to machines for making corrugated board, and in particular to the machines described and illustrated in Australian patent applications Nos. 62323/86 and 2271/85, in the name of AMCOR Limited, to which reference is directed in their entirety- According to one aspect of the present invention there is provided a machine for making corrugated board comprising means to feed two separate webs between two respective pairs of corrugating rolls to form two corrugated layers, a first adhesive applicator for applying adhesive to the peaks of at least one of the two corrugated layers, means to bring the two corrugated layers together at the peaks of the corrugation ' s, means to convey the joined corrugated layers past a second adhesive applicator for applying adhesive to the exposed peaks of one of the corrugated 1 ayers, and means to apply a liner, web to the corrugated layer having the adhesive on its peaks, and including means for pneumatically urging the corrugated 1 ayers into contact with the second adhesive applicator as the joined layers move past the second adhesive applying means. , ■ In a preferred construction, the joined corrugated layers are conveyed by a roll along a path which, in the absence of pneumatic pressure, would result in the exposed peaks of the corrugated layer being spaced from the second adhesive applicator, the joined corrugated layers being urged pneumatically away from the roll by air pressure applied from within the roll so as to engage the adhesive applicator. This ensures uniform contact of the peaks of the corrugated layer with the adhesive applicator, which is preferably in the form of a roll coated with a thin layer of adhesive. Other aspects of this invention, each useful in its own right and described in detail below, are concerned with the use of air pressure to lift one corrugated layer from its corrugating roll and into contact with the other corrugated layer, a construction of the second adhesive applicator including a weir over which a controlled flow of adhesive is arranged to pass into a gap between a fixed member and a moving roll arranged to convey adhesive from the gap and to apply it to the corrugated medium (preferably any excess is removed by a doctor roll or other doctoring device), and the mounting of heaters and of the second adhesive applicator on one or more subsidiary frames separate from the main frame, preferably with means for moving these subsidiary frame or frames automatically away from the roll carrying the joined corrugated layers when the machine stops. The invention will now be described, by way of example only, with reference to the accompanying drawings in which; Figure 1 is a diagrammatic side view of a machine for making corrugated board; and Figure 2 is an enlarged detail of part of the machine of Figure 1. The machine shown in the drawings is s i mi 1 ar to that shown in Figure 3 of Australian patent application 2271/85 referred to above. Referring to Figure'lj a web WI is corrugated in known manner between fluted corrugating rolls 1 and 2, and a web W2 is similarly corrugated between similar rolls 3 and 4. Adhesive is applied to the peaks of the corrugations by an applicator roll 5 and the corrugated webs WI, W2 are brought together between the rolls 2 and 3. The webs W1,W2 are held to their respective rolls 2,3 by suction applied through chambers 6 and 7 respectively. The joined layers are then carried on the roll 3 towards a fluted carrier roll 8. As the • adhesive at this stage is not yet tacky, the transfer to the roll 3 of the corrugated layer on roll 2 is assisted by air flow radially from a pressure chamber 9 in the roll 2. After arrival on the roll 8.» the joined corrugated layers are held on the fluted periphery of the roll 8 by suction applied through a chamber 10. The transfer from roll 3 to roll 8 is assisted by pressure air applied through a chamber 11 in the roll 3. As the joined layers are conveyed in a clockwise direction by the roll 8, adhesive is applied to the exposed (outwardly facing) peaks of the corrugated layer W2 by an adhesive applicator unit 12.. Referring now also to Figure 2, the unit 12 comprises an applicator roll 13 which is positioned so that there is a small gap between its periphery and the peaks to which adhesive is to be applied. A container, in the form of a " square tube 14, extends across the machine and has a hole 15 in its upper wall. A plate 16 is fixed to the tube so that its top edge 16A is higher than the top of the tube, and a small gap is formed between it and the roll 13. A further plate 17 is al.so fixed to the tube 14, oppo.site the plate 16, so that its upper edge is higher. than that of the plate 16. Thus the edge 16A of the plate 16 forms a weir, so that the amount of adhesive flowing over it and into contact with the roll 13 is substantially constant. Adhesive is fed from a tank (not shown) along a pipe 18 into the tube 14 and out through the hole 15, so that it flows over the plate 16 and onto the roll 13. Excess adhesive flows over the plate 17 and returns to the tank. The amount of adhesive carried on the roll 13 is metered by a roller 19 which, in turn, is cleaned by a doctor blade 20, and the adhesive is returned to the tank. As the roll 13 rotates with the correct amount of adhesive thereon, the joined layers being conveyed by the roll 8 pass a pressure chamber 21 in the roll 8 from which air flows through ' sui tabl e radial passages so as to urge the joined layers outwards towards the roll 13. This causes contact with the roll 13 and adhesive to be applied to the peaks. A liner W3 is fed around a roller 22 and applied to the adhesive-coated peaks of the outer corrugated layer formed by the web W2. Bonding of the liner to the peaks is assisted by heaters 23 and 24. The joined corrugated layers and the attached liner are then removed from the roll 8 by pressure air fr.om chamber 25 and are fed over a plate 26 towards further processing machinery which forms no part of the present invention. Pressure air is applied at chambers 27 and 28 provided in rolls 2 and 3 respectively so as to keep the suction holes in those rolls clear of any debris. The adhesive unit 12 is carried by a frame 29 which can move along a plate 30 on wheels 31. The frame has a toothed rack 32 fixed to it which is engaged by a pinion 33 driven by a motor 34. The heaters 23 and 24 are carried by a frame 35 having wheels 36 which run on a plate 37. A toothed rack 38, fixed to the frame 35» is engaged by a pinion 39 driven by a motor 40. The corrugating rolls and roll 8 are driven from a separate motor 41. The motors 34, 40 and 41 are connected to a central control unit 42, of a suitable known form, so that when the machine is stopped, the motors 34 and 40 are energised to rotate the respective pinions 33 and 39 and thus cause the adhesive unit 12 and the heaters 23 and 24 to be moved away from their respective operative positions. A manual override is also provided so that the various units may be moved as and when the operator wishes.

Claims: Claims 1. A machine for making corrugated board comprising means to feed two separate webs (W1;W2) between two respective pairs of corrugating rolls (1,2; 3,4) to form two corrugated layers, a first adhesive applicator (5) for applying adhesive to the peaks of at least one of the two corrugated layers* means (2;3) to bring the two corrugated layers together at the peaks of the corrugations, means (8) to convey the joined corrugated layers past a second adhesive applicator (12) for applying adhesive to the exposed peaks of one of the corrugated layers, and means (22) to apply a liner web (W3) to the corrugated 1 ayer having the adhesi e on its peaks, and including means (21) for pneumatically urging the corrugated layers into contact with the second adhesive applicator as the joined layers move past the second adhesive applying means. 2. , A machine according to claim 1 in which the joined corrugated layers are arranged to be conveyed past the second adhesive applicator (12) by a roll (8) including a pressure chamber (21) from which air pressure acts to urge the corrugated layers onto the adhesive appl icator. 3. A machine according to claim 2 in which the second adhesive applicator (12) comprises a roll (13) and a fixed member (16) mounted close to the roll and serving as a weir over which adhesive is arranged to pass into a space between the roll and the fixed member so as to coat the roll with a layer of adhesive of substantially constant thickness-. 4. A machine according to any one of claims 1 to 3 in which one of the corrugated webs (WI) carried by a first corrugating roll (2) is arranged to be transferred to the corrugating web (W2) carried by a second one (3) of the rolls, the first roll (2) including a pressure chamber (9) from which air pressure acts to assist the transfer of the corresponding web (WI) on to the other web (W2)_; 5. A machine according to claim 4 in which the second-mentioned roll (3) includes a pressure chamber (11) from which air pressure acts to assist the transfer of the joined corrugated webs onto a further roll (8) arranged to carry the joined webs towards the second adhesive applicator (13). 6. A machine accordi ng to an oneof claims 1 to 5, includingone or more heaters (23,25) adjacent to the means (8) for carrying the joined corrugated webs (WljW2) and the applied liner web (W3) for promoting the bonding of the liner web (W3). 7. A machine accordi ng to claim 6 in which the heater or heaters (23,25) and the second adhesive applicator (12) are mounted on one or more subsidiary frames separate from the main frame of the machine, and including means (33,39) for moving the subsidiary frame or frames automatically away from the roll or other * means (8) arranged to carry the joined corrugated webs past the second adhesive applicator.

Inventors: STUTT COLIN, STUTT, COLIN
Applicants: LANGSTON MACHINE, THE LANGSTON MACHINE COMPANY LIMITED
Application year: 1989
Main classification: B31F1
IPC codes: B31F1