Patent EA-000656-B1 (EA)
Title: Core of corrugated cardboard, method and for its manufacture
Inventor: UZELI ALFRED FREDY
IPC: E04B1/12
Filed: 1997-07-24
Abstract: 1. A method of manufacturing a core (22) of corrugated cardboard/ comprising the steps of superimposing a multiplicity of layers of corrugated cardboard/ cutting the layers perpendicular to a longitudinal direction of the corrugations of the corrugated cardboard, coating the layers throughout with a liquid hardenable coating material (48) containing water glass and hardening the coating material (48). 2. The method of Claim 1, wherein the step of coating the layers is performed in a corrugated cardboard manufacturing machine (80). 3. The method of Claim 1, wherein the step of cutting the layers into strips (20) of a width (b) according to the thickness of the core (22) is performed prior to the step of superimposing the multiplicity of layers. 4. The method of Claim 3, wherein stacks (38) of the strips are formed and laid flat with the longitudinal direction of the corrugations being substantially vertical, wherein -the liquid coating material (48) is applied on an upper surface (39) of each stack (38), wherein the coating material (48) is blown through the corrugations by an air stream, and wherein surplus coating material exiting from the lower surface of the stack is collected. 5. A core of corrugated cardboard with two parallel face surfaces (39), comprising a multiplicity of layers of corrugated cardboard, the longitudinal direction of the corrugations of the corrugated cardboard being perpendicular to the face surfaces (39), the core (22) being coated throughout with a hardened coating material (48) containing water glass. 6. A sandwich board comprising a core (22) according to Claim 5 and a covering board (25, 28, 58) on at least one of the face surfaces (39) of the core and bonded to the core. 7. The sandwich board (26) of Claim 7, comprising a plurality of superimposed cores (22) and a covering board (25, 15 29, 58) on each of the face surfaces of all cores. 8. The sandwich board of Claim 7, comprising three cores (22) and four covering boards (25, 29, 58), the board being rectangular, the middle core (22) being recessed with 20 respect to the covering boards (25, 29, 58) on two opposite sides and the two outer cores (22) being recessed with respect to the covering boards (25, 29, 58) on the two other opposite sides. 9. An apparatus for performing the method of Claim 1 comprising: - a stacking means (36, 96) for superimposing a multiplicity of corrugated cardboard layers a cutting means (14, 91) for cutting the layers perpendicular to the longitudinal direction of the corrugations into strips (20) with a width (b) according to the thickness of the core (22) to be manufactured, - a coating means (46, 85, 86) to coat the layers throughout with a liquid hardenable coating material (48) containing water glass and - hardening means (62) for hardening the coating material. 10. The apparatus of Claim 9 wherein the cutting means (14, 91) is arranged upstream of the stacking means (36 96). 11. The apparatus of Claim 9 wherein the coating means (85, 86) is arranged in a cardboard manufacturing machine (80) and comprises a coating device (87, 88) for each of the paper 10 webs (82/ 84) of which the corrugated cardboard (94) is composed. 12. The apparatus of Claim 11 wherein the coating devices (87, 88) are arranged such that they coat each paper web (82, 84) on both sides over their entire surface. 13. The apparatus of Claim 9 wherein the stacking means (118) is a winder, which winds the layers into a roll 121). 14. The apparatus of Claim 9 wherein the coating means (46) comprises a conveying means (42) for transporting a stack (38) of superimposed strips (20) of corrugated cardboard, the longitudinal direction of the corrugations being substantially vertical, the coating means comprising at least one nozzle (46) above the conveying means (42) to apply a screen of the coating material (48) on an upper surface (39) of the stack (38), a blowing means (46a) to blow the coating material through the corrugations/ and a collecting means (56) for collecting surplus coating material exiting from the lower surface of the stack (38). 15. Use of the sandwich board according to Claim 6 for the construction of buildings.