Patent GB-1070670-A (GB)
Title: Improvements in or relating to the manufacture of plywood
IPC: B27D1/04
Filed: 1965-12-09
Abstract: 1,070,670. Woodworking. POTLASH FORESTS Inc. Dec. 9, 1965 [Jan. 21, 1965], No. 52249/65. Heading B5L. [Also in Division B3] A method of manufacturing plywood comprises joining a series of pieces of wood veneers end-to-end by tapering the end edges thereof and overlapping the tapered ends with adhesive therebetween to provide a first - continuous strip of veneer, covering the continuous strip with cross band veneer pieces with adhesive between the strip and pieces while advancing the continuous strip lengthwise, forming a second continuous strip of veneer in substantially the same manner that the first continuous strip is formed, laying the second continuous strip upon the cross band veneer strip with adhesive therebetween, cutting the composite continuous strip thus formed into sections of desired length, and pressing the sections. In apparatus for carrying out the method, the pieces of veneer for forming the first-continuous strip 25, 26 are initially in a stack 10 and fed successively by a carrier 11 having a vacuum cup 12 along a conveyer 13 and into engagement with a stop 14. Each veneer is then fed by a conveyer 15 between cutters 16, which may comprise saws or endless abrasive bands and form tapering surfaces along the ends of the veneers, one surface being above and the other below the veneers. The upper surface is coated with adhesive from a device 17 and the finished veneers 24 are then transferred by an operator 18 to a conveyer 20 with the tapered surfaces of adjacent veneers 25, 26 engaged to form scarf joints which may be further joined by stapling or stitching. The cross band veneers are initially in a stack 27 and are fed by an operator 28 between glue spreading rollers 30 and are then placed to abut one another on the first strip by an operator 32, the cross band strips being shown at 33. The pieces of veneer for the second and upper continuous strip are initially in a stack 34 and are treated in the same manner as the pieces 10 to form the second strip, being laid on the cross band pieces by an operator 43. The assembled strip is then cut into desired lengths by a saw 50, the lengths forming a stack 51 in a device 52 for transfer along a conveyer 54 to a pressing and curing device. In another embodiment, the operators 18 and 43 are replaced by automotive transfer mechanisms. Sawing.-The transfer conveyer 13 consists of rollers (60, Figs. 3 and 4) which are rotated by chain drives (62) to move a veneer into engagement with the stop (14), the veneer being pressed against the first-roller by pressure wheels (63) acted upon by a cylinder assembly (65). The veneer is then moved by an element (66) reciprocated by a cylinder assembly (67) along the cross conveyer (15) consisting of opposed pairs of upper and lower belts (68) driven by a chain drive (71). During its passage between the belts, the upper surface at one end and the lower surface at the other end are tapered by saws (72) driven by motors (73), glue then being applied to the upper tapered surface by the device (17). In another embodiment, the tapered surfaces are formed by belt sanders (81, 82, Fig. 7) as the veneer is fed therebetween by rollers (77, 78).