Patent GB-950817-A (GB)
Title: Improvements in methods and apparatus for patching veneer to plug a hole or holes therein
Inventor: CLAPP CHARLES CYRUS
IPC: B27G1/00
Filed: 1962-10-16
Abstract: 950,817. Woodworking; laminates and laminating. WEYERHAEUSER CO. Oct. 16, 1962, No. 39155/62. Headings B5L and B5N. [Also in Division B8] A method of patching veneer to plug a hole or holes therein comprises filling the hole or holes with particulate thermoactive material with the upper face of the veneer including the area .of the hole or holes in contact with an external backing surface, superficially heating and activating the material at the lower face of the veneer to effect at least partial solidification at the lower face and to a limited depth terminating short of the upper face in contact with the surface, terminating contact of the veneer with the external backing surface, and heating the material in the hole or holes to activate the material which was in contact with the backing surface, whereby a substantially solid plug is formed in the or each hole. In apparatus for carrying out the method, the veneer to be patched, which is in the form of strips V, is fed from a feed conveyer into a crowder conveyer 10 which underlies the receiving end of a suction screen or patching conveyer 12 running at a slightly slower speed than the conveyer 10 so that the veneer strips are moved into abutting relationship. The patching conveyer 12 consists of a wire mesh screen belt and disposed above the lower run thereof is a suction box 14 having a number of holes 14a by which a suction source connected to a tube 14b holds the veneers against the screen of the patching conveyer. The stripes are carried by the patching conveyer 12 above an applicator 18 which has a unit rotatable by a shaft 66 for flinging particulate thermoactive material upwards to the veneer strip. Where a strip has a hole to be filled, the material enters the hole and is retained in the hole and against the screen of the patching conveyer 12 by the suction in the box. As the strips pass from the applicator, a scraper 18a removes excess material before the strips pass over a heater unit 20 having elements 20b which heat the thermoactive material to effect solidification at the lower face to a depth terminating short of the upper face in contact with the screen of the conveyer 12. After leaving the heater unit and the area affected by the suction box, the strips, with the patches at least partially solidified, are carried on to a bottom surfacing sheet 16a of paper which is coated with adhesive from a trough 9 by rollers 7, 8 and slides on a platen 22 before passing between compression rolls 26, at least the upper one of which is heated to activate at least the upper surface of the thermoactive material in the holes. An upper surfacing sheet of paper may be applied to the upper surface of strips, adhesive being applied to the paper from a trough 9a by rollers 7a, 8a. Prior to contacting the upper surfacing sheet, thermoactivation of the upper surface of the material may be effected by infra-red lights 25. Any material which may adhere to the screen is removed by a brush 82 and jets 84 and extracted by a suction hood 80. The thermoactive material preferably comprises a thermoplastic substance, such as a mixture of resin and extender, or beads of expandable polystyrene, and may include sand or coffee grounds.