Improvements in the method of and apparatus for making plywood

摘要

In the formation of plywood, adhesive particles in a dry or moist condition are distributed uniformly on plies carried by a conveyer beneath a vibrating sieve which forms a shower of particles. A plasticizing liquid, such as water, is simultaneously or subsequently applied, the assembled plies being afterwards bonded together by pressure. Plies 21, Fig. 4, from a pile 22 are placed on a conveyer 20 and are carried beneath a box-like distributer 24, having a perforated base and containing dry adhesive, which is reciprocated by an eccentric driven by belt gearing from the conveyer shaft. Adjustment of the amount of adhesive fed may be effected by a coned pulley drive for the eccentric. Moistening of the adhesive is effected by a sprayer 31 consisting of a pipe 36, Fig. 5, supplying a current of air and extending across the width of the plies, water being supplied by a perforated valved pipe 33 mounted in the pipe 36. The spraying may take place after the scattering of the adhesive or simultaneously therewith by directing the spray into the falling stream of adhesive. In assembling three-ply veneer, three piles of plies 22, 26, 30 are provided and two adhesive distributers 24, 28 and moistening devices 31, 32. To avoid the deposition of adhesive on the conveyer, the continuous conveyer 20 is replaced by a series of conveyers 53, 54, 66, Fig. 13, the adhesive distributers 52, 67 being situated over the spaces therebetween. Screens 58, 59 are provided on each side of the distributers and sprayers 75 inject moisture through gaps therein, air being supplied by a common trunk 78 and water by pipes 75; adhesive is supplied to the distributers by hoppers 70, 71. In a modified arrangement, two separate conveyers may be arranged in parallel, a ply being supplied with adhesive on each one and subsequently superposed, after which the third ply is placed n position. Where the wood of the core ply is different from that of the back and front plies, adhesive is supplied only to the core ply.