US1969712A

US1969712A - Manufacture of dried wood veneer

Info

Publication number: US1969712A
Application number: US600429A
Authority: US
Inventors: Helffrich Josef
Original assignee: Schutte Lans Holzwerke A G
Current assignee: Schutte Lans Holzwerke A G; SCHUTTE-LANS HOLZWERKE AG
Priority date: 1931-02-20
Filing date: 1932-03-22
Publication date: 1934-08-07
Anticipated expiration: 1951-08-07

Description

Aug. 7, 1934.

J. HELFFRICH MANUFACTURE OF DRIED WOOD VENEER Filed March 22. 1932 each other.

4'0 already according to Patented Aug. A 7, 1934 E NT oFFics 1,969,712 MANUFACTURE OF DRIED WOOD VENEER Rheinau,

Mannheim- Germany, assignor to Schiitte-Lanz Holzwerke A. G., Mannheim-Rheinau, Germany Application March 22, 1932, Serial No.

In Germany February 20, 1931 4 Claims.

This invention relates to a method of producing wood veneer of any width by feeding the wet veneer band formed to a drying device in a direction rectangularly to the course of the 5 fibers.

Dried veneer is, as a rule, produced by means of a drying device comprising a number of pairs of drying plates, the individual drying plates being mechanically movedtowards, and away from,

The platescorrespond in size to that of the veneer sheets to be dried, and as the dimensions of the plates for structural reasons must be kept down, the drying devices in common use can handle only veneer sheets of l5 a limited size. 1

It has further been proposed already to arrange a number of such drying devices one behind the other and' to cause the individual systems to carry out lateral motions in order to convey the veneer sheets'through the various systems from one end of the machine to the other. However, a machine of this kind ,is capable only of'conveying the veneer sheets'in the longitudinal direction of their fibers while the width of the sheets to be dried by the machine is still dependent on the widthof the drying v plates. As is knownto those skilled in the art the length of wood veneer covers the'extension in the direction of the fibers and the width cor- 30. responds to the dimensions measured vertically 'to the direction ofthe fibers. The length thus refers to the length of the log from which the veneer is formed and may amount up to four meters. I

[35. The invention aims 'atiproducing wood veneer of any width by passing the veneer band, in contrast with the veneer sheet, through the drying device transversely to the direction of fibers.

Methods of drying which drying is effected by means of a plurality of superposed heating rollers about which the veneer has to be guided. As long as the veneer is wet it can be conveniently placed around a roller, but as soon as it 46 begins to dry it becomes brittleand forms cracks when so applied. It'has been tried to protect thin veneer against splitting by passing thin layers of paper through the rollers together with the veneer to 50' has been found that paper strips-glued to. dried veneer cannot prevent or cracking, not to mention the cost involved in applying and removing the paper. It is impossible, accor to practical testsmade, to dry, for instance, in this manner a veneer havveneer bands are known glue them on to the latter, but it breaking and splitting ing a thickness of 3 millimeters without exposing it to fracture or splitting in the drying device. I

Accbrding to the invention, these drawbacks are overcome by drying the veneer hand between two plane heating plates of known type which are moved towards and away from each other and between which the veneer is passed transversely to its direction of fibers. This method permits a simple and clearly arranged construction of the drying device which .iseasy to operate. Furthermore, if the conveying rolls for passing the'veneer through the heating plates as well as the cutting device are disposed in the plane of theheating plates, the veneer band can be fed to the cutting device without curvatures or bends and behind the drying device a cooling path or bed may be provided on which the dried, hot -veneer band canbe cooled off so as to permit its piling or further use immediately after cutting.

One form of apparatus which, according to the invention, can be used {or carrying out the method is illustrated in the accompanying drawmg.

Referring to the drawing, A is a roll on which the veneer coming off from a log is wound. The roll A may of course be dispensed with and the veneer taken directly from the peeling ma.- chine. B is the veneer which is passed between the two heating plates C, C heated by steam, hot air or electricity. Comparedwith the plates used in the ordinary drying devices, the heating plates C,'C"are quite long, up to 5 meters or over, because the longer the plates, the more quickly the veneer can be passed between them. In the known types of driers of this class employing always a large number of superposed heating plates the latter have a maximum length not exceeding ,3 meters.

As described in detail below, the heating plate C is intermittently raised and lowered so as to press the wet veneer, the raising of the plate permitting the vapors developed to escape. Behind the plates C, C' a cooling bed D is provided consisting, in the embodiment shown, oi a grate, though it might be constructed in the form of a cooled plate or the like and be equally eflicient. On the cooling bed I) the hot veneer is cooled down to such a degree that it can be touched by hand; While the veneer lies. on the cooling bed, defective parts may be marked for subsequent removal by the cutting device F.

' E are conveying rollers actuated by hand or machine and penetrating the grate or cooling bed D. The top roll E is provided with a hand wheel, in the embodiment shown, which can be turned by the operator according to the degree of drying effected which can be ascertained by observing whether or not steam is developed in a visible manner at the end of the plates C, The nature of the conveying device forms no part of the invention. F is a cutting device comprising the lower companion blade and an upper cutter block which can be moved up and down by hand. H is the delivery table whose length may be adapted to the width of the veneer desired.

By ineansof the crank P driven in any'suitable manner the draw bar G'is reciprocated and, by means of an interposed braking cylinder Q, acts on the piston rod R of the latter which is articulated to the lever S disposed at T on the ,frame of the machine and engaging with the rod X the lever K rotatably'arranged at V on the machine frame. A draw bar G connects the four levers K shown which are thus moved to and fro on, the rotation of the crank P. To the other arm of the levers k are articulated the members I at W and secured with their upper ends to the plate C which is thus raised andlowered when the crank P is turned, the contact between the plate C and the veneer being timed and controlled by the adjustment of the braking cylinder Q. I

One of the essential features of the method is that the veneer is continuously passed between the plates C according to the degree of drying ascertained by observation.

L indicatesthe lower frame portion, M are transverse braces, N are vertical supports and 0 is the upper frame portion.

The device functions as follows:

The veneer band B coming from a roll or directly from the peeling machine is passed between the heating plates C, C by hand or by means of suitable devices, not shown, when the plates are in opened position, and drawn between the rolls E which do the further feeding of the veneer B. gradually according to the opening and closing of the plates. The rolls E are, as shown, driven by hand, or, not shown, mechanically, i. e. by the member G, and-their speed is regulated so that the portion of the band B coming out of the drier has attained the desired degree of dryness. The band B then passes on tothe coolerD andthe cutterl k- Theveneer sheetscanbepiledanduseddirectlyafterbcing cut.

I claim: 1. A device for producing dried veneer, cunprising a peeling device separating an endless band of wood transversely to the course at its fibers from a trunk, intermittently moved transporting means for carrying the hand away, heatable plates on both sides of said band, driv- I ing means for moving saidheatable plates so as to cause said plates to press the band when stationary between them for a predetermined time, and cutting means for separating the band into individual dried veneer plates. N

2. A device for producing driedveneer, comprising means for introducing an endless hand of wood transversely to the course of its fibers, intermittently moved transporting means for carrying the band away, heatable plates on both sides of the band, driving means for moving said heatable plates so as to cause said plates to press the band when stationary between them tor a predetermined time, and cutting meansdor separating the band into individual dried veneer 1U plates. 3. A device for producing dried. veneer, comprising means for introducing an endless band of wood transversely to the course of its fibers, intermittently moved transporting means for con-- veying the band, heatable plates disposed on both sides of the band of wood and actlm as ventilating drier therefor, means for moving said heatable plates so as to came said plates to press the band when stationary between them for a predetermined'time, and cutting means for separating the band into. individual dried plates.

4. A device for producing dried veneer, eanprising means for introducing an band oi. wood transversely to the course of its fibers, intermittently moved transporting means for con-' veying the band, heatable plates on both sides of the band, said' plates being plane and disposed partly above and below the band to be m dried, driving means for moving said heritable plates so as to cause said plates to press the hand when stationary between them for a predetermined time, and cutting means'for separating the band into individual dried veneer sheets.

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