US2436653A - Device for determining slope of grain in wood veneers - Google Patents

Description

Feb. 24, 1948. .1. P. LIMBACH ET A1. O 2,4%;@53

DEVICE FOR DETERMINING SLOPE OF GRAIN IN WOOD VE-NEERSv Filed June 21, 1946 @www Patented Feb. 24, 1948 DEVICE FOR DETERMINING SLOPE OF GRAIN IN VENEERSr John P. Limbach and Benson H. Paul, Madison, Wis., dedicated to the free use of the People in the territory of the United States Application June 21, 1946, Serial No. 678,187 2 claims. (C1. :a3-1) (Granted under the act of March 3v, 1883, as amended April 30, 1928; 370 0. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30. 1928, and the invention herein described, if patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon. Y

We hereby dedicate the invention herein described to the free use of the People in the territory of the United States to take eiect on the granting of a patent to us.

This invention relates tomeasuring instruments having as their purposethe measuring of the slopes of Wood grains in sheets of wood veneers.

In grading and inspecting wood veneers, a determination of the slopes of the grains is an important factor. It is known in the art that an excessive slope of grain in a wood veneer reduces the strength of the veneer and makes it more liable to Warp with a change in its moisture content. A purpose of this invention is to provide an instrument of simple and light construction capable of rapidly and conveniently determining the degree of slope present through the thickness of a sheet of wood veneer.

For a detailed description of our invention, reference is made to the accompanying drawings in which Figure 1 is a three-dimensional view of the invention and Figure 2 is a vertical section of a part of the device on the line 2-2 of Figure 1.

As shown in the drawing, parallel strips I2 and I3, preferably of a light metal of suitable width and thickness and of unequal length, form a straight edge bar and are held apart at one end by a spacer I4, of like material and suitable thickness, to which the two strips are rigidly secured. Member I5, of metal or other suitable material, is a T-head straight edge of conventional size, slidably mounted in space 22 between strips I2 and I3 for longitudinal movement, and is designed to maintain a xed angle, preferably of 90, with the said straight edge bar by means of machined depressions in the upper and lower surfaces of the said T-head, the sides of which slidably engage the sides of the strips I2 and I3. One end of a member I6 is secured to the upper surface of strip I2, as shown, its other or free end preferably being even with the free end of strip I2. The fixed end of the member I6 has a thicker portion lIGA to provide a slot or recess 26 of suitable height and depth between the member I6 and strip I2. This recess is adapted to receive the narrower tab end of a calibrated transparent when wing nut Il is tightened on bolt 29. This bolt is mounted in strip I2 with its head flush with the under surface thereof. In the arrangement as shown, a strip of blotting paper 2l, or other material of similar purpose, is empaled upon needle point brads or screws 23 slightly protruding from the upper surface of strip I3 near the free end thereof and is positioned directly under the transparent plate II, It acts as a recorder strip or transfer sheet to detect or receive impressions of a colored liquid used to penetrate the veneer. Plate II has a downwardly tapered hole I8, centrally positioned in that portion forming the extension to strip I2. This hole is of suicient size to permit the introduction of a colored liquid used in conjunction with this device and to receive the spherical head of an airpump I9 or device of similar purpose. A thin soft rubber washer 20 surrounds the point of emergence of tapered hole I8 in the under surface of plate Il and is countersunk therein so as to protrude very slightly below said under surface. Its purpose is to form an air-tight connection between the plate II and the upper surface of the sheet of veneer at the point at which the colored liquid is brought into contact with it.

In using our invention for measuring the slopes of grains through the thickness of a sheet of veneer, it is contemplated that different transparent plates will be used for different thicknesses of veneer to be measured and that the concentric circles 28 scribed on each plate will be calibrated for such thicknesses. The circles 28 scribed on plate I I may be calibrated in any manner desired. However, sincethe slope of wood grains is conventionally measured in the number of inches of longitudinal distance per inch of v rise of the grain, it is convenient to calibrate the the slope of the grain as being more or less than a slope of 1 in 6, 1 in 10, or 1 in 15, where 1 is thickness of the veneer and 6, 10 or 15 are multiples of the thickness. The number of calibrated concentric circles may, therefore, be limited to these three for most purposes, but more may be used if greater accuracy is desired. Accordingly, the formula suggested is where R is the radius of the circles, X is the thickness of the sheet of veneer, and Y is a multiple of X.

Having selected and inserted' in the device the transparent plate calibrated to measure the slope of the grain through the thickness of the 'sheet of Wood veneer to be examined, said sheet is inserted in space 22, as shown in Figure-2 of the drawings, to a suicient depth to bring the grain in question under the center of hole I8 in plate Il. In such position, the T-head" member l5 of the device may be slidably adjusted to engage squarely the edge of the sheet of veneer, thus orienting the longitudinal axis of therdevice perpendicular to the edge of the sheet of veneer. While .in 'this position, a :small cuan-y tity 'of a colored liquid yof low "viscosity is introcluce'd on the 'surface of the sheet of veneer through the hole `Hl in the .plate VIl by means of a dropp'er or similar device. The penetration of this liquid through the bers of Athe veneer is accelerated by mea-ns 'of air pressure applied to the hole t8 by Imeans of the air-pump I9 or other suitable device. In tests, it has been yobserved that the tendency of this liquidv under pressure is to penetrate the fibers vof thev veneer following the slope of the grain. When. penetration has been. obtained and the point 'of 'emergence of the colored liquid from the under surface of the bar composed of two parallel spaced strips of unequal lengthr the shorter of the two having fattached-theretoa's an extension thereof a transparent 'plate bearing concentric circles, said circles being calibrated to indicate the slopes of grains `Ythrough the thickness of the veneer for 4"sheets roi' Apre'cieltemeined thickness, said transparentV plate. having a tapered hole of small diameter at 'the center of said circles, and an absorbent means used in conjunction with said plate and positioned thereunder.

2. Amethodof determining the slopes of grains in Wood' veneers with respect to their deviation from the vertical comprising penetrating the veneer with a liquidl under pressure, registering the points of entry and 5emergence of the liquid, and measuring the horizontal distance between the two 'points 'as a function of the slope.

VJQHN P. LIMBACH.

BENSON H. PAUL.

REFERENCES CITED The following references are 'of record i-n the -ie of this patent:

UNITED STATES PATENTS Number

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