Abstract: The present invention is a wood grading apparatus including a robust “push” solenoid as a hammer means for impacting a lumber specimen under test. A conventional solenoid coil with stationary magnetic iron pole pieces is combined with a bimetallic armature including a magnetic portion and a non-magnetic portion; said armature is of uniform cross section through the solenoid coil. A magnetic steel portion of said armature is fastened to a nonmagnetic steel portion thereof, whereby the magnetic field may act upon the magnetic portion of said armature and drive said nonmagnetic portion in an outward direction whereby impact or striking action is achieved. The present invention includes said solenoid in a wood grading apparatus whereby physical properties of wood are measured in a conveyor line setting and wood grading is affected by combining sonic velocity and density measurements to determine the modulus of elasticity of the wood object.

Abstract: An apparatus for testing panel products in edgewise shear in which the shear stress is applied in a diagonal direction with a first rotational degree of freedom in a first grip means and a second rotational degree of freedom in a second grip means as a first loading configuration. A second loading configuration is provided in which the second rotational degree of freedom of the second grip means is locked in place and motion is prevented. A third preferred method of loading is available in which shear forces in a horizontal direction through a centerline of a specimen, with the centerline in the plane of the specimen and extending across a widest dimension of said specimen. Control and data collection are under computer control and operator safety is enhanced by a locking guard door which is electrically locked while the various parts of the machine are in motion.

Abstract: An apparatus for testing panel products in edgewise shear in which the shear stress is applied in a diagonal direction with a first rotational degree of freedom in a first grip means and a second rotational degree of freedom in a second grip means as a first loading configuration. A second loading configuration is provided in which the second rotational degree of freedom of the second grip means is locked in place and motion is prevented. A third preferred method of loading is available in which shear forces in a horizontal direction through a centerline of a specimen, with the centerline in the plane of the specimen and extending across a widest dimension of said specimen. Control and data collection are under computer control and operator safety is enhanced by a locking guard door which is electrically locked while the various parts of the machine are in motion.

Abstract: The present invention is a wood grading apparatus including a robust “push” solenoid as a hammer means for impacting a lumber specimen under test. A conventional solenoid coil with stationary magnetic iron pole pieces is combined with a bimetallic armature including a magnetic portion and a non-magnetic portion; said armature is of uniform cross section through the solenoid coil. A magnetic steel portion of said armature is fastened to a nonmagnetic steel portion thereof, whereby the magnetic field may act upon the magnetic portion of said armature and drive said nonmagnetic portion in an outward direction whereby impact or striking action is achieved. The present invention includes said solenoid in a wood grading apparatus whereby physical properties of wood are measured in a conveyor line setting and wood grading is affected by combining sonic velocity and density measurements to determine the modulus of elasticity of the wood object.

Abstract: This invention provides a method and apparatus for determining the grain angle of a wood object which has a circular cross section of constant or varying radius along the object's length. This apparatus may be hand-held or fixed mounted as testing circumstances dictate. The resulting grain angle may be displayed in real time, as perceived by the user, or transmitted to a processing unit for data collection or interpretation.

Abstract: This invention provides a method and apparatus for determining the grain angle of a wood object which has a circular cross section of constant or varying radius along the object's length. This apparatus may be hand-held or fixed mounted as testing circumstances dictate. The resulting grain angle may be displayed in real time, as perceived by the user, or transmitted to a processing unit for data collection or interpretation.

Abstract: This improved method of calibrating wood testing machines includes improved test bars, shim and software to direct the operator through the steps of calibration, storing interim results and calculating new calibration factors based on values read when the test bars are placed in the wood testing machine. This method avoids a number of problems in previous methods and apparatus. It properly corrects for changes in deflection in the measurement apparatus and changes in straightness of the test bars. The result is a more stable and reliable calibration that is referenced to precise measurement of the EI product for the test bar.

Abstract: This improved method of calibrating wood testing machines includes improved test bars, shim and software to direct the operator through the steps of calibration, storing interim results and calculating new calibration factors based on values read when the test bars are placed in the wood testing machine. This method avoids a number of problems in previous methods and apparatus. It properly corrects for changes in deflection in the measurement apparatus and changes in straightness of the test bars. The result is a more stable and reliable calibration that is referenced to precise measurement of the EI product for the test bar.

Abstract: Method and apparatus are described for obtaining information about the real and imaginary parts of permittivity in dielectric materials and relating this information to other properties of the materials.

Abstract: Improved apparatus is described for measuring bending stiffness of dimension lumber. Innovative details are introduced that make the measurement more accurate and repeatable as well as making the apparatus simpler, more robust and easier to maintain than the prior art.

Abstract: Method and apparatus are described for using stress wave measurements in the estimation of quality of finger joints in wood and quality of lumber, where quality is typically defined as strength. Application and measurement of stress waves in the transverse direction of the material allows localized measurements to be made, and features developed from this information are used in the quality estimation. A feature is a quantifiable characteristic developed from stress wave signals which can be used either by itself or in combination with other features to estimate quality. Examples of features include the propagation velocity of a stress wave, the attenuation of a stress wave, the difference in stress wave propagation times measured at different locations along the lumber, and the effects on amplitude and phase of frequency components of a stress wave. Treating features together as a feature vector and as input to an estimator function, estimated quality can be evaluated.

Abstract: A spray marking nozzle includes features allowing it to perform well for fast marking of materials. The nozzle utilizes gas as a transport medium to carry liquid to the target material as a spray. Features of the nozzle allow it to be constructed economically in a compact size and to be controlled at high speed with little or no carry over spray and over a wide range of liquid and gas pressures.

Abstract: A method and apparatus for compensating for errors in the measurement of force applied to a load beam interposed between two compliant supports and a load point involves placement of an accelerometer at a selected location on the load beam. Signals produced by the accelerometer are added to a signal produced by a transducer at one of the compliant supports to obtain a composite signal which is compensated for accelerations of the load beam.

Abstract: Wood grain angle information is detected electronically by use of a sensor having a common electrode and a plurality of electrodes spaced from the common electrode and arranged angularly about a sensor axis. The common electrode can serve as a sense electrode or as a drive electrode for the remaining angularly spaced electrodes. By modulating applied drive signals and demodulating the sensed signals that result from capacitive coupling of an adjacent wood specimen, values that are a function of wood grain angle are identified.

Abstract: A flexure coupling includes a backing plate and an adjacent hub, the backing plate being adapted to be mounted to a first machine member and the hub being adapted to be mounted to a second machine member. The hub is supported on the backing plate by a plurality of equiangularly positioned radial springs that permit compliant torsional movement of the hub relative to the backing plate. The springs prevent relative axial or longitudinal translational movement between the hub and backing plate, as well as relative radial movement. Substitution of the flexure coupling for conventional bearings eliminates the problem of false brinelling that results from vibration of stationary bearings.

Abstract: A non-destructive testing system for lumber involves measurement of grain angle about a board and transformation of the measured grain angle values to extract features indicative of knot identification, grain angle perturbations or strength of the board. Individual boards can then be processed for grading or sorting purposes as a function of the extracted features. Specific features utilized for knot identification are curl, divergence, and novel transformations termed gradient, edges and knots, as well as various pattern matching techniques. Strength estimation involves transformations pertaining to failure distance, which is a function of board tensile strength. Failure distance can be computed by an ellipsoidal model, a search model or a tracks model. When utilized in conjunction with conventional bending test procedures, highly accurate strength estimation is achieved by the described system.

Abstract: A lumber testing apparatus incorporates opposed wedges to simultaneously exert tension and clamp forces on boards being tested. The inclined wedge surfaces utilize bearing materials and wedge angles selected to match the required clamp forces to tension forces on each board, without crushing the boards at high loads. This is accomplished by using bearing materials having a variable coefficient of friction under varying load conditions.

Abstract: A device for testing sheet material, such as wood veneer, includes a rolling transducer for introducing ultrasonic signals into the veneer so as to cause travel of the signals generally in the plane of the veneer. Coupling oil filling this transducer facilitates the transmission of the signals into the veneer. Another similar rolling transducer is provided to detect the travelling ultrasonic signals. Each rolling transducer includes a special rim with an annular focusing ring for directing the ultrasonic signals to and from the veneer. A timer circuit produces a signal representing the travel time taken for an ultrasonic signal to pass between the transducers. An averaging circuit obtains an average of such travel times for each sheet and a grading circuit causes the sheet to be marked with a grade corresponding to the average travel time. A signal threshold detector prevents travel times for detected signals of a magnitude less than a preselected minimum level from being included in the average.