The United States of America As Represented by the Secretary of

Other

Director, Bureau of Engraving and Printing, Department of the Treasury

Dennis E Gunderson

Roland L Gleisner

John F Hunt

Eric G Gunderson

Vance C Setterholm

Steven G Hankel

C Timothy Scott

The disclosure describes an apparatus for measuring the static and kinetic friction properties of sheet materials. The apparatus comprises a sled, moving table, means for creating and measuring the friction force between sled and table, and lift mechanism which places sled on table, and removes sled from the table. Novel aspects include a lift design which causes the sled to be maintained in positive contact with the force measuring means, friction force creating means which integrate a small displacement static forcing means with a mechanically stiff kinetic drive, and sled construction which securely clamps a flat test-piece on a flat plate.

Apparatus for measuring static and kinetic friction properties

An apparatus for measuring the static friction properties of materials. The apparatus has a means for applying shear force to a sled and table interface in a smooth and repeatable manner. The apparatus operates without operator interference in terms of placing a load on the material to be tested. The apparatus contains a shear type load cell which operates at the same location in the apparatus at which the shear force is applied to a contact interface and at which static friction is generated.

Apparatus for measuring static friction properties

An apparatus and method uses vacuum restraint, or other pressure differenl, to hold the ends of a sheet specimen to two opposing surfaces, thereby creating a fold in the specimen. As the opposing surfaces cycle along a parallel axis in opposite directions, the fold repeatedly rolls through a specific region of the specimen. The spacing between the opposing surfaces can be adjusted to increase or to decrease the radius of the fold. The velocity of the fold and the number cycles also can be controlled precisely. After repeated movement of the fold, the adhesion of surface treatments, coatings or printing on the specimen substrate begins to break down. Additionally, the integrity of the substrate itself may begin to deteriorate, if it is susceptible to deterioration and to varying degrees depending upon the susceptibility. The extent to which the specimen coating is degraded and substrate integrity reduced is a function of spacing, fold velocity and number of cycles.

Method and apparatus for evaluating fold endurance and surface adhesion

An improved method and apparatus for dry forming adhesive coated wood fibers in an airstream in a particular mold apparatus. The invention includes a particular sequence of steps and related apparatus, and permits the manufacturer of a mat of differing cross-sectional shapes but of uniform density. The invention includes the advantageous steps of final curing of the mat off of the main molding apparatus, thus achieving efficiencies in use.

Method for forming structural components from dry wood fiber furnish

An improved apparatus for dry forming adhesive coated wood fibers in an airstream in a particular mold apparatus. The invention permits the manufacture of a mat of differing cross-sectional shapes but of uniform density. The invention includes the advantageous steps of final curing of the mat off of the main molding apparatus, thus achieving efficiencies in use.

Apparatus for forming structural components from dry wood fiber furnish

The present invention is directed to a filtering system and method of filtering an aqueous medium, such as water in an aquarium tank. The aquarium water is brought into contact with a filtering medium, preferably a biological filtering medium. The filtering medium purifies the aquarium water by removing impurities from the aquarium water. At a certain time, the water is rapidly removed from the filtering medium, preferably by siphoning action. The process and system provides the biological filtering medium with exposure to air necessary to sustain the life and activity of the bacteria growing on the biological medium. At the same time, the system purifies the aquarium water.

Method for filtering aquarium water

The invention discloses test methods and apparatus for evaluating the mechano-strain response of various materials, particularly paper and related materials. The moisture sorbed by a specimen is evaluated continuously by observing the change in moisture content of the air in a closed volume surrounding the specimen. The relative humidity of the closed air volume is maintained constant (despite changes in the mass of water vapor in the air) by adjusting the physical volume, and thus the total pressure, of the contained air mass. In a second form, the pressure is adjusted directly. Moisture sorbed by the specimen is calculated from the rise in internal pressure of the closed air mass needed to hold relative humidity constant.

Method and apparatus for testing materials using strain and moisture

A sculptured structural fiberboard product is formed using a mold that includes porous forming areas which, in one embodiment, are porous forming mandrels movably mounted on the mold, and liquid impervious thimbles which removably cover the porous areas. A fiber network is formed as water is drained off through the porous areas and the thimbles are moved to gradually unveil the porous areas during the mat formation. When mandrels are used, the mandrels are withdrawn in cooperation with a pressing force applied to the mat to consolidate and dry the web. The porous areas can also act as heat and mass transfer means during consolidation and drying. An alternative embodiment permits formation of laminated products and another alternative embodiment permits close control over the product density during consolidation and drying.

Apparatus for forming uniform density structural fiberboard

An operation wherein a large amount of material is passed through the nip of two rolls and a dryer at high speed using only a small specimen of material is disclosed. A low mass carrier for the specimen is provided. The carrier and specimen are quickly accelerated to the peripheral speed of the rolls and the specimen is passed through the rolls and quickly stopped inside a static dryer. Specific apparatus for carrying out each step of the operation is disclosed.

Process and apparatus for simulating a rolling and drying operation

Method and apparatus for measuring the nip clearance between two rolls rotating close to each other. First and second members are non-rotatably mounted on opposite sides of the nip. Each member has a pair of wheels mounted so that one wheel rotates in contact with only one roll and the other wheel rotates in contact with only the other roll. The nip clearance is a function of the distance between the two members.

Method and apparatus for measuring press roll clearance

An apparatus and method of measuring edgewise compressive deformation in sheet material comprises providing a specimen beam having an inner curved layer of the sheet material to be tested, an outer curved strip spaced radially outwardly of the sheet material, an elastomeric spacer between the sheet and strip, and blocks fixing the opposite ends of the sheet material to the opposite ends of the strip. The spacer is fixed to the backing strip and engaged firmly on the outer radial surface of the sheet material. The ends of the curved specimen beam receive a pure torque which causes compression of the sheet material which can be measured. The sheet material is supported so that it does not buckle with the torque being applied by simple weights connected to rotors which in turn are engaged with the opposite ends of the specimen beam.

Apparatus and method of measuring edgewise compressive deformation

A compressive creep test fixture of box-like structure having a rectangular opening for testing a specimen and a pair of ports for applying a vacuum is provided. Rigid or semi-rigid elements, spaced from each other in a uniform manner, support the specimen at the rectangular opening during testing. The vacuum in the fixture holds the tested specimen in place on the support elements, and together the vacuum and support elements prevent buckling of very thin sheet materials under conditions of edgewise compressive loading. A method for using a compressive creep test fixture to determine mechanical properties of sheet materials.

Method and apparatus for edgewise compression testing of flat sheets

A compressive creep test fixture of box-like structure having a rectangular opening for testing a specimen and a pair of ports for applying a vacuum. Rigid or semi-rigid elements, spaced from each other in a uniform manner, support the specimen at the rectangular opening during testing. The vacuum in the fixture holds the tested specimen in place on the support elements, and together the vacuum and support elements prevent buckling of very thin sheet materials under conditions of edgewise compressive loading. A method for using a compressive creep test fixture to determine mechanical properties of sheet materials.

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Madison, WI, United States of America

Dennis E Gunderson