Abstract: A dilatant circumaural hearing protection earcup soft seal is disclosed. The design of the instant invention is predicated on the theory that the primary function of an effective earcup soft seal is to hold the earcup it is attached to stiffly against the user's head. Experimental evidence shows that an earcup is “pumped” in response to acoustic pressure and reconstructs the acoustic signal inside the earcup as a diaphragm, even though very little noise may pass directly through the earcup itself. The soft seals of the instant invention utilize the dilatant property of some materials to provide a soft seal that conforms slowly and comfortably to a user's head but is stiff under the influence of high shear rate acoustic pressure.

Abstract: A multi-technology acoustic energy barrier and absorber is disclosed that employs the teaching of U.S. Pat. No. 5,400,296 for a matrix material with at least two species of particles with differing characteristic acoustic impedances, in combination with the teaching of U.S. patent Pending Ser. No., 08/780,271, for an "Acoustic Absorption or Damping Material with Integral Viscous Damping," and with the principles underlying constrained-layer dampers.

Abstract: Acoustic absorption or vibration damping materials are produced by mixing at least two species of particles into a restricted amount of matrix material in order to produce an acoustic absorption or vibration damping material with tortuous passageways throughout the material. The tortuous passageways of the instant invention serve to: a) reduce acoustic reflectivity at the surface, b) provide channels within which the interfacing medium such as air can interact viscously, c) increase the surface area between interfacing media and, d) improve structural stiffness by adding thickness without adding weight. Particle species within the matrix material are differentiated by their acoustic impedances. A particle species of particular interest is crumb tire rubber from used tires. This material is inexpensive and its use in this application has the societal advantage of making productive use of a material that is currently polluting the environment.

Abstract: A panel spacer is disclosed that enhances the natural damping characteristics of the material used for construction. The spacer is shaped to redirect acoustic and vibrational energy into a direction parallel to the panel surfaces and to take advantage of the faster energy propagating through the material of the spacer relative to surrounding gasses. Energy propagating through the spacer will arrive at a mid-point of the spacer well before sound originating from the same source can reach the same point through air or another gas. The phase discrepancy between the induced displacements of the spacer and the surrounding gas is used to dissipate energy by causing the spacer to interacting viscously with the gas.

Abstract: Acoustic absorption and vibration damping materials are produced by mixing electrically conductive particles or strands into a piezoelectric matrix material. The electrically conductive particles or strands act as small localized electrical short-circuits within the matrix material and effectively dissipate the electric charges produced by piezoelectric effect from the pressure of acoustic or vibrational energy as heat. All energy thus converted into heat is subtracted from the original acoustic or vibrational energy, resulting in acoustic absorption and/or vibration damping.

Abstract: A telescoping robot arm with singularity-free three degrees of motion freedom spherical joints is disclosed. The telescoping section and spherical joints are hydraulically operated to achieve a high power-to-weight ratio and use conventional seals of the type normally used on hydraulic pistons. The spherical joints of the instant invention are comprised of a generally spherical cavity containing a tiltable member with integral a retractable arcuate vanes interdigitized with retractable arcuate vanes in a non-tiltable member. A plurality of cavities is formed within the spaces between the interdigitized arcuate vanes of the instant invention, with the volume of these intervane cavities being controlled with an equal plurality of hydraulic valves. A plurality of spherical joints of the present invention may be interconnected with double acting telescoping sections of the present invention to form a robotic arm assembly.

Abstract: A means of enhancing the acoustic attenuation and vibration damping of a material by embedding high characteristic acoustic impedance particles, low characteristic acoustic impedance particles, or both high and low characteristic acoustic impedance particles within the matrix of the material is disclosed. The mass of the resultant material may be very low while retaining excellent acoustic attenuation, vibration damping, and structural characteristics. When particles with mismatched characteristic acoustic impedances are embedded within the matrix of a material that can support shearing loads, propagating acoustic energy that encounters the particles of the instant invention is partially reflected in random directions. That is, the propagating energy is diffused. As the propagation vectors and modes of acoustic energy are effectively randomized, the probability of localized energy absorption and damping is increased.

Abstract: An improved compound bow apparatus with extreme let-off and high power is disclosed. The preferred embodiment of the instant invention is aesthetically improved, has inherently balanced limbs that require no adjustment, and has an improved dynamic balance and center of gravity. These and additional objects of the invention are accomplished by storing energy in a leaf spring energy storage device as the bow of the instant invention is drawn. Energy is stored by rotating bearing surfaces mounted on linkages attached to upper and lower bow limbs into a leaf spring in a manner that causes a portion of the force from the leaf spring which is proportional to the rotation angle to be absorbed as compression by the linkage, with the remainder causing torque on the upper and lower bow limbs. The movement of upper and lower bow limbs of the instant invention is coordinated with a synchronizing cable, but the force applied to the individual linkages is inherently balanced by allowing the leaf spring to freely pivot.

Abstract: In order to protect the eyes or other sensor, from light produced, e.g., by odern laser weapons which have extremely fast onset times and high power per pulse, a protective shutter device is provided which is based on the integrative property of such sensors. The sensor is shielded for a large proportion of the time and only exposed after a light detector associated with the protective device has assured a safe environment. The normal exposure provided is a series of rapid image-views that integrate over time within the sensor. In an eye goggles embodiment, clear vision is maintained and a fast-response variable-density "sunglass" is perceived by the wearer. Only one eye is exposed and thus at risk at any one time, and that eye only about 10% of the total time. A high-speed mechanical shutter controls the exposure experienced by the sensor.

Abstract: An injection molding method and apparatus is disclosed that enables the injection of molding material into molds that may contain fibers, long, oriented fibers, core inserts and/or surface inserts. The method utilizes these steps: first, evacuation of the mold and its contents with the use of a vacuum means to remove gasses, adsorbed and chemisorbed water and other substances, second, injection of material into the mold using an injection pump or atmospheric pressure to force molding material into the mold. Apparatus for the preferred embodiment includes the placement of molds and any mold contents in a vacuum chamber to eliminate a dependence on seals around the mold, and means for injection of molding material under vacuum.

Abstract: A Scheiner-principle optometer for automated assessment of accommodative state is disclosed. The specific advantages of the instant invention over earlier ones are: a) simplicity of design, b) hand held, portable implementation, c) light weight, d) small size, e) low manufacturing cost, and, f) the use of a monochromatic light source to eliminate the effects of chromatic aberrations in the subject's eye.

Abstract: A method and optometer apparatus for measuring the accommodative state of eye of a subject is disclosed. In a preferred embodiment, the optometer apparatus includes: a pinhole aperture plate having a center and a plurality of apertures in the pinhole aperture plate for viewing by the subject's eye; a positive lens disposed near the pinhole aperture plate and having an optical axis coincident with the center of the pinhole aperture plate; and scaled means inclined away from the positive lens for indicating to the subject the accommodative state of the subject's eye in diopters.

Abstract: In a preferred embodiment, the optometer apparatus includes: a pinhole apure plate having first and second horizontally positioned apertures disposed on opposite sides of a first optical axis; first and second orthogonally-oriented polarizing filters respectively covering the first and second horizontally positioned apertures; a positive lens having an optical axis on the first optical axis and being positioned at a distance of approximately one focal length from the pinhole aperture plate; a lens system having an optical axis on the first optical axis; a slit aperture plate having a vertical slit and being disposed on the first optical axis and between the positive lens and the lens system; third and fourth vertically positioned polarizing filters selectively disposed adjacent to the slit aperture plate to divide the slit vertically, the third and fourth polarizing filters being respectively oriented parallel to the first and second polarizing filters; a monochromatic light source for propagating light along