Abstract: Method and apparatus for determining the concentration of dissolved solids in a sample solution. A refractometer has an enclosing opaque housing, a light source directing a substantially collimated monochromatic light beam through, and a hollow transparent-walled prismatic container adopted for holding a liquid solution to be tested. A light sensor is disposed in the refracted path of the light beam and responds to the exact refraction of the beam caused by passing through the liquid solution. A display is actuated by the light sensor and digitally displays the exact refraction as a function of the concentration of dissolved solids in the liquid sample. Method and apparatus are provided for determining the presence of a sufficient amount of the sample and for automatically commencing the testing in the refractometer.

Abstract: An electromagnetically regulated exerciser providing a variable proportioned resistance to the exercising user. A user input device is drivingly connected to a rotatable shaft. Permanent magnets mounted on the shaft rotate within a wound stator. The windings of the stator are electrically loaded by an electronic controller to create proportioned isokinetic exercise resistance. Motion of the input device by the user is opposed by dynamic braking forces generated by the electrical loading device, and the resistance increases proportionally as the user exceeds a preselected reference speed, effectively regulating user induced motion generally at the preselected reference speed.

Abstract: An exercising device which yields a variable, programmed speed for regulating the user's movement is disclosed. The device includes a user interfacing device for input of the user's efforts, a variable speed regulator connected to and driven by the interfacing device, a user position sensor also connected to the interfacing device, and a speed programmer connected to both the position sensor and the variable speed regulator. By means of a varying references voltage which it delivers to the speed regulator, the programmer establishes a preselected pattern of varying speed to regulate the user's movement. The user position sensor may take a variety of forms. It may sense the absolute position of the user in the range of motion of the exercise, it may measure the distance of the user from the starting point, or it may calculate the user's position according to time elapsed from the beginning of movement in the exercise.

Abstract: A portable folding orthopedic seat unit for use on a chair, automobile seat, or the like. A semirigid seat member is hinged to a back member. Vertical rigid support means extends from the bottom to the top of the back member and supports a back-support assembly, comprising two separate, generally elliptically-shaped, padded back-support members, spaced apart from each other, and a substantially vertically rigid and laterally flexing connecting member joining them together. The connecting member serves to transfer forces from one back-support member to the other. Releasable locking means holds the assembly at a selected vertical position on the rigid support means.

Abstract: A proportioned resistance exercising apparatus capable of exercising two limbs synchronously or separately with a single resistance mechanism. Two limb-engageable drive input devices are connected through one-way clutches to a single rotary shaft, which is, in turn, drivingly connected to the proportioned isokinetic resistance-producing mechanism.

Abstract: Torque stress on a stationary or rotating shaft is measured in a contactless fashion utilizing differential optical sensing means. A pair of light-controlling discs are attached to opposite ends of a torsioning section of the shaft. The combination of light-valving discs comprises two areas, inner and outer, with complimentary light transmission control effects in response to differential angular rotation of the discs with respect to each other. Light is passed through the combination of discs and received by sensors aligned such that separate signals are generated from light passed through the inner and outer areas of the light-controlling discs. As torque is applied to the shaft in one direction, more light is transmitted through the one area, and less through the other. As torque is applied in the opposite direction, the opposite effect occurs. Over angles of such differential rotation of the discs, a stable signal is produced by the sensors that is proportional to the applied torque.