Abstract: An input overload protection circuit particularly suited for use with a high impedance differential amplifier having two inputs is provided. The protection circuit prevents the flow of substantially all leakage currents for input signals within the linear operating range of the amplifier, and includes a first and second serial plurality of diode-action clamping means, such as diodes, connected respectively between the first and second input conductors to the amplifier input and a third conductor connected to a reference potential. Driven guard means operate to apply the voltage appearing on the respective first and second input conductors at their junction with the respective first and second clamping means to the respective first and second plurality of clamping means intermediate the respective ends thereof, thereby to substantially prevent leakage current from flowing through the clamping means from the pair of conductors.

Abstract: Glass lenses or lens blanks, containing all the ingredients necessary to produce phototropic or photochromic behavior, are treated in a conventional production furnace to produce a locally variable heat treatment, wherein at least one portion thereof is raised to a temperature exceeding the glass strain point but not the softening point, and other portions are heated to variable temperatures decreasing from the strain point. The treatment causes development of phototropic or photochromic behavior only in those portions of the lenses or lens blanks exposed to the temperature above the strain point.

Abstract: A lens suitable for implantation in the eye is provided with iris clips formed of plastic filaments each having at least one of its ends fastened to the lens. Ends of the clips to be fastened are ferruled and beaded for secure and permanent affixation.

Abstract: A stop for an instrument focusing shaft wherewith the extent of its rotational excursion in one direction may be readily adjusted and repeated. A gear fixed to the focusing shaft and in mesh with additional gearing is selectively stopped by another gear caused to mesh across two gears of the system. The stop gear may be carried out of mesh by reverse rotation of the focusing shaft.

Abstract: Glass lenses or lens blanks, containing all the ingredients necessary to produce phototropic or photochromic behavior, are treated in a conventional production furnace to produce a locally variable heat treatment, wherein at least one portion thereof is raised to a temperature exceeding the glass strain point but not the softening point, and other portions are heated to variable temperatures decreasing from the strain point. The treatment causes development of phototropic or photochromic behavior only in those portions of the lenses or lens blanks exposed to the temperature above the strain point.

Abstract: A short fiber optic image transmitter receives an image produced by a fiberscope objective and transmits the image to the image receiving end of the flexible fiber optic bundle of the fiberscope. The short image transmitter is oscillated about an axis normal to its direction of image transmission for causing images transmitted thereby to scan across the image receiving end of the fiberscope bundle. Synchronous scanning of the opposite image emitting end of the fiberscope bundle renders the received images stationary and of enhanced resolution.

Abstract: Providing visual means for indicating when vapor/gas respirator cartridges have exhausted their capacity to provide respiratory protection at or below a hazardous concentration level. In combination with a vapor/gas indicator adapted to undergo a change in color with contact by an organic vapor or gas, there is provided a catalytic agent for enhancing activation and reaction of the indicator agent.

Abstract: An improved method and apparatus for determining blood pressure in a system employing a variable pressure cuff and having means for sensing a quantity comprising the sum of applied cuff pressure and a component representative of pulsatile pressure in a blood vessel, a particular time derivative of at least the fluctuating component of the quantity is obtained and utilized for determining blood pressure. More specifically, the particular time derivative comprises the second (or greater) derivative and it is analyzed to determine at what applied pressure it first and last crosses a negative threshold value, those pressures then being indicated as diastolic and systolic pressure depending on whether applied pressure is increased or decreased. The threshold value may be dynamically determined.

Abstract: A lens suitable for implantation in the eye is provided with laterally extending iris clips each having at least one of its ends locked within the body of the lens. The clips are initially extended through close-fitting openings, terminally beaded and forcefully retracted sufficiently to bury their beaded ends within the lens body. Cold flow of lens material around the beaded ends locks the clips in place.

Abstract: A method of treating ophthalmic quality lenses or lens blanks that produces a reversible progressive local variation in phototropic behavior with a continuous variation in transmissivity. The lens or lens blank is composed of a potentially phototropic glass containing all the necessary ingredients including uniformly dispersed silver halide particles therein to develop a phototropic behavior during the heat treatment of the present method. The steps of the present method include mounting the lens or lens blank in carrier means, heating the lens or lens blank thus mounted in a heat treatment furnace at a temperature sufficient to develop the phototropic behavior of the potentially phototropic glass. Characteristically the required heat treatment temperature to develop this phototropic behavior is one which exceeds the strain point of the glass but not the softening point thereof.

Abstract: In cardiac signal processing apparatus, there is provided improved means for suppressing pacer signal artifacts, including both the discharge pulse and the recharge waveform (tail) of such artifact. Rate-limiting circuitry is used to substantially suppress the discharge pulse. However additional circuitry responsive to the detection of a pacer pulse is operative to obtain a measure of the electrical discharge of the discharge portion of the respective pacer pulse and to use such measure to generate a tail suppression signal which, when added to the original signal, substantially cancels the original pacer tail.A feed-back loop is opened by the rate-limiter when a pacer pulse occurs and in turn permits a large signal to be imposed on a threshold-level-type pacer pulse detector for connecting the large signal (pacer pulse) to a capacitor during the discharge portion of the pacer pulse.

Abstract: A self-aligning and centering tool and tool holder system for lens surfacing apparatus. The tool and holder are provided with readily manually assembled and disassembled interlocking faces for precise automatic rotational alignment and centering or decentering of the tool without affect by wear from the abrading action of surfacing.

Abstract: A safety razor contains a blade cartridge in which two blades are rigidly secured. The cartridge has a seat member with an integral blade edge guard disposed transversely along its forward margin. A first razor blade is disposed on a planar surface of the seat member and has its cutting edge located rearwardly of the guard. A second razor blade having a cutting edge located parallel to and rearwardly of the first blade edge is in contact with a mating surface of a cap member. The cap member is secured to the seat member thereby clamping the blades in desired position. The blades are maintained at a predetermined distance apart by spacing means and the guard member has a plurality of projecting teeth transversely arrayed across the guard member forming a comb guard.

Abstract: An improved fast-recovery circuit for ECG amplifiers and the like. The fast-recovery circuit includes threshold responsive circuitry connected in parallel with part of the resistance associated with the integrator in a feedback circuit of the amplifier. The threshold responsive circuitry operates to increase feedback frequency response of the integrator when the normally very low frequency output signal of the amplifier exceeds a certain threshold. The improved circuit prevents the threshold circuitry from responding to pulses or excursions in the output signal of a relatively higher frequency content and which exceed the amplitude threshold for less than a predetermined interval, as for instance caused by pacer spikes, large QRS complexes and the like. Preferably, the improved threshold responsive means comprises transistor means connected across the integrator's resistance and having capacitance means across the base-emitter circuit thereof for inhibiting response to certain short duration signals.

Abstract: A gas or vapor sensing and alarm device in an air purifying respirator for warning the wearer of hazardous levels of gases or vapors penetrating through the respirator cartridge. An exothermic sensor which can be fitted in the cartridge adaptor or facepiece cavity of the respirator monitors the heat evolved during adsorption of the vapor or gas into the sensor's adsorbent and triggers in alarm when the respirator cartridge has reached the end of its service life.

Abstract: An interference filter having a plurality of alternating layers of high and low index of refraction and layer thickness increasing toward the center can compensate for errors in spectral energy distribution produced by an optical system.

Abstract: Contact lens sterilizer has a timer operating a catch for holding a capsule containing contact lenses in sterilizing solution in a sterilizing position. In this position, the capsule is inclined toward inversion. When the timer releases the catch after a predetermined period of time, the capsule swings to a substantially inverted position. In this position, a catalyst contained in one end of the capsule contacts the sterilizing solution to neutralize the same. Optionally, a lock mechanism prevents removal of the capsule from the sterilizer until neutralization is complete.