Abstract: A hitch for a machine such as an agricultural tractor permits controlled towing of an implement behind the machine. The hitch has a frame attached to the machine and a subframe mounted to the frame for movement about a first or pivot axis with respect thereto. A mast is attached to the subframe so that it may pivot relative to the subframe about a second or pitch axis perpendicular to the pivot axis. The mast has a hitch element and a carrier positioned in movable engagement one with the other to permit relative elevational movement of the hitch element. The hitch incorporates multiple degrees of movement in a compact package and is useful as a steerable component of the machine to provide positive steering force.

Abstract: RF modulation spectroscopy of a near-infrared tunable laser diode source is used to determine the oxygen concentration in a sample medium. A reference cell containing a known concentration of oxygen is used to calibrate the apparatus as well as to lock the laser on an oxygen absorption line. The temperature of the reference cell is monitored from which the pressure in the reference cell can be determined. Both the temperature and the pressure in the sample cell are monitored, either directly using independent transducers or indirectly using spectroscopic techniques. The oxygen content of the sample is determined, correcting for both temperature and pressure effects.

Abstract: A sleep awakening device awakens drivers of motor vehicles who are falling asleep while driving. The sleep awakening device includes a pair of eyeglasses and a control unit electrically connected thereto to provide both visual and audible warnings to alert a driver who is falling asleep. The pair of eyeglasses include a sensing lever that is in constant contact with one of the driver's upper eyelid muscles. Downward motion of the eyelid moves the sensing lever downward and actuates a microswitch that is coupled to the sensing lever. The microswitch in turn actuates circuitry located in the control unit to turn on a light each time the driver closes his eyelid. The circuitry includes a time delay relay that initiates an audible signal if the eyelid remains closed for a preset period of time. A normal blink of a driver's eye does not produce an audible alarm. However, if the driver's eyelid fails to open in a predetermined time, the audible alarm will sound.

Abstract: RF modulation spectroscopy of a near infrared laser diode source is used to determine the amount of a target substance in a breath sample. In this type of modulation the laser output is modulated to produce sidebands displaced from the laser carrier by the modulation frequency. The modulated beam is passed through a gas sample which differentially absorbs the sidebands, the result of which is the conversion of some of the laser frequency modulation into amplitude modulation which is subsequently detected using a broadband photodetector. In certain tests, the target substance is a particular isotope, whose concentration is measured as an isotope ratio. In order to measure the presence of first and second isotopic species, provision is made to provide laser illumination at characteristic wavelengths for absorption lines for the first and second isotopic species of the gas.

Abstract: An apparatus and method for measuring an unknown voltage using electro-optic materials includes a beam transmitter, voltage sensor, and a receiver. The beam transmitter generates an electro-magnetic beam directed at an electro-optic material in the sensor. The electro-optic material has a voltage gradient across it due to the unknown voltage. The beam is such that it has components both parallel and perpendicular to the direction of the voltage gradient so that passing through the electro-optic material creates a phase difference between the parallel and perpendicular components. This beam with the phase difference passes to the receiver where the beam passes through a compensator formed by another electro-optic material subjected to a voltage gradient from a measurable voltage. The measurable voltage is controlled to produce another relative phase retardation which compensates for the phase retardation produced at the sensor.

Abstract: A lock (1) is mounted to a door (2) of a safe. The lock (1) comprises a housing (4) slidably mounted to the door (1) and movable in the directions indicated by an arrow (3) between locked and unlocked positions upon actuation of the lock. A lock override system (15) is coupled with the lock (1) and is responsive to an override control signal to cause the housing (4) to move relatively to the door and thereby to cause the lock member (8) to move between its locked and unlocked positions.

Abstract: A spectroscopic technique in which the sample under investigation is probed with a generally monochromatic beam of light which has been modulated at two distinct modulation frequencies. The double modulation produces a plurality of sidebands, and the two modulation frequencies are related to one another such that a selection of sidebands falls into two groups of closely spaced component sidebands. A first group is disposed in frequency at the spectral feature of interest and serves to probe the spectral feature. The other group is disposed in frequency remote from the feature and serves as a reference group. Within each group the component sidebands are offset from one another by a characteristic offset frequency, which can be considerably less than the width of the spectral feature under investigation.

Abstract: An inverted channel member is placed over a surface having particulate or similar matter upon it. Air is forced through the channel member to create a vacuum within the member which causes the matter upon the surface to be picked up and blown from the surface and out the channel member.