Abstract: A time division multiplex system for motor vehicles and other applications in which data signals are adapted to be sent through the system in cyclical fashion during each of a series of time periods. The system includes a communication line, a master unit connected to the communication line which includes a pulse-generating circuit for sending a plurality of timing signals out over the line for defining a plurality of time slots during each time period, and a plurality of transceiver units connected to the communication line.

Abstract: A monitoring unit for remotely monitoring liquid levels in a container includes a common probe, a reference probe, and four sensing probes, each mounted to the container in electrical contact with liquid within the container. A liquid level sensing unit measures resistance between the common probe and the reference probe and uses the measured resistance as a threshold to determine which of the sensing probes is in contact with liquid in the container. In this way, the sensing unit is made substantially independent of the resistivity of the liquid in the container. The sensing unit is connected to an evaluating unit by a single conductor, and the sensing unit draws a variable amount of current through the conductor in accordance with the number of sensing probes in contact with liquid in the container. The conductor thus supplies power to the sensing unit and also transmits information from the sensing unit to the evaluating unit.

Abstract: A data entry terminal for storing a plurality of user generated answers is described which includes a removable volatile read/write memory module. The memory module is used to store formatting information used to configure the data entry terminal as appropriate for a particular set of questions. The memory module can for example store a set of correct answers as well as a set of user answers for each of the questions of the test, and it can store data used to disable certain functions of the data entry terminal, such as the ability of a user to revise an initially entered answer. The data entry terminal operates to record user answers in the portable memory module, which can then be removed from the data entry terminal and applied as an input to an external computer for analyzing user responses. The portable memory module includes a battery for powering a volatile semiconductor memory included in the module.

Abstract: A latching relay includes a housing and a coil secured to the housing. An armature is electromagnetically coupled to the coil such that current to the coil biases the armature to a first position. A spring is coupled to the armature to bias the armature to a second position. The relay includes a switch which includes a movable contact coupled to the armature such that the switch is in a first state when the armature is in the first position and the switch is in a second state when the armature is in the second position. A magnet is movable in the housing between a blocking position, in which the magnet acts as a mechanical block to prevent the armature from moving to the second position, and an unblocking position, in which the magnet allows the armature to move to the second position.

Abstract: A power management system for a recreational vehicle operates automatically to disconnect a major electrical appliance, such as an air conditioner, heater or water heater, from power when the current drawn by additional appliances exceeds a preset current threshold. When the current drawn by these additional appliances falls below the threshold, the major appliance is automatically reconnected. A preferred embodiment of this invention operates to alternate between two or more air conditioners, heaters, or the like, to ensure that only one is connected to power at any given time, but that both are activated alternately and in sequence to provide efficient use of both air conditioners. In addition, preferred embodiments of this invention operate to interrupt operation of the air conditioners whenever the power voltage falls excessively low, and to ensure at least a preselected time delay between the time an air conditioner is stopped and restarted.

Abstract: An intravenous set is described which includes a housing which defines three separate chambers: an uppermost valve chamber, an intermediate volumetric chamber, and a lowermost drip chamber. The valve chamber is provided with an externally actuated structure for interrupting the flow of fluids into the volumetric chamber. In alternate embodiments, this valve member can include a magnetically responsive element, a diaphragm, or a pinch tube. A volumetric chamber is provided with a predetermined volume and is adapted for remote sensing of the fluid level inside the volumetric chamber. Fluids pass from the volumetric chamber into the drip chamber where they are formed into individual drops. The drip chamber is adapted to allow remote detection of drop formation and drop counting. A controller is described which, when used in conjunction with the described intravenous set, provides extremely accurately controlled rates of infusion.

Abstract: A controller for an intravenous set is disclosed which operates both to maintain the instantaneous drip rate through a drip chamber included in the IV set at a desired value, and to modify this value repeatedly during the course of an infusion. The desired drip value is modified in accordance with the measured volumetric flow rate through the intravenous set such that if a particular infusion fluid produces abnormally small volume drops in the drip chamber, then the controller automatically increases the drip rate to compensate. In this way, extremely accurate control of the fluid flow rate is obtained without the need for complex infusion pumps. A disclosed embodiment operates to provide separate alarms for open line errors, air in line errors, and occlusion errors.

Abstract: A power management system for a recreational vehicle which operates automatically to disconnect a major electrical appliance, such as an air conditioner, heater or water heater, from power when the current drawn by additional appliances exceeds a preset current threshold. When the current drawn by these additional appliances falls below the threshold, the major appliance is automatically reconnected. A preferred embodiment operates to alternate between two or more air conditioners, heaters, or the like, to ensure that only one is connected to power at any given time, but that both are activated alternately and in sequence to provide efficient use of both air conditioners. In addition, preferred embodiments operate to interrupt operation of the air conditioners whenever the power voltage falls excessively low, and to ensure at least a preselected time delay between the time an air conditioner is stopped and restarted.

Abstract: A control method and apparatus for a metal-forming machine such as a cold heading machine are described. The described method and apparatus monitor machine operation during production and permit relatively large deviations from a prescribed norm over a short term without shutting down the machine, while ensuring longer term compliance to relatively small tolerances from the norm. The described controller first determines an average of a measured parameter such as the hit energy applied to a group of workpieces resulting in acceptable metal-forming during a training mode and then stores this average as a target value. The controller then establishes a set of tolerance windows to be used to control forming operations in a production mode.

Abstract: A teaching device includes a reading station provided with six on-off switches for automatically sensing a text key encoded as a pattern of punched holes in a text book. The teaching device automatically generates an answer key from the text key by means of a pseudo-random number generator which is run using the text key as a seed. The text book includes a number of multiple choice questions in which the correct answer corresponds to the answer designated in the answer key.

Abstract: An automatic note analyzer is disclosed which automatically generates and displays a note signal indicative of the musical note corresponding to an input signal. The disclosed analyzer operates to measure the period of the input signal on a regular basis. According to one aspect of the invention, the measured period is compared with a predetermined window representative of the expected value of the measured period. Measured periods which do not fall within the predetermined window are rejected. According to a second feature, measured signals representative of the period of the input signal are averaged in order to increase the stability of the analyzer. The disclosed analyzer operates in two modes: an absolute mode, and a transposer mode. In the absolute mode the displayed note value is determined with reference to an absolute pitch. In the transposer mode, the displayed note value is determined with reference to a relative pitch which can be readily adjusted as needed.

Abstract: A game apparatus is disclosed having a one-dimensional array of LED's which are sequentially activated in first and second sweep sequences which proceed toward first and second goal indicators, respectively. First and second buttons are provided which operate to reverse the first and second sequences, respectively, and the object of the game is for each player to operate his button before the appropriate sweep sequence causes his goal indicator to be activated. The rate of each sweep is variable and a player can select a higher sweep rate for his opponent by delaying his reaction until a relatively later time in the sweep sequence. The score is displayed on the same indicators as are used to play the game, and successively higher scores correspond in sequence to the sequence in which the indicators are activated during play.