Tachometer apparatus
OwnerThomas G. Fariainventor
Life of this patent
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Abstract
The invention contemplates tachometer apparatus which functions from an electric pulse input which is of frequency directly related to engine speed of an internal combustion engine. In application to a modern automobile assembly line wherein successively assembled vehicles may have various-sized engines in random succession, the particular feature of the invention is that with essentially the same rectifier circuit and associated indicating meter, and with the simplest of manipulation or connection of a single element, the meter can be direct-reading and fully calibrated whether the invention is applied to a four-cylinder engine, to an eight-cylinder engine or to a six-cylinder engine.
Claims18
Electric tachometer instrumentation having selective adaptability to each of a plurality of engine configurations having different numbers of cylinders and adapted to function in response to a pulsating input signal characterized by pulses of alternating polarity and for which the pulsating frequency bears a direct relation to a speed to be measured, said instrumentation comprising a full-wave rectifier bridge having four arms serially connected at four corner terminals, a first pair of opposed terminals being adapted to receive said input signal, current-measuring means connected across the other pair of opposed terminals, and selectively operable means including on-off switch means connected in shunt across one of said arms;
- whereby in the OFF-selected position of said switch means, said measuring means will correctly produce an engine-speed measuring response for an engine of a first number of cylinders;
- and whereby in the ON-selected position of said switch means, said measuring means will again correctly produce an engine-speed measuring response for a similar engine having a greater number of cylinders.
Electric tachometer instrumentation having selective adaptability to each of a plurality of engine configurations having different numbers of cylinders and adapted to function in response to a pulsating input signal characterized by pulses of alternating polarity and for which the pulsating frequency bears a direct relationship to a speed to be measured, said instrumentation comprising a full-wave rectifier having four arms serially connected at four corner terminals, a first pair of opposed terminals being adapted to receive said input signal, current-measuring means connected across the other pair of said opposed terminals, whereby said measuring means may correctly produce an engine-speed measuring response for an engine of a first number of cylinders, and selectively manipulable means including an electrical conductor connected at one end to one terminal of the other pair, whereby upon selective connection of the other end of said conductor in effective shunt of half of said rectifier, said measuring means may correctly produce an engine-speed measuring response for a similar engine having a greater number of cylinders.
Dependencies are inferred from the claim text.