Snap-on Tools Corporation

Jerome A Thompson

Donald D Grover

Thomas P Becker

Gene E Olson

Christopher B Stout

Glenn A Kaufman

The probe includes a tubular housing having a first portion and a second portion. The first portion is adapted to be mounted in place of the glow plug of a selected engine cylinder. A light pipe within the first portion directs light from the combustion zone to a phototransistor within the second portion. The front of the first portion has a reduced size aperture defined by an internal shoulder against which the front of the light pipe is seated. The rear of the first portion carries resilient sealing means which is deformed when the second portion is telescoped thereon so as to provide a detachable, frictional, light-tight thermally insulated connection therebetween. A phototransistor is mounted within the second portion to convert light passing through the light pipe into electrical signals. A cable carries these electrical signals to processing equipment. A base resistor is located in the second portion between the base of the phototransistor and the cable. The part of the first portion that projects from the engine is short with respect to the part that fits into the engine. The projecting portion carries wrench-engaging bosses.

Luminosity probe for diesel engine timing apparatus

The apparatus comprises a luminosity probe to provide an electrical signal in response to the combustion event in a diesel engine and also comprises a probe to provide another electrical signal indicative of top dead center. Both electrical signals are processed and applied to a circuit which generates an output pulse having a duration corresponding to the time between the start of the electrical signals. A meter displays the angle represented by the duration of such pulse. Circuitry is provided to compensate for offset.

Diesel engine timing apparatus

A self-adjusting engine timing pickup probe adapted to be received in a tubular engine mounting bracket, the probe extending into close proximity with a position indicator on a rotating engine part to provide an air gap. An elongated sensor assembly extends through the tubular member and has relative axial movement therewith for initial manual adjustment of the sensor assembly to provide an effective air gap. Interference means are provided between the tubular member and the sensor assembly, the interference means establishing substantial resistance to relative axial movement between the tubular member and the sensor assembly. The tubular member has a spring means which engages the engine mounting bracket and holds the two together in a yielding manner. The spring means urges the tubular member and associated sensor assembly inwardly toward the rotating engine part. However, during engine operation, the rotating engine part, due to tolerances, wear, vibrations, etc., engages the sensor assembly and tends to move both the sensor assembly and the tubular member outwardly of the mounting bracket. In so doing, the spring means holding the tubular member in the engine mounting bracket yields, while the interference means between the tubular member and the sensor assembly does not yield. Thus, the engagement between the sensor assembly and the rotating engine part does not cause relative axial movement between the tubular member and the sensor assembly.

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Milford, MI, United States of America

Jerome A Thompson