United Technologies Automotive Inc.

Essex International, Inc.

Hugh C Webber

David V Tinder

An improved method and apparatus are provided for making vibration sensors, particularly of the type used in automotive applications wherein a piezoelectric element is affixed to a flexing plate which is mounted on a support stem in 'umbrella' fashion. A desired resonant vibrating frequency of the sensor is obtained by progressively working a neck portion of the support stem, as by peening, to effectively decrease the vibrating radius of the plate and thus increase its resonant frequency toward and to a desired resonant frequency. The plate's frequency is monitored and the working of the stem neck portion is terminated when a desired resonant frequency is attained. An inclined support shoulder on the stem below the neck portion facilitates the aforementioned manufacture. An undercut positioned in the stem neck portion near its transition into the support shoulder further facilitates the manufacture.

Vibration sensor and the method of and apparatus for manufacture thereof

Magnetic circuit apparatus for use in an electronic ignition system of a combustion engine having one or more spark ignition devices comprises a magnetically permeable frame on which is supported a field magnet and a Hall Effect pulse generator in spaced apart relation such that the field magnet and frame provide a magnetic flux path to which the pulse generator periodically is exposed to produce successive pulses in timed relation to the speed of operation of the engine. A bias magnet confronts the pulse generator at that side of the latter which is opposite to the field magnet and has a polarity opposite that of the field magnet. The flux density of the bias magnet is substantially less than that of the field magnet.

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Detroit, MI, United States of America

Hugh C Webber