Search Results

THE electric telemeter presents an excellent means for investigating the phenomenon of valve-spring surge. Basically, the telemeter is composed of two differentially connected stacks of thin carbon discs so arranged that, when the apparatus is subjected to strain, the pressure is increased on one stack and decreased on the other. Each stack forms one arm of a Wheatstone's bridge, and the resistances of the stacks vary with the pressure on them, thus slightly upsetting the balance of the bridge. If an oscillograph galvanometer-element be substituted for the usual bridging instrument, the arrangement will be found suitable for making photographic records. To study valve-spring surge, the telemeter is connected across the points of a stiff C-spring, one end of which is held against the valve-spring in such a way that vibrations of the spring are transferred to the C-spring and thence to the telemeter.

A PAPER on Valve-Spring Surge,2 by Mr. Donkin and H. H. Clark, which was presented at the Semi-Annual Meeting of the Society in May, 1927, was presented during the last season by Mr. Donkin at Section meetings in Buffalo, Chicago and Milwaukee. At a meeting of the Cleveland Section he delivered a paper on Valve-Spring Design, part of which is printed herewith. The remainder was a duplication of the Semi-Annual Meeting paper. At each of these Section meetings the subjects of valve-spring surge and valve-spring design were discussed. Some of the discussion was upon part of the original paper in which were compared two valve-springs, the original design vibrating noisily and the improved design being satisfactory.