| 摘要 |
<p>1308993 Making valve cores; rolling A E BISHOP 18 Feb 1970 [26 Feb 1969] 38691/72 Divided out of 1308992 Headings B3A and B3M A valve is made by the steps of turning a valve core having an arcuate external surface with a longitudinally extending slot and impressing a contour design of irregular configuration on at least one side of the slot by introducing a tool member bearing the contour design generally radially into the core. As shown in Fig. 1, rolling apparatus comprises a collet 20 which, carried by a sleeve 21 and reacting against a chuck 22, grasps a valve core 10. Six equally spaced rolling dies 25 are each carried in a block 27 pivotal about a fulcrum 28 secured to the carrying block 29. Clockwise pivotal motion is given to blocks 27 by means of a piston 30 carrying cam projections 31 which co-operate with pivot pins 27a. Piston 30 simultaneously carries chuck 22 and workpice 10 with it. Return movement of the die blocks is accomplished by retractor 35 which is moved to the right by means of sleeve 34 carrying cam 38 which pivots retractor 39. The rolling dies have an arcuate surface 26 shaped to modify the valve core groove to its final desired form. Final grinding removes upset material from the periphery of the valve core. As an alternative to the rolling technique the longitudinally extending groove may be modified to the desired contour by an electrical spark gap apparatus or an end mill of extremely small radius.</p> |
