H Effenberger1, M Imhof, U Witzel. 1. Institut für Konstruktionstechnik, Fakultät für Maschinenbau, Forschungsgruppe für Biomechanik, Ruhr-Universität Bochum, Deutschland. H.Effenberger@telering.at
Abstract
INTRODUCTION AND AIM OF STUDY: The screw-in behaviour and correct positioning of threaded cups is largely determined by the design of the thread. Up to now the various thread designs have not been systematically classified. METHODS: The thread designs of 10 first generation and 27 second generation threaded cups were analyzed using a tool setter and a no-touch light section technique. The following parameters were evaluated: thread shape, pitch, number of turns, rows of teeth, tooth length and shape. RESULTS: Threads of the first generation were V-cut or saw shaped. Thread depth was 3.1 mm on average; the mean width was 0.9-3 mm. Single-thread patterns predominated. The number of turns ranged from 1-7; the pitch was from 2.5-5 mm (single thread), or up to 20 mm (triple and quadruple threads). Cups had 3-16 rows of teeth. Threads of the second generation are V-cut, saw or flat shaped. Thread depth is 3 mm on average; mean width ranges from 0.3-2.2 mm. 72% of the threads have single-thread patterns. The number of turns ranges from 2-5; the pitch is from 2.5-6.2 mm (single thread). Cups have 4-24 rows of teeth. CONCLUSIONS: There are many different thread patterns with widely varying parameters. Contemporary threaded cups have a narrow V-cut and saw shaped threads or flat thread with depths up to 3 mm, no more than 5 turns, and pitch values of approx. 4.5 mm.
INTRODUCTION AND AIM OF STUDY: The screw-in behaviour and correct positioning of threaded cups is largely determined by the design of the thread. Up to now the various thread designs have not been systematically classified. METHODS: The thread designs of 10 first generation and 27 second generation threaded cups were analyzed using a tool setter and a no-touch light section technique. The following parameters were evaluated: thread shape, pitch, number of turns, rows of teeth, tooth length and shape. RESULTS: Threads of the first generation were V-cut or saw shaped. Thread depth was 3.1 mm on average; the mean width was 0.9-3 mm. Single-thread patterns predominated. The number of turns ranged from 1-7; the pitch was from 2.5-5 mm (single thread), or up to 20 mm (triple and quadruple threads). Cups had 3-16 rows of teeth. Threads of the second generation are V-cut, saw or flat shaped. Thread depth is 3 mm on average; mean width ranges from 0.3-2.2 mm. 72% of the threads have single-thread patterns. The number of turns ranges from 2-5; the pitch is from 2.5-6.2 mm (single thread). Cups have 4-24 rows of teeth. CONCLUSIONS: There are many different thread patterns with widely varying parameters. Contemporary threaded cups have a narrow V-cut and saw shaped threads or flat thread with depths up to 3 mm, no more than 5 turns, and pitch values of approx. 4.5 mm.