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Herringbone Hydrodynamic Capstan

IP.com Disclosure Number: IPCOM000095078D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Mullan, PJ: AUTHOR

Abstract

Capstan 10 is supported and driven by shaft 11 in direction D. Tape 12 is provided under tension with an angle of wrap of approximately 180 degrees about capstan 10.

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Herringbone Hydrodynamic Capstan

Capstan 10 is supported and driven by shaft 11 in direction D. Tape 12 is provided under tension with an angle of wrap of approximately 180 degrees about capstan 10.

In the upper right drawing, the herringbone pattern represents a plurality of piezoelectric crystals 20 embedded in the circumferential surface of capstan 10. Without electrical actuation, crystals 20 are flush with the remaining circumferential surface of capstan 10, which together are smooth. When crystals 20 are electrically energized, they elongate to provide a herringbone protrusion above the normal surface of capstan 10. When crystals 20 are not energized, the smooth surface of capstan 10 drags the air under tape 12 causing air lubrication. Thus, tape 12 is not substantially forced to move in direction R. In this condition, tape 10 can be maintained stopped by a braking device, not shown, or by normal frictional drag in the tape 12 path. However, when crystals 20 are energized, the herringbone protrusions create a vacuum underneath tape
12. This causes frictional engagement of the tape 12 surface with capstan 10 and substantially forces tape 12 to be driven in the direction R.

In the lower drawing, piezoelectric crystal 20 is shown with opposite sides having a metallic covering. The opposite metal coverings are connectable to plus and minus sides of a DC power source, not shown, through slip rings not shown. Thus, the piezoelectric operation of capstan 10 can be...