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Flat Belt Drive Precision Speed Control Trimming Mechanism

IP.com Disclosure Number: IPCOM000090633D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Gilmore, JC: AUTHOR [+3]

Abstract

This is a drive for magnetic disk 9. Synchronous motor 1 is mounted on platform 3 which is pivoted about axis 4. Screw 5, forcing against spring 6, is rotatable to move platform 3 and motor 1 up or down. Motor 1 drives shaft 2. Flat belt 7 connects shaft 2 and shaft 8 that rotates disk 9. When platform 3 is moved up and down, the tension in belt 7 is varied and this varies the belt creep. The belt creep, inches/pulley revolution, is equal to 2 pi R (F1 - F2)/K. R equals the pulley radius, F1 equals the belt tension on the tight side of the pulley, F2 equals the belt tension of the slack side of the pulley, and K equals the belt spring constant/unit strain in lbs./inch/inch. Thus, by lowering and raising the platform 3, F1 and F2 are varied as well as the belt spring constant.

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Flat Belt Drive Precision Speed Control Trimming Mechanism

This is a drive for magnetic disk 9. Synchronous motor 1 is mounted on platform 3 which is pivoted about axis 4. Screw 5, forcing against spring 6, is rotatable to move platform 3 and motor 1 up or down. Motor 1 drives shaft 2. Flat belt 7 connects shaft 2 and shaft 8 that rotates disk 9. When platform 3 is moved up and down, the tension in belt 7 is varied and this varies the belt creep.

The belt creep, inches/pulley revolution, is equal to 2 pi R (F1 - F2)/K. R equals the pulley radius, F1 equals the belt tension on the tight side of the pulley, F2 equals the belt tension of the slack side of the pulley, and K equals the belt spring constant/unit strain in lbs./inch/inch. Thus, by lowering and raising the platform 3, F1 and F2 are varied as well as the belt spring constant. As K increases in the equation, the creep decreases. The speed of the driven member increases as the creep decreases. Thus, the radius is chosen so that as the platform is lowered, the belt spring constant increases and the relationship of F1 - F2 is such that the creep decreases. In this way, the belt tension can be varied to enable the speed of shaft 8 to be set within very close limits.

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