GB913974A - Multiple-speed chart drive for a recorder - Google Patents

Abstract

913,974. Change-speed gear. LEEDS & NORTHRUP CO. March 21, 1961 [April 28, 1960], No. 10320/61. Class 80 (2). The drive-shaft 17 for a recorder chart roll 12 is rotated by an electric motor 15 at high speed through a shaft 16, spring coil clutch 22 and worm gearing 20, 21, or at low speed through a reduction gear train 30, 32, 33, 34, a second coil clutch 38 and worm gearing 31, 35, the clutches 38, 22 over-running during high and low speed conditions, respectively. Speed control is exercized by a bell-crank lever 50, manually or solenoid-operated, and engageable with a notched wheel 28 controlling the spring of clutch 22. For high speed, lever 50 is disengaged to allow the spring to be operative, the high speed of shaft 17 causing overrunning of clutch 38, while for low speed, lever 50 is engaged with wheel 28 to unwind the spring of clutch 22, permitting worm wheel 20 to rotate freely on shaft 16, while clutch 38 becomes effective to drive shaft 17. In a modification, Figs. 4 and 5 (not shown), a double clutch assembly 22 is provided whereby the reduction train remains stationary under high speed drive conditions.