Small motor for pen recorder - has rotor driven by opposed tangential air jets

摘要

A pneumatically driven motor for a pen recorder has a hollow drive shaft mounted on ball bearings (19). The rotor (11) comprises a pair of essentially circular plates sealed at the edges and defining an enclosed air space (12). Lateral holes in the drive shaft communicate with this air space. Motive force is provided by air emitted by way of tangentially directed holes (14) at the rotor edge passing to notches cut in the disc periphery. The drive shaft has a notched end (21) on which is mounted a reduction gear which provides a reduction of 6000:1.