belt system driven from the concentric fan motor to rotate the dryer drum in the embodiment of fig2 fig3 provides a side elevation view of an embodiment similar to that of fig2 differing in the means used to impart rotary motion directly to the drum in fig3 the fan motor 212 drives an output or fan drive shaft 228 and fan 226 with the shaft 228 having a drive belt pulley 229 thereon just as in the case of the equivalent components 112 128 126 and 129 of the embodiment of fig2 the pulley 229 in turn drives a jackshaft or drum drive shaft 234 by means of a jackshaft driven pulley 233 on one end of the shaft 234 just as in the embodiment of fig2 however rather than driving the drum 218 by means of a belt extending around the drum as shown in fig1 and 2 the jackshaft or drum drive shaft 234 has a friction wheel 236 rubber coated etc at its distal end which bears against a circumferential friction band 238 surrounding the dryer drum 218 rotation of the friction wheel 236 imparts rotational motion to the dryer drum 218 by means of the friction between the wheel 236 and friction band 238 around the drum it will be seen that such a drum drive system may also be incorporated in the embodiment of fig1 with the drum drive shaft 34 having a friction wheel 236 at the distal end thereof in lieu of the pulley 36 shown and the dryer 10 incorporating the drum 218 of fig3 with its friction band 238 fig4 provides an illustration of an additional embodiment of the present ambient air dryer in which.