Abstract: A conveyor drive having a first crank (44) rotatably mounted to a base (24) for producing a first sinusoidal harmonic and a second crank (62) rotatably mounted to a conveying trough (22) for producing a second sinusoidal harmonic. A link (66) is connected between the first and second cranks (44, 62) to impart a first sinusoidal harmonic of the first crank (44) to the second crank (62). The second crank imparts a working displacement to the conveying trough (24) as a function of a phase relationship between the first and second sinusoidal harmonics of the respective eccentrics (44, 62). A synchronizer (FIG. 5) is operatively connected to the cranks (44, 62) for selectively adjusting the angular phase relationship between the first and second sinusoidal harmonics of the respective cranks (44, 62) to correspondingly vary the working displacement imparted to the trough (22), thereby controlling the speed of material being conveyed along the trough (22).

Abstract: A drawdown hopper isolation system having a series of isolators supporting the hopper in spaced relation from a support surface. Each of the isolators is comprised, in preferred form, of a rubber block having an axial bore therethrough, a series of parallel nylon fabric lays being axially spaced one from another within the block. The nylon fabric lays are rotationally oriented in random fashion, relative to the axis of the block, so as to insure relatively even lateral deflection of the isolator in response to vibration of the hopper. A stud fixed to the hopper extends into one end of the isolator's bore, and a stud fixed to the hopper support surface extends into the other end of the isolator's bore, thereby locating the hopper in a desired position on the support surface.