Abstract: A mixer gearbox assembly for driving a mixer shaft capable of receiving either a complete electric drive motor on a first face of the gearbox housing for operatively coupling with a first end of a long cross-shaft in the housing, or alternatively a partial electric drive motor on a second face of the gearbox housing for operatively coupling with an opposite end of the cross-shaft. In an alternative configuration for use with only a partial motor, an assembly containing otherwise identical components is provided with a short cross-shaft replacing the long cross-shaft, which short shaft is supported by a single bearing and is colinearly matable only at the outer end thereof with the drive shaft of a partial electric motor. The rotor and short shaft act as a unitary structure when assembled.

Abstract: A system for automatically centering and rigidly retaining a mixer shaft in a mixer drive. A hollow quill in a mixer drive is provided with an axial bore having a first diameter along a central portion thereof and tapering linearly and axially in opposite directions away from the central portion with increasing diameter to define a pair of opposed conical portions of the axial bore on either side of the central bore. A smooth-surface cylindrical mixer shaft inserted into the bore is retained by the tightening of upper and lower tapered cylindrical locks which are slidable along the mixer shaft and have conical outer surfaces which are matable with the upper and lower conical portions of the quill bore. The locks, when urged into wedged relationship between the shaft and the quill bore, automatically center the shaft in the quill in rigid retention. The upper end of the shaft is provided with a thrust plate secured by throughbolts into the quill to press the upper lock into locking relationship.

Abstract: A labyrinth shaft seal for preventing the migration of gear lubricant from a mixer drive assembly into a batch of process materials being mixed. In the preferred embodiment, a portion of the gearcase outboard of the upper quill bearing, preferably the actual bearing mount, is provided with an axially-directed circular face, the mount being formed of relatively soft material such as ductile cast iron. A disc-shaped seal element having a central aperture and supporting an axially-directed peripheral cylindrical flange is sealingly mounted on the quill above the quill bearing and extends radially from the quill and generally parallel to the circular face. The flange is formed of material substantially harder than the circular face.

Abstract: A mixer assembly including a driven hollow quill having first and second conical portions in an axial bore and being adapted to receive and mate with a mixer shaft assembly including a mixer shaft having a conical chamfer to mate with the first conical portion and a quill shaft disposed on and removable from the end of the mixer shaft. The quill shaft has a threaded aperture which cooperates with a jack screw rotatably mounted within the quill bore to draw the conical chamfer into preloaded centered relationship with the first conical portion of the quill bore. A tapered sleeve lodged between the mixer shaft and the second conical portion of the quill bore distributes radial loads on the shaft over a large area of the quill, thereby preventing damage to the shaft and quill. A seal assembly on the mixer shaft isolates the housing from the interior of the vessel. The seal is readily removed for replacement. First, the tapered sleeve is released from the second conical portion.