General Signal Corporation

Other

Joel S Berg

Stephen L Markle

David J Engel

Marlin D Schutte

William F Hutchings

William J Hutchings

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. The alternative configuration can reduce the cost of manufacture of the gearbox assembly through elimination of a motor bearing, a shaft bearing, and a long cross-shaft, and also this configuration eliminates the usual motor pedestal and its coupling, and through use of all other parts identical with those of the alternative-motor assembly.

Mixer gearbox assembly having a cross-shaft alternatively mounted in one

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. At the lower end of the quill, a bearing retainer ring threaded onto the outer surface of the quill is bored to receive bolts extending through a flange on the lower lock to press the lower lock into locking relationship. The rigidity of the lock increases the first critical frequency of the mixer system and therefore permits operation at high speeds, including rotational frequencies greater than the first critical (natural) frequency of the mixer system.

Double taper lock system for a locking a mixer shaft in a quill

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. The axial positions of the outer bearing race mount on the housing and the disc-shaped seal element on the quill are selected so that, upon assembly of the bearings and seal, the lower edge of the flange interferes with the circular surface causing the disc-shaped seal element to be elastically deformed to define a dish-shaped spring having a depth of 0.010 inch. Upon rotation of the quill, the flange is urged by the pre-load of the spring to incise and then occupy an interference-fit groove in the circular surface, thereby forming an inexpensive, and effective labyrinth seal against leakage of gear lubricant through the quill bearing.

Self-formed labyrinth seal

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. Then the jack screw is rotated to drive the mixer shaft assembly axially from the quill bore. When the mixer shaft is free of the seal assembly, the shaft is secured to the vessel wall. The quill shaft is disconnected from the mixer shaft, and the jack screw is counter-rotated to withdraw the quill shaft from the seal assembly, permitting the seal assembly to be removed in a radial direction from the mixer assembly.

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Hilton, NY, United States of America

Joel S Berg