CA2271019A1 - Transmission assembly - Google Patents

Abstract

The transmission assembly incorporates a mixer gearbox assembly, a system for centering and retaining a mixer shaft and drive and a seal. The mixer gearbox assembly is operable to drive a mixer shaft and is capable of receiving either a complete electric drive motor on a first face (15) of the gearbox housing (12) for operatively coupling with a first end of a long cross-shaft (22) in the housing, or alternatively a partial electric motor on a second face of the gearbox housing for operatively coupling with an opposite end (27) of the cross-shaft.

Description

TRANSMISSION ASSEMBLY
The present invention relater to apparatus for driving a mixer shaft, more particularly to gearbox apparatus for operatively connecting an electric motor to a mixer shaft, and most particularly to such gearbox apparatus wherein either of two types of electric motors can be connected alternatively at two different dedicated positions on a single gearbox.
Typically, a drive assembly for turning a mixer shaft uses a rugged cast housing containing a torque transmission including a train of gears mounted on one or more rotatable shafts, which train corn transmit torque from the output shaft of an electric motor mounted on the housing to a rotatable quill having an axial bore for receiving and retaining a mixer shaft. The quill may be equipped with and driven by an equatorial ring gear, also known as a bull gear, which is the ultimate gear in the gear train.
The shafts of the gear train may be oriented substantially parallel to the axes of the quill and mixer shaft, the motor being mounted on the top of the gearbox or housing. This layout (known as "vertical") results in a relatively tall drive assembly which can be unsuitable in locations having limited headroom over the mixer.
Alternatively, the shafts of tlhe gear train may be oriented substantially orthogonal to the axes of the quill and mixer shaft, permitting the motor to be mounted on a side of the housing and thus reducing the overall height of the drive assembly (known as "horizontal"), the bull gear and its drive pinion gear being bevel-cut gears. See, for example, U.S. Patent Nos. 4,198,373 and 5,501,117.
A horizontal drive assembly typically employs a complete electric motor. By "complete" is herein meant a rriotor having a pair of bearings supporting a drive shaft near or at opposite ends of the shaft within a motor housing, the motor being functionally independent of other apparatus for mechanical completeness.
The motor housing may have an integral flange at one end, by which it may be bolted directly to the gearbox or to a standoff from the gearbox, for example, a NEMA
C-face motor. Large motors may require instead or additionally a separate pedestal or foot for support to minimize or redistribute loads on the gearbox housing.
The SUBSTITUTE SHEE'~ (RULE 26) WO 98l22301 PCTiUS97120101

-2-motor shaft may be connected to the input shaft of the gear train by any conventional rotary coupling.
The just-described elements for conventionally connecting a standard motor to a gearbox add significant cost and weight to the mixer assembly.
neither of which is desirable. In a known alternate configuration, the coupling and standoff can be eliminated, along with one motor bearing and one shaft bearing, by providing a gearbox having a face specially configured to receive a partial motor.
A "partial" motor as used herein means a motor having only one shaft bearing at the distal end of the motor shaft and therefore being functionally dependent on mechanical elements of associated apparatus such as the gearbox. In this embodiment, the motor shaft is machined and bolted at its proximal end to mate and be integral with a pinion gear shaft in the gear train, the resulting integral shaft being supported by the distal motor shaft bearing and the pinion gear shaft bearing.
This alternate configuration, also known as an integral motor assembly. can reduce substantially the cost and weight of a mixer drive assembly. See, U.S. Patent No.

3,434,366 issued to Raso on March 25, l969 and Patent No. 4,811,616 issued to Henderson on March 14, l989.
Currently, the purchaser of a mixer drive assembly must choose between the complete-motor technology and the partial-motor technology because a partial-motor may not be substituted directly for a complete motor. For example, a purchaser having a large inventory of standard NEMA motors and spare parts may feel compelled to continue purchasing gearbox assemblies matable only with NEMA
motors, and thereby not avail himself of the benefits of the integral-motor configuration. On the other hand, a manufacturer choosing to purchase a new integral-motor assembly may then be committed to carrying an inventory of motors and parts for both configurations for at least an extended transition period, which can be expensive and hence undesirable.
Thus a need exists for an improved mixer gearbox assembly capable of accepting alternatively and with minimal modification either a complete electric motor or a partial electric motor.
It is a principal object of the invention to provide an improved mixer gearbox assembly wherein a single arrangement of shafts and gears may be driven SUBSTITUTE SHEET (RULE 26) alternatively by either a complete electric motor or a partial electric motor.
It is a further object of the invention to provide an improved mixer gearbox assembly wherein a cross-shaft extending substantially the full width of the housing thereof can mate alternatively with a complete motor drive shaft at one end thereof or with a partial motor drive shaft: at the other end thereof.
It is a still further object oi~ the invention to provide an improved mixer gearbox assembly having a housin~; capable of receiving alternatively a complete electric motor mounting flange ~on one face of the housing and a partial electric motor mounting flange on a different face of the housing.
It is a still further object oi' the invention to provide an improved mixer gearbox assembly wherein a motor having only one bearing in the motor housing is connected to a pinion gear shaft having only one bearing in the gearbox.
Briefly described, an improved mixer gearbox assembly in accordance with the invention contains a quill rotatably disposed in quill bearings in a gearcase or housing for receiving and driving a mixer shaft. The housing is provided with a first shaftway transverse of, and not intersecting, the quill, the first shaftway extending through first and second opposite walls of the housing. The f rst shaftway is provided with first and second bearing mounts within the housing and near the opposite walls, the mounts retaining at least one bearing for rotatably supporting a first cross-shaft having a first pinion gear mounted near an outboard end thereof, adjacent to the second wall of the housing. The housing is also provided with a second shaftway parallel with the first shaftway but intersecting the quill. The second shaftway is provided with bearing mounts for rotatably supporting a second cross-shaft. The second shaft is provided at its outer end with a gear drivingly engaged with the first pinion gear, and at its inner end with a bevel cut pinion gear drivingly engaged with an equatorial ring gear on the quill.
The transmission thus is able to drive the quill in double-reduction by the rotation of the first shaft. -The outer surface of the first housing wall surrounding a first end of the first shaftway is provided with features such as lands and threaded bores to permit mounting of a complete electric motor thereto, and the outer surface of a second and opposite housing wail surrounding the second end of the first shaftway SUBSTITUTE SHEET (RULE 26) WO 98l22301 PCT/US97/20101

-4-is provided with similar features to permit mounting of a partial electric motor thereto.
A long first cross-shaft is provided which is supported by first and second bearings in the housing and extends beyond both bearings. The first end of the shaft extends beyond the housing wall and is configured to be coupled to a standard motor shaft by, for example, a conventional shaft coupling. The opposite end of the cross-shaft is configured to be coupled to a partial motor shaft by, for example, a nesting cone or other known shaft joining and centering means. When a complete motor is coupled to the first end of the long cross-shaft, the opposite end where it extends beyond the bearings is covered by a first plate. Likewise, when the shaft is joined to a partial motor shaft, a cover is installed over the first end of the shaft. It is a feature of the invention that a cross-shaft in a mixer drive assembly can be connected alternatively to a complete motor drive shaft at a first end and to a partial motor drive shaft at the other end. It is a further feature of the invention that a single housing and gear train can accept alternatively a standard motor and a partial motor.
Alternatively, when the assembly is configured for partial-motor drive, a short first cross-shaft may be provided which extends inwardly of the housing through only one shaft bearing and outwardly through the second housing wall to mate directly with a partial motor, the covering plate having been omitted.
The first end of the shaftway, not occupied by a first cross-shaft and bearings in this configuration, is covered by a second cover or a plug. If the end use of the mixer assembly is to be only in combination with an integral partial motor, the assembly may be provided by the manufacturer with only the short first shaft configuration, thus saving the customer significant cost in shaft and bearings.
The foregoing and other objects, features, and advantages of the invention, as well as a presently preferred embodiment thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:
FIG. 1 is an elevational view, partially in cross-section, of a first configuration of a mixer drive assembly in accordance with the invention, showing a standard electric motor mounted via a stand-off to a first wall of the gearbox, the SUBSTITUTE SHEET (RULE 26) FEB. 5. l999 3: 30PM LAi;",,, PARRY NY 1 212 246 8959 ~ N0. 0g57 P. 5 _ _ PCTIUS~ 9 ~ ~ 2 0 i- ~
IPE~'~~ ~ ~ FEB i9~
-Sa-mounted on an unsupported, cantilevered portion df the shaft outboard of a bearing.
The opposite end 27 of shaft Z2 is configured to receive alternatively a partial motor shaft in a manner similar to that described for a short cross-shaft hereinbelow in reference to FIG. 2. 'fhe outer ends of shags 22 and 30, and gears 28 and 36, as shown in FIG. 1 are cowered by a plate 35 which is sealingly mounted on a second face 29 of housing 12 by bolts 37. Plate 35 forrns tin cad of the gearcase to retain lubricant therein.
A, shaft holder comprising a hollow quill 38 is rotatably disposed in upper and lower quill bearings 39 and 41) rcsgeytiyoly, within housiag 12, the axial orientation of the quill being substantially ortho~~onal to the axial, dircctioa of the ;... .. f rst end second cross-shafts. Quill 3 8 is provid,cd with a bevel-cut equatorial ring gear 40 which meshes in driving relationship with a bevel-eut pinion gear 42 mounted on the inner end of second cross-shaft' 30. Thus quill 38 is driveable in double gear reduction by motor 14 to turn miXf:r shaft 44 which is rigidly retained AMEPJGED SHEEP 02/05/99 FRI 15:28 1TX/RX NO 8258] B005 FE-B. 5. 1999 3 : 30PM L ~- ' S PARRY NY l 212 246 3959 N0, 0957 P. 6 ~CT/US v ;~ ~ ~ ~ ~. 0 tPEA/~10 ~ FEB 1999 eoaxially within the quill.
Referring to FIG. 2, a second mixer drive assembly 46 in accordance with the invention, provided with an integral partial motor I4') includes many elements identical with those in first assembly 1~D: housing 12, cross-shaft bearing 26, pinion gear 28, second cross-shaft 30 in bearings 32 and 34) drive gear 36) quill 3 8, equatorial gear 40, bevel-cut pinion gear 42, and mixer shaft 44. Opening 23 is sealingly closed by a pressed plug 48 to retain lubricant within the gearcase.
A
short first cross-shaft 22' disposed in fast shafhway 21 and supporting pinion gear 28 is jounnalled only in bearing 26, bearing 24 ;(in assembly 10) being omitted.
Plate 35 is also onnittcd, and in its place partial motor 14' having a case 49 and integral mouatilag flange 50 is mounted via bolts 37. Motor 14'' is said to be np~~n because it has only a distal bearing (ant shown in FIG. 2) for rotationally supporting only the distal esid of its motor shaft 20' and thus can be functional only when integrated with a second bearing element 26 in the gearbox Cross-shaft 22' is provided at the outer and with a male conical portion 54 which is received concentrically within a female conical portion 56 in the end of partial motor shaft 20'- Shaft 20' is provided with an axial bore 58 thmugh its entire length, and binder screw 60 therein is threadably received in a threaded axial bore 62 in the end of cross-shaft 22' to join shaft Z2' with shaft 20' as a single, colinear, rotatable unit without resort to a separate, distinct coupling, supported at opposite ends by the partial motor distal shaft bearing end gearbox bearing 26. Of course) other known r -_ shaft mating configurations exe oqually useful within the scope of the invention.
Second drive assembly 46 thus permits a signi~tcant lightening of the assembly over first assembly 10; reduction in manufacturing cost by the substitution of a short cross-shaft 22' for a long one 22, a~ad substitution of a partial motor 14' for a complete motor I4 with the elinnination of shaft bcarinE 24 and a pro~omal motor shaft baariag) plus a convention motor podestal and shaft coupling and substantial simplification over the alternative drive assembly I0) all within a common gearbox 12 and otherwise all the same drive elements as recitod above.
When only an integral partial motor is to be used with the mixer drive assembly, assembly 46 is the preferred embodiment.
Referring to FIGS. 3 sad 4) there is shown a mixer drive assembly 110 including a gearcasc or housing 1l2 supporting an electric motor 114 secured to the housing by standoff 116 and bolts 117. A coupling 118 connects motor shaft AMENDED SHEET 02/05/99 FRI 15:28 [TX/RX NO 6258I 1006 FE9. 5. l999 3: 31 PM Lt ; PARRY NY 1. 2l2 246 f3959 N0. 0957 P. 7 ' ~° -'~' ~2~1a ~u .~ ~ FEB 199 - 6a -120 coaxially with a f rst cross-shaft 122. Cross-shafts I22 is mounted for rotation in first and second cross-shaft bearings 124 and 126) respectively, and is provided near its end opposite motor 114 with a pinion gear (not visible in FIG. 3 ).
A) second cross-shaft 13 0 is mounted for rotation in indirect bearings 132 and 134, and is fitted at its outer end with a gear 136 which i:~ drivingly engaged by the pinion gear. "Indirect" refers to the gear being mounted on an unsupported, cantilevered portion of the shaft outboard of the bearings. A. shaft holder comprising a hollow quill 13 $ is roi$tably disposed in upper and lower quill bearings 139 and 141, respectively, within housing 1 I2, the axial orieaxation of the quill being substantially orthogonal to the axial direction of the fast and second cross-shafts.. Quill 138 is provided with an equatorial ring gear 140 whiclx meshes in driving relationship with ,._.
a bevel-cut pinion gear 142 nnounted on the inner end of second cross-shaft 139.
Thus quill l38 is driveable in double gear redwcfion by motor 114.
Tn accordance with the invention, quill 13$ is provided with an axial bore 143 having a first diameter 144 along a cemtral portion of the bore.
Diameter 144 is substantially identical with, or slightly smaller than, the outer diameter of mixer shaft 146 such that he unrestrained mixer shaft can slide freely within the quill bore 143. Preferably, shag 146 is rotatably connected co quill 13 8 via key 148 which is disposed in opposed keyways 150 and 152 in the shaft ,y d quill, respectively. Of course, other connections are possible, for -example, the shaft and quill can be splined together provided that the surfaces of the mixer shaft and quill bore 143 between the splines are smooth cylindrical surfaces.
The bore of quill 138 is provided with an upper tapered portion 154 and a lower tapered portion 156 near the uppcs cad lower entrances thereof, and i 60) respxtlvely) which portions preferably are unifoixnly tapered in iaereasi~ng diameter toward the entrances to provide prefi~ably conical locking surfaces.
The upper and lower taper 8ngles formed between the cylindrical central portion 143 and the tapered portion 154 and 156 may be the same or different. The portion 155 of the bore between locking surface 154 and the entranceway be conical or other shape such as cylindrical as shown.
Upper taper lock 162 and lower taper lock 164 are similar Rnd may be identical. Each has a cylindrical inner bore 166 which is only slightly larger is APAENCEC SHE=ET ~ ~ ~, ~ i 02/05/99 FR1 1S:28 (TX/RX NO 6258) Q007 . ._. , ,.,.. . . ., , . :. . ._ FE$. 5. l 999 3 : 31 PM LA"' S PARR Y NY 1 212 246 8959 PC7"/N0) 0957 P. 8 , ~5._:~W'2~10:
IPEI~'~~ 0 5 FEB 199 diameter than shaft diameter 144, e.g. 0.001 to 0a003 inch larger, permitting the lock to slide on the shaft when the Lock is unconstrained but to grip the shaft when radially compressed) Each lock has a tapered outer surface 168, preferably conical and preferably substantially identical with the taper of upper tapered portion and/or the taper of lower tapered portion 156 of the quill bore. Thus the angle of taper between the cylindrical bore 166 and the outer surface 168 is preferably identical with the angles of taper of portions 154 and 156 in the quill bore.
Preferably, the cylindrical inner bore 166 is relieved to a slightly larger diameter over a portion of the Lock beyond the axially ta~ored outer surface 1l>8 to control the location of wedging contact and the resulting. contact stress. ' Each taper lock also has circular equatorial flange 170 provided with a plurality of horns 172 to recai~o a plurality of mounting bolts 174 therethrough preferably three 120° apart. The upper Iock may ba slotted (not visible in FIGS. 3 and 4) to aceomrnodate key 148 during assembly.
. The upper end 176 of mixer shaft: 146 is provided with a transverse thrust plate Z 78 secured to the mtixer shaft by bolt 180 in an axial threaded bore 182. Thrust plate 178 is substantially the same diameter as, szad mates with, flange 170. Tightening of upper bolts 174 urges upper. lock 162 into centered and rigid relationship with upper tapered portion 154 the tapered portion o~the lock being slightly compressed to form essentially a swage fit between the shaft and the quill.
The lock my be loaded to any desired torque on upper bolts 174. Of worse, in some applications, flange 170 may be bolted directly to the quill to retain flue mixer .....
' shaft axially in the qu311 solely by the action of the taper lock, and tha tbzust~plate may be omitted.
Upper quill bearings I39 is retained axially in housing 1 t2 by a flange 177 oa quill 138. lower quill bearing 7141 is retained axially by a beating ratainer ring 184 threadably mounted in a step I85 on the outer surface 186 of quill 138_ An O-ring 187 in a groove is tha quill seals the threads against lubricant leakage from bearing 141. A conventional ring seal I91 runs against the outer surface 193 of rizxg 184 to prevent exchange o:f process fluids being mixed and bearing lubricant. The distance between flange 177 and step 185 is selected to provide a desired level of axial prcload vn the bearings when retainer ring 184 is AMENDED :3NEE.T
02/05/99 FRI 15:28 (TX/RX NO 82581 0008 FEB. -5. l999 3:31PM LAD'S PARRY NY 1 .2I2 24,6 8!5g PC N0, 0957 P, g S ~?20I0-I
IPEAI~~ (~ ~ F E B l999 _E~_ screwed down tight against step 185.
Retainer ring l84 surrounds shaft 146 the oper<ing therein being of sufficient diameter to accornrnodate the shaft and at least the tapered portion of (ewer taper lock 164. Ring 184 is pxovided with a plurality of threaded bolt holds 188 to receive lower mounting bolts 174 which also may be three bolts 120° apart.
Tightening of lower bolts 174 urges lower lock 1 ~64 into centered and rigid . relationship with lower tapered portion 156. The lower lock may be loaded to any desired torque oz1 lower bolts 174_ In the preferred embodiment) ring 184 thus performs , four functions: -a bearizig retainer; s thrust ring for the lower taper lock; an O-ring retainer;
and a sealing surfaca for a dynamic seal. Of course, Hnthin the scope of the invention, the - . bearings may be retained in some other way) such as by a snap ring, and the member presently defined as a threaded retainer ring can be simply the lower end of the quill into which flange 170 can be bolted diz~ectly.
The mixer shaft is readily removed from the quill by the removal of upper and lower mounting bolts 174, thrust plata3 178, and upper and lower Locks 162 and 164.
When assembled) the opposed upper and tower taper locks of the system rigidly and automatically retain the mixer sham in fixed, coaxial relationship with the quill, thereby preventing shaft runout or wobble and permitting the operation of the mixer at rotation frequencits at: or above the f rst critical frequency of the mixer.
From the foregoing description i1; will be apparent that there has been provided an improved systeut for mounting a 9laeft in a shaft holder, and particularly a mixer shaft in a quill wherein spaced-apart and opposed upper and lower taper locks secure the shaft in rigid, centered relationship within the shaft .holder, or quill.
Referring to FIGS. 5 through 8 where is shown a mixer drive assembly 210 for transmitting torque via gear reduction from an electric motor to a mixer shaft. Assembly 210 includes a gearbox or housing 212 supporting a conventional electric motor 214, for example, a NEMA C-face motor. Housing 212 is preferably a ductile ixon casting having a hardness of about l50 Brinell.
Housing 212 rotatably supports a gear train comprising a first cross-shaft 216 connected via . AMENDED SHEET , ~ , , .
02/05/99 FRI 15:28 [TX/RX NO 6258] D 009 FEB. 5.1999 3:45PM LAL~~ PARRY NY 1 2l2 246 8959 N0.095? P. 10 .
. i i .' _ . _ 1PE~/~,~~~ ~ FEB 1999 coupling 218 to motor shaft 22d; a pinion gear :! 22 on first shaft 216; a rotatably mounted second cross-shaft 224 supporting a dcwice gear 226 meshing with pinion gear 222 and a bevel-cut pinion gear 228 meshing with a bevel-cut ring gear oquatorially disposed on quill 132. Quill 132 is rotatably mounted in upper and lower quill bearings 234 and 236, respectively. A mixer shaft 238 is rigidly centered and retained within quill 232. Housing; 212 is closed by a sealed top cover 240 and a scaled end plate 242 and is substantie~lly or nearly filed with oil lubricant 244 so that all the rotating and meshing components just enumerated, except for the quill bearings 234 and 236, arc bafihcd in oil during operation of the mixer drive assembly.
Quill bearings 234 and 236 are pracked with high viscosity grease and ,, preferably have an airspace 246 therebetween the combination of bearings and airspace being known as a "dry well". Upper bearings 234 is supported in a bearing mount 248 in housing 212 having a strop 250 which governs the axial location of the bearings 234. Bearing 234 includes an. outer rice 252 and an inner race 254) the outer race being stationary and sealingly dispo:;ed in bearing mount 248, and he inner race being sealingly mounted on end turx~able with quill 232. Bearing mount 248 is provided with a planar axial upper surface 249 which is one of the sealiuag elements of a seal in accordance with the inveaation. ._ Inner race 254 is Locatod axially by a step 256 in he quill. Beriveea race 254 and step 256 is captured a labyrinth :;eal element 258 baring a generally circular element formed) for example) by punching from a sheet of steel stock p~roferably about 0.030 inch thick. Mild hardxiess steel is presently preferred_ Seal element 258 has a central aperture 260 substantially the same as the ianar diamater of face 254 so that both can be slid along the quill from the lower end into proper location shown in FIGS. 7 and 8. Element 2:i8 further has a peripheral flange extending snbst$ntially axially to and orthogonally From the radial portion thereof. The depth 264 of step 250 from scaling surface 249 is selected so that upon assembly of the quilt and beings in the lousing the lower end 266 of flange 261 interferes with surface 249 and element 258 bcwmes dished by betwean about 0.003 inch and 0.050 inch.) preferably about 0.010 inch, as shown in FIG. 7.
The peripheral flange is thus urged against the sealing surface under a pre-load.
A(vIEND~O SHth~~f r r .r;~ ~ .~ ~ r .. .r 02/05/99 FRI Z5:43 [TX/RX NO 8259] B001 FEB. 5. l999 3:45P1, ' L~DAS PARRY NY 1 212 246 8959 P 95 P. 1 CT~~ ~7;'~Oi:
~PEA/~~ 0 5 FEB 19'.
- 6e -When the mixer beings operation, the pre-loaded hardened steel flange beings to wear a groove 263 exactly the size of the flange into the cast ductile iron of surface 249. As it does so the pre-load is gradually diminished until at equilibrium the lower end of 266 extends into a mating groove on surface 249, forming an interference-fit labyrinth seal. The seal is formed automatically and inexpensively by the cutting action of the flange on the surface. A perfect fit of the groove to the flange is obtained simply and without resort to costly precision matching of these parts. Since the flange is selected to be harder than the surface 249, further running of the mixer produces no lirither wear of either seal component and no significant degradation in the effectiyene:ss of the seal.
f, _,,, Only a single labyrinth is shoran in this preferred embodiment) but multiple labyrinths can be provided as desired vvithin the scope of the invention by providing additional concentric flanges extending within flange 261 from the underside of clemeztt 258. T'he annular cavity defined by the element 258 and the surface 249 and the bearing 234 may be filled vvith grease to further enhance the seal. The step at the upper end of the bearing f.34 also presents a barrier and provides a seal effect.
In the preferred embodiment) the flange is ro~table and the sealing surface is stationary. Other configurations in other applications ego possible, of . course, for example, the flange may be stationary and the sealing surface rotatable;
and the flange may be provided on the boring mount, and aua appropriaxe seali~ag . ~~ pro~~ on the quill.
From the foregoing description it will be apparent that there has been provided an improved dynamic shaft seal wherein a durable seal element is pre-leaded to run against a softer sealing surFace and thereby to wear an iaderferenee-fit labyrinth coal groove in the softy material. Variiations and modifications of the herein described labyrinth seal.
AMENDED SHEET
02/05/99 FRI 1S:43 ['TX/RX NO 82591 _002

Claims (19)

1. A double taper lock system for coaxially centering and retaining a mixer shaft disposed in a mixer drive quill, comprising:
a) the quill having an axial bore receivable of the mixer shaft, said bore including a central cylindrical portion having a first diameter and a first portion tapering in increasing diameter from said central portion toward and end of said bore and a second portion tapering in increasing diameter from said central portion toward the opposite end of said bore;
b) a first taper lock having a cylindrical bore receivable of the mixer shaft and an outer surface concentric with said bore and tapered in diameter in an axial direction to define a first tapered surface substantially identical with said first tapered portion in said quill;
c) a second taper lock having a cylindrical bore receivable of the mixer shaft and an outer surface concentric with said bore and tapered in diameter in an axial direction to define a second tapered surface substantially identical with said second tapered portion in said quill, at lead one of said first and second taper locks including a circular flange extending radially over at least a portion of one of said ends of said quill bore, and at least one of said first and second taper locks extending beyond the corresponding end of said quill bore;
d) first means reactive against said quill for urging said first taper lock toward said second taper lock; and e) second means reactive against said quill for urging said second taper lock toward said first taper lock, at least one of said first and second means for urging including a removable ring attachable to an end of said quill, said ring and said circular flange on said taper lock having a plurality of matching bores for receiving bolts, the ring bores being threaded, the flange and ring being spaced apart, and the tightening of said bolts urging said taper lock through said ring into said quill bore.

2. The system in accordance with claim 1, wherein said removable ring is a quill bearing retainer.

3. The system in accordance with claim 1, further comprising a key disposed in a keyway in said quill bore.

4. The system in accordance with claim 1, wherein said first tapered portion in said quill bore is conical.

5. The system in accordance with claim 1, wherein said second tapered portion in said quill bore is conical.

6. The system in accordance with claim 1, wherein said first tapered outer surface of said first taper lock is conical.

7. The system in accordance with claim 1, wherein said second tapered outer surface of said second taper lock is conical.

8. The system in accordance with claim 1, wherein the angle of taper of said first tapered portion in said quill bore is substantially the same as the angle of taper of said outer surface of said first taper lock.

9. The system in accordance with claim 1, wherein the angle of taper of said second tapered portion in said quill bore is substantially the same as the angle of taper of said outer surface of said second taper lock.

10. The system in accordance with claim 1, wherein at least one of said first and second means for urging comprises a transverse plate outboard of and in contact with one of said first and second taper locks, and a plurality of bolts extending through said plate and into matching bores in said quill, tightening of said bolts causing said plate to urge said taper lock into said quill bore.

11. A self forming labyrinth seal for preventing leakage of fluids along a rotatable shaft in a stationary housing, the shaft being supported by bearings in races disposed in the housing, comprising:
a) a first sealing element having an axially-directed circular face on a surface of said housing radially extensive beyond said bearing races said first element having a first hardness; and b) a second sealing element disposed for rotation with said shaft and having a radially-directed portion supporting a cylindrical axially-directed portion in contact with said circular face on said first sealing element, said radially-directed portion being axially-deformable to define a spring to urge said cylindrical portion against said circular face, said cylindrical portion having a second hardness, and said second hardness being greater than said first hardness.

12. A seal in accordance with claim 11, wherein said housing is a housing for a mixer drive gearcase.

13. A seal in accordance with claim 11, wherein said spring deformation is between about 0.003 inches and 0.050 inches.

14. A seal in accordance with claim 11, wherein said bearings include a drywell airspace, and wherein said seal is disposed between said fluids and said drywell airspace to prevent the ingress of fluids to, and the escape of air from said bearings.

15. A method for forming a labyrinth seal for preventing leakage of fluids along a rotatable shaft in a stationary housing, the shaft being supported by bearings in races disposed in the housing, comprising the steps of:
a) providing a first sealing element having an axially-directed circular face on a surface of said housing radially extensive beyond said bearing races, said first element having a first hardness;
b) providing a second sealing element disposed for rotation with said shaft and having a radially-directed portion supporting a cylindrical axially-directed portion in initial contact along its lower edge with said circular face on said first sealing element, said cylindrical portion having a second hardness, and said second hardness being greater than said first hardness;
c) axially deforming said radially-directed portion to define a spring to urge said cylindrical portion against said circular face; and d) rotating said shaft to cause scud cylindrical portion to incise and occupy an interference-fit mating groove in said housing face, said cylindrical portion and said mating groove thereafter defining a labyrinth seal.

16. A mixer gearbox assembly for driving a mixer shaft, comprising:
a) a housing configured to mountingly receive, alternatively, a complete electric motor on a first face thereof or a partial electric motor on a second face thereof;
b) a first cross-shaft disposed in a first shaftway in said housing, said shaftway extending between said first face and said second face, said first cross-shaft having a first end configured to mate with a drive shaft of a complete electric drive motor and a second and opposite end configured to mate with a drive shaft of a partial electric motor;

c) a first pinion gear disposed on said first cross-shaft;
d) a second cross-shaft disposed in said housing;
e) a first drive gear disposed on said second cross-shaft in meshing relationship with said first pinion gear;
f) a quill rotatably disposed in said housing, for retaining and turning a mixer shaft;
g) a quill gear disposed on said quill; and h) a second pinion gear disposed on said second cross-shaft in meshing relationship with said quill gear.

17. A mixer gearbox assembly for diving a mixer shaft, comprising:
a) a housing configured to mountingly receive, alternatively, a complete electric motor on a first face thereof or a partial electric motor on a second face thereof;
b) a first cross-shaft disposed in a first shaftway in said housing, said shaftway extending between said first face and said second face, wherein said first cross-shaft is rotatably mounted in a single bearing within said housing;
c) a fist pinion gear disposed on said first cross-shaft;
d) a second cross-shaft disposed in said housing;
e) a first drive gear disposed on said second cross-shaft in meshing relationship with said first pinion gear;
f) a quill rotatably disposed in said housing, for retaining and turning a mixer shaft;
g) a quill gear disposed on said quill; and h) a second pinion gear disposed on said second cross-shaft in meshing relationship with said quill gear.

18. A mixer gearbox assembly for driving a mixer shaft, comprising:
a) a housing configured to mountingly receive, alternatively, a complete electric motor on a first face thereof or a partial electric motor on a second face thereof;
b) a first cross-shaft disposed in a first shaftway in said housing, said shaftway extending between said first face and said second face;
c) a first pinion, gear disposed on said first cross-shaft;

d) a second cross-shaft disposed in said housing;
e) a first drive gear disposed on said second cross-shaft in meshing relationship with said first pinion gear;
f) a quill rotatably disposed in said housing, for retaining and turning a mixer shaft;
g) a quill gear disposed on said quill; and h) a second pinion gear disposed on said second cross-shaft in meshing relationship with said quill gear, wherein said housing can receive, alternatively, a first cross-shaft rotatably mounted in said first shaftway in first and second spaced-apart shaft bearings and a first cross-shaft rotatably mounted in said first shaftway in a single shaft bearing.

19. A mixer gearbox assembly for driving a mixer shaft, comprising:
a) a housing configured to mountingly received, alternatively, a complete electric motor on a first face thereof or a partial electric motor on a second face thereof;
b) a first cross-shaft disposed in a first shaftway in said housing, said shaftway extending between said first face and said second face, said first cross-shaft being provided with a mating portion at an end thereof, which portion is matable with a motor shaft of said partial electric motor;
c) a first pinion gear disposed on said first cross-shaft;
d) a second cross-shaft disposed in said housing;
e) a first drive gear disposed on said second cross-shaft in meshing relationship with said first pinion gear;
f) a quill rotatably disposed in said housing, for retaining and turning a mixer shaft;
g) a quill gear disposed on said quill; and h) a second pinion gear disposed on said second cross-shaft in meshing relationship with said quill gear.