US2551980A - Driving mechanism for centrifugal separators - Google Patents

Description

DRIVING MECHANISM FOR CENTRIFUGAL SEPARATORS Filed Feb. 5, 1946 '4 Sheets-Sheet l J- E. THOLL.

DRIVING MECHANISM FOR CENTRIFUGAL SEPARATORS Filed Feb. 5, 1.946

4 Sheet s 2 w HQSH DRIVING MECHANISM FOR CENTRIFUGAL SEPARATORS Filed Feb. 5, 1946 4 Sheets-Sheet 4 Patented May 8, 1951 UNITED STATES TENT OFFICE DRIVING MECHANISM FOR CENTRIFUGAL SEPARATORS Application February 5, 1946, Serial No. 645,519

Claims.

In my earlier Patent No. 2,112,430, granted March 29, 1938, I have described and claimed a two-speed drive for centrifugal separators of the type much used in sugar refiners and for other purposes where it is highly desirable to drive the basket at a high speed during the centrifuging operation, and then to operate it at a very slow and uniform speed during unloading or discharging. This mechanism has proved exceptionally satisfactory and has enjoyed a Wide acceptance in the trade.

The present invention aims further to improve and to perfect the mechanism disclosed in said patent with a view to reducing the rate of Wear created in the parts of said mechanism; reducing the care and attention required by it; and generally increasing its serviceability.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Fig. 1 is a side elevation of a mechanism con structed in accordance with this invention;

Fig. 2 is a plan view of the mechanism shown in Fig. 1, with some parts shown in horizontal section;

Fig; 3 is a sectional view on the line 3-3, Fig. 2;

Fig. 4 is a partial horizontal section taken substantially on the line 44 of Fig. 3;

Fig. 5 is a half-sectional view showin a modified embodiment of the invention; and

Fig. 6 is a vertical, sectional view showing on a larger scale portions of the clutch illustrated in Fig. 3.

Referring first to Figs. 1 to 4, inclusive, the construction there shown illustrates the invention as applied to a suspended type of centrifugal, the basket being indicated in Fig. 1 at 2, supported, on a vertical shaft 3, which may either be a continuation of the shaft 4 of the main driving motor 5, or may be an integral part of that shaft.

In any event, the basket shaft and the motor shaft are connected together to revolve in unison so that they function as a single shaft.

For the purpose of driving the basket at a slow speed, during the discharging operation, a much smaller supplemental motor 6, Figs. 1 and 2, is provided and it isv connected with the shaft 4 through a gear reduction mechanism comprising a worm 1, Figs. 2 and 3, fast on the shaft 6 of the supplemental motor and meshing with; a worm wheel 8. This drive takes place through an overrunning clutch comprising an outer sleeve 10, Figs. 3 and 4, and an inner sleeve II. The former is bolted to the upper end of a cup-shaped coupling [2 which is secured to the upper end of the motor shaft i, while the latter is keyed to a stub shaft l3 integral with the central hub member 8 of the worm gear 8. Thus the outer and inner clutch sleeves l0 and I l are connected positively with their respective motors 5 and 6 to be driven thereby.

Interposed between these two clutch sleeves are several power-transmittin cams l5 shaped approximately as shown in Fig. 4. Each cam is an elongated flat-sided bar and its inner edge is provided with a rib a resting loosely in a groove formed in the periphery of the sleeve I i, while its outer edge is of cam formation, the distance between the rib a and the two corners b and c of the cam shown in the center of said figure differing quite substantially. Also, the outer edge surface of the cam 15 between the corners b and c has a rounded eccentric form. From the opposite ends of each of these cam members two pins e project and bear normally against the inner surfaces of two flanged collars dd which are carried by the inner sleeve II, as best shown in Fig. 6. They prevent any substantial radial movement of the cams outwardly. Also, light springs, one of which is shown at IS in Fig. 4, act on the respective pins 6 to give the cams a slight initial bias backwardly with reference to their direction of rotation. A washer !9, Fig. 6, is secured by a screw l9 to the lower end of the shaft l3 where it supports the lower end of the inner sleeve H and cooperates with another part of the stub shaft engaging the upper end of said sleeve to hold it in the proper axial position in the mechanism.

Assuming that the small motor 6 is driving the inner sleeve il in the direction indicated by the arrow in Fig. 4, and that the outer sleeve It is stationary, or is revolving in th same direction at a slower speed than the inner sleeve, then each a cam IE will be tipped in a clockwise direction, thus bringing the radially higher part of each cam into contact with the inner surface of the sleeve Hi and causing all the cams in the series to jam between the two sleeves and thus to pick up the outer sleeve in rotation with the inner one. At this time, therefore, the motor 5 will drive the basket shaft 3 through the sleeves Ill and H and the cams l5. The speed of rotation will be slow because of the gear reduction mechanism through which the drive is effected.

I If, now, the control switch of the main motor should be closed and the latter motor started into rotation, thus revolving the outer sleeve ill at a higher speed than the inner sleeve, then the contact of the inner surface of the outer sleeve with the cams [5 will tip them in a counterclockwise direction and thus interrupt the connections through which the small motor has been driving the outer sleeve. If, also, the power is shut off the supplemental motor, all of the clutch parts, except the outer sleeve ID, will stop and remain stationary. Later, when the power is cut off the main motor 5 and is turned on to the supplemental motor ii, the cams i5 will again operate automatically to shift the drive for the shaft 4 back again to the inner sleeve ii. In other words, the action of these cams in the clutch is to shift the drive automatically to the sleeve revolving at the higher speed.

When the cams !5 are stationary they do not bear against the inner surface of the outer sleeve with sufficient pressure to create any substantial degree of wear, and such wear is further reduced by the lubrication of said inner surface and of the cams themselves. Because the cams are non-rotating, they cannot be revolved around their own axes, as would be the case if they were rolls.

This arrangement, therefore, contributes materially to the reliability and length of life of the driving mechanism, reducing maintenance, both in cost of parts and in the labor involved.

The motor 5 is equipped with bearings supporting its shaft i for rotation around a fixed axis, and the clutch sleeves l0 and l l are spaced apart by upper and lower ball bearings ll and i8, respectively, which support the outer sleeve for rotation around the same axis. In addition, the hub member 8 of the worm gear 8 is provided with an upwardly extending stub shaft section 8" which also is supported by a set of ball bearings mounted in the casing or housing 2| that encloses the entire clutch mechanism and the driving elements above referred to. In the particular arrangement shown this casing 2i and the end section of the casing for the motor 6, are cast as an integral piece, thus providing a firm, rigid support for the running parts.

A further feature of this invention resides in a novel lubricating system so organized as to feed oil automatically to all of the friction surfaces of this mechanism. Referring again to Fig. 3, it will be observed that an oil well 22 is provided in the lower part of the casing 2|, and a port leads from the bottom of this well directly into a pump 23, Figs. 1 and 3, which is secured to the side of the casing. Mounted in this pump assembly is a plunger 24 extending radially inward with its inner end bearing against the outer eccentric surface 1 of the upper part of the coupling member [2. This member is always in rotation when the mechanism is in operation, and it is so designed as to cooperate with a concealed spring acting on the plunger to impart a short reciprocating stroke to it. Cooperating with this plunger are upper and lower valves (not shown) as are common in a plunger pump construction to force oil taken from the well 22 up through the pump and the discharge ducts 25 and 26 formed in the casing 2| and in the casing cap 2 I" into the transparent sight glass 2'! at the top of the cap. The oil so delivered overflows into the top of a nipple g in said cap and runs down through the bore of said nipple into an oil distributing chamber or reservoir 28, the bottom of which is clos by the thimble 28'.

From this receptacle oil flows through a central discharge aperture in the thimble 28 into a bore h in the hub 8 and then downwardly through said bore and through a connecting radial duct into and through the upper ball bearing ll. It continues downwardly along the inner surface of the clutch sleeve it, through the lower ball bearing 18, and is discharged by centrifugal action through ports 7c into the oil well 22. Preferably the bottom of this oil well is inclined toward the left, Fig. 3, so as to drain the oil toward the inlet to the pump 23.

Some of the oil delivered to the chamber 28 flows through an aperture in into the upper ball bearing 29 and is then caught in a cup 11. from which a spout 38 conducts it to the worm i. The housing for this worm is shaped to provide a trough 3! which retains some oil continuously in contact with the lower surface of the worm, the

1 surplus overflowing the inner edge of the trough into the oil well 22.

The caps 2| and T, Fig. 2, are removable to permit access to, and inspection of, the enclosed parts, and a plug 32, Fig. 3, is provided in the cap 2 l for this purpose.

With this arrangement exceptionally good lubrication of all of the friction surfaces is maintained without attention on the part of the workmen, except to see that an ample oil supply is maintained in the well. Preferably an oil seal 33, 3, is provided in the shank of the coupling l2 to close the joint between this member and the motor shaft 4.

In the construction above described. the main motor 5 has been mounted below the clutch mechanism. In some cases, however, it is preferable to arrange these parts in a reverse relationship. Such a construction is shown in Fig. 5 in which the parts corresponding to those above described are designated by the same, but primed, numerals. The motor 5 is mounted above the clutch and its shaft 4 extends downwardly through the clutch mechanism and through the brake drum 3%, fast on it, into the suspension head 35 at or below which it is coupled to the basket shaft 3'. Upper and lower ball bearings 36 and 3?, respectively, support this shaft and are themselves supported in the machine frame 38 which, in this embodiment of the invention, forms the casing for the driving and clutch mechanisms. In the clutch the sleeve H is loose on the shaft i but is secured to the hub of the worm gear 8 so that it rotates therewith.

Thus it approximately takes the place of the stub shaft [3 and the sleeve H of the construction above described. Consequently, the operation of this mechanism is exactly like that disclosed in connection with Figs. 1 to 4, inclusive, the same clutch mechanism being included in this modification.

A similar lubricating system also is provided comprising the pump 23 discharging through an outside pipe connection ii] into the sight glass 21. From this glass the oil flows through a lateral pipe ll into a shallow annular receptacle or chamber 42 from which an oil duct 43 leads lubricant into the uppermost ball bearing 36. From there it flows by gravity through ducts o in the hub of the worm gear down into and through the two ball bearings of the clutch, lubricates the inner surface of the sleeve i0, and is discharged through outlets it into the oil well 22'. Another tube i leads oil from the chamber 42 to the surface of the worm 2" with which a trough 3! also i associated, as in the construction above described. Any oil overflowing the walls of the annular chamber 42 isconducted back into. the oil well through the duct 55. A similar provision is made for taking care of overflow from the oil chamber 28, shown in Fig 3, where the duct 29 carries off the surplus and leads it back into such a position that it ultimately flows into the oil well.

Because the plungers for both the pumps 23 and 23 should have lubrication, I prefer to drill a small hole axially through each plunger for its entire length so that upon each inward stroke a little oil will be forced backward through the plunger and discharged against the eccentric surfaces and which operate it.

The foregoing features materially improve the construction shown in my earlier patent, by reducing the rate of Wear inthe driving mechanism, both because of the changes in organization of this mechanism and also because of the provision made for automatically lubricating all of the friction surfaces. This, in turn, results in reducing the care and attention required by the workman, eliminating much of the necessity for repair parts, and correspondingly reducing maintenance costs,

While I have herein shown and described preferred embodiments of myin-v-ention, it will be evident that the invention may be embodied in other forms without departing from th spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

1. The combination with a centrifugal separator including a basket shaft and a, basket fixed thereon, of a main electric motor directly connected with the basket shaft to revolve the basket at normal speeds, a low speed driving shaft supported adjacent to one end of the basket shaft, a clutch comprising inner and outer sleeves concentric with each other and with said basket shaft and low speed driving shaft said inner sleeve being secured to the low speed driving shaft, a series of pivotally supported elongated cams parallel with said low speed driving shaft and interposed between said sleeves, means securing said outer sleeve to said shaft for rotation therewith, a normally idle supplemental motor of smaller horse power than said main motor, a reduction gearing through which said supplemental motor is connected in driving relationship with the low speed shaft, said supplemental motor in operation being adapted to drive the basket shaft through the said clutch when the main electric motor is not running, said reduction gearing connections holding said sleeve substantially stationary when said supplemental motor is not running, means supporting said cams on said inner sleeve for rotation substantially in unison therewith but against rotation when the inner sleeve is stationary, said cams being shaped to jam against, and make a driving engagement with, the outer sleeve when the inner sleeve revolves faster than said outer sleeve and to release the latter sleeve automatically when it revolves faster than the inner sleeve, whereby said inner sleeve and said cams remain substantially stationary when said shaft is driven through said outer sleeve by said main motor.

2. A combination according to preceding claim 1, including a casing in which said clutch, said reduction-gearing and a part, at least, of said shaft are enclosed, said casing including an oil well, a pump driven by a part connected with said outer sleeve and revolving with it, an oil receptacle located above said reduction gearing and said clutch, connections for conducting'oil from said pump into said receptacle, and means for conducting oil from said receptacle by gravity to the various friction surfaces of said reduction gearing and said clutch.

3. The combination with a centrifugal separator including a basket shaft and a basket fixed thereon, of a main electric motor directly connected with the basket shaft to revolve the basket at normal speeds, a low speed driving shaft, means for supporting the low speed shaft in fixed axial alignment with the said basket shaft, a normally idle supplemental motor of smaller horse power than said main motor, a clutch for operatively connecting the basket shaft and main electric motor with the low speed driving shaft, said clutch comprising inner and outer sleeves concentric with each other and with said basket shaft and low speed driving shaft, a series of pivotally supported cams interposed between the said sleeves, means securing said outer sleeve to the basket shaft, a reduction gearing through which said supplemental motor is connected with the inner sleeve, said reduction gearing consisting of a worm and worm wheel fixed to the low speed driving shaft, said connections holding said inner sleeve substantially stationary when said supplemental motor is not running, means supporting said cams on said inner sleeve for rota tion substantially in unison therewith but against rotation when the inner sleeve is stationary, said cams being shaped to jam against and make a driving engagement with the outer sleeve and to drive the basket shaft when the inner sleeve revolves faster than the said outer sleeve, and said low speed driving shaft and speed reduction gearing cooperating with the clutch to hold the inner sleeve and cams against rotative movement when the outer sleeve is driven by the main driving motor and thereby operating to reduce wear at the inner engaging surface of the clutch.

4. The combination with a centrifugal separator including a basket, of a main electric motor directly connected with the basket shaft to revolve the basket at normal speeds, a clutch mounted on said shaft and comprising inner and outer sleeves concentric with each other and with said shaft, a series of elongated cams parallel with said shaft and interposed between said sleeves, means securing said outer sleeve to said shaft for rotation therewith, a normally idle supplemental motor of smaller horse power than said main motor, a worm gear mounted on said shaft to rotate around it, a worm driven by said supplemental motor and meshing with said worm gear to drive it in the normal direction of rotation of said shaft, means connecting said inner clutch sleeve with said worm gear to cause it to revolve in unison with said gear, means supporting said cams on said inner sleeve for rotation therewith but against rotation relatively thereto when the inner sleeve is stationary, said cams being shaped to jam against the inner surface of the outer sleeve and to make driving engagement therewith when the inner sleeve revolves faster than the outer sleeve and to free the outer sleeve automatically when the latter revolves faster than the inner sleeve, whereby said inner sleeve and said cams remain substantially stationary when said shaft is driven through said outer sleeve by said main motor, including a casing in which said clutch and said worm and worm gear are enclosed, together with a p0r- 'tion of said shaft, an oil well in said casing, a

pump connected with said oil well to draw oil therefrom, means revolving with said outer clutch sleeve for driving said pump, oil distributing means located in the upper part of said casing, connections from the discharge side of said pump for conducting oil therefrom to said distributing means, said oil distributing means including parts for delivering oil to the various friction surfaces of said clutch and said worm and worm gear.

5. The combination with a centrifugal separator including a basket, of a main electric motor directly connected with the basket shaft to revolve the basket at normal speeds, a clutch mounted on said shaft and comprising inner and outer sleeves concentric with each other and with said shaft, a series of elongated cams parallel with said shaft and interposed between said sleeves, means securing said outer sleeve to said shaft for rotation therewith, a normally idle supplemental motor of smaller horse power than said main motor, a worm gear mounted on said shaft to rotate around it, a worm driven by said supplemental motor and meshing with said Worm gear to drive it in the normal direction of rotation of said shaft, means connecting said inner clutch sleeve with said worm gear to cause it to revolve in unison with said gear, means supporting said cams on said inner sleeve for rotation therewith but against rotation relatively thereto When the inner sleeve is stationary, said cams bein shaped to jam against the inner surface of the outer sleeve and to make driving engagement therewith when the inner sleeve revolves faster than the outer sleeve and to free the outer sleeve automatically when the latter revolves faster than the inner sleeve, whereby said inner sleeve and said cams remain substantially stationary when said shaft is driven through said outer sleeve by said main motor, including ball bearing located between said clutch sleeves and maintaining them in fixed spaced relationship to each other, and additional ball bearings supporting said shaft above said clutch, a casing in which said clutch, said worm and said worm gear and a portion of said shaft are enclosed, an oil well in said casing, a pump connected with said oil well to draw oil therefrom, an eccentric revolving with said outer sleeve for driving said pump, an oil receptacle in said casing above said worm and said ball bearings, and means for conducting oil from said receptacle by gravity to said worm, said ball bearings and the friction urfaces of said clutch.

JOHN E. THOLL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,235,633 Anderson et a1 Aug. 7, 1917 1,545,065 Randolph et a1 Jul 7, 1925' 1,952,461 Roos Mar. 27, 1934 2,112,430 Tholl Mar. 29, 1938

Images