US2897633A

US2897633A - Polishing apparatus

Info

Publication number: US2897633A
Application number: US637202A
Authority: US
Inventors: Buhr Erich; Wellner Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-02-11
Filing date: 1957-01-30
Publication date: 1959-08-04
Anticipated expiration: 1976-08-04
Also published as: FR1166221A

Description

Aug. 4, 1959 v E. BUHR L 2,897,633

POLISHING APPARATUS Filed Jan. 30, 1957 IN VEN TORS agT.

ignited S ate Pat 2,897,633 POLISHING APPARATUS Erich Biihr, Stuttgart-Feuerbach, and Paul Wellner, Geislingen (Steige), Germany Application January '30, 1957, Serial No. 637,202

Claims priority, application Germany February '11, 1956 11 Claims. c1. 51-7 The present invention relates to a polishing apparatus.

pressed against the inner surface of the rotating polishing mass.

In apparatuses of this type the drum is normally open "at the top, and a suitable stationary cover is provided for covering the same, such cover being formed with one or more openings therethrough through which the work pieces may be dipped into the interior of the drum. Usually, the upstanding side wall of the drum is formed with an inwardly extending flange, and the cover has an outer rim which is but slightly smaller in diameter than the outer rim of the flange so that a relatively narrow gap is formed between the rotating flange and the stationary cover. Inasmuch as contact between the work pieces and the rotating polishing mass will inevitably force a number of individual granular particles out of the polishing mass, some of these particles will tend to escape from the interior of the drum by way of this gap. It has therefore been found necessary in some way to prevent the egress "of granular material.

It has been sought to accomplish this result by maintaining the gap extremely small. However, this solution has not proved satisfactory inasmuch as in order to maintainthe gap very small while at the same time affording suflicient clearance between the inner rim of the flange and the stationary cover to permit free rotation of the drum, the latter must be mounted in such a manner as to be capable of rotating without undergoing any perceptible wobbling. Such mounting arrangements are rather expensive and complicated, particularly when a drum is involved the diameter of which is of the order of 3 meters.

Alternatively, it has been suggested to provide sealing means, such as a labyrinth seal, for preventing the loss of granular particles. However, such seals have not been 'found to be particularly effective, especially since even with such seals the mounting of the drum must be such as to'permit substantially wobble-free rotation.

. It is therefore an object of the present invention to proportion.

a rotatable substantially cup-shaped drum having a bottom portion and. an annular upstanding wall-portion, covering means arranged near the upper rim of the wall portion but spaced therefrom so that an annular gap'is formed between the rim and the covering means, and means for moving air through the gap from the exterior of the drum to the interior thereof during rotation of the drum. As a result, a mass of granular material in the drum will, during rotation thereof, be centrifuged against the upstanding wall while individual granular particles will be prevented [from leaving the interior of the drum through the gap by the air moving therethroug'h in the opposite direction.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which: I

Fig. 1 is an elevational view, partly in section, of one embodiment of the present invention;

Fig. 2 is a sectional view on a larger scale of a detail of the present invention;

Fig. 3 is a fragmentary sectional view taken substantially along line 3-3 of Fig. 2; and

Fig. 4 is a sectional view on an enlarged scale of a different embodiment of the detail illustrated in Fig. 2. Referring now to'the drawing, and to Figs. 1-3 thereof in particular, there is shown a housing or support '1 in which a substantially cup-shaped drum 3 is arranged. The drum 3 has a bottom portion 4 carrying a stud 5 which is rotatably received by a bearing 6 so that the drum is rotatably mounted onthe support 1. The drum also has an upstanding annular wall portion 7 the height of which is relatively small in comparison to diameter of the drum. The wall portion 7 is formed with an inwardly extending annular flange portion 8 which carries an annular element 9 constituting the inner rim of the flange The drum 3 carries a friction ring 10 which is mounted on the outer surface of the wall portion 7 so that the drum may be. rotated by a rotatably mountedfriction roller 11, the latter being driven in any suitable manner (not shown).

The support 1 also carries a stationary cover 2 which is formed with a downwardly depending annularwall portion 2a which carries another annular element 13. The arrangement and construction of the parts is such that elements 9 and 13 are substantially concentric and form between themselves a relatively large and preferably downwardly tapering gap 14.

The drum contains a mass of granular material the quantity being so selected that when the drum is rotated, substantially all of the granular particles are centrifuged against the upstanding wall portion 7 and into the space beneath the flange portion 8 so as to form an annular polishing mass 12.

The support 1 also supports one or more work piece carriers 15 which are preferably displacedequal angular distances from each other. Each carrier 15 extends over the cover 2 and includes a swingably mounted arm 15 to the free end of which one or more chucks 17 are atthe provision of a polishing apparatus of the above type in mainly resides in a polishing apparatus which includes.

tached, the chucks extending in a direction transverse to the arm 16. Each chuck, only oneof which is shown in Fig. 1, is adapted to grasp a work piece 18, the construction of the chuck preferably being such as to permit rotation or oscillation of each work piece about its own axis so that the'entire surface of the work piece which is'to be polished may be exposed to the action of the polishing mass 12. As may readily be seen from the drawingeach arm is swingable to and from an operative position wherein the work piece 18 is engaged by the polishing mass 12 constituted by the centrifuged particles of the granular material. Theposition of the arm 16 in which the workpiece out of the drum is shown in dotted lines. -'In order to permit the arms 16 to be moved into and, out of the drum, the cover 2 is formed with one or more openings 19, depending upon the number of work piece carriers 15, each opening being in angular registration with its respective carrier so that the correspond ing area 16 may pass through the opening.

As the polishing operation proceeds, individual granular particles will be deflected from their normally circular paths. Most of these particles will fall to the bottom of the drum, where they will again be subjected to the rotation of the drum and be centrifuged back into the annular polishing mass 12. This eflect may be enhanced by providing a dome-shaped insert 20, or by imparting suchv a shape to the bottom portion 4 itself. However, a considerable number of particles will tend to move upwardly and tend to escape from the interior of the drum 3' by way of the gap 14. According to the present invention this is prevented by providing means for moving air through the gap from the exterior of the drum to the interior thereof during rotation of the drum. In this way, the egress of individual granular particles through the gap 14 will be prevented by air flowing therethrough in the opposite direction. Also, the air thus blown into the drum serves to cool the polishing mass 12.

' The means for moving air through the gap 14 may be in the form of a blower arrangement which incorporates an annular nozzle 21 which is arranged below that portion of the cover 2 which is exterior of the depending clockwise rotation of the drum 3 as seen from above in Fig. 1, cause air to flow downwardly through the gap 14.

While the arrangement shown in Fig. 4 may be used in conjunction with the above-described blower means, it has been found that if the drum is rotated sufiiciently rapidly, the blades 30a alone can be relied upon to act as the means for moving air through the gap 14. Consequently, a polishing apparatus incorporating the structure shown in Fig. 4 may be constructed without the above-described blower means.

A rake 32 having prongs 33 may be mounted on the cover 2 in such a manner that the prongs extends-into the granular material forming the annular polishing mass 12, thereby continuously raking the latter during rotation of the drum. While this has the desirable result of continuously bringing fresh particles into contact with the work pieces being polished, the turbulence of the air in the drum isincreased, thereby causing a larger number of granular. particles to seek egress'through the gap 14.

This, in turn, increases the need for efliciently preventing the flow of particles through the gap, and this is accomplished by the present invention.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of polishing apparatuses diifering from the types described above. 7

While the invention has been illustrated and described embodied a polishing apparatus in which the drum is formed with an upper inwardly extending flange, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

duit 25 by means of one or more radial conduits 24 ing 19 formed in the cover 2. The hoods are placed in communication with a central conduit 28, which prefer ably encompasses and is concentric with the central conduit. 25, by means of branch conduits 29. The conduit 28 isconnected to a suction device (not shown) by means of another conduit 27 so that any particles seeking to leave the interior of the drum '3 by way of the openings 19 will be sucked in and may in this way be salvaged. In order to accomplish this, the suction device is so adjusted that'it will suck in slightly more air than is blown into the drum 3 through the gap 14 so as to prevent air and consequently granular particles from flowing out of the hoods into the surrounding atmosphere.

It has been found expedient to place a cyclone separator orthe like in communication with the suction means for extracting therefrom granular particles of at least apredetermined mass, so that relatively large particles may be separated from the air suckedin by the sucking deviceand later be returned to the drum.

If desired, baflle means may be arranged in the gap for additionally impeding the egress of granular particles overlap each at least one next adjacent bafile'element, as may be seen in Fig. 3. Theembodiment shownin Fig. 4 diifers from the above- ;described one in that baflle elements 30a are carried by thelrotating annular element 9.rather than the stationary element 13.. .The bathe elements act therefore not "iOIfiYQS 'deflECtOIS; but also as fan blades which, during Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims. I

What is claimed as new and desired to be secured by Letters Patent is: v

1. In a polishing apparatus, in combination, support means; a substantially cup-shaped drum mounted on said support means for rotation relative thereto, said drum having a bottom portioman upstanding annular wall portion, and an inwardly directed annular flange portion; stationary covering means on said support means and arranged near the inner rim of said flange portion-but spaced therefrom so that said drum may rotate freely relative to said covering means and so that an annular gap is formed between said flange portion and said covering means; and blower means including nozzle means arranged above said gap for moving air through said gap from the exterior of said drum to the interior thereof during rotation of said drum, whereby a mass of granular material in said drum will during rotation thereof be centrifuged against said upstanding wall portion thereof into the space beneath said flange portion while individual granular particles will be prevented from leaving said space through said gap by the air moving therethrough in the opposite direction.

2. In a polishing apparatus, in combination, support means; a substantially cup-shaped drum mounted on said support means for rotation relative thereto, said drum having a bottom portion, an upstanding annular wall portion, and an inwardly directed annular flange portion; stationary covering means on said support means and arranged near the inner rim of said flange portion but 'spaced therefrom so that said drum may rotate freely arranged above said gap and being in registration therewith for moving air through said gap from the exterior of said drum to the interior thereof during rotation of said drum, whereby a mass of granular material in said drum will during rotation thereof be centrifuged against said upstanding wall portion thereof into the space beneath said flange portion while individual granular particles will be prevented from leaving said space through said gap by the air moving therethrough in the opposite direction.

3. The combination defined in claim 2, and deflector means arranged in said gap for additionally impeding the egress of granular particles through said gap.

4. The combination defined in claim 3 wherein said deflector means include a plurality of bafiie elements on said covering means and extending across said gap, said baflle elements being inclined to a plane normal to the axis of said drum, each bafile element being so arranged as to overlap at least one of its next adjacent bafiie elements.

5. In a polishing apparatus, in combination, support means; a substantially cup-shaped drum mounted on said support means for rotation relative thereto, said drum having a bottom portion, an upstanding annular wall portion, and an inwardly directed annular flange portion; stationary covering means on said support means and arranged near the inner rim of said flange portion but spaced therefrom so that said drum may rotate freely relative to said covering means and so that an annular gap is formed between said flange portion and said covering means; and means for moving air through said gap from the exterior of said drum to the interior thereof during rotation of said drum, said moving means including nozzle means arranged above said gap and blower means for blowing air therethrough, said moving means further including a plurality of blades in said gap and connected to said drum for rotation therewith, said blades being so constructed and arranged as to cause the flow of air into said drum through said gap during rotation of said drum, whereby a mass of granular material in said drum will during rotation thereof be centrifuged against said upstanding wall portion thereof into the space beneath said flange portion while individual granular particles will be prevented from leaving said space through said gap by the air moving therethrough in the opposite direction.

6. In a polishing apparatus, in combination, support means; a substantially cup-shaped drum mounted on said support means for rotation relative thereto, said drum having a bottom portion, an upstanding annular wall portion, and an inwardly directed annular flange portion; stationary covering means on said support means and arranged near the inner rim of said flange portion but spaced therefrom so that said drum may rotate freely relative to said 'overing means and so that an annular gap is formed between said flange portion and said covering means; and means for moving air through said gap from the exterior of said drum to the interior thereof during rotation of said drum, said moving means comprising a plurality of blades in said gap and connected to said drum for rotation therewith, said blades being so constructed and arranged as to cause the flow of air into said drum through said gap during rotation of said drum, whereby a mass of granular material in said drum will during rotation thereof be centrifuged against said upstanding wall portion thereof into the space beneath said flange portion while individual granular particles will be prevented from leaving said space through said gap by the air moving therethrough in the opposite direction.

7. In a polishing apparatus, in combination, supportmeans; a substantially cup-shaped drum mounted on said support means for rotation relative thereto, said drum having a bottom portion, an upstanding annulan wall portion, and an inwardly directed annular flange portion; stationary covering means on said support means and arranged near the inner rim of said flange portion but spaced therefrom so that said drum may rotate freely relative to said covering means and so that an annular gap is formed between said flange portion and said covering means; means for moving air through said gap from the exterior of said drum to the interior thereof during rotation of said drum, whereby a mass of granular material in said drum will during rotation thereof be centrifuged against said upstanding wall portion thereof into the space beneath said flange portion while individual granular particles will be prevented from leaving said space through said gap by the air moving therethrough in the opposite direction; and at least one work piece carrier capable of carrying a work piece to be polished, said carrier being mounted on said support for swinging movement relative thereto into and out of an operative position wherein a work piece carried by said carrier is located in said space so as to be contacted and polished by a mass of gnanular material centrifuged against said upstanding wall portion of said drum during rotation thereof.

8. The combination defined in claim 7 wherein said covering means is formed with :at least one opening therethrough through which said carrier extends when the same is in its operative position.

9. The combination defined in claim 8 wherein said carrier is so arranged that when it occupies its operative position, it extends over said annular gap.

10. The combination defined in claim 8, and suction means arranged exteriorly of said drum and being in communication with said opening through said covering means, whereby granular particles escaping from said drum through said opening may be collected and salvaged.

11. The combination defined in claim 10, wherein said moving means include a nozzle arranged [above said gap and blower means for blowing air therethrough, and wherein said blower means and said suction means each include a conduit, said conduits being arranged coaxially with each other throughout at least a portion of their lengths.

References Cited in the file of this patent UNITED STATES PATENTS 2,238,743 Lykken Apr. 15, 1941 2,664,676 Cuppers Jan. 5, 1954 2,699,293 Svendsen Jan. 11, 1955 2,734,317 Bond Feb. 14, 1956