US3518798A - Polishing machine - Google Patents

Description

July 7, 1970 Filed Aug. l0, 1967 S. A. BOETTCHER 3,518,798 POLISQHNQMACHINE 2 Sheets-Sheet l J/ZQ gl f2@ /22 @E o@ J 1g) U f /i Y1! i Z026 25 2516 62 5g 62 D 60 l @e 6@ 5432 3. v v 10g@ gg .92 @9 16? wmf JE il 73 @-4 W7 m ya@ @a Al 56 @e 56 52 }l1\ I \m C9@ 45 \347 Inz/enm-f Silvfzz/@eE/ J1115"'7, 1970 s. A. BoET-rcl-IER 3,518,798 i Pop'lrun MACHINE Filed Aug. 10. 1967 2 Sheets-Sheet f United States Patent O M' 3,518,798 POLISHING MACHINE Stephen A. Boettcher, Riverwoods, Deerfield, Ill., as-

signor to Speedfam Corporation, Skokie, Ill., a corporation of Illinois Filed Aug. 10, 1967, Ser. No. 659,780 Int. Cl. B24b 5/00 U.S. Cl. 51-131 10 Claims ABSTRACT OF THE DISCLOSURE A verticaly movable pressure disc having means at the lower surface thereof engageable with means at the upper surface of a load plate to which work pieces are affixed for engagement With a polishing wheel assembly. Surrounding the polishing wheel assembly is an annular shroud which is supported in either one of two vertical positions.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates generally to a polishing machine comprised of a rotatable polishing wheel assembly, and means for urging work pieces to be polished into engagement with the upper surface of the polishing wheel assembly.

Description of the prior art One general class of polishing machine comprises a horizontal rotatable backing wheel, a polishing cloth extending across the upper surface of the backing wheel, and a load plate adapted to have work pieces affixed to the lower surface thereof and to be positioned over the backing wheel with the work pieces engaging the polishing cloth. For effective polishing, it is desirable that pressure be applied through the load plate to the work pieces while the later are being polished.

Heretofore, pressure has been applied either at thc Center of the load plate, or at the outer periphery of the load plate, or across the entire surface of the load plate, which plate must be relatively thin to dissipate heat. Each of these techniques has disadvantages. In the rst case, the outer periphery of the load plate tends to deect upwardly; and, in the second case, the center of the load plate tends to deflect upwardly. In the third case, if the pressure applying member directly engages the load plate, distortion results due to the lack of flatness of the engaged surfaces of the two members, while, if a spongy material is interposed between the pressure applying member and the load plate to accommodate lack of atness, diculty is experienced in separating the load plate from the pressure member during unloading of the machine, as they become wet with polishing mixture during operation.

Also, prior art polishing machines have not been satisfactorily arranged either to prevent spray from the machine of polishing mixture discharged radially from the polishing cloth or to prevent a load plate accidentally released from the pressure applying member from being thrust radially outwardly of the machine.

SUMMARY OF THE INVENTION In accordance with the present invention, a generally horizontal pressure disc having engagement means at the lower surface thereof is connected to the lower end of a vertically movable vertical spindle mounted on the framework of the machine, and the load plate is provided with engagement means at the upper surface thereof located radially intermediate of the center and outer periphery thereof. The pressure disc is vertically 3,518,798 Patented July 7, 1970 lCC movable with the spindle whereby the engagement means of the pressure disc may be selectively engaged with the engagement means of the load plate. By locating the engagement means radially intermediate of the center and outer periphery of the load plate, objectionable deection of the load plate is minimized, without interfering with separation of the load plate from the pressure disc during unloading of the machine. In addition, a universal connection is provided between the pressure disc and the spindle to accommodate floating of the load plate as the work pieces are being polished.

Still further, an annular thin-walled shroud is disposed about the backing wheel, and means are provided for supporting the shroud with the top thereof in either one of two vertical positions. In one position, the top of the shroud lies slightly below the level of the polishing cloth to accommodate movement of the load plate and work pieces onto and off of the polishing cloth. In the second position, the top of the shroud is positioned above the level of the polishing cloth to receive and deflect downwardly polishing mixture discharged radially from the polishing cloth and to serve as a barrier to prevent a load plate accidentally released from its associated pressure disc from being thrust radially outwardly of the machine. Thus, the shroud confines polishing mixture and loose load plates within the machine for cleanliness and safety, without interfering with loading and unloading of the machine. Additionally, the support means for the shroud is arranged to permit adjustment of the plane of the top of the shroud.

With the polishing machine of the present invention, the -known requirements of pressure, speed, ease of parts handling, cleanliness and cooling have been satisfied in one unit for the rst time.

DESCRIPTION OF THE DRAWINGS FIG. l is an elevational view, with portions being broken away and shown in section, of a polishing machine incorporating the principles of the present invention;

FIG. 2 is a horizontal view on an enlarged scale, taken substantially along the line 2-2 in FIG. 1, looking in the direction indicated by the arrows;

FIG. 3 is a sectional view, taken substantially along the line 3-3 in FIG. 2, looking in the direction indicated by the arrows;

FIG. 4 is a sectional view on a further enlarged scale, taken substantially along the line 4-4 in FIG. 2, looking in the direction indicated by the arrows; and

FIG. 5 is a developed planar view on an enlarged scale, taken substantially along the line 5-5 in FIG. 3, looking in the direction indicated by the arrows; and illustrates a portion of the shroud and the support means therefor of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. l, there is indicated generally by the reference numeral 10 a polishing machine incorporating the principles of the present invention. The polishing machine 10 comprises framework including a substantially cylindrical housing 12 supported by a base ring 14. Suitably secured to the opposite sides of the housing 12 are the lower ends of vertical columns 16. Extending between the upper ends of the columns 16 is a horizontal bridge member 18 provided with opposed pairs of lateral arms 20. Mounted at the outer end of each of the arms 20 is a vertical pneumatic piston and cylinder assembly 22 which includes a cylinder 24, a stabilizer sleeve 25 and piston rod 26.

A cylindrical collar 28 is mounted at the upper end of the housing 12 by means of an annular inclined wall 30. Also mounted in the housing 12 is a main drive motor 32 operatively connected to a conventional speed reducer unit 34 supported in the collar 28. Secured to the output shaft 36 of the speed reducer unit 34, as shown in FIG. 3, is a hub member 38 to which is secured, as by bolts 40, a base plate 42.

The base plate 42 serves to support, and to effect rotation of, a polishing wheel assembly 44 comprised of an annular backing wheel 46 and a polishing cloth 48 extending across the upper face thereof. The backing wheel 46, which is preferably formed of a metal, such as brass, having a high heat conductivity, is secured to the base plate 42 by bolts 50. The polishing cloth 48, whlch may for example be either sail cloth or a synthetic non-woven cloth, is retained in position by means of a ring or hoop member 52 suitably clamped about the outer periphery of the backing wheel 46. In place of cloth, a felt material may be either clamped to the backing wheel 46 or glued thereon.

A freely flowing polishing mixture is adapted to be fed to the polishing wheel assembly 44 by a tube or spout 54 extending downwardly from the bridge member 18 as shown in FIG. l. The mixture is delivered to the spout 54 through tubing 56 connected to a sump pump unit 58 located in the lower portion of the housing 12. The polishing mixture flowing from the polishing wheel assembly 44 is collected by the inclined wall 30, which serves as a drip pan, and is directed to a drain. The polishing mixture may, by way of example, comprise a polishing compoundsuch as one having an abrasive base of iron oxide, ceri-um oxide or zirconium oxide-suspended or mixed in water.

Secured in the lower end of each of the piston rods 26 is a vertical spindle 60 having a collar 62 adjacent the upper end thereof. Connected to the lower end of each of the spindles 60, as shown in FIG. 4, is a generally horizontal circular pressure disc 64 having engagement means in the form of an annular ridge 66 at the lower surface thereof. Provided between the spindle 60 and the pressure disc 64 is universal connecting means comprising a ball bearing assembly 68 having an inner race 70 secured to the spindle 60 and an outer race 72 with a convex spherical outer periphery. A bushing ring 74 is secured in a central recess in the pressure disc 64 and has a concave spherical inner periphery that mates with the spherical periphery of the outer race 72. The bushing ring 74 is maintained in position by a retaining plate 76 secured to the pressure disc 64 by screws 78. Secured to the spindle 60 immediately above the retaining plate 76 is a colla1 80 which serves to shield the bearing assembly 68 from polishing mixture and other foreign material.

Associated with each pressure disc 64 is a generally horizontal circular load plate 82 which is adapted to have work pieces 84 affixed to the lower surface thereof and which has engagement means in the form of an annular recess 86 at the upper surface thereof. The recess 86, which is adapted to receive the annular ridge 66 of the pressure disc 64 is located radially intermediate of the center and outer periphery of the load plate 82; and the radii of curvatures of the annular ridge 66 and the annular recess 86 are approximately one-half the radius of curvature of the outer periphery of the load plate `82. With this arrangement, deflection of the load plate 82 is minimized when presure is applied by the press-ure disc 64 through the plate 82 to the work pieces 84 while the latter are being polished on the polishing wheel assembly 44.

Surrounding the polishing wheel assembly 44 is an annular thin-walled shroud 88 having an upper inwardly curved wall portion 90. Support means for the shroud 88 comprises a plurality of circumferentially spaced post means 92, preferably numbering three, mounted horizontally in the housing 12, and a plurality of cut-outs 94 provided in the shroud 88 at locations corresponding to the post means 92. As shown in FIGS. 3 and 5, each post means 94 includes a threaded stud member 96 on which is threaded a sleeve member 98 having an outer peripheral portion eccentric to the axis of the stud member 96. Each cut-out 94 presents a pair of circumferentially spaced upper and lower horizontal ats 100 and 102, a shoulder 104 at the lower at 102, and an inclined cam surface 106 extending between the flats 100 and 102. The post means 92 are selectively engageable either by the upper ats 100 or the lower flats 102 upon limited rotation of the shroud 88 to support the latter in either one of two vertical positions. The cam surfaces 106 are adapted to ride over the post means 92 as the shroud 88 is rotated to facilitate movement of either the upper flats 100 or the lower flats 102 into engagement with the post means 92. Secured to the shroud 88 are hand knobs 108 which may be gripped by an operator for convenience in rotating the shroud 88.

In preparation for polishing, the pneumatic assemblies 22 are suitably actuated to retract the piston rods 26 and the spindles 60 upwardly to a position where the collars 62 engage the stabilizer sleeves 25. The shroud 88 is rotated to engage the upper flats 100 with the post means 92 as shown in solid lines in FIG. 5, and the top of the upper wall portion is thereby positioned slightly below the upper surface of the polishing wheel assembly 44 as shown in solid lines in FIG. 3. Typically, the top of the upper wall portion 90 is positioned .005 to .020 of an inch below the upper surface of the polishing cloth 48. In this position of the shroud 88 the work pieces 84 are permitted to clear the shroud 88 without contact as the load plates 82 and work pieces 84 are slid horizontally onto and off of the polishing cloth 48.

At a location remote from the machine 10, work pieces 84 to be polished are axed, for example by paraffin, in a known manner to the lower surfaces of the load plates 82. The load plates 82 and Work pieces 84 aixed thereto are then moved onto the polishing wheel assembly 44 and positioned beneath the respective pressure discs 64. The pneumatic assemblies 22 are actuated to distend the piston rods 26 and the spindles 60 downwardly until the ridges 66 of the pressure discs 64 are engaged under the desired pressure in the recesses 86 of the load plates 82. Also, the shroud 88 is rotated to engage the lower flats 102 with the post means 92 as shown in dotted lines in FIG. 5, and the top of the upper wall portion 90 is thereby positioned above the upper surface of the polishing wheel assembly 44 as shown in dotted lines in FIG. 3. The shroud 88 is releasably maintained in elevated position by the shoulders 104.

Next, the polishing wheel assembly 44 is rotated and polishing material is delivered from the spout 54 to the surface thereof. When the shroud 88 is in the elevated position, it serves to receive polishing mixture discharged radially from the polishing wheel assembly 44 and to deflect the same downwardly toward the drip pan 30. Also, the shroud 88 serves as a safety barrier to prevent a load plate accidentally released from its associated pressure disc from being thrust radially outwardly of the machine. The spindles 60` and pressure discs 64 serve to center the load plates 82, and the universal connections between the spindles 60 and pressure discs 64 accommodate floating of the load plates 82, as work pieces are being polished. The diameter of each load plate 82 may be substantially the same as, less than, or greater than, the radial width of the annular surface of the backing wheel 46.

Upon completion of the polishing operation, drive of the polishing wheel assembly 44, and delivery of polishing material thereto, are interrupted; the spindles 60 are retracted and the pressure discs 64 withdrawn from engagement with the load plates 82; the shroud 88 is moved to its lowered position; and the load plates 82 and work pieces affixed thereto are slid off of the polishing wheel assembly 44. When necessary, the sleeve members 98 of the post means 92 may be individually rotatably adjusted on the stud members 96 to effect adjustment of the plane of the top of the shroud 88 relative to the upper surface of the polishing wheel assembly 44 when the upper ats 100 are engaged with the sleeve members 98.

While there has been shown and described a preferred embodiment of the present invention, it will be understood by those skilled in the art that various rearrangements and modifications may be made therein without departing from the spirit and scope of the invention. Also, it will be appreciated that in the drawings certain elements of the machine -for example, the cloth 48- have been exaggerated from the true scale for the sake of clarity of illustration.

I claim:

1. In a polishing machine having framework, a polishing wheel assembly mounted on the framework on a vertical axis, means for rotating the polishing wheel assembly, and at least one vertically movable vertical spindle supported from the framework above the polishing wheel assembly, the improvement which comprises a generally horizontal pressure disc having engagement means at the lower surface thereof, means connecting the pressure disc to the lower end of the spindle, a generally horizontal circular load plate having engagement means at the upper surface thereof shaped to coact with said disc engagement means and located exclusively radially intermediate of the center and outer periphery thereof, said load plate being adapted to have work pieces aiiixed to the lower surface thereof and being positionable beneath said pressure disc with the work pieces aflxed thereto engaging the polishing wheel assembly, and said pressure disc being vertically movable with the spindle independently of said load plate whereby said engagement means of said pressure disc may be selectively engaged with and disengaged from said engagement means of said load plate.

2. The improvement of claim 1 wherein said engagement means of said pressure disc comprises an annular ridge, said engagement means of said load plate comprises an annular recess, and said annular ridge is selectively engageable in said annular recess.

3. The improvement of claim 2 wherein the radii of curvatures of said annular ridge and said annular recess are approximately one-half the radius of curvature of the outer periphery of said load plate.

4. The improvement of claim 1 wherein said connecting means comprises a universal connection.

5. The improvement of claim 3 wherein said connecting means comprises a bearing assembly with an inner race secured to the spindle and an outer race having a convex spherical outer periphery, and a bushing ring secured in said pressure disc and having a concave spherical inner periphery mating with said spherical periphery of said outer race.

6. The improvement of claim 1 including an annular shroud surrounding the polishing wheel assembly and having an upper wall portion, and means supporting said shroud with the top of said upper wall portion positioned either slightly below the upper surface of the polishing wheel assembly to accommodate movement of said load plate and work pieces onto and oit of the polishing wheel assembly or above the upper surface of the polishing wheel assembly to receive polishing mixture discharged radially from the polishing wheel assembly and to serve as a safety barrier to prevent said load plate if accidentally released from said pressure disc from being thrust radially outwardly of the machine.

7. In a polishing machine having a framework, a polishing wheel assembly mounted on the framework on a vertical axis, means for rotating the polishing wheel assembly, at least one generally horizontal load plate adapted to have work pieces aflixed to the lower surface thereof and being positionable over the polishing wheel assembly with the work pieces aixed thereto engaging the latter, and means for selectively engaging and centering the load plate, the improvement which comprises an annular shroud surrounding the polishing wheel assembly and having an upper inwardly curved wall portion, and means between the framework and said shroud supporting the latter with the top of said upper wall portion positioned either slightly below the upper surface of the polishing Wheel assembly to accommodate movement of the load plate and work pieces onto and off of the polishing wheel assembly or above the upper surface of the polishing wheel assembly to receive polishing mixture discharged radially from the polishing wheel assembly and to serve as a safety barrier to prevent the load plate if accidentally released from the engaging and centering means from being thrust radially outwardly of the machine.

8. The improvement of claim 7 wherein said supporting means comprises a plurality of circumferentially spaced post means mounted horizontally in the framework, and a plurality of cut-outs provided in said shroud at locations corresponding to said post means and each presenting a pair of circumferentially spaced upper and lower horizontal flats, and said post means being selectively engageable either by said upper ats or said lower ats upon limited rotation of said shroud to support the latter with the top of said upper wall portion in either of said two positions.

9. The improvement of claim 8 wherein each of said cut-outs presents an inclined cam surface extending between said upper and lower ilats, and said cam surfaces are adapted to ride over said post means as said shroud is rotated to facilitate movement of either said upper flats or said lower tlats into engagement with said post means.

10. The improvement of claim 8 wherein each of said post means comprises a horizontal threaded stud member, a sleeve member threaded on said stud member and having an outer peripheral portion eccentric to the axis of the stud member, and said sleeve members are individually rotatably adjustable on said stud members whereby to permit adjustment of the plane of said top of said upper wall portion of said shroud.

References Cited UNITED STATES PATENTS 1,100,845 6/1914 Richter. 2,968,135 1/1961 Boettcher 51-129 3,090,169 5/1963 Boettcher 51-131 3,377,750 4/1968 Day 51-131 FOREIGN PATENTS 863,711 4/1941 France.

HAROLD D. WHITEHEAD, Primary Examiner U.S. Cl. X.R. 51-268

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