US2891357A - Apparatus for polishing work pieces - Google Patents

Description

June 23, 1959 L. R. DAVIDSON APPARATUS FOR POLISHING WORK PIECES 4 Sheets'-Sheet 2 Filed Feb. 8. 1956 4 INVENTOR. 1:0 Ava/Ana om /aso/v ATTOAIVA'YJ June 23, 1959 R. DAVIDSON 2, 7

APPARATUS FOR POLISHING WORK PIECES Filed Feb. 8. 1956 4 Sheets-Sheet 3 BY W MM June 23, 1959 L. R. DAVID'SON 2,891,351

APPARATUS FOR POLISHING WORK PIECES APPARATUS FOR POLISHING WORK PIECES Leo Richard Davidson, Sturgis, Mich.

Application February 8, 1956, Serial No. 564,245

' 18 Claims. (c1. 51-7 This invention relates to an apparatus for imparting desired finishes to Work pieces such as, for example, might be required prior to plating a work piece.

It is an object of this invention to provide a machine of the-class described which is very efficient in its operation, that is, it produces a faster cut and a finer finish than can be produced with other machines for performing the same type of work such as tumbling machines.

A further object of the invention is to provide a machine of the class described which is designed such that it can be operated, loaded and unloaded in a very easy manner.

More particularly, the invention has to do with a machine for finishing work pieces such as by deburring, polishing, etc. The machine includes a horizontally disposed reel journalled for rotation on fixed supports and a drum containing the polishing media and compound and in which the reel rotates. The reel is arranged to have work pieces mounted thereon in the desired position and the drum is mounted on jacks so that it can be raised and lowered so as to bring the reel into and out of the media in the drum. Other novel features and advantages of the machine of this invention are disclosed in the following drawings in which: a

Fig. l is an end view of the machine partly in section showing the drum in fully raised and fully lowered positions.

Fig. 2 is a front elevational view of the machine with the drum in the elevated operating position.

Fig. 3 is a sectional view along the lines 3-3 showing the manner in which the reel spindles are connected to the rotating drive mechanism.

Fig. 4 is a side elevational view of the arrangement shown in Fig. 3.

Fig. 5 is a sectional view along the lines 55 in Fig. 2.

Figs. 6 and 7 are fragmentary detail views taken along the lines 66 and 77, respectively, in Fig. 5.

Fig. 8 is a fragmentary sectional view taken generally along the lines 88 in Fig. 2.

Fig. 9 is a fragmentary sectional view taken generally along the lines 99 in Fig. 8.

Fig. 10 is a sectional view taken along the lines 10-40 in Fig. 2.

Referring more particularly to Fig. 1, the machine of the present invention includes a supporting base 10 and side frames 12 on which the various mechanisms are mounted. Base 10 and side frames 12 are formed as welded structural assemblies. On side frames 12, there are mounted four jack screws 14, two at each end of the machine. A suitable drive mechanism 16 connected through a reduction gearing to a motor 18 is arranged to operate screws 14 in unison. At their upper ends, each screw is connected with a pad or bracket 29 mounted on the end walls 22 of the drum 24. Drum 24 is guided for vertical movement by means of an upright guide plate 26 fixedly supported on base 10 and having vertical edges which are engaged by spaced apart ways 28 secured to the end walls 22 of drum 24 as shown in Fig. 1. Each side frame 12 includes a top horizontally extending member 30 on which aligned pillow blocks 32 are mounted, one at each end of the machine. In each of the pillow blocks 32, there is journalled a stub axle 34. The axles 34 extend through nitcd States Patent 0 F radius.

Patented June 23, 1959 a vertically elongated opening 36 in the end walls 22 of drum 24; and at'their inner ends, these stub axles are provided with chucks 38 for receiving the ends of the reel spindle 40.

Chucks 38 are shown in detail in Figs. 3 and 4. Each chuck includes a U-shaped block 42, one welded to the inner end of each stub axle 34. Blocks 42 have a hook portion 44 at the upper end of one of the legs of the U. The other leg of the U has a horizontally elongated opening 46 therein. A latch bar 48 is pivoted in opening 46 by means of a pin 50. At its free end, latch bar 48 is provided with a hook portion 52 which is arranged to interengage with the hook portion 44 of the U-shaped block 42 so as to clamp in the socket 54 formed therebythe square end 56 of the reel spindle 40. In the engaged position of latch bar 48 (Fig. 3), a spring biased detent 58 engages in a socket 60 in block 42 to hold the latch bar in latched position. Detent 58 is formed with a looped handle 62 at the upper end thereof by means of which the detent can be lifted out of engagement with socket 60 so as to permit the latch bar with its pin 50 to be shifted longitudinally in opening 46 and thereby disengage the hook portions 52 and 44 to permit the latch bar to be pivoted upwardly and thus enable removal of the spindle ends 54 from the chucks.

One of the stub axles 34, the one shown at the right of Fig. 2, has alarge sprocket 64 keyed thereto. Sprocket 64 is driven by a chain 66 which wraps around a driving a speed reduction gearing. These individual mechanisms are not illustrated.

Referring more particularly to Fig. 5 now, reel 72 includes a disc 74 at each end thereof which is fixed on spindle 40 and a plurality of longitudinally extending bars 76 are connected at opposite ends as by screws 78 to the discs74. In the arrangement shown, two discs 74 are employed and the bars 76 extend the full length of the reel. number of discs employed in the reel need not be limited to two and that the bars 76 need not extend continuously from one end of the reel to the other. Some of the bars 76 have short bafile plates 86 welded thereto. Bafiies 80 are arranged obliquely to the longitudinal axis of the reel. Others of the bars 76 have mounting fixtures 82 arranged thereon for supporting the work pieces to be finished.

In the drawings, the work pieces are represented as handles 84 and the fixtures 82 are arranged so that the handles 84 are inclined obliquely to the longitudinal axis of the reel as is the case with baffie plates 80 and in addition are inclined at an angle less than to the See Fig. 5.

Drum 24 is fashioned with an axially extending side wall 86 which, for convenience, may be formed as a plurality of angularly related faces. The side wall 86 terminates at its upper edges as inwardly turned flanges 88 and .90 so that the drum 24 is opened at the top. A

cover 92 is arranged to close the open top of drum 24 when in the elevated position. At each end, cover 92 has an arm 94 connected therewith. The free end of each arm 94 is fixed to a shaft 96 which has a sprocket 98 keyed thereto- Sprocket 98 is arranged to be driven in opposite directions by an electric motor 100 through a speed reduction gearing 102 and a chain 104. This arrangement enables the cover 92 to be pivoted upwardly about shaft 96 from the closed position shown in Fig. 1 to the open position wherein the reel 72 is accessible through the open upper end of drum 24.

It will be appreciated, however, that the At the front face of side Wall 86, there is provided a pair of washout openings 106 which are spanned by a screen 108. Each opening is arranged to be closed by a cover 110 which is pivoted on the side wall 86 as at 112. Screws 114, provided with handles 116, are threaded through brackets 118 for securely clamping covers 110 in the closed position over openings 106. At the lower end of the front face of side wall 86, there is provided a pair of discharge openings 120 which are arranged to be closed by doors 122. Doors 122 are provided with rectangular openings 124 therein, and the openings 124 are spanned by metallic screen sections 126 (Fig. 8). The openings 124 are in turn arranged to be closed by auxiliary doors 128. The hinge arrangement for doors 122 and auxiliary doors 128 is shown in Fig. 9 and includes an angle member 130 having end walls 132. Each end wall 132 is hinged as at 134 on a bracket 135 mounted on the side wall 86 of the drum. Doors 122 are also provided with brackets 137 to which end plates 132 are pivoted as at 139. A pair of hinge arms 136 are pivotally supported on door 122 as'at 138 and are pivotally connected with door 128 as at 140. A screw 142 threaded on angle 130 is arranged to engage with a wedge block 144 on hinge arm 136 to clamp door 128 tightly against door 122 over opening 124. Door 122 is in turn actuated by a screw 146 which is threaded in a collar 148 pivoted as at 150 between ears 152 on a bracket 153 anchored to the side wall 86 on the drum. On one end, screw 146 is provided with a hand wheel 154; and at its other end, screw 146 is sleeved for rotation in a bracket 156 which is pivoted between ears 157 on angle 130 as at 158. Adjacent openings 120, baffies 159 and 161 are welded to the inside of drum 24 so as to direct the material in drum 24 through openings 120 when doors 122 are opened.

In operation, reel '72 is removed from within drum 24 and loaded with the work pieces such as shown at 84 that are to be finished. The drum 24 is charged to about the level indicated at 160 in Fig. with the material to be used for finishing the work pieces. The particular material used depends primarily on the operation to be performed. For example, in the case of an operation in the nature of grinding or deburring, the material comprises some sort of a chip media such as aluminum oxide particles, limestone, granite chips, etc. and a finishing compound preferablyof the type that will not coat the abrasive chips. Such a compound may consist of an animal or vegetable fat type soap as a lubricant and preferably containing a wetting agent, sodium metasilicate as a cleanser, a borax and tri sodium phosphate as a water softener, and pumice or other fine abrasive to assist in the coating action. A compound of this type has general application for use with both ferrous and nonferrous metals. The compound may vary widely in composition and the following example is simply a typical formula that may be employed, the proportions being given in parts by weight:

If the operation to be performed is one of preparing the work pieces for plating, that is, an operation that might be comparable to hand bufiing prior to color bufiing, the tank 24 is charged with a different material. In this case, preferably black marble chips ranging in size from to A of an inch are employed as the media. Dolomite limestone chips or other relatively soft chips may also be used, but I have found that best results are obtained with black marble chips. A compound of the type that will coat the media is used with these chips. This coating compound preferably comprises a water softener such as borax and tri sodium phosphate, a cleanser such as sodium metasilicate, a lubricant of animal and/or vegetable soap and a soft clay such as bentonite clay. A brightener such as sodium chromate may also be incorporated. The composition of this compound, as is true of the compound previously described, may vary within relatively wide limits. As an example of a typical composition, the following formula may be used, the proportions being given in percentage by weight:

Percent Borax I 19 Tri sodium phosphate 3 Sodium metasilicate l3 Soap 30 Clay 35 The amount of compound used in relation to the media will vary, of course, with the operation being performed and the speed with which it is desired to perform the operation. For example, in a typical polishing operation, the drum 24 may contain about 3,000 pounds of marble chips; and at the start of the operation, 10 pounds of the above compound may be incorporated. Additions of 2 pounds per hour of the compound may be made in an 8- hour run.

Likewise, the amount of water that is added to the tank will vary in accordance with the work to be performed. The water content may vary in amounts from where the water content is just sutlicient to wet the chips to where the water content rises to a level to completely cover the chips. Generally speaking, the rate of cutting and the smoothness of the finish obtained will vary inversely with the water content, a very fluid mass producing slow cutting and a very fine finish and a rela tively dry mass producing a very fast cut with a less smooth finish.

In finishing work pieces where a coating compound of the type described immediately above is employed, it is necessary to control the pH of the solution quite carefully; and this is particularly true with reference to non-ferrous work pieces. I have found that in the case of non-ferrous Work pieces, the pH of the solution should be within the range of 10 to 15, and preferably between 10.5 and 12.0. I have found that below 10, non-ferrous work pieces are subject to attack or etching, thus leaving a pitted surface; and when the pH of the solution is above 15, black spots appear on the work pieces which are very difficult to remove. In the case of ferrous work pieces, control of the pH is not so critical. However, the most satisfactory results are obtained when the pH of the solution is between 7.0 and 10.5. Below a pH of 7.0, the solution tends to be acidic in nature and pitting may result. The pH of the compound can be controlled by additions of potassium hydroxide.

If the operation to be performed is in the nature of burnishing, then a compound coating of the type described immediately above with reference to preparation of a surface for plating is employed in drum 24; but instead of marble chips, it is preferred to use a softer media such. as crushed clam shells, oyster shells or nut shells. In this type of operation, it is also necessary to control the pH of the solution as described above with reference to non-ferrous and ferrous work pieces.

While use of the above media and compounds is not absolutely required in the machine described herein, numerous tests have shown that best results are obtained when such media and compounds are employed. In general, it might be stated that the range. of media usable in the present machine may vary in hardness from 1.0 to 9.0 on Moes scale. Media ranging from 1.0 to 5.0 which include clam shells, etc., limestone and marble chips are used for obtaining a satisfactory cut primarily onnon-ferrous work pieces. Media that range in hardness from about 5.0 to 9.0 which include granite chips and aluminum .oxide are used primarily on ferrous work 5.. pieces and also for the removal of burrs and parting lines on die castings, for example, where the surface finish is not critical, as in the casewith preparation of parts for plating.

After the drum 24 is charged with the proper media and compound and water, the reel 72, with the work pieces mounted thereon, is lowered into engagement in the chucks 32. At this time, drum 24 is in the lowered position indicated by the broken lines 24a in Fig. 1. The power unit 70 is then energized to start the reel rotating at the desired speed. In most instances, the reel is rotated slowly during the initial stages of the operation to obtain a fast cut down on the surface of the Work piece and the operation is completed at a higher speed to produce a fine finish on the work piece. After the reel 72 is set in operation, the motor 18 is energized to slowly elevate drum 24 to the solid line position shown in Fig. 1. The reel is thus in effect fed gradually into the mass of media while it is rotating; and this, of course, requires considerably less power than would be required to start the reel rotating if the drum 24 were initially positioned in the elevated position shown in Fig. 1 with the lower half of the reel buried in the media. As the reel rotates, the work pieces mounted thereon and the bafiles 80 cause the media to flow upwardly in the direction of rotation and then slide downwardly over the mass so as to produce a continual flow pattern as represented by the arrows 161 in Fig. (assuming clockwise rotation of the reel). It is a smooth continuous flow as distinguished from the flow in a conventional tumbling barrel where the media is lifted by the barrel and then dropped back onto the mass. This type of flow of media that is produced by rotating the reel is very desirable from several standpoints. In the first place, by moving the reel through the mass of media, greater friction between the media and the surfaces of the work piece is obtained and a faster and a smoother cut results. At the same time, since the flow is gradual and continuous as distinguished from the flow of a tumbling barrel where-the media is lifted and then dropped, little impingement occurs and the work pieces are thus not apt to become nicked or dented.

The manner in which the work pieces will be supported on the mounting fixtures 82 will, of course, depend upon the size and shape of the work pieces. The instant machine is designed primarily for finishing relatively large work pieces, that is, work pieces that range in size from about 4 to 5 inches and larger. Work pieces of this size are usually considered too large for tumbling barrels. In order to produce the necessary friction to obtain a fast cut on the surface of the work piece in the case of relatively straight work pieces such as the handles 84 shown in the drawings, it is preferred to mount the work pieces so that they extend in a direction at an angle of about 45 to the axis of the reel and at an angle of about 20 to a tangential line at the location of the mounting fixture. This double inclination of the work piece produces the necessary friction between the leading faces of the work pieces and the finishing media in the drum. However, in the case of a work piece such as the handle shown at 84, rotation of the reel in one direction will finish only one-half ofthe surfaces of the handle so the complete cycle comprises two periods. During one-half of the cycle, the reel is rotated in one direction; and during the remaining half of the cycle, the reel is rotated in the opposite direction, so that all of the surfaces of the work piece are finished to the same extent. After the completion of an operation, the reel may be removed from the drum 24, which operation is facilitated by quick opening chucks 38, and conveyed to a rinsing machine and then to a coating machine for a protective dip, if required. In the meantime, another reel may be loaded into the drum 24.

Between successive loads, it will probably be necessary to change media or at least change the solution. If it is merely desired to change the solution, the washout doors and 123 are opened. Washout doors 110 are opened by simply backing off hand screws 116, and washout doors 128 are opened by backing off screws 142 so as to permit doors 128 to pivot downwardly about the hinges 138. With the Washout doors open, rinse water may be caused to flow through flush pipes 162 and 164. Preferably during rinsing, the reel is rotated to obtain a thorough mixing of the rinse water with the media. Flush pipe 162, it will be observed, is located so as to impart considerable agitation to the media at the bottom of the tank adjacent flush out doors 128. The rinse water is flushed out through openings 106 and 124 while the media is retained within the drum by means of the screens over these openings.

If instead of simply rinsing the media, it is desired to change the media in the drum, then hand wheels 154 are turned to back ofi screws 146 and thus pivot doors 122' about hinges 134 and discharge the contents of the tank into pans (not shown) located below openings 120. Doors 1113, 1'22 and 128 are provided with. seals to provide leakproof closures.

Thus, it will be seen that I have provided a machine for finishing work pieces which is not only convenient to use since it does not require loading of the reel with work pieces while it is disposed in the drum, but also results in a very eflicient cutting action. In addition, the provision of a vertically movable tank in which the reel is housed permits the use of a motor for rotating the reel of less starting torque than would otherwise be required and at the same time facilitates loading and unloading the machine with work pieces and media. It will be appreciated, of course, that the reel 72 may be loaded or unloaded with work pieces without removing it from the machine. This is facilitated by simply lowering the drum 24.

I claim:

1. A machine for polishing work pieces comprising a drum adapted to contain polishing media, a reel in said drum journalled on a fixed horizontal axis for rotation about said horizontal axis, said reel containing a plurality of supports around the periphery adapted for mounting work pieces to be polished on said reel whereby the work pieces are conveyed in a circular path downwardly through polishing media in the drum and then upwardly out of the media when the reel is rotated, means for rotating said reel and means for moving said drum vertically while the reel is rotating about said fixed horizontal axis whereby at least the lower portion of said reel can be progressively submerged in polishing media contained in said drum while the reel is rotating.

2. A machine as called for in claim 1 wherein said last mentioned means comprise mechanism for moving at least the lower portion of said drum vertically towards and away from said reel.

3. A machine for polishing work pieces comprising a generally cylindrical hollow drum having its longitudinal axis extending horizontally, a reel arranged in said drum.

for rotation about a horizontal axis, said reel having a plurality of support bars extending longitudinally thereof and arranged in circumferentially spaced relation around the periphery of the reel, means for rotating said reel about said horizontal axis so that said support bars are successively moved downwardly into the media in the lower portion of the tank and then upwardly out of said media and members mounted on said support bars and extending obliquely thereof for imparting turbulence t said media when the reel is rotated.

4. A machine as called for in claim 3 wherein at least some of said obliquely disposed members on said support bars comprise baffle plates, said bafiie plates being mounted on said support bars such that the planes thereof are inclined axially to the axis of rotation of said reel. 5. A machine as called for in claim 3 wherein at least some of said obliquely disposed members on said support bars comprise work pieces.

6. A machine as called for in claim 3 including means for relatively moving said tank and reel vertically while the reel is rotating.

7. A machine for polishing work pieces comprising a drum adapted to contain polishing media, a reel in said drum journalled for rotation about a horizontal axis, said reel containing a plurality of supports thereon adapted for mounting work pieces to be polished on said reel whereby the Work pieces are conveyed downwardly through polishing media in the drum and then upwardly out of the media when the reel is rotated, means for rotating. said reel and means for relatively moving said reel and drum vertically while the reel is rotating whereby at least the lower portion of said reel can be progressively submerged. in polishing media contained in said drum while the reel is rotating, said reel being jouinalled at each end for rotation on fixed supports and said last mentioned means comprising mechanism for moving at least the lower portion of said drum vertically towards and away from said reel, said reel being provided with an axially projecting spindle at each end thereof by means of which said reel is journalled for rotation, said drum having walls at each end thereof, said walls being provided with openings through which said spindles project, said openings beingvertically elongated and ex tending downwardly from the upper portion of said end walls to approximately the longitudinal axis of said drum.

8. A machine for polishing work pieces comprising a generally cylindrical hollow drum having its longitudinal axis extending horizontally, a reel removably arranged in said drum for rotation about a horizontal axis, said reel having a plurality of work supporting fixtures thereon, means for rotating said reel in opposite directions and at a variable speed, a plurality of jacks for raising and lowering said drum relative to said reel, means for slowly actuating said jacksupwardly and downwardly while said means for rotating said reel are in operation, a supporting structure for said drum and reel, said jacks being connected at one end to said supporting structure and at their opposite end to said drum and cooperating track and guide means on said drum and supporting structure for guidingv the vertical. movement of said drum, said drum. being provided adjacent the lower end thereof with at least one opening for discharging polishing media from the drum, a cover. for closing said opening, said cover having an opening therein, a perforated panel overlying said last mentioned opening for enabling the liquid in said drum. to be discharged while retaining the solid media and a second cover mounted on said first cover for closing said second mentioned opening.

9. A machine as called for in claim 8 wherein said tank is. open at the upper end thereof, said open end being of a size to pass the reel therethrough and including a cover. for closing said open end of the tank.

10. A machine for polishing work pieces comprising a generally cylindrical hollow drum adapted to contain polishing media and having its longitudinal axis extending horizontally, a reel arranged within said drum for rotation about a horizontal axis, said reel having a plurality of work supportingfnxtures thereon, means for rotating said reel, saiddrum being provided adjacent the lower end thereof with at least one opening for discharging po-lishing media from the drum, a cover for closing said opening, said cover having an opening therein, a perforated panel overlying said last mentioned opening for enabling the liquid in said drum to be discharged while retaining the solid media and a second cover mounted on said first cover for closing said second mentioned opening.

11. A machine as called for in claim 10 wherein said reel is removably mounted within said drum.

12. A machine for polishing work pieces comprising a fixed support, a drum adapted to contain polishing media and having its longitudinal axis horizontally disposed, said drum having generally vertical end walls and a peripheral wall extending around at least a major portion of the periphery of said end walls, a reel having its axis horizontally disposed and mounted on said support for rotation within the drum about said horizontal axis, said reel having work supporting means arranged around the periphery thereof so that when it is rotated, the work pieces are moved in a circular path downwardly through the polishing media in the drum and then upwardly out of the polishing media, said reel having spindles at the opposite ends thereof by means of which it is supported, said endwalls haying vertically elongated openings therein through whichsaid spindles project, said openings extending upwardly from adjacent the longitudinal axis of the drum toward the upper ends of said end walls and means for lowering said drum from a position wherein the longitudinal axis of the drum and the longitudinal axis of the reel are disposed generally at the same level to a position wherein the longitudinal axis of the drum is disposed at a level substantially below the longitudinal axis of the reel.

13. A machine as called for in claim 12 including means for rotating said reel while the drum is being raised and lowered.

14. A machine as called for in claim 13 wherein the peripheral wall of the'drum extends around at least the lower half portion of the end walls with the opposite ends thereof spaced apart at the upper portion of the drum to define an opening therein, a cover for closing said opening, said cover being hinged to the drum for movement from a position overlying the opening to a position disposed out of the vertical projection of said reel, said reel being removably mounted within said drum.

15. A machine as called for in claim 14 wherein said spindles each comprise at least two portions, one portion providing a chuck for the other portion, one of said portions being fixed on the reel and the other portion being journalled for rotation on said support.

16. A machine as called for in claim 15 wherein each chuck includes separable members which, when separated, enable removal of the other portion of each spindle in a direction radially of the chucks.

17. A machine for polishing work pieces comprising a generally cylindrical hollow drum having its longitudinal axis extending horizontally, a reel arranged in said drum for rotation about a horizontal axis, means for rotating said reel about said horizontal axis, said reel having around the periphery thereof means extending obliquely to the horizontal axis of the reel and obliquely to the radial plane of the reel so that when the reel is rotated, said means impart turbulence to said media.

18. A machine as called for in claim 17 wherein said last mentioned means comprise bafiie plates.

References Cited in the file of this patent UNITED STATES PATENTS 502,760 Rechtsteiner Aug. 8, 1893 512,312 Morgan c Jan. 9, 1894 961,523 Nichols]; June 14, 1910 1,131,119 Crandall Mar. 9, 1915 1,310,071 Gurry July 15, 1919 1,452,093 Pollack Apr. 17, 1923 1,512,350 McCorkle et al Oct. 21, 1924 1,605,179 Forster Nov. 2, 1926 1,624,783 Fisher Apr. 12, 1927 2,494,733 Whitehead Jan. 17, 1950 2,545,291 Lupo Mar. 13, 1951 2,700,254 Kinker et al. Jan. 25, 1955 FOREIGN PATENTS 1,028,777 France May 27, 1953

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