US2855730A

US2855730A - Methods and apparatus for producing decorative finishes on articles

Info

Publication number: US2855730A
Application number: US607489A
Authority: US
Inventors: John E Ferguson
Original assignee: Risdon Manufacturing Co
Current assignee: Risdon Manufacturing Co
Priority date: 1956-08-31
Filing date: 1956-08-31
Publication date: 1958-10-14
Anticipated expiration: 1975-10-14

Description

Oct. 14, 1958 Filed Aug. 51, 1956 J. E. FERGUSON METHODS AND APPARATUS FOR PRODUCING DECORATIVE FINISHES ON ARTICLES 5 Sheets-Sheet 1 INVENTOR JOHN E. FERGUSON l M ATTORNEYS.

Oct. 14, 1958 J. E. FERGUSON f 2,855,730

METHODS AND APPARATUS FOR PRODUCING DECORATIVE FINISHES ON ARTICLES Filed Aug. 31, 1956 5 Sheets-Sheet 2 a l *LA/f JNVENTOR /tzg 2 JOHN E. FERGUSo/v A@ Tram/EY.;

OC- 14, 1958 J. E. FERGUSON 2,855,730

METHODS AND APPARATUS FOR PRODUCING DECORATIVE FINIsaEs on ARTICLES Filed Aug. 31, 1956 5 Sheets-Sheet 3 1N V EN TOR JOHN E. FERGUSON Oct. 14, 1958 J. E. FERGUSON 2,855,730

'- METHODS AND APPARATUS Foa PRonucTNG DECORATIVE FINTsHTs oN ARTICLES Filed Au'g. s1, 195e 5 sheets-sheet 4 4a u Y/ INVENToR /'lgg B`Y JoH/v E. FERGuso/v Www/dwz@ l MATTORNEYT.

Oct. 14, 1958 J. E. FERGUSON 2,855,730

METHoDs AND APPARATUS FOR PRoDucING DECORATIVE v FINISHES oN ARTICLES Filed Aug. :51, 195s 5 sheets-sheet 5 za 30 Z6 INVENTOR JOHN E. FERGUSON A ATTORNEYS'.

United States Patent f METHODS AND APPARATUS FOR PRODUCING DECORATIVE F INISHES N ARTICLES John E. Ferguson, Southbury, Conn., assigner to The l Risdon Manufacturing Company, Naugaluck, Conn.,

a corporation 0f Connecticut Application August 31, 1956, Serial No. 607,489

Claims. (Cl. 51-145) This invention relates to methods and means for producing decorative finishes on the surface of articles, and it relates more particularly to the production of such finishes using semi-automatic apparatus capable of applying the finish rapidly and on a large scale. A

It is common practice to use a standard grinding machine for finishing metal articles, more particularly metal castings or other more or less roughly finished products,

the part travels along a predetermined path on the conveyor.

One object of the present invention is to employ a similar arrangement whereby a decorative finish is produced on the articles by using a grinding tool, whether a belt or a wheel, to cut closely spaced parallel vlines in the surface of the article rather than to grind down the surface thereof in order to remove a desired amount of metal or to render it smoother. In other words, the grinding machine is not used for grinding the work in the ordinary sense but to provide a relatively rough surface or pattern in which the marks or cuts therein are arranged in predetermined directions to give the surface a textured appearance. A more specific object of the invention is to apply such decorative finish to articles which are generally cylindrical in shape.

In.thus producing a decorative finish of this nature, a certain amount of material is necessarily ground off the surface of the object being decorated. An important object of the invention is to apply a grinding tool uniformly over the desired surface so that the surface is not ground down more at one point than at another.

Another specific object of the invention is to provide a criss-cross nish consisting of such above-mentioned closely spaced parallelv cuts, across which are ground similar cuts giving the surface the appearance of a coarse weave in a piece of fabric.

A further and general object is to provide semi-automatic apparatus for applying such decorative finishes which is simple, durable, and economical in both costL and construction as well as operation.

These and other objects of the invention, as well as novel features and advantages, will become further apparent from the description hereinafter.

According to one aspect of the invention, generally cylindrically shaped articles on which the decorative finish is to be ground are carried in a line on work holding members mounted on a continuously moving conveyor, the articles being brought by the conveyor one after another Ainto engagement with the grinding or working Surface of a grinding machine and resiliently h eld against sesam Patented Oct. i4, 19.58

such grinding surface during the grinding operation. In addition, in order to prevent the article from being spun too rapidly by the grinding machine, a braking pressure is applied either to the article itself or to the member upon which it may be fastened in case such member, rather than the article itself, is rotatable. The action of the abrasive grinding tool on` the resiliently mounted article, together with the braking action against rotation of the article, causes the article to bounce or chatter against the tool providing the desired texturelike finish in the surface being marked.

Another and important feature of the invention is the manner in which the articles or work pieces are brought into contact with the working face of the grinding tool. As will be more apparent hereinafter where reference is made to certain specific embodimentsV and applications of the invention, it is highly desirable that the full length of the work piece be in contact with the grinding surface during the entire marking operation, in order to avoid any variation in the force exerted at dierent places on the surface of the piece while in contact with the grinder. Obviously, if the force urging the work piece against the grinderis all exerted at one point on the surface of the piece, the surface at that point will be ground more than if such engaging force is spread over the full length of the work piece. Such uneven grinding isavoided in the present instance by 'moving the workpiece into contact with the grinding tool at a point in its travelwhere it will engage the grinding tool along the full length of the surface to be ground, and then by moving the work away from the grinding tool after the surface of the article has been provided with the desired marking' and while it is still in full contact with the tool. For example, where the grinding wheel or belt is set to produce cuts in the surface of the Work running at an angle to the length thereof, the work approaches the belt at an angle to the direction in which the belt is travelling; and if the work is permitted to engage the edge thereof, Ait -wouldbe in grinding Contact at only one point on its surface. This point of Contact, therefore, would receive the full force which urges the work into engagement with the 'grinding belt and would accordingly be ground down more, or at least marked more heavily, than the mid-portion of the work where that force is distributed over the full length of the surface being marked. An advantage of the present invention, therefore, is that the articles which, so far as this particular aspect of the invention is concerned, could have flat surfaces as well as curved, are ground evenly throughout, due to the fact that uniform contact is made with the grinding tool at all times.

In a specific application of a method employing features of the invention, a cylindrically shaped article or shell is mounted on a spindle so as to permit it to rotate about its longitudinal axis and is then carried by the spindle into contact with a grinding tool which travels in a direction at an angle to said longitudinal axis of the article, so that when the article is brought into working engagement with the tool, it is rotated by the tool as it is being marked. While the article is being ground by the grinding tool, it is resiliently heldin engagement therewith causing the tool to produce closely spaced cuts or interrupted scratch lines in the surface of the article in the direction in which the tool is travelling with respect to the article. At the same time, a braking pressure is applied to the article in order to keep its speed of rotation below the speed at which the grinding tool is travelling, this being necessary in order to mark the surface of the article properly.

Qne type of apparatus embodying certain features of 1 method of the invention, comprises one or more grinding machines positioned along the path of the conveyor so that the conveyor carries the pieces of work which are mounted thereon V'into engagement with `the working portion of the grinding machine, and Vresilient means urging the work into contact with the grinding machine so as to 'produce parallel cuts 'or scratches lin lthe 'surface of the work, the work pieces being generally cylindrically shaped and mounted on spindles on the conveyor for rotation about their major axes so that they are rotated by the grinding machine 4while in Contact therewith in order to apply the desired finish uniformly over the cylindrical surface of the articles.

In explaining further the nature of the apparatus for producing the decorative finish, reference will be made to the accompanying drawings which illustrate, by way of concrete example, certain desirable embodiments thereof. -In the drawings,

'Fig 1 is a more or less diagrammatic view showing a general arrangement of apparatus embodying n the invention;

' Fig. 2 is a front elevation of a grinding machine comprising a part of the apparatus;

Fig. 3 -is a fragmentary view of the apparatus in vertical section takenon line 3-3 of Fig. 2;

Fig. 4 is a View taken on the line 4 4 in Fig. 3 showing the rotary work supporting table and path of travel of the work `pieces along which they are moved into and vout of engagement with the grinding belt;

Fig. .S isa horizontal section taken on line 5 5 in Fig. 3 andshowing theposition of the working section of the grinding belt relative kto the work and to the camming means for bringing the work into engagement therewith;

LFig. 6 is an elevation, -partly broken away, of the rotary supporting table or conveyor;

Fig. 7 is a detailed View of a spindle supporting band shown in Fig. 6;

Fig. 8 is a detailed view, partly in section and on a somewhat larger scale, of one of the spindles on which the work is held;

Figs. 9 and 10 are perspective views of finished articles provided with decorative finishesin accordance with the present invention;

Fig. l1 is a view similar to Fig. 8 showing part of a modified form of spindlewhich may be used in place of the spindle shown in Fig. 8; and

Fig. l2 is a '.section taken on the line 12-12 of Fig. 11.

While the vimportant features of the invention are advantageous in connection with an apparatus having only one grinding head which is capable of producing a decorative finish having lines running only in one direction, two grinding heads may be used where it is desired to produce a criss-cross design. The apparatus specifically shown and described herein is designed to produce such criss-cross finish and, in order to save time and labor, employs two grinding heads. One head is placed so that its grinding belt travels at a desired angle to the work in order to cut lines in that direction, and the other head is placed so that its belt travels in a direction such that the lines are cut across those already produced by the first grinding head.

This vgeneral arrangement is illustrated more .or less diagrammatically in'Fig. 1,whic`h shows a horizontally disposed, circularly arranged conveyor table A, from the periphery of which projects a plurality of workholding spindles 10. Conveyors of this typemay carry as many as a hundred spindles spaced closely together on the periphery thereof. Cylindrically shaped pieces of Work w, which may be for instance the base or cover shells for lipstick'containers and similar articles, are placed-on the ends of spindles 10 by an operator or by machine using a hopper (not shown) at a loadingstationadjacent the periphery of the conveyor table f 4 A. When the apparatus is in operation, table A is rotated in a counterclockwise direction, as viewed in Fig. 1, at a uniform speed by a motor drive shown in Fig. 6, as will be more fully described hereinafter. The spindles 10 follow a circular path under an abrasive belt 12 of a grinding machine or grinding head B positioned adjacent the periphery of table A and extending over :the spindles 10 ,as :shown in Fig. l. AAs each spindle passes over the belt 12, the 'Wolk Ipiece yw on the end of lthe spindle is brought into engagement with the belt in order to produce scratches or cuts thereon running in one direction. An abrasive fbe'lt having a relatively coarse grit, on the order of grain size 24 to 36, may be used in order to .provide the desired finish. A Abrasive belts manufactured by Minnesota Mining and Manufacturing Company known as Three-M-Ite Resin Bond have been used to advantage, but various other types of abrasive belts can be employed in order to produce different effects inthe finish which is applied. For instance, 1if it is desired to produce a soft, more satinlike finish, a 36 grain belt can be used to apply an initial finish Von the article, and then this finish touched lightly with a smoothing 'belt of a much finer grit such as grain 220.

In the particular apparatus shown in the drawings,

the lines of the finish are applied at an acute angle to the longitudinal axis of the work piece and, therefore, the'belt of the grinding head B is set so that it travels at an angle of, for example, 45. On the other hand, it will be appreciated that if it is desired to run the lines-of the decorative finish -in a direction perpendicular to the longitudinal axis of each work piece w, the grinding vhead may be set so that the belt runs tangentially of the periphery of rotary table A along the path of kthe work fpieces.

However, where it is desired to apply a cross-cross pattern with the lines running diagonally across the article, the belt 12 is set at an acute angle to the work pieces w as shown in Fig. 1. Then, after this initial finish has been applied to the articles, cross lines or scratches are superimposed over the first cuts by bringing the work pieces into engagement with a second grinding head C located farther around the periphery of the conveyor table A in the direction in which it moves. Grinding head C is generally the same as the head B, except that its abrasive belt 12 is set to cut across the lines already applied to the work. A crisscross pattern produced in this manner is shown in Fig. 9 in which .the grinding belts are set to produce cuts at 45 to the longitudinal axis of the article and at 90 to each other. An abrasive belt of grain 24 for making both .cuts gives a very desirable criss-cross finish.

.After the cross cuts are produced on the work pieces by Ameans of grinding head C, the pieces are removed from spindles 10 by an operator as they pass an unloading station adjacent the Iperiphery of conveyor A as indicated in Fig. 1. Apparatus as disclosed herein, in which the work is carried along a `circular path about 66 inches in diameter, may operate at a rate of about pieces per minute. It will of course be readily understood by those skilled in the art that in addition to grinding the articlestas outlined above, yany portion or all of each article can be polished or buffed at desired points around the periphery of the conveyor. For-instance, if it is desired to polish the ends of cup-shaped articles, a standard buffing machine (not shown) can Vbe placed adjacent the periphery of table A on either side of the grinding heads B and C, with-the bufling wheels located so that they are in polishing contact with the ends of the work pieces w. However, where the criss-cross finish is applied, itisnot good practice, for reasons which will become apparent hereinafter, to polish the ends of the pieces before the decorative finish is applied to the cylindrical portion ofthe pieces. Moreover, it is sometimes desirable to `apply acsmoothing grind over a finish such asthat which may'beappled by either oftgrinding heads B or C in order to tone down the harsh appearance of the iinish as first applied. Thus, another grinding head in addition to those specifically Shown may be used in order to obtain the desired result in the appearance of the finished surface.

Referring now more particularly to Fig. 6, the conveyor table A comprises a hollow base 14, on the top of which is rotatably supported a horizontally disposed ring 16 driven through a central drive shaft 18 and gear box 20 by motor 22, gear box 20 being driven by the motor through a belt and pulley arrangement indicated at 24. As is apparent in the drawing, the drive means for the ring 16 is completely housed within the base 14 of conveyor table A. A series of holes 26 are drilled radially through ring 16, and shanks 28 are secured in each of holes 26 by means of set screws 30 (Fig. 8).

A central passage 32 is drilled in the outer end of each shank 28 for the reception of the inner end of portion 34 of a spindle 1t). The end of portion 34 of spindle 10 is tapered inwardly from its inner end to form a frustoconically shaped section, the large diameter of which is substantially equal to the diameter of passage 32 in shank 28 and the tapered portion 34 being long enough to extend somewhat out beyond the end of shank 28 to permit limited pivotal movement of spindle 10 with respect thereto. A pivot pin 36 is driven horizontally through holes on opposite sides of shank 28 and through a hole 37 at the large end of the tapered portion 34 in spindle 1t) to retain the spindle in shank 28 while permitting it to pivot vertically. If it is desired to make the spindles 10 rotatable while at the same time allow them to pivot vertically for reasons which will become more apparent hereinafter, the shank 28 may be rotatably mounted in bearings 29 within the ring 16 as shown in Fig. 11. In

order that the spindle 10 may pivot vertically while it4 is rotating, the hole 37 in spindle 10, through which pivot pin 36 extends, is tapered on both sidestowards the middle as shown in Fig. 12, thus allowing the spindle to pivot longitudinally of pin 36 as well as transversely.

In order to prevent foreign matter from working in between the end portion 34 of spindles 10 and the Shanks 28 within which they are pivoted, a flexible cover 3S of tubular rubber or fabric material is provided on each spindle, one end of said cover being suitably fastened t shank 28 with the other end fitting snugly around spindle 10, as shown in Fig. 8. The outer end of spindle is provided with a somewhat enlarged cylindrical portion 40 on which the'work pieces w t relatively loosely so that they may rotate thereon. Work pieces w are of generally cylindrical shape but may be slightly tapered as shown in Figs. 3, 8 and 9 or even rounded somewhat if desired. Such odd shapes, even though not perfectly cylindrical, will lie substantially flat against -a grinding belt due to the fact that portion 40 of the spindle is of smaller diameter than the inside of the work piece w permitting the work piece to continuously adjust itself upon its spindle into full contact with the grinding belt as shown in Fig. 3.

Spindles 10 are made to pivot vertically so that they can be lowered under the edge of the grinding belt as shown in Fig. 4 and then raised up again in a manner to be described, in order to bring the shells w into contact with the underside of the belt. In order to prevent the work pieces from dropping off the spindles, the outer ends of spindles 10 are held in a slightly raised position, as shown in Fig. 6, by a supporting ring or band 42 which surrounds the spindle mounting ring 16 of conveyor table A and is spaced therefrom so that the mid-sections of spindles itl rest on the upper edge of band 42. Braces 44 extend downward from band 42 and may be conveniently fastened to the stationary base 14 of the conveyor in order to supportv band 42. As the ring 16 of table A rotates, the outer end of spindles 10 are supported by band 42 and slide horizontally along it. In order to permit spindles 10 to pivot down so as to clear the grinding machines, the upper edge of band 42 is recessed as 6, at 46 (Fig. 4 and 7) along a predetermined length of a section thereof, the recess 46 being positioned directly in front of grinding head B. An inclined camming surface 48 at one end of recess 46 permits each spindle to drop down just before it reaches the grinding belt 12. The

inclined surface 50 at the other end of recess 46 raises the spindles back upto their normal slightly upwardly inclined position after they move out from under the grinding head. In the apparatus here described a second recess 46 is provided in band 42 adjacent the other grinding machine C.

The grinding heads B and C may be of any suitable type capable of handling an abrasive belt which is wide enough to handle the surface on which the finish is to be applied, taking into account the angle at which the lines are to be cut with respect to the work piece. As has already been mentioned hereinabove, both grinding machines are basically the same construction, and a description of one will sufce for both. Thus, a typical grinding head adapted for use with the present apparatus is shown in Fig. 2 and includes head plate 52 rigidly mounted on a base 54 so that it projects forwardly thereof. Head plate 52 carries a drive pulley 56 and two horizontally disposed guide wheels 58 located below and to either side of pulley 56 on adjusting arms 60 mounted on head plate 52. The abrasive belt 12 is trained around pulley 56, wheels 58 and a take-up pulley 61 with the abrasive side of the belt facing outward. The horizontal stretch of belt 12 between wheels 58 forms the working surface of the grinding'machine and is offset both forwardly and laterally of base 54 suitable distances so that it can be positioned over the ends of spindles 10 on conveyor table A at virtually any desired angle as shown in Fig. l. Where the machine is used to produce a crisscross iinish on an article which is 1% inches long, abelt 6 inches wide should be used to provide suiiicient grinding area due to the fact that the work moves transversely across the belt. On the other hand, where the belt is set at right angles to the length of the article, a 2 inch belt is sufiicient for the same size article. Either belt when used on the type of grinding head s hown may be 132 inches long, which is 4standard for this particular machine. The belt is driven in either direction at relatively high speed by a motor mounted on the rear side of head plate 52 behind pulley 56. The grinding head thus far described is a commercially available piece of apparatus manufactured by the Packer Machine Company of Meriden, Connecticut. Other suitable grinding heads can be used if desired.

It will be noted from Fig. 1 that both the grinding belts 12 and 12' of grinding heads B and C travel in a direction inwardly toward the center of the conveyor table A so that when the work pieces w come into contact with the grinding belts, they are forced inwardly onto their spindles 16 rather than outwardly, thereby preventing them from dropping otf accidentally as they are being ground. Consequently, the belt 12 of grinding head C travels in the opposite direction from that of head B when viewing these machines from the front. However, it will be appreciated that the relative angular positions of the grinding heads B and C with respect to the work pieces can be reversed if desired, in which event the direction of the respective grinding belts will also be reversed.

While the belt 12 hasbeen described hereinbefore as travelling horizontally between guide wheels 5S, actually only a relatively short central section of the belt runs perfectly horizontally, this section being guided by a backing plate 62\,v/hich is vertically adjustably mounted adjacent the lower edge of hea-d plate 52. The undersurface of plate 62, against which the belt 12 rides, is located somewhat below wheels 58 so that the belt slopes upwardly on either side of plate 62 for a reason which will become apparent hereinafter. Plate 62 is of a depth at least equal to the width of belt 12, as shown in Fig. 3, and is of suicient width to provide adequate space for engagement of the grinding belt by the work pieces as they move on conveyor A. Where the surface being ground does not present a perfectly straight-line contact with the grinding belt but bends slightly as in the case of the article w illustrated in Fig. 3, in which a short portion of the shell at its open end is cylindrical while the remainder of the article tapers outwardly to form a frusto-conical portion, the irregularity in the surface can be compensated for by providing a slight depression 63 in the underside of plate 62 conforming with the shape of the article. Since the grinding belt 12 tits taughtly against the underside of plate 62 and is relatively exible, it conforms with depression 63. This permits the truste-conical portion of the article to lie flat against and to skid and roll along the horizontal section of belt l2 on the undersurface of plate 62, while the cylindrical portion of the article lits up into depression 63 so that both portions are ground evenly and a uniform pattern is applied throughout.

At the rear edge of lbacking plate 62 is provided a vertical mounting piece 63, through which are eut a pair of spaced, vertically elongated holes 64, which receive bolts 66 for adjustably fastening the backing plate 62 in place. A pair of vertically extending spacer bars or tracks 68 are provided on the face of head plate 52 on either side of bolts 66 so that the mounting piece 63 is drawn into rigid engagement with bars 66 when bolts 66 are tightened.

On the rear side of the head plate 52 of the grinding machine (Fig. 3) is mounted an L-shaped vbracket 70, which is also secured to plate 52 by means of bolts 66, the threaded ends of which extend through plate 52. The vertical leg of bracket 70 is provided with elongated holes 72 through which the threaded ends of bolts 66 project in order to provide vertical adjustment for bracket 70. Nuts 74 are threaded to the ends of bolts 66 and, when tightened down, secure both the backing plate 62 and bracket 70 in adjusted positions. The horizontal leg of bracket 70 projects forwardly under the bottom edge of head plate 52 and partially under the grinding belt 12 in spaced relation thereto. A resilient brake member or shoe 76 is mounted on the upper surface of the horizontal leg of bracket 76 in a position where it will be engaged by the ends of the work pieces w during the grinding operation, in order to prevent the work from being rotated too rapidly by the grinding belt i2. Brake shoe 76 consists of a curved angle iron 7S, the front face of the vertical leg of which is lined with a resilient material 80, such as sponge rubber, over which is secured a flexible sheet metal facing 82, as shown best in Figs. 3 and 5.

The lining 30, 82 of the brake shoe '76 is fastened to the angle iron 78 at either end thereof by means of screws 83. As thus shown in Fig. 5, brake shoe 76 is angular-ly mounted on bracket 70 so that it will be properly positioned for engagement by the ends of work pieces w. To this end, the horizontal leg of angle iron 73 is provided with a plurality of elongated slots 66 through which bolts S2 are passed and threaded into bracket 76. Slots 86 permit limited angular adjustment, as well as forward and back adjustment, of brake shoe 76 relative to spindles and work pieces w. lf the angle at which the grinding belt 12 is placed with respect to the work is changed to any great extent, the brake shoe '76 can be adjusted proportionately by simply tapping new holes in bracket '70 for bolts 84.

Engagement of the ends of the work pieces w on their spindles 10 with the facing S2, when. the brake shoe 76 is properly adjusted, causes the face of the shoe to bow inwardly while applying a resilient frictional force against rotation of the work pieces. The sheet metal strip S2 is preferably chromium plated on the side which is engaged by the work pieces in order to provide a long wearing, smooth surface which will not scratch the ends of the work pieces,

In addition to its primary function as a brake against excessive speed of rotation of the work pieces, the member 76 also helps to hold the work pieces on their spindles llt) just before and after the work pieces are brought into contact with the grinding belt. As has already been mentioned hereinabove the ends of the spindles are normally carried in a slightly raised position in order to keep the work pieces from falling olf. However, at the point where the spindles are permitted to drop down under the edge of the grinding belt, it is possible that the work pieces may fall off the spindles during the short period of travel before they are brought into engagement with the grinding belt 12. It will be note-d, however, that just as each spindle 10 drops down on the inclined surface 4S into recess 46 on support band 42, the end of the work piece comes into contact with the facing 82 of brake shoe 76, thereby preventing the work piece from jarring off. Moreover, the work pieces remain in contact with the brake shoe 76 until they are again raised to their normal upwardly inclined position lby the camming surface 50 at the other end of recess 46.

As has already been mentioned generally hereinbefore, an important aspect of the present invention is in providing a uniform texture-like pattern Ion the surface of various kinds of articles, such as the items shown in Figs. 9 and l0, which are covers or bases for lipstick containers. Such finishes or patterns are produced by making the work bounce or chatter against the belt as it is being ground, causing interrupted parallel lines or cuts of various lengths and depths in the surface of the work. In o-rder to permit such chattering action, a constant resilient upward force is applied to spindle it) while the work is in contact with the grinding belt. It is a natural tendency for a grinding belt to drive the work piece away from it upon contact therewith. Consequently, in ordinary grinding operations, the work piece is held rigidly to prevent it from chattering during the grinding operation. The coarser the grit of the belt, the greater is the tendency for the work to bounce on the belt. Furthermore, the lighter the force is holding the work in engagement with the belt, the more it will bounce. Another factor which causes the work to jump and chatter as it is being ground is the use of a hard backing plate such as the plate 62 hereinabove described. The texture of the pattern which is applied is thus greatly affected by the degree of bounce or chatter of the work against the grinding belt. ln addition, different effects can be produced by changing the speed at which the belt travels. For instance, in producing a criss-cross pattern such as that shown on the article illustrated in Fig. 9, the speed of the belt may be on the order of 3200 feet per minute, while the speed of the belt used to produce the pattern on the article shown in Fig. l0 was about 4500 feet minute. Moreover, the belt used in producing the horizontal pattern shown in Fig. 10 was of a finer grit and the amount of bounce during grinding was reduced by providing a resilient backing for the belt in place of the rigid plate 62 of the apparatus specifically illustrated in the drawings. It will be apparent from the foregoing that there are many ways of providing different results in the finish but, in any event, a fundamental requirement is that the work be held resiliently, rather than rigidly, in engagement with the grinding belt in order to make the work jump and chatter against the grinding belt in what has been aptly termed clobbering of the surface of the work.

Referring again to Figs. 3 and 4, the means for raising and holding the work in contact with the grinding belt 12 consists of a cam plate 90 located between the spindle supporting band 42 and the outer ends of spindles 10. Cam plate 9i) has inclined end surfaces 92, 93 by which the spindles are raised and lowered as they are carried by the conveyor A into and out of engagement with the lifting cam. The top of cam plate provides a fiat surface of predetermined length selected so as to ensure vbe on the order of 4 inches.

grinding of the'entre cylindrical surface of the work While avoiding excessive and unnecessary grindingY there- For example, where a surface decoration is produced on a lipstick container such as that shown in Figs. 9 and l0, which isv about 5/8 in diameter, it has been found that the distance through which the work w should move horizontally when it is in contact with belt 12, as indicated by the stippled area g in Fig. 5, should Therefore, the top of cam plate 90 between the camming surfaces 92, 93 should be of corresponding length.

Cam plate 90 is mounted on a pair of vertical rods 94 guided within hollow posts 95 of a rectangualr framework 98 ,held between horizontal brackets 99 attached to the base 54 of the grinding head. An air cylinder 96 is supported in frame 98 so that its plunger 97 engages the underside of cam plate 90 urging it upwardly. A suitable air connection 100 is provided at the bottom of cylinder 96 to supply air under pressure thereto. In the specific apparatus herein disclosed, the air cylinder 96 has an effective diameter of 2 inches and is supplied with air under pressure at about 10 to 20 pounds per square inch, depending on how harshly the surface is to be ground. For instance, a very pleasing criss-cross finish can be obtained by using from l5 to 20- pounds pressure on the air cylinder 96 on the grinding head B in order to produce the closely spaced parallel cuts s (Fig. 9) which extend diagonally `downward from left to right and cover the entire surface of the shell, forming a kind of background over which the cross cuts x are applied by the grinding head C. A pressure of about 10 pounds is used in the air cylinder of grinding head C so that the cross linesappear in bunches spaced apart at relatively Wide intervals. This clearly demonstrates the manner in which the work is made to bounce away from the belt farther by reducing the pressure applied to the work, thus causing less frequent contact of the work with the belt.

`As may be seen in Fig. 4 and in Fig. 5 in which the position' of grinding belt 12 and backing 'plate 62 is indicated in broken lines for the sake of clarity, the spindles 10 reach the inclined surface 48 of the supporting band 42 just before the work pieces w come to the edge of the belt 12 of the grinding machine, causing the spindles and work pieces to drop down slightly in order to avoid contact with the edge of the belt. At this point the end of the work piece engages the metal facing 82 of brake 76 so that it can not. drop off the end of the spindle. Further movement of the work piece along its path of travel brings it into engagement with cam 90, whereupon it is raised into contact along its entire length with belt 12 asit reaches the position of the Work piece w'. Contact with the grinding belt causes the work l piece to rotate and at the same time to jump and chatter producing the desired decorative finish in the manner already described. When the work piecev reaches the position w" Where it is still in full contact with the grinding belt, it is permitted to drop down again out of contact with belt 12 as spindle 10 rides down the surface 93 of cam 90. Further movement of the spindle brings the work out from under the edge of the grinding belt and into engagement with the camming surface 50 on band 42 which raises it back into its elevated position.

By thus avoiding contact between the work pieces and either edge of the grinding belt, the surface of the work is ground evenly thereby producing a uniform finish. If, on the other hand, the work was permitted to Contact the edges of the belt, it will be readily understood that the initial contact would be at only one end of the cylindrical work piece so that all the pressure exerted by earn 90 would be concentrated at this point. This would of course 'cause the work to be ground more at its ends where the upward force exerted on spindles 10 by air cylinder 96 is concentracted on a smaller area than it is in the mid-portion of the work where the same force is distributed along the full length of the surface to be 1G ground. It is, therefore, extremely important to avoid a situation `of this kind, particularly where as in the present instance, the abrasive belts used are of such coarse grit thateven slight variations in the finish become very apparent.

Furthermore, it will be readily apparent from the foregoing that the cam plate provides means for accurately controlling the amount of contact of the work with the grinding belt. Thus, by simply providing a cam plate, having a shorter or longer horizontal upper surface, the total area of contact g (Fig.` 5) can be reduced or in- .creased correspondingly. This provides positive means for controlling the amount of grinding and the quality of the pattern produced, which is extremely critical when using harsh grindingbelts and high speed yapparatus capable of applying the finish rapidly and effectively.

It will be noted that due to the raised position of the wheels 58 of the grinding machine relative to the backing plate .62, as best seen `in Fig 2, the spindles 10 may pass under them without contacting the grinding belt, thus permitting the spindles to remain in their elevated positions until just before the work pieces reach the edge of belt where it engages the plate 62. Consequently, the period during which the spindles drop down to a position where the work pieces may tend to fall off is reduced to a minimum.

Various changes within the scope vof the present in-` vention can be made in the apparatus herein described. For example, a chain conveyor or belt which carries the work in a vstraight path could be used in place of the rotary conveyor table, if desired. Furthermore, the air cylinder 96 could be replaced by a suitable compression spring mounted in such a way that it can be adjusted to exert the desired force on the spindles. While reference has been made specifically to the application of decorative finishes on metal articles more particularly, it is conceivable that the same type of finish can be produced on other hard machineable materials such as plastic and the like. Moreover, particularly where it is desired to produce a smoother finish, such as that shown on the article illustrated in Fig. 10, a brake resiliently applied to the cylindrical surface of the article can be used in place of the brake 76.

What is claimed is:

1. ln an apparatus for producing surface ornamentation on a generally cylindrical article, the combination of a plurality of spindles each pivotally mounted on `a conveyor and having a portion adapted to hold such article for rotation about its longitudinal axis, a grinding tool located at a point along the path of said spindles adjacent their article holding portions, said grinding tool having a working surface adapted and arranged to travel in a direction at an angle to the longitudinal axes of the articles for marking their surfaces and for simultaneously rotating them about their axis, and resilient means adiacent said grinding tool having a cam plate located for yielding engagement by said spindles as they are carried to a position adjacent said grinding tool, whereby each of said spindles is pivoted by said cam plate toward said grinding tool bringing the article mounted thereon into engagement with the working surface of said grinding tool.

2. Apparatus as defined in claim l, wherein said conveyor is a horizontally rotating table capable of carrying a plurality of said spindles extending radially therefrom, the article holding portions of said spindles being located at the outer extremities thereof, and wherein said cam plate is mounted inwardly of the ends of said spindles.

3. Apparatus as defined in claim 2, wherein said resilient means further comprises an air cylinder connected to said cam plate and urging the latter in a direction which moves said article into contact with said working surface.

4. Apparatus as delined in claim 2, which further includes brake means mounted outwardly of said spindles 11 for engagement with the outer ends of said articles in order to resist rotation of the articles during the grinding operation.

5. Apparatus as defined in claim 1, wherein said grinding tool comprises a machine having an endless abrasive belt, said working surface being a section of said belt which is located at a point along path of said spindles for -grinding engagement with said articles.

6. In apparatus for producing surface ornamentation on articles, the combination of a plurality of work-holding members pivotally mounted in spaced relation on a conveyor for successively carrying said articles along a predetermined path, a grindingmachine having its grinding surface llocated along said path for engagement by said articles, guide means against which said work-holding members are normally urged as they move along said path, resilient cam means located adjacent said grinding surface and having a camming surface with which said work-holding members are successively brought into engagement for moving said articles into Contact with said grinding surface at a point wholly within the margins thereof, said cam means having a dwell of predetermined length along which said work-holding members are moved while said articles are resiliently held by said cam means in engagement with said grinding surface, and means for yapplying a constant force to said cam means for resiliently holding said articles in contact with said grinding surface, said cam means having an end portion permitting said work-holding members to pivot away from said grinding surface at a point where the articles are still wholly within the margins of said grinding surface.

7. In apparatus for producing surface ornamentation on articles, the combination of a plurality of radially extending, circumferentially spaced, workholding spindles mounted on a horizontally rotating conveyor, each spindle being pivotally secured at one end to said conveyor and having means for holding a substantially cup-shaped article at its free end, spindle support means located below said spindles intermediate their ends for normally supporting the free ends of said spindles raised above the horizontal, grinding apparatus having a grinding belt extending horizontally across the path of said articles, said spindle support means having a portion located adjacent said grinding belt permitting said spindles to pivot downwardly below the level of said grinding belt so that the articles do not contact the edge thereof, and resilient cam means having a camming surface with which said `spindles are successively brought into engagement as they move on said conveyor for raising each of said spindles and bringing the articles thereon into contact with said belt intermediate the lateral edges thereof, said cam means having a flat upper surface along which said spindles are moved for holding said articles in contact with said belt for a predetermined distance along the path of the articles, the end of said fiat surface being so located that each spindle is permitted to drop down again while the article is in full engagement with a midportion of the grinding belt, said spindle support means being further provided with a camming surface located adjacent to, but displaced from, said grinding belt for raising the ends of said spindles to their normal elevated positions after they move from under said grinding belt.

8. Apparatus as defined in claim 7, which includes means for applying a constant upward force on said cam 12 means for resiliently holding said articles in contact with said grinding surface.

9. Apparatus as defined in claim 8, wherein said means for applying a force to said cam means comprises an air cylinder under constant pressure.

l0. Apparatus as defined in claim 7, wherein said spindle support means comprises a stationary circular band surrounding said rotary conveyor, said spindles being urged by gravity into contact with the upper edge of said band, said portion of said spindle support means permitting the said spindles to pivot downwardly comprising an inclined surface at one end of a recess in the upper edge of said band, while said camming surface for raising said spindles to their normal positions comprises the inclined surface at the opposite end of said recess.

ll. In an apparatus for producing surface ornamentation on generally cylindrical articles, the combination of a plurality of spindles each mounted at one end on a conveyor and having a portion at the free end adapted to hold such article for rotation about its longitudinal axis, a grinding tool located at a point along the path of said spindles adjacent said article holding portions, said grinding tool having a working surface adapted and arranged to travel in a direction at an angle to the longitudinal axis of each article for marking its surface and for simultaneously rotating it about said axis, resilient means adjacent said grinding tool urging each article successively laterally into engagement with said marking surface, and brake means located adjacent the ends of said spindles against which the ends of said articles are pressed in order to retard rotation of said articles during the marking operation.

l2. Apparatus as defined in claim ll, wherein said spindles are pivotally mounted on said conveyor in a substantially horizontal position, and which further includes support means engaging the under sides of said spindles intermediate their ends and normally holding the spindles raised above the horizontal at their outer ends, said support means having a recessed portion adjacent said grinding tool, one end of said recessed portion being located such that said spindles drop down under the edge of said working surface, the other end of said recessed portion being located such that said spindles are raised to their normal positions just as they emerge from under the working surface of said grinding tool.

13. Apparatus as defined in claim 12, wherein said brake means extends beyond both sides of said working surface of said grinding tool and is in close proximity with the ends of .the articles adjacent both ends of said recessed portion of said support means so as to prevent said articles from falling off their spindles while lowered to avoid contact with the edges of said working surface .of said grinding tool.

References Cited in the lile of this patent UNITED STATES PATENTS Hackman June 6, 1944 Glike May 22, 1945 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No., 2,855,730 October 14, 1958 J o bn E, Ferguson It is hereby certified that error appears in the printed specification of' the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 9, for "passes overH reed e passes under signed and Sealed this 31st day of March 1959.,

(SEAL) Attest:

KAEL E. AXLINE ROBERT C. WITSON Attesting Officer Commissioner o'. Patents