US2316518A

US2316518A - Rub-out machine

Info

Publication number: US2316518A
Authority: US
Publication date: 1943-04-13
Anticipated expiration: 1960-04-13

Description

April 13,1943. E. F. KLENKE, JR

RUB-OUT MACHINE Filed May 8; 1940 5 Sheets-Sheet 1 (en j [4/ "mmm INVENTOR Edzggzenmd i @z5-E April 13, 1943.

E. F. KLENKE, JR

RUB-OUT MACHINE Filed May 8, 1940 3 Sheets-Sheet 2 INVENTOR Edward Fllenkadn ATTOR EY 5 Sheets-Sheet 3 INVENToR /45 Edward F16' Zenedn BY f ,4 /uw ATToR E.. F. KLENKE, JR

RUB-OUT MACHINE Filed May 8. 1940 April 13, 1943.

Patented Apr. 1.3, 1943 UNITED- STATES PATENT oFFlcF.

9 Claims.

This invention relates to grinding apparatus and, more particularly, to devices of this kind forv mulling pigments or other solids into oil and other vehicles.

Dry pigment colors are generally purchased on y physical rather than chemical tests. While it is true that the exact chemical composition of a color may be desirable for certain uses, nevertheless, the value and suitability of colors for most purposes can be quickly evaluated by standard tests which comprise grinding the dry pigment into oil or other liquid vehicles and comparing them with standards prepared in a similar manner. Various methods of performing this grinding operation have been employed. When relatively large samples are to be tested, small scale mills of the commercial type may be used. However, amuch more rapid method of testing, one requiring only a relatively small sample-the socalled mulling or rub-out test-in which a predetermined quantity of pigment is mixed superflcially with a definite amount of oil or other suitable liquids and spreadl out on a glass slab for further treatment, is almost universally employed. In this testing procedure, the operator mulls the mixture of pigment and oil with a hand muller or other suitable implement by rubbing it back and forth over the glass slab on which the sample has been spread. The degree of mulling dependson a number of lvariable factors such, for example, as the amount of pressure exerted by the operator, the number of strokes, and the area covered. Furthermore, in order to get a uniformly mixed sample of approximately the same particle size, it is necessary to pick up the paste from the glass slab and spread it out for further mulling. In extreme cases,

this operation must be repeated several times before a uniformly fine product is obtained. It is obvious' that the personal element plays an important role in these tests, and the results are at best only empirical, even in those instances where a great deal of skill has been acquired by the operator. Identical operating conditions are, therefore. seldom, if ever, attained and exact duplication of results extremely unlikely.

Various mechanical means for eliminating the personal equation have been proposed. 'I'he usual devices of this kind have made use of a rotary plate of relatively large size on which the sample to be tested isplaced. The grinding action may be obtained by placing thereonanother flat plate which may act in a variety of ways. For instance, in U. S. Patent 2,150,603, dated March i4, 1939, and entitled Apparatus for mulling pigment,

the pigment and oil to be tested are placed on a stationary lower plate, and an upper plate of substantially the same size is made to rotate thereover at a constant speed. In another modi- 1 iication of the prior art mulling devices, a second plate of relatively smaller diameter is free to rotate about a -xed point offset from the center of a larger lower rotating plate, the rotation of said upper plate being provided by means of'friction between the two mulling surfaces. In still another modliication, a small grinding plate oi center from a larger lower rotating plate is driven in a circular motion at a constant speed.

All of these devices have certain elements of value and are capable of successful operation. Nevertheless, they have disadvantages which result in inefficient operation or make exact duplication of results impossible. For instance, in the device disclosed in U. S.l Patent 21,150,603, herein. before referred to, little or no mixing is obtained, and uneven grinding of the particles results. 'I'hose particles at or near the center receive little if any grinding action, while those at or near the periphery of the plates are ground exceedingly ne. Furthermore, those particles placed at or near the center tend to remain in their relative positions during the grinding operation. while those at or near the periphery maintain their relative positions throughout the entire grinding cycle. In order to overcome this objection, it is necessary to pick up the pigment, redistribute it on the plate, and repeat the mulling operation. In cases where extreme particle iineness is desired, it is necessary to repeat this operation several times.

In those devices employing a small off-center plate which either rotates by friction or by positive driving means, a limited amount of mixing as well asa grinding action is obtained. However, in all of these devices, there is a serious tendency to force the pigments or inks being milled out from under the oit-center plate where it is picked up on the edges of this plate and permanently removed from the ileld of grinding. This tendency to pull the ink away from the edges of the plate is due partly to the type of motion imparted tothe plates and their relative speeds. While beveling the edges of the oft-center plate tends to reduce the amount of pick-up somewhat, this objectionable feature cannot entirely be eliminated thereby.

It is an object of this invention to provide an improved mulling machine for grinding pigments or other solids into oil or other `vehicles so that duplication of results may be readily obtainable.

A further object is the provision of means for mulling these solids to a uniformly fine particle size. A still further object is the provision of means for permanently retaining the pigments or inks in the field off grinding. Other objects will be apparent from the description of the invention hereinafter given.

The above objects are accomplished according to the present invention by an apparatus comprising two rotatable plates having co-operating smooth grinding surfaces between which the materials may be placed for grinding and adapted to be moved into and out of contact with each other, means for positively rotating one of said plates, means for reciprocating the smooth surface of the other plate over the smooth surface of the positively rotating plate, and means for maintaining said smooth grinding surfaces in conta/ct with each other under a Apredetermined constant pressure.

More specifically, the invention provided in accordance with a, preferred embodiment of the present invention comprises a horizontally disposed lower mulling plate of circular cross-section, the upper surface of which has been ground smooth, mounted at the end of a rotatable shaft; means for imparting rotary motion to said shaft; a smaller upper fiat plate of circular cross-section 'with beveled edges, the lower surface of which has been ground smooth, disposed at the end of a reciprocating shaft and adapted to be moved into and out of contact with the smooth surface of conveniently constructed of any material such as metal or wood, so long as a substantially rigid structure is provided. Supported by the base I0 and the upright I2 by any convenient means are bearings I4, i4, and journaled and free to rotate which it is fitted, thus projecting somewhat above the outside edge of the lower mulling plate support I6. The upper surface of the plate is flat and ground uniformly smooth. The mulling plate may be made of glass, metal, lithographers stone, or other suitable materials. The plate is substantially in a horizontal position and centrally disposed with respect to the rotating shaft I5.

Attached to the underside of the supporting arm I3 by any convenient means are reciprocatthe said larger plate, said maller plate, when in ciprocate thereover; means for imparting recipi rocating motion to said smaller plate; means for stopping" the relative movement between the plates after a predetermined number of movements of said plates, and means for maintaining said smooth grinding surface of each plate in contact with each other under a predetermined constant pressure.

In the drawings, which show the preferred embodiments of the invention:

Figure 1 is a top plan view of one embodiment of my novel mulling machine:

Figure 2 is a front elevation of the machine shown in Figure l, partly in section;

Figure 3 is a top plan view of an alternative embodiment of an especially preferred mulling machine wherein the upper mulling plate oscillates over the smooth surface of the lower mulling plate in a straight path;

Figure 4 is a front elevation of the embodil ment shown in Figure 3, partly in section;

Figure' is a side elevation of the embodiment shown in Figure 3;

Figure 6 is a top plan view of an alternative embodiment of the mulling machine wherein the upper mulling plate oscillates over the s-mooth surface of the lower mulling plate in an arc of a circle;

Figure 'l is a front elevation of the machine 4shown in Figure 6, partly in section; and

Figure 8 is an enlarged detail of the oscillating mechanism for oscillating the upper mulling plate over the lower mulling plate.

Figs. 1 and 2, in which like reference characters denote similar and like parts, a base I0, right hand upright or standard I I, and left hand upright or standard I2 rigidly connected to the base, and a supporting arm I 3, pivotally connected to the upright II constitute the main framework of the machine. The framework may -be Cal ing rod supports I9, I9, having an opening 20 cut therein and into which is fitted a horizontally slidable reciprocating rod 2 I. Attached to the reclprocating rod in any convenient manner is collar 22 which fits over pin 23 with sufficient clearance to allow the pin to rotate within the collar but which prevents substantial vertical movement of the supporting arm I3 with respect to the -pin 23. The collar likewise provides a fixed center about which the pin is free to rotate.

An upper mulling plate support 24 with a circular recess 24 cut therein is suitably connected to the lower end of the pin 23. Mounted in the recess of the upper mulling plate support is an upper mulling plate 2l having a smaller diameter than the lower mulling plate but similarly constructed, except that the edges thereof should be beveled at an angle o f substantially 45, although if desired, both plates may .be beveled as shown. In the present embodiment of the invention, the lower surface of vthe upper mulling plate 21 is vertically and horizontally adjustable into and out of contact with the upper surface of the lower mulling plate I8 so as to completely expose the mulling surfaces of the mulling plates. This adjustment is provided to permit easy access to the mulling surfaces for placing the sample thereon and for removing same therefrom after the grinding action is completed. The supporting arm I3 is pivotally connected to a pivot pin -28 which is fastened rigidly to the top of the upright II substantially in the centerthereof. The supporting arm I3 is free to oscillate about the pin 28 in a horizontal plane, but vertical movement of said member about said pin is prohibited by any convenient means, such, for example, as by pin 29. Upward vertical adjustment of the supporting arm I3 is provided about pin 30 as a pivot. As a result of these adjustments, the lower surface of the upper mulling plate 21 is free to move into and out of contact with the upper surface of the lower mulling plate.

For centering the supporting arm I3 when in its operable position, a centering .pin support 3l, disposed near the top of the standard I2 having a bore 32 cut therein, is provided. The supporting arm I3 with centering pin 32a attached thereto at one end is free to engage in the bore 32, thus assuring the proper positioning of the upper 81Min mulling plate. It will be observed that the topv surface of the centering pain.y support 3| is 'substantially lower than the bottom surface of the supporting arm I2 when the mulling surfaces of v the mulling platesare in contact with each other In the embodiment of the invention herein described, a constant load on the mulling plates is applied by means of a weight 33 slidably mounted for adjustment on a beam 34, attached to the upper end of the-standard I2 by means of a hook or loop 3B. The beam rests on a fulcrum point SS which is suitably fastened to the top of the supporting arm i3. The load on the beam is transmitted to the top surface of the upper-mulling plate 21 through wheels 38, $8 positioned on shafts Il), journaled in supports di, GI attached to the underside of the supporting arm i3.v `The magnitude of the pressure can be variedfdepending on the position of the weight 33 on the beam 3d. The arm i3 and its associated parts yare conveniently horizontally adjustable in order that collar 22 may be placed over pin 23. The entire arm i3 pivots about pin 3l! and horizontally about pin 28. The hook 35 is adapted to engage beam 3d, the weight t@ upon the arm i3 being in adjusted position, to thereby secure its action through the fulcrum point 3b.

The reciprocating housing 1I is provided with grooved'fwheels 1l, 1I which fit on a runner -or guide Il attached securely to the under side of the adjustable arm support in any convenient manner, auch as by bolts 16, 16 (Fig. 3). guide or runner extends the entire width of the armv Support and is suitably shaped, as shown, to conform to the running surfaces of the grooved wheels 14 in order to prevent the wheels from becoming derailed from the runner. The construction provides a relatively simple means for reciprocating the upper mulling plate over lthe upper'surface of the lower mulling plate. The upper mulling plate .is vertically adjustable into and out of contact with the upper surface of the lower mulling plate, said adjustment being obtained by raising or lowering the supporting Rotary motion of the lower mulling plate, and

driven from a source of power not shown in the gdrawing. Reciprocating motion to the upper mulling plate may be obtained from the same or a separate source of power. Reciprocating motion of the upper mulling plate over thelower arm 6l, which is pivotaily connected to the base 60 -by shaft 11, 4journaled in

bearings

18, 18, supported in bearing' support 86, cast to base 30. The shaft 11 is substantially of smaller diameter than the opening in the supporting arm, thus leaving clearance between the shaft and the arm. The means for applying pressure to the mulling members is accomplished in a novel manner. Theisupporting arm 3i, which also acts as a beam, is provided with a handle di and a notch 82 which is free to engage a locking bar d3 supported by supporting members ed, se cast inte-` grally with the frame @63. The handle @i pivots about a fulcrum point dit located in the center of the supporting arm whereby the notch d2 can be caused to engage the bar @d in a locking mam ner when the mulling plates are locked into position. This action of the engaging notch and pin shifts the arm di about its /fulcrum 8b so that it no longer is in contact with the shaft plate in the embodiment herein described is obtained by miter gear it attached to jack shaft d@ through a ruiter gear 1 on the lower end of a shaft d8 journaled in bearing Et which is attached to the framework in any convenient manner. 'Wheel 5l with crank pin b2 rigidly secured to the upper side of the wheel substantially at its periphery ls suitably secured to the upper end of the shaft su. mciprocating motion to the reciprocating rod is provided by means of pin 52 which engages in a dog on yoke 53 of the reciprocating rod i3. Rotary motion of the upper mulling plate about the pin 23 is obtained by means of friction between the surfaces of the mulling members, and the relative rotary movement depends on the slippage.

Figs. 3, 4, and 5 show an alternative em-bodi- -ment of a mulling machine coming lwithin the present invention. A base t@ and supporting arm Si pivotally connected to the frame in any convenient manner constitutes the ma-in framework of the machine. A rotatable shaft B2 journaled in

bearings

63, 63 cast integrally with the frame Bil has suitably mounted at its upper end a lower mulling plate support 64 into which is fitted a lower mulling plate 55.

An upper mulling plate 66 is suitably mounted 4in an upper mulling plate support 81 attached l 12 positioned on the upper end of said shaft.

11, thereby locking the mulling plates imposition. By applying weight @s to the weight support t8 attached to the lower end of the supporting arm Si, a pressure of any given magnitude may be applied to the grinding surfaces of the mulling plates.

Rotation of the lower mulling plate may be accomplished by any known means such, for example, as by sprocket 81 attached toA shaft 62 which is connected to sprocket 81a mounted on -the vertical shaft of a reduction gear 88 by sprocket chain 90. The reduction gear unit may be driven by any suitable means such, for example, by motor 99. Reciprocating motion to the upper mulling plate can be produced eitherfrom the same source of power or by a separate driving mechanism. In the embodiment of the in 92, 92, cast integrally withv the base 6l), has suitahlv mounted on its upper end a Wheel 94 with crank pin 95 rigidly attached thereto at its periphery. Connecting rod 98 is vertically adjustable about'the pin 91 whch is fitted onto member 98 fastened to the reciprocating housing 'li in any convenient manner. The opposite end of the connecting rod is provided with an opening which nts over the crank pin 95. Reciprocating motion of the upper mulling plate may be provided by sprocket wheel W0 attached to shaft 9i which is connected to sprocket lill mounted at the end of a vertical shaft of a gear reduction unit 88 by sprocket chain- |02.

Figs. s, 7, and s show stm another modification I coming within the present invention, wherein the upper plate, instead of reciprocating in a straight line motion over the lower mulling plate, oscillates through an arc of a circle.

The base I0, the vertically adjustable member III, and the oscillating member I|2, constitute the main framework of the machine. A lower mulling plate II 3 is removably mounted in a lower mulling plate support |I4 disposed at the upper end of a vertical shaft II5 of a gear reduction unit I I6v mounted conveniently on a gear reduction support I|1 of the base I|0.

An upper mulling plate I|8 positioned in an upper mulling plate support secured to a universal joint I2| mounted at the lowep,` end of a rotating and oscillating shaft |22 journaled in a bearing |23 is provided, the bearing element |23 being fitted into the lower arm |24, towhich the vertically adjustable member II| is secured by means of supports and pin I3I. Vertical movement of Athe shaft |22 within the bearing |23 relative to the lower arm 24, may be prevented by any convenient means such, for example, bynut |26. The universal joint |2| provides a means for maintaining the surfaces of the mulling plates in perfect alignment.

Vertical adjustment of the upper mulling plate is provided in the embodiment of the invention herein shown. The shaft |22 is attached to the lower arm |24 which carries the vertically adjustable member III land is secured for vertically rotatable movement to theioscillating member H2 at one end by pin |21 which is journaled in bearings |28, |28 of the oscillating member II2. The lower arm |24 is likewise provided with supports |30, |30 in which is journaled pin |3I, the' latter securing the member III to the arm |24. Mounted on the opposite end of the member I|I is handle |32 by means of which member I|I is rotated vertically about pin I3I, and llikewise vertically rotatable about pin |33 which is journaled in bearings |34, |34 of an upper arm |35 of the vertically adjustable mem ber III. The opposite end of the upper arm |35 is pivotally connected to pin |36 which is journaled in bearings |31, |31 at the upper end of the oscillating member ||2.

This construction provides the necessary vertical adjustment to the surfaces of the mulling plates. A vertical'force applied to the handle I 32 causes the opposite end of the handle to take up a lower position, swinging about pin |36, as shown by the dotted lines in Fig. 7. Simultaneously, as the handle is raised, the lower arm |24 likewise raises, beingfrotated about pin |21. The raising of the lower arm positions the mulling surface of the upper plate out of contact with the mulling surface of the lower plate. When the upper mulling plate is in its extreme vertical position, as shown by the dotted lines, it has passed through an arc of substantially 90, and in this position may, if desired, be locked in place by any convenient means. When the upper mulling plate is in this position, the bottom edge of the oscillating member II2 rests on the top edge of the rbase ||0.

i The oscillating member II2 is disposed at the upper end of a rotatable shaft |39 which is journaled in bearing|38 cast into the base |I0. The shaft |33 not only rotates but is free to move vertically in the bearing. Attached to the lower end of the shaft, substantially in the center thereof, by any convenient means is pin I4|, and mounted on the pin through opening I42a is adjustable weight beam |42 which is supported about ful*` crum point |43 in the base I I0. suitably disposed on one end of the weight beam is a slidable and adjustable weight |49 adapted to be freely moved horizontally along the beam.

Cil

Disposed at the lower end of the shaft |33 is a roller bearing |44 which is rigidly held in place by nut |45. The lower race of the bearing is tightly fitted to the shaft and rotates therewith. while the upper race is free from the shaft and remains substantially stationary. When the mulling surfaces are in contact with each other. the shaft |33 is in its raised position, andthe upper surface of the upper race of the ball bearing rests on the lower surface of the weight beam. The weight |49 is transmitted to the surface of the mulling plate through the bearing on the upper race of the ball bearing and the fulcrum poin Oscillating motion of the oscillating arm 2 is provided through an oscillating finger |40 rigidly attached to the shaft |39 which is actuated by a crank pin |41 positioned at the periphery of a gear |48 attached to shaft |50 journaled in bearing I5| cast in the base H0. The gear |40 meshes with the teeth of gear |52 which is mounted on shaft 5.

It will be obvious to those skilled in the art that other modifications may be employed, and the present invention is n'ot limited to the specific embodiments herein shown. Y

The design of the mulling plates for use in grinding the pigments or inks in oil or other vehicles may be altered. While circular plates have been employed, any conveniently shaped plates may be used. While glass is preferred, it is not essential that this material be used for the successful operation of this invention. `v ith regard to the mulling surfaces, it is absolutely necessary that theSr be uniformly smooth and even, otherwise small particles will become lodged on the rough or uneven surfaces of the mulling plates and produce particles of non-uniform size. The mulling plates, preferably, should be readily` adjustable on the mulling plate supports. Under some conditions of operation, it might be advantageous to employ different mulling plates for each grinding operation, so that, during the mulling of the next sample, the operator can remove the pigment and make the necessary tests on the sample previously ground. r

The speed of rotation of the lower mulling plate and the reciprocating and rotary motion of the upper plate has-not been found to be critical, and it is not intended to place any limitation thereon. In one machine, constructed according to the embodiment of the invention shown in Figs. 1 and 2, the lower plate rotates at a speed of R. P. M. while the upper mulling plate reciprocates over the grinding surface of the lower vmulling plate through a 2" stroke (one inch on each side of the center line) and with a frequency of one complete oscillation for approximately every 11/2 revolutions of the larger plate. The average speed of rotation of the upper mulling plate is dependent primarily on the length of the reciprocating stroke. The instant the upper and lower mulling plates are exactly centered, these plates will rotate at approximately the same speed. As the upper mulling plate travels from its central position, either to the right or left, its rotary speed decreases and reaches a minimum at the end of the stroke. The actual relative variation in speed between the mulling plates is, therefore, not a constant, but varies between the maximum speed, which occurs when the plates are centered, and a minimum speed which is the speed obtained at the end of the stroke. Other factors such as the pressure between the plates and the viscosity of the materials asians to be ground aifect the rotating speed of the upper plate, but these factors are of relatively minor importance. Under the above-mentioned operating conditions, the upper muliing plate rotates at an average speed of approximately 100 R.. P. M.

Various means for applying the pressure to the plates have been shown in the embodiments herein disclosed. Other means will be readily apparent to those skilled in the art.

It will likewise be apparent to those skilled in the art that certain factors will have a bearing on the final product. These factors comprise the travel of the reciprocatory plate, the time of .mulling, the pressure on the muliing plates, the pigment 'or vehicle being tested, etc. The specific conditions for an optimum treatment will have to be determined on the basis of a few relatively simple trials, but this will be merely a routine matter to one skilled in the art of color testing.

It has been discovered, according to the present invention, that the pigments or inks being mulied are under no conditions of operation permanently removed from the field of grinding. In those muliing devices hereinbefore referred to where the upper muliing plate was off center with respect to the lower muliing plate, there is a. serious tendency for the particles to become permanently removed from the eld of grinding by their being picked up on the edges or the off-center plate. This disadvantage is entirely eliminated by the present invention, and pigments and inks once vplaced in the eld of grinding remain permanently therein during the entire muliing operation. This outstanding advantage results from the particular motion imparted to the muliing Plates and the relative speeds thereof. In the operation of the mulling plates herein disclosed, there is a pronounced tendency to pull the ink or pigment away from the edges of the upper mulling plate as fast as it gathrs. With other types of muliing machines not constructed according to this principle. the tendency to pull the particles away from the edges of the plate is not so great and, consequently, the particles are picked up on the edges of the plate and-permanently removed from the field of grinding. While beveling the edges of the upper muliing plate reduces somewhat the tendency .to pick up the materials on the edges of the plate, this modification alone does not effectively eliminate this objectionable feature. Prior art devices having off-center mulling plates with beveled edges still exhibit this tendency to permanently remove the materials from the eld of grinding. Correspondingly, the pick up of materials on the upper muliing plate of muliing machines constructed according to the present invention is relatively slight even with a muliing plate having sharp edges.

In the embodiments of the invention herein disclosed, all of the adjustments have been made in the upper muliing plate. While this is usually convenient,it is not an essential limitation, and the adjustments may be obtained in the lower plate either through vertical or horizontal movement. It is likewise not essential that the plate be horizontal, as vertical or inclined plates may b e used. j

Various arrangements of equipment have been shown for'driving the muliing plates. Others will be readily apparent to those .skilled in the art. The mechanism maybe either electrically or hand driven. Furthermore, the use of automatic devices for stopping the machine after a designated predetermined number of movements has taken place may be readily adapted tothe .In A.

machine, said automatic stop either operating on the rotary motion of the lower or upper muliing plates or on the reciprocating motion of the upper plate. Devices of this kind are commercially available and can be conveniently added' uses, all of which will be readily apparent to those skilled in the art such, for example, as in the preparation of drugs and like n. aterials which must necessarily be ground or mixed in small quantities. f

The present invention provides an improved apparatus for grinding pigments and inks into oils, which was not known to the prior art. Due to the combination rotary and reciprocating motion, a product of uniformly fine particle size is obtained and canvbe readily duplicated. It is not necessary to employ skilled workmen to carry out the muliing operation. A grinding and mixing action as well as the permanent vretention of the particles in the eld of grinding is provided by the present invention, the combination of which, to my knowledge, has never before been obtained in prior art rub-out machines. The grinding and mixing action effectively eliminates the dead spot and gives `a relatively uniformly ground product.

A constant pressure is at all times'assured for any given set of conditions.

requirements of operation. A further advantage of the device herein disclosed is that the ink or pigment need not be picked up and redistributed over the plates and subjected to further grinding action, but fine particles can be obtained in one grinding cycle. In fact, the preliminary superficial mixing with the oil and pigments is necessary only to prevent the partially wetted powder from caking and sticking to one or both of the muliing plates.

As many apparently widely diierent embodiments of this invention may be made without departing from the spirit and scope thereof; lit is to be understood that the invention is not limited to the specic embodiments thereof except as defined in the appended claims.

I claim:

1. A grinding apparatus for muliing materials into oil or other vehicles, comprising two rotatable grinding plates having co-operating smooth grinding surfaces between which the materials may be placed for grinding and adapted to be moved into and out of contact with each other, means for positively rotating one of said plates,

., means for reciprocatingl the smooth surface of the other plate over the smooth surface 'of the positively rotating plate, means for maintaining said other plate in operatively-disposed relationship continuously over the substantial center of .said positively rotating plate, and means for Adjustments may be readily made to the machine to meet other of contact with each other, means for rotating one of said plates, means for reciprocating the smooth surface of the other plate over the smooth surface of the rotating plate, means for maintaining said other plate in operatively-disposed relationship continuously over into oil or other vehicles comprising two -flat rotatable grinding plates havingY co-operating smooth grinding 'surfaces between which the materials may be placed for grinding and adapted to be moved into and out of contact with each other, means for positively rotating one of said plates, means for reciprocating thesmooth surface of the other plate over the smooth surface of the said positively rotating plate, means for maintaining said other plate in operatively-disposed relationship continuously over the substantial center oi.' said positively rotating plate, and means for maintaining said smooth grinding surfaces in continuous contact with each other under a predetermined constant pressure during the rotation of said positively-rotating plate.

4. A grinding apparatus for mulling materials into oil and other vehicles, comprising two rotatable at grinding plates of unequal size having co-operating smooth grinding surfaces between which the materials may be placed for grinding and adapted to be moved into and out of contact with each other, means for positively rotating the larger of said plates, means for reciprocating the smooth surface of the smaller of said plates over the smooth surface of the said larger rotating plate, means for maintaining said other plate in operatively-disposed relationship continuously over the substantial center of said positively rotating plate, and means for maintaining said smooth grinding surfaces in continuous contact with each other under a predetermined constant pressure during the rotation of said positively-rotating plate.

5. A grinding apparatus for mulling materials into oil or other vehicles, comprising two rotatable fiat grinding plates of unequal size having co-operating smooth grinding surfaces between which the materials may be placed for grinding land adapted to be moved into and out of contact with each other, means for rotating the larger of said plates, means for reciprocating the smooth surfaceof the smaller of said plates over the smooth surface of the said larger plate, means for maintaining said smaller plate in operativelydisposed relationship continuously over the substantial center ofsaid larger plate, and means for maintaining said smooth grinding surfaces in continuous contact with each other under a predetermined constant pressure during the rotation of said positively-rotating plate.

6. A grinding apparatus for mulling materials into oil or other vehicles, comprising two horizontally positioned flat rotatable grinding plates of unequal size and circular in cross-section having co-operating smooth grinding surfaces be-.

tween which the materials may be placed for grindingand adapted to bemoved into and out of contact with each other, the smaller of said plates having beveled edges, means for rotating the larger of said plates, means for reciprocating the smooth surface of the smaller of 'said plates over the smooth surface of the larger plate,

means for maintaining said smaller plate in operatively-disposed relationship continuously over the substantial center of said larger plate, and means for maintaining said smooth grinding surface into continuous contact with each other under a predetermined constant pressure during the rotation of said larger plate.

7. A grinding apparatus of the class described, comprising a horizontally disposed lower mulling plate circular in cross-section, the upper surface of which has been ground smooth, mounted at the end of a rotatable shaft, means for imparting rotary motion to said shaft, a smaller upper flat plate of circular cross-section with beveled edges, the lower surface of which has been ground smooth, disposed at the end of a reciprocating shaft, and adapted to be moved into and out of contact with the smooth surface of the said larger plate, said smaller plate, when in' contact with the mulling surface of the larger plate, being free to simultaneously rotate and reciprocate thereover, means for `imparting reciprocating motion to said smaller plate, means I for maintaining said smaller plate in operativelydisposed relationship continuously over a central point of said lower plate, and means for maintaining said smooth grinding surface of said plates in continuous' contact with each other under a predetermined constant pressure during the rotation of said larger plate.

8. A grinding apparatus of the class described, comprising a horizontally disposed lower mulling plate circular in cross-section, the upper surface of which has been ground smooth, mounted at the end of a rotatable shaft, means for imparting rotary motion to said shaft, a smaller upper at plate of circular cross-section with beveled edges, the lower surface of which has been ground smooth,'disposed at the end of a rotatable and reciprocating shaft, and adapted to be moved into and out of direct 'contact with the smooth surface of the said larger plate, said smaller plate, when in contact with the mulling surface of the larger plate, being free to simultaneously rotate and reciprocate thereover, means for imparting reciprocating motion to said smaller plate, means for maintaining said smaller plate in operatively-disposed relationship continuously over a point central of said lower plate, and means for maintaining said smooth grinding surface of said plates in continuous contact with each other under a. predetermined constantl pressure ,during the rotation of said larger plate. 9. A mulling device for incorporating materials into oils and other vehicles comprising, in combination, oppositely-disposed mulling plates in substantially concentric relationship with each other and each provided with cooperating smooth grinding surfaces between which the material to be ground or mulled lis placed, means for moving the grinding surfaces of said plates into and out of direct contact with each other, means for positively rotating one of said plates, means for applying a reciprocating motion to an oppositelydisposed rotatable plate over the smooth surface of said positively rotating plate, means for maintaing said latter plate in operatively-disposed relationship continuously over the substantial center of said positively rotating plate, and means for maintaining, throughout rotation of said positively rotating plate, the smooth mulling surfaces of said oppositely-dispos'ed plates in substantially continuous contact with eachother under a predetermined, constant pressure.

EDWARD F. KLENIQI, Ja.