US2269197A - Grinding and polishing apparatus - Google Patents

Description

Jan. 6, 1942. A. E. HAMILTON GRINDING AND POLISHING APPARATUS 7- sheets-sheet 1 Filed Sept. 20, 1959 Jan. 6, 1942. A. E. HAMILTON GRINDING AND POLISHING 4APPARATUS l 7 Sheets-Sheet 2 'Filed sept'. 2o, 19:59

Jan. 6, 1942. A. E. HAMILTON GRINDING ND POLISHING APPARATUS FiledvSept. 20, 1939 7 SheeiZS-Sheel .3

Jan- 6, 1942- A. E. HAMILTON 2,269,197

I GRNDING' AND FOLISHING APPARATUS l Filed sept. 20, 1959 vishets-sheetg Eig. 4

ATTORNEY.

Jan. s, 1942.

A A. Ej HAMILTON 'GRINDING- AND POLISHING APPARATUS Filed sept. 20, 1939 '7 sheets-sheet 5 j INVENOR.; j @Mmmm/Lm;

ATTORNEY.

Jan. 6, 1942. A. E. HAMILTON 2,259,197

l GRINDING AND POLISHING 'APPARATUS Filed sept; v2o, 1959 7 sheets-sheet e A BY.

ATTORNEY.

` Jan 6, 1942. A. E. HAMILTON y 2,269,197

V GRINDING AND POLISHING APPARATUS 'Y Filed sept. 2o, 1939 'I sheets-sheet v ATTORNEY.

UNITED STATES PATENT oFFlcE 12 Claims.

My invention relates to grinding and polishing apparatus and is especially suitable in the grind- 69,197 GmNnING AND PoLIsnING ArrARATUs Alfred E. Hamilton, Pittsburgh, Pa. Application september zo, 1939, serial No. 295,765

ing and polishing of strip material and sheets of material, including steel strip produced on continuous mills, and large metal sheets.'

In the grinding and polishing of sheet and strip material by moving the work past' abrasive and polishing rolls or blocks, trouble is experienced through the forming-of streaky areas longitudinally Aof the surface being operated upon, because all portions of the abrading roll or block do not produce the same degree of grinding or polishing action. l

My invention has for one of its objects the provision of a method and means whereby the material is ground and polished by surfacing toolswhich are moved upon the -strips or sheets in such mannerthat greater' uniformity vof surfacing is effected than is possible with various types of apparatus heretofore employed.

An important feature of my invention resides in the provision of means whereby during traveling movement of the work past'the surfacing tool or tools, the said tools are oscillated in a direction transversely of the path of travel, to thereby avoid the forming of elongated streaks on the work.

The apparatus can be employed both to preliminarily grind the work and thereafter to impart a high polish thereto, it being understood that the work can be first passed through one or more of my grinding units and then passed through other of m`y units where polishing and buing operations are performed thereon. The grades of abrasive employed in the grinding units may be graduated from coarse to fine flour grades,

while a higher polish will be imparted to the work by buing rolls or the like lcontained in otherA tion` looking in the direction vof the arrows II-II of Fig. 1; Fig. 2a is a sectional plan view on an enlarged scale of a` portion of the operating mechanism of Fig. 2; Fig. 3 is a side elevational view of a modified form of machinewhich con- 35 arm 45 that projects rearwardly from one of the tains two pairs of polishing rolls; Fig. 4 is an end view thereof; Fig.5 isa plan view; Fig. 6 is a sectional plan view, taken on the line VI-VI of Fig. 7 and showing still another modified form of polishing elements; Fig. '7 is an end view thereof Fig. 7a is a cross-sectional view of one of the blocks of Fig. 7, and Figs. 8 and 9 are side and plan views showing a modification of the reciprocating device of Figs. 2 and 2a.

The apparatus in one of its simplest forms is disclosed in Figs. 1 and 2, and comprises'a base I0, carrying uprightend framemembers and |2. The end members and I2 are vertically slotted to receive a slide member I3. A cross member or bar I4 is carried by the members and I2 and serves as a raceway for anti-friction rollers l5, upon which the slide member I3 is supported. The members and I2 support bearing blocks I6 that serve. as raceways for antifriction balls I1, raceways I8 also being providedI on the slide I3 for the ball bearings l1. Adjusting screws I9 are provided for adjusting the race members I6 to compensate for wear in the ball bearings.

A base plate 2| is detachably mounted upon the slide member I3 and is held in place thereon by its tongue or rib 22 that fits within a. groove in the upper face of the slide-member and by screws 23. Removal of the screws 23 permits'` 21 and 28, that in turn support brackets 29 and 30 respectively. 'I'hese brackets 29 and 30 support surfacing rolls 3| and 32 respectively, in a manner similar to that yin'which the surfacing rolls of Figs. 5, 6 and 7 are supported on their respective brackets. ,Y

The brackets 29 and 3U have rearward extensions 34'and 35 respectivelythat serve as supports for electric vmotors 3 6 and 31, which through belts 33 and 33 drive the surfacing rolls 3| and 32 respectively. The bases of the motors are pivotally connected to their brackets as at 40,' and adjusting 'screws vIl are provid'l whereby the tension ofthe driving belts 33-33 can readily be adjusted.

The bracket members. 23 and 30, through links 42 and I3, are connected to a counter-balancing lever 4I that is pivotally mounted upon a bracket together with the motors and polishing wheels carried thereby are oscillatable on their respective shafts 21 and` 28, and the members 42, 43 and 44 serve as counter-balancing elements whereby tendency of the bracket 29 to tilt on its shaft 21 through unbalanced weight is counteracted'or counter-balanced by the weight of the bracket 30 and the parts carriedythereby. Thus, if the distribution of weight on the bracket 29 is such vas to tend to rock it in a counter-clockwise direction, and the distribution of weight on the bracket 30 is such that its center of gravity tends to rock it in a counter-clockwise direction, as

would -be the case if the weight of the motors 36-31 exceeds the weight of the polishing wheels. the link arrangement above described'would produce a counter-balancing effect to thereby maintain the polishing rollers 3|32 in proper operative position with respect to a sheet or strip being operated upon. The counter-balancing of the surfacing rolls .insures that they will bear with equal pressure against the upper and lower surfaces of the work. The rolls 3l and 32 can be held against the work by a. suitable spring, or by the solenoid and one of the levers and links of Fig. 3.

The surfacing rolls 3| and 32 may have their working faces provided with any desired abrasive or polishing material. 4For example, they may be faced with emery or sand, or may be faced with bufling material. One form of roller which may suitably be employed is disclosed in my Patent No. 2,113,836, which shows a pneumatic roller containing a sleeve that is faced with abrasive y material.

The slide I3 and the base plate 2| are reciprocable as a unit transversely of the work being vfed through the machine, by means to be hereinafter described, the surfacing rolls being simultaneously driven by their motors, so that the rolls will be shifted in axial directions while they are operating upon the steel or other material.

The said transverse reciprocatory movements of the slide I3 which carries the surfacing rolls, together with vibratory movements thereof. are effected by mechanism that is shown more clear- -ly in Figs. 2 and 2a, and comprises a motor 49 that may be of the variable speed type and which, through a belt or chain drive 30, drives a shaft on which a gear wheel 5I is mounted. The gear wheel 5| meshes with a gear wheel 52 contained within a gear casing 53 that is secured to the base frame of the machine. The gear wheel 32 is secured to a shaft 54 which is enlarged at 35 toform a cage for a' gear wheel 56 and its shaftl.l The shaft 61 is Joux-nailed in the barrel -55 eccentrically of the shaft 54, so that it formsin eil'ect a crank pin. A bearing sleeve 5I is rigidly mounted within the casing 33 and carries a bearing ring 59 for supporting the cage or barrel 55 that'is formed integrally with the -s ring so having gear teeth is rigidly secured pivotal connection at with the slide member A upright members 26. 'I'he brackets 29 and 30 It will be seen that during rotation of the shaft 54. the shaft 51 will ,function as a crank pin to impart reciprocating movements to the slide I3 and that simultaneously there will be shorter vibratory movements imparted thereto by reason of thel rotation of the gear wheel i6 in the gear ring 60, such rotary movements being imparted to the crank 6I. This combination of short vibratory movements with the longer reciprocating movements, in directions transverse to 'the path of travel of the work through the machine, results in a better and more uniform polishing of the metal than would be possible with simple reciprocatory movements, thereby avoiding streakiness in grinding and polishing, or contrasting zones of light and heavy surfacing.

The machine is shown as operating upon strip steel 65 that is being drawn from an un-coiler 66, over guide rollers 61 and 68 by a coiler 69. The coilers and un-coilers may be of any suitable form well known in the art.

In order to prevent bending or lateral shifting of the strip through the transverse reciprocatory movements of thel rolls thereon,I provide guide rollers 1I of spool-like form for engaging the edges of the strip. These Vrollers have their shafts extending vertically through slots formed in an angle bar 12 (Figs. l, 2 and), and the rollers are thereby adjustable on said bar'to strips of various widths. The barY 12 is .inf turn adjustable upon the framework `of themachine and .to this end is provided with slots A*13 'through which attaching bolts or screwsv 14Hextend to clamp it in adjusted positions. .By having the bar '12 adjustable on the framework of the machine. the rollers when set for a1 sheet of given width can be adjusted as a unit vtoward either end of therolls by shifting the, bar 12, so that substantially the entire working surfaces of thel rolls can be utilized. For example, a strip of narrow width can be subjected'to the surfacing action of the rolls at a zone lnearone end of the .rolls, and when said zone becomes somewhat worn, the bar 12-can be fshiftedrto move the guide spools 1l toward the other-end of the rolls. The motors 36 and 31 can'be ofi-'the reversible type and the surfacing rollers`3|` and 32 can be driven either in the direction oftr'avel of the strip, or opposite to said travel, as may be desired. If the rolls are drivenin thesame direction that the strip is moving, and with the peripheral speed of the rolls greater' than the rate at which thestrip is traveling,lthere will be polishing action on the strip, butto alesser degree than if the surfacing rollers are driven in a direction opposite to the strip travel.

In order that the machine may be employed to polish sheets as distinguished from long strip steel, I provide feed rollers 16 and' 11 at each end of the machine, which 'rollers may suitably be rubber-faced in order to reduce danger of slippingA on the sheets, and which -may desirably be pneumatic, of the general form shown in my Patent No. 2,113,836. The rollers are journalled in brackets 18 that are carried bythe base frame of the machine, and the shaft bearings for the rollers are adjustable by .means of screws 13 which will take up wear and will :also vary the roll pressure. The shafts ofthe rollers 16 carry gear wheels 30 that mesh with gear wheels Il on the shafts B2 of the rollers 11. Each shaft 82 has bevel gearconnection at 33 with a vertical shaft 34 that. through a clutch connection at 35, is driven by a roller shaft section 3B. which carries a worm gear 81. The 4clutches 33 will be provided with suitable actuating mechanisms, so that they can be disengaged when strip steel is to be-polished instead of sheets. Worm wheels 81 are driven by worms 88 that are'mounted on a shaft 89 which is driven from a variable-speed motor 90. The motor 90 may-suitably be of the reversible type, so that a given sheet can be passed back and forth through the machine.

In grinding or polishing thin sheets, the surfacing rolls 3| and 32 will ordinarily be drivenv so that at. their points of contact therewith, their peripheries will move in the same direction as the sheet, but at a faster rate. The rollers 16--11` will in that case serve to retard the'tendency o f the sheet to be drawn forward rapidly under the frictional drag of the surfacing rolls. Ordinarily a strip or sheet will be subjected to successive operations by grinding and polishing rolls and a series of units of the type shown in Figs. 1 and 2 may be mounted in tandem or sequence, the rough polishing or grinding being effected on some of the machines and finishing operations performed on succeeding machines. l

In Figs. 3, 4 and 5 I show a single machine or unit wherein two pairs of surfacing rolls are employed. In this arrangement the two pairs of rolls are mounted upon a base plate 92 which corresponds to the base plate 2| of Figs. 1 and 2, and which maybe mounted upon a slide corresponding to the slide I3 and which also -may be reciprocated in the same manner as the lslide I3 of Figs. 1 and 2. Upstanding frame members 93 are provided at the ends of the base plate 92, and these two uprights serve to support the two sets of polishing mechanism which are identical in form and hence detailed description of only one set is required.

A` pair of shafts 94 and 95 are journalled in the uprights 93. The shaft, 94 extends through Lthe backWardly-extending ends 9'| and 9|! of a bracket 99. and the bracket is non-rotatably connected to the shaft 94 by a set screw |00. A second bracket member v-I is pivotally connected at as the bracket 99 is supported on its shaft 94.

A motor |24 is mounted on the shaft ||1, and

` positioned in an extension |25 of the bracket its midportion to the midportion of the bracket 99, by a screw or bolt |02 that has threaded connection with the bracket 99. The bracket |0| has outwardly-projecting bearing bosses |03 and |04 for supporting a shaft |05 that carries a surfacing roll |06 and is driven by an electric motor |01, which is carried by an extension |08 of the bracket 0|. It will be'seen that the surfacing roll lxtogether with the brackets |0| and 99 can be oscillated as a unit with the shaft 94.

The bracket |0I. and hence the roll |06. is angularly adiustable in a vertical plane by means of screws I|0 and that have threaded connectionwith an extension |I2 of the bracket 99. and whose inner ends have abutting engagement with'a rearward `extension or boss |I4 that is carried by tbe bracket IOI. A screw or bolt |I5 carried hv the' extension |08 of the bracket `I0| extends through aI vertical slot in the bracket member I l! and has a nut which is tightened to hold the bracket. I III rmly in placentvarious positions of adjustment on the pivot bolt |02.

This nut will be loosened while making adjustl ments with the screws IIO .and III. Turning of the screws I|0 and III will effect .rotatable adjusting movement of the bracket 0| on the pivot bolt I 02 to tiltthe axis of the roller slightly in a vertical plane, so that it will bear evenly upon a strip or sheet that passesl between the surfacing rolls.

'I'he lowerroll IIB is v-mounted on ashaft ||1 which is journalled in bearings I I8 and ||9 that |20. The bracket |20 has a boss |26 projecting between upper and lower extensions |21 and |28 of the bracket |22. The bracket extension |25 carries a bolt |29` that extends through a vertical slot in the bracket extension |21, so that the bolt-and-its nut can be utilized to securely clamp the bracket |20 in its various positions of pivotal adjustment on the bolt I2I.

Adjusting screws |30 and I3| have threaded engagement with the extensions |21 and |28 respectively, and abut against the boss |26 of the .bracket |20, so that the bracket |20 which carries the roll |I6 can readily be adjusted to various tilted positions on its pivotal support |2I, and it will be securelyy clampe'd in such positions by.

the bolt |29. y

A stud or stud shaft |33 iscarried by one of the stationary uprights 93 of the framework and pivotally supports a lever I 34 that at its upper and lower ends is pivotally connected with links |35 and |36 respectively. The link |35 is connected at its other end with the bracket 99 which, through the bracket |0I, supports the roll |06. The link |36.at its outer end has pivotal connection with the bracket |22 which, through the bracket |20, carries the roll ||6. Itwll be seen that -by this arrangement, the rollers and the brackets which support the same will counterbalance one another. Thus, while the roll |06 and its associated parts tend to rock in a clockwise direction with their shaft 94, such force is transmitted through'the link I 35 to the lever |34 and exerts a turning force on said lever, in a clockwise direction, with the result that the lower end of the lever |34 exerts a pull on the link |36 which tends to move the roll II6 and its associated parts in a counter-clockwise direction.

The surfacing rolls |06 and IIB may be of any suitable material as mentioned in connection with the surfacing rolls 3| and 32 of Fig. 1. each roll being driven by its own motor in the desired direction and theedges of the strip being guided by the adjustable rollers 1|, as explained in connection with the description of Figs. 1 .and 2. Also. the strip may be fed through a desired number of sets of surfacing rolls or sheets fed therethrough. .For the feeding of sheets, I will provide power driven pinch rolls corresponding to the rolls 16 and 11 of Fig. 1. v

In this instance.- as in the case of the form of apparatus shown in Figs.y 1 and 2, the base member 92 which will be mounted lon a slide corresponding to the slide I3 of Figs. 1 and 2, can readilv be removed to permit of convenient substit-ution of polishing units as Where the surfacing rolls on the unit being used have become worn and need replacement, or where a change in the material being operated upon requires the use of surfacing rolls of .another character.

In order to prevent damage in case the stripadvancing or feeding means should accidentally stop while the surfacing rolls are in operation, I provide means for quickly or automatically releasing the pressure of .the surfacing rolls upon the strip. It will be understood that if a strip or sheet should come to rest while the surfacing rolls are operating, frictional heat'and abrasive .source of power through conductors |41.

'shown in Fig. 3, the solenoid is. in an energizedv weer would be developed to such an extent as to damage the sheet and perhaps also the surfacing rolls.

To this end I secure an arm |38 to each of the brackets A link |39'is pivotally connected at its upper end to the arm |38 Aand at its lower end to a lever |40. Each lever |40 is pivotally connected at |4| to oneof the uprights. A solenoid |42 is mounted forvertical adjustment upon the frame member 93.'. An adjusting screw |43 has threaded Yconnection with a boss |44 on said side frame'and will be turned to adjust the solenoid tovarious heights. noid'has a movable core which is provided with an upwardly-projecting extension |45 for engagement with the innerends of the levers |40.

The solemembers |64 and |65 will correspond to the memyber 55 of Fig. 2a and the other parts provided as in Fig. 2, so as to give combined reciprocatory and oscillatory movements to the surfacing blocks |55 and |56. The members |64 and |65 operate links |66 and |61 respectively, that are plvotally connected to the ends of the bars |54 and |56.

' The links |66 and |61 correspond to the link 63 of When the solenoid isenergized, its core is moved upwardly and consequently the inner ends of the levers |40 are moved upwardly. This movement of the levers on their pivotsv |4| exerts a downpull on the links |39, thus rocking the brackets |0| downwardly and simultaneously, through the counter-balancing links, moving the brackets upwardly, thereby movingthe surfacing rolls together to engage the upper and lower faces of the work strip. The links' |39 are composed of screw threaded sections Awhich can be adjusted to vary their lengths. Also the adjustment of the solenoid |42 will vary the spacing between the upper and lower surfacing rolls and the pres-- sure thereof upon the work'. f

The solenoid |42 is energized from a suitable As raise`the links |39 and thuseffect separatingv movement of the surfacing rolls; and prevent continued operation thereof upon the strip. The

Fig. 2. The crank devices |64 and |65 are circumferentially oiset relatively to one another on their shaft, so that when the upper block is being moved in one direction across the work, the other block will be moving in the opposite direction.

v A series of steps in the treatment of strip steel and th'e like can conveniently comprise the passing of a rolled strip through one or more grinding units, as herein described, to grind the surfaces of the strip to a desired smoothness; pickling the strip; running the strip through cleaning tanks to remove loose grit preparatory to polishing, and then passing the strip through polishing rolls operated as herein described. This procedure is desirable where a mirror finish is wanted, as in the case of stainless steel. Somewhat the same procedure can be followed in preparing a strip for plating. In the latter case, it usually will not be necessary to buff or give a mirror nish to the strip, because the final grinding operation thereon will ordinarily leave the strip suiiiciently smooth for iplating -purposes. In many instances wet grinding and polishing will be employed, with the use of water or oil.

In order to prevent or overcome any tendency for polished wave lines to be formed on the work through the reciprocating and vibratory movements heretofore described, such as might occur through a pair of surfacing elements springs are interposed betweenbosses |5| on y the lside frame 93 and 'pads |52 that are on the under sides of the levers |40. A'llhe circuit of the conductors |41 can be manually-.controlled by an operator who will immediately break the circuit if the strip comes to astop in the machine, but I preferably will have lthe circuit of the solenoid in series with the circuitof a motor which drives the strip or sheet that is being polished. For example, it could be in circuit with the motor 90 of Fig. i, in which case iffithemotor circuit is broken, the circuit through thesolenoid |46 will in cross section'as. shown in Fig. 'la and which are,

faced with abrasive` material. :For example, sheets |5641 of sand paperorsheets of emery cloth, or felt, may be applied to the work-engaging surfaces of these blocks'. `The biock' |55 has 1 of whose shaft crank .elements 1|64-,and |65 are mounted. These crankelements `may suitably be of the form shown in Figs. zand 2a, in that the tracking or following the same path as those followed by precedingl surfacing elements, I so arrange the reciprocating devices that certain of the pairs of surfacing elements will be given a different length of vibratory stroke than other elements.

To this end I provide means such as shown in Figs. 8 and 9 for adjusting the throw of the links which reciprocate the slides I3. In this arrangement the crank pin 62 of Fig. 2a has connection with a link |10 that at its upper end has pivotal connection with a slide block |1| that is carried by one arm |12 of a bell crank leverV |13. The bell crank is pivotally mounted upon a boss |14 that is carried by the framework The other arm of the bell crank is pivotally connected to a link |15 that is in turn connected to the slide memberlS. The throw or distance.

of angular movement of the bell crank |13 is adiusted by a hand screw |16 that is journalled .in a boss |.11 ofthe arm |12. The shank of the member |16 has threaded engagement with the slide block- |1|' so as to shift the block along the slot in the arm |12, whereby the position of the block |1| on the bell crank will determine the distance through which the slide member I3 is reciprocated.

I claim as my invention:

l. Surfacing apparatus comprising means for imparting traveling movement to strip material and the like, a surfacing element positioned for engagement with the material and to extend across the width thereof, and means for imparting combined reciprocator'y and vibratory movements4 tov said element, in directions generally transverse to the path of travel of `the material. l

2. Apparatus for surfacing strip material and the like, comprising means for imparting traveling movement to the material, surfacing elements at the opposite faces of the material, means for supporting said elements ragainst the faces of the material, and means for imparting combined reciprocatory and vibratory movements to the said elements, in directions generally transverse to the path of movement of the material.

3. Apparatus for surfacing strip material and the like, comprising means for imparting traveling movement to the material, a rotatablymounted surfacing element disposed in position to engage one face of the material, with its axis extending transversely of the path of movement of the material, means for rotating the said element, and means for imparting reciprocatory and shorter vibratory movements to the said element in directions generally transverse to the path of movement of the material, while it is being rotated.

4. Apparatus for surfacing strip material and the like, comprising means for imparting traveling movement to the material, a supporting member positioned adjacent to the path of movement of the material, a rotatable surfacing element shorter vibratory movements lto said elements in directions transversely of the path of movement of the material, the length of transverse movements of one of the elements being shorter than the distances another element moves.

9. The method of surfacing strip material and the like, which comprises imparting traveling movement to the material past progressively-arranged pairs of-surfacing elements that engage both faces of the material, and simultaneously with the traveling movement imparting combined reciprocatory and shorter vibratory movements carried by said support in position to engage the material, a driving device on said support for rotating the surfacing element, and means for imparting reciprocatory and vibratory movements to the said supporting member in directions transverse to the said path'.

5. The method of surfacing strip material and the like, which comprises imparting traveling movement to the material relative to a surfacing element, while maintaining said element in contact with the material, and during said movementv imparting combined reciprocatory and shorter vibratory movements to the surfacing element, in directions generally transverse to the Vpath of movement of the material, the vibratory to said elements in directions transversely of the path of movement of the material, the length of reciprocatory movement of some of the said pairs of elements being shorter than the movement of other pairs of elements.

10. Apparatus for surfacing strip material and 'the like, comprising means for imparting traveling movement to the material, a supporting member,l a surfacing element carried by said member in position to engage the material, a shaft having a crank-like extension, a second shaft journalled in said extension and provided with a crank arm, a connection between said f crank arm and the said supporting member, so arranged that the supporting member is recipro- .cated transversely of the said path of traveling movement, when the shafts' are rotated, means forrotating the first-named shaft, and means for simultaneously rotating the second-named shaft.

11. Apparatus for surfacing strip material and the like, comprising means for imparting traveling movement to the material, a supporting member, a surfacingr element carried by said member in position to engage the material, a shaft having a crank-like extension, a second shaft journalled movements being of variable amplitude during insaid extension and provided with a crank arm,

a connection between said crank arm and the rsaid supporting member, so arranged that the supporting member is reciprocated transverselyv of the said path of traveling movement, when the shafts are rotated, means for rotating the firstnamed shaft, means for simultaneously rotating the second-named shaft, and means for adjusting the range of lateral movement which is given to thev supporting member by rotating of the said shafts.

l2. Apparatus for surfacing strip material and the like,` comprising means for imparting traveling movement to the material, a supporting member, a surfacing element carried by said member `in position to 'engage the material, a shaft having a crank-like extension, a second shaft journ'alled in said extension andlv provided with a crank arm,

both faces of the material, and simultaneously with the traveling movement imparting reciprocatory and vibratory movements to said surfacing elements in directions transversely of the path of movement of the material.

8. The method of surfacing strip material and the like, which comprises imparting traveling movement to the material past progressively-arranged surfacing elements that engage the material, and simultaneously with the traveling movement imparting combined reciprocatory and first-named shaft, and means for simultaneously a connection between said crank arm and the said supporting member, so arranged1 that the supporting member is reciprocated transversely of the said path of'4 traveling movement, when the shafts are rotated, means for rotating the rotating the second-named shaft, the said cranklike extension being of different radial length than the radial length of the crank arm.

ALFRED E. HAMIILION. l

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