US910315A - Milling-machine. - Google Patents

Description

J. RIDDELL.

Y MILLING MACHINE.

'APPLICATION FILED 23.17.1905.

lI Deltenteadl Jan. 19,1909.

4 BHEETB-SHEBT 1.

lnvenor John Riddell. -A

Witnesses,

"J. RIDDEL'L. MILLING MACHINE..

APPLIOAYTION FILED APE17.1905.

Ll,SIE1'EBT-S--SIIEET 2.

inventor.'

John Hidde! l.

Patented Jan. 19, 1909.

by Zh/QM mh Sm.

J. RIDDELL.

MILLING MACHINE. APPLICATION FILED APB. 17.1905.

PatentedJan. 19, 1909.`

4 SHEETS-SHEET 3.

lnvenfor John 'Ri'ddel l;

` Witnesses.

J. RIDDELL. MILLING MACHINE.

APPLICATION FILEDAPB. 17.1905.

Patented Jan. 19, 1909.

v L SHEETS-SHEET4 4.

Inventor.

John Rddel I.

Witnesses.

NlTED l) JOHN -RIDDELL OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. t'

MILLN (lt-MACHINE No. 910,315. Specication of Letters Patent. Patented Jam. 19,1909. Application filed April l?, 1905. Serial No. 255,830.

To all whom it may concern: column, a radial arm extending therefrom Be it known that l, JOHN linDnLL, a citiand mounted with respect thereto to permit zen of thc United States, residing at Schenecof a relative turning movement, a cutter tady, county of Schenectady, State of New and a carriage therefor mounted at the end York, have invented certain new and useful of the arm, and a suitable pOWer-trans- 50 Improvements in illilling-Machines, oli' which mitting system for operating the cutter. the following is a specification. rlhe bese of the column of the machine 'italy invention relates to metal. working lits in the shaft opening of the bucketi'nachines, and relates more particularly to Wheel, and in order to adapt the machine .lo a machine for finishing the buckets of elastic for inishing wheels of different sizes, inter- 65 fluid turbines, although it is not limited in all changeable columns are employed. respectsv to this use. When the wheel and machine are in opera- Buckets for elastic fluid turbines heretive position, the cutter-carrying arm extofore constructed have been provided tends parallel with the plane of the Wheel with curved walls or surfaces which merge and is adjustable laterally with respect to a.' 7o into flat tangential surfaces that direct radial position, so that the cutter may be adthe passage of motive fluid, and it. is to justed to make aradial cut for any angle relthe finishing ol" these tangential surfaces atively to the plane of the Wheel. rl`he outer that this invention more speci'lically relates. end ot' the arm is formed into a yoke, and the Hitherto it has been found necessary to cutt r carriage is mounted therein in aman- 75 do this by hand. Obviously, this is a slow ner to permit of its being reciprocated for the and expensive operation, requiring a large Working strokes, and also 'for being moved to number of hands for the Work and a considdilerent radial distances so as to adapt the erable outlay for illes. Moreover, hand- 'machine for iinishing the buckets ci' Wheels ol Work is to a greater or less extent inaccurate different radii. To set the cutter for iinishso and ununiform; this being highly objectioning surfaces of any desired angle, the arm is able because it directly ailectsthc economy adjusted on its axis as well as laterally. Afof operation of the turbines. ter once being adjusted to the proper angle, The object of my machine is to supersede it need not be again adjusted during the .inhandwerk, as to a large part of the inishishing oi the surfaces oi the buckets on the 85 ing operation, solas to improve the quality same side of the Wheel. of the Work and to increase production. The workingl stroke oi the cutter is under The machine is adapted more es )ecially the control of an operator. For this purpose for nishing the flat end surfaces of tie iront the carriage in which the tool is mounted, is of the buckets, or those surfaces `which connected with a hand lever arranged so as 9o extend tangentially to and on opposite to be convenient to the operaton-preier'- sides of the central curved portion. The ably at the extremity of the arm. The cutbuckets, as made in a bucket-cutting ter is intended to linish one surface of a machine or by casting, arc more or less bucket at a time, and al ter all ol the surfaces rough, and the flat Asurfaces may not at oiA the buckets on one side of the wheel have times havefthe proper angle so that 'they been finished, the latter is turned over bodily require to be iinished lThe finishing an or reversed with respect to the machine. important operation, as the elllciency of This necessitates setting the cutter at a corthe turbine depends to considerable responding angle on the opposite side of a degree upon the smoothness the surfaces perpendicular to the plane of the Wheel, as 10o and the uniformity of their angle relatively the angle ol the bucket is reversed. To beto the direction of the jets of the working gin the cutting operation, the carriage is lfluid from the nozzles. moved by the operator so that the cutter will In carrying out the invention, the milling' occupy an initial positon at the outer or 5e machine andi the buckctwrheel or' other tenen end ol' the bucket,'and the cutter is 105 Work to be linisliech may ybe so arranged then adjusted to make the rproper depth of `relatively to each other that either may cut. @ne adjustment suffices 'for all of the be moved progressively to bring the buckets bucket surfaces on one side of the Wheel, and cuttertogether as the finishing opera- ;Vhielr-insures uniformity. The' operator tion proceeds. The 4machine comprises ra' ythen presses the hand' lever to canse theca'r- 11o li-4.., Fig. 3; Fig. 5 is a similar section taken however, be mounted ony a suitable wor Y'one ol the buckets.

column or stub shaft 2, Fig. 6. This latter riage to move inwardly with the cutter, toward root of the uclret, cutting away the surface to the proper finish. When the cutter reaches the root of. tliekbuclret, the lever is reversed, whereby the cutter is Withdrawn. The Wheel or the machine is 'then turned in order to present the next bucket to the cutter, which is finished in the same manner. The operation is thus continued until the dat surfaces oi' the buckets on one side of the Wheel are finished, Whereu on the Wheel is reversed and the machine a `'usted to iinish the other flat surfaces of the buckets.

For a more detailed understanding of the invention, reference is to be made to the iol.- lowing descri tion, and the sco Ae oi the invention Will e set forth in t e appended claims.

in the accom anying drawings, which illustrate one em odiment of the invention, Figures l and 2 are perspective viewsfobserved 'from different points', of a milling inachine shown in operating osition on a turbine bucket Wheel; Fig; 3 is a ongitudinal section oi' a cutter carriage, and the adjacent portion oi the arm. supporting the same; Fig. l is a transverse section ol the erm taken on line on line 5-5,.l"ig. 3, and showin@ the cutter carriage in elevation g llig. 6 is a ongitudinal section of the supporting column, showing the bearing construction' of 'the machine; Fig. 7 is a plan vier/v of the cutter-carrying arm and the means for adjusting the same laterally on the supporting column; Fig. 8 is .a detail view o' the cutter and Fig. 9 is a ,View illustrating a section of a bucket Wheel with certain of the buckets in nished and untinished condition, and the cutter dressing in the present instance, the buclet Wheel i is shown blocked up on the table or worlo holder in a horizontal and iXed position, with ythe milling machine mounted thereon in such 'a manner as to be revolved on the axis of the Wheel forpresenting the cutter successively to the buckets. The Wheel ma holder or table so as to turn, and it may turn in either a horizontal or vertical plane. In the latter case the milling machine is mount ed in iixed position, and the wheel is mov-- ably supported in proper relationthereto.

The machine is supported in position von a is provided at its base with shoulders 8 und 4 of different diameters, the lower one of which lits the shaft-opening 5 of the bucket Wheel, 'while the upper one, being of larfger diameter, rests upon the up er surface ci the Wheel and supports the oo umn in lined position. The column forms an interchangeable part the ma 1rine, bucket wheels bevi shc different diari.

'andi-7. -the same 1s mounts from one another, only in respect to the diameters of the shoulders 3 and 4, While the diameter of the shaft proper is uniform or standard for a single machine. 0n the column 2 a radial cutter-carrying arm 6 is mounted so as to pivot thereon, Figs. l, 2 in order to ermit the arm to turn, on the column 2 by means of a hollow column '.7, which forms a rigid part of the arm, and Which snugly nts the inner column so as to prevent any apreciable play on the latter and consequent ,vibration during the cutting stroke. The lower end of the hollow column rests upon anti-friction balls 8, Fic. 6, that are held in a race 9 formed yon-the Ashoulder 3. The arm extends from the supporting column in a direction substantially parallel 'with the plane of the wheel, and at its outer end is mounted a tool or cutter carriage 10. This end of the arm is formed into a yoke 11, Fi s. l and 3, in Which the cutter-carriage is he d, and theA longitudinal dimension of the openingof the yoke extends parallel with the axis of the arm, so that the carriage may be reciprocated in a direction to insure a radial cut.

The carria e comprises a head l2, which is opposite sides oi the head, which are prefera hanging projections 17 at op osite sides oi the head, that engade With t e upper surfaces ofthelwebs an a removable plate 18, secured to the under side of the head, 'which engages at its two op osite ends the under edges of the Webs. he up er and lower edgesoi the Webs are bevele and carefully finished, and the bearing surfaces of the overhanging projections 17 and ofi the plate 18 are correspondingly shaped to fit the said beveled edges of the webs. The under plate is secured 1n position by means of bolts 19 that screw into the head, and b the removal of which the head can be ta en fromv the yolr. The cutter spindle 14 is adapted to movelngitudinall in the head vflth the sleeve 13, and for t is purpose it-is heldI in the latter between a driving Wheel or pulley 20, which is keyed at the .upper end or' 'the s indie, and the'cutter lwhich screws on tie lower end thereof, Fig. 3.3 The cutter its) A*thread of the spindle, as the direction of rotation for the cut operates to retain the cutter in place.

To adjust theA sleeve and spindle in the head, the sleeve is provided with a rack 23,

Fig; 3, with which meshes a pinion 24 that is adapted to be manually operated. The inion is mounted en -av shaft 25 ournaledin ugs 2G that are formed on a tubular extension 27 ot the head, Figs. 3 and 5. lfhe tubular exlL ension is provided with a slot 28 Fig. 3, registering with. the rack and in which the pinion extends to mesh. -Withfthe latter. The end 29 of the shaft of thehpiiiion is squared so to receive an operating crank. Thus by actuating the pinion the cuttor-carrying` spindle and sleeve may be moved longitudinally for adjusting the cutter with respect to the work. 'lo reciprocate the carriage in the yoke `for performing the cutting and return strokes, a manually-actuated lever 30 is ar-' ranged at the end ol the arm and which con- Ynects with the bead by a rod 3l, Figs. l and 3.

The rod extends through an opening in the end-plate 32 of the yoke, and its outer end is bilurcated to receive the lever 30 to which it is hinged. The lever is fulcruined, as a lever of the first order, on a bracket 33, Figs. l and 2, and its outer end extends to a point convenient to the operator.

The. cutter-carrying spindle may be driven in any desired manner. l prefer to rotate the same by means of an electric motor 34, which. transmits power from its shaft pulley 35 to the .Wheel 2O on the upper end of the spindle by a belt or cable 36. The motor is secured on a top-plate 37 at the upper end of the hollow column 7, and is securely bolted in place, Figs. l and 2. Arranged in this manner the machine, and the power-trans,- mitting mechanism therefor, constitute a sin- 'le erta-ble structure which is readily assem- Jle on the Work or bucket wheel and removed therefrom.

in order that the cutter may be set to 'hnish surfaces of different angles, the driving belt is of sui'icient length to permit the driving Wheel on the cutter carrying spindle to assume any position within the range of angular adjustment of the cutter. An -idler is employed to take up the slack in the belt for the various adjustments and to maintain the belt in frictional engagement with the driving Wheel. In the preferred manner of running thebelt a distance pulle f 38 is provided, Figs.' l and 2, which is supported at the outer end of the cutter-car rying arm. T he belt passes from the motor pulley around the distance pulley, and the driving Wheel 2O is disposed between them, with the two lengths of the belt engaging With it at dliam'etrically opposite points. The idler 39 is arrangtd so as to o crate on the belt between the driving whee and the distance pulley and with the pertain lille 1305i tion shown, Fig. 2 the belt is running in the direction indicated by the arrow, Fig. 2. The drivingr wheel, the idler and distance pulley are arranged to rotate in a common plane, so that the alincment oi the belt in the grooves ol" these several members may be insured. As the driving Wheel is carried by the cutter spindle, any longitudinal adjustment of the latter for setting` the cutter varies the relation of the driving;l wheel to the distance pulley and idler, so that the latter have to be adjusted also. For this purpose the distance pulley 38, Fig. 2, is mounted upon an arbor l0 that is adjusted alongr its axis in a socket 41 ot a bracket 42 that is rigidly fixed to the outer end et the cutte.1cariying,r arm. By this arranffement, the distance pull ey may be raised or owered for the change in position of the driving Wheel. rlhc idler is carried at the outer end ci" an arm or bracket 43 that is arranged on the sleeve of the cutter spindle so as to be movable therewith. The idler is thus maintained in the same plane with the driving v'heel. t is angularlyadj usted, however, on tlLl sleeve, so as to take up the proper position for vany particular angular adjustment of the cutter for varying the tension of the belt. To )ermit of this adjustment7 the inner end of tie bracket for the idler is provided with an eye le that 'fits around the sleeve and by means of a set-'screw 45 carried by the eye and impinging on the sleeve thev bracket is held in 'fixed position, Fig. 2.

W hen it is desired to finish the flat surfaces of buckets ot different shapes or angles, it is necessary to accordingly set the cutter. rlhis done by adjusting the cutter-carrying arm about its axis. The point vof adjust ment is preferably between the hollow column and the inner end el the arm. 't is to be noted that the perpendicular dist-ance bctween the axis of the arm and the plane ot the wheel is constant. Hence, in order to set the cutter to operate at ditl'erent angles with respect to the plane ot thejnfheel and yet insure its moving in a radial direction on f the cutting stroke, the arm must'ibev shifted in one direction. or the other relatiwly to a radial position. rovision is thus necessary for axial and lateral'adjustment of' the arm. As shown in Figs. l and 7, a laterally adjustable carrier or support 46 is provided between the arm and the hollow column. The supporting arm is mounted on the carrier to be adjusted laterally therewith, and also to be turned axially. The column has secured to or cast integral therewith a dovetail guideway 47, the center lino ot Which is'parallel with the plane ci the wheel. The adjacent side ot the carrier 46 is provided With a dovetail projectionfi?" which interlocks in the guide-way of the'celunin. To move the carrier and the arri; supported thereon a screw 'is employed. This is supported in a lat- ;erallgf extending bracket 49 on the holler:

column, Figs. 2 and 7, and it turns freely in s bearing 51 in e bracket; butis prevented from moving therein in the direction of its axis. Y The inner end ofthe screw screws into u tapped opening of the block. 52rbolted to the side of the carrier. The outer end of the screw is squared to receive c starting-crunk, whereby it is turned for moving the carrier laterally on the columns. i

To sdjustsbly secure the erm to the cerrier the inner end is formed with s plete 53,

Figsl, 2 and 7, which is )rovided with are shaJ ed slots, 54, and bolts 55 itted with was iers 56 extend. through theslots and screw into the carrier to secure the erm to the letter. By loosening the belts, the erm may be turned to set the cutter to any positiondesired, end by tightening the bolts the erm is secured in such position. To facilitate this adjustment, the upper surfaces of the carrier and the late 53 are finished on the saine radius, en s seele is rovided on one or the other, es shown in gig. 7. The length of the src-shaped slots in the plete 53 determines the range of adjustment of the erm on its exis. Phe-se slots muy be ranged to permit of the maximum adjustment of the erin, but in the present cese, s. second point of adjustment 1s yprovided for increasing the rango. `For this .purpose the erm is mede in two sections, en inner section '57 end en outer er "yoke section 58, i

and 7, The adjacent ends of the sections ere 4termed 'with plates 59 end 60, und 'the' adjustable connection between them is simi ler to that between the carrier it end the in ner section of `the arm. 'The sections ere, therefore, independently edjustebie.

ln operation the erm is first adjusted on its exis to obtsin the proper envie for the exis of the cutter-carrying spindle. After this is esceitsined,4 the erm is adjusted leterelly and the cutvterspindle adjusted longi tudinelly relatively to the Work, and these adjustments are mede by trici until s posi tion. of the cutter is arrived et that will insure s perfectly radial stroke for the cutter end e, out of the properdepth. The cutting stroke begins et the outer end of the bucket, end to make the stroke the opera-tor presses the le ver which moves the carriage with the cutter inwardly on one bucket at c time. When the root of the bucket is reached the stroke is reversed by theo ierator, whereby the cutter is returned to the storting iositiou. The machine is thon turned c suil icient distance to pro-sent the cutter to the next `bucket to bo in turn Iinished. ln this manner the flut surfaces ol' .sil the buckets on one side of the Wheel :1ro -iinishod successively. After they erciinishcrl, tho machine is removed from the wheel by the shop-crane, the wheel tu rnod over, und the machine replaced in position. As the ist surfaces on the second sido of the wheel srs disposed et e. corre spending angle to e perpendicular to the' plane of the Wheel, the erm has to be turned ou its axis so that the cutter msyoperate et thepro er angle.' After its adjustment isl i'sces o'r' the -bucketssre all vfinished 'st e uniform angle, and es no adjustment of the cutter is necessary sfter beginning the operation of finishing, the buckets ere pre served uniform in size.

The invention 1s shown in connection lwth s turbine Wheel com osed of a, fiat disk with integral and ra islly extending buckets. When cest motel uckets are to he machined, the ring or segment thereof can either be mounted on the wheel that is j,

to carry them or upon a suitable support. This support muy bein the form of 's disk, ring or segment theref und should coniorm es closely es possible to the normal wheel. The machine may also he used to inish the so-celled stetionury or intermediete buckets, Suitable `modiueetions mcy-ne made in the machine to `permit ci finishing buckets ci other construction than that shown.

In accordance With the provisions of the patent ststutes, lheve described the principie of operetion of my invention, together with the sppiiretus which l new. consider tc represent the best'embodiment thereof; lout l desire to' have it understood that the ep eretus shown is only illustrative,

movably mounted on the column shove the work, means for adjusting the cerrier rectilineerly in s, direction trsnsverse the exis oi the column in e piene 'pereilel' thereto, en crm sdjustsbly attached tothe carrier sind projecting thererrcm 'et right sngles tothe jp ene of adjustment moons for singularly adjusting the arm about en,

axis trsnsverse to the exis of the column s tool holder carried by 'the outer end o the erm, ineens for adjusting the Position of the toolI holder with respect to tnewerm, end s motor supported by the couinn which drivesy the tool.

2. In e machine ot' the character described, the combinston ci s supporting coiumn, e radial cutter-carrying erm revolusly meinstn ed thereon to turn shout the exis of the column, und ineens for edjusting the erm toV 4secujoy positions joeruilel to sind en either side'oi e redini position..

nal movement on t secured to t e hollow column to rotate there- `w1th, means .between the arm and hollow @legale 3. In a machine oi the character described, the combination of a supporting column having a base which is adapted to rest on the work, a tool-carrying arm revclubly supported on the column, a tool carriage arranged to reciprocate longitudinally on) the arm, means forshifting the `arm laterally and parallel to a radial position, and means for angularly adjusting the arm about its axis.

l. ln a machine of the character described, the combination of a supporting column, means for supporting the work with respect to the axis of the column to permit of a relative turning movement,` an arm carried by the column, means for shitting the arm l laterally in a plane at right angles to the l axis of the column, means for angularly adjusting the arm on its axis,.and a tool-carriage operatively mounted on the arm.

' 5.111 a machine of the character described, the combination of a hollow column which is adapted to be mounted on interchange able supporting columns for work of dii'lerent sizes, a radial arm arranged on the hollow column, means between the column andthe arm which permits the latter to be adjusted laterally oi and also around its axis, and a tool carriage Ioperatively mounted on the arm.

6. l'n a machine of the character described, the combination of a supporting column suitable for work of a delinite size, a hollow column adapted to lit the supporting column, a ball-bearin between the columns, an arm column for adjusting the former in a lateral direction, means for adjusting the arm on its axis, and a tool-carriage on the arm which i adjustable and is adapted to be reciprocatedaxially of the arm.

7. ln a machine for performing milling operations adjacent the edges4 of disk-like pieces of work, the combination of a supportmg column at the ceu er of the work, a hollow column assemble thereon, an antifriction bearing between the columns, an arm movably mounted on the hollow column which extends parallel to the lane of the work, a tool carria e mounted fldr longitudie arm, a rotary tool carried b the carriage with its axis of rotation at right angles to said longitudinal movement, means for driving the tool, means for adjusting the arm together with the carriage and tool about an axis at right angles to the axis of the column tomachine surfaces inclined at different angles and for adjusting them arallel to themselves after such engular adjustment to cause the longitudinal movement oi the tool to be substantially radial with. respect to the colunm, and de-l vice for moving the carriage and the arm.

8. ln a machine of the character described, the combination of a supporting column, a cutter-carrying arm, a support between the arm and the column, a carrier between the l arm and the support, means for adjustingr the carrier laterally on the support, and means for adjusting the arm around its axis on the carrier.

9. In a machine of the character described, the combination of a supporting column, a hollow column assembled thereon, a dovetail way provided on the hollow column, a carrier mov'ably supported in said way,` means for adjusting the carrier laterally an arm secured to the carrier to move thorewith, means for adjusting the arm about its axis on the carrier-,and a tool carriage operatively mounted on the arm.

10. In a machine of the character described, the combination of a column ada ted to be arranged centrally on the Work toibo finished, a radial arm supported thereon, e carrier between the column and the arm, a dovetail connection between the carrier and the column, an adjusting screw supported by the column for moving the carrier and the arm laterally on the column, means for permitting the arm to be adjusted axially on the carrier, and a tool carriage operatively mounted on the arm.

11. In a machine of the character described, the Acombination of a central eupporting column, a radial arm mounted thereon to turn about the axis of the column, a tool carriage arranged on the arm which is movable longitudinally thereof a cuttercarrying spindle mounted in the carriage which extends transversely to the axis of the arm and at an angle to the axis of the column, a cutter'on the spindle, means for adjusting the indie longitudinally in the carriage, and evices for adjusting thc arm together with the about the axis of the arm and also laterally in a direction at right angles to the column to cause thc longitudinal movement of the cutter lr-o be in a substantially radial direction with respect to the su porting column.

l2. In a machine of t 1e character described, the combination of a central supporting column pivotally mounted to move about its axis, aradial arm mounted thereon, means i'or moving the arm transversely of the column, a cutter carriage mounted on the arm and ada )ted to move therewith about the axis ol the column and also longitudinally oi' the arm, means carried by the arm for reciprocating the carriage, a cutter-,carrying s indie mounted in the carriage, a cutter on t1 e spindle, a source of power arranged on the column and movable therewith, and means for transmitting power from said. source to the spindle.

a machine oi the character described, the combination of a supporting colin the way,

carriage and spindle angularly umn, a radial arm-mounted thereon and coinposed of two sections which are independentlyadjustable about the same axls, a yoke formed on the outer section the axis of which Versely to that of the arm, a cutter on the spindle, and means for rotating the cutter.

14. In a machine of the character described, the combination ol a column, a radial arm adjustably mounted thereon, a yoke formed at the outer end of the arm, a carriage movably mounted in the yoke, a rotating cutter-carrying spindlein the carriage, 4a manually actuated lever carried by the arm, and a connection between the lever and the carria e.

15. 1 n a machine of the scribed, the combination ol' a column, a radial arm adjustably mounted thereon which is provided with a yoke, means lor adjusting the arm transversely ol' the column, a carriage which is movable in the yoke in the direction of the axis o l the arm, a sleeve in the carriage which extends transversely to the axis ol the arm, a spindle rotatably mounted in the sleeve, a cutter on the spindle, means for adjusting the spindle and sleeve together- 1n the carriage, and a manually operated de-y vice carried by the arm for reciprocating the carriage and cutter during the cutting strokes.

i6, A milling machine adapted to be bodily supported andmovably mounted -on the work, the same comprising a column supported on the work, an adjustable cuttercarrying arm on the column, ineens lor adjusting the arm laterally, a carriage mounted for reciprccation on the arm, a cutter-carrying spindle in the carriage, a motor sup-- ported on the column, and a power transmitting device between the motor and the spindle lor rotating the latter, said device includcharacter deadjustably mounted on the carriage, a driving wheel on the spindle,` a motor supported to revolve with the arm, a belt driving connection between the wheel andv motor, and

,means for maintaining said connection in.

operative relation to the Wheel for all positions of adjustment of the cutter-carrying spindle.

18. ln a machine of the character described, tlie combination of a supporting column, a radial arm which is revolu bly mounted thereon and is capable of 'lateral and axial adjustment, a carriage on the arm which is adjustable therewith, means for reciprocating the carriage longitudinally of the arm, a cutter-carrying spindle on the carriage which extends transversely of the arm and is longitudinally adjustable, a motor secured in lined position on the supporting column, a shaft pulley lor the motor, a' distance pulley adjustably supported on the arm, adriving wheel on the spindle which is movable there-l with, an idler arranged in a common plane with t lie wheel and distance pulley and movable witli the former, and a driving belt eX- tending from the motor pulley to the distance pulley and operatively engaging with the driving wheel and idler.

ln witness whereof, .l have hereunto set my hand this 15th day of April, 1905.

' JOHN lllDDELL. Tvl/'-i'fi1e-sisersz BENJAMIN ll. HULL,

HELEN Gaiman.

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