US1892453A - Apparatus for centerless grinding or polishing - Google Patents

Description

Dec. 27, 1932. I R. w. FULLER y 1,892,453

'APPARATUS FOR CENTELESS GRINDING OR PQLISHING Filel Jan. 20. 1927 4 Sheets-Sheet 1 0 i0 2323i f l' j# r.- alf/AU..

Dec. 27, 1932.

` R. w. FULLER APFARATUS Fon cENTERLEs's GR-INDING on PoLIsnING Filed Jan; 2.o. 1927 -4 sheets-sheet 2 K mx.. SQ Nm Q R. W. FULLER Dec. 27, 1932.

'APPARATUS FOR CENTERLESS GRINDING OR POLISHING- I Filed Jan. 20, 1927 `4 SheetS-Sheet 3 De@ 27, 1932 f R. w. FULLER Y 1,892,453 APBARATUS Fon `cENTERlkass GRIND ING oh POLISHING 'Filed Jan. go. 192'/ .l 4 sheets-sheet 4 A erably ilTthe torm of a mov'ng belt, the work Patented Dec. 27, 19,32

PATENT OFFICE Q RUF'S W. vFULLER, vO11" DEERFIELD, MASSACHUSETTS, ASSIG'NOR T0 PRODUCTION MACHINE COMPANY, GREENFIELD, MASSACHUSETTS, A CORPORATION 0F MASSA- cHUsETTs APPARATUS ron oEN'rERLEss saumure on PoLIsHING Application lcd January 20, 192i. Serial No. 162,300.

'Ihe present invention relates to methods and apparatus for centerless grinding or .polishing and more particularly to methods and machines adapted for grinding or polishling taper Work.

The object ot thc present invention is to provide a method and machine by which either taper or straight work may be ground or polished without the `necessity of chucking the work or mounting it on centers.

With this object in view, Athe present invention consists in the method andimachine for grinding or polishing as hereinafter described and particularly defined inthe claims. Y

In the accompanying drawngs, Fig. 1 is. a side elevation. partly in section of aimachine embodying the several features of the present invention; Fig. 2 is a front elevation showing so much of the machine as is necessary to an understanding ottlie present invention; Fig. 3 is a plan view of the machine shown in Figs. 1 and 2: Figl is a rear elevation of the work rest :'Fig. 5 is a. detail view in section on line 5 5 of Figs3; FigQG is a. detail in sect`on online 6 6 of Fig. 1-; Fig7 is a diagram in plan illustrating the operation of grinding or polishingwith the machineot the present invention; Fig. 8 is a diagram smilar to Fig. 7 but taken in front elevation; Fig. 9 isI a diagram in plan'illustrating the operationof taper grinding Without transverse feed Fig. 10 is a front view of the belt tensioning mechanism: and Fig. 11 isa side view of the belt tensioning mechamsm.

-. The preferred embodiment of the present invention comprises an improvement ontlie machine disclosed in the Blevney patentQNo. 15594.445, dated `August 3; 1926,' in which the grinding or polishing of straight Work is effected by means of an abrasive element prefbeing fed over a suitable Work resttransversely of the abrasive elementl by a sutable work holding andfeedmg dev1ce.j- This device, which may consist of a rotating roll,

causing the transverse movement of thewvork', .for which latter 4purpose the roll is inclined with respect to the center line of the Work.

about an axis substantially perpendicular to the plane of the abrasive element.

The principal feature of the present invention consists in means whereby the work holding means is mounted to permit an automatic recession thereof romthe belt in order to accommodate work of changing diameter as successive portions pass into engagement with the abrasive element. This feature perm'ts the grinding of tapers, the work holding f means automatically.increasing its distance from above as the work passes through the machine. l e' In addition to the adjustmentl of the Work holding means about an axis perpendicular to thc abrading surface yfor the purpose ot feeding the Work, a further feature'of the present invention contemplates an adjustment thereof about an axis which is substantiallyf parallel to the abrading surface in' order that its engagement with the-work may conform to the work -surfa e, particularly whentapers are to be gom or polished.-

Referring to the drawings, the illustrated embodimentl of thepresent invention com prises the abrasive belt 10 and the bacling or cushionbelt 12 which are 'caused totravel in the direction of the arrow of Fig. 1.v The :backing belt 12 passes over the platen bars 14 which aresupported on a carrier 16, and mounted :Eor suitable movementptoward .and from the belt as described in above mentioned Blevney patent. The' work 18 is supported on a work rest indicated generally by 20 during 'the' polishing ,or grinding operation, and is maintained 'in engagement withthe belt by meansof the rotating feed` roll 22,- constituting they work holding `and yfeeding means. The feedroll is covered with leather orj rubber and'is rotated inthe direction of lthefarrow in'order to rotate the work and presentfall portionsthereof to the belt. The

feed roll22 isn-mounted ina. feed roll house which are driven lfroma pulle-y28 connected by a belt 30 ywith a source of power, the belt f being maintainedtautby a tension or takeing 22f and is rotated by means ofgears 26. serves the double function ot .peripherally` supporting thework to maintainitin engagement `with the abrasivev -element and 10Q up means hereinafter to be described in detail. .The feed roll housing is provided with j bearings 32 to receive trunnions 34 extending from opposite sides of a vertical supporting plate 36. The' feed roll housing may be adjusted to .different angular positions by rotation -about the a'xis of the trunnions 34 which axis, it will be seen, is perpendiculOp-lar to the abrading surface of the belt 10.

The housing is maintained in adjusted posi tion by bolts 38. Thisinclination of the feed roll is for the purpose of imparting a longitudinal motion tothe Work as it passes over the work rest. The details of the abrasive element and the feed rollthus far described vare similar to ,those described in the above mentioned Blevne",7 patent.

In order to permit grinding of tapers, pro- A vision is made for adjusting the feed roll about. an axis parallel to the abrasive surface,

that is to say, a vertical axis in the illustrated machine. Provision is also made for permitting a recession of the feed roll from its initialposition during the grinding operation `in order that the taper work with its changing diameter may pass over the work rest Abetween the feed roll and the belt.

To these ends, the plate 36, which constitutes a support for the feed roll assembly,

is formed with a base 40v to the bottom of which is secured a. post 42 received in a suitable bearin in a' carriage 44. The base 40 rests upon t e to of the carriage 44, and is secured in any drdsired angular position lby means ofva..bolt46 threaded'into the carriage 44 and passing through an arcuate slot 48 in the base l40. In order to .pxevent accidental removal of the feed roll assembly from the machine, the post 42 is formed'with an annular groove 50 into which extends the end of a screw 52 threaded into the'front of thev carriage 44. It will be seen that the center line of the post 42 is the axis about carriage assembl vguide piece being formed integral with .the

slide bearing 54, and the latter being adjustably-attached tol the bearing by means of bolts 68 received in the bearing and passing through transverse slots in the guide 66. The

guides engage withthe' carriage on inclined surfaces to'maintain the carriagein p roper vertical position. p, One 'of the guldes is cut away to provide a locking piece 70, which may be forced a ainst the side of the carriage by means of a hand screw 72 to retain thecarriage in any\desired adjusted posi tion, as inl the grinding or polishing of straight work where no movement ot' the carriage is necessasry. A curtain 73 secured to the carriage and passing over a roller 74 journaled in the forward end ofthe slide bearing protects against entrance of dust into the moving parts. The free end of the curtain is provided with a weight 7 5 to hold it taut.

The supports for the various parts are described as follows: The slide bearing 54 is bolted toa table 76 extending transversely across the machine and the table is secured to a plate 77 which is formed integrally on the end of a vertical post 78. The post extends through a hole in a block 80 and the table with itsassociated mechanism is supported on the block by a collar 82, which is locked i to the post 78 by a set screw 84. The block 8O is firlnly'supported upon the main column 86 of themachine by two posts 88 which are secured to the column, and on which the block l 80 is slidingly mounted. In order that the entire assembly may be adjusted toward and from the belt, a rotatable screw 90 is received in the block 80 and has its end journaled in a bracket 92 secured to the column 86 between the two posts 88. A hand `Wheel 93 is used to impart rotation to the sc'rewin order to adjust the position of the table and its associated 'mechanism with relation to the belt. A curtain 94 similar to the curtain 73 is attached to the rear end of thecarriage to rotect the guides.

n order to maintain the feed .rollin proper position with respect to the work and to the belt as the grinding proceeds, a cord 95 is secured to the rear end of the carriage 44 by means of a bolt 96Awhich is received in a slot in 'the carriage. From the rear end of the carriage the cord draws forwardly and passes over a pulley 98 downwardly to a second pulley 100 andthence to the left side over a pul-v.

ley 102 journaled in the extreme left-hand `end of the table. A weight 104 is attached to the end of the cord and acts to draw the carrlage and its associated feed roll assembly toward the belt. The. weight, being placed in .the position shown, also serves to counterbalance the feed roll assembly and to revent unbalancing of the table which might impart excessive. stresses to the supporting posts. A stop 106 which projects upwardly, through a slot108 in the bottom ofthe guide limits the forward movement of the carriage by engaging with the rear end of the latter'. The stop is provided .with a horizontal plate 109 which bears against the un-dersurfacc of the guide and which is secured in. any desired position by means, of a bo1t"112 assing upwardly through the s1ot108 an enmoana of the table is a plate 116 which is formed integrally with a bushing 118. 'Ifhejwork rest -supporting post 120 is received in the buslimg and has circular rack teeth 122 formed on its lower end. The circular rack engages with a pinion 124 which may be'rotated by a hand wheel 126 to Araise or lower the post 120. Moreover, the post may b'e-rotatedy about its axis to present the work rest in various angular positions with respect to the belt. The bushing is slotted transversely at 128 and also longitudinally in order to provide means for clam ing the post 120 through the medium of a ock screw 130 as will be obv'ons. The post extends outwardly from the tab e) at such an angle that racking of the post will produce a horizontal movement of the work rest which is about one-half of the vertical movement.

, A mounting plate 132 is secured at the upper end of the post 120 and a work rest support 133 is pivoted on the 'mounting plate by means of a stud 134, provision being made for locking itin. any adjusted position by means of a bolt 136 secured in the mounting plate and passing through an arcuate slot 138 in the support. The bolt 136 is positioned beyondthe outer edge of the abrasive belt,

j where' it is .conveniently 'accessible' for adjustment. The work rest proper consists of a plurality of freely rotatable rolls mounted on a'pintle 142vwhich is journaledin a frame 144 secured by screws 146 to the support 133. The rolls are maintained inspaced relation `by intermediate projections 147 formed integral with the frame 14,4.

.The work rest is therefore capable of four adjustments,'-iirst, a combined vertical and horizontal movement accomplished by racking the supporting post up or down; second,

a horizontal movement effected by'bodily ad justment of the machine bed by actuation of the hand wheel 93 ;,third. an inclination on the pivot 134 which is on an axis perpendicular to theabrading surface; and fourth, an angular adjustment between the plane of the work rest and the abrading' surface accom'- plished by rotating the supporting post 120 1n its bushing.

The first of these adjustments is of-es cial value in grinding Ystraight work, cause if the diameter of the work is changed, the work rest may be moved in one operation to a position which is horizontally the correct distance from the belt and vertically correct to position/the center line ofthe work at the proper level. If it is desired to` make independent vertical and horizontal adjust- -ments, the rest is first moved to its proper 'vertical position byrth'e supporting post, and its horizontal position-Mis determined by the work rest andJ thel belt.

portance in fine polishing, as willI hereinadjustments, it will be noted that a rotation of the post 120 will produce a corresponding tipping of the work Test due to the inclination-of the post from the-vertical, but this tipping is ordinarily of no conse uence, and if necessary, may be compensate by an adjustment on the pivot 134.

In the operation of the machine the platen bars 14 are brought up against the belt and ,are secured in position as described in the inding straight work, the operation is identlcalwith that described Blevney patent. For

in theBlevney patent. The'work rest is adjusted so that the center line of the work is slightly lower than the center of the feed roll. y

The feed roll carriage ismaintained stationaryby means of the screw 72. The work rest is positioned somewhat closer to the belt than to the feed roll inorderlthat thework -The adj ustmentabout the pivot 134 is of im- .l

after be described. As for the fourth of these v 'lol may not be jammed or cramped between the In order to cause feeding of the work through the machine', the feed roll is tilted on the trunnions 34, the axis of rotation of the roll, however, being maintained parallel to the abrading surface.

It is to be noted thatfor adjustment to di/fferent sizes of straight work it is preferable to move the table as a unit by means of the hand wheel 93 rather tha-n to lmove the carriage by loosening the screw 72. This operation moves both the feed roll and the work rest as a' unit toward or from the belt, but if the changes are such as toy necessitate independent adjustments of the feed roll and the work rest, they may be effectedv by moving the feed roll carriage in theslide bearing and by rackng the Work roll supporting post up or down.

For grinding taper work, the'machine is adapted for use in two ways,-irst, with transverse feeding of the work; and second, without feeding. .In the first case, the parts are arranged as diagrammatically shown in Figs. 7 and 8. The work rest may be adjusted to any suitable position aboutthe pivot 134,

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being arranged for the operation illustrated in Fie' 8 so that the axis of the work is horilel to the' belt as'indicated by the dotted line 2O()y in Fig; 7, and is ositioned between the belt and the center o the smallest diameter of the work to be vground, in order that the worlinay not be cramped or jammed by fa'll- Vertically the work rest is arranged so that vertical axes which arerespectively desi- I )n'ated at,202 and 204 of Figs. 7 and' 8. A 65 second of the above mentioned adjustments. justment about the verticalaxis 204, which 130 ving between the work rest and the feed roll.

zonta. The plane of the work rest is'paralis the asis of the bearig :isos-,45s

post.42, is made so vent passage thereof through the machine that the angle of the fee roll with respect or wherethe work is of extreme taper. .In' to the belt may be made to conform to the this case, ithe parts are placed as shown in surface of the taper as shown in Fig. 7. The Fig. 9. The work rest is preferably arranged amount of inclination on, the horizontal axis at an angle with respect ,to the beltasshown .70 202 is suicient so that the axis of rotation by the line 20G-which is parallel to the center of the feeding roll and center lilieof the line of the workrbut somewhatneare'rfY the ment of the. work and the fee work are oblique tos eachother, .the rate of beltthan the feed nroll. The feed rollis ad. feeding being determined by the inclinationl )usted about its vertical axis 204` so that it between these lines. Although theengage-` contacts substantially .throughout its'entire lroll is a int length. with an elemental line of the taper.

' of contact because of the inclination o the This mayrequire that the axis of rotationroll with respect to the axis of the work, the be maintained substantially-horizontal, that adjustment of the roll about its taper axis i`s,without tilting 'on the- axis 20,2 but', espe- 204 insures a uniform pressure of t e work cially in thecase of large taper it maybe against the belt during the entire grinding adjusted to lie parallel to thecenter line of operation. The carriage is unlocked by the work, and atan angle from the horizonloosening the screwj 72 and the sto 106 is tal. The feed roll carriage, is preferably adjusted to such a position that at t e comlocked in position` by th IOCkig Piece-70- mencement of the grinding operation the feed `(Inthis(operation, no transverse 'feeding' 516-' roll will be at a distance from the belt exactly v*tion takes place, the feed roll merely rotati suicient for receiving the small eid of the ing the work` against fthe"I abrasive ele'` work. The work is preferably started with inent. Because of the fixed position'of the a'considerable portion of its len 'against the work, however, by the action of\o rationsvand to cross the feed .roll-areshowi infulllinesinFig'. 7 for intoan angular position about the axis ,ofthe x the ycommencement of the grinding operation 'stud 134. This gives a high lusterand climi-r gth in engage- =fed roll/carriage, this operation permitsA ment with the abrasive belt. f i grinding of tapers with considerable accu- As lthe grinding progresses, the feed roll racy ,although the length of the work ywhich performs the twg-fold function of holding can be successfully ground is limited by the the workagainst the belt and'adva'ncing it width of the belt. from left to right. As `the work advances, While the work rest is preferably maint moves with ,its axis always parallelto it- @tained horizontal for normal work, the piv-- self, and because of the increasing diameter otaladjustment. on the stud 134 is' a'feature of' the work, the feeding action causes the of importance lforpermitting'fine .polishing f feed roll carriage to be moved Vforwardlyor on soft metalssuch as brass. In this case, it is away from' the belt, being 'pressed' firmly desirable to perform a pluralitylofhpolislhing is ingin s. the weight 104. The work'is therefore moved. o this end, the`work isiirst through he transversey of the feednroll, and the feed' machine with'thework restin a substantially roll Ais m ved f longitudinally by the work; horizontalL position and is passed through The relative positions of the' work and the a second time after'therest'hasbeen adjusted andin dot and dash.y lines for the conditioAn L nates any polishing marks on the work. f

when fthe work has progressed part way. It will'be apparent from thef .diameterbf the latter, and as'th grindingv automatically discharged from the rightl ofthe weight.

1 Emplo 'work wit out feeding is useful in ca'ses where its outer end a' counter balance`- w 6.5-

work, inforder that 'the roll may not have out of engagement with the work rest. At

for another grind Oregomg de: through the machine. At the commencementl 'lscription that 'during polishin vand grindf of the operation, the point of contact of the` ing of taper work. a considerab @latitude of 110 feed roll and the wo k occ 'rs at thex smalll vmovement is required' for the belt 3 0 becausev `of the movement of the feed roll cariia e-and the necessary tip ing of the feed( rol .Y To( 'the @dft-har the galego may/be maintained taut under all conditions, "the vtakeup'means` 115 illustrated in Figs. 10= and 11 is emploed.'`-` The belt 30 passing over the feed roll pu ley`-r 28is driven by a'pulley 160 fast on a shaft 162., which is journaled in'a bracket 1641secured ai bya post 166 to .l the main columnJ of the in a- 120 cliine. A driving pulley 168connected'with s roceeds this oint of contact occurs on lower evels with peet to the workI axis and on higher levels with .respectjto'the feed roll ams.'w It is desirable that the point of contact be maintained at alevel not higher thanthe axis of the feed roll for all positions of the `any tendencyf to :force the work upwardly the completion of the operation, the work is P rotate the. shaft 162.' Anf idlerarm '170 hand side of the machine and-thelcarriagis formed integral fw'ith ,a hub .172 which is restored to lits-'original position iii readiness loosely received on the shaft :162, carrieatwo 125 ingj operation by'tlie action spaced idler'pulleys 17 4( overlwhich the belt 30 passes;4 A'counterbalance armll-galso formed-integrakwith the hub 172,'carries at ei ht 178 the work hasprojections `which would pre-' which acts to maintain-the ridler pulleys in 130 ent of the mithin@ to grindip'r,

any suitable drivingmeans is 'employed to i engagement with l'the belt in a manner to maintain the belt taut under all conditions.

The wei ht is pivoted on the arm 176 by means o a stud 180. The position of the part when the yfeed' roll is in itsrearwardmostl position, viz, its position ne rest the abrasive ,'belt, is indicated in full ines in Fig. 11. Drin the operation of grinding taper work,l the feed roll carriagemoves forwardly so that the feed roll pulley 28 may finally take the position indicated'in dot and dash lines. The positions of the belt 30 and the counter balance arm are also i lustrated for this position by dot andfd'ash ines. It

-will be seen that by the employment'of two spaced idler pulleys which are capable of simultaneous movement on the idler arm, the belt may be maintained taut by a movement of the lidler arm which is 'only half of that which would be necessary' if only a single to a lmore nearly vertical position, where the counter balance 178 exerts a decreased tensioning force. In order to permit the counter balance to approach more closely this vertical position upon raising of the counter balance arm, the weight .is'grooved at 182 to provide a recess into which the arm may enter.

The above arrangement of the belt take-up mechanism provides for -suicient pressure of the idler pulleys against the belt for proper,

tensioning ofthe belt under all conditions any axis. The id er pulleys 174: are arranged sufficiently above the feed roll pulley 28, and the belt 30 is of suicientl length so that the belt may pro rly enga e the grooveof the feed roll pu ley even t ough the latter isA tipped to a considerable angle. In order to eliminate any 'possibility of disengagement of the belt and pulleys however, the latter are formed with deep the belt is of comparatively small cross section, fitting snugly within the grooves of the pulleys;

It will be seen that an important feature inl connection .with grinding-of tapers consists in the provision for `mounting the feed roll for adjustment `about two axes, one of which is substantially perpendicular lto the abrasive element, and the othe` of which is Y Y Y substantially parallel thereto. Stated in an- .other way, the tipping axes of the feed roll -shaped grooves and diameter. independently of the movement of the car-l riage or of the tipping of the'feed roll about tiall perpendicular to the axis yof rotationof the eed roll. f

It is to be understood that the inventionl is not considered to belimited to the specificconstructionherein shown and' described but may be varied insofar as iti does not depart from the scope of the appenledxclaim's. 'It is within the purview of the invention, for example, to employ7 an abrasive element in the form of a grinding roll in place of a travaremutually perpendicular and yare substani elling belt, in which case the positions ofthe v axes which are defined as being respectively per endicular and parallel to the abrasive sur ace, will be considered to be substantially perpendicular and parallel to a" tangent plane of the abrasive surface atjthe position of Contact of the abrasive element with the work. f

Having thus describedthe invention, what is claimed is:

1. A grinding or polishing machine havi ing, in combination, a vrork rest, an abrasive element, a work holdingy and feedingdevice to engage peripherally with thework and to feed it transversely of the abrasive element,

and meansfor mounting. the@ abrasive element andthe work holding'y and feeding device having provision for recessive movement between them, and means for causing relative movement between the vwork holding and feeding device and the abrasive element as' 'the grinding or polishing proceedsito accommodate taper work.

2. A grinding or polishing machine hav# ing, in combination, a work rest an abrasive element, a work holding device for peripher Aally supporting the work, and means for rotatably adjusting the work holding device about an axis substantially parallel to the direction of movement of the abrading sur- M face to accommodate work of non-uniform 3. A grinding 'or polishing machine having, in combination, an abrasive element, a work rest, feed roll for peripherally supporting the work in engagement with the abrasive element and for feeding the work trans versely of the abrasive element, and means for causin recessive movement of the feed of the work to accommodate work of nonuniform diameter.

roll from t e abrasive element during feeding 4. A grinding orpolishing` machine-having, in combination, an abrasive element, a Work rest, a feed roll for feeding the work transversely of the abrasive element and for maintaining it in engagement therewith,

means for adjusting-the inclination of the'- feed roll about'an axis substantially perpen- -dicular to the abrasive element, and means for mounting the feed roll having provision 'for progresslvely varying the dlsta-ncebetweenthe feed roll and the abrasive element to accommodate 'work iof changing diameter. 1.30.`

5,. A grinding or polishing machine havlng, in combination, an vabrasive'element, a

work rest,v a feed roll for feeding the work,

transversely .of the abrasive felement and for maintaining it in engagement therewith, means for adjusting the inclination of the feed roll about an axis substantially erpendicular to thev abrasive element,an means for causing the feed rollte recede from the abrasiveelement as the grinding progresses to accommodate work of increasing/diameter.

6. -A grinding or polishing machine having, -in combination, an abrasive element, a

work rest, a feed roll for feeding the work transversely of the abrasive element and for y maintaining it in engagement therewith,

i means for adjusting the-,inclination of the feed roll aboutan axis substantially perpendicular'to the abrasive element, means for rotating the feed roll, means for slidingly mounting the feed roll, means for progressively movingthe feed roll from or toward the abrasive elementl as the grinding rogresses, and means for maintaining the eed roll in engagement with the work irrespective of the variations 'in diameter of the work.

7. A- grinding or polishing machine having, in combination, an abrasive element, a

, work rest, a feed roll, means for rotating the lto slide back and forth with relation to-the abrasive element,,a support for the slide bearing arranged atv one side of the bearmg, a

' weight and connections-therewith for, maintaining the feed roll in engagement with thel work, the weight being positioned at the opposite side of the`support on the slide bearing to counter-balance the latter. 9. lA grinding or polishing machinehaying, in combination, an. abrasive element, a feed rolladaptedl to en age the work on the oposite side from t e abrasive element and aving' rovision for tipping.. about mutually perpendicular axes which are substantially perpendiular to the axis of rotation, awork rest, a supportfor the feed` roll lnavmgz;` rovision for permitting bodily recession o the feed roll from the abrasive element-'for grindin orlpoli'shing tapers, and means Iforv maintaming the feed'l roll in engagement with the work during the grindingorpolishingfoperaftion; f

.ing, in combination, an abrasive e1'ement, a an angular adjust/mentL of, the plane of the v10.` A grinding or polishing machine l havfeed roll to feed the work transversely of the abrasive element, a work rest, a slide bearin for the feed roll, means fr causing the feed roll to lrecede progressively from the abrasive element during feeding of the work toY accommodate taper work.

ing, in combination, an abrasive element,a work rest, a feed roll to feed` the work trans,- Jverselyof .the abrasive element, a vfeed roll housing pivoted on an axis substantially perlL- Agrinding or polishing machine havpendicular to theabrading surface', a'carriage f on which. the housing is mounted, a slide bearf ing in which the carriage has provision for longitudinal.v movement toward and away from the abrasive element, and means for causing progressive movement of the carria on the slide2 bearing asthe feeding of e work proceeds to or polishing of taper articles.

12. v A' grinding ori-polishing machine hav- `ing, ingcombination, an abrasive element, a work rest, a feed roll to feed the work transe versely of the abrasive element, a feed roll carriage, means for mounting the feed roll on the carriage having provision for tip ing of the roll on axes substantially perpen icular and parallel to the abrading slwxrface respectively, anda slide bearing in which the' l 'carriage is free to move toward or away from the abrasive element during transverse 'feed of the 'work to permit grinding o1" polishing of tapers. .V5 v 13. A grinding or polishing machine'having, in combination, an abrasive element, a.

Work rest, a feed rollto feed the work transversely of the abrasive element, means perfnittng tipping of the feed rollun mutually .perpendicularaxes which are substantially eifldiczular to the of rotation .of the roll, a sliding 'carriage on which the feed rolLis mounted and adapted o move away from the abrasive element during feeding and grinding of taper work, and means forvlocking the carriage for of straight` work or of ta er work without feeding. 14. 'A grin ing or polishing, machine having, in.' combination, abrasive lelement, a

` work restpmcans'for maintaining the workin engagement with .the abrasiveelement, and ,means for adjustingthe work rest to diierent1angular positions to vary the angle bef ,the work rest andA the' i machine havatable for supporting the feed rolhav work rest,- work rest supporting meansv f 'extending outwardly from the table and con- I structedand arrai'aged` Lto eie'ct a simultaneous vertical and-horizontal adjustment offthe' work rest, and means for mounting thewrk i rrest supporting mean'shaving provision for belt.

work rest with respect to the abrasive element.

16. A grinding-or polishing machine having, in combination, an abrasive element, a

-feed roll, a table for supporting the feed roll,

a work'rest, a work rest supportingpost extending on an angle from the table and toward the abrasive element, a .bushing secured to the table, a rack'formed on the supy porting post, a pinion engaging with the rack `mitting turning adj ustmentsJof the work rest, and means for clamping the su ported post.

18. A work rest for a center ess grinding or polishing machine, comprising a series of. rollers with which the workengages a pintle having its axis below and substantially parallel with the work on which the rollers are mounted for free rotation, anda support for the pintle. l

19. A work rest for a centerless grinding or polishing machine, comprising a su porting plate having a plurality of upwarly extendin projections, a intle extending throng the plrojections, an a series of freely rotatable ro ers mounted on the pintle be'- cient pressure tomaintain the belt positions of the feed roll.l I

'22. A grinding or polishing machine having, in combination, an abrasive element, a work holding and feeding device, a carriage taut at an to permit movement of the work holding and feeding device with respect to the abrasive element, a belt for driving the work holding and feeding device, means for maintaining the belt taut at all positions of the carriage including an idler pulley anda counter balance, and means for mounting the counter balance having provision for permitting a decrease in the tensioning effect on .the belt as the carriage recedes from the abrasive element.

In testimony whereof I have signed my name to this specification.

RUFUSFULLER.

tween the projections :for supporting the l work.

20. A grinding or polishing havin, in combination, an abrasive element, a wor holding and feedin device,` a ulley 'for thework holdingmn feeding i)evice, means permitting lon itudinal and inclined movements of the yvorV holdin and feeding device, a belt associated with le pulley for operating the device, means for maintaining the belt taut including spaced idlerpulleys adapted forv simultaneous movement, and

machine .j

means for maintaining the idler ulleysin engagementwith oppositesides o 4the belt and under suicientpressure to tension the 21. A grinding or polishing machine having, in combination,'an abrasive element, a l feed roll, a feed roll carriage to permit movement of the feed/roll .with respect to thev abrasive element, iieansv permitting inclination of the feed roll, a belt for driving the feed roll, an idler arm, a pair of'spaced idler pnl-- -leys mounted on the vidler arm and adapted' for simultaneous movement, and a counter-9 balance associated with the idler arm for?,

maintaining the idler pulleys in engagement with opposite sides 4of the beltv under sum-

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