US2385445A - Rotor grinder machine - Google Patents

Description

51. ABHAUING.

Sept. 25, 1945.

L ILLMER ROTOR GRINDER MACHINE Filed Nov. 20, 1943 Examine 5 Sheets-Sheet 1 Err-1A.

INVE N TOR:

51. ABRADING.

Examine Sept 1945- l L. lLLMER 2,385,445

ROTOR GRINDER MACHINE Filed NOV. 20, 1943 5 Sheets-Shut 2 o INVENTOR "-rrw 4" 0|. l-mrmuuvu. EAZIHIIIIE Sept. 25,1945. 2,385,445

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Sheet 3 INVENTOR:

51. ABRADING. Examine p 25, 1945- L. ILLMER 2,385,445

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Shea t 4 OI. Abrmullw.

p 1945. L ILLMER 85,

ROTOR GRINDER MACHINE Filed Nov. 20, 1943 5 Sheets-Sheet 5 '1 r///////////. WNW

txammei 51. ABRADING.

Patented Sept. 25, 1945 Examin UNITED STATES PATENT OFFICE 19 Claims.

The present invention broadly relates to the art of surface grinding and polishing equipment, and is more particularly adapted to abrasively treat a comparatively wide band of sheet metal, multiple strips or the like flat stock in successive stages while sheathed about the perimeter of a driven rotor drum as a work piece. My unitary machine is of the dragged work piece type designed to efficiently pregrind and to polish high tensile sheet stock such as annealed or tempered steel plate without requiring any rapidly moving members other than a fast moving work piece which of itself furnishes the necessary cutting velocity for intensive abrasive action.

It is preferred to work with a single power driven rotor of adequate diametrai size that may be housed between laterally spaced frame standards. Such uprights also constitute racks between which to erect a row of tape supply spools and a corresponding row of driven feed reels that positively pull multiple roll tapes through separate cutting zones at a slow rate of linear advance.

Distinctive grades of tape respectively possessing a coarse and fine grit characteristic, may be carried by certain of said supply spools. The width of each individual tape is purposely kept materially narrower than the marginal dimension of the treated plate, the respective cutting zone ends of like grit being overlappingly staggered to constitute a combined zone length that spans the entire plate width. Sectionalized pressure applying shoe units may be provided to floatingly mount such tapes and these units may be collectively backed by header means serving to independently impress such several tapes toward their treated plate under substantially equalized cutting thrust.

The present mode of treatment is in part based upon the teachings set forth in the Illmer and Pallas Patent No. 2,338,644, issued January 4, 1944, in which multiple cutting zones are spacedly distributed to lie in an are about the rotor axis. This earlier embodiment has been improved upon to lower production costs by the addition of perfected control features.

In the pri sent instance, my rotor sheath may be prefabricated to facilitate its rapid application, and vnen installed, may be subjected to tangential tension by compensating means. In addition, provision is made for shiftably guided header means that may be power oscillated about trunnions to selectively bring different grades of grit into alternative grinder zones while my rotor remains operative. Interlockingly clutched feed means actively drags appropriate tape grit through one such alternative cutting zone. The supply spool rack has been arranged for quick replenishment of spent tape to attain a well sustained machine output requiring the minimum labor requirement and shutdown period between grinder runs.

The object of my invention is to devise a compact grinder machine of the indicated character adapted as a unit to handle a single kind of abrasive or multiple abrasives of distinctive grits that may be selectively shifted from inactive into active position for successively applying such several abrasives on a rapid low productive cost basis per square foot of completed sheet output. Embodied herein are also control refinements and improved devices for quickly rough grinding or finishing flat stock while applied to a cylindrical portion of an impelled rotor whereby to promote servicing and satisfy other operative requirements.

Reference is had to the accompanying five sheets of drawings which are illustrative of a preferred exemplification, and in which:

Fig. 1 is an elevational side view of my assembled grinder machine substantially held to scale, and Fig. 1A fragmentally represents a modified detail.

Fig. 2 shows a front end view of said assembly with the rotor depicted cross-sectionally.

Fig. 3 illustrates a sheath compensating device taken along 3--3 of Fig. 2, and Fig. 4 is a transverse view thereof.

Fig. 5 presents a face view of a ratchet sprocket taken along 5-5 of Fig. 2, and Fig. 6 is a crosssection thereof.

Fig. 7 exhibits a rear elevational view of my machine assembly, and Fig. 8 shows in perspective, a preformed plate of semi-cylindrical shape made ready for sheathing my rotor.

Fig. 9 fragmentally details a trunnion shaft with mated cantilevers of which corresponding ends are bridged by similar header beams, and Fig. 10 is taken cross-sectionally along l0l0 of Fig. 9.

Fig. 11 schematically indicates the overlapping edgewise disposition given to my staggered tapes, and Fig. 12 is a side view of a tape backing shoe.

Figs. 13 and 14 respectively show a cross-sectional and a face view of my tape supply spool.

Figs. 15 and 16 correspondingly show similar views for a tape ofltake reel.

Fig. 17 corresponds to Fig. 3 and reveals alternative sheath compensating means.

Referring more seciflcally to Figs. 1 and 2, such grinder assembly comprises a driven rotor that may be subdivided into plural sections lOA, HIB etc. of standardized rim width. These sections may be mounted in tandem upon a common horizontal axle H to build up a prescribed overall width W (see Fig. 11). Said axle may be carried between the bearings 12 and I3 respectively mounted upon separate pedestals such as H that project forwardly from the erected spaced housing standards 15 and IS. The contour of each such hollow frame member may be recessed to provide for a throat that amply clears the rotorfor servicing. The rear frame edges may be disposed vertically as shown and equipped with ailixed top and bottom cross plates I8 and I9 that may be laterally re-enforced in any suitable manner. A depressed frame step 2|] may likewise be platen connected to further provide for a rigid unitary housing structure.

The rotor axle may be driven from a primary motor (not shown) through the main tractor pulley 22 or an equivalent centralized planetary gear reducer. My rotor is preferably held to a diametral size that will impart a pcripheral velocity of several thousand feet per minute to its applied sheath. As detailed in Fig. 1, the rotor rim sections IDA, |B etc. may individually or integrally cast in metal and respectively provided with an endless cored jacket 23 whose cooling fluid may beentered into one drilled axle end through the slip fixture 24 and distributed in parallel by the controlled intake piping 25. The resulting artificially induced cooling is added to the natural rotor radiation into the atmosphere. The circulated fiuid may be carried 011 by the outlet piping 26 through the other axle end as shown. Such flow disposition substantially equalizes the temperature in all sections without tendency to warp the rotor perimeter when operating under intensive rough grinding conditions.

Diametrically opposed perimetric regions of my rotor may be provided with sunken channel like cross grooves or parallel niches 21 and 28 of which the bottom wall may be kept imperforate to allow of incorporating the jacket 23 thereunder (see Fig. 1). In each such niche there may be fixedly installed a pair of spaced guides 29 and 30 of which the first named is shown provided with a leading sheath gripping edge 3|. Slidably interposed between such guides is a keeper bar or the like compensating means 32 of which the shiftable trailing edge 33 may be reversely beveled to its opposed anchored guide edge 3| and have said keeper overlappingly concealed behind the applied sheath 38 in the Fig. 3 manner. Said bar may extend through all of the rotor sections and have its overhanging ends conjointly actuated by a pair of similar levers such as 34 afllxed to a common rock shaft 35. Compression. springs 36 may energetically urge the bar edge 33 toward its opposed guide edge and tend to automatically close the interposed gap marked G.

Fig. 8 discloses a constituent style of semicylindrical plate stock or the like curved sheath component with which it is preferred to segmentally embrace the rotor perimeter. The sheath width W may be kept sufliciently wide to span plural rotor sections but equivalent multiple bands may be substituted in lieu thereof. Where the entire rotor rim is to be overlaid, the curled portion of each such sheath component may be prefabricated by bending roll means from moderately thick sheet stock of standardized overall length having the respective ends radially inturned by power driven die creasing means into a hook-shaped lip 39. The arcuate span between such complementary lips may be accurately held to a predetermined size that will properly fit between the gripping edges 3| and 33 respectively lying in the opposed rotor niches 21 and 28. Such preforming practice readily allows relatively heavy plate stock to be shaped up without unduly delaying active grinder performances. It will be observed that the effort exerted by the spring 36 is wholly directed tangentially of the cylindrical rim and hence does not require the lip region of my applied sheath 38 to be progressively creased or otherwise deformed while being stretched into place.

By means of a motorized socket wrench, the thrust spring 36 may be forcibly compressed through the screw shank 40 see (Fig. 3) and thereby open the gap G with dispatch. By then hooking a sheath lip 39 onto a leading guide edge 3|, the complementary lip of an applied sheath component may be dropped into place. By now unscrewing said shank to release its spring 36, the installed component may be maintained under considerable tangential tension to snugly fit and thereby minimize the air gap between the applied sheath and its rotor perimeter. This aspect assumes importance in that an interposed thick air gap or other cushioning means would constitute the principal hindrance in conducting heat fiow into the underlying water jacket 23. The gap G is preferably kept reasonably narrow so as to be readily bridged without allowing the spanning tape to saggingly enter therein to an inordinate extent.

The aim is to intensively rough grind an applied sheath without allowing its temperature to rise beyond reasonable limits for immediate handling. Said spring actuated keeper bar assembly constitutes self-compensating means that automatically follow up expansion and substantially maintain tangential tension, after the treated sheath has become hot under prolonged abrasion. Such compensation prevents a material enlargement of the initial air gap by sheath slackening or buckling.

As an alternative arrangement, attention is directed to Fig. 17 in which the primed numerals correspond to the similar Fig. 3 element. Such modified compensation is especially suited for an air cooled rotor sheath 38. A non-jacketed rotor rim 98 may be transversely split to leave a slot 28'. Said rim may be cast of metal or made of heavy plate stock such as rolled aluminum having an expansion and a heat conduction coefilcient superior to the treated sheath 38'. Said slotted rim may be interiorly re-enforced by a welded bridge strap 99 of like material. The modified toggle type of keeper bar 32' may by a tongue connection, be tiltably mounted in its slot to hingedly swing outwardly into its dotted position by the aid of a turn buckle I00 that thrusts against a fixed pivot |0|. Such keeper thust is again directed tangentially of the rotor rim without either lip end region of my preshaped sheath 38 having to be further cimped by such thrust.

One sheath lip may engage the gripping edge 33' of a raised keeper and under toggle action be tightly drawn into operativ position by a shortening of the turn buckle. The sheath 38' is thereby subjected to initial tangential tension without need for the springs 36 of Fig. 3. When such installed sheath becomes heated by prolonged abrasive action, it promptly shares a substantial heat portion with its underlying rotor rim and at the same time sets up sufilcient difierential expansion to keep the sheath taut on its run.

A twin sheath component may likewise be applied to complete the other half of the rotor perimeter. If desired, a single sheath of extended length may be substituted for semicylindrical components and be draggingly applied to run in unison with a portion of the rotor rim, particularly where the treated stock is kept relatively thin as in tin or terne plates. Subsequent to the removal of a heavier finished sheath, such ini tially warped sheet may by stretching or counterrolling be restored to its original flat condition.

The forward portion of my rotor is purposely kept accessible for convenient sheath manipulation by an attendant standing upon the front platform where my divers remote switch controls are preferably located. To facilitate rapid sheath replacement by a slow preparatory turning of the rotor, an auxiliary motor-driven gear reduction box 4| may be provided, for having a slow speed output shaft equipped with a sprocket pinion 42 that chain drives the ratcheted axle sprocket 43 (see Fig. 2). As detailed in Figs, 5 and 6, the latter sprocket may include spring retained roller pawls or clutch means 44 through which the rotor may be intermittently turned while applying its sheath thereto. Said pawls are directed to grip the sprocket 43 when the drive pulley 22 remains stationary. However after this pulley becomes operative, the rotating axle is made to overtake the released rollers and leave the reducer 4| standing idle.

The preferred mode of abrading the exposed sheath face will now be defined. Fig. 1 illustrates a suitable layout of my multiple tape supplies which may be stowed upon a series of roll-carrying spools such as 45 that suflice for a full days run. By dismantling the spool side flange 46 (see Figs. 13 and 14), a roll of abrasive tape 41 may be centered upon the hub 48 which may be releasably doweled at 49 to the spool shaft 50. As commercially furnished, roll tape is commonly provided with a comparatively small standardized bore. Spaced guide rods such as 52 may horizontally direct the off-coming tape while held taut by the flange engaging drag clip 53.

As represented in Fig. '7, an erected row of independently demountable spool shafts such as 50A, 50B etc. may respectively be bracketed in arallelism between the housings l5 and I6. Each such shaft preferably carried a plurality of laterally spaced spools 45 that are staggered with respect to the spools carried by a certain other shaft to provide for a small tape lap marked L. The grouped SpoOl disposition is such as to afford an edgewise overlap for my staggered grinder zones of the kind depicted in Fig. 11 and thereby constitute a combined, virtually continuous cutting zone length that extends across the entire sheath width W. One or more of such abrasive zone groups may be spaced in an are about the rotor axis in the manner of the Fig. 1 layout. In order to successively pregrind and finish a common sheath, tapes of different grits may be stowed upon next adjacent spool shafts such as 50A and 503.

The frame standards may be further bridged by complementary trunnion shafts 54 and 54'. Aflixed to the respective end regions of each such trunnion are aligned cantilevers 55 and 56 of which corresponding extremities may be rigidly spanned by a header beam 51 or 58, said opposed beams being dihedrally inclined with respect to the rotor axis. The laterally spaced tape distribution associated with the trunnion 54 is intended to be staggered relative to the tapes backed by the mated beam on the other trunnion 54' (see Fig. 7).

As exemplified in Fig, 10, each beam may be provided with one or more transverse bores or the like apertures such as 59 respectively having a tubular slide 60 mounted therein in a registering backing relation to the corresponding tape that co-operates therewith. A closed end of each slide may be forked for the reception of a pivotally mounted tape backing shoe 6|. Such relatively short shoe segment may slightly overhang its narrow tape 4'! in the Fig. 12 manner, said shoe throughout its length preferably being kept inherently rigid in order that its deflection under operative loading, may not exceed the resulting chip depth G presently to be defined.

Mated idler or tape guide rollers 62 and 63 may respectively be carried along opposite sides of each header beam with their roller end flanges arranged to accurately retain the several tapes in proper registry with corresponding backing shoes. Resilient means such as the compression spring 54 may be installed within each slide 60 to floatingly back the shoe thereof. An abutment plate 65 may arrest such spring thrust when the shoes are shifted into a neutral position designated H in Fig. 10. After said shoes are brought into operative position. such stop means may also prevent tape from unduly entering the sheath gap G of Fig. 3.

By slightly rocking the trunnion shaft 54, the shoes associated with one such header beam may collectively be brought into engagement with the rotor sheath. The degree of backing pressure which the engaged springs 64 respectively exert upon such interposed tapes, may be regulated by the tilt given to a loaded beam. Because of its magnitude, the aggregate spring reaction falling upon a fully loaded beam is likely to set up considerable deflection.

It is emphasized that such multiple narrow tape components when used in combination with individually stiff backing shoes, maintain a substantially even pressure intensity across the whole length of a combined cutting zone irrespective of the accompanying beam deflection. To mak any required minor correction, the initial tension of the spring 64 may be adjustably set by the screw 66.

Corresponding ends of the trunnion shafts 54 and 54' may respectively be provided with an extended arm 68 and with a short rocker arm 61 (see Fig. 1). Such reversed arms may be interconnected by the adjustable tie rod 69 having stub ends. The socketed rod ends may respectively be provided with right hand and left hand threads adapted to co-operate with their stub shanks pivoted to said arms as shown. The upper rod end may be circumscribed by an aiiixed spur gear 10. A remotely controlled reversible motor H resting upon the step 20, may be geared to a depending slow speed outlet shaft having a pinion 12 that meshes with the gear 10.

Upon starting said motor to rock both trunnions in unison, coarse grit of from 20 to 30 mesh may initially be shifted into active engagement with the exposed rotor face. After laying a suitable foundation by such pregrinding, finer grit may be speedily applied to smoothly finish the sheath without rotor removal. The extremity of the extended arm 68 may be provided with a graduated indicator [4 to visualize the prevailing Examiv setting of the applied shoe springs 64 for eitherv coarse or fine grit grinding.

It is preferred to so regulate the feed rate of all tapes that their grit life may become substantially spent in a single pass through each cutting zone. The abraded sheet stock then emerges from a practically fully loaded grit region of the applied tape which tends to impart a virtually burnished finish to the treated sheath face. For a given backing pressure, the resulting rate of grinding is unaffected by grit wear and remains substantially constant as long as slowly fed tape is uniformly supplied.

Should a still brighter polish be sought after applying fine grit, the rotor may be further equipped with beam suspended pairs of supplementary buffer wheels 15 and 16 that may extend across the sheet width W and be shiftably mounted upon a treadle 11 as in Fig. 1A. Such radially pliant buffers may be retarded relative to the sheath velocity by the crossed elastic belt 18.

It now remains to point out the feed mechanism by which mated tape components may be positively drawn into their respective cutting zones at a substantially uniform rate of advance. Such feed roller means may reside in the takeup reel detailed in Figs. 15 and 16. A row of driven reel spindles such as 79A, 793 etc. may be parallelly mounted between my housing standards to co-operate with their corresponding spool shafts in the Fig. 7 manner. Each such spindle may mount spaced multiple reels such as 80. The flanged hub 8| thereof is preferably kept materially larger in diameter than the supply spool 45 in order that the spent reeled tape shall not build up to an excessive depth. The bottom end of each such reeled tape may be aflixed against slip by the clasp toe 82.

All reels on any one such spindle may be keyed to rotate simultaneously. A worm gear 83 may be mounted upon each corresponding end of the several reel spindles. Vertically installed in radially opposed relation to such row of worm gears, are a pair of feed shafts 84 and 85. These parallel shafts may each be equipped with plural worms such as 86 or 8! that respectively engage alternate gears as shown in Fig. 1. The upper end of each feed shaft may be provided with a jaw clutch 88 of which mated jaws the respective movable members may be reversely shifted in unison by the control lever 88.

A vertical double reduction gear box 98 provided with a variable speed motor 8| may, through an interposed slow speed output gear, selectively drive either clutched feed shaft 84 or 85 through one of the twin spur gears such as 92. The control lever 88 may be interlocked by the link 94 to move in unison with the extended lever 68. One end of such link may be provided with a spring retained slide block 95 disposed to yield should a shifted clutch jaw fail to fall into immediate registry prior to starting the remotely controlled tape feed motor 9|.

Since the several reels are gear driven and positively aflixed to their respective tapes, the feed rate of all actively advanced tapes may be kept substantially identical. The slightly accelerated feed rate resulting from accumulation of tape on their re .pective reels, may be compensated by a speed change in the motor 9|. A materially different rotative rate on part of the feed shafts 84 and 85 may be had by the use of unequally sized clutch drive gears such as 92.

As will appear from the Fig. 1 assembly, the several sets of offtake reels and their corresponding supply spools, are respectively arranged to provide for non-interfering tape travel paths designated 41A, 413 etc. that are individually threaded over guide rollers and led toward their associated backing shoes. Upon falling into operative engagement, the jaw clutch 88 of the feed shaft will gear drive both of the reel spindles 19B and 19D in unison. After pregrinding the rotating sheath face with coarse tape, the motor H serves to shift the header beams and thereby bring the fine tape spindles 19A and into service. Finally when all beams are placed into neutral position, the buffers 15 and 16 may be applied.

Certain appended claims have been drawn with the following standpoint as a basis: Corresponding engaged header beams marked 58 in Fig. 1 as respectively mounted upon the mated trunnion shafts 54 and 54 and supplied with tape of like grit, may in association with their shoe components 6|, be considered as constituting primary dual presser agencies, whereas the opposed raised beams marked 51 together with their released shoes, collectively make up companion dual presser agencies. It will be obvious that both such primary and companion agencies need not be combined as described since one such suffices where a dual grit treatment is not required.

The purpose in fully motorizing my more essential controls, is to achieve a saving in labor costs which may otherwise constitute the major item in production expense. As a further refinement, provision has been made to quickly replenish the fully spent tape supplies. Accordingly, I preferably provide for simplified clutch means between each reel spindle and its worm gear 83 as shown. In the present instance, a releasable flange 96 may be keyed to its spindle and be withdrawably doweled at 81 to the gear thereof.

Assuming the several supply spools 45 each initially carry a fresh roll of tape and the tape backing shoes to stand in neutral position, then after such supply has become substantially exhausted, an appropriate spindle flange 96 may be uncoupled to allow of reversely transferring the spent tape back to its original spool. After the reels are stript and the respective tape end regions come into adjacency with a corresponding supply spool, such ends may be severed to permit of bodily dismounting any one of the shafts such as 50 and of installing a freshly supplied substitute shaft. The respective free roll ends of each renewed tape supply may then be stapled to a corresponding severed tape end and drawn onwardly along a threaded tape path beyond its associated shoe 6|. The recharged machine is thus made ready to continue grinding without an extended shut down period.

In order to basically present the characteristic performance of my drag type of grinder machine. its underlying behavior may be more precisely set forth by the following empirical equation deduced from extended research work for floatingly mounted abrasive elements whose grit is substantially spent in one pass through a cutting zone I P" V" g ab out where g=so called mean chip thickness or realizable grit penetration per pass under dry cutting conditions, inches.

P=intensity of applied tape backing pressure, lbs. per sq. in. of grit embedded contact area.

V=linear cutting velocity of a dragged work piece surface, feet per min.

n=fractional exponent lying between A and /3,

with a mean value of about 0.3.

M=abrasive grit for roll tape as measured in terms of its sieve mesh per inch.

TS-mean tensile strength of abraded steel stock, this being approximately proportionate to its degree of superficial hardness, lbs. per sq. in.

It will be observed that the single pass out G is inherently limited in depth by the grit mesh M, also that g does not increase directly with the applied unit jaw pressure P but only with a certain root thereof. The maximum allowable value of P is found to rise with the TS factor but to drop with V, that is to say when working at a fast cutting velocity, the permissible jaw pressure is reduced to obviate tape failure.

Where the diameter of the sheathed rotor such as [A is kept sufficiently large, it presents a virtually fiat contact area or grit embedded cutting zone for which its allowable pressure P may without tape failure, be held at a materially higher intensity than for a treated curvature of much smaller radius.

The cubic inch of abraded metal delivered per minute per inch of tape width, may be determined by the product (2 VAg, wherein A represents the effective cutting zone width as taken in inches. The flat shoe 6| of the instant machine may work with a tangential width of about onehalf inch width which calls for a proportionately fast one pass tape feed in order to maintain the whole zone extent at maximum cutting capacity. The cited delivery product also represents a measure of the power drive requirements.

Intensive coarse grit grinding necessitates the imposition of ample pressure intensity which in turn sets up considerable internal frictional drag or power wastage by heating. As intimated, it is therefore preferred to operate with a relatively fast sheath velocity combined with a moderate pressure in order to attain high cutting efliciency, lowered heat losses and a generally superior output for a given size of grinder machine.

Under dry coarse grit conditions, a cut depth G of about inch may be realized with moderately hard steel. Since this cut is successively removed around the entire sheath length during each revolution, an intrinsically high rate of stock removal may be attained with the present equipment. As a result, individual sheets may be completely treated in a comparatively short time and my associated control devices serve to correspondingly minimize the grinder attendance costs. As a further attribute, my compact vertical machine may be kept reasonably low in first cost. and occupies relatively means together with a shiftably mounted abrasive element possessing a certain grit characteristic and which element is operatively interposed between said backing means and 2. treated side face of said sheet to establish a cutting zone extending crosswise of said sheet, companion presser agency means embodied as a constituent of the same machine and operatively arranged to abrade said face in a manner substantially identical with the first named agency means except for a difference in grit characteristic, and motorized control means for selectively shifting the abrasive element of one such agency means out of its cutting zone and for shifting the other element into active face engagement, the respective cutting zones of such abrasively different elements being disposed in substantial parallelism with each other.

2. In a grinding machine for treating sheet stock and which machine comprises a shiftably guided presser agency supplied with abrasive tape possessing a certain grit characteristic that is operatively interposed between tape backing means and a treated sheet side face to establish a cutting zone therealong, a companion presser agency substantially like the first named agency except for a distinctive grit characteristic and which abrasively distinctive tapes have their respective cutting zones disposed in substantial parallelism .controlled feed means for independently advancing said tapes toward their respective cutting zones, and manipulative control means for selectively shifting one such agency out of its cutting zone and for halting the tape feed means associated therewith.

3. In a abrasive machine for treating sheet stock and which machine comprises dual presser agencies each provided with a plurality of shiftably mounted shoe components distributed tandemwise athwart a treated sheet side face with the lfl shoes of one such agency kept laterally spaced in small floor space for its effective output capacity.

The foregoing rather explicit disclosure will it is believed, make evident to those skilled in this art, the more outstanding commercial advantages afforded by my improvements over the prior grinder art. Since certain aspects of. my controls are likely to find application to purposes other than the treatment of a rotor sheath, I reserve the right to modify the structural features specifically disclosed in my single illustrative embodiment adapted for both coarse or fine grinding, all without departing from the'spirit and scope of my invention heretofore described and more particularly defined in the appended claims.

I claim:

1. In an abrasive machine for treating elongated sheet stock and which machine comprises presser agency means provided with backing a staggered relation to those of the other agency and which several shoes are provided with header means for exerting a substantially equalized backing thrust thereon, an abrasive element possessing a certain grit characteristic interposed between each such shoe component and said side face and wh ch elements when actively engaged afford two series of substantially parallel abrasive regions lying in said face to conjointly establish a virtually uninterrupted cutting zone, companion dual presser agencies substantially similar to the first named agencies except for a difference in grit characteristic and which companion agencies have their conjoint cutting zone disposed in the aforesaid face, and control means retaining the abrasive elements of the first named dual agencies out of cutting engagement with said face while the elements of the companion agencies are actively engaged.

4. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means adapted to have such stock applied to and dragged by a portion of the rotor perimeter and exposing a rotating sheet side face for treatment, a presser agency equipped with shiftably guided backing means that serves an abrasive element interposed between said backing means and the exposed side face to establish a cutting zone extending crosswise of said face and lying in a curved surface centered about the rotor axis, a substantially similar companion presser agency arranged to co-operate with the aforesaid face to provide for an alternative cutting zone lying in substantial parallelism with the first named zone,

and control means for shifting the respective guided backing means in unison to selectively disengage the abrasive element of one such presser agency and bring the element of the other agency into engagement with the cutting zone thereof.

5. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means adapted to have such stock applied to and dragged by a portion of the rotor perimeter and expose a curved rotating sheet side face for treatment, a pair of spaced levers alignedly pivoted to rock in unison and having their respective fulcrums disposed in parallelism with the rotor axis, header beam means spanning corresponding ends of said levers and which beam means mounts a resiliently backed shoe arranged to co-operate with an abrasive element for imposing a regulatable grit thrust thereon, said shoe being guided by said levers from a certain neutral position into operative grit backing engagement with said face, and manipulative means for progressively rocking said levers to impose a gradually increasing thrust upon such engaged shoe.

6. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means adapted to have such stock applied about the rotor perimeter and expose a rotating sheet side face for treatment, a pair of spaced cantilevers alignedly pivoted to rock in unison and having their respective fulcrums disposed in parallelism with the rotor axis, complementary header beam means respectively spanning corresponding ends of said cantilevers and which beam means each mounts a resiliently backed shoe arranged to co-operate with an abrasive element for imposing a regulatable grit thrust thereon, the shoe associated with one such beam means being guided by said cantilevers from a certain neutral position into operative grit backing engagement with said face, means for progressively rocking said cantilevers to impose a gradually increasing thrust upon such engaged shoe, and indicator means registering the extent of such thrust.

7. In a grinder machine for abrading sheet stock, said machine comprising driven rotor means adapted to have such sheet applied to a portion of the rotor perimeter and expose a rotating side face for treatment, a pair of laterally spaced trunnion shafts mounted to rock in parallelism with the rotor axis and respectively provided with shiftably guided shoe means controllably arranged to back an associated abrasive element and which shoe means are alternatively shiftable toward said face, and operatively interconnected arm means serving to rock both trunnion shafts in unison.

8. In a grinder machine for abrading sheet stock, said machine comprising driven rotor means adapted to have such sheet applied to a portion of the rotor perimeter and expose a rotating side face thereof for treatment, mated trunnion shafts respectively mounted in substantial parallelism with the rotor axis, a pair of aligned cantilevers spacedly installed upon each such shaft, complementary header beam means respectively spanning corresponding end regions of each pair of cantilevers and which shiftably guided beam means are each equipped with backing shoe means that respectively co-operate with an associated abrasive element, actuated rocker arm means for each such trunnion shaft, and adjustable tie rod means interconnecting the respective rocker arms and which tie rod means when adjustably altered in length brings one such abrasive element of each mated shaft into operative engagement with said face.

9. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means adapted to have such sheet applied to and dragged by a portion of the rotor perimeter and expose a rotating side face for treatment, a pair of spaced lever means alignedly fulcrumed to rock in unison and having their respective fulcrums disposed in substantial parallelism with the rotor axis, header beam means shiftably guided by said lever means and which beam means is provided with multiple transverse apertures respectively arranged to mount a slidable member of which one end region carries backing shoe means that co-operates with an associated abrasive element located in adjacency to said face, resilient thrust means for each such slide member, said means being arranged to collectively react upon said beam means and impose a substantially equalized grit backing thrust upon the several shoe means irrespective of the resulting beam deflection, and controlled rocking means for said lever means whereby to selectively shift said beam means and associated shoe toward or away from said face.

10. In an abrasive machine for treating sheet stock, said machine comprising laterally spaced housing standards respectively equipped with forwardly disposed bearing means, driven rotor means installed between said bearing means and adapted to have such stock sheathingly serviced about the rotor perimeter to expose a sheet side face for treatment, a spool shaft spanning a rearward portion of said standards in substantial parallelism with the rotor axis to leave the forward portion of the rotor perimeter unobstructed for stock servicing and which spool shaft is arranged to carry a series of tape supply spools thereon, spindle means alignedly mounting a corresponding series of reels thereon, shiftably mounted header beam means arranged to carry a corresponding series of backing shoes that respectively lie adjacent the exposed sheet face, each such tape supply being separately threaded along an advancing travel path interposed between the corresponding shoe thereof and said face and whereupon the several tapes are respectively affixed to the hub of a corresponding reel, and controllable drive means rotating the several reels in unison.

11. In an abrasive machine for treating sheet stock, said machine comprising laterally spaced housing standards respectively equipped with bearing means, driven rotormeans installed between said bearing means and adapted to have such stock sheathingly applied to a portion of the rotor perimeter to expose a sheet side face for treatment, complementary cantilever means alignedly fulcrumed to rock in unison, a pair of header beam means respectively bridging corresponding end regions of said cantilever means and shiftably guided thereby, said beam means being each provided with a tape backing shoe disposed in adjacency to said side face, a pair of spool-carrying shafts that span said standards in substantial parallelism with the rotor axis and respectively provide for an independent supply of roll tape possessing distinctive grit characteristics and which abrasively different tapes are separately advanced toward the shoe corresponding to one such shaft, a pair of independently actuated spindle means respectively mounting a tape feed reel thereon that serves one kind of such tape, and interlocked control means for selectively shifting one of said shoes toward said face and for responsively feeding the tape leading thereto.

12. In an abrasive machine for superficially treating a work piece and which machine comprises shiftably guided header beam means that carries a tape backing shoe disposed in adjacency with the treated work piece surface, a bodily demountable spool carrying a roll of abrasive tape thereon, a tape of! take reel mounted in substantial axial parallelism with the spool, said tape being advanced along a travel path leading to the reel and having a medial length region operatively interposed between the shoe and said surface, and clutched drive means positively rotating said reel in one direction for initially transferring roll tape onto said reel, said clutched drive means when released allowing the tape to be reversely transferred back to the demountable spool.

13. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means adapted to have such stock applied to the rotor perimeter to expose a rotating sheet side face for treatment, controlled main tractor means for intermittently driving the rotor means at comparatively high speed, shiftably guided beam means that carries an abrasive element disposed to grind said face and which element is shiftable into a neutral position upon completion of such grinding, and auxiliary speed reducing means provided with a clutchable output shaft through which during intermittency of the main tractor means to slowly drive the rotor.

14. In an abrasive machine comprising driven rotor means whose perimeter is equipped with an immovable gripping edge and a cooperating movable gripping edge respectively disposed in substantial parallelism with the rotor axis, said perimeter being adapted to have a sheet of stock applied thereto in sheathlike fashion to present an exteriorly exposed face for abrasive treatment, the respective sheet ends being radially inturned to constitute complementary lips respectively hooked into engagement with said gripping edges, and automatic compensating means including shiftable mounted keeper bar means of which an edge constitutes the aforesaid movable gripping edge, and thrust means urging such bar edge in a direction tangentially of the rotor perimeter and serving to maintain a substantially unslackened tension along the applied sheet face when subjected to abrasive heating.

15. In an abrasive machine for treating sheet stock, said machine comprising driven rotor means having a transversely niched perimeter, actuated keeper means shiftably disposed in such rotor niche and equipped with a lip gripping edge, said perimeter being adapted to have a sheet of stock embracingly applied thereto in overlapping relation to the keeper means and present an exteriorly exposed face for abrasive treatment, the respective sheet ends being radially inturned to constitute complementary lips of which one such lip is gripped by the relatively shiftable keeper edge, a mated anchored gripping edge for said perimeter serving to fixedly retain the other lip, thrust means actuating such keeper edge in a direction tangential to the rotor perimeter to impose a corresponding directed txamme tension along the applied sheet, and a abrasive element placed into operative engagement with the exposed face of such tensioned rotating sheet.

16. In an abrasive machine comprising driven rotor means provided with a transversely slotted perimeter and which perimeter is adapted to have a sheet of stock embracingly applied thereto possessing a coeflicient of expansion lower than that of the perimeter, said sheet presenting an exteriorly exposed face for abrasive treatment and the respective ends thereof being radially inturned to constitute complementary lips, keeper means mounted in the rotor slot and including a swingable toggle edge arranged to grip one of the aforesaid lips and subject the applied sheet to initial tension, a mated grippin edge for the rotor serving to retain the other lip, and an abrasive element operating on said face and which sheet upon becoming heated continues by differential expansion to keep said lips engaged with their respective gripping edges.

1'7. In an abrasive machine for treating sheet stock, said machine comprising a jacketed rotor mounted upon a driven axle, the rotor Jacket being inducedly cooled by circulated fluid and the rotor perimeter being provided with a pair of diametrically opposed slots respectively having keeper means installed therein, said perimeter being adapted to have a pair of prefabricated semi-cylindrical sheet components sheathingly applied thereto to segmentally complete a virtually endless rotating face that circumscribes said axle, the respective ends of each such prefabricated sheet component being radially inturned to constitute complementary lips that are respectively hooked into said opposed slots, keeper means overlapped by one such sheet component and serving to retain a lip thereof, and an abrasive element placed into operative engagement with said rotating face.

18. In an abrading machine for treating sheet stock, said machine comprising driven rotor means adapted to have such stock applied to the rotor perimeter to prepare an exposed sheet side face for treatment, shiftably guided header beam means provided with backing shoe means arranged to be shifted toward or away from said face, a guide roller carried along each side of said beam means in registry with the shoe means, and a supply of abrasive tape of which a length region is alignedly threaded over both such rollers and interposed between the shoe means and said face.

19. In a grinder machine for superficially treating sheet stock, said machine comprising impelled rotor means adapted to have such stock applied to a portion of said means and expose a sheet side face for treatment, shiftably guided header means provided with a slidable member of which one end region carries a backing shoe and which shoe is arranged to be bodily moved toward or away from said face in unison with a shift of the header means, resilient means thrusting against said header means and serving to urge the backing shoe toward the treated face, an abrasive element interposed between said shoe and face, and stop means limiting the shoe travel toward said face.

LOUIS ILLMER.

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