US2349964A - Grinding and polishing machine - Google Patents

Description

May 30, 1944. L. HERCIK GRINDING AND POLISHING MACHINE Filed June 20. 1941 4 Sheets-Sheet 1 May'30, 1944; 1.. L. HERCIK 2,349,964-

GRINDING AND POLISHING MACHINE Filed June 20,1941 4 sheets-sheet 2- I as a v '57 96 95 a2 60 L40 L. [RC/A" I 57% 96!) irramvn' May 30, 1944.

.| 1.. HERCIK GRINDING AND POLISHING MACHINE 4 Sheets-Sheet 3 Filed Jung 20. 1941 v a W m a m mm 2 ME. M a 0 Wu H v M N 9/ MM W, w

r w 2 I Patented May 30, 1944 UNITED STATES PATENT OFFICE GRINDING AND POLISHING MACHINE Lad L. Hercik, Lakewood, Ohio, assignor to The Hill Acme Company, Cleveland, Ohio, a corporation of Ohio.

ApplicationJune 20, 1941, Serial No. 398,886

23 Claims.

This invention relates to abrading. apparatus of that type. in which the abrading element comprises a, flexible rapidly travelling, abrasive belt coated on one, face with suitable abrading material. In machines of this type the. belt is usually mounted on a plurality of rolls or pulleys one of the rolls being the driving roll causing the belt to travel and another of .therolls being the contag; or pressure roll serving-to engage thev rapidly travelling belt with the work;to be treated in the machine. this type isusually moved past the contact roll: on a suitable work support substantially juxta posed to the contact roll, suitable means being provided for applying'pressure between the abrasive belt and the work;

While the herein disclosed invention. is adapted for use in many types of grinding, surfacing and polishing machines and while it may also be adapted for producing or treatingsurfaces on many types of material, this invention is particu-.

larly well adapted for use in machines intended for removing scalefrom or for abrading or grinding or polishing or otherwise treating; surfaces on relatively thin flexible sheets or stripsof material.

This work, in machines of- This invention is accordingly illustrated and described in an embodiment ina machine.

the plurality of necessarily high speed pulleys,

shafts, and other rapidly rotating elements supported on the housing of the machine, partly to the irregularities rapidly developed in the sur-- face of the abrading belt by the severe treatment to which the belt is exposed in the machinery at present developed, and partly by the flapping of the relatively long unsupported portions of the rapidly moving non-homogeneous abrasive belt.

It is well known that the best grinding results in machines of-this type are obtained by the useof a contact or pressure roll of relatively small diameter for holding the belt in engagement with the travelling sheetto. be finished. Due to the fact that, in previously known machines, the

two strands of the abrading belt have generally been either approximately parallel or. have been inclined to each other at an acute angle, this.

small contact roll has produced asevere bend in the, belt at the contact roll, tending to elongate the. outer periphery of the belt and to cracklthe abrading surface and. to break the bond between the abrading material and the'belt, thus causing the abrasive material to loosen or flake off or form objectionable projecting ridges. -As a resultof the necessarily high peripheralspeed of the belt, approaching velocities of 4000 feet per j minute, there is a tendency of the belt to spring away from the contact roll andhence, in pre:

viously known machines of this type, considerable tension has been applied to this belt to insure a snug and accurate engagement of the belt with the face of the contact roll thus subjecting the belt to severe strains. As is also known, the driving roll usually is not made ma- 1 terially larger than the contact roll and a heavy strain or tension must be applied to the belt to prevent the slipping of the belt on the drive roll and to prevent the belt wearing, belt heating, belt jerking, and accompanying belt deterioration and machine vibration which results from such slipping. In order to provide ample resilience in the belt, a relatively long belt has heretofore been provided which was mounted upon terminal pulleys spaced roportionately far apart. This arrangement has resulted in relatively long lengths of unsupported belt which have tended to flap or whip thus introducing additional vibration into the machine. All of the above circumstances contribute to the introduction of irregularities in the appearance of the finish formed on the surface of 'the sheets.

One of the general objects of this invention, therefor, is to provide apparatus of this class which will produce an even, uniform and smooth finish upon strips or sheets and, the like, which finish will be free from irregularities, blemishes or defects resulting from the imperfect functioning of the apparatus or abrading belt.

Another object of this invention is to. produce a machine of this type in which the number of rapidly rotating parts are reduced to an absolute minimum and which Will accordingly be free from the cumulative chatter producing vibrations resulting from a plurality of rapidly rotating parts.

A further object is to. produce an arrangement of abrasive belt pulleys in a machine of this class which will eliminate the imposition of severe and destructive bending strains on the belt a grinding machine of this type in which the j abrading 'belt is supported exclusively by one driving pulley and one driven pulley or roll and in which the unsupported lineal length of the strands of belt between the pulley peripheriesis reduced to such a minimum that substantially no perceptible flapping or whipping occurs. 7

A further object is to produce a machine of which actuates mechanism for guiding the abrasive belt.

Fig. 4 is a top plan view of a control device illustrated in Fig. 3.

Fig. 5 is a front elevation of the device shown in Fig. 3, taken from the plane indicated by line 5, 5 in said figure looking in the direction of the arrows. r v

Fig. 6 is a front elevation of this improved machine shown, this view being partly in axial section, taken on the planes indicated by line 6, 6 V in Figures 1 and 8 and by line 6, 6 in Fig. 14.

Figfll is an enlarged view of a portion of Fig. 6 illustrating the mounting of the head shaft in the housing of the machine.

Fig.8 is a transverse section thru the machine taken on the plane indicated by the line 8, 8 in Fig. '6 looking i'n'the direction indicated by the this type in which a relatively large proportion of the length of the abrasive .belt is continuously being cooled by, engagement with the periphery of one of the pulleys onjwhich thebeltis mounted.

A. further objectis to produce apparatus of this type .in which the-pulleys are so constructed and mounted that a minimum of belt guiding and/or centering correction is required after. the belt has once been properly centered.

A further object of this invention is the pro,- vision of a simplified mechanism for controlling the g liding and/or centering ofan abrading belt travelling over a pair ofspaced pulley without the use ofan auxiliary guiding or control roll or pulley.-

A-further and more specific object of this invention is the provision of an improved mounting for the head or driving pulley for an abrasive belt in which this pulley is tiltably' mounted for the purpose of guiding or controlling the path of the belt, the mounting being adapted to be readley on, the shaft and to facilitate the mounting of the pulley on the shaft or the demounting of the pulley from the shaft.

Afurther understanding of the construction and operation and of-the manner in which the novel features of this invention effect the above and further objects, will become apparent from the following detail description and the annexed drawingswhich set forth certain means embodying this invention, such disclosed means constituting,.however, but one of the forms in which the principle of. this invention may be applied.

Referring to the annexed drawings:

Fig. 1 is a side elevation of a grinding and polishing machine embodying this invention, this disclosed machine being shown in an adaptation for grinding and/or polishing continuous metallic sheet strips, this view of the machine being taken from the operators'side of the machine and being partly broken'away to show certain interior constructions.

Fig. 2 is a diagrammatic view illustrating, detached from the machine, certain elements of the mechanism for controlling the path of travel of the abrasive belt and including a wiring diagram and piping diagram disclosing the cooperative relation between the elements.

Fig. '3 is an enlarged view of a portion of Fig. 1 illustrating a certain air jet control device arrows and showing the power drive for the machine.

Fig. 9 is a fragmentaryenlarged elevation of certain mechanism' forangularly tilting the head shaft of the machine, this view being taken from the plane indicated by line 9, 9 in Fig. 6 looking in the direction of the arrows and showing the parts-as they appear as viewed from the far side of the machine.

Fig. 10 is a' fragmentry top plan View of the parts illustrated in Fig. 9.

Fig. 11 is a transverse sectional view thru a portion of the mechanism illustrated in Fig. 9, this view being taken on the I l l l in said figure.

Fig. l2'is a similar transverse sectional view of the mechanism illustrated in Fi 9, this view being taken on the plane indicated by line I2, 12 in said figure. i

Fig. 13 isa fragmentary vertical longitudinal sectional view of the mechanism illustrated in Figures 9 and 10, this view being taken on the plane indicated by line I3, 13 in Fig. 10.

Fig. 14 is a plan sectional view taken thru the aixs' of the head shaft on the plane indicated by line [4, M in Figures 6 and 8.

Fig. 15 is a fragmentary sectional view thru the hub and'head shaft of the head pulley, this view being an enlarged View of a portion of Fig ures 6 and 14.

General features of machine The main portions of this improved grinding and polishing machine may be indicated briefly in general terms as follows:

The base supporting the operating mechanism of the machine is indicated at I. On this base is mounted the work supporting mechanism which includes a vertically and horizontally adjustable billy roll 4. Also mounted on the base i is a column 22 upon which is mounted a head frame or housing 25, this housing being vertically adjustable on the column by means of a head frame adjusting mechanism including a screw 36 and associated power driven mechanism. Rotatably mounted in suitable bearings 42 and 46 in the head frame is a head shaft 50 upon one end of which is mounted a power pulley and upon plane indicated by line ing 42 serves as a fixed pivot about which tne head shaft may be tilted and the other bearing 46 is shi'ftably mounted so as to providea means for tilting the head shaft and the head pulley, this provision being made for the purpose of correctively guiding the abrasive belt 9|] in the desired path of travel. Suitable mechanism for shifting the bearing 46 and thus tilting the head shaft is provided in the fluid cylinder H I actuated by a valve I32 and a suitable device for controlling the valve is provided by the air jet control unit indicated in its entirety at I44, which unit controls the valve and cylinder responsive to lateral deviations in the path of the abrasive belt. Brake mechanism including a brake drum I62 and brake shoes I65 is provided for rapidly stopping the rotation of the head pulley and abrasive belt.

The construction of the above enumerated features will now be described in detail. For purpose of reference in the following description, the operators side of this machine, that is the side on which the head pulley is mounted, is designated as the near side, and the side on which the power pulley i mounted is designated as the far side of the machine. Also for convenience of reference, the right end of the machine as viewed in Figures. 1, 8 and 14 is designated as the "front of the machine, and the left side of. the machine as viewed in these figures is designated as the rear of the machine.

Work supporting mechanism Referring first to Figures 1, 6, s and 1415f the drawings, the base of the machine is indicated 9 at I this base being of suitable proportions to support the working parts of the machine and being constructed of any suitable material and in any desired manner as by welding or casting. Upon this base are mounted ,a pair of stands 2, 2 upon which are mounted. bearings 3,. 3 these bearings in turn rotatably supporting. a work support in the form of a billy roll 4' of suitable diameter and width to accommodate. the widest sheet for which the machine is designed. The billy roll 4 is adapted to be adjusted horizontally in the direction of travel of the work, that is, to the left or to the right as viewed in Fig. 1. This longitudinal adjustment is made possible by slotting the openings in the flanges of the bottom I of the stands 2 by means of which these stands are bolted to the base. as will be readily understood from the. indication at .5, 5 in Fig- 1. .Eachof the stands 2 may be adjusted individually in order that the axis of the billy r011 may be posi- I tioned in parallel relation to a certain contact pulley 89 hereinafter to be described.

The billy roll 4 is also mounted for vertical movement toward'and from the contact roll 89 and fo this purpose the billy roll bearings 3 are each provided with a base 6 which is slidably mounted in openings 1 formed in the upper portion of the stands 2 as best appears in Figures 1, 6 and 14. The bases 6 are each formed with centrally disposed bosses in which are mounted the upper ends of piston rods 8. rods are each mounted for vertical reciprocation preferably by means of fluid actuated pistons 9 mounted in cylinders Ill. The pistons 9 are simultaneously actuated by means of suitable valve devices of any approved design simultaneously supplying and releasing fluid under pressure to and from inlets and outlets in the cylinders l0.

As clearly appears from Figures 1 and 6, the

These piston.

to abut the lower end of vertically adjustablebushings l2, mounted in housings l3 centrally disposed within the stands 2. of the collars H with the-lower end of the bushings I2 limits the upward movement of the piston rods 8 and thus fixes the upper position of the bearings -3 and hence the billy roll 4.

It Will be evident that the upper position of the billy roll must be adjustable to accommodate various thicknesses of the work, various diameters of the contact roll 89, etc. For this purpose the bushings l2 are made vertically adjustable in order that collars II on the piston rod 8 may engage the bushings at different vertical positions thereby to stop the bearing 3 and billy roll 4 in the desired upper position. Forpurposes of adjustment, the bushings are provided at their lower ends with threads l4 engaging similar threads formed in the housings l3. At their upper ends the bushings are formed with spiral teeth l5 adapted to be engaged by worms It is also essential that an independent vertical adjustment may be provided for each bearing 3'in order that the axis of the billy roll 4 may be disposed accurately parallel with the contact roll 89. In order to permit this independent vertical adjustment a coupling l9 (Fig. 6) is provided in the Worm shaft I 1 which, when disconnected, will permit the individual adjustment of each of the bushings S2 in order that the proper alignment of the axis of the billy roll may be obtained.

A strip or sheet of material to be finished in this machine is indicated at .W and rides upon the upper surface of the billy roll 4 as clearly appears in Figures 1 and 6. This strip W is usually continuous and may be of any desiredwidth within the capacity of the machine and may consist of steel, stainless steel. Monel metal, "bronze, zinc. or other metallic or non-metallic materials which are to be ground, polished, satin finished, buffed or otherwise treated in this machine. It will appear that the strip W is deflected upwardly slightly about the billy roll and suitable auxiliary rolls may be provided for:

grinding en agement of the strip W with the abrasive belt all mounted on the contact pulley 89.

The devices for feeding and tensioning the strip are also well known and. as they form no part of this invention. are not shown. It is to be understood however. that the strip feedin devices are presumed to be manually reversible under.

the control of the operator.

Column andhcad frame support Supported on a pad 2! formed on the'base I is The engagement a preferably hollow irectangular column 22 as to-seat upon thefaces and sides of'the ways 23.

Guideor clamp bars 21, Fig.g1 l, are provided to hold the housing in sliding engagement with the ways: Suitable 'gibs-may be provided to adjust the. tightness oft-he sliding engagement of the housing on the columnways, as will be undert od '..V

. The upper end. o-fthe head frame or housing 25 is formed with a hollowgenerally semi-cylindrical portion 26 whose-axis is disposed horizontally, that is,- transversely of 'the ways 23 of the column. .Forming. acontinuation of the portion 28 and extending laterally from the housing'25 toward the near or operators side of the machine-is a preferably tapered hollow portion 29. This portion 29 extendsfor a considerable distance laterally of the ways 29 and column 22', as best appears in Figures 6 and 14. The portion 29 is formed at its outer end with a recess 36:adaptedto receive a bearing 42, to be hereinafter described. Adjacent the far side of the portion 28*thehousing isformed with seat 3| upon'which is mounteda bracket 32-which in turn supports a bearing 46 by means of mechanism to be described.

-:Formed adjacent the lower edge of the head frame 25 is an outwardly projecting lip 33 which supports a vertical-plate 34 secured to the face of the frame 25 and serving as a base plate for the motor 8i.

Head, flame; adjusting mechanism Fixedly mounted on the rear face of the housing is a nut 35 engaged by a vertical screw 36 (Fig. 8). The lower end of this screw is sup ported in bearings 31 preferably mounted in the base of the column 22. Adjacent the lower end of this screw is mounted a worm gear 38 which is in turn driven by means of a suitably mounted worm 39. The worm 39 in turn is driven thru a pair of spur gears 40 by means of a motor 4|. It will appear that the rotation of the screw 36 will advance the head frame upwardly or downwardly depending upon the direction of rotation.

Head shaft mounting anti-friction rollers 48 and an inner rac e 49,

Mounted in the inner races and 49 of the bearings 42 and 46 is amain or head shaft indicated in its entirety at 50.

The outer race 43 of the bearing 42 is clamped between a tongue formed on a cap 5i and a shoulder formed at the inner end of the recess 30, and is thus axially fixed with respect to the housing 25. The inner race 45 of the bearing 42 is fixed to the shaft between a shoulder 52 formed on the shaft and a nut 53 having threada to the housing 25.

The inner race 49 of the bearing 46 is fixed to the shaft 59 between a shoulder 54 formed on the shaft and a nut 55 having threaded engagement with the shaft, as will appear from an inspection i of the right end of Fig. '7. The outer race 41 of the bearing 46, however; is axially slidably mounted in a cylindrical bore 56' formed in a bearing block 51 supported for horizontal shifting in the bracket 32 and as will appear, space is provided to permit such relative axial shifting. I

The bearings 42 and 46 are each preferably of the self alining type which permit the limited angular tilt of the shaft with respect to the outer race and the bearing housing, this pro- 7 vision being. made for a purpose to be hereinafter pointed out. i

Suitable enclosures and protective seals are preferably associated withthe bearings 42 and 46 all as clearly shown on the drawings.

Power pulley on head shaft At the far or right side, as viewed in Figures 6 and 7, the shaft is formed with a'portion 59- extending outwardly toward the far side beyond the bearing 46 upon which a head shaft power pulley 66 is mounted, this pulley being fixed against rotation on the shaft by means of a key 6| and formed with a rim 62 to receive driving belts, as will bedescribed.

Head pulley and mounting on' head shaft Extending outwardly toward the near side of Y the machine from thebearing 42 and extendingwhich hub is mounted on the shaft portion in. an.-

improved manner to be later described.

The head pulley 64 comprises a plurality of webs indicated at 66, '61 and 68 supporting a rim or shell 69, as best appears. from Figures 6 and The webs 66 and 61 are positioned in radial planes adjacent the outer and inner ends of the hub and the web 68. is principally conical and flares outwardly from the web 61 adjacent the hub toward the rim 69 to which it is connected.

It is to be noted .that the rim 69 is formed with a substantially straight face and. is considerably wider than the length of the hub and that the rim is substantially alined with the outer end of the hub at the near side of the machine and thatthe rim projects well beyond the inner end of the hub and overhangs not only the bearing 42 but also the section 2.9 of the housing 25 and, as will further appear from the. drawings,

the rim 69 is symmetrically disposed about the center of the bearing 42.

The bearing 42 may accordingly be said to be disposed within the confines of the pulley 64 and is in fact preferably disposed substantially centrally of the face of this pulley.

It will be evident that the head pulley 64 being of relatively large diameter and wide face is necv essarily of considerable weight and' difiicult to handle particularly in assembling upon and re'- movalfrom the shaft end 63 upon which it is 6 .mounted. It is also to be noted that centering of the head pulley on the shaft 50 and its axial alinement with the shaft must be perfect in order that the head pulley may run absolutely true and perfectly balanced, not only in the original installations but also in the event of a re-mounting or replacement of the pulley on the shaft. It

7 is also evident that an extremely tight fit between the bore of the pulley and the shaft resultingin the adhering of the pulley to the shaftis seriously objectionable not only because of the difficulty of removing the pulley but also because of the danger of springing or distorting the shaft in assembling the pulley on the shaft or demounting the pulley from the shaft.

In order to facilitate the mounting. and demounting of the relatively heavy head pulley 64 with respect to the shaft, an improved arrangement of parts is provided, which is best .shown in Fig. 15. Referring to this figure, the outwardly projecting portion 63 of the head shaft 50 is formed outwardly beyond the bearing .and preferably adjacent the sealing cap 5.! on the head frame with an outwardly converging conical portion 10 extending outwardly for about one third of thelength of the hub 65 of the head pulley 64. Beyond the end of the conical portion 70 the shaft is formed with a cylindrical portion ll extending outwardly to a point nearly flush with the outer end of the hub 65. Outwardly be yond the cylindrical portion 7|, the shaft is formed with a threaded extension. 12.

The bore of the hub 65 is formed atits, inner end with an inwardly diverging conical surface 13 preferably accurately conforming to the surface on the conical portion 1a of the shaft. Outwhich in practice need not necessarily be more 1 than a few thousandths of an inch.

Mounteduponthe threaded extension 12 is a collar or nut ll having a threaded bore engaging the extension 12 and formed with ,an inwardly converging conical portion 18 accurately conforming to the outwardly diverging conical surface 16 in the hubof the pulley. The .collar or nut H is additionally formed with areoess on its inner face, this recess being formed with a cylindrical surface 19 whose inner diameter is a relatively tight but rotatable fit on the outer diameter of the cylindrical section II of the shaft, which serves to accurately center the nut 1'! on the shaft 50. The nut is provided with a suitable slot for turning. I I

A key 80 is preferably provided engaging suitable keyways in the shaft and pulley hub to serve as a means for rotatably 'fixing the pulley to the shaft.

In assembling the pulley64 on the shaft it will be apparent that-the enlarged end of the outwardly diverging conical opening 13 in the hub 65 will readily pilot the pulley 64 on :the shaft 50, whereupon the pulley is moved inwardly 'until the conical surface 13 of the hub is seated on,

the conical portion 1-0 of the shaft. The nut 11 is then screwed on the threaded extension '12 of the shaft, the nut beingaccurately'axially centralizedand alined with the shaft by the engagement of the cylindrical surface '19 with the cytension .ley hub. The outer end of the pulley is then free of a crane or .other convenient facility :motor 81 this motor any desired manner adapted to adjust the .84 formed with .a plurality .of grooves.

lindrical portion -'H of the shaft until its conical surface 18 engages the conical recess 16 in the hub.- A further advancing of the nut will simultaneously force the inner end of the pulley hub into a firm seating position on the conical portion Ill of the shaft and will accuratelycentra'lize and axially aline the outer end of the pulley with the shaft, thus insuring the rigid coaxial mounting of the pulley on the shaft.

When the pulley is to be demounted from the shaft, the nut 11 is backed off the threaded ex- 12 to release the thrust against the pulto tilt downwardly toward the shaft :to the extent of the limited clearance between the cylindrical bore T5 of the pulley hub and the cylindrical portion H of the shaft. If the pulley is so firmly seated on the conical portion III that it will not readily free itself, a slight tilting stress applied to [the rim of the pulley aided, if necessary, bya slow rotation of the shaft release of the pulley from the conical portion 13 whereupon the pulley may be removed by the use It will be evident that the above construction readily permits the assembly and demounting of the pulley without any scoring or distorting of the mating parts and that the pulley may be demounted and reassembled frequently without affecting the accuracy of the mating parts and that a damaged or worn pulley may be replaced by .a new pulley and that an accurate coaxial almement of the pulley with the shaft is assured at each assembly.

Drive for head pulley Mounted on the vertical plate 34. is .an electric being secured to the plate "which have slotted engageas shown at 82 in Figures screws 83 are mounted in in the plate '34 and are position of the .motor verto the plate '34 and hous- Mounted, on the motor ishaftv is .a pulley Mounted in the grooves 84 andonthe rim .62 of the "power 34 by means of bolts ment with the plate 6 and 8. Adjusting tically with reference ing 25.

pulley '60 are a plurality of V belts 85... It. will appear that by this arrangement the rotationof the motor will be effectively transmitted to the head shaft 50 and pulley .64 without vibration. Asxwill be understood, the proper tension may be imposed on the V belts .85 by suitable vertical adjustment of the motor :by means :of the adjustingscrews 83.

Contact pulley and supports accordingly fixedly mounted withreference to the base I and is substantially parallel to the head pulley .and is below and slightly forwardly positionedxwith reference .tozthe axis of the head pulley 54. It. is to be noted, howeventhat the contact ipulley isnot positioned forwardly beyond the periphery of the head pulley, that is, the contact pulley is located between parallel vertical planes passing thru the axis of xtheheadppulley and tangent to the periphery of the. head ,pulley respectively, and as will .also be evident, the

will quicklyeffec-t the upper periphery of the contact pulley is substantially horizontally alined with the lower periphery of the head pulley, this arrangement just pointed out producing a construction of the maximum compactness.

The axis of this contact roll as will appear from Figures 1 and 6, is spaced from and is positioned above and substantially parallel to the billy roll 4 in the normal position of that roll..

This contact pulley may be made of any suitable solid or laminated material but I have found that contact pulleys made of rubber, synthetic rubber or similar resilient materials ar most efficient in service.

Y v Abrasive belt and mounting A flexible endless abrasive belt 90 is mounted on the head pulley B4 and contact pulley 89,

this belt consisting ofa paper or fabric base or bacl ing material coated on the outer face with flabrading or polishing material suitable for producing the type of finish desired-on the work W.

, The relation between the head and contactqpulley and their relation to the abrasive belt are {considered essentially novel features of this in- ,vention and their relation may be pointed out as than I one sixth of follows: ,As will best appear from reference to Fig. 1, the diameter of the contact pulley 89 is less the diameter of the head pulthat the best results are obley 64 and I find tained with a diameter ratio for these pulleys of substantially one to eight. As will also be clear,

the head pulley and the contact pulley are spaced extremely close together, so close togetherin fact that the axes of the head and --.-contact pulley are spaced from each other a. dis- ,tance less than the diameter of the head pulley. lyhave further found it desirable to space the periphery of the contactpulley clos to the ad- ;iacent portion of the periphery of the head pulley and for this reason I prefer to space the peripheries of the head and contact pulleys apart a distance substantially equal to or less than the -length of the periphery of tion resulting from flapping or whipping and it will appear that the unsupported length of each of the strands 'does not exceed '1 times the the contact pulley.

: Referenceto Fig. 1 will also disclose the fact that the included angle a between the unsupp'orted strands-90a, 90a approximates 90 and is in fact substantially greater than 80. 7

"Reference to Fig. 1 will also disclose the as that the abrasive belt 90 engages an extremely large portion of the periphery of the head pulley, "the angle of contact being indicated at A andbeting actually in excess of 260. This extensive area of contact between the abrasive belt andthe ahead pulley insures an absence of slipping between the driving head pulley and the belt even when the tension on the abrasive belt is relatively low in intensity.

It-is further to be noted that the abrasive belt becomes severely heated as a result of the abrad- 'ing action between the belt andthe work, thus tending to deteriorate .the belt. This heat is usually intended to be carried away by relatively long lengths of unsupported strands of the belt which are in contact with air. While, these long, unsupported strands have certain disadvantages pointed out, it is also well known that air is a poor conductor of heat, and I have found that the long are of contact of the belt with the head pulley makes possible a substantially complete abstracting of the heat from the belt due to the relatively high heat conductivity of the metal rim of the pulley, this rim being cooled by the air flowing centrifugally outwardly against the inner face of the rim. As will appear, well over 50%, 70% in the embodiment shown, of the total lineal length of the belt engages the periphery of the driving pulley.

It will appear that a proper tension may readily be applied to this belt by suitably vertically moving the housing 25 which in turn supports the head shaft 50 and head pulley 64, whereby the center to center distance between the head pulley 64 and relatively stationary contact pulley 89 may be varied.

This abrasive belt is preferably driven in the direction indicated in the drawings by arrows. As is well known, it is extremely diflicult to maintain a web travelling in a fixed path when the web is travelling on straight or substantially straight pulleys unless the path of the web is controlled by suitable devices. This is particularly true in the case of abrasive belts in which difierences of strength, thickness, pliabality and other differences may initially be incorporated in the belt or in which such differences may progressively develop as the belt is being used due to changes in thickness or character of the abrading coating -or backing. For this reason it becomes necessary in machines of the character described in this application to provid means for returning the belt to the desired path when it deviates from this path. Many and varying types of devices have been developed for controlling the path of such travelling webs, most of which devices include the provision of an auxiliary roll which is suitably manipulatedto correctively guide the web, this roll being actuated by some type of a control device which is actuated responsive to deviations in the path of the travelling web.

The herein described embodiment discloses an improved method of guiding the abrasive belt in the desired path. This method consists of angularly tilting the head or driving pulley about a pivot point within the confines of the pulley, this pivot point being preferably located on the geometric center of the pulley. In the present instance this pivot point is located at the point 0 defined by the intersection of the axis of the shaft 50 and the radial plane passing thru the center of the self alining bearing'42. In the embodiment disclosed, the shaft 50 and hence the pulley 64 is tilted by displacing the axis of the shaft 50 horizontally in opposite directions from a normal position, the mechanism for effecting this horizontal tilt being controlled by an actuating device which responds to deviations of the belt from the normal path. The mechanism for horizontally tilting the head or driving pulley wilI now be described.

Head pulley tilting mechanism As previously described, the shaft 50 is mounted in bearings 42 and 46, the bearing 42 being fixed in the housing 25 and serving as a pivot about which the shaft may be angularly tilted and the bearing 46 being supported in a horizon'tally shiftable bearing block or housing 51. This block 51 is provided at its lower edge with a horizontal track member or race 9I supported on an anti-friction roller structure 92 which is.

in turn supported on a track or race 93 fixedly secured to the bracket 32 as best appears in Figures 7 and 9. Serving as an additional overhead guide for the bearing block 51 are a track or race .94 mounted along the top of the block, an antifriction roller structure 95 and a race 96 secured to an upper Ihorizontal wall of the bracket 32.

As will be understood, the bearing 46 and the bearing block 51 and associated parts are readily shifted horizontally with a minimum of mechani-:

cal effort.

FiXed tothe bearingblock 51 at the rear end orleft'end of the machine as viewed in Figures 8 and 14, or on the right end as viewed in Fig. 9, is a pin-:9! upon which is mounted a telescoping. frame. "i.h is frame comprises upper and lower outer frame elements 98 and 99 which are mounted on the pin 91. Slidably engaging the elements 98 and 99- are upper and lower inner frame elements I69 and I6I, which are mountedon a pin;

I62 parallel to andspaced from the pin 91, upon which pin I92 is also mounted the head of an eyescrew I93. The shank of the eye screwis formed with a thread as indicated at I66 and is mounted for axial slidable movement in a pair of v spaced bosses I64 and 165 formed on the bracket 32. Mounted on the shank of the eye screw and formed with a threaded bore engaging the thread I66, is a bevel gear I61. Meshing with this bevel gear is a bevel pinion I68 suitably mounted on a-shaft rotatably supported in a boss I69 on the frame 32 and adapted to be rotated by any suitable manual or power means such asthe hand wheel II'6 shown adjacentto the boss I69 in Fig. .8, but which may be located at any position conveniently accessible .to the operator.

Interposed between the pins 91 and I62 is a fluid actuated cylinder construction comprising a cylinder I I I, having ears mounted on the pin I62 and a piston actuated rod I12 mounted upon the pin 91. The piston rod and cylinder are preferably axially alined withtheeye screw I66 and horizontally alined with the shaft 56..

Integrally formed with and projecting upward- I 1y from the upper outer telescoping frame ele-* ment 96 and adjacent the respective endsof this frame element are ears H3 and I I4 having alined apertures in which are reciprocably mounted plunger rods I I5 and I I6. The upper inner frame element I96 is also formed with an upwardly projecting ear I I1 thisear passing thru a slot or recess in the element 98 and projecting upwardly beyond the uppersurface of. the element 98 .and

,being formed with an aperture alined with the apertures in the ears; H3 and H4 and adapted tosupport theradjacent ends of the plunger rods II5'and H 6 as best appears in Fig. 13. Collars H6 and H9 are formed intermediate the ends of each of the plunger rodsx-II5 and H6, these ubalancedhorizon'tal component of the tension of V .the abrasive andipower belts. Nuts I22 and I23 1 having threaded. engagement'with the outer ends 0f the plun er rodsare'provided to suitably posil t-ion the collarsIlfl and I19 with respect to the ears I I3 and. I'I4,as best appears in Fig.-l3. The ear H1 is formed-with a lateral offset portion I24, this offset portion being alined with adjustable stop screws I25 and I26 mounted in bosses on the element 98 and serving to limit the movement'of thescrews I25 and. I26 and hence the element 98 with respect to the element I69-.. I The lower elements 99 and IllI are each pro- 'vided'with ears, plungers, springs, and adjusting screws identical with those described with reference to the upper elements 98 and I66 as shown in the drawings. 6

The cooperation between the .parts just described is as 'followszfiThe bosses I64 and I65being integrallyfnrmed with .the bracket 32 -are relatively to the housing 25. Theeye'screw 63 altho slidably mounted in the bosses I641and l- 6 5 can'be longitudinally fixed with respect to bosses by the bevel gear 191 at any position within the range of the adjustment. .Thus I the pin'i62 and'the members I66 and :I6I ineluding the ears H! can be longitudinally fixed with respect to the frame 32; .Thesprings I26 and are relatively stiff and are so selected that they :wvill. transmit anylongitudinal movement or adjustment of the ear III tothe. ear H3 orto th f ear H14 :and thence to the elements: 63 and 99 and "thus to the .pin 91 and to the bearing block5'l. It is to be noted that the strength .of the springs I26 .and-IZI is cons'iiderably greater than the resistanceto horizontal movement offered by the anti-frictionally mounted bearing block 51; .It will appear from the above description that a change in the longitudinal position of theeye screw I63 and pin 6 I62 will produce a corresponding change .in the horizontal position of :the bearing block 51 and hence of theibearing'46 and of the far end of the shaft 56.

Assuming that the bearing block 51 has been located in the desired normal or neutralposition the manner described; if air is admitted to the cylinder III thru asuitable inlet I2I the piston 142a and piston rod H2 and pin 9I .wi1l bemoved to the left as viewed inl ig. 9 thus positively moving the pin- 9'I,.elements 98 and :69 and bearingblock 51 to the left and compressing thespringsIZI. The extent of this movement is limited, however, by the abutting of the stop screxv I26 against the offset portion I24 on the ear II'I after which abutment no further movement of the piston can take place. This admission of air thru thejinlet I27 accordingly causes a horizontal shift in the bearing 46 and the far .side of the shaft 56 to the extent permitted bythe stop. screw I26. As soon as the air pressure is released thru the opening 62-1, the spring I2I again expands until a conditiono-f equilibrium .is established between the springs I26 and I.2I whereupon theparts will again have been returned to the positions shown in Figures 9, 10 and l3. y

If, on the other hand, air pressure is admitted to the inlet opening I29, the piston H21; and piston rod II2 are moved toward the right as viewed in Fig. 9, causing the pin 91 likewise to move toward the right thus moving the bearing blockfi! and the elements 96 and 99 toward the right. This movement causesthe springs I26 to be compressed and causes the bearing 46 tomoye to theright .(as viewed in Fig. :9) the extent of this movement being. limited by: the abutment ofgthe stopv screw, I25 against the ear III. Upon the release of theair pressure thru the opening I28 .theparts will again resume the neutral positions shown in Figures 9 and 10 by the springs I20.-

expanding action of the 1 It will be evident from the above that if the passage of air to the cylinder is :suitably controlled the piston in the cylinder III and hence the piston rod IiIZ will cause the bearing 46 to be horizontally shifted in either direction from its normal or neutral position. It will also be evident, particularly from an inspection of Fig.

14, that the shiftingof the bearing 46 will-cause the head shaft 50 and hence'the head pulley 64,

'to tilt about the'center c of the fixed or pivot bearing 42. This tilting will be clockwise or counterclockwise as viewed in Fig. 14 depending upon the direction of the actuation of the piston and nism being illustrated inFig; 2. In this figure,

an air pressure supplytank is diagrammatically shown at I30 from which a suitableair inlet I3I-leads to the four way solenoid actuated valve I32. From this-valve a line I33 leads to the inlet opening I21 at the head end of the cylinder 3 III and a corresponding line I34 leads to the inlet opening I28 at the piston rod-end of the cylinder. Suitable air exhaust openings I35, I35

are provided in the air valve I32 to permit the air pressure applied to the piston to escape when the piston is to .be returned to the neutral posi- 'tion or is tobe reversed. This air valve may be of any well known standard design and since this valve per se forms no part of this invention it? need not be described in detail.

, -Device s for controlling tilting mechanism The control device for actuating the head pulley tilting mechanism will be best understood by reference to Figures '1 to 5, inclusive, and comprises electrically energized solenoids shown at "I36 and I31 these solenoids being mounted in any convenient position on the frame of the ma- "chine, in suitable relation tothe valve I32. Each solenoid I36 and I31 is provided with a vertically movable plunger indicated at I38 and I39, re,- spectively. Also supported on the frame of the machine in suitable relation to the valve I32 and solenoids I36 and I31 is a pair of bell crank levers I40 and MI each associated with one of the solenoids and adapted to actuate the :four way valve I32 to'introduce air under pressure .int'o'one or the other of th lines I33 or I34 running to the cylinder III. As'shown in the drawings, the solenoid I31 when energized is adapted to actuate the valve I32 to introduce -'=air under pressure thru the line I34 and inlet -I28 into the piston rodlend of the cylinder III and the solenoid I36 when energized is adapted to introduce'air under pressure thru the line I33 and inlet I21 into the head end of the cylnder. v

The solenoids I36 and I31 are selectively and intermittently energized by a control device indicated in its entirety at I44 and including elecfrom a predeterminednorrnal path.

: The solenoid I35'is associated with the circuit I45 which is adapted to be energized by the .switch. I41 and the solenoid I31 is associated with the circuit I46 which is adapted to .be energized bythe switch I48, as appears in Figures 2.,to 5 inclusive. The above described solenoid controlled valve mechanism and the control device I44 are in principal substantially similar to the corresponding elements disclosed in my copending application Serial No. 337,326 and the herein disclosed control device is practically identical with the device, illustrated in Figures 11 to 15 of that application, and need only be briefly described here. The. present control device, like the earlier device just referred to is located adjacent one edge of thetravelling belt and is responsive to the movement of one edgeonlyof the travelling belt and'is preferably positioned generally symmetrically about this edge of this belt ,asrwill appear bestfrorn reference to Figures 2, f1 and 5 of th present application.

.The mercury switches I41, and I48 are supported in a suitable casing I49 this casing being mounted on an air inlettube I50 which is axially and rotatably adjustably mounted in a bracket I5I preferably supported from one of the contact pulley stands 86 as shown in Figures 1, 6 and 14. It will therefor be seen thatthis casing may be laterally shifted with respect to the belt to locate the control devices in various lateral positions corresponding to the desired or necessary location of the edge of the belt which is intended to actuate the devices. A set screw or other suitable means may be used for fixing the casing and. tube I50 in the desired position.

The mercury switches I41 and I48 are each formed with two spaced contacts located at one end of an enclosing glass tube, these contacts maintaining the circuit open when the tube is tilted to position the mercury in that end of the tube opposite the contacts. These mercury switches are each mounted on a shaft pivotally supported in the casing preferably in anti-friction bearings. Also mounted on these shafts and at points on opposite sides outside of the casing are controllevers I52 and I53, the lever I52 being associated with the mercury switch I41 and the lever I53 being associated with the mercury switch I48. The control levers in the embodiment shown, pass upwardly around the respective sides of the casing I49 and toward each other and toward the center of the casing as is best shown in Fig. 5. At the inner or adjacent ends, these control levers are each provided with a relatively light flat plate, vane or spoon, indicated. at I54 and I55 respectively,

adapted to serve as an abutment for spaced jets of air presently to be referred to. The leversI52 and I53 and vanes I54, I55 normally assume a position by gravity, each resting against a stop pin, this being the position occupied by the lever I52 and vane I54, as bestappears in Fig. 3. Secured to the upper face of the casing I49 is an angle bracket having a vertically disposed wall portion substantially paralleltothe wall I56 in which portion a pair of nozzles I and I6I are located, these nozzles being axially alined with the apertures I51 and I58, respectively. Air under pressure is supplied to the inlet tube I50 and thence to the branch tubeil59 this air issuing fromthenozzlesin relatively fine. streams which, unless obstructed; pass *thru the. aperturesi'l5'l and I58 and impinge against the vanes I54 and I55 and which have sufficient kinetic energy to overcome. the slight" force of gravity acting on the vanes and" associated parts thus tilting the associated vanes, levers and mercury switches from the position which they normally occupy by gravity.

As will appear, the nozzles are positioned adjacent the rear or smooth face of the belt, that is on the opposite side of the'abrasive belt from the wall I56 and vanes I54 and I55, and are positioned to straddle the edgeof thebelt when the belt is travelling in the desired path, as clearly shown i'nFigures 2 and 4. As a; result of the arrangement described, the air jet from the nozzle ISO, in normal operation, impinges against the belt'being thereby blocked fromimpinging against the vane I54 and thus permitting the vane I54 and associated lever I52 and switch I41 to assume the position which itnor mally occupies by gravity, while the air'jet from the nozzle I6I passes past the edge of the belt thru the aperture I58 and impinges against the vane I55 thus displacing the vaneul55 and associated lever I53 and switch I48 from the posi tion which it would normally-occupy by gravity; The terminals in the mercury switch I4'I are so positioned that the circuit controlled by the switch I4! is open when the switch and vane are in position shown in Fig. 3, that. is the position which they occupybygravity; The switch I48, on the other hand, is so arranged that the circuit controlled by the switch is open when this switch and vane are in the position shown in Fig. 3, that is when the associated air jet I6! is impinging against the vane.

It is to be noted that two stop pins are provided on each sideof the casing I49 to serve to stop the levers I52 and'l53 in the desired terminal positions as best illustrated in Figures 3 and 4. Both of the switches I41 and I48 are arranged to close the respective circuits controlled by them when the switches are respectively in the alternate positions from those shown in Figuresl to 5'; that is when thellever I52 is forced against the right hand pin and when the lever I53 is resting by gravity against the left hand pin as viewed in Fig. 3. The wall I55 is providedprimarily to'protect the delicate vanes and control levers'from serious damage in the event of a tear or break in the abrasive belt.

Head pulley brake The'momentum. of the head pulley dueto its large size and comparatively rapid rotation is relatively great and due to the anti-friction mounting of its shaft normally continues to r0- tate. for a substantial period of time after the power is shut off. In order to eliminate the disadvantages incident to this prolonged rotation, and in order to provide almeans for rapidly stopping the head pulley in an. emergency, a suitable brake mechanism is provided.

Thismechanism as bestappears in Figures 6 and-8 consists of a brake. drum I62 provided on the power pulley 60 and a bracket I63 mounted, on. the horizontal shiftable bearing block 51 andsupporting a. pin I64 upon which are mounted the lower ends of a pair of brake shoes I65, I65. These shoes are adapted to be moved into braking engagement-* with the inner face of the drum by means of a suitable air cylinder I65 interposed between the upper or movable ends of the brake shoes. As will be understood, the suitable application of air pressure to the air cylinder I66 causes the shoes to expand into'engagement with the inner face of the drum and the-rapidity of braking will be proportional to the intensity of pressure applied to the cylinder I66; I

Operation of grinding mechanism The operation of the grinding mechanism of this improved machine will readily appear from the preceding description and from the draw ings, supplemented by a brief further explanation.. r

In the drawings, the machine is shown in a non-operating or non-grinding position but the parts of the machine are assumed to be in correctly adjusted positions'ready for proper operation and the parts are further assumed to be in motion just preliminary to the actual grind: ing. It is accordingly assumed that the strip W to be ground has. been properly centeredv on the billy roll 4 and. thatjt has been properly tensioned and that it hasbeen caused to travel. in: the direction indicated in Fig. 1. It is further assumed that the abrasive belt hasbeen properly mounted on the large head pulley 64 and on the contact pulley 89 and that the abrasive belt has been correctly tensioned by vertical adjustment of the. head pulley and that the drive belts have been correctly tensioned by vertical adjustment of the drive motor BI and that the motor has been started, causing. the abrasive belt to travel in the. direction indicated in the several views. Itis also assumed that the head pulley has been properly angularly tilted with respect to the contact pulley to cause the abrasive belt to. travel in the desired path, this tilting having, been effected by the proper horizontal shifting of the bearing 46 by means of the mechanismand method described hereinbefore under the heading Head pulley tilting mechanism. It is also assumed that the. billy roll 4 has beenproperly positioned horizontally and in parallel relation with reference to the. contact roll 89 and that the bushings I2 have been accurately vertically adjusted to properly space thebilly roll from the abrading belt to produce the desired thickness of the finished strip W, this being effected by means of the mechanism and in themanner. hereinbeTore'described under the heading of Work supporting means.

All of the elements of this machine having been properly adjusted and set in motion, as pointed out. air under pressure is simultaneously admitted to the cylinders H! which cause the pistons 9, piston rods 8, bearings 3 and billy roll 4 to move upwardly to the predetermined position in which the collars H on thepiston. rod 8 engage the bushings I2 thus causing the travelling strip W to be positioned in proper grinding relation to the abrasive belt.

The characterof the finish produced by the abrasive belt can immediately andclearly be inspected as soon as it emerges from the grinding area this being made possible by the substantially vertical approach of the abrasive belt toward the If the depth of the grinding is too great or not suiiiciently deep, corresponding adjustments can be made by the operator while the grinding progressing by suitably turning the bandwheel til. Means may also be provided to instantly reverse the direction of travel of the strip W in the event that the initial grinding has not completely eradicated surface defects and a local orcomplete re-grinding is necessary.

When the grinding of the strip has been completed or when it is desired to' interrupt the grinding operation for any'o'ther reasonQit isonly necessary for the operator to'release' the air pressure from the lower faces of the pistons 6 in the cylinders lfl whereupon the billy roll 4 and the strip W, drop, aided by air pressure on the upper face of the piston, if necessary, to the position spaced from the beltas shown in the drawings. If it becomes necessary or desirable to quickly stop the rotation of the head pulley 64 this can be effected by applying air pressure to the air brake cylinder I66 in the head pulley brake as hereinbefore explained. I

Operation of belt guiding mechanism Inthe position of the parts as shown in the drawings, the abrasive belt is assumed to be running in the desired predetermined path. In this. position .of the beltthe nozzles I60 and l6I are positioned to straddle the edge of the belt as clearly shown in Figures2, 4 and 5. Accordingly the air jet fromth'e nozzle I60 impinges against the belt,,90..and .is, blocked, from, reaching the vane l54thus permitting thelevjer I 52 to gravitationally hold-the switch I41 in the open position. The air jet from the nozzle I6I on the other hand, clears the edge ofthe belt 90 and impinges against the vane I55 thus displacing the lever I53 from its gravitational position and maintaining the switch I48 in the open position. r V

Uder the above circumstance, thatis when both switches I41 and, I48 are open, both solenoids: I36 and .131 are de-energized andthe four way valve I32 is, in the position in which it releases the pressure from both ends of the cylinder III and the springcontrolled.plungers H5 and I I6 maintain the bearing 46 and hence the head shaft 50 and the headpulley 64 inthefnormal position thus tendingto maintain the web travelling in the desired predetermined path, these spring controlled plungers, H5 and H6 likewise causing the piston to assume an intermediate position between the ends of the cylinder III.

As pointed out, however, the travelling belt is subject to lateral deviations from its desired path and the hereinbefore described head pulley tilting mechanism and. control device constitute belt guiding mechanism intended to return the belt to its normal path of travel in the event that the web hasmeandered, for any reason, from the normal path and this is effected as follows:

Suppose it be assumedthat the abrasive belt shifts toward the far side as viewed in Fig. 1, that is to the right asviewed'in Figures 2 and 6.. In this event, the edge of the web will approach the jet issuing from the nozzle I6I and will eventually intersect the path of this jet and interrupt or block this jet from reaching the vane I55 on the lever I53. Under these circumstances the vane I55 and lever I53 swing downwardly to the left bygravity, that is in a counterclockwise direction as viewed in Figures 2 and 3, being freed from the restraint of the jet. The downward positioning of the lever I53 causes the mercury switch I48 to close the circuit I46 which in turn energizes the solenoid I31. The energizing of this solenoid lifts the plunger I39, this in turn tilting the bell crank lever I4I to so actuate the four way valve I32 as to introduce air thru the line I34 into the piston rod end of the cylinder III. This air pressure causes the piston H211 to move toward the head end of the cylinder thus moving the piston rod I I2, bearing'block 51 and bearing 46 to the left as viewed in'Figures 2, 8, and 14, that is, to the right as viewed in Fig. 9, and compressing-the springs 5 I20. This movement causes'the far end of the shaft 50 "to shift or tilt to the left as viewed in Fig. 14, this tilting or pivoting taking place about the center 0 of the bearing 42. This tilting of the v head shaft causes a corresponding tilting of the 10 axis of'th'e head pulley with respect to the axis of the contact pulley and this counterclockwise shifting of the pulley'about the center 0 as viewed in Fig. 14 tends'to return the belt to its normal position, that is it tends to move the belt pro- 15 gressively toward the near side.

After this belt has travelledlaterally toward the near side a'sufiicient distance to reach substantially its normal path, the jet issuing from the nozzle I6I willa'gain'be unblocked, that is it will '20 again clear the edge of the beltand be free to impinge against the vane I55 on the lever I53, thus'causingthe switch I46 to move to the open position'and thus tie-energizing themagnet I31 whereupon the plunger I39 drops to permit the valve I32 to shift to its neutral position in which the air is released'from bothsides of the cylinder I I l. The pressure against the piston having been released, the expansion of the springs I20 again shifts the bearing block 51 to the right as viewed in Fig. 14 and hencetilt the shaft 50 back to its normal running position and the head pulley will again be so positioned that the belt will continue to travel in the normal path. It is to be noted that v the stop screw I25 limits the extent to which the 35 shaft 50 is tilted during the corrective action.

'If the belt should travel to the near side of the machine, that is to the left as viewed in Figures 2 and 6, it will unblock the jet issuing from the nozzle I60,thus permitting this jet to impinge against the vane I54 and tilt the lever I52 and switch I41 to a position in which the switch I41 closes the circuit I45 thus energizing the solenoid I36 causing the plunger I38 and associated bell crankI40 to actuate the valve I32 to introduce air under pressure thru the line I33 into the head end of the cylinder III which causes the bearing block 51 and the bearing 46 to move to the right as viewed in Figures 2, 8, and 14 thus compressing the spring I2 I and shifting the far end of the shaft 50 50 toward the right and tilting the head pulley 64 in a clockwise direction, as viewed in Fig. 14, about the center 0. This tilting causes the belt to progressively traveltoward the far side. This tilted position is maintained until the belt has substantially reached its normal path at which time the jet issuing from the nozzle I is again blocked by the'belt thus permitting the vane I54, lever I52 and switch I41 to tilt to the position in which the switch is open, thus tie-energizing the solenoid I36 and thus controlling the valve I32 to permit the air to escape from the cylinder I I I whereupon the compressed spring I2 I, again shifts the bearing 46 to the normal position and tilts the head shaft 50 to its normal running position in which it normally maintains the belt travelling in the desired path.

It will be seen from the above description that thetilting of the head or abrasive belt driving pulley and the corrective shifting of the abrasive belt is initiated in response to any excessive deviation from the desired predetermined path of travel of the belt.

, General It will be evident that in the herein disclosed belt type grinding and polishing machine the number of rapidly rotating parts has: been reduced to an absolute minimum and that the proportionately very large head pulley reducesthe objectionable vibration producing capacity of the rotating parts of this machine, and that the improved association of relatively verylarge and very small pulleys eliminates the destructive bending strains on the-belt, and that the selection of the relativelyvery largedriving pulley reduces the tension which must be applied to prevent the slipping of the belt, and the relatively close mounting of the large and small belt; pulleys produces a very compact unit, andeliminates belt whipping, and the tiltable mounting of the driving head pulley about a center within the confines of the pulley produces a simplified. mechanism for the guiding and/or centering of an abrading belt traveling over a, pair of, spaced pulleys, and that this machine, otherwise fulfills. the objects set forth, in the beginning of this specification.

Many modifications of this invention. andits application. will. naturally occur, to thoseskilled in this art and the present disclosure should therefore be considered. as, typical only, and. I desire not to be limited. to theexact constructions shown and described.

Inasmuch, as this invention is unconcerned with the specific character of the workmaterialior of the work-treating belt, the terms abrasiveand the like, and work and the like, used herein. and in the appended, claims are intended broadly to include within their comprehension any and all materials towhich themachine which constitutes this invention cantbe applied, as will be understood, by those skilled in the art.

It is to benoted that certain features disclosed in this application and not claimed herein, are claimed in my co-pending application Serial No. 337326 filed May 25, 1940, now Patent No. 2,274,- 268 of February 24, 1942: and. in. my co-pending application Serial No. 338,175 filed May 31, 1940, now Patent No. 2,316,582 of April 13, 1943.

What I claim is: 1

I. A machine of the character described including in combination, a driving: pulley having a relatively large diameter, a contact pulley having a relatively small diameter. an endless abrasive belt mounted. on said pulleys, thebelt comprising two portions engaging the peripheries of the pulleys and maintained by the pulleys against vibration and two unsupported; strands intermediate the periphery engaging portions, said unsupported strands being inherently subjected to vibration, the spacing of said pulleys being such that the length of each strand of unsupported belt does not exceed one andone half times the length of the periphery of the said contact pulley whereby the length of belt subject to vibration is kept relatively small, means for actuating the driving pulley, and a" work support juxtaposed to said contact pulley.

2. A machine of the character described including in combination, a driving pulley'having a relatively large diameter, a contact pulley having a relatively small diameter, an endless belt mounted on said pulleys and having bonded thereto an abrasive coating which tends to separate upon severe bending of the belt, the belt comprising two portions engaging the. peripheries of the pulleys and two unsupported strands intermediate the periphery engaging portions, the includedangle betweenthe unsupported strands being greater than eighty degreesr whereby. the

bendingxst'resses imposed? on the belt by thecontact: pulley are. kept within safe limits, means for actuating the driving pulley, and a work support juxtaposed tosaid contact pulley;

3. A machine of the'character described, ineluding in combination, a driving pulley havinga relatively large diameter, a contact pulley hav ing' a relatively small diameter, an endless abrasive belt mounted on said' pulleys, the belt'comprising two portions engaging the peripheries of the pulleys so as to be cooled thereby and two unsupported strands intermediate the periphery engaging portions; the arc of contact of the' abra sive belt on the periphery of the driving-"pulley being in excess of two hundred sixty degrees so that the cooling effect of said pulley on the for actuating;

prising two portions engaging theperipheriesof;

the, pulleys so as to, be cooled thereby and two unsupported strands intermediate the periphery, engaging portions, the lineal, length of. the portion. of. the. belt engaging the periphery. of the driving, pulley comprising morethanfiijty percent of. the, total lineal length of the. belt so that the. major portion, of. the belt is at, all:

timescooledbysaid pulley, means for actuating the driving, pulley. and a work posed. to, said, contact pulley.

5. In. a machine of. the character described, a supporting. frame, a. work support; a. rotatable contact pulley juxtaposed to the work support,.a

head pulley. rotatably-mounted in theframe,, an endlessabrasive belt mounted onsaid pulleys,:the diameter of said contact pulley being less than one sixth of the diameter of the head pulley, the axes of-said pulleys being spaced from each, other distance substantially less than thediameter of thehead' pulley whereby the portion of-thebelt which is unsupported.- by engagement with said pulleys is rendered substantially small, power means for driving. one-ofsaid pulleys, and'means for moving; the worksupport radially'towardand away from the contact pulley so as to control the. application. of the portion of abrasive belt instantaneouslyon' the contact pulley towork on the worksu-pport;

6. In awmachine ofthecharacter described; a supporting frame, a work support; a rotatable contact pulley'juxtaposed' tothe work support. a head pulley rota-tably mounted in the frame, and endless abrasive belt mounted onsaid pulleys; the diameter of said contact pulley being less than one sixth of the diam'eterof'the headpulley and the peripheries of the pulleys" being spaced apart a distance less than substantiallythe diameter of the contact pulley whereby the'portions of the belt which are unsupported by engagement With-the pulleys are rendered substantially small the included angle between said unsupported portions is relatively large, power means for driving one of said pulleys, and means for moving the work support radially toward .and away from thecontact pulley so as to, control theapplication. of. the portion of. abrasive belt instantaneously onthe. contact pulley to workonthe work support.

support, juxtamounted on ,saidpulleys, and power means for drivingone of said pulleys, whereby the vertical spacing of the axes of the contact and head pulleys is reduced substantially to a minimum and the strand of belt extending to work issuing-from the contact pulley is substantially vertical so that the effeotof the belt on the work can be observed substantially at the line of contact between. the work and the contact pulley.

Y 8. A' machine of the character described including, incombination, an endless abrasive belt, pulleys for. supporting and driving the belt, said pulleys consisting of afdriving pulley of relatively large diameter and a contact pulley of relatively small diameter and said belt comprising two portions engaging the peripheries of the pulleys and maintained by the pulleys against vibration and twounsupported strands intermediate the periphery engaging portions, said unsupported strands being inherently subject to vibrations, means for tilting theaxis of one of said pulleys for correctively'guiding the belt around said pulleys, the spacing of said pulleys being such that the length of each strand of unsupported belt does not exceedone and one half times the length of the periphery of the contact pulley, whereby the length of belt subject to vibration is kept relatively small, means for actuating the driving pulley, and a work support juxtaposed to the contact pulley.

'9. A-machine of the character described including, in combination, an endless abrasive belt, ,pulleys for supporting and driving the belt, said pulleys consisting of a driving pulley of relatively large diameter and'a contact pulley of relatively smalldiameter and said belt having bonded there to an abrasive coating which tends to separate upon severe bending, said belt comprising two portionsengaging the peripheries of the pulleys andtwo unsupported strands intermediate the periphery engaging portions, the included angle between the unsupported strands being greater thaneighty degrees whereby the bending stresses imposed on the belt by the contact pulley are kept within safe limits, means for tilting the axis of one of the pulleys for correctively guiding the belt around said pulleys, means for actuating the drivin pulley, and a work support juxtaposed to said contact pulley. v

.10; A machine of the character described including, in combination, an endless abrasive belt, pulleys for supporting and driving the belt, said pulleys consisting of a driving pulley having a relatively large diameter and a contact pulley having a relatively small diameter and said belt comprising .two portions engaging the peripheries of the pulleys so as to be cooled thereby and two unsupported strands intermediate the periphery engaging portions, the arc of contact of the abras'ive belt on the periphery of the driving pulley being excess of two hundred sixty degrees so that the cooling effect of said pulley on the belt '7. In" amachine of the character described, a supporting; frame, a horizontal'work support, a

is relatively great, means for tilting the axis of one of the pulleys forcorrectively guiding the belt around said pulleys, means for actuatin the driving pulley, and a work support juxtaposed to said contact pulley.

11. A machine of the character described including,in combination, an endless abrasive belt, pulleys for supporting and driving the belt, said pulleys consisting of a driving pulley'of relatively large diameter and a contact pulley of relatively small diameter and said belt comprising two portions engaging the peripheries of the pulleys so as to be cooled thereby an two unsupported strands intermediate the periphery engaging portions, the lineal length of the portion of the belt engaging the, periphery of the driving pulley comprising more than fifty percent of the total lineal length of the belt so that the major portion of the belt is at all times being cooled by said driving pulley, means for tilting the axis of one of the pulleys for correctively guiding the belt around said pulleys, means for actuating the driving pulley, and a work support juxtaposed to said contact pulley,

12. In a machine of the character described, a supporting frame, a work support, an endless abrasive belt, pulleys mounted on the frame for supporting and driving the belt, said pulleys consisting of a contact pulley juxtaposed to the work support and a head pulley, the diameter of the contact pulley being. less than one sixth of the diameter of the head pulley, the axes of said pulleys being spaced from each other a distance substantially less than the diameter of the head pulley whereby the portion of the belt which is unsupported by engagement with said pulleys is rendered substantially small, means for tilting the axis of one of the pulleys for correctively guiding the belt around said pulleys, power means for driving the head pulley, and means for moving the work support radially toward and away from the contact pulley so as to control the application of the portion of abrasive belt instantaneously on the contact pulley to work on the work support.

13. In a machine of the character described, a supporting frame, a work support, an endless abrasive belt, pulleys mounted on the frame for supporting and driving the belt, said pulleys consisting of a contact pulley juxtaposed to the work support and a head pulley, the diameter of the contact pulley being less than one sixth of the diameter of the head pulley and the peripheries of the pulleys being spaced apart a distance less than substantially the diameter of the contact pulley whereby the portions of the belt which are unsupported by engagement with the pulleys are rendered substantially small and the included an gle between said unsupported portions is relatively large, means for tilting the axis of one of the pulleys for correctively guiding the belt around said pulleys, power means for driving one of said pulleys, and means for moving the work support radially toward and away from the contact pulley so as to control the application of the portion of abrasive belt instantaneously on the contact pulley to work on the work support;

14. In a machine of the character described, a supporting frame, a head shaft, a pulley fast on one end portion of the shaft, a pair of spaced bearings'rotatably supporting the shaft, a support for one of the bearings mounted for lateral movement with respect to the frame, the other bearing being pivotally mounted in the frame, said pivotally mounted bearing being interposed between the movable bearing and the fastening for the pulley on the shaft, means for shifting the movable support, power means for rotating said shaft, a second pulley fixably supported relatively to the frame, an endless abrasive belt mounted on said pulleys, and work supporting means juxtaposed to one of said pulleys.

15. In a machine of the character described, a supporting frame, a head frame slidably mounted on the supporting frame, a shaft mounted in the head frame, a pair of spaced bearings rotatably supporting the shaft at points spaced from the ends of th shaft, a pulley adapted to support an abrasive belt mountedon one end of the shaft, a power receiving pulley mounted on the other end of the shaft, one of said bearings being disposed substantially centrally Within the confines of the abrasive belt supporting pulley and the other bearing being disposed adjacent the power receiving pulley, and means for adjusting the latter bearing in a direction normal to the direction of sliding of the head frame.

16. In a machine of the character described, a supporting frame, an endless abrasive travelling belt, a pair of spaced pulleys about which the belt passes, said pulleys consisting of a contact pulley mounted on an axis fixably supported on the frame and a driving pulley, a shaft on which the driving pulley is fast, two bearings mounting the shaft on the frame, one being a pivot bearing disposed within the confines of the driving pulley, a slidable block mounting the other bearing for shifting the same to pivot the shaft about the pivot bearing, means connected to the slidable block to slide the same and thereby shift the path of travel of the belt, and Work supporting means juxtaposed to the contact pulley.

17. In a machine of the character described, a supporting frame, an endless abrasive travelling belt subject to lateral deviations from a desired path of travel, a pair of spaced pulleys about which the belt passes, one of said pulleys being a contact pulley mounted on an axis fixably supported on the frame and the other of said pulleys being a driving pulley, a shaft on which the driving pulley is fast, two bearings mounting the shaft on the frame, one being a pivot bearing disposed within the confines of the driving pulley, a slidable block mounting the other bearing for shifting the same to pivot the shaft about the pivot bearing, control mechanism responsive .to deviations of the belt from the desired path of travel connected to the slidable block for shifting the same, and work supporting means juxtaposed to the contact pulley.

18. In a machine of the character described, a supporting frame, an endless abrasive travelling belt, a pair of spaced pulleys about which the belt passes, one of said pulleys being a contact pulley mounted on an axis fixably supported on the frame and the other of said pulleys being a driving pulley, a shaft on which the driving pulley is fast, two bearings mounting the shaft on the frame, one being a pivot bearing disposed within the confines of the driving pulley and substantially centrally of the face of the driving pulley, a slidabl block mounting the other bearing for shifting the same to pivot the shaft aboutthe pivot bearing, means connected to the slidable block to slide the same and thereby shift the path of travel of the belt, and work supporting means juxtaposed to the contact pulley.

19. In a machine of the character described, a supporting frame, an endless abrasive travelling belt, a pair of spaced pulleys about which .the belt passes, one of said pulleys being a contact pulley mounted on an axis fixably supported on the frame and the other of said pulleys being a driving pulley, a shaft on which the driving pulley is fast, said shaft having a portion extending out beyond the frame, a power pulley on the end of said extending portion of the shaft having a driving belt engaged therewith, two bearings mounting the shaft on the frame, one being a pivot bearing disposed within the confines of the driving pulley, a slidable block mounting the other bearing on the portion of the fram adjacent to the power pulley for shifting said other bearing to pivot the shaft about the pivot bearing, means connected to the slidable block to slide the same and thereby shift the path of travel of the belt, and work supporting means juxtaposed to the contact pulley.

20. In a machine of the character described, in combination, a plurality of axially spaced shafts, a pulley mounted on each shaft including a driving pulley fast on its shaft, an endless abrasive belt mounted on said pulleys, a support for the drivin pulley shaft adapted to permit the tilting of the shaft, means for correctively guiding the belt around said pulleys comprising mechanism for tilting the driving pulley shaft, means for driving the tiltable shaft, and brake means including a brake drum mounted on the tiltable shaft adapted when actuated to retard the rotation of the driving pulley, and manually controllable means for actuating the brake means.

21. In a machine of the character described, in combination, a plurality of axially spaced shafts, a pulley mounted on each shaft including a driving pulley fast on its shaft, an endless abrasive belt mounted on said pulleys, bearings mounting the driving pulley shaft including a shiftable bearing and a pivoted bearing, means for shifting the shiftable bearing so as to tilt the shaft about the pivoted bearing for correctively guiding the belt around said pulleys, means for driving the tiltable shaft, brake means including a brake drum mounted on the tiltable shaft adapted when actuated to retard the rotation of the driving pulley, and manually controllable means for actuating the brake means.

22. In a machine of the character described, in combination, an endless abrasive belt, a relatively large driving pulley and a relatively small contact pulley about which pulleys said belt passes, tiltable shaft means for supportin said driving pulley, power means for rotating said shaft means,

and brake means including a brake drum mounted on the tiltable shaft adapted when actuated to retard the rotation of the driving pulley and manually controllable means for actuating the brake means.

23. In a machine of the character described, in combination, an endless abrasive belt, a relatively large driving pulley and a relatively small contact pulley about which pulleys said belt passes, a shaft fixed to the driving pulley and supporting the driving pulley, power means for rotating the shaft, means for rotatably supporting the shaft including at least one shiftable bearing, brake means interposed between the shaft and the shiftable bearing adapted, when actuated, to retard the rotation of the shaft and manually controllable means for actuating the brake means.

LAD L. HERCIK.

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