US2043972A - Centerless grinding machinery - Google Patents

Description

J1me 1936- G. E. MERRYWEATHER 2,043,972

CENTERLES S GRINDING MACHINERY Filed March 2, 1925 4 Sheets-Sheet 1 Jung 9, 1936. G. E. MERRYWEATHER 2,043,972

CENTERLESS GRINDING MACHINERY Filed March 2, 1925 4 Sheets-Sheet 2 aAA c 'rvi/ June 9, 1936. e. E. MERRYWEATHER 2,043,972

CENTERLESS GRINDING MACHINERY Filed March 2, 1925 4 Sheets-Sheet 3 'June 9, 1936. G. E. MERRYWEATHER 2,043,972

CENTERLESS GRINDING MACHINERY Filed March 2, 1925' 4. Sheets-Sheet 4 g wventoz George E. Merrywaafky Patented June 9, 1936 UNITED STATES CENTERLESS GRINDING MACHINERY George E. Merryweather, Cleveland, Ohio, as-

signor to Motch & Merryweather Machinery Company, Cleveland, Ohio, a corporation of Application March 2, 1925, Serial No. 12,493 15 Claims. (01. 51-103) This invention relates to improvements in centerless grinding machines and more especially to the method and apparatus for insuring proper rotative and feeding movements of the work piecesduring the grinding operation.

Broadly speaking the term centerless grinder is employed to denote a machine for grinding cylindrical or other work of circular form in cross section in which the W k is loosely held as distinguished from the ordinary type of cylindrical grinder in which the work is terminally supported by centers, chucks, or other mechanism during the grinding operation. Such a grinder normally comprises as its essential parts a support or rest for the work and a pair of members disposed at opposite sides of the support forming a work receiving throat. One of these members is a grinding wheel rotated at a suitable surface speed to produce proper grinding action or normally a speed of four to five thousand feet per minute. The other or feed controlling member in the centerless grinding art is normally in the form of a regulating member or wheel which frictionally engages the work piece and controls rotation thereof.

In centerless grinding prior to the present invention there have been two methods of operation, one known as the through feed, adapted for straight cylindrical pieces in which the pieces are moved axially along the work rest as by a relative angular relationship of the work-support and the operative path of movement of a point of one of the wheels at the throat which produces a feeding component to urge the work axially along the work rest. The other form of grinding which it has heretofore been considered necessary to emplay in connection with taper work, formed work and the like, is what is known as in-feed grinding. This consists in supporting the work between the grinding and regulating wheels without permitting its axial movement and subsequently withdrawing the work either by separation of the wheels or lateral displacementof the work.

This latter method, however, is open to the objection that considerable time is lost for the positioning and removal of the work so that in the past this form of grindinghas been relatively slower than the through feed method of grinding.

Also, with the former types of centerless grinders in commercial use it has been customary to make use of wheels formed from abrasive material for both the grinding and the regulating members due to the fact that the axial feeding of the work has been dependent upon the high friction component of the surface of the wheel having the angular path of movement and it has been believed a more positive feed with less liability to slippage could be obtained if the wheel exerting the feeding component were formed of 5 abrasive material. This, however, has the disadvantage that the pressure necessary to maintain the work against the grinding wheel tends to break down the abrasive faced regulating member and requires relatively frequent retruing thereof. This truing is particularly necessary in the case of in -feed operation when a particular form or configuration must be maintained on the surface of the regulating member.

It is the purpose of the present invention to do away with these difficulties experienced with prior art constructions and to make it possible to produce tapered or other formed work as well by the through feed method, as by the in-feed method, theobjectbelng to increase both the speed of production of the parts and the maintenance of the operative face of the grinding wheel.

A further object of the invention is the provision of mechanism which shall require much less frequent truing of either grinding or regulating member than has been necessary in the past and at the same time insure a maximum of accuracy of the finished product- An additional object is the provision of a structure in which it shall be possible to make use of a regulating member of other than abrasive material and preferably of a more permanent nature and to so construct such member that it will positively control the feed of parts through the machine independent of the frictional contact of the member therewith.

Further objects and advantages of the present invention should be apparent by reference to the following specification taken in connection with the accompanying drawings forming a part there- 40 of, and it will be understood that any modifications falling within the scope of the appended claims may be made in the specific details (if construction shown and described without departing from or exceeding the spirit of the invention.

Fig. 1 represents a front view of a machine embodying the present invention.

Fig. 2 represents a fragmentary plan view.

Fig. 3 represents a' vertical section as taken on the line 3--3 of Fig. 2.

Fig. 4 represents a fragmentary enlarged view illustrating the action of the work detaining finger.

Fig. 5 represents a perspectivewiew of the regulating wheel partially broken away. 66

Fig. 6 represents a sectional view taken as on the line 6--6 of Fig. 2.

Fig. 7 represents a vertical sectional view illustrating the employment of a force feed mechanism for the work pieces.

Fig. 8 represents a fragmentary front view of the machine embodying this feature.

Fig. 9 represents an enlarged diagrammatic view indicating the relative angular relationship of the parts.

Fig. 10 represents a fragmentary sectional view of a modified work rest illustrating the employment of a shifting work-supporting shoe.

Fig. 11 represents a fragmentary plan view showing the use of the specific type of shoe shown by Fig. 10.

Fig. 12 represents an enlarged view of the work throat of Fig. 10 with work piece therein.

The drawings illustrate one embodiment of the present invention which in its broad aspect comprises a bed A bearing the housing B having a grinding wheel C and bearing a second housing D for the regulating member designated as an entirety by the letter E. This regulating member is adjustable toward and'from the grinding member as by the screw F. It will be noted that the members C and E are in the form of discs peripherally opposed to form between them a contracted work receiving throat while projecting within this throat is a work rest G adapted to receive work from the trough or work guide H and discharge same into the chute I.

The foregoing parts broadly considered are characteristic of the present conventional commercial centerless grinder. The grinding member C is rotated downwardly as respects the work rest in the direction indicated by the arrow thereon and at a suitable grinding speed such as four thousand feet per minute while the regulating member moves upwardly adjacent the work rest as indicated by the arrow thereon in Fig. 1 and at a speed dependent upon the speed of rotation which is desired to apply to the work, this speed being at times as low as 15 R. P. M.

One distinction between the mechanism showing in the present drawings and that of the prior art, however, resides in the fact that hitherto in centerless grinding it has been customary to place the regulating member with its axis inclinedfrom the horizontal plane of the work rest so that as it rotates it will exert a feeding thrust or component diagonally of the work rest to gradually advance or axially shift the work piece. In the present invention, however, the members C and E may be placed either with their axes at an angle to cause a feeding component; or with their axes parallel with the work rest and with each, other, the feeding component being produced in a different manner.

As shown, the regulating member is formed from cast iron or other suitable material and with a circumferential progressively advancing helical path I 0. The several windings of the path are separated from each other by the intermediate continuous helical rib l I having a straight lateral face as at I 2 and an inclined or tapered face as at l3.

Attention is invited to the fact as clearly illus trated in Figs. 4 and 5 for example, that the path is not parallel to the axis of rotation of the regulating member but transversely considered is disposed at an angle so that it is tilted or tapered and approaches its axis of revolution more nearlyat one side than at the other.- The purpose of this will be best understood by reference to Fig.

2 from which it will be seen that there are a plurality of portions of the path in at all times in opposition to the grinding member C. The inclination of the bottom of the groove forming the path is such that if a taper work piece It is fed 5 into the path, the taper is taken up entirely by the inclination of the path, so that the several portions of the different rolls opposing the grinding wheel all lie in a straight line presenting a longitudinal element of the cones for operation 10 thereon by the grinding wheel.

v the base portion IQ of the roll engaging path.

This provides in the feeding groove an identically pitched and wound supplementary spiral groove intermediate the margins of the general groove as provided by the respective faces l2 and I3 of the rib M. This at the one time forms a clearance for the edge or terminus at the butt or larger end of the tapered roll and also facilitates accurate forming of both the terminal control surface It and the lateralcontrolling surface to.

Additionally, and as clearly illustrated in Fig. 11, the surface i0 is formed with a second depressed identically pitched and wound supplementary spiralgroove 5| providing clearance for the intermediate portion of the roll so that the regulating wheel engagement is with terminal portions only of the roll. This groove is laterally displaced as respects the median line of the path in, providing a relatively narrow rib or portion 52 for engaging the basal portion of the circumference of the roll, and a wider portion as at 53 for engagement with the smaller end thereof. In this manner an identically pitched and wound wide rib 53 adjacent the face I2 of rib II, and an identically pitched and wound rib 52 adjacent the face l3 are formed in the general angularly tilted grooved portion In which receives the rolls l4 and insures their proper presentation to the surface of. the grinding wheel. The taper work it is understood is of frusto-conical formation and the longitudinal bounding surface is therefore that of a portion of a cone or surface of revolution. In order to grind or produce the desired ultimate surface of revolution or form of taper member it is necessary that the grinding member contact with an element of the surface, that is to say that its point of contact must coincide with the theoretical longitudinal generatrix of the surface. To accomplish this result the one side of the cone must coincide with the grinding member C as indicated in Fig. 9. The axis 25 of the work piece will therefore be disposed at an angle to the grinding surface corresponding to the degree of taper to be produced. On the other hand the controlling surface or bottom of path I!) bearing against the opposite side of the work must have I been shown in Fig. 10 in which there has been provided the work rest guide 29 for the series of shoes 30 connected as an endless chain and having the inclined work-supporting portions 3|, the

front guide lugs 32 and rear lugs 33 for support ing the work. Rear lug 33 if desired may be formed with a projection 34 for cooperation with projection 35 of rib ll so that the rotation of the regulating member automatically causes the progressively advancing feed of the taper work supporting rests 30. The structure just described is shown in Fig. 11 which illustrates the use of a substantially triangular traveling work supporting shoe which feeds into the space provided by the taper of the regulating wheel and thus gives sufficient width for satisfactorily supporting the rear as well as forward portions of work pieces of pronounced taper.

By reference to Fig. 3 it will be seen that gravity causes the work pieces to slide down from hopper K throughout the tube H and tend to slide laterally along work rest 9: and into the path of the regulating wheel or drum. As this drum rotates a roll received in the path between the pair of the ribs, being held down by gravity, will be rearwardly engaged by the bevel face B of the rib H. Continued rotation therefore progressively shifts the effective portion of the path transversely of the grinding wheel carrying with it the engaged roller as clearly shown in the drawings. There is, therefore, a rotation of the work due to the lateral engagement of the regulating wheel with the side of the work piece as shown in Fig. 6 for example, coupled with a distinct means, to wit, the rib for feeding the work. The side of the rib i2 terminally engages the work piece and on account of its spiral movement during rotation of the controlling drum gradually axially shifts the work piece from entrance side to discharge side of the machine, the grinding taking place during the shifting as the work moves along the work rest G.

The width of the path has been shown greater than the length of the work piece to be received therein so that there will be no liability of wedging of over-length members, while to prevent piling up or wedging of the work pieces at the entrance to the path there has been provided a flange or plate portion 95 secured to the side of the control member as by screws I6 and having the beveled or sharpened entrant portion H. It will be noted that as the member E rotates in an upward direction each rib will have a receding eiiect and the tendency of the weight of a series of pieces on the guide it will be to urge the innermost work piece on the guide against the receding rib until it eventually enters into the complete path between the thread, or winding of the rib, it being shown in substantial entrant position in Fig. 4. As the width of the path is somewhat greater than that of an individual roll it would be possible for the end of a second roll to project into the path of the approaching initial or first thread as shown at it in Fig. 4. Should this occur the thread would tend to block upward the adjacent roll tip and thus interfere with the feeding action. To prevent this the member 85 is provided with a bevel edge ill. If the roll is of the right length the sharpened tip ill will act as a separation between the end of the rib engaging roll and the next adjacent roll as shown in Fig. 4, holding back the following roll until the thread rib comes around to a position where the roll may gradually follow in along the incline of the thread.

If for any reason it is felt desirable to make use of force feed for the work in place of depending solely on gravity a mechanism such as shown in Figs.- 7 and 8 for example may be employed. In this form the work guide is in the form of a tube 36 cut away in the lower portion as at 31 into which projects the endless belt 38 passing over. idler 39 and drive pulley 40. These parts are supported by bracket 4| on the bed A, suitable mechanism being employedfor driving the pulley 40. That shown comprises a gear 42 on the pulley shaft 43 meshing with-pinion 44 on drive shaft 45 carried by arm 46 of the bracket 4|. This shaft is further provided with the bevel pinion 41 meshing with the bevel gear 48 secured on the regulating wheel. The relationship of these parts is such that the belt exerts a continu- '1 ous inward pressure against the work pieces 14 holding them up against the outer surface of the guide rib or against the detaining plate l5 as the casemay be. Inasmuch as the upper portion of the tube 36 forms a top closure over the work pieces until they are received into the work path; and since use is made of the overlying guide or finger 49 extending into the grinding throat above the work piece, there is no-opportunity for friction between the work piece and the upwardly moving regulating wheel to displace the work'piecewhich therefore will be limited solely to a forward axial movement. On the other hand, the belt merely exerts a tractional friction against the rolls and there is no undue 3o pressure and no forcible feed action of a character which might in any deleterious way efiect the action of the grinding or regulating members.

It is to be understood that while the regulating member has been shown as adapted for use on taper work as the more dimcult form of grinding, said member is equally useful in connection with straight cylindrical or other work which it is desired to produce by the through feed method,

the face of the regulating member, however, be-

ing varied according to the desired ultimate longitudinal conflgurationof the work that is to be produced; 4 ,From the foregoing description taken in connection with the drawings, the struture and improved process of producing work pieces of circular shape in cross section should be readily apparent and it will be seen that there has been provided-anew process of taper grinding work pieces by the through feed method consisting in 50 supporting such pieces between the regulating member controlling by frictional engagement the rotation of such pieces and a grinding mem- I her for removing desired stock from the pieces,

characterized by the fact that the regulating I member has a work engaging portion of complementary configuration to that to be produced on the work and that said complementary portion in eifect is progressively advanced across the face of the grinding member to carry the work piece therewith.

The mechanism for the carrying out of this process it will be noted; broadly considered, in-' cludes a regulating member or drum having a circumferentially advancing helical path of irregular or varying transverse configuration so that a work piece of other than cylindrical form may be fed within the path. The rotation of the control member continuously progressively brings a corresponding surface in transverse section at longitudinally advanced points on the work rest so that the work piece is held on the work rest in constant and unvarying position in relation to the grinding member while being advanced across the surface of the member from receiving to discharge position. This transverse advancing of the work makes it possible to perform continuous grinding on a number of work pieces, four being illustrated, in place of but a single work piece at one time as has been customary with work of this character heretofore. It also possesses the additional advantage that by feeding such work pieces continuously across the face of the grinding member the straight face of said member is preserved and undue wearing at any particular point which occurs with in-feed grinding methods is eliminated.

Also by the use of a metallic or like regulating member it is possible to produce a very permanent form of path and of feeding rib which will not have to be trued except at very long intervals.

When desired to preform a truing operation the regulating wheel may be turned or ground off in any suitable manner. One form of mechanism for accomplishing this result comprises a small peripheral grinding wheel, 20, of proper transverse configuration to fit the bottom of the groove carried on the housing D by a slide 2| and vertically adjustable as by screw 22, the truing wheel being dropped down into the path and being suitably driven to grind off the path. As the regulating member is slowly rotated the wheel and its slide feed transversely along the groove thus restoring the path to its initial or desired configuration.

It is to be noted in connection with the present construction that in place of the feeding action being dependent upon the angular relationship between the member exerting the feeding component and the work rest and the frictional grip of said member, that the feeding action may be entirely dependent upon interengagement of a positive rib or feeding projection on the regulating wheel with a terminal portion on the work. Thus the work piece will be fed through even though of such smallv size that there will be no contact between the work piece and the grinding member. On the other hand, the path intermediate the feeding ribs serve to frictionally engage the work piece and to control its rotation. Thus all portions of the work piece are equally presented to the grinding member and true round work produced. ,7

It is to be understood that the taper pieces I4 shown are designed for use in roller bearings in which the final accuracy and positioning of the piece is intended to be determined by a ground portion on the periphery of the base. Therefore the surface i3 on the rib II is formed to cooperate with this portion of the base of the work piece so that the grinding of the taper will be with respect to this basal surface. If, however, for any reason it were desired to use the smaller end of the frustro-conical member for the guide the regulating wheel could be angled in the customary manner to produce a feed component urging the work axially along in the machine asheld back or limited by contact between the forward end of the work piece and the corresponding rib portion l2. The rib can therefore more properly be considered as a work positioning or feed regulating member, the two methods of employment just discussed both being clearly within the purview of the present inventive concept.

I claim:-

1. In a mechanism of the character described, the combination of a grinding wheel; a regulating wheel disposed with its periphery in proper relation to the periphery of said grinding wheel to permit the article to be ground to pass therebetween; a separation on the periphery of said regulating wheel adapted to regulate the passage of such article; and a conveyor disposed transversely of said wheels and adapted to feed successive articles therebetween.

2. A centerless grinder for producing taper work including opposed grinding and regulating members forming a'work receiving throat and a work support disposed within the throat, said support having a progressively advanceable portion movable parallel with the axis of the grinding member and having a work supporting surface disposed at an angle to its line of movement and means on the regulating wheel for advancing the work and its support.

3. A centerless grinder including opposed grinding and regulating members forming a work receiving throat therebetween and a work supporting member disposed within the throat, said work supporting member including a transversely movable portion having a supporting surface disposed at an angle to its line of movement and the regulating member having a progressively advancing tapered path movable in synchronism with the movable work support.

4. A centerless grinder including opposed grinding and regulating members forming a work receiving throat therebetween and a work supporting member disposed within the throat, said work supporting member including a transversely movable portion having a supporting surface disposed at an angle to its line of movement and the regulating member having a progressively advancing tapered path movable in synchronism with the movable work support, the angle of the taper portion of the regulating member with respect to the grinding member being double t e angle of the work supporting surface with its line of movement.

5. In a centerless grinder, the combination with opposed work grinding and regulating members forming a work receiving throat therebetween, of a work supporting member disposed within the throat, and a movable work-receiving shoe carried by the support, the regulating member having a taper surface forming a variable width grinding throat, and the shoe having an upper configuration corresponding in form to the shape of said throat but of lesser degree, substantially as illustrated.

6. A centerless grinder including opposed work grinding and regulating members forming a work receiving throat therebetween, a support disposed within the throat, a work-supporting shoe mounted on the support and movable transversely of the throat, and means on the regulating member for imparting transverse movement to the supporting shoe.

7. A precision roll grinding machine of the centerless type including a grinding wheel, a worksupport extending transversely of the periphery of the grinding wheel in juxtaposition thereto for lateral engagement with a series of work-pieces. the grinding wheel being rotatable in a direction to urge the work against the support, and a work regulating wheel at the opposite side of the worksupport having its surface adjacent the support rotatable in the opposite direction from that of the grinding wheel at a slow rate, said regulating wheel being of large diameter relative to the diameter of the work to be operated upon and having a helical guide rib of flat pitch formed peripherally thereon, whereby on rotation of the regulating wheel the work-piece will receive maximum rotation during its axial advance under propulsion of the guide rib, the surface of the regulating wheel intermediate the turns of the rib being formed in a path with a taper double that desired to be produced on the work, whereby as the work-pieces conform thereto their opposite faces will be presented in alinement with each other and parallel to the periphery of the grinding wheel for grinding action thereby, substantially as illustrated.

8. In apparatus of the character described, the combination with a bed, of a work supporting member carried thereby, a grinding wheel adjacent the work supporting memberadapted to be rotated at a relatively high speed and with its operative face moving in the direction of the work supporting member, a regulating member on the opposite side of the work support adapted to be rotated at a relatively low speed and in a direction to present an operative surface travelling in a direction opposite from that of the adjacent grinding wheel surface and adapted thereby to control the rotation of the work, means actuable by the regulating wheel on rotation thereof for presenting work to the grinding throat between the grinding and regulating wheels, and additional means operable on rotation of the regulating wheel for conveying the work through said throat.

9. A regulating wheel for use in conjunction with a centerless grinder comprising a drum member of large diameter relative to the diameter of the work to be controlled thereby, said drum having a path formed peripherally thereon in the form of an advancing helix of fiat helix angle, the path being transversely tilted at double the angle of taper to be formed on a work piece supported thereby, whereby the surface of the work piece at a point diagrammatically opposite its engagement with the surface of the path will define a line parallel with the axis of the drum, substantially as and for the purpose described.

10. A spiral feed drum for grinding machines for elongated tapered rollers having a peripheral spiral feeding groove whose base is at an angle with respect to the axis of rotation and the peripheral wall of said drum and to the axis of rotation and peripheral wall of the grinding wheel, said feeding groove being provided with pitched and wound narrow rib are formed in said groove.

11. A spiral feed drum for grinding machines for elongated tapered rollers having a peripheral spiral feeding groove whose base is at an angle with respect to the axis of rotation and peripheral wall of the grinding wheel, said feeding groove being provided with identically pitched and wound supplementary spiral groove intermediate its margins, the distance between said supplementary groove and the margin on the deeper portion of said feeding groove being less than the distance between said supplementary groove and the other margin of said feeding groove.

12. In a machine of the class described, an axially rotating spirally ribbed drum having means carried thereby and forming part thereof for removing rollers from a tube in which they are disposed end to end. a

13. A mandrel adapted to remove rollers from a tube in which they are disposed end to end, and to regulate the movement of said rollers along a work supporting trough, said mandrel comprising an axially rotating spirally ribbed drum, the end of said spiral rib nearest the tube being provided with a knife edge for separating adjacent rollers and to hold back all behind the leading one of them.

' 14. In a machine for grinding elongated, cylindrical or tapered, non-spherical rollers, a rotating grinding wheel, a rotating, feed-regulating, spiral drum adjacent said wheel, with its axis parallel to the axis of said wheel, means between said wheel and said drum and slotted to provide a trough in which said rollers move across said wheel, a feeding tube having a part axially aligned with the slot, and opening into the end of said slot and thru which the rollers are fed endwise into the latter, and .means carried by and forming part of said drum to force a roller endwise out from said tube and endwise into the drum spiral.

15. A spiral feed drum for grinding machines for elongated tapered rollers, having a peripheral spiral feeding groove whose base is at an angle with respect to the axis of rotation and the peripheral wall of said drum and to the axis of rotation and peripheral wall of the grinding wheel, said feeding groove being provided with a spiral relief groove, at its margin whereby accurate forming of the base and sides of the main groove is facilitated, the pitch and winding of the relief groove and of the feeding groove being identical.

GEORGE E. MERRYWEATHER.

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