US2220768A - Cylindrical grinding machine - Google Patents

Description

CYLINDRICAL @BINDING MACHINE Filed March 9, 1938 y 2 Sheets-Sheet l Hexbex S. 'Indge' www Gttorneg -CYLINDRICAL GMNDING MACHINE Filed March 9, 1938 2 Sheets-Sheet 2 lll rwentor Qxbev SQnge.

. E! Lb E l Gttomeg Patented Nov. 5, 1940 CYLINDRICAL Gnmnmemaonmn Herbert s. man, wenn, mimorm Norton Company, Worcester, Mm.. a corporaj` tion of Massachusetts Application March 9. massaal No. isms?. s emma (ci :s1-95) 'I'his invention relates to grinding and lapping machines, and more particularly to a machine for grinding or lapping cylindrical surfaces' of work pieces, such as rolls used in rolling mills and the like.

One object of the invention is to provide a simple and thoroughly practical grinding machine \in which the axes of the grinding wheel and the work are arranged at an angle to each other so that thewheel and the work engage each other in a helical line of contact.4 It is another object of the invention to provide a cylindrical grinding or lapping machine with a wheel mount which is arranged so that, the wheel spindle lies in a plane parallelto the work axis but at an angle relative to the work axis and in which the periphery of the wheel is formed with a concave operating face which wraps around a portion of the periphery of the work piece and contacts therewith in a helical path. Other objects will be in part obvious or in part pointed out in the following disclosure.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of a grinding machine embodying the invention;

Fig. 2 is a fragmentary cross sectional viw through the grinding machine shown in Fig. l, showing the cross feed mechanism;

Fig. 3 is a fragmentary cross sectional view, showing the manual table traverse mechanism;

Fig. 4 is a front elevation of a modified construction in which the wheel axis is adjustable angularly in a plane parallel to the work axis; and

Fig. 5 is a fragmentary view of a truing apparatus.

A grinding machine has been illustrated in the.

drawings comprising a base III` which supports a transversely movable wheel slide I I on a V-way I2 and a flat way I3 for a transverse feeding movement relativefto the base. 'I'he wheel slide II supports a rotatable wheel spindle Il havingl a grinding wheel I5 mounted on one end thereof. A driving pulley'IB is'provided to transmit power from any suitable source, such as an electric motor on the wh/eel slide or an overhead belt drive (not shown). The lbase I0 also supports alongi-'j tudinally reciprocable work supporting table 20 which is arranged to slide longitudinally on V- Way 2| and a flat way 22. The table 20 is provided with a/headstock 24 and a footstock 25 which serve rotatably to support a work piece 26 in operative'posmon with reiuon'io the ernia-f ingwheel. A The wheel slide II isarrangedvtovbe fed transversely relative to the-base I0 by means of a.

cross feed mechanismforfexam ple such-as that shown in the 'prior United States patent to Nort0n No. 762,838 dated June 14, 1904, tovwhicl'iv reference mayk be had for details of disclosure.

Such afeeding mechanism may consistofahalf nut 28 depending. fromV the `wheel slide-II which meshes with a rotatable feed screw 2ljournaledin bearings (not shown) in- -the-.basey III.I The feed screw 29 has an integral shaft 30 extending toward the front of the machine. The frontend of the feed screw'shaft Mis provided with a gear Il meshing with a .pinion 32 whicliis supported f on the inner end of a rotatable shaft-$3. The. front end of a shaft 32 is provided-with ya manv'im feed screw and thereby cause vthegrinding wheel i ually operable feed wheel lLwhich maybe rotated in either direction to vcause a rotation of the to move either toward or from the vworin-as desired. l

The work table 20 may reciprocated longitudinally relative to the base. I0 either :manually or by power. For the sakeof simplicity ofA illustration, a power reciprocatingmechanismfor the--v table has beenV indicated, anda manually operal ble traversemechanism has beenshownin detail. The work'table 20is providedwith a depending. rack 38 whichI meshes with a. gear 38 mounted. on l the inner end of a transverselyextending rotatable lshaft'. 40 which is-Journaled in the base II).

The front end of the shaft I0' is providedwith a gear" which meshes with asmall gear-4 2 mounted on the inner end of a rotatable shaft 43. The

outer end of the shaft 43 is provided with` a.

manually operable traverse wheel M byrotation' of which the table 20 may be traversed either toward the right or toward the left', dependingy upon the direction of rotation of the hand wheel The work table 20 may be'movedlongitudinally by means of a power actuated tablereciprocatlng mechanism. such as that yshown in theyprior patent to Norton above `referred to.. Such a power operated reciprocating mechanism has been indicated langs.; and 4 of the drawings,

showing a housing ilwhich en closesl a variable speed/power driven mechanism to .rotatea transversegshaft 5Iv which operates through afftable= reversing mechanism, 52 tol reciprocate'the table 20 longitudinally. to thedeslred-extent. A pivotally mounted reversing lever 5 5 isarranged' to bek engaged by adjustable table dogs't and 51 to change the direction of movement of vthe table after it has traversed'a vpredetermined distance in either direction. 'By manipulation of vthe variable speed power driving mechanism, .the

table may be reciprocated longitudinallyduring the rotation of the work support and at such a speed that for a given wheel width the work makes one complete rotation while'the table is traversing substantially one wheel width. The 5 details of disclosure of the power reciprocating and reversing mechanism have not been illustrated, since they are not considered to be part of the present, invention. For details ofdisclosure of this mechanism, reference may be had to the above-mentioned prior patent to Norton No. 762,83 8.

In previous cylindrical grinding operations, the grinding wheel has been arranged so that the wheel and work axes are parallel to each other, so that the grinding wheel presents a peripheral surface formed as a true cylinder of revolution which in grinding contacts with the work along an element of the periphery of the cylindrical work piece. With such an arrangement of parts, any irregularities in the grinding wheel or in the surface being ground cause vibrations to be set up and due to the fact that a line contact is made between the wheel and work. The vibrations of the Wheel or work cause chatter marks to be produced on the periphery of the work piece. Furthermore, in such a grinding operation, due to the arrangement of the grinding wheel and work, there is a tendency to produce feed lines on the finished surface. It is the main object of this invention to eliminate these difficulties and to provide a construction in which the grinding wheel spindle I4 lies in a plane parallel to the axis of rotation of the work piece V26 but is tilted at an angle thereto so that when the grinding wheel is trued in position on the machine, it presents a concave operating surface which engages and wraps around the work surface and contacts therewith in a helical line of contact. When the work and wheel are rotated in operative relation with each other in this position of the parts, any irregularities in the surface of the wheel or work make points of contact only with the operative face of the wheel and due to the fact that the wheel wraps around a por- 45 tion of the work piece, there is no vibration set up in the grinding operation, thus eliminating chatter marks. The angle of tilt of the wheel spindle I4 relative to the wheel axis preferably bears a definite relation with the table traverse 50 movement, namely such that when the table is traversed by power the face of the wheel will grind a helical path on the periphery of the roll or cylindrical work piece being ground.

Heretofore where the axes of the wheel and 55 work piece have been parallel to each other, there has been a tendency to produce grain marks in a substantially circular path around the work piece due to the fact that the rotation of the individual grains in the periphery of the 60 grinding Wheel is at substantially right angles to the axis of rotation thereof. In the improved construction illustrated in Fig. 1, the angle of the wheel spindle is such that the grains travel in a path at substantially right angles to the 65 helical path produced by the wheel as the work table is traversed longitudinally, that is, the active face of the wheel will move across the work piece in a direction inclined with respect to the axis thereof, thus spanning the high and low points of the chatter marks and feed lines, so as to eliminate not only chatter marks due to irregularities but also grain markings and produce a fine finish on the periphery of the work piece being ground.

It may be desirable in certain grinding operations to provide a suitable adjustment for the wheel axis, so that the angular position of the wheel may be varied in accordance with the type and size of work being ground. Figure 4 ofthe drawings shows a modified construction in which a grinding wheel 'I0 is mounted on a horizontal spindle II which is journaled in a wheel supporting frame 12. A swivel connection is provided between the wheel mounting 'I2 and a transversely movable wheel slide '14. By means of locks nuts 'I5 and 16, the wheel mount 12 may be unclamped from the slide 'I4 and adjusted angularly to vary the position of the axis of the wheel spindle II relative to the axis of the work piece 26. The wheel slide 'I4 is arranged so that it may be adjusted transversely by means of a manually operable hand wheel 'I'I. 'I'he wheel 'I1 may be connected to move the slide 'I4 transversely in any suitable manner such as, for example, as shown in the prior patent to Norton No. 1,108,779 dated August 25, 1914. 'I'he transversely movable wheel slide I4 is supported on a vertically movable slide 80 which is arranged to be adjusted vertically on a column 8| by means of 4a manually operable hand wheel 82 which serves to rotate a nut relative t`o a vertical screw 83 to position the vertical slide 80 and thereby adjust the position of the wheel relative to the work axis.

In order that the grinding wheel may be accurately trued to present a concave operative surface which engages the work on a helical line of contact, it is desirable to true the wheel by utilizing a grinding wheel 90 which is of Va diameter equal to the diameter of the work being ground. The truing wheel 90 is preferably mounted on a spindle 9i which may be supported ona headstock center 92 and a footstock center 93 so that the truing wheel may be rotated by the headstock 24 while it is reciprocated past the grinding wheel I5 or the grinding wheel 'I0 while they are in a skewed relation with the work axis. The truing wheel is mounted on centers and the work table 20 is reciprocated to traverse the truing grinding wheel I5 or 10 While the wheels I5 or 10 are fed toward the truing wheel so as to true the operative face thereof to the desired extent. By truing the grinding wheel in this manner, an operative face is produced which will engage wheel 90 relative to the l the work periphery on a helical line of contact for grinding the cylindrical work piece.

The operation of this mechanism is readily apparent from the foregoing disclosure. The wheel spindle I4 is set at a fixed angle (Figs. 1 and 2) relative to the axis of the roll being ground and the periphery of the Wheel is trued to a concave shape by mounting a diamond or truing wheel 9D (Fig. 5) on the work table and traversing the table to pass the truing tool across the face of the grinding wheel. 'Ihe work piece 26 is then mounted on the machine and rotated by means of a headstock 24 while the table 20 is reciprocated longitudinally relative to the base I0 by means of the power operated feed mechanism indicated by the parts 5U, 5I and 52 to cause the work to travel longitudinally while the concave peripheral surface of the wheel Wraps around a portion of the wheel periphery engaging the work on a helical line of contact and grinds in a helical path without vibration to produce a rened cylindrical surface free from chatter marks and substantially free from grain markings and feed lines caused by the wheel.

In the modified' construction, asy illustrated in ing a diamond or truing apparatus on the work table 20 and traversing the table 20 to pass the truing tool across the periphery of the wheel. The work piece may then be inserted in the machine and the manually operable hand wheel 82 rotated to feed the wheel into operative engagement with the work piece 26. The work table 2O may then be traversed with the Wheel wrapping around a portion of the work periphery and engaging the surface thereof in a helical line of contact and grinding in a helical path to, produce a refined cylindrical surface.

It will thus be seen that there has been provided by this invention apparatus i'n which the various objects hereinabove set forth together with many thoroughly practical advantages are successively achieved. As many possible embodiments may be made of the above invention and as many changes might be made in' the embodiment above set forth, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

l. A cylindrical grinding machine comprising a base, a longitudinally movable table thereon, a rotatable work support including a head and footstock on said table rotatably to support a work piece, a rotatable grinding wheel, means continuously to rotate said work support and to reciprocate said table longitudinally so that the longitudinal movement of the table and the rotation of the work supportare so related that for a given wheel width the work makes a complete rotation while the table is traveling substantially one wheel width, a transversely movable wheel slide on said base, and a rotatable wheel spindle for said grinding wheel which is supported in bearings on said slide and arranged in a plane parallel to the axis of-the Work piece but skewed at an acute angle thereto, said grinding wheel having a concave operative face which is arranged to engage the periphery of the continuously rotated work piece in a helical path.

2. A cylindrical grinding machine comprising a base having a rotatable Work support and a rotatable grinding Wheel thereon, said grinding wheel having a concave operative face, a longitudinally traversable table carrying one of said parts which is movable longitudinally relative to the base, a transversely movable slide carrying one of said parts which is movable transversely relative to the table, means continuously to rotete said work support and to reciprocate said fable longitudinally so that the longitudinal movement of the table and the rotation of the work support are so related that the work support makes one complete rotation while the table travels less than one wheel width, and a rotatable wheel spindle for supporting said grinding wheel so that its axis lies in a plane parallel to the axis of rotation of the Work but at an acute angle thereto so that the concave operative face of the grinding wheel wraps around and engages the peripheral surface of the continuously rotated Work piece in a helical path so that the active face of said grinding wheel moves across the work piece in a direction inclined with respect to the axis thereof.

3. A cylindrical grinding machine comprising a base having a rotatable grinding wheel having,

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a concave peripheral operative face, a slide carrying said grinding wheel, a longitudinally movable work table, a rotatable work support on said table which is arranged rotatably to support a cylindrical work piece, means to reciprocate said table longitudinally, means continuously to rotate said work support, said work rotation and table reciprocation being such that the work rotates one complete rotation while the table travels less than one wheel width, means to move the grinding wheel slide toward and from the work piece, and means to tilt the axis of said grinding wheel relative to the axis of the work piece so that the concave peripheral grinding face is arranged to wrap around and engage the periphery of the cylindricalA continuously rotated work piece in a helical line of'contact and is arranged so that the active face of the grinding wheel travels across the work piece being ground in a direction inclined with respect to the axis thereof. l

4. A cylindrical grinding machine comprising a base, a longitudinally movable work supporting table slidable longitudinally thereon, a rotatable work support on said table rotatably to support a work piece, a rotatable grinding wheel having a concave peripheral operative face, means continuously to rotate said work support and to. reciprocate said table longitudinally so that the Work makes one complete rotation While the table travels substantially one wheel Width or less, a wheel slide to support said wheel which is movabletransversely relative to said base, a tiltable support for said wheel slide arranged to enable adjustment of the wheel axis relative to the axis of the work so that the concave'operative face which engages the periphery of the workpiece in a helical line of contact is arranged so that the active face of the grinding.

wheel travels across the work piece being ground in a direction inclined with respect to the axis thereof.

5. A cylindrical grinding machine comprising a base, a, longitudinally movable work supporting table slidable longitudinally thereon, a rotatable work support on said table rotatably to support a work piece, a rotatable grinding wheel having a concave operative surface, means continuously to rotate said work support and to reciprocate said'table longitudinally at suitable rates so that the work support rotates`one complete rotation while the table travels lsubstantially one Wheel width or less, a wheel slide to support said wheel which is movable transversely relative to said base, a tiltable support for said Wheel slide which is arranged -to enable adjustment of the wheel axis relative to the axis of the work so that an element of the concave operative face of the grinding wheel engages the periphery of the work piece in a helical line of soy contact, and the active face of said wheel moves

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