US2189931A

US2189931A - Grinding machine

Info

Publication number: US2189931A
Application number: US253152A
Authority: US
Inventors: Stubbs Everard
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1939-01-27
Filing date: 1939-01-27
Publication date: 1940-02-13
Anticipated expiration: 1957-02-13

Description

Feb. 13, i940. E. sTUBBs @99933 GRINDING MACHINE Filed Jan. 27, 1939 5 Sheets-Sheet 1 Fuz-'.1

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GRINDING MACHINE Filed Jan. 2v, 1959 s sheets-sheet s vb vn me/wwe EvERHRD ETUBBS Patented Feb. 13, im

GRINDING MACHINE lvenxd Stubbs, Springfleld, Vt., asslgnor to Norton Company, Worcester, Mass.. a corporatbn of Massachusetts i 1939, Serial No. 253,152

Application January 27 9 Claims.

The invention relates to grinding machines, and more particularly to a grinding machine adapted to finish a Work piece having an irregular contour.

One object of the invention is to provide a simple and .thoroughly practical grinding apparatus for grinding an irregular object, such as a cam or eccentric or isodiametric objects. Another object of the invention is to provide an improved grinding machine in which the Work support is moved transversely toward and from the grinding wheel in a straight line motion as controlled by a cam and a follower. A further object of the invention is to provide a grinding machine having a transversely movable headstock and a transversely movable footstock each of which is independently moved transversely by means of a pair of synchronously rotated master cams and followers. Other objects will be in part obvious or in part pointed out hereinafter.

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. l is a front elevation of an improved grind- `ing machine embodying this invention, having parts of the base broken away more clearly to show the operating construction;

Fig. 2 is a left-hand end elevation, on an enlarged scale, of the footstock and the master cam and follower for controlling the same;

Fig. 3 is a right-hand end elevation, on an enlarged scale, of the headstock mechanism;

Fig. 4 is a vertical sectional view through the headstock, taken approximately on the line 4--4 of Fig. 3;

Fig. 5 is a fragmentary horizontal sectional view, on an enlarged scale, taken approximately on the line 5-5 of Fig. 2; and

Fig. 6 is a sectional view, on an enlarged scale, taken approximately on the line 6 6 of Fig. 5,

showing the cross sectional view through the work piece.

The improved grinding machine as illustrated in the embodiment may comprise a base I0 which supports a longitudinally reciprocable work supporting table II on the usual V-way and fiat way (not shown) for a longitudinal reciprocatory movement relative to the base I0. A headstock I2 is mounted on the table Il and serves as a driving means for a rotatable work supporting mechanism to be hereinafter described.

A rotatable grinding wheel I3 is supported on a transversely movable wheel slide I4 which is mounted to slide transversely relative to the base lll in a manner'similar to that which is old and well known in the art, as shownffor example, in the U. S. patent to Norton No. 762,838 dated June 14, 1904, to which reference may be had for details of disclosure not contained herein. In the preferred form, an electric motor I5 is mounted on the upper surface of the wheel slide I4.` The motor I5 is provided with a driving pulley I8 which is connected by a driving belt l1 with a pulley I8 mounted on the outer end of the grinding wheel spindle (not shown). As illustrated in Fig. 1, the wheel spindle driving belt I1 above described is contained within a belt guard or housing I9.

A fluid pressure mechanism is provided to reciprocate the table II. In the form illustrated, a cylinder is xedly mounted to the under side of the table Il. 'Ihe cylinder 25 contains a pair of spaced pistons (not shown) which are connected by a pair of hollow piston rods 26 and 21, respectively, with a pair of

hollow brackets

28 and 29, respectively, which are flxedly mounted on opposite ends of the base I0. The table operating or reciprocating mechanism, as indicated in Fig. 1, is substantially identical to that shown in the prior United States patent to Wallace H. Wood No. 2,071,677 dated February 23, 1937, to which reference may be had for details of disclosure not contained herein.

A table operated reversing lever 30 is pivotally mounted on a stud 3l on the base I0 and is con-l nected in a manner shown in the above-men tioned Wood patent to operate a control valve (not shown) to reverse the direction of movement of the table II. The lever 30 is actuated by a pair of

table dogs

32 and 33 which are ad-a justably positioned in a Tslot 34 mounted in the' front edge of the table II A manually operable lever 38 is pivotally mounted on a bracket 39 and is connected through a knob 40 and valve stem (not shown) to operate a throttle valve (not shown) which also serves as a stop and start valve. This valve together with the table reversing valve is identical with that shown in the above-mentioned prior patent to Wood and consequently has not been illustrated in detail in the present case since it is not considered to be a part of the present invention.

The table II may also be moved manually by means of a manually operable table traverse mechanism comprising a manually operable rotatable hand wheel which is rotatably supported relative to the base I0. The hand wheel 45 serves to rotate a gear 46 meshing with a gear 41. A gear 48 is arranged to rotate with the gear 41 and meshes with a rack bar 49 which is in turn flxedly mounted to the under side of the table Il.

In order to produce a desired and predetermined feed of the grinding wheel, a manually 50 operable feeding mechanism is provided comprising amanually operable feed wheel 55 which carries a small gear 58 meshing with a gear 51 mounted on the outer end of `a rotatable feed screw shaft 58. The feed screw shaft 58 is provided with a feed screw threaded portion projecting under the wheel slide I4 and meshing with a half nut (not shown) depending from the under side of the wheel slide I4, in a manner such I as that ,shown in the above-mentioned prior patent to Norton.

The feed wheel 55 may be manually rotated to cause a transverse movement of the wheel either toward or from the work piece to be ground, if desired. The grinding wheel I3 may also be fed automatically and intermittently at the ends of the reciprocatory stroke of the table II by means of a wheel feeding pawl 59 which is pivotally mounted on a stud 60. The stud 50 is carried by a vertically movable reciprocable slide 6| which is reciprocated by a fluid pressure motor contained within the housing 82. feeding motor is identical with that shown in the above-mentioned prior .patent to Wood No. 2,071,677 and consequently has not been illustrated in detail herein. Reference may be had to the above-mentioned patent for details of disclosure not found herein.

Rotatable work holder As illustrated in Figs. 5 and 6 of the drawings, a work piece 10 of iso-diametric cross section, such as is disclosed in my prior U. S. Patent No. 1,912,412 dated June 6, 1933, is supported on a headstock center 1| and a footstock center 12.

`A cam attachment headstock bracket 13 is clamped in position on the table II by means of a clamping stud 14 and a clamping block 15. A footstock supporting frame 16 is clamped in position on the table by a clamping stud 11 and a clamping block 18.

The headstock bracket 13 is provided with an integral upwardly extending portion 80 which is hollow and is provided with a transversely movable slide 8|. The slide 8| is supported on anti-friction bearings comprising four spaced lines or rows of

anti-friction rollers

82, 83, 84 and 85 (Fig. 4). Alternate rollers in each of the rows are arranged with their axes at right angles to each other so as to facilitate free movement of the slide 8| to precisely control the transverse movement of the headstock work supporting center 1| and thereby control the contour of the work piece 10 being ground. The slide 8| is provided with a spindle 86 which supports the headstock center 1|. A face plate 81 is rotatably supported on a bearing 88 which rotates on the spindle 86. The face plate 81 is provided with spaced lugs 89 and 90 (Fig. 3) each of which is provided with a set screw to engage a work piece driving dog which is fastened to the end of the work piece 10 in a manner similar to that employed in camshaft and cylindrical grinding operations.

This cam grinding apparatus is particularly arranged and adapted for use as an attachment which may be readily applied to a standard cylindrical grinding machine. To facilitate rotation of the work piece, a rotatable headstock face plate supported by the grinding machine headstock I2 carries a sprocket |0| which is connected by means of a driving link chain |02 with a sprocket |03 which is keyed to a rotatable shaft |04. The shaft |04 is rotatably supported in a bracket pivotally supported on a stud or shaft This |08 which is carried by the projection 80 of the headstock attachment 13. The bracket |05 is pivotally mounted to facilitate taking up slack in the driving chain |02 and also in a driving chain to be hereinafter described. An adjusting screw |01 is screw threaded into the projection 80 of the headstock frame 13 and its head bearsv against the under side of the bracket |05 and serves to facilitate adjustment of the bracket |05. A lock nut |08 serves to lock the screw |01 in adjusted position.

A sprocket |09 which is keyed to the shaft |04 is connected by means of a link driving chain I0 with a sprocket III which is keyed to a rotatable sleeve ||2. The sleeve ||2 is rotatably supported in a bushing I|3 mounted in the transversely movable slide 8|. A small gear or pinion |I4 is keyed to a left-hand reduced end portion of the sleeve I|2. The pinion or gear ||4 meshes with a larger gear I|5l which is flxedly mounted to rotate the face plate 81 and thereby transmit a rotary motion to the work piece 10. The gear |I5 is preferably formed as a split gear having a second part IIS which may be adjusted relative to the gear I I5 so as to facilitate taking up backlash between the gear ||5 and the sprockets ||4.

In order to transmit a transverse movement of the slide 8| and the work piece 10 to produce a predetermined contour on a work piece to be ground, a cam actuated mechanism is provided including a master cam |20 which is keyed to the outer end of the sleeve I2. The master cam |20 is held in position against any endwise movement by means of a collar |2|. This collar I2| may be readily removed when desired to facilitate replacement of the master cam |20 for a similar cam of a different shape for producing a differently shaped work piece. A follower |22 is mounted on the fixed part of the frame 80 by means of a pair of clamping studs or screws |23 and |24 which pass through an elongated slot |25 in the follower |24 and are screw threaded into the frame 80. An adjusting screw |26 serves as a backing and adjusting screw and also serves to facilitate adjustment of the follower |22 in a transverse direction. It will be readily apparent from the foregoing disclosure that when the headstock face plate |00 is rotated, a rotary mction will be transmitted through the chain drive above described to rotate the sprocket and the sleeve I|2 and thereby rotate the attachment face plate spindle 81 and the work piece 10. When the sleeve ||2 is rotated, it also serves to rotate the master cam |20 which in turn cooperates with the follower and causes a transverse movement of the slide 8| and the work piece 10.

In order to facilitate the master cam |20 remaining at all times in operative engagement with the follower |22 so that the cam will produce the desired transverse movement of-the slide 8|, a stud |30 is screw threaded into the slide 8| and passes through a clearance aperture in the frame 80 and extends into an enlarged hole |3| within the projecting boss |32 of the frame 80. A compression spring I33 surrounds the stud |30 and is interposed between a headlon the stud |30 and the bottom of the enlarged hole |3|.` This spring has suflicentcompression so that the cam |20 is at all times maintained in operative engagement with the follower |22.

In order to attain one of the main objects of the invention, it is desirable that the footstock center 12 be moved transversely in synchronism with the headstock center 1| so that the work piece may be ground throughout its length to master cam the desired and predetermined contour. The footstock center 12 is supported in a slidably mounted footstock sleeve |40 which is in turn supported in a transversely movable slide I4I. 'Ihe slide |4I is arranged tov slide transversely relative to a frame |42 formed integral with the i'ootstock frame 16. An adjusting screw |43 is provided which serves as a stop to limit the movement of the footstock center toward the left. A compression spring |44 serves normally to hold the footstock center in operative engagement with the work piece. The footstock spindle |40 is arranged so that it may' be rapidly withdrawn to facilitate loading of work pieces into the machine by means of an actuating handle |45 which is mounted on the upper end of a rotatable shaft |46. |46 which meshes with rack teeth |48 formed on the periphery of the spindle |40. By rotation of the gear segment |41 (Fig. 5) in a clockwise direction, the iootstock center 12 and the spindle |40 may be moved toward the right to withdraw the center from operative engagement with the work piece 10.

The footstock slide I4| supports a rotatable sleeve |50 which in turn supports on its outer end a master cam I5I. The master cam I5| is accurately timed to rotate in synchronism with the master cam |20. The master cam |5| is accurately timed to rotate in synchronism with the |20. This is preferably accomplished by means of a multiple splined shaft |53. The splined shaft |53 has a left-hand end reduced diameter portion |54 which is slidably keyed within an aperture in the sleeve I I2 and is held in longitudinal adjusted position relative to the sleeve ||2 by means of a screw |55. The right-hand end of the multiple splined shaft |53 passes through a`multiple splined aperture within the rotatable sleeve |50 so that rotation of the sleeve |I2 rotates sleeve |50 synchronously therewith, thus synchronizing the rotation of the master cams 20 and |50, and the transverse movement of the opposite ends of the work piece 10.

The master cam |5| is held in adjusted position on the sleeve |50 by means of the collars |56 and |51. The master cam |5| is accurately timed relative to the master cam |20 so that both cams are arranged to synchronously move the slides 8| and |4| toward and from the grinding wheel I3 to produce a desired and predetermined contour throughout the length of the work piece 10.

As illustrated in Fig. 5 of the drawings, a three to one reduction is provided between the work drive face plate 81 and the sleeve ||2 so that the sleeve ||2 rotates three times while the face plate 81 and the work piece 10 rotate once. The work piece 10 as illustrated is commonly known as a tri-lobe shaft, as shown in A gear segment |41 is mounted on the shaft,

cross section in Fig. 6, and it is only necessary to produce one-third of the shape on the cam |20. Thus the contour ofthe cam |20 and the cam |5| causes the'slides 8| and |4| respectively to move toward and from the wheel axis three times during one rotation of the work piece 10 and consequently produce three portions of the work of the same identical shape.

As illustrated in the drawings. the grinding apparatus is set up for grinding a shaft having a triangularly shaped cross section (Fig. 5) which ds known as a tri-lobe shaft. This shaft has three projecting lobes which fit within a correspondingly shaped aperture and serve to replace the commonly used multiple splined shaft. By utilizing a three to one reduction in the drive betweenrthe sleeve ||2 and the work driving face plate 81, a master cam |20 may be utilized which is shaped to produce only one lobe on the shaft. Due to the three to one reduction, the master cam |20 rotates three times to a single rotation of the faceplate 81 and work piece 10. By Autilizing such a construction, it is easier to produce a master cam formed accurately to produce a single lobe and inasmuch as the same cam surface produces each lobe on the shaft. three identically shaped lobes will be accurately produced. Similarly the master cam I5I, which is synchronously rotated with the master cam |20, produces a synchronous movement of the footstock center 12 so that both ends of the shaft are synchronously moved toward and from the grinding wheel to facilitate grinding a shaft having an identical cross section from end to end. The cam |5I is shaped exactly to correspond with the master cam I 20 and is accurately timed therewith. p

While the illustration in the drawings shows a three to one reduction for producing a tri-lobe shaft, this reduction may be readily varied to meet the needs of the particular grinding job. The master cams |20 and |5I are readily removable so that they may be replaced by cams of different contours to produce other shapes on a work piece. The multiple splined shaft |53 may be readily withdrawn by removing the screw |55, and the gears ||4, ||5 and ||6 may be readily changed so that' a one to one relation may be obtained or any desired gear reduction may be obtained between the sleeve supporting the master cams and the work supporting and rotating members.

The operation of this improved grinding apparatus will be readily apparent from the foregoing disclosure. `Assuming all of the parts to have been previously adjusted. and the proper master cams I 20 and I5| mounted in place and the desired gear ratio provided between the driving sleeve ||2 and the work drive face plate 81. the footstock center 'I2 is withdrawn by manual operation of the lever |45 and a work piece 10 is inserted between the headstock center 1| and the footstock center 12.4 The grinding wheel may then be set in rotation and the rotation of the work started through the headstock |2 and the table traversed or reciprocated, either manually or by power, as above described. As the work piece 10 rotates in operative contact with the grinding wheel, the mastercams |20 and |5| produce a synchronous horizontal transverse movement of the slides 8| and I4| toward and from the wheel axis soas to generate a predetermined contour on the periphery of the work piece 10. The grinding operation proceeds until the shaft ANl has been ground to the required predetermined size and contour.

While this machine has been shown as set up for grinding a tri-lobe shaft, it is'equally applicable to grinding irregularly shaped objects. such as eccentrics, cams and the like.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully 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 hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in -a limiting sense.

I claim:

l. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said grinding wheel transversely, a longitudinally movable table, a rotatable work support thereon including independent transversely movable headstock and footstock centers, and means including a cam and a follower synchronously to move said centers transversely toward and from the grinding wheel to grind a predetermined contour on the work piece.

2. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said wheel transversely, a longitudinally movable table, a rotatable work support thereon including a headstock and a footstock center, spaced independent transversely movable slides on said table to support said headstock and footstock centers, and means including a cam and a -follower synchronously to move said slides to produce a transverse movement of said centers to grind a predetermined contour on the work piece.

3. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said wheel transversely, a longitudinally movable work table, a rotatable work support thereon including a headstock and a footstock center, a pair of spaced independent transversely movable slides to support said headstock and footstock centers, and anindependent cam and follower to move each of said slides transversely to grind a work piece to a predetermined contour.

4. A grinding machine having a rotatable transversely movable grinding wheel, means t0 feed said wheelv transversely, a longitudinally movable table, a rotatable work support including a headstock and a footstock center, spaced independent horizontally movable slides on said tableto support said headstock and footstock centers, a master cam and a follower associated with each of said slides which are arranged to move said slides transversely toward and from the grinding wheel, and means synchronously to actuate said cam simultaneously to move said headstock and footstock centers toward and from the grin'ding wheel periphery to grind a work piece to a predetermined contour.

5. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said wheel transversely, a longitudinally movable table a rotatable work support including a headstock and a footstock center, spaced l independent horizontally movable slides on said table to support said headstock and footstock centers, a master cam and a follower to move said headstock center toward and from the grinding wheel, a second master cam and follower to move said footstock center toward and from the grinding wheel, and a driving mechanism synchroand a transversely movable footstock on said table, headstock and footstock centers supported thereon, a rotatable master cam and a follower to move said headstock transversely toward and from the grinding wheel, a rotatable master cam and a follower to move said footstock transversely toward and from the grinding wheel, and means synchronously to rotate said master cams simultaneously to move the headstock and footstock toward and from the grinding wheel periphery to generate a predetermined form thereon.

7. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said wheel transversely, a longitudinally movable table, a rotatable work support including a transversely movable headstock and a transversely movable footstock thereon, a rotatable work' drive face plate on said headstock,

vspaced independent rotatable master cams and followers to move said headstock and footstock transversely, a driving shaft between said mastransversely movable grinding wheel, means to f feed said wheel transversely, a longitudinally movable table, a rotatable work support including a transversely movable headstock and a transversely movable footstock thereon, a rotatable work drive face plate on said headstock, spaced independent rotatable master cams and followers to move said headstock and footstock transversely, a driving shaft between said master cams synchronously to rotate said cams, means to rotate said driving shaft, and reduction gearing between the driving shaft and the headstock face plate to rotate the work drive face plate at aV slower speed so that the master cam rotates a plurality of rotationswhile the face plate rotates once so that a single lobed master cam produces a multiple lobed ground surface.

9. A grinding machine having a rotatable transversely movable grinding wheel, means to feed said wheel transversely, a longitudinally movable table, a rotatable work support including va transversely movable headstock and a transversely movable footstock thereon, a rotatable work drive face plate on said headstock, spaced independent rotatable master cams and followers to move said headstock and footstock transversely, a driving shaft between said master cams synchronously to rotate said cams, means to rotate said driving shaft, and reduction gearing between said shaft and headstock face plate synchronously to rotate the face plate once while the shaft and master cams rotate three times so that a single lobed master cam produces a trilobed ground surface.

EVERARD STUBBS.