US2351502A - Cam grinding apparatus - Google Patents

Description

June 13, 1944. c. J. GREEN 2,351,502

CAM GRINDING APPARATUS Filed Sept. 2, 1942 4 Sheets-Sheet 2 CL. HEENCEJEREEN MLJfiik-n June 13, 1944. Q J GREEN 2,351,502

CAM GRINDING APPARATUS Filed Sept. 2, 1942 4 Sheets-Sheet 4 EL HEE/VCE JER EE/V muauwmmw Patented June 13, 1944 2,351,502 cm GRINDING arraaa'ros Clarence J. Green, Worcester, Mass., asslgnor to Norton Company, Worcester, Mass, a corporation of Massaclmsett Application September 2, 1942, Serial No. 456,975

Claims.

This invention relates to grinding machines and more particularly to a cam grinding ma-' chine.

One object of thi invention is to provide a simple and thoroughly practical grinding machine for grinding cams. Another object of the invention is to provide a cam grinding apparatus in which a cam for imparting motion in two directions may be accurately ground. Another object of the invention is to provide a cam grinding apparatus in which the cam being ground is moved longitudinally and laterally to accurately produce a pre-determined cam contour. A further object of this invention is to provide a cam grinding apparatus having a rock bar which is arranged for a simultaneous rocking about in axis and moved longitudinally in an axial direction to grind a pre-determined cam contour. Other parts will b obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements. and arrangement of parts as will be exemplified in the structures 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 embodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of a grinding machine embodying this invention:

Fig. 2 is a fragmentary plan view of the grinding machine shown in Fig. 1 having parts broken away and shown in sections to clarify the illustration;

Fig. 3 is a fragmentary elevation showing the arrangement of the rock bar together with the work support and the master cams for controlling the movements thereof;

Fig. 4 is a fragmentary staggered sectional view on an enlarged scale, taken approximately on the line 4-4 of Fig. l; and

Fig. 5 is a fragmentary detailed view showing the arrangement of the rock bar.

A cam grinding machine as illustrated in the drawings comprising a base I0 which serves as a support for a longitudinally traversable table II. The table II is supported on a V-way l2 and a flat way l3 formed on the upper surface of the base Ill. The table II is arranged so that it may be traversed longitudinally along the base III by means of a manually operable traversing mechanism comprising a hand wheel 14 which is supported on the outer end of a shaft ii. .A gear l6 is mounted on the inner end of the shaft I5 and 55 meshes with a gear l'l mounted on a rotatable shaft I! which is Journaled in suitable bearings (not shown) in the base end. The shaft II also supports a gear I! which meshes with a rackbar depending from the under side of the table I I.

A stop mechanism is provided for locating the table II in a pre-determined fixed position for a grinding operation. The stop lug is fixedly mounted on the base l0 and is arranged to be engaged by a pair of adjustable stop dogs 26 and 21. The stop dogs 26 and 21 are supported by T-slot 28 formed in the front edge of the table II. The stop dogs 26 and 21 are each provided with an adjustable stop screw 29 and 30 respectively by means of which the table I I may be precisely located to position the work piece to be ground in a pre-determined position with relation to the grinding wheel.

The base II) also serves as a support for a transversely movable wheel slide 32 which is arranged to slide transversely relative to the base 10 on a V-way 33 and a flat way 34. The wheel slide 32 supports a rotatable wheel spindle 35 in journal bearings (not shown). A grinding wheel 36 is mounted on one end of the wheel spindle 35 and a driving pulley 31 is mounted on the other end thereof. The driving pulley 31 is connected by a driving belt 38 with a suitable source of power, such as, for example an electric motor (not shown) mounted on the upper surface of the wheel slide 32.

A wheel feeding mechanism is provided for moving the grinding wheel 38 transversely comprising a rotatable feed screw 40 which is supported in the bearing (not shown) in the base ID. A half nut 4| depends from the under side of the wheel slide 32 and meshes with the feed screw 40. The feed screw 40 is provided with an integral reduced cylindrical portion 42 which projects from the front of the machine base. A gear 43 i mounted on the outer end of the feed screw shaft 42 which in turn meshes with a gear 44. The gear 44 is mounted on the inner end of a rotatable shaft 45. A manually operable feed wheel 46 is mounted on the outer end of the shaft 45. A micrometer feed adjusting mechanism 41 is provided with a stop abutment 43 which is arranged to engage a pivotally mounted stop pawl 49 which is in turn pivotally supported in the front of the machine base ill. It will be readily apparent from the foregoing disclosure that by a manual manipulation of the feed wheel 46, the grinding wheel 36 may be moved transversely either toward or from the work supporting table II as desired. By adjustment of the micrometer trunnions II and I2 feed adjustment 1, the grinding wheel Il may bemovedintoaprecisepositiontogrindthe work piece to the desired diameter. For further details of this feeding mechanism reference may be had to the expired U. 8. Patent to C. H. Norton No. 762,838 dated June 14, 1904,

The work supporting table II serves as ampport for a rock bar IO. The rock bar ll is provided at its opposite ends with a pair of axially aligned trunnions BI and I! which are journaled in bearings formed within the brackets l3 and N projecting upwardly from the work table I I. The rockbar II is arrangedsothat itmayberocked about the trunnions II and I! and is also arranged so that it may be moved longitudinally: that is in an axial direction with respect to the bearing rotation of a work piece to impart a combined transverse and longitudinal movement to a work piece being ground in a manner to be hereinafter described.

The rock bar I. is provided with a rotatable head stock or master cam spindle 5! which is journaled in upwardly projecting brackets N and 51 which are formed integral with the rock bar II. The spindle 55 is provided with a work center is which engage and supports one end of a work piece 59 to be ground. A rootstock Cl is adjustably supported on the rock bar 50 and is provided with a footstock center 6| which engages and supports the opposite end of the work piece 5". The headstock spindle I is also provided with a face Plate I having a driving pin 63 which is arranged to drivingly engage a work dog 84 mounted on/or adjacent to the left hand end of the work piece ll. The headstock or master cam spindle I5 is provided with a master cam 85 which is arranged toengage a master cam roller 8.. The master cam' roller '6 is supported on a rotatable shaft 01 which is in turn rotatably journaled in bearings (not shown) in the brackets I and II which are formed integral with the brackets I! and 51 respectively.

A motor drive is provided for the headstock or master cam spindle 55 comprising an electric motor III which drives through a gear reduction unit contained within the casing H to rotate a universal joint 12 which connects with the left hand end of the spindle 55 (Fig. 2). It will .be readily apparent from the foregoing disclosure that a rotary motion of the master cam or headstock spindle 55 will transmit a rotary motion to the workpiece 59. At the same time a rotary motion is imparted to the master cam 65 which is yieldably maintained in operative contact with the roller 68 so that the motion of the cam 65 will impart a rocking motion to the rock bar It and thus cause the axis of the work piece I! to move towards and from the periphery of the grinding wheel 36 to generate a pre-determined contour on the work piece 59 being ground.

In order to grind special cam shapes having both a transverse as well as an axial movement to be imparted thereby, a suitable mechanism is provided to simultaneously impart an axial movement to the rock bar ill during its oscillation. This mechanism may comprise a master cam 15 having a face cam generated thereon. A master cam roller is provided and is rotatably supported on a shaft I1 which is supported within a casing or frame II surrounding the headstock of the machine. A compression spring III is interposed between a flanged plate ll fastened to the bracket 54 at one end and a collar 82 adjustably connected by a rod 03 with the exertsapressuretendingtomcvetherockbar in a direction toward the right (Figs. 1, 2, 3) so as to maintain the operative side face of the cam II in operative engagement with the master cam roller ll.

In order that the master cam roller ll may be maintained in a pre-determined relationship with the cam ll during the transverse oscillation of rock bar II, the shaft I1 is preferably supported trunnion 52 in a manner so that the spring 8| 7 by two pairs of rollers II and I! and 81 at one end and '8, IO, and I. at the other end. The shaft 11 thus supported is free to move in a transverse direction. In order that the shaft may move in timed relation with the rock bar 50, a strap ll surrounds a portion of the master cam or headstock spindle II. The strap ll connects by a stud I! with the end 01 the shaft 11. It will .be readily apparent from the foregoing disclosure that when the rock bar II is oscillated about its pivotal axis by means of the cam BI and follower It, the strap II being rotatably supported on the spindle II will move the master cam roller I8 transversely so as to maintain it in a pre-determined relationship with the operative face of the cam ll. During the rotary motion of the spindle II to impart a transverse oscillation of the rock bar I, the cam I! will in turn impart a simultaneous longitudinal movement to the rock bar so that a cam face having the surfaces Ill and III to be ground may be accurately generated as desired. In order to maintain the master cam II in operativeengagement with the master cam roll-' er II a tension spring Ill is contained within a casing Ill supported by a bracket Ill on the end of the headstock casing 18 (Fig. 2). The upper end of the spring I02 is connected to the lower end of an adjusting screw I. The lower end of the adjusting screw is connected to a stud ll! which is pivotally supported by a stud I carried by a bracket Ill. The bracket I01 is in turn pivotally connected by a stud I" with an arm III! which is formed integral, with the rock bar 50. The right hand face oi the casing I03 is open (Fig. 1) so that as the rock bar is moved in an axial or longitudinal direction by the cam II, due to the pivotal connection at the lower end of the spring Ill a constant tension will be exerted .by the spring III uniformly to maintain the master cam ll in operative contact with its follower roller I. v v

The operation of this improved cam grinding apparatus will be readily appreciated from the foregoing disclosure. Assuming all of the parts to have been previously setup, a work piece Is having cam faces I00 and Ill to be generated is mounted in position on the work supporting centers 58 and ii respectively with the work driving pin is in engagement with the work driving dog 64. The table Ii is then traversed longitudinally so that the work piece II is in a desired and pre-determined relationship with the grinding wheel ll after which the table. dogs 20 and 21 are locked in adjusted position. The table may then be precisely adjusted to afurther extent by manipulation of the stop screws 20 will generate the cam faces I and "H which are arranged to transmit transverse and longitudinal movements. Wheel may be fed transversely to grind the faces I00 and IM to the desired and pro-determined extent by a manual manipulation of the feed wheel 48.

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.

Iclaim:

1. In a cam grinding apparatus having a transversely movable rotatable grinding wheel, a rotatable work supporting member including a rotatable spindle, means positively to rotate said spindle, a longitudinally and transversely movable support for said work supporting member, means including a cam on said spindle and a follower to impart a transverse movement to said work supporting member, independent means including a second cam on said spindle and a second follower simultaneously to impart a longitudinal movement to said work supporting member to facilitate grinding an irregular cam face, a transversely movable support for said second follower, and means to maintain said latfer follower in a predetermined relationship with said second cam during transverse movement of said longitudinally and transversely movable support.

2. In a cam grinding machine having a transversely movable rotatable grinding wheel, a rock bar which is pivotally supported about an axis parallel to the axis of the grinding wheel, a rotatable work support on said bar including a rotatable master cam spindle and a footstock, means including an electric motor to rotate said spindle and work piece, means including a master cam on said spindle and a follower to impart a transverse rocking movement to said bar, means including a second master cam on said spindle and a slidably mounted follower roller which are arranged to impart a longitudinal axial movement to the rock bar, said cams being shaped and timed to impart a combined simultaneous longitudinal and transverse movement to generate an irregular cam face, a transversely movable support for said slidably mounted follower roller, and means to maintain said follower in a predetermined relationship with said second cam during oscillation of said rock bar.

3. In a cam grinding apparatus having a base, a transversely movable rotatable wheel thereon, a longitudinally movable work table on said base, means to locate and hold said table in a predemined grinding position, a rock bar pivotally supported on said table, a rotatable work support on said rock bar including a rotatable spinnections between said slide and said spindle whereby said latter follower is maintained in a predetermined relationship with said latter cam during oscillation of said rock bar.

4. In a cam grinding apparatus having a base, a transversely movable rotatable grinding wheel thereon, a longitudinally movable work table on said base, means to locate and hold said table in a predetermined grinding position, a longitudi-* nally movable rock bar pivotally supported on said table, a rotatable work support on said rock bar including a rotatable spindle to support and rotate a work support, means positively to rotate said spindle, means including a cam on said spindle and a follower to impart a rocking movement to said bar, yieldable means to maintain said cam in operative engagement with the fol-. lower, means including a cam on said spindle and a follower simultaneously to impart a longitudinal movement to said rock bar to facilitate grinding an irregular cam face on a work piece, a transversely movable slide supporting said second follower, and connections between said spindle and slide to facilitate maintaining said second follower in a predetermined relationship with the second cam during the rocking movement of said bar.

5. In a cam grinding apparatus having a base, a transversely movable rotatable grinding wheel thereon, a longitudinally movable work table on said base, means to locate and hold said table in a predetermined grinding position, a longitudinally movable rock bar pivotally supported on said table, a rotatable work support on said rock bar including a rotatable spindle to support and rotate a work support, means positively to rotate said spindle, means including a cam on said spindle and a follower to impart a rocking movement to said bar, yieldable means to maintain said cam in operative engagement with the follower, means including a second cam on said spindle and a second follower simultaneously to impart a longitudinal movement to said rock bar, yieldable means to move said rock bar longitudinally in one direction to maintain said second cam in operative contact with its follower, a transversely movable slide supporting said second follower, and connections between said spindle and slide to facilitate maintaining said second follower in a predetermined relationship with the second cam during the rocking movement of said bar.

CLARENCE J. GREEN-

Images