US2059895A

US2059895A - Grinding machine

Info

Publication number: US2059895A
Application number: US566738A
Authority: US
Inventors: Charles H Norton; Albert G Belden
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1931-10-03
Filing date: 1931-10-03
Publication date: 1936-11-03
Anticipated expiration: 1953-11-03

Description

Noy. 3, 1936. c. H. NORTON ET AL GRINDING MACHINE Original Filed Oct. 3, 1951 4 Sheets-Sheet 1.

CHHRLES H. Nome/v ALBERT" G. BELDEN W/TNESS Nov. 3, 1936. c. H. NORTON ET AL GRINDING MACHINE 1931 4 Sheets-Sheet 2 Original Filed Oct. 5

CHARLES H. NoRro/v IqLBEIET G. BELDEN GRINDING MACHINE 4 Sheet-Sheet 3 Original Filed Oct. 3, 1931 e a m MN v cu m r R0 n 0 L 0;. N B m H. 0 6 n 1 0n n M m u H8 m i u m E h cu z 5 .I M Q n n I r Wis N T1 5 1 M l m H z w Nov. 3, 1936.

c. H. NORTON ET AL.

GRINDING MACHINE 4 Sheets-Sheet 4 Original Filed Oct. 5, 1931 HHHHHH H o N H m L m H C Patented Nov. 3, 1936 UNITED STATES GRINDING MACHINE Charles H. Norton, Plainville, Conn, and Albert G. Belden, Worcester, Mass., assignors to Norton Company, Worcester, Mass.. a corporation of Massachusetts Application October 3,

1931, Serial No. 566,738

Renewed February 24, 1936 24 Claims.

This invention relates to grinding machines and particularly to a machine adapted for grinding round work to a predetermined size.

Owing to keen competition and the present day demands for rapid production of duplicate, accurately shaped, cylindrical work pieces, a large percentage of the machining of such work involves the use of automatic machinery which must be capable of rapidly finishing successive work pieces within exceedingly narrow limits of accuracy and producing exactly the required finish upon each piece of work. Many of the work pieces subjected to a precision grinding operation, such as roller bearings and the like, com- 16 prise short cylindrical pieces which require being ground throughout their entire length by a wide ,wheel. To support and rotate work pieces of this type for a precision grinding operation has heretofore presented various problems which have been met largely. by two types of grinding machines. Qne type involves what is commonly known as the .centerless principle, wherein the work piece is ground between a rapidly rotating grinding wheel and a slowly rotating speed'regulating wheel, the work being supported upon a fixed support between the two wheels. However,

a centerless machine of this type has been found unsuitable for continuously grinding within the narrow limits of accuracy necessary for various 30 types of work, and particularly work which must have its cylindrical surface concentric with its axis. A further inherent difliculty in such a machine is its tendency to produce chatter marks upon the work surface owing to vibration within 35 the machine and the non-uniform rotation of the work piece between the two abrasive wheels.

Also, it has been found impracticable to remove a large amount of stock with a single pass of the work through the machine. 1

It has further been contemplated to perform a grinding operation by the so-called one wheel centerless method wherein the work is peripherally supported in a dovetailed channel of a guide bar while it is simultaneously rotated, moved axially and ground by means of a grinding wheel. In many instances, this type of grinding has proved unsatisfactory, due to the fact that the rotative action of the rapidly rotated wheel 50 against the work periphery produced an uneven work rotation whichresulted in producing flat portions or other defects on thework surface. In such a grindingoperation, the work is not rotated positively and uniformly and it is. not 55 supported properly; hence there is a tendency for inaccuracies in the work contour to be produced and amplified during grinding.

Another machine which has been utilized to grind this type of work is of the type shown in the prior patent of Norton, No. 1,779,779, wherein 5 the work is mounted on centering hubs and positively rotated by an end pressure gripping mechanism while the grinding wheel is fed through a predeterminedcyclic movement to grind the work to required size.

It has been found that if a work piece of an irregular shape is peripherally supported .by a work steadying shoe having a concave surface of a radius of curvature equal to that of the desired finished work piece and if the work axis is permitted to move freely while the work is being positively rotated within the shoe, the grinding operation will proceed through a progressive series of approximations until the work is reduced to a cylindrical surface which mates with the curved surface of the work supporting shoe and has a radius of curvature equal to that of the shoe. During this operation, the grinding wheel and work will, of course, be fed relatively towards each other to produce the necessary removal of stock from the work piece.

It is therefore, one object of this invention to utilize this theory of grinding and to provide a grinding machine operated either manually or automatically, which is especially adapted for grinding a Work piece rapidly and accurately to a required cylindrical surface.

A further object of this invention is to provide a precision grinding machine of this type wherein the work is positively ground by means of a grind- 5 ing wheel fed relatively towards the work to a predetermined position to produce a desired cylin drical work size, and wherein the work is peripherally supported substantially throughout its entire length against the thrust of the grinding wheel and rotated by positively acting work rotating mechanism which does not serve to support the work.

It is a further object to provide a grinding machine of this type wherein successive work pieces may be mechanically fed to and from the work supporting member in correct timed relation to the grinding cycle and with a minimum loss of time. Further objects will be apparent in the following disclosure.

In accordance with our invention, we propose to support a rotating work piece against the grinding wheel thrust by means of a work supporting and steadying member engaging the peripheral surface of the work and to feed the grinding 55 wheel and the rotating work relatively towards each other to grind the peripheral surface to a desired size. This steadying member preferably comprises one or more shoes having a partial cylindrical surface, or elements thereof, which has the radius of the finished work piece and so fits or mates with the peripheral work surface when the latter has been ground to its correct final size, thereby aiding in perfecting the work surface- The rate of the work rotation is governed by a positively driven device which is independent of the work supporting and grinding members. This device preferably comprises members gripping against the ends of the work piece or non-' supportably engaging the same at points remote from the surface being ground. The wheel and the work are preferably rotated in the same direction at the point of tangency and the parts are so coordinated and arranged that any rotative impulse imparted by the wheel to the work is utilized and controlled, whereby the driving mech- 'anism may serve with small effort to insure a positive and controlled work rotation. In a machine embodying these features, provision is made whereby, as the work decreases in size and its axis moves radially in the support, the positively driven rotating members which govern the work rotation will maintain efiicient driving contact with the work without being required to support it and maintain its axis in a given position. For this purpose we may employ a universal driving connection engaging the work at a position remote from the surface being ground, although various other means for rotating the work positively may be employed.

As hereinafter explained, these various features which are applicable to a simple manually operated machine may also be embodied in a machine operated automatically, wholly or in part, for grinding a plurality of work pieces to duplicate size and shape. In the embodiment of our machine as illustrated, the work steadying member is adapted to receive the work from a suitable supply and to have the work automatically removed therefrom upon completion of the grinding cycle. The machine illustrated utilizes a hopper or other feeding device arranged to present work pieces successively to the work steadying and supporting member, and this may be easily accomplished by so locating the various machine parts that the work steadying member may be moved away from the grinding wheel to receive a work piece from the feeding device and then moved toward the grinding wheel to present the work piece in the grinding zone. The finished work pieces may be removed either manually or automatically from the work supporting member just prior to its receiving a fresh work blank for presentation to the grinding wheel.

This invention has been illustrated as applied to a grinding machine embodying variousautomatic features set forth in the prior patent to Charles H. Norton, No. 1,779,779 wherein the grinding wheel is automatically fed into the work by a cam controlled cross feed mechanism and the work rotation is eifected by a mechanism operating in timed relation therewith.

-In these drawings, in which like reference numerals indicate like 'parts:

Figure 1 is a fragmentary perspective view illustrating diagrammatically the arrangement of wheel, work, steadying support and driving mechanism involved in a machine embodying this invention;

Figure 2 is a diagrammatic view showing how a work blank is ground to ultimately conform to the exact curvature of the steadyrest shoe;

Figure 3 is a diagrammatic perspective view showing the operative parts of an automatic machine embodying this invention;

Figure 4 shows a front elevation of one particular embodiment" of our invention, which is partly broken away to better illustrate the operating mechanism; V Figure 5 shows an end elevation of the work loading device with a work piece supported in the steadyrest shoe in grinding position; Figure 6 is a fragmentary rear elevation showing a work piece supported by the steadyrest in grinding position and engaged by the work rotating mechanism;

Figure 7 is a fragmentary end elevation of the work receiving and supporting mechanism in retracted position to receive a fresh work blank prior to a grinding operation;

Figure 8 is a similar fragmentary view showing a work piece being discharged from the steadyrest shoe upon completion of the grinding operation;

Figure 9 is a fragmentary sectional view taken approximately along the line 9-9 of Figure 5;

Figure 10 is a sectional view through the control valve taken along the line l0l 0 of Figure 4;

Figure 11 is a sectional view through the control v'alve showing the relative piston and port positions; and

Figure 12 is a sectional view taken along the line I 2-l 2 of Figure 11 showing the throttled exhaust fluid control.

In explanation of the principles underlying our invention, reference is to be had to Figs. 1 and 2 of the accompanying drawings, wherein a work blank W is shown as peripherally supported in grinding position substantially throughout its entire length by a steadyrest shoe H) which is provided with a concave arcuate work supporting surface of such curvature that it will exactly mate with the finished cylindrical work surface as shown in Figure 2. Since the work blank W is peripherally supported for rotation within the steadyrest shoe I0, it has been found advisable to cut away part of the concave supporting surface, thereby providing two supporting surfaces l2 and I3, having the same axis and forming parts of the same cylindrical surface, to minimize the friction between the work and the steadyrest shoe and still provide ample work support for an accurate grinding operation.

The work may be engaged for rotation within said steadyrest by any suitable mechanism, which in the present instance comprises two axially slidable, spring supported heads l4 and I5 arranged to simultaneously and frictionally engage the end faces of the work and positively rotate it without offering any support thereto. In

other words, the workrotating mechanism must be so'arranged that it will positively rotate the work piece W during a grindingoperation caused by a rotatably driven grinding wheel l6, which may be moved relatively towards and from the steadyrest shoe III to grind the work, but the thrust of the grinding wh'eel must be wholly received by the work supporting shoe irrespective of the type of work rotating device employed. The work and the wheel are preferably rotated in the same direction at the point of contact, as indicated by the arrows in Fig. 2, so that the wheel tends to aid in the work rotation. As shown by the dotted and full circles in Fig. 2, the 'work at first rides onthe outer portions of the shoes,

but gradually approaches the final position of mating with the shoe surfaces when the correct size has been attained. It will be noted that since this work blank prior to grinding does not seat within the accurately finished concave supporting surfaces l2 and I3 but only engages them at two extreme points, any roughness upon the periphery of the work blank prior to grinding would not engage these accurately finished surfaces I2 and I3 and create injury thereto.

This new. method of grinding has been applied to an automatic grinding machine, one embodiment of which is illustrated diagrammatically in Fig. 3 and in detail in the remaining figures. This machine comprises a base 25 arranged to carry a wheel slide 21 adapted to move transversely on said base on the V-way 29 and fiat way 38 thereby causing the grinding wheel l6 rotatablysupported on a spindle journaled within the wheel slide, to approach or recede from the grinding zone. The grinding wheel may be rotated by any suitable means such as shown in the prior United States Patent to Charles H. Norton #l,779,'779.

Work supporting mechanism One of the principal features of this invention involves the provision of a work supporting shoe or steadyrest III as previously described. To properly support saidsteadyrest member, a bed 32 is firmly but adjustably secured to the forward portion of the base 25 in front of the grinding wheel by bolts 33. and nuts 34 screwed thereon. The bed 32 is provided with fiat ways 36 and dovetailed ways 31 which serve to slidably support a member 39 so that it may be moved towards and from the grinding wheel in a direction parallel to the wheel slide movement. A gib 40 is provided at one side of the dovetailed ways and may be adjustably positioned by screws 42 locked in position by nuts 43 to frictionally engage the slidable member 39 and take up any lost motion between member 39 and its support as it moves within the ways 31. The'slidable member 39 is further provided with a fiat top surface 45 within which is tapped a threaded hole 46 adapted to receive a cap screw 41 which passes through a support member 48 seated upon fiat surface 45 and serves to vertically pivot member 48 on member 39. To angularly locate support member 48 relative to member 38 about the cap screw 41, the support member 48 is provided with a'rearwardly extending portion 50 which is clamped between the screws 5| and 52 threaded respectively into two

lugs

53 and 54 projecting from the top of member 39 as shown in Fig. 9.

To look the screws 5| and 52 in fixed adjustment, lock nuts 55 and 56 are provided which are respectively threaded thereon. The support member 48 is provided with an arcuate concave top surface 58 adapted to support a block 60 having an arcuate convex surface shaped to mate with the surface 58. Block 60 is adjustably and angularly secured to member 48 about a horizontal axis by cap screws 64'and set screws 65 whereby the respective convex and concave surfaces maybe slid upon each other to angularly position block 60. The forward portion of block 60' isarranged to receive and rigidly support the steadyrest shoe 10 which serves to peripherally support each work piece during its grinding operation as shown in Figs. 1, 2, 3 and 5.

To produce an accurate grinding operation so thatthe work will be ground to the same diameter throughout its entire length, the axis of each piece of ground work mustnecessarily be aligned to lie parallel with the grinding wheel axis. Thus the steadyrest axis may be adjusted to lie within a horizontal plane by adjusting screws 64 and 55 and the steadyrest axis may then be brought par- 5 allel with the wheel axis by adjusting screws 5| and 52 and locking them in position by means of lock nuts 55 and 56. Further adjustments may be provided as desired.

Wo'rk gripping and rotating mechanism Another important feature of this invention involves-the provision of a work gripping and rotating mechanism which serves to yieldingly engage the work and rotate it while it is sup- 15 movement of the work center as the grinding operation causes a reduction in work size. In the present instance we utilize rotatable gripping members frictionally engageable with each end of the work, and a positively actuated power driven mechanism to retract the gripping members from the work in timed relation with the grinding cycle, In order to make the work gripping and rotating device most effective; it is essential that the work gripping heads, such as the heads l4 and I5 shown in Fig. 1, engage both ends of the workpiece W close to its periphery so that the torque and the engaging friction may be maintained as high as possible as compared to the rotating effect of the grinding wheel upon the work. It is also essential that the work gripping heads be of a smaller diameter than the finished work piece since in the present machine the grinding wheel I6 is of sufficient width to grind the entire work surface in a single plunge out grinding operation. If the work were to be gripped near its axis there might be slippage causing an uneven work rotation resulting in fiat spots on the work and a consequent imperfect grinding action.

In the preferred construction of our automatic to the wheel rotation so that the work surface travels in the same direction at the point of grinding, whereby the grinding wheel may assist in driving the work. This spindle rotation is 1 accomplished by pulleys 69 and I9 slidably mounted upon the'spindles 61 and 68 and respec tively driven by belts l4 and 15 from a pair of pulleys 15 and I1 fixed to a drive shaft 19 gear connected to a main drive shaft, as disclosed in the prior patent to Norton $1 1,779,779.

The work gripping means may comprise two heads 82 and 83 afilxed to the inner end of the spindles 61 and 68 and frictionally engaging the work as shown in Fig. 6 so that there will-be no 6 tendency for the'work rotating mechanism to center and support the workduring its rotation.

However, our preferred type of work gripping head is shownin Fig. 1 wherein the heads l4 and I5 are secured to the spindles 61 and 68 by means of

springs

85 and 86 respectively which in the present instance have been welded at each end to the spindles and respective work gripping heads. These springs permit the center lines of the work and the driving spindles to be out of alignment to a slight extent as required by a change in size of the work. This particular construction minimizes any tendency to center and support the work by the rotating means and has, therefore, allowed the work to be wholly supported by the steadyrest shoe I during the work rotation and yet to be driven positively as it moves farther into the steadyrest. Whatever the type of work gripping head utilized, it has been found advisable to recess the end of each head which grips the work so that said head may engage the work with an annular face adjacent to the work periphery as illustrated by the surface 08 upon head I in Fig. 1. Due to the fact that the ends of the work may be covered with an oil film, it has also been found advisable to knurl the work gripping surfaces.

The axial movement of the spindles to automatically grip the work during the,grinding cycle and thereafter releases it in timed relation to receive a fresh work blank is similar to-the construction as shown in the prior patent to Norton #l,' 79,7'79, wherein the spindles 6'! and 60 are moved by levers 80 and 9| pivoted to the machine base by studs'82 and 83 respectively.

The upper ends of these levers are provided with yoked portions 35 and 36 connected to engage collars 81 and 88 afiixed to the respective spindles 81 and 88, whereby any movement of levers 80 and 8| will cause a corresponding axial spindle movement toward or from the ends of the work. The lever 3| is shaped like a bell crank andis provided with'a downwardly extending portion I00 connected by a pivot pinto a connecting rod IOI. In order to move the two

levers

90 and 9| simultaneously toward or from each other, the lower arm of lever 30 is provided witha single gear tooth projection I03 engaging with the mating projection I04 of abell crank lever I05 pivoted to the base of the machine by a stud I06. Lever I05 is provided with 9. depending arm IIO which is 'pivotaliy connected to the rod IOI. A further and substantially horizontal arm III is providedon bell crank lever I05 and serves to pivotally support a depending adjustable weight II2 therefrom. This mechanism as illustrated in Figs. 3 and 4 is so arranged that the pull of weight II2 normally acts to force the work engaging heads towards each other to grip the opposite ends of a work piece W with an equalized pressure during the work rotation.

To automatically separate the work driving heads from the work and release the finished work upon completion of a grinding cycle, and permit a new work piece to be placed in the grinding zone for engagement with the; driving heads, an ad-- Justable positively actuated intermittent mechanism, is provided to act in timedrelation with an automatic wheel feed. This is accomplished in a similar-manner as shown in the patent to Norton #1,779,'l'79 wherein a slowly revolving member acting in timed relation to the grinding feed is arranged to strike the lower end of one of the spindle actuating levers and force it and the parts associated therewith to retract the work gripping heads at the proper time in the work grinding cycle.

As illustrated in Figs. 3 and 4, a roller H5 is rotatably mounted upon a stud I I6 secured at one A end of an adjustable arm I I0 rotatably mounted at its pposite end upon a camshaft 9. A projecting arm I 201s fixedly mounted upon thecamshaft III and is'provided" at its outer end with an adjustable engaging screw I22, the outer end of which engages arm 8 and causes it to. rotate with shaft H3. It will thus beseen that any adjustment of screw I22 will angularly position arm II8 relative to other operating mechanisms affixed to camshaft H9. The connecting rod MI is provided with a head I25 at its end adjacent to the camshaft II9, said head being pivoted by means of a stud I 26 to the lower end of lever arm I00.

The head I25 carries a depending, adjustable arm I28 pivoted thereto by means of a pin I30 and angularly adjustable by means of an arcuate slot I34, the side faces of which may be securely engaged by a nut I threaded upon stud I 26 to lockthe depending arm I28 in correct angular position. The lowerportion of depending arm I28 is provided with a surface I3'I which, due to the adjustment of arm I28, may be so positioned that it is in the path of roller II 5. As the camshaft I I8 rotates, the adjusting screw I22 forces the roller arm 8 and roller II5 about its axis with shaft H9 and the roller II5 strikes the surface I3'I on arm I28 swinging the linkage mechanism toward the left thus moving the

yoke portions

95 and 96 outwardly and causing the work gripping heads to simultaneously withdraw from the end faces of the work piece W.

To prevent a rapid dropping of the weight I I2 and consequently a too sudden motion of the spindles 61 and 88 im gripping a new work blank after roller I I5 has left surface I31, we preferably mount weight II2 so that its lower portion acts as a dash pot system as shown in Fig. 3. The piston or weight H2 is surrounded by a dash pot cylinder I40 which is provided with an opening to the atmosphere controlled by an adjustable air valve I42 so arranged that a controlled leakage 'of air may serve to cushion as well as retard the downward motion of weight I I2. By varying the weight I I2 and adjusting air valve I42, the spindies 61 and 68 may be moved slowly or rapidly towards each other to grip the work and rotate it during grinding.

The bottom of the dash pot I40 is provided with a series of perforations or holes I 43 to let air rapidly flll the cylinder as piston H2 is lifted so that the work gripping heads may be quickly disengaged from the ends of the work. To prevent any air from escaping through holes I 43 during the downward movement of piston II2, a soft- Cross feed mechanism This machine also provides for an automatic cyclic wheel feed mechanism which causes the grinding wheel to feed toward the steadyrest shoe for a predetermined distance and then upon completion of the grinding operation to withdraw therefromj said feed operating in precise timed relation to the. other operative features of 'the machine. Tofaccomplish this, the grinding wheel is rotatably mounted within a cross slide which has a feed screw connected thereto in the usual manner. The feed screw is automatically rotated by a power operated mechanism and the rate of rotation and direction of movement is accurately regulated by another automatic device preferably'a cam, so that the wheel may be fed forward a predetermined extent and then withwithdraw the wheel and reset the weight for the next infeed of the wheel. The length of the feeding stroke may be varied without changing the cam by connecting said cam with the feed screw by means of a chain passing over a sprocket on the screw shaft and adjustably connecting one end of the chain to a lever which is rocked by the cam.

This cross slide mechanism is preferably patterned similar to the construction shown in the prior patents to Norton Nos. 762,838 and 1,443,924 wherein a halfnut I50 is secured to a depending portion upon the under side of the wheel slide 21 which is screw threaded to engage corresponding threads upon a feed screw I52. The feed screw which is rotatably journaled in the base of the machine has a gear I53 secured to its forward plunger I68 from an opening I69 in the index plate I10 afiixed to the arm I62, the crank arm I65 may be revolved the required amount to adjust arm I62 relative to the gear wheel I63. This construction makes it convenient to position the grinding wheel as desired relative to the work as well as to make necessary adjustments to compensate for the wheel wear and it even makes it 0 possible to feed the wheel by hand whenever de sired.

Cam controlled power drive for feed screw The feed screw is preferably rotated by a cam controlled mechanism utilizing a cam and a follower operatively connected to the feed screw, and so arranged that the distance and rate of travel of the wheel into and away from the work are dependent upon the contour of the cam. This is best accomplished by mounting a cam I14 upon camshaft H9 in fixedangular relation to arm I20 also fixed on said shaft. To positively rotate the cam I14 at the required rate a worm I16 is mountedupon a shaft I11 journaled within the base and said worm is maintained constantly shaft I19 (Fig. 4).. Shaft I19 also is provided with a gear IflI affixed thereon which in tummeshes with an intermediate gear I82 arranged to drive a gear I63 keyed onthe camshaft II9 to rotate arm I20 and cam I14 as shown in Figs. 3 and 4 and also in the Patent to Norton #l,779,'779. Power is applied from any suitable source to rotate the shaft I11, such as is shown in said patcut, and the power may be engaged or disengaged to operate the machine by means of a clutch I controlled by an operating lever I15 on the front of the machine as is shown in Fig. 4.

To translate the motion of the cam I14 so that the wheel feed movement may be accurately regulated, a lever I89 (Figs. 3 and 4) is mounted upon a pivot I65 secured within the base. The short arm I86 or lever I84 is provided with a yoke portion which rotatably supports a roller I88 upon a pin I89 so that the roller may always engage the operative surface of cam I14. To transmit the cam motion from lever I 84, a chain I94 is utilizedfl This chain passes over a sprocket I95 amxed to one end of a sleeve I96 which is rotatably mounted upon shaft I55 and has the gear wheel I63 afllxed to its end. The lever I84 is provided with an upstanding arm I98 which is so shaped that the upper end of chain I94 may be adjustably secured thereto by a slidable clamping member I99. The lower end of chain I94 is connected by a weight 202, which is slidably mounted within a guard 203 upon the front of the machine. This weight is of sufiicient size to turn sprocket I95 and the associated mechanism causing a rotation of the feed screw I52 to feed the grinding wheel into the work and always maintainthe follower roll I88 in firm contact with the face of cam I14. The cam I14 is so shaped that asassume an initial rapid feed toward the work until the wheel is about to contact therewith and thereafter feed the wheel into the work slowly until the work has been reduced approximately to the correct size.

. During. the final grinding stage the feed mechanism is preferably held'immovable for a short period of time by means of an adjustable stop device 204 such as shown in the patent to Norton, #l,779,7'79 to permit the grinding wheel to complete the, grinding operation and spark out.

Thereafter a further movement of the cam serves to rapidly remove the wheel from the work during which time the finished work piece may be ejected Adjustment of the feeding stroke Although the feeding motion is necessarily lim ited by the contour of the cam the'extent of feed per cycle may be varied. To accomplish this, the

.upper arm I98 of lever I84 is made involute shaped as shown in Figs. 3 and 4. Thus by altering the position of the slidable clamping .member I99 along the arm I98 the effective length of lever arm I98 may be changed with a corre-- sponding variation upon the feeding movement of the grinding wheel. Thus the nearer that the clamping member I99 is slid toward the pivot pin I along lever arm I98 the less will be the extent for wheel feed and vice versa. To set up the.

feed mechanism for a particular piece of work would be accomplished identically as described in the Patent #1,779,7'79.

Magazine feed and work presenting mechanism Our invention further contemplates an automatic feeding mechanism whereby work blanks may besuccessively presented within the gr'indflxed thereon which in turn supports a magazine 288 adapted to hold a multiplicity of work blanks W and individually. feed them into the grinding zone. An anvil member 2I8 secured to the block 88 adjacent to and in the rear of steadyrest shoe I8 is provided with a work supporting face 2" which lies under the mouth of the magazine 288 and prevents work from being fed into the machine during the grinding operation as shown in Figs. 3 and 5.

To feed a single work piece from the magazine 288 into the steadyrest-shoe l8 so that it will be peripherally supported thereby during grinding, means are provided which automatically retract the steadyrest shoe from the grinding zone until it lies directly under the mouth of the magazine 208 as shown in Fig. 7. This is easily accomplished by a fluid pressure mechanism, which in the present instance constitutes a pneumatically operated piston and cylinder device operated in cyclic timed relation to the wheel feed by means of afluid pressure valve actuated by a cam upon the same shaft which carries the wheel feed cam. A cylinder 2l5 is clamped to the bed 32 and has a piston 2|8 slidably mounted therein. A piston rod H8 is secured to the piston at one end and to member 39 at the other end as shown in Figs. 3, 5 and 9. Thus it will be seen that any movement of piston 2|6 within the cylinder 2 l5 will be transmitted through piston rod 2i8 to' move member 89 within its supporting ways 38 and 31, thereby causing the steadyrest shoe I 8 to move through a corresponding distance towards or from the grinding zone.

A coil spring 228 is mounted upon piston rod 2l8 within cylinder H5 and under compression between a cylinder head and the piston thereby tending to force the piston 2l6 towards the rear of the cylinder and the steadyrest shoe away from the grinding zone to a position where it may receive a work piece as shown in Fig. 7. A vent 222 is provided at the forward. end of the cylinder 2 I8 50 that no air may be trapped within the forward end of the cylinder and thereby hinder the action oi the spring tending to move the piston.

The rear cylinder head is provided with a port 224 connected with a port 225 in a control valve 221 by a pipe line 228. It will thus be seen that fluid pressure controlled by the valve 221 and passing into cylinder 2l5 through port 224 will serve to move-piston H8 and compress spring 228 until the piston engages an abutment 238 at which position the steadyrest shoe III has moved into the grinding zone as shown in Fig. 5. When the fluid pressure is withdrawn from port 224 the spring 228 serves to move piston 2l8 to its rearward position which may be adjustably located by means of a stop screw 232 and lock nut 233 in the rear cylinder head (Fig. 5), at which position the piston acting through piston rod 2" and other associated parts has served to withdraw the steadyrest shoe l8 irom grinding position to a position directly under the mouth of magazine 288 to-receive a fresh work blank prior to a grinding operation as. shown in Fig; 7.

The fluid pressure control valve 221 in the present instancepneumatioally controls the operation of piston M8 to feed successive work blocks from the magazine to grinding position in timed relation to the cyclic wheel feed and the periodically operated work gripping mechanism. This is accomplished by operating said control valve by a cam 235 affixed to the camshaft .I I9

and actlngin precise timed relation to the movement of the feed cam I14 and the arm I20 which act to time the operation of the work gripping and rotating device. The cam 235 is secured to camshait H9 in proper angular relation to feed cam I14. The valve 221 is secured to the base of the machine in such a position that cam 235 will periodically engage a roller 238 operatively connected with'said valve.

The valve 221 is preferably of the familiar balanced piston type wherein two spaced

pistons

238 and 239 are slidably mounted within a cylinder 248 and connected to a piston rod 242 having the roller 238 rotatably aillxed at its lower end by means of a pin 243. A coil spring 245 is mounted upon piston rod 242 under compression against the lower head oi. cylinder 248 and a member 246 carrying the roller 238, whereby

pistons

238 and 238 will be maintained at the lower end of cylinder 240 except when roller 236 is engaged by the high point of cam 235. To adjust the positions of

pistons

238 and 239 within the valve cylinder, piston rod 242 has been threaded at its lower end and is screwed into member 246 the desired amount and locked in position by means of lock nut 248 as shown in Fig. 10.

To operate piston 2| 6 and the associated work presenting mechanism, fluid under pressure (in the present instance compressed air, although oil could easily be utilized by providing a supply tank and pump and piping the exhaust fluid back thereto) is passed through pipe 250, check valve L pipe 252 and through port 254 into the chamber 255 between

pistons

238 and 239. When the pistons are at the lower end 01. the valve cylinder 240, that is when the roller 236 is not acted upon by the high point of cam 235, fluid under pressure is free to pass out of chamber 255 through port225, pipe 228 and through port 224 into the rear of cylinder 2| 5 to move piston M6 and consequently move the steadyrest into the grinding zone, thereby presenting a work blank in grinding position. Whenever the roller 236 is engaged by the high point of cam 235, the

pistons

238 and 239 have been moved to the respective dotted line positions indicated in Figs. 3 and 11 at which position piston 238 has been moved up to cover port 254 and eifectively shut off the flow of fluid pressure into cylinder 2I5. During the time port 254 is closed the spring 220 within the cylinder 2| 5 will act to move the piston 2l8 toward the rear of the cylinder and the fluid therein will exhaust through port 224, pipe 228, port 225 into chamber 255 and out into the atmosphere through an exhaust port 251 which has been uncoveredby the upward movement of piston 239 (Figs. 3, 10 and 12). d

To cause piston M8 to move back slowly and withdraw the steadyrest shoe from the grinding zone at a desired rate, a screw 258 may be arranged to adjustably throttle exhaust port 251 and thereby cause the rear of cylinder 2l8 to act as a dash pot and retard the action of spring 228. When screw 258 has been adjusted, it may be conveniently locked in position by means of a lock nut 259. It will, of course, be apparent that port 251 is closed by piston 239 during the flow oi fluid pressure toward cylinder H8 and as a consequence only acts in the exhaust circuit.

When the piston 2 i8 is in its rearward position and the steadyrest is receiving a fresh work blank from the magazine as shown in Fig. 7, two spring supported, pivotally mounted arms 262 and 263 serve to catch the work and cushion its fall so that it may not mar the accurate work supporting surfaces l2 and I3. These arms are pivotally mounted upon the opposite side faces of member 205 so that as a work blank falls from the mouth of the magazine its ends will be caught by two similar recessed arcuate portions in the arms 262 and 263, one of which recesses 265, is shown in arm 262 as illustrated, in Figs. 5, '1 and 8. A screw 261 serves to pivotally support arm 262. A lug 210 projects from the side face of member 206 adjacent to arm 262 and directly above projecting portion 21I upon the arm 262. A screw 212 is threaded through lug 210 so that it may adjustably engage projection 2H and thereby limit the upward movement of arm 262 about pivot 261. A spring 213 affixed to member 205 at one end and pressing against the underside of arm 262 at its other end, serves to keep the arm in its upward position at which point a work piece falling into the steadyrest would first be engaged by the recessed arcuate portions in arms 262 and 263 and then due to its weight be gently positioned within the steadyrest shoe III.

During the operation of the machine, the camshaft is slowly and constantly rotating and the action of the cams I14 and 235 and arm I20 are so timed in relation to each other than when the steadyrest is in position to receive a fresh work blank, the wheel is withdrawn from grinding position and the work engaging heads are completely retracted.- Figs. 3 and 5 of the drawings show the relative positions of the operating mechanism just as the grinding wheel has completed a grinding operation. Since camshaft H9 is always rotating in a counter-clockwise direc-' tion (Fig. 3) the roller I88 is engaged immediately upon completion of the grinding operation by the rise of feed cam I14 causing the lever arm I98 to move in a clockwise direction and lift chain I94 and weight 202. The upward movement of chain I94 rotates sprocket I in a clockwise direction and acts through the associated feeding mechanism to move the grinding wheel back away from the grinding zone. At the same time that the rise in cam I14 starts the wheel away from the work, roller ,I I5 strikes the depending lever I28 and causes the spindles 61 and 68 .to withdraw the driving heads from engagement with the work. Before the roller I88 has been engaged by the high point on the feed cam I14, roller 236 is engaged by the high point of cam 235 moving

valve pistons

238 and 239 to their upper position (shown in dotted lines of Figs. 3 and 11) thereby releasing spring 220 within cylinder 2I5 and causing the finished work piece W and steadyrest 2 I 0 to be withdrawn from the grinding zone.

As the steadyrest is withdrawh from the grinding zone, the finished work piece supported thereby is automatically ejected therefrom by the slop-' ing end faces of the work receiving arms 262 and.

263 as shown in Fig. 8. Upon being ejected from the steadyrest, the finished work piece is permitted to fall into a chute 215 (Fig. 6) from which it may slide into a bin, not shown. The chute 215 is fixedly supported by a bar 211 passing through the work supporting mechanism and firmly clamped to the yoke member 205. by nuts 219 and 280 screwed upon oneend of a threaded portion 28I on bar 211. It vwill be noted that when the steadyrest member is moved forward into the grinding zone, the chute 215 is received within the recess 283 within the block 60 which is moved by piston 2I6 and its associated parts.

Thus, the chute 215 always remains in a fixed position.

.piece being ground and arranged to serve as the After the finished work piece has been ejected, the rearward movement of the steadyrest continues until the piston 2l6 engages stop screw 232 and the empty steadyrest lies directly below the magazine mouth as shown in Fig. 7. At this time a work blank falls from the magazine into the steadyrest and is broken in its fall by first being caught by the recessed portions within the arms 262 and 263, one of said recessed portions being indicated by the dotted line 265 in Figs.

' 5, '1 and 8. The operation of the machine is so timed that the roller 236 now passes to the low point of dam 235 causing

pistons

238 and 239 within the valve 221 to close the exhaust port 251 (Fig. 11) and again enter fiuid under pressure into cylinder 2I5 moving piston 2I6 forward against the tension of spring 220 and thereby moving the fresh work blank into grindingposition. Dueto the fact that the workreceiving arms 262 and 263 are spring supported, the forward movement of the work blank within the steadyrest will permit the arms to spring out of the way. The anvil,2I-'0 also moves forward at this time since it is supported by the block 60, and presents its top face 2I I under the next work blank within the magazine thereby permitting only one work piece to feed into the steadyrest per grinding cycle.

The'escape valve I 42 controlling the exhaust of air from the dash pot cylinder I40 has been so regulated that the weight II2 may lower as soon as a new work blank is presented in grinding position thereby causing the spindles 61 and 68 to move axially toward the work, grip it and rotate it until completion of the grinding operation. As soon as the work has been automatically presented in grinding position, the high point of cam I14 passes roller I38 thereby causing the wheel to rapidly approach the work supported by the steadyrest and go through another automatic grinding cycle. It will be seen that the operation of thismachine is entirely automatic and it is only necessary to maintain duplicate work blanks within the magazine.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A grinding machine for round work comprising a rotatable grinding wheel, a work support having a work supporting surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to constitute the sole support and hold the work in correct grinding relation with the wheel, means to cause relative feeding movement between the wheel and the work support to grind the work and non-supporting means independent of the work support to cause the work to rotate at a controlled rate in the same direction-as the wheel at the point of contact.

2. A grinding machine for round work comprising a rotatable grinding wheel, a work support having a surface engageablewith and shaped to support the peripheral surface of the work sole support to hold the work in grinding relation with the wheel, means to cause a relative feeding movement between the wheel and the work support to grind the work and a work driving mechanism including a universal driving connection engaging the ends of the work which port towards and from each other through a preentire length of the portion being ground and serve as thesole support therefor, means independent of the work support to grip the work piece and rotate it in thesame direction as the wheel rotation at the point of contact while supported and positioned in the'grinding zone solely by the work holder, and means to-cause a relative feeding movement between the grinding wheel and the work holder to grind the work.

5. A grinding machine comprising a rotatable grinding wheel, means to rotate the wheel, a work holder arranged to peripherally support a cylindrical work piece substantially throughout its entire length, means independent of the work holder including two driving members which engage the ends of the work piece, means to simultaneously and synchronously rotate said work engaging members to rotate the work while supported by the work holder and means to cause a relative approach between the grinding wheel and the work holder to grind the work.

6. A grinding machine for round work comprising a' rotatable grinding wheel, a work support peripherally engageable with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to cause a relative feeding movement between the wheel and the work supdetermined grinding cycle to grind a work piece to a given size and means independent of the work support to non-supportably rotate the work at a controlled rate while it is maintained in,

grinding position solely by said work support.

7. A grinding machine for round work comprising a rotatable grinding wheel, a work support peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, a cam con-=.

trolled mechanism arranged to feed the wheel and the work support relatively towards each other to grind a work piece to a predetermined size and means independent of the work support to cause the work to rotate at a controlled rate during the grinding operation.

8. A grinding machine for round work comprising a rotatable grinding wheel, a work support having a work supporting surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to cause relative feeding movement between the wheel and the work support in a predetermined cycle to grind work and from each other for a predetermined grinding cycle, means independent of the work steadying member to rotate the work while wholly supported by said steadying member, and mechanism arranged to discharge a finished work piece from the steadying member upon completion of the grinding cycle.

v 10. A grinding machine for cylindrical work comprising a rotatable grinding wheel, a work support peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to cause relative feeding movement between the wheel and the work supportin a predetermined cycle to grind work pieces successively, ineans in-' 11. A grinding machine comprising a rotatable grinding wheel, means including a work steadying member to support the peripheral surface of the work during a grinding cycle, separate means engageable with the work for rotating it while supported within thework holder, means for feeding the grinding wheel and work relatively toward each other during the grinding operation, mechanism arranged to discharge the finished work piece upon completion of the grinding cycle, and means for automatically and successively presenting work blanks to the steadying member in proper timed relation to the grinding cycle.

12. A grinding machine comprising a rotatable grinding wheel, means to rotatesaid wheel, a work supporting shoe arranged ,to peripherally support the work substantially throughout its entire length, means tomove the work holder towards and from the grinding wheel to present the work piece within the grinding zone, means to rotate the work within said shoe and means to feed the grinding wheel into the work duringthe work rotation to cause a grinding operation.

13. A grinding machine comprising a rotatable grinding wheel, means to rotate it, a work holder arranged to peripherally support a cylindrical between the work holder and grinding wheel to present the work in correct grinding relation to the wheel, two driving heads adapted to engage the ends of the work piece and rotate it at a controlled rate and means to simultaneously r0- tate said heads, thereby transmitting a rotary motion to the work piece during a grinding operation and means to feed the grinding wheel into the work during the work rotation to cause a grinding operation.

14. A grinding machine for round work comprising a rotatable grinding wheel, a work support having an extensive surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold thework in grinding relation with the wheel, means to cause a relative feeding movement between the wheel and the work support in a predetermined cycle to grind work pieces.

successively, means including a work gripping device engageable with the work to cause the work to rotate at a controlled rate in the same direction as the wheel rotation at point of contact, mechanism for automatically feeding work pieces successively into the grinding zone in timed relation with the operation of the work gripping mechanism and the operation of the grinding cycle and means for automatically discharging finished work pieces from the grinding zone upon completion of the grinding operation.

15. A grinding machine comprising a rotatable grinding wheel, means to rotate said wheel, a work holder arranged to support a cylindrical work piece upon its peripheral surfaces, means providing a relative movement between the work holder and the grinding wheel whereby the work may be maintained within the grinding zone,

means independent of the work holder to engage V both ends of the work piece and transmit rota tion thereto, means to eject the work piece from the grinding zone upon completion of a grinding grinding wheel, a single work support opposed,

to the grinding wheel which has an extensive hollow surface shaped and arranged to contact with the cylindrical surface of the work and serve as the sole work support during the grinding operation, a non-traversing support for holding the wheel immovable axially, means to rotate the wheel in a direction towards the work support at the line of'grinding contact andthereby.tending to hold the work within its support, means to cause a relative feeding movement between the wheel and the worksupport, and a positively rotated work driving device which engages the work at a point remote from the surface contacting with the work support and serves, without centering or supporting the work, to rotate the latter in the same direction as that of the wheel at the line of grinding contact and at a controlled rate.

17. A machine for grinding a work piece ha ing a cylindrical surface comprising a rotatable grinding wheel, a single work support opposed to the wheel which is engageable with and shaped to support said cylindrical surface and serve as the sole support to hold the work in correct grinding relation with the wheel, means to feed the wheel and the work relatively towards each other and cause the work to be ground, and opposed driving means which frictionally grip the opposite ends of the work and serve to rotate the work during the grinding operation without supporting or centering the same. 18. A grinding machine for grinding a round work surface comprising a rotatable grinding wheel, a support engageable with said work sur-- face and shaped to serve as the sole work support during the grinding operation, means to cause a relative in-feeding movement between the wheel and the work'support to grind the work, a pair of work rotating members which are reatively movable into engagement with the opposite ends of the work, and means tending to hold said members in frictional and yielding engagement with the work ends, whereby the latter is rotated within its support by the end-pressure oil said members;

19. A machine for grinding around work surping device j e ageable with mechanism, including work gripping members frictionally engaging the-opposite ends of the work, a positively rotated driving shaft and a flexible connection between said shaft and a gripping member, which serves to rotate the work within its support without supportingor centering the same.

20. A grinding machine comprising a rotatable grinding wheel, a work support having an extensive surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the. wheel, means to cause a relative feeding movement between the wheel and work support in a predetermined cycle to grind work pieces successively, means including a work gripping device engageable with the work to cause it to rotate at a controlled rate, and'meansto automatically move the work support into an operative position for grinding and to an inoperative position after grinding to facilitate insertion of work pieces.

21. A grinding machine comprising a rotatable grinding wheel, a work support having an extensive surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to cause a relative feeding movement between the wheel and work support in a predetermined cycle to grind work pieces successively, means including a work gripping device engageable with the work to cause it to rotate at a controlled rate, and means including a fluid pressure piston and cylinder to automatically move the work support into an operative. position for a grinding operation and into an inoperative position after grinding to facilitate insertion of work pieces.

22; A grinding machine for cylindrical work- -comprising a rotatable grinding wheel, a work support having an extensive surface peripherally engageable and shapedto mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to cause a relative feeding movement between the wheel and work support in a predetermined cycle to grind work pieces successively, means including a work gripping de-' vice engageable with the work to cause the work cessively to said work support when it is with-,

drawn to an inoperative position.

23. A grinding machine comprising a rotatable grinding wheel, a work support having an exten-.

sive surfaceperipherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to hold the work in grinding relation with the wheel, means to feed the grinding wheel toward-and from the work support in a predetermined cycle to grind work pieces successively, means including awork gript e work to cause the work to rotate at a controlled rate, means including a fiuid pressure piston and cylinder to move said work support into or out of an operative position, means including a control valve actuated by and in timed relation with the cyclic movement of the wheel to control the admission of fiuid to said cylinder to move the work support to and from an operating position, means to eject a finish ground work piece from said work support when the work support is moved to an inoperative position, and a work piece hopper arranged to successively feed work pieces onto said work support when it is withdrawn to an inoperative position.

24. A grinding machine for cylindrical work comprising a rotatable grinding wheel, arwork support having an extensive surface peripherally engageable and shaped to mate with the ground surface of the finished work piece which is arranged to support the work in grinding relation with the wheel, means including a work gripping device engageable with the work to cause it to rotate at a controlled rate, means to cause a feeding movement of the grinding wheel in a predetermined cycle to grind work pieces successively, means including a fluid pressure piston and cylinder to move said work support into an,

operative position, means actuated in timed relation with the cyclic wheel feeding movement to admit fluid under pressure to said cylinder to cause the work support to be moved into an operative position, means including opposed work driving spindles engageable with the end of the work in timed relation with the cyclic control mechanism to grip and rotate the work piece, means to return said piston and move said work support to an inoperative position after a grinding operation has been completed, means to eject the finished work piece during said withdrawal, and a hopper arranged to successively feed work pieces onto said work support when it is withdrawn to an inoperative position.

CHARLES H. NORTON.

ALBERT G. BELDEN.