US2137644A - Grinding machine - Google Patents

Description

Nov. 22, 1938. R A COLE 2,137,644

GRINDING MACHINE Filed March 26, 1936 4 Sheets-Sheet 1 I HH mm FRY/warm ADELE Nov. 22, 1938. R. A. COLE 2,137,644

GRINDING MACHINE Filed March 26, 1936 4 Sheets-Sheet 3 FFHYMUNJJ A.EUL E UAW - NOV. 22, 1938. R A COLE 2,137,644-

GRINDING MACH INE Filed March 26, 1956 4 Sheets-Sheet 4 gnaw WM EH YMDND A. Em. E

Patented Nov. 22, 1938 PATENT OFFICE GRINDING MACHINE Raymond A. Cole, Worcester, Mass., assigno'r to Norton Company, Worcester, Mass., a corporation of Massachusetts Application March. 26, 1936, Serial No. 7035i? 11 Claims.

. The invention relates to grinding machines, and

with regard to its more specific features to a size controlling apparatus therefor.

One object of the invention is to provide an efficient work sizing apparatus. Another object of the invention is to provide a compensating mechanism of simple and practical construction. Another object of the invention is to make a grinding machine of a certain type substantially automatic in operation. Another object of the invention is to improve the machine disclosed in United States Letters Patent No. 1,779,779 to Charles H. Norton. Another object of the invention is to provide a size controlling mechanism for a machine of the type disclosed in the aforesaid patent to Norton. Another object of the invention is to provide an eihcient transmission mechanism for a grinding machine having a turret wheel, a cross slide operating mechanism and a work sizing and compensating apparatus. Another object of the invention is to provide a simple size controlling apparatus for an external grinder.

Another object of the invention is to provide a control preventing the size controlling apparatus from over-compensating. Another object of the invention is to provide an efficient and practical compensating apparatus to compensate for reduction in diameter of a grinding wheel while the machine is operating. Another object of the invention is to provide a size controlling apparatus and improved turret drive which may be incorporated by way of addition to a machine as disclosed in the aforesaid Norton patent. 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 many possible embodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of a grinding machine incorporating the apparatus of this invention;

Fig. 2 is a transverse view of the cross slide and operating mechanism therefor, portions of the machine frame being broken away more clearly to show the mechanism, and the compensating mechanism being shown in cross section ,on the line 22 of Fig. 1, Fig. 2 showing the parts in a different position from Fig. 1;

Fig. 3 is a vertical sectional view taken on the line 3--3 of Fig. 1, illustrating the transmission mechanism;

Fig. 4 is an enlarged view, partly in front ele vation and partly in vertical section, of the size controlling mechanism; 5

Fig. 5 is a view, partly in side elevation and partly in section, of the apparatus shown in the left-hand portion of Fig. 2 but on an enlarged.

' scale;

Fig. 6 is a sectional view taken on the line 6+G id of Fig. 5 and illustrating the compensating pawl and ratchet and electromagnetic drive for the pawl;

Fig. 7 is a sectional view on an enlarged scale and on the line 1-7 of Fig. 1, showing further iii details of the transmission and including the Geneva drive;

Fig. 8 is an enlarged fragmentary vertical sectional view on the line 8-3 of Fig. 1, showing the magazine, turret, size control mechanism, and 20 swastika work piece removing apparat Fig. 9 is a fragmentary view similar to Fig.8, showing the parts in a diiferent position;

Fig. 10 is a wiring diagram.

For a clearer understanding of the present 25 invention, reference should be had ,to Charles H..- Norton Patent No.'1,779,779 dated October 28, 1930, above referred to. Considering now Figure 1, the. machine may comprise a suitable base or frame 20 supporting work heads 25 and 22in. 30 which are rotatably mounted coaxial spindles, not herein disclosed but shown in the Norton patent, having on the ends thereof work gripping disks, also disclosed in the Norton patent, which are movable axially to engage the work piece being 35 ground. As indicated in Figs. 1 and 2, there is provided a grinding wheel head 23 having hearings for rotatabiy mounting a spindle 2d upon which is mounted a grinding wheel 25. The wheel head 23 is supported upon the usual cross it) slide 25 for movement toward and away from the work pieces being ground.

Considering now the cross feed and adjustment of the position of the grinding wheel 25, and refer-ring to Figure 2, the machine has a feed screw 45 3d engaging a half nut 35 which is attached to the cross slide 26. To the front of the feed screw 3G is fastened a gear 32 which meshes with pinion teeth 33 on the rear of a shaft 35, both the feed screw 30 and the shaft 33 being journaled in suit- 59) able journals in the machine frame. A gear 38 is fastened to the shaft 35 and meshes with a gear 37 fastened to a shaft 38, also journaled in the machine frame. Rotation or oscillation of the shaft 38 moves the cross slide 26 and therefore the grinding wheel 25, and the angular position of the shaft 38 therefore determines the position of the grinding wheel 25 with relation to a work piece.

Turning'nowto Figure 3, the machine is provided with a'main drive shaft 40 which may be driven from any suitable source of power. Grindshaft 48 and meshes with a gear 52 on a'shaft 53 mounted in journals 54 and 55. The gear 52 meshes with a gear 56 which is mounted on a shaft 5'! supported by journals 58, 59 and 68. On the front of the machine is a cam wheel 8| fastened to the shaft 51. 4

The mechanism, so far described is or may be virtually the same as that shown in the aforesaid Norton patent. The cam. wheel 5| operates to oscillate'the shaft 38 in a manner that will-be presently described and operating, except for the .-compensation feature, like the mechanism described in the Norton patent. I provide, however, a different drive for the turret wheel oper- 4 ating through a Geneva motion which is positive and accurate, the transmission for which I will now describe.

Fastened to the'shaft 51 is a bevel gear 65 which meshes with a bevel gear 65 fastened to a vertical shaft 61 which is journaled in bearings 68 and 59. On the upper end of the shaft 61 is a bevelgear ill meshing with a bevel gear H which is fastened to a shaft 12. Referring now to Figure 1, the shaft 12 is journaled at the righthand end of the machine frame in a journal 14 and otherwise as will appear. The shaft 12 is horizontal and on the extreme left-hand end thereof is a Geneva locking partial cylinder 15.

As better shown in Figure '7, also mounted on the shaft 12 is a Geneva arm 16 on the end of which is a Geneva pin'l'l which fits in radial are eight slots 18 and eight cut-out segments 80,

' slots 18 of a Geneva plate 19, which is the driven element of the Geneva motion. The plate 19 has segment cut-outs exactly fitting the partial cylinder 15 for locking the parts together .between angular motions. This driving mechanism thus constitutes a Geneva driving mechanism intermittently to rotate a shaft 8| to which the plate 9 is fastened. Insomuch as there eight revolutions of the shaft 12 procure one revo lution of shaft 8| by intermittent stages. A Geneva drive of this type holds thedriven part rigidly in a definite position betweeneach angular motion. Furthermore, angular motion starts gradully, accelerates to a maximum velocity, and

slows down gradually to a stop. While some clearance for proper operation of such a mechanism may exist between the partial cylinder 15 and the cut-outs 88, as grinding thrust is always in a single direction and the-clearance may be the same for every one of the cut-outs 80, each successive work piece will be held, during grinding, at exactly the same position which maybe determined within plus or'minus a half a thousandth of an inch. However, plus or minus a half a thousandth of an inch variation in the .vertical position of the work piece will,- owing to the largefdiameter of the grinding wheel, make a'variation in size of the work piece of less than one-half of a ten thousandth and this is still an incommensurable figure in grinding of cylindrical work pieces. Therefore, this drive for the turret of the Norton patent greatly improvesits action. Furthermore, through the transmission described, I am enabled to drive the work piece remover which passes work pieces under the size controlling device with a motion which is synchronized with relation to the turret. This mechanism and its drive will be fully described hereinafter.

Considering now the control of work pieces in this automatic machine, and referring to Fig.

8,.there is provided; as in the Norton patent re- 'ferred to, a work piece holding magazine 85. This may be simply a trough or an inclined slide upon. which a. number of workpieces may be placed. I provide a stop 86 to prevent the work pieces from overrunni rig the turret 8I.' The turret81 may be formed substantially as shown in the Norton patent, and may consist of two identical plates fastened to the intermittently operated shaft 8|, and in this present embodiment of the present invention I show it as having eight work piece receiving notches 90, to correspond with the eight divisions of the Geneva driven as an escapement feedingand work holding device.

Referring now to Figs. 1 and 7, fastened to the shaft 12 isa gear which is located close to an additional journal 94 for the shaft 12. The gear'95 meshes with a gear 95 mounted on a stud 91 projecting from a bracket 98 in which i formed the journal 94. The bracket 98 also provides. an additional journal 99 for' a shaft plate 19.. After a number of work pieces are I08 to which is fastened a gear llll meshing with p the gear 95. As the shaft 12 is continuously rotated, the shaft "ID will also be continuously rotated and in the same angular direction, that is to say, counterclockwise, Figure '1.

Referring now to Figures 1 and 8, I provide a casting. I05 having a right angle web or base portion M5 for attachment to the machine frame The parallel no prises four arms ll8 projecting from a central hub H1 and each arm having an arcuate tip 8, each extending in the same direction. In Figure 8 one of the arms H5 is shown engaging work piece #I which is on the track comprising the parallel portions or rails 0, I] l, the work piece I being on track portion I20 which is straight-and horizontal. Work piece #2 rests upon track portion I22 which is separated from the track portion I by an intervening track portion I2I with a steep grade. Work piece #2 is preventedfrom dropping down the steep grade lfilby means of the arcuate portion II8 of one of the arms II6. Track portion I22 merges into arcuate track portion I23 which follows the contour of the turret 81.

The work piece #3 is, as shown in Figure 8, restrained from rolling down the track portion I22 by arms of one of the work receiving pockets the grinding wheel forward and back to procure.

a cutting operation on each successive work piece.

Referring now to Figures 1, 2, 5 and 6, the cam wheel BI rotates counterclockwise and is engaged by a roller I26 on the lower end of a lever I21 having an arcuate upper portion I28, the lever I21 being pivoted on a stud I29 projecting from the front of the machine. When the cam portion I strikes the roller I26, the lever I21 is rocked clockwise. A clamping member I30 adjustably mounted on the arcuate portion I28 has connected to it a chain I3I passing over a sprocket I32, the lower end of the chain being connected to a Weight I33 mounted in a casing I34 attached to the machine base 20. The weight I33 keeps the chain I3I taut, and therefore the position of the chain is determined by the position of the cam 6|. The portion i25represents a quick retreat of the grinding wheel, while the remainder of the periphery of the cam Bl represents a slow advance of the grinding wheel. Owing to the arcuate shape of the portion I28, the position of advance is constant, so far as the intermittently actuating mechanism is concerned,

but the position of retraction is variable.

The sprocket I32 is formed on a hub I35 which is integral with a sector plate 36. A casing I31 is secured to the plate I36. As shown in Figs. 5 and 6, the casing I31 has a bottom portion I39 and the parts within it are substantially insulated from dust and the like. In the plate I36 is a journal I40 for a ratchet wheel hub i4! to which is integrally attached a ratchet wheel 2. In the hub MI is an internal gear form into which fits one end of a long pinion gear I43. By means of a shaft I44, a collar I is attached to the gear I43; the shaft I44 has on the front thereof a knurled knob I46 integral with a dial I41.

Collar E45 is journaled in a. journal I50 formed on the end of an arm I5I which is loosely mounted on the front end of the shaft 38. The journal I58 has a rearwardly projecting portion I52 detachably secured by means of a screw pin I53 to a projecting portion I54 integral with the plate I36, Therefore, arm I5I and plate I35 move as a unit. A spring pressed friction I55 engages the collar I45 and constitutes a friction device to hold the parts including the pinion gear I43 in adjusted position. The pinion gear I43 meshes with a large gear I58 which is fast upon the shaft 38. Thus, if the pinion gear I43 is not permitted to revolve, angular motion of the sprocket I32 and therefore the plate I35 results in equal angular motion of the shaft 38, the drive being through the gear I43 which acts as a lock. But the gear" I43 can be revolved by hand and also automatically, as will be described.

Referring now to Figures 5 and 6, I provide a slide I58 which is movable in ways HI and W2 provided in the plate I36 and the casing I31 re-. spectively. Referring now to Figure 6, a. pin I63 extends through the enlarged end I64 of the portion I39 of the casing I31 and extends into the slide I60. The pin I53 has a tight fit with one of the two parts and a loose fit with the other one; for example, it is shown as slidably keyed to the slide I60. At the other end of the connecting portion I38 is a support I65 for a solenoid I56 having a solenoid core I61 extending into the slide I and attached thereto by means of a screw I58. A boss I18 projects upwardly from the slide I60 and has a bore I1I perpendicular to the motion of the slide. In the bore I1I is a pawl I12 which is spring pressed-by means of a spring I13 towards the ratchet wheel I42. Spring I13 is backed up by a removable cap screw energized, the slide I50 and pawl I12 are moved to the right, Figure 6, and move the ratchet wheel I42 a. distance of one or more teeth. The distance which the pawl moves may be adjusted by means of a brass screw I15 passing through a brass boss I16 in a brass plate II11 secured to a projection I18 of the portion I39 of the casing I31. The screw I15 has a knurled head Hi0 and a locking nut I8I. The parts mentioned as of brass are merely preferably of any non-magnetic material in order not to interfere with the action of the solenoid I65.

Thus automatically at any time the gear I52 may be" turned, by one or more ratchet teeth thereof, whichacts to rotate the gear I58 through a smaller angular distance. It matters not whether the whole unit is moving or not, since angular motion of the gear I43 which is driven by the ratchet I42 efiects a displacement between the driving member I36 and the driven gear member I58 and so alters the relation between them and advances the limit position of the grinding wheel for each cycle of machine operation. At any time the same thing can be effected manually by rotating the knob I45 in a clockwise direction. However, the operator may wish to make an adjustment inthe other direction, in which case he will grasp the knurled head I46 and pull. A spring I83 pressing against the collar I45 holds the gear I43 in engagement with the internal gear form in the hub t ll, but by pulling on the knurled head I46 the gear M3 may be pulled out of this gear form. This disconnects gear l43 from the ratchet I82, and under such conditions adjustment may be made in either, direction. If the adjustment is a major adjustment, as for the grinding of a different size of work piece (perhaps involving substitution of a different turret 81), the arm I5! and gear I58 may be revolved any number of times without moving the plate I35 and sprocket I32, simply by unscrewing the screw pin I53 and thus breaking the connection between plate I36 and arm I5I, at the same time withdrawing the gear I43 from the internal gear form in the hub I4I. For the purpose of revolving the arm I5I, I provide a. handle I84 in addition to the knurled head I45. This handle I84 projects from a counterweight I85 which is provided to balance the parts including the .casing I31, ratchet I42 and the other parts associated therewith and just described.

By reason of the fact that the cam wheel 6| I14; When the electromagnet I66 is till is operated from a driving mechanism which also drives the Geneva pin IL-the turret 81 is synchronized with the motion of the cam wheel 6|.

Furthermore, every revolution of the cam wheel ,6I is accompanied by arevolution of the pin 11, as the gearing between these elements is a .one to one gearingl Insomuch as there are eight slots 18 .in' the Genevaplate I9, asingle revolution of the turret 81 represents eight revolutions .of the cam 6| and, therefore, eight complete reciproeations of the grinding wheel 25. The timing of the turret and the cross slide movement is such that each workpiece is stationary and in. grinding position, as shown in Figure 8, until the wheel 25 has advanced to its limit position and remained there for a short length of time to spark out, and has just started backward'on its rapid retraction, whereupon the turret 8I- revolves one step to carry the next work piece, for example-the work piecea 6, into grinding position.' The work piece 6'will have reached grinding positionab'out the time the grindingwheel has been fully retracted, or-

at least' before the grinding wheel has been subs'tantially advanced toward the-work piece. The rise I25 on the cam 6| represents a retraction suiflcient to measure theJargest diilerence between unground and ground work pieces and it will be seen that the remainder of the cam 6| represents a slow movement. Thus, the entire grinding operation is performed with the work piece in grinding position. The work rotating plates are synchronized with the mechanism ;herein described, as fully set forth in the aioresaid. patent to Norton, so that the work piece is' revolved positively as soon as the grinding wheel engages it. Furthermore, work piecerevolving plates are out of engagement with the work piece as soon as the turret 81 st'artst'o revolve.

Considering now the automatic sizing mechanism, and referring ,to Figures-1, 4, 8and 9, :I

.provide an upward extension l90 of the part III whichsupports a triangularly' shaped bracket I 9 I caliperinghead I96. -On the rod I95, which is screw threaded, is a 'pair of nuts I9'I which limit 'I9I is a bracket I92.

, with the rod I96.

integrally secured to it. On top' of the bracket An arm I93 is pivoted at V I'94- to :the bracket I92 and engages-the top of arod I95 to the-bottom of which is secured a the downward movement ofthe calipering head I96, A spring I on the rod I and inside of thetriangular bracket I9I' resiliently'holds the parts in their lowermost. position. A spring I99 v acts 'upon the lever I93 to keep it in engagement As best shown in- 'Figuresi4 and 10,-at the right-hand end of the triangular bracket I9I is an insulating sleeve; 200 and at .the right-hand "end of the lever I'93 is, an insulating sleeve 20I.

"-rninal screw 203 'extends through the sleeve An adjustable terminal screw. 202 extends through thesleeve 200.and an adjustable ter- 20I.. Referring now to the wiring diagram of, Figure 10; a battery 206 has. one terminal ounded, as showr'rat 206. A conductor 20! connects the other .end "of the battery 205 to the terminal screw 2I13 The'trminal screw 202 is connected by a conductor 208 ,to'one terminal 209 of the solenoid I66. The other terminal 2| 0 of the solenoid I66 is connected by means of a conductor- 2 to a terminal .2 I2 of a solenoid 213-. The other terminal 2 of solenoid 2H is connected by means ofa conduc- .tor 215 to a terminal 2l6 secured directly to the solenoid core 2II. A contact detent 2'I8 which .minus,

-sandth undersize.

is secured in the solenoid 2I'I is normally in engagement with the contact detent 2I9.- The contact detent M9 is grounded as'show'n at 220, this being a diagrammatic way of representingthat it' is uninsulated from themachine as a whole. The ground 206 represents the machine as a whole and, therefore, when the screws 203 are brought together, both solenoids I66 and 2I3 are energized. Energization of the solenoid I66 advances the limit position oi the grinding, wheel through mechanism already fully described.

, The adjustment of the terminals 202 and 203 and of the nuts I9! is such that, so long as the work piece'is not oversize, within' certain limits, the screws .202 and 203 will not come together.

Therefore, no: change will be made in the-setting of the machine. But when, as and if a particular work piece is oversized, the terminals 202 and a nism is set to act whenever a work piece is one tenth of a thousandth oversize, and the compen- 'sating adjustment istwo tenths of a thousandth of an'inch. This keeps the machine, theoreti- -cally, producing work pieces one tenth of a thousandth either way of the required size, which as a practical matter; would result in holding, work pieces to withinthre'e ten thousandths plusor The calipering head I96 also operates as a stop to hold the work piece in position before it is positively moved by the four armedswastika wheel 6.. Referring now to Figurc 9, the work piece 2 is held inpositionbythe calipering head I96 which in tum'holds the work piece 3 above the sharp incline I2I and'until such time-as the next arm 'of the swastika wheel engages the work piece 2. The arcuate portion I I8 of the swastika wheel-arm H6 receives theshock of work pieces which are dropping'into theposition of the work piece 2 in Figure 9. The arcuate portion II 8 also holds back the work piece 2 (Figure 8) until the work piece I has been pushed under the calipering head I96 so that work piece 2 will not advance under the head I96 while it'is being supported by passage of the work piece I thereunder.

The p rpose of the solenoid 2I3 and associated mechanism' is to prevent over-compensation. For example, assuming thatwork piece I is one ltenth of'a thousandth of an inch larger than the exact-theoretical size, and all adjustments are properly made, work pieces 2, 3 and 4 will be oversized. As the work piece-#I passes under the head I96 (assuming now the terminal'2l0 is grounded and the mechanism-now to be de scribed is not provided), the machine is compensated. "This will bring the theoretical size back to zero (assuming compensation is only one ten thousandth). But work piece #2 was already ground, and this will pass under the sizing mechanism in due course. This will also register as oversized, and actuate the compensating mechanism which will now compensate to..one tenth of a thousandth undersize. Work piece #3, likewise, ,will' cause compensation to two tenths of a thousandth undersize. Work piece. #4' will cause compensation to three tenths of a thou- Thus, undersized work pieces will be produced. .As there is a certain variation that cannot be entirely eliminated, a. theoretical undersized condition of three ten thousandths will in practice sometimes result in work pieces more than four tenths of a thousandth undersize.

Furthermore, it is desirable to compensate by two tenths of a thousandth which, under the conditions named, would produce undersized work pieces on an average seven ten thousandths undersized. Therefore, it is quite desirable to provide the mechanism to prevent such overcompensation. It is noted that the machine may be adjusted to cause compensation to occur in time to aifect #5 work piece, that is .to say to bring #5 work piece to the correct size.

To avoid this condition, I have provided mechanism whereby coincident with a compensation of the machine, no further compensation thereof will occur until all or nearly all of the series of oversized work pieces have been discharged by the machine. In other words, the compensating mechanism will not act again until a work piece reaches the sizing mechanism which was ground after the compensating was effective. This I term a hold-over mechanism.

Referring now to Figures 4 and 8, pinned to the shaft lflll is a collar 22!. On the shaft Hill and in engagement with the collar 22! is 'a fiber washer 222. A metal collar 223 is mounted loosely on the shaft I08 and projecting downwardly therefrom is the contact detent MB. A metal collar 224 is urged against the collar 223 by means of a spring 225 backed up by nuts 226 on the shaft lllli.

Friction will tend to drive the collar 223 and with it the contact detent 2 l 9 as the shaft Hi8 revolves, but there is no positive drive for the col lar 223 and it will remain stationary so long as the contact detent 2E8 is in engagement with it, as shown in Figure 8. But energization of the solenoid 2E3 draws downwardly the core 2i? and with it the contact detent 2H! and as the shaft M32 is constantly revolved, the contact detent 2 i 9. immediately starts to revolve and passes beyond contact with the detent 218. It comes in engagement with it again after four work pieces have gone underneath the calipering head H81 Removal of the detent 2l8 from the detent 2!? opens the circuit through the solenoids I66 and H3 whether or not the contacts 282 and 203 are together, and thus prevents over-compensation. The solenoid core 2 ll fits in the solenoid H3 and is prevented from turning therein by means of a key 228 fitting in a spline 229 in the solenoid. A spring 230 urges the core 2l'l upwardly and a stop screw 23% is provided to limit the upward motion and also for adjustment. This stop screw 23] extends through an L shaped supporting bracket 232 which supports the solenoid 213. The bracket 232 is made of resinoid or any other insulating substance and is attached to the machine base 20.

The swastika having the arms I I5 revolves constantly and at one quarter of the rate of revolution' of the cam wheel Bl. It revolves twice while the turret 81 is revolving once.

' incline 235, shown in Figures 8 and 9, into a basket or any other receptacle. Thus, the machine is completely automatic provided the magazine 85 is kept full of work pieces, and of course There are four arms 6 of the swastika wheel, whereas the magazineBB may be made as long as desired and contain a great number of work pieces.

It will be noted that the energization of solenoids I66 and 2&3 procures, automatically, the

deenergization thereof. But the contact between i detents 2|8 and 2H9 is a sliding contact and the solenoid 166 will have completed its work before the circuit is broken at detents 2l8 and 219. Detents 2l8 ,and'ZlSl are latch shaped to prevent contact on the reverse side and by means of the adjustments provided, this mechanism may be made to operate effectively, as described.

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 or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:--

1. In a grinding machine, a grinding wheel, 2

means for presenting work pieces seriatim to the grinding wheel, means for measuring the size of each work piece after it is ground, compensating mechanism to change the position of the grinding wheel with respect to a work piece responsive to the means for measuring the size of each work piece, and means to stop operation of the compensating mechanism for a limited time to prevent over-compensation by reason of passage of a plurality of work pieces already ground through the means for measuring the size of each work piece.

2. In a grinding machine, a grinding wheel, means to advance and retract the grinding wheel relative to work pieces, means to feed work pieces seriatim to a grinding position relative to the grinding wheel and to discharge the work pieces after grinding, means to cause intermittent actuation of the means to advance and retract in timed relation with the. means to feed work pieces therein specified, of a hold-over mechanism to prevent over-compensation. I 4. A controlling apparatus for grinding machines comprising a track, a calipering head, and

a plurality of arms mounted on a hub to push work pieces along the track and under the head, the track being so positioned with relation to the head and so shaped that the head operates as a stop to provide escapement action of the apparatus.

5.- Controlling apparatus for grinding machines comprising a track, a calipering head, a swastika wheel, andmeans for revolving the swastikawheel, the track being so shaped that in conjunction with the head and the swastika wheel it acts as an escapement;

6. In a grinding machine, means to advance work pieces to grinding position and to discharge operated bythe head, a shaft upon' which the 6 them therefrom one by one, a track to receive the work pieces, a calipering'head, a plurality oi! arms mounted on a hub to move work pieces one to rotate, and an electric circuit; controlling thegrinding operation, said electric circuit including the contact whereby to stop operational the' control for a limited period.

7. In a grinding machine, a pair of parallel rails, a multi-armed wheel on an axis below the rails, the arms rising above the rails, a calipering head above the rails, contact closing mechanism wheel in a plane perpendicular to the plane of the the withrails and on an axis parallel to the plane of the I rails, a'sizing head above the rails, and means to revolve the wheel. by one under the head, electric mechanism oper- 10. In a grinding machine, a turret having work piece receiving pockets, a multi-armed wheel to move work-pieces subsequent to discharge by the turret, a calipering head positioned to measure work pieces moved by the multi-armed wheel, a transmission train-to move themultiarmed wheel, and a.Geneva motion operated by the transmission train to rotate the turret intermittently.

11. In a'grindingmachine; a grinding wheel, a turret having work piece holding pockets, the turret being positioned so that it brings work pieces adjacent the grinding wheel for grinding thereby, track means to receive the workpieces from the turret after they are ground, calipering mechanism comprising a plurality of arms extending radially Irom a central hub, the axis of which is perpendicular to the plane of the track,

a calipering head radially in-iine'with the arms,

means angularly to move the arms, thereby moving a work piece on the. track past the calipering head, and electric mechanism operated by the caliperihg head to work pieces.

compensate for over-sized RAYMOND A. COLE.

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