US2665526A - Automatic grinding machine - Google Patents

Description

Jan. 12, 1954 J. F. PELTON AUTOMATIC GRINDING MACHINE 5 Sheets-Sheet 1 Filed June 25, 1951 INVENTOR JOHN F. PELTON ATTORNEY Jan. 12, 1954 J. F. PELTON 2,665,526

AUTOMATIC GRINDING MACHINE Filed June 25, 1951 s Sheeiis-Sheet 4 w R Wm, Q M N Q m Q a Q I Q \q gm 3 N i I i N Q i :if a l l in 3 5 g m N INVENTOR JOHN F.PELTON BY ATTORNEY Patented Jan. 12, 1954 2,665,526 AUTOMATIC GRINDING MACHINE John F. Pelton, Kenmore, N. Y., assignor to Union Carbide and Carbon Cor of New York poration, a corporation Application June 25, 1951, Serial No. 233,375

21 Claims. (01. 51-103) This invention relates to an improved grinding machine for automatically feeding, grinding and ejecting a series of blanks. More particularly, the invention concerns a fully automatic machine for grinding points on tiny blanks of a hard material such as sapphire or ruby to form Styli such as phonograph needles.

Corundum crystals in the form of ruby and sapphire have been used as points in composite phonograph needles for some time. Until recently such needle points were relatively large, and easy to handle in a grinding operation. However, at the present time phonographs employ tiny corundum needle points as small as .05 inch long and .016 inch in diameter, having 45 degree symmetrical conical tips. Such tiny work-pieces have magnified the difiiculties of grinding this hard material, and have made it difixcult to obtain needle points which are uniform and symmetrical in shape, which are accurately dimensioned, and which are otherwise of high quality.

Fully automatic grinding machines constructed in accordance with the present invention have made it possible to produce tiny corundum phonograph needle points rapidly and economically, and with the important attributes outlined above. Such a machine, which is to be described in detail below, acts automatically to perform the following functions in grinding needle points:

A. A series of tiny cylindrical blanks is fed, one at a time, onto a longitudinal support at a feeding station near one end of the support.

B. The blank is advanced longitudinally along the support to a position just short of head-on contact with a rotating grinding wheel which is positioned at a grinding station adjacent the opposite end of the support.

C. The blank is thereafter advanced into initial contact with the grindingwheel and, as grinding of the blank proceeds, it is progressively advanced longitudinally an accurately measured amount toward the grinding wheel so that the latter grinds a complete conical point.

D. The blank is rotated rapidly on a fixed longitudinal axis whilein contact with the grinding wheel.

E. Upon completion of the grinding operation the grinding wheel is automatically retracted from the grinding station, rotation of the point is stop ed, and the point is ejected.

F. Then the next blank in the series is fed. upon the longitudinal support, the grinding wheel is returned automatically to the grinding station, and the above operations are repeated.

G. In the event that a blank becomes iammed 2 7 before being fed onto the support, the machine is automatically stopped.

H. The operations described above in paragraphs A to G are controlled synchronously in timed relation to one another by interlocking cams cooperating with the several functioning mechanisms.

One embodiment of the automatic grinding machine of the invention will be described in detail below to illustrate the principles involved. However, it is to be understood that changes in the construction and in the relative arrangement of parts can be made within the spirit of the invention. I

In the drawings:

Fig. 1 is a longitudinal sectional view of a needle grinding machine taken along the line l--i in Fig. 2;

Fig. 2 is a plan view of the machine looking from the top in Fig. 1;

Fig. 3 is a sectional view of part of the blank feeding mechanism taken along the line 33 in Fig. 2;

Fig. 4 is a schematic perspective view showing how a blank is ground in accordance with the invention;

Fig. 5 is an enlarged side elevational view of a needle point ground in accordance with the invention;

Fig. 6 is a sectional view taken along the line 6-6 in Fig. 1, parts being shown in elevation;

Fig. 7 is a sectional view taken along the line 11 in Fig. 1, parts being shown in elevation;

Fig. 8 is an enlarged sectional view taken along the line 8-8 in Fig. '7;

Fig. 9 is an enlarged sectional view of part of the blank-feeding mechanism taken along the line 9 9 in Fig. 2, parts being shown in elevation, the condition of the machine being such that a blank has been advanced to the grinding wheel;

Fig. 10 is an enlarged sectional view taken along the line I il-l 6 in Fig. 9, parts being shown in elevation and parts being broken away and shown in section, the condition of the machine being such that a blank has just been fed onto the longitudinal support but has not yet been advanced to the grinding wheel;

Fig. '11 is a sectional view taken along the line I l-I i in Fig. 9. with the blank-advancing device omitted for clarity;

Fig. 12 is a perspective view of a part of the blank-feeding mechanism shown in Figs. 9 and 10;

Fig. 13 (on the same sheet as Fig. 1) is a detailed side elevational view of 'a part of the cam mechanism of Fig. 1, showing the position of parts during actuation thereof;

Fig. 14 (on the same sheet as Fig. 1) is an end elevational view of a part of the machine as seen from the left in Fig. 1;

Fig. 15 (on the same sheet as Fig. 2) is a perspective view of a part of the blank-feeding mechanism;

Fig. 16 is a diagram showing development of the cam contours for synchronizing the functions of the grinding machine; and

Fig. 1'7 is a pictorial electricaldiagram of the machine.

GENERAL DESCRIPTION Generally in accordance with the invention, the automatic grinding machine comprises a platform P carrying a longitudinally extending horizontal work support S upon which a cylindrical blank is fed and is held during the grinding operation. A blank to be ground is fed laterally onto the support S by a-blank-feeding mechanismF located at a feeding station near one end of support S, and then is advanced along thesupport S by a longitudinally movable advancing device A which pushes the blank into pcsi-- tion adjacent a grinder G located at a grinding station at the opposite end of support S.

At the grinding station the blank is rotated on afixed longitudinal axis by suitable rotating mechanism R, such as a pair of rolls R1 and R2 located on opposite sides of the support S and rotating in the same direction on longitudinally extending axes. After its initial positioning adjacent the grinder G, the blank is fed progressively forward a short and accurately measured distance by a micrometer feed mechanism M cooperating with the advancing device A, so that the point can be completed.

Upon completing the grinding operation the grinder G is automatically'retracted. away from the-support S. the rolls R1 and R2 are stopped; and the needle point is ejected forwardly from the support by ejecting mechanism E, which constitutes a part of the advancing device A and which acts by a sharp longitudinal blow upon the latter to eiect the blank.

After ejection of the ground point the advancing device A returns rearwardly along the support S to the feeding station to receive from the-blank feeder F the next blank to be ground; During its return motion the advancing device A engages the blank-feeding mechanism F and; causes the latter to feed a blank laterally onto the support S after the advancing: device has cleared the feeding station;

All of the above described mechanismsare operated synchronously in timed relation" toone another by a suitable-cam control C which is located near the bottom of the platform P.

Fig. 5 shows a needle point 8 produced as-described above.

SPECIFIC DESCRIPTION Platform, P

by four pillors I3, and a hori ontal lower shelf l5'for the cam control mechanism C.

Work support 8 The longitudinal work support S comprises a horizontal bedplate 11 mounted. on; the top. of

4 the upper shelf II. A longitudinal channel 19 (see Fig. 10) for a blank is formed, on the top of bedplate I! by three side plates 2|, 22 and 23, the side plate 2| extending substantially the full length of the bedplate, the side plate 22 terminating at its rear end short of the rear end of the bedplate and adjacent the forward edge of theblank feeder F, and the sid plate 23 continuing from side plate 22 past blank feeder F and having a tongue 24 (see Fig. 11) which bridges the outlet from F.

A thin work rest blade 25 is removably and replaceable clamped by a spring finger 26 in av recession the side of bedplate I'I near its front end. The top surface of blade 25 is flush with the bottom of channel 19 and located between the rolls R1 and R2 to support a rotating blank during the grinding operation.

Grinder G The grinder G comprises a grinding wheel 29 stationed adjacent the front end of the work support S with its peripheral grinding surface 2! arranged head-on to the support. Grinding wheel 29 is mounted. on one end of a horizontal axle 3!. which. extends transversely of and normal to support S and is spaced both longitudinally of and transversely. above the top surface of workrest blade 25. and above the rotational axis of. the blank to be ground, so that the peripheral grinding surface 21 sweeps downwardly and forwardly between rolls R1 and R2 across the front end of. a blank to form a point thereon, as shown diagrammatically in Fig. 4.

The grindingv wheel axle 3i isjournaled in a bearing 33 carried on the rear side of a table 35 which ismounted on an upright bent post 31 and held in place by a set screw (not shown). Fine adjustment. of the grinding wheel assembly up, and down on the post is secured by a bolt, cap,- andv spring assembly 38. The other end of axle 3i protrudes from bearing 33 and carries a pulley 39 drivenby a belt 4t, which in turn is driven byan electric motor 43 mounted on the front. of table 35v on. the side of post 31 opposite bearing 33.

Post 31 extends down through an oversized aperture 45 in upper shelf II to a horizontal shaft l!- which is. pivoted at its ends on a pair of pivot pins 49, as shown in Fig. 7.

The weight of the driving. motor 43 and its position on the table 35 are such that the weight of the grinding wheel 28 is overbalanced and the post 3.! is normally urged in a forward and downward: direction to withdrawthe grinding wheel from its grinding station adjacent support S. At any given moment the position of the grinding wheel is-governed by a cam surface 50 of a flanged circularcontrol cam 5| rotating. with a cam shaft 53 which-is; journaled in a pair of spaced pillow blocks 55-on the lower shelf l5. Cam shaft 53 is drivenby an-electric motor'56 acting through a suitable sprocket, chain, worm and gear train 58. A lever arm 59 projects downwardly from the pivot shaft 41 and carries a cam follower 51 which is held against the cam surfac 50 by the weight of the grinder motor 43 and follows the-contour" of the. cam surface as the latter rotates, thus moving the grinderinto and out of grinding position.

Cam follower 51 is carried ona leaf spring which is secured at its upper end to the arm 59- and is-urgedstrongly toward the arm by the spring action. An adjusting screw 62 separatesarm: 59 and spring. 6.0.v by an. amount which is so adjusted that the grinder Gengages stop 6| slightly before cam follower 51 reaches the highest point on cam Further motion of the cam follower then flexes spring 60 and lifts the adjusting screw 62 from arm 59, forcing grinder G against the stop GI with a definite controllable force, thus avoiding the need for extremely precise adjustments in the system.

The surface'50 of grinder cam 5| is so shaped that during the major portion of its rotation the cam follower 51 is in contact with the high portion of the cam, as shown at a in Fig. 16, and the grinding wheel 29 is held at its grinding station adjacent the support S while the grinding of a blank proceeds. After a time interval determined by the rotational speed of cam 5|, when grinding has been completed, the cam follower 5'I enters the low portion b of the cam and the grinding wheel is retracted from its grinding station to permit the ground blank to be ejected. The cam follower remains in the low portion 1) until the next blank is positioned at the grinding station, whereupon the high portion a reengages the cam follower and restores the grinding wheel to its grinding station. The proper adjustment of the grinding wheel at the grinding station is accomplished by adjustable stops 6| carried by' a bracket 63 on the top of the machine. As a safety feature cam 5| has a radial pin 52 which can enter a slot 54 in arm 59 and act to pull the grinder from its grinding station if frictional forces or other obstruction should prevent the grinder from falling back by gravity. In normal operation the pin 52 never touches any part of arm 59.

For grinding the tiny corundum phonograph needle points for which this machine is particularly adapted, an extremely thin grinding wheel 29 is required. One type of wheel which has been found satisfactory is a metal-bonded diamond wheel three inches in diameter and 0.009 inch thick at its peripheral grinding edge 27.

Mechanism R for rotating blank during grinding A symmetrical point is ground on the end of a blank by rotating it rapidly on a fixed longitudinal axis during grinding. Rotation is accomplished by the pair of driving rolls R1 and R2 which are located on opposite sides of the support S at the grinding station adjacent the front end of the support. Both rolls are driven in the same direction by longitudinally extending axles 65 and 6'! which are journaled in and project rearwardly from hearing blocks II and 69, respectively (see Fig. 8 detail). Both axles 65 and 91 are in turn driven by a chain l'l running from an electric motor 19 to a pair of sprockets I3 and I5 on the rear ends of the axles. Sprocket i5 has a smaller pitch diameter than sprocket I3 so that the roll R1 rotates at a higher peripheral speed than roll R2, even though its diameter is less than R2, to hold the blank down on the work rest blade 25 during grinding.

The roll R1 has a peripheral surface 8| of rubber or a similar resilient gripping materal. The other roll R2 is formed of a hard metal such as steel. The axle 65 of the rubber-covered roll R1 is horizontal but the axle 61 of the steel roll R2 is tilted downwardly and rearwardly .at a small angle such as three degrees to maintain a blank in constant contact with the end of advancing device A while the blank is being ground. Both rolls dip into oil reservoirs such as that shown at 80 in Fig. 8. This oil is carriedup to the point of grinding to'serve as a coolant a'ndlubri cant. I

The rolls R1 and'Rz are arranged with opposed peripheral surfaces which pass close together and close to the sides of the work rest blade 25, the top of which is about level with the common diameter of the two rolls, as shown in Fig. 4, to support a blank 83 in the throat 85 between the two rolls just above the common diameter.

The roll driving motor 19 is controlled synchronously with grinder G by a switch 81 (see Figs. 1 and 17) which is actuated by a finger 99 on grinder pivot shaft 41. When the grinding wheel 29 is retracted from its grinding station,v thefmger 89 opens switch 81 to stop motor 19 and rolls R1 and R12. When the grinding wheel is restored to its grinding station in the manner previously described the finger 89 permits the switch 81 to close and starts the motor 19 and rolls R1 and R2.

Blank advancing mechanism A A blank 83 is placed upon the longitudinal work support S in alignment with the channel I9 when the advancing device A is in its fully retracted position (as shown in Fig. 10). The advancing mechanism A comprises a long push rod 9| which passes at its rear end through a bore in' an upstanding bracket 93, and has an intermediate portion passing through a bore in a block near the middle of platform P. Push rod 9| is held in its retracted position by a yoke 91 carried on the upper end of an upright lever 99 having a pivot ml at its lower end, the yoke being captured between two sets of abutment nuts I00 and I02 adjustably threaded on the push rod. A cam follower I03 between the ends of lever 99 is held by a spring I04 in constant contact with a circular flanged cam I05 which rotates with cam shaft 53. Cam follower I03 acts to retract the push rod 9| when on an ascending portion I01 of the cam, holds the push rod in fully retracted position momentarily (as shown in Fig. 10) when on a peak portion I09 of the cam, and permits the push rod to advance along the support S to carry the blank 03 from the feed station to the grinding station while on a descending camportion I II.

As the cam follower I03 traverses the descending portion III of cam I05 a coil spring H3, which is compressed between the bracket 93 and an annular hollow flange ||5 forming a partof the push rod, urges the push rod forward along support S. The bottom of flange H5 is keyed in a longitudinally slotted base plate IIB to prevent turning of the push rod 9| during its movement back and forth. The front end of push rod 9| engages the blank 83 shown in Fig. 10, and pushes it along the channel I9 into throat 85 between the two rolls R1 and R2, the movement of the blank being stopped when a shoulder M4 on the push rod abuts against a hollow bushing ||6 surrounding the push rod and threaded into block 95. The rotating grinding wheel 29 then is lifted into position at the grinding station by cam 5| and at the same time the switch 81 is actuated to start the rolls R1 and R2 so that the blank revolves rapidly on a fixed longitudinal axis just out of contact with the peripheral grinding surface of the grinding wheel.

Micrometer feed mechanism M Immediately after grinding wheel 7.9 reaches assumes thesrindine: station. the: blank is advanced into initial contact with the grinding wheel by the micrometerfeed mechanismM which moves the blank; slowly'forward into theygrinding wheel thereafter. Mechanism M- is actuated by a cam I11 (see Fig. 6), including an ascending portion I25-which moves a free end I23 of a lever II9 downwardly about a, fixed pivot I2I, a peak portion I21, and a descending portion I29 which permits the end I23 of lever II9 to rise under the influence of. coil springs I3I. Springs I3! arestretched between a stationary cross bar I33 near the top of the machineand a vertically movable lower crossbar I35, the latter being coupled to the-movableend. I23 of lever II9 by an adjustable coupling I31. Coupling I31 includes a socket member I36, plvotally secured to lever I I9, and a plug member I38 pivotally secured to cross bar I35 and slidablyadjustable in the socket member,- the position. of theplug being fixed by set screws.

Cross bar I35 also carries an upwardly extending vertical rack I39 which is 'slidable in a vertical guide I4I on the side of platform P. Rack I39 engage a pinion gear I43 on one end of a horizontal shaft I45 which is journaled in a bearing I41. Shaft I45 projects to a position above the support S and carries a helical gear I 49 which meshes with a helical gear II mounted on the hollow bushing I I6. Gear I49 is secured to shaft I45 by a set screw which can be loosened to permit the gear to be rotated freely to adjust the apparatus for different blank lengths and to compensate for wear.

After the initial contact of blank 83 with the grinding wheel 29 the descending portion I29 of cam II1 permits the rack I39 to rise, thus operating the helical gear I5I so that the hollow bushing IIB screws into the counterbore I55 and allows the push rod 9I to advance slowly toward the grinding wheel under the force of the spring II3, to complete the grinding of a. symmetrical point on the blank.

Blank ejection mechanism E Upon completion of the needle point the cam 5I permits the grinding-wheel 29 to be retracted from the grinding station, and at the same time the finger 89 actuates the switch 81 to stop the rolls R1 and R2. Immediately thereafter a wedge-shaped lug I51'on1the peripheral surface of the advancing mechanism cam I05 passes between a second cam follower I59 on the lever 99 and a cam follower I6I projecting from a second upright lever I63; which is also pivoted at its lower end I65 (see Fig. 14-)- The lug I51 separates the twolevers against the resistance of a spring I61 and withdraws the yoke 91 a short distance toward abutment nut I00. Lug I51 releases cam follower I59 while still engaging cam follower I6I, thus permitting lever 99 and yoke 91 to move forward rapidlyand" strike the abutment nut I02 a sharp blow to move push rod 9I a short distance longitudinally forward against the pressureof a coil spring I'II within the hollow flange II5, thus impelling the ground blank forwardly from the work support. Immediately thereafter the lug I51 releases cam follower I6! and permits lever I63 to return to its original position. This construction permits spring I61 to impart a strong'force-to lever 99 just before and during blank, ejection, when it is most needed, yet to be completely inoperative during the major portion of the camsrevolution.

Blankrfeed mechanism: F

Immediately after a ground point hasv been ejected from the support S the, ascending-portion I01 of advancing mechanism cam I05 forces the yoke 91 to engage abutment nut I00 and pullothe push rod 9| rearwardly away from the grinding station to the position shown in Fig. 10 to leave the feed station clear for introduction of the next blank from the feeder F, at the same time compressing the coil spring II3.

Meanwhile the ascending portion I25 of mi.- crometer feed cam II1 depresses the lever I I9-, causing rack I39 to rotate pinion I43 reversely, thereby, withdrawing bushing II5 fromcountenbore I55 andrestoring it to its original position where it can serve as a stop for the pushrod: 9i.

During the rearward stroke of push rod 9| 2. laterally projecting flexible spring finger I15 on top of the flange II5 engages a hook- I11 on. the free end of an actuator-arm connectingrod I19 which extends longitudinally rearward-1y from, a crankarm I8I, the latter being mounted on a vertical shaft I83 which is journaled in a feed block I85 located in a recess between the bearing block 69 and the bedplate I1. Connecting rod I19 is connected to crank arm I 8I by a con pler I86 slidably adjustable along the rod; and having a vertical pin I88 positioned within a slot I90 in the end of the crank arm.

During its rearward motion the connectingrod I19'compresses a spring I31 between 2. lug I89 and a cam block I9I. At the same time, the rod rotates the shaft I83 to turn an eccentric spud I03 on the lower end thereof which works ina groove I in a blank pusher or feed slide I 91, causing the latter to move transversely away from the bedplate I1 against the spring pressure of a safety switch 233 acting through a push rod 2.31 and a lever 235' (all to be described in detail here'- inafter) to permit the next blank I99 tube fed forwardly from a tube 293 onto a table 203. Table 203 projectstransversely into a slot inbedplate I1 and has a top surface level with the surface of the bedplate, thus in effect constituting a part of the bedplate.

When the push rocl 9I has been almost fully retracted, the finger I15 rides up an inclined cam surface 201 (see Fig. 15) which flexes the finger and raises it out of engagement with the hook I11. Thercupon the force of the compressed spring 81 restores the connecting rod iii] to its original forward position with hook i11' against a stop 208, thus actuating the crank arm I85 and shaft I03 to permit the spring pressure of safety switch 233 to move the feed slide i9! toward the bedplate I1 so that a tongue 259 on the slide pushes the next blank 599 along the table 203 into the path ofthe push rod 9!. At the same time the tongue 209 obstructs the outlet 2'I3 of tube 20I and prevents the passage of another blank onto the table 203. Slot N35 is made wide enough so that'eccentric pin I93 cannot push slide I91 forward if it should become jammed by a blank.

The push rod 9I then advances the blank I99 to the grinding station and the various operations are repeated; all as described previously herein.

Blanks are supplied one at a time to the table 203 through the long thin tube 20i having its outlet 2I3 adjacent the table 203 in position to dischargetheblanks thereon and against a step 295. The tubeZBI has an inlet 2I5 (see Fig 3) at its opposite and enclosed by a hollow block 2I 1 whose open end is provided with a cap- 219 to form a chamber 22l adjacent the inlet. A series of-blanks is introduced into the tube 20] in end to-end relation by removing the cap 2 I 9 and passing the blanks through the inlet 2l5. The cap 2 I9 is then replaced and the blanks are fed through the tube by supplying a fluid such as air or oil under pressure to the chamber 22! through a supply tube 223. Tube 20! is encased in a second tube 202 which protects the former by preventing kinking and other damage.

Electrical controls The several electric motors 43, 53 and 73 for driving the mechanisms described above are controlled by manual switches 225, 227 and 229 shown in Fig. 17. Grinder motor 43 and cam shaft motor 56 operate continuously when the ma chine is in normal use. Roll-driving motor '53 is started and stopped automatically by the switch 8'! (Figs. 1 and 1'7) in accordance with the position of the grinder G. . Motors 56 and 19 are provided with magnetic brakes to stop them quickly when the power is disconnected.

The machine is also provided with a pair of parallel-connected synchronized safety switches 23! and 233 in circuit with the cam-shaft-driving motor 56, which act to stop the camshaft if a blank becomes jammed in the feeding mechanism F and cannot be pushed onto the bedplate H by the slide I91. The operation is as follows:

(a) While a blank is at the grinding station the feed slide I9! is in its forward position as shown in Figs. 9 and 10 and a vertical switch lever 235, which is pivoted at its lower end at 236, acts through a horizontal push rod 23'! to allow. the spring-actuated safety switch 233 to be in its normally closed position so that the cam shaft motor 53 operates. At the same time the low part 240 of a cam 239 on the cam shaft 53 allows the second spring-actuated switch 231 to be in its normally open position.

(b) When the feed slide I91 moves to its rearward position preparatory to feeding the next blank onto the bedplate l'l, it operates switch lever 235 to open switch 233 against its spring pressure. Before switch 233 opens, however, the high part 24[ of cam 239 closes switch 23l so that motor 53 continues to operate.

When the feed slide I9! is again moved forward by the spring pressure of switch 233 to feed a blank onto the bedplate I! the switch 233 again closes and immediately thereafter the low part 2430f cam 239 permits switch 23! to reopen, sothat there is no interruption in the operation of motor 53 and cam shaft 53.

[(d) If the blank jams in the feed mechanism during step (0), however, the feed slide l9"! cannot move forward so that the lever 235 continues to hold open the switch 233. Meanwhile the earn 239 continues to rotate until its low part 243 allows the second switch 23! to open, whereupon themotor 53 ceases operation and the cam shaft 53 stops.

(e) Upon observing that the machine has stopped operating, the attendant corrects the jammed condition, the feed slide l9! resumes its forward movement, and cam shaft sumes operation.

' The grinding machine described in detail above has been used successfully for grinding ruby phonograph needle points having a length of .05 inch and a diameter of .0 6 inch at a rate greater than 200 per hour. Only occasional attention is necessary to perform such functions as filling the assigns i 1 i s; ai er blanks. r ces motor 53 rethe work rest blade 25 when it has becom worn, adjusting the various operating parts to com-f pensate for wear, and correcting the infrequent jamming of the blank feed mechanism.

What is claimed is:

1. A grinding machine comprising, in combi-' nation, a support for a blank to be ground; feed mechanism for successively feeding blanks one at a time onto said support at a feeding station; a grinder positioned head-on to said support at a grinding station adjacent one end thereof; advancing mechanism movable longitudinally of said support toward and away from said grinder for advancing a blank from said feeding station along said support to said grinder at said grinding station; rotary means at said grinding station for rotating such blank on a fixed axis during grinding thereof; mechanism for moving such blank toward said grinder during the grinding thereof; mechanism operable to retract said grinder from said grinding station when "grinding of said blank is finished, and to restore said grinder to said grinding station thereafter; mech anism for ejecting said blank from said grinding station during retraction of said grinder; and mechanism for returning said advancing mechanism to said feeding station to receive the next blank to be ground.

2. A grinding machine in accordance with claim 1, also comprising interlocked cam mem bers cooperating with said several mechanisms for synchronously actuating said mechanisms to feed, grind, and eject said blanks automatically and successively.

3. A grinding machine in accordance with claim 2 wherein said feed mechanism for feeding blanks comprises a table; means for feeding a line of blanks end-to-end in a direction longitudinally of said support, and onto said table one at a time; a pusher movable transversely toward. and away from said support, said pusher during movement toward said support pushing a blank from said table into the path of said advancing" mechanism and blocking the movement of the pusher away from said support whereby the next blank in line is fed onto said table; releasing. means for releasing said pusher from connection.

with said advancing mechanism after said next blank in line has been fed onto said table; and

means urging said released pusher toward said support for pushing said blank into the path of said advancing mechanism while the latter is in' retracted position.

4. A grinding machine in accordance with claim 3 wherein said means for feeding a line of blanks comprises a feed tube having an outlet adjacent said table in position to discharge blanks thereon, and means for applying pressure to said blanks in said tube for urging said blanks therethrough.

5. A grinding machine in accordance with claim 4 wherein said feed tube has an inlet remote from said outlet, wherein said machine also said inlet providing comprises an enclosure for a chamber adjacent thereto, wherein said means for applying pressure comprises a conduit con.

nected into said chamber for supplying fluid under pressure thereto, and whereinjsaid enclocreased sureis provided with accessmeans whereby a new supply' of blanks may be introduced into said tube through said inlet.

6. A grinding machine in accordance with claim 3 wherein said pusher comprises an actuator arm; wherein said connectin means is a finger on said advancing mechanism engageable with said arm, and wherein said releasing means isa cam surface cooperating with said finger and acting to release said finger from engagement with said actuator arm.

7. A grinding machine in accordance with claim 2 wherein said means for rotating such blank comprises a pair of driven rolls located on opposite sides of said support and rotatable on longitudinally extending axes, said rolls having opposed peripheral surfaces passing close togather and to said support, said peripheral surfaces forming a throat therebetween to receive sufih blank.

8, A grinding machine in accordance with claim 7 wherein said grinder has the peripheral surface thereof passing .through said throat in position to grind a point on such blank while such blank is rotated by said rolls.

3. A grinding machine in accordance with claim 3, also comprising an electric motor operating said interlocked cam members, first and second parallel switches in circuit with said motor, control means operable by said feed mechanism for opening and closing said first switch, and a rotating control cam for opening and closing said second switch, said control means and said control cam being so constructed and so synchronized with one another that normally said first switch is opened when said pusher moves away from said support and said second switch is held closed by said control cam while said first switch is open, and said first switch is closed when said pusher moves toward said support to feed a blank thereon and said second switch is opened by said control cam while said first switch closed, and that when said pusher abnormally is prevented from moving toward said support at its normal time both of said switches are open simultaneously and said motor is stopped.

ii). A grinding machine in accordance with claim 1 wherein said grinder is rotatable on an aids transverse to said longitudinal support and spaced transversely from the axis of rotation of such blank and longitudinally from said support whereby the peripheral surface of said grinder grinds a point on such blank while such blank is rotated.

11. A grinding machine in accordance with claim 2 wherein said mechanism for moving such blank toward said grinder during grinding thereof comprises a stop for said advancing mechanism; means urging said advancing mechanism toward said grinder; and means for moving said stop towardsaid grinder.

12. A grinding machine in accordance with claim 11 wherein said stop comprises a stationary block having a longitudinal bore therein, and a tubular member threaded to said block in alignment with said bore; said advancing mechanism passing through said bore and said tubular member, and having a shoulder adapted to abut against said tubular member; said tubular member being rotatable in one direction to move from its initial position toward said grinder to release said advancing mechanism toward said grinder, and being rotatable in the opposite direction to restore said tubular member to its initial position; and wherein said means for moving said stop comprises a rack drivenby one of said cam members, a pinion driven by said rack, and means coupling said pinion withsaid tubular member for operating the latter.

13. A grinding machine in accordance with claim 2 wherein said mechanism for ejecting said blank from said grinding station comprises means cooperating with said advancing mechanism operable to strike said advancing mechanism a sharp longitudinally directed blow upon retraction of said grinder from said grinding station, to impel said blank from said support.

14. A grinding machine in accordance with claim 2, also comprising means coacting with said interlocked cam members and operable to start said rotary means upon introduction of a blank therein, and to stop said rotary means when grinding of said blank is finished.

15. A stylus grinding machine comprising, in combination, a longitudinally extending support for a blank to be ground; a pair of driven rolls located on opposite sides of said support and rotatable on longitudinally extending axes, said rolls having opposed peripheral surfaces passing close together and to said support for rotating such blank, said peripheral surfaces forming a throat therebetween; driving means for rotating said driven rolls around said longitudinally extending axes; a grinding wheel rotatable on an axis transverse to said longitudinal support and said longitudinal axes, said axis of said grinding wheel being spaced transversely from said .axes of said rolls and longitudinally from said support, said grinding wheel having the peripheral surface thereof passing through said throat in position to grind a point on such blank while such blank is rotated by said rolls.

16. A stylus grinding machine in accordance with claim 15, also comprising mechanism for advancing such blank toward said grinding wheel during the grinding of said point.

17. A stylus grinding machine in accordance with claim 16 wherein the axis of one of said rolls is tilted to urge such blank toward said last named mechanism, said machine also comprising means for driving one of said rolls at a greater peripheral speed than the other to hold said blank down on said support during grinding thereof.

18. A grinding machine comprising, in combination, a longitudinally extending support for a blank to be ground; a grinder at a grinding station adjacent one end of said support having a peripheral grinding surface extending across said support; advancing means for moving a blank along said support to said grinding station; means for rotating such blank on a fixed longitudinal axis at said grinding station; and means for moving such blank progressively further along said support during grinding thereof after initial contact with said grinding wheel.

19. A grinding machine in accordance with claim 18 wherein said last-named means for moving such blank progressively further along said support comprises a stationary block having a longitudinal bore therein; a tubular member threaded to said block in alignment with said bore; said advancing means passing through said bore and said tubular member, and having a shoulder adapted to abut against said tubular member; said tubular member being rotatable in one direction to move from its initial position toward said grinder, and being rotatable in the opposite direction to restore said tubular member to its initial position; and means urging said advancing means toward said grinder.

20. A grinding machine comprising, in combination, a longitudinally extending support for a blank to be ground; a grinding wheel adjacent one end of said support having a peripheral grinding surface extending across said support; a push rod movable in one direction for moving a blank along said support into contact with said peripheral grinding surface; means for withdrawing said g-rinding Wheel from its grinding position when grinding of said blank is finished; and means for moving said push rod in said same direction to eject said blank from said support after grinding thereof is finished.

21. A grinding machine comprising, in combination, a support for a blank to be ground; a pair of driven rolls rotatable on longitudinally extending axes, said rolls having opposed peripheral surfaces passing close together and forming a throat for receiving a blank to be rotated; driving means for rotating said driven rolls around said longitudinally extending axes; a grinding wheel rotatable on an axis transverse to and spaced transversely from said first-named axes, said grinding wheel having the peripheral surface thereof passing through said throat in position to grind such blank while such blank is rotated by said rolls.

JOHN F. PELTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,847,466 Binns Mar. 1, 1932 2,060,785 Binns et al Nov. 17, 1936 2,248,955 Capps July 15, 1941 2,475,091 Hackman July 5, 1949 20 2,477,730 Fouquet Aug. 2, 1949

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