US2641876A - Precision grinding machine - Google Patents

Description

June 16, 1953 DECKER Em 2,641,876

PRECISION GRINDING MACHINE Filed March 31, 1951 s sheetsws heep 2 INVENTORS 6 11003 020174! BJ'RNAJDAJH'ARJIN' June 16, 1953 J. DECKER ETAL 2,641,876

PRECISION GRINDING MACHINE Filed March 31, 1951 3 Sheets-Sheets Ill/(ID INVENTORS JA ca: Dian-x 2 By Bz'aNAR AJlium '2' 2421mm *WW A7701: Ys

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Patented June 16,1953 1 V r s I unrran QFFI E PREQISIQNEiiiZlG MACHINE Q (1 lielrnard Al earns, Qino innati,

ennli atism iia qh 3 1 1i9-Zl. fi

' I 2? 9. l-. 55 1 'rL u M il-i- [this invention relatls to improvements in A further object of the invention is the prognjiaehiiiesndhas in H r''ef tie visi nof an antor'natic compensating *inhafiisin mfte {qr effective to man-item thefiiistancebf 1* offthefoperative sgigrace of" the grinding when 5 viithre'speot'to the'sup p'ort determinedaxis' -of 'work piece substantialiy oon'stant i frespeetiv'e br wega-r or thegrin'ding Wheel.-

"fl'irthei objective ofthe invention is the pro- Vvi on of "imbroved' ci cle control" mechanism for brod idtmii grinding 'natzhin'es "vvhili will ng wheel are g en a relativ m i'iiinifiiiz'etheitime fa l i s q iaf M of the work 'ancigrin n w c} g t ve mov ment ng .h i x n ii a i iu l grindi f sl qete rninatioflo'f std k femovalf ii a diitonal bjeot of the present invention (is re ects 'eith e'r 't'ybe of operation it is con-' is the "provision 01? means under ontroP- f a ventlonal fthat'th're aa, retraction "'b e- 15 Work si' zingwr' gagina'meohainsm varf his! to fwe nith'iwoik iholiiih mechamifierid I the determine the "aniount' o'f"-re1-at ivertra ion of griiciinfg wiii 'e'l for jintrodiibtion arigi reinoval the vvorkandgr'i'miingvvfhee then/heel is s btjeot'to 1d rease effec provisioninconnectionwithadfiaI fed rate iii'oiinction grjmaing inachi'rfe' of aritomatie mans efi eclting reduction or chan'ge -m s'aid 'feed rates at a pointha ving flesriled relation to e operativsiir faee oftfieontt'ng elefn' "i- "An adiiitional "object of the ehtion is the I provision of improved"-Wheel vvear fiompensating ifieans' ivhieh'shall be eqeany ntilizab'l and- 'e'ffe'cjtivewhlether the inaeiiine i-s beiri "emplo ee for iinffeetfor for traverse -g'15indiing operatioiis *Qther ob j'eots d" advantages ofithe' present invention 5 on1dieadiiv a'ppar'entbvreferieno to 1th ollovving specification;considered in conjunction with the aecoiiipanying' drawings fforining apart thereof-fiend it i's'to lie -understood that ianvnrodifiations ifiavbe made*in"the-'-ex- "flee-seminar fcie'ta-iis' the're shown and described, 53 "with n the scope of the"'appen ied'-ciaims',- without-"departing rrdm ar extfe'ding t-he-=spi rit 'of the invention.

hamster Q r P1 2 on s, 9? i necessity r r intermittent trjuiiig T P groper shape and free kn tting" arac nrs h h h 10+ 1 h tsq i a ir q i on rap l a .pq ib a "9 fired i am re rem? B l a we work i $91495 its si im vempim 9 2 s "Figure l-is a front elevation of a grinding ma- 0 ohms mbodying the' presentinvention;" 4 V v h "of Figare-i; i gurefi'isa "detail elevational view of the compe'ns ory gmecnmsm and associated parts/ Figure f iS QaTragmentar elevation of the relativelwadjustable dia'iand'indicator elements. Fg'ii'r 5 is thediagramm'ati'eview-of one form ofhydraulie 'c'ircfiit for efiectingandcontrolling the oiei ation" "of the machine 'shown' -=in- Figure 1. t. 50 rryuF'gure 6 is a diagrammatic view illustrating the--struct1ira1 re1ationship-'-'and= functioning of the electrical control mebhanismr s the "diawings' thenume'ral 1 5 designates the 7 bed of a grindin'g machine having translatalgly inonnte'dih'ereon for'iongitudinal traverse the f2 is an expandedsectionaiview on the 7 carried by the bed unit 15.

table unit [5 bearing the suitably driven headstock I! and the tailstock 28, providing the centers l9 and respectively for determination of the axis of rotation of the work piece 2|.

Additionally, slidably supported by the bed 55 is a wheel head slide 22 bearing the grinding wheel 23. This slide is movable toward and away from the work piece position determined by the headstock and tailstock centers [9 and 20.

Suitably mounted on or formed as a part of the bed i5 is the cylinder block 23 having a first cylinder or chamber 24 in which is movable piston 25 coupled by rod 26 with depending portion 2'! of the wheel head slide 22. The block 23' is further provided with an additional cylinder or chamber 28 containing piston 28 having the piston rod 3% extending forwardly therefrom and formed with the screw thread portion 3| engaged in nut portion 32 of member 27.

The forward end of rod 39 is splined for relative axial sliding movement with respect to sleeve 33 carried by the stud shaft 34; suitably journaled in the bed 35 and bearing the drive gear 35. It will thus be evident that reciprocation of pistons 25 and 29 will effect a forward and rearward or advancing and retracting movement of the wheel head slide '22 while rotation of gear 35 and thus of screw 3! will vary the effective position of the wheel head for a given amount of movement of the piston 29.

The drive gear 35 is in mesh with pinion 56 on shaft 31 which is manually actuable as by the pilot Wheel assembly 38. This pilot wheel assembly includes a sleeve portion 39 providing a bearing 40 for the friction clutch unit 4%. The unit 4| is contained between flange 52 and gear 43, the latter being secured as a closure for the bearing 48 in opposition to flange 42, being retained in place as by the screws 44. The unit 4| includes a body portion having sockets or recesses at to receive springs 46 outwardly urging the friction plate 4? against gear 43. It will thus be seen that the unit 4! is mounted for rotation on the bearing 49 but frictionally engages respectively the flange 42 and gear 43 for rotative movement therewith. The unit 4| is further provided with the peripheral gear section 48 having meshing therewith gear 49 having a hub 58 journaled on the bearing sleeve 5| A second gear 52 has a sleeve hub 53 journaled on the left hand portion of the hub so that the gear 52 is rotatably mounted in juxtaposition to the gear 49 and correspondingly meshing with the gear 43. These gears together constitute a compensator unit.

The stud 5! has a tapered or clutch portion 54 adapted for interfitting engagement with the internal clutch face 55 of the sleeve 5c and a central aperture or bore 55 receiving the spring 5! reacting at one end on plug 58 and the opposite end on plunger 59, forcing the latter outward. This plunger reacts against the threaded plug 60 of control button 5| threaded into the left hand or forward end of sleeve 50 sothat the springreaction tends to retain gears 49 and 52 in a forward position, jointly meshing with the gear 48.

When it is desired to effect relative adjustment of the members 53 and 43 the button 6| may be pushed inwardly to move gear 42 out of mesh with gear 48 when the former may be given a relative rotational movement with respect to the gear 52, or alternatively slight additional movement will cause interengagement of the clutch faces 54 and 55 locking the member 52 against rotation so that relative face adjustment between the gears 49 and 52 may be effected by manual rotation of the gear 48 due to continued meshing engagement of the gear 52 therewith.

By reference to the drawings it will be evident that the cyclic relative movements of work support and grinding wheel support, in the present instance indicated as a movement of the grinding wheel head or slide, are hydraulically effected, the basic hydraulic circuit being particularly illustrated in Figure '5 while the controls for said cyclic and other movements of the machine are primarily electrical as indicated in the control circuit diagram, Figure 6.

Considering first the hydraulic power actuators, there is provided, suitably positioned as in the bed IS, the hydraulic reservoir 62 into which extends the intake 63 of pump 64 discharging into the pressure supply line 65. The pressure in the line and volumetric supply is controlled by relief valve to having return conduit 61 returning the excess discharge of pump 64 to reservoir 62, while a low pressure or return con- 'duit system 68. conducts the hydraulic medium back to the reservoir by way of the low pressure valve and filter unit 69.

In Figure 5 the hydraulic circuit control mechanisms have been indicated in the stop position and with the selector valve S in the manual control position. For effecting forward and reverse feeding, as distinguished from the rapid advance or retraction eifectable through the piston mechanisms 23 and 29, there has been provided a hydraulic motor 10 preferably of the rotary type having a drive gear H in constant mesh with gear 12 on worm shaft 13 carrying worm l4, driving the worm gear i5 on shaft 16. Splined and slidable on the shaft 76 is the reversing gear couplet Tl having a first gear l8 movable into 35 and thus screw Si in the opposite direction for retraction of the wheel head 22. The gears 18 and 19 are sufficiently spaced to be shiftable into an intermediate or non-engaging position as indicated in Figure 5. This centralized position is effected by the shifter 82 mounted on piston rod 8| supported by the centralizing bushings 82 and 82' having enlarged ends fitting respectively in the cylinders 88 and 84. If equal pressures exist in the cylinders 83 and 84, the centralizing bushings 82 and 82 will maintain the couplet 'il in the position illustrated. If, however, pressure .be maintained in either of these cylinders while the opposite cylinder is connected to reservoir or lower pressure, the piston rod and centralizing bushing will move under the influence of the higher pressure to one side or the other, alternatively meshing either 35-18 or 43l9 for transmitting rotation from motor 1!! to screw 3! Such a centralized position, dissociating the power motor drive from the screw 3!, leaving same solely under manually control has been indicated in Figure 5 where the selector lever 85 has been indicated in the manual position and setting of the throttles I I3 and I I4. As pressure exists in conduits 86 due to setting of handle 85 and its associate valve in the power position, pinion 19 will have been shifted to the right so that the rotation of the motor will act through gear 43, pinion 35 and gear 35 to rotate screw 3| in a direction simultaneously to eifect an advancing movement of the carriage 22 with respect to the piston rod 30. This operation will cause a clockwise movement of the gear 43 as viewed from the front of the machine, carrying with it the frictionally held compensator ll which has been so positioned during set-up of the machine that the rotation of the pin or abutment I46 will engage and depress the cam surface I4? of rock arm I48 pivoted to the bed I5 as at I49. This arm is connected by link we with the limit switch LS2 which normally holds the member I48 in raised position with the cam I41 extending into the path of movement of I46. Depression of the link by arcuate movement of the pin 146 will operateLSf, closing a circuit to energize the timer I56. This is of conventional type which may be set as desired by adjustment of the indicator ISI for functioning 'for example in from one second to 120 seconds interval for effecting deenergization of the solenoid D so that valve 98 may shift and eifect reverse or retracting movement of the wheelhead 22. The electrical control means, desired, may be so coupled with LS2 that at the time of its actuation CR4 and thus solenoid C will be deenergized, allowing valve M2 to close. Closing of valve I I2 shuts off the return flow from motor IE3 by way of I42, I46, and the coarse or rapid feed throttle valve H3 to the low pressure return line 68. When this takes place the return flow can then only be through branch $55 and the fine or finish feed throttle l I4, thus slowing down the rate of actuation of motor and consequently the rate of rotation of feed screw Alternatively, this deenergization of solenoid C may be placed under control of the gaging device plunger. As the work is reduced to its intermediate or coarse ground diameter, the movement of plunger lie completes a circuit, permitting the control switch CR-Z to open and deenergize solenoid Cv In the form of the invention shown in section in Figure 2, and in elevation, Figure 3, there has been shown as pivoted to the bed I5 a stop I54 urged into inoperative or disengaging position by plunger I55 actuated by spring l56. I

For effecting counterclockwise movement of the stop to move its terminal abutment portion I5! into the arcuate path of movement of the member I45, there has been provided the plunger I I6 coupled by conduit I58 with the valve I15. As previously described, during the initial portion of the cycle operation solenoid A isenergized, holding valve I I5 to the left so that its cannelure couples pressure line 85 through I58 to react on the piston plunger I I6 and move the same down-: ward, swinging the abutment I51 into operative position. When in this position, the abutment will contact and limit rotation of member I46 and thus of the frictionally driven compensatory member 4 I. In the initial set-up of the machine member I46 is preferably so adjusted as to just engage abutment I51 when the wheel head 22 has advanced the surface of the wheel to a point at which the rough or coarse grinding operation has been completed. Its movement, however, is absolutely a factor of the amount of feed rotation imparted to the screw 3I rather than a factor of the actual position of the operative surface of the grinding wheel 23 which, as previously mentioned, may in effect recede due to wear, truing operations or the like.

This particular mechanism has, therefore, been provided to compensate for such wheel wear in order that the retraction and forward feed to limit of coarse grinding may be automatically maintained substantially constant as to distance, thus reducing the cycle time involved and the additional unnecessary retraction and forward advance of the grinding Wheel accruing in the absence of such compensation.

- If the change from coarse to fine feed is under control of 'the sizing device the limit of fast rotational movement of the gear 52 in a clockwise direction will be increased or advanced as the wheel surface is reduced since additional rotative movement must be imparted to the feed screw to make up for the wheel face recession. The contact between I46 and I5? will in effect cause a counterclockwise slippage of the member 52 and a clockwise slippage of the compensator drive 4| as respects the actual drive mechanism for the screw. As the members 52 and 49 are jointly meshed with the gear portion 58 of the member 4| this will cause a counterclockwise movement of the pin I58 which is carried by the member49, movin it in a direction toward the cam surface I59 on rock arm I68 coupled by link IfiI with the operating element of the limit switch LSI.

LSI operates to deenergize solenoid B, coupling I37 to 68 as indicated in Figure 5,'thus releasing valve III which moves to the blocking position also indicated in Figure 5, closing off the return line from motor III to stop its rotation and thus the extent of feed retraction of wheel head 22 effected by rotation of the screw 3|. It will be evident that the closer pin I58 is to the point of actuating engagement for LSI the shorter the amount of reverse feeding effected by the member ill, and consequently the shorter the forward feed movement to be effected by said'motor during the grinding operation, or the less cutting of air during the operative portion of the feeding cycle. Since the reaction effect of stop I5! on pin I during the final feeding operation is to effect a counterclockwise movement of the pin I58 to compensate for any additional previous feed increment required to make up for wheel wear, it will'be evident that the construction in question maintains a substantially constant back and forth feed stroke of the wheel head as efifected by motor IE to compensate for wheel wear and maintain the time of the grinding cycle substantially constant. This effect is, of course, dependent on the relative positional adjustment of the members I46 and I58. To facilitate accurate positioning v during setting up of the machine for a particular cycle the sleeve member 53 is preferably provided with the graduations I52 for cooperation with the pointer or index mark I63 on the member BI, these graduations therefore serving to indicate definitely the relative arcuate adjustment of the parts and being preferably marked in graduations corresponding to each .0001 diameter of the work.

It will be understood that in some instances, as for example, in manual operation of the machine that the automatic power feed control is not desirable. To look out operation of motor I0 under these conditions the member I has been provided with the extension I 64 overlying the piston plunger I65 mounted in cylinder I66 carried by the bed I5. Normally, this plunger is held in deefiectab le by opening PSG-l.

plished by clockwise movement of lever T, couits automatic position as before andswitch' I99 closed to complete the infeed control-circuit, but

switch IE6 is adjustedto the without gage position shown in Figure 6.

The initiation of operation of the machine is as before in that closing of pressure switch PS energizes OR! to initiate the machine cycle. In

this instance, however, switch I96 has effected energization of control relay CR8, opening switch CR8-2 and closing switches CRB-l and CRii-B,

the supports is movable relative-to the other for eife'cting the grinding operation, said control CRii-l being connected to the timer TRi, to one selected interval closes TRl-l, picking up relay CR7, CRT-2 deenergizing CR2 and through CR2-5 solenoid D, effecting reverse or'rapid retraction of the grinding wheel slide 22. Dropping out relay CR2 closes switch CRZ-I, energizing CR3 and solenoid B, effecting reverse operation of feed screw 3| during the rapid retraction of slide 22 as previously described until CR3 is deenergized upon actuation of LS] by'pin I58. It will be noted that the compensator is equally effective in connection with this manner of operation but that the final grinding is effected as a sparking out rather than work size gaging operation. I By reference to Figure 6 it will be evident that moving switch I95 to break the upper blade Auto circuit will deener'gize the control circuit by way of CRIS-I, PSE-l, and in turn deenerglZeS CR-l. Closing the lower blade circuit Size and True of 95 energizes CRI3 to hold open the control circuit at CR I 3-I.

Temporary deenergization of the control circuit for CRi todrop out'the circuits controlled by it and reverse and stop the machine cycle is This is accompling pressure from 65 to PS4 as indicated in Figure 5.

What is claimed is:

1. Control mechanism for a precision grinding machine of the type including a work support, and a grinding wheel support in which one of the supports is movable relative to the other for effecting the grinding operation, said control mechanism including a reversible hydraulic motor coupled with one of the supports for movement thereof, an auxiliary uni-directional hydraulic motor, reverser means intervening said second motor and the support for effecting supplemental movements of the support, anda hydraulic actuating system including a reversing valve and conduits intervening the reversing valve, said first hydraulic motor and said reverser and power coumechanism including a reversible hydraulic motor coupled with one of the supports for movement thereof, an auxiliary uni-directional hydraulic motor, reverser means intervening said second motor and the support for effecting supplemental movements of the support, and a hydraulic actuating system including a reversing valve and conduits intervening the reversing valve, said first hydraulic motor and said reverser and power couplable by the reversing valve, said conduits including a first conduit system couplable by the reversing valvefor effecting one direction of actuation ofthe first motor and a corresponding actuation of the reverser, additional conduits al ternatively couplable by the reversing valve for effecting simultaneous opposite actuation of said first motor and said reverser, and additional valve means intervening the reversing valve and the reverser mechanism for determining the effective coupling of the parts.

3. Control mechanism for a precisionrinding machine of the type includinga work support, 7 and a grinding wheel support in which one of the supports is movable relative 'to the other for effecting the grinding operation, said control mechanism including a reversible hydraulic mctor coupled withone of the supports for movement thereof, an auxiliary uni-directional hydraulic motor, reverser means intervening said second motor and the support for effecting supplemental movements of the support, and a hydraulic actuating system including a reversing valve and conduits intervening the reversing valve, said first hydraulic motor and said reverser and power couplable by the reversing valve, said conduits including a first conduit system couplable by the reversin valve for effecting one direction of actuation of the first motor and a corresponding actuation of the reverser, additional conduits 7 machine of the type including a work support, and

a grinding wheel support in which one of the supports is movable relative to the other for effecting the grinding operation, said control mechanism including a reversible hydraulic motor coupled with one of the supports for movement thereof, an auxiliary uni-directional hydraulic motor, reverser means intervening said second motor'and the support for effecting supplemental movements of the support, and a hydraulic actuating systemv including a reversing valve and conduits intervening the reversing valve, said first hydraulic motor and said reverser and power couplable by the reversing valve, said conduits including a first conduit system couplable by the reversing valve for effecting one direction of actuation of the'first motor and a corresponding actuation of the reverser, additional conduits alternatively couplable by the reversing valve for effecting simultaneous opposite actuation of said first motor and said reverser, a rate control mechanism for the unidirectional motor including a fast rate throttle valve, a slow rate throttle valve, a selector valve for determining the effective cou- 9 pressed position by the spring pressed plunger I61. Coupled with the cylinder I66, however, at the lower end is conduit I68 coupled with the selector valve as indicated in the section C--C. When the selector valve is in the left hand or manual control position I68 is connected with pressure line 55, raising plunger I65 and thus rocking lever I60 for actuation of LSI to prevent energization of solenoid B for the motor release valve. When the selector lever is in its power position, IE8 is connected to the reservoir conduit system 68 so that the plunger I65 will remain in the position indicated in Figure 3.

The electrical control system The several electrical control relays, relay operated switchesand circuits, together with associate parts have been diagrammatically illustrated in Figure 6. Reference has been made to utilization of the lever T to effect actuation of the .preS- a sure switch 91 temporarily to close switch PS5-I to energize control relay CR I. For consideration of the automatic cycle of operation under gage control it is assumed that the Auto selector switch I95 has been manually closed, conditioning the-machine for automatic operation and the selector switch I96 likewise closed for gage Size control of the machine operation and the sizing gage placed in engagement with the work as shown in Figure 6, the unground workpiece 'maintaining the switch blades I 91 and I98 in raised position with reference to their respective control contacts 208 and 20l. With the machine so conditioned, the circuitwill be completed from "I05 on CR2-4 by way of switch I95, normally closed switch CR=I3-I, PS4-I and temporarily closed-switch 'PS5-I, normally closed CBS-4 and CRT-3 to the operating solenoid CRI, closin the series of switches CRI-I to CHI-5 operated thereby, the control relay being held energized through -CRI-5. Closing of "OBI-4 through normally closed CRT-2 energizes control relay CR2 which, in turn, through CR2-5 energizes solenoid D to eiiect forward rapid traverse movement of the grinding wheel while CR2 is locked by 'CR;23.

-At the same time CRI-2 by way of closed selector switch I99'in its Infeed position and normally 'closed s'witch CR5-2 energizes CR3 which'is then locked-byCRS-Q. n

CR3-3 energizes solenoid'B to shift valve In coupling pressure with conduit I31 to move valve I I I into open position, coupling actuating medium with motor 10 for actuation of feed screw 3'I so that the wheel carrying slide or ramZZ is now being advanced-toward thework bothby the rapid "traverse piston 29 and theaction "or motor'iu.

CR3-I through CRI-I eIIer'giZes CR5, which throughCRE-t activates solenoid A, -moving valve II5 to couple pressure 'to I58, depressing I I6 to move the compensator stop I51 upwardly as viewed in'Fi-gure 3 for engagement with pin I45. At the same-time, CR5-I 'by-way of OBI-3 completes the circuit to energize CR4 and CRlI-Z energizes solenoid C, shifting valveII8 to-couple pressure through I43 moving valve H2 down- 2 ward so that return conduit I42 from motor :10 is coupled 'With'the rapid'rate valve I I3, permitting the more rapid operation of motor 10. The rapidtraverse advance of slide 22-is terminated by engagement of-piston 2'9 with the endofits cylinder so that continued feed is efiected, solely this switch, opening switch LS2-I and closing CRI-I and CR5-2 to CR5.

10 LS2-2. the timer TRI and activates the circuit to CR8-I while interrupting one branch of the circuits from If there is no operation or too lon a delayed operation of the gage control circuit, timer TRI will function, interrupting the circuit through LS2 to stop the infeeding movement of the grinding wheel.

If, however, the machine is functioning in the normal manner by use of a suitable gaging mechanism, such as the two contact gage shown, for example, in Figure 6, the rapid feeding movement of the grinding wheel will cause a reduction in size of the work piece 2I until movement of plunger Iii) closes the circuit from I96 through contact 209,, energizing CR6 and signal light LT3. Energizing CR6 opens CBS-3, deenerg-iz- .i-n the control circuit for CR4 which opens to the position shown in Figure 6, deenergizing solenoid C to release the retaining pressure against valve H2 which closes, as indicated in Figure 5, so that all subsequent exhaust flow from motor 1!] must be through the slow feed rate valve I i4.

Energization of CR6 opens CRfi-I and as LSZ-I has already been opened, this deenerg'izes 'CR5., opening CRIJIL-S ,to deenergize solenoid A, releasing the compensator stop I54 whose inner end is then depressed or swung downwardly by spring 4-55 slit of the path of I46 so that member MS may have an added incremental movement during the .iinal :fine feeding for finish 'grindinglof the work piece :2 I

As the workreaches final size, .continuedidownward movement of the gage plunger -I I-0 closes circuit through switch member I 91 and contact 29 I to CR1, opening the normally closed switches CRT- 2, and CRL3, controlling respecitively'the energizationof .CR4,"CR2, and CR1 ,Release .of vCRZ-j 'drops or ,deenergizes solenoid D, releasing valve 9!] to reverse the -fiuid effect as respects piston 29 "so that the wheel head slide 22 is rapidly retracted by pressure againstthe forward face of piston 25. At the same time, :thepressure thus created in line 58 '89 ii111'ZSh/'SI;WitlI3ligearS 55, -18 for reverse rotation of o m was efiected Yb h' e oH'e'r-ation of motor'I-Ilf y t e umdlrvctmml he retractingeflect of motor :10 continues in its backing-01f or counterclockwise actuation of the feed screw until the pin .I.5,8 through link :6.I .actuates LSI. Opening -'of LSI Joy .way of CR'Z-I deenergizescontrol relay-CR3,,opening..the circuit through ..CR-3--3 to deenergize solenoid 3, allowing thehydraulic stop valve II I for supply line I 3'6 tormotorflfl to 'close, stopping the motor 'and'thus screw 3| .at-a point determined by the compensatory eiiected positioning of:the pin I58. will-thusbe seen thatratminimized retractive effectlis produced by'the motor v'lfland that irrespective .of the'diameter or wearing away oflthe operative surface-of the grinding wheel 23,ldue to the action of the gage and compensatory mechanism, a constant amount of rapid feed movement-willb e impartedto the grinding wheel in theproduction ofsuccessive work pieces. It is, of course, understoodthatthe rear-ward retraction of .the piston 29 continues to be efiected by the .pressure against;pistoni25-until the parts occupy theposition shown. in Figure 5 and the inanhinfelis conditioned; for initiation of a new yce 0 0 era ion-b e I handldT. p y movem nt of the starting In the'eventthat'it is desired toperform an automatic cycle of operation without utilization of a workgag-ingl device, switch I95 is, placed in Closing of LS2-2 initiates operation of first conduit system eovn'lable byti e reversing Controimechanieni ma h Q t e pe imiudin' wor @FPDDIT and a grinding wheel, support in; whic one qt the suppmjts is. movable neiatiye toth'e othei' jfor eff ing,,.the .grindin g' ope ation, sa'id oont ol me anism including a rever sipl e hydr anlic r'i iotor coupled with one of thesup lqox ts for 'ihovementthlereof an auxiliary uni, -:direc tiona1 I hydraulic motor, reverser means intervening said gecorid rnotoi and the support. fo fe t QQ Qm %-lmF ?QP oft hesu rt a da h d auli WWQUF FQ y including a reversing valve and eonduits inenvening the reversing valve, said fi et hydraulic m d s i r sn d POW?? qupl'ab eb the reversing Naive, s aid conduits including a,

.v'alvewfor .efiectingone direction qf, actuation of the first motor, and. a a corresponding eactnation of theireverseit, .zwlolitiona1 v eongiiiits .atltetnatiyely .couplable, by the reyersing yalye for effeeting simultaneous opposite 7 actuation jot said fir st motor and said reverser,v arate. vv OII HOL1 6 9;- \nism .forothe unidirectional motor including fast rate throttlevtalve, a..s1owlateuthrottlevalve, a selector valvevfor determining theeffective coublingjofjthe fast rate throttle with this return conduit fsystem, a by-pass tvalve positionable to effect a direct .co'uplingjof the motor return conduit to vexhaust,..and eontrol meari's for the bypassyalve, including a conduit ihterconnectin'g the .o I b'y-p'ass and reversing valves 'Whereby shiftingi'of the revers'ing valve eoupl'e'epr'essure to determine the positioning of the by-pas's valve.

The "'s'iew by the meter,

.A o i l im w and ge 4 m 'n, m an "m9t 2. f,s., he Wh l heard or b r eq h dr ulic 330W???- n r val v e i nb q for getting said tithing dew ioe an control fv l l fgfievice and. the gg n ljtrol for the. lvalve for determination "of the 'oper- Ajoontpoime'elian," S Q i tl id n ,9? ma I if r adtiiationjof the so cal conthemotdnfaiid s ewiiic e 11sec 1031 of 2 otiirhsaidi i means vpling of the hydraulic medium to the feed motor, said valve having a second position effective to revers the coupling to the rapid traverse motor while maintaining a power connection to the feed motor, independent valve means intervening said valve and the feed motor for determining the operation of the feed 'motor, a mechanical reverser intervening the feed motor and the wheel head for determining the direction of actuation of the wheel head by the motor, and hydraulic conduits intervening said first valve and the reverser for coupling pressure thereto variably to position the reverser in accordance with the positioning of said first valve.

14. Actuation and control means for the wheel head of a precision grinding machine, including a rapid traverse hydraulic motor and an aux-- iliary feed hydraulic motor, means connecting the respective motors to the wheel head for actuation thereof, a source of hydraulic actuating medium, and a control valve for the motors having a first operative position effective to couple the actuating medium to cause an advance movement of the rapid traverse motor and a coupling of the hydraulic medium to the feed motor, said valve having a second position eifective to reverse the coupling to the rapid traverse motor while maintaining a power connection to the feed motor, independent valve means intervening said valve and the feed motor for determining the operation of the feed motor, a mechanical reverser intervening the feed motor and the wheel head for determining the direction of actuation of the wheel head by the motor, hydraulic conduits intervening said first valve and the reverser for coupling pressure thereto variably to position the reverser in accordance with the positionings of said first valve, trip operable means for determining the position of the feed motor control valve, and a trip member movable with the wheel head for actuating said means to stop the operation of the feed motor.

15. Actuation and control means for the wheel head of a precision grinding machine, including a rapid traverse hydraulic motor and an auxiliary feed hydraulic motor, means connecting the respective motors to the wheel head for actuation thereof, a source of hydraulic actuating medium, and a control valve for the motors having a first operative position effective to couple the actuating medium to cause an advance movement of the rapid traverse motor and a coupling of the hydraulic medium to the feed motor, said valve having a second position effective to reverse the coupling to the rapid traverse motor while maintaining a power connection to the feed motor, independent valve means intervening said valve and the feed motor for determining the operation of the feed motor, a mechanical reverser intervening the feed motor and the wheel head for determining the direction of actuation of the wheel head by the motor, hydraulic conduits intervening said first valve and the reverser for coupling pressure thereto variably to position the reverser in accordance with the positionings of said first valve, trip operable means for determining the position of the feed motor control valve, a trip member movable with the wheel head for actuating said means to stop the operation of the feed motor, and an abutment engageable with the trip member upon advancing movement of the wheel head to eifect a com pensatory positioning of the trip member.

16. In a precision grinding machine having a translatable wheel head, means for effecting advancing and retracting movements of the wheel head including rotatable adjusting means, a motor for effecting rotation thereof, a trip operable stop device for determining the operation of the motor, and control means for said trip operable device including a pair of discs each provided with an abutment, a friction drive coupling the discs with the rotatable wheel head adjusting means to effect movement of the discs therewith While permitting controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs.

17. In a precision grinding machine having a translatable wheel head, means for effecting advancing and retracting movements of the wheel head including rotatable adjusting means, a motor for effecting rotation thereof, a trip operable stop device f-or determining the operation of the motor, control means for said trip operable device including a pair of discs each provided with an abutment, a friction drive coupling the discs with the rotatable wheel head adjusting means to effect movement of the discs therewith while permitting controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs, and means supporting the discs for relative movement whereby the phase relationship of the respective abutments on the discs may be varied.

18. In a precision grinding machine having a translatable Wheel head, means for effecting advancing and retracting movements of the wheel head including rotatable adjusting means, a motor for effecting rotation thereof, a trip operable stop device for determining the operation of the motor, control means for said trip operable device including a pair of discs each provided with an abutment, a friction drive coupling the discs with the rotatable wheel head adjusting means to effect movement of the discs therewith while permitting controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs, means supporting the discs for relative movement whereby the phase relationship of the respective abutments on the discs may be varied, a retractable stop, and means to project the stop into the path of movement of the abutment on one of the discs to limit the movement of the discs with the wheel drive mechanism to vary the angular phase relationship of the discs with respect to the wheel drive mechanism.

' 19. In a precision grinding machine having a translatable wheel head, means for effecting advancing and retracting movements of the wheel head including rotatable adjusting means, a motor for effecting rotation thereof, a trip operable stop device for determining the operation of the motor, control means for said trip operable device including a pair of discs each provided with an abutment, a friction drive coupling the discs with the rotatable wheel head adjusting means to effect movement of the discs therewith while permitting controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs, means supporting the discs for relative movement whereby the phase relationship of the respective abutments on the discs may be varied, a retractable stop, means to project the stop into the path of movement of the abutment on one of the discs to limit the movement of the discs with the wheel drive mechanism to vary the angular phase relationship of the discs with respect to the wheel drive mechanism, a trip device actuable by movement of one of said abutments, and means actithe valves in a position to move and hold the vatedby said trip device for effectingretraction Qfthe'stop'l 20. In a'precisiongrlnding machine having a translatable wheel head, means for effecting advancing'and retractingfmovements of the wheel head including 7 rotatable adjusting means, a

motor for fefi'ecting rotation thereof, a trip operable stop dev'icefor determininglthe operation of the in'otorjcontrol means for said trip operable device including a pair of discs each provided with an abutment ga friction drive coupling the discs with the rotatable wheelhead adjusting means to effect movement of the discs therewith while permitting/ controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs, means supporting the discs for relative movement whereby-the phase relationship of. the respective abutmentson thediscs may. be varied, a retractable stop, means toproiectithe stop into-the path of; movement-of the 'abutmentonone of the discs to-lim it the movement .of the discs with the wheel I, drive mechanism tovarya'the angular phase relationshipof the discs with respect to the wheel drive mechanism, a trip device actuable by movement of one of said abutments, means activated by said trip device for effecting retraction of the stop, a second trip device engageable by the'other abutment during reverse movement of said abut-- ment, and electric switch means coupled with said U trip and operable thereby for controlling the operation of the feed motor.

21. In a precision grinding machine having a translatable wheel head, means for effecting advancingand retractingmovements of the wheel head including rotatable adjustingmeans, a motor for effecting rotation thereof, a'trip operable stop device for determining the operation of the motor,

and control means for said trip operable device including a pair'o-f discs, each provided with an abutment, a friction drive coupling the discs with the rotatable wheel head adjusting means to effect movement of the discs therewith while permitting controlled slippage of the discs with respect thereto, said drive including elements insuring synchronous rotation of the discs, a pair of trip memrection determining valve for the first slide motor and independent rateand operation control valves for the auxiliary slide motor, means for biasing thevalves in a position to move and'hold the slide in retracted position, individually actuable solenoids for controlling the movement of the several valves from their initially biased positions, and

control means for said solenoids including an electric circuit embodying a reversing timer, a work sizing gage, serially arranged automatic cycle and infeed or traverse selector switchesan additional selector switclrfor completing the con-'- trol circuits inclusive-or exclusive of the sizing gage, and means for cyclically-controlling the activation'of the respective solenoids including control relays for the solenoids, a first limit switch having a portion operable in accordance with wheel head slide movements, asecond limit switchhaving a portion activatable during wheel head retraction, and a series of control relays having operating circuits interruptable by activation of the limit switches for determining the cyclic deactivation of the valve controlling solenoids.

24. A precision grinding machine including a translatable wheel head, a motor for effecting advance and retracting movements of the wheel headat a feed rate, and means for automatically debers respectively engageable, by the disc abut- V ments during their forward and reverse movements, an electric circuit including a switch member and a timer device coupled with one of said trip members whereby engagement of the abutv ment and trip will effect movement of said switch,

and a second control circuit including a switch and a feed motor stop valve control solenoidcoupled with the other of said trip members and actuable by the other disc abutment during the opposite direction of movement of the parts.

22. Actuation and control means for the Wheel head slide of a precision grinding machine including a first slide actuating motor and an auxiliary slide actuating motor, a series of control valves for the respective motors includingv a direction determining valve for the first slide motor and independent rate and operation control valves for the auxiliary slide motor, means for biasing slide in retracted position, individually actuable solenoids for controlling the movement'of the several valves from their initially biased positions, and control means for said solenoids including an electric circuit embodying a reversing timerya work sizing gage, serially arranged automatic cycle and infeed or traverse selector switches, and an additional selector switch for completing the termining the extent of retraction of the wheel headincluding a wheel head retraction "stop member movable in synchronism with the wheel head, a stop member presetting device including an interference abutment, a second abutment carried by the machine and projecting into the path of movement of the interference abutment as it is advanced in synchronism with the wheel head to limit the movement of said interference abutment, and means coupling the interference abutment and stop member whereby the eifective positioning of said retraction stop member is automatically adjusted by limitation of the movement of the interference abutment during advancing movement of the wheel head.

25, A precision grinding machine including a wheel head supporting a grinding wheel, means for effecting an advance and a retraction stroke of the wheel head at a feed rate, an advanceable and retractable stop coupled with the wheel head advancing and retracting means for movement in synchronism therewith and for movement relative thereto, means operable by the stop to limit the amount of the retraction stroke of the wheel head, and an abutment carried by the machine in position to react against the stop and limit the advance movement of the stop to change its phased relationship with respect to the wheel head advancing and retracting means whereby to reduce the retraction stroke to compensate for reduction in wheel diameter.

- 26. A precision grinding machine including a wheel head supporting a grinding wheel, means for effecting an advance and retraction stroke of the Wheel head at a feed rate, an advanceable and retractable retraction limiting stop frictionally coupled with the wheel head stroke effecting means for movement in synchronism therewith, the friction couple permitting relative movement between said means and said stop, means operable by the stop to limit the amount of retraction of 19 the wheel head, means to limit the advance movementv oi the stop only durin synchronized advance movement of the stop and wheel head whereby to change the phase relationship between the stop and wheel head, said means including an abutment coupled with the stop, and a second stop carried by the machine for engagement with said abutment means to limit the advance move ment of the retraction limiting stop, and additional presettable means to adjust the relationshipbetween the abutment means and the retraction limiting stop to vary the length of stroke of the wheel head effected by the Wheel head shifting means. l

27. A precision grinding machine including a wheel head supporting a grinding wheel, means for effecting an advance and a retraction stroke of the wheel head at a feed rate, an advanceable and retractable stop coupled with the wheel head advancing and retracting means for movement in synchronism therewith and for movement relative thereto, means operable by the stop to limit the amount of the retraction stroke of the wheel 20 head, an abutment carried by the machine in position to react against the stop and limit the ad- Vance movement of the stop to change its phased relationship with respect to the Wheel head advancing and retracting means whereby to reduce the retraction stroke to compensate for reduction in wheel diameter, and a workengagingsizing device coupled with the wheel head stroke effecting means for effecting retraction of the wheel head and the retraction limiting stop.

' JACOB DECKER;

BERNARD A. KEARNS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name I Date 1,911,553 Cole et a1 May 30, 1933 2,092,876 Cramer Sept. 14, 1937 2,241,634 Decker May-13, 1941 2,280,692 Elberty Apr.'21, 1942 2,376,237 Decker et a1 May 15, 1945 2,429,830 Ljunggren -Oct. 28,1947 2,584,499 Pyne Feb. 5, 1952

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