US2899778A

US2899778A - Automatic grinding cycle

Info

Publication number: US2899778A
Authority: US
Priority date: 1959-01-20
Publication date: 1959-08-18
Anticipated expiration: 1976-08-18
Also published as: GB850203A

Description

R. E. BRlcKr-:R ET AL' 2,899,778

AUTOMATIC GRINDING CYCLE Aug.'l8, 1959 4 sheets-sheet 1 Filed Dec. 2l, 1956 /cKER auf? JR. G5551.

. `ATTORNEY Aug. 18, 1959 R. E. BRICKER ET AL vAUTOMATIC GRINDING CYCLE 4 SheeiS-Sheet 3 Filed Dec. 21, 1956 INVENTOR ROBERT E-BR/CKE BY WILL/HM P. FLD/'IR JR.

KURT M- G55 Af/f ATTORNEY United States Patent O AUTOMATIC GRINDING CYCLE Robert E. Bricker, William P. Flohr, Jr., and Kurt M.

Gebel, Waynesboro, Pa., assignors to Landis Tool Company, Waynesboro, Pa.

Application December 21, 1956, Serial No. 629,905

25 Claims. (Cl. 51-105) This invention relates to grinding machines particularly machines for grinding crankshafts or other workpieces having spaced shoulders which must be in alignment with the grinding wheel, or any workpieces on which the grinding operation is performed with only a transverse feeding movement between the grinding wheel and the workpiece.

It is an object of this invention to provide an automatic control of a grinding feed cycle along with the associated functions beginning after a workpiece has been placed in the machine and ending when the workpiece is removed from the machine. A further object is to provide a control for the grinding feed movement which will be effective to stop the feed after a predetermined rough grinding operation and then automatically resume the feed movement after a predetermined interval.

A further object is to provide means whereby the withdrawal of a work loading device after placing a workpiece in the machine, starts the grinding cycle.

A further object is to provide means whereby the last function performed after the workpiece has been ground to size provides a signal to a loading device to remove the workpiece from the machine.

Figure 1 is an end elevation of a crankpin grinding machine.

Figure 2 is an end elevation showing a combination work rest and caliper mounting.

Figure 3 is an end elevation of a portion of a crank loading mechanism.

Figure 4 is a hydraulic and electric diagram.

Number indicates the bed of the grinding machine. 11 is a wheelbase slidably mounted thereon. 12 is a rapid feed piston in a cylinder 13 and connected to wheelbase 11 through piston rod 14 and the depending member 15 on said wheelbase 11. A grinding wheel 20 is rotatably mounted on said wheelbase 11. The means for feeding the wheelbase 11 is substantially the same as that of Balsiger Reissue Patent 23,991, original Patent 2,638,719, granted May 19, 1953. A handwheel 21 maybe provided with suitable conventional connections for feeding the grinding wheel 20 manually.

A work carriage 30 is slidably mounted on said bed for movement parallel with the axis of said grinding wheel 20. A swivel table 31 is mounted on said carriage 30.

A pair of work driving heads 40, one of which is shown, are mounted on said table 31. On each of said heads is a clamping device comprising a cylinder 41 and a piston 42 slidably mounted in said cylinder 41. A pivotally mounted clamping arm 43 has one end connected to said piston 42 by means of a link 44. The other end of arm 43 is adapted to engage a workpiece and hold it on a bearing block 45. Said piston 42 is actuated by hydraulic pressure for clamping and by a spring 46 for unclamping.

Also mounted on said table 31 is a locating device described in detail in Patent 2,814,917, granted December 3, 1957. Said locating device consists of a housing 50 on which is rotatably mounted a vertical shaft 202 having suitable connections to actuate feelers 51 in opposite direc- ICCLA tions. Said locator is mounted in fixed predetermined relation to the grinding wheel so that when the feelers are moved outwardly, one may engage a shoulder before the other, in which case, the workpiece is moved by the first feeler until it engages the other at which time the work is properly located with relation with the grinding wheel.

A work rest comprising a main frame 60 is pivotally mounted on swivel table 31 at 61. Said work rest has suitable work engaging shoes (not shown) and is moved into and out of operative relation with workpiece W by a hydraulic motor comprising a cylinder 62 mounted on the front of bed 10 and a piston 63 slidably mounted in said cylinder. A piston rod 64 has a slotted member 65 on the upper end thereof which engages a stub shaft 66 on a tail portion 67 of said Work rest 60. The work rest is similar to that described in detail in said Reissue Patent 23,991.

Attached to said work rest 60 is a caliper consisting of a member 70 secured to the work rest frame 60. A pair of horizontally spaced springs 71 are attached at one end to member 70 and at the other end to an intermediate member 72. A pair of substantially vertical springs 73 connect member 72 with Work engaging member 74 of said caliper. These springs are preloaded or biased to hold member 74 against the work. Said work engaging member 74 has a pair of angularly spaced work engaging shoes 75 and 76. A nozzle 77 4is adjustably mounted in work engaging member 74. Attached to said nozzle 77 is a conduit `78 for conducting a supply of fluid under pressure to said nozzle 77. The conduit V78 is suspended from member 74 by a resilient member 79.

The means for placing unground workpieces in a machine and removing nished ground workpieces is shown in Figure 3. This apparatus has been described in detail in Patent 2,867,058, granted January 6, 1959. It will be described here briey in order to show the manner in which it co-operates in the cycle of operations described herein.

We are concerned here only with that portion of the apparatus which swings the workpiece downwardly into the machine and upwardly away from the machine. The apparatus consists of spaced up-right supporting members carrying a horizontal member 101 on which longitudinally spaced trucks 102 are mounted for a traversing movement thereon. Pivotally mounted on each truck 102 are pairs of spaced arms 103 and 104. The other ends of these arms 103 and 104 are attached to hook supporting members 105 at the lower end of which are hooks 106 for engaging a workpiece W. A cylinder 110 is pivotally mounted on a bracket 111 on said truck. A piston (not shown) in said cylinder 110 is actuated by suitable means to arm 103. A limit switch LS13 is mounted on truck 102 in the path of arm 103 in the upper position shown in dotted lines. The hook operating apparatus at the other end of horizontal member 101 is identical with that described above except that in the upper position of the hook supporting arm 103, limit switch LS14 is actuated The feed cycle begins when the transfer apparatus is in the right hand or loading position for loading a workpiece into the grinding machine. Y

Closing the start switch energizes ICR.

1CR1 completes a circuit from L1 to L1A which serves as a supply for all other circuits.

1CR2 provides a by-pass or holding circuit from L1A through the stop switch and around the start switch so that the grinding cycle described below will be repeated until the normally closed stop switch is opened.

21CR is energized at the end of each cycle through SLS or SPS in parallel circuits which combine in a single circuit throughY normally closed 5CR1 and normally closed HHZ.

3 `In the right hand or loading position of the "transfer apparatus, 21LS is closed to energize 25CR.

When the loader arms 105 on the transfer apparatus swing up after placing a workpiece in the machine, 13LS and 14LS areclosed -by the respective arms to complete a circuit through 25CR1 to energize 44CR.

44CR1and normally closed 59CR1 provide a circuit to energize 4CR. Y

A bypass or holding circuit around 59CR1-Apasses 'through normally closed 5CR3.

' Locator 4CR1 :and 4CR2 energize the locator valve solenoid B to` shift said valve to the left to direct uid under v pressure to the right end of locator cylinderl200 to shift piston 201 to the left and rotate vertical shaft 202 in a vclockwise'direction lto locate a workpiece. Shaft 202 shifts cam bar 203 to the right for rcam 204 to actuate SLS. Details of structure and operation of -this locator are disclosed in said Patent 2,814,917.

Operation of the locator opens SLS but 21CR is held by SPS which opens in response to pressure built up in the locator cylinder 200 to deenergize 21CR which, in turn, deenergizes clamp valve solenoid E.

Clamps The clamp valve is shifted by its spring to direct fluid under pressure to clamp cylinders 41 to actuate clamp arms 43 to clamp the workpiece W.

When moving to clamp position arms 43 close 1LS and 16LS to energize 59CR.

Normally closed 59CR1 in the circuit to 4CR is open. However, the circuit is held closed by normally .closed 5CR3.

The pressure required to close the clamps also closes SPS to energize SCR.

Locator reset Normally closed SCRS opens to deenergize 4CR to Vopen 4CR1 and 4CR2 to deenergize solenoid B to direct "'uid to the left end of cylinder 200 to reset the locator.

When the locator is retracted, cam 20S closes 6LS Work rest 15CR1 and 15CR2 open to deenergize Work rest valve solenoid A. In the deenergized position, said valve directs fluid under pressure to work rest cylinder' V62 to move piston 63 upwardly to move the work rest 60 and `sizing device caliper 74 about pivot 61 into operative engagement with workpiece W.

` Grinding feed resumed A cam 80 movable with piston 63 engages 3LS which fis'closed to energize 53CR.

which completes a circuit from L1A through 59CR2 and 5CR4 and normallyclosed 7CR1 to energize 6CR.

Work drive motor 6CR2 completes a circuit to energize HH which starts the headstock motor (not shown) to drive the workpiece W at grinding speed and opens normally closed HH2.

Starting the headstock motor closes plugging switch IPLS to energize 9CR.

9CR5 completes a circuit which includes previously closed ICRS, 9CR5, and 5CR6 and sparkout timer 6TR3 to energize 18CR.

Rapid infeed 18CR1 and 18CR2 energize the infeed valve solenoid C to advance the piston 12 and wheelbase 11 rapidly to operative position.

This movement of the wheelbase opens 4LS1 and closes 4LS2.

4LS2 energizes SCR.

SCRl provides a direct circuit from 59CR2 toV hold SCR and 8CR2 closes in the circuit to 7CR.

With 4LS1 open, 7CR remains deenergized untilv the Wheelbase is retracted.

At the end of the rapid feed movement, rapid feed jet pressure switch ZPS is closed by pressure built up when abutment 230 on feed piston 12 obstructs the ow of fluid from nozzle 231 to complete a circuit through normally closed 4PS to energize 11CR.

Fast grinding feed .11CR1 and 11CR2 energize fast feed valve solenoid Gto start the grinding feed shifting said valve to'the left-itc direct fluid lto the right hand ends of rapid feed 53CR1 closes a circuit from ZPS to 11CR to energize fast feed valve solenoid G to again direct fluid under pressure to cylinder 240 to resume the fast feed movementat the same speed or at a different speed.

Work to size and wheel retracted When a workpiece has been ground to size, a suitable Ysize-control device such as caliper 74 or a conventional timer or other suitable device opens normally closed 6TR3 and deenergizes ISCR and infeed valve solenoid C. Said infeed valve is reversed and directs fluid to retract the infeed piston 12 and grinding wheel 20.

When piston 12 is retracted, the ow of fluid from 'nozzle 231 is unrestricted. Pressure on ZPS drops-and ZPS opens `to deenergize 11CR to reset the fast feed piston 241 and retract grinding wheel 20.

Work rotation stop Retracting wheel support 11 ycloses l4I-.S1 and opens 4LS2 and completes a circuit through SCRZ to energize 7CR. Opening 4LS2 has no effect on SCR which lis held lby a circuit from 59CR2 through 8CR1.

Normally closed 7CR1 opens to deenergize GCR. vGGRZ opens to deenergize HH to stop the headstock motor. When the headstock motor stops, 1PLS opens to deenergize 9CR for the next cycle.

Normally closed HH2 inthe headstock motor relay closes to energize 21CR to open the clamps.

`2LS andlSLS close when clamps 43 open, energizing 32CR and swing down solenoid L to start the transfer cycle. t

At the end of the transfer cycle, when hooks are Aswung Yup after placing a workpiece in the machine, 13LS and 14LS are actuated to start another grinding cycle.

We. claim:

l. In a grinding machine for grinding cylindrical Workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a grinding wheel support movable transversely toward .and from said work support, a grinding Wheel rotatably mounted on said grinding wheel support, work loading means movable toward .and from said work support, a work locating device for locatingl the shoulders Vof the work piece in axial alignment with said grinding wheel, means responsive to said movement of said loader away from said Work supporting means for actuating said locator, clamping means for holding a workpiece onV said Work supporting means, means responsive to operation of 'said locator for actuating said clamping means to clamp a workpiece, a work drive motor for rotating said Work supporting means, means operable only after said clamps have been closed for starting said work drive motor, means for moving said wheel support toward and from grinding position, said means being operable-in response to rotation of said work drive motor, a work rest for supporting said workpiece during the grinding operation, a pressure switch operable at a predetermined point in said transverse movement for actuating said work rest, size control means operable at the end of the grinding operation to retract said grinding wheel support, a switch actuated by said retracting movement of said support for stopping said work rotating means, means operable after said work rotating means has stopped, to open said clamps, and switches actuated by openingsaid clamps for initiating operation of said loading means to remove aworkpiece from the machine.

2. In a grinding machine for grinding cylindrical workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a grinding wheel support movable transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, work loading means movable toward and from said work support, a Work locating device for locating the shoulders of the workpiece in axial alignment with said grinding wheel, means responsive to said movement of said loader away from said work supporting means for actuating said locator, clamping means for holding a workpiece on said work supporting means, means responsive to operation of said locator for actuating said clamping means to clamp a workpiece, means responsive to operation of said clamps for actuating said locator in the opposite direction for resetting, a work drive motor for rotating said work supporting means, means actuated by resetting said locator for starting said work drive motor, means for moving said wheel support toward and from grinding position, said means being operalble in response to rotation of said work drive motor, a work rest for supporting said workpiece during the grinding operation, a pressure switch operable at a predetermined point in said transverse movement, a timing device actuated by said pressure switch for actuating said work rest, size control means operable at the end of the grinding operation to retract said ygrinding Wheel support, a switch actuated by said retracting movement of said support for stopping said work rotating means, means operable after said work rotating means has stopped to open said clamps, and switches actuated by opening said clamps ffor initiating operation of said loading means to remove a workpiece from the machine.

3. In a grinding machine lfor grinding cylindrical workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a -grinding wheel support movable transversely toward and from said work support, a grinding wheel r0- tatably mounted on said grinding wheel support, work loading means movable toward and from said work support, a work locating device for locating the shoulders of the workpiece in axial alignment with said grinding wheel, means responsive to said movement of said loader afway from said work supporting means for actuating said locator.

4. In a grinding machine for grinding cylindrical workpieces, a bed, a carriage on said bed, a work support means mounted on said carriage, for rotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, a work locating device on said carriage and means for actuating same for locating the workpiece in predetermined axial alignment with said grinding wheel, clamping means for holding a workpiece in said work supporting means, a supply of fluid under pressure, and control means operated by said locator actuating means for directing said fluid under pressure rto actuate said clamping means.

5. In a grinding machine for grinding cylindrical worklpieces, a bed, a work support mounted thereon having means forrotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, a. work locating device and means for actuating same for locating the workpiece in predetermined axial alignment with said grinding wheel, clamping means for. holding a workpiece on said work supporting means, a supply of fluid under pressure, control means actuated by said locator for directing uid under pressure to actuate. said clamping means, and means responsive to operation of said clamps to reset said locator.

6. In a grinding machine for grinding cylindrical workpieces, a bed, a work support mountedthereon having means for rotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel vsupport slidably mounted on said bed for movement transversely toward and from said work support, a Igrinding wheel rotatably mounted on said grinding wheel support, a work'locating device and means for actuating same for locatingthe workpiece in predetermined axial alignment with said grinding wheel, clamping means for holding a workpiece on said work supporting means, a supply of uid under pressure, control means actuated by said 1ocator for directing uid under pressure to actuate said clamping means, means responsive tooperation of said clamps to reset said locator including a limit switch actuated by each of said clamps and connected in series, and a clamp pressure switch in parallel with said limit switches and connections between said limit switches and said locator whereby all said switches have to function in order to reset said locator.

7; In a grinding machinefor grinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supporting a Work-piece, a work drive motor for rotating said workpiece, a grinding Wheel support slidably mounted on said bed for movement trans- Vverselytoward and from'said work support, a grinding `wheelrotatably mounted Yon said grinding wheel support,

a work locating device and means for actuating same for locating the workpiece in predetermined axial alignment with said grinding wheel, means for retracting said locating device to inoperative position, and means actuated bysaid retracting movement for starting said work drive motor. 'p l v v 8. In a grinding machine for grinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supportingV a workpiece, a work drive motor for rotating said workpiece, a grinding wheel snpport slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, a work locating device and means for actuating same for locating the workpiece in predeterminedraxial alignment with said grinding wheel, means for retracting said locating device to inoperative position, and means to prevent operation of said work drive motor until said locating device is out of operative relation to the workpiece.

9. In a grinding machine for grinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatablysupporting a workpiece, a work drive Vmotor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for advancing said grinding wheel support at a rapid positioning rate, means for advancing said grinding wheel at a fast grinding rate, and` means operable at the end of said positioning movement for actuating said fast `grinding feed, means operable at a predetermined point in said fast grinding feed for stopping said feed -and starting a timing device, and means operable by said timer after a predetermined interval for resuming said grinding feed.

`7 10,.v In a grinding machine for grinding cylindrical workpieces, al bed, a work supportmounted'thereon having means for rotatablyY supporting a workpiece,V a Work drive motor for rotating said workpiece, a grinding wheel `vsupport slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel su-pport, means for advancing -said grinding wheel support -at` a rapid positioning rate, means for advancing said grinding wheel at a fast grinding rate, means operable .-at the end of said positioning -movement for actuating said fast grinding feed, means operable at a predetermined point in said fast grinding'feed forstopping said feed and starting a timing device, a steady rest, means for moving said steady rest towardV and from operative engagement 'with a'workpiece, said timer beingoperable to effect ,drive motor for rotating said workpiece, a grinding wheel 1 support slidably mounted on said bed for movement transversely toward and from said Work support, a grind- Ving wheel rotatably mounted on said grinding wheel support, means for advancing said grinding wheel support at a rapidv positioning rate, means lforV advancing said grinding wheel at a fast grinding rate, means operable .atthe end ofsaid'positioning movement for actuating said fast grinding feed, meansoperable at a predetermined point in said fast grinding feed for stopping said feed and starting a timing device, av caliper, means for Amoving saidcaliper toward and 'from operative engagement with a workpiece, said timer being operable to eifectoperation iof said caliper moving means to move said caliper to work engaging positionat the end of said predetermined interval.

.- 12.- In` av grinding machine-for grinding cylindrical workpieces, a bed, a work support mounted thereon having-means Vforrotatably supporting a workpiece, a work Vzdrive motor'for rotating said workpiece,v a-grinding wheel .support slidably mounted oni said bed for movement transversely toward and from said work support, a grinding-wheel rotatably mounted on said grinding wheel support, means for effecting said transverse movement of .said wheelsup-port for 'feeding said grinding'wheel against :the workpiece, means -for stopping said. movement at a predetermined-point in thefgrinding operation and for ysetting in operation a timing-device,v ay steady rest, means for moving said steady rest toward and from operative engagement with said workpiece, Ymeans operable by said timer after a predetermined interval to actuate said steady rest moving means, and means responsive to movement of said steady rest to cause resumption of said wheel feed.

13. Ina grinding machine for lgrinding cylindrical workpieces, a bed, a work support mounted thereon having means for'rotatably supporting a workpiece, a work drive motor for rotating-saidworkpiece, a grinding wheel support 'slidably mounted on said bed for movement transversely toward and from said work support, a'grindin'g wheel rotatably mounted on said grinding Wheel support, means for effecting said transverse movement of -said wheel support for feeding said grinding wheel against the workpiece, means for stopping said movement at a predetermined point in the grinding operation and for setting `in operation a timing device, a caliper, means for moving said caliper toward and from operative engagement'with said workpiece, means operable by said timer after a predetermined interval tol actuate said caliper moving means, and means responsive to'movement of said caliper to cause resumption of said wheel feed.

14. In a grinding machinefor grinding cylindrical workpieces, a` bed, a work support mounted thereon having means for rotatably supporting a workpiece, a work `drivetmotor for rotating said workpiece-a'` grinding'wheel support slidably mounted on said bed for movement transverselytoward and from said'w'ork support, a grinding wheel rotatably'mountedon said grinding wheel support, meansfor effecting said transverse movement of said wheel support for feeding saidgrinding wheel against the workpiece, means for stopping said movement ata predetermined point `in the grinding operation and Nfor setting in operation a timing device, a steady rest movable toward and from operative engagement with said workpiece, means operable by said timer after apredetermined interval to actuate said'steady rest, means responsive to movement of said steady rest to cause resumption ofsaid wheel feed,- means for retracting said wheelbase at the end of a grinding operation, and meansresponsive to said retracting movement to reset lsaid timer.

l5. In a grinding .f machine-for jgrinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel support -slidably mounted on said .bedv for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding Wheel support, means for eifecting said transverse Vmovement of said wheel support for feeding said grinding wheel against the workpiece, means for stopping said movement at a predetermined point in' thegrinding operation and for setting in operation a timing device, a steady rest movable toward and from operative engagement 'with said workpiece, means operable by said timer-after a predetermined intervalto actuate said steady rest, means responsive to movement of said steady rest to-cause resumption of said wheel feed, means for retracting said wheelbase at the end of aV grinding'operation, means responsive to said retracting movement to reset said timer, and means operable in response 'to the resetting ofv said timer to retract said steady rest.

16. In a grinding machine for grinding cylindrical workpieces, a bed, a work support thereon having means for rotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for effecting said transverse movement ofsaid wheel support for feeding said grinding Wheel against the workpiece, means for stopping said movement at a predetermined point in the grinding operation and for setting in operation a timing device, a 'caliper movable toward and from operative engagement with said workpiece, means operable by said timer after a predetermined interval to actuate said caliper, means responsive to movement of said caliper to cause resumption of said wheel feed, means for retracting said wheelbase at the end of a grinding operation, means responsive to said retracting movement to reset said timer, and means operable in response to the resetting of said timer to retract said caliper.

17. In a grinding machine for grinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supporting a workpiece, a Work drive motor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, a clamping device for holding a workpiece on said work support, a solenoid valve for directing fluid under pressure to said clamping device, means operable only after said clamping device is closed to start said work drive motor including a relay having a contact in the circuit to said solenoid valve, and means operable when said relay is deenergized to stop said work drive motor and to actuate said solenoid valve'to openthe clamps.

v18. In a lgrinding imachine forrgrinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supporting a workpiece, a work drive motor for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, a clamping device on said work support, means for opening and closing said clamping device to hold or release a workpiece, a loading device for placing a workpiece in said clamping device, means responsive to withdrawal of said loading device for starting a cycle of operations, means operable at the end of the grinding portion of said cycle for opening said clamps, and means responsive to opening said clamps including a limit switch to actuate said loading device to move into work removing position.

19. In a grinding machine for grinding cylindrical workpieces, a bed, a Work support mounted thereon having means for rotatably supporting a workpiece, a work drive motor' for rotating said workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for moving said grinding wheel toward and from operative position, an electric circuit for starting said work drive motor, a normally closed relay contact in said circuit, a limit switch actuated by forward movement of said wheel support for energizing a second relay, said second relay having a normally open contact in the circuit to said first mentioned relay, said limit switch having a contact in said lirst mentioned relay circuit, said contact being opened when the wheelbase is in operative position, said limit switch being operable by Withdrawal of said wheelbase to energize said first relay and through the normally closed contact of said rst relay to open the circuit to said motor starting relay.

20. In a grinding machine, a steady rest movable toward and away from operative relation with a workpiece, a caliper for measuring said workpiece comprising a work engaging member having angularly spaced work engaging shoes, an intermediate feeler member responsive to change in size of a workpiece, a bracket for attaching said caliper to said steady rest, an intermediate supporting member, spaced vertical resilient strips connecting said intermediate member and said work engaging member, and a pair of vertically spaced horizontal resilient strips for connecting said intermediate member and said bracket.

2l. In a grinding machine for grinding cylindrical workpieces, a bed, a work support mounted thereon having means for rotatably supporting a workpiece, a grinding wheel support slidably mounted on said bed for movement transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, means for moving said grinding wheel toward and from operative position, means for effecting said transverse movement of said wheel support for feeding said grinding wheel against a workpiece, means for stopping said movement at a predetermined point in the grinding operation and for setting in operation a timing device, a steady rest movable toward and from operative engagement with said workpiece, a caliper for measuring said workpiece, resilient means for supporting said caliper on said steady rest, and means operable by said timer after a predetermined interval to move said steady rest and said caliper into operative engagement with a workpiece.

22. ln a grinding machine for grinding cylindrical workpieces, a bed, a work support mounted thereon having means ,for rotatably supporting a workpiece, a grinding wheel support slidably mounted on said bed for' movement transversely toward and from said work, a grinding wheel rotatably mounted on said grinding wheel support, means for moving said grinding wheel toward and from operative position, means for eiiecting said transverse movement of said wheel support for feeding said grinding wheel against a workpiece, means for stopping said movement at a predetermined point in the grinding operation and for setting in operation a timing device, a steady rest movable toward and from operative engagement with said workpiece, a caliper for measuring said workpiece, resilient means for supporting said caliper on said steady rest, means operable by said timer after a predetermined interval to move said steady rest and said caliper into operative engagement with a workpiece and means responsive to movement of said steady rest to cause resumption of said wheel feed.

23. In a grinding machine for grinding cylindrical workpieces, particularly workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a grinding wheel support movable transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, work loading means for moving workpieces toward rand from said work support, a work locating device for eiecting alignment between a workpiece and said grinding wheel, clamping means for said workpiece, said means operating in a machining cycle for locating and clamping a workpiece and for machining the workpiece to a predetermined size, and means operable at the end of said machining cycle for starting movement of said Work loading means.

24. In a grinding machine for grinding cylindrical workpieces, particularly workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a grinding wheel support movable transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, work loading means for moving workpieces toward and from said Work support, a work locating device for electing alignment between a workpiece and said grinding wheel, clamping means for said workpieces, said means operating in a machining cycle for locating and clamping a workpiece and for machining the workpiece to a predetermined size, and means operable by said work loading means for starting said machining cycle.

25. In a grinding machine for grinding cylindrical workpieces, particularly workpieces having spaced shoulder portions, a bed, a work support thereon having means for rotatably supporting a workpiece, a grinding wheel support movable transversely toward and from said work support, a grinding wheel rotatably mounted on said grinding wheel support, work loading means for moving workpieces toward and from said work support, a work locating device for effecting alignment between a workpiece and said grinding wheel, clamping means for said workpiece, said means operating in a machining cycle for locating and clamping the workpiece to a predetermined size, means operable by said work loading means for starting said machining cycle, and means operable at the end of said machining cycle for starting movement of said work loading means.

References Cited in the file of this patent UNITED STATES PATENTS 2,638,719 Balsiger May 19, 1953 2,639,563 Swainey May 26, 1953 2,780,895 Silven Feb, l2. 1957