US2010347A - Grinding machine - Google Patents

Description

Aug. 6, 1935. J. E. cAsTl-:R 2,010,347

GRINDING MACHINE Filed sept. 2s, 195o s shetS-sneet 1 lili? 1 j JIS 116 Winn".

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.1. E. cAsTER GRINDING MACHI NE Aug. 6, 1935.

Filed Sept. 23. 1930 3 Sheets-Sheet 2 Aug. 6, 1935. J. E. cAsTER 2,010,347

GRINDING MACHINE Filed Sept. 23, 1930 3 Sheets-Sheet 3 lun" Y l am: n(

Patented Aug. 6, 1 93 UNITED STATES PATENT OFFICE GRINDING MACHINE John E. Caster, Cincinnati, Ohio, assignorjzo Cincinnati GrindersV Incorporated, Cincinnati, Ohio, a corporation of Ohio Application September-23, 1930, Serial No. 4832891 21 claims. (ol. sl-vz) This invention relates to improvements in machine tools and especially to improvements in automatic grinding machines.

One of the principal objects of the present invention is the provision of a grinding machine for performing grinding operations on `a plurality of diameters of a single work piece whereby the time for performing such grinding operations is reduced to a minimum and the production of the machine increased to the maximum.

Another object of the invention is the provision of improved means for actuating the grinding wheel carriage transversely of the supporting bed and automatically positioning said carriage relative to the succeeding diameters 'or steps of the work piece during the grinding operation.

Another object of the invention is the provision of improved means cooperating with the improved limiting means to insure the proper retraction of the grinding wheel carriage prior to the advancement of the work supporting table thereby preventing the grinding wheel gouging into the Work on its next infeed stroke.

Other objects and advantages of the present invention should be readily understood by reference to the following specification considered in conjunction .with the accompanying drawings and it is to be understood that any modiiications may be made in the exact structural details there shown and described within the scope of the appended claims without departing from or exceeding the spirit of the invention.

In the drawings:

Figure 1 is a front elevation of a grinding machine embodying the improvements of this in- Vention.

Figure 2 is a transverse sectional view through the machine taken substantially on line 2-2 of Figure 1.

Figure 3 is a sectional view taken substantially on line 3-3 of Figure 2.

Figure 4 is a fragmentary elevational view of certain of the parts shown in Figure 3 as seen from line 4--4 thereon.

Figure 5 is an enlarged fragmentary elevational View of certain parts shown in Figure 2 as seen from line 5-'5 thereon.

Figure 6 is a sectional view taken on line 6--6 of Figure 1.

Figure 7 is a diagrammatic view illustrating the hydraulic circuit employed with this invention.

Figure 8 is a sectional view through the abutment on the reversing lever forming a detail of the invention.

In the past considerable time has been consumed in grinding shafts having a. multiplicity of diameters, such as armature shafts and the like, and damage has resulted in that when advancing the parts relative to one' another accidental engagement between the wheel and work 5 took place resulting in the loss of the prior time spent thereon in previous machiing operations,

as well as holdups in assembly until replacement of the ruined part could be completed. This difficulty resulted chiefly from the noncontroll- 10 ability of the members of the machine tool organization which has been overcome by the device of this invention. In its broadest aspect this invention contemplates the provision of a grinding machine supporting in the usual manner a work piece having a plurality of diierent sized portions or diameters thereon cooperating with means corresponding to the work for positioning the work carrying member and tool carrying member relative to one another depending on the particular diameter in position for engagement with the grinding wheel.

One possible embodiment of the invention has been illustrated in the drawings in which the same or similar parts are referred to by the same or similar reference characters and the reference character I0 indicates the bed of a grinding machine having reciprocably mounted thereon a table I I supporting for movement therewith a headstock I2 and a tailstock I3. The headstock and 30 tailstock have extending from them work supporting means, such as the center I 4, between which the work piece I5 is positioned. The work piece I5, as will be seen in Figure 1, is provided with a plurality of different portions each of a different diameter which diameters are to be successively tooled or ground concentric to the axis of the work piece I5.

Any desirable means may be employed for advancing the table II step by step for positioning the different diameters of the work relative to the grinding wheel I6. As shown in Figure 2 the table I I is provided on its under surface with a rack II in engagement with rack pinion I8 carried by vertical shaft I9 rotatably journaled 45 in. bearing 20. A bevel gear 2| is secured to the' shaft I9 at its lowermost end and meshes with a similar bevel gear 22 on the end of shaft 23. Gear train or transmission chain 24 connects the shaft 23 with the shaft 25 of hand wheel 26. 50 From this it will be seen that rotation of the hand wheel 26 in a counter clockwise direction advances the table to the left, as seen in Figure 1.

To automatically actuate the said table resort may be had to the mechanism diagrammatically shown in Figure 7 which includes an hydraulic pressure source as the motive force. The hydraulic circuit here shown includes the pump 27 for drawing the hydraulic medium through suction conduit or pipe 28 from a tank or sump 29 mounted interiorlyof the bed I0. The hydraulic medium is discharged from the pump 21 through conduit 30 controlled by starting and stopping valve 3| for initially setting the machine in motion. A reversing valve 32 is interposed between the table actuating cylinder 33 and the starting and stopping valve 3| for directing the medium to the proper end of the said cylinder. A branch conduit 34 conveys the medium in the main pressure line to the valve 3| where, as shown in Figure '7, the reversing valve 32 directs the said pressure through conduit 35 to the right hand end of the cylinder 33. A piston 36 within this cylinder has a piston rod 3'! extending therefrom coupled through bracket 38 with the table I and the piston is actuated toward the left by the pressure from conduit 35. Thehydraulic medium within the cylinder 33 ahead of the piston 36 is discharged therefrom through conduit 39 to the reversing valve 32 where it is directed into discharge conduit 40 for return to the tank or sump 29. The said reversing valve 32 has extending therefrom a stem 4| having secured to it a shifter spool 42 receiving one end 43 of lever 44 which is suitably pivoted at 45 to a stationary part of the machine. The upper end of the lever 44 has a knob 46 for actuating the same and in addition has extending from it an abutment 41 which extends in the direction of the table Il. The said table is provided with a dog rail 41A to which are adjustably secured dogs 48 in position to engage the abutment 41 and actuate the lever 44 about its pivot 45. As many dogs 48 plus one are employed as there are diameters on the work piece being operated upon, each dog stopping the table at the necessary or desired point to present its diameter to the grinding wheel and the extra dog being utilized for positioning the grinding wheel to have its operative face trued. The lever abutment 47 is so constructed and mounted as to be actuated away from the bed I0 of the machine to clear the dog then engaging it whereupon the lever is then actuated about its pivot 45 in a clockwise direction to shift the valve 32 to the position shown in Figure '7 to initiate a movement of the work table to the left. After the movement of the table has been started the abutment is released and positioned in the path of movement of the next dog secured to the dog rail. Upon engagement of the succeeding dog with the abutment 41 the table is stopped and through additional mechanism the grinding wheel fed toward the work to reduce the same to the desired size by means later to be described.

' From the foregoing it will be noted that the work supporting table is advanced by power means from station to station to align succeeding steps on the work piece with the grinding wheel. It is to be understood that the dogs 48 are adjustable along the dog rail 47A to position them at the exact point corresponding to the different steps or diameters of the work so that when the grinding wheel is fed toward the work it will contact only with the intended diameter or step of the Work piece.

The grinding wheel I6 is secured to a spindle 48 rotatably journaled in a carriage 50 slidable on ways 5| which extend transversely of the bed for actuating the said carriage and wheel toward and from the Work. A nut 5|A is secured to a web 52 and bed l0, has `iournaled therein a sleeve 51.

of gear 58 which gear, through its sleeve, has a splined connection, as at 59, with the adjusting screw 53. Meshing with the gear 58 is a pinion 60 of compound gear 6| which has its larger gear 62 in turn meshing with a pinion 63 secured for movement with a cross feed shaft 64. The said cross feed shaft 84 is journaled at its rear end in bearing 65 carried by bracket 56 and has its forward end journaled in feed bracket 66 which encloses the feeding mechanism 61 terminating in manually actuable lever 68 and including the ratchet wheel 59. The ratchet wheel 69 is adapted to be rotated at a step by step rate by a pawl 'i0 operatively coupled with the mechanism 1| automatically actuable by the reciprocable movement of the table or by a portion of the table reciprocating mechanism as is well known to those conversant with this art as shown, for example, in Patent No. 1,672,177, issued to Einstein on June 5, 1928.

From this it will be seen that the adjusting screw 53 may be actuated manually or automatically for shifting the grinding wheel carriage 58 toward the wo-rk l5 to feed the said Wheel into the work and effect a stock removal therefrom. By reference to Figure l it will be noted that the pawl 'l0 is pivotally attached to its actuating mechanism and consequently may be thrown out of mesh with the ratchet in which position the pawl is placed at the completion of each grinding operation whereupon the manual lever 88 is actuated to effect a retraction of the wheel as will later appear.

The grinding wheel i6 and its carriage 50 are adapted to be retracted a considerable amount from the work when advancing the table I i from station to station and this movement is accomplished at a relatively rapid rate. As shown in Figure 2, the adjusting screw 53 is provided with a reduced portion 'l2 to which is secured piston 13 reciprocable through cylinder 'M formed interiorly of the bracket 55. The actuation of the piston 'i3 is most clearly shown in Figure 7 to which reference is now to be had. From this view it will be noted that this cylinder has extending from opposite ends thereof ports or conduits 'I5 and 16, the former connected by port or conduit i1 with the tank 29 while the latter is connected with branch pressure line 'i8 for feeding the piston i3 and parts connected therewith toward the work. A reversing valve 19 is interposed between the branch pressure and exhaust conduits 78 and Tl and the cylinder conduits or ports 'I5 and 'i6 whereby the coupling thereof is reversed for reversely actuating the piston 'I3 and grinding wheel carriage 50. 'Ihe piston I3 has formed on opposite sides thereof collars 8|] receivable in recesses 8| formed in the heads 82 and 83 of cylinder 74 which recesses are of a depth and diameter comparable with those of the collars 8l). The collars 80 and recesses 8| cooperate with one another to form dash-pots for cushioning the impact of the piston with the cylinder heads and each recess is drained through a restricted port 8|A. The outer cylinder. head 82 forms a sliding bearing for the extension 84 of the adjusting screw-piston rod 53 which extends beyond the said head 82 and is surrounded by suitable packing and the like 86 to prevent loss of pressure from cylinder 14.

The reversing valve 19 has extending from it a valve rod 86 slidably journaled in bearing 81 of housing or bracket 55. The bearing 81 has an end cap 88 for abutment screw 89 which limits the movement of the valve 19 in one direction. To shift the valve its stem 86 has a notch 90 formed in one side thereof receiving pin 9| extending from actuating arm 92 frictionally held on sleeve 93 by a spring 938L surrounding the sleeve and abutting the arm on one end and a nut on the other and the sleeve is loosely journaled on the extreme end of cross feed shaft 64. The sleeve 93 has extending from its flange a pin 94 adapted to be engaged by a pin 95 extending upwardly from the hub of cross feed pinion 63, as clearly shown in Figure 2. 'Ihe reversing valve 19 is provided with an internal bore 96 receiving a spring 91 abutting on one end with a shoulder 98 formed by the bore 96 and on the other end with an adjustable abutment 99 adjustably secured in head '|00 closing the reversing valve chamber.

From the foregoing it will be seen that in the rotation of the handle 68 or ratchet 69 of the cross feed mechanism in the proper direction to retract the grinding Wheel I6 and its carriage I1 from the position shown in Figure 2 a complete revolution of the said mechanism is necessary thereby backing the grinding wheel a definite di."- tance from the work. This actuation of the mechanism 61 carries the pin 95 fro-m one side of the pin 94 to the other side thereof at which time the arm 92 is actuated through the continued movement of. mechanism 61 for shftng the reversing valve 19 to connect the pressure conduit 18 with conduit 15, as seen in Figure 7, to retract the grinding wheel and its carriage at a rapid rate throughout the length of the cylinder 14. During the shifting of the valve 19 the spring 91 interiorly thereof was compressed or tensioned so that as soon as the handle 68 is again actuated to feed the grinding wheel toward the work the said spring expands for connecting the ports through the valve as shown in Figure 7. This causes an immediate plunge or in-feed of the grinding wheel to the position having a. space between its active face and the surface of the work represented by one nearly complete revolution of the handle 68 and in-feed mechanism 61. From thisit will be seen that themovement of the grinding wheel and its carriage to and from the work is accomplished ata rapid traverse rate without danger of gouging the work because a certain definite distance must still be taken up by the feeding mechanism before actual engagement between the wheel and work takes place. While one complete revolution of the hand lever 68 is necessary to shift the valve it is to be understood that this is not the limit of its movement and that two or more revolutions may be given the said lever without damage to any of the parts controlled thereby since the friction created by the spring 93n will permit a. slippage to occur between the arm 92 and the flange of sleeve 93. If however more than one revolution be given the hand lever in retracting the wheel head the same amount of reverse actuation must be given raid lever after the wheel head has been actuated toward the work by the hydraulic presure source to take up the increased space between the active face of the grinding wheel and the surface of the work.

For limiting the approach of and positioning the grinding wheel relative to the various steps or diameters of the work the adjusting screwpiston rod extension 12 has rotatably mounted thereon a. turret head having a'plurality of stops |02 adapted to successively engage a fixed stop |03 carried by the cylinder head 82. A3 shown in Figure 6, the adjustable stops |12 each comprise a screw member |04 having a knurled head |05 for the easy manipulation thereof and a knurled lock nut |06 Vfor securing the screw I Uli in adjusted position. The turret head I 0I is formed with peripheral gear teeth |06'L meshing with an elongated gear |01 fast on the end of shaft |08 journaled in a depending lug portion |09 of the cylinder head 82.

As the work supporting table is advanced to align successive portions or diameters of the work with the wheel the turret head |0| is correspondingly rotated about the axis of the piston extension 12 to align the desired adjustable stop |02 with the fixed s top |03. This movement of the turret head IOI is accomplished by a cam plate IIIl secured to the dog rail 41n having a series of cam faces III, each face representing one of the diameters of the work piece. As the table I I is advanced the cam faces I I I depress a yieldingly mounted plunger ||2 compressing or loading a spring |I3. The plunger I|2 is provided with rack teeth |I4 meshing with a gear |I5 secured to a shaft I6 journaled at its forward end in the housing I I9 which encloses the plunger and connecting gears. The rear end of the shaft II6 is journaled in a bracket |20 fixed to the rear face of the bed I6. A sprocket |2| is secured to the rear end of the transverse shaft II6 and has trained thcreabout a. sprocket chain |22 which likewise surrounds a sprocket |23 keyed to a sleeve |24 journaled on a stud |25 carried by the housing or bracket 55. A relatively large gear |26 is likewise keyed to the sleeve |24 and meshes with the pinion |21 fast on one end of shaft |03 whereby said shaft is rotated which rotation is imparted to the turret head I|| through the elongated gear |01.

From the foregoing it will be noted that as the work supporting table is advanced from station to station the turret head is correspondingly rotated to 'align the proper stop mechanism for limiting the approach of the grinding wheel to the work. This advance of the grinding wheel under infiuence of hydraulic pressure source takes place, as noted above, as soon as the cross feed mechansm is actuated in the'direction to feed the Wheel toward the work, so that after the wheel has been aga-'n advanced toward the work to the limit of its movement by the hydraulic pressure source the same space exists between the work and wheel as on the previous stop whereby unintentional or inadvertent engagement between the work and wheel can not take place and at the same time the relative actuation oi the ivvheel and work 'is accomphshed in a minimum of ime.

Should theidiameter of the work to be ground be of such asize as to preclude the retraction of the wheel and wheel head until the side of the piston 13 engages the cylinder head 82 without causing the grinding wheel carriage 50 to engage or tend to dislodge the housing or bracket 55 the following mechanism is employed. -The bracket member or housing 65 is provided with a tubular portion |28 receiving a plunger |29 having on one end a. head |30 and on the other end a wedge like 'cam face I3I. A spring |32 surrounds the plunger |29 abutting on one end vvith the head i3@ and on the other end with seat H33 formed interiorly of the tubular portion E28. The reversing valve stem il@ is provided with a slot i3d and an inclined cam face las for cooperation with the wedge like cam face isi. A pin i3@ extends from the head i3@ and is received in the bifurcated end lill of arm G33 of bell crank |139. This bell crank i139 is pivoted at Mill to the housing 56 and the other arm lill of bell crank its has an adjustable abutment M2 adapted to be positioned in the line of movement ofthe grinding wheel housing 5U so that when the said housing is retracted and engagement established therebetween, the bell crank i3d is'oscillated in a clockwise direc.- tion about the pivot Mit for depressing the plunger ld causing operative engagement between the tapered cam face itl thereon and the cam face i3d-of the valve stem 86 thereby retracting the said valve stem to a neutral position and stopping further movement of the grinding wheel housing and wheel. From this it will be seen that the movement of the grinding Wheel carriage and housing is at all times under control.

To retrue the active face of the grinding wheel i6 the tailstock i3 is provided with a bracket i153 for the trueing diamond Ml which is adjusted through the bracket M3 to place its active point beyond the largest diameter of the work piece l5. In order to position the turret head lill for trueing the face of the grinding wheel the housing lill has rotatably mounted therein a stub shaft H8 to which is secured a gear lll meshing with gear MI5 and rotating therewith. The stub shaft im is further provided with the handle lil@ so that a rotation of the said handle in the proper direction will position the trueing stop relative to the fixed Stop m3 and the work supporting table is translated to the desired position to align the trueing tool with the grinding wheel. It is to be understood that under normal working conditions a cam face lll is provided for automatically positioning the turret head for retrueing the active face of the wheel.

The operation of the machine should be readily understood from the foregoing description and it will be seen that an improved control mechanism for controlling the, cross feed movement of the grinding wheel and its carriage has been provided together with improved means for automatically positioning the grinding wheel relative to the succeeding diameters or steps of a work piece Which diameters are to be ground concentric to a given axis. It should be further evident that the operation of the machine reduces the time involved in nishing a given work piece to an absolute minimum increasing its production to a maximum.

What is claimed is: r

l. In a device of the class described, the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool carriage carried by the bed movable transversely thereof toward and from the work supporting table, hydraulic means for effecting the movement of the tool carriage, adjustable means for variably limiting the approach of the tool carriage to the work table, means for A effecting the translation of the work table and means operable by the table for positioning the tool carriage limiting means in accordance with the relative position of the table and tool carriage.

2. In a device of the class described, the combination of a bed, a work supporting table carried thereby and translatable longitudinally animee? thereof, a tool carriage carried by the bed movable transversely thereof toward and from the work supporting table, hydraulic means for effecting the movement of the tool carriage, adjustable means for variably limiting the approach 0f the tool carriage to the work table, means for effecting the translation of the work table, means Operable by the table for positioning the tool carriage limiting means relative to the position of the table, and additional means for advancing the tool carriage toward the work table independent of the hydraulic means.

3. In a device of the class described, the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool carriage carried by the bed and shiftable transversely thereof toward and from the work supporting table at a rapid traverse rate and a slow feeding rate, means for actuating the carriage at a feeding rate, means operable by the feeding means for effecting a rapid movement of the carriage, and a plurality of stops for variably limiting the movement of the carriage under the iniluence of the rapid moving means toward the work supporting table.

4. In a device of the class described, the combination of a be-d, a work supporting table carried thereby and translatable longitu-dinally thereof, an hydraulic pressure source, means connecting the pressure source with the table for effecting a movement thereof, a tool carriage carried by the bed and movable transversely thereof toward and from the Work supporting table, means connecting the pressure source with the tool carriage for effecting a movement thereof, and a plurality of stops positionable by the work supporting table for variably limiting the approach of the tool carriage to the table.

5. In a device of the class described, the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, an hydraulic pressure source, means connecting the pressure source with the table for effecting a movement thereof, a tool carriage carried by the bed and movable transversely thereoftoward and from the work supporting table, means connecting the pressure source with the tool carriage for effecting a movement thereof, a plurality of stops positionable by the work supporting table for variably limiting the approach of the tool carriage to the table, and means for advancing the tool carriage independent of the hydraulic actuation thereof.

6. In a grinding machine, the combination of a bed, a work supporting table carried thereby, a tool carriage carried by the bed, and means for effecting a movement of one of the parts relative to the other comprising an adjusting screw having a threa-ded connectiontherewith, a piston on the screw for axially shifting the screw and part, means for actuating the piston, a plurality of stops selectively positionable for engaging the part for variably limiting the movement thereof under the influence of the piston, and additional means for rotating the screw to additionally advance the part.

'7. In a grinding machine, the combination of a bed, a work supporting table carried thereby, a tool carriage carried by the bed, means for effecting a movement of one of the parts relative to the other comprising an adjusting screw having a threaded connection therewith, a piston on the screw for axially shifting the screw and part, means for actuating the piston, a plurality of stops selectively positionable for engaging the part for variably limiting the movement thereof un-der the infiuence of the piston, additional means for rotating the screw to additionally advance the part, and means for adjusting the position of the stops to variably relate the parts relative to one another by the piston. l

8. In a grinding machine, the combination of a bed, a tool carriage carried thereby and movable relative thereto, an adjusting screw having an operative oupling with the carriage, means supporting the screw for rotative movement and axial shifting, a piston on the screw, a cylinder y for the piston, means for actuating the'piston through the cylinder, and a plurality of means selectively positionable for limiting the movement of the piston through the cylinder in one direction.

9. In a grinding machine, the combination of a bed, a tool carriage carried thereby and movable relative thereto, an adjusting screw having an operative coupling with the carriage, means supporting the screw for rotative movement and axial shifting, a piston on the screw, a cylinder for the piston, means for actuating the piston through the cylinder, and means for limiting the movement of the piston through the cylinder in one direction, said means comprising an exteni sion on the adjusting screw, a turret head on the extension, and adjustable stops carried by the turret head adapted to engage a xed stop on the cylinder.

10. In a grinding machine for successively grinding individual portions of a work piece having a plurality of diameters or portions thereon the combination of a tool carriage, a work supporting table for the work piece, means for advancing the table from station to station to align the individual portions of the work piece with the tool carriage. means for shifting the carriage toward and from the work supporting table, independent means, one for each diameter or portion of the work, one for variably hunting said advancing movement of the tool carriage to provide a predetermined clearance between the tool carriage and each step of the work piece, and means for feeding the tool carriage into the work to effect the desired stock removal from the work.

11. In a grinding machine, the combination of a bed, a Work supporting table carried by the bed for translation relative thereto, means for advancing the table along the bed from station to station, means on the table conforming substantially to the contour of the work, a grinding wheel carriage carried by the bed and movable toward and from the work supporting table, a grinding wheel rotatably supported by the carriage, means for advancing the grinding wheel and carriage toward the work supporting table, and means operable by the work conforming means during the advance of the table for limiting the approach of the grinding wheel and table.

12. In a grinding machine for successively grinding individual portions or diameters of a work piece the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool carriage carried by the bed for movement transversely thereof toward and from the lwork table, means for translating the table, means'for actuating the tool carriage, a cam conforming to the contour of the work on the table, and means operable by the cam for limiting the approach of the tool carriage and work supporting table.

13. In a grinding machine for successively grinding individual portions or diameters of a work piece the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool carriage carried by the bed for movement transversely thereof toward and from the work table, means for translating the table, means for actuating the tool carriage, a cam conforming to the contourV oi' the work on the table, means operable by the cam for limiting the approach of the tool carriage and work supporting table, said means including a rack plunger, yielding means maintaining engagement between the plunger and cam, a transverse shaft operable by the plunger, and a stop .mechanism operable by the transverse shaft.

14. In a grinding machine for successively grinding individual portions or diameters of a work piece the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool carriage carried by the bed for movement transversely thereof toward and from the work table, means for translating the table, means for actuating the tool carriage, a cam conforming to the contour of the work on the table, means operable by the cam for limiting the approach of the tool carriage and work supporting table, said means including a rack plunger, yielding means maintaining engagement between the plunger and cam, a transverse shaft operable by the plunger, and a stop mechanism operable by the transverse shaft comprising a rotatable turret head, stop members carried thereby for engagement with a stop block on the bed, and a transmission mechanism between the transverse shaft and turret head for imparting the rotation of the transverse shaft to the head.

15. In a grinding machine for grinding successive diameters or portions of a work piece the combination of a bed, a work supporting table carried thereby and translatable -longitudinally thereof, a grinding Wheel carriage carried by the bed for movement transversely thereof toward and from the work, means for effecting said transverse movement of the grinding wheel carriage including a piston connected therewith, a cylinder for the piston, an hydraulic pressure source for actuating the piston through the cylinder, a valve in the connecting means, means for actuating the valve in one direction having a d enite lost motion movement prior to its engagement therewith, yielding means for shifting the valve simultaneously with the actuation of the valve moving means in the opposite direction, and means limiting movement of the piston in the direction of the table'.

16. In a grinding machine the combination of a bed, a work supporting table mounted thereon and translatable relative thereto, a tool carriage mounted on the bed for movement laterally thereof toward and from the work supporting table, inter-engageable means carried by the bed and carriage for limiting the movement of the carriage toward the table, the inter-engageable means carried by either the bed or carriage -being multiple in number for varying the approach of the carriage relative to the table, and means car-y ried by the bed and table co-operating with one another for determining which of the operative inter-engageable means is tobe effective.

17. In a grinding machinefor grinding 'individual portions or diameters of a multiple diameter work piece the combination of a bed, a translatable table carried by the bed and supporting the work piece for aligning the individual portions or diameters of the work with a tool, a

tool carriage on the bed movable laterally thereof toward and from the Work table, means for actuating the carriage at a rapid rate toward the table, and means automatically positionable upon movement of the table for stopping the tool carriage just short; of the particular diameter of the work in theline of movement of the carriage.

18. In a grinding machine for grinding individual portions or diameters of a multiple diameter work piece the combination of a bed, a translatable table carried by the bed and supporting the work piece, a tool carriage on the bed movable laterally thereof toward and from the Work table, means for actuating the carriage at a rapid rate toward the table, means automatically positlonable for stopping the tool carriage just short of the particular diameter of the Work in the line of movement of the carriage, and means carried by the table and bed co-operating to adjust the foregoing means in accordance with the particular portion of the work to be operated on.

19. In a grinding machine of the class described the combination of a bed, a Work supporting table mounted thereon and translatable relative thereto, a tool carriage mounted on the bed for movement laterally thereof toward and from the work supporting table, a xed stop carried by either the bed or tool carriage, a plurality of shiftable stops carried by the other member for engagement with the xed stop, hydraulic means for actuating the tool carriage to- Ward the work table and effecting inter-engagement of the stops, and means automatically adjusting the position of the shlitable stops to align the desired one with the xed stop.

20. In a grinding machine of the class described the combination of a bed, a work supporting table mounted thereon and translatable relative thereto, a tool carriage mounted on the bed for movement laterally thereof toward and from the work supporting table, a xed stop carried by either the bed or tool carriage, a plurality of shiftable stops carried by the other member for engagement with the fixed stop, hydraulic means for actuating the tool carriage toward the work table and effecting inter-engagement of the stops, means automatically adjusting the position of the shiftable stops to align the desired one with the fixed stop, and additional means for actuating the tool carriage toward the work table after the same is stopped by the inter-engageable stops.

21. In a grinding machine of the class described, the combination of a bed, a work support mounted thereon, a tool carriage mounted on the bed for movement toward and from the work support, means for actuating the tool carriage at rapid and slow speeds toward the tool carriage and selective means operable to stop the rapid movement of the tool carriage at a point depending on the size of the work to be operated upon.

JOHN E. CASTER.

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