US2012065A

US2012065A - Grinding machine

Info

Publication number: US2012065A
Application number: US458558A
Authority: US
Inventors: Frederick S Haas; Ralph L Goetzel
Original assignee: Cincinnati Grinders Inc
Current assignee: Cincinnati Grinders Inc
Priority date: 1930-05-31
Filing date: 1930-05-31
Publication date: 1935-08-20
Anticipated expiration: 1952-08-20

Description

Aug. 20, 1935. F. s. HAAS ET AL v GRINDING MACHINE l0 Sheets-Sheet 1 Filed May 31, 1930 7 d y w a. Z Z; I ,4.

. Aug. 20, 1935. I F. s. HAAS ETAL 2,012,065

GRINDING MACHINE Filed May 31, 1930 10 Sheets-heet 2 g Q w gm Denice; v

1935. R5. HAAS El AL 2,012,065

' GRINDING MACHINE Filed May 31, 1950 10 Sheets-Sheet 3 Zlwueniozi lllilllllmmlllllllllllllllllll'l un 'im m WMW' Aug. 20, 1935. F. s. HAAs AL GRINDING MACHINE 10 Sheets- Sheet 4 Filed May 31, 1950 Aug. 20, 1935. 5, s ETAL 2,012,065

GRINDING MACHINE Filed May 31, 1930 l0 Sheets-Sheet 5 V z m JWntozJ duommq Aug. 20, 1935. F. s. HAAS |-.-r AL GRINDING MACHINE Filed May 31, 19so 1o Sheets-Sheet e Ill: 21/

, 2 w a W w Aug. 20, 1935. F s, AAs r AL 2,012,065

GRINDING momma Filed May 31, 1950 10 Sheets-Sheet 7 Aug. 20, 1935. F. s. HAAS ETAL 2,012,065

GRINDING MACHINE Filed May 31, 1950 l0 Sheets-Sheet 8 W llfillllllllllllllll II ll ll Hlll I I I I I I I I I I I I I I I I I I I I I Aug. 20, 1935.

F. s. HAAS ET AL 2,012,065

GRI-NDING MACHINE Filed May 31, 1930 10 Sheets-Sheet 9 Swuantoz;

Aug. 20, 1935. 1F. 5. H A s AL GRINDING MACHINE Filed May 31 1950 10 sneaks-sheet 1o IVII/lIIIIIIIIIIIIIl/lflll/I/ I I 1 I n Patented Aug. 20, 1935 GRINDING MACHINE Frederick S. Haas, Cincinnati, and Ralph .L. Goetzel, Norwood, Ohio, assignors to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application May 31, 1939, Serial No. 458,558

18 Claims.

This invention relates to improvements in grinding machines and especially to improvements in such machines for operation on work pieces held between centers.

In the performance of grinding operations on work pieces held between centers there are two methods generally employed, in the first method the work piece is held between the centers on the table or supporting member which is then traversed across'the face of the grinding wheel to reduce the work piece throughout its length to the same size while in-the second method the supporting member, centers and work piece carried thereby are held stationary asrespects this traversing movement and the grinding wheel fed into the work piece for effecting a stock removal therefrom. In the former method of grinding the grinding wheel or tool is fed into the work piece at the end of each reciprocating stroke until the work piece is reduced to the desired size and the table is traversed between the increments of feeding.-

It is, therefore, one of the principal objects of the. present :;invention to provide a universal grinding machine that may be satisfactorily employed for performing either of the above men tioned methods of grinding- Another object of the invention is the .provision of improved means for actuating the several moveable members of the improved grind! ing machine in the most expeditious manner to eliminate all unnecessary movements and increase the production of the machine to the maximum.

Another object of the invention is the provision of improved means for effecting the translation of the work supporting memberwhile performing the grinding operation by traversing the work supportingtable and work across the face of the grinding wheel together with improved means for feeding the said grinding wheel or tool into the work at each end of the stroke of the table.

A further object ofthe invention 'isthe provision of improved means for actuating the grinding wheel or tool carriage relative to the bed and feed the tool into the work while the said work is being held stationary on its supporting table as respects the longitudinal movement thereof.

j .A' still further and specific object of the invention, is the provision of an improved grinding machine capable of performing universal grinding operations having the control and adjusting members vwithin convenient reach of the operator sa that the machine may be adjusted in a minimum of time and with the least inconvenience for the performing of the several methods of grinding.

Other objects and advantages of the present In the drawings:

Figure l is a front elevational view of a grinding machine embodying the improvements of this invention.

Figure 2 is an elevational view of the machine as seen from the right hand side thereof in Figure 1.

Figure 3 is a transverse sectional view taken on line 3--3 of Figure 1.

Figure 4 is a fragmentary sectional view taken on line 4-4 of Figure 1.

Figure 5 is a view of several parts shown in Figure 4, as seen from line 5-5 thereon.

Figure 6 is a sectional view taken on line 6-6 of Figure 4.

v Figure '7 is a sectional view taken on line 'I-l of Figure 6.

Figure 8 is a developed view showing the several positions of the actuating parts which effect the reciprocation of the work table as seen substantially from line 8 8 of Figure 1.- Figure 9 is a sectional view taken on line 9-9 of Figure 8.

Figure 10 is a sectional view taken on line HI- ID of Figure 8.

Figure 11 is a sectional view through the man- 'ual tool slide feeding means as seen from lineli-|l of Figure 1.

Figure 12 is a sectional view taken on line l2- l2 of Figure 1.

Figure 13 is a sectional view as seen fromline l3-'l3 of Figure 3.

Figure 14 is a sectional view taken on' line l4-l4 of Figure 3.

Figure 15 is a sectional view as seen from line I [5-45 of Figure 1.

Figure 16 is a sectional view taken on line I6l6 of Figure 11.

Figure 1'1 is a sectional view taken on line l'|-,-l1' of Figure 3 showing certain details of the operating structure.

Figure 18 is a view taken on line l8-l8 of Figure 1 showing the size control mechanism in elevation in operative engagement with the work piece.

Figure 19 is a view similar to Figure 18 showing the size controlling mechanism in an inoperative position.

Figure 20 is a longitudinal sectional view through the size controlling mechanism illustrating the internal mechanism thereof.

Figure 21 is a diagrammatic view illustrating the hydraulic and electric circuits involved in the control of the several moveable parts of this invention.

Figure 22 is a fragmentary sectional view taken on line 2222 of Figure 14.

Throughout the several views of the drawings similar reference characters are employed to denote the same or similar parts.

In general the improved grinding machine of this invention is semi-automatic in performanceand includes hydraulic and electric means for controlling the various movements of the machine. The machine includes the usual bed or support having mounted thereon a work supporting table reciprocable longitudinally of the length of the bed or support. Improved novel means for controlling and effecting the said reciprocation of the table are employed. In addition a tool slide operable transversely of the bed or support is controlled by improved novel electric and hydraulic means. The hydraulic and electric means for effecting the reciprocation of the table are interlocked with the movement of the tool slide toward and from the said table through an improved work piece size mechanism. The several movements of the table and tool slide are also under control of suitable handles or levers within convenient reach of the operator from his normal working position at the forward end of the machine. All of the foregoing mechanisms are clearly illustrated in the drawings and will be described in detail later.

Referring to the drawings and specifically to Figures 1, 2 and 3 there is disclosed is. bed or support 25 having formed longitudinally thereof at its forward end ways 26 and 21 for guiding during its reciprocating movement a work supporting table 28. Adjustably carried by the table at opposite ends thereof is the headstock 29 and tailstock 38 from which centers 3| and 32 respectively project. The centers 3| and 32 support a work piece 33 between them. The headstock 29 has a motor or prime-mover 34 connected through suitable transmission means enclosed within casing 35 with the spindle which carries the live center 3|. To effect rotation of the work piece 33 from the spindle or center 3| a dog 36 is secured to the work piece and bridged over by driving pin 31 to the said spindle. The work piece 33 is removed from between the centers 3| and 32 by retracting the said center 32 through the medium or handle 38 carried by the tailstock 30.

The table 28 and work 33 are reciprocated longitudinally of the bed while effecting a stock removal from the surface of the work throughout its length by a suitable tool or grinding wheel 39- supported by the bed for this purpose. To effect the said movement of the table 28 use is made of an hydraulic motor 40 disclosed in Figures 8 and 9. The motor 49 is rotated by an hydraulic medium in an hydraulic circuit which will be explained in detail later. The said motor 40 comprises gears 4| and 42 secured respectively toback gear shaft 43 and stub shaft 44. The stub shaft 44 is formed on its inner end with an enlarged head 45 having clutch teeth 46 for engagement with similar clutch teeth 41 on driv ing gear 48. The driving gear 48 is keyed or splined to driving shaft 49 and the said gear is, slidable relative to the said shaft 49 but rotatable therewith. The driving shaft 49 is journaled in anti-friction bearings mounted in the walls of gear box or bracket member 58 and has secured thereto or formed integral therewith intermediate to said anti-friction bearings a worm 5|. The worm 5| meshes with and drives a worm wheel 52 keyed or otherwise secured to vertical pinion shaft 53. This shaft 53 is journaled in anti-friction bearings carried by the bracket or housing and is connected by cap screws or the like 54 with a driving coupling 55. The driving coupling 55 is provided with a flange 56 through which the said cap screws 54 extend into a collar or flange 51 formed on the upper end of shaft 53 and the coupling 55 is splined to a pinion shaft 58 co-axial with the shaft 53. The pinion shaft 58 has integral therewith a pinion 59 having its teeth in mesh with the teeth of a rack 68 secured to the under surface of the table 28.

From the foregoing it will be noted that if gear 48 were shifted to engage its clutch teeth 41 with the clutch teeth 43 a direct driving connection between the hydraulic motor 49 and table 28 would be established to actuate the said table at its maximum rate. To effect the shifting of the gear 48 it is provided with a circumferential groove 6| receiving shifter pin 62 carried by one end of bell crank 63 pivoted at 64 to the bracket or housing 50. The other end of the bell crank 63 is bifurcated to provide

arms

65 and 66 receiving therebetween a pin 61 extending from a link 68. The link 68 is pinned or otherwise secured to a shaft 69 journaled in a sleeve 10 carried by the bracket 50. Secured to the outer end ,of the shaft 69 exterior of the housing 59 and within convenient reach of an operator is a {handle 1| whereby the shaft 69 may be rocked.

The handle 1| has four positions, the first of which is the shifting of the gear 48 to engage the clutch teeth 41 and 46 for effecting a rotation of pinion shaft 58 and pinion 59 and actuate the table at its maximum speed. The second position of the handle shifts the gear 48 to the position shown in Figure 8 at which time the clutch teeth 46 and 41 are out of engagement, and the gear 48 is in a neutral position to effect a complete stopping or non-movement of the said table 28. Continued movement of the handle H in a clockwise direction to its third position would mesh the teeth of the gear 48 with the teeth of a gear I2 pinned or otherwise secured to a shaft 13 journaled in anti-friction bearings carried by the walls of the bracket or housing 50. In this position the worm shaft 49 is rotated by manual means such as the hand wheel 14 mounted on the forward face of the bed or support 25. This rotation of the shaft 13 is effected through a pair of

bevel gears

15 and 16, the former being keyed or otherwise secured on the shafts 13, while the latter is pinned to a stud l1 journaled in the walls of the bracket or housing 50. Similarly pinned to the outer end of the stud I1 is a pinion 18 in mesh with a gear 19 secured by cap screws or the like 80 to the'hand wheel 14, the hand wheel 14 and gear 19 being mounted for rotation about a stud 8| carried by the bracket 58. The fourth or last position of the handle or lever II meshes the teeth of the gear 48 with a pinion 82 integral with or secured .to the shaft 43 of motor gear 4| of hydraulic motor 40 to effect the rotation of worm shaft 49 at a slower rate from the said hydraulic motor 40.

From this it will be seen that thtable 28 may be longitudinally actuated at differential speeds under power or the said table may be manually reciprocated. 7

As was noted above the motor 40 has the gears thereof rotated by an hydraulic medium under pressure. This hydraulic medium is normally contained within a tank 83 from which it is drawn through a conduit 84 by a pump 85 and discharged from the pump under pressure through a conduit 88. The medium then passes through a conduit 81 to starting and stopping valve 88 from which it passes through port 89 formed along the exterior valve sleeve 90 to a port 9| for direction. to the interior of the sleeve 90 passing then through port 92 to conduit 93 for conveyance to the directional control or reverse valve 94 which directs the medium to one side or the other of hydraulic motor 40. As shown in Figure 21, the medium passes through the conduit 95 from the valve 94 to the lower side of motor I 40. The spent medium discharged on the other side of the motor is directed through a conduit 99 back to the valve 94 for discharge through a conduit 91 to the sump or tank 83. The valve 88 in addition'to being used as a starting and stopping'valve controls the velocity' or rate at which the table 28 is being reciprocated and is of a unique, novel construction. This valve comprises a pair of spools 88a and 88b, each having.

a bore therein in axial alignment 1;? receive a spring 98 which tends to actuate the spools in opposite directions. The cannelure formed in spool 88b is utilized for connecting ports 9| and 92 formed in the sleeve 90 while the cannelure of spool 88a connects a pair of similar ports 99 and I00 formed in the said sleeve 90. The velocity or rate of movement of the table by the hydraulic motor is controlled more or less by closing off the port 99 by the shoulder IOI formed by the cannelure in' valve spool 88a.

As was noted above, the spring 98 tends to actuate the spools 88a and 88b in opposite directions or away from one another and thereby holds the said spools in engagement with adjustable stops I02 and I03 respectively, carried by a. pivotally mounted bell 'crank I04 and by an arm I05. The crank I04 is pivotally mounted at I06 to the bracket 'or housing 50 and has a second arm I01 extending therefrom The arm I01 of bell crank I04 is provided with a nose I08 contacting at all times with cam face I09 formed ona flange of sleeve III! journaled for rotation about a sleeve III. Secured to the outer end of the sleeve 0 is a handle I I2 having a spring pressed locking pawl cooperating with a serrated or toothed plate II3 secured to the cover of the bracket or housing 50-positioned on the forward face of the bed 25 within convenient electrically connected. From this it will be noted reach of the operator. Adjustment of the handle II2 rotates the sleeve II!) for adjusting the position of cam I09 to thereby shift the spool 88a and vary the opening of port I00 to control the flow of the hydraulic medium therethrough, As

shown in Figure 6, the port I00 is partly open to permit a normal shifting of the table so that the removal of stock from the work piece 33.

takes place at the desired-rate. I

While the flow of the medium through the port I00 is restricted during actualoperation of the machine, the flow from the port 89 formed longitudinally of the sleeve 90 is shut off by the spool valve 88b to stop the reciprocation of the table but an unrestricted fiow is permitted during actual operation. Asishown in Figure 6, ports 9I and 92 are connected permitting, as noted above, an unrestricted flow of the medium therethrough. This spool 88b is shifted by the arm I95 pivoted about pivot II4 carried by the rear wall of the bracket or housing 50. The upper end of arm I08 is pivotally connected to a longitudinally shiftable link I I5 which has its opposite end pivotally connected to smaller crank arm IIS pivotally carried by pivot I96. The other arm II1 of bell crank H6 is provided with a cam follower H8 at all times held in engagement with the stepped cam I I 9 formed on a flange I20 carried by the sleeve III; Pivotally secured to the outer endof the sleeve III is the main starting and stopping lever I2I which may be rocked in a clockwisedirection to shift the valve spool 88b and open port 9| to permit the table 28 to be actuated at a normal work feeding rate. From the foregoing it will be noted that handle II2 may be adjusted for positioning valve spool 88a to determine the rate of speed at which the work supporting table will be reciprocated. It will also be noted that with starting and stopping lever in its neutral or central position the flow of the hydraulic medium is restricted to stop the movement of the table while a shifting thereof to the right or in a clockwise direction will open port 9I and permit a flow ofthe medium there through determined by the setting of the valve spool 88a.

There are times when it is desirable to reciprocate the work table 28 at a high or rapid traverse rate, such as when grinding bearing portions at opposite ends of a shaft, for example, to thereby materially reduce the time involved in completing a given grinding operation. To this end the arm I01 of bell crank I04 is provided with a pin I22 in the path of movement of an abutment I23,

shown in Figure 4 as an adjustable screw, carried by a projection on flange I20 of sleeve III. Rotation of main starting and stopping lever I2I in a counter clockwise I00 and perspending speeding up of rotation of the pump gears to correspondingly rapidly rotate the pinion shaft 58 and reciprocate the table at a rapid rate.

The longitudinally shiftable bar I I5 has secured thereto a projection I24 abutting on opposite sides with adjacent ends of springs I25 and I29 through which depressible plungers I21 and I28 of stopping and starting switches I29 and I30 fare actuated to stop and start the headstock rotating motor 34 with which the said switches. are

that actuation of the lever I2I to effect reciproe cation of the table 28 simultaneously effects the rotation of the motor 34 and work piece 33 rotated thereby.

The directional control or reversing valve 94 is shifted at each end of the stroke of the table 28 to thereby reverse the movement of the table, To

this end the valve 94 is provided witha-shifter'.

rod I3I having a forked end and receiving be- I32 into an elongated perforation I36 formed in the upper end of one arm of bell crank I31. This bell crank I31 is pivoted at I38 and has its other arm I39 pivoted at I40 with one end of a link I4I. Carried by the bell crank I31 and projecting into the perforation I36 therein and from opposite sides thereof is a pair of set screws I42 and I43 adapted to engage with the pin I35 of lever I32.

The upper end of the link MI is pivotally connected to a crank arm I44 integral with a sleeve I45 journaled about a hollow shaft I46 supported by the bracket or housing 50. Keyed or otherwise secured to the outer end of sleeve I45 is a reversing lever I41 extending upwardly above the bed 25 and having a projection I48 extending therefrom toward the said bed 25. The table 28 has secured to its forward edge on opposite ends thereof dogs I49 and I50 adapted to engage the projection I46 for oscillating same about its axial center or hollow shaft I46.

At each end of the stroke of the table a slight pause is effected followed by a gradual increase in speed of movement of the table in the opposite direction. This pause iseffected by an hydraulic tarry valve enclosed within the casing I34. Vertically shiftable through the casing I34 is a pair of spool valves II and I52 having co-axial bores therein for a spring I53. The spool valve I5I is enclosed within a sleeve I54 through which ports I55 and I56 are formed. A cannelure I51 formed in the spool valve I5I connects the ports I55 and I56. The spool valve I52 is likewise enclosed in a sleeve I58 having ports I59 and I60 connected together by the passage I6I formed on the spool I52. The hydraulic medium under pressure is conveyed to the casing I34 through a conduit I62 coupled into the casing containing the reversing valve 94 and is in direct communication with the main pressure line 81. The spool valve I 52 is provided with a reduced portion I63 having formed at the end thereof a wedge shape head I64 having cam faces on opposite sides thereof. These cam faces cooperate with similar cam faces formed on the end of valve shifter lever I32. A pin I65 projects from the valve spool head I64 to which is attached one end of a spring I66 the other end of which spring is secured to a pin I61 projecting from the rear face of bell crank I31. Referring to Figure '7, it will be noted that port I55 of sleeve I54 is connected with port I60 of sleeve I 58 by a longitudinal port I68. Thechamber I69 formed between valve spools I 5| and I52 and their containing sleeves I54 and I58 is drained through a port I formed in the valve casing I34.

Assuming the table to be traveling to the left as seen in Figure 1, the dog I50, upon engagement with the projection I48 would rotate lever I41 and sleeve I45 which through the. crank I44 would depress link I4I. This depression of link I4I actuates the bell crank I31 in a counter clockwise direction to take up the lost motion between the pin I35 and abutment set screw I42 and at the same time through the interengagement of the contacting cam faces on the upper end of the bell crank with the cam face on head I64 forces upwardly the said head I64 and spool valve I52 permitting the hydraulic medium flowing through the conduit I62 to fill the passage I6I. By oscillating the bell crank I31 until the lost motion between the ends of set screws I42 and I43 is taken up the apex of the cam faces on the bell crank I31 is beyond the point of head I64. At this time the spring I66 which was tensioned by the raising of the head I64 tends to actuate the said head downwardly thereby bringing into engagement the opposite cam faces. This downward movement of the head and valve spool while freely moved upward is now restricted in its descent since it must force outwardly from the passage I6I the hydraulic medium therein. The medium is discharged through port I60 to port I68to the upper port I55 in sleeve I54. The flow of the medium through the port I55 is restricted by the shoulder on the valve I5I so that the descent of the head I64 and valve spool I52 is restricted and the shifting of the valve 94 takes place only at the rate of movement of the head. This movement gradually uncovers the port through which the hydraulic medium is passing to the hydraulic motor thereby slowly picking up speed to correspondingly slowly accelerate the speed of movement of the table 28.

The adjustment of spool valve I5I is obtained through cam face I1I formed on flange I12 of a sleeve I13 mounted for rotary movement about the sleeve I45. A cam follower I14 projects from the spool valve I5I in engagement with the cam I H being held in this engagement by the' spring I53. The sleeve I13 is adjusted by a handle I keyed or otherwise secured thereto andlocked in position by the interengagement of a spring pressed pawl I16 cooperating with a serrated or toothed plate I11. From this it Will be seen that the amount of tarry and rate of acceleration of movement of the table 28 after reversal may be adjusted to any desired limit.

The bed 25 has securedthereto behind the table 28 a plate or support I80 having formed thereon ways I8I and I82 extending transversely of the bed for guiding a tool carriage I83 for movement toward and from the table 26 and work carried thereby. J ournaled in the tool carriage I83 is a spindle I84 supporting for rotation therewith a grinding wheel 39. The grinding Wheel is substantially enclosed with a guard or housing I86 carried by the carriage I83 and moveable therewith. Depending from the carriage I83 and secured thereto by cap screws or the like I81 is a bracket I88 for a cylinder I89. Within the cylinder for movement relative thereto is a piston I90 having extending from opposite sides thereof hollow piston rods I9I and I92. The outer end I 93 of the piston rod I92 is provided with internal threads meshing with the threads of adjusting screw I94 journaled for rotative but not translative movement in the forward end I95 of intermediate plate or bracket I80. Keyed or otherwise secured to the screw I94 is a large gear I96 meshing with a pinion 214 keyed to rotate with a trigger or trip shaft 215 to be later described in detail. A relatively large gear 350 is keyed for rotation with the trigger or trip shaft 215 near its forward end and meshes .with a pinion I91 ,pinned or otherwise secured to one end of pinion shaft I98. A second pinion I99 is keyed to the shaft I98 near its other end and meshes with a similar pinion 200 on the end of shaft I rotatable through handle 202 carried by crank 203. A hand wheel 204 is journaled within a central boss of the crank 203 and keyed to the shaft 20I for movement therewith and has a driving connection with and relative to the crank 203 through a pinion 205 carried by the said crank 203. The teeth of the pinion 205 mesh with similar internal teeth 206 of an internal gear carried by the hand wheel 204. The pinion 205 has integral therewith a stud 201 journaled in a relatively small plate 208 pinned or otherwise secured in the crank 203 for movement therewith. To the outer end of the stud 201 is a spring pressedlocking pin 209 engage-' able in a plurality of holes formed around the plate 208.

From the foregoing it will be noted that by grasping handle 202 and rotating the crank 203 movement will be imparted to the hand wheel 204 which in turn rotates the pinion shaft 20I and through the transmission gearing, above noted, rotation is imparted to the screw I94 for adjusting the tool carriage l83, cylinder I89, piston I90 and parts associated therewith relative to the intermediate plate or support and relative to the adjusting screw I34. It will also be noted that by withdrawing the plunger 209 from the particular locking bore then engaged and advancing same to a different locking bore the stud 201 and pinion 205 will be rotated. The rotation of the pinion 205 will through the interengagement of its teeth with teeth of internal gear 206 additionally rotate the hand wheel 204 and pinion shaft 20I to further adjust the parts as above noted. The foregoing description deals with the manual means for initially setting up the machine for operation on a plurality of similar work pieces and for further adjusting the machine to take up for wheel wear to insure successive work pieces being reduced to the same size.

In the normal operation of the machine the tool carriage I83 is advanced toward and retracted from the work piece by an hydraulic medium under pressure. Means are provided for varyingthe rate of movement of thecarriage at a fast or rapid rate in both directions and additionally at a'slow rate in one direction. This slow movement of the carriage in the one direction may be either continuous as when performing a grinding operation by the plunge method or the said slow movement of the carriage may occm' intermittently as at the opposite ends of movement of the work table 28. Means are also provided for determining-whether the carriage will be actuated for plunge cut grinding or for intermittent feeding movement when operating on a cylindrical bar or shaft, for example.

In utilizing the power or hydraulic means for actuating the slide the hydraulic medium passes through aconduit 2I0 from the main pressure conduit 86 to ,a slide valve 2 from which it is directed to one sideor the other of piston I90. As shown in Figure 21, the mediumpasses from the valve sleeve 2 I2 through a conduit 2 I3 to the left hand side of the piston I 90 for actuating the carriage I83 toward the work supporting table. The valve 2 is initially shifted through its sleeve to initiate a movement of the grinding wheel carriage by a manually shiftable lever 2I4 pinned or otherwise secured on the end of the shaft 2 I5. The shaft 2 I 5 is journaled in the wall of a projection 2 I6 of bracket orhousing member 2 I1. On the inner end of the shaft 2 I 5 interiorly cf the projection 2I6 is a link 2I8 pivotally connected to a secondlink 2I9 having its other end pivotally connected to lever 220. The lever 220 is keyed to a hollow shaft 255 having an operable connection through a pin 253 projecting from a flange 254 on the hollow shaft 255 and an oscillatable plate 250 with a solid shaft I journaled for rotation within the said hollow shaft whereby said solid shaft is actuated. Depending from the solid shaft 25I is a short lever 222 having a forked end 223 received between adjustable abutments 225 fixed on the end of valve shifter rod 225.

By actuating the lever 2I4 in a counter clockwise direction or toward the operator the valve 2| l is shifted to the position shown in Figure 21,

to permit the hydraulic medium to pass through conduit 2I3 and actuate the grinding wheel carriage toward the work supporting table. This movement is at a rapid rate and the medium in the cylinder on the right hand side of piston I90 is being discharged through an unrestricted con-' duit 226 to the valve sleeve 2 I2 at which point the medium flows through a conduit 221 to the tank or sump 83. The movement of the carriage continues until the flow of the medium is inter-, rupted either by being completely out off or by being forced to pass through a restricted orifice.

As was noted above, the movement of the carriage either continues in a direct line-into the work at a relatively slow rateor it is fed toward the work at the completion of each longitudinal stroke of the work carrier. Considering first the continuous movement of the carriage in a straight line, as when performing a plunge cut grinding operation, the following mechanism is employed.

Mounted on the forwardface of the bed 25 in the housing 2I1 are various valves and control members each having a knob or control element positioned on the outside face of the box or bracket 2 I1. Referring now to Figure 1, the knob or control element in the upper left hand corner. indicated by the numeral 228- determines whether the carriage will be actuated toward the work feeding movement, and the knob 23I directly beneath the knob 230 adjusts the amount of feed of the wheel toward the table at the completion of each stroke of the reciprocating work table 28.

The knob 229 is pinned to a shaft 232 which 7 shaft is in turn pinned at 233 to a sleeve 234. The sleeve 234 has a sliding keyed connection as at 235 with a stud 236 of a worm screw 231. The stud 236 is adapted to be slidablyv actuated through the interior of the sleeve 234 without breaking the driving connection therebetweep. A spring 238 is interposed between the face, of the sleeve 233 and the end of the stud 236 tending to actuate the stud toward the right, as seen in Figure 3. This movement of the stud is restricted however, by a worm nut 238 threaded on the worm screw 231 having shoulders 240 formed at its opposite ends receiving therebetween the forked end 24 of lever 242. The lever ispivotally'mounted on a shaft 243'and restrained against movement by a spring 244 having one end connected to the lower end of the lever 242 and its other end secured to a lug 245 formed on the inner face of the bracket or housing 2 I1. A latch 246, see Figures 11'and 17, is secured to the shaft 243 having a ledge or step 241 thereon for a trigger 248. By actuating the knob or control member 220 in the proper direction the worm nut 239 may be actuated toward the front of the machine to thereby rotate the shaft 243 and actuate the trigger 248, as seen in Figure 11, in a counter clockwise di ection thereby shifting the ledge or seat 241 of the latch 246 relative to the end of trigger 248 so that the said trigger and latch overlapone another a predetermined amount,

the function of which will be explained in detail later.

The latch :46 is pivotally mounted betweeh the forked end 249 of the oscillatable plate 256 pinned or otherwise secured to the end of the shaft 25I. A spring pressed plunger 252 is carried by the plate 250 and bears against the latch 246 tending to rotate same in a counter clockwise direction about its pivot, as seen in Figure 11, for

holding the rear edge of the said latch against the seat formed by the forked end 249 of the plate 250. The plate 250 is further formed with anctch 252a receiving the pin 253 projecting from the flange 254 of the hollow shaft 255 in which the shaft 25I is rotatably journaled as above mentioned. Shiftable through the plate 250 adjacent the upper end thereof is a pin 256 abutting on one end the trigger 248 at a point on the other side of the pivot from the abutment of the plunger 252. The pin 252 on its other end engagesthe driving pin 253. The other end of the hollow shaft 255 has secured to it the arm 228 while the same end of the shaft 2 5I carries the arm 222 connected with the valve stem 225 for actuating the valve 2| I. A spring 251 is secured to the arm 228 and to a lug 258 extending inwardly from the front wall of bracket or housing 2 [1.

From the foregoing it will be noted thata push on the end of the worm screw 231 will cause stud 236 to be telescoped within the sleeve 234 carrying with it the worm nut 239 and through the shoulders or abutments 249 thereon a movement of lever 242 and shaft 243 in a counter clockwise direction. This rotation of shaft 243 moves the latch 246 away from-the trigger 248 whereupon step 259 of plate 268 secured to the bracket 2".

At the same time the movement of the plate 250 rocks 'the shaft 25I and valve shifter arm 222 connected thereto for shifting the valve 2 to the left, as seen in Figure 21, connecting the discharge port 262 in sleeve 2I2 through the cannelure 263 of valve 2H with the port 264 of a con- "duit 265. The conduit 285 extends to a valve chamber 266 controlled by the knob 228.

As was noted above'the knob or control member 228 is adapted to be adjusted or set to effect a continuous movement of the tool carriage I83 toward the work supporting tab 1e 28 or it may be set to permit an intermittent movement of the tool carriage toward the table, namely, at each end of the stroke of the table. As shown diagrammatically in Figure 21, the knob 228 is connected to a valve adjustable within the valve casing 266 to direct the flow of the medium through either of two ports 261 or. 268 formed therein; The setting of the valve here shown directs the flow-of the medium through a conduit 269 to a needle valve casing 210. This casing the work supporting table 28 untilthe grinding wheel 39 is positioned a predetermined amount Shaft.

from the work piece, which is controlled by the setting .of the trigger 248 relative to the ledge or seat 241 on latch 246, at which time the rate of movement of the grinding wheel into the work will be materially reduced. This changing of the rate of movement of the wheel is automatically effected by shifting the trigger from beneath the latch to permit a shifting of the valve 2 to the left to connect the discharge conduit 226 from the cylinder I89 with the conduit 265 through which the medium is controlled on its way to the tank or sump 83. r

.; The mechanism for automatically shifting the valve 2 comprises a bracket 213 in which is rotatably mounted the gear 214 slidably splined for rotative movement therewith but for axial movement relative to the shaft 215, which, for convenience has been termed a trigger or trip The outer end of the trip shaft 215 has an abutment 216 seated against the end of worm screw 231 having a splined portion 211 adjacent thereto receiving the driven gear of the hand adjustment transmission above indicated. Projecting from the other end of trip or trigger shaft 215 is a screw'218 threaded into a nut 219 fixed in a bracket 288 carried by the intermediate plate I80. One end of the nut 219 is counter bored and provided with internal threads receiving the external threads of a sleeve nut 28 I The nut 28I has a flange 282 formed on its outer end adapted to abut a shifter fork 283 depending from the cylinder bracket I88. A look nut 284 is threadedly carried by the sleeve nut 28I to lock the nut 219 and sleeve 28I in position relative one to the other so that the abutment flange 282 is fixed relative to the screw portion 218.

From this it will be seenthat as the tool carriage I83 is actuated toward the work table and work the shifter fork 283 carried thereby will engage with abutment flange 282 and shift the trip or trigger shaft 215 forwardly to actuate the worm screw 231 and stud 236 as above described, thereby shifting valve 2I I to the position to have the discharge from the opposite end of the cylinder wheel into the work to reduce the size thereof continues until the desired size is reached whereupon electromagnetic means are energized for shifting the valve to a neutral position and. stopping further movement of the wheel, this electromagnetic means and electrical interlock will be described in detail later.

The grinding wheel and carriage are now held stationary as far as any movement of them relative to the bed is concerned to permit a sparking out of the wheel and work and to permit the desired finish tobe had on the work. The handle 2 I4 is then manually actuated in a clockwise direction or toward the table 28 for shifting the valve 2I I to connect the pressure line 2 I9 through the valve 2 with the conduit 285 for directing the hydraulic medium under pressure into the conduit 226 to the right hand side of the piston I89 controlled. The movement of the I98 to retract the grinding wheel and carriage;

from the work and table. At this time the port 264 of conduit 265 is closed off to prevent any fidw of the medium therethrough. The movement of the carriage and wheel toward the rear of the bed or away from the Work and table continues until the other side 286 of the shifter fork 283 carried by the cylinder bracket I88 engages. with lock nuts 281 carried by sleeve nut 288 for shifting same. This sleeve nut 288 is threadedly carried by threaded portion 289 of a stop shaft 299 which moves with the nut 288. The shaft 290 is provided adjacent the threads 289 with a splined portion 29I for rotating therewith a gear 292. The gear 292 has a hub 293 forming the bearing for. rotation thereof which is journaled in the bracket 213', similarly to the mounting of the trigger or-trip shaft 215 and its gear 214. On the other side of the bracket 213 the shaft 290 has secured thereto for movement therewith a fork 294 yieldably mounted on the shaft by a spring 295 so that the fork may. give in the event of an obstruction or undue pressure being applied thereto. The lower end of the fork 294 is connected with avalve rod 291 extending from the rear of valve 2H for shifting the valve to a neutral position and stopping the rearward movement of the carriage I83.

From this it will be understood that actuation of the handle 2 54 will initiate a movement of. the grinding wheel carriage towardv the rear and through the interengagement of a shifter fork depending from the carriage with the stop shaft the said stop shaft will be shifted for correspondingly actuating the reverse valve and stopping the carriage.

As was noted above the foregoing description deals with the shifting of the grinding wheel and carriage continuously toward the work supportingtable and work at first at a rapid speed which is automatically reduced to a slow or feeding rate to feed the wheel into the work supported by the table. To actuate the grinding wheel toward the table to feed same into the work piece at each end of the stroke of the reciprocable table the knob 228 is .adjusted to open the port 268 andclose the port 261 of the valve casing 266. The grinding wheel and carriage are then actuated toward the table at a rapid rate in the same manner as described above by manually shifting the handle or lever 2I4 about its pivot toward the operator to shift the valve 2 to the position shown in Figure 21. This movement continues until, as above noted, the trigger shaft engages the worm screw to dislodge the latch from beneath the trigger when spring 251 will shift the valve 2| I to connect conduit 226 and port 262 with port 264 conduit 265 thereby directing the hydraulic medium discharged from the cylinder on the other side of the piston I90 into and through the conduit 265. At this time however, ,the hydraulic medium passes through valve casing 266 through port 268 to and through conduit 298 to a valve casing 299. The valve casing 299 encloses a shiftable valve 300 having cannelures 39I and 302. As shown in Figure 21, the hydraulic medium passes from the conduit 298 through port 303 into the sleeve 299 which port 303 is connected by cannelure 302 with a port 304 from which conduit 305 extends. This conduit 305 terminates at one end of shuttle valve casing 306 which encloses a shuttle valve 301. The casing 306 on the other side of valve 381 communicates through port 388 with a conduit 309 terv minating at its other end with port 3I0 in valve casing 299. This port M is connected through the cannelure 30I with a port 3 from which a conduit 3 I 2 extends for conveying the hydraulic medium back to the tank or sump 83. The grinding wheel carriage and grinding wheel are fed into the work an amount equal to the displacement of the hydraulic medium between the end of the valve 301 and the end of the casing 306. This distance is adjusted through the knob or control element 23I. In other words, the amount or volume of hydraulic medium displacedfrom the casing 306 by the valve 301. removes that amount of medium from the right hand side of piston I90 and permits the wheel to be fed into the work a distance corresponding to the said volume of oil displaced.

To reverse the valve 300 and consequently change the direction of flow of the medium through casing 299 and effect a shifting of the shuttle valve 301, the said valve 300 is coupled in with the hydraulic motor 40 so that upon each reversal of rotation of the motor the valve 300.

is reversely shifted through its casing. To this end a conduit 3I3 connects the right hand side of the casing 299 with the lower side of the motor 49, as seen in Figure 21, while a similar conduit 3I4 connects the opposite or left hand side of the casing 299 with the upper side 40 of the motor. Assuming now that if the pressure has been flowing from the directional "control or reverse valve 94 through the conduit 95 to actuate the motor 40 and a reversal of the valve takes place thereby introducing the medium under pressure through conduit 96 to the upper side of the motorthe medium will at the same time flow through the conduit 3I 4 to the left hand'side of the valve 300 and shift same to the right thereby connecting port 3I0 with 303 through the cannelure 30I and connecting port 304 with port 3I5 through the cannelure 302. At this time the hydraulic medium being discharged through conduit 298 will 'pass through the ports 303 and 3I0 through to conduit 309 and port 308 to the left hand side of shuttle valve 301 to shift same to the right thereby discharging the medium ahead of the valve out through the conduit 305, ports 304 and-3I5 through conduit 3I6 to discharge conduit 3I2 and at the same time permitting an infeed movement of the grinding wheel carriage I83 and grinding wheel 39. Again this intermittent feeding of the grinding wheel into the work will continue to take place at each end of the reciprocable stroke of the table until the work has been reduced to the desired size at which time the electromagnetic means come into play for again shifting the valve 2| I to the neutral position and stopping further movement of the wheel and carriage relative to the bed.

Associated with the tarry valve I34 and supported by the head I64 of spool valve I52 is a switch arm 3 I1. for closing a switch 3I8 normally held open during the longitudinal movement of the table but closed when the said table is stopped.

From this it will be seen that each time the table stops at the end of its recipro'cable movement before a reversal thereof is initiated the switch 3 I8 is closed. This switch is wired in series with a switch that controls the sizing of the work and which will now be described.

Mounted on the angularly extending guide ways 3l9 of the table is a base plate 320 secured thereto by any desirable means,'such as a clamp 32I. The plate 320 has projecting upwardly therefroma lug 322 through which an adjusting screw 323 extends. The threaded portion 324 of the screw is received in an internally threaded bore formed in pivot slide block 325. The slide block 325 has extending therefrom an ear 326 through which a pivot 321 extends for pivotally securing a casing or housing 328 thereto. Slidable through a bore 329 formed in the housing 328 is a; rack bar 330 being yieldably urged in one direction by a spring 33l abuttingit on one end. The other end of the spring 33I engages an adjustable abutment 332 for providing the proper tension on the spring 33L Meshing with the rack teeth of the bar 330 are the teeth of a gear 333 rotatable with 7 a shaft 334 journaled in the side walls of the casing 328. A pinion 335 also meshes with the gear 333 and is secured to a shaft 336 likewise journaled in the sides of the housing or casing 328 but extending beyond one side thereof. A finger or sizing arm 331 is secured to the said shaft 336 on its protruding end and has a contact point 338 riding on the surface of the work piece 33.

Referring to'Figure 20, the spring 33I tends to actuate the rack bar 330 toward the left thereby tending to rotate the gear 333 in a counter clockwise direction and through this gear to rotate the pinion 335, shaft 336 and gauging finger 331 in a clockwise direction. This holds the contact point 338 of the finger in engagement with the surface of the work piece which prevents further rotation of the parts just described and holds the spring 33! undertension. As the surface of the work piece is reduced the arm 331 gradually completes its revolution until the work piece has been reduced to the desired size at which time the point 338 of the arm 331 is clear of the surface and the spring expands to actuate the rack bar the limit of its movement.

At this time the contact point 339 carried by an upstanding lug 340 on the bar 330 engages the fixed contact 3 carried by the housing 328 to complete an electrical circuit. Thisswitch is wired in series with the switch 3I8 so that if the switch M8 is closed at the time of completion of the work piece to size an electrical circuit is complete for energizing a solenoid 342 mounted, see Figure 15, on the bracket 2 I1 and connected with the upper end of arm 22!] for shifting the valve 2! I to a neutral position and stopping further in-feed movement of the grinding wheel and its supporting carriage.

After the work piece has been-reduced to size and it is desired to replace the work piece on the table 28 the sizing device housing or casing from the pivot 321 to engage a laterally extending lug 344 on the rack bar 338 to retract the said rack bar and rotate the size arm 331 to the downward position shown in Figure 19. As soon as the work piece has been positioned the housing 328 is returned to the position shown in Figures 18 and 20 bringing the contact point of the arm 331 again into engagement'with the surface of the grinding wheel.

As was noted above, the switch 3l8 is closed whenever the work supporting table 28 is held in a stationary position or any movement thereof is interrupted so that the said switch is closed during the performance of a plunge cut grindin'g operation since the reciprocating table is locked against movement at this time and the switch is likewise closed at the time the reciprocating movement of the table is interrupt-edat each end of its stroke. Therefore, as soon as the work piece has been reduced to size during the performance of a plunge cut grinding operation the in-feed movement of the grinding wheel carriage and grinding wheel is immediately stopped. During the performance of a cylindrical grinding operation utilizing the reciprocation of..the work supporting table the switch M8 is normally open being only closed at the ends of the movement of the table. Now, should the work piece be reduced to size after the re- 'versal of the table the switch 3i8 would be open while the switch within the casing 328 would be closed and remain closed so that upon reaching the end of the stroke of the table in the other direction the closing of the switch 3"! would then complete the electrical circuit and actuate the solenoid 342 to stop the in-feed movement of the carriage and wheel.

In the operation of the machine various Sims of work pieces are adapted to be ground necessitating the adjustment of the grinding wheel and its carriage relative to the bed. This adjustment, as noted above, is obtained through the cross feed hand wheel 203 for actuating the cross feed screw I94. At the same time it is nec essary that the trigger shaft 215 and stop shaft 290 be adjusted as a unit with the adjustment of the said grinding wheel and carriage so that the trip mechanism will function at the desired point to change the rapid movement of the said carriage to the desired slow feeding movement. This is accomplished through the gears 214 and 292 'which mesh with the gear I96 on the screw I94 for simultaneously adjusting the

nuts

219 and 283 relative to the screw portions 218 and 289 respectively on the trigger and stop shafts. From this it will be seen that the zone of movement of the grinding wheel carriage under the influence of the hydraulic medium may be changed without disturbing the particular setting of the trip mechanism.

What is claimed is:

1. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a grinding wheel carriage carried by the bed and movable transversely threof toward and from the work-supporting table, hydraulic means for effecting the movement of the carriage including a reciprocating motor, an hydraulic medium for actuating the motor, means controlling the flow of the medium to actuate the carriage at a rapid rate, means controlling the flow of the medium for actuating the carriage at a slow rate, means operable by the position of the carriage for automatically operatively connecting one of the above mentioned means with the medium to automatically change the rate of movement of the carriage, and additional means independent of the position of the carriage for automatically shifting the valve to connect the medium with the other rate control means for automatically changing the rate of movement of the carriage.

2., In a grinding machine the combination of a bed, a grinding wheel carriage carried thereby and movable transversely thereof at a fast and a slow rate, an hydraulic reciprocating motor for effecting said movements, an hydraulic medium for actuating the motor, a. valve controlling the flow of the medium, manual means for initiating a movement of the carriage in reverse directions, automatic means for shifting the valve to change the rate of movement of the carriage from fast to slow in one direction, automatic means for shifting the valve to a neutral position to stop the movement of the carriage in the said one direction, and automatic means for shifting the valve to a neutral position to stop the movement of the carriage in the reverse direction.

3. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a grinding wheel carriage supported by the bed and movable transversely thereof toward and from the table, agrinding wheel supported by the carriage for effecting a stock removalfrom the work piece supported by the table, hydraulic means for effecting the said movement of the carriage includ ing an hydraulic medium under pressure, a conduit for the medium, a valve in the conduit controlling the flow of the medium and having a neutral position to stop the said flow and an operative position to permit the said flow, manual means for shifting the valve to its operative po sition, electromagnetic means for shifting the valve to its neutral position, and means carried by the table controlling the size of the work piece and electrically connected with the electromagnetic means for shifting the valve to the neutral position when the work piece has been reduced to the desired size.

4. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a grinding wheel carriage supported by the bed and movable transversely thereof toward and'from the table, a grinding wheel carried by the carriage for effecting a stock removal from the work piece supported by the table, an hydraulic reciprocating motor for effecting the said movement .of the grinding wheel carriage, an hydraulic medium for actuating the motor, a valve controlling the flow of the medium having a neutral position for stopping the said flow of the medium, an operative' position to permit an unrestricted flow of the medium to actuate the carriage at a rapid rate and an intermediate position for actuating the carriage at a slow feeding rate, manual means for shifting the valve to its operative position, restrained yieldable means released by movement of the carriage for shifting the valve to its intermediate position, and electro-magnetic means controlling the size of the work piece and operable to shift the valve to its neutral position upon reducing the work piece to its desired size.

5. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a grinding wheel carriage supported by the bed and movable transversely thereof toward and from the work supporting table, a grinding wheel supported by the carriage for effecting a stock removal from the work piece supported by the table, bydraulic means for efiecting the movement of the grinding wheel carriage comprising a cylinder carried by and movable with the carriage, a fixed piston within the cylinder, an hydraulic medium for actuating the cylinder relative to the piston, a valve controlling the flow of the medium having a neutral position for stopping the flow of the medium, an open position permitting an unrestricted flow of the medium and a movement of the carriage at a rapid rate, an intermediate position for restraining the flow of the medium and a movement of the carriage at a slow work feeding rate and a reverse position permitting an unrestricted flow of the medium and a rapid retraction of the carriage, and means automatically shiftable for adjusting the valve to its various positions including a pivotally mounted trigger having an operative connection with the valve, yielding means for actuating the trigger about its pivot, a latch controlling the movement of the trigger, and a trigger shaft slidably carried by the bed adapted to be actuated by the carriage for disengaging mitting a shifting of the valve from an .open position to its intermediate position under the influence of the yielding means.

' 6. In a grinding machine the combination of a bed, a work supporting table carried thereby hydraulic medium,

the trigger and latch perand translatable longitudinally thereof, a grinding wheel carriage supported by the bed and movable transversely thereof toward and from the worksupporting table, a grinding wheel supported by the carriage for eifecting a stock removal from the work piece supported by the table, hydraulic means for effecting the movement of the grinding wheel carriage comprising a'cylinder carried by and movable with the carriage, a fixed piston within the cylinder, an

hydraulic -medium for actuating the cylinder relative to the piston, a valve controlling the.flow I of the medium having a neutral position for stopping the flow of the medium, an open position permitting an unrestricted flow of the medium and a movement of the carriage at a rapid rate, an intermediate position for restraining the flow of the medium and a movement of the carriage at a slow work feeding rate and a reverse position permitting an unrestricted flow of the medium and a rapid retraction of the carriage, means automatically shiftable for adjusting the valve'to its various positions including a pivotally mounted trigger having an operative connection with the valve, yieldingmeans for actuating the trigger about its pivot, a latch controlling the movement of the trigger, a trigger shaft slidably,

carried by the bed adapted to be actuated by the carriage for disengaging the trigger and latch permitting a shifting of the valve from an open position toits intermediate position under the influence of the yieldingmeans, and a stop shaft slidably carried by the bed operatively connected with the valveand adapted to be slidably actuated by the carriage during its reversing movement for shifting the valve from a reverse position to its neutral position to stop the reverse movement of the carriage.

7. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool supporting carriage carried by the bed movable transversely thereof toward and from the work supporting table, hydraulic means for effectin the movement of said tool carriage including an a conduit for the medium, a valve in the cond thaving a neutral position, an open position, an intermediate position and a reversing position, mechanical means operable by the carriage for shifting the valve from an open position to an intermediate position for changing the rate of movement of the tool carriage from a rapid rate. to a slow one, electromagnetic means for shifting the valve to a neutral position when the work piece on the work supporting table has been reduced to the desired size, and mechanical means operable by the carriage for shifting the valve from a reverse position to a neutral one for stopping the reverse movement of the carriage.

8. In a grinding machine the combination of a bed, a work supporting table carried thereby and translatable longitudinally thereof, a tool supporting carriage carried by the bed movable transversely thereof toward and from the work supporting table, hydraulic means for eifecting hydraulic medium, a conduit for the medium, a valve in the conduit having 'a neutral position, an open position, an intermediate position and a reversing position, mechanical means operable by the carriage for shifting the valve from an open position to an intermediate position for changing the rate of movement of the tool carriage from the movement of said tool carriage including an a rapid rate to a slow one, electromagnetic means for shifting the valve to a neutral position when the work piece on the work supporting table has been reduced to the desired size, mechanical it means operable by the carriage for shifting the valve from a reverse position to a neutral one for stopping the reverse movement of the carriage, and means for varying the point at which the rapid movement of the carriage is changed to a. slow movement thereof.

l6 9. In a grinding machine the combination of a bed,'a work supporting table carried thereby and translatable longitudinally thereof, means for automatically reversing the translatory movement of the table, means for eifecting a slight tarry of the table at each reversal thereof, a tool carriage carriedby the bed and movable transversely thereof toward and from the table to effect a stock removal from the work piece supported by -the table, means for feeding the tool into the work piece at each reversal of the table, an electric switch associated with the tarry means and adapted to be closed at each reversal of the table, a sizing device controlling the size of the work piec supported by the table, an electric switch associated with the sizing device and adapted to be closed when the work piece has been reduced to the desired size, said switch being wired in series with the switch associated with the tarry means, and means in series with the electrical switches for stopping further feed of the tool carriage toward the work when the said switches are both closed.

10. In a grinding machine the combination of a bed, a translatable work supporting table carried thereby and movable longitudinally'thereof, a rotating tool carriage carried by the bed and movable transversely thereof toward the work supporting table to feed the tool carried thereby into the work, means for actuating the said tool 40 carriage including an hydraulic medium and a valve controlling the medium, electromagnetic means for actuating the valve to check the flow of the medium and stop further movement of the tool carriage, a housing carried by the work supporting table, a work piece size controlling mechanism carried by the housing including a rotatable shaft, yielding means tending to rotate the shaft, a feeler arm on the shaft having a contact point in engagement with the surface of the work piece, the said contact between the arm and. the work piece restraining the yielding means from rotating the shaft until the work piece has been reduced to the desired size, and

means closable by the yielding means when the 5 into the work, means for actuating the said tool carriage including an hydraulic medium and a valve controlling the medium, electromagnetic means for actuating the valve to check the flow of the medium and stop further movement of the tool carriage, a housing carried by the work supporting table, a work piece size controlling mechanism carried by the housing including a-rotatable shaft, yielding means tending to rotate the shaft,

a feeler armbn the shaft having a contact point A in engagement with the surface of the work piece, 1 the said contact between the arm and the work piece restraining the yielding means from rotating the shaft until the work piece has been reduced to the desired size, means closable by the yielding means when the work piece has been reduced to the desired size for completing an electrical circuit and energizing the electromagnetic means for actuating the valve to its stop position, and means pivotally securing the housing to the work supporting table whereby actuation of the housing about the pivotal mounting will position the feeler arm for proper engagement with a new work piece.

12. In a grinding machine of the class described the combination with a bed, of a grinding, wheel slide mounted thereon and movable transversely thereof, a work supporting table on the bed movable relative thereto, means for effecting the movement of said slide and table, means for reversing the movement of the table, means for determining the final size of the work being op-' erated upon, and an interlock between the table reversing means and the size indicating means for stopping further movement of the grinding wheel carriage when the work is reduced to the desired size.

13. In a grinding machine of the class described the combination with a bed, of a grinding wheel slide mounted thereon and movable transversely thereof, a work supporting table on the bed mov-' able relative thereto, means for effecting the movement of said slide and table, means for re-' versing the movement of the table, means for determining the final size of the work being operated upon, and an interlock between the table reversing means and the size indicating means for stopping further movement of the grinding wheel carriage when the work is reduced to the desired size, said means comprising an electrical control mechanism including a pair of switches one associated with the table reversing means and the other with the work sizing means.

14. In a grinding machine of the class described the combination witha bed, of a work supporting table mounted thereon for traversing movement relative thereto, ,a grinding wheel carriage mounted on the bed for movement toward the work supporting table to effect a stock removal from the work piece thereon, hydraulic means for effecting the movement of said table and grinding wheel carriage, each including a valve, means for shifting the table valve to reverse positions for effecting reverse translations of the table, means for shifting the carriage valve to a neutral posi-. tion for stopping the said carriage, means operable by the table for efl'ecting the movement of the table valve, a sizing device operable when the work reaches final size, and interlock means, associated with the sizing device and table valve actuating means to energize the carriage valve shifting means and thereby shift said valve to its neutral position and stop. further movement of the carriage.

15. In a grinding machine of the class described the combination with a bed, of a work supporting table mounted thereon for traversing movement rlativethereto, -a grinding wheel carriage mounted on the bed for movement toward the work supporting table to effect a,-stockremova1 from the work piece thereon, hydraulic means for effecting the movement of saidtable' and grinding wheel carriage, each including a valve,

means for shifting the table valve to reverse posh