US2344242A

US2344242A - External-internal cylindrical grinding machine

Info

Publication number: US2344242A
Application number: US438091A
Authority: US
Inventors: Carl G Flygare; Herbert A Silven
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1942-04-08
Filing date: 1942-04-08
Publication date: 1944-03-14
Anticipated expiration: 1961-03-14

Description

March 1944- 'c. e. FLYGARE El'AL 2,344,242

EXTERNAL-INTERNAL CYLINDRICAL GRINDING MACHINE Filed April 8, 1942 5 Sheets-Sheet 1 EE 1 \N grwwvkvld EARL G. F LYG'ARE HERBER T A. Sn. VEN

March 14', 1944- c. s. FLYGARE El'AL 2,344,242

' EXTERNAL-INTERNAL CYLINDRICAL GRINDING MACHINE Filed April 8, 1942 5 Sheets-Sheet 2 CARI. G. FLYG'ARE HG.3 HERsERT,A.5/L.vE/v MLAW March 14, 1944. c FLYGARE EI-AL 2,344,242

EXTERNAL-INTERNAL CYLINDRICAL GRINDING MACHINE Filed April 8, 1942 5 Sheqts-Sheet 3 CARL G. FLYG'ARE HERBERT A. s/LVEN Patented Mar. 14, 1944 EXTERNAL-INTERNAL CYLINDBICAL GRINDING MACHINE Carl G. Flynn: and Herbert A. Silven, Worcester,

Mass., assignors to Norton Company, Worcester, Mam, a corporation of Mambo lettl Application April's, 1942, Serial No. 438,091

12 Claims.

The invention relates to grinding machines, and more particularly to a grinding machine for grinding both external and internal surfaces of a work piece.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated grinding machine for successively grinding external and internal cylindrical surfaces on a work piece. Another object of the invention is to provide a hydraulically operated external-internal grinding machine with an interlock to prevent movement of the workpiece to an internal grinding position except when the external grinding wheel is in its rearmost or inoperative position. 1

Another object of the invention is to provide an electrically controlled interlock to prevent initiating an infeeding movement of the grinding wheel unless the grinding wheel slide is in a forward or operative position. Another object of the invention is to provide a hydraulic interlock to prevent movement of the work table beyond its normal reciprocatory stroke when the grinding wheel is in a forward or operative position. other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. l is a front elevation of the improved external-internal cylindrical grinding machine;

Fig. 2 is a right-hand end elevation of the grinding machine, as shown in Fig. 1;

Fig. 3 is a fragmentary vertical sectional view, on an enlarged scale, taken approximately on the line 3--3 of Fig. 1, showing the transverse and longitudinal feeding or traversing mechanism for the internal grinding head;

Fig. 4 is an electric wiring and hydraulic piping' diagram illustrating the actuating and control mechanisms of the grinding machine;

Fig. 5 is a fragmentary longitudinal sectional view, on an enlarged scale, through the hub portion of a propeller blade, showing the surfaces to be ground;

line 8-3 of Fig. 1, showing the manually operable work table traversing mechanism;

Fig. 9 is a fragmentary front elevation, on an enlarged scale, of a portion of the control mech- Fig. 6 is a vertical sectional view, on an enanism on the front of the grinding machine;

Fig. 10 is a fragmentary horizontal sectional view, taken approximately on the line Ill-l0 of Fig. 9;

Fig. 11 is a fragmentary vertical sectional view,

taken approximately on the line of Fig. 9, through the work table reversing mechanism;

Fig. 12 is a fragmentary cross sectional view, taken approximately on the line |2-|2 of Fig. 11, through the load and fire mechanism; and

Fig. 13 is a horizontal sectional view, taken ap proximately on the line |3--|3 of Fig. 9, through the hydraulic interlock valve.

A' grinding machine has been illustrated in the drawings comprising a base 20 which supports a longitudinally reciprocable work supporting table 2| on the usual v way 22 and flat way 23 for a longitudinal reciprocatory movement relative to the base 20. The table 2| pivotally supports a swivel table 24 clamped thereto which serves as a support for a rotatable work supporting head 25 which rotatably supports a work piece 26 in operative position relative to a grinding wheel 21. The grinding wheel 21 is mounted on one end of a rotatable wheel spindle 28. The wheel spindle 28 is journalled in suitable bearings in a transversely movable wheel slide 29 which is arranged to slide transversely on a V-way 30 and flat way 3| on an intermediate slide 32. The grinding wheel 21 may be driven by means of an electric motor 33 mounted on the upper surface of the wheel slide 29 controlled by the push button switch 48. The motor 33 is provided with a multiple V-groove pulley 34 which is drivingly connected by multiple V-belts 35 with a multiple V-groove pulley 36 mounted on the right-hand end of the wheel spindle 28 (Fig. 1). The intermediate slide 32 is supported by the usual V-way 31 and flat way 38 formed on the slide support 39 mounted on the rearwardly extending portion of the base 20 to support the intermediate slide 32 for a transverse movement relative to the base 20.

Work support and drive The rotatable work support 25 preferably comprises a rotatable hollow spindle 40 which is journalled in bearings 4| and 42. The rotatable work support 25 illustrated is particularly adapt-- ed for supporting an irregularly shaped work piece 26 which, as illustrated, is an aeroplane propeller blade having exterior cylindrical surfaces 43 and 44 and an internal surface 45 to be ground. A chuck 46 is mounted on the righthand end of the spindle 40 and serves to center and clamp the hub end of a propeller blade in position for a grinding operation. A second chuck "is provided for supporting and center-.

ing the blade portion. The chuck 41 is longitudinally adjustable relative to the spindle Ill and is also angularly adjustable so that the clamping laws may be positioned to engage opposite edges of the propeller blade. VA

The work spindle 49 may be driven by an electric motor 99 controlled by the push button switch 49 which is flxedly mounted on an adjustable slide on a pivotally mounted motor support 9|. The motor support II is pivotally supported by a shaft I2 mounted on integral projections on the upper bearing caps of the bearings 4| and 42. An adjusting screw 53 is provided for locking the motor support I to tension the driving belts. The motor III is provided with a multiple V-groove driving pulley 54 which is connected by multiple V-belts 55 with a multiple V-groove pulley 59 mounted on the righthand end of a rotatable shaft 51 (Figs. 1 and 2). The shaft 51 is provided at its other end with a multiple V-groove pulley 99 which is connected by multiple V-belts 59 with a pulley 6!! which is mounted on the left-hand end of the work supporting spindle 40 (Fig. 1). It will thus be readily apparent that rotary power from the motor I! will be transmitted to rotate the work spindle 49 together with the work supporting chucks 49 and 41 to rotate the work piece 29 for a grinding operation. I

Work table control mechanism The table 2| is preferably reciprocated by a hydraulically operated mechanism comprising a cylinder 92 which is supported in flxed relation with the under side of the table 2|. A pair of spaced pistons 89 and 94 are slidably mounted within the cylinder 92 and are connected by hollow piston rods 99 and II, respectively. The hollow pistonrods II and 99 are connected to hollow brackets 91 and 99, respectively, which are mounted in flxed relation with the opposite ends of the base 29.

Fluid under pressure is supplied from a suitable source, such as a reservoir 19 formed in a box-like portion of the base 20. driven fluid pump II which is controlled by the push button switch 69 is provided for drawing fluid through a pipe 12- from the reservoir and forcing fluid under pressure through a pipe 13 to a venting type relief valve I4 to be hereinafter described. The venting type relief valve "is connected by a pipe with a check valve 19 which is in turn connected by a pipe 11 to force fluid under pressure to a table reversing or controlling valve I9. The table reversing valve 18 is a piston type valve comprising a valve stem I9 having formed'integrally' therewith valve pistons 99, 9|, 82, 93 and 94. In the position of the valve I8 (Fig. 4'), fluid under pressure passing through the pipe- I1 enters a passage or chamber 99 in the valve casing and passes into a valve chamber located between the valve pistons 92 and 93 and then out through a passage 99 and a pipe 91 which connects with a chamber 99 in the bracket 88 and passes through the hol low piston rod 66 into a cylinder chamber 89 to cause the cylinder 62 and table 2| to move toward the right (Fig. 4)} A pipe 99 connects the passage 89 with a combination speed control and stop and start valve 9|. This valve BI is a piston type valve comprising a valve stem 92 having formed integrally therewith valve Distons 99 and 94.

mums

A motor pally operable speed adjusting knob In the position of the valve 9! (Fig. 4), fluid may by-pass from one end of the cylinder 92 to the other. Fluid withinthe pipe 99 is connected with a' valve chamber 99 located between the valve pistons 93 and 94.- A pipe 90 connects the. valve chamber 99 with a passage U in the valve I8. The passage 91 is connected-by a pipe 94 with a chamber 99 formed in the bracket 91 through which fluid passes to the hollow piston rod BI, into a cylinder chamber I99. It will be readily apparent from the foregoing disclosure that in the position of the valves 19 and M (Fig. 4) fluid may readily pass between opposite ends of the table reciprocating cylinder 92.

The valve 9| serves also as a stop and start valve and is arranged to be actuated by a pivotally mounted control lever IIII which is supported by a stud I92 flxedly supported by a bracket I 03 which is fixed relative to the front or the machine base 29. The lever IN is connected to move the valve stem 92 to position the valve pistons 93 and 94, respectively. asdesired. When it is desired to start the reciprocatory movement of the work table 2|, the control lever "II is moved in a counterclockwise direction (Fig. 4) to move the valve stem 92 together with the valve pistons 99 and 94 toward the left so that the angularly formed end face I04 0! the valve piston 94 will uncover at least a portion of a V-port I 95 so that fluid exhausting from the valve 19 througha pipe I99 may pass through the V-port I09 into a valve chamber I91 and pass outwardly through a'pipe I09 which exhausts into the reservoir I0.

When the stop and start valve 9I is opened to allow fluid to pass through the V-port I05, with the table reversing valve I9 in the position illustrated in Fig. 4, the cylinder 92 and the table 2| will start their reciprocatory movement toward the right (Fig. 4). During the movement of the table 2I toward the right, fluid within the cylinder' chamber I99 will exhaust through the hollow pitson rod 6I,'through the chamber 99 in the bracket 91, and through the pipe 99. An arrow-pointed spring-pressed detent III! is provided to engage a serrated portion II I of the valve stem 92 normally to hold the valve stem 92 agains rotary motion. A man- Il 2 is mounted on the outer end of the valve stem 92 and serves to facilitate arotary adjustment to vary the position of the angular end face I94 of the valve piston 94 relative to the V-port I05 so that the exhaust of fluid passing through the V-po rt I09 may be regulated as desired to end of the rock shaft us. An arm m is rotatably supported on a hub portion I22 ofthe lever I29. -The arm I2I carries a stud I22 which I engages a notch I24 formed in the valve stem I9.

A load and flre mechanism is provided comprising a compression spring I29 (Fig. 12) which is contained within a pair of telescoping sleeves I29 and I21. The sleeves I28 and I2! are provided at their ends with transversely extending notches I29 and I29, respectively. The arm I29 carries a pair of studs I39 and lil which ride within the notches I28 and I28, respectively.

Similarly; the arm I2I supports a pair of studs.

I82 and I33 which also ride in the notches I28 and I29. respectively. It will be readily apparent from the foregoing disclosure that when One of the table dogs H1 or H8 engages and swings the reversing lever II5, the movement of the arm I25 with the reversing lever II will compress the spring I before transmitting a shifting move- Manual table traversing mechanism A manually operable table traverse mechanism is provided, comprising a manually operable hand wheel I40 which is fixedly supported on a sleeve I (Fig. 8). The sleeve I is slidably mounted on a stud I42 which is fixed relative to the base 20 of the machine. A gear I43 is formed integral with the sleeve Ill and meshes with a gear I44 which is keyed on the outer end of a shaft I45. A pinion I46 is formed integral with the inner end of the shaft I45. The pinion I46 meshes with a rack bar I41 which is fixedly mounted on and depends from the under side of the table 2I. The

sleeve I is slidably mounted on the stud I42 so that during power traverse or reciprocation of the table 2|, the gear in may be shifted toward the left (Fig. 8) out of mesh with the ear I44 so that the manually operable hand wheel I40 will remain stationary. A lever I48 is supported by a rock shaft I49 which in turn supports a short arm I50. The short arm I50 is arranged in the path of an adiustably mounted projecting portion I5I on the lever IOI. arranged so that when the lever IOI is moved in a counterclockwise direction'(Fig. 11) to initiate a power reciprocating movement of the table 2|, the hand wheel I40 together with the gear I43 will be moved toward the left (Fig. 8) to throw it out of mesh with the gear I44, thus rendering These parts are the manually operable traverse wheel I40 inoperative during the hydraulic traversing or reciprocating movement of the table 2 I.

that the work supporting swivel table 24 may be readily traversed to an internal grinding position to be hereinafter described. A grinding wheel positioning mechanism is provided, comprising a hydraulically operated mechanism interposed between the wheel slide 29 and the intermediate slide 32. This mechanism may comprise a hydraulic cylinder I which is formed integral with the intermediate slide 32. A piston I56 is slidably mounted within the cylinder I55. A piston rod I51 is connected at one end to the piston I56 and at the other end to a bracket I58 depending from and fixedly mounted to the under side of the wheel slide 29.

A manually operable control valve I60 is provided for controlling the admission to and exhaust of fluid from the cylinder I55. The valve I60 is a piston type valve comprising a valve stem I6I having valve pistons I62, I63, I84 and I formed integral therewith. A manually operable control lever I66 is provided for actuating the valve stem I61. The control lever I66 is pivotaily supported by a stud I51 which is in turn supported by a bracket I58 fixedly mounted on the front of the machine base. In the position of the valve I60 (Fig. 4), fluid under pressure passing through the pipe 11 passes through a pipe I69, into a valve chamber located be tween the valve pistons I63 and I54 and passes out through a pipe I10, into a cylinder chamber Hi, to move the piston I56 to its rearmost position so that the grinding wheel 21 is moved to its extreme rearward or inoperative position out of the path of movement of the work head 26. During the rearward movement Of the piston I56, fluid within a cylinder chamber I12 is exhausted through a pipe I13, through a valve chamber located between the valve pistons I54 and I65, and .passes out through an exhaust pipe I14, into the reservoir 10. A valve I15 is provided in the exhaust pipe line I14 so that the exhaust of fluid from the cylinder I55 ma be readily controlled, thereby controlling the speed of movement of the grinding wheel 21' to and from an operative position.

When it is desired to move the grinding wheel 21 forward to an operative position, the control lever I66 is moved in a counterclockwise direction (Fig. 4) to shift the valve stem I6I toward the right (Fi 4) so that fluid under pressure from the pipe I69 will pass through thevalve chamber located between the valve pistons I64 and I 66 and through the pipe I13, into the cylinder chamber I12 to cause the piston I56 and the wheel slide 29 to move forwardly into an operative position with the grinding Wheel 21 adjacent to the surface of the work piece to beground.

Wheel feeding mechanism A grinding wheel feeding mechanism is provided interposed between the intermediate slide 32 and thebase 20. The wheel feeding mechanism illustrated combines a manually operable wheel feed and a hydraulically operated power feeding mechanism. I'his feeding mechanism may comprise a rotatable cross feed screw I which is rotatably journalled in the base 20 in a suitable bearing I 8| at its forward end and in a slidably keyed sleeve I82 at its other end. A depending half nut I63 is fixedly mounted on and depends from the under side of the intermediate slide 32 and meshes with or engages the feed screw I 80.

In order to facilitate rotar adjustment or the feed screw I 80, a sleeve I84 is slidablykeyed to the forwardly extending portion of the feed screw I80 and is rotatably supported by the bearing I8I. A gear I65 is keyed on the sleeve I84 and meshes with a pinion I86 formed on a rotatable shaft I81. The shaft I81 is journalled in bearings I88 and I89 which are supported in fixed relationship with the base 20. A gear I90 is mounted on the forward end of the shaft I 81 and meshes with a gear I 9i. The gear I 9| is rotatably supported on a stud I92 which is in turn fixedly mounted in a bracket I93. The bracket I93 is fixedly mounted on the front of the machine base 20. A manually operable feed wheel I94 is also rotatably mounted on the stud I9I and is connected so as to rotate the gear I9I. The feed wheel I94 is substantially the same as that shown in the expired U. S. patent to C. H. Norton, No. 762,838 dated June 14, 1904, to which reference may be had for details of disclosure not contained herein. It will be readily apparent from the foregoing disclosure that a rotary motion of the feed wheel I will be transmitted through the mechanism above described to rotate the feed screw I20 to impart atransverse feeding moi ement .to the intermediate slide 22, the wheel slide 28. and the grinding wheel 21. The direction of movement of the slides and the grinding wheel 21 is'determined by the direction of rotation of the feed wheel I.

within the cylinder I". A double end piston rod I21 is connected to the piston I and atits lefthand end (Fig. 4) to the slidably mounted sleeve I 82. It will b readily apparent from the foregoing disclosure that when fluid under pressure is admitted to a cylinder chamber I92 to cause the piston I92 to move toward the left (Fig. 4), it will impart a forward feeding movement through the feed screw I O to the intermediate slide 22 so as to impart a corresponding feeding movement to the wheel slide 22 and the grinding wheel 21. Similarly, if fluid under pressure is admitted to a cylinder chamber I98 to cause the piston I" to move toward the right into the position illustrated in Fig. .4, a rearward movement of the grinding wheel 21 will be obtained.

A reversing or feed control valve 200 (Fig. 4) is provided for controlling the admission to and exhaust of fluid from the feed cylinder Isl. The valve 200 is a piston type valve cdmprising a valve stem "I having formed integrally therewith

valve pistons

202, 202, 204 and 205. A compression spring 206 serves normally to hold the valve stem 2 in its right-hand end position (Fig. 4). An electric solenoid 201 is operatively connected to the valve stem 20I so that when energized the solenoid 201 will move the valve stem 2I|| toward the left (Fig. 4) to reverse the flow of fluid to the feed cylinder I95.

Fluid under pressure from the puinp 1| passing through the pipe 11 passes through a pipe 202. into -a valve chamber located between the

valve pistons

202 and 202, and passes through a passage 208 into the cylinder chamber I99 to move the piston I96 rearwardly, that is, toward the right (Fig. 4) into the position illustrated.

Duringthis movement, fluid within the cylinder chamber I98 .exhausts through a passage 2| Ii,

into a valve chamber located between the valve Dash .pot feed mechanism A suitable fluid pressure control or feed regulating mechanism is provided for modifying the rapid approaching movement caused by the piston ISO- to obtain a controlled and predetermined grinding feed of the grinding wheel 21. A selfoontained dash pot feed regulator is provided, comprising a pair of dash pot cylinders 2|5 and 2|! which contain dash pot pistons 2" and 2Il,

respectively. The dash pot pistons 2| 1 and 2|! and their respective cylinders are arranged with their axes parallel to each other and spaced on diametrically opposite sides of the axis of the piston rod I21. The dash pot pistons 2" and 2" are normally held in a rearward (right-hand) position by means of the compression springs. An adjustable stop screw 2|! serves to limit the rearward movement of the dash pot pistons 2H and 2 I8, respectively. A slidable sleeve 22. is supported on the rear extension of the piston rod Ill. The sleeve 220 has a flanged portion 22I which is either formed integral therewith or flxedly se-. cured thereto. The flange 22I is arranged to engage the right-hand end faces of the dash pot pistons 2I1 and 2", respectively. The stop screw 2|! engages the flange 22I and thereby serves to' limit the rearward movement of the dash pot pistons 2" and 2" toward the right (Fig. 4).

The rapid forward feeding movement of the grinding wheel 21, wheel slide 29 and intermediate slide 22 continues until an adjustable nut 222 on a threaded portion 222 of the rearward extension of the piston rod I21 engages the right-hand end of the sleeve 220. Continued movement of the piston rod I91 moves the sleeve 220 and the flange 22I toward the left and continued movement serves to move the dash pot pistons 2 I1 and 2 I8 in a direction toward the left (Fig. 4). When the flange 22I engages the ends of the dash pot pistons 2" and 2Il, respectively, the rapid appreaching or feeding movement of the grinding wheel 21 toward the work piece 28 as produced by the piston I98 is reduced to a slower predetermined grinding feed due to the fact that fluid confined within the dash pot cylinders 2|5 and 2I6, respectively, which are interconnected, exhausts through a passage 224, a needle valve 225, through a pipe 226,. into a reservoir 221. By adjusting the aperture of the needle valve 225, a desired and predetermined infeeding movement of the grinding wheel 21 may be obtained.

When fluid under pressure is admitted to the cylinder chamber I to cause a rearward movement of the piston. I92, the sleeve 22li together with the flange 22I is moved rearwardly by means of the released compression of the spring within the dash pot cylinders 2|! and 2I6 which returns the dash pot pistons 211 and 2I8, respectively, to their rearward position and moves the flange 22I into engagement with the stop screw 2|9. During the rearward movement of the dash pot pistons 2I1and 2I8, a suction is created within the dash pot cylinders 2I5 and 2|6, respectively, which serves to draw fluid from the reservoir 221, through a pipe 220, and a ball check valve 23|,-to flll the dash pot cylinders 2I5 and 2I5 for the next infeeding movement of the grinding wheel 21. During the infeeding movement of the dash pot pistons 2|1 and 2 I8, fluid within the dash pot cylinders 2 I5 and 2|6 serves to hold the ball check valve 23| closed so that fluid'within the dash pot cylinders 2I5 and H6 is forced out through the passage 224 and the needle valve 225 and a throttlevalve 222 until the passage 224 is closed, into the reservoir 221 to control the rate of the infeeding movement, as desired. The adjustable throttle valve 232 is connected between the pipe 220 and a chamber 222 to facilitate exhaust of fluid from the dash pot cylinders 2|! and 2| after the passage 222 is closed by the dash pot piston 2". If desired, the throttle valve 222 may be used to give a very fine flnal feeding movement of the grinding wheel 21 just prior to a positive stop 234 engaging a stop surface 235 which positively limits the forward advance of thegrinding wheel 21. toward the work axis. In the latter case, two distinct speeds of the grinding wheel 21may be obtained, one feed by manipulation of the valve 232 combined with the opening of the needle valve 225 which would continue until the passage 224 is cut off, after which the positioning movement is reduced to a very slow lnfeed controlled by the throttle valve 232.

In order to maintain the desired quantity of fluid in the reservoir 221, initially to fill the chamber and thereafter to replenish leakage from the feed regulator system, a pipe 236 is connected between the pipe 208 and the pipe 226. A valve 231 is provided in the pipe line 236 which may be readily opened to allow the desired amount of fluid from the fluid pump 1! to pass into the reservoir 221, after which the valve 231 may again be closed.

Internal grinding In order to grind the internal surfaces 45 (Fig. 5), an internal grinding head 240 is mounted at the right-hand end of the machine base 20 (Fig. 1). After the external surfaces 43 and 44 of the propeller blade 26 have been ground and the grinding wheel 21 moved to a rearward or inoperative position, the work table 2! may be traversed longitudinally toward the right (Fig. 1) to position the work piece 26 in broken line position 260. (Fig. 1) in close proximity to an internal grinding wheel 24! supported by the internal grinding head 240. A stop dog 242 is carried adjustably supportedby the T-slot H9 and is arranged to locate the work piece 26 in position 26a for an internal grinding operation. A

bracket 243 is fixedly supported on the front of the base 20. The bracket 243 carries an adjustable stop screw 244 which is arranged in the path of the stop dog 242 precisely to locate the sliding table 2| when it is moved to an extreme righthand end postion for an internal grinding operation.

A pair of

brackets

245 and 246 are fixedly mounted at the right-hand end of the machine base 20 on the front and back surfaces thereof and serve as a support for an inverted U-shaped frame 241 which supports the internal grinding fixture. The frame 241 is adjustable longitudinally relative to the

brackets

245 and 246, respectively. The upper surface of the

brackets

245 and 246 are provided with longitudinally extending T-

slots

248 and 249, respectively, which are arranged parallel to the

slideways

22 and 23 of the machine base 20. in position by bolts 25!) and 25!, respectively. It will be noted that the inverted U-shaped frame 241 bridges over the right-hand end of the tables 2| and 24 so that when the table 24 moves to an extreme right-hand end position, it passes within the aperture formed between the U-shaped frame 241 and the base 26.

A swivel plate 252 is supported and clamped on the frame 24'! and is arranged so that it may be swivelled about a stud 253 to facilitate angularly adjusting the path of travel of the internal grinding Wheel 24! so thatits axis will move parallel to the axis of rotation of the work piece 26 for grinding a true internal cylindrical surface or at an angle thereto if it is desired to produce a tapered internal surface. A longitudinally traversable carriage 254 is supported on a flat way 255 and a V-way 256 formed onthe upper surface of the swivel platen 252. By adjusting th position of the platen 252, as previously described, the flat.

way 255 and V-way 256 may readily be positioned either parallel to or at an angle to the V-way 22 and flat way 23 which supportthe work table 2|.

A manually operable traversing mechanism is provided for traversing the carriage 254 longitudinally comprising a manuallybperable hand wheel 251 which is keyed to a rotatable shaft 258 I which is journalled in a. casing 258 mounted on the swivel plate 252. A gear 268 is mounted on the inner end of the shaft 258 The gear 268 meshes with a gear 26! which is rotatably supported on a stud 262 carried-by the casing 258. The gear 26! meshes with a gear 263 mounted on the outer end of a rotatable shaft 264 which is journalled in sleeve hearings in the swivel plate 252. A gear 265 is mounted on the inner end of the shaft 264 and meshes with a rack bar 266 de- The frame 241 is adjustably clamped v pending from the under side of the longitudinally movable carriage 254. I

Adjustable dogs 261 and 268 are supported by a T-slot 269 formed in the front edge of the carriage 254. The dogs 261 and 268 are arranged in the path of a stop abutment 210 fixedly supported on the plate 252, so that the longitudinal traversing movement of the carriage 254 may be lim ited as desired. A plate 21! is angularly and adjustably supported on the longitudinally movable carriage 254. A dovetailed slideway 212 is formed on the upper surface of the plate 21! which mates with a correspondingly shaped slideway formed in a transversely movable wheel slide 213.

A nut and screw feeding mechanism is provided for ieedingthe wheel slide 213 transversely as desired. A rotatable feed screw 214 is journalled in bearings 215 and 216 carried by the frame 21!. A nut 211 meshes with the feed screw 214.. A manually operable hand wheel 218 is mounted on the outer end of the feed screw 214. It will be readily apparent from the foregoing disclosure that rotation of the hand wheel 218 Will be transmitted through the feed screw 214 and the nut 211 to move the wheel slide 213 transversely.

The internal grinding wheel 24! is supported adjacent to the end of a wheel spindle 280 which is rotatably-supported in a housing 28! containing bearings for the spindle. This spindle housing 28! is a cartridge type cylindrically shaped member which fits within an aperture formed in a split bracket 282. The internal grinding wheel cartridge unit 28! may be readily clamped in adjusted position in the bracket 282. The bracket 282 is provided with a dovetailed shaped base 283 extending longitudinally which mates with a correspondingly shaped dovetail upon the upper surface of the wheel slide 213 so that the bracket 282 may be adjusted longitudinally relative to the wheel slide 213. The internal grinding wheel 24! and its supporting spindle 288 may be driven by means of a motor driven mechanism comprising an electric motor 284 which is supported on a transversely adjustable supporting dovetailed slide 285. The motor 284 is provided with a driving pulley 281 which is connected by a driv ing belt 288 with a pulley 289 which is mounted on a jackshaft mounted in a bracket 290 supported on the wheel slide 213. A belt 29! having idlers for proper tension connects the pulley 288 with a pulley 292 mounted on the end of the wheel spindle 280 to rotate it together with the grinding wheel 24! during an internal' grinding base ll.

Hydraulic interlock In order to prevent a traversing movemeht of the work table 2| to,an internal grinding position before the gridingwheel 21 is moved to a rearward position out of the path of movement of the work head 25, it is desirable to provide a suitable interlocking mechanism for preventing movement of the table 2| unless the wheel slide 29 and the intermediate slide I2 are in a rearward or inoperative position. This is preferably accomplished by means of the venting type relief valve 14. Fluid under pressure from the fluid pump passes through the pipe II into a chamber 295 in the venting type relief valve ll. The relief valve I4 is of a balanced pressure type, comprising a valve member 286 and a seat 291 therefor. A piston 2881s formed integral with the valve member lll. A bleeder hole 2 passes through the piston-2ll and serves to allow fluid under pressure to' pass therethrough into a valve chamber Ill. The valve chamber Ill is connected by means of a e Ill with a ball check valve I02 which is normally held in a seated or closed position by means of a spring llll. An adjusting screw I is provided for adjusting the compression of the spring Ill as desired.

The venting valve chamber 295 is connected by the short pipe with the'check valve ll which supplies fluid under pressure through the pipe 11 to the various mechanisms of the machine, as above explained. The relief valve 14 is operatively connected so that if an attempt is made to move the table 2| to an internal grinding position before the wheel slide 28 is moved rearwardly to an inoperative position, the venting type relief valve piston 298 is opened todrop the operating pressure within the hydraulic system to substantially zero so as 'to' prevent movement of the table 2|. A venting control is provided for relieving the pressure within the valve chamber Ill. The passage Ill (Fig. 6) is connected with a passage Ill. The passage 306 is in turn connected by a pipe III with a .valve 308. The valve lll is a rotary type valve having a valve rotor Ill. The valve rotor Ill contains a passage Ill which connects the pipe Ill'l with a pipe ll I, when the valve rotor is rotated in a clockwise direction so .that fluid within the venting pipe I01 may pass through the valve Ill and out through pipe III which leads to the reservoir in a manner to be hereinafter described. The valve lll is preferably interconnected with the reversing lever lll so that when it is desired to allow the table 2| to traverse to its extreme right-hand end position into broken line position 2|a (Fig. l), the valve Ill may be actuated automatically to vent fluid within the pipe I01, thus opening the venting type relief valve 14 unless the wheel slide 2! together with the intermediate slide l2 are in their extreme rearward position.

A slidably mountd handle I|2 is mounted on the upper portion of the reversing lever Ill. The slidably mounted portion I|2 carries a stud lll which is positioned in the path of the table reversing dogs I I and Ill. When it is desired to allow the table 2| to travel to the internal grinding position 2|a, the knoblll is raised to lift the pin lll out of the path of the table dog ll'l so as to allow the table 2| to traverse to its extreme right-hand end position. A lever lll ispivotally mounted by means of a stud us flxed on a bracket lll (Figs. 9 and 10). The lever Ill is provided with an arcuate-shaped elongated slot Ill within which the stud III is free to move as the reversing lever Ill is actuated by the passes through the elongated slot III. The bell crank lever lll is also provided with a downwardly extending arm having a cylindrically shaped end portion I22.

It will be readily apparent from the foregoing disclosure that if the knob Ill is raised to attempt to move the table 2| to an internal grinding position when the wheel slide 2l and/or the intermediate slide l2 are in a forward or grinding position, the raising of the knob l|2 will lift the stud lll (Figs. 9, 10 and 11) to shift the valve rotor Ill (Fig. 4) so as to vent the relief valve H, thus raising the valve member Ill of the relief valve ll so as to allow substantially the entire capacity of the fluid pump H to pass directly through the pipe l2l into the reservoir ll, thus stopping the table 2| and preventing its movement to an internal grinding position.

A forked arm or actuating lever I24 is mounted on the outer end of a valve stem I25 of the valve rotor I08. It will be readily apparent from the foregoing disclosure that when the knob I|2 of a bell crank lever III in a counterclockwise direction to impart a clockwise rotary motion to the valve rotor Ill so that the passage lll in the valve rotor llll will connect the venting pipe ll with the exhaust pipe Ill.

When the wheel slide 2l is moved to a rearward or inoperative position relative to the intermediate slide I2, -a cam plate I2l adjustably mounted on a plate I29 flxed to the-side of the wheel slide 28 (Fig. 4) closes a valve lll so that when the knob l|2 is raised to allow the stud III to pass by the table dog I", thus actuating the valve rotor lll of the valve Ill, the valve Ill being closed will prevent venting of fluid through the pipe ll'l so that the table 2| will continue its movement toward the right until the dog 242 engages the stop screw 2 to position the table 2| and the work piece 26 in broken line positions 2 la and 26a (Fig. 1). This construction above described provides a fluid interlock which prevents traversing of the table 2| beyond its normal stroke except when the grinding wheel 21 is in a rearward or inoperative position. v

The valve Ill is mounted on the right-hand end face of the rear portion of the base 2l. The valve lIl is a piston type valve, comprising a valve stem Ill having formed integrally therewith a pair of valve pistons ll2 and III. A compression spring Ill within the valve Ill normally tends to hold the valve stem lll in an uppermost position, so that fluid within the pipe III will pass through a valve chamber Ill and through an exhaust pipe Ill into the reservoir II.

The cam plate I28 is adjustably supported on the plate I28 which is mounted on the wheel slide 2l andisarrangedinthepathofaroller Ill mounted on the upper end of the valve stem 33|.-' When the wheel sndeza and/or intermediate slide32 are in their forward or grinding positions, the valve stem 33I will be in a raised pacity of the fluid directly from the pump II,

through the pipe 323, into the reservoir 10.

Electrical control An electrical. control circuit is provided for starting and stopping the grinding cycle, comprising a control lever 345 which is pivotally supported on a bracket in flxed relationship with the front of the base 20. .The control lever 35 is arranged when moved in a counterclockwise direction to actuate a push button starter switch 345 or when rocked in a clockwise direction to actuate a push button stop switch 341 whereby the grinding cycle may be interrupted when 'desired. The push button switches 345 and 341 are connected through a magnetic starter or relay switch 348 to control the energizing and deenergizing of the solenoid 201 so as to actuate the feed control valve 200- as desired. A normally closed limit switch 349 is mounted on the right-hand end face of the rear portion of the intermediate slide 32 adjacent to the valve 330 and is arranged to be actuated by the cam plate 329 when the wheel slide .29 is moved to a rearwa d or inoperative position.

After a cylindrical grinding operation has been completed and the wheel slide 29 and intermediate slide 32 are moved to rearward or inoperative positions, the cam plate 328 engages and depresses the roller 331 into "the position illustrated in Fig. 4 to close the valve 330 so that the valve piston 332 will cut off the pipe 3H from the pipe 335, thus preventing venting of fluid passing from the pipe 301 into the reservoir 10 if and when the wheel slide 29 is in its rearmost position so as to open the circuit of the limit switch 249 and prevent energization of the solenoid 201 unless the wheel slide 29 is'moved forward for a. grinding operation. The control lever may then be rocked to initiate a forward feeding movement of the grinding wheel 21 as the limit switch 349 has been closed.

The limit switch 349 is also arranged to deenergize the solenoid 201 when the wheel slide 29 has been moved to a rearward or inoperative position by actuation of the control lever I 55 in case the operator does not wish to actuate the control lever 345 to momentarily open the push button stop switch 341 and break the circuit to the relay switch 348 and thus deenergize the solenoid 201 to move the intermediate slide 32,; to its rearward position. When the wheel slide 29 is movedforward, the cam plate 328 moves toward the left (Fig. 4) so as to allow the limit switch 349 to close after the wheel slide is in its forward position, in which position the control lever 345 may be shifted in a counterclockwise direction to initiate a grinding infeed of the intermediate slide 32 and the grinding wheel 21.

The operation of this external-internal cylindrical grinding machine will be readily apparent from the foregoing disclosure. Assuming all of the part to haVe been previously adjusted for a given grinding operation, a work piece such as a propeller blade 25 is positioned within the hollow work spindle 40 and is held in an adjusted centered position with its axis aligned with the axis of the work spindle by means of the'work chucks and 41 so that the external surfaces 43 and 44 and the internal surfaces 45 may be ground precisely to the desired and predetermined extent. After the work piece 25 has been positioned in the work head 25, the push button switches 48, 49 and 59 are actuated to start the grinding wheel driving motor 33, the headstock motor 50, and the motor for driving the fluid pump 1|, respectively. The work table 2| may then be moved longitudinally either by the hydraulically operated mechanism above described or by manual rotation of the hand traverse wheel I40.

When the work has been positioned so that the portion 43 or 44 to be ground is opposite the grinding wheel, the lever IE5 is moved in a counterclockwise direction (Fig. 4) to admit fluid under pressure into the cylinder chamber I12 to move the piston I together with the wheel slide 29 to a. forward or operative position. The lever 345 may then be rocked in a clockwise direction to actuate the push button switch 345 so as to energize the solenoid 201, thereby shifting the feed control valve 200 toward the right (Fig. 4) to admit fluid under pressure through the passage 2I0 into the cylinder chamber I98 to cause a forward infeeding movement of the grindingwheel 21 to grind the work portion 44 to the desired and predetermined extent. After the work portion 44 has been ground to the,desiredwsuz d predetermined extent, the control lever 345- may be moved in a clockwise direction (Fig. 4) to deenergize the solenoid 201 and thereby cause the intermediate slide 32 to move to its rearward position, after which the table 2| may be traversed either hydraulically or manually to position the work surface 43 opposite the grinding wheel 21. The grinding wheel 21 may then be fed toward the work by actuation of the control lever 345 to grind the work portion 43 to the desired extent.

After the external surfaces have been ground to predetermined sizes, the control leverf345 may be shifted in a counterclockwise direction to deenergize the solenoid 201, thus releasing the compression of the spring 205 to return the valve 200 into the position illustrated in Fig. 4 so as to cause a rearward movement of the piston 95, thus moving the intermediate slide 32 rearwardly relative to the base 20. At the sametime the control-lever I55 may be moved in a clockwise direction to shift the valve I50 so as to admit fluid under pressure into the cylinder chamber "I (Fig. 4) to cause the wheel slide 29 and the grinding wheel 21 to move rearwardly to an inoperative position so that the work table 2| may be traversed longitudinally to an external grinding position.

The ,knob 3I2 on the upper end of the reversing lever I I5 may then be raised and the reversing lever I|5 shifted in a clockwise direction to cause the table 2| to move toward the right (Fig. 1) so that the pin 3|3 on the reversing lever will be raised out of the path of the reversing dog II1. Thetable 2| together with the work head 25 will continue its movement toward the right until the table dog 242 engages'the stop screw 244 to locate the work piece 25 in position its (as shown in broken lines in Fig. l) If desired, the table may be slowed down as the dog 2 approaches the stop screw 2 by actuation of the stop and start lever llll to partially close the V-port l", thus slowing down the table as it approaches a stopped position.

When the work piece has been positioned inposition 200, the internal grinding wheel motor I 204 may be started by actuation of the push buttonswitch 286. The internal grinding wheel 2 may then be traversed longitudinally by i actuation of the spoked hand traverse wheel I" to traverse the wheel Ill longitudinally. The

internal grinding wheel I may be fed transversely in either direction by rotation of the manually operable feed wheel I'll. By manipulation of the spoked traverse wheel I" and the a controlled exhaust of fluid from the table cylinder 6! so'that the'table 2| moves longitudinally toward the left into the full line position as indicated in Fig. 1. Due to a cam surface on the dog 1, the reversing pin or stud Ill is raised to pass over the dog 1, after which it drops under the influence of gravity into the position illustrated in Fig. 1 so that the reversing dogs Ill and Ill will be in operative position to actuate the reversing lever Hi.

In the operation above described, the external surfaces 43 and N are ground by these-called plunge-cut method. If desired, the table may be reciprocated by the hydraulically operated table reciprocating mechanism above described, in which case the table dogs ill and Ill control the extent oi the reciprocatory movement.

The wheel may be fed manually into the work to grind the same to the desired extent by a manual actuation of the feed wheel I.

A fluid pressure interlock which has been des scribed above serves to prevent a longitudinal movement of the table into an internal grinding position unless the wheel slide 28 is in its rearmost position. An electrical interlock is also provided which has been described above, to prevent initiating an infeeding movement of the grinding wheel, that is, an infeeding movement of'the intermediate slide 32, unless, the wheel slide has been moved forwardly on the intermediate slide 32 to an inoperative position.

After a work piece .26 has been ground externally and internally, .the wheel 21 together with the wheel slide "and intermediate slide 32 are moved their rearward or inoperative positions, the ucks 4i and 41 are actuated to release the work piece 26 which may then be readily withdrawn from the machine and replaced with a new work piece to be ground.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are all matter hereinbeiore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim:

i. In agrinding machine .having a base, a transversely movable rotatable grinding wheel, a longitudinally reciprocable table thereon, a rotatable work support on said table, means including table dogs to reciprocate said table through a predetermined stroke for an external cylindrical grinding operation, means to traverse said table beyond the normal reciprocatory stroke precisely to position said table for a second grinding operation, and a hydraulic interlock to prevent movement of said table to the second grinding position except when the grinding wheel is in a rearward or inoperative position.

2. In a grinding machine having a base, a transversely movable rotatable external grinding wheel, a longitudinally and transversely movable rotatable internal grinding wheel, a longitudinally reciprocable table on said base, a rotatable work support on said table, means including table dogs and a reversing lever to reciprocate said table through a predetermined stroke for an external cylindrical grinding operation, means to traverse said table beyond the normal reciprocatory stroke precisely to position said table for an internal grinding operation, and an interlock to prevent movement of said table to an internal grinding position except when the external grinding wheel is in a rearward or inoperative position.

3. In a grinding machine having a base, a transversely movable rotatable external grinding wheel, a longitudinally and transversely movable rotatable internal grinding wheel, a longitudinally reciprocable table on said base, a rotatable work support on said table, a fluid pressure system including a piston and cylinder to move said table longitudinally in either direction, means including table dogs and a reversing lever to control the direction of flow of fluid to said cylinder, means to facilitate traversing said table beyond the normal reciprocatory stroke precisely to position said table for an internal grinding operation, and a hydraulic interlock mechanism to prevent movement of said table to an internal grinding position except when the external grinding wheel is in a rearward or inoperative position. 4. In a grinding machine having a base, a transversely movable rotatable external grinding wheel, means including a piston and cylinder to move said wheel transversely, a manually operable control valve thereon to control the direction' of movement of said grinding wheel, a longltudinally and transversely movable rotatable internal grinding wheel, a longitudinally reciprocable table on said base, a rotatable work support on said table, a piston and cylinder operatively connected to move said table in either direction relative to said base, a manually operable traversing mechanism for said table to po sition said table for an external cylindrical grinding operation, means to facilitate traversing said table beyond the normal reciprocatory stroke precisely to position the table for an internsl grinding operation, and a hydraulic intersuccessfully achieved' As many possible embodilcck mechanism to prevent movement of said 'table to an internal grinding position except when the external grinding wheel is in a rearward or inoperative position.

5. In a grinding machine having a base, a

move said wheel transversely, a manually oper determined stroke for an externalcylindricalgrinding operation, means to facilitate traversing said table beyond the normal reciprocatory stroke precisely to position the table for an internal grinding operation, and a hydraulic interlock mechanism to prevent movement of said table to an internal grinding position except when the external grinding wheel is in a rearward or inoperative position.

8. In a grinding machine having a base, a transversely movable rotatable external grinding wheel, means including a piston and cylinder to move said wheel transversely, a manually operable control valve thereon to control the direction of movement of said grinding wheel, a longitudinally and transversely movable rotatable internal grinding wheel, a longitudinally reciprocable table on said base, a rotatable work support on said table, a piston and cylinder operatively connected to move said table in either direction relative to said base. means including a manually operable start and stop valve to control the traversing movement of said table, a reversing mechaism including a reversing lever and a reversing valve to change the direction of movement of said table, said start and stop valve and said reversing valve serving to facilitate positioning of the table for an external cylindrical grinding operation, means to facilitate traversing said table beyond the normal reciprocatory stroke precisely to position the table for an internal grinding operation, and a hydraulic interlock mechanism to prevent movement of said table to an internal grinding position except when the external grinding wheel is in a rearward or inoperative position.

7. In a grinding machine as claimed in claim 3, the combination with the parts and features therein specified, of a slidably mounted stud on reversing lever normally positioned in the path of said table dogs, manually operable means to move said stud out of the path of said dogs to facilitate a traversing movement of the table beyond the normal reciprocatory stroke precisely to position the table for an internal grinding operation, a venting type relief valve in said fluid pressure system normally to control the fluid pressure therein, a vent control valve associated therewith, and operative connections between said stud and said vent control valve which are arranged to open said vent control valve to vent said relief valve and thereby prevent a table traversing movement beyond the normal reciprocatory stroke unless the wheel slide is in a rearward orinoperative position.

the fluid pressure system between the vent control valve and the reservoir, an adiustably mounted cam on said wheel slide toactuate and close said normally open valve when the wheel slide is moved to an inoperative position, and operative connections between said stud and said vent control valve which are arranged to open said 7 vent control valve to vent said relief valve unless 8. In a grinding machine asiclaimed in claim 3, the combination with the parts and features therein specified, of a slidably mounted reversin stud on the reversing lever normally arranged in the path of said table dogs, a venting type relief valve normally to control the operating pressure within the fluid pressure system, a vent control valve associated therewith, a normally open valve the wheel slide is in its rearmost position.

9. In a grinding machine having a base, a longitudinally reclprocable table thereon, a rotat able work support on said table, a rotatable grinding wheel, a transversely movable slide therefor, a transversely movable intermediate slide interposed between the wheel slide and base, a hydraulic piston and cylinder interposed between the wheel slide and the intermediate slide to move said wheel slide relative tosaid intermediate slide through a relatively long positioning stroke to move the grinding wheel to or from an operative position, and means including a piston and cylinder interposed between the intermediate slide and the base to move said intermediate slide through a. relatively short controlled stroke to impart a feeding movement to the grinding wheel.

10, In a grinding machine having a base, a longitudinally reciprocable table thereon, a rotatable work support on said table, a rotatable grinding wheel, a transversely movable wheel slide therefor, a transversely movable intermediate slide interposed between the wheel slide and base,

a hydraulic piston and cylinder to move said wheel slide relative to said intermediate slide through a relatively long stroke to move the grinding wheel to and from an operative position', means including a piston and cylinder to move said intermediate slide relative to the base through a relatively short controlled stroke to impart a feeding movement to the grindingwheel, a control valve'to control the admission to and exhaust of fluid from said latter cylinder, a solenoid to actuate said valve to initiate an infeeding movement of the intermediate slide, and means including a limit switch which is arranged to prevent energization of said solenoid so as to prevent an infeeding movement of the intermediate slide unless the grinding wheel slide is in a forward or operative position.

11. In a grinding machine having a base, a longitudinally reciprocable table thereon, a rotatable work support on said table, a rotatable grinding wheel, a transversely movable wheel slide therefor, a transversely movable intermediate slide interposed between the wheel slide and base, a hydraulic piston and cylinder to move said wheel slide relative to the intermediate slide through a relatively long stroke to move the grinding wheel to and from an operative position, means including a piston and cylinder to move said I intermediate slide relative to the base through a relatively short controlled stroke to impart a grinding feed to the grinding wheel, a control valve to control the admission to and exhaust of fluid from said latter cylinder, a solenoid to actuate said valve to initiate an infeeding movement of the intermediate slide, a normally closed limit switch on said intermediate slide which is connected in series with said solenoid, an adjustably mounted cam on said wheel slide which is arranged to actuate and open said limit switch when the wheel slide is moved to a rearward or inoperative position relative to the intermediate slide to prevent initiating an infeedon the intermediate slide which is connected in ing movement of the intermediate slide unless tion.

10 thewheel slide is in a iorward or operative posil2. In a grinding machine having a base. a longitudinally reciprocable table thereon, a rotatable worksupport on said table, a rotatable grinding wheel, a transversely movable slide therefor. a transversely movable intermediate slide interposed between the wheel slide and base, a hydraulic piston and cylinder to move the wheel slide relative to the intermediate slide through ar'elativelylongstroketomove thegrinding wheel to and from an operative position, means including a piston and cylinder to move said inassess:

termediate slide relative tosaid base through a relatively short controlled stroke to impart a feeding movement to thesrinding wheel. a control valve for said latter cylinder, a solenoid to shiitsaldvalvetocauseaninieedinsmovement oi the intermediate slide and the grinding wheel, a manually operable switch to control saidsolenoid. and means including a normally closed limit switch which is arranged to prevent an infeeding movement oi the intermediate slide unless the wheel slide is in a forward or operative position.

CARL G. PLYGARE. HERBERT A. BILVEN.