US2264257A - Grinding machine - Google Patents

Description

Nov. 25, 1941. ARslDE 2,264,257

GRINDING MACHINE Filed Dec. 7, 1939 8 Sheets-Sheet l UHNZEHRS/D'E a n M NOV. 25, 1941. J GAR I E v. 2,264,257

GRINDING MACHINE Filed Dec. 7, 1939- I s Sheets-Sheet 2 *2; R a g (50% R k9 m awe/whom JaH/v ZEHHS/UE MMLAW Nov. 25, 1941. A lDE 2,264,257

- GRINDING MACHINE 8 Sheets-Sheet 5 Filed Dec. 7, 1939 NOV. 1 J. IUGARSIDE 2,

GRINDING MACHINE Filed Dec. 7, 1939 8 SheetsSheet 5 Jc/HN 1. E HRS /05 Ft Nov. 25, 1941. J. LGARSIDE GRINDING MACHINE I Filed Dec. 7; 1939 1 2' 8 Sheets-Sheet 6 226 Ja/wv ZGHRE/DE mm mm Nov. 25, 1941.

J. I. GARSIDE 'GRINDING MACHINE} Filed Dec. 7, 1939 8 Sheets-Sheet 8 Fry 16'. N B W JOHN Z HHS/DE Patented Nov. 25, 1941 UNETED tries onmnmc MACHINE Application December '7, 1939, SerialNo. 308,035

12 Claims.

The invention relates to grinding machines, and more particularly to a grinding machine for accurately grinding a helical groove on a work piece.

One object of the invention isto provide a simple and thoroughly practical grinding machine for grinding a helical groove on a work piece. Another object of the invention is to provide a grinding machine for grinding a helical groove which is automatic in operation from the time the operator has placed a workpiece in position until the grinding operation is finished. Another object of the invention is to provide a universal mounting for the grinding wheel whereby the grinding wheel and its supporting spindle may be swivelled about a horizontal and also about a vertical axis to position the grinding wheel for producing the desired helical groove on a work piece.

Another object of the invention is to provide a work driving and table traversing mechanism which are synchronously driven so that the rotation and traverse of the work piece arev coordinated. A further object of the invention is to provide a two-speed work drive mechanism whereby the work may be rotated and the table traversed at proper speeds for a grinding operation when the table is traversed in one direction and the table may be traversed at a rapid, rate during the return traverse while the wheel is out of operative engagement with the Work piece. 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. 1

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

Fig. l is a front elevation, having parts broken away and shown in section, of the improved helix grinding machine;

Fig. 2 is a right-hand end elevation of the machine, on an enlarged scale, having parts broken away and shown in section;

Fig. 3 is a fluid pressure and electric wiring diagram of the operating mechanisms of the machine;

Fig. 4 is a longitudinal sectional view, on an enlarged scale, through a portion of the wheel slide;

Fig. 5 is a fragmentary front elevation, on an enlarged scale, of the wheel feeding mechanism;

Fig. 6 is a fragmentaryvertical sectional view, on a slightly reduced scale, taken approximately on the line 6--6 of Fig. 5;

Fig. 7 is a fragmentary sectional View, taken approximately on the line 1-1 of Fig. 5;

Fig. 8 is a fragmentary cross-sectional view, on anenlarged scale, through the headstock, taken approximately on the line 8-8 of Fig. 1;

Fig. 9 is a longitudinal sectional view, taken approximately on the line 9-9 of Fig 8; I r

Fig. 10 is a left-hand end elevation of the headstock as shown in Fig. 9;

Fig. 11 is a horizontal sectional view, taken approximately on the line lI-l l of Fig. 10;

Fig. 12 is a fragmentary rear elevation of the wheel feeding mechanism, taken approximately on the line l2|2 of Fig. 2;

Fig. 13 is a fragmentary cross-sectional View, on an enlarged scale, of the manually operable table positioning or traversing mechanism, taken approximately on the line l3i3 of Fig. 1;

Fig. 14 is a fragmentary plan view showing. the relative positions of the grinding wheel and the Work piece;

Fig. 15 is a fragmentary plan view of the wheel slide, showing the vertical pivot therefor and the horizontal angular adjusting mechanism; and s Fig. 16 is a longitudinal sectional view, taken approximately on the line I6l6 of Fig. 13.

A helix grinding machine has been illustrated in the drawings comprising a base !5 which sup-v ports a longitudinally traversable work supporting table It on the usual V-way ll and'fiat way l8 which are formed on the upper surface of the base It. The table It supports a swivel table l9 which is arranged to swivel about a stud 2i] which is fixed relative to the table I6.

A grinding wheel 25 is supported at one end of a rotatable spindle 26 which is journalled in suitable bearings in a wheel slide 21. The grinding wheel 25 and its supporting spindle -26may be rotated in any suitable manner such as, for example, an electric motor 28 mounted on the upper surface of the wheel slide 21. The motor 28 is provided with a pulley 29 which is connected by means of a driving belt 36 with a pulley 3| mounted on the opposite end of the wheel spinole-26.

The wheel slide 21 is supported on a transverse ly movable slide 32 which is arranged to move transversely on a V-way 33 and a flat way 34 formed on a wheel slide base member 35. The wheel slide 21 is preferably pivotally connected to the cross slide 32 so that the axis of the grinding wheel spindle 26 may be adjusted in a vertical plane so that it lies at an angle to the axis of the work piece being ground. The cross slide 32 is provided with integrally formed brackets 36, only one of which has been shown in Fig. 4, which support a rock shaft 31. The Wheel slide member 21 is provided with outwardly extending bosses 38 which are journalled on the pivot shaft 31 so that the wheel slide 21 may be rocked relative to the shaft 31. The rock shaft 31 is preferably arranged in a horizontal position so that the wheel spindle 26 may be adjusted in a vertical plane into the desired angular position rela- To facilitate accurate adjustment of the slide 2'! relative to the cross slide 32, the cross slide 21 is provided with a pair of outwardly extending brackets 46 and 41 which serve as a support for a sleeve 48 through which passes a rod 49. The rod 49 passes through elongated slots 59 and 5|, respectively, which are formed in brackets 52 and 53. The brackets 52 and 53 are fixedly mounted on the cross slide 32. A pair of nuts 54 and 55 are screw threaded onto the rod 49 and serve to clamp the rod 49 and the sleeve 48 in adjusted position to hold the slide 21 in its adjusted position during a grinding operation.

The cross slide 32 is provided with an outwardly projecting portion 58 having a guide block 59 fixedly secured thereon. A gauge block 60, such as the well known Johansson gauge blockyof the required thickness may be moved into position in a groove formed in the block 59, which serves precisely to locate the sleeve 48 in a position to locate the axis of the wheel in the desired angular position relative to the axis of the work piece being ground. After this adjustment has been made, the clamping nuts 54 and 55 may be tightened to lock the slide 2! in adjusted position. The angular position of the wheel spindle 26 is determined by the lead of the helix being ground. Raising the sleeve 48 by placing a gauge block 69 of the required thicknesS, the wheel spindle 26 may be accurately positioned as desired.

In grinding a helical path, such as that shown in Fig, 14, it is desirable to provide a pivotal adjustment for the grinding wheel whereby the axis of the wheel spindle 26 may be adjusted angularly in a horizontal plane. In order to provide such an adjustment, the wheel slide base 35 is preferably pivotally connected to the base l5 by means of a vertically arranged pivot stud 62 (Figs. 2, 3 and 13). To facilitate angular adjustment of the wheel slide base 35, the machine base i5 is provided with two fixed upwardly extending brackets 63 and 84 (Fig. which are provided with adjusting screws 55 and 68, respectively. The wheel slide base 35 is provided with an index pointer 61 and the base l5 of the machine is provided with a graduated scale 58. By manipulation of the adjusting screws 65 and 66, respectively, the wheel slide base 35 may be swivelled about the pivot stud 62 in a horizontal plane to produce the desired horizontal angular position of the wheel spindle 26.

Wheel feed A wheel feeding mechanism is provided to move the grinding wheel 25 and its supporting slide 21 together with the cross slide 32 transversely to produce the desired grinding action. In order to facilitate a horizontal angular adjustment of the wheel slide base 35, the wheel feeding mechanism is preferably supported by the wheel slide base 35 so that the mechanism is always maintained in a predetermined relationship with the cross slide 32.

The cross slide 32 supporting the wheel slide 21 is provided with a depending half nut 19 which meshes with or engages a rotatable cross feed screw H journalled in a slidably mounted bearing 12 at one end and a bearing 13 (Fig. 2) at the other end. The bearings '12 and 13 are supported on the wheel slide base 35 and arranged to swivel therewith when the base 35 is adjusted angularly. The forward end of the feed screw H is slidably keyed to a rotatable sleeve 14 which supports a gear 15. The gear 15 meshes with a gear 16 supported by a rotatable shaft 11 which is journalled in bearings 18 and 19 which are supported by the wheel slide base 35.

The feed screw II is arranged to be rotated by means of a manually operable feed wheel which is supported on the end of a rotatable shaft 8| which is in turn supported by a bracket 82 fixedly mounted on the front of the base [5. The shaft 8| carries a gear 83 which meshes with a gear 84. The gear 84 is supported on the forward end of a rotatable shaft 85 journalled in a suitable bearing within the housing 86 which is fixedly mounted on the base l5. To facilitate a feeding movement in any angular adjustment of the wheel slide base 35, a universal driving connection is provided between the shaft 11 and the shaft 85. A universal joint 81 is mounted on the forward end of the shaft 11 and a universal joint 88 is mounted on the inner end of the shaft 85. The universal joints 81 and 88 are connected by a telescopic drive shaft 89. It will be readily apparent from the foregoing disclosure that a rotary movement of the manually operable feed wheel 80 will be transmitted through the mechanism above described to rotate the feed screw H to produce a transverse feeding movement of the cross slide 32 in any adjusted angular position of the wheel slide base 35. The feed screw H may be rotated by a manual operation of the feed wheel 89 or it may be intermittently fed by a pawl and ratchet feed mechanism to be hereinafter described.

In order that the wheel slide 2! and its supporting cross slide 32 may be moved rapidly toward and from a grinding position automatical ly, the feed screw H is connected through the slidably mounted, non-rotatable bearing member 12 wtih one end of a piston rod 92. A fluid pressure cylinder 93 is arranged in axial alignment with the feed screw H and is also supported on the wheel slide base 35. The cylinder 93 contains a slidably mounted piston 94 which is connected with the piston rod 92. A fluid pressure pump 95 which is driven by an electric motor or other suitable drive (not shown) serves to pump fluid through a pipe 96 from a reservoir 91 formed within the base I5. The pump 95 forces fluid under pressure through a pipe 98 to a main control or feed control valve 99.

The main control valve 99 is preferably of a piston type comprising a valve stem I having formed integrally therewith a plurality of valve pistons IOI, I02, I03 and I04 which form a plurality of valve chambers therebetween. In the position of the valve 99 (Fig. 2), fiuid under pressure passing through the pipe 98 enters a valve chamber located between the valve pistons I02 and I03 and passes out through apassage I05 into a cylinder chamber I06 to cause the piston 94 to move rapidly toward the right (Fig. 2) to cause a rearward movement of the cross slide 32 together with the wheel slide 21 and the grinding wheel 25. During the passage of fluid under pressure into the cylinder chamber I06, fluid is exhausted from a cylinder chamber I01, through a passage I08, into a valve chamber located between the valve pistons IOI and I02, respectively, and out through a pipe I09 which exhausts into the reservoir 91. A speed control or throttle valve 90 (Fig. 2) is provided in the pipe line I09 by means of which the speed of movement of the piston 94, the cross slide 32 and the grinding wheel 25 may be regulated as desired. 7 v e The valve stem I00 is normally held in a rearward feeding position (Fig. 2) by means of a spring II 0. An electric solenoid III is provided to shift the valve stem I00 toward the left (Fig. 2) into a forward feeding position. The solenoid I I I is conected by means of a link I I2 and a stud II3 to the lower end of a pivotally mounted lever II -3. The lever H4 is pivotally supported by means of a stud I I 5 which is carried by a bracket I I6 fixedly mounted relative to the base I5. The upper end of the lever H4 is operatively connected to a valve actuating red I I1. To facilitate actuation of the valve 99 in any position of the wheel slide base 35, a universal joint H8 is provided between the rod II I and the valve stem I 09. It will be readily apparent from the foregoing disclosure that when the solenoid IE! is energized, the lever I M will be rocked in a c'ounterclockwise direction to move the valve stem I09 toward the left (Fig. 2) so that fluid under pressure passing through the pipe 90 into the valve chamber between the valve pistons I02 and I03 will pass through the passage I08 into the cylinder chamber IliI to produce a forward feeding movement of the piston 94 and the feed screw 'II which in turn transmits a forward feeding movement through the half nut I0 to the cross slide 32, the wheel slide 21 and the grinding wheel 25.

Dash pot-Feed control The piston and cylinder mechanism above described serves to cause the grinding wheel 25 rapidly to aproach or recede from the work piece. In order to reduce the rapid approaching movement to a predetermined grinding feed, it is desirable to provide a wheel feed regulator or controlling mechanism, such as a dash pot mechanism, which may be rendered effective when the grinding wheel 25 is about to contact with the surface of the work piece being ground. As illustrated in Fig. 2, an outwardly projecting casing I20 is fixedly mounted on the head of the cylinder 93 and contains a pair of diametrical-1y spaced dash pot pistons I2I and I22. The dash pot pistons I2I and I 22 are normally held in a rearward position by means of springs. During the rapid approach of the grinding wheel 25, the dash pot pistons are inoperative.

The piston rod 92 extends toward the rear of the machine and is provided at its outer end with a sleeve I23 which may be adjusted'longitudinally relative to the extended portion of the piston rod 92. The parts are so arranged that thesleeve I23 'mov'es rearwardly when the piston rod 92 moves toward the rear. The dash pot pistons I2I and I22 are limited in their rearward movement by means of a flanged plate I24 which is supported on one end of the sleeve I23. An adjusting screw I25 serves to limit the rearward movement of the plate I24 and thus serves to limit the rearward movement of the dash pot pistons I2I and I22 under the influence of their respective springs.

When fluid under pressure is admitted to the cylinder chamber I0! to cause the grinding wheel 25 to move toward the work piece, the rapid approaching movement thereof continues until the sleeve I23 picks up the plate I24, which engages the ends of the dash pot pistons I2I and I22, respectively. The continued movement of the piston 94 toward the left (Fig. 2) is resisted by the dash pot pistons I2I and I 22, respectively, which force fluid under pressure from the dash pot chambers I26 and I2! into a reservoir I28. The dash pot chambers I26 and I21 are prefer ably interconnected with each other and are ar-' ranged to exhaust fluid therefrom through a needle valve I29 or an adjustable throttle valve I 38 into the reservoir I 28'. The throttle valve I39 is preferably located on the front of the machine base so that it may be readily adjusted from the operators control station.

Positive stop In order to grind a work piece to a predetermined size, it is" necessary to feed the grinding wheel 25 toward the work piece to grind the same and then to stop the infeed and allow the grinding wheel to grind out or allow the sparks to die out in order to round up the surface of the work piece to a predetermined shape and size. As illustrated in Fig. 2, the forward movement of the piston rod 92 causes a rapid approaching move ment unti the sleeve I23 picks up the dash pot pistons I2! and I22 to cause aslow infeed which continues until an adjustable collar I3I adjustahly supported on the sleeve I23- engages a fixed surface I32 on the rear ofthe casing I20, thereby positively limiting the infeeding movement of the grinding wheel 25 and causing the wheel to dwell in contact with the work during the finish grinding period. The adjustable stop collar I3I' surrounds the sleeve I23 and is held in adjusted position thereon by means of lock nuts I33.

The throttle valve I30 is connected by a pipe I35 with the reservoir I28. The pipe I35 also connects the reservoir I28 to a ball check valve I36 which remains closed during the forward feeding movement of the grinding wheel but which opens upon the rearward movementof the grinding wheel 25 as the dash pot pistons I2I" and I22 move to a rearward position to allow quick return of fluid to the dash pot chambers 25 and 2?, respectively.

The dash pot mechanism is normally an independent fiuid mechanism during the normal operation of the machine. In order readily to fill the reservoir I 28 to maintain the desired quan ti-ty of fluid therein, a pipe I3? is connected between the pump 35 and the reservoir I28. A valve I38 is located in the pipe line I3? to corn trol the flow of fluid therethrough. An overflow pipe I39 is connected between the vertically extending portion of the reservoir and the main reservoir 91 within the base I5 of the machine so that in case the fluid within the reservoir I28 rises above the desired level, the excess fluid will return directly to the reservoir within the base of the machine.

Ordinarily the valve I38 is manually opened when it is desired to fill the reservoir I28 and then remains closed during the normal operation of the machine. If desired, however, in order to insure the fluid level within the reservoir I28 at all times, the valve I38 may be opened partially so that there will be a continuous flow of fluid into the reservoir I28, and in this case the overflow pipe I39 serves to prevent the fluid level in the reservoir I28 rising above the desired point.

Automatic infeed It is desirable to provide a suitable automatic infeeding movement of the grinding wheel 25 which operates in timed relation with the traversing movement of the table I 6. In the preferred form a table actuated pawl and ratchet mechanism is provided comprising a ratchet wheel I45 (Figs. 6 and '7) which is fixedly mounted to rotate with the feed wheel 88. An oscillatable pawl carrying'member I46 is rotatably supported on a hub portion I41 of the ratchet wheel I45. The pawl carrying member I46 supports a pivotally mounted pawl I48 on a stud I49 which is fixed to the pawl carrying plate I46. The pawl carrying plate I46 is provided with a downwardly extending arm I55 which is connected by means of a stud I5I with a link I52. The other end of the link I52 is connected by means of a stud I53 with a lever I54. The lever I54 is fixedly mounted on the end of a rock shaft I55 which is rotatably supported in a bracket I56. The bracket I56 is fixed to a housing I51 which surrounds the ears 83 and 84. A lever I58 is fixedly mounted on the other end of the rock shaft I55 so that the lever I54, the rock shaft I55, and the lever I58 (Fig. 7) function as a bell crank lever. The arm I58 carries a stud I59 which supports an actuating roller I60 which is arranged in the path 4 of a feed dog I6I which is adjustably supported by a T-slot I62 formed in the front edge of the table I6. A spring I63 is interposed between a stud I64 fixedly mounted on the housing I51 and a stud I55 which is fixedly mounted on the link I52. The spring I63 serves normally to move the link I52 in a direction toward the left (Fig. 5) so that an adjustable stop screw I66 carried by the pawl carrying member I46 is normally held against a fixed abutment I61 which is supported on the housing I51. When the table I6 moves toward the right (Figs. 1 and 2), the cam face on the dog I6I serves to depress the roller I60, thus rocking the shaft I55 and the arm I54 to move the link I52 toward the right (Fig. 5), which movement serves to rock the pawl carrying member I46 in a counterclockwise direction so that the pawl I48 turns the ratchet wheel I45 to produce a rotary movement of the feed screw 1I so as to cause an infeeding movement of the grinding wheel 25. When the table I6 moves toward the left so that the dog I6! rides out of contact with the roller I60, th re leased tension of the spring I63 serves to move the link I52 and the pawl carrying member I46 in a clockwise direction, during which movement the pawls I48 ride idly over the ratchet teeth on the ratchet wheel I45. By adjusting the position of the stop screw I66, the extent of oscillating movement of the pawl carrying member I46 may be varied as desired so as to pick up the desired number of teeth on the ratchet wheel I45 each time the feed dog I H moves into an operative position.

Table traversing mechanism In order to grind a helical groove in a work piece, it is desirable to provide a suitable table traversing mechanism which is arranged so that the table traversing movement may be readily synchronized with the work rotation. In the preferred construction, as illustrated in the drawings, a rotatable lead screw I15 is supported underneath the table I6 by means of bearings I16 and I11 which are either formed integral with or fixedly mounted on the under surface of the table I6. The outer end of the lead screw I15 is provided with a sprocket I18 which is connected by a link chain I19 with a headstock mechanism to be hereinafter described. The lead screw I15 passes through a normally stationary rotatable nut I 89. The nut I88 is contained within a casing I 8| which is fixedly mounted to the base I 5. The nut I is held against endwise movement by a pair of end thrust members I82 and I83 which are adjustably fixed in the ends of the casing I8I. During the power traversing movement of the table I6, the nut I86 is held against rotation in a manner to be hereinafter described so that when the lead screw I15 is rotated through the nut I80, the table l6 together with the lead screw I15 will be moved endwiseto traverse the work piece relative to the grinding wheel.

Hand traverse adjustment In setting up the machine or in adjusting the table relative to the wheel, it is desirable to provide a suitable micrometer adjusting mechanism whereby the table I6 may be manually adjusted, accurately to position a work piece in the desired relationship with the grinding wheel 25 so that the grinding wheel may be readily aligned with the spiral path formed in the periphery of the work piece. The nut I80 is provided with an integral worm gear I 84 (Fig. 16) which meshes with a worm I85. The worm I85 is mounted on the inner end of a rotatable shaft I86 which is journalled in a bearing I81 fixedly mounted relative to the base I 5. The forward end of the shaft I86 is supported in bearings I88 and I89 formed in a housing I90 which is fixedly supported on the front of the machine base. A gear casing I9I is formed integral with the bracket I90. A gear I92 is mounted on the forward end of the shaft I86 and meshes with a gear I93 which is rotatably supported on a stud I94 carried by the housing I9I. A manually operable hand wheel I95 is fixedly mounted to rotate the gear I 93 when desired to transmit a rotary movement to the nut I80.

The hand wheel I95 is normally held stationary by means of a spring-pressed index stud I96 which is arranged to engage any one of a plurality of index holes I91 formed in a circular path in a cover plate I98 fastened to the housing. I9I. When it is desired to rotate the hand wheel I95, a knob I99 is pulled toward the operator to disengage the looking or index stud I96 from the apertures I91 and the hand wheel I95 may then be readily rotated as desired.

In order that the table may be precisely adjusted, the gear mechanism between the hand wheel I95 and the nut I80 is preferably such that the rotation of the hand wheel to pass the indexing stud I96 from one hole to the next serves to advance or traverse the table I6 by a precise amount, for example .0005. Thg amount of advance between index holes maybe varied as desired by varying the gear ratio between the hand Work supporting and rotating mechanism The work piece to be ground may, if desired,

be supported by a head and footstock mechanism, 1

such as is utilized in common practice in the old and well known cylindrical grinding machines. In the preferred construction, however, a work piece 205 is rotatably supported in a special fixture 206. The fixture 206 is supported by a transversely movable slide 201 which is adjustable transversely relative to the table I6 on a dovetailed slideway 208. A nut and screw mechanism (not shown) may be provided precisely to adjust the slide 20'! and the fixture .206

transversely relative to the table Hiso as to align the axis of the work piece 205 into substantial alignment with a headstock spindle 209 which is rotatably supported in a headstock2l0. A uni-.- versal driving connection 2| I is provided between the headstock spindle 209 and the end of the work piece 205 uniformly to rotate the work piece 205 even though its axis of rotation may be slightly out of line with the headstock spindle 209. The headstock spindle 209 is rotatably supported in bearings H2 and 2 l3 which are fixedly mounted within the headstock 2 l 0.

To facilitate an efficient grinding operation, it is desirable that the work and wheel traverse relatively at a normal grinding speed while the work is rotated at a grinding speed, after which the wheel recedes to an inoperative or rearward position and the wheel and work piece are traversed longitudinally on the return stroke at a rapid rate to cut down theidle time. It is desirable that the grinding operation proceed while 225 and 225 which are fixedly mounted in the headstock 2 I0.

the work is traveling in one direction only since there is more or less backlash in the operating parts and it is necessary to return the work and wheel to an initial position and to take up all I of the backlash beforethe wheel is brought into operative engagement with the work for the next grinding pass.

The headstock driving-mechanism is arranged not only to drive the headstock spindle 209 but also synchronously to drive the lead screw I15 to traverse the table l5 so that the headstock spindle 209 and the lead screw [15 are at. all times synchronously rotated. A driving motor 2l5 is mounted on the headstock 2l'0. The motor 2|5 is provided with a pulley 2l6 which is connected by means of a multiple V-belt 2 l I with a pulley 2l3 mounted on the outer end of the rotatable shaft 2l9. The shaft 2E9 is rotatably supported in the headstock 210 in bearings 220 and 22!. The shaft 2l9 supports a worm 222 which meshes with a worm gear 223 mounted on a transversely extending rotatable shaft 224'.

The shaft 224-is rotatably supported in bearings In order to drive the headstock spindle 209 at a grinding speed on the operative stroke, the shaft 224 is provided with a left-hand worm 228 which meshes with a worm gear 229 which is rotatably mounted on a rotatable shaft 230 which is journalle'd in bearings 23l and 232' in the headstock 2I0. The side of the worm gear 229 is provided with clutch teeth'233 which are arranged to be engaged by clutch teeth on a slidably mounted clutch member 234 which is slidiably keyed on the shaft 230 by means of a key 235. It will be readily apparent from the foregoing disclosure that when the clutch member 234 is moved toward the right (Fig. 9) so that the teeth on the member 234 engage the teeth 233- on the worm gear 229, any rotary motion of the worm gear 229 will be transmitted to rotate the shaft 230. The shaft 230' is provided with a driving sprocket 236 which is connected by means of a link chain 231 with, a sprocket 230 which is keyed onto the headstock spindle 209 so that rotary motion of the shaft 230 will be trans,- mitted to rotate the headstock spindle which in turn transmits a rotarymovement to rotate the work piece 205.

In order to drive the feed screw H5 in timed relation with or synchronized with the. headstock spindle 209, a suitable driving mechanism is provided comprising a sprocket 24.0 (Figs. 8 and 9) mounted on the end of the headstock spindle 209. The sprocket 240. is connected by means of a link chain 24I with a sprocket 2'42 (Figs. 8, 9 and 10) which ismounted on the outer end of a rotatable shaft 243.. The shaft 243v is journalled in bearings 244 and 2'45 which are fixedly mounted in the headstock 2H0. A sprocket 246 is keyed to the shaft 243 and is connected by means of the link chain I19 with the lead screw I15 to rotate the lead screw H5 in syn chronism with the headstock spindle 209.

Anadjustably mounted rotatable idler 248 is mounted on a stud 249 which iscarried by means of a bell cranklever 250. The bell crank lever 250 is pivotally supported on a stud 25l WhlCh'lS fixedly mounted on the headstock 2H1. An adjusting screw 252 which is cooperatively connected by means of a stud 253 with one end of the bell crank lever 250 serves to facilitate'ad-v justment of the idler 248 to take upthe slack in-the link chain 24l. v

A rotatable idler 255 supported on, a: stud 255. which is fixedly mounted on an adjustablebracket 25'! supported on the headstockjlll servesto take up the slack in the link driving chain I19 to facilitate synchronizing the'rotation' of the wheel spindle 209 with the table lead screw I 75. The bracket 2-51 is provided with elongated slots 258 and 259. Clamping screws 269' and 261 (Fig. 10) pass-through the elongated slots 258' and 259; respectively, and are screw threaded into the frame of the headstock 2J0 andserve to clamp the bracket 259 in adjusted. position after the bracket and idler'255 have been moved to properly tension the driving chain H9;

To facilitate driving the leadscrew rapidly-in the reverse direction, a right-hand worm 265 (Figs. 8 and 11) is fixedly mountedion the. shaft 224. The worm 2'05 meshes witha worm .gear 266 which is rotatably mounted on the.shaft. 2'43. The worm gear 266 is provided with clutch teeth 26.! which are arranged to engage, clutchteeth formed on the slidably mounted". clutclrmember 268. The clutch member 268 is slidably keyed on the shaft 243. When the clutch member 268 is moved upwardly (Fig. 11) so that its clutch teeth engage the clutch teeth 261, the worm gear 266 will be clutched to rotate the shaft 243 at a comparatively fast speed. The rotation of the shaft 243 will transmit a rotary movement through the link chain 24I to rotate the headstock spindle 209 at a comparatively fast speed in the reverse direction. At the same time, the rapid rotation of the shaft 243 will be transmitted through the sprocket 246 and the link chain I19 to rotate the sprocket I16 and the lead screw I15 at a comparatively rapid rate in the reverse direction to traverse the table I6 through an idle or return stroke to its initial starting position.

The slidable clutch members 234 and 268 are preferably actuated by a common operating means so that one clutch is engaged while the other remains disengaged and vice versa. A vertically arranged rock shaft 210 is supported in a suitable elongated bearing 21I (Fig. 8) formed integral with the headstock frame 2 I 0. The lower end of the shaft 219 is provided with yoke-shaped arms 212 and 213 which support studs 214 and 215 which ride within a groove 216 formed in the clutch member 234. A pair of yoke arms 211 and 218 are formed integral therewith and are provided with studs 219 and 280, respectively, which are arranged to engage a groove 28I formed in the periphery of the clutch member 268. It will be readily apparent that when the shaft 219 is rocked in a clockwise direction (Fig. 11), the yoked arms 211 and 218, through the pins or studs 219 and 280, will shift the clutch member 268 upwardly to engage with the clutch teeth 261 formed on the worm gear 266 so as to rotate the headstock spindle 209 and also the table operating lead screw I15 in' a reverse direction at a comparatively rapid rate which continues during the return stroke of the work supporting table I 6. Similarly, when the shaft 210 is rocked in a counterclockwise direction (Fig. 11), the yoke arms 212 and 213 through the pins or studs 214 or 215, respectively, will shift the clutch member 234 upwardly (Fig. 11) to engage it with the teeth 233 formed integral with the gear 229 to rotate the headstock spindle 209 at a grinding speed and synchronously to rotate the table operating lead screw I15 to traverse the table I6 in synchronized relationship with the rotation of the work piece 295 at a normal grinding speed. At the same time the clutch 234 is thrown into engagement with the clutch teeth 233, the clutch member 268 is thrown out of engagement with the clutch teeth 261. V

In order that the cycle of operation may be automatic, it is desirable to actuate the clutch shifting shaft 219 in timed relationship with the other moving parts of the machine. In the preferred form, a hydraulically operated actuating mechanism is provided comprising a fluid pressure cylinder 285 (Figs. 1, 3, 8 and 9) which is mounted on top of the headstock 2I0. A piston 286 (Figs. 3 and 9) is slidably mounted within the cylinder 285. A piston rod 281 is fixedly connected to the piston 286. The other end of the piston rod supports an adjustably positioned stud 288 (Fig. 9) which is connected by means of a lever 289 which is fixedly mounted on the upper end of the clutch shifting rock shaft 210.

As illustrated in the drawings, the clutch actuating cylinder 285 is preferably hydraulically connected with. the wheel feed cylinder 93. A pipe 390 is connected between'the valve chamber I06 in the feed cylinder 93 and a cylinder chamber 29I formed in the left-hand end of the cylinder 295 (Figs. 3 and 9) to cause the piston 286 to move toward the right, which movement serves to rock the shaft 219 in a clockwise direction (Fig. 11) to throw the clutch member 268 into engagement with the teeth 261 on the gear 266 to rotate the headstock spindle 209 and the lead screw I15 rapidly in a reverse direction to start the table traversing on its idle stroke to return the work piece to the initial position. The pipe 299 is arranged so that when the fluid under pressure flowing to the wheel feed cylinder 93 is reversed, the piston 94 will move rearwardly a suflicient distance to withdraw the wheel 25 from within the groove in the work piece before the piston 94 uncovers the pipe 290 to shift the clutch member 298 and start the return table movement. Similarly, when fluid under pressure is admitted through the passage or pipe I08 to initiate a forward feeding movement of the piston 94, fluid under pressure is also passed through a pipe 292, into a cylinder chamber 293 at the right-hand end of the cylinder 285, to cause the piston 286 to move toward the left (Figs. 3 and 9), which movement serves to rock the shaft 219 in a counterclockwise direction to throw the clutch member 234 into engagement with the clutch teeth 233 and to disengage the clutch member 268, thus traversing the table I6 at a normal grinding speed which is synchronized with the rotation of the headstock spindle 209 which also is rotating at the normal work speed for the given grinding operation.

The various moving parts of the machine are interlocked and controlled by an electrical control system. A pair of switches 295 and 296 (Fig. 3) contained within a housing 291 (Fig. 2) are supported by a bracket 298 which is in turn fixedly supported on the end of the dash pot frame I20. The switches 295 and 296 are arranged to be actuated by an adjustably mounted bracket 299 which is adjustably supported on a threaded end portion 390 of the piston rod 92. The bracket 299 supports a longitudinally extending member having a T-slot 30I formed therein which supports a pair of adjustably mounted dogs 302 and 303 (Figs. 2 and 12) which are arranged respectively to engage the lever arms 394 and 305 which are formed integrally with a hub member 396. The hub 396 is fixedly supported on a rock shaft 301 which serves simultaneously to actuate the switches 295 and 296. The switches 295 and 296 are connected and arranged so that one of the switches is closed while the other is opened. The switches 2'95 and 296 are arranged'so that when the wheel slide is in a rearward position, the switch 295 is closed and the switch 296 opened. Similarly, when the wheel slide moves forward to position the grinding wheel 25 in an operating position, the switch 293 closes and the switch 295 opens.

The work and table driving motor 2I5 is preferably a variable speed, reversible type motor. This motor is controlled by means of a starter switch 3'I9 illustrated diagrammatically in Fig. 3. The motor is controlled by two magnetic starter switches, namely a magnetic starter switch 3 for rotating the work in a normal grinding direction and traversing the table therewith. A second magnetic switch 3I2 is connected so as to rotate the motor and traverse the table in the reverse direction.

In the preferred construction, it is desirable .321 and a normally closed contactor 328.

that a jogging mechanism be provided whereby the table I may be jogged longitudinally to ac-' curately position the work piece in the desired relationship with the grinding wheel. A manually operable momentary contact jog switch 3I5 is connected in series with a limit switch 3I6 located adjacent to the right-hand end of thebase 15. The limit switch 3IB is in turn connected to actuate the forward magnetic switch 3 to jog the motor 2E5 so as to adjust the position of the table. It longitudinally toward the right relative to the grinding wheel 25.

Similarly, a momentary contact jog button 3!? is connected in series with a limit switch 3I8 which is connected to actuate the magnetic switch 3I2' to jog the motor M5 in the reverse direction so as to jog the table I6 toward the left to facilitate accurately positioning the table it longitudinally relative to the grinding wheel in a direction toward the left. The jog buttons 3I5 and 311 are preferablyinterconnected with an automatic cycle control switch 320 so that when the switch 329 is set for an automatic grinding cycle, the jog buttons 3I5 and 3I'I are rendered inoperative. The limit switches 3I5 and 3I8 are arranged in the path of fixed dogs 32I and 322 on the table I6 which serve asvsafety devices to stop the traversing movement of the table It before either the bearing H5 or the bearing IT! moves into engagement with the housing ISI surrounding the nut I80.

A double contactor limit switch 323 is mounted on the front of the machine base. This switch is a normally closed switch and is arranged automatically to be opened by means of an adjustable table dog 324 when the table It moves to its lefthand end position at the end of the grinding operation. Similarly, a double contactor limit switch 325 is mounted on the front of the machine base and is arranged to be actuated by .means of an adjustable table dog 326. The switch 325 contains a normally open contactor When the dog 326 moves toward the right with the table I5 and actuates the switch 325, the contact 321 is closed and simultaneously therewith the contactor 328 is opened.

A start snap switch 333 is provided for initiating a starting of the grinding cycle. When the starting switch 330 is closed, the machine will continue to go through the cycle of operation and will then repeat the cycle until the starter snap switch 330 is actuated to open the circuit and stop the cycle of operation after it has completed its cycle.

The operation of the improved helix grinding machine will be readily apparent from the foregoing disclosure. Assuming all of the parts to have been previously adjusted and a new work piece 285 is in operating position on the supporting fixture 226 and the grinding wheel 25 is shown at its inoperative position where it stops at the end of a complete grinding cycle, the cycle of operation is started by actuation of the cycle control start switch 330 to close a circuit. In this position the slide 32 is in its rearmost or inoperative position and the closing of the cycle control switch 330 serves to actuate the magnetic starter switch 3! I which through the starter control mechanism 3!!) serves to start the headstock motor 2i5 to traverse the table It longitudinally toward the right at a high speed. The high speed clutch is in operative engagement due to the fact that the slide 32 is in its rearmost position. The

table I 6 travels rapidly toward the right until the table dog 326 .actuates the limit 'switchi325 to close the switch 321 which serves through a magnetic switch 332 to energize the solenoid I II which shifts the feed control valve 99 into its reverse position to initiate a forward feeding movement of the grinding wheel 25. At the same time the switch 321 closes to initiate a forward feeding movement, the switch 328 opens to open the magnetic switch 3i I which serves through the starter control 3 i ll to stop rotation of the head stock motor 2 I 5 which stops the rotation of the work piece 235 and also stops thelongitudinal movement of the table I6.

When the solenoid IiI is energized and the valve shifts upwardly to admit fluid under pressure through the pipe or passage I08 into the cylinder chamber I07. to initiate a forward movement of the piston 94, fluid under pressure is also passed through the pipe 292, into the cylinder chamber 233, to move the piston 285 toward the left which serves to rock the shaft 210 in a counterclockwise direction (Fig. 11) to throw the slow speed clutch member 234 into engagement with the teeth 233 so that the rotation of the motor 2I5 'willbe transmitted through the worm 228 and the worm gear 229 to rotate the head-stock spindle 239 and also the lead screw H5 at a normal grinding speed. When the spindle 239 and lead screw I15 are first rotated to start rotation of the work at a normal grinding speed and to start the table I5 traversing at a grinding speed in .synchronism with the rotation of the work piece 205, the backlash in the driving mechanism is taken up so that when the grinding wheel 25 comes into contact with the work piece, the wheel will engage the work :piece to grind the spiral path, as indicated. The traversing movement of the table I6 toward the left continues until the grinding wheel 25 grinds to the end of the spiral path on the work piece, at

which point the adjustabl table dog 324 opens the limit switch 323 which serves through the magnetic switch 332 to deenergize the wheel feed solenoid III to allow the released compression of the spring IIG .to return the feed control valve 93 into the position illustrated in Fig. 3. At the same time, the opening of the limit switch'323 serves through the magnetic switch 3 to break a circuit which serves through the starter 3H! to stop the rotation of the motor 2I5 which in turn stops the rotation of the work piece 255 and also the traversing movement of the table Iii. The

deenergizing of the solenoid II I and the shifting of the valve 99 serves to admit fluid under pressure to move the piston 94 rearwardly into the position illustrated in Fig. 3, which movement serves to admit fluid under pressure through the ping the entire cycle of operation. Unless the starter switch 333 is actuated to break the circuit, the cycle of operation will be repeated indefinitely until the switch 333 is shifted to break the circuit, thus making several grinding passes of the work 235 across the face of the grinding It should be noted. that the .wheel piece.

265 only during the travel of the table I6 toward the left and that upon the return stroke of the table I6 toward the right at a rapid rate, the wheel 25 in its rearward or inoperative position thus makes an idle rapid pass of the work piece to position the work for the next grinding pass.

In the position of the switch 320, the circuit is closed for an automatic grinding cycle. In setting up the grinding machine for grinding a given work piece, it may be desirable to jog the table I6 longitudinally in either direction to adjust the position of the work piece 205 relative to the grinding wheel 25 so as to align the wheel with the helical path to be ground on the work In such a case the switch 320 is actuated to open the upper switch contacter (Fig. 3) and to close the lower contacter. The closing of the lower contacter of switch 320 (Fig. 3) serves to render the jogging buttons 3I5 and 3I'I operative. In this position of the switch 326, if it is desired to jog the table I6 toward the right, the push button jog switch 3I5 is closed which serves through the magnetic switch 3| I and the starter control mechanism 3I0 to start the motor 2I5 to move the table I6 toward the right. The push button 3I5 remains closed only so long as the operator holds it closed, thus enabling the operator to jog the table I6 by any desired amount to position the work piece relative to the grinding wheel 25. If it is desired to jog the table I6 toward the left, the jog button switch 3I'I is closed which serves through the magnetic switch 3I2 and the starter control mechanism 3I0 to start the motor 2I5 in the reverse direction to jog the table I6 toward the left the desired amount. The jog button 3I6 is closed only so long as the operator holds it closed, thus facilitating a manually controlled adjustment of the table I6 to position the work piece 265 relative to the grinding wheel 25. When it is desired to start the grinding operation, the switch 320 is again actuated to close the upper contacter and open the lower contacter so that the automatic cycle is then rendered effective.

The switch 295 (Fig. 3), which is actuated by the wheel feed mechanism, is .shown closed and serves to close a circuit to shunt the limit switch 323 when it is in an open position, as shown in Fig. 3, so that the grinding operation may be started only when the grinding wheel is in its extreme rearward position.

The limit switch 296, which is also actuated in timed relation with the wheel feeding movement, serves to start rotation of the work piece 205 and a traversing movement of the table I6 only when the wheel slide 2'! and the grinding wheel 25 are in a forward or operating position. It will be readily apparent from the foregoing description that when the table I6 moves to its extreme right-hand end position, the actuation the work piece 265 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 successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide to support said wheel, means to feed said wheel transversely in either direction, a longitudinally traversable work supporting table, means to traverse said table longitudinally in either direction, a headstock including a rotatable spindle to rotate a work piece supported on said table, an electric motor on said headstock, driving connections including a clutch between said motor, spindle and table traversing mechanism to rotate said spindle and traverse the table in one direction at a normal grinding speed, driving connections including a clutch between the motor, spindle and table traversing mechanism to rotate said spindle and traverse the table in the opposite direction at a fast speed during an idle stroke of the table in the reverse direction, and means actuated by and in timed relation with the forward feeding movement of the wheel slide to shift the clutch to rotate the work and traverse the table at a normal grinding speed.

2. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide to support said wheel, means to feed said wheel transversely in either direction, a longitudinally traversable work supporting table, means to traverse said table longitudinally in either direction, a headstock including a rotatable spindle to rotate a work piece supported on said table, an electric motor on said headstock, driving connections including a clutch between said motor, spindle and table traversing mechanism to rotate said spindle and traverse the table in one direction at a normal grinding speed, driving connections including a clutch between the motor, spindle and table traversing mechanism to rotate said spindle and traverse the table in the opposite direction at a fast speed during an idle stroke of the table in the reverse direction, and mechanism actuated by and in timed relation with the rearward movement of the wheel slide to shift the high speed clutch so as to rotate the spindle and traverse the table at a fast speed during an idle stroke.

3. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide rotatably to support said wheel, means including a piston and cylinder to feed said slide transversely, a control valve therefor, a longitudinally traversable work supporting table, means to traverse said table longitudinally in either direction, a headstock including a rotatable headstock spindle to rotate a work piece supported on said table, an electric motor on said headstock, driving connections including a high speed clutch and a low speed clutch between said motor, spindle and table traversing mechanism to rotate said spindle and to traverse the table in the opposite direction at a fast speed during an idle stroke, and means including a piston and cylinder simultaneously to actuate both of said clutches in timed relation with the movement of said feed.

4. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide rotatably to support said wheel, means including a piston and cylinder to feed said slide transversely, a control valve therefor, a longitu dinally traversable work supporting table, means totraverse said table longitudinally in either direction, a headstock including a rotatable headstock spindle to rotate a Work piece supported on said table, an electric motor on said headstock, driving connections including a clutch between said motor, spindle and table traversing mechanism to rotate said spindle and to traverse the table at a'normal grinding speed, driving connections including a clutch between the motor, spindle and table traversing mechanism to rotate the spindle and to traverse the table in the opposite direction at a fast speed during an idle stroke, means including a piston and cylinder simultaneously to actuate both of said clutches in timed relation with the movement of said feed, and fluid connections between the feed cylinder and clutch cylinder, whereby the high speed clutch is engaged when the grinding wheel is moved rearwardly to an inoperative position and the low speed clutch is engaged when the grinding wheel is moved toward an operative position.

5. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide to support said wheel, means to feed said wheel slide transversely in either direction, a longitudinally traversable work supporting table, a headstock including a rotatable spindle, an electric motor on said headstock, driving connections including a clutch between said motor and spindle, and means actuated automatically by and in timed relation with the transverse movement of the wheel slide to actuate said clutch to start rotation of said spindle at a normal grinding speed when the wheel slide is moved to an operative position.

6. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide to support said wheel, means including a piston and cylinder to feed said wheel slide transversely in either direction, a longitudinally traversable work supporting table, a headstock including a rotatable spindle, an electric motor on said headstock, driving connections including a clutch between said motor and spindle, means including a piston and cylinder to actuate said clutch, and fluid connections between said feed cylinder and said clutch cylinder whereby the clutch is automatically actuated to start rotation of the spindle at a normal grinding speed when fluid is admitted to the feed cylinder to move the grinding wheel into an operative position.

7. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide rotatably to support said wheel, means including a piston and cylinder to feed said slide transversely, a control valve therefor, a headstock including a rotatable headstock spindle, an electric motor on said headstock, multi-speed driving connections between said motor and said spindle including a high speed and a low speed clutch, means including a fluid pressure operated piston and cylinder to actuate said clutch-es, and fluid pressure connections between said feed cylinder and said clutch cylinder whereby the high speed clutch is engaged when the wheel slide is moved to its rearmost position, and said low speed clutch is engaged when the wheel slide is in its forward or grinding position.

8. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, means to pivotally adjust said slide about a horizontal and a vertical axis to position the grinding wheel for grinding a helical groove,

means to feed said slide transversely, a longitudi nally traversable work supporting table, means including a nut and screw mechanism to traverse said table, a headstock including a rotatable headstock spindle to rotate a work piece supported on said table, a reversible electric motor on said headstock, driving connections including a high and a low speed clutch between said motor, spindle and screw synchronously to rotate said spindle and screw either in one direction at a normal grindingspeed or in the opposite direc-- tion at a fast speed during an idle stroke and means actuated by and in timed relation with the transverse movement of the slide to actuate said clutch.

9. In a grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, means to feed said slide transversely, a longitudinally traversable work supporting table including a nut and lead screw to traverse said table, a headstock including a rotatable headstock spindle to rotate a work piece supported on said table, an electric motor on said headstock, driving connections including a high speed and a low speed clutch between. said motor, spindle and lead screw to rotate said spindle and said screw either at a normal grinding speed or at a fast speed during an idle stroke and means actuated by and in timed relation with the transverse movement of said slide to actuate said clutch.

10. In a grinding machine having a rotatable grinding Wheel, a transversely movable slid'e therefor, a longitudinally traversable work supporting table, means to feed said slide transversely, means including a nut and lead screw mechanism to traverse said table, a headstock including a rotatable headstock spindle to rotate a work piece on said table, an electric motor on said headstock, driving connections including a clutch between said motor, spindle and lead screw to rotate the lead screw and traverse the table in one direction at a normal grinding speed, driving connections including a clutch between the motor and the lead screw to rotate the lead screw in the opposite direction at a fast speed so as to traverse the, table through a fast idle stroke in the reverse direction and means actuated by and in timed relation with the transverse movement of said slide to actuate said clutch.

11. In a grinding machine having a rotatable grinding Wheel, a transversely movable slide therefor, means to feed said slide transversely, means to pivotally adjust said slide about a horizontal and. a vertical axis to position the grinding wheel for grinding a helical groove, a longitudinallytraversable supporting table, means including a nut and lead screw mechanism for traversing said table, a headstock including a rotatable headstock spindle to rotate a work piece supported on said table, an electric motor on said headstock, driving connections including a high and a low speed clutch on said headstock between the motor, spindle and lead screw synchronously to rotate said spindle and screw either in one direction at a normal grinding speed or in the opposite direction at a fast speed during an idle stroke and means actuated by and in timed relation with the transverse movement of said slide automatically to actuate said clutch.

12. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable slide therefor, means to feed said slide transversely, a longitudinally movable work supporttraverse it at a normal grinding speed as the table moves in one direction, driving connections including a clutch synchronously to rotate said spindle and screw in the reverse direction at, a fast speed While the table is traversing in the reverse direction during an idle stroke and means automatically actuated by and in timed relation with the movement of said slide to actuate said clutch.

JOHN I. GARSIDE.

Images