US2431671A - Taper grinding machine - Google Patents

Description

Dec. 2, 1947. ARMS TAPER GRINDING MACHINE 7 Sheets-Sheet 1 Filed Jan. 23, 1945 M. H. ARMS I ,4 9

'TAPER GRINDING MACHINE Filed Jan. 23, 1945 '7 Sheets-Sheet 2 Dec, 2 M ZAEHfi YE TAPER GRINDING MACHINE Filed Jan. 23, 1945 7 Sheets-Sheet 3 Dec. 2 1947,

M. H. ARMS TAPER GRINDING MACHINE Filed Jan. 23, 1945 7 Sheets-Sheet 4 Dec. 2, 1947. M. H. ARMS TAPER GRINDING MACHINE 7 sheets-sheen 5 Filed Jan. 23, 1945 lllll.

Dec. 2, 1947. M. H. ARMS TAPER GRINDING MACHINE Filed Jan. '25, 1945 7 Sheets-Sheet 6 Dec. 2, 1947. ARMS 2,431,671

TAPER GRINDING MACHINE Filed Jan. 23, 1945 7 Sheet -Sheet '7 Patented Dec. 2, 1947 TAPER GRINDING MACHINE Merton H. Arms, Springfield, Vt., assignor to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont 1 Application January 23, 1945, Serial No. 574,066

This invention relates to grinding machines adapted to grind taper work.

One object of the present invention is to provide for taper grinding with a tapered grinding wheel, means being provided by which truing of the wheel to the proper tapered contour may be eiiected.

A further object is to provide means, if desired, by which a rough grinding wheel and a finish grinding wheel may be used in succession, both wheels being carried by the same spindle, the rough wheel being removed when finish grinding is to be done, provision being made for bringing the finish grinding wheel into the same axial relation to the Work which the rough grinding wheel previously had.

A further object is to provide a single cam for controlling the motion of each of the grinding wheels when they are selectively in position, either to grind the work or to be trued, thus avoiding the difficulty of making a plurality of cams identically contoured so that the wheels may be properly trued to the same contour and presented in the same relation to the work. 7

Still another object is to provide for feeding of the wheels arranged for taper grinding by motion of the grinding wheel carriage parallel to the wheel spindle axis. By moving the wheel carriage rather than the wheel spindle, a more rigid structure is afforded.

Still another object is to provide for feed between the wheels and the work axially of the Wheel carrying spindle, together with means for automatically shifting the traverse limits in accordance with the feed and compensation for wheel wear and truing.

For a more complete understanding of this invention, reference may be had to the accompanying drawings in which Figure 1 is a fragmentary front elevation of an internal grinding machine embodying the invention.

Figure 2 is a detail sectional view on line 2-2 of Figure 1.

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

Figure 4 is a sectional view on line 44 of Figures Zand 3.

Figure 5 is a detail sectional view on line 5-5 of Figure 1, but showing a modification employing but a single grinding wheel.

Figure 6 is a detail sectional view on line-66 of Figure 2. a

Figure 6a is a fragmentary top plan view of a portion of the carrier bracket showing the camadjusting means.

20 Claims. (Cl. 51-50) Figure '7 is a detail view and in section and partly in valve actuating mechanism.

Figure 8 is a fragmentary left end elevation of the machine.

Figures 9 and 10 are diagrammatic views showing the rough grinding wheel and the reversing mechanism at its outer and inner stroke limits, respectively.

Figure 11 is a view similar to Figure 9, but showing the finish grinding wheel in use.

Figure 12 is a diagrammatic view illustrating the rough grinding wheel about to be dressed,

Figure 12a is a diagrammatic view illustrating an inoperative relation of cam and limit stop dogs partly broken away elevation of the pilot to the follower and traverse reverse mechanism,

respectively.

Figures 13 to 15, inclusive, are fluid pressure system diagrams, Figures 13 and 14 showing the carrier reverse mechanism actuating control valves for the pilot valve for moving the carriage to the left and right, respectively. Figure 15 shows the reverse mechanism directly actuating the pilot valve and in the position to start the carriage to move to the left.

The subject matter of this invention is shown as applied to a grinding machine of the type shown in my Patent No. 2,176,985, granted October 24, 1939, for Grinding machine, in which the grinding wheel is caused to traverse the work by fluid pressure. As shown best in Figures 1 and 8,

the work I is supported in a rotary spindle 2 in fixed position in the machine, while the grinding wheel spindle 3 is journaled in an arm 4 intermediate to its length, this arm 4 being suspended on a fulcrum bar 5 which embodies hydraulically operated traversing mechanism as-is shown in my patent to which reference has been made. The bar 5 is supported in spaced frame portions 6 and 1. The spindle is biased by gravity toward the work axis.

As shown best in Figure 8, the arm 4 projects below the grinding wheel spindle 3 and has fixed thereto a bracket l0 having means at its lower end cooperating with a feed mechanism by which the angular position of the arm 4 about its pivot may be adjusted and swung during the traverse of the grinding wheel and the work to provide for the desired transverse motion of the grinding wheel relative to the. work during its traverse. The means for producing thistransverse motion is specifically different, as shown herein, from that shown in my prior patent, as will later appear.

The traverse control shown herein makes use of a controlling pilot valve l2 similar to the valve 4| shown in my prior patent, but the axial motion of this pilot valve is differently controlled in the present invention and does not depend upon the rotation of the shaft 84 shown in my patent. Instead of this, pilot valve l2, as shown best in Figure 7, has an extension I5 at its right hand end recessed as at It to engage about the'head ll of a piston rod 58 of a hydraulic motor having a cylinder Hi. The cylinder l9 has a base flange secured through a plate 2| to the main valve casing 22 as by screws 23. The pistonrrod l8 as shown extends through the cylinder l9 through both cylinder heads 24 and. 25 and beyond each of these it passes through a packing 26. Within the cylinder IS the rod has a piston portion 38. Pressure and discharge pipes 3| and 32 lead into opposite ends of the cylinder l9 beyond the piston 33, and a drain pipe 33 communicates with a port 34 which enters between each of the cylinder heads 24 and Hand the adjacent packing'26 to return leakage back toa supply tank. The traversing mechanism controlledby the axial position of the pilot valve- I2 is the same as shown in my prior patent and also the angularrcontrol of the pilot valve may also be identical.

As shown best in Figuresl, and 9 to, 12, the wheel spindle 3 may carry a pairpf grinding wheels 40 and 4|. The grinding wheel -4tlymay be a finish grinding wheel and the grinding wheel M a rough grinding wheel. As shown in Figure 1, the grindingwheel 40 may be secured to the end of the shaft 3 and maybe provided with a central opening communicating-with a tapered socket 42111 the spindle endso as to permit the grindingwheel 4| to beremova-bly secured to the spindle as by means ofga tapered extension 44, which may-well 1 be of the construction shown in the Cornell and 'Williams Patent No. 2,330,686, granted September 28,1943, for Tool spindle with removable projections. This permits ready application or removal of the rough grinding wheel 4| as may be'desired, it being intended that during the rough grinding, the grinding wheel 4| be in. position, after which this grinding wheel with its projection is .removed, and the finish grinding is producedby the wheel 40.

Since the axes of the Wheel spindle 3 and the work are parallel, in order to taper grind holes in the work each of the grinding wheels is provided with a taper face portion-45, 46 which is the active portion of the wheel used for accomplishing the taper grinding, and which by continued use and truing wears down, and the corresponding diameter portions of which progress axially of the wheel toward the right hand face thereof as it is worn and trued. It will be apparent that since these taper faces 45 and 46' are at different axial positions, the rocking motion of the arm 4 during its traverse in order to produce the corresponding taper face on the work will have to be differently related to the traverses when the two different wheels are employed, and this invention makes provision for such change of axial position of the arm 4 and the wheel'spindle, corresponding to the particular wheel being used at anytime.

The following mechanism accomplishes this desired action. The;l ower forward end ofthe bracket H1 is provided with a top guide groove 5!] along which at a suitably spaced point maybe secured four reversing limitdogs 5|, 52,53 and 54,, the forward ends of which project forwardly and either pair of which 5115?. or '53and 54, may be positioned on opposite sides of a reversing 4 lever 55. This reversing lever is fulcrumed on the pin 56 secured to the upper face of a supporting carriage 5'! which may be adjusted parallel to the axis of the work and to the pivot of the arm 4, on a guide block 58. The block 53 is secured as by screws 59 to the upper face of a slide 66 mounted for movement transverse to the work axis on a supporting bracket 6| secured to a fixed frame member 62 of the machine. The slide 60 is yieldingly pulled forward toward the front of the machine as by a pair of coil springs 63, each of which is hooked at its forward end to a fixed abutment angle 64 and at its rear end to a rod 65 adjustably secured as by threading into a support 66 fixed to the slide 60. The forward limit of motion of the slide 60 is determined by the impingement of a wear piece 70 secured to the carriage 51 and engaging a roller ll J'ournaled in the forward end of a bar 12 having a threaded forward end portion 13. As shown best in Figure 6, the bar 12 is mounted for axial sliding motion througha bushing 14 extending through the fixed frame member 75, and its threaded forward extremity engages with an internally threaded sleeve 76 slidably mounted through a bushing 11 seated in a hub portion E8 of a fixed frame portion 19 spaced forwardly of the frame portion 15. The bushing H has an externally threaded forward end for the reception of a ring nut 80, which secures in position against the outer end of the hub 18, a disk at. The sleeve 16 is keyed to the bushing 17 so as to permit only relative axial motion therebetween, and the bushing 11 is keyed to the disk 8!. Thus by rotating the disk 3!, the sleeve '36 is turned and the bar 12 is caused to move axially for adjustment. This, however, is only a rough adjustment, the disk 8| being locked in one angular position thereafter by a key 853 (see Figure 2) secured by screws to the fixed hub portion 78 and engaging in a slot in the disk 8!. The sleeve I6 is provided at its outer end with an abutment plug 82 against which may contact the edge of a disk 83 eccentrically pivoted on the pin 84 between forks B5 of an element 86 secured to the outer face of the disk 8!, the disk 83 being retained in a vertical plane by the key 850. The usual fine feed is produced by axial and not transverse motion of the arm Id, this being possible by reason of the taper of the active wheel faces and this feed also adjusts in the same direction the locations of the zones of traverse defined by the spacings of the pairs of limit dogs 5| to 54, inclusive.

In the position shown in Figure 6 in full lines, the disk 83 presses the plug 82 to its inner limit of motion, the disk being held in this position by means of a handle 8'! secured thereto engaging between the sides of a spring latch 38. By turning the handle ,8], into the dotted line position, the disk 83 is turned to the dotted line position of Figure 6 which permits the springs 63 to move the slide 60 forwardly, moving the rod 12 outwardly to a forward inoperative position, at which time, however, the arm 4 is prevented from following all the way by impingement of a stop 90 thereon (see Figure 8) on a fixed abutment 9| on the frame. In this position of the arm 4, the dogs 5! to 54 are held back out of operative relation to the lever 55, as shown in Figure 12a, and it is then poss ble to move the carriage 51, carrying this lever 55, ax ally to move it back or forth into alinement with the space between one pair of lugs as 33 and 5 or the other pair of lugs 5| and 52, depending upon whether grinding or wheel truing is to be effected. The reverse device carriage 51 is movable, also, to present one or the other grinding wheel into grinding or truing positions.

Beside supporting the dogs BI, 52 and 53, 54, the positions of which determine limits of traverse for truing and grinding, respectively, the bracket II) also carries a cam plate 95 having a cam face 96 sloping in accordance with the angle of the taper desired and taking in account also the angular motion of the arm 4 which slightly modifies the angle of the cam plate necessary to produce the desired taper of the work face. The cam plate 95 is adjustably secured to the bracket Ill on a pivot 950 about which it may be angularly adjusted by turning the screws 95I which engage its rear edge, after which screws 952, passing through slots in the cam plate 95 and threaded into the bracket I0, may be tightened to secure the plate 95 in adjusted position. This cam face 96 is, adapted to cooperate with either selected of a pair of follower rolls 91 or 98 journale'd on a corresponding pivot 99 and carried by the carriage 51, and controls the path of motion of each of the grinding wheels both during work grinding and during wheel truing. The two wheels are therefore controlled exactly alike, which would be very difiicult to accomplish if diiferent cams were employed. Angular adjustment of the cam plate 95 produces exactly the same effect for both Wheels, both in grinding and in truing. The roll 91 is positioned to cooperate with the slope 96 of the cam '95 during the grinding of the work, while the roll 98 is positioned to cooperate with the same cam face when the wheel is retracted from the work and is in position to be trued by the truing device shown at I09 in Figure 12, this truing being done preferably when the pilot valve is in truing angular position in accordance with the controls fully described in my patent to which reference has already been made. the speed of traverse during truing being slower than when grinding.

Means are provided, when the arm 4 is engaging the stop 9!, the disk 83 being in the dotted line position of Figure 6, so that the slide 60 is in its forward position with the mechanism carried by the carriage 51 out of cooperative relation to the devices carried at the lower end of the bracket ID, as shown in Figure 12a, for moving the carriage 51 in one or the other direction axially of the work to change from one to the other axial position corresponding to the grinding faces of the roughing and finishing grinding wheels. This mechanism is shown best in Figures 2 and 3. At opposite ends of the carriage 51 there projects therefrom a long bolt I I0, one only of these being shown in Figure 3, this bolt having its threaded end engaged in a nut III seated in a socket member I I2 suitably secured to the corresponding end of the carriage 51. The head H5 of the bolt III! is seated in a socket H6 in the outer end of a piston I I! which is slidable axially within a fluid ressure cylinder H8. The outer end of the socket I I6 may be closed off by a plug I !9 threaded thereinto. One end of the cylinder III) is closed off by a head I29 within which is screwed a pipe I2I leading into the interior of the cylinder, this pipe forming a leakage drain. The other end of the fluid-receiving portion of the cylinder H8 is closed off by a head I22 through which. the bolt H9 extends, this read I22 being secured to the end of a sleeve I23 fixed within the cylinder H8. The sleeve I23 forms a portion of a housing for the reception of a stop sleeve I24 through which the bolt IIO extends and which is externally threaded for a portion of its length as at I25. The remainder of the housing comprises the cylinder I I8 and an extensible and collapsible bellows I29 extending between and secured to a head II80 for the cylinder H8 and the socket member II 2. This threaded portion extends through a matingly threaded hub portion I26 of a worm wheel I2'I which is also provided with an oppositely extending hub I28. The hubs I26 and I28 are journaled within the cylinder member II8 as on the roller bearings I30, the inner raceways of which are held in position by nuts I 3I threaded onto the end portions of the hubs I26 and I28. The worm wheel IZ'I' has meshing therewith a worm I32. The sleeve I24 is shorter than the distance between the inner end of the cylinder head I22 and a flange extension I34 of the member II2.

On introducing fluid under pressure between the piston II! and the head I22, as through the port I35, the piston I Il may be driven to the left, thus pulling on the bolt H0 and bringing the abutment I34 against the adjacent end of the stop sleeve I24, this defining a limit of such motion in that direction. By turning the worm I32, the worm wheel I2! is correspondingly turned and this causes an axial motion of the sleeve I24 to take place, thus determining the limit of motion to the left of the carriage 51 and this may be adjusted so as to present the active face of the finish grinding wheel into proper relation to the work (see Figure 11) so that when the wheel is again placed in responsive action to the cam face 96, the reciprocation of the wheel spindle between its limits of traverse determined by the dogs 53 and 54 produces the desired grinding action of the wheel on the work, or when the roll 98 is engaged with the face 96, the moper truing action on the wheel face is produced. Feeding of the finish grinding wheel axially against the work for the grinding operation or against the truing device for the wheel truing is thus produced by turning of the worm I32 in the direction to move the sleeve I24 to the left, since this displaces the wheel axially in the Same direc tion relative to the work and to the truing device, but the direction of traverse is .parallel to the inclined grinding face of the wheel, having both axial and lateral components, as determined by the slope of the cam face 99, while the amplitude of traverse is determined by the spacing of the pair of dogs 53 and 54 for grinding and 5| and 52 for truing, respectively.

It will be understood that there is a similar mechanism to that shown in Figure 3 secured to the right hand end of the carriage 51, and by the proper adjustment of this mechanism the grinding face of the rough grinding wheel is adjusted so that it properly acts upon the work, or is trued by the truing device when the cam rolls 9'! and 98, respectively, are brought into controlled relation to the cam face 99. This adjustment is made by turning an actuating worm similar to the Worm I32 and is progressively to the left to feed and to compensate for wheel wear and truing since the active grinding face of the roughing wheel is at its left end the same as that of the finish grinding wheel, and its feed direction relative both to the work and to the truing device is therefore also to the left. Grinding wheel wear and truing thus progresses axially of both wheels toward the right and this is compensated for by adjustment of the sleeve I24 and the corresponding sleeve for the roughgr'inding wheel, to displace these wheels correspondingly to the left with reference to their traverse controlling mechanisms, the left limit of displacement of the carriage 51 being the position for the finish grinding and wheel truing and the right hand limit being the position for rough grinding and wheel truing. The dressing diamond being set at a distance from the surface to be ground equal to the distance between the centers of the rolls 9'! and 98, the settings of the stop sleeves will be the same for both grinding and dressing. Thus the carriage Si is moved to one or the other of its adjusted axial positions shown in Figures 9 and 10, or in Figure 11, by introducing fluid under pressure to either the right hand port I35a or the left hand port I35. This is accomplished under contrcl of the operator as shown diagrammaticall in Figures 13 and 14 in which the right hand cylinder Etta with its piston Illa cooperateswith the cylinder IIS and piston II! at the left hand end to control the position of the carriage 57. Fluid pressure leading to the ports I35 and I35a is controlled by the four-way valve I55.

Adjustment for the limits produced by adjustment of the stop sleeves I24 by rotation of the corresponding worm I32 may be made independently for each grinding wheel and is accomplished by micrometer mechanism shown best in Figure 4 in which the left hand mechanism for the finish grinding wheel is illustrated, it being understood, however, that the right hand mechanism for the rough grinding wheel may be identical therewith. The worm I32 is carried by a shaft I45 which is journaled in a bearing [4| carried by the gear housing I 52 of which the cylinder I! 8 is an integral part. The forward end of the shaft MI!- is splined as at 15 within a sleeve I45 secured to the interior of one end of a tube I'll. Also mounted for axial but non-rotative motion relative to the tube 47 is a cross-head I48 secured to the rear end of a shaft I49. This shaft Hi9 extends through a sleeve I55 which is journaled in a bushing II through a stationary hub member I52 having an end flange I53 seated in a recess I54 of the forward frame member E9. The forward end of the shaft I49 extends into a hub cap member I55 of a hand wheel I55 where it is secured as by a nut I57 threaded onto its reduced extremity. The sleeve I50 is keyed to the hub of the hand wheel I 56 and journaled thereon is the hub of an indexing wheel I 56. This indexing wheel has journaled therethrough adjacent to its periphery a shaft I5I having a pinion I62 thereon meshing with teeth of an external ring gear I53 secured to the back face of a ring I64 bolted to the hub of the hand wheel I55. The shaft I5I has secured thereto a knurled actuating wheel I65. B turning this hand wheel I65 the pinion I62 engaging the ring gear I63 rotates the hand wheel at a slow rate of speed. The member I55 is held against rotation. The means for so holding it comprises a lever I which can be dropped down into position to engage over a pin I1 I projecting therefrom. By lifting the lever I10 out of contact with the pin Ill, the member I59 is free to rotate and a quick adjustment may then be provided by rotating the hand whee1 I55 directly. the member I55 rotating freely therewith. When the adjustment approaches final position, a slow rotation may then be produced by locking the member I65 against rotation and thereafter rotating the knu led wheel IE5. Turning of the hand wheel I55 turns the shaft I49 and through its extensible coupling rotates the shaft I45 andthus adjusts the stop sleeve I24. This mounting of the hand wheel is thus ata fixed position, though the stop sleeve may be moved forwardly and backwardly as well as axially.

A corresponding mechanism, the elements shown being marked with the corresponding numeral with the subscript a. is shown in Figure 2 at the right, for adjusting the right hand stop sleeve for the rough grinding Wheel. Since adjustment of the right hand stop sleeve determines the position of follower roll 9? which engages the cam portion during the rough grinding, this may be employed to accomplish the wheel feed and a ratchet Il5 (see Figure 1) carried by a reciprocating bar I15 actuated by a fluid power motor II'I may be employed for this purpose. This may be of well known construction. In case onl one grinding wheel for both rough and finish grinding is to be used, the stop adjusting means for the grinding wheel not used may be omitted. This is shown in Figure 5 where the adjusting hand wheel I55 for the left hand mechanism with its associated parts has been removed and a plate I35 has been applied over the opening for the shaft I49.

It has been before pointed out that reversal of the direction of traverse is accomplished by rocking the lever 55 and that the ax al reciprocation of the pilot valve to produce such reversing of the traverse is accomplished by the fluid pressure mechanism including the cylinder I9 and piston 35 shown in Figure '7. Means by which the rocking of the reverse lever 55 controls fluid pressure applied to opposite ends of the cylinder I I8 is shown best in the diagrammatic Views Figures l3 and l i and a modified construction in Figure 15. Referring to Figures 13 and 14, the forward end 25!! of the lever 55 rides between the adjacent ends of a pair of valves 25! and 255, riding within cylinders 253 and 285, respectively. Each of these cylinders receives fluid under high pressure from the pressure line 255 into an annular port 255 and in the positions shown in Figure 12a the lever 55 is centered by them. In the position of the parts shown in Figure 13, fluid pressure from the annular port 255 in the left hand cylinder 253 passes through the valve port 25?, the valve casing port 258 and the pipe 32 into the right hand end of the cylinder I9, while the left hand end of the cylinder I5 connects through the pipe 3 i, the port 258 of the right hand cylinder 285 to the right hand end of the valve 202, forcing the plunger of this valve toward the lever end Zilikwhile pressure bleeds out from both remote ends of the cylinders 253 and 255 through the line 2i 5 to the low pressure discharge line.

When the lever 55 is thrown to the position shown in Figure 14:, the right hand valve 292 is pressed inwardly so that pressure passes through its passage 255 and the pipe 3i to the left hand side of the cylinder I9, forcing the piston 35 to the right and discharging from the right hand end of the piston 35 from the cylinder I9 through the pipe 32 and the right hand end of the valve cylinder 2% to discharge.

In Figure 15 is shown a modification in which the lever 55 itself exerts the pressure which causes the reverse motions of the piston 5E3. In place of the valves actuated by the rocking of the lever 55, its end 255 engages against one or the other of a pair of plungers 225 and .228. The plunger 225 rides in a pressure cylinder the outer end of which is connected to a low pressure fluid line 223 through a check valve 225, while a similar connection through a check valve 225 is made to the outer end of the cylinder 226 which contains the plunger 22!. Also from the outer endportions of these cylinders extend the pipes 3| and 32, respectively, to the cylinder It. The plungers 220 and 22! when in their innermost positions uncover ports leading to a discharge pipe 228, but when either of these plungers is moved outwardly, as the left hand plunger is shown in Figure 15, the corresponding discharge port is closed, and as the check valve 225 prevents reverse direction flow in the pipe 223, outward movement of the plunger 220 increases the pressure of fluid trapped between the check valve 224 and the cylinder l9, and moves the piston 30 to the left, fluid pressure escaping from the left hand end of this piston 3i! through the line 3!, and the outer end of the cylinder 226 to the discharge line 2'28. When the lever 55 is rocked in the reverse direction, the relative positions of the plungers 225i and 22! is reversed, causing pressure to build up in the pipe 31 and to be discharged from the pipe 32, thus reversing the direction of motion of the piston 30. As shown, opposite ends of the pressure cylinder I9 are connected through small bleeder lines 230 to the supply tank, this allowing a free small flow which is effective to discharge any air which might otherwise become pocketed within the cylinder I9 and interfere with smooth operation of the mechanism.

Assuming that the two wheels 59 and il, 49 for finish grinding and M for rough grinding are to be employed, the mechanism is adjusted so that the stops 53 and 5 2 are operative to effect the traverse reversal, as shown in Figures 9 and 10, and the cam 95 is in position to engage the follower 97. The machine is then started into operation and the rough grinding wheel is caused to traverse the work whilethe Wheel carrier is rocked forwardly and backwardly through the action of the cam 95 to cause the grinding face of the rough grinding wheel to traverse the work at the desired taper angle, Figures 9 and showing the parts at the outer and inner traverse limits just at the point of being reversed.

When dressing of the rough grinding wheel is desired the lever Bl is thrown down to the dotted line position of Figure 6 to retract the carriage 60 and the Wheel slide is moved toposition the roll 98 opposite to the cam 95 and the lever 8Tis lifted to position the parts as shown in Figure 12. The dressing device is advanced and the pilot valve is turned to dress position. After dressing is complete the machine is again moved to its inoperative position with the handle 81 in its dotted line position, the rough grinding wheel is removed, and the carriage 51 is moved axially to bring the active grinding face of the wheel 48' into the axial position previously occupied by the active grinding face of the roughing wheel 4|. The wheel is then returned to operative position and the lever 8'! up, with the dogs 53 and 54 incontrolling relation to the reverse lever 55 and the cam rolls 9'! in operative relation to the cam 95 in the position shown in Figure 11, the traverse then being resumed for finish grinding. Dressing of the finish grinding wheel is done similar to dressing of the rough grinding wheel while the stop dogs El. and 52 are operative but with the carriage 57 in the left hand position of Fig,-

ure 11. H 7

It will be noted that the directions of motion of the active grinding wheel portions of both wheels both for grinding the work and for truing are all controlled by a single cam so that the grinding wheel faces are maintained in accurate parallelism and move across the work face in accurate parallelism.

The truing device I00 may be moved into and out of operative position by fluid pressure means under the control of an operator-controlled handle 250 in the well understood manner.

From the foregoing description of certain embodiments of this invention it should be understood by those skilled in the art that various other changes and modifications might be made without departing from the spirit or scope of this invention.

I claim:

1. A grinding machine comprising a pair of members one movable relative to the other in traverse direction and in a direction transverse to said traverse direction, a grinding wheel spindle carried by one of said members and extending parallel to said traverse direction and having means for supporting a plurality of grinding wheels each having an active taper portion, a work holder carried by the other member, power means for relatively traversing said members, cam means for causing the traverse to produce said relative transverse motion, said power means including a direction reversing mechanism having an actuating lever carried by one of said members and a pair of spaced dogs carried by the other of said members in position to swing said lever at the traverse limits and thereby reverse the traverse direction, and means actuable to relatively move said lever and dogs and a portion of said cam means between positions in one of which the active portion of one of said wheels may operate upon work held by said work holder and in the other of which positions the active portion of the other of said wheels may operate on the work.

2. A grinding machine comprising a pair of members one movable relative to the other in traverse direction and in a direction transverse to said traverse direction, a grinding wheel spindle carried by one of said members and extending parallel to said traverse direction and having means for supporting a plurality of grinding wheels each having an active taper portion, a work holder carried by the other member, power means for relatively traversing said members, cam means for causing the traverse to produce said relative transverse motion, said power means including a direction reversing mechanism having an actuating lever carried by one of said members and a pair of spaced dogs carried by the other of said members in position to swing said lever at the traverse limits and thereby reverse the traverse direction, means actuable to relatively move said lever and dogs and a portion of said cam means between positions in one of which the active portion of one of said wheels may operate upon work held by said work holder and in the other of which positions the active portion of the other of said wheels may operate on the work, and operator-actuable means for controlling said last mentioned means.

3. A grinding machine comprising a work holder and a grinding wheel spindle mounted for traverse parallel to said spindle and for motion transverse to the line of traverse, said spindle having means for supporting a pair of grinding wheels in different axial positions therealong, each of said wheels having a tapered peripheral portion, power means for traversing said wheel spindle including a direction reversing mechanism having an actuating lever and spaced dogs movable with said wheel spindle in position to contact and move said lever at traverse limits and reverse the direction of traverse, means causing such power traverse to efiect such transverse motion to produce motion of said wheel spindle parallel to the taper of said wheels and means for moving said lever in traverse direction parallel to said spindle between a pair of positions in one of which the tapered portion of one of said wheels is in position to traverse the work and in the other of which the tapered portion of the other of said wheels is in position to traverse the work.

4. A grinding machine having members comprising a work holder and a grinding wheel support, a grinding wheel spindle carried by said support, power means for producing relative traverse between said members, controlling means for said power means including an element movable parallel to the line of traverse for reversing the direction of traverse by such movement, a movable part carried by one of said members, spaced dogs between which said part moves as said members are relatively traversed in position to engage and move said part adjacent to opposite traverse limits, power means controlled by su:h motion of said part and connected to said element for moving said element to reverse the direction of traverse, a part carrying said spaced dogs, and means for adjusting said parts relatively and relative to one of said members to adjust the zone of traverse relative to said one member.

5. A grinding machine having members comprising a work holder and a grinding wheel support, a grinding wheel spindle carried by said support, power means for producing relative traverse between said members, controlling means for said power means including an element movable parallel to the line of traverse for reversing the direction of traverse by such movement, a movable partcarried by one of said members, spaced dogs between which said part moves as said members are relatively traversed in position to engage and move said part adjacent to opposite traverse limits, power means controlled by such motion of said part and connected to said element for moving said element to reverse the direction of traverse, operative connections between said part and element causing motion of said part to cause traverse reversing motions of said element, a part carrying said spaced dogs, means for adjusting said parts relatively to change the traverse zone from one to a different definite position, and means for adjustably determining such definite positions.

6. A grinding machine having members comprising a work holder and a grinding wheel support, a grinding wheel spindle carried by said support, power means for producing relative traverse between said members, controlling means for said power means including an elementmovable parallel to the line of traverse for reversing the direction of traverse by such movement, a movable part carried by one of said members, spaced dogs between which said part moves as said members are relatively traversed in position to engage and move said part adjacent to opposite traverse limits, power means controlled by such motion of said part and connected to said element for moving said element to reverse the direction of traverse, operative connections between said part and element causing motion of said part to cause traverse reversing motions of said element, power means for changing the traverse limits each from 12 one to adifierent position, and operator-actuable means for controlling said power means.

7. In combination, a work holder, a grinding wheel support, a grinding wheel spindle journaled on said support parallel to the axis of work on said work holder, a grinding wheel on said spindle, said support being biasedto bring said grinding wheel toward said axis, means for moving said support parallel to said axis to cause relative traverse between the wheel and work, elements comprising a cam and followers for said cam, one of said elements being carried by said support and the other of said elements being normally fixed, means actuable to withdraw said normall fixed element to an inoperative position, means for limiting the motion of said support toward said axis to a position where said elements are out of contact when said normally fixed element is in inoperative position, and means effective when said normally fixed element is in inoperative position to move said support to select WhlCh of said followers shall be in operative relation to said cam when said normally fixed element is returned to operative position.

8. In combination, a. work holder, a grinding wheel support, a grinding wheel spindle journaled on said support parallel to the axis of work car ried by said work holder, a grinding wheel on said spindle, said support being biased to bring said grinding wheel toward said axis, means for moving said support parallel to said axis to cause relative traverse between the wheel and work, a pair of devices comprising a traverse reversing means and a plurality of sets of traverse limit dogs, one of said devices being carried by said support and the other device being normally stationary in cooperative relation to said one device, means efiective to withdraw said other device from cooperative relation to said one device, means limiting motion of said support to prevent equal motion of said one device as said other device is moved out of cooperating position, and means effective while said other device is so withdrawn to move said other device transverse to its withdrawal direction to select a different set of limit dogs in position to control said traverse reversing means when said other device has been thereafter returned to cooperative position.

9. In combination, a work holder, a grinding wheel support, a grinding wheel spindle journaled on said support parallel to the axis of work on said work holder, a grinding wheel on said spindle, said support being biased to bring said grinding wheel toward said axis, means for moving said supportparallel to said axis to cause relative traverse between the wheel and Work, elements comprising a cam and followers for said cam, one of said elements being carried by said support and the other of said elements being normally fixed, means actuable to withdraw said' normally fixed element to an inoperative position, means for limiting the motion of said support toward said axis to a position where said elements are out of contact when said normally fixed element is in inoperative position, devices comprising a traverse reversing means and a plurality of sets of traverse limit dogs, one of said devices being carried by said support and the other device being movable with said normally fixed element into and out of cooperative relation to the other of said devices, and means operative when said normally fixed element and said other device are out of cooperative relation to the other element and said one device, respectively, to move said devices and ele ments relatively to present any selected into controlling relation on return of said normally fixed element and other device into cooperative positraverse limit dogs carried by one of said members adapted to contact and move an actuating element on the other of said members adjacent to opposite limits of traverse, a fluid pressure motor system for moving said movable element including a fluid pressure motor connected to said movable element, a pair of fluid pressure supply pipes for said motor, check valves in said pipes preventing back flow, a pair of cylinders in said system between said check valves and said motor, plungers in said cylinders, said cylinders having discharge ports each communicating with its respective'pipe when its plunger is in one position, said actuating element being positioned between to move one or the other of said plungers to close its discharge port and build up pressure in the corresponding pipe between its check valve and said motor while the other pipe is open to discharge, to thereby actuate said motor and move said movable element to cause reversal of the direction of traverse.

11. In combination, members comprising a work holder and a tool support, means for effecting relative traverse between said holder and support, means for reversing the traverse direction including devices one comprising a pair of spaced opposed traverse limit dogs carried by one of said members, and another device comprising a movable element carried by the other of said members for contact and movement by said dogs, one of said devices being movably carried by its carrying member in the direction of traverse to vary both traversing limits, and means for so moving said device.

12. In combination, members comprising a work holder and a tool support, means for effecting relative traverse between said holder and support, means for reversing the traverse direction including devices one comprising a pair of spaced opposed traverse limit dogs carried by one of said members, and another device comprising a movable element carried by the other of said members for contact and movement by said dogs, one of said devices being movably carried by its carrying member in the direction of traverse to vary both traversing limits, power means for so moving said device, and operator-actuable means for controlling said power means.

13. In combination, members comprising a work holder and a tool support, means for effecting relative traverse between said holder and support, means for reversing the traverse direction including devices one comprising a pair of spaced opposed traverse limit dogs carried by one of said members, and another device comprising a movable element carried by the other of said members for contact and movement by said dogs, one of said devices being movably car-' ried by its carrying member in the direction of traverse to vary both traversing limits, means for so moving said device, and means for adjustably limiting the extent of motion of said movable device.

14. In combination, members comprising a work holder and a tool support, means ior effecting relative traverse between said holder and support, means for reversing the traverse direction including devices one comprising a pair of spaced opposed traverse limit dogs carried by one of said members, and another device comprising a movable element carried by the other of said members for contact and movement by said dogs, one of said devices being movably carried by its carrying member in the direction of traverse to vary both traversing limits, means for so moving said device, and means for adjustably limiting the extent of motion of said movable device comprising a movable stop and a micrometer means for adjusting said stop.

15. In combination, members comprising a work holder and a tool support, means for effecting relative traverse between said holder and support, means for reversing the traverse direction including devices comprising spaced traverse limit dogs carried by one of said members, and

a movable element carried'by the other of said members for contact and movement by said dogs, one of said devices being movably carried by its carrying member in the direction of traverse to vary the traversing limits, means for so moving said device, and means for moving one of said devices transverse to the direction of traverse into and out of cooperative relation to the other of said devices.

16. In combination, a pair of members comprising a work holder and a tool support, means for moving said support to produce relative traverse between a tool on said tool support and Work on said work holder, means for reversing the direction of traverse including devices comprising spaced traverse limiting dogs carried by one of said members and a movable element carried by the other member for contact and movement by said dogs during such traverse, the device carried by said work holder being movable in the direction of traverse to vary the traverse limits and transverse to the traversing direction to move into and out of cooperative relation to the other of said devices, stop means adjustable in traverse direction and movable with said movable device transverse to traverse direction to determine the limits of adjustment of said traverse limits, and means supported in fixed position actuable to adjust said stop means.

1'7. In combination, a work holder, a grinding wheel carriage, means for effecting relative traverse between said carriage and work holder, a plurality of grinding wheels carried by said carriage in different positions lengthwise of said traverse for selective operation on work on said work holder, a cam and follower mechanisms for said cam relatively movable with the relative motion of said carriage and work holder and determining the relative positions of said holder and carriage transverse to said traverse, and means for changing the relation between said cam and said follower mechanisms in accordance with the particular wheel selected to cause the active face of the selected wheel to have a motion relative to the work determined by said cam as said holder and carriage are relatively traversed.

18. In combination, a work holder, a grinding wheel carriage, means for efiecting relative traverse between said carriage and work holder, a plurality of grinding wheels carried by said carriage in different positions lengthwise of said traverse for selective operation on work on said work holder, a wheel truing device relative to which either selected wheel may be moved to be trued thereby, a cam and follower mechanisms for said cam relatively movable with the relative motion of said carriage and work holder and determining the relative positions of said holder and carriage transverse to said traverse, and means for changing the relation between said cam and said follower mechanisms in accordance with the particular wheel selected and in accordance with whether work grinding or wheel truing is desired to cause the active face of the selected wheel to have a motion relative to the work when grinding is to be effected and relative to said truing device when wheel truing is to be effected determined by said cam as said holder and carriage are relatively traversed.

19. In combination, a work holder, a grinding wheel carriage, means for effecting relative traverse between said carriage and work holder, a plurality of grinding wheels carried by said carriage in different positions lengthwise of said traverse for selective operation on work on said work holder, a cam and follower mechanisms for said cam relatively movable with the relative motion of said carriage and work holder and determining the relative positions of said holder and carriage transverse to said traverse, means for changing the relation between said cam and said follower mechanisms in accordance with the particular wheel selected to cause the active face of the selected wheel to have a motion relative to the work determined by said cam as said holder and carriage are relatively traversed, and means for adjusting the position of said cam.

20. A grinding machine comprising a pair of members one movable relative to the other in traverse direction and in a direction transverse to said traverse direction, a grinding wheel spindle carried by one of said members andextending 16 parallel to .said'traverse. direction and having means for supporting a plurality of grinding wheels each having an active taper portion, a work holder carried by the other member, power means for relatively traversing said members, cam means for causing the traverse to produce such relative transverse motion, said power means includinga direction reversing mechanism having an element carried by one of said members and a pair of spaced dogs carried by the other of said members-in position to actuate said element at the traverse limits and thereby reverse the traverse direction, and means actuable to relatively move said element and dogs and a portion of said cam means between positions in one of which the active portion of one of said wheels may operate upon work held by said work holder and in the other of which positions the active portion of the other of said Wheels may operate on the work,

MERTON H. ARMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,300,481 Arms Nov. 3, 1942 983,975 Bryant Feb. 14, 1911 1,817,953 Stevens Aug. 11, 1931 1,826,178 Kempton et al. Oct. 6, 1931 1,949,552 Taylor et a1 Mar. 6, 1934 1,300,923 Bryant Apr. 15, 1919 1,779,094 Heald et a1 Oct. 21, 1930 2,139,896 Johnson Dec. 13, 1938

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