US1805056A - Grinding machine - Google Patents

Description

MayAlZ, 1931. E. M. TAYLOR GRINDING MACHINE Filed Sept.

17, 1927 sheets-Sheet 1 w m55 mbUdm l gnvenoz Edwad, (V) Tcl May l2, 1931. E. M` TAYLOR GRINDING MACHINE Filed Sept. 17, 1927 6 Sheets-Sheet 2 May 12, 1931. E. M, TAYLOR GRINDING MACHINE Filed sept.

17, 1927 6 Sheets-Sheet 5 gnuwykoz dward (VlTlHor 6 Sheets-Sheet 4 Filed Sept. 17, 1927 SH01 nu' May 12,1931. E. M. TAYLOR 1,805,056

GRINDING MACHINE Filed Sept. 17, 1927 6 Sheets-Sheet 5 13 Elim@ m. Taeor,

May 12, 1931. E. MA TAYLQR 1,305,056

GRINDING MACINE Patented May i2, 193i 1,05,056

UITED STATES PATENT. CFFICE EDWARD M. TAYLOR, F WORCESTER, MASSACHUSETTS, ASSIGNOR TO TEE HEALD MA- I CHINE COMPANY, 0F WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSA- GHUSETTS GRINDING MACHINE Application filed. September 17, 1927. Serial No. 220,248.

The invention relates to grinding magrinding wheel or the work 4to bring one chines, and particularly to automatic into engagement with the other can be at grinding machines in which the grinding the same high speed. operation'automatically terminates or ceases rlhus a grinding machine of the character 5 when the workpiece has been brought to a set forth should have instrumentalities for 5 predetermined size.. More especially, the causing the table or carriage which carries invention relates to grinding machines proeither the grinding wheel or work holding viding automatic means for separating the chuck, to'be capable of at least four changes work and wheel for a dressing operation in of speed in the cycle of operations on each advance of attainment by/ the workpiece of workpiece. Such a grinding machine is e() the aforesaid predetermined size. A grindillustrated in a copending application Serial ing machine of the above character has great No. 25,900, of Heald and Guild, filed April utility when employed to grind the internal 25, 1925 U. S. Letters Patent No. 1,779,094, surfaces of small articles, such as gears, bushgranted Oct. 2l, 1930. The present invenings, ball races and the like, and it is in contion is,in one of its aspects an improvement nection with such a machine that the present on the grinding machine shown in this apinvention is illustrated and described. -plication, in that it provides improved means A machine of the above character profor controlling the flow of pressure fluid vides means for causing a traversing movewhich gives the wheel or work holding carment between the grinding wheel and the riage its motions at different speeds. But In workpieces, means to. extend or amplify this it is to be understood that the present inventraverse in order to cause the grinding wheel tion is not limitedy to use in a grinding mato move past a dressing instrumentality. folchine as above set forth, for the speed conlowed by a resumption of the normal tra trolling instrumentalitiescould be used, for

verse. to finish the grinding operation, and, example, in a grinding machine which profinally, means to cause a. final substantial vides no dressing instrumentalities, but in separation of the wheel and workpiece in which it is sometimes desirable to slow down order that the finished workpiece may be the speed of traverse at the final stage of removed from the machine and an unground grinding, as determined, for instance, by

one substituted in its place in the work holdthe reduction of the rate of cross or transso ing chuck. Such a machine is shown in the versel feed that causes the grinding wheel co-pending application Serial No. 4466, of to progressively cut deeper and deeper into Heald, Guild, Burns and Garno, filedJanu the workpiece.- e ary 24, 1925 U. S. Letters Patent No. 1,7 51,- In another aspect the present invention is 202, granted March 18, 1930. j an improvement upon the machine shown in a3 During the dressing of the grinding wheel, my own copending application Serial No. as above outlined, it is desirable that the rela- 83,592, filed January 25. 1926, now Patent tive motion between the grinding wheel and No. 1,682,673, granted August 28, 1928, in the dressing instrumentality be at a slow rate that it is shown applied to a machine having f 40 of speed, in .order that grooves may not be the instrumentalities therein disclosed. cut in the surface of the wheel. lDuring the Briefly, my former invention contemplated final and finishing cuts on the workpiece, it the dressing of the grinding wheel in reis desirable that the speed of traverse be sponse to an electric circuit closed by action slower than it is during the preliminary or of the transverse feeding instrumentalities,

roughing cuts, but it need not be so slow yand a subsequent known advance of the said JL as it is during the dressing operation. On transverse feed to bring the work to the finthe other hand, the final movement of withished size, automatic compensating instru-4 .drawal 'can/be,l and desirably should be, at mentalities being provided to insure contact the greatest speed of which the machine is .between thel wheel and the dressing point,

5 0 capable, and the initial movement of` the despite the ordinary wear due to the grind- 101` ing operation, and the reduction of the wheel due to the previous dressing. In this particular aspect of the present invention, improvements in the automatic electric switching mechanism are involved.

The present invention also involves the elimination of certain mechanical table controlling instrumentalities that were shown in the Heald, Guild, Burns and Garno application, and speed control instrumentalities shown in the Heald and Guild application, and the substitution of simpler instrumentalities; this improvement being madel possible by reason of the novel valve employed, which obviates the necessity of controlling lthe How of fluid at the different stages of the grinding operation directly from the motion of the table, or from the action of the dressing mechanism in bringing the dresser point into position. According to the present invention, a single control device performs these functions, with the consequent elimination of many parts from the grinding machine carriage dresser-moving instrumentalities.

The invention further consists in the novel valve device per se, and in certain combinations of parts and motions, all of which will more fully appear in the following detailed description, taken in connection with the accompanying drawings, in which- .f

Fig. Al is a front elevation ofa grinding mac ine constructed in accordance with the invention. t

Fig. 2 is anisometric view of the automatically actuated valve mechanism' that determines the speed of travel of the machine carriage, together with the actirating mechanism therefor and the electric switch mechanism which is incorporated with it.

Fig. 3 is,` a diagrammatic showing, iniisometric form, of the various fluid pressure actuated mechanisms and the fluid pressure connections between them, without relation to the actual positions of the parts inthe machine.

Fig. 4 is a vertical sectional view of a certain Fig. 2.

Fig. 5 is a vertical sectional view of another portion of the mechanism shown in Fig. 2, being taken on the axis of the shaft that actuates the speed control valve and the switch mechanism.

Fig. 6 is a horizontal sectional view', taken on the line -6--6 of Fig. 5.

Fig. 7 is a plan view of they escapement mechanism shown in Fig. 2 that controls the movement of the valveand switch mechanism. f

Fig. 8 is a front elevation of the 'escapement pawls shown in Fig. 7.

Fig. 9 is an isometric view of the grinding machine carriage controlling and reversing mechanism.

and a simplification of thev portion of the mechanism shown in h `mechanism employed, the fluid 8 is located in the Fig. 10 is a vertical sectional view of the carriage speed controlling valve.

Fig. l1 is a horizontal sectional view, taken on the line 1l 11 of Fig. 10. f

Fig. 12 is a vertical sectional view of the reversing valve for the grinding machine ycarriage, together with associated mechamsm.

Fig. 13 is a wiring diagram.

Fig. 14 is a piping diagram in plan view, showing the parts in substantially the position they occupy in the machine.

Like reference characters refer to like parts Lin the different figures.

Referring first to Fig. 1, an internal grinding machine is shown having a reciprocatory table or carriage l, such as is ordinarily provided in any internal grinding machine. In .such a machine, either the grinding Wheel or the work to be ground may be carried on the table 1, the reciprocation of the latter being utilized in either case to produce a relative traversing movement between the grinding wheel and the work. As here shown, the table 1 supports and carriesl a wheel head 2, while the work which is to be operated upon is held in a work head 3, the latter ,being carried by a bridge 4, which spans the slideways provided by the machine frame for the back and forth movement of the table 1.`

The grinding wheel 5 is carried on a spindle 6 which is suitably journalled in the wheel head 2, and any suitable means, which need not herein be described, is provided to rotatesaid spindle 6 and wheel 5. The workpiece holding chuck, which is located inside the water guard 7, is also rotated, but desirablv at a slower speed.

The reciprocation of the table 1 to cause the rotating grinding wheel to make the required interior traverse of the rotating workpiece isimparted bymeans of fluid pressure controlling and reversing mechanism, desirably of the type described in United States Letters Patent No. 1,582,468, to Heald and Guild, granted April 27, 1926. Irrespective, owever, of the exact type of reversing pressure mechanism procures the reversal of the table l at each end of the latters normal working stroke by the use of spaced adjustable dogs 8 and 9, carried by the table 1 andadapted to alternately engage and move a reversing member 10. The latter, as clearly shown'in Figs. 1 and 9, provides two upwardly extendlng portions 11 and 12 which are preferably of the same height, but are located in different vertical planes. The left hand table dog plane of the right hand ight hand table dog 9 is' inv the plane of the portion 12; during the grinding operation, when the wheel 5 is moving back and forth -within the workpiece, both portions 11 and 12 of the reversing portion 11, and the v work-piece.

member 10 are situated adjacent the dogs 8 and 9 in position to be struck alternately by said dogs, and said member 10, by its consequent movements first in one` way and then the other, effects the reversals in the travel of the table 1.

The reason for providing spaced portions 11 and 12 in different planes on the reversing member 10, instead of merely forming it with a single upwardly extending portion, as shown in the prior applications referred to, is to produce in the table 1 a traverse of very limited range, if desired. rFhe traverse must always be great enough to move the reversing valve far enough to change the direction of flow of the iiuid, but a greater motion of the member 10, in response to a given movement of the table 1, is produced when the table dogs strike a part of the reversing member that is measurably from the centerline. This type of reversing member, however, is known to the artand need not be further described.

As already stated, the automatic operation of the machine is controlled from the` transverse feeding instrumentalities that feed the grinding wheel 5 in relation to the Thesev instrumentalities derive their motion from the motion of the table 1. As shown in Fig. 1, a cam member 13 is adjustably fastened to a long bar 14 which in turn is ancho-red at one end 4toa stationary part of the machine, such as the bridge 4, the other end of said bar being a floating end, but a roller 15 being provided by the table 1 to supportthis bar in any position of the table. The cam 13 is so positioned longitudinally of the bar 14 that a roller 16, carried by an arm 17 which is pivotally mounted at 18 to a standard 19 extending upwardly from the table 1, engages said cam at the end of each inward stroke of the table 1. This results in an oscillation of the arm 17 for every stroke of the table, and such oscillatio-ns cause a pivotally mounted pawl 2O to engage and move a ratchet gear 21. By a system of gearing fully described in my aforesaid copending application, which it is not necessary to describe herein, sinceitforms no part of the present invention, movement of said ratchet wheel 21 is transmitted to a screw shaft 22.

The wheel head 2 is carried on a cross slide which is mounted to travel on ways provided by the table 1,{the line of movement of the cross slide being at right angles to the line of movement of the table 1. The screw shaft is j ournalled in bearings carried by the standard 19 that is attached to the table 1, and the screw shaft engages a nut fastened to the said cross slide, so that angular movement of the screw shaft results in a feeding movement of the slide; this construction, being very old in grinding machines, is not herein and any variations of the same or reoffset illustrated i versals of parts thereof can be employed without departing from the spirit of the present invention.

Connected to the ratchet wheel 21 is a hand wheel 23, a fragment lof which is shown in Fig. 1, and by turning the ratchet wheel, the cross slide can be moved forward or backward by hand. 1n this connection, it should be noted that the pawl 20 engages .the 'ratchet wheel 21 only when it is4 actuated, as itis spring pressed outwardly, and is caused to move into engagement with the ratchet wheel by means of an adjustable cam device 24; from which it follows that the hand wheel can be freely turned at all times except when the roller 16 is in actual engagement with the cam 13. A

Adjustably fastened to the hand wheel 23 or the ratchet wheel 21 is a cam member 25 which therefore moves angularly wheneverl these parts move. During the normal automatic operation of the machine, the cam member 25 successively engages an adjustable screw 26 carried by a lever 27 and a similar adjustable screw 28 carried by a lever 29. `Rocking movement of the lever 27 is adapted to cause the normal working stroke of the table 1 to be amplified and to coincidentally bring a dressing device .into position in the path of the extended movement of the grinding wheel. lever 29 is adapted to cause a final movement of thetable 1 to separate the grinding wheel and the work head 3, the table being brought to a stop in the position shown in Fig. 1.

Referring to Fig. 13, the lever 27 carries a Contact 30 which, when said lever is moved, engages a stationary contact 31, and the lever 29 carries a contact 32 which will similarly engage a stationary contact 33. The successive engagement of these pairs of contacts brings about the dressing-operation and the final movement of separation aforesaid; the electromagnetic means and the mechanical means actuated thereby that causes such will be hereinafter described.

Referring now to Figs., 3, 12 .and 14, so much of the reversing valve mechanism has beenshown as is necessary -to the understand- Fig. 14, fluid under pressure may be supplied from a pump 34 incorporated into the machine, or it may be supplied from any other suitable source. At. all events, the fluid pressure supply line is indicated at 35'in the piping diagram of Fig. 14 and the diagrammatic view of Fig. 3, said supplyv line having a branch 36 that leads the fluid to the valve, generally indicated by the numeral 37, which controls the speed of flow of the fluid and thereby the speed of travel of the table 1. From the valve casing 37, piping 38 takes the pressure fluid to the reversing valve casing 39, which is shown in the sectional view of Fig. 12. As shown in said figure, the fluid is admitted by way of a port 40 to a chamber in which is located a piston 43, whose piston rod 430; is connected to the table 1. Ports 44 and 45 in the chamber connect by piping 46 and 47 to the opposite ends of the cylinder 42 and a reversing valve 48 directs the fluid by way of one or the other of said ports, the exhaust .fluid escaping by way of the port 49. It will be understood of course that thereversing Valve 48 is connected to the reversing member 10 so as to be actuated by it the mode of this connection and the exact construction of the reversing valve 48, forming no part of the present invention, need not herein be described, particularly as it is shown in United States Letters Patent No. 1,582,468 granted April 27, 1926, to Heald and Guild. A

Between the port 44 and the piping 46 is a valve 50 which is pressed downwardly towards its seat by means of a spring 51, but prevented from engaging said seat by reason of a slidable member 52" which engages a portion 53 projecting downwardly from said valve. With the parts in the position shown in Fig. 12, the fluid is `flowing through the port 44 and past the valve 50, andconsequcntly moving the table 1 to the right as the piping 46 connects to the left hand end of the cylinder. (In this connection it should be noted that the cylinder 42 is seen from the rear in Fig. 3, and the left hand end therefore appears to be the right hand end.) When the table has moved to the right on its final stroke, having carried the grinding wheel well Iaway from the workpiece, a pin 54a or other projection carried by the table on the underside thereof engages the top of a lever 54 and moves said lever in a clockwise direction. See Fig. 1 which shows the lever 54 having been moved. The action of the pin and lever is the same as that described in somewhat more detail in the patent to Heald and Guild, No. 1,582,468. According to the present invention, the lever 54 is connectedV to the sliding member 52 so that when the lever 54 is actuated by the final movement of the table 1, theslifding member is drawn to the left from the position shown in Fig. 12 to the position shown in Fig. 1. Thereupon a notch 55, provided in 4the surface of the sliding member, comes under the downwardly projecting portion 53 and allows the valve 50 to seat, which it does under. the influence of the spring 51, and this action, as it` stops the flow of fluid to the left hand end of the cylinder 42, stops the table. When, subsequently, after a new workpiece has been'placed in the chuck provided by the workhead 3, the operator of the machine wishes to cause the table 1 to travel to the left to commence the grinding operation on this fresh workpiece, he swings a lever 56 provided on the front of the machine frame,

which lever is directly connected to the reversing Valve 48 yand swings it in the same angular direction. This action admits fluid under pressure to the right hand side of the cylinder and causes the table 1 to travel to the left Fig. 1, and the fluid can exhaust from the left hand end of the cylinder by reason of the fact that the valve can always be lifted by pressure applied underneath it. Once, however, the stop, not shown, carried by the table 1 has moved away from engagement with the vlever 54, the latter swings back to the position shown in Fig. 12, carrying the slidable member 52 with it, these parts moving under the influence of a spring 57.

The movement of the sliding member 52, which as just described, occurs at the end and at the beginning of each separate grinding operation, is made use of to actuate the valve in the valve casing and also the electric switch or distributor mechanism that is associated with it. To that end the slidable member prod vor the other of two ports 61 and 62, depending on the position of the slide valve. In the position of parts illustrated in Fig. 12, which, as it will be remembered, is the normal position during the grinding operation, the reduced portion 58 connects the shunt passage 60 to the port 61 which carries the-pressure fluid by way of piping 63 to the front of a cylinder 64 carried adjacent the valve casing 37 The opposite or rear end of said cylinder is conn e( ted by piping 65 to the port 62, and in the position of parts aforesaid, fluid can exhaust from port 62 by way of the reduced portion 59 to an exhaust port 66. A second exhaust 4port 67 is located on the other side of the port 61, and as the location of these four ports 61, 62, 66 and 67 is a symmetrical one, it follows that the port 67 is covered up when the slide valve is in the position shown in Fig. 12, as is clearly shown in said figure, while movement of the valve 52 to the left at the end of a grinding operation connects this port to the port 61 and covers up port 66` f the fluid then being adniitted to the rear of 'vides a depending pin 71 fitting in a hole in a member 72 on the end o f which is cut asegment of aspur gear. See Fig. 4. The

member 72 is pivotally mounted on the casing 37 'at 73, and its gear teeth engage the teeth of a spur gear 74 which is fastened to a shaft 75. The cylinder 64 is pivotally mounted at is carried by an arm 76 to the casing 37, so that the piston rod 69 can move in a slight arc.

During the grinding operation on a workpiece and in fact at all times after the operator moves the lever 56 to the left to cause the grinding operation to be commenced, the shunt passage 60, that connects to the source of fluid under pressure, is connected by way of the port 61 and the piping 63 to the front end of the cylinder 64 and therefore is pulling on the piston 68 to tend to move the segment member 72 in a clockwise direction. This, of course, acts to tend to turn the gear 7 1 in a counterclockwise direction. But normally, except at certain intervalswhen an escapement mechanism that will be described is actuated, the gear 74 and the shaft 75 to which it is (attached, cannot be moved, being held stationary by means of a pawl 77 which is part of said escapement and which engages with a ratchet 78 also fastened to the shaft 75. When, however, the pressure fluid is made active against the rear'of the cylinder 611, by reason of movement of the slide valve -member 52 as described, the gear segment` member 72 is moved, rotating with it the gear 7 4 and the shaft 75, because there is nothing to prevent clockwise movement of the ratchet gear 78.

Referring to Figs. 1 and9', the left hand table dog 8 is carried by a block 79which, the same as the carrying block 80 of the dog 9 and the carrying block 81 of a dog 82 provided to reverse the travel of the table or J lcarriage 1 at the end of its amplified dressing stroke, is adjustably secured to the table 1 by means of any suitable adjusting and holding devices, such for instance as the hand screw nuts 83, 83, 83 applied to all three blocks and engaging with a screw rack 8/1 carried bythe table 1. The left hand normal reversing dog 8, however, and also the dog 82, instead of being fixed dogs, unmovable in relation to their holding blocks, as is the case with the right hand table dog 9, are pivotally mounted dogs, being pivotally secured to their respective carrying blocks 79 and 81 by means of pins 85 and 86, the striking ends of said dogs 82, 82` hanging downwardly by gravity and being held from further movement by the engagement of the upper parts of said dogs with the tops of guiding slots 87 and 88 in the blocks 79 and The block 79, besides carrying tbe reversing member 8, carries a cam member 89that actuates the escapement mechanism referred to. As shown in the aforesaid figures, and

also in Fig. 2, the cam member 89 is adapted to engage and depress a roller 90 which lies in its path, whenever the motion of the table 1 carries the cam past the roller. Said roller 91 mounted on a shaft the front of thefnia- 92 which projects from chine frame, the arm 91 being mounted free .counterclockwise sitions it assumes by on said shaft, but .normally connected to it by means of a pull pin 93 carried by a short arm 94 which is keyed. to the shaft, the foregoing simply constituting a ready means for breaking the connection between the arm 91 and the shaft 92 in order to manually move the valve and switch mechanism, if desired. At all events, counterclockwise movement of the shaft 92, however produced, results in actuation of the escapement mechanism to allow the shaft 75 to be turned by the fiuid pressure device, shown herein as a piston and cylinder, a definite angular amount.

' Referring now to Figs. 2,7 and 8, the shaft 92 has fastened thereto, inside the machine frame, a depending arm 95 that is connected, by means of a link 96, to a member 97, one end of which constitutes the pawl 77, heretofore referred to. The member 97 is pivotally mounted on a stud 98 extending upwardly from the casing 37, and is normally pressed to cause the pawl portion 77 to engage the ratchet wheel 78 by means of a spring 99, which fits on a holding pin 100 carried bythe casing 37, and is held in position in relation to the member 97 by means of a similar pin 101. Counterclockwise movement of the member 97 in response to actuation by the cam member 89 and the connecting mechanism just described, releases the ratchet wheel 78 so far as is concerned, but the ratchet wheel 78 is prevented from moving a greater distance than the space between teeth by a second pawl 102 carried by a member 103, which is pivotally mounted on the same stud 98 that carries the member 97. rounding the stud 98 and the hubs of the members 97 and 103 urges the member 103 in a direction, but until the member 97 moves, the member 103 cannot, by reason of the fact that they are kept separated a fixed angular distance by means, for example, of a short arm 103@ fastened to the member 103 and engaging the side of the member 97. The above, of course,'sim'ply constitutes an escapement by means of which the shaft 75 is allowed to rotate a given vangular distance when, and only when, the cam member 89 carried by the table 1 engages the roller 90.

Referring now to Figs. 5 and 6, the shaft 75 has secured thereto in any suitable manner a member 105, to which is attached a second member 106 by means of screws 107, 107. One or the other of these two members 105 and 106 is made of insulating material, and the second member is slightly movable with respect to the first, and is pressed outwardly by means of springs 108, 108 surrounding the screws 107 107. To the member 106 is fastened, as by means of screws 109, 109, a contact member 110 which, in the different po reason of the intermittent rotation of the shaft 75, is adapted to the pawl 77 countercloekwise direction.

bridge the gap between terminals 111 and 112, or 113 and 114, or 115 and 116, located in a casing 117. In this manner the automatic inauguration, first of the.k dressing stroke of the table 1, and subsequently of the final movement of withdrawal of said table, which occurs at the end of a grinding operation, when the workpiece has been brought t'o the desired size, is controlled.

Attached to the shaft 75, at a position below the contact member 110, is a rotatable member 118 located inthe valve casing 37,

but before describing this valve, the various operations in a complete cycle 'of the grinding operation of the machine will be described, so that the purpose and function of this valve maybe made clear.

The operator linds the grinding machine with its parts in the position shown in Fig. l, which position may automatically assume at the end of each grinding operation. At this time, the contact member 110 is in the position shown in dotted lines in the wiring diagram of Fig. 13, by reason of the fact that the slidable valve member 52 is in its left hand position (Fig. 12) and fluid pressure is admitted to the rear of the cylinder 64, which has caused the shaft 75 to be turned to its eXtreme clockwise position and holds it there. The operator, having placed an unground workpiece in the chuck, turned the hand wheel 23 back so that the grinding wheel can enter the hole in the workpiece, and properly set all adjustable parts of the machine, moves the hand lever 56 to the left, which action moves the reversing valve 48 in a corresponding direction, and swings the reversing member 10 to the right. The table 1 immediately moves to the left for the reasons already set forth, and this action releases the lever 54 and allows the sliding valve member 52 to move to the right under the influence of the spring 57. rlhereupon the fluid pressure is -Inadeactive at the front end of the cylinder 64, tending to move the segment member 72 to the right and consequently the gear 74 and the shaft 75 in a But none of these parts immediately move, for the reason that the pawlf`77 is engaging the ratchet wheel 78.

As the table 1 moves to the left, first the pivotally mounted dog 82, and subsequently the pivotally mounted dog 8 lift over the portion 11 of the reversing member 10 without effect on said reversingmember; at some time intermediate these occurrences, the cam member 89 comes into contact with the roller 90 and depresses it momentarily. This action causes theescapement mechanism, that has into contact with the terminals 111 and 112 in the casing 117 so that the electric connections are in the condition shown in the wiring diagram of F ig. 13 in full lines. The machine proceeds to grind the workpiece in the usual manner, the travel of the table 1 being reversed at each end of its normal stroke by the dogs 8 and 9 acting on the portions 11 and 12 of the reversing member l0. When, however, the grinding operation has proceeded far enough so that the cam 25, carried by the hand wheel 23, has been ymoved by the automatic feeding occasioned by the cam 13 and roller 14 to engage the screw 27, the dressing operation takes place/in the following manner.

As shown in the wiring diagram of Fig. 13, electric current is supplied from a generator G, or any other suitable source, and proceeds by wayof a branching lead 119 to an electromagnet 120 which, as clearly shown in Fig. l, is located on the front of the machine. The other terminal ofthe electromagnet 1204 is connected by means of a conductor 121 to the contact terminal 112 in the casing 117. As the adjacent contact terminal 111 in said casing is at that time connected to the terminal 112 by means of the contact or bridging member 110, and as the terminal 111 is connected to the terminal 31 by means of a conductor 122, the electromagnet 120 is energized, it being understood that the levers 27 and 29 are grounded into the machine frame asindicated 'in the wiring diagram and that one terminal of the generator G is grounded into the machine frame by a ground wire 123, as is `also indicated in said diagram. Referring now to Figs. 1 and 13, an armature 124 is located above the electromagnet 120 which, together with an upwardly extending arm 125 and a depending arm 126, all of which are' conveniently made as one, are pivotally mounted on a stud or from the front of the achine frame. upper end of the armnl25 provides an upwardly inclined surface which normally lies in the path of, but beneath a pin 8a which projects forwardly from the left hand table dog 8; when, responsive to the energization of the electromagnet 120 as described, the armature 124 is drawn downwardly, the upwardly inclined portion of the arm 125 is The projected into the path of the pin 8a and, as

the table. 1 moves to the right next following such energization, the pin 8a rides on the said inclined surface and is lifted clear of the portion 11 of the reversing member l0, and the table 1 continues its movement to the right unaifected by the dog 8.

Coincidentally with this action, and by reason. of the energization of the magnet 120, the depending arm 126 is moved to the right, thereby shifting a slide valve 128 to the right, wl'rich makes the pressure fluid acti'i'e through branch piping 1,29 shunted into the main piping 35 to a cylinder 130, which contains a piston 131, the movement of the latter being adapted to lower a dressing device or diamond 132 into the path of movement of the grinding wheel 5. The flu-id pressure connections and some ofthe parts for this operation are indicated dia grammatically in Figs. 3 and 14, and the diamond 132, which is mounted on an oscillatable carrying member 133 is shown in Fig. 1, but the details of its operating mechanism need not be further described herein, since they form no part of the present invention, being fully described in the copending application of Heald-and Guild, Serial No. 25,900, ined. Apr-i125, 1925.

As the table 1 continues its movement to the right, carrying the rotating grinding wheel 5 out of the workpiece, the cam member 89, carried by the block 79, engages and depresses the roller 90 on the arm 91 and thus, by means of the escapement mechanism described, causes a second actuation of said mechanism, and this-turns the shaft 75 far enough tocarry the contact member 11() to a position between the terminals 111 and 112 and the terminals 113 and 114. See Fig. 13. Subsequently, the wheel 5 contacts with the dressing diamond 132, which has been lowered into position as aforesaid, and is dressed and trued thereby; thereupon the pivotally mounted dog 82 strikes the right hand portion 11 of the reversing member 10, and reverses the direction of travel of the table 1, said table carrying the grinding wheel 5 past the dressing device again and back into the workpiece. At the outermost limit of amplified travel of the table 1, a cam member 134, which is in the same vertical plane as the upwardly extending arm 125, and which is carried by the block 81, engages said Aupwardly extending arm and returns it, and the armature member 124 and depending arm 126 to their initial position, thus moving the slide valve 128 to the left and relieving the diamond actuating cylinder 130 from the fluid pressure. Since the elec tromagnet 120 was deenergized when the shaft 7 5 was turned the second time, as just described, there is no danger of these parts moving again, and indeed, no further energization of the magnet 120 to cause dressing and truing` of the wheel 5 can occur on this particular grinding operation. The return motion of the table 1 causes the diamond carrying member 133 to be raised to the position shown in Fig. 1, but the mechanism that performs this action forms no `part of my invention.

Thereturn motion of the table 1 also causes the cam member v89 to depress the roller 90,

resulting in a third angular movement of the shaft 75, carrying the contact member 110 into engagement with the two terminals 113 and 114. rThe grinding wheel 5 now proceeds to take the vfinal and finishing cuts on the workpiece, the termination of this final stage together, causing of the grinding operation being brought about by the engagement of the cam member 25 with the screw 28, responsive to actuations of the pawl 20 by the engagement of the cam 13 with the roller 16. When this occurs, the contacts 32- and 33 are brought energization of an electromagnet 135 located on the front of the machine frame directly behind the electromagnet 120.

Referring now to the wiring diagram of Fig. 13, this energizationoccurs in the following manner. The electric current proceeds by way of` the branchingdead 119 through saidelectromagnet 135, thence by way of a conductor 136 andthe left hand branch 136e thereof to the contact terminal 114; thence through the contact member 110 to terminal 113 and, by way of branch 137e andimain conductor 137 to the terminal 33. As this terminal is then engaged by the terminal 32, the current goes through the lever 29 to ground and, by way of the ground wire 123, to the generator Energization of this electromagnet 135. attracts an armature-'member 138 located above the electromagnet and just behind the armature member 124 and which, together with an upwardly extending arm 139 to which it is attached, is pivotally mounted on the same stud or shaft 127 on which the three members 124, 125 and 126 are mounted. The arm 139, as well as the arm 125, has an upwardly extending inclined surface and, as bestshown inFig. 9, this surface lies behind the similar surface of the arm 125, andlies directly in the path of the two 'pivotally mounted dogs 8 and 82. Lifting of the arm 139, therefore, causes said dog 8 to be lifted above the right hand portion 11 of the reversing member 1() and the table 1 therefore proceeds to the right unaffected by said reversing dog, but it will be noted that during this phase of the cycleof the machine operation', the diamond carrying member 133 is not moved. The table 1 continues toy the right and the cam melnber 89, carried by the time, thus moving the contact member 110 into engagement with the terminals 115 and 116. This movement of the contact member 110, however, does not de-energize the electromagnet 135, for the reason that a branch-1362 of the conductor 136 is connected to the terminal 116, and a branch 13712 of proceeds by a .block 79, engages the rollerv 90 for the fourth ist which is in line with the engagement of the stop 54a with the lever 54, in a manner similar to that shown and described in Patent No. 1,582,468 and described earlier in this specification. The machine has now completed one cycle of operation and is in exactly the same condition as described at the commencement of this description of operation.

In a previous part of this description, it has been related that the pressure fluid which gives the table 1 its reciprocatory motion, including the amplified movement of travel and the movement of withdrawal described, is taken from the main fluid supply line 35, by way of a branch line 36, to the control valve 37 which determines the speed of travel of said table at any instant. Referring now te Figs. 10 and 11, this valve comprises a casing indicated by the aforesaid numeral 37, which has a central vertical bore 140 therein, closed by a member 141'at the bottom, and by an overhanging portion 142 at the top, the latter having a small bore just large enough to permit the shaft to pass therethrough. The valve member 118, heretofore referred to is fastened to the bottom of the shaft 75 in any suitable manner and completely occupies the bore 140 except for a small space at the top in which is located a thrust bearing 143 adapted to take the upward thrust on the valve member and shaft, due to the pressure of the fluid. rlhe valve member 118 has a vertical bore 144 which is closed at the top by the shaft 75, but the fluid, which enters the bore 144 by way of a channel 145 proi vided in the closure member 141, (said channel having a centrally located orice which is therefore always in communication with the bore 144) can leave the bore 144 by way of a port 146 in the side of the valve member 118. Extending partly around the valve member 118, and at the levelof the port 146, is a quasi-annular passage 147 formed in the casing 37. Said passage 147 communicates with the piping 38 that leads to the table reversing valve 48, and it also communicates with the bore 144, by means of a plurality of ports, five in number in this embodiment of the invention and numbered 148, 149, 150, 151 and 152, respectively, in counterclockwise rotation. Obviously, however, the fluid can only flow through that one of these five ports port 146 in the valve member 118.

Radially alined with the ports 148, 149, 150, 151 and 152 are a series of bores 148e, 149e, 150a, 151a and 152er. The first and last of these are made solely for the .purpose of drilling the ports 148 and 152, which otherwise could not very well be reached with a drill, and they are therefore threaded and provided with closing plugs of any suitable description. The bores 149cv, 1505, and 151a,

however, are each provided with adjustable screw threaded devices for regulating the amount of pressure fluid that ows through their corresponding` ports 149, 150 and 151, respectively, and these devices, being all the same, will be described in connection with the port 150, the regulating device for that port being shown in F ig. 10.

As shown in said ligure, the bore 1500. is closed with a screw threaded member 153, which itself is internally bored and threaded, an adjustable screw plunger 154 fitting therein. The latter can be turned by means of the knob 155, and provides a closure portion 156 alined with the port 150, said closure portion advancing or receding from said port as the plunger is turned. rThe effective opening through the port 150 can, by the above means, be varied with a great degree of accuracy. To make this device fiuid tight, a packing v157 fits around the plunger 154 in the bore 150er and may be compressed between the threaded member 153 and a washer 158.

From the foregoing description, bearing in mind the fact that thevalve member 118 is attached to the shaft 75 and, therefore, must turn with it, it will be apparent that the speed of the grinding table or carriage 1 can be accurately regulated for all 'the various phases of the grinding operation described. Briefly, recapitulating, however, the valve member 118, at the commencement of a grinding operation, is in that position where the port 146 in said valve member is alined with the port 148 in the casing 37, and therefore, the table 1, on its inward movement to carry the grinding wheel 5 into the hole in the workpiece, moves at its maximum rate of speed, unrestricted by the valve means of the present invention and limited only by the setting of a valve located in the reversing valve casing 39, which is controlled by a lever 159 on the front of the machine, this control being common in grinding machines of this class. To all intents and purposes, and so far as the present invention is concerned, the table travels to the left at its full speed, until the cam member 89 engages the roller 90 and causes actuation of the shaft 75 as described; whereupon the valve member 118 is moved to that angular position where the port 146 is in line with the port 149. At that time, or immediately subsequent to it, the grindin wheel 5 has entered the workpiece andthe grinding operation has commenced. This preliminary grinding operation to take the coarse cuts on the workpiece, with the table 1 travelling back and forth on a reciprocation of limited range, takes place at a speed determined by the setting of the adjustable screw plunger 154 that controls the flow of liquid through the port 149 which may be anything within the limits of setting of said plunger, but ordinarily will be afairly fast traverse, in order that too much time may not be consumed in getting the workpiece ground approximately to size.

When the workpiece has been ground approximately to size, the cam member, on the cross feed wheel 23, comes into contact with the adjustment screw 26 and the dressing operation is inaugurated as already set forth; just before` Contact between the grinding wheel and the diamond, the cam 89 again contacts with the roller 90, and the valve member 118 is, inv consequence, moved a second time, bringing the movable port 146 in line with the port 150. When the wheel contacts the diamond 132, therefore, both travelling outwardly and also as said wheel travels inwardly, thespeed of reciprocation of the table 1 is determined by the setting of 'the adjustable screw plunger 154 that controls the effective opening through the port 150, which again can be'anything within the limits of adjustability of said plunger, but in this case is preferably very slow, so that the diamond will not cut a groove in the grinding wheel, but on the contrary, will dress and true it to aperfect cylindrical surface.

As the table 1 travels inwardly after the dressing operation, the cam member 89 strikes the roller 9() for the third time, and the port 146 is shifted to thatposition where it lines up with the port 151. 'lhe setting of the adjustable screw plunger 154 that. controls the passage of the fluid through this port 151 tti will vary somewhat according to the requirements of tolerance forthe workpieces being ground, but generally it will be to cause the table to travel faster than it did during the dressing operation, but slower than during the preliminary grinding operation. At all events, the wheel now proceeds to take the final and nishing cuts on the workpiece until such time as the cam member strikes the second adjustable screw Q8, which signifies that the grinding operation is completed; whereupon the table 1 is caused to travel to the right to the position shown in Fig. 1, as already described, and the commencement of such action moves the valve member 118 a fourth time, bringing the port 146 opposite the port 152, so that the table moves to its position of restat maximum speed, allowing the operator to remove the linished workpiece from the chuck at the earliest possible moment.

l claim,

1. ln a grinding machine, the combination with a, grinding wheel, work holding means, and a table or carriage carrying one of said parts, of fluid pressure means to reciprocate said table or carriage, a valve comprising a main port, a second main port, a further plurality of ports always connected to the first main port but not to the second, and a single movable member which in each position connects one and only one of said plurality 'of ports to the second main port, and means for shifting said single movable member to cause the table or carriage to move at.dierent speeds.

2. ln a grinding machine, the combination with a grinding Wheel, work holding means, and a table or carriage carrying one of said parts,- of fluid pressure meansto reciprocate said table or carriage, a valve comprising a main port, a second main port, a further plurality of ports always connected tothe first main port but not to the second, and a. single movable member which in each position connects one and only one of said plurality of ports to the second main port, and means controlled by said table or carriage to shift the position of said movable member.

3. ln a grinding machine, the combination with a grinding wheel, work holding means, and a table or carriage carrying one of said parts, of fluid pressure means to reciprocate said table or carriage, a valve comprising a main port, a second main port, a further plurality of ports always connected to the iirst main port but not to the second, and a single movable member which in each position connects one and only one of said plurality of ports to the second main port, and escapement controlled means to actuate said single movable lmember to cause said table or carriage to move at varying speeds.

. 4. In a grinding machine, the combination with a grinding wheel, work holding means, and a table or carriage carrying one of said parts, of fluid pressure means to actuate said table or carriage, a valve comprising a main port, a second main port, a further plurality of ports always connected to the first main port but not to the second, and a single movable member whichin each position connects one and only one of said plurality of ports to the second Vmain port, escapement controlled means to actuate said single movable member, and means controlled by lsaid table or carriage to actuate said escapement,

5. ln a grinding machine, the combination with a. grinding wheel, work holding mea'ns, and a table or carriage carrying one of said parts, of Huid pressure means to actuate said table or carriage, a valve comprising a main port a second main port a further plurality of ports always connected to the first main port but not to the second and a single movable member which in each position connects one and only one of said plurality' of ports to the second main port, fluid pressure means to urge said movable member in one direction, escapement controlled means to allow said fluid pressure means to actuate said movable member to progressively cause said table or carriage to move at different rates of speed. and means to cause said fluid pressure means to urge said movable member in 'the opposite direction for the performance of a new cycle of grinding.

6. ln apparatus as claimed in claim 1, the

combination with the parts therein specified, of adjustable means to adjust the flow of iiuid through some of the plurality of ports.

7. In apparatus as claimed in claim 2, the combination with the parts therein specified, of adjustable means to adjust tlie`iow of liquid through some of the plurality of ports.

.8. In apparatus as claimed in claim 3, the combination with the parts therein speci-fied, of adjustable means to adjust the flow of liquid through some of theplurality of ports.

9. ln apparatus as claimed in claim d, the combination with the parts therein specified, of adjustable means to adjust the flow of liquid through some of the plurality of ports.

l0. ln apparatus as claimed in claim 5, the combination with the parts therein specified, of adjustablemeans-to adjust the flow of liquid through some of the plurality of orts.

l1. In a grinding machine, the com ination with a grinding Wheel, means tocause said grinding wheel tort-alie preliminary or roughing cuts on a: workpiece, electromagnetic ificalisto cause 'the cuts to bek changed to thejinal andjnishing cuts, and electromagnetic means to cause the grinding operation to he terminated, of a rotatable electric current distributor .mechanism\a fluid pressure motor directly connected to said distributor mechanism to actuate it, and escape- Inent operative means to allow said mechanism to be actuated.

12. 'In a grinding machine, the combination with a grinding wheel, means to cause said grinding wheel to take preliminary or roughing cuts on a workpiece, means to causethe cuts to be changed to the final or finishing cuts, and means to cause the grinding operation to be terminated, of a valve com prising a main port, a second main port, a further plurality of ports always connected to the first main port but not to the second, and a single movable member which in each position connects one and only one of said plurality of ports to the second main port, and escapement controlled means to operate said movable member to control the rate at which a workpiece is cut.

13. In a grinding machine, the combination with a grinding wheel, means to causo said grinding wheel to take preliminary or roughing cuts on a workpiece, electromagnetic means to cause the cuts to be changed to the final or finishing cuts, and electromagnetic means to cause the grinding operation to be terminated, of a rotatable valve to control the rate at which a workpiece is cut, escapement controlled means to operate said valve, and a distributor directly connected to the movable part of said valve to determine which phase of the grinding operation takes place.

14. In a grinding machine, the combination with a grinding wheel, work holding means,

and a table or carriage carrying one of said parts, of a reversing member -to control the direction of travel of said table or carriage, a pair of adjustable table dogs to actuate said reversing member, one of said dogs being pivotally mounted and adapted to be lifted to allo-w it to pass said reversing member, a third adjustable dog, pivotally mounted and carried by said table or carriage beyond said iirst mentioned pivotally mounted dog, means interposable in the path of said rst named pivotally mounted table dog to lift the same and allow the table to move beyond its normal working stroke, but to be reversed by the'second pivotally mounted dog, and means interposable in the path of both of said dogs to allow the table to move beyond b'oth of them.

l5. lin a grinding machine, 'the combination with a grinding wheel, a work holding device,`

a table or carriage carrying one of said parts, fluid pressure'means to move said table or carriage, ,means to cause said fluid pressure means to operate said table or carriage through a limited reciprocatory traverse, work sizing mechanism, a dressing device, electromagnetic means to cause the traverse to be amplified, whereby to pass said wheel with said dresser, and electromagnetic means to cause the table to finally stop, said last two 'means being operated by said work sizing mechanism, of a single controlling device actuated between the several phases of the grinding operation as hereinbefore set forth and' adapted to regulate the flow of the pressure fluid, whereby to obtain dierent carriage speeds during the dierent operations, said device also controlling the aforesaid electromagnetic means to prevent more than a given amount of wheel dressing and to cause resumption of the grinding thereafter.

16, ln a grinding machine, the combination with a grinding wheel, a work holding device, a table or carriage carrying one of said parts, duid pressure means to move said table or carriage, means to cause said fluid pressure means to operate said table or carriage through a limited reciprocatory traverse, work sizing mechanismfa dressing device, electromagnetic means to cause the traverse to be amplified, whereby to pass said wheel with said dresser, and electromagnetic means to cause the table to finally stop, said last two means being operated by said work sizing mechanism, of a rotatable valve and distributor device, and means to actuate it between the several phases of the grinding operation as hereinbefore set forth, whereby to regulate the flow of pressure fluid to obtain diiferent carriage speeds during the diiferent operations and to control the aforesaid electromagnetic means to prevent more than a given amount of wheel dressing and to cause resumption of the grinding thereafter.

17` In a grinding machine, the combination with a grindingwheel, a work holding device, a table or carriage carrying one of said parts, fluid pressure means' to move said table or carriage, means to cause said fluid pressure means to operate said table or carriage through. a limited reciprocatory traverse, Work slzlng mechanism, a dressing device, electromagnetic means to cause the traverse to be amplified, whereby to pass saidy wheel with said dresser, and electromagnetic means to cause the table to finally stop, said last two means being operated by said work sizing mechanism, of a single controlling device, and fluid pressure means to actuate it between the several phases of the grinding 0peration as hereinbefore set forth, said device being adapted to regulate the iow of the pressure uid, whereby to obtain different carriage speeds during the different operations, said device also controlling the aforesaid electromagnetic means to prevent more than a given amount of wheel dressing and to cause resumption of the grinding thereafter.

18. In a grinding machine, the combination with a grinding wheel, a work holding device, a table or carriage carrying one of said parts, fluid pressure means t0 move said table or carriage, means to cause said fluid pressure means to operate said table or carriage through a limited reciprocatory traverse, and means to cause said table or carriage to withdraw the wheel from the workpiece at the end of a grinding operation, of 4a valve controlling the flow of fluid and governing the speed of said carriage during dilferent 4phases of a grinding operation, escapement controlled means to operate said valve, a valve device to cause said table to stop upon the withdrawal of said carriage, and a Huid pressure motor to reset the escapement controlled valve, this fluid pressure motor being controlled by the last named valve device.

- EDWARD M. TAYLOR.

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