US1662546A - Grinding machine - Google Patents

Description

March 13. 1928.

A. P. STEINER GRINDING MACHINE '7 Sheets-Sheet l Filed. June 20. 1924 'Mrch 13, 1928. 1,662,546

A. P. STEINER GRINDING MACHINE Filed June z. 1924 7 sheets-sheet 2 March 13, 1928.

A. P. sTElNr-:R

.GRINDING MACHINE Filed June 20. 1924 7 She'etsSheet 5 K) ...V A111051). .Siener' MSH atbofcnut March 13, 1928.

A. P. STEINER GRINDING MACHINE Filed June 2o. 1924 H 7 sheets-Sheet atteint m A. P. STEINER' GRINDING MACHINE March 1 3, 192,8.

Filed June 2O. 1924 7 Sheets-Sheet 5 A. P. STEINER GRINDING MACHINE March 13, 1928.

Filed June zo.

1924 '7 Sheets-Sheet 6 March 13, 1928.

' A. F'. STEINER GRINDING MACHINE 7 Sheets-Sheet 7 Filed Jun'e gjm uch l'oL AmoS P. bis# ner Chimney;

Patented Mar. 13, 1928.

UNITI-:D STATES PATENT oFFicE.

AMOS P. STEINER, 0F WAYNESBORO, PENNSYLVANIA, ASSIGNOR T0 LANDIS TOOL COMPANY, OF WAYNESBORO, PENNSYLVANIA, A CORPORATION 0F PENNSYL- vANIA GRINDING Application filed June 20,

My said invention relates to grinding Inachines and it is an object thereof to providev a machine for grinding twist `drills and other small cylindrical objects with a magazine feed which shall operate at predetermined intervals to discharge from the workholder the .completed articles and replace them with articles to be ground.

Another object of the' invention is to provide a fluid motor for operating the replenishing mechanism and' means for setting the motor in .operation at predetermined intervals. Y

Another object of the invention is to provide means for moving the grinding wheel toward and from the work during operation upon asingle article.

' Still another object is to provide means whereby the movement of a traversing carriage sets in operation the motor above re-' f'elred to, reverses the fluid motor for the traversing carriage and actuates the means for moving the wheel toward and from the Work.

Referring to the accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts,

Figure 1-is a front elevation of a machine embodying my improved mechanisms,

Figure 2, an end elevation of the same,

Figure 3, a detail 'of a cam shown in Fig-V ure 2, I

Figure `4, aI front elevation of the maga-I zine operating motor with parts broken away for the sake of clearness, this figure and the remaining figures being on an enlarged scale,

Figure 5, a vertical section of said motor,

'ratchet mechanism used 1n connection with said motor,

Figure 7, a plan View of the work centers, a work transferring slide and means for operating said parts, .A.

Figure 8, an end elevation of the magazine. its motor and other auxiliary parts,

Figure 9, a front elevation of parts shown in'Figure 7, i

Figure 10,. a composite end elevation of Acertain cams in Figure 8,

Figure 11,"a much enlarged front elevation of a dog shown in Figure 1,

Figure 12, an elevation of parts shown in Figure- 6, a vertical section of pawl' and vcarriage driving motor.

MACHINE.

1924. seran no. 721,292'.

Figure l() looking atsaid ligure from the right-hand side, and

a part shown in Figure l1.

` In the drawings referencel character 20 indicates the frame of the machine which may be of any conventional or desirable form being here shown as hollow and provide with suitable openings, doors, bearings, etc., all as is customary in machines ofthe same Figure 13, a detail on la reduced scale of general character'. An abrading device in vthe form of a wheel is illustrated at 21, said Wheel being located on a shaft 22 carrying a pulley driven by a belt 23 passing over another pulley on the. shaft 24 which is driven from any suitable source of power.

A traversing carriage is supported on the machine frame in front of the vgrinding wheel said carriage supporting a depending rack 25 (Figs. 1 and 2). A pinion 26 has teeth engaging those of the rack, said pinion being supported on a shaft 27 which also supports a fluid motor having a rotor whose actuating .element is a vane 28. An inlet pipe 29 leads from a tank 3() to a pump diagrammatically illustrated at 31 said pump having a shaft 32 driven b a chain 33.

From .the pum i the iluid un er pressure is l -lcd by way o pipes 34 and 35 to valve mechanism including reversingfdevices opthe exhaust fluid back to the tank together with such fluid as may be by-passed from the pressure valve. A branch pipe 39 connects with the ipe 34 and this leads to a flexible pipe 40, t e entrance to which is controlled y a (valve 41 having an operating lever 42. The `last-named pipe leads to a motor on the traversing carriage having a valve at 43 .(Fig. 4) for controlling the entrance and exit passages. A flexible tube 44 leads from the last-named motor to a return pipe 45 by which the pressure .fluid is carried back to the tank, a ipe 46 also connecting therewith toV return uid by-passed from the casing of the valve 41. A valve 47 is provided for cutting olf the flow of pressure-fli1id to the l Y traversing work cam'age. The traversing work carriage in addition to the rack 25-carries a magazine 48 here 4shown as having an upwardly opening inclined chamber 49 which is long and narrow to accommodate objects 50 of a slender cylindricall form, such as twist drills and similar objects. At its lower end the magazine is supplied with a guide 51 which is preferably 4resilient and underneath which the articles of work pass to the working position. At the other side of and approximately directly below the'magazine is a lip 52 pivotally supported at 53 on a slide 54 said slide having a depending lug 55 located in opposed relation to a depending lug 56 on the lip 52 between which lugs a secondary slide 57 is located, said slide having a lost motion connection with the depending lugs 55 and 56 whereby on forward movement of ythe secondary slide the upper slide is projected with the lip held up in the position shown in Figure 8 whereas on return movement of the secondary slide withdrawal of said slide from the lug 56 permits the lip to move about its pivots into a position to clear the work held in the work centers hereinafter described and thereafter by engagement with the lug 55 the secondary slide acts t0 retract the upper slide and the pivoted lip.

The secondary slide has a transverse notch at 58 in wh-ich is located the end of a rockarm 59 fastened to a rockshaft 60, said shaft having another rockarm 61 bearing a pin 62 located' in a laterally' opening cam slot 63 of a 'cam 63.

A. pair of work centers 64 and 65 are located in position to engage the twist drill or other similar piece of work shownat' 66. One of said centers is in effect a swivel held in a sleeve 67 movably positioned in a bearing 68, a spring 69 acting to hold it normally in the advanced position. The other centeris surrounded by a sleeve 70 splined to a shaft 71 near its end. Said shaft'is supported in suitable bearings and carries a' pulley 72. The sleeve 70 is forced toward the right to its advanced position by a' spring 73 surrounding the shaft. The sleeve 70 has a slot in its forward end adapted to receive the flat tang of'a twist drill for driving the same, the sleeve thus providing what -in effect is a chuck for the drill.

A pair 'of levers 74 and 75 are pivoted respectively at-opposite sides of the magazine 48 and saidlevers are provided at their- rear endswith rollers 76 and 77 acting as followers for cams 78 and 79 located on a shaft 80 l centers above described.

The work changing motor.

` For .driving the camshaft 8() which operates the work changing means consisting of the means for separating and returning the work centers and the means for operating the slide 54 and its connected parts, I have provided a fluid motor shown in detail in Figures 4 and 5 and in a more general way in Figures 1, 2 and 8. rlhis motor comprises a casing or stator having a body 81 and end pieces 82 secured together in any convenient manner as by means of bolts or rivets 83. lVithin the housing thus formed there is a rotor having a vane84 connected in an convenient manner to the shaft 85. The movement of the rotor is limited by a block 86 to an oscillation of approximately 300, said block extending from side to side of the housing and being reduced at opposite sides to provide chambers communicating with passages 87 and-88 which in turn communicate with a valve chamber in which is located the valve 43. The valve chamber is provided with an inlet pipe 89 and an outlet pipe 90 and it will be evident from consideration of the drawings that according to the position of the double-headed valve fluid under pressure will be admitted through one or the other of passages 87 and 88 to drive the rotor in one direction or the other while at the sametilne an exhaust passage will be opened from the opposite side o'f the rotor through a passage 87 or 88 to the valve chamber and so to the exhaust pipe 90. The

pipes 89 and 90 are connected the flexible tubes 40 and 44 (shown in Figure l) so that the fluid from the tank 30 forced by the pump 31 through the tube 40 will be returned to the tank through the tube 44.

The shaft 85 near its righthand end supports a gear 91 loosely surrounding a ratchet. 92 splined to said shaft. The gear has pivotally supported thereon adjacent to the. ratchet apawl 93 forced toward the ratchet by a spring 94. rll`he gear 91 meshes with a gear 95 on .the cam shaft 8O of the work changing mechanism and it will be evident that the motor drives the work changing mechanism on its working stroke through the pawl and ratchet mechanism which workingstroke is followed by an idle stroke in which the work changing mechanism remains stationary.

The valve43 has a stem 96 projecting toward the left-hand end of the carriage and ahead 97 on the stem. A coiled spring 98 is located betweenthe head 97 and the cap 99 of a gland forming part of the valve casing so that the valve is normally held in its extreme left-hand position in which position of the valve the idle stroke of the motor takes place after which the rotor remains in the extreme opposite position to that shown in Figure 5. A fixed abutment 100 is provided on the frame of the machine, said abutment being fixed to or integral with a rod slidably supported in an opening of a respectively to post 101 and .being adjustably secured in position by a. set screw 102.

Wheel feeding means. `The grinding \vheel 21 is provided with any conventional or desirable supporting means including provision for adjusting the wheel toward and from the work to compcnsate for the decrease in diameter of the wheel due towear.

Wheel is moved back and forth from the work in the operation of grinding each in- 'dividualarticle 'of Work.

Preferably this operation is performed step-by-step in synchronism with the stroke of the traversingrrv work carriage so that as each stroke of the carriage 1s completed the wheel 1s advanced a dlstance correspondlng to the reduction 111 diameter ofthe Work during a stroke of the carriage. For this purpose the cap is provlded with one or more depending arms 101 a cam or cams 106. The cam is fixed to a shaft 107 having at one end a beveled gear 108 meshing with a beveled gear 100 rigidly secured to aratchet 110. A shaft 111 .concentric with the ratchet has a rock arm supporting a pawl 112 engaging the ratchet 110.` At lits front end the shaft has another arm113 adjustably connected 'to `the reciprocating work carriage by abutnients 114 located at opposite sides of the enlarged headof the rockarm and slidably adjustable in a slot 1-15 of the carriage.

'The machine here illustrated .is arranged to grind a twist drill Ito the desired extent by four strokes (which number may be varied as desired) and as will be seen in Figure 3 the cam as here designed serves to x control the Wheelduring the operationen two twist drills, said cam having two series. of steps a, b, c, and d so formed `that after step d the Wheel is returned to its outermost position byl a relatively high. and steep iii-- eline after which it may be movedstep-bystep toward a position closer tothe axis of the Work`by springs 1.16 arranged to actl on lugs 117 depending'fromy the cap so as tto forcethe cap and thereforethe Wheel towardfthe work. It Will be seenthat the springs act constantlylto forcethe wheeltoward its most advanced position which action is opposed by the cams but this ar'- rangement can be reversed-if desired. Due

to the factgthatthe machine makes shortthrough a considerably larger arc and',v therefore feed the ratchet for a greaterdistanea it 'is important to4 provide means to prevent the parts of the machine from vgetting out jof time and for this purpose'I have pro".-

In' additiontov this -a sliding cap 103 is provided by which the vided af shield 112 extending underneath 4the pawl and adapted to liftit out of engagement with the ratchet teeth on the long stroke, or otherwise expressed the shield limits the actual working stroke of the pawl to a vpredetermined number of teeth which is uniform for both the long and the short i strokes of the carriage.

V)Stroke controlling mechanism. rllhe operationrof the` machine is such thatv vthe table or carriage has two strokes of equal length followed by along stroke'which removes the work from the 4wheel and the v workholders. During the long stroke the completed work is removed and an unfin- 1 ished-article taken from the magazine is v strokes for each article which number may provided with followers 105 coactmg with of course be varied as may be found desir' able. For the purpose indicated `and for other purposes the carriage-is provided with a pair of dogs 118 and 119 (Fig. l), one of which is shown in an enlarged forni in Figures 11 to 13. Each of the dogs is provided as usual with adjusting means consisting of a 'Worm' 120 engaging teeth on a rack bar 121y of well-known character on thefront of the machine. The dog 119 is provided with a vertically slidable stop member 123 urged in one direction by a spring 124 and said .stopl member is adapted at itsA lower end to' lever 36 for inoving the valve of the carriage 1 operating motor in one direction. At each stroke `of l,the carriage toward the left a roller 126 on the dogengage's a' cam .127 fixed to the fran'ie of the machine, said roller being mounted on a lever 128 pivoted at 129 Y and carrying at'its free end a pivoted pawl 130 engagingwith ratchet .teeth 131 at the side of the stop member 123 which may approprlately be designateda ratchet bar. The

rise of the caml is such that the pawl will lift the stop member only o ne tooth at each stroke. A detent pawl 132 pivoted` at 132' isyforced toward the rack teeth by a spring 133. A similar spring 134 serves to force the pawl 130 toward said teeth. i

' 'A stop 135 is mounted on the dog'119 to the right ofthe stop 123 this stop servingvto -strike the bloc-k 125 and reverse the lever 36 when the'stop 123 has been elevated so high as to miss' saidblock or on-the fourth -stroke of the carriage fora piece of'work.

The stoptis fiattened at its lower end and has a head 136 at its upper end by which it may be lifted'against Athe tension of the spring 137 if a still longer stroke of the carriage is `des1red,` e.- g. to-move 1t out of the Way of the'g'rinding wheel as for repairs or. resurfacing of the AWheel. f

les

. After the; -stop 1123 Vhasfbeen lifted to its full extent (as indicated in Figure 11) the s 139- pivoted at 140-strikes a trip l141 fired. to

the frame of the machinethereby swinging said lever 'in a counterclockwise direction about its pivot.' vvThe lever has cam surfaces enga ing pins 142 and 143 extending laterally rom therespective pawls-13() and 132 4 and thesecam surfaces act on the'pins to 13'1,the llever 139 forming 'in eii'ect a pawllifter fordisengaging lsaid pawls, whereupon the spring 124 immediately forces Vthe stop '123 downward.v The downward movement .is llimitedby har orp'late 144 ofJ a height to prevent the stop from engaging the block Y 125 oli -theanextmovement toward the right for which purpose inthef present embodiment of the 'invention the bar is shown as having a cam incline to Secure sufficient 2a. the right thetail end ofthe pawl lifter 145 height' for the stop. On such stroke toward strikes thetrip 141 and so is caused to release `the .pawlsl 130 land 13 2 whereupon their springs 133"and 1`34'1'eturn them to active position. The dog 119 carries'also a cam bar y thereof said bar eing secured in position by4 a set screw' 147. As the cam movesV toward the left with the carriage oneof its inclined surfaces engages a lever 148 for operating the valve 37 to diminishfthe'supply of pressure fluid to the carriage reciprocating motor and: thus retard vthe movement of the4 carriage. The bar has a horizontal surface ofsubstantial length between its ends so that Y Awhen thecarriage makes lits long stroke to Y' the leftitwill travel -slowly during the excess movement toward the left and also duringthe return movement until 'it reaches the position where ordinary grindingoperation begins... similar ca n 149 on the other dog` provides for retardation of the vreciprocation ,as the carriage reaches the end of its stroke .'to/tl'ieright. i

'In theA operationof my device the valves 4 1 and 47 being opened and the pumpbeing .'set in operation Huid underpressure is vad- -niitfted to the carriage reciprocating motor for driving it in one directionor the other 'as the case may be. Thereupon the carriage moves for example towardthe left carrying lwith it the magazine andother elements of the work replenishing mechanism, the dogs 118 and 119, the stops 114 eter, the' rockarm l113 swinging to the left at this time and the pawl 112v riding freely over the ratchet teeth. lAssuming the 'stroke to be of ordinary nature the carriage will move until the lower end of the slide 123 engages-block 125 and f tial. 'As the article 66 means.

reverses the positionof the lever 36, this being the position illustrated in the drawings, the carriage slowing down as usual near \the end of the stroke. rlhe direction of 36 a lug at its lower end strikes the block disengdge the Pawls from# the rack teeth' l5.

until the last stroke which .completes the grinding operation on the article 66.

On the final stroke, the relative number of which is determined by the number of teeth 131`on the ratchet bar, the lower end of said bar has been raised so high thatv it passes over the block 125 and fails to reverse the 'lever 36. The cam 146 does,

of. the carriage which preferably` travels more and more slowly as it approaches the end of thestroke. y This movementmay be varied and the `carriage may even stop at the however engage the lever 148 to slow down the travel end of the long stroke lif necessary. 'lhe stroke continues until the` stop 135 strikes the block on the reversing lever and forces it past eentral'position after which springs or other-devices well understood in the art throw it quickly toward extreme position'. As the carriae approaches its extreme left-hand position t e head 97 of the valve of the work replenishing` fiuid motor strikes the fixed abutment 100 and admits the fluid under pressure Yto the interior of the stator on the 'carriage whereupon the shaft 85 is revolved in the direction of its working stroke, oper,

ating theca'm' shaft 80 so that the cams 78 and 79 actuate levers 74` and 75 to withdraw the .chuck 7() and the swivel support 65, it being understood that the cam 79 is preferably arranged to operate slightly in advance of the cam 78 thon h this is noty essenalls into whatever receptacle may be 'provided'for .it the slide 57 is being advanced carrying Iwith it, the slide 54 and lip v52shown in the position in Fi re 8 thereby transferring the lowermost rarticle in the magazine to a position between the chuck and the swivel support. The cam 79 being slightly in advance of cam 78 the swivel 65 will contact Withthe'work and work.

Intlie` long traverse of the earria e the parts are moved. sofar that the hwive 65'is plenishing' operation is completed the stop 135 will preferably have actuated the reversing lever and started the carriage in the opposite direction, it being understood that the ratchetxbalr 123 has been released Iby engagement of the pawl lifter 139 with the stop 141 said pawl lifter being `now returned to its original position tofreathe' pawlsby engagement of the tail thereof with trip 141 on the return movement. As the carriage moves to the right the head 97,is held against the abutment 100`by expansion of the spring 98 until the valve has Imoved far enough to reverse the connections of the passages 87 kand 88fto the tubes 40 and 44 wherey upon the fluid under pressure enters at the opposite side of the plate 84 and forces the rotor back on its idle stroke to itsoriginal position. The camshaft 80 has completed its stroke during the working stroke of the motor and the slide 57 being retracted has first released the pivoted lip 52 to allow it y, to fall out ofthe way of the Work ,between the centers and then has retracted the slide 54. y During the actual grinding operation it will be understood that the grinding wheel which is now at its position farthest fromu the axis of the Work will be returned stepby-step through the operation of the springs 116 andthe cam 106 after which one of the high steps of the cain will move it again to its farthest position prior to work replenishment.Y y Y `It will .be obvious to thoseskilled yin the art that my machine and the principle thereof may be changed in various ways without departing'from the spirit of the invention and that it may be applied to variousv uses.

For example the wheel might be' mounted on a traversing carriage, the magazineV mi ht'4 be on the fixedA frame and many ot er v' changes are obviously within the 'contemplation of the invention. Therefore I do not limit myself to the Vspecific embodiment vshown in the drawings `anddeseribed intheM appended claims. 1 l

Having thus fully described m said invention, what ,1I claim as new an desire to secure by Letters Patent is: c.

1. In a rindingmachine, abrading means, work-hold'ng means, a carriage for one of said means having traversing movement relatively to the other, a workholding ma azine, means for successively feeding un nspecification but only as indicated in the vished articles from the magazine to the workholdingV means, a fluid motorfor operatin "said feeding means, and connections A where y the traversing carriage Sets the of the slide to permit the lip to fall motor in operation at predetermined substantially as set forth. t

2. Inr a. grinding machine, a rotary wheel, a Workholder, a traversing carriage for the workholder, a'magazine on the carriage, a

times,

fluid motor, a fixed abutment, and means on vmovable towardy and from each other, a

magazine, a slide for carrying articles from the magazine to the work-centers, a pivotedp work-supporting lip at the front of the slide, and means for successively separatingk the work-centers, advancing the slide, returning the wo1"k-ce11ters,and retracting the slide including a camshaft and connections therefrom for supporting the lip positively during the advancing movementof the slide and permitting it to drop during the retracting movement, substantially as s et forth..

5. In` a grinding machine, work-centers movable toward and fron'r each other, a magazine, a slide for carrying articles from the magazine to the work-centers, a pivoted work-supporting lip at the front of the slide, a camshaft, and connections from the same to the Work-centers and the slide for succes-` sively separating the centers, advancing the slide, returning the centers, and retracting the slide, said connections including a lost motion connection for supporting the lip positively on its forward movement and releasing it on backwardmovement, substantially as set forth.v i-

movable toward and from each other, a magazine, a slide for carrying articles from the magazineto the work-centers, a pivoted work-supporting lip atA the front of the slide, a camshaft and connectionsv from ythe i same to the Work-centers and the slide for successively separating the centers, vadvancing the slide, returning the centers, and retracting the slide, said connections including a lost motion connection for supporting the lip on its forward movement and releasing it on backward movement, a fluid motor geared to the camshaft, and'means for startmgthe motor after a predetermined `grinding operation, substantially as set forth.

In a \grinding' machine, a grinding wheel, a traversing carriage, a fixed abut- 'ment, and devices on the carnage including 6. In avgrinding machine, Work-centers l ay Workholder, a magazine, means for feeding articles from' the magazine to the work- -holder, a fluid motor operatin said means,

and a valve for admitting Hui under presarticles from the magazine to the work controlling meansoperated by the impact holder, means for separating the work holder to release a finished article and'take up the articles supplied thereto by said feeding means, a fluid motor for operating said devices, and a valve for admitting fluid under pressure to said motor,y said valve being operated' by said abutment in a predetermined position of the carriage, substantially as set forth.

9. In a grinding machine, a grinding wheel, a traversing carriage, Ia fixed abut-v ment, and devices on the carriage including a workholder, a magazine, a slide to carry articles from the magazine to the workholder, a pivoted lip at the front end of the slide, a iuid motor, connections from the motor for separating andreturning the Workholder and for reciprocating said slide, said connections including lost motion connections to saidlip whereby it may fall awa from the work when the slide is retracte and avalve for admitting fluid under pressure to said motor,said valve being operated by said abutment in a predetermined position of the carriage, substantially as set forth. v

10. In a grinding machine, a grinding Wheel, a 4workholder, a traversing carriage for the workholder, a uid motor for actuating the carriage, a fluid motor on the c arriage, means actuated bythe second motor for feeding articles to the workholder, and

of the carriage for reversing the first-named .v motor `and for placingthe Aother motor` in opforth.

eration after a predetermined .number of traversing movements, substantially as set 11. In a grinding` machine, a grinding wheel, a Workholder, a traversing carriage for the workholder, a -liid motor for actuating the carriage, a fluid motor on the carf riage, means actuated by the secondmotor for feeding articles to the workholder, controlling means operated bythe impact of the carriage for reversing the first-named motor so, f

and for placing the other motor in operation after ai predeterminednumber of traversing y movements, means for moving the wheeltoward the workholder'step-by-step as the diameter of the work decreases and returnin 1t prior to the nextfeeding operation, land table for'one of said members, a base for the other adjustable towardand from the line of traverse of the table, :reap on the base, and ratchet operated by t e traversing `table, a cam moved by the ratchet, and a follower on the cap, said cam having hi h and low places arranged to separate tic table and the wheel to the fullest extent at a single step while permitting them to approach step-by-step as the work is reduced, substantially as set forth.

14; In a grinding machine, a rotary Workholder, a frotary grinding wheel, a traversing table for one of said members, a base for the other adjustable toward and from the line of traverse of the table, a4 cap on the base, means for moving the cap toward said yline during the grinding of an article and retracting it after such operation including a cam, a follower on the cap, and means actuated by the table for moving the cam step-by-step, substantially as set forth.

' 15. In a grinding machine, a rotary workholder, a-rotary grinding wheel, a traversing table for one of said members, a base for the other adjustable toward and from the line of traverse of the table, a cap on the base, means for moving the cap toward said line during the grinding of an article and retracting it after such operationincludin a rotary cam, a follower on the ca a rato et driving said cam, and a pawl t erefor ac- 16. In a grinding machine, a traversing table, a fluid motor for driving the same, a reversing lever for the motor, a pair of opposed do s on the table foroperating said lever at t e end of each traverse, and automatic means in connection with said dogs for producing a longer traverse after a pre y 'determined number of strokes, substantially as set forth.

17. In arinding machine, a traversing table, a lui motor for driving the same, a reversing lever for the motor, a pair of opposeddo on the table for operating said lever at t e end of each traverse, andmeans in connection withsaid dogs whereby a longer. traverse is permitted after a 'predetermmednumber of strokes, said means including a lthird dog in positionto reverse the lever at the end of such longer traverse, substantially as set forth.

18. In a grinding machine, a traversing carriage, a fluid motor'for driving the same, a reversing lever for the motor, a pair of opposed dog's on the table for operating said -lever at the end of'each tra-verse, pawl and ratchet mechanism actuated to move the stop on Vone of said dogs toward idle position on each stroke of a series thereby permitting a longer stroke at the 'end of the series, means for reversing the carriage after such longer stroke, and means to decelerate the travel of the table durin the excess portion of the stroke, substantialy as set forth.

19. In a grinding machine, a traversingv carriage, a fluid motor for driving the same, a reversing lever for the motor, a pair of opposed dogs on the table for operating said lever at'the end of each traverse, one of said dogs comprising a slidable bar vhaving' a u series of teeth, an actuating pawl for moving said bar to render the dog inoperative, a detent to holdthe bar, and automatic means for releasing the deteit, substantially as set forth.

20. In a grinding machine, a traversing carriage, a fluid motor for driving the same, a reversing lever for the motor, a pair of op'- posed dogs on the table for operating said lever at the end of each traverse, one of said dogs comprising a slidable bar having a.

series of teeth, an actuating pawl for moving said bar to render the dog inoperative,

a detent pawl to hold the bar, a lifter for said pawls, and an, abutment for actuating said lifter, substantially as set forth.

2l. In a grinding machine, a traversing carriage, a liuid motor for driving the same, a reversing lever for the motor, a pair of opposed dogs on the table for operating said lever at the end of each traverse, one of saidl dogs comprising a slidable bar having a serles of teeth, anactuatlng pawl for moving said bar to rendervthe dog inoperative, a detent pawl to hold the bar, a lifter for said pawls, means on the machine frame for actuating said lifter to release the pawls, and means also on the frame for returning said lifter to idle position, substantially as set forth. v

22. In a grinding machine, a traversing carriage, a reversing lever therefor, a dog .on the carriage having a part for actuating said lever, a fixed plate, means on the carriage engaging said plate onV successive strokes oia movesaid part of the dog incrementally toward idle position, and means thereafter re turning it to active position, substantially as set forth.

l23. In a grinding machine, a grinding Wheel, a traversing carriage for the work, means for replenishing the work at intervals, means for lengthening the traverse of the carriage at intervals, pawl and ratchet mechanism operated by the carriage tomove the to interrupt the action of said mechanism during the excess portion'of such lengthened traverses, substantially as set forth.

the carriage in one direction to 24, 4In a grinding machine, a grinding wheel, a traversing carriage for the work, means for replenishing the work at inter vals, means for 'lengthening the traverse of the carriage at intervals, pawl and ratchet mechanism operated by the carri-age to move 1the grinding wheel toward and from the work between replenishi operations, and means to lift said pawlnuring the excess portion of such lengthened traverses, substantially as set forth.

In witness whereof, I have hereunto set my hand at Waynesboro, Pennsylvania, this 17th day of June,A. D; nineteen hundred, and twenty-four.

4AMos P. STEINER.

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