US1872191A

US1872191A - Feeding mechanism for grinding machines

Info

Publication number: US1872191A
Application number: US436051A
Authority: US
Inventors: George H Smith
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1930-03-15
Filing date: 1930-03-15
Publication date: 1932-08-16
Anticipated expiration: 1949-08-16

Description

Aug. 16, 1932.

G.. H. SMITH 1,872,191

FEEDING MECHANISM FOR GR'INDING MACHINES Filed March 1551930 2 sheets-sheet 1 ATT RNEY Aug. 16, 1932. G. H. sMlTH 1,872,191

FEEDING MECHANISM FORV- G'RNDING MACHINES Filed Maron 1S, 1930 .2 sheets-sheet 2 Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE GEORGE M. SMITH, or WORCESTER, MASSACHUSETTSQASSIGNOR To NORTON COMPANY, OE WORCESTER, MASSACHUSETTS, A CORPORATION OE MASSACHUSETTS 'FEEDING MECHANJiSM FOR GRINDING MACHINES Application filedy March 15, 1930. Seri-a1 No. 436,051.

This invention relates to a grinding machine and more particularly to a feeding mechanism for a grinding machine wheel slide for controlling the movement of the4 grinding wheely towards and from the work.

in grinding pins of crankshafts it is necessary to move the grinding wheel rearwardly through a considerable distance after one pin has been finished in order to bring the neXt j@ pin into position for grinding. Heretofore, various mechanisms have been developed for rapidly moving a grinding wheel by power from this rearward position up to the work and then feeding it at a slow rate into the 1;. work until the desired size has been reached.

1t has been found in practice that the operators of these machines prefer, in many cases, to have the grinding operation under full control and carry it on at a rate and under suoli conditions as their own judgment and skill have determined to be the most satisfactory for the particular type of work being treated. Hence the power feed of the grinding wheel into the work has not, in every fr case, proven desirable. On the other hand,

if it is necessary for the operator to manually move the grinding wheel slide from its rearward position up into a grinding position considerable time and effort would be wasted 3o on his part and there would be danger of his carelessly feeding the wheel too far forward and accidentally ruiming it into the work at a rapid rate and so injuring the wheel or the work. It is therefore desirable that the grinding wheel be moved by power through that portion of its travel in which it is out of contact with the work. but that the grinding operation itself be left wholly to the judgment and skill of the operator.

1t is accordingly one obj ect of this invention to provide a cross feed mechanism for a grinding machine in which the wheel may be rapidly moved forward towards the work by a power mechanism to a predetermined position adjacent to the work, whereupon the power will `be automatically disconnected andthe wheel may then,v be fed manually until its further movement is brought to a. stop by an adjustable mechanism. j

VA further obj ect `of the invention is to provide a construction in which the points at which the power mechanism is disengaged from the wheel slide, and at which the kwheel slide is ultimately stopped, may be manually adjusted as desired.

A still further object of the invention is to provide a mechanism of this type which may be adjusted for a given work size, and then as the wheel wears away, the ultimate stopping position of the wheel and the position at which the power is disengaged may be simultaneously adjusted without changing their relationship to eachother.

Other objects will be apparent from the following disclosure.

Referring to the drawings which illustrate one embodiment of this invention and in which'like reference numerals indicate like parts:

Fig. l is a front elevation of the feed mechanism removed from the machine base Fig. 2 is a vertical transverse section, taken approximately on the line 2-2 of Fig. l;

Fig. 3 is a top plan view sho-wing the asl sembled mechanism; and 75 Fig. 4 is a fragmentary plan view of the mechanism, with a few parts removed to better show. the construction.

1n the embodiment of the invention illustrated in the drawings, acylindrical grinding machine is provided in which the wheel slide may be rapidly moved in either direction by means of a power driven cross feed screw. The wheel slide is also movable by a finely adjustable, manually operable mechanism, and the ultimate stopping position of the wheel relative to the finished work size is determined by an adjustable stop which cooperates with the hand fe-ed mechanism. In order that the wheel slide may be moved rapidly towards the work from a rearward position, without material attention on the part of the operator, the power feed mechanism is arranged to be releasablj7 connected to the cross feed screw, as by means of a clutch, and this clutch is actuated by a traveler mechanism which is mov able in timed relation with the cross feed screw so that the clutch may be disengaged when the wheel has reached a predetermined position, preferably at a point just before it contacts with the work piece orimmediately following an initial grinding cut. When the clutch has been disengaged the wheel may b e fed forward by hand until `the traveler mechanism has moved an arm or the like into the path of the adjustable stop of the cross feed mechanism, which serves-to stop further forward movement of the wheel.V

The invention further contemplatesa hand lever which is so connected to the powermech- -anism that the operator may manually control the application of the power to the feedingfmechanism in order to move the wheel in the desired direction vtowardv or from the work piece to a predetermined extent before being automatically disengaged and the cycle of operations repeated. The hand lever mechanism also serves to automatically keep the handV feed wheel disengaged from the cross feed mechanism so that the operator cannot manually turn the feed screw while it is being rotated by the power mechanism.

Referring more particularly to the drawings which illustrate the invention as applied to a cylindrical grinding machine of standard construction, the machine comprises the usual work table (not shown) traversable on'a V -way l2 constituting one of a pair of slide- -ways which is formed on the base 14 of the machine. In accordance with standard grinding practice, it is understood that the work piece will be suitably mounted on centers carried by the work table and will be rotated by suitable mechanism duringy the grinding operation. As shown in Fig. A2, a rotatable grinding wheel 2O is arranged to be fed toward and from the work piece to grind it to a predetermined size. For this purpose, the wheel Yis suitably mounted on a slide 22 which in turn is mounted on a'Vway 23 and a `flat way (not-shown) on a block 25 and is adapted to be moved by means of a half-nut 26 engaging a cross feed screw 27 arranged for movement by a feed mechanism of the type contemplated in the present invention.

Thefeed screw'mechanism is so constructed and arranged that it may be operatec either by hand or by power to'accomplish a feeding movement of the grinding wheel. ln the production grinding of crankshafts and thelike, it is particularly advantageous to feed the grindingk wheel rapidly toward the work and stop it at a position adjacent to the work surface whereupon it may be fed manually by the operator to precisely move it to the proper grinding position relative to the crank shoulders. At the completion of the grinding operation, the wheel is quickly removed by power from an operative engagement with the work in order that the table may be traversed to bring the next crankpin into alignment with the grinding wheel. To control the rate of grinding feed during the grinding operation a hand wheel is provided by which the operator may manually feed the grinding wheel into the wor at a proper rate toa position at which a stop ping device becomes effective and prevents any further forward movement of the wheel but allows it to grind out to the desired size. In order that the feed mechanism may be operated by power to bringthe wheel rapidly and quickly to a grinding position the feed screw 27 is provided with a gear 28 which meshes with a gear 29 fastened to one end of La rotatable shaft 30 which is mounted in suitable bearings Von a frame 32 secured to the front of the machine base 14. A bevel gear 35 -is mounted on the other end of the shaft 30fand meshes with a pair of

bevel gears

36 and 37 each of which is mounted for rotation on a shaft 38 which is rotatably mounted in the frame 32 and arranged longitudinally of the base. The outer end of the shaft 38 is provided with'a pulley 39 which is arranged to-be driven from any suitable source of power. The gears36 and 37 are preferably loosely'mounted on the shaft 38 and are so arranged that either one may be connected to the power shaft 38 to transmit power to the

gears

35, 29 and 28 torotate the feed screw in the desired direction.

To positively connect the

gears

36 and 37 to the power shaft 3S any one of the well known types of friction clutches may be utilized but rfor simplicity of illustration a double cone clutch member 4G is shown slidabl-y keyed to the shaft 38 by a key 4l and having a pair of frusto-conically shaped surfaces 42 and- 43 adapted to engage correspondingly

shaped driving apertures

45 and 46 within the

gears

36 and 37 respectively. It will be readily apparent fromthis construction that the operator may connect the clutch member 40 toV either one of the

gears

36 or 37 to rotate the feed screw 27 Yby power in the desired direction. This movable member 40 is provided with an annular groove 46 arranged for engagement by suitable actuating pins carried by a. yoked member 50 so that by swinging the member 50 about a suitable pivot point, the clutch member 40 may be moved into engagement with either one of the

driving apertures

45 or 46 to permit either one of the

gears

36 or 37 to rotate the feed screw. A hand lever 51 is pivotally mounted on "a stud 52 carried by a projection 53 extending from the frame 32 and it is provided with a pin 55 which is adapted to fit into an annular groove 56 formed in a spool-shaped member 57 secured to one end of a rod 58 which is slidably mounted in

suitable bearing brackets

59 and 60 attached to the kframe 32. The

other end of the rod 58 likewise is provided with a second spool-shaped' member .61 having an annular groove 62 which engages a pin 63 carried by a lever 64 which is fixedly mounted on a shaft 65 andkeyedthereto by a key 66. The shaft 65 is suitably journaled in a boss 67 on the front of the frame 32 and it is arranged to project within the 1nterior of the base. rlhe yoked member y is mounted on this inner projectingportion of the shaft and is suitably keyedthereto.

It will be readily apparent from this construction that any movement of the lever 51 toward the left by the operator to a position 51a, as viewed in Fig. 1, will impart corresponding movements to the rod 58, the 'lever 64 and the yoked member 50 to slidabl enf gage the clutch member 40 with the bevel Gear 36 whereby it may positively rotate the lfeed screw to produce a forward movement of the nut 26 attached to the slide 22 and thereby move the grinding wheel toward the work piece. Likewise, if the lever 51 is moved toward the right yto take the position 516, as viewed in Fig. 1, it will imp art corresponding movements to the rod 58, the lever 64, the yoked member 50 and the clutch member 40 in that direction to connect the gear 37 to the shaft 38 and thereby rotate the feed screw to rearwardly move the grinding wheel awa from the work piece. f-

In order that the clutch member 40 may be normally held in a neutral position and also that it may be returned to this position when the hand lever 51 is released by the operator, a mechanism is provided which comprises a pair of opposed springs so mounted that their respective spring pressures counteract each other toautomatically return the clutch member to a neutral position. To this end a spring 70 is loosely positioned on the rod 58 and interposed between the flange71 of the rod 58 and the face 72 on the bearing member 59. In a like manner, a second spring 75 is also loosely positioned on the rod 58 and interposed between the flange 71 and the face 76 on the bearing 60. It will thus be seen from this construction that any movement of the hand lever 51 in either one of these directions will compress one of the

springs

70 or 75 respectively and consequently it will be necessary for the operator to hold the lever 51 in its respective position to permit the power feed to move the grinding wheel through the desired distance toward or from the work. If at any time during this travel the operator releases his grasp on the lever 51 the resilient energy of the

spring

70 or 75 respectively, resulting from the releasing of the compressive force of that particular spring, will move the rod 58 sufficiently to slide the clutch member 40 into a neutral position. Y It can be seen that it will not be necessary for the operatorv to manually move the lever 51 to this neutral yposition to stop the feeding movement; he need only to release his grip on the lever so that it may spring back ofitself. l In order that the power mechanism may properly disengage the clutch at al predetermined point of the wheel travel, a traveler.

member is-provided which is arranged to be driven in timed relation with thepower shaft. To accomplish thisI purpose, a shaft 78 is mounted for rotation in suitable bearings in the frame 32 andcarries a gear 80 keyed to one end thereof which meshes with kthe gear 28 Vso that it may rotate when the feed screw is operatedby power. The other end of the shaft 78 is suitably. provided with an enlarged hub or` body portion 79 which is mounted for rotation in a front apron plate 81 integral with the frame 82 and carries a spiral pinion 83 loosely mounted for rotation thereon which meshes with another spiral gear 84 iXedly mounted on a flanged sleeve 85 rriiounted for rotation about a rotatable screw shaft 88 and supported for rotation within a bearing bracket 89. The shaft 88 extends through the bearing a releasable coupling attached thereto Vwhich is connectable with the gear 84. The other end of the shaft 88 is supported in'a bearing bracket 90 which is secured by suitable screws to the apron plate 81.` Thev gear 83 may be adjustably positioned with respect to the shaft 78 by means of a micrometer adjusting device 91 which comprises a worm 92 rotatably supported in a housing 93 integral with the gear 83 and mounted for rotation about a sleeve 94 so that it maybe revolved thereabout and locked in adjusted positions on a worm wheel 95which is keyed to the sleeve 94 by a key 96. Adjoining the hub 79 and integral therewith and the shaft 78 isa smallerhub member 77 on which the sleeve 94 is loosely'mounted for rotation thereon.

In order that the cross feed screw may be rotated manually-when the power is disengaged a handwheel 97 is provided which vcarries a huby 98 loosely mounted on the sleeve V94 and slidable therealong but in driving relationship therewith, such as by means of a key and keyway suitably located in the parts. The hub 98 is provided with clutch teeth 99 which are suitably formed thereon for enf gagement with a set of similar teeth 100 on the worm wheel 95.

To render the driving connection between gear 88 and the shaft 78 positively operative by power, ka suitable clutch mechanism of the spring pressed plunger type may be utilized but in the preferred construction it may comprise a sleeve member 101 which is rigidly fastened on a reduced extension 102 vof the shaft 78 by a key 103 and is arranged for sliding movement therealong. The sleeve 101 bracket 89 and carriesA means of a key 86. This sleeve 85 is isprovided lwith'arreduced end portion 104 which `:is adapted to Vfit within the .-sleeve .9.4 and its body portion :isfsuitablywshaped to providea hub 105 to supportthe hand .wheel 97.1and which -riay rotate with thehub :98. The inner vface ofthe hub i is provided with Lteeth 106 which .suitably engage .other teeth 107 .extendingzfrom the frontend ofithe sleeve94. Toholdithe teeth 106 and v107 .in

.. rproperfdriving engagement-asprin'g 109 is loosely fitted into va .cylindrical `.cavity 110 within'tliefsleeve '101 `and positioned `on lthe extensionl102soas to be interposed .between theffiange 112 on the extension :102 and the inside face 113v ofthe cavity 110. The hub105 extends. outwardly vfrom'the hand wheel `hub 98 and is `-shaped to iformva stepped collar lwhich serves to hold the hand wheel 97 iin place on. thesleeve 194and also provide fa means' forrdisengagingtheteeth 106; and 107. In .order -to properly @connect the shaft .f 88 toit-he power feed, a suitable spring pressed coupling .mechanism is utilized -and as illustrated it comprises aiianged sleeve 115 4which isslidably keyed by means of;a vkey 116 to the-extension ofzthe shaft S8 which overhangs the bearingbrac-ket89 and itL-is'providedat one'end with a largeflange 118 which.is=ar rangedtoibe held. against'the correspondinglyshaped flange 119 formedon` the sleeved85 and 1 connected .in driving :relation 1 therewith by means ofia V pin 120. A spring 121 `arranged within arrecess 122.1of the sleeve 1.115 and'interposed zbetween thebottom face 123 oiff'therecess andthe retaining nuts '125 serves to holdthelflanges 1118and 1119 in the proper driving engagement. .A flange 126 iis .provided on'the open endiofthe sleeve .1.15 -for the purpose `offmanual adjustment. j

To ypositively disconnect 'the power :feed mechanism, means are provided which automatically become effective when ithe wheel slide reaches Vaipredetermined point. Further movement ofthe slide willthrow a Astop into the rpathof a movable abutment connected .tothe cross feed zmechanism. so as :to prevent 'further forward .feeding of the grinding wheel :by =`h'and. To. accomplish this, :a .nonerotatabl'e nutais longitudinally moved 4by -a screw gearedto-t-hecross feed screw and adapted tofengage afinger which is arranged to'bemovedv into and out of Yits path fof movement to'disconnect the power clutch andithen after a predetermined number .of revolutions ofthe screw `by hand to engage a stop lever and inoveit intothe path o'f -an abutment associated with the hand wheel 4which isemp'loyed to rotatefthe'screw. As shown in the present-embodiment Vof the invention, a non-rotatablennt 127 is arranged for=travel .longitudinally alongl the screw 88 and .-.itiis heldfagainst'rotation against afia't guidcway 128sby means of aV suitable flat portion 129 provided onthe-si de portion of the mit 127. c

isz-2h91 A In order that the clutch 40 may be'thrown automatically a lever 130 having a hub portion 131 is pivotally mounted ony a. stud 132 attached to the front plate 81. A pair of

spacediingers

133 and 134 are mounted in a staggered relationship on the outer surface of the hub 131 and are arranged for movement into and out of the path of-travel of the nut 127 by means of a link member 135 pivotally connecting the lever 130 with thel lever 64. In order that this connection may be` adj usted sothat the nut 127 will strike the fingers 133-and 134 respectively at the proper position, adjustable contact vmembers 137 and 13 are provided 'which' are mounted on the depending

lugs

139 and 140 respectively, formed on the nut 127. From this. construction vitlwillvvbe readily apparent that when the Vnut 127 is moved in a forward direction the member 138 will contact with the linger 133to swing the levers 1307 64 and 51 to a neutral position, as shown in Fig. 1, thus disconnecting the power feed.

To-positively stop the cross feed mechanism atfa predetermined point after a predetermined number of revolutions of the screw'by the hand wheel7 a stop lever 141 is provided having a relatively long arm 142 and a short arm 143'which is forked to straddle the screw 88,'th'e-lever being pivoted on a. stud 144 on the front plate 81.- The lever 141is prefere` blyheld in an inoperative-position, as shown in Fig. '1, by means of a spring' 145 which is positioned loosely on the screw 88 and interposed between the cheek 146 of the bearing bracket -90 and the side face 147 of the arm 143 so as to move the lever arm 142 to an inoperative position as shown in dotted lines in Fig.1\andfout of the path of a movable abutment 148 carried by the arm 149 attached to the housing 93.

ln'order that the manual feed mechanism may 'be' automatically connected when the power is disengaged a lever 150, fixed-on a shaft 152'bya key 153,*carries a T-shaped member 154 having a pair of

flat portions

155 and 156 which are arranged on each side of theT respectively and ,separated by a V- shaped groove 158 for the reception of a pin 159 projecting from the hand lever 51.

Thecontact member 154 and the pin 159 are held in engagement at all times by a spring'160 .which is suitably fastened to the bracket'60 and an arm 161 fixed on the sha 152. The shaft 152 is rotatably mounted in

suitable bearing members

163 and 164 carried by the

brackets

59 and 60 respectively, and ithas ayoked member 165 which is securely fastened to the other end thereof by means of a suitable key or the like. the yoked member 165 move the hand wheel 97 into and out of engagement with the feed screw mechanism when the hand lever 51 is ina neutralposition, it is provided with 1n order that L suitable pins'167 and '168 which t'into an 'fifi annular groove 169 formed in the hub 98 of the hand Wheel 97. It can be seen that by swinging the yoked member 165 about its pivot the hand wheel 9,7 will'slide longitudinally along the sleeve 94 to engage the

clutch teeth

99 and 100 and operatively connect it with the housing 93. Y

.In setting up the machine for aV given piece of work, the operator-must make certain adjustments of the parts. To do this the-work is first ground to the required size by manually feeding the wheel-into the workpiece and noting the size readings as indicated by a dial gauge. When the work has reached the correct size, the machine is stopped and with thegrinding wheel still in contact with the finished work piece the stop 142 is moved, by the operator, downwardly into the path of travel of the abutment 148 and against the pressure of the spring 145. The sleeve 101 is disengaged fromthe sleeve 194 thereby n leaving the housing93 and the spiral gear 83 free to be turned about the shaft 7 8 by the hand wheel 97 so that the abutment 148 may be moved into engagement with theend of the stop 142, after whichl the

sleevesk

94 and 101 are reengaged. When the above adjustments have been made and with the .stop 142 held in this position against the abutment 148 by the operator, the flanges118 and 119 are disengaged and thepin 120 removed from driving relation therewith, so .that the screw 88 may be freely rotated manuallyby the flange 126 to move the traveler` 127 longitudinally therealong until `it contacts with the arm 143forming a part of the. stop 142,

whereupon the flanges 118 and'119 and the pin 120 are reengaged. n,

. Following this, the next adjustmentto be applied is to the power disengaging stops for the forward and rearward movement of` the grinding wheel. To accomplish this, the hand lever 51 is moved vby the operator to a position 51a, as shown in dotted outline in Fig. V1, thereby applying power to feed the grinding wheel in a forward direction towards the work until it nearlyV contacts with the work piece. At this point the operator releases his grasp on the hand lever 51 and it immediately springs backV to a neutral position as shown in fulllines in Fig. 1 thereby disconnecting the power from the feed screw and stopping the wheel.V The power is turned od and thelever 51 again moved to take the former position 51a!l thereby moving the finger 133 to avertical position by means of the link vmembers'130, 135 and 64, and while in this position, the le/g 138 is moved into contact with it.V The lever 51 is allowed to spring back to its neutral position thereby moving the linger 133 from its vertical position and the Yparts take the positions as shown in Fig. 1, a-fter which the dog 138 is advanced a fewadditional turns in order thatit will contact with the vfinger A 133 and start it moving slightly in advance of the stopping position of the wheel. Next, the wheel is moved to its maximum rearward position and a similar adjustment is made to the dog 137 and the finger 134 `with the lever 51 occupying` a corresponding position 'ments away from the stop 142 in order that the abutment may move a short distance to compensate for the wheel wear in the' finished work size, and also to automatically relocate the vtraveler with respect to the wheel slide to providea correction for wheel wear `in the stopping mechanismdueto the fact that the micrometer mechanism serves as the driving medium. These dog and stop adjustments, when once made, are kept fixed with the exception of the small increment adjustments to compensate for wheel wear.

When anew wheel is installed it will be necessary for all the adjustments to be changed and the same adjusting processes gone through again vwith the exception of the adjustment of the

stops

137 and 138. rlhe positions of these stops on the traveler 127 is dependent upon the work diameter and independent of the wheel diameter so .that when once adjusted their relationship ,will be fixed with respect to the traveler and needY not bechanged except when the work diameter is changed. With this device, the one adjustment for wheel wear in the finished Vsize stop automatically compensates for wheel wear for the traveler. 'i

As heretofore stated, this mechanism is primarily designed vto be used in a machine for thegrinding of crankshafts or for doing special types of work in which the mechanism is set up for one particular size of work piece and the adjustments are kept fixed for that particular type of work, being changed onlywhen the machine or apparal tus is changed for another character of work. lHence, forvwork of this sort the only adjustments which are necessary are those which must be made at the time of wheel replacements, namely the setting of the finishedr size stop and the traveler stop relative to ,the feed screw.`

The operation of the mechanism is readily apparent from the foregoing disclosure.

When the operator moves the hand lever 51 spring 75, this movement serves to engage the clutch ymember 40 to cause an inward feeding movement of the grinding wheel by power f toward the work and to simultaneouslycause the traveler nut 127 to move 'longitudinally along' the screw shaft 88 until thev contact member 138 Ythereon strikes the inger 133, which has been thrown into its path by the movement of the lever l. The forward feeding movement of the grinding wheel by power'continues while the nut 12? movesfurther along the screw 88, towards the left, during Y 40, the rod 58 which is connected with the le'- ver'51,moves the lever 51 from the dotted position 51a, as shown in Fig. 1, toits neutral position, as indicated in full lines in Fig. 1. 'lhislatter movement of the lever 51 serves to'move the pin 159 along the flat way 155 un'- til it drops into the V-groove 158 in the-mem*- ber 154, therebysliding the hand wheel 97 into operative engagement with the wheel feeding mechanism to permit t Le operatorto vfeed the wheel manually during the grinding operation. Y Y

After the work piece has been ground toltlie desired size, the hand lever 51 may be mc-ved by the operator towards the right, as viewed in Fig. 1, and there heldv by Vhim in a position ''ll'a-Uainst the Yrassure of the snrinerv 70 this e P e a movement serving to engage the clutchl'mem- 'ber LO'to thereby remove the grindingwheel bypower rapidly from the worlr and t'o a rearwardj position. The rearward movement of the grinding wheel'continues until the corrtact member 13'? strikes the linger 134i, which projects in `its path, and swings the'l'ever 130 `and its connected mechanism towards the left tol overcome the holding pressure applied to the lever 51 by the operator and: to disen- 'gage the power clutch. It will be apparent that during the pow-er operation of the feed screw, any movement of the handA lever 51'yto either one of the positions 51a or 515 will slide 'the pin 159 along the flat ways 155, o'r 1156 respectively and thereby rock the member 154 Vaway from the plate 81 with thev flat faces 5155' or 156 being held into contact with the pin 159 byy the spring 150. rlhis movement is communicated to the yoked member 165' to move it a corresponding amount in order to prevent the hand wheel 97 from being thrown into engagement with the worm wheel 95 'dur- 'ing' 'the power infeed. rllhe contact `member il, 87a, liet screw 88.-' until it nontactswthif the@ arm-143; The contactmember 138 isinterp'osed by; this movement into theipath ofthe finger 1331 and thereafter preventsi'tlie clutch Ofrom` being engaged to'icause'the-wheelslide to be moved furthe'rb'y pewerin=ithe same direction while AL. cross feed mechanism for a'. grinding machine slidecomprisinga manually operable feed screwk cen-nected'lto the -slide,apower mechanismv ccn'ne'ctibl'etoy rotate the feed screw, means including-a` Contact member to disconnect saidl power mechanism from the screw, a stop mechanismetastop the slide at a `predetermined position', and a traveler movable Y inl timed relation with the feed screw-'te actuate successively saidcontact member and said stcpfmechanismf.

2. A- cross feed mechanism'` for a grinding machine slide com-prisi'ng4 a manually oper'- ableV`V feed screw connected to the slide', a. power mechanism, a1 'clutch mechanisml includinga contact-member for connecting the power mechanism 'to-thescrew, mechanisminb cluding an adjustable. stop te stop the slide at a predetermined? point, a travelerv movable in timed relation with :the feed screw toactu- -atelsaidfcontact member'and said'- stop mechanism successively toL throw the clutch and thereafter to stop the wheelslide, andmeans for 'adjusting the position ofthe traveler relative tcsaidstop' mechanism.

3'; 'crcssfe'ed mechanism fora grinding machine' slidecomprising a lma'nua'lflyv oper'- able cnoss feed screw'connected to move the slide, val power mechanism to rotate the feed screw, meansiincluding acontact :member for disconnectingsaid mechanism from the feed screwfwhen theV sl'ide -lias'rea'chedj a' predetermined point, adjustable mechanism including: ja Y positive stop: to' lim-it thev Vsubsequent manual Vmovement lci? the slide7 a traveler movable-in ,timed relation with the feed screw "to actuate successively' said contact member and said stop-` mechanism, 'andmeans for simultaneouslyadjusting the npositions of said sto'pan'dsaid traveler with respect to the feed sclrewltol compensate for wheelY wear.

` 4. Across feed .mechanism vfora:'grinding wheel vslide comprising ka manually operable feed screw' connectedto the slide, a power mechanism, a clutch to connect the power mechanism'to rotatefthe feed screw in either direction, means including a contact member to operate `the clutch 'and disconnect said v-p'ower mechanism fromtlie screw'when the slide'hasreached any'predeterm-ined position,

and a traveler movable in timed relation with the feed screw to actua-te said Contact member and disengage the clutch, and thereafter prevent the power mechanism from being oonnected to move the Wheel slide further in the same direction While the slide is being moved manually.

Signed at Worcester, Mass., this 13th day o1? March, 1930.

GEORGE H. SMITH.