US2375340A - Machine for grinding metal - Google Patents

Description

y 1945. E. BANNISTER 7 2,375,340

' MACHINE "FOR GRINDING METAL Filed Oct. 28, 1942 10 Sheets-Sheet l Invefitor 4 By 'r. i

1945. E. BANNISTER MACHINE FOR GRINDING METAL 1 0 Sheets-Sheet 2 Filed Oct. 28, 1942 I y 1945. E. BANNlSTER 2,375,340-

MACHINE FOR GRINDING METAL Filed Oct. 28, 1942- 10 SheetsSheet 3 Inventor 43 4 75 May 8, 1945 E. BANNISTER MACHINE FOR GRINDING METAL 1O Sheets-Sheet 4 Filed 001;. 28, 1942 I Ihvqnlor I Man /sf mrwt y 1945. E. BANNISTER MACHINE FOR GRINDING METAL Fild Oct. 2 8, 1942 10 Sh'eets -Sheet 5 Inventor .MI/Wffib- Atlorng s ,E. BANNISTER MACHINE FOR GRINDING METAL.

10 Sheets-Skeet 6 Filed Oct. 28, 1942 lLl In ventbr Attorney;

y 19.45. E. BANNISTER MACHINE FOR GRINDING METAL 1o Sheets-Shet 7 Filed Oct. 28, 1942 In veri'tor dwvnsrag,

Atlornea May 8, 1945.

E. BANNISTER MACHINE FOR GRINDING METAL 1 Filed Oct. 28, 1942 10 Sheets-Sheet 8 In ventbr ifimvmsrea Attorney E. BANNISTER MACHINE FOR GRINDING METAL May 8, 1945.

Filed Oct. 28, 1942 10 Shets-Sheet 9 Attorner May 8, 1945.

E. BANNISTER MACHINE FOR GRINDING METAL Filed 001;. 28, 1942 10 Sheets-Sheet 1o In ventr l-dl/YM/SIZL I 5 Attorney different metals.

Patented May 8, 1945 UNITED STATES PATENT oFncs MACHINE For. GRINDING METAL Edgar Bannister, London, England, assignor to D. Gilson and Company Limited, London, England, a company of Great Britain Appeal-associates 28,1942, Serial No. 463,682

In Great Britain Novemberl29, 1941 20 Claims.

The invention relates to machines for grinding metal surfaces, and has particular reference to the grinding of the lands ofscrew dies of the so: called button type.

In finishing screw dies, particularly those made for precision work, it is necessary to grind accurately the leading face of each land. In order to produce the best cutting edge, the angle of the leading face to the radial line passin through the cutting edge mustbeqaccurately defined, although it may be different-for dies for cutting It is also important that the leading faces of the different lands shall be equally spaced angularly around the die, that is to say in thecase of a 4 -land die, for example, the leadingfedges must be accurately spaced 90? apart; furthermore, of course, the leading-edges must all be equally spaced from the centre of the die. These latter two requirements are necessary if all the lands are to do the same amount of work and screw threadsof the accuracy necessary in precision work are to becut For this finalfinishing by grinding, it is fairly usual nowadays to use a small grinding wheel ofa suitable abrasive material which has to be of "small diamete r in relation to its length sothat it takes the shapeo'f a pencil which is rotated accurately about its axis at-very high speed A convenient form of such a grindingvwheel is what is called an air-driven pencil sinceit is justed to fix the amount of feed. Then the actual shape of the leadingedge of each land of the die is determined by mounting the grinding pencil on a pantograph mechanism furnished with a stylus which the operator keeps in contact with an enlarged copyof the desired leading face.

For convenience it can bearranged that the op-,

number of lands are often produced. Therefore,

when the leading face of one land has been gr und it is necessary to be able to rotate the die in its holder accurately through the desired angle-which in the case of a four-land die'is an angle of 90f -s o that the leading face of the next land can be shaped accurately to the same shape as the first land but at an angle around the die which is exactly 90 in the example of afourland die with respect to the leading face of the first land. To facilitate this procedure, the die holder isprovided with a registering device which rotated at high speed by comp ressedfair actingon'whatamo'untsto a small air turbine, the rotor of which is on therear end of the grinder spindle. If the die tobe finished is mounted in aholder andthe grinding pencil is on a carriage or sup: port which is moved by hand by the operator while the pencil can be ,reciprocated in 'the direction of its axis, .it is clear that the accuracy of the finished job depends almost entirely on the skill of the operator. i

- The object of the present invention is to produce, a precisoni machine which can be. used by an unskilled .or' 'relatively unskilled operator and yetproduces accurately. in everydie the necessary conditions which have been set out above.

According to the .present' invention, such a amount about its axis and the totalamount of l that feed can be predetermined since the rotation is effected by the operator 'turningawheel it is brought up against a stop whichis' pre-ador handle until the handle or apartintegral with r can hold it accurately in anumber of positions spaced apartby thenecessary angle depending upon the number of lands. The registering device may consist of the appropriate number of recesses in the periphery of the holder engaged by a pivoted tooth carried on the holderalthough, of course, the converse arrangement might be employed. Between the feed handle which may rotate'the die holder through worm gearing, and the die holder itself, a one-way clutch which may conveniently be a roller clutch without backlash,

is provided. Then, as the" cut is applied by rotating the die holder, owing to the shape of the recess and the engaging'tooth, the latter is gradually forced out of the recess until it rides on I the periphery' of theholder, the. drive being through the aforesaid one-way clutch. Then, by

rotatingthe die holder in the same direction so because the die holder is held by the; tooth and recess. The procedure is then repeated until all the lands have been similarly. accurately ground.

7 :In such a machine the grinding pencil, of course, is subject to slight wear and after. a time the surface'tends to become glazed. It is necessary to be able todress the grinding pencil, and the present invention provides *for that dressing while compensatingior the slightly reduced diameter of thegrinding pencil without loss of accuracy in the grinding. For that pur' pose; the die holder is mounted on. a crosse'slide with an operating wheel properlyindexed which enables the die holder to be moved slightly acrossv the machine.

The dressing diamond is' provided merely with a holder the body of which can be set in the machine in the die l-ic'ilder in sueh a position that when the grinding pencil is centred in the machine, which can be efiecte'd by serting a locking taper pinin the pantograph r'nechanism, the pencil, before it has been' reduced in diameter, takes up a central position in a central bore inthe dresser body and can be rotated therein. The diamondvcarrier is set radially thebody so-that it can be broughtaccurately up to the surface of the grinding pencil for the dressing feed. For that purpose, a pm of the-same diameter as the grinding pencil is introduced through'a bore at the top which it fits accurately and the diamond is set accurately just in contact with the pin Whichisthen withdrawn. The grinding pencil is then brought up into the central position and jthe-cross-slide referred to is advanced the necessary amount and line III-III in Figure 2, Figure 3 again illustrating the left-hand side of the machine, and Figure 3a. the right-hand side of the machine;

Figure 4 is an elevation of the machine seen from the right of Figure 3, the view being shown partly in section on the line lv lv in Figure 3a;

Figure 5, is a perspective view showing the main parts of the pantograph linkage employed; Figure 6 is a vertical section showing the main pivots of the pantograph;

i Figure 7 is a central vertical section of the die I holder and its driving mechanism, and also showthe diamond takes a slight out on the periphery of the grinding pencily If no furtherprovisions were mad and the grindingof the die were proceeded with; it is obvious because of the reduced diameter of thegrinding pencil that the next cut would be slightly less deepthari the immediately preceding out before the grinding pencil were dressed. 1 This is corrected or compensated-for, however, by leaving the die holder in the slightly adjusted position it has been given by means of the cross feed so that in effect the die has now;

beenslightly placed out of'centrerelative to its previous position by an amount equal'to the cut.

taken off the surface of the grinding pencil.

adjustment of the die, the next land of the die will be cut in exactly-the same way as the pace-- ceding land is cut. j I Q *1 K For convenience in such a machine, the grind- Thus; when grinding next proceeds, owing to this shaft 1 to the driven sleeve 6 so that the machine ing pencil is not given a vertical reciprocation atell, but'when the jp'antograph is unlocked,

' it can only move in a horizontal plane inaccordanc ewith the shape of the'pantographcopypiece. The die holder, howevenis mounted on a carrier which includes the worm mechanism for producing the feeding cut, and this carrier is mounted was to be capable of vertical reciprocation under" the action of camsona cam shaft which extends from right to left across the machine below the carrier;

derstood and readily carried into effect, a ma- Ifo'rgrinding a four-land button die will now be described byway of examr'il with reference :to the accompanyingdrawings', in'which: "Figure 1 is aperspective View of the'outside of-the complete machine Figures Zand 2a. show a plan of the machine,

Figure 2 depicting the left-hand side,--'and-Figure zaithe. right-hand side of the machine Figures 3 and 3a show a vertical section on the.

mg t e inding pen l;

Figure 8 is. a horizontal section on VIII-VIII in Figure 7;

Figure 9 is an elevation ofa detail seen from the front of the machine in the direction ofthe row X in Figure 4; V s

Figure 10 is an elevation, with the lower part in section, f the compressed air motor for the grinding pencil; I I 1 Figure 11 is a diagram to an enlarged scale of a die to be ground;

Referring first ofall to Figures 1 to 4 the ma: chineshown as aniexample is a small bench inachihe housed in a casting l and driven by a small'electric motor 2,1who s'e shaft 3 runs from the back of the machine towards the front at'the right-hand side of the machine; as best seen in Figure'2a. The motor 2'' drives a worm 4 and a worm wheel 5,-which latter-is carried by a sleeve 6 which is journalled to turn about a cam shaft! of the machine which runs transversely across the machine from the right-hand side. The

movable member 8; ofa dog clutch iskeyedjtothe I shaft 1 and; can be shifted to the right in Figure Sate clutcnthe cam shaft 1; to a hand wheel 9;

The member 8 also has dog teeth its opposite r or left-hand side in Fi u e 3wwhich, when the membergais moved to th left," clutches thecam can be turned slowly by hand by the hand wheel 9 or can be power driven. Theclutch member is actuated by a control lever in the'form" ef -a joystick [Wmounted for transverse'movement from left to right of the machine, and for foreand-aft movement vfrom back 1 to, front of the machine. "During the transverse moveme'nt .it

' has three definite positionslocated by spring- "In order that the invention may be eleafly chine in accordance-with the invention designed pressed balls H (Figure 4); When th joystick I0 is moved tothe left intol the' position Illa shown in Figure 21;, it rocks a fork l2 to cause the clutch member 8- to engage the sleeve 6. jWhen thejoysticlg is in the middle'positiomthe clutch member 8- is disconnected, and when it is moved to the right hand positionshewn; atiflb infigure 2c, the clutch member 8 is connected to the hand wheel 9. During thefore-and-aftmom m 'o eiqv i k. Uta va v 1 c nt l neth sumflyv f presse air o t e rindi g w e l mechanism isoperated. Compressed air: issup pliedithrough a pipe: Hand the valve l-3 controls its passage'to a flexible pipe iii-which is connected be'described later. The lever lo ispivoted at its to the air motor for the grinding pencil, as will the line the l-gr-inding pencil shown in positionin the I lower end at 15, and when in the full lin position shown at Ill in Figure 4,the valve I3 is pushed backward from the position shown in Figure 2a to shut off the connection between the pipes l4 and 15. When the joystick is turned intothe position shown indotted lines at in Figure 4, the valve 13 is moved into the position shown in Figure 2a to allow the supply of compressedair to pass to the machine through the pipe 15. The

lever moves between the lugs2-l6 of its pivot bracket ,and these lugs are furnished-with pips its ,fore-and-aft positions 2|! for indexing it in I00, 1..

The grinding wheel mechanism seen Figure 3a but shown in detail in Figure l 0,-compris'es a casing ll mounted on and extending...'upwards, from a bracket Ila carried. on a horizontal link-1'8 of the pantograph linkage. assemblycan beadjusted from back to front of the machine on a slide .19 on. the link I8v and is locked in the adjusted positionby means of a setscrew 20. The compressed air pipe l5 is connected to an inlet nipple 2i communicating with a passage 22 in the base 23 of the grinding'wheel mechanism. Th passage 22 is continued as a nozzle 24 in a plate 25 so that jets-of air are injected into the blades of a bladed wheel-'26. The, .wheel 26 is fixed: to'the lower end of -the spindl 21 of the grinding wheel or'pencil 28 and which is a cylindrical pencil of v.emery or other abrasive composition. The spindle" 21 is journalled in the casing l1 and the'air escaping from the wheel 26 passes upwardly through the casing H, as indicated by the arrows 29 in Figure 10,- and therefore serves the purpose of cooling the bear ings of the spindle 2'! and also of blowing'away any fine dust removed from the die under treatment by the grinding pencil 28. i

The pantograph linkage is best seen in Figures 2, 2a, 3, 3a, 5 and 6. It consists of a parallelogram linkage consistingof two pairs of parallel links I8, 30, 3|, 32, hinged together at-thecorners.

As already stated, the grinding wheel-mechanism; is mounted on the linkl8 which is hinged to the link 3| about a pivot 33'. I This pivot; asshowndn Figure 6, isoffset from another-pi'vot-34 which is the main fulcrum of the-mechanism and is'set-in the bottom plate 35 came machine The link 30 is steadied by means of-a pair of auxiliary links The. grinding wheel The tracing point 42 is arranged to be moved over a small .table 52 secured tothe casting of the machine and arranged to carry a copy-piece or pattern 53 which has a rib 54 which bears the same profil as the faces of the die to be ground. When the pantograph linkage is shifted so that t the grinding pen'cil28 takes up a central position within the die holder, the pantograph linkage can be lockediin' that position by the insertion ofa tapered plug 55 into holes in the main casting I and passing through a hole in the rod 44,-as seen in Figures 2 and 3. The grinding pencil 28 is only able to move in a horizontal plane under control of the tracing point 42 of the pantograph mechanism and is not mounted for up and down movement in a vertic'al plane;

on the other hand, the die'holder shown in' detail in Figures 7 and 8 is mounted to slide up and down, being fixed to two supporting pillars 56, 51 whose axes lie on the transverse centre line of the die holder, as can be seen in Figure 2a, and

6' a front central steadying column .38v whichis merely guided in guides 59 in the framework casting of the machine so as to prevent any rocking of the die holder'when the latter is raised or low ered; The die holder is raised and lowered'by ,means of the pillars and 5'! which are camoperated from the cam shaft 1; This mechanism is seen best in Figures 3a and 4. Each of the pillars 56,51 has at the lower end an'adjustable tapioet-like member 59, Bil, adjustable by means. 7

of screws '61-, 62 and locked in theadiusted position by lock nuts t3, 64. The tappets"59, -60 have large heads which rest on operating rollers 65,55, as best seen in Figure 4. Each'ofthese rollers is carried atthe free end of an arm 6l'pivoted towards the back of themac'hine'at 58and each as, 3 1, the link 36 being pivoted at-38=to=the pantograph link and at 39 to the 31, the latter being pivoted to the bottom plate at the point 40. The upper link I8 is also steadied in a simi lar way by a pairof links not shown in Figure-5, but one of which appears at-4l in Figure 3a,- and turns about a vertical pivot fixed to the casingfiot the machine, and alsopivoted toa second link which in its. turn is pivoted to the-bracket -l1 asecured to the pantograph link I 8.- The stylus or tracing point 42 is carried-in a head 43"which can .be adjusted along arod 44 andsecuredin position by alocking screw 45:- The rod 44 is rigidly fixed by a bracket 46 in line'with thecentreofthe link 32. It will, therefore, be seen that'by moving the tracing point 42,- the linkage I8-, 30-;31, 32, turns freely about the main fulcrum pivot 34, an'dfthe different links can turnabout the pivotswhich formthe hinges between each pair of links; The,

equivalent pantograph'mech anism is indicated by the three lines4'l; 48 and 49 in'Figuresi2 and 2a.

v The intersecting point 50- between thelines 41 and 48 represents the positionof the axis of the main fulcrum 34 of the pantogr'aph'llnkag 'e. The axis of the pencil -28is located at the point-i5! in the cntrelineof'the link '18. already men-f the assembly can be moved slightly from right to The sliding surfaces are of the arms at its mid-length has a rolleror cam' follower 69 which restson the respective cam '10 on the cam shaft 1. The cams 1B are of the same shape and operate in unison to lift the arms 61 together so that the rollers 65 lift the pillars .56,

5! and'with them the whole die holder assembly. The latter'descends under its own weight'or under spring tension which retains the tappets 59, B0 in contact with the rollers 65, 66. v

Thewhole of the die holder assembly, including the pillars.56, 51, the guides H, I2 in which they slide, and the steadying pillar or column 58,

and the guide 59 in which it slides, is mounted on a slide on the machine bed by means of which left of the machine. seen at 13 in Figure 4, and the usual packing gibs are shown at 14. The sliding movement is effected by a screw-threaded spindle "15 carrying an index wheel 15, the latter bearing against a surface 11 on the main frame casting l, and the threaded spindle'l5 engaging a-threaded nut member 18 which is rigid with the dieholder assembly. Ac-

cordingly, by rotating the hand wheel 16, the

Whole or the assembly is moved tothe right or l'eft on the sliding surfaces 13 by apredetermined; amount. A locking screw for this slide is provided at 19 and this naturally has to be slackened back before the die holder assembly can, be moved.

Th die b ld r s m l s et in o a ze o De tion when the grinding pencil-is new and hasnot has been movedfore-and-aft to admit the supply of compressed air to the grinding pencil'assembly as already indicated, andthe cam shaft I of the machine has been clutched to the driving motor by moving the control lever III into the left-hand,

position Illa in Figure 2a, with the result that the grinding pencil 28 is rapidly rotated and the die holder 80 carrying the die 82 is reciprocated up and down so that grinding on the leading face of the land of the die goes on. This process is con tinued until the stop surface 96 on the arm 95 (Figure 9) reaches the predetermined stop member I00, at which time it is known without any exercise of skill on the part of the operator that the grinding out has been taken to the desired depth and exactly the correct amount of metal between the lines I I and II I in Figures 11 and 12 has been removed.

It will be observed thatfone face of each of the recesses I02 is shown in Figure 8 to be more inclined'than the other so'that as the di 82 is rotated counterclockwise in Figure8 and the feed goes on, the tooth I04 is gradually forced out of the recess I02 with which it is engaging, and

outwards into the position shown at'III Ia in Figure8 when it comes to 'r'eston the cylindrical "clutch rollers 81 slip and'th'edie is not rotated.

In the example illustrated of a four-land diefthe notch I02a now engaged by the toothIM is exfinally the point of the tooth I04 has beenlrocked actly at 90 to the notch shown engaged'by the tooth I in Figure 8, so that themachin'e is ready for a similar grinding cut on the next land of the die, and indeed the cut is made exactly at 90 fromthat made on the first land.-' It is made of exactly the same shape due to'the use of the pattom 54 and to exactly the'same depth due to the permitted traverse of the crank feed'handle 94. Therefore, when allfour lands have been ground,

is spaced exactly at 90 from 'the'corresponding their leading faces are ground to exactly the same I point 'on the next land so that an entirely uniform and satisfactory flnishis produced on the die.

In the drawings, the die is prevented from moving in the holder 80 from theshelf '8I by a tubular clamping member "I I5 which can be inserted into the holder'on top'of the die 82. It

hasa number of peripheral projections I I6 which can enter the die holder through slots III (Figure 2a), and on rotating the clamping member- II5 by handles II 8, the projections II6 ,,enter cam grooves H9 with inclined upper surfaces so that the clamping, member H5 is firmly pressed down on the top of the die 82.\

After a certain number of operations, the

grinding. pencil '28 has become. glazed and its surface needs, redressing. Thenfthe die 82 is removed from the holder 80 and a wheel dresser is inserted in its place. This is illustrated in Figures 13 to 15, in which the same references have been used for corresponding part as in Figures '7 and 8. The wheel dresser consistsof a body I20 of thesame shape externally as a die and with the wheel dressing tool I20 which is formed with an upwardly extending boss I26 centrally bored to receive the gaugel25 as shown in Figure 14. The point I22 of the diamond is just brought up to the'outer surface of the stem I21 of the gauge I26 and then the diamond is locked in that position-by aset-screw I24. The gauge I25 is re-v moved and the wheel dresser IZO placed in'th'e die holder 80 and clamped intov position by the clamping sleeve I I5. Then the grinding pencil is set'into rotation by admitting the compressed air supply and the machine set into operation. The grinding pencil 28 is moved-slowly to the left in Figures 13 and 15 by moving the whole of the die holder assembly to the left byu nlock ing the. screw I9 and operating the indexing wheel I6 so that the whole of the die holder as sembly moves on the slide surfacesIB.

During this sliding movement the tappet heads 59, remain in engagement with the rollers 65, 66 since the tappet heads are made large enough to ensure this.

When the grinding pencil 28 is 'sufiiciently dressed, the wheel dresser is" removed from the die holder and the transverse slide is left in the position which it has reached and is locked in that position by tightening the screw I9. The refsult is that when the die or a fresh die is placed in the die holder, it is slightly displaced in position'from that which a die occupied before the grinding pencil was dressed by an amount equal to thecut taken off the wheel in the dressing operation by the diamond I22. Therefore, when grinding of the. die is resumed or a fresh die is ground, the grinding pencil 28, although slightly reduced in diameter, takes exactl the samecut -upon'operating the crank handle 94 whichjit would have taken if it had not been reduced in diameter and the'die holder had not been moved transversely. I

The invention has been illustrated and described with, particular reference to the grinding and finishing of a button type screw die with four lands spaced at 90 apart,lout it is clear that the machine by use of a suitable 'worklholder, can beused for grinding any metal partsthat require asimilar finish. Thus, for examplelthe invention is applicable to the grinding of thein+ ternal teeth of annular gears.

'Iclaimz' g 1. In a machine for grinding the lands of button screw dies, the combination of a dieholder mounted for rotation about the axis of a die'carried in said die holder, a spindle journalled to rotate about an axis parallel to that of said die holder, 'a grinding tool mounted on said spindle,

a support carrying said spindle for rotation about said axis, power means operatively connected handle, stop members mounted in the path of said handle for: limiting the movement of same in both directions, and gearing connecting said feed handle tosaid die, holder to rotate the ;-latthe -cut.-

.ter about the axis of the dieto produce ,tingufeedduring'grinding.' a

32; In a machine for grinding the t me ton screw dies, the combination of;adie holder .mounted for rotation about the axis or a die ear; tried in said die holder, aspindlejournalled to tate about an axis parallel to thatof said die,

holder, ;power means :for rotatin'g said spindle, a

produce the cutting feed during grinding, 1 3. 'In a machine for grinding the lands 'ofbut-1 ton screw dies, theflcombination of a die holder: mounted for rotation about'the axis ofia die oar-1 ried in said die' holder, a spindle journalled to rotate about an axis parallelto that of said die holder, power means for rotating said-spindle, a; a. pantograph linkage provided with a tracing sty-i lus a support for said spindle mounted on one member of said pantograph linkage, a pattern;

, support; located in position to be' traversed by .said tracing stylus, a rotary feed handle and,

gearing connecting said feed handle to said die holder to rotatethe latter about the axis of jthe die to produce the cutting feed during grinding.

4.11m a machine for grinding the lands of but-5 J ton s'crewdies, the combination of; a die holder .mounted for rotation about th axis offa die;

carried in said die holdenga spindle journalled to rotate about an axis parallel to that of said;

i dieholder, a support for said spindle, power means for rotating said-spindle, means tor-mov ing-saidgsupport to effect movement of said spindle along v a --predetermined path conforming to the profile to be ground, a rotary reed handle, gearing connecting said feed handleto said die holder to rotate the latter about the axisof the die .to producethe cutting feed during grinding, and-anadjustable stop'locatedtoco act with said I Jess handle to limit the maximum amount of the engine feed.

holder, power means for rotating said spindle, a pantograph linkage provided with a tracing stylus, a support for said spindle mounted on one member of said pantograph linkage, a pattern sup-w l located in position to betraversed by said} tracing stylus,"a'rotary feed handle, gearing con--:

meeting said feed handle to said die'holder to rotate the latter about the axi's' of the die to? produce the cutting feed during grinding and an. adjustable stop locatedto co-act w'ith' said," feed. handle to limit the maximum amount ofi.

? the cutting 'feed.

"a m a.m'achine for grind ing the land or but-i ton screw dies, the combination of a die holder mountedior rotation about the axis of adie carried in said the holder,: a spindle journalleditq' rotate about an ax s parallel to that ofsaiddie holder, .a support for said spindle, power means for rotating said spindle, means 'for moving said support to effect movement ofsaid spindle along a a predetermined path conforming to theprofilej v tobe ground, a rotary feed handle, gearing connecting said feed handle to said die holder to rotatathe latterabout the axis of the die to 1 i r a machine for; grinding the'lands of butL ton screw dies, thecombination of a die holder mounted fOr rotation about the axis of a die cartied in said die holder, a spindle journalled to, rotate about an axis parallel to that ofa-saidgdie produce-theyfiuttingiced z q v 'i a one-way clutch interposed-between said teed handle and'said die holder; to perm-it s mdie,

holder to'turnforwardly while said feed handle-is stationary; I I 7 a n performing a pluralityf grinding operations-atgspaced angular positions On a metal workpiece, the' combination of-a -stationary machine frame, a work-holder mounted for rotation-in said frame,- a grinding wheel spindle journalled to rotate about an axis parallel f to that of said work-holder; a support for said spindle, powerjmeansfor-rotating "said spindle, a:

work-holder registering device comprising; a ,re-

siliently actuated pivoted toothlocated toi engage I a notch in each of a plurality of angular positions of said work-holder, means for moving said support to eifect a predetermined relative movement between saidspindle and said work-holder in each of the angular positions ofsaid workholder and manual means for rotating said work;- holder to produce the cutting feed during each of a plurality of grindingoperationa I "8. In a machine forgrinding the landsof buts ton screw dies, the combination ofastationarymachine frame -adie holder mounted --for rota- I tion in said frame and furnishedhwit-h a;plural ity of angularly spaced peripheral notchenya grinding wheel spindle journa'lled torotateabout 1 anaxis parallel to that of said die holder, Ia

- supp orspindlegpo rv mea s for-rotat .ing; said spindle, a resiliently; actuated pivoted tooth located toenga'ge ineach ofsaid notches I to registersaiddieholder in a plurality organton screw dies, the combination of a stationary machine frame; a die holder mountedjfor rota-= ti n-in-said frame and iorm'edwith a peripheral rim furnished with a-plurality of angularly spaced gular positions,'- means for moving said support to cause a predetermined-relative movement-betweensaid spindleand said die holder'iin each o nih ansarms s o e lat riian im nual meansor sa d'adie hol r t predu e h cutting feed during 'eachof a plurality of grind ingoperationa '9.- In gamachine for grinding the lands of butnotches, a grinding Wheel-spindle journal-led to rotate about an axis paraIleltothat of said die holder, a support for said spindle, power means for rotating said spindle. a rotary feed handle. earingwconnectingsaid feed handle to said-die holder to rotate the latter about the axis of the dieqto produce the cuttingfeed-during grindin a resiliently-actuated tooth pivoted to said machine frame inposition to engage each: of said notches to register said-die holder in a plurality of angular positions and means for movin said support :to cause a-predeterminedrelative movement between saidspindle-and sa d die holder in eachof the angular positions of thelatterv @110; In-amachinefor grindingthe lands of but- '.ton screw dies. the'comhination of a stationary machine frame, a die holder mountedfor rotation in said trame and formed with aper iphera'l rim furnished witha, plurality of angularlv spaced notches, a grinding wheel spindle journalled to rotate aboutjan axisparallel to that of said die holder. a support for said spindle, power means "for rotating said spindle, a rotary fe'ed handle,

gearing conneoting said feedhandletoisaid holder to rotate the latter about'the axis of the die toproduce the cutting-feed during grinding,

a resiliently-actuated tooth pivoted to said ma chineframe'inposition to engage each of said notchesto register said-die holderin a. plurality of. angular positions, means for moving said support to cause a predetermined relative movement between said spindle and said die-holder in each of the angular positions of the latter, and madjustable stop located to co-act with said feed handie to limit the maximum amount ofthe cutting feed.

11. In a machine for grinding the lands'of button screw dies, the combination of a stationary machine frame, a, die holder mounted for rota rim furnished with a plurality of angularly spaced notches, a grinding wheel spindle journalled to rotate about an axis parallel to that of said die holder, a support for saidspindle, power means for rotatingsaid spindle ,-a rotary feed handle, gearing connecting s'aidfeed handle to said die holder to rotate the latter about the axis of the die to producethe cutting feed during grinding, a resiliently-actuated tooth'pivotedto said'inachine frame in position to engage each of said'notches to register said die holder in a feed during grinding, a one-way clutch inter- P tion in said frame and formed with aperiph'eral plurality of angular positions and means for 12. In a machine for grinding the lands of but- 7 ton screw dies,.the combination of a stationary machine frame, a die holder mounted for rotation in said frame and formed with a peripheral rim furnished with a plurality of angularly spaced peripheral slots, a grinding wheel spindle journalled to rotate about an axis parallel to that of said die holder, a support for said spindle, power means for rotating said-spindle, a resilientlyactuated tooth pivoted in said machine frame in position to engage each of said notches to register said die holder in a plurality of spaced angular positions, meansfor moving said support to cause a'predetermined relative movement between said spindle and said die holder in each of the angular positions of said die holder, a rotary feed handle, gearing connecting said feed handle to said die holder to rotate the latter about the axis of the die to produce the cutting feed during grinding and a one-way clutch interposed between said feed handle and said die holder to permit saiddie holder to turn forwardly while said feed handle is stationary, each of said notches being shaped on one face to cause disengagement of saidresiliently-actuated tooth during the rotation of said die holder by said feed handle in effecting each of a plurality of grinding operations. i

13. In a machine for grinding the lands of but: ton screw dies, the combination of a stationary machine frame, a die holder mounted for rotation in said frame and formed with a peripheral rim furnished with a plurality ofangularly spaced peripheral slots, a grinding wheel spindlejournalled to rotate about, an axi parallel to that of said die holder, a support for said spindle, power means for rotating said spindle, a resilientlyposition to engage each of said notches to regof the angular positions of said die holdere rotary feedhandle, gearing connecting said feed handle to said die holder torotate the latter about the axis,of the die-to produce the cutting posed between said feed handle and said'die holder to permit said die holder to turn forwardly while said feed handle is stationary;'and an adjustable stop located to co-act with said feed handle to limit the maximum amount of the cutting feed during each of a plurality of grinding operations, each. of said notches being shaped on one face to cause disengagement of said resiliently-actuatedteeth during the rotation of said die holder by said feed handle ineffecting each of said grinding operations. l

14. "In a machine for performing a plurality of grinding operation at, spaced angular positions on a metal work-piece, the combination of a stationary frame, a work holder mounted for rotation on'said frame and furnished with a plurality of 'angularly spaced peripheral notches, a

. grinding wheel spindle journalled to rotate about an axis parallel to that of said work holder,

powerfmeansfor rotating said spindle, a p'antograph linkage provided with a tracingstylusja support for said spindle mounted on one member of said pantograph' linkage, a pattern support located in position to be traversed by saidtracing stylus, a resiliently-actuated tooth pivoted in said machine frame in position to engage each of said notches to register said work holder in a plurality of spaced angular positions, a rotary feed handle, and gearing connecting said feed handle to said work holder to rotate the latter about the axis of the die to produce the cutting feed durmg each of the plurality of grinding operations.

15. In a metal grinding machine, the combination of a stationary machine frame, a work 'holder mounted for rotation and guided for axial reciprocation in said machine frame, a grinding wheel spindle journalled to rotate about an axis parallel to that of said work holder, a support for said spindle, power means for rotating said spindle, a camshaft journalled in said machine frame, cams on said cam shaft co-acting with said work holder to effect reciprocation of same,

in said machine frame, means for moving said support to cause movement of said spindle along a predetermined path, and manual means for rotating said work holder to produce the cutting feed during grinding.

"ment of said spindle along a predetermined path,

actuated tooth pivoted in said machine frame in Y about the axis of the die to produce the cutting 16. In a machine for grinding the lands of but ton screw dies, the combination of a stationary machine frame, a die holder mounted for rotation and guided for vertical reciprocation, in said frame about the axis of a die carried in saiddie holder, a'grinding wheel spindle journalled-to rotate about an axis parallel to that of said die holder, a support for said spindle, power means for rotatingsaid spindle, a horizontal cam shaft journalled in said machine frame, cams carried H by said cam shaft and co-acting withsaid die holder to effect vertical reciprocationof same, meansfor moving said support to cause moveconforming to the profile to be ground, a rotary feed handle and gearing connecting said feedhandle to said die holder to rotate the latter feed during grinding.

ister said die holder in a plurality of spaced ani 17. In a metal grinding machine, the combination of a work holder mounted for rotation, a

grinding wheel spindle journalled to rotate about tween said .spindle and said die "holder'in. each'y an axis parallel to that of said workiholder pa support for said spindle,,compressed air motor having its rotor secured tosaid spindle, a conduit for supplying compressed air to said air motor, a manually-operated valve for controlling airjflow throughsaid con'duit,'means for moving said support to cause movement of saidspindle along a predetermined path, and manual means for rotating said work holder to produce the cutting feed during grinding, I g

l8. In a machine for grinding the lands of but ton screw dies, the'combination, of a die holder mounted for rotation aboutthe axis of a die carriedin said die holder, a grindin Wheel spindle journalledto rotate'about an axis parallel to that I of said die holder, a compressed air motor having its rotor securedtosaid spindle, a conduit for supplying compressed air to said'air motor, a

manually-operated valve for controlling air flow through said conduit, a support for said spindle,

' means for moving said support to cause movement of said spindle along'apredetermined path er mounted forrotation and mounted in said machine frame .toslide transversely to its axis'of rotation; means for locking said work holder in said machinegframe after sliding into a predetermined position, a grinding wheel spindlejournalled torotate about an axis parallel to that of said work holder, a support for said spindle, pow er .means for rotating said spindle, means formoving said support to cause'movementof: said spindle :alonga-predetermined path, and manual I means for rotating said work holder to produce the cutting. feed during: rinding.

20. In a machine for'grinding the, lands of but ton screw dies, the combination of a stationary. machine frame, a horizontal slide carriedin said frame, a die holder'supportedon said slide and mounted for rotation about the axisof a die car- 'ried in said die holder, a lockingscrew for lockconforming to the profile to be ground, a'rotary feed handle, and gearing connecting said feed handle to said die holder to rotate the latter:

ing said slide in a predetermined adjusted position in said frame, a grinding wheel spindle journalled to rotate 'about'an-axisparallel to that of said die holder, a support-for said spindle, power means for rotating said spindle, means for moving said support to cause movement of said spin dle along a predetermined path conforming to the profileto be ground, and manual means for rotating said die holder about'the axis of the die to produce the cutting feed during grinding.

' EDGAR. BANNISTER.

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