US2857716A

US2857716A - Grinding apparatus

Info

Publication number: US2857716A
Application number: US689701A
Authority: US
Inventors: Frank J Woidka
Original assignee: Saginaw Machine and Tool Co
Current assignee: Saginaw Machine and Tool Co
Priority date: 1957-10-11
Filing date: 1957-10-11
Publication date: 1958-10-28
Anticipated expiration: 1975-10-28

Description

Oct. 28, 1958 F. J. WOlDKA GRINDING APPARATUS '7 Sheets-Sheet 1 Filed 001;. 11. 1957 INVENTOR. FRANK J. WOIDKA lllllllFlI-l ATTOBNEYS Oct. 28, 1958 J, wo 2,857,716

GRINDING APPARATUS Filed Ocb. 11, 1957 7 SheetsSheet 2 INVENTOR. FRANK J. WOIDKA ATTORNEYS Oct. 28, 1958 F. J. WOIDKA GRINDING APPARATUS '7 Sheets-Sheet 3 Filed Oct. 11. 1957 A MK TD m0 VW m. d K N A R F AT TOR NEYS Oct. 28, 1958 F. J. WOIDKA GRINDING APPARATUS '7 SheetsSheet 4 Filed Oct. 11, 1957 IN V EN TOR. WOIDKA m @J/M IU- K N A R F a W Y 3 6 l 5 mm m 3 l m\ 7 4 #2 a M 6/3 I 8 l M g 3 I M 9 mm M 0 mm 4 t a m 2 rr. 3 l m ATTORNEYS Oct. 28, 1958 wo 2,857,716

GRINDING APPARATUS Filed Oct. 11. 195') 7 Sheets-Sheet 5 INVENTOR. FRANK J. WOIDKA ATTORNEYS Oct. 28, 1958 F. J. WOlDKA 2,857,716

GRINDING APPARATUS Filed Oct. 11, 1957 7 Sheets-Sheet 6 FIG. 9

FIG. IO

FIG. 8.

INVENTOR. FRANK J. WOIDKA ATTORNEYS Oct. 28, 1958 F, J, wolDKA 2,857,716

GRINDING APPARATUS Filed Oct. 11, 1957 7 Sheets-Sheet 7 FRANK J WOIDKA ATTORNEYS United St t Patfim GRINDINGAPPARATUS 'Frank J.Woidlra, Saginaw,"Mich.,,,assignor ,to Saginaw Machine and Tool Company, Saginaw, Mich, a corporation of'Michigan Application October-11, 1957,;Serial No. 689,701

19 Claims. (Cl. 51 "127) This inventionrelatesz-to grinding apparatusand: more particularly to grinding apparatus especially cladapted automatically to grind single point carbide tools: to ,any one of a .number of predetermined :profiles.

The grinding of tools with whichtthe inventiontis concerned.heretoforetrhas been largely a :matter: of .skill vonthet-parrof the machine operator. 1That:is,-.a tool grinder charged with the-responsibility .of :producing: a tool'having a particular .profilei would 1 be required-.10 devote substantially constant attentiQn'tQxJthe grinding operation. in order to:position itheworkpiece: relatively to the grinding wheel in such 'rmanneras toJshapea/the 'end .of thewworkpiece according .to .the1'predetermined :profile. Due to .human .frailtiesit isaalmost impossible to produce a number of toolsin thisrmannerhavingidentical profilesand, t with the advent of? automationeequipview being along the line2-2 ofFigure 1;

Ihefollowing "description whenit, is considered in con- .cordancewiththe invention, the :view beingtaken generally along the lined-. 1 .ofFigure .2;

Figure-2 .is a par'tlysectional and partly side elevationalview of themachine and disclosing the relation of .thejtool holderto-a grinding Wheel, the sectional Figure 3 is, avview p'artly-.=in front-elevatiomand partly -.in section, the section being taken; alongthe 1 ine. 33..of

. Figure 2;

.showing .theiapparatus for effecting movements of the .tool holder;

Figures 7-l0 are: planviews of typicaltoolsand the templates wused'sin .thelgrinding thereof;

.ment requiring-the use of alarge'numbenofidentical tools, small differences in supposedly identical .tools can -lead to large numbers of unacceptable productswhich -must either be reworked or scrapped.

Apparatus-constructed inaccordancewith the-invention includes tool holder means which is mounted for movement relative to agrinding-wheel, the -movement of thetool holder being controlled by atemplateaxhaving I predetermined cam c contours thereon: ilective to: move the tool holder automatically to and'tronr-a .number "of positions so as to producethe desired profile on the tool held by the tool holder. The-apparatus also includes means for automatically feeding the: tool to the :grinding whe'el 'so'as to enable'the grinding-. operation to 'becompletely -autom'atic-once it-has "been initiate'd. Because of the mechanical positioning and gfeedingofthe workpiece, successive tools each having a'profile formed :according :to a s'elected template -will be identical. To.

provide the apparatus -with ai=lar ge degree; bf fiexibili'ty provision is -made for the substitution of templates-havfi ing different cam' contours so: as to enableutools having -idifferent profiles to i be -produced by thesame machine xm'erely'i by. :the substitution of templates.

J'An object of the inventioni isuto a-pro'vide; :toolegrinding a 'apparatus'.capable of!grindingxsuceessivez tools to iden- -Anothertobject of the invention: is .tozprovideutool grinding: apparatus. ofvthezkind referred? .torzhavingztool- :holdingameans movable relatively'to. azzgrindingsivheel ':under the influence of arttemplateuhaving cam surfaces a substantially horizontal plane. corners of the carriage 10 is an upstanding-member 11 .Figure 11. =is.a fragmentary, partly sectional and partly plan. view. of a modified part of. the apparatus; and

Figure 12 is;.a;.section'al view takenaalong. the line 12--12 of Figure 11.

, Ap'paratus formed .in. accordance :With the illustrative .embodiment of the. invention: disclosed ina Figures 1-6 .-of the drawings may comprise a vbase'l composed of a .bed 22 adapted for connection to a suitable pedestal or arms 7 at each of its four corners and inea'ch of which is mounted-asubstantially horizontally extending shaft :8 on which isjourneilleda roller-9. 'A carriage member 10 is mounted on the trollers-9 for reciprocating movements along apa'th fore and aft. of the-machinebed in At eachof-the-four which is beveled as at 12 and which is providedwith' a thereon formedin suchumanner EaS-IItO .eifect em'ovements 'aof thektool holder to'grind a..predetermined profileuon the carriage.

=bearing b1ock13 which bears against a roller 14 jour- 'nalled' on a'shaft 15 mounted in the adjacent support 7, -the arrangement being such that-the rollers 14 overlie the carriage 10 and guide the latter in its movements.

-Between the front and rear sets Ofmembers 11,-;the

Fig. 2) on which is mounted a pair. of spaced apart rails 17 extending parallel to one another and in a direc- 'tion substantially normal to the path of movement of Each of the rails 17 is grooved as-at 18 forthe reception of two pairs of rollers" 19, each or the rollers'being journalled on a shaft 21 mounted in a slide 21. The construction and arrangement of the parts thus far described are such that the carriage 10 is capable of reciprocating movement fore and aft of'the machine, whereas the slide 21 is capable of movement withthe carriage-and 'also is capable of reciprocating movement from side to side relative to the carriage. v

"Referring again principally to Fig. 2, the carriage 1i isprovided adjacent to its rear edge and substantially intermediate the rear supporting members 11 with a- -tubular casing 22 equipped at its lower end 23 withfa hall-race assembly 24 and atits upper end 25 with a similar ball-race assembly26 by means of which a spindle 27 is rotatably mounted. The upper end 28 of the spindle extends'through an opening 29 in the housing 3. and pro niects beyond the latter, "the opening29 being considerably; larger than thediameter o-f;;the-1spindle. 271fora pointed out specifically or will become apparent from I purpose presently to be explained. The opening 29 is surrounded by an upstanding boss 30 in the upper surface of which is mounted a dust-sealing ring 31.

Tool holding means designated generally by the reference character 32 includes a mounting or crank arm 33 which receives the projecting end 28 of the spindle 27 and is fixed relatively to the latter by suitable means such as a set screw 34. The arm 33 includes a depending skirt 35 which overlies the boss 30 to assist in preventing the entry of grinding dust to the interior of the housing 3. The tool holder mounting arm 33 extends radially from the spindle .27 and is provided adjacent to its outer end with a tool indexing device 36 on which is mounted a tool holder 37 adapted to present one end of a tool T to a rotatable grinding wheel W which may be mounted at the end of a rotatable shaft 38 driven by suitable motor (not shown). The grinding wheel and its driving shaft 38 preferably are so mounted that the plane of the grinding wheel is at an angle to the vertical as is shown in Fig. 2 so as to enable the tool to be pro vided with the proper degree of rake. The grinding wheel W may be supported by a machine separate from the apparatus forming the invention, or, alternatively, the grinding wheel and its driving shaft 38 may be mounted on a pair of supports 39 fixed to the housing 3 (see Fig. 3), in which event suitable means will be provided for locating the grinding wheel in substantially the position shown in Fig. 2 and, if desired, oscillating the grinding wheel from side to side to promote even wear of the grinding surface. This mechanism forms no part of the invention per se and, hence, is not shown in more detail.

Referring particularly to Figs. 1 and 2, the slide member 21 is provided with a central web portion 40, the upper surface of which is substantially horizontal and is equipped with tapped openings for the reception of threaded screws 41 by means of which. a plate-like template or cam plate 42 may be removably secured to the slide 21. The particular template 42 shown in Fig. 1 has cam surfaces 43, 44, 45, 46, and 47 on its rear edge and cam surfaces 48, 49, 50, 51, 52, and 53 on its front edge, the two cam edges being at opposite sides of the body portion 54 of the template 42. The particular configuration of the template 42 is so designed as to produce a tool T having the profile shown in Fig. and about which more will be said subsequently.

The cam carrying slide 21 is accessible for the purpose of changing templates by the provision of an opening 55 in the housing 3, the opening 55 being closed during operation of the apparatus by a removable cover plate 56 which prevents the entry of grinding dust to the interior of the housing.

As is best shown in Figs. 1 and 2, the front wall of the housing 3 is provided with a tubular element 57 in which is slidably mounted a rcciprocable part 58 carrying at its inner end a cam follower or roller 59 journalled on a pin 60, the part 58 being movable under the influence of a hand wheel 61 to and from positions in which the cam roller 59 bears against the rear edge of the template 42. The cam follower 59 may be set to the desired position and checked by means of a pointer 62 adapted to be read in conjunction with an indici carrying element 63 which rotates with the hand wheel.

At a point in line with the line of action with the cam follower 59, but arranged to bear against the opposite side of the template 42 is another cam follower or roller 64. The follower 64 is journalled on a shaft 65 mounted at the inner end of a reciprocable plunger 66 W1. ichis mounted for sliding movements fore and aft of the machine adjacent to the upper end of the tubular spindle housing 22. The plunger 66, during operation of the machine, is constantly urged in a direction to cause the cam follower 64 to bear against the rear edge of the template 4-2 by a piston 67 of a hydraulic or pneumatic cylinder 68 of known construction and which will be described in greater detail hereinafter. A second cylinder 69 of similar construction is mounted on the housing 3, its piston rod 70 extending through an opening 71 in the housing and located so as to bear against the rear edge of the carriage 10 fora purpose presently to be explained.

Means is provided for interconnecting the plunger 66 and the spindle 27 to impart rotation to the latter and, consequently, to the tool holding means 32 upon movement of the plunger 66 relative to the carriage 10. In the illustrative embodiment of the invention the connection between the plunger 66 and the spindle 27 is effected by flexible steel tapes 72, 73, and 74, the strip 72 having one of its ends anchored to the plunger 66 by a pin 75 and its upper end passed around a portion of the spindle and anchored to the latter by a pin 76. Corresponding ends of the steel tapes 73 and '74 are passed around a portion of the spindle 27, but in an opposite direction to the direction in which the tape 72 is Wrapped, the ends of the tapes 73 and 74 being fixed to the spindle by pins 77. The other ends of the steel tapes 73 and 74 are anchored to corresponding ends of pins 78 which extend through ears 79 mounted on the plunger 66. The other ends of the pins 78 are headed as at 80 and reacting between the heads 80 and the cars 79 are springs 81 which tension the tapes 73 and 74. The connection of the plunger 66 to the spindle 27 is such that reciprocating movement of the plunger will impart rotary motion'to the spindle 28 and the rotary motion will be effected wtihout backlash.

Still referring principally to Figures 1 and 2, a pressure fluid responsive device 82 of known construction is mounted by means of brackets 83 (Fig. 2) on the dropped bottom portion 16 of the carriage. The device 82 comprises a cylinder 84 having a 'reciprocable piston 85 mounted therein, the latter being connected by a piston rod 86 to an end wall 87 of the slide 21. The pressure fluid responsive device 82 is connected in a manner presently to be described to a source (not shown) of pressure fluid so as to effect reciprocating movement of the slide 21 and the template 42 along a path at right angles to the path of movement of the carriage 6. At the end of a stroke to the left, as viewed in Fig. l, a switch operator 88 strikes a contact arm 89 of a limit switch 90 which reverses the movement of the slide 21 in a manner presently to be described so as to drive the slide and the template 42 to the right as viewed in Fig. 1. At the end of the stroke to the right, the end of the piston rod 86 strikes a contact arm 91 of a second limit switch 92 which causes the cam slide 21 again to move towards the left.

Apparatus for actuating the

cylinder parts

67 and 70 and effecting reciprocating movement of the cam slide 21 is diagrammatically illustrated in Fig. 6 and includes a hose or tube 93 connected at one end to a source (not shown) of pressure fluid and at its other end to a solenoid operated valve 94 of known construction. The solenoid armature 95 is provided with a winding 96 having one of its ends connected by a Wire 97 to a source of suitable electric power such as 110 volt 60 cycle alternating current. The other end of the winding 96 is connected to the power source through a main switch 99.

From the valve 94 lead two

conduits

100 and 101, the conduit 100 communicating with the cylinder 68 at that end of the latter which is mounted nearer the housing 3, whereas the conduit 101 is similarly connected to the cylinder 69. A branch conduit 102 interconnects the opposite end of the cylinder 68 to the conduit 101 and a similar branch conduit 103 interconnects the opposite end of the cylinder 69 to the conduit 100. The arrangement of the parts thus far described is such that when the parts of the valve 94 are located to deliver pressure fluid through the conduit 101, the piston rod 67 and the plunger 66 are urged in a direction towards the template '42, and the piston rod 70 is urged in the opposite direction; When' theparts;ofthe"vhlve"4 are in 'theirother "positions," as determined the position of; theswitch '99 'pressureifiuid'is' supplied to""theline 100" so'as to eflect movement of the: piston" rods67; and 70" in'directions'opp osite tdthose 'j ust referred to. Theisignificance ":of the cylinder 69 and its associated piston'rod 570 i will be "pointed out in the discussion of: the operation of ythe apparatus. i

"alternating current and; its other end; connected by a wire 'i113'to1'the contact tarmffl of the'swlit'ch92: The other contact, of the swjitch'"92;.is' connected b'y a wire 114 to f'thejpower source. IThe'arniature'1I5 bf'the othersole- M 'rnoid'. in the valve '107 has a winding,116' therearound, one end of which is connected by a wirll'l to lthe'wire 112. arid the othenend of. whichis connected by. ,a Wire '118 toa contact of itheflimit;switch '90. The contact arm'}89' of theswitehfiti is connected byta wire 119 to the .iwirelll4.

'The -operation. of.- the valYei I 07 isisuchf'that, whenfthe .switchoperator parti88 onithe slide21 closes the switch 90 pressure fluid, su'chaas; air, from. the'line 104. passes .iith'rou'gh rhevalyei107, and into the 'cyjlirider 84 to move "the. pistonLS S, the .piston rod} 8,6,. and the template 42L-to .the right aszviewed". in .FigQQG. a'As,vltherpiston tmoveslto the right, air is :exhaustedafrom the :opposite endtofithe "cylinder-84, throughatheI liner108, rand ;then t'hrough the waive 1107 l touatmospheref twhen the end of the piston rod 86\str.ikesi;the. switch 92, airisadmittedithrough the valve i, 107 v to .the cylinder 84 through ,the .,J1ine 1081 --eifect movement, of the; pistonl85,-. in Qithe, opposite direcc-tion. -.During;the latter movement of the piston; airl from .rsfollow'ers64 bears against theiopposite cam surface of the template. 'If Jthe'position of the 'slidefr2lis such that the cam follower 59 bears againstthe cam surface'49 just to the left of. the bevelled su'rfac'el'48, and the cam'follower 64' bears: againstthe' cam surface "43, "the poSitiOnof; the tool holder will be' such-that the tool'Tlis'so located'as to have'theprofile 'surfa'ce'43a ground on the e'nd there- 1 of. As the" template 42-pr0gresSestowafd theright, as

' viewedin Fig. l, the-tobl will;c0ntinue to be-held inthis position until such 'time as' the cam follower -64 engages tlie'carrfsurface 44. At this point the 's lide- 66 will be forced rearwardly of .itheimachinezand theire'arward movement of the slide 66 will simpartcounterclockwise:rota- -tion=to .:the spindle. -27,::as-z viewed imFig. 1, and conseiquently, counterclockwise; rotation to the tool fT, about a point which" lies substantially 011 1116 axis ofrotation of e the spindle: 27. --As :the, plunger." 66; :is -pushedrearwardly -by thezcam surface 44, the stool 'holder willabe. swung relatively to thelgrindingrwheel: so: as; to j grind a: radius 44a on the end of thetool. Thetlength'ioftheradius e445: will/be; zdeterminedt byl:therlength: of; the: surface 44. wWhen thes movementxofcthe E slide :21 anduthe template of*t,-he'-s1ide-21 to the" right willfg'rind" a flat I surfacef iSa *Qn-theendof the-to'oPT. 'When'the movement ofthe slidezl' and the templatef tz 'has progressed to the point "where the cam follower '64 is about to traversethei,cam

surface 46, the cam follower '59'will'bein'a position to 1 traverse. the 'cam "surface 0. At' thispbint, thei force eicertedton the template"42-'hy'the'pressure" cylinderf68 "will effect for'wardmovenientfbf'the' carriage 10* relative 10" to the base 1"until snchtirneasthecamfolloWerJSSl is movement of'the carriage 1 0will feffect movement of the to'ol holder away"from;'the i grinding wheel' W so; as to prevent grinding of the" .tool during this phase of operation' ffthe apparatus. During-the time" thatthe' tool is 1 out of engagement with thegrindingjwheel. W,j'the-'1fnovement of" the slide 21 underthe influenceiof the pressure device 82 'will' continue so as to causef the" cami follower .164' tof traverse the cam surface 46. Thus; the v.plunger 66 will be'force'd'rearwafdly relatively to the carrizjig'- 10 .so,. as to eifect counterclockwise rotation of'the spindle T27 and, consequently; counterclockwise rotation of the to'ol'holder. Durin'g thegrotation or swinging of the 'tool holder,i"the 'cami follower'f59 lwill he -traversing the cam in engagementwith "'thefcam surfacefsl. The"forward Lto returnTthetooltiiito engagement withthegrinding wheel. When themove'me'nt iof'the ,slide."'2llhas,. pro- 'mg'ressed' to the point where; the camfollower 59' traverses 'jthe cam surface "53 arid "the earn"-fol1o wer64 traverses about which, the tool 1s.swung. is moved tlaterally, but

.in a blocle128. To rigidity the connection of "the parts,

position of the parts shown in Fig. 1, further movement relation. of the surfaces '45a .andjf47a will. be angular.

That is,vbetween the surfaces 45a. arid '47alwi1l be. an angle 46a as opposed totaradius.

, As. is. best shown in'Figrll, the, cam. surfaces 49 and 'T53. do -not lie in the same verticalplane, hut, rather,.- the carn-'surface 53 is offset forwardly withn-re'spect vto lthe cam surface 49. The eifectofthe oifset is that. the .point remains eon theaaxis of the spindle 27.

When the slide 21 has completed its movement ,to .the right, as viewed inEig. 1, the end of the piston-.rod--86 will trip theswitch 92 to cause movement oflthecam slide 21 towards the left. As thets'lide -moves-to..the left, -the cam'followers 59 and 64 will re-traverse the several cam surfaces and will cause the tool to be swung in a ..direction opposite to that previously desc'ribedso as. to :present theseveraln-profile surfaces ofrthe tooltothe grinding wheelfor further grinding. Atthe endtof its left handstroke, the switch .operat'or, 88 will (actuate the switch 90 to c'ausenmovement of the 's lideIZI againvto the right. 7

Referring now more particularly to Figs. .4 and5,lthe ,ttool ho-ldingmeans 32idisclosed therein for purposes of illustration comprises a-shaft journalledtfor rota- .tion at the radiallyouter end of the tool-holder supporting arm 33. In assembled relation, the shaft125 extendsvertically and -carriesaat its .upper end an eccentric part126 which. is received inan opening 127 formed the: arm 33 is provided with an upstanding tubularlb'oss 129 which, in turn, is provided with a reduced diameter .ext-ension 130 which is received withinan opening'131 in communication with the opening 127. A thrust bearing 132 surroundsthe shaft 125 and is seated on 1 the base of the opening 127 to assure'r'etention of the shaft in its proper location.

' Theopening 127 is provided with "a 'recess'1 33, in which is located a roller '134 rotatably mounted on a shaft 13'5 which1 is secured to the'bloclc128 by means of a threaded nut 136. Theblock 128 is-providedon mwh'ichxis slidablyrrec'eived a correspondingly;slottedxtool holding element 138, the latter including upstanding sidewalls 139 between which the tool T may be placed and secured by wedges or shims 140. The position of the tool holding element 138 may be held in adjusted relation relative to the block 128 by means of dowels 141 and setscrews 142 (see Fig. 4).

At the lower end of the shaft 125 is fixed, by means of a pin 143, and adjusting wheel 144 which is operable to impart rotation to the shaft 125. Rotation of the .shaft 125 will cause the eccentric part 126 to bear against the roller 134 to effect movement of the parts 128, 139 and T towards and away from the grinding wheel a distance corresponding to the difference in diameters of the extension 130 and the opening 131. The aforementioned parts of the head 37 are moved away from the grinding wheel upon rotation of the shaft 125 in a direction to disengage the eccentric part 126 from the roller 134 by the operation of reeds 145 formed of spring steel or the like and secured to the arm 33 and the block 128 by

shim blocks

146 and 147, respectively.

It is preferred that the rotation of the shaft 125 in a direction to feed the tool T towards the grinding wheel be effected automatically during operation of the machine and this may be accomplished by the provision of the indexing device 36. The indexing device 36 comprises a toothed ratchet wheel 148 fixed on the shaft 125 by means of a pin 149, the device 36 also including an arm 150 loosely mounted on the shaft 125 and having pivoted at its outer end, as at 151, a pawl 152 which is urged by a spring 153 into engagement with the teeth of the ratchet wheel 148. The arm 150 normally is maintained in the position shown in full lines in Fig. by means of a spring 155 having one of its ends enchored to a hook 155a fixed on the arm 150 and its other end anchored to a post 1551: mounted on the crank arm 33. When, however, the tool holder 37 has been rotated to a position it must occupy to grind thetool profile surface 47a, the arm 150 will engage an adjustable stop member 156 which is mounted on a bracket 157 secured to the upper wall of the housing 3 by suitable means such as a bolt 158, and the engagement of the arm 150 with the stop 156 will efifect clockwise rotation of the ratchet wheel 148, as viewed in Fig. 5, and, consequently, corresponding rotation of the shaft 125 so as to cause the eccentric 126 to bear against the roller 134 and move the assembly 37 towards the grinding wheel. When the tool holder is rotated away from the adjusting part 156, the spring 155 will return the arm 150 to its normal or inactive position, but the ratchet Wheel 148 will remain in adjusted position under the influence of a locking pin 159 which is yieldably urged into engagement with the teeth of the ratchet wheel by a spring 160 which reacts against the pin 159 and a threaded stop 161 mounted in the arm 33.

After the tool T has been ground, it may be removed from the holder and another workpiece positioned therein. The second workpiece will be ground to the identical profile of the tool T, as will successive workpieces, as long as the template 42 is used to control the movements of the tool holder. Accordingly, large numbers of identical workpieces may be formed without relying heavily on the skill of the operator of the machine.

Apparatus constructed in accordance with the invention is capable of producing a wide variety of tools. Illustrative examples of tools capable of production on the apparatus are shown in Figs. 7-10. In each instance, the profile of the tools T T T T is produced by the

templates

42a, 42b, 42c, 42d, respectively,

each of which is shown immediately to the right of i template. The examples shown in Figs. 7-l0 are intended to illustrate the flexibility of apparatus constructed in accordance with the invention and are not to be construed as limiting the use of the apparatus to the production of the particular tools shown.

When it is desired to change templates, the slide 21 should be moved far enough to the left, as viewed in Fig. 1, to enable the cam follower 59 to engage the bevelled cam surface 48 of the template. The slide may be maintained in this position opening the switch 99a in the line 112. Thereafter, the switch 99 may be opened to effect movement of the parts of the valve 94 to such positions that pressure fluid is exhausted from the cylinder 68 through the line 102 and is admitted to the cylinder 69 through the line 103 so as to project the piston rod 70 forwardly and retract the piston rod 67 and the plunger 66. The retraction of the piston rod 67 will disengage the cam follower 64 from the template 42 and the projection of the piston rod 70 will cause the latter to push against the carriage 10. Thereafter, the handwheel 61 may be revolved to retract the cam follower 59. As the cam follower 59 is retracted, the carriage 10 will be moved forwardly until it strikes a stop (not shown), thereby positioning the template 42 in a position easily accessible through the opening 55 in the housing 3. At this point the template securing parts 41 may be withdrawn and another template substituted for the template 42. During the substitution, the piston rod 70 will hold the carriage in locked position. After the substitution of templates has been made, the apparatus may be conditioned for operation in the manner previously described and used to form a tool of predetermined profile.

In Figures 11 and 12 there is disclosed alternative apparatus for effecting rotation of the spindle and, consequently, the tool holder. In the modified construction, the tubular casing 22 is provided with a pair of

guideways

163, 164 in which is mounted a corresponding pair of

toothed rack elements

165, 166. The rack elements are mounted for reciprocating movement in the guideways and are supported in the latter by anti-friction balls 167. One end of the rack element 165 is bifurcated for reception of the cam follower roller 64 which bears against the template 42 in the same manner as previously discussed, whereas the opposed end of the rack section 166 is abutted by the end of the piston rod 67. The spindle 27a is provided with a plurality of longitudinally extending teeth 168 which are so arranged as to mesh with the teeth 169 of the

rack elements

165 and 166. The arrangement of the several parts is such that fluid pressure acting on the piston rod 67 causes movement of the rack section 166 to the right, as viewed in Figure 11, so as to impart counterclockwise rotation to the spindle 27a. Rotation of the shaft 27a in counterclockwise direction will effect movement of the rack element 165 towards the right, as viewed in Figure 11, so as to cause the cam follower 64 to bear against the template 42 and locate the tool holder in such position as to grind the desired profile surface on the latter. When the contour of the template 42 is such as to effect movement of the rack 165 to the left, as viewed in Figure 11, the rotation of the spindle 27a will be reversed.

The construction and arrangement of the toothed spindle 2712, the

co-operating rack elements

165, 166, and the template 42 are such that force is applied to one of the rack elements in one direction and force is applied to the other rack element in the opposite direction. As a result, rotation of the spindle 27a may be effected in either direction without backlash.

The disclosed embodiments are representative of presen'tly preferred forms of the invention but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.

egenerate .-=.relative..to-;said base; a spindle;-m eans journ-alling said B spindle in said carriage for rotation relative thereto; a tool holder for presenting said one end of a tool to a grinding wheel; means mounting said tool holder on said spindle for rotation therewith; a slide; means mounting said slide on said carriage for reciprocating movements relative to the latter along a path substantially normal to the path of movement of said carriage; a template having a pair of cam surfaces thereon; means mounting said template on said slide for movement therewith; means reacting between said base and one of said cam surfaces during movement of said slide for imparting movement to said carriage; means reacting between the other cam surface and said base and including a connection to said spindle for imparting rotation to said spindle during movement of said slide; and means connected to said slide for moving the latter.

2. Apparatus as set forth in claim 1 wherein the means mounting the template on said slide are removable for enabling any one of a number of different templates to be used so as to producea number of tools having different profiles.

3. Apparatus as setv forth in claim 1 wherein said means reacting between said base and said one cam surface includes support means mounting said support on said base, and a cam follower mounted on said support in engagement with said one cam surface.

4. Apparatus as set forth in claim 3 wherein the mounting means for said support is adjustable relatively to said base.

5. Apparatus as set forth in claim 1 wherein the means reacting betwen said base and said other cam surface includes slidable plunger means, and means for urging said plunger means towards said other cam surface.

6. Apparatus as set forth in claim 5 wherein the end of said plunger means adjacent to said other cam surface carries a roller.

7. Apparatus as set forth in claim 5 wherein said plunger means comprises a pair of toothed rack elements having their teeth in mesh with teeth on said spindle, one of said rack elements being in engagement with said urging means and the other being in engagement with said other cam surface.

8. Apparatus as set forth in claim 5 wherein said connection to said spindle includes a flexible band having one end anchored to said plunger means and its other end passing around and anchored to said spindle, and another flexible band having one of its ends anchored to said plunger means and its other end passing around and anchored to said spindle, said bands extending in an opposite direction from said spindle and being oppositely passed around said spindle.

9. Apparatus as set forth in claim 1 wherein the tool holder mounting means includes a crank arm fixed to said spindle and extending radially therefrom, and an indexing device secured to said arm and to said tool holder.

10. Apparatus as set forth in claim 9 wherein said tool holder is so supported by said indexing device and said arm that a tool held in said tool holder may have its said one end located at and rotated about a point substantially on the axis of rotation of said spindle.

11. Apparatus as set forth in claim 9 wherein said indexing device comprises a shaft journalled on said arm, one of the ends of said shaft having an eccentric thereon in engagement with said tool holder, and means connected to said shaft for rotating the latter, said eccentric bearing against'said tool holder to effect relative movement of said tool holder and said arm.

12. Apparatus as set forth in claim llwherein the was jar-verifies sai s-shaft, i lu es a rat he were;

pori'ings'aid"emiage'for reciprocating move car along a path towards and away from a grinding station; a slide; means supporting said slide on said carriage for reciprocating movements of the slide along a path substantially normal to the path of said carriage; a spindle; means mounting said spindle on said carriage for rotation relative thereto; a tool holder; means mounting said tool holder on said spindle for rotation with the latter; means connected to said slide for effecting reciprocating movements thereof; a template having a pair of opposed cam surfaces thereon; means mounting said template on said slide; a first cam follower mounted to follow one of said cam surfaces; a second cam follower mounted to follow the other cam surface; and means connecting one of said cam followers to said spindle for translating movement of said one cam follower into rotation of said spindle and said tool holder. I

15. Apparatus for grinding one end of a tool to a predetermined profile comprising a base; a carriage mounted on said base for movements along a reciprocating path relative to said base; a spindle; means journ-alling said spindle in said'carriage for rotation relative thereto; a tool holder for presenting said one end of a tool to a grinding wheel; means mounting said tool holder on said spindle for rotation therewith; a slide; means mounting said slide on said carriage for reciprocating movements relative to the latter along a path substantially normal to the path of movement of said carriage; a template having a pair of cam surfaces thereon; means mounting said template on said slide for movement therewith; a first cam follower; means mounting said cam follower to follow one of said cam surfaces; a second cam follower; means mounting said second cam follower to follow the other cam surface; means connecting one of said cam followers to said spindle for translating movement of said one cam follower into rotary movement of said spindle and the tool holder; and means connected to said slide for moving-the latter.

16. Apparatus as set forth in claim 15 wherein said one of said cam followers comprises a plunger mounted for reciprocating movement.

17. Apparatus as set forth in claim 15 wherein the means connecting said one of said cam followers and said spindle comprises a flexible band having one of its ends anchored to said plunger and its other end passed around and anchored to said spindle, and another flexible band having one of its ends anchored to said plunger and its other end passed around and anchored to said spindle, said bands extending in opposite directions from said spindle and being passed in opposite directions around said spindle.

18. Apparatus as set forth in'claim 16 wherein the means connecting said one of said cam followers and said spindle comprises teeth on said plunger and corresponding teeth on said spindle.

19. Apparatus for grinding one'end of a tool to a predetermined profile comprising a base; a housing supported on said base; a carriage mounted on said base within said housing for reciprocating movement along a path fore and aft of said base; a spindle journalled in said carriage for rotation relative thereto; a tool holder; means mounting said tool holder on said spindle for rotation therewith; a slide mounted on said carriage for reciprocating movement along a path substantially normal to the path of movement of said carriage; a template having a pair of opposed cam surfaces thereon; means mounting said template on said slide for movement therewith; a first cam follower mounted in said housing for engagement with one of said cam surfaces; a second, cam follower slidably mounted in said carriage for engagement with the other cam surface; means connecting said second cam follower to said spindle for translating sliding movement of said second cam follower to rotary movement of said spindle; and means connected to said slide for elfecting movement of the latter relative to said cam followers.

References Cited in the file of this patent UNITED STATES PATENTS