US2218716A - Drill fluting machine - Google Patents

Description

Oct. 22, 1940. H. E. MATTHEWS DRILL FLUTINGMACHINE Filed Feb. 25, 1958 4 Sheets-Sheet l JQveor: @Hanf-@Maya Oct. 22, 1940. H. E. MATTHEWS l DRILL FLUTING MACHINE sheets-sheet 2 Filed Feb. 23, 1938 Oct. 2 2, 1940.` H. E. MATTHEWS DRILL FLUTING MACHINE 4 sneetssheer s Filed Feb. 2s, 1938 H mm von il@ m @@n@ OLV@ C Oct- 22, 1940. H. E. MATTHEWS DRILL FLUTING MACHINE Filed Feb. 23, 1958 4 Sheets-Sheet 4 Alli Patented Oct. 22, 1940 DRILL FLUTING MACHINE y Harlan E. Matthews, Buchanan, Mich., assignor to Clark Equipment Company, Buchanan, Mich., a rcorpoiation of Michigan Application February 23, 1938, Serial No. '191,992

` 13 Claims.

This invention relates to a drill fluting mechanism, and more particularly is directed toy apparatus of a semi-automatic nature for forming the flutes in small drill blanks and the like by 5 the use of a single formed milling cutter in place of the two conventional formed cutters mounted angularly to each other andv to the drill blank.

It has been difficult, in previous types of mechanisms for forming iiutes in drills, to obtain accurate formation of these flutes due to the impossibility of producing two formed cutters of exactly the same contour and because of the inability of an operator to so adjust two cutters in angular relationship to each other and to the drill being cut Vas to produce a drill of absolute uniformity. v k

It has also been customary, so far as I am aware, to form the flutes in small drill blanks by means of hobs or the like, and the size of the blanks was such that inaccurate fluting occurred. So far as I am aware, no one has attempted to form such utes by means of feeding a drill through automatic feeding mechanism to a rotating cutter with automatic means for indexing the blank from the cutter, reindexingthe same,v

again feeding it to the cutter and then again returning it from cutting position and declutching the drive mechanism. This therefore requires the attention of an operator only for the insertion of a drill blank into the mechanism, and the removal of the fluted blank therefrom. One -operator is therefore capable of supervising the operation of a plurality of such mechanisms, which greatly reduces the cost of the drills.

One of the primary objects of the present invention is to provide means fory gripping the drill blank in projecting position and then feeding the same along a predetermined helix whereby it is moved axially and simultaneously rotated asit passes into engagement with the cutter. A suitf able clutch mechanism is provided for stopping the forward movement of the blank at apredetermined point and simultaneously raising the drill cutter out of engaging position. The blank is then returned, reindexed for the second flute and again fed into the cutter whereupon the clutch means again operatesto return y.the blank the drill so that the flutes are formed at pre- (Cl. S-15.1)

to initial position and simultaneously declutches the actuating means.

One of the features of the present invention is the provision of a lifting cam associated with thev cutter for producing simultaneousraising movel5 ment of the cutter as the drill is fedthereto, thereby producing the desired ,decrease in depth of the flute as itapproaches the shank portion of the drill. This same camming mechanism operates to raise the cutter out of engagement with 10 the blank as the machine reverses for the re- 'n indexing operation.

Another advantage secured by the present invention is Athe provision of a cutter so mounted with respect to the axial direction of the blank 15 that the center of rotation of the cutter shaft4 always lies in a vertical plane throughk the axis l f of the blank, although the cutter itself may assume any desired angularity with respect to this blank. v

`Still another feature of the present invention is the provision of a clutch mechanism for clutching the blank feeding means to a prime mover such as an electric motor orthe like, which is automatically disengaged upon the completion of k25 a predetermined number of flute forming` operations.

Still another feature of the present invention is the provision of a driving shaft mounted upon eccentric bearing journals and controlled by a 3o friction clutch 4so that upon `the feeding mechanism reaching its inward limiting position, the clutch is released to allow a half revolution of the shaft journals, thereby placing theshaft in a laterally offset position in driving engagement 35 through a separate gear train to effect ,reverse kmovement-of thefeeding mechanism for Withdrawing the blank from cutting position and re-` indexing the same.

Still another object of the present invention is 40 to provide acamming mechanism operable upon' return of the feeding mechanism to initial position for releasing the indexing engagement em- -ployed in ther first flute forming operation, and f automatically. reindexing the mechanism for 45 forming the second flute.

Another feature of the present invention is the absolute uniformity of the completed drill, obtained by cutting each flute with the same cutter, thus producing twoflutes exactly degrees 50 apart with the web or solid central portion of the drill in the exact center of the drill blankregardless of the setting of the cutter in relation .to-the drill. An advantage of the above feature is that owing to the uniformityiof the amount rof metal 55 :removed from the flutes of the drills by the milling operation, they suffer much less distortion during the extreme high heats necessary in the hardening and drawing operations, with resultant saving in subsequent straightening operations.

Another feature and distinct advantage of the present invention is the provision of means for effecting relatively high speed reverse movement of the feeding mechanism while yet effecting the proper relatively slower feeding speed during the flute forming operation.

In connection with this latter mechanism, I provide a second clutch operated by the feeding mechanismas it reaches its outer limiting position for effecting a half revolution of rotation of the eccentric bearing journals of the main driving shaft, thereby restoring the original gear drive for producing inward movement of the feeding mechanism.

Another feature of the present invention resides in the provision of a stop means operated by the feeding mechanism for de-energizing the entire machine in the event that the clutch for reversing the movement of the feeding mechanism fails to operate.

Still another feature of the invention resides in the provision of a lubricating pump operated by the same prime mover that operates the feeding mechanism, and which forces lubricant over the cutter and drill blank during' the cutting operation.

Other objects and advantages of the present invention will be more apparent from the following detailed description Which, taken in conjunction with the accompanying drawings will disclose to those skilled in the art the particular construction and operation of a preferred form of the present invention.

In the drawings:

Figure 1 is a rear perspective view of the essential portions of the drill fluting mechanism;

Figure 2 is a front perspective View of the mechanism shown in Figure 1;

Figure 3 is an end perspective view of the driving mechanism and feeding means;

Figure 4 is a diagrammatic view showing the gear relationships of various portions of the mechanisms; and

Figure 5 is a sectional view taken substantially on line 5 5 of Figure 4 showing the indexing mechanism.

Referring now in detail to the drawings, the base of the machine is shown generally at Ill and mounted thereon is an electric motor I2 as shown in Figure 2. This motor is provided with the double pulleys I3 and I4 mounted on the drive shaft thereof, the pulley i3 being connected through the belt I5 to a large pulley It mounted on the end of a shaft il which is supported in suitable journals I8 and I9 for rotation.

The operation of the motor I2 is controlled through means of the switch 23 shown inFigure 2 and mounted on a suitable pedestal 22 secured to the base I0. Mounted on the shaft I I is a small pulley 23 adapted to drive the belt 24 connected to the drive shaft 25 of a lubricant pump indicated generallyv at 26. The lubricant pump 26 has its inlet 21 connected to the base of the center supporting pedestal 28 and has an outlet connection 29 which, through the conduit 30 and valve 32, is adapted to supply cutting oil to the cutter 33.

From the cutter 33 the oil trips into the sump 34` from which it is drained through the spout 35 into the base of the stand 28 and then returns to the inlet of the pump 25. The shaft Il extends through a clutch housing 36 and is provided with a small pinion gear 3l Within the housing. The housing is also adapted to provide a rotatable support for a countershaft 38 upon which is mounted the gear 39 driven from the pinion gear 31. A similar pinion 45 on the shaft 38 is adapted to drive back to the gear 42 which is free for rotation on the shaft Il. An output shaft 43 extends through the opposite side of the housing 36 and is provided with a suitable clutch collar M connected to the clutch operating lever 45 for axial movement on the shaft Il@ into and out of engagement with the clutch teeth 46 carried by the gear 42. Consequently, a double reduction of the drive from the shaft Il' to the shaft 43 is effected through the clutch d4 connected to the lever 45. The lever 45 is mounted for rotation about a pivot 4l and at its upper end is provided with a handle portion 48 adapted to be controlled by the operator. The lower end of the lever beneath the pivot fil is provided with an ear 49 receiving one end of a tension spring 50, the 4opposite end which is secured to a fixed part of the stand i l) (not shown).

A suitable arm 52 is pivotally mounted on the top of the clutch housing 36 by meansof the stud 53, and is provided with the spring 54 normally urging it against the lever 45 so that it follows the lever when the lever is shifted into clutch position. The arm 52 is held against reverse rotation about the stud 53 by means of the pivotally mounted latch 55 which has a lug 55 adjacent one end thereof adapted to engage in a suitable detent in the arm 52 to prevent reverse rotation thereof. A suitable leaf spring 5l normally holds the latch 55 in position to effect locking of the arm 52 against movement after the clutch has been shifted into clutch position.

The end of the shaft I3 is provided with the sprocket wheel 6I! which is connected through the sprocket chain 62 to a second sprocket wheel 63 carried on the main driving shaft 64, as shown more clearly in Figure 3. Mounted on the outer side of the sprocket wheel 6D is an idler arm 65 carrying the sprocket idler 66 for maintaining the proper tension on the chain 62.

The drive shaft 64 is mounted in eccentric bearing journals indicated most clearly in Figure 1 by reference numerals 6l and 68 which are normally held against rotation by means of a friction clutching mechanism enclosed in subbase III, the details of which form no part of the present invention, and therefore it is not believed necessary to describe the same. The bearing journals 61 and 68 are mounted in a support 'II which is secured to the frame Il! in any suitable manner, and the amount of eccentricity is indicated by the difference in position of the center of the bearing journals as indicated at A and A' in Figure 4. A suitable connector plate 69 connects the journals 61 and B8 of the eccentric bearing assembly so that they are rigidly supported for conjoint movement upon release of the friction clutching mechanism. A relatively small diameter driving gear of considerable axial extent is formed on the main shaft as inldicated at 10, and rotates on bearings within the journals 6'I and 68. Upon release of latches It!) and I6'I by means of the friction clutch, the pinion gear 'Hl will rotate with the eccentric journals v6'! and 68. Also secured to the main shaft is a large gear drum 12 keyed for conjoint rotation therewith.

Referring now in more detail to Figures 3 and 4, it will be noted that when the pinion 10 is in a position such that its center is rotated, as indicated at A in Figure 4, the'drum gear 12 isin meshing engagement with an idler gear 13 mounted upon shaft 14, which in turn meshes with an intermediate gear 15 mounted upon shaft 15 that, at itsI opposite side, is in meshing engagei ment with a drum gear 11 mounted on a shaft 18. The drum gear is adapted torotate in the direction indicated by the arrow in Figure 4, and consequently produces clockwise rotation of the gear 11. It will be noted that the shaft 18 is supported on a suitable journal 1B and is provided adjacent its outer end with a bracket 19 adapted to supporta pivot pint@ mounting the latch releasing lever 82 thereon. The lever 82 is in the form of a bell crank, .one end of which, indicated at 83, extends between the forked end lever 55. This same journal 1B extends downwardly and forms an end journal for the outer ends of the shafts 14 and 15 as clearly shown in Figure 3, and is also supported upon the base or frame I0. y

When the gear member 12 is'in itsy opposite position, thatv is, when its center is at a point indicated at A' in Figure 4, it is adapted to have meshing engagement with the indexing gear 85 carried on the spindle 85. It will also be noted that the gear 11 is at all times inV meshing engagement with the feed gear V81 which is connected to a sleeve 8B extending through a longitudinally projecting journal 89 formed ladjacent the top of the stand 28 as shown in Figures l and 2. The feeding sleeve 88 is provided with a spiral thread or recess 90, the pitch 4of which forms the lead for the blank, The sleeve88 is moved longitudinally within the journal 89 by the engagement of a bronze pin therewith within the journal 89, the pin being formed at the end of the stud 92 which is supported in the boss 93 formed on one lateral side of the journal.

Considering nowagain Figures 1 and 2, it will be noted that the spindle 86 extends through the sleeve 88 and at its opposite end is provided with a collet portion 94 containing gripping jaws for gripping the drill blank 95. These jaws are actuated by the knurled spindle 95 lat the opposite end of the collet 94 which is rotated in one direction to tighten the drill in position, and is rotated in the opposite direction to loosen the drill for removal. Y

Mounted on the frame I0 is a bar member 98 having an elongated slot 99'therein whereby it may be longitudinally adjusted with respect to the frame by means of the locking nut |00. The arm 98 has a vertically extending portion |02 which, at its upper end is provided with a pin |03 adapted to receive at the inner end thereof the camming arm |54 having the cam surface |05 secured thereto. This arm is rnounted'forv pivotal movement with respect to the arm portion |02 and is normally restrained in the position shown in Figures 1, 2 and 3 by means of the tension spring |55 secured to the arm and to the arm portion |02. The gear 85 is provided with two indexing plungers |91 and |08 mounted in cylindrical supports |09 threaded into suitable openings in the gear 85 and indicated in detail in Figure 5.V The plungers |51 and H08 have reduced portions I I0 projecting through the gear 85 and normally urged outwardly therefrom bymeans of the spring |12,

Th'ege'a'r' 81y is provided 'with acooperating indexing plunger. l |4mounted ina support I 5 extendingithrougl'i the gear 81 .and clamped thereto by the nut` I I6 en-gaging the projecting threaded shank.` A suitable spring I I1 retained in the axial recess inthe support.l |5 normally urges the plunger ||4 toward the gear 85 The projecting end I I8 ofthe plunger I |4, when in indexed position is adapted to extendinto the recess or bore of one of the supports |09 and contacts the inner end of the plunger 01; f

However, whenthe rotation of the gear 85 is such as to forcethe projecting ends of either the plunger |01 or |00 inwardly by engagement with the cam surface |05`of the arm |04, the plunger is forcedinwardly. into position to disengage the projecting'end H8 ofthe plunger ||4 from the gear 85.` As a result,v the gear 81 is released for relative rotation with respect to the gear 85, and the gear 85 is adapted to move into position to bring the opposite plunger opening Ithereof into alinem'ent with the plunger endl I8 of the plunger I4, Since cam member |04 swings back, this end immediately enters into the recess formed in the support |09 and ythus locks the two gears 85 and 81 together for. conjoint rotation into angular relationship'of 180 degrees with respect to their initially locked position.'

Whenever the two gears 85 and 81 are locked together thesleeve 88 will produce longitudinal movement of thexspindle 86 upon rotation of the gear 81 since the spindle and sleeve are correspondingly locked `together for conjoint rotation. Consequently, the longitudinal movement of the sleeve 88 will produce a corresponding axial movement of the drill blank 95,. either into or out of engagement with the cutter 33.

Reference is now made to Figures 1 and 2A to show the mounting of the cutter mechanism for forming the fluted end in the drill blank. A post (not shown) carrying the hardened drill guide (not shown) at its upper end extends vertically through lthe base I0 to the upper end (immediately below the drill bushing) to which is secured the sump 34 surrounding the cutter mechanism. This post has mounted thereon a sleeve |20 carrying 'at the-lower end and integral with it the graduated flange |34 which is secured by clamping screws |35 to the base I0 butvis otherwise free to rotate about the cutter post. Mounted upon sleeve |20 is the member |22 which has a sliding fit on sleeve |20 and is prevented from rotating with respect thereto by the key |32 which engages a' slot (not shown) in sleeve I 20. The member |22 is free to move axially on sleeve |20 but is normally held in contact with cam bar |44 through the lateral .extension |49 and the spring 43. Integral with the member |22 is vthe web I2@ carrying at its lower end the transverse shafts |25 upon the opposite ends of-which are mountedthe pulleys |26- Adjacentto its upper end the web |24 provides `a support for the longitudinally extending journal |21 through which extends the shaft 28 having the pulley l29 secured thereto above the pulleys |25. At its opposite end the shaft E28 is provided with `a suitable adjusting clamp ynut for n angle of the cutter`33,"the member |22 may be rotated with respect tothe center line of the drill by loosening the clamp screws |35 in the flange plate |36 carried by the sleeve |28 and relocating the cutter mechanism by the angular graduations on the ange |34. The pulleys |26 and |29 are adapted to be engaged by a driving belt |31 which is trained thereof and which extends beneath the base plate I and under the pulley wheel |38 to the second pulley I4 on the motor drive shaft of the motor I2. Thus, the shaft |28 is driven from the motor I2v conjointly with the drivingl mechanism including the shafts |1 and 43.

It will be noted that the lower end of the member |22 is provided with a flange portion having the lateral extension |48 forming a pair of ears between which is clamped a lifting plate |42 normally engaged by a spring |43 for pulling the member |22, and consequently the shaft |28 downwardly to locate the sameY with respect to a cam plate or lifter |44. 'Ihe lifter |44 is longitudinally tapered and is forced beneath the plate |42 by movement of the gear 81 to produce raising of the cutting mechanism as the feeding mechanism feeds the blank thereto so that the depth of cut of the flute is slowly decreased as the blank is fed into the cutter. The cam arm |44 is connected to a cross head |45 which has an extending shaft |46 supported by the journal (not shown)r inside of the stand 28. The shaft |46 projects through a suitable journal inside of stand 28 and has a projecting end portion 58 adapted to be engaged by the lateral face of the gear 81. The projecting portion |58 is provided with a serrated surface on one lateral face thereof which is adapted to be engaged by the rocking surface of a locking member |52 in the form ofv a bell crank pivotally mounted on the side of the stand 28, and having its other arm portion extending down beneath the pinion and cross section 69 in such manner that when the eccentric bearings 61 and 68 are released so that the member 68 rotates to its lowermost position, it rocks the arm |52 into pressure engagement with the serrated surface of the shaft to lock the cam member |44 in xed position against the tension spring |55 which is connected between the cross head |45 and a fixed portion of the mechanism.

Mounted on a bracket |56 projecting from the side of the stand 28 is a safety switch mechanism enclosed within the housing |51. This mechanism has a plunger |58 projecting therefrom toward the gear 81 and is adjustable with respect to the gear 81 by means of the adjusting screw |59 carried by an upwardly extending arm portion |66 of the bracket |56. This safety switch mechanism is for the purpose of shutting off the motor I2 if the gear 81 should move beyond a predetermined position determined by the length of flute to be cut in the drill blank. It will be noted from Figures 1 and 2 that a plunger |85 is provided projecting from the end face of the sub-base |1|, and which is disposed in the path of movement of the gear 81. This plunger |65 is for the purpose of operating the friction clutch controlling the locking of the bearings 61 and 68 in alternate positions. When the gear 81 engages the plunger which forces the same slightly inwardly, the latch is released and the bearings 61 and 68 and member 69 rotate through a half revolution to move the pinion 10 out of engagement with the gear 81 and downwardly into position such that the gear drum 12 engages the gear 13. 'I'he return of the bearings 61 and 68 to their initial position is provided by engagement of the gear 81 with the adjusting knurled nuts |61 carried on a shaft |68 disposed "out of the peripheral path ofthe gear 81 with the edge of the gear engaging the nuts |61 to move them to the left as shown in Figure 1, thereby drawing the shaft |68 to the left and consequently again releasing the friction clutch to allow the bearings 61 and 68 and the pinion shaft 58 to rotate through part of a second half revolution into almost their initial position, thereby placing the gear 85 in mesh' with the gear drum 12.

Considering now the operation of the mechanism when it is desired to ute a gear blank, the motor I2 is first started by means of the control switch 28. This produces rotation of shaft |1 and also rotation of the cutter shaft |28 through the belt drives I and |31. A drill blank 95 has been locked in the collet 64 by rotation of the knurled locking spindle 86, and the mechanism is disposed with the sleeve 88 in its outerthe plunger ||8 in the recess of the support |89 of the gear 85.

The clutch 48 is then rotated from the position shown in the drawings into a position to engage the clutch collar 44 with the clutch teeth 46 of gear 42. 'I'his produces rotation of shaft and consequently, rotation ofthe sprocket wheel 63 in a counter clockwise direction. This produces counter clockwise rotation of the gear drum 12, and consequently, clockwise rotation of gears 85 and 81. The eccentric journals 61 and 88 are at this point in an intermediate position, with gears 10 and 81 out of engagement.

However, the gear 85 soon leaves the gear drum 12 due to the forward travel of sleeve 88 by engagement of the pin 92 in the thread 68. As a result, the eccentric journals move up to limiting position, rotating pinion gear 18 into mesh with gear 81 to drive the gear 81 for feeding the drill blank 95 into the cutter 33. During this time the pump 26 is pumping suitable lubricant over the cutter through the conduit 38, and this lubricant is being drained into the base of the stand 28 and returned to the pump. The gear 81 at the same time is in mesh with gear 11 and consequently rotates the gear vtrains 11, 15 and 18.

However, since the drum gear 12 is out of engagement with gear v13, this gear train merely idles during the feeding operation. As the gear 81 nears the 4end of the feeding movement the lateral face thereof engages plunger |65 forcing the same inwardly, and thereby releasing the friction clutches holding bearings 61 and 68. These bearings are then free to rotate, and consequently rotate the pinion 18 and gear drum 12 into a position having a center of rotation indicated at A in Figure 4. As a result, driving engagement of the pinion with the gear 81 is released and no further feeding movement is produced.

During this feeding movement, the lateral face of the gear 81 has also been forcing the shaft |50 to the right as viewed in Figure l, consequently forcing the camy |44 beneath the plate |42 to progressively raise the collar |22 and consequently decrease the depth of flute being cut. As the bearings 61 and 68 are released by the operation of plunger |65, the rotation of the pinion 18 and member 69 into the lower position rocks` the bell crank |52 into position to engage the serrated plate in position to maintain the cutter Mheaddn raised position. It should be vpointed outthat the rear portion of the cam bar |44 hasan increased taper so that a-s the end of the feeding movement is reached, the cutter head is raised to an extent so as to remove the cutter entirely from the drillblank.

With the mechanism in this position, the rotation of the eccentric bearing journals into lowered position forces the drum gear 12 into engagement with the gear 13 and consequently kdrives the gears 15 and 11. This results in clockwise rotatio-n of the gear 11 which, being in lconstant en1.

gagement with gear 81, produces counterclockwise rotation of gear 81, and moves the :feeding sleeve 88 in the yopposite direction to movethe collet 84 Aand drill blank 95- back towardv their initial position.

As the gears 85 and 81, which are still-locked released for relative rotation with respect to the gear 81, the gear 81 engages the nuts |61 to actuate control shaft |68 for releasing the eccentric bearing journal clutch andallowingthe pinion shaft and drum gear to rotate back toward the position indicatedat A' in Figure 4. As aresult,

the drum gear 12 moves into meshing engagement with gear 85, and rotates this gear inthe opposite direction; that is, `a counterclockwise direction, thereby bringing the plunger |81 into alinement with the plunger I8' f whereby the plunger i i8 moves into the-opening in the support |88of the plunger |81 to again lock the gears 85 and 81 together. During this time, the gear 85 is being driven by the drum gear 12 in a feeding direction, and due to the rotation -of the gear85, the plunger |81 moves into different alinement to produce the locked position indicated in Figure 5.v

At this instant the gear 85 drops off of the drum gear `12, allowing the eccentric journals to movel into full upper position, and the mechanism feeds forwardly at a slow rate, being driven fromfthe pinion 18 and the gear 81. The rotation o-f the bearings has also produced disengagement ofthe drum gear 2 from the gear13 so that the gear 81 merely rotates theY gears 11,'15 and 13 idly about the shafts as the feeding movement progresses.

It should also be remembered that as the eccentric bearing journals rotate from their lower to their upper position they release the lower end of the bell crank |52 Awhich in turn disengages the upper portion of this bell crank from the serrated surface of the shaft |58, thereby allowing spring |55 to draw the cam bar |44 back to a position lowering the cutting mechanism into proper position for engaging the end of the drill blank. The mechanism then again feeds forwardly to form the second flute in the drill blank in the same manner as previously described.

As the plungerl |65r is engaged by the gear 81, the bearings again rotate to their lower-most position, and the gear 81v is reversed and driven in a counter-clockwise direction by the gear 11 which is driven from the drumkgear 12. However,

` this time when the plunger |81 engages the cam face |85 and thereby releases the locking engage- 2,218,716 surface of the shaft |58V and thus locks vthe cam ment, by the gears 85 and 81, the'return of the bearings toward'their upper position produced .by engagement of gear 81 with shaft |68"results in the pin |18 moving in a clockwisedirectionvand engaging the upwardly extending portion |12 of the bellicrank-BZ, thereby vrocking the bell crank inv a clockwise direction about the pivot 88 to lift .the locking end of the lever 55 from engagement -with arm 52. r-Ihis releases the rocking engagement of the clutch 48,' andthe spring 58 is then effective to move the lever 155 back into the open vposition sho-wn inv Figure 1. This disengages the drivingmechanism from the power shaft, and consequently ystops the feeding mechanism so that lthe drill may be removed and a new drill inserted.

yIf; vfor any reason, the friction clutches controlled by the plunger |65 and shaft |68 should.' vfail to operate and the feeding mechanism should continue feeding the drill toward the cutter, the gear 81 wilhengage the plunger |56, therebtr breaking contact between the conductors enclosed within the cable |13 leading to the control switch 28 andwill stop the motor l2 so that no damage tothe mechanism .will occur. This is merely* a safety feature to prevent overdriving of the feed mechanism in case the friction clutchescontrolling-the eccentricv bearings should fail to operate. It is thereforev believed apparentthat I have provided a mechanism which is automatic in operation after the drill blank has once been locked 1in position until completion of the fluting .operation. Thus an operator is able to supervise the operation of a plurality of such/machines since the only work required is the inserting and removall of the drill blanks, as the rest of the operations -are all automatically controlled by Vthe mechanism herein disclosed.

Of course I amaware that a number of changes vmay be made in certain details of construction of portions of the ,presentmechanism without in lany way departing from the underlying principles thereof,` and I therefore do not intend to be limited except as dened by the scope and spirit of the appended claims.

` I claim:

' l. In combination, a rotating flute cutter, a rspindle adapted Ato have a drill blank locked in one end thereof, a feeding sleeve surrounding said spindle, means -for selectively indexing and lock` ing said sleeve to said spindle for conjoint rotation therebetween to feed said blank to said cutter, and means forreversing the rotation of said isleeve upon predetermined feeding movement lment with said feeding means.

3. In combination, in a kdrill fluting mechanism, a main power shaftv includinga pinion and a drum gear mounted on eccentric bearing journals, feeding means driven by said pinion, reversing means driven by said drum gear, and clutch means controlled by predetermined movement of said feeding means forv releasing said power shaft formovement on said journals to move said pinion into vinoperative position and simultaneously' to move said drum gear into operative position. Y

4. The combination of claim 3 further characterized in the provision of means operated by said drum gear at the end of reversing movement of said reversing means for reindexing said feeding means.

5. In combination, in a drill fluting mechanism, a blank holding spindle, a coaxial feeding sleeve mounted thereon, a rotatable cutter for iluting the blank in said spindle, means supporting said cutter for vertical movement relative to the axis of said spindle, driving means, indexing means interlocking said sleeve and spindle for feedingV movement toward said cutter, and means controlled bymovement of said sleeve for simultaneously raising said cutter to decrease the effective depth of said flute Yas the blank is fed thereinto.

V6. In combination, in a drill fluting mechanism, a motor, a power shaft, feeding means for feeding a drill blank to a flute cutter, pinion means on said shaft for driving said feeding means, reversing means driven by saidshaft and automatically operable toI reverse said feeding means and reindex the same prior to a second feeding movement, means for clutching said motor to said shaft, spring means normally tending to disengage said clutch means, a latch for holding said clutch means in engaged position, and lever means actuated automatically upon the second reverse movement of said feeding means for releasing' said latch to effect disengagement of said clutch means.

7. In a feeding mechanism for a drill iluting machine, a spindle having a collet at one end for gripping a drill blank, anindexing gear on said spindle having circumferentially spaced axially projecting spring pressed plungers, a feeding sleeve coaxially mounted on said spindle and having a spiral groove in the external surface there-- of, a journal for said sleeve and spindle having a fixed pin engaging in said groove, a feeding gear vfixed to said sleeve and rotated in one direction for feeding said sleeve through said journal, a spring pressed plunger on said feeding gear adapted tointerlock selectively With said plungers on said indexing gear for locking said sleeve and spindle for conjoint rotation, and cam means selectively engaged by said spaced plungers on said indexing gear for indexing said spindle in different positions to said sleeve.

8. The combinationl of claim 7 further characterized in means for selectively clutching said feeding gear to a driving pinion and to a reversing train of gears to alternately feed said blank to a iluting cutter and to Withdraw said blank vfrom said cutter for reindexing said spindle with respect to'said sleeve.

9. The combination of claim 7 further characterized in the provision of a drive shaft having alpinion for forward driving of said feeding gear and movable laterally of its axis on eccentric -drum gearonsaid shaft disposed out of engagement with the other of said gears during driving engagement of said pinion, an idler train of gears in constant engagement With said one gear, eccentric journals for said drive shaft, and means holding said drive shaft in one position in said journals and releasable upon predetermined movement of said feeding means for moving said drive shaft to a second position to disengage said -pinion and move said drum into driving engagement with said train of gears for reversing the direction of rotation of said one gear.

l1. The combination of claim l further characterized in the provision of cam means for disvengaging said interlocked gears simultaneously with the return of said 'drive shaft to its first position to effect engagement of said drum gear with said other gear for reindexing said feeding means and interlocking said coaxial gears prior -to a second feeding movement of said feeding means. r 112. The combination of claim l0 further characterized in the provision of means on said other gear for releasing said clutch means upon the completion of the second reversal of said feeding means.

13. In combination, in a drill iuting mechanism having blank feeding means automatically -driven in a feeding direction and then reversed to Va non-feeding position, an indexing gear plunger means connecting said gear to said feeding means,

vcam actuated means responsive to nal reversing movement of said feeding means out of feeding position for releasing said plunger means to release said indexing gear for rotation. relative to said feeding means, and spring means engaging said plungers for reconnecting said gear after predetermined relative rotation into a reindexing position to said feeding means prior to initiation 0f the next feeding movement thereof.

HABLAN E. MATTHEWS.

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