Патент USA US2408917код для вставки
Oct. 8, 1946e A, (3201' BIT SHARPENER ‘Filed Oct. 6, 1944 2,408,916 . ' 2 Sheets-Sheet 1 - INVENTOR. ANDRE’ CROT Patented Oct. 8, 1946 UNITED STATES PATENT 0mm: 2,4Q8,916 BIT SHARPENER Andre Crot, North Hollywood, Calif, assignor to Lockheed Aircraft Corporation, Burbank, Calif. Application October 6, ‘1944, Serial No. 557,412 4 Claims. (or. 51-2s2) 1 This invention relates to special machine toolsg for machining helical surfaces of any desired pitch ‘ and relates more particularly to and ?nds its most frequent application to the forming and sharpening of spiral or helical cutting edges of tools such as drills, router bits, milling cutters, 2 dle and spindle drive shaft being constructed to snugly telescope to provide for limited axial re ciprocation with respect to one another and com mon rotation together. Common rotation of the spindle drive shaft I5 and the tubular spindle I4 is effected by means of a pair of keys it re tained in suitable recesses on the inside surface of the tubular spindle and adapted to slide axial ly within a pair of elongated key-ways l7 formed in the surface of the drive shaft IS. 10 ally employed for the purpose of resurfacing or The tubular spindle I4 is reciprocatably and sharpening spiral or helical cutting edges of drills, rotatably supported in a bushing l8 which is in router bits, milling cutters, reamers, and the like turn retained within a bearing support or bear tools, with the result that such operations were ing holder 19 which is inserted and suitably slow and inefficient and resulted in inaccurately bolted in place, as shown at 20 in an opening 15 shaped, poorly operating tools. 2| located through the wall of the forward end and reamers. Heretofore a manual manipulation of the tool with respect to a grinding stone has been usu It is an object of this invention to overcome of the housing In. ' the disadvantages of the manual method and As best shown in Figures 3 and 4 the tubular other methods heretofore employed for recondi spindle is provided with a ?ange 22 on its outer tioning and machining spiral or helical edged tools end to which may be bolted a chuck body as shown by providing an automatic machine for this pur 20 at 23. Any suitable chucking means may be em pose which will be accurate, e?icient and fast in ployed depending upon the type of workpiece or operation. tool to be machined but for convenience of illus The objects of this invention are attained in tration herein a split collet type of chuck is general by a machine capable of imparting, be shown and described. A split collet grip-assem tween limits, any desired one of an in?nitely 25 bly providing a plurality of radially positioned jaws is retained as a unit within the collet body reciprocation motions to a work piece such as a by means of an inwardly projected unitary shank drill, router bit, or reamer, whereby a cutting 25. A nut 26 having an inner tapered face is or grinding operation may be performed on such shown at 2‘! and serves upon tightening upon workpiece along any corresponding helical edge threads 28 of the chuck body to wedge the col variable combination of simultaneous rotation and or path having any desired pitch. These and other objects and features of nov let jaws 2ll into gripping position upon the ‘cy lindrical shank 29 of the tool to be machined. The inner end of the tubular spindle l4 within the housing If! carries a thrust bearing iii] which 35 lustrate preferred embodiments of the invention. comprises an inner cylindrical race 3! and outer Figure 1 is a perspective view of the general cylindrical race 32 and intermediate needle bear arrangement of the apparatus of the invention ings as shown at 33. At either end of the inner elty will be evident hereinafter in the description which, together with the following drawings, il in operative position. and outer races 31 and 32 thrust washers as Figure 2 is an end cross-sectional view taken shown at 34 and 35 are provided which abut at 4:0 online 2-—2 of Figure 3. one end against a collar 36 formed integral with Figure 3 is a cross-sectional side elevation of the spindle and at the other end against an ad the machine taken on line 3-3 of Figure 2. justable stop nut 31 which is in turn carried on Figure 4 is a cross-sectional detail of the chuck the inner threaded end of the tubular spindle. ing unit carried by the apparatus of Figure 3. A look nut 38 is provided for retaining. the Figure 5 is a cross-sectional View taken on line 45 thrust nut 31 in adjustment. ' 5—-5 of Figure '2. The spindle drive shaft [5 which telescopes into Figure 6 is a detail view of the stop plate taken the bore of the spindle M is rotatably supported on line 6-—6 of Figure 3. in a bushing Ml which is retained in a suitable Referring now to the drawings in which like opening in the end of the housing iii in coaxial reference characters refer to corresponding parts throughout the several ?gures, the apparatus of the invention is as follows: A housing In is provided for enclosing the major elements of the machine, said housing having ‘a removable top i I normally held in place by means of a pair of machine screws i2 and I3. Extending lengthwise through the upper por tion of the housing is a composite shaft com prising tubular spindle M and a coaxially posi tioned spindle drive shaft l5, said tubular Slim alignment with respect to the beiorementioned bearing holder l9 and bushing l8. As herein before stated the drive shaft [5 is of such a size as to make a snug sliding ?t within the bore M of the tubular spindle I4, whereby said tubular spindle may be reciprocated With respect to said drive shaft through bushing iii. .A spur gear 48 is keyed at 42 to the drive shaft I 5 adjacent the inner surface of the rear end of the housing. A hub member 43 is keyed at 44 and retained in 2,408,916 3 adjusted axial position on the outer exposed end of the drive shaft I5 by means of a set screw 45. The inner ?ared end 48 of the bushing .40 acting against the hub of the gear £8 and the washer 41 acting intermediate the housing and the adja cent surface of the hub 53 serves to restrain the spindle drive shaft against axial movement with respect to the housing. 4 within a corresponding slot as shown at 04 formed in the lower surface of the housing or outer race 32 of the needle thrust bearing 30. The nut 80 and the needle bearing housing 32 are thus secured against rotation. The lead screw nut 80 is provided with a pair of coaxial oppositely extending trunnions as best shown at 85 and 86 in Figure 2 and the needle . An operating lever or handle 50 extends radi thrust bearing housing 32 is similarly provided ally from the hub 43, said handle comprising an 10 with a pair of coaxial oppositely extending trun inner shaft 5I and an outer axially movable tu nions as shown at 81 and 88. The trunnions 85 bular slide 52. The inner handle shaft 5I is ?xed and 86 of the lead screw nut are each pivotally in radially extending position with respect to the carried in square cross-head members ‘I9 and 88 hub 43 by means of threads and lock-nut as and the trunnions 81 and 88 of the needle thrust shown at 53 and 54 respectively. 15 bearing housing 32 are similarly pivotally carried The tubular handle slide 52 is slidable or re in square cross-head members 90 and BI. ciprocatable upon the handle shaft 5| within the A pair of oppositely positioned walking beam limits set by the stop nut 64 against the force of members 92 and 93 are pivotally supported at a the helical spring 55. The helical spring 55 act point intermediate their ends by means of a pair ing under compression normally retains the tu 20 of pins or bolts as shown at 95 and 96 which are bular handle shaft in a maximum outward po in turn carried in the inwardly extending ends of sition against the stop nut 64 on the end of the a pair of adjustable supporting arms 91 and 98. handle shaft whereby an offset latch member 56 Each of the walking beams is provided with a pair carried at the lower end thereof and movable of elongated slots or slides as best shown at I00 radially in a slot 56' in the hub 43 will normally 25 and IOI in Figure 5. The inner longitudinal sur be retained in locked position within a radial faces of the slots I00 and If“ serve as guides in locking groove 63 which is formed in the rim 5‘! which during the operation cross-head members of a circular stop plate 58 which is in turn ad 90-—9I and 19-89 slide. justably supported from the outer face of the The arms 9‘! and 98 are movably supported rear end of the housing by means of a pair of 30 upon a cross-shaft I02 to which they are keyed suitable machine screws as shown at 58 and 50. as shown at I03. The cross-shaft I02 is pivotally A pair of semi-circular slots 61 and 82 as best supported in a pair of oppositely positioned shown in Figure 6 provide for angular adjust bushings I05 and I06 located within the side walls ment of the stop plate for suitable angular posi of the housing. The cross-shaft I02 is adapted tioning of the lock groove 63 as desired. 35 to be adjustably rotated by means of a lever I01 Enclosed within the lower portion of the hous which carries at its outer end a pointer I08 adapt ing I0 is a lead screw shaft 65 rotatably sup ed to move over a graduated scale I09 carried on ported with its axis parallel with the axes of the a scale plate H0. The adjustment lever I0"! ‘is before described tubular spindle and drive shaft, adapted to be ?rmly retained in a given adjust in bushings 66 and 61 which are in turn re 40 ed position with respect to the scale I 09 by means tained in the walls of the housing by means of of a knurled nob III the shaft of which extends the bearing holders 63 and 69. A spur gear 10 through the outer end portion of the lever as meshing with the beforementioned drive shaft spur gear 48 is keyed to the lead screw shaft as shown at ‘H and adjustable to a limited degree axially thereon by means of a set screw 72. A collar or abutment 13 is formed integrally with the lead screw shaft and axial motion or play of the lead screw and the lead screw shaft 55 is limited by the abutment of the said collar 13 against the inner ?ared end 14 of the forward bushing 66 and the contact of the hub of the spur gear 10 with the inner surface of the inner ?ared end 15 of the rear bushing 61. The lead screw shaft 65 carries at an interme diate section and formed integral therewith a ground and polished lead screw having a plu rality of threads of suitable pitch as shown at ‘l6.v A nut 00 having internal threads is threaded on the lead screw '26 and is adapted to axial movement upon rotation of the lead screw shaft 65 as hereinafter more fully described. As an example, a %—6, 60° stub tooth lead screw hav ing a major diameter of approximately .875 inch, a minor diameter of .724 inch, a pitch diameter of approximately .80 inch, and a lead of T55 inch was satisfactorily employed in a machine of the type illustrated. The mating nut 80 is provided shown at II 2, and makes threaded connection with a threaded nut which moves in an arc in an internal arcuate recess II3 formed on the inside face of the scale plate H0. Angular displacement of the adjustment lever I051 serves to move the adjustment arm 91 through a corresponding angle which in turn, acting through the pins or bolts 95 and 96, serves to shift the walking beam 92 longitudinally with respect to the cross-heads 19-89, 90——9l. A flexible leather boot II5 ?xed to the spindle ?ange 22 by means of a clamping wire I I6 and retained in rotatable ?t in an annular groove II‘! in the outer end of the bearing holder I9 by means of a snap ring H8 serves to prevent for eign matter from entering the bearing surfaces between the spindle shaft I 4 and the bushing l8 which at the same time provides for rotational and reciprocative freedom of the spindle shaft with respect to the apparatus housing I0. The operation of the apparatus is as follows: The drill reamer, router-bit, or the like tool which it is desired to sharpen, is inserted into the collet chuck as best shown in Figures 1 and 4. The rotating cutting wheel I20 powered by suit able means such as an electric motor, not shown, with an upwardly extending elongated guide is adjusted into position where, for example as tongue 8I. The guide tongue‘SI is solidly ?xed 70 illustrated in Figure 1, a router bit is to be sharp within a slot 82 formed in the upper side of the said nut 80 and is held therein by means of three countersunk machine screws as shown at 83. The upper, elongated portion of the guide tongue enters and makes an axially sliding ?t 75 ened, the cutting edge IZI will make proper con tact at the proper angle with the cutter blade I 22. The lever I0‘I is then adjusted to raise or lower the position of the walking beams 92 and 93 so as to vary the length of the lever arms L1 and La 2,408,916 formed by the said walking beams 92 and 93 between the pivotal center of the walking beam supports 95 and st and the centers of the cross heads e?~9i at the spindle thrust bearing and 5 tion by means of the latch tongue 56 extending into the locking groove 63 formed radially in the circular rim 5'! of the stop plate. Upon depress ing the handle slide 52 radially inward against the force of the spring 55, the latch tongue 56 is cross-heads ‘l9 and 89 at the lead screw nut so that the cutter will, in effect, follow exactly the carried inwardly out of engagement with the groove 63, thus freeing the handle for rotation spiral or helix described by the cutter blade I22. of the spindle drive shaft iii. In operations where The ratio of the axial motion of the tubular spin a larger number of the same kind of tool is to be dle with respect to the axial movement of the machined or ground, it may be desirable to ad 10 lead screw nut will always be proportional to the just the angular position of the stop plate by ratio of the length of the lever arm L1 to the means of the screws 59 and E9 to provide for length of the lever arm L2. Axial motion of the identical and suitable initial settings of the ma spindle it and the chuck carried thereon is thus chine in accordance with the working require e?ected by means of the opposite axial motion ments. 15 of the lead screw nut til, acting through the two While a grinding wheel, for purposes of illus oppositely positioned walking beams 92 and 93. tration, has been shown at I20 in Figure 1, other Adjustment of the height or vertical position of the walking beam by angular adjustment of the types of cutting tools may obviously be employed to perform similar operations. arm 9'! is thus obviously effective to vary the While a preferred embodiment of the inven ratio of the motion of the spindle with respect 20 tion has been illustrated and described hereinbe to the motion of the lead screw nut between cer fore, the invention is not to be limited thereby, tain limits determined by the dimensions of the but is intended to cover any variation or modi? elements of the machine, particularly the walk cation Which falls within the scope of the claims. ing beams s2 and 93. _ I claim: Upon rotation of the spindle drive shaft l5 25 1. Apparatus for machining a helical surface by means of the handle 52, the lead screw shaft comprising chucking means for a workpiece to be 55 will also be rotated in an opposite direction machined, a coaxial shaft rotatably and axially through the action of the mutually meshing spur reciprocatably supporting said chucking means, gears t8 and ‘Hi. Accordingly, if the handle 52 a lead screw positioned parallel to and adjacent 30 is rotated clockwise, the drive shaft it‘: will like said shaft, drive means coupling said lead screw wise be rotated clockwise and the lead screw shaft 'and said shaft together for simultaneous rotation 85 will be simultaneously rotated counterclock at a fixed ratio, a nut on said screw axially mov wise at a speed which is proportional to the ratio able in response to rotation of said lead screw, a of the number of teeth on the spur gear 68 to the thrust bearing associated with and adapted to number of teeth on the spur gear '38. Rotation 35 move said chucking means axially, a walking lead screw shaft 65 and the beam pivotally coupled adjacent one end to said 7 thus imparted to the lead screw ‘56 formed thereon will simultaneously nut and adjacent the opposite end to said thrust result in axial motion of the lead screw nut 89 bearing, means to support pivotally said walking to the left as viewed in Figure 3. The motion beam for angular displacement in response to thus imparted from the nut 86! to the crossheads 40 axial motion of said nut whereby said thrust ‘i9 and 89 contained within the lower slot ID! bearing and said nut are thus coupled together of the walking beams 92 and 93 will result in through said walking beam for simultaneous ax counter-clockwise angular displacement of the ial motions. said walking beams about the centers of their 2. Apparatus for machining a helical surface supporting pins 9'5 and 93 with resultant axial 45 comprising chucking means for a workpiece to be motion of the cross-heads so and 91 to the right, machined, a coaxial shaft rotatably and axially as viewed in Figures 3 and 5. Corresponding ax reciprocatably supporting said chucking means, ial displacement of the spindle thrust bearing to a lead screw positioned parallel to and adjacent the left will result in an outward extension of the said shaft, drive means coupling said lead screw tubular spindle shaft iii. The spindle shaft will 50 and said shaft together for simultaneous rotation thus have imparted to it a simultaneous clock wise rotation and axial translation, the relation ship of one to the other of which will depend upon the beforementioned gear ratios between at a ?xed ratio, a nut on said screw axially mov able in response to rotation of said lead screw, a thrust bearing associated with and adapted to move said chucking means axially, a walking the gears iii and ‘IE1 and the ratios of the lever 55 beam pivotally coupled at one point thereon to arms L1 and L2. By computation or by experi said nut and at another point thereon to said ment, proper adjustment of the adjustment arm thrust bearing, means to support pivotally said 9? and the corresponding position of the lever walking beam for angular displacement in re it‘? may be determined for any given relationship sponse to axial motion of said nut whereby said between the angular rotation of the spindle shaft 60 thrust bearing and said nut are thus coupled to and its simultaneous axial motion. Thus any gether through said walking beam for simultane desired motion of the tool to be machined corre ous axial displacement. sponding to any desired pitch or spiral can be 3. Apparatus in accordance with claim 1 in obtained. When such relationship has been com which said pivotal walking beam support is ad 65 puted or otherwise determined, the plate I I0 may justable in position with respect to said pivotal be calibrated by the placing thereon of a corre ‘ coupling to said nut and said thrust bearing. sponding scale as shown at I09, whereby pre-ad ll. Apparatus according to claim 2 in which said justrnents of the machine may be readily made pivotal walking beam support is adjustable in po by simply setting the pointer Hi8 upon the proper 70 sition with respect to said pivotal coupling to said marking of the dial I69. As hereinbeforementioned, the lever arm 50 is normally locked in ?xed position against rota nut and said thrust bearing, _ , ANDRE CROT.