US2068915A - Drill grinding appliance - Google Patents

Description

Jan. 2 1937..

e. p. HARDIN DRILL GRINDING APPLIANCE Filed July 21, 1952 INVENTOR: Gardm D. Hardin,

ATTORNEYS Patented Jan. 26, 1937 PATENT OFFICE 2,068,915 DRILL GRINDING APPLIANCE Gordon D. Hardin, Louisville, Ky.

Application July 21, 1932, Serial No. 623,720

10 Claims.

The present invention relates to a drill grinding appliance, and more particularly to a device, associable with a grinding wheel, and operable to move a lip drill with relation to the grinding wheel in such a manner as to produce a drill point having a' much longer serviceable life tha has heretofore been considered possible.

A primary object of the invention is to provide an extremely inexpensive but highly efficient tool which may be used in small shops or on the job to grind lip drill points, and which will produce a point which is'superior in every respect to a hand ground drill point and superior in some respects to drill points ground on much more expensive machines which are now on the market. A further object of the invention is to provide a device of the character described in which all movements of the drill during grinding shall be in a straight line constituting the axis of the drill, but of such character as to produce a drill, in which relief is provided immediately in advance of the chisel edge, whereby that edge is permitted to out instead of grinding during operation of the-drill.

A further object of the invention is to provide a mechanism of the character described 1 including means for automatically advancing the drill upon rotation thereof to produce the above mentioned relief in exactly proper proportions throughout the surface of the lands of the drill. A further object of the invention is to provide, in a device of the character described, means for eifecting such advancing movement of the drill, such means being of such character as to be adjustable to accommodate the mechanism to drills of varying sizes, the adjusting mechanism being graduated so that it may be readily set to the proper position for a drill of given-size by an inexperienced operator.-

A further object of the invention is to provide a device of the character described which, after an initial careful positioning, may be readily removed from its association with the grinding wheel and thereafter readily reassociated with the grinding wheel in the proper' relation thereto.

Further objects of the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the form illustrated in the accompanying drawing, attention being called to the fact, however,

that. the drawing is illustrative only, and that change may. be made in the specific construction illustrated and described, or in the specific steps stated, so long as the scope of theappended claims is not violated.

Fig.1 is a plan view of a device constructed in accordance with the present invention showing a drill in association with the grinding wheel;

Fig. 2 is a side elevation of such mechanism, parts being broken away for clarity of illustration;

Fig. 3 is a fragmentary end elevation taken from the left of Fig. 1;

Fig. 4 is a transverse section of a detail upo an enlarged scale, and

Figs. 5 and 6 are sectional views of still other details of the novel structure.

Referring more particularly to thedrawing, it will be seen that I have illustrated a grind- 'ing wheel HI suitably mounted upon a fixed axis ll. Assuming that the grinding wheel i0 is positioned above a table or bench indicated at Si in Fig. 2, a foot piece I 2 having apertured ears I3 is positioned upon the table adjacent the grinding wheel III. Said foot piece is provided, in the illustrated embodiment, with a tongue I4 which may, or may not, be slightly flared to form a dovetail. The foot piece 12 is so oriented with respect to the wheel I!) that the adjacent longitudinal edge of the tongue I 4 is parallel with the outer flat face of the grinding wheel l0; and the foot piece is fixed in this position by lag screws, or the like, extending through the apertures of the ears II and threaded into the bench 6|. The foot piece l2, once having been positioned is intended to be permanently maintained in that position. g

A base member I5 is formed with-a. groove i6 adapted to mate with the tongue I4, and saidbase member is provided with a slot ll adapted to receive a machine screw l8 which takes through said slot l1 and threads into a suitably provided socket in the tongue M to clamp the 40 base member I! in adjusted position on the foot piece II. It will be perfectly obvious that, 7 once the foot piece l2 has been positioned properly with respect to the grinding wheel III, the base member l5 may be readily associated with said foot piece and will thereby be properly orientedwith the grinding wheel I. In small 6 shops particularly, it is highly desirable that' the base member and its associated elements shall be readily removable and replaceable in its relation to the grinding wheel HI so that. said grinding wheel may be available for other work and may not be obstructed by the drill grinding appliance. The slot l1 and clamping bolt 7 l8 permit adjustment of the base member IS with tated, the pin ends 4| and 4|" will ride over the cam face 46, thus reciprocating the spindle 36 to advance and retract the drill 40 with respect to the grinding wheel Hi. Clearly, therefore, the drill 40 must beproperly indexed with relation to the rotative position of the spindle 36 before grinding is initiated. To provide for such proper indexing, I have evolved the following arrangement. At a point on the spindle 36 which is disposed within the hub 35, I provide a radial socket 51. The hub 35 is formed with a radial bore 56, and the socket 51 is so positioned that, when the pin end 4| is in the position illustrated in Fig. 4, wherein it has just mounted the lower end 53 of the'cam face 46, the socket 51 is in registry with the bore 58. I prefer to provide a pin 59 which, in the illustrated embodiment, is an end of a tool 60 which forms a part of the equipment, andto enter said pin 59 through the bore 58 and into the socket 51, thus locking the spindle 36 in the indicated position. Thereafter, a drill 40 to be ground is entered in the chuck 39 and is rotated until one cutting lip of said drill is in an absolutely horizontal position. While a skilled operator can usually position the drill properly by measuring the position of the critical cutting lip with his eye alone, it is desirable for one who is not skilled in the use of themachine to follow the following procedure. The set screw'32 is loosened and the nut 33 is rotated until the upper end of the V rest lies inthe plane occupied by the center point of the drill 40. A straight edge is then rested upon the upper ends of the wings of v,

and the drill is rotated until one of the cutting lips thereof comes into parallelism with the lower edge of the straight edge. The chuck 39 is then tightened, care being taken to prevent movement of the drill) during such tightening.

The nut 33 is now operated to elevate the V rest 34 into a position wherein the sides of the socket lightly engage the periphery of the drill 40, whereby said rest forms a support for the drill to prevent bending thereof during the grinding operation, it being understood that the wheel ID will be rotated in a counter-clockwise direction as viewed in Fig. 3. ,The carriage 23 is now advanced to the position illustrated in Fig. 1, wherein the point of the drill projects just beyond the forward end of the rest 34, rough positioning of the carriage being effected by releasing the engagement of the member 26 with the screw 20- and final adjustment of said carriage being effected by manipulation of the hand wheel 2|.

It is to be noted that the base member l must be so adjusted upon the foot member I! that, when the drill is brought fully into contact with the flat face of the wheel ID, the spindle 36 being locked in position by the pin 58, one cutting lip of the drill will contact the grinding wheel in a line parallel to, and spaced below the horizontal diameter of said wheehthe center point of the drill being positioned very slightly beyond the peripheral edge of said flat face. The machine herein disclosed is so designed that the drill must engage the wheel at a point below the horizontal diameter, the optimum point being dependent upon the diameter of the wheel. However, in a machine having the range of the embodiment illustrated herein, an arrangement such that the cutting lip engages wheels from 6 to 12 inches diameter in a line spaced one inch below the horizontal diameter thereof will give satisfactory results in grinding drills within the capacity of the machine. While this compromise position is generally satisfactory, extreme nicety may be attained by lining up the machine in such a way as to cause the drill point to engage the face of the wheel at a point spaced forty-five degrees from the horizontal diameter of the wheel; and this recommended adjustment is independent of the diameter of the wheel.

The parts having been set up in the manner above described, the pin 59 is removed from the socket 51 and the bore 58 and the spindle 36 is turned in a counter-clockwise direction as viewed in Fig. 6, whereby the pin end 4| is backed off of the cam face 46. The spring 38 thereupon, of course, retracts the spindle 36 so that a slight clearance is left between the drill end and the grinding wheel 18. Rotation of the wheel I0 is now initiated and,'when the wheel has obtained its normal speed, the operator grasps the hand wheel 31 and turns the spindle 36 in a clockwise direction as viewed in Fig. 6. As the spindle is turned, the pin end 4| again rides up on the end 53 of the cam face 46, thus moving the drill into contact with the face of the wheel 10. Further rotative movement of the spindle 36 causes further advancement of said spindle and the drill, whereby the center point of the drill is caused to project farther beyond the peripheral edge of the wheel iii, and whereby the followingportion of the drill land is brought into contact with the grinding wheel. The cam face 46 is so designed that it automatically effects a sufficient advancement of the drill 40 to grind the drill land in such a manner as to give an optimum relief to said land and to provide an increasing relief adjacent the chisel point of the drill. The pin end 4| drops off of the end 54 of the cam face 46 just as the rear edge of the drill land leaves its contact with the wheel face, whereby the spring 38 is permitted to retract the drill 40, again providing a clearance between said drill and the wheel, and preventing grinding off of a portion of the chisel edge of the drill. The pin end 4| rides up onto the end 53 of the cam face'46 just in time to bring the second lip of the drill properly into contact with the wheel I0.

I prefer to recommend to unskilled operators that they turn the spindle through two complete revolutions before moving the carriage 23 from its initial position of adjustment in order to be certain that both lips have been given a sufficient length of time in contact with the grinding wheel. Skilled operators, however, can obtain substantially perfect results by giving the spindle only one revolution between advancement of the carriage.

After both lips of the drill have been satisfactorily ground from the initial position of the carriage, the spindle 36 is left in a position wherein the pin end 4| is just ready to mount the end 53 of the cam face 46, and the hand wheel 21 is manipulated to advance the carriage slightly. Thereafter, the spindle 36 is again rotated, and this procedure is continued until a satisfactory point has been provided for the drill.

It will be obvious that the device of the present application is extremely simple and inexpensive to manufacture; that it has few delicate parts which will be subject to damage or breakage, so that it can be handled comparatively roughly with safety; and that it is capable of operation by a decidedly unskilled worker to produce excellent drill points. It is also obvi- In onsaidwheeLaIootmunberiimdiymsiiimcdwlihrupccttoslldwhocl,

mchtcdwithsaki!ootmunbs,almmaline mandlneansior idm. holdingmeansmbothdireetimswithrewect videdwithacylindricalhlihadrillholder mounted in said hub for reciprocatim and rotationwithrespect thereto,andcammeamfor eilfecting reciprocation of said holder upon rotation thereof, said hub and holder being provided, respectively, with a bore and a socket, and said bore and socket being of corresponding diameters and being alignedwitheachotber in one relative'position only of said hub and bolder.

4. InadeviceofthecharacterdescribeiLaba-se. a drill holder mounted on said base for reciprocation and rotation with respect thereto, resilient means tending to retract said holder, a plurality of radially oppositely projecting fingers carried by said holder, a cam block mounted upon said base and disposed in the path of movement 01 said fingers, said block being oscillahle about an axis disposed substantially in the plane of initial contact of said fingers with said cam block, and means for eiiecting predetermined variations in' the position of said block, said fingers and block cooperating, at times, to advance said holder against the tendency of said spring.

5. Ina drill grinding appliance, a member having a substantially horizontal bore, a spindle reciprocably and freely rotatably mounted in said bore, a chuck carried at one end of said spindle for receiving a drill, two fingers fixedly associated wlthsaidqhdleand loiccflngmtelyfliere- Irmflnamot-flmbeingndialwith mmectto-iddrflihdda,aeammountedad a'- cultlids indbandpodtloncdinthepathd slidmmnsaaodatedwithsaids indle andrmmthelmeinadirectimto lxfldsfldilngersauintthetaoednidcam. mflrnlyilztheefloctmdddmckd theeoqlanfllndaidcamandm .Inadflllgflmlingamihnoaamunberlnvimaallhnfioliyhminmtalboreas indleremandfieelymtaiahlymolmtedinaid madm'ckcaniedatmemdotsudqindle 'tm'mcdvingamtwofingunfimdlyaslodaind wiihnldslinllleandmoiecfingn h lymsitelyflndzmanelunmtpvoialiy' earned an nia-mhuammthem mmnnsopaalietomonemddsaid ehnmtiowardmiddmiandmansaaodatul withnidqindleandmsilimflymgingthesam mamlnaaaunnoas saiiehnmt.

' 7.Inadrillappliance,amunbuhaving a adsiantially hmimntal bore, a qnndle Mandfledymhtahlymountedinslfl madnltmn-bdatomuniotsaidsnndle' mmavmammmnnmsfimdly nitdytherefrmanehnmt ivotallymmedon saidmunberandposiiimedinthepathdsaid mmeansoperalfletoswmgoneenddsaid elemmt toward said chuck, said last-named meansbmngtoindicatethedegmeof stantially horizontal bore, a spindle reciprocable and freely rotatable in said bore, a chuck carried at one end of said spindle adjacent said wheel for receivingadrilLaspringassociatedwithsaid spindle and urging the same away from said wheel, means limiting movement of said spindle under the influence of said spring, two fingers fixedly associated with said spindle and projecting radially oppositely therefrom, a cam element pivoted at one end adjacent said spindle and positioned in the path of said fingers, and means for Swinging the free end of said element toward said wheel.

10. In a drill grinding appliance for association withagrindingwheeLamemberhavingasub-IG ing radially oppositely therefrom, a cam element pivoted at one end adjacent said spindle and positioned in the path of said fingers, and means for swinging the free end of said element toward said wheel, said last-named means being graduated to indicate the degree of movement thereby of said element.

GORDON D. HARDIN.

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