US2580884A - Drill sharpening apparatus - Google Patents

Description

A. H. BOWMAN DRILL SHARPENING APPARATUS Jan. 1,71952 3 Sheets-Sheet l Filed May 25, 1949 Inventor mit.

A/t'uarlv H. Bowman Jan 1, 1952 A. H. BOWMAN 2,580,884

' I DRILL SHARPENING APPARATUS Filed May 25, 1949 s sheets-sheet 2 A" '//////////////,m 66 l! /26 60 54 62 H l Albert H. Bowman Jan. 1, 1952 A, H, BOWMAN 2,580,884

DRILL SHARPENING APPARATUS Filed May 25, 1949 3 Sheets-Sheet 5 Inventor Albert H..B0wman v u By WW Patented Jan. 1, 1952 UNITED STATES PATENT oFFIcE DRILL SHARPENING APPARATUS Albert H. Bowman, Los Angeles, Calif. Application May 25, 1949, Serial No. 95,210

I I I (C1. 51-21s) 8 Claims.

This invention relates to new and useful improvements and structural refinements in drill sharpening apparatus, and the principal object of the invention is to provide an apparatus of the character herein described which embodies in its construction a drill holder adapted1 for swinging or rotation on an axis guided by mechanical means so as to assure accurate formation of desired lip angle and lip clearance on the drill being sharpened,

An important feature of the invention, therefore, resides in the structural arrangement of the guiding means for the drill holder, andv another' feature of the invention involves the provision of means whereby the apparatus may be adjusted to form lip angles and lip clearances of different angular magnitudes, as well as to form a constant or a varying lip clearance from the periphery to the axis of the drill.

A still further feature of the invention resides in its adjustability to accommodate drills of various diameters and in its additional adjustability for the formation of different lip clearances.

An. additional feature of the invention resides in the provision of gauge means for pre-setting a drill in position in the apparatus, so as to assure that the sharpening operation may be properly7 and correctly performed.

VSome of the advantages of the invention reside mits simplicity of construction, in its adaptability for use in association with grinding wheels of different types, and in its adaptability tor economical manufacture.

With the above more important objects and features in view and such other objects and features as may become apparent as this specification proceeds, the invention consists essentially in the construction and arrangement of parts as shown in the accompanying drawing in which:

Figure 1 is a top plan view of the invention showing a drill in place therein; l

Figure 2 is a top plan view, similar to that shown in Figure 1, but illustrating the invention in a relatively dierent angular position;

Figure 3 is a side elevational view of the invention as shown in Figure l;

Figure 4 is a perspective View of a supporting member used in the invention; K

Figure 5 is a perspective view of a carrier used therein;

Figure 6 is a cross-sectional view, taken substantially in the plane of the line 6-6 in Figure l Figure 7 is a cross-sectional view, taken substantially in the plane of the line 1-1 in Figure 6;

Figure 8 is a cross-sectional view, taken substantially in the plane of the line 8-8 in Figure 3;-

Figure 9 is a cross-sectional view, taken substantially in the plane of the line 9-9 in Figure 3;

Figure 10 is a fragmentary plan View showing the gauge means used in installing the invention; and

Figure 1l is a fragmentary front elevational View of the device with the drill holder in a lowered inoperative position and with the lipaligning gauge contacting the lip of the drill.

Like characters ofA reference are employed to designate like parts in the specification and throughout the several views.

Referring now-to the accompanying drawings in detail, the invention consists of a drill sharpening apparatus designatedgenerally by the reference character 20, the same including a rotatable grinding disk or whel 22 having a at face 24 with'which the drills are engageable for grinding or sharpening purposes.

Broadly, the invention resides in the provision of means for holding a drill in a proper predetermined position relative to the face 24 of the grinding Wheel so that the sharpening operation is eected while maintaining proper lip angle of the drill and controlling the lip clearance.

The means referred to in the preceding paragraph consist of a suitable stand 26 which is adapted to be secured by the bolts 23, or the like, to a supporting surface 30, such as for example, the frame of the grinder. `A base member 32, preferably assuming the form of a strap, is formed with a slot 34 to receive a bolt 36 whereby the member 32 is adjustably secured to the element 26the base member 32 being also provided with an additional slot (not shown) to receive a further bolt 33. The bolt 38 extends through a slot 4i? provided in a supporting member 42 and a suitable adjusting screw 44 extends through a screw-threaded aperture 46 into the slot 4U and is engageable with the bolt 38 for the purpose of releasably locking the latter.

The supporting member 42 is substantially horizontal and is provided with a vertical extension 48, the purpose of which will be hereinafter described. The member 42 is also formed integrally with a tubular portion 50, the bore of which provides a bearing for a pivot pin 52. The latteris formed intermediate the ends thereof with a frusto-conical shoulder 54 which engages a countersink 56 provided in the bore of the bearing 50, the shoulder 54 abutting an arm 58 towhich the pin 52 is rigidly secured by means of a nut 60. Needless to say, the pin 52 is freely rotatable in the bearing o and is provided with a retaining nut 62 locked by a screw and washer 64, `86, respectively (see Fig. 8) whereby the pin 52 is prevented from being withdrawn from the bearing 50.

The arm 58 is provided with a lateral extension 68 which, in turn, is formed with a horizontal bore, the axis of the latter being illustrated at 18. The bore of the extension 68 of the arm y58 accommodatesa further pivot pin 12 which is similar in construction to the aforementioned pin 52 and is rigidly secured to a cam-shaped portion 14 of an L-shaped carrier 16 by means of a screw 18 extending through an aperture 80 with which the cam portion 14 is formed. A nut, washer and lock screw assembly 82' is provided on one end portion of the pivot pin 12' for the" purpose of rotatably retaining the pivot p in in the extension 6B, the assembly 82 being similar to the aforementioned elements 62, 64, 66.

The axis of the pivot pin 12 is also represented by the aforementioned axial line 10, and it will be noted that while the cam portion 14 of the carrier 16 is vertical, the remaining portion of the carrier is horizontal and is formed with an aperture 84 to receive a screw 88 whereby a drill holder assembly 88 is mounted on the carrier'. The holder assembly 88 includes in its construction a base portion 00 which is secured to the carrier by the screw 88, whilev a drill cradle S2 is slidable longitudinally on the base portion 90, this being effected by providing the cradle and the base portion with coacting dovetail guides 04. Mechanical means are employed for sliding the cradle 92 on the baseportion 80, these means consisting of a screw 96 rotatable in a screw# threaded lug 88 which is formed integrally with the base portion 80, the screw 86 rotatably engaging an eye |00 which is screw-threaded asat |02 into the cradle 02 andl is movable in a slot |04 with which the base portion 90 is provided, as shown in Figure 'l'.

One side of the cradle 492 is formed withA a; V-` shaped channel |06 to receive a drill |08, this drill being retained in the channel |06 by a laterally shiftable block H0 provided in the cradle S2. This block is actuated by means of a rotatable adjusting screw ||'2 and it will be observed that the block I0' is also equipped with a guiding pin H13 which slidably extends through one side portion of the cradle 92.

A stud ||6 projects outwardly from one end of the cradle 92 and a clamp ||8 is slidable on this stud, being adiustably secured in position thereon by a set screw |20. A shaft |22, disposed in parallelism to stud ||6, is slidable through the clamp |i8 and is adjustably and reversibly se;

cured therein by an additional set screw |24. A

plate or tab |28 is rigidly secured to one end or the shaft |22 and is adapted to abut the drill |88 in the manner shown, so that the position of the drill in the holder 88 may be preadjusted by setting the clamp I8, as will be clearly apparent. Itis to be noted that the position of the shaft |22 in the clamp ||8 may be reversed when it is not necessary to extend the shaft to accommodateextra long drills.

A drill pre-setting gauge |28 is also provided, this gauge simply assuming the form of an arm which is swingably mounted on a bolt |30, the latter extending through a screw-threaded aperture 232 formed in the aforementioned extension 48 of the 'supporting member 42. The arm |28 is provided at its outer end with an angu-lated 4 portion |34 which may be aligned with the lips |36 of the drill |08 when the arm |28 is swung toward the holder 88.

The aforementioned bolt |30 also carries a rotatable cam |38, a graduated indicator disk |40 and a lock nut unit I 42, the latter including a nut of the stop nut variety, so that it does not need to be tightened against the gauge |28, but permits pivotal movement of the gauge on the bolt |30 independently of the cam |38 and disk |40. Moreover, the indicator disk |48 is conveXo-concave and is formed from resilient material, so that it frictionally engages the cam |38 and discourages rotation of the latter on the bolt |30. A spacer sleeve |44 is provided between the disk |40" and the' adjacent surface of the extension 48, so as Yto prevent the disk from collapsing and losing its resiliency.

It may be explained at this point that the aforementioned holder 88 is adjustable on the carrier 16: inthe direction of the arrow |416, this being effected by simply loosening the screw 86. The relative position of the holder on the carrier is indicated b'y a pointer |48 formed integrally with the base` portion 880ithe holder, theA position lof. they pointer |l48` being determined by means of a graduatedN scale |50 with which the carrier 16 is provided, asV is' best shown in' Figure 5=.-

It willbe' also' observed from the-foregoing that the holder 88 together with the carrier' 18 are swingable about a horizontal axis,- namely, the axis 10 of the pivot pin.12, this swinging move-l ment being indicated at |52. in' Figure .A Moreover, it is to' be noted that the holder 88 and the carrier 16 are rockable together with theY arm 58 on the pivot pin 52, as indicated at |54 in Figure 3, during which action the cam surface portion 14 of the carrier may engage the cam |38, as shown. However, the arm 58 together with the carrier and drill holder may be swung to a non-operative position illustrated by the phantom lines |56l in Figure 3, in which` position they are supported by anarcuate stop member or strap |58 which is bolted to the arm 58 as at |60 and is provided with an angulated end portion |62 which is engageable with the under sur.- face of the supporting member 42 when the holder is swungto the inoperative position, as shown.

It will be noted that cam- |38 has an index mark or poi-nter |66, and the graduated disk |40 has two scales |68 and |10. The scale |68 is used when the axis 10 is set parallel with the face of the grinding wheel as shown in Fig. l, and scale |710 has its graduations spaced further apart than those of the scale |68y to adapt it for use when the axis 10 is set at an angle to the face of the grinding wheel as shown in Fig. 2. By loosening bolt |30, the disk Y|l|0may be turned to position the desired one of said scales at the left of bolt |30, as viewed in Fig. 3, for coaction with the index mark or pointer |66.

Tov aid in installing the present device upon a grinding machine, a gauge |64 is used as shown in Fig. 10. By clamping the gauge |64 inthe drill holder 88, the operator may employ it to align and locate the device at a fixed distance relative to the abrasive surface 24, whereupon the bolts 36 and 38 are tightened. Fig. 10 shows the proper positions of the various elements when installing the device'. In order words, cams |38 and 14 are engaged, holder 88 is horizontally disposed, and gauge |64 is secured in holder 88 and engaged with the abrasive surface 24'. At this time, cam index |66 is set at zero on disk |48, and cradle 92 and base 90 are ush at their for-r ward ends, thus establishing ah iixed distance from the surface 24 to the axis 10.

In use, the diameter of the drill to be sharpened is noted, and the index |66 on cam |38 is rotated relative to disk |40 to the graduation of the latter designating such diameter. The drill is now inserted in holder 88 While the latter is positioned in the dotted line position |56 of Fig. 3, thumb screw I2 is tightened to hold the drill, and shank stop |26 is adjusted to abut the drill shank. The drill is thentemporarily released by loosening screw ||2, whereupon the drill is rotated for alignment under gauge |28, and screw ||2 is again tightened.. The holder 88, carrier 16 and arm 58 are then swung upwardly about pivot pin 52 so that cam 'I4V is engaged with cam |38, whereupon the drill is advanced to the abrasive wheel v22 by the feed .screw 96. The holder 88 is then oscillated as at |52 about pivot pin 'i2 while maintaining cam i4 in engagement with cam |38 so that proper lip clearance is imparted to the drill. The magnitude of this lip relief is proportional to the magnitude of its particular eccentric position and the radius of the oscillating motion imparted to the lip.

After the lip |36 of the drill |08 is sharpened in this manner, the screw ||2 of the holder 88 may be loosened and the drill may be rotated so that the remaining lip or lips thereof may be sharpened in a like manner, this being repeated u in instances of multi-lip drills until all the lips are sharpened to a uniform angle and clearance.

Cam |38, having a convolute form and being pre-set to a graduated scale on disk |40, acts as a regulator to equalize the radius of the oscillating motion imparted to the drill lip to conform with the variable eccentric caused by drill core thickness dierences, thereby assuring an approximate sameness of lip clearance on all drills within the capacity of the device by proper setting of cam |38 to coincide with the diameter of the drill. However, the cam |38 may be set at a greater or lesser reading than the drill diameter to form a lip clearance of different predetermined magnitude without readjustment of screws or bolts.

It is to be observed that when the set-up shown in Figure l is used, the axis is parallel to the face 24 of the wheel 22, and accordingly, a true conical grinding action is achieved, which results in the formation of a lip clearance of constant magnitude from the periphery to the center of the drill. However, if it is desired to gradually increase the lip clearance from the periphery to the center, the bolts 36, 38 may be adjusted so that the axis l0 of the pivot pin l2 is disposed, for example, at a ten degree angular deviation from the face 24 of the wheel 22, as

shown in Figure 2, while the holder 88 is adjusted on the carrier 16 so that the pointer |48 is in alignment with the 49 degree mark of the scale |50. In this manner, the lip angle of the drill still remains at 59, but the angular deviation of the axis l0 from the face 24 of the wheel 22 offsets the conical grinding action from the axis of the drill so that the lip clearance is progressively increased from the periphery to the center.

Needless to say, while in the foregoing description the lip angle of the drill was referred to as equalling 59 in accordance with conventional practice, the adjustment facilitated by the screws 36, 38, 86 may be varied so as to accommodate lip angles of other magnitude, as will be clearly apparent.

It is believed that the advantages and use of the invention will be clearly understood from the foregoing' disclosure, and accordingly, further dei scriptionthereof at this point is deemed unnecessary.

Having described the claimed as new is:

f l. In .a drill sharpening apparatus including a grinding wheel, the combination of a base member extending horizontally and pivotally secured to af stand, a supporting member which is substantially horizontal and is provided with a longitudinally extending slot in one end, the opposite end terminating in an integral tubular bore, a rockable arm connected to said supporting member and provided with a pivot having its axis disposed at a predetermined angle relative invention, f .what is to the axis of said grinding wheel, a swingablecarrier mounted on said pivot, a holder mounted on said carrier land adapted to support a drill with a lip of the latter in engagement with a radial face of the grinding wheel, and means comprising a cam engaging surface responsive to the swinging of said carrier for guiding the rocking movement of said arm so Ias to vary the position of said holder relative to said grinding wheel and thereby control the lip clearance of the drill being sharpened.

2. The device as defined in claim 1, together with means for adjusting the angle of the axis of said pivot relative to the axis of said grinding wheel, said holder being adjustable relative to the carrier and means for adjusting said holder relative to said carrier.

3. The device as dened in claim 1 wherein said means includes a cam provided on said carrier, and a rotatably adjustable cam rest on said supporting member engageable by said cam.

4. The device as dened in claim l, wherein said means include a rst cam xed on said carrier, and a second rotatable cam adjustably mounted on said supporting member and providing a rest for the rst cam, said carrier comprising an L-shaped member, and said rst cam being integral therewith.

5. In a drill support for a drill sharpening machine including a grinding Wheel, the combination of a base member adapted for attachment to the frame of the machine, a supporting member adjustably mounted on said base member, a rockable arm connected to said supporting member and provided with a pivot having its axis disposed at a predetermined angle relative to the axis of said grinding wheel; a swingable carrier mounted on said pivot and provided with a cam, a holder comprising a base portion adjustably mounted on said carrier, a drill cradle slidable longitudinally on said base portion, and adapted to support a drill with a lip of the latter in engagement with ya radial face of the grinding wheel, means for adjusting the position of said holder on said carrier and a second rotatable cam adjustably mounted on said supporting member and adapted to be engaged by the first-mentioned cam whereby the rocking movement of said arm and the swinging movement of said `carrier may be guided to vary the position of said holder relative to said wheel and to control the lip clearance of the drill being sharpened.

6. The device as defined in claim 5, wherein said holder includes a base portion adjustably attached to said carrier, a drill cradle slidable on said base portion toward and away from said wheel, and a pointer and cooperating graduated scale means for indicating the relative position of the holder on the carrier.

"L The device as defined, in claim 5,. together with a vertically swingable. drill. presettinggauge mounted. on said supporting member and having a horizontal lateral arm engageable with a. lip of a drill in said. holder when the latter and the carrier are swung away from the grinding wheel.

8. In a, drill sharpeningk machine, the combination with. a base and integral arm means thereon, of an' adjustable strap member horizontally disposed thereon and; pivotally secured to said base, a supporting member pivoted to said strap member and` extending horizontallyr Said supporting member comprising an integral tubular bore. at one end for receiving a pivot pin, an arm'swingably fastened by said pivot pin, said arm terminating in a second pivot pin, an L.shaped carrier pivotally secured to said arm by said second pivot. pin, a drill holder mounted on said carrier, said holder having a base portionwhich is secured to said carrier, a drill cradle slidably secured on said base portion, a cam surface integral 'with said L-shaped carrier member, a second cam member secured to said supporting member and cooperating with said rst. mentioned caml surface, and means ccmprising a graduated scale and, disk for setting the. second cam` member relative to the first cam surface to control the lip clearance of the drill being sharpened.

ALBERT H. BOWMAN.

REFERENCES CITED The following references are of record inl the file of this patent:

UNITED STATES PATENTS Number. Name Date 183,798 Champlin Oct. 31., 1876 411,845 Walker Oct. 1,. 1889 523,897 Kenyon July 31, 1894 613,127 Eames Oct. 25, 1898 707,549 Chandlerl Aug.. 26, 1902 864,546 Lange Aug. 27, 1907 1,524,672 Rabut Feb. 3, 1925 1,994,975 Williams Mar. 19, 1935 2,142,923 Stocking Jan. 3, 1939 2,356,175 Olsonv etal. Aug. 22, 1944

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