US1873612A - Grinding device - Google Patents

Description

A. A. MARTELL v GRINDING DEVI CE Filed Dec. 51, 1951 2 Sheets-Sheet 1 IN VEN TOR.

M 1T m m M v a 0 J wdwx TORNEYS.

Aug. 23, 1932. A. A. MARTELL 1,373;612

GRINDING DEVICE F ild Dec. 51, 1931 2 Sheets-Sheet 2 INVENTOR.

BY [M Mid/x M TTORNEYS.

:UNITED STATES PAT ALBERTA. MARTELL, OF WOONSOCKET', RHODE ISLAND,

substantially then adjusted to present a the use of the bit, and, therefore,

Patented Aug. 23, 1932 ENT "omee nssrelvon r0 MARTELL ii /mun;

racrunme COMPANY, or woou'socxnr, nnonn ISLAND, A conronnmron or mops ISLAND Application filed December 31, 1931. Seria1No.:584,154.

The present invention relates broadly to grinding devices and more especially'to a grinding apparatus adapted for grinding detachable bits fordrilling rock.

Rock drill bits comprise short detachable members adapted to be mounted on the working end of a rock drill and after the bit is dulled to the limit of its useful life,'it isthe present custom to abandon the point and replace it by a new one. The present invention contemplates reclaiming these aban doned points by providing a simple holder for a bit which will automatically correctly present the drill faces to a grinding whereby the cutting edges of the drill bit may be restored to a useful condition. Drill bits are made in various sizes and the drill heads are standardized relative to the size of the shank or thread portion of the bit."

For example, one-inch threaded bits are pro vided with drill heads of the sizes which differ by eighth inch intervals between the sizes two and one quarter inches to one and five eighths inches. Other larger or smaller shanks carry proportionally ranged head It is the purpose of the present invenmeans whereby the larger sizes. tion to, provide standard sizes may be ground into the'neXt smaller standard size and thereby, provide doned or discarded drill bits.

the drill bit is locked fixed position in a holder.

in a predetermined This holder is ,adapted to cooperatein definite fixed relatlon with a tool rest which may be moved toward the face of a grinding wheel at such position and angle as to properly grind one set of faces on a drill bit. The tool rest is 7 new supporting face for the tool holder so that the remaining sides of the drill bit may be ground to provide suitable cutting edges. The ends of the cutting faces are usually worn away during a third tool wheel vention.

increased utility for aban operations' GRINDING DEVICE holding face provided-which properly po sitions the side ofthe bit for over-all dimension of the bit to v bringing the outer corners of the faces to the proper sharp formation. In order to faciliing operations, the tool rest is tate the grind 7 adapted to be brought against an adjustable grinding the stop so that the amount of grinding taking place at each operation. is definitely controlled whereby relatively unskilled labor may be utilized for the grindingoperations."

It is recognized that the present inventions may be embodied in constructions other than those specifically disclosed herewith and, therefore, the present disclosure is-to be understood iting sense. 7

Fig. lis a front elevational view of a grinding wheel with the tool rest mounted in front of the wheel to properly addressa drill bit to the face of the wheel.

Fig. 2 is a side elevational view of the construction shown in Fig. 3 is ground in Fig. 1. I 1 a plan view of the face of a bit accordance with the present insize, thereby} as illustrative and not in the lim- Fig. 4 is anelevational view of the bit shown in Fig. 3. y r

5 is an end view of a bit tool holder.

' Fig. 6 is aside view of'the device shown in V Fig. 5. J

Fig. 7 is a plan view of ajig'for setting tool holder prior to the grinding Fig. 8 is a front shown in'Fig. 7.

Fig. 9 is a cross-section on line 99 of Fig. 2. Referring to the drawings and more especiallytoFigs. 1 and 2, a grinding wheell elevational View of the jig is mounted upon a spindle 2 which connects with for rotating grinding wheels. the frame 4 of the grinder may be provided with a. bracket 5 on which'a supporting arm driving mechanism common in the art A portion of sides. ofthe shaft ,.-f the opening 11.

6 issecured by stub bolts 7. This supporting arm 6 carries a supporting shaft 8 which preferably is provided with a shoulder 9 and annut 10 carried by the outer end of the sup-' porting shaft 8 is adapted to clamp the shaft tightly in position in the supporting arm 6.

This supporting'shaftS is provided in the forward portion'with'an opening 11 extending axially of the shaft and a pair of slots 12 arecu'tlthrough diametrically opposite 8 adjacent the inner end A slide rod 14 is mounted for reciprocating movement in the opening 11 and carriesacrosspin 15 which passes 1 8. The rotatable sleeve 17 may be-provided served that through "the, slots 12 and throughdi'ametri cal" opposite sides of astop collar 16 so that when the slide rod 14 is moved endwise in the opening 11, the stop collar is correspondingly slid along the'supporting shaft 8. The for wardend of the slide rod 14'is screw threaded and engages the screw threads in a rotatable sleeve 17 whichcarries a. knurled head with an annular groove19 into which the end-of a guidescrew'2O extends so that the rotatable sleeve is .lockedfor rotation in the end ,of the supporting shaft 8. A work rest 21 isslidably and normally rotatively mount ed on the outer. end of thesupporting shaft 8. This work rest is providedwith two pairs of supporting faces 22, 24' and 25, 26. Pref- 27. and 28 are arranged on the supporting faces 22 and 25 adjacent the I erably, stop spins side nextto the grinding wheell. Theplan es 7 of each pair of these supporting faces 22, 24,

and 25, 26 meet at substantially right-angles to receive a substantially square cross-sectiontool'holde'r. The planes of the faces 22, 24

meet in a line that is inclined upwardly relatively to the face of the grinding wheell and inwardly towardthe axis of this grinding wheel. The planes of the faces 25,26 meetin a line that is inclineddownwardly relative to the face of thegrinding wheelland "also inwardlytoward the axis thereof. The

work slide 21 is provided with four keyways 29; 30, 31, and 32, which areadapted to cooperate with a short key 34 fixedly mounted in the supporting shaft 8. It will be obby moving the work slide 21 toward the knurled head 18, a sufli'cient distance to clear the short key 34, that the work slide maybe rotated on the supporting shaft 8 to bring any one of the-four keyways into coop eration with the short'key 34. supporting faces 35, 36 meeting at right angles, are provided on the side of the work slide 21 and it will be noted that the sup porting face 36 comprises a'plane which is an- .gularly disposed to the face of the grinding ,wheel. 1. v

The keyways 29, 30, 31, and '32 areslightly wider than the shortkey 34 so that the work rest may be given a limited rotative oscillatory movement when the grinding is bepositions supporting faces 22, 24; for

A pair. of

wardly on the shaft 8 over ing done to smooth the work, toprevent uni-due local wear on the wheel, and also to prevent burning the work. When the respective keyways engage the short key 34, the following work faces are positioned in operative relation to the grinding wheel; keyway 29 grinding one set of faces of the drill bit cutting edges keyway positions faces 35 and 36 to grind the ends of the cutting edges; keyway- 31 positions the faces 25, 26jto' grind the other set of faces 'of'the cutting' edges;

and'keyway 31 holds the work rest in neutral position to permit the use of a. grinding wheel a longitudinal opening 39 coaxial with the axis of the tool holder. The shank off the drill bit 37 is adapted to fit the opening 39 and to be clamped there-in means of set screws 40.

Figs. and 8 illustrate jig for correctly the drill bit 37 in the tool holder positioning 38. Tl1lSj1g comprises a base 41 having a crossed opening 42 provided therein. A web 44. extends from one edge of the base in a vertical direction and a guide head extends 1 fromthe web 44 substantially parallel to the base 41. The guide head 45 is provided with 1 an opening 46 which is substantially equal to the cross-sectional dimensionof the tool holder 38.

In the operation of the device, a drill bit 37 is set on the base 41 of the jig with the cutting edges of the bit setting in the crossed opening 42 of the jig. The tool holder 38 is slipped into the opening 46- of the jig and over the shank of the drill bit 37 in the jig. The set screws 40 are tightened andthe drill bit is now locked in the tool holder-with the cutting edges of the bit definitely positioned relative to the sides ofthe tool holder- The tool holder is now placed against the supporting, faces 22, 24 on the work rest 21 with the forward end of the tool holder'in contact with the stop pin 27, which prevents the drill bitfrom being drawn into the face of the grind The work rest is now slid foring wheel.

7 the key 34 toward the face of-the rotating grinding wheel 1 land the wheel operates to grind one face of the bit on the angle indicated bythe planeA of Fig. 4. When the bit is dulled, before the rinding operation, the" cutting edges are ivorn :down to be substantially fiat tops and the first grindingoperation is continued until the grinding wheel cuts away the metal to substantially the middle part of the dulled flattened edge. When this point in grinding has been reached, the knurled head 18 is rotated to bring the stop collar 16 against the front end of the Work rest, thereby limiting the forward movement of the work rest toward the grinding wheel. Thetool holder 38 is then turned through 90- with the front end thereof against stoppin 27 and the work rest is moved toward the grinding Wheel until stopped by the'stop collar 16, thus grinding a second face on the drill bit. After the cutting edges have all been ground on one face or side, then the work r'est21 is moved outwardlytoward the knurlednut 18 to clear faces, 35, 36 and with the key 34' and the work rest is turned through 180 and then moved inwardly so that the key 34 now engages the-keyway 31,

thereby bringing the supporting faces 25, 26 into operation. The tool holder as now positioned on the supporting faces '25, 26, is

brought in contact with the stop pin 29 which prevents the work from sliding into the wheel, and the work holder is moved toward the rotating grinding wheel until the work holder is stopped by the collar 16. The work holder is again turned through and the grinding operation is continued to grind the faces indicated by the plane B of Fig. 4.

Even after the fiat tops or edges of the bit have been brought to a sharp edge, the outer are usually defaced so that it becomes desirable to grind the bit on the ends of'the edges dimension C shown in Fig. 3. A proper adjustment for the stop collar 16 is made. The work rest is turned through 90 so that the short key 34 engages the keyway 30, thereby bringing the supporting faces 35 and 36 on top of the work rest. The tool holder 38 is brought into contact with the supporting the end of the tool holder against the stop pin 47. The workrest 21 is now moved toward the face of the rotating grinding wheel 1 and the ends of the cutting faces on the drill bit 37 are ground away until the work rest 21 is stopped by the stop collar 16. This reduces the diameter of the bit to the proper dimension.

It will be observed that the supporting face 36 is angularly disposed to the face of the grinding'whe'el 1 so that the ends of the cutting edges of the bit 37 are properly undercut during the grinding operation.

From the foregoing, it will beobserved that the present invention provides a rigid, at

comprising a plurality of pairs of supportwork face of the I with a grinding wheel, guiding means, a

ing'surfaces inclined relative to the face. of thegrinding wheel, one of said pair of surfaces being inclined in one direction toward the face of'said wheel and the otherof said pair of surfaces being inclined in the opposite direction toward the face of said heel, and

a work holder cooperative with said work rest to wheel.

2. Agrinding present'a drill bit to saidgrinding device f or drill bits a as;

ing a grinding wheel, guidingmeans, a work rest mounted for reciprocatory movement on said guiding means, an

grinding wheel, said work wheel, one of said pair of c lined in one direction toward'the face of said wheel and the other of said pair of surfaces adjustable stop" to limit the movement of said rest toward the rest comprising a e plurality of pairs ofsupporting surfaces inclined relative to the face of the grinding surfacesbeing inbeing inclined in the opposite direction toward the face of said sent a drill bit to said 3. A drillbit ing wheel, guiding means, a work rest slidgrinding wheel.

ably and rotatively mounted on said guiding rest having a plurality of; supporting surfaces, a bit holder adapted to cooperate'with the supporting surfaces on 9 means, said work said work rest to present a drill bit to the workface of the grinding wheel, said bit holder 'comprisinga separate block "unattached relative to the work rest, and a stop said work rest to to limit the movement of Wards said grinding Wheel.

4. A drill bit ing wheel, guiding means comprising a shaft,

a work rest slidably and rotatively mounted a on said guiding means, said work resthaving a plurality of pairs of angularly disposed supporting surfaces, a bit holder adapted to cooperate with the supporting said workrest to present a drill bitfto the grinding'wheel, a stop to limit the movement of the tool holder on said wheel, and a' Work holder cooperative with said work rest to'pre grinder comprising a grind grinder comprising a grinds'urfaces on surfaces, and an adjustable stop to'limit the movement of said work rest towards said grinding wheel.

5. A drill bit grinder comprising a grind ing wheel, guiding means, a work rest slid- I ably and rotatively mounted on said guiding means, a'plurallty' of supporting surfaces on sald work rest,'means to retain said work rest In a predetermined rotatlve posltlon on said guiding means to render a predetermined supporting surface efi'ectlve relatlve to said grinding wheel, a tool holder adapted tohold the drill bit to be ground and to cooperate the supporting face'on the work rest to present cutting edges on the drill bit to the grinding wheel for grinding, and an adjustable stop to limit the movement of said 7 work rest toward the grinding wheel. I 6. A drill bit grinder comprising a grindmeans to render'a predetermined pair .the supporting face on sent cutting edges on the drill bit to the grindthrough saidshaftfto adjust said stop. a

ing wheel,

s r on said gulding means, said work rest com-' inclined upwardly and inwardly the drill bit to ing wheel forgrinding, an adjustable stop to limit the movement'of said work rest toward the grinding wheel, and; means extending 7. A'd'rill'bit grinder comprisinga grindgrinding wheel, a work rest slidably mounted prising a plurality of supporting surfaces angularly disposed to the plane of the face of the grinding wheel, said supporting'surfaces being arranged iii-pairs with onejpair of supporting surfaces meeting at a line which is relative to the plane of rotation of the face of the grinding wheel, and another pair of wardly and inwardly relative to said wheel face, a work holder adapted to hold a drill bit, said work holder having adjacent sides adj acent surfaces on the work 'rest whereby the .sur- 7 of the same angular relation as the faces on the work holder are adapted to cooperate with the surfaces on the work restto properly rinding wheel for grinding;

8. A drill bit grinder comprising a grind-- ing wheel, guiding means adjacent said grinding wheel, a work rest slidably mounted on said guiding means, a stop to limit the m ovementof vthe work rest, said work rest supporting surfaces meeting at -in a line which is inclined upwardly and inwardly relative-to the planeof rotation of the face of the grinding wheel, awork holder adapted vto hold a drill bit and with the side 5 a drill bit, meansto position the direction comprising a plurality of supporting surfaces angularly disposed to the plane of the face of the gri ding wheel, said supporting surfaces being arranged in pairs with one pair of a right angle surfaces of said holder meeting at right angles, saidwork holder being an independent block unattached to said work rest and with the surfaces on the work holder adapted to cooperate with the surfaces'onthe work restto properly present the faces of a drill bit .to the 'grinding wheel for grinding;

9. Devices for grinding drill bits comprising a tool holder'comprising an independent block-having supporting side surfaces and with a longitudinal opening to receive guiding means adjacent said,

supporting. surfaces meet ng at a line lnclined downpresent the faces of a drill bit to the I supportingv of extent of the cutting edges of the drill bit relatively to thesaid surfaces, a grinding wheel, meanscooperating with said surfaces on the tool holder to present said cutting edges of the drill bit'to, the grinding wheel a;

to sharpen said edges.

' l0. A grinding device for drill bits com prising a grinding wheel, abracket, a sup:

porting shaft carried by saidbracket, a Work rest mounted for reciprocatorymovement on said shaft, said work rest: comprising a plurality ofpairsof supportingsurfaces- 1nclined relative to the face of the grinding wheel, one of said pair of surfaces beinginclined in one direction toward the face of- I. "said wheel and the other, of said pair of, s-urfaces. being inclined in the opposite direction toward the face of-said wheel, a work holder having right, angularly disposed surfaces c0--' operating with said workrestvto present a: drill bit to said grinding wheel, and means to-guide a drill bit intoa'i definite predeter-f mined relation to saidwork holder. l 1.--A drill bit grinder comprising a grind-- ing wheel, guidingvmeans, a work rest slidably and rotativelymounted on said guiding means, said work rest having a plurality of supporting surfaces, a :bit holder adapted to cooperate with the supporting surfaces onf said work rest topresent a drill bit to the work face of the grinding wheel, said bit holder having a longitudinal-opening to receivethe shank of adrill bit, means to set a drill bit in the said opening with the lines of the cutting edges at right'angle's to the surfaces'on the work rest, and a stop to limit the movement. of said work wrest towards said rinding wheel.

12. A drill bit grinder comprising a grinds mg wheel, supporting means, a work rest rotatively mounted on said supporting means, a plurality of supporting surfaces on said work rest, means to retain said work rest in a predetermined rotative position on said supporting means to render a predetermined surface'effective relative to said.

grinding wheel, a toolholder adapted to hold I the, drill bit to be ground andto cooperate with the supporting face on the work rest to present cutting edges on the drill bit to the grinding wheel for grinding, and an adjustable stop mounted on said supporting means to limit the movement of said work rest to; ,ward the grinding wheel. 1 Y 13. A drill bit grinder comprlslng a grind- I ing wheel, a tool holder support, a tool holder adapted to hold the drill'bit to be ground, said tool holder having a longitudinal openingin which the drill bit may be rotated, means to set a drill bit into said tool holder with the edges of said bit set to cause said tool holder to presentcutting edges on the drillbit to the grinding wheel for correct grinding, means to look th e drill bit in the holder, and an adjust- Qeable stop to limit the movement of said tool holder toward the grinding wheel.

14. A drill bit grinder comprising a grinding wheel, a work rest slidably mounted for movement toward and from said wheel, said work rest comprising a plurality of supporting surfaces angularly disposed to the plane of the face of the grinding wheel, means on said work rest to direct a drill bit upwardly and inwardly relative to the planeof rotation of the face of the grinding wheel, and another means on said Work rest to direct said drill bit downwardly and inwardly relative to said wheel face, and stop means to limit the movement of said drill bit toward said grinding wheel.

ALBERT A. MARTELL.

Images