US3397492A - Drill bit grinding accessory - Google Patents

Description

0, 1968 B. c. WILSON 3,397,492

DRILL BIT GRINDING ACCESSORY Filed March 28, 1966 2 Sheets-Sheet l mmmlim INVENTOR. ERMA 6'. MAS'O/V 4770/?MEV 1968 B. c. WILSON 3,397,492

DRILL BIT GRINDING ACCESSORY Filed March 28, 1966 2 Sheets-Sheet 2 INVENTOR. BAm/V C- W/L SON izzww ATTORNEY United States Patent 3,397,492 DRILL BIT GRINDING ACCESSORY Bryan C. Wilson, 23228 Edmonds Way, Edinonds, Wash. 98020 Filed Mar. 28, 1966, Ser. No. 542,427 4 Claims. (Cl. 51-219) ABSTRACT OF THE DISCLOSURE A drill bit support to present and to position a drill bit for grinding and sharpening by rotary driven grinding wheel and at the periphery thereof. A substantially horizontal supporting surface and a drill bit holding and positioning carriage slidably and pivotally mounted on said horizontal supporting surface by an open pivotal connecting means, and wherein such carriage comprises an externally threaded rod having a longitudinally extending V-shaped slot to support the drill bit during sharpening. In connection with said V-shaped slot, there is provided a drill bit end stop slidable therein, and an internally threaded gauge connected with said rod and also slidably connected with said stop to position the stop longitudinally of said V-shaped slot.

My invention relates to improvements in drill supporting means for presenting the drills, as twist drills, to a rotary driven grinding wheel to grind and thereby to sharpen the drill bits.

One of the principal objects of my invention is to provide a grinding wheel attachment for use in connection with a conventional rotary driven grinder and which attachment is simple in construction, economical, easy to apply and install, and one which produces, with reasonable care, exceedingly accurate results in bit grinding.

Prior art structures designed to regrind or to sharpen drills have had such an initial cost and have required such skill in use, that it has become common practice for drill users to rely on individual skill to sharpen the drills by sight calculations only, with the drill resting on a fixed support. However, many persons did not possess the needed skill and the results have become so inaccurate that, commonly, drills are thrown away rather than resharpened when it has been found that the drills are not operating efliciently. I

It is well known in shop practice that in order to obtain maximum eificiency and life of the drill points that the cutting edges must be substantially identical in longitudinal projection and contour and substantially identical as to the angle of lip clearance or relief cut away from the cutting edges. Any lack of uniformity in these respects results in one cutting edge of the two or more cutting edges on the drill to do all of the work or all of the cutting and with very rapid deterioration in the efiiciency of the drill bit.

It is a primary object of my invention to provide a drill grinding accessory or attachment which can be readily secured to the fixed supports which are commonly available and present in connection with rotary grinding wheels.

It is another primary object of my invention to provide a base supporting means comprising two plates, the lower of which is connectible to the usual fixed support found with grinding wheels and the upper of which is relatively angularly adjustable thereto. Thus, the angle of the ground face of a bit, relative to its longitudinal axis, supported by attachments of my invention, can be readily determined.

Another object of my invention is to provide a separable drill bit support which is mounted for sliding movement relative a base supporting means and wherein there 3,397,492 Patented Aug. 20, 1968 is a separable pivotal connecting means between the drill bit carriage and the base supporting means.

It is a further object of my invention to provide such a separable pivotal means which is offset relative to a radial alinement of a drill bit and a grinding wheel so that upon turning about the pivotal connection, with one swinging movement, the drill bit cutting edge is cut and the relief lip, or the receding away surface from the cutting edge on the drill bit ground face, is provided to a desired pattern so that after one drill bit face is ground, succeeding faces can be ground to the same contour pattern and dimension and with the need of minimum skill on the part of the operator.

These and other objects of my invention and advantages thereof will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same parts, and, in which:

FIGURE 1 is a side elevational view, with parts broken away, of a device embodying my invention;

FIG. 2 is a plan view of the structure of FIG. 1, with parts broken away, and with the drill bit support positioned to aline a drill bit therein substantially radially of the grinding wheel or at right angles to the axis of the grinding wheel;

FIG. 3 is a view similar to FIG. 2 with the drill bit support angularly moved substantially over its showing in FIG. 2;

FIG. 4 is a fragmentary elevational view taken substantially on broken line 4-4 of FIG. 1;

FIGS. 5, 6, and 7 are sectional views taken substantially, respectively, on broken lines 55, 66, and 77 of FIG. 1;

FIG. 8 is an enlarged fragmentary view, taken substantially on broken line 8-8 of FIG. 2, and showing a fragment of a grinding wheel and a bit being sharpened at the commencement of the grinding of a drill bit face and corresponding substantially to the same position of the parts as indicated in FIG. 2 of the drawings;

FIG. 9 is a view similar to FIG. 8, taken substantially on broken line 99 of FIG. 3, and after the drill bit carriage has been moved substantially to the position shown in FIG. 3 of the drawings;

FIG. 10 is a fragmentary plan of substantially the same parts shown in FIGS. 8 and 9; and

FIG. 11 is a frontal view of the sharpened end portion of a drill bit.

Referring now to the drawings, a conventional rotary driven grinding wheel mechanism is illustrated by a base 20, motor housing 22, safety guard 24, adjustable tool support 26, and grinding wheel 28. The grinding wheel 28 is driven by any suitable electric motor within the motor housing 22 and is normally driven in a clockwise direction as viewed in FIG. 1 of the drawings.

Thus, there is provided a rotary grinding wheel having an annular grinding surface and the axis of which grinding wheel normally lies substantially in a horizontal plane. Disposed in fixed relation, when in use, is the tool support 26. Thus far conventional apparatus is illustrated and described and it is in connection with such conventional apparatus that the attachment or accessory of my invention may be utilized.

While the adjustable tool support 26 is commonly provided with many adjustments which may be utilized and then the adjustments fixed, normally such adjustments do not provide for movements within the range desired in my invention. Thus, to a fixed support 26, I detachably secure a base support comprising two hingedly interconnected plate members 30 and 32. The plate member 30 may be the lower plate member and may be detachably connected by any suitable means, such as C-clamps 34, to any suitable portion of the adjustable tool support 26.

The means for hingedly interconnecting plate members 30 and 32 may be in the form of laterally spaced apart flanges 36 carried by the plate member 30 and laterally spaced apart flanges 38 depending from the plate member 32. The flanges 36 may be integral with the plate 30 and bent at an angle thereto of approximately 90 and likewise the flanges 38 may be integral with the plate member 32 and bent downwardly at substantially right angles thereto. The flanges 36 and 38 are interconnected by nut and bolt means wherein one of the same is in the nature of a wing nut or a bolt having a wing head thereon for easy manual manipulation. Thus, I have illustrated nuts 40 and bolts 42, where the bolts 42 have wing portions 44 and the bolt portions of the bolts 42 function as a pivot means so that any desired angular adjustment between the plates 30 and 32, within the requirements of the accessory, may obtain and after such adjustment is determined, the nuts and bolts 4042 may be locked to maintain a desired angular position of the substantially horizontal upper surface of the plate 32. The plate 32 is positioned relative to the grinding wheel 28 by the use of the various attachments involved in the normal adjustable tool support 26, the C-clamps 34, and the adjustment of the base support comprising the plate members 30 and 32. A drill bit holding and positioning Carriage 52 (hereinafter described more in detail) includes a plate member 46 and such plate 46 (and in turn the drill bit holding and positioning carriage) is connected by a separable pivotal connecting means with the plate member 32. As illustrated, the separable pivotal connecting means comprises a pin 48, which pin 48 is carried by the plate 32. A separable bearing engaging with said pin 48 is indicated in the drawings as a V-shaped slot 50 in the plate 46. The pin 48 may be carried either by the plate 32 or 46 and the slot or hearing to rest against the pin may be carried by the other of said plates 32 and 46.

When the longitudinal axis of the drill bit holding and positioning carriage 52 is radially alined with the grinding wheel 28 (when said axis is at right angles to the axis of grinding wheel 28) then the axis of the pin 48 is offset laterally. Thus, in FIG. 2 of the drawings the axis of the pin 48 is shown lower than the longitudinal axis of the drill bit carriage member 52. Thus, when the drill bit carriage 52 is swung from the position shown in FIG. 2, to the position shown in FIG. 3 of the drawings, the drill 54 in the carriage 52 will move from the position shown in FIG. 2 or FIG. 8 of the drawings to the position shown in FIG. 3 or FIG. 9 of the drawings. Such swing is accomplished by the relative sliding movement between the contacting faces of plates 46 and 32 and with movement pivoted about the axis of the separable pivotal connecting means comprising the pin 48 and the V-shaped slot 50.

The drill bit carriage also includes an externally threaded rod 56 secured to the plate 46 and such may be readily accomplished by welding. The said externally threaded rod 56 is provided with a longitudinally extending V-shaped slot 58, the contour of which is best illustrated in the sectional views, FIGS. 5, 6, and 7. This V-shaped slot 58 functions as a cradle to center and slidably support a drill bit 54 placed therein. Also, a sliding carriage 60 is mounted for sliding travel in said V- shaped slot 58.

The carriage 60 is provided with a head portion 62 (see FIG. a recessed portion 64 (see FIG. 6), and a trailing portion 66 (see FIGS. 1 and 7). Thus, an internally threaded circular adjusting gauge 68 may pass over the trailing edge portion 66 (before the parts are otherwise assembled) and into the recess portion 64. Then as the internally threaded adjusting gauge 68 is threaded onto the external threads of the externally threaded rod 56, the said gauge 68 (upon rotation in one direction) will urge the carriage 60 toward the left in the drawings as the forward surface of the gauge 68 engages the rear face of the head 62 and will urge the carriage 60 toward the right in the drawings as the rearward surface of the gauge 68 engages the forward portion of trailing portion 66.

To utilize the accessory of my invention, first the adjustable tool support 26 is suitably adjusted and its position fixed, and then the lower plate member 30 is attached by C-clamps 34 (or other suitable means), to the adjustable tool support 26. Then the drill bit carriage 52 is moved into place so that the V-shaped slot engages with the pin 48 carried by the plate member 32. A drill bit 54 is then positioned within the V-shaped slot 58 and ahead of the head 62 of the sliding carriage 60. The drill bit 54 is moved with its cutting surfaces toward the annular surface of the grinding wheel 28 and an adjustment is made so that one of the cutting edges of the drill 54 is presented to the surface of the grinding wheel 28 and at a desired angular relation thereto. To grind the relief lip 72 and cutting edge 70 (see FIGS. 8 to 10) with one positioning of the drill 54, the cutting edge 74 is positioned in a vertical plane (see FIG. 10). Then all adjustments are fixed to retain such adjustment, including tightening of the nuts and bolts 40-42. Then the sliding carriage is adjusted so that the drill bit portion to be sharpened is not in engagement with the grinding wheel 28 and then the grinding wheel 28 is caused to rotate.

A cutting edge and relief lip (as 70, 72) of the drill bit 56 to be first ground is presented to the grinding wheel 28 by tuming of the gauge 68 and with the trailing end of the drill firmly against the head 62 and with the cutting edge 74 in a vertical plane as shown in FIG. 10. After the first edge is thus ground to provide the cutting edge 70, the drill 54 is held firmly in the V-shaped slot 58 and the drill bit carriage 52 is swung from the position shown in FIG. 2 of the drawings to the position shown in FIG. 3 of the drawings, and at the same time the drill cutting edge moves relative to the grinding wheel 28 from the position shown in FIG. 8 of the drawings to that position shown in FIG. 9 of the drawings. Thus, it will be apparent that the relief lip 72 is ground as the drill bit carriage 52 turns about an axis determined by the pin 48 and the bearing for said pin provided by the V-shaped slot 50. As the plate 46 .angularly moves about pivot means determined by pin 48 and slot 50, the end of the drill bit being sharpened moves in the path described by the circular line 75. Thus, either the relief lip 72 may be ground first or the cutting edge 70 may be ground first as both are ground to an arcuate path designated by line 75. As the angular position of the drill 54 locates the location of the grinding of cutting edge 70 and relief lip 72, the angular position of drill 64 is accurately determined by positioning of cutting edge 74 in a vertical plane as shown in FIG. 10.

The angularity of the cutting edge 70 to the longitudinal axis of the drill bit 54 was selected and determined by the adjustments of the adjustable tool support 26 and the adjustment between the plate members 30 and 32. This adjustment is maintained after the same is once determined for grinding all of the cutting edges of a given drill bit. I

After one of the cutting edges of a given drill has been made, a subsequent cutting edge may be ground on the same drill bit and which will match the first cutting edge as the head 62 is not touched or moved between the grinding of one of the cutting edges 70 and the grinding of a subsequent matching cutting edge 74. An advantage of having a separable pivotal connection between the plate 32 of the then fixed support and the plate 46 of the drill bit carriage 52 is that after grinding the first cutting edge 70 and the relief lip 72, the drill bit carriage 52 may be entirely removed and the drill (if a two-fluted twist drill) turned (and with the cutting edge 70 now in a vertical position as respects FIG. I0) and then the plate 46 rested upon the plate 32 and the drill bit carriage 52 moved toward the grinding wheel 28 when the parts are in the relative position shown in FIG. 2 of the drawings and moved forward until the V-shaped slot 50 rests firmly against the pin 48. The relative position of the sliding carriage 60 to the grinding Wheel 28 may be maintained and such will permit the second or subsequent cutting edge 74 to be ground identical to the cutting edge 70. Also, by pivoting the drill bit carriage about the pivot means, pin 48 and V-shaped slot 50, the same contour will be provided to the relief lip 76 for the second cutting edge 74 as was provided in connection with the relief lip 72 for the cutting edge 70. Also, in view of the grinding to the circular line 75, no care is needed in presenting the cutting edge 74 and relief lip 76 to the periphery of the grinding wheel 28.

From the foregoing it will now be obvious that I have provided a drill grinding attachment for use in connection with a rotary grinding wheel illustrated by the grinding wheel 28, which has an annular grinding surface to be employed primarily in regrinding drill bits. Twist drill bits having a plurality of cutting edges are illustrated by drill 54 having cutting edges 70 and 74 and relief lips 72 and 76. Such conventional grinding wheels are provided with an adjustable support illustrated generally by 26 and which when in use becomes a fixed support which is in operative position relative to the grinding wheel 28. In my invention the attachment comprises a base support which is detachably connected to the fixed support and wherein said base support preferably comprises the plates 30 and 32 which are detachably connected to the fixed support and which plates 30 and 32 are hingedly interconnected as by nuts 40 and bolts 42 to thus provide a substantially horizontal supporting surface by the plate 32.

Next, I provide a drill bit holding and positioning carriage 52 which includes therein the plate 46 which is slidably mounted on the horizontal supporting surface 32. The connection, between the horizontal supporting surface 32 and the plate 46 of the drill bit holding and positioning device 52, is preferably a separable pivotal connecting means including a pin, as 48, and pin receiving bearing, such as V-shaped slot 50. As illustrated, the pin 48 is carried by the plate 32 and the pin receiving bearing 50 is carried by the plate 46. However, it is only necessary that the pin 48 be carried by one of said members and the pin receiving bearing 50 by the other thereof to provide for a separable pivotal connecting means between the drill bit holding and positioning device, as 52, and the horizontal supporting surface, as plate 32.

Next, the axis of the pivotal connecting means is relatively offset from the alinement illustrated in FIG. 2 of the drawings where the longitudinal axis of the drill bit holding and positioning carriage 52 and the drill bit 54 therein is alined with a plane at right angles to the axis of the grinding wheel 28 or as it may be stated, in the plane radial to the grinding wheel 28. By having such offset, the drill bit holding and positioning device 52, as well as the drill bit 54 carried thereby, may be swung from the position shown in FIG. 2 of the drawings to the position shown in FIG. 3 of the drawings which in turn provides the relative motion between the drill bit 54 and the grinding wheel 28 which is illustrated by the change from FIG. 8 to FIG. 9 of the drawings. When the parts are in the position shown in FIG. 8 of the drawings,- the cutting edge 70 of the drill 54 is ground and as the plate 46 is swung about the axis of the pin 48, the drill bit moves from the position shown in FIG. 8 of the drawings to the position shown in FIG. 9 of the drawings and the relief lip 72 is cut.

Preferably, the drill bit holding and positioning carriage 52 comprises an externally threaded rod 56. Preferably, the threads should be relatively large in number per inch and precisely fitted to the internal threads of gauge 68, which will minimize any tendency of the gauge 68 to turn on rod 56 because of vibration which may result from contacting of the drill 54 with the annular surface of the grinding wheel 28.

Next, the externally threaded rod 56 is Preferably provided with a V-shaped slot 58 for carrying and centering of a drill 54 therein.

Lengthwise movement of a drill 54 in the slot 58 and predetermining of a position therein obtains by reason of the sliding carriage 60 which comprises the head 62, the recess portion 64, the trailing portion 66, and the adjusting gauge 68, the latter being internally threaded, carried in the recess portion 64, and threadedly connected with the external threads of externally threaded rod 56. The said gauge 68 is rotatively mounted in the recess portion 64. I believe that the mode of operation of the parts of my invention will be either explicit or inherent and implicit in the foregoing without further detailed description.

Obviously, changes may be made in the forms, dimensions and arrangements of the parts of my invention without departing from the principle thereof, the above setting forth only a preferred form of embodiment of my invention.

What I claim is:

1. A drill grinding attachment for a rotary grinding wheel having an annular grinding surface, the axis of which lies substantially in a horizontal plane and a fixed support operatively positioned relative to the grinding wheel peripheral surface, comprising a base portion detachably connected to said fixed support and providing a substantially horizontal supporting surface; a drill bit holding and positioning carriage slidably mounted on said horizontal supporting surface, said carriage comprising an externally threaded rod having a longitudinally extending V-shaped slot, a drill bit end stop, and an internally threaded gauge, slidably connected with said drill bit end stop and threadedly connected with said externally threaded rod; and an open pivotal connecting means between said carriage and said horizontal supporting surface permitting sliding movement of said carriage on said 'horizontal supporting surface about the axis of the pivotal connecting means, the said axis lying substantially in a vertical plane and laterally offset from a plane passing through the longitudinal axis of a drill bit on said carriage and passing substantially radially of said grinding wheel.

2. The combination of claim 1 wherein said carriage has a gauge receiving recess and said gauge is mounted for rotary movement as respects said recess.

3. The combination of claim 1 wherein said open pivotal connecting means comprises a pin and registering open slot pivotally interconnecting said supporting surface and said carriage.

4. The combination of claim 4, wherein said pin is carried by said supporting surface, projects upwardly therefrom, and is engageable with an open slot provided in said carriage.

References Cited UNITED STATES PATENTS 388,784 8/ 1 888 Mossberg 5 1-96 X 2,119,741 6/1938 Fischer 5l96 X 2,313,641 3/ 1943 Hoerst '5 12"19 2,371,676 3/ 1945 Coyne 51-219 2,401,471 6/ 1946 Fendring 51-219 FOREIGN PATENTS 277,754 12/ 1951 Switzerland.

HAROLD D. WHITEHEAD, Primary Examiner.

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