US2231217A - Machine for grinding tool bits - Google Patents

Description

Feb. 11, 1941. E. c. OLIVER MACHINE FOR GRINDING TOOL BITS Filed Feb. 6, 1939 5 Sheefcs-Sheet 1 INVENTOR.

ATTORNEY.

- Feb. 11, 1941. E. c. OLIVER 2,231,217

MACHINE FOR GRINDING TOOL BITS Filed Feb. 6, 1939 3 Sheets-Sheet 2 f//ff//f W Ez .5.

INVENT OR.

Edd ci. O//yf W i.' Gumv ATTORNEY.

Feb. 11, 1941. E. c. OLIVER MACHINE FOR GRINDING TOOL BITS 3 Sheets-Sheet 5 4 Filed Feb. 6, 1939 SNN . INVENTOR. Edd c. d/fyef 74, 4 f1/' ATTORNEY.

Patented Feb. ll, 1941' UNITED STATES PATENT OFFICE MACHINE FOB. GRINDING TOOL BITS Edd C. Oliver, Adrian, Mich.

Application February 6, 1939, Serial No. 254,847

8 Claims.' (Cl. 51-127) This invention relates to machines for sharpening tool bits to the same of a dei-mite standard shape as may be required for various characters of cutting tools and character of work to be cut. The object of the invention is to provide a machine having a grinding wheel or wheels and provided with means for the forming of a template corresponding exactly to a predetermined proportion to the shape to which the tool is to be ground and means utilizing a template to control the movement of the tool bit in relation to the grinding wheel to thereby form the cutting face or edge of the tool to the exact desired form. To this end a. further object of the invention is to provide a iixture for the positioning of the tool in predetermined relationship with a template preparatory to the grinding operation, a removable fixture for forming the template, and a grinding wheel dresser, all of which are interchangeably positionable relative to a grinding wheel and respectively utilized in the sharpening of the tool bit, grinding the template to form, and resurfacing the grinding wheel to maintain a true flat grinding surface and 2;, locating same in right relation with carriage,

wheel guard carrying knob and straight edge.

A further object is involved in the supporting of the xture in relation to the grinding wheel so that various angular positions of the tool bit 3o in respect to the grinding wheel may be attained as required in forming tool bits with different shapes of cutting edges. Thus the invention not only involves a'machine for the sharpening of tool bits but a machine in which a template may be formed to proper size and shape for use in the trueing or sharpening of a worn tool bit.

These and other objects and features of the invention are hereinafter more fully described and claimed, and the preferred form of construction of a machine embodying my invention is shown in the accompanying drawings in whichlig. l is a plan viewoi the machine. Fig. 2 is an elevation thereof taken from the lower side of Fig. 1.

Fig. 3 is an elevation thereof taken from the right hand side of Eig. 2.

Fig. 4 is an end view of a template.

Fig. 5 is a plan view thereof.

u Hereiofore. in the sharpening of tools, which are usually of a rectangular section, a considerable problem is involved in maintaining the shape of the tool and female gauges are utilized. the workman grinding the tool by-fhand and repeatedly itting it to the gauge in an attemptto insure the tool being ground to exact originalk shape. f

To avoid the cost of hand labor and secure greater accuracyr in grinding the tool blt to shape, 6a I have provided a machine as shownin the accompanying drawings for the grinding of tool bits to exact shape without the necessity o! use of the female gauges and insuring a. correct dupliacte of tools which are to be oi identical form.

The machine, in the preferred form shown, 5 consists of a base I at the upper end of which is a spindle 2 having on its respective opposite ends cupped grinding wheels 3 and 4. The spindle 2 is driven by a pulley 5 in the head of the machine directly belted by a belt 8 to a pulley 10 1 of a motor 6 mounted in the base. The grinding wheels are thus constantly driven in the operation of the machine. In front of the Wheel 3 is a guard I0 and in front of the wheel 4 is a similar guard 9 which, as will be understood 15 from Fig. 2, is shaped to expose a portion of the grinding wheel face in each case and against which exposed portion of the tool to be formed is to be held.

The wheel guards are each mounted on similar 20 carriages II for the wheel 3 and I2 for the wheel 4. The carriages are slidable on a square shaft I3 and movement of the carriages on the standard I3 is produced by means of a knob I4 for the carriage Il and I5 forthe carriage I2. The 25 knobs are each attached to similar screws, one of which is shown at I4al in Fig. 3. The screws each engage in a similarnut I6 xed in the respective ends of the square shaft I3 so that rotation of one or the other of the screw elements 30 by the knobs will move the respective carriage toward or from a common center line therebetween. The wheel guards are each formed with an arcuate base Il which rides in the similarly formed way I8 of the slides il and l2. 35

There is also an arcuate T slot I9 in each-carriage in which the head ,of a bolt 2B may swing in turning the wheel guard to any desired angle and the axis of movement intersects the line A to B. which is an axis of the spindle 2, and each 40 guard thus swings on an axis of equal length in the respective ways. The point of contact of the diamond dresser with the wheel is in a horizontal plane cuttingthe wheel axis and is shown as exactly half way between the knob 2l, shown 45 clearly in face view in Fig. 2, and the straight edge 22 at the upper end of the guard 9 though the upper Dart of the arm 3| may be longer or shorter as desired. There is a similar knob 23 on the guard 9 on the opposite side of the vertical 50 center line passing through the grinding wheel axis from that occupied by the knob 2l and a straight edge 24 is provided at the upper end of the guard aligning therewith. The angle of tilting of the wheel guard is indicated by the scale 25 55 shown at the left side of Fig. 3, a similar scale being provided for both the wheel guards, and when the wheel guard has been tilted toa predetermined degree it is xed by means ois, handle 26 for the guard I 0 turnable in the base of the so wheel guard. Within the said base an eccentric cam 21 rotatable in a nut 28 for the bolt 20 with which it is in threaded relation. handle 26 is turned to release the pressure on the bolt head in its Way, the guard may be freely tilted and then locked by rotation of the handle in an opposite direction to move the nut upwardly in the recess in the base provided therefor ta thereby clamp the nut in its way. Thus the wheel guard may be adjusted to a angle shown on the scale and rigidly held in position. The center of the knob 2|, the grinding point of the wheel on the line B and the face of the straight edge 22 are exactly in line when the clearance angle is anything else than zero, and the diamond dresser is used the line followed by the diamond is exactly the same line traversed by the tool edge in the grinding thereof and the surface of the wheel produced by the diamond is exactly in line with theball and the straight edge. There arelthreeA xtures utilized with the machine-namely, the xture 29 shown at the right side of Fig. 2, 30 shown at the left side of Fig. 2 and 3| shown on the face of the machine extending across the face of the wheel. The fixture 3| is the wheel dresser which has a depression at its lower end to t the knob 2| and has a diamond dresser 32 shown more clearly in Fig. 2, which is exactly one-half way between the element 34 and the knob 2|. The wheel dresser has a. handle" element 33 and at the top a short end portion 34 which ts against the straight edge 22. The grinding wheels may be dressed with wheel dresser in position on wheel guard by feeding carriage in until the diamond dresser 32 comes into contact with face of wheel, then carriages |I and I2 must be locked with clamp screws 63 and 64. Never move carriages unless for dressing wheels. This fixture, as previously stated, is removable and one of the other fixtures may be mounted on the knob 2| in place of the Wheel dresser.

The fixture 29, for instance, shown at the right hand side of Fig. 2, is for holding the tool and a template. With this fixture, a template of twice the desi-red size to which the tool is to be ground is positioned in the top of the fixture as is shown at 35 in Fig. 2. The upper end of the xture at least is formed of two spaced parts 36 and 31 and has wedge shaped grooves at the top to receive the template 35, the screw 38 being provided to securely clamp the template in place when adjusted.

It will be noted from Figs. 1 and 2 particularly that the template 35 is set with its outermost point in engagement with the vertical plane face of the knob 39 and is clamped in place by means of a screw 38 which draws the two side bars 36 and 31 together. 'Ihe knob 39 has a Vernier 4| thereon and is threaded in the portion 42 of the wheel housing 41. If it is desired to remove .010 from the tool bit the knob is turned out until .010 shows opposite the zero mark at 43. Then, as the template 35 is held against the vertical surface of the knob, the tool bit shown at 44 in Fig. 2 is pushed inwardly against the flat finished surface 45 provided on the knob 46 formed on the wheel housing 41. The tool bit is then clamped in place by means of the screw 48 and the lever 4 9 which holds the bit in the seat provided therefor in the element 50. y When this adjustment has been made, the fixture 29 with its template and tool bit are removedefrom the position shown in Fig. 1 where it is seated) at its lower end on a knob 5|.

This end of the xture 29 is then placed on the knob 2| and the template 35 in position for en- When the Y gagement withthe surface 22 while the tool bit itself will engage the wheel at the same point as occupied by the wheel dresser 32 when the wheel dressing xture has been removed. With the template 35 opposite the straight edge 22, the tool bit will engage the wheel until it has been ground sumciently to permit the template to contact the straight edge. The xtur is to be rocked on the ball end 2| during the grinding so that all points of the cutting edge will contact the wheel until suiicient metal has been removed to permit contact of the template with the straight edge. Further lrocking of the xture produces a shape on the tool bit corresponding to the shape of the template except that the nished tool bit will be one-half the size of the template.

The tool may be ground with a clearance by loosening the handle 26* for the guard 9 or 26 for the guard I0 as the case may be and moving the indicator 25 shown at the left side of Fig. 3 to the desired degree. It is also to be understood that a similarindicator is provided on the base I1 of the wheel guard I0. The indicator is moved to `show the clearance angle on the scale and this brings the wheel guard at the required angle to the wheel to provide for grinding the proper clearance.

What I have hereinbefore termed .Wheel guards 9 and I 0 which practically cover the periphery Vof the wheel and a, portion of the face thereof may, in so far as the invention herein described is concerned, be merely frame elements having the arcuate bases, ball knobs 2| and 23 and straight edges 22 and 24 for the guard 9 and ball knobs 2 Ia and 23a and straight edges 22u and 248 for the guard I0 and both are adapted to be tilted about a point in a plane cutting the horizontal axis of the grinding wheel.

A template may be made with the machine of a size twice the size of the tool and usable in the xture 29 in the regrinding of like tools. The template forming xture is shown at 36 and is constructed at the upper end similar to the upper end of the xture 29 in which a. template blank 52, shown in Figs. 4 and 5, is clamped by means of a screw 53 similar to the screw 38 of the xture 29. The ixture 3|) includes a base 54 having a socket for the fulcrum knob 55 and also has intermediate its ends a holder 56 for a tool 51. 'I'he tool is a new tool of accurate form, for instance the form indicated by dotted lines 58 o1 Fig. 5. The tool is mounted in the xture 30 and the xture placed on the knob55 as shown in Fig. 2 with the forward end 59 of the template in engagement with a finished face of the lug 60 and with the tool in engagement, with the nished face of the lug 6| on the side of the machine which faces 'are in vertical alignment with the axis of the ball knob. 55 on which the xture may turn. When the tool has thus been adjustably xed in place, the xture 30 is removed from the knob 55 and placed on the ball knob 23 of Fig. 2.

It is to be noted that the distance from the template 52 to the axis of the socket 55 of the xture 30 is equal to the distance from the center of the knob 5| to the point of engagement of the tool 44 with the face 45 of the lug 46 and that thepoint of the tool` 51 is half way between the template 52 andraxis of the socket 55. Thus, when the iixture 30 is mounted on the knob 2l, the iinished tool edge will contact a finished face of the lug 6|* on the leftv side of the machine or lug 62 on the right side of the machine if the xture 30 lbe mounted on the knob 2|. Thus when the iixture 30 is mounted on the knob 23 or 2l the edge of the tool 51 engages the lug 9|* or 62 and the template 52 is in position to engage the grinding wheel face which is aligned with the axis of the knob 23 and by rocking the xture 5 on the knob the template isl ground away to the extent permitted by reason of engagement of the tool with the surface BI.

Whatever the form of the tool, for instance the form indicated by the dotted line 5I of Fig. 5, the template will be of the same form but twice the size and thereby adapting the template for use in the iixture 29 for the regrinding of tools to conform exactly in ysize and shape tothe cutting face of the tool 51 which is used as a pattern therefor and is one-half the size of the template used for determining the shape of the same in the xture 29.

It is thus tobe seen that the various objects and features of the invention areattained-by the structure described by means of which the tools may be sharpened to conform to a template or a template can be made to conform to the shape of an original and unworn tool and utilized in the fixture 29 for the regrinding of tools. The fixtures are interchangeable in position. The fixture' 29 may be placed in the position occupied by the wheel dresser 3| in Fig. 2 in which' v case the edge of the tool -to be ground is on a horizontal line with the axis of the wheel at the point 32. In view of the fact that the knobs 5l and 55 are in horizontal alignment the ilxture 29 can b e utilized on the knob 55 and in relationship to the micrometer adjusting means indicated generally at 59a as the face of the lug 60 is horizontally aligned with the face 45 of the lug 46 shown in Fig. 2. The template forming fixture 30 can be used either on the knob 55 or 5I. The machine is provided with two grinding wheels and both wheel guards have the pairs 40 of knobs 2l and 23 as shown on the guard 9 in Fig. 2 and are otherwise preferably duplicate in form.

The purpose of using two grinding wheels resides in the fact that the machine is made primarily for tool bits having tungsten carbide linserts and it is necessary to use two types of wheels, one for roughing and the other for finishing the tungsten carbide. However, other types of the tool bits may be ground and the two wheels are used because it is desirable to' rough out the tool with a coarse wheel and then finish the cutting edge on a liner wheel.

As will be noted more particularly from Fig. 3, the wheel dresser has a depression at its lower end'and the center of this depression the point of the diamond 32 and the side of the contact piece 34 are in a straight line. When the wheel is dressed, this brings the face of the wheel in proper relation to the carriage and wheel guard 00 or frame element carrying the knob 2l and` straight edge 22, regardless of the angle at which it is set within the range of the scale 25, and

this vrelation is maintained until the wheel wears away to the point where it has to be dressed again. The dressing of the wheel to get this relation is very important in order to insure accurate operation of the device.

I have described the dressing diamond 32 as being exactly one-half way between the knob 2l and the member 22. However, the portion of the fixture 3i abovethe member 32 may vary to a greater or less degree if desired. For instance,

.g this upper portion of the fixture 3| could be twice the length of that shown but in order to operate properly the other fixtures would have to be changed proportionately. For this reason, the claims are not limited tothe parts being twice or half the length of the other parts which is the relationship of the parts shown in the drawings.

Having thus fully described my invention, its utility and mode of operation, what I cla and desire to secure by Letters Patent of the nited States is: v

1. A machine for the sharpening of tools to a predetermined contour, comprising a rotatable grinding wheel, a frame member mounted to turn on an axis located in a horizontal plane cutting the axis of rotation of the grinding wheel, said frame element including a knob element and a straight edge surface equi-distantly disposed on opposite sides of the said axis, a xture having a socket at one end to mount on the knob, means for supporting a tool therein, and a template having a face shape of the contour to which the tool is to be ground and twice the size of the tool, the template and socket axis of the fixture being on the opposite sides of the tool, the templatebeing engageable with the straight edge as the tool is ground and providing a structure wtherein the rocking of the fixture on the knob presents various points of the edge of the tool to engagement with the grinding wheel to finally shape the tool in correspondence with the face of the template in engagement with the straight edge.

2. In a machine for the grinding of worn tool bits to original form, a base having a head, a shaft rotatably mounted therein, a grinding wheel on the shaft, a frame element supported adjacent the grinding wheel face and tiltable at various angles relative thereto, means for forming a template corresponding to the shape to which the tool is to be ground, a fixture having a socket at one end and carrying the template at the other, and means for supporting a worn tool half way between the socket and the template in the said fixture, a ball like element in fixed position on the tiltable frame on which the socket of the :fixture may be positioned, a `straight edge face provided on the said frame for engagement by the nished template, means for adjusting the worn tool in the fixture to provide for a predetermined depth of grind of the tool, the said straight edge face, the face of the grinding wheel at the point of contact of the tool therewith and the fixed ball like element being an alignment and providing a construction wherein the positioning of the socket end of the fixture on the ball like element-and the template being urged toward the said straight edge, the tool is ground and, as the template engages the straight edge, the rocking of the fixture on an axis parallel with the face of the wheel presents the various portions of the face of the tool to the grinding wheel as determined by contact of the template with the straight edge.

3. In a machine for sharpening worn tool bits and the like to original contour, comprising a frame, a grinding wheel rotatably supported therein for rotation on a horizontal axis, a iixture for holding the tool bit having at one end a template having a contour desired to be formed on the tool and at the opposite end a socket, the tool bit` being positioned exactly centrally between the template and the axis of the socket, a frame element carried by the machine and tiltable relative to the face of the grinding wheel, the axis of the tilt of the frame element being in a plane cutting the longitudinal axis of the grinding wheel, means for supporting the fixture on the template engaging the straight edge shaping the tool edge to correspond to the contour of the template, said frame element being adjustable to permit the tool to be cut with a face at a right angle to the body of the tool or at a predetermined lesser angle.

4. In a machine for grinding the cutting edge of a worn'tool'bit to original form, a base, a rotatable grinding wheel having a iiat face, a template forming xture having a socket at one end, means at the opposite end for holding a template blank, said iixture including means Afor -holding a tool bit of the original predetermined form centrally between the template land the axis of the socket of the fixture, a ball like element in fixed position on the machine and a pair of lugs each having a iinished face in alignment with the axis of the ball, one of the lugs being equi-distantly positioned between the other lug and the ball like element, the spacing of the lugs and ball like element on the machine being exactly equal to the spacing of the template, the tool and socket of the fixture whereby, in the positioning of the xture on the ball like element, the edge of the tool bit engages the face of the intermediate lug as the template engages the finished face of the other lug, a second ball like element on the machine, a lug on the machine having a finished face aligning with the axis of the second named ball `like element and the face of the grinding wheel whereby the positioning of the fixture on the second named ball like element on the machine positions the cutting edge of the tool on the finished face of the lug as the template is brought to engagement with the grinding wheel and providing a means for forming a template with a contour twice the size of the contour and shape of the cutting edge of the tool.

5. A machine for the sharpening of worn tool bits, comprising a frame having a standard and a head, a shaft rotatably mounted in bearings provided in the head, a grinding wheel supported on an end of the shaft exteriorly of the head, a tiltable frame element a shaft like element carried by the frame on which the tiltable frame is longitudinally adjustable toward or from the grinding wheel face, the tiltable frame element being turnable relative to its support to vary its angular position relative to the face of the wheel, means on the frame for supporting a fixture providing a ball and socket relationship of the xture and the frame, the xture carrying the tool and a template, the template and socket of the fixture being equi-distantly. spaced on opposite sides of the tool, means on the machine for adjusting the tool in the fixture to provide for grinding of the tool to a predetermined degree,

the iixture positioning the tool in a horizontal plane cutting the axis of the wheel and axis of turning of the tiltable frame, said tiltable frame having a flat face portion engageable by the template as the tool bit is ground and through rocking movement of the fixture the contour of the Y angle to the face of the wheel whereby,

cutting edge of the' tool is ground to the contour of the template, the contour of the template being reproduced on the tool at one-half the size of the template contour.

6. In a machine for the grinding of worn tool bits, afram'e, a rotatable grinding wheel having a fiat face, a fixture including a template at one end, a means for holding the tool, and a socket at the opposite end, a ball-like element on the machine for the said socket, the axis of which is in the extended plane of the grinding wheel face, a straight edge surface in fixed relation with the ball element for engagement with the template when the socket is mounted on the lball and the worn edge of the tool positioning in engagement with' the grinding wheel, the rocking of the fixture on an axis parallel with the face of the wheel and with the template in contact with the straight edge presenting various portions of the tool edge to the grinding wheel to form a cutting edge corresponding to the face of the template engaging the straight edge.

7. In a machine for the sharpening of tools t0 a predetermined contour of cutting edge, a frame member, a grinding wheel supported by the frame and having a at face, means for rotating the grinding wheel, a fixture for holding a tool to be ground, a template carried by the xture at a distance from the edge of the tool, a socket on the fixture, the tool positioned between the socket and the template, a ball like element on which the socket of the xture is mounted to be rocked, and a straight edge surface engageable by the template positioned at a point distant from the plane of the wheel axis equal to the distance of the ball therefrom, the axis of grinding wheel contacted by the tool being in the same plane, a wheel dressing fixture having a socket at one end, a portion at the opposite end for engaging the straight edge surface and being mountable upon the ball like element, and a grinding wheel dresser at a point equi-distantly positioned therebetween to engage the face of the grinding wheel at the point to be contacted by the tool and exactly aligned with the axis of the ball and straight edge surface.

8. In a machine for the sharpening of tools to predetermined contour, a frame member, a grinding wheel having a fiat face, means for rotating the grinding wheel, a fixture for the holding of the tool to be ground, a template carried by the xture at a distance from the edge of the tool, a socket the axis of which is the same distance from the said tool edge on the opposite side of the tool from that occupied by the template, a tiltable frame element providing a guard for the grinding wheel, a knob on the said tiltable frame at one side of the axis of the grinding wheel and a straight edge surface on the tiltable frame equi-distantly spaced from the wheel axis on the opposite side from that occupied by the knob, means for adjusting the angle of the frame element to position the line from the straight edge to the knob at a predetermined when the fixture is mounted on the said knob, the tool is positioned at said predetermined angle to the face of the wheel and the rocking of the xture with the template in engagement straight edge shapes the tool to predetermined contour and angle of clearance.

EDD C. OLIVER.

edge being equi-distantly with the the socket and face of the

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