US2912971A - Diamond dressing tool assembly - Google Patents

Description

Nov. 17, 1959 Filed May 22, 19 68 H. C. MILLER v DIAMOND DRESSING TOOL ASSEMBLY 2 Sheets-Sheet 1 .INVENTOR.

HAROLD C. MILLER ATTY.

Nov. 17, 1959 H. c. MILLER 2,912,971 mmvxoma DRESSING TOOL ASSEMBLY Filed May 22, 1958 2 Sheets-Sheet 2 INVENTOR. HAROLD C. MILLER AfTY.

United States Patent DIAMOND DRESSING TOOL ASSEMBLY Harold C. Miller,- Chicago, Ill., assignor to Super-Cut, Inc., Chicago, 111., a corporation of Illinois Application May 22, 1958, Serial No. 737,031 11 Claims. (Cl. 125-39) The present invention relates to apparatus for dressing abrasive grinding wheels or the like and it has particular reference to a novel combination of a tool and tool holder assembly wherein the tool consists of a shank having mounted therein a diamond dressing stone adapted to be presented to a rotating grinding wheel for dressing purposes, the dressing action taking place in either direction of traverse across the surface of the wheel. Specifically, the invention is concerned with a diamond-carrying mount or tool and a cooperating holder therefor of novel construction by means of which the diamond dressing stone associated therewith may be applied to the rotating surface of the grinding wheel at selected regions on the surface of the diamond and in selected vectorial directions relative to the crystallographic structure of the diamond on the one hand, and in selected directions relative to the rotating surface undergoing truing on the other hand to produce maximum resistance to abrasion on the part of the dressing stone and to produce maximum dressing effect on the surface undergoing treatmerit.

In a co-pending application of LeopoldH. Metzger and Harold C. Miller, Serial No. 664,570, filed on June 10, 1957, for Method of and Apparatus for Dressing Grinding Wheels, there has been shown and described a diamond-carrying mount and a holder therefor by means of which a diamond dressing stone may be applied to the rotating surface of a grinding wheel at such selected regions and in such selected vectorial directions, and the diamondcarrying mount and holder of the present invention is designed as an improvement over the mount and holder shown in the above-identified application, the present mount and holder assembly being capable of accomplishing substantially the same functions as that of the application and in a more efiicient manner from the standpoint of change-over operations as will be set forth presently.

The efiiciency of diamond-carrying mounts and holders such as have been exemplified in the above-identified co-pending application is predicated upon the fact that the diamond dressing stone is at all times oriented relative to the grinding wheel in such a manner that its 110 direction is parallel to the direction of abrasion. In using such an assembly, as well as in using the assembly of the present invention, the method outlined in said copending application is followed. Reference may be had to such application for a full disclosure of the method involved, but for purposes of description herein, it is deemed suflicient to state that a dressing edge of the stone which extends in the 110 direction of the stone according to the system of crystallographic notation known as Millers indices, and which may be the result of the presentation of an edge existing between two intersecting octahedron faces, is initially presented to the grinding wheel in the plane of rotation thereof so that the bisecting plane of the two intersecting octahedron faces extends normal to the surface of the wheel at the line of contact and parallel to the direction of abrasion. This 2,912,971 Patented Nov. 17, 1959 2 truing dressing position is maintained during an initial dressing phase during which wear takes place and new dressing edges are generated on the opposite sides of the flat which is developed on the stone as a result of the abrasion involved. When the nature of such flat becomes critical. and dressing operations are no longer practicable,

dressing operations are momentarily terminated and a new position is given the diamond by a lateral angular displacement thereof wherein one or the other of the generated edges at one side or the other of the critical flat is presented to the grinding wheel surface. This newly selected edge also extend parallel to the 110 direction of the dodecahedron plane and'its presentation to the rotating surface commences a second grinding phase wherein abrasion takes place in a plane or family of planes inclined relative to the initial 110 plane but in the 110 direction offering maximum resistance to abrasion, and wherein a second critical fiat is generated. Upon generation of such second critical fiat, dressing operations are again momentarily terminated and the previously generated edge of the critical flat in the dodecahedron plane, not selected for dressing in the second phase, is now selected for dressing purposes. To properly apply such'edge to the rotatingsurface, a second new position is given the diamond by lateral displacement thereof and the tool is restored to its initial head-on position to present the new edge existing by virtue of the intersection between the two previously generated flats to be presented squarely to the surface of the wheel. This last mentioned edge will exist in the crystal structure as a counterpart of the 110-directed line originally selected for dressing purposes in the first phase of operations, and

the diamond as a whole will assume the same relativev for dressing purposes, it' will be seen that, for commerchange-over operations involving cially practicing such a method, a dressing tool assembly is required by means of which movement of the tool shank laterally through a predetermined angle in one direction or the other about an'axis extending at a right angle to the axis of rotation of the wheel and normal to the radius of the wheel at the point of contact between the wheel periphery and the diamond must be effected. Such shifting of the tool shank, and the anchoring thereof in the selected positions of which it is capable of assuming will effect the desired presentation of the diamond to the wheel for optimum dressing conditions at the commencement of any given dressing phase. Such a dressing tool assembly forms in part the subject matter of the above-mentioned co-pending application, as well as forming the subject matter of the present invention which is designed as an improvement over the dressing too-l assembly shown in such application.

In the tool assembly of the above-mentioned application, selective anchoring of the tool shank in three predetermined positions of angularity is made possible by pivotally mounting the shank on a holder having three placement holes formed therein designed for'selective register with a single threaded reference hole formed in the tool shank. A clamping bolt is selectively receivable through the placement holes and is designed for threaded reception in a reference hole and, when the bolt is thus positioned, tightening thereof will serve to clamp the tool shank in the desired positionof orientation. While such an assembly will effectively perform its intended function, it-has been found that in actual practice the necessary unthreading of the clamping bolt, its removal from the assembly, accurate alignment of the various pairs of holes involved, replacement of the bolt and tightening thereof, involve numerous detailed operations which are troublesome to an operator and which require a modicum of skill and which are timeconsuming. Furthermore, the assembly is subject to clogging due to the accumulation of abrasive products or other foreign material in the unused holes.

The present invention is designed to overcome the above-noted limitations that are attendant upon the construction and use of tool holder assemblies of the specific type briefly outlined above, and toward this end, it contemplates the provision of an improved dressing tool assembly capable of use in carrying out the method set forth in the above-mentioned co-pending application, and wherein the tool shank is carried in a clamping block which, in turn, is pivotally carried in a holder, the shank and block being bodily movable as a unit between the desired three positions of orientation including a centered or medial position and two laterally displaced positions of angularity, a single clamping bolt being provided and erving the dual function of establishing the pivotal axis of swinging movement for the block and shank and of rigidly clamping the various parts in their selected positions of adjustment. Cooperating abutments on the holder and clamping block respectively limit the swinging movement of the block relative to the holder and determine the extreme or laterally displaced positions of the block while the medial position thereof is readily obtained by visual sighting means made possible and facilitated by the specific design of the block and holder.

The provision of a dressing tool assembly of the char acter briefly outlined above being among the principal objects of the invention, it is another object to provide such an assembly wherein the tool shank which carries the dressing tool or diamond is reversible in the clamp ng block in which it is mounted in such a manner that the diamond may selectively be applied to the grinding wheel with its 110 direction parallel to the direction of abrasion and normal to the surface of the grinding wheel as outlined above, for abrasion in opposite directions as desired so that advantage may be taken of any buttress effect which may be inherent in a given stone, thus contributing toward preservation of the lateral faces of the stone and of those faces which underlie the trailing edge of the stone during dressing operations.

Yet another object of the invention, in a dressing tool assembly of this sort, is to provide means whereby the tool holder portion of the assembly may be mounted in or attached to a slide or carriage by means of wh ch the assembly is caused to traverse the face of the grinding wheel with compensation being made for the normal drag angle associated with single point tool holders.

The provision of a dressing tool assembly which is relatively simple in its construction and which. therefore, may be manufactured at a low cost; one which is rugged and durable and which, therefore, is unlikely to get out of order despite anv rough usage to which it may be put; one which is easily assembled and dismantled for purposes of inspection, replacement or substitution of parts or repair; one which reouires no particular skill for its proper use during dressing operations; and one which otherwise is well ada ted to perform the sevices reouired of it are further desirable features which have been borne in mind in the production and development of the present invention.

Ot er obiects and adv ntages of the invention, not at this time numerated, will become more readily apparent as the following description ensues.

in the accompanving two sheets of drawings forming a part of this specification. a preferred embodiment of the invention has been shown.

In these drawings:

Fig. 1 is a fragmentary top plan view of a dressing tool assembly constructed in accordance with the principles of the present invention and showing the same operatively associated with a grinding wheel, the surface of which is to be dressed;

Fig. 2 is a side elevational view of the structure shown in Fig. 1;

Fig. 3 is a front elevational view of the structure shown in Fig. 1;

Fig. 4 is a sectional view, partly in elevation, taken substantially along the line 44 of Fig. 2;

Fig. 5 is a sectional view, partly in elevation, taken substantially along the line 55 of Fig. 2; and

Fig. 6 is a sectional view, partly in elevation, taken substantially along the line 66 of Fig. 1.

Referring now to the drawings in detail, a dressing tool assembly constructed in accordance with the principles of the present invention has been designated in its entirety at 10 and involves in its general organization a tool in the form of a shank, slug or tool 12 as it is variously termed, carrying a diamond 14 at its forward end. The shank 12 is in the form of an elongated cylindrical body, the forward end of which is tapered to provide a frusto-conical portion 16, the apex of which carries the cutting tool proper or diamond 14. The external configuration or shape of the diamond 14, especially the configuration of the forwardly exposed surface thereof, may vary within certain limits to better accommodate different installations, grinding wheels having different textures, diameters, etc., and it may vary somewhat for each particular installation. However, the arrangement of the inherent crystallographic axes in the isometric system of crystallization of the diamond relative to the iong'itudinal and transverse directions of the shank 12 are predetermined within very fine limits regardless of the nature of the work or of the particular diamond selected for dressing operations in order to effect presentation of the d amond to the work in varying angular positions according to the method involved in utilizing the dressing tool assembly 10 when the shank is adjusted to any of the positions of which it is capable of assuming.

The shank 12 is remova lv carried in a clamping block 18 of generally trapezoidal configuration in plan view and having fiat top and bottom faces 20 and 22, respectively, front and rear faces 24 and 26. respectively, inclined side surfaces 28 and 30, respectively. and parallel side surfaces 32 and 34, respectively. The clamping block 18 is formed with a longitudinally extending cylindrical bore 36 therethrough in which bore t e shank 12 is adapted to be removably and telescopically received in either of two positions of orientation in a manner and for a purpose that will be made clear presently. Accordingly, the block 18 is split transversely on a horizontal plane as indicated at 38 and a clamping bolt 41) is provided for drawing the upper and lower sections 42 and 44, respectively, on the upper and lower sides of the split 38 toward each other to firmly clamp the rear end region of the shank 18 within the split bore 36 after it has been received therein in the desired position of orientat on, as well as for securely clamping the entire tool shank and clamping block assembly 12, 18 in selected positions of orientation within a one-piece holder which has been desi nated in its entirety at 46.

The holder 46 includes a cylindrical s em or shank portion 48 designed for attachment to a slide or carriage (not shown) by means of which the dressing tool assembly 10 as a whole s traversed across the face of the grinding wheel. It will be understood, of course, that in certain installations, the tool assembly 19 will be maintained stationary and the rotating grind n wheel will traverse the tool. Irrespective, however, of the part cular means whereby the tool and grinding wheel are caused to move laterally relative to one another, the essential features of the invention are at all times preserved.

The forward end of the stem portion 48 is provided with a yoke-like clamping head or yoke 50 which is generally of U-shape in vertical cross section and which includes upper and lower clamping portions or arms 52 and 54, respectively, and a connecting base portion 56. The inner face 58 of the base portion 56 extends vertically while the outer face 60 thereof is displaced at an angle of approximately 15 from a vertical plane and the axis of the shank portion 48' extends normal to the face 60 and is provided with the usual flat 62 which is designed for cooperation with a suitable set screw (not shown) or other clamping means associated with the traversing carriage or slide. The inside faces of the arms 52 and 54 provide a pair of clamping surfaces 64 and 66, respectively, between which the upper and lower faces 20 and 22 of the clamping block 13 are adapted to be frictionally gripped in a manner that will be set forth subsequently when the clamping bolt 40 is tightened.

As best seen in Figs. 4 and 6, the upper clamping arm 52 is formed with an opening 70 therethrough, in which opening there is received the shank portion 72 of a bushing 74 having an enlarged head 76 which seats against the outer face of the arm 52. The shank portion 72 projects completely through the opening 70 and extends into an opening 78 provided in the upper section 42 of the split clamping block 18. The lower arm 54 is provided with an opening 80 therethrough, in which opening there is received the shank portion 82 of a bushing 84 having a head portion 86 which seats on the underneath face 22 of the arm 54. The shank portion 82 projects completely through the opening 80 and extends into an opening 88 provided in the lower section 44 of the split clamping block 18. The two openings 78' and 88 constitute, in elfect, a transverse bore which intersects the longitudinally extending split bore 36.

From the above description, it will be seen that when the two bushings 74 and 84 are in position within their respective openings 70 and 80, the clamping block 18 is pivotally mounted for swinging movement within the space or slot 90 existing between the opposed inner faces of the two arms 52 and 54. The transverse thickness of the clamping block 18 is such that the block may be received within the slot 90 afforded by the arms 52 and 54 with little or no side play, while at the same time the block is freely movable between the two arms so that it may be swung between two extreme positions as will be described presently. The bushing 74 is provided with a smooth bore 92 while the bushing 84 is provided with a threaded bore 94. The diamond-carrying shank 12 is formed with a diametrically extending bore 96 which is designed for registry with the openings 78 and 80 in the upper and lower sections 42 and 44, respectively, of the split clamping block 18 and with the bores 92 and 94 in the bushings 74 and 84, respectively, when the diamondcarrying shank 12 is assembled in the dressing tool assembly 10.

The clamping bolt 40 is provided with an elongated shank 100 which extends through the bore 92 in the bushing 74, the bore 96 in the shank 12 and has its lower threaded end 102 threadedly received in the bore 94 of the bushing 84. The clamping bolt 40 is provided with an enlarged head 104 having a socket 105 formed therein designed to receive a suitable tool, such as an Allen wrench or the like (not shown), and adapted to seat upon the upper face of the bushing 74 when the bolt is tightened in the assembly. Upon such tightening of the bolt'40, the two arms 52 and 54 of the head portion 50 of the holder 46 are drawn together, thus in turn drawing the sections 42 and 44 of the split clamping block 18 together and causing the same to firmly clamp the diamondcarrying shank 12 therebetween to take up any looseness normally existing between the parts 12 and 18, as well as causing the clamping block 18 to be itself firmly clamped in any position of adjustment of the block within the slot 90.

Referring now to Fig. I, it will be seen that the inside 6 face 106 of the base portion 56 of the U-shaped head 50 serves to limit the extent of the swinging movement within the slot of which the clamping block 18 is capable. When the block 18 is turned about the axis of the clamping bolt 40 in a clockwise direction as viewed in Fig. 1 to the full extent of its swinging movement, the linear edge 108 at the intersection between the faces 26 and 34 of the block 18 will engage the face 106. Similarly, when the block 18 is turned about the axis of the bolt 40 in a counterclockwise direction to its fullest extent, the linear edge 11% at the intersection between the faces 26 and 34 will engage the face 106.

Still referring to Fig. 1, in the full line position of the clamping block 18, the longitudinal axis of the diamond-carrying shank 12 is in alignment with the vertical plane of the stern portion 48 of the holder 46 and, the shank 12. is bodily displaceable with the block 18 in either direction through equal angles, either to the right or to the left as shown in dotted and broken lines, respectively. These equal angles of displacement have been designated at 0 and 0', respectively, and they may assume different magnitudes within operable limits to vary the angles of displacement of the tool shank from its centered position within the holder to thus change the position of the diamond 14. In the illustrated embodiment of the invention, the angles 0 and 0 are each of 18 magnitude since this magnitude has been found to be ap propriate for most dressing operations utilizing diamonds having average shape characteristics. It has been found, however, that the holder 46 and clamping block 18 may be designed for displacements of from 6 to 30 in either direction in the performance of special grinding operations or to accommodate stones having specific shapes.

It is deemed unnecessary herein to set forth in detail the method involved in the dressing of grinding wheels such as that shown in Fig. 1 at W since this method is substantially identical with the method described in the above-mentioned co -pending application. Briefly, however, such method involves three repetitious phases of dressing operations, each phase utilizing application of the diamond 14 to the surface of the grinding wheel W in a different position of orientation. These positions are first, the centered position which the diamond assumes when the diamond-carrying shank 12 is in coincidence with the vertical plane of the stem 48; secondly, the laterally displaced position of the diamond when the edge 108 engages the face 106; and thirdly, the displaced position of the diamond when the edge 111) engages the face 186.

In the use of the assembly 10, when it is desired to position the diamond in its full line centered position, the clamping bolt 41) may be loosened and the clamping block 18 moved to its medial position with this position being ascertained by the judgment of the operator. Accurate positioning of the diamond within exceedingly fine limits of tolerance is facilitated by the optical effect produced by the exposed portions of the upper face 2% of the clamping block 18 on opposite sides of the upper arm 52 of the holder head 50. Movement of the block 18 in one direction or the other away from its centered position will serve to increase one visible exposed area of the face 21 and to decrease the other visible exposed area of the face so that the area differential between the two exposed portions changes appreciably with slight displacements of the block 18. Since at normal distances from the eye, both areas are within the occluded area of vision, an operator, by judging discrepancies in area, is able to bring the block 18 to a centered position within very fine limits. After the initial centered position of the block 18 has been thus attained, the clamping screw 48 is tightened and dressing operations may be commenced.

When it is desired to shift the position of the block 18 to bring the diamond 14 to either of its laterally offset or displaced positions, it is merely necessary to loosen the clamping screw 40 and flip the block (so to speak) manually to the desired extreme position wherein one or the other of the two linear edges 18% or 119 engages the face we, as previously described, after which the clamping screw 40 may again be tightened.

The bushings 74 and 84 are removably secured within their respective openings 70 and 80 by a soldering operation so that, in effect, they constitute fixed integral portions of the holder 18 and so that they may, if desired, be unsoldered by a heating operation and i: v. the assembly 10. In most instances, it wil expedient to present the head 104 of the clamping bolt 40 upwardly so that it is readily accessible for manipulament shown in the accompanying drawing or described in this specification as various changes in the details or construction may be resorted to without departing from the spirit of the invention. Only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. A tool and tool holder assembly designed for use in dressing a surface on a rotating grinding wheel or the like, said assembly comprising a tool shank in the form of an elongated metal member carrying a diamond dressing eiement at its extreme forward end, a clamping block for said holder having fiat parallel upper and lower surfaces, said clamping block being formed with a longitudinal split bore into which the rear end region of the shank extends with the forward end region of the shank projecting forwardly beyond the confines of the block, said block also being formed with a transverse bore intersecting said split bore, a holder for pivotally supporting said block, comprising a clamping yoke having spaced parallel upper and lower clamping arms respectively, and a connecting base portion, said arms being formed with a pair of aligned transverse openings therethrough, said block being interposed between said parallel arms with said transverse openings in register with said transverse bore, a clamping bolt extending into said aligned openings and passing through said transverse and split bores and having associated therewith means for drawing said parallel arms together to bring the inner faces thereof into clamping engagement with said upper and 10K 'er faces of the clamping block to, in turn, deform the block and move the opposite sides of said split bore into clamping engagement with said shank, and interengaging limit stop means on said holder and block for limiting the extent of swinging movement of the block relative to the holder in either direction.

2. A tool and tool holder assembly as set forth in claim 1 wherein said interengaging limit stop means comprises first and second pairs of cooperating abutments on said base portion of the holder and clamping block, respectively.

3. A tool and tool holder assembly as set forth in claim 1 wherein the opening in said lower clamping arm is threaded and wherein said clamping bolt has its distal end threadedly received in said threaded opening.

4. A tool and tool holder assembly as set forth in claim 1 wherein said shank is formed with a transverse bore therethrough extending at a right angle to the axisof the shank and wherein sail clamping bolt projects completely through said latter bore whereby said shank may be selectively assembled in said clamping block in upright and inverted positions wherein the 110 crystallographic axis of the diamond dressing element is turned end-to-end.

5. A tool and tool holder assembly as set forth in claim 1 including, additionally, an attachment stem projecting rearwardly from said interconnecting base portion of said holder at an acute angle from the longitudinal axis of said shank and in the vertical plane passing through said axis.

6. A tool and tool holder assembly designed for use in dressing a surface on a rotating grinding wheel or the like, said assembly comprising a tool shank in the form of an elongated metal member carrying a diamond dressing element at its extreme forward end, said diamond dressing element being fixedly secured in said member with its direction, according to Millers system of crystallographic notation, extending at approximately a right angle to the longitudinal axis of the shank, a clamping block for said holder having flat parallel upper and lower surfaces, said clamping block being formed with a longitudinal split bore into which the rear end region of the shank extends with the forward end region of the shank projecting forwardly beyond the confines of the block, said block also being formed with a transverse bore intersecting said split bore, a holder for said block, comprising a clamping yoke having spaced parallel upper and lower clamping arms respectively, and a connecting base portion, said arms being formed with a pair of aligned transverse openings therethrough, said block being interposed between said parallel arms with said transverse openings in register with said transverse bore,'a bushing disposed in each of said openings and including shank portions which project inwardly beyond the confines of the openings and extend into said transverse bore whereby said block is pivotally mounted on said bushings within said yoke, a clamping bolt extending into said bushings and passing through said transverse and split bores and having associated there with means for drawing said parallel arms together to bring the inner faces thereof into clamping engagement with said upper and lower faces of the clamping block to, in turn, deform the block and move the opposite sides of said split bore into clamping engagement with said shank, and interengaging limit stop means on said holder and block for limiting the extent of swinging movement of the block relative to the holder in either direction.

7. A tool and tool holder assembly as set forth in claim 6 wherein said tool shank is cylindrical in configuration and is provided with a diametrically extending bore therein, said clamping bolt extending through said latter bore.

8. A tool and tool holder assembly as set forth in claim 6 wherein one of said bushings is threaded interiorly and wherein said clamping bolt has its distal end threadedly received within said interiorly threaded bushmg.

9. A tool and tool holder assembly as set forth in claim 6 wherein each of said bushings are formed with enlarged heads overlying the outer rim of one of said openings, one of said bushings being interiorly threaded, the distal end of said clamping bolt being threadedly received within said interiorly threaded bushing, and an enlarged head on said clamping bolt overlying the enlarged head of the other bushing.

10. A tool and tool holder assembly as set forth in claim 9 including, additionally, a quantity of solder fixedly securing each of said bushings in its respective opening, said bushings being interchangeable in said openings whereby upon heating of the metal in the vicinity of said bushings, the solder may be melted to release said bushings from said openings for purposes of interchanging the same.

11. A tool and tool holder assembly designed for use in dressing a surface on a rotating grinding wheel or the like, said assembly comprising a horizontal tool shank in the form of an elongated metal member fixedly carrying a diamond dressing element at its. extreme forward end, a horizontal clamping device for said shank, said clamping device being divided horizontally and longitudinally to provide substantially parallel arms between I which the rear end region of the shank extends with the forward end region of the shank projecting forwardly beyond the confines of the device, said parallel arms being formed with aligned transverse bores intersecting the divided region of the device, a holder for pivotally sup porting said device and comprising a clamping yoke having spaced parallel upper and lower clamping arms respectively, and a connecting base portion between certain opposed ends of the clamping arms, said clamping arms being formed with a pair of aligned transverse openings there through, said device being interposed between said clamping arms with said transverse bores in register with said transverse openings, a vertical clamping bolt extending into said aligned openings and passing through said transverse bores and across the divided region of the device and having means associated therewith for drawing said clamping arms together to bring the inner faces thereof shank, and interengaging limit stop means on said holder and device for limiting the extent of swinging movement of the device with respect to the holder in either direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,505,322 Desmon Aug. 19, 1924 2,292,957 Meeson Aug. 11, 1942 2,302,921 Spencer Nov. 24, 1942 2,395,662 Hoagberg Feb. 26, 1946 FOREIGN PATENTS 546,401 Great Britain July 10, 1942.

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