US3378000A - Wheel dresser - Google Patents

Description

F. M. DAY

April 16, 1968 WHEEL DRESSER Filed Jan. 11, 1965 F/G.4 FIG. 5

INVENTOR. FLORY M. DAY %5 HM; L

United States Patent Ofifice 3,378,999 Patented Apr. 16, 1968 3,373,099 WHEEL DRESSER Flory M. Day, 43%3 W. 219th St., Fair-view Park, Ghio 44126 Filed 11, 1965, Ser. No. 424,695 5 Claims. (Cl. 125-11) ABSTRACT OF THE DISCLOSURE A form-dressing tool having diamonds set in a matrix so as to present cutting surfaces which are exposed at both the face and the sides of the matrix.

This invention relates generally to the art of wheel dressing, and more specifically to new and useful improvements in form-dressing tools for abrasive grinding wheels and the like.

The invention is particularly concerned with improvements in the construction of diamond dressing tools of the type described in US. Patent No. 2,897,810, issued Aug. 4, 1959, to Flory M. DAmato. As disclosed in that patent, the tool is comprised of two spaced dressing sections which are carried in tandem relationship by a suitable spanner and adapted simultaneously to engage the wheel in a common surface path. The tandem construction is such that the leading tool section does the bulk of dressing work, while the second section acts as a filter to correct any errors left by the leading section.

Among the several important advantages resulting from use of the tandem dressing tool are a greatly improved wheel life and a superior wheel finish. It is possible with the tool to achieve a rough and a finished dressing operation at one time, thereby reducing the number of dressing passes across the wheel. The tool also has the ability to close the wheel grain for fine workpiece grinding, as well as to open the grain for fast cutting. Another important feature is that the tool makes it possible to overcome any inaccuracy in tool positioning due to wear or improper provisions in the tool holder, as well as to assure the correct approach angle regardless of the adjusted setting of the tool.

A purpose of the present invention is to provide a new tandem dressing tool which possesses all of the advantages described above and, in addition, is uniquely adapted to dress wheels used in form grinding operations.

Form grinding has been performed for many years and several diiterent form-dressing techniques and tools have been evolved to give the wheels the shape of the workpiece profile. Nearly all of these conventional techniques and tools have had certain disadvantages which have made form-dressing a difficult and exacting operation. In most cases, it is desirable to use a diamond in order to produce the desired finish and to speed up the dressing process by cutting the abrasive of the wheel at high speeds of rotation. However, with the conventional forming devices, it has been difficult to present the diamond normal to the active wheel surfaces and to maintain the diamond so that the shape of the wheel could be closely and accurately controlled. it was frequently found that errors in shape resulted from variations in the diamond contour produced by uneven wear of the diamonds and/or by an incorrect approach angle of the tool with the wheel.

The new diamond dressing tool provided by this invention is capable of form-dressing grinding wheels with greatly improved shape control. With the new tool, it is possible to dress a wheel so it is capable of simultaneously form grinding multiple workpiece surfaces which heretofore could be ground only with different wheels or in several stages. It is also possible in many instances accurately to shape the active surfaces of a wheel so that it can grind complex and irregular workpiece profiles that could not be form ground at all in the past. The invention is further characterized by a construction which obtains even diamond wear so as further to improve the accuracy and speed of the dressing operation and to extend the dressing tool and wheel life.

In the preferred embodiment which is contemplated, the tool comprises two diamond dressing sections connected in tandem relation so that the diamonds of both sections are active on the same rotating surface of the wheel. The two sections are connected so as to assure the proper angle of approach to the wheel at all times. The diamonds in one or both of the tool sections are arranged so that they are capable of cutting the wheel on multiple diameters. With this arrangement, the dressing operation can be accomplished in a minimum amount of time and complex configurations of the wheel surfaces can be generated. Moreover, even diamond wear and a superior and accurate dressing of the wheel surfaces are obtained.

Other features and advantages of the invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawing.

In the drawing:

FIGURE 1 is a side elevational view, partially in crosssection of the preferred embodiment of the invention;

FIGURE 2 is another side elevational view showing the preferred embodiment as applied to the surface of a grinding wheel;

FIGURE 3 is a crosssectional view taken on the line 33 of FIG. 2;

FIGURE 4 is an end elevational view of one of the preferred diamond dressing sections; and,

FIGURE 5 is an end elevational view of a modified diamond dressing section.

Referring now to the drawing, the preferred construction contemplated by this invention is generally designated by reference numeral iii. The tool comprises a substantially C-shaped s anner member 11 having end portions 12, 13 and a rigid interconnecting body portion 14-. While a substantially C-shaped spanner is preferred, it is to be understood that the invention is not limited to the size or shapeof possible spanners capable of functioning in the same manner.

The preferred embodiment is constructed to provide a tandem dressing action in which two tool dressing sections are simultaneously applied in planes normal to the axis of the Wheel with each tool dressing the same surface path of the rotat ng wheel. T 0 this end, the tool is illustrated as including two dressing sections 15, 1% which are carried at the ends 12, 13, respectively, of the spanner 11. The dressing section 15 and preferably the section 16 include a plurality of diamonds which are arranged to cut the wheel in a manner to be more fully described.

A carriage adapter 26 is provided to carry the spanner 11. The carriage adapter 29 ha a stem portion 21 which is insertable into the bore of a conventional tool holder, a portion of which is diagrammatically illustrated at 22. The stem portion 21 of the adapter Ell has a fiat surface 23 and is adjustably secured within the bore of the tool holder 22 by means of a set screw 24 which engages the surface 23. it will be understood that the tool holders are part of the grinding machine and have various forms. All of them, however, provide for movement toward and away from the wheel and also for movement laterally across the active wheel surfaces.

With conventional single point tools, inaccuracies in the work, as well as uneven diamond wear, sometimes resulted from improper positioning of the dressing tools due to wear or improper provisions in the tool holder which do not provide for a correct tool approach angle. Such inaccuracies are overcome with the illustrated construction through the provision of the tandem tool sections 15, 16 and the manner in which the spanner is connected to the carriage adapter 20. As shown, the body 30 of the adapter 20 is in the form of a yoke having arms 31, 32. The body portion 14 of the spanner 11 is mounted between the yoke arms 31, 32 and is provided with a hole 33 intermediate the ends 12, 13 of the spanner. The hole 33 is aligned with holes formed in the yoke arms 31, 32 and a socket cap screw 34 is mounted through the holes and is threaded into the yoke arm 32, as shown most clearly in FIG. 3.

In the preferred manner of use, the carriage adapter 20 is set in a vertical position and the stem portion 21 of the adapter is locked in the holder 22 by means of the set screw 24. With the spanner 11 loosely supported between the yoke arms 31, 32, dual contact is made between the surface of the grinding wheel 35 and the tool dressing sections 15, 16. This is done by bringing the wheel into contact with the dressing sections or by bringing the tool into contact with the wheel, as is the case with centerless grinders. The positioning operation is carried out with the wheel 35 stationary. When the two diamond sections are properly positioned in contact with the wheel, the spanner 11 is locked tightly in position between the yoke arms 31, 32 by tightening the socket cap screw 34. The tool is thereafter properly positioned to form-dress the wheel 35 to a complete finished condition without further adjustment or changing. After securely locking the spanner 11, the tool 10 and the wheel 35 are separated so that the grinding machine can be started and then the dressing operation is performed.

A principal aspect of the present invention resides in the formation of the tandem diamond dressing sections 15, v16. These tool sections are identical and are constructed so that it is possible to generate complex wheel surface configurations and accurately control the shape. According to the preferred construction most clearly shown in FIG. 4, the active face of each diamond dressing section is provided with a plurality of diamond cutting members 40 which are mounted in the opposite sides of a suitable matrix 41. The matrix 41 has a flat end face extending from one side face to the other and may be formed of a standard material, including powdered metals such as copper or tungsten carbide or the like.

The diamond dressing sections of the tool provided by this invention are uniquely characterized by the formation and positioning of the diamonds. A illustrated in FIGS. 1, 2 and 4, the individual diamonds 40 are aligned transversely of the matrix 41 and have their end and side faces flush with the surfaces of the matrix. After mounting the diamonds in the matrix, the sides of all of the diamonds at corresponding sides of both sections 15, 16 are carefully group lapped so as to be fiat, parallel and in alignment. The end faces of the diamonds are also lapped so that they are at 90 degrees to the side faces and so that all of the end faces can be applied to the Work in a common surface path of rotation.

With the foregoing construction, it is possible to formdress the active surfaces of the wheel 35 on multiple diameters. It will be seen that the diamonds are adapted to cut perfect square corners by simple straight line movements of the tool holder 22. By moving the tool holder with cams or forms of the same shape as the work, as is conventional in the industry, it is also possible to generate radii between adjacent surfaces and other desired surface configurations. At the same time, the tandem relation of the tool sections 15, 16 is such that the diamonds can always be presented normal to the wheel surfaces, thus assuring accurate shape control.

FIGURE illustrates a modified tool section 45 in which the diamond cutting members are in the form of thin strips 46 extending across the matrix 47 between its sides. It will be seen that diamond strips 46 present a substantially greater area at the active faces of the tool sections than do the individual diamonds 40 in the embodiment of FIGS. l-4. Due to the greater cutting area, it has been found that there is a tendency for excessive heat to be generated during the grinding operations and that this excessive heat can result in cracked diamonds and/ or over-heated ground parts. In order to prevent the generation of excessive heat, it is preferred to form the strips 46 so that they have a width on the order of of an inch or less. The action of the diamond strips 46 in form-dressing the wheel 35 and generating complex configurations is the same as described above in conjunction with FIGS. 14.

In both embodiments of the invention, the arrangement of the diamonds is such as to provide for uniform diamond wear due to their positioning in the matrix and the manner of presenting the diamonds to the wheel. The positioning of the diamonds is characterized in that they are set flush with the sides of the matrix and are carefully lapped so that diamonds in both tool sections have their sides flat, parallel and in alignment. The end faces of the diamonds are also preferably flush with the matrix and are lapped at degrees to their sides.

Many other modifications and variations of the invention will be apparent to those skilled in the art in the light of the foregoing detailed description. Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than as specifically shown and described.

What is claimed is:

1. In a device for dressing the abrasive wheel of a grinding machine so that it is adapted accurately to form grind multiple workpiece surfaces in a single operation, said wheel being rotatable in a plane about a centerline axis and the machine including a tool holder which is movable toward and away from the active surfaces of the wheel and in a direction across said active surfaces parallel to said axis, the improvement comprising tool holder adapter means engageable by the *tool holder of the grinding machine and movable therewith, a tool member held by said adapter means in a selected position to assure approach of said tool member with respect to the active surfaces of said wheel at a proper cutting angle, and a cutting section secured to said tool member in position to be presented to the wheel by movement of the tool holder, said cutting section including a matrix having side faces and an end face extending from one side face to the other side face, said end face being adapted to be presented to the wheel, and a plurality of diamond cutting members in said matrix, said cutting members presenting exposed side and end cutting surfaces which merge at the edges of said matrix defined by said side and end faces, said cutting members comprising spaced strips extending transversely of said matrix between said side faces, and said strips having a maximum width of about of an inch.

2. A form-dressing tool for an abrasive wheel comprising:

(a) a spanner member having first and second extrernities,

(b) a wheel dressing tool section carried by said spanner at each extremity,

(c) each of said tool sections including a matrix having opposite side faces and a flat end face extending from one side face to the other, a plurality of individual diamonds mounted in said matrix, said diamonds being spaced along the edges of said matrix defined by said end and side faces and being aligned transversely of said end face, each of said diamonds having exposed side and end cutting surfaces flush with said side and end faces of said matrix, said side cutting surfaces along corresponding side faces of said matrixes of both tool sections being fiat, parallel and in alignment, and said end cutting surfaces being square With said side cutting surfaces,

(d) a tool holder adapter, and

(e) means connecting said spanner to said adapter.

3. A form-dressing tool for an abrasive wheel comprising:

(a) a spanner member having first and second extremities,

(b) a wheel dressing tool section carried by said spanner at each extremity,

(c) each of said tool sections including a matrix having side and end faces and a plurality of cutting members in the form of thin diamond strips extending across said end face of the matrix between its side faces, said strips having a maximum width of about of an inch and having cutting surfaces flush with said side and end faces of said matrix, said cutting surfaces along corresponding side faces of said matrixes of both tool sections being flat, parallel in alignment, and said cutting surfaces at said end faces being square with the cutting surfaces as said side faces,

(d) a tool holder adapter, and

(e) means connecting said spanner to said adapter.

4. In a grinding machine having an abrasive wheel and a tool holder adapted to carry a dressing tool to and from the wheel and to move the tool laterally with respect to the wheel, an improved dressing tool comprising:

(a) a substantially C-shaped spanner member having spaced end extremities,

(b) an adapter member engageable by the tool holder,

(c) means securing said spanner to said adapter so that said spanner can be adjusted in the plane of wheel rotation, and

(d) tool sections carried by said spanner member at each of said extremities,

(e) each of said tool sections including:

(i) a matrix having side and end faces, and (ii) a plurality of diamond cutting members in said matrix, said cutting members being in the form of thin diamond strips extending across said end face of said matrix between its side faces and having a maximum width of about of an inch, said strips having exposed cutting surfaces transversely aligned along the sides of said matrix, whereby said tool sections can out said abrasive wheel on multiple diameters, said cutting surfaces being flush with the sides of said matrix and said cutting surfaces along each side being flat, parallel and in alignment.

5. A device for dressing a abrasive wheel of a grinding machine so that it can form grind multiple workpieces in a single operation, said device comprising a tool member, a cutting section including a matrix carried by said member in position to be presented to the active surfaces of a grinding wheel, said matrix having opposite side faces and a flat end face extending from one side face to the other, a plurality of individual diamonds set in said matrix, said diamonds being spaced along the edges of said matrix defined by said end and side faces and being aligned transversely of said end face, and each of said diamonds having exposed end and side cutting surfaces flush with said faces of said matrix, said side cutting surfaces being fiat, parallel and in alignment along said side faces and said end surfaces being square with said side surfaces.

References Cited UNITED STATES PATENTS 419,193 1/1890 Foerster. 1,488,912 4/ 1924 Foerster. 1,939,991 12/1933 Krusell. 2,443,370 6/1953 Bakker 125-39 2,730,848 1/1956 Wallace 125-39 X 2,860,623 11/1958 Meunch 12539 2,897,810 8/1959 DAmato 12511 HAROLD D. WHITEHEAD, Primary Examiner.

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