US2585990A - Method of grinding intricate contours - Google Patents

Description

w. G. BALDENHOFER 2,585,990

METHOD OF GRINDING INTRIC'ATE CONTOURS Feb. I9, 1952 3 Sheets-Sheet 1 Filed Sept. 8, 1947 IL l|||s INVENTOR WILLIAM G. BALDENHOFER f ATTORNEYS Feb. 19, 1952 w. G. BALDENHOFER 2,585,990

METHOD OF GRINDING INTRICATE CONTOURS Filed'Sept. a, 1947 5 Sheets-Sheet 5 la- 5 STEP 1 Foam ROLL BY TOOL or 5mm:

TO BE STEP 3 GBIND FORM T00!- BY WHEEL SMPED IN STEP 2 Fawn z" mu. BY ram. mu:

STEP 5 CRUSH F'DiM/l 2 WHEEL m STEP 5 TO a 12m. memo woven Mnosm u: PIECES i- INVENTOR mm. LIAM e .BALDENHOFER av ATTORNEYS Patented Feb. 19, 1952 METHOD OF GRINDING INTRICATE CONTOUBS William .G. Baldenhofer, Springfield, Ohio, as-

signor to The Thompson .Grinder Company, Springfield, Ohio, a corporation of Ohio Application September 8, 1947, Serial No. 7 72,605

Claims.

This invention relates to grinding machines, and particularly to methods and apparatus employed in connection with grinding machines for producing intricate contours.

In the forming of intricate contours, as for example, form tools for certain types of turning work, the most practical procedure is to shape these members by a grinding process. Examples of tools of this type will be found in the art of manufacturing crankshafts and other automotive workpieces.

Tools of this type are usually required in great number and must be maintained in high production and, accordingly, tools :for such parts must likewise be produced in quantity. Thus, it is customary for the manufacturers to carry a rather heavy inventory of forming tools of this type in order to prevent any curtailment of the production of the workpieces beingformed thereby.

It is customary in forming tools of this type to produce them by grinding, and generally by truing a grinding wheel to the shape of a small portion of'the form and producing the entire tool by a series of grinding operations with frequent reshaping of the grinding wheel and relative movement between the tool and wheel. The entire contour of the tool is thus reproduced thereon.

This method of producing form tools, especially those which are intricately shaped, is slow and expensive. Furthermore, due to the fact that only a small part of the tool is :ground at a time, the accuracy of the finished tool is often not as great as desirable.

Tools of this nature can be formed to highly accurate dimensions and with reasonable rapidity by using a grinding wheel having a width at least equal to the surface of the tool to be ground, and shaping the periphery of the wheel to be complelmentary to the configuration of the form tool being operated thereby.

This method of producing the tools is rapid and relatively inexpensive and produces workpieces accurate within close limits. The best method of shaping a wheel for an operation of this type is by crush forming with a roll. However, the forming of a wheel requires the use of an accurately shaped roll having a cross-sectiona1 configuration equivalent to that of the "workpiece which is to be formed. Heretofore it has been necessary to form the rolls for dressing the grinding wheel to the proper shape by slow and expensive processes similar to the process mentioned above in connection with former processes for producing the finished form tools.

The particular object of the present invention is to provide an improved method whereby form tools of intricate contours can be inexpensively and rapidly produced by a process utilizing the technique of crush forming .a grinding wheel,

It is a further object of this invention to provide a method of reproducing form tools and the like having intricate contours whereby the said tool or article can be made or duplicated from an existing tool having the same configuration.

It is a further object to provide an improved apparatus for grinding workpieces to intricate contours and utilizing crush forming of the grinding wheel.

It is also an object to provide an apparatus for forming grinding wheels to intricate configurations and including means for generating intricate contours on crushing rolls to be employed in the shaping of the grinding wheel.

These and other objects and advantages will become more apparent upon reference to the following description taken in connection withthe accompanying drawings in which:

Figure l is a perspective view showing a typical grinding machine having a dressing and roll forming apparatus according to this invention mounted-on the table thereof, and adapted for practicing the methods of this invention;

'Figurez is a somewhat enlarged View of a part of the machine looking from the operators side thereof;

Figure 3 is an enlarged transverse section indicated by the line 3.3 on Figure 2 and showing details in connection with the driving and supporting .of the dressing roll;

Figure 4 is a fragmentary view showing an adjustment for adjusting the elevation of the dressing roll relative to the grinding wheel; and

Figures 5 through 10 are views of successive steps in a dressing and grinding cycle according to this invention.

Referring to the drawings, Figure 1 illustrates a grinding machine having a table 10 which is adapted for supporting workpieces to be ground as at I2. The machine also incluudes a column I4 which reciprocably mounts a saddle l6 that carries the wheel head l8. A grinding wheel at 20 is journaled in the wheel head l8 and is driven by any suitable motor means. Also mounted on the table 10 of the machine is the dressing and roll forming fixture of this invention as at 22.

Referring to Fi res 2 and 3 it w l be Seen th the fixture 22 comprises a first bed part 24 which is rigidly secured to the table Ill and which inecludes an upstanding part at one end as at 26 which provides a transverse pivot shaft 28. Supported on the .pivot shaft 28 is a second bed memher as at 30 which extendsalong and substantially parallel with the bed It]. The left end of the upper bed member 30, as viewed in Figure 2, is supported on a shaft 32 which is JOurnaled ina pair of upstanding flanges 34 at the left end of the stationary or a sub-bed 24.

Relative angular adjustments between the beds is accomplished by th w e ap 51 9 36 which is mounted on the underneath side of the upper bed 36, and guided thereon as by the key 38 and which is positioned between the bottom of the bed 36 and the shaft 32. Preferably, the shoe 36 includes the wear plates 46 which engage the shaft 32.

Adjustment of the shoe 36 longitudinally of the bed 36 in order to vary the relative angularity of the beds and thereby to adjust the elevation of the dressing roll carried by the upper bed is accomplished by means of the screw 42 which engages the shoe 36 and which is mounted in the end of the bed 36 as shown in Figure 4.

It will be evident that the screw can be rotated relative to the bed but is held against axial movement therein by means of the collar 44. Means may be provided for determining the amount of adjustment given the bed 36 by placing suitable indicia on the collar 46 attached to the screw 42 if so desired.

In order to insure that the bed 36 will move exactly vertically relative to the bed 24, one of the beds may be provided with machined flats or.

pads as at 48 which bear against flat keys as at 56 provided on the other of the said beds. This arrangement prevents any lateral movement of the end of the bed 30 remote from the pivot shaft 28.

Mounted on the upper surface of the bed 36 on the left end thereof is a shaft 56 which is adapted for mounting the dressing roll 56 which is locked against rotation on the shaft as by a key 66 and which is held against axial movement relative to the shaft by the sleeve 62 which abuts the enlarged portion 64 of the shaft on one side of the said roll and by the sleeve 66 which is abutted by the nut 68 threaded to the shaft on the other side of the said roll.

The ends of the shaft 56 are suitably supported in the bearing boxes 16 and I2 on anti-friction bearings II and 13 according to individual preference.

The shaft 56 is adapted for being selectively driven or being rotatable idly in its said supporting bearings, by means of an arrangement shown at the left end of the said shaft in Figure 3. This arrangement comprises a worm wheel 14 mounted on a member 16 that is journaled on the shaft 56 as by the roller bearings I8. The worm wheel I4 and member 16 are retained in position by a washer 86 at one side thereof, and by a collar 82 and snap ring 84 at the other side thereof. The member I6 includes clutch teeth as indicated at 86 which are engageable with corresponding teeth on a clutch member 86 slidably carried at the extreme left end of the shaft 56. The member 88 is keyed to the shaft by the keying means indicated at 96 in Figure 3 and is selectively movable into or out of engagement with the clutch member 16 by means of the drawbar 92 extending completely through the shaft 56 and terminating in the knurled knob 64. This arrangement permits the knurled knob 94 to be placed at the operator's side of the dressing fixture while the more bulky drive and clutch mechanism is positioned at the back of the fixture.

The'worm wheel I4 meshes with a worm gear 96 carried on a shaft 68 that extends toward the pivot end of the bed 36 to be drivingly engaged by the output shaft of a geared head motor I66.

According to this invention means are provided for shaping rolls mounted on the shaft 56 and this is preferably accomplished by a fixture I62 adapted for mounting the forming tool I64 and being movable toward and away from the axis of the said roller by its mounting on a bed member I66. A screw I68 is preferably provided which may be rotated for positioning the fixture I62. Graduations may be provided at I I6 on the shaft I68 for determining the exact positioning of the fixture I62 if desired.

According to the process of reproducing intricatecontours as proposed by this invention, a form tool is placed in the fixture I62 and a dressing roll is shaped thereby by bringing the tool into position to bear against the periphery of the said roll and then by driving the shaft 56 through engagement of the clutch members I6 and 88. At this time the tool acts as a shaving member and shaves material from the periphery of the roll until its shape exactly conforms to that of the forming tool.

In most instances when it is desired to reproduce a contour, there will be a previously made form tool available. While such a tool may be worn to the point where it is not suitable for production processes it will nevertheless be adequate for shaving a roll to shape for the purposes of the present invention. Also, the shape which the roll will be formed to will be accurate since the shape of a form tool is generally the same through its thickness.

The steps mentioned above are shown in Figure 5 of the drawings wherein a roll H2 is being shaped by a form tool II4 which may be a tool taken from a production machine. The tool H4 is clamped in the fixture I62 and urged against the periphery of the roll II2 while the roll is driven by the shaft 56.

After the roll II2 has been formed to the proper shape, it is utilized for crushing a grinding wheel II6 to shape as shown in Figure 6. It will be apparent that the outline of the grinding wheel is the same as the outline of the formtool II4.

After the wheel II 6 has been formed by the roll II2 it is utilized for grinding one or more tools IIB to shape as shown in Figure 7. These tools are preferably mounted as the workpieces are mounted at I2 in Figure l. The tools II8 are form tools of the standard type, or are particularly shaped to be employed as shaving members.

After the tools II8 have been ground to shape, one thereof is then mounted in the fixture I62 as shown in Figure 8 and is employed for shaving another crushing roll I26 to shape. The crushing roll I26 is mounted on shaft 56 and is driven thereby as the roll I I2 in Figure 5.

After the roll I26 has been properly shaped, it may be employed to crush a grinding wheel as shown in Figure 9. The grinding wheel in Figure 9 is indicated at I22 and it will be observed that its configuration is complementary to that of the roll I26.

The final step in reproducing a contour is indicated in Figure 10 wherein the wheel I22 is grinding one or more form tools I24 to the proper configuration.

It will be apparent that the tools I24 carry exactly the same shape as the original tool I I4 and may therefore be utilized in the same production process from which the tool I I4 is taken.

The wheel I22 may be maintained by the roll I26 which does not need to be removed from the shaft 56 once it is mounted thereon, while the said roll may be maintained by the shaving tool II8 which, likewise, does not need to be removed from the fixture I62.

The operations shown in Figures 5, 6 and 7 may be performed in the fixture 22 if desired, but it will be understood that a separate machine could 52:? be utilised-for these steps if desired: while retaining the carrying out of the final steps shown in Figures 8', 9 and 10 on the production machine onwhich the final product is produced.

It will be seen that the method and apparatus according to this invention are particularly well adapted for use by manufacturers having production processes which require theuse of 'form tools.

Essentially the method outlined in thisapplication is that of utilizing an oldfor-m tool for shaping a crushingroll; thereafter using the roll so shaped to form a wheel; grinding a second form tool by the wheel so shaped; shaving still another crushing roll to the proper configuration by the tool last ground; and forming a grinding wheel by the last mentioned roll. The grinding wheel dressed by the said last mentioned roll can then be utilized for reproducing the contour of the original form tool.

While the preferred method of this invention utilizes an; original form tool retired from a production operation, or taken therefrom, it will be understood that the original tool could be produced on an accurate tool grinding machine from a master layout or part print if desired. In either case an exact duplicate of the original form tool can be madebecause tools of this nature are not form relieved, being of the same configuration completelythrough their thickness. Thus, in utilizing a tool of this type, if the tool becomes worn,it can be restored to its original configuration by grinding a predetermined amount oif the Working edge thereof.

By providing the pivot shaft 28 at a position remote from the axis of the shaft 56, and at substantially the same horizontal level, the adjustments made in the angularity of the beds 24 and 30 will be such that the said roll will move substantially vertically over a Wide range of adjustment of the shoe 36. This is of advantage because the table can be reciprocated relative to the wheel by a fixed amount and always bring the grinding wheel and crushing roll to proper relative position. Also, substantially all thrusts on the crushing roll due to the wheel being pressed thereagainst will be carried by the shaft 32 and not transmitted to the pivot shaft 28.

It will be understood that the arrangement shown proposes unclutching the roll shaft 56 from its drive motor during the dressing of the Wheel and that the wheel is driven at low speed during the dressing cycle. However, this invention also contemplates driving the shaft 56 and permitting the wheel to idle during the dressing cycle if it should be so desired.

It will be understood that this invention is susceptible to modification in order to adopt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications Within this invention as may fall within the scope of the appended claims.

I claim:

1. The method of producing dressing rolls for shaping production grinding wheels to a predetermined contour which comprises: mounting a unit having the desired contour in radial alignment with a crushing roll; shaping said crushing roll to a, reverse configuration by contacting said unit thereto through relative radial movement of said unit and roll; bringing said formed roll into co-planar surface contact with a grinding wheel and crushing the same in pressured revolving engagement to a positive reproduction of the original contour; bringing the said grinding wheel into true radial disposition with a, blank unit and.

' tion of the original unit.

2. The method of producing dressin rolls for shaping production grinding wheels toa predetermined contour which comprises: mounting a unit having the desired contour in radial alignment with a crushing roll; shaping said crushing roll to a reverse configuration by contacting said unit thereto through relative radial movement of said unit and roll; bringing said formed roll into co-planar surface contact with a grinding wheel and crushing the same in pressured revolving true radial disposition with a blank unit and grinding a surface of the same to produce a re verse reproduction of the desired contour; mounting said reversed unit in radial alignment with a co-planar surface contact with and crushing a said production grinding wheel in pressured revolving engagement to a negative reproduction of the original unit by movement of said roll in an arcuate path intersecting the periphery of said grinding wheel at a point tangent to a radius plane of said grinding wheel.

3. The method of reproducing contours by means of grinding and production grinding wheels which comprises: mounting on a support a member having a shape it is desired to reproduce; moving the member into engaegment with the surface of a crushing roll with the cutting edge of said member having all parts thereof in true radial disposition relative to said roll; forming said crushing roll to the shape of said member by rotating said roll relative to said member; bringing the said formed roll into co-planar surface contact with said grinding wheel and crushing the same in pressured revolving engagement to a positive reproduction of the original contour; bringing the grinding wheel into true radial disposition with a blank unit and grinding a surface of the same to produce a reverse reproduction of the desired contour; mounting said reversed unit in radial alignment with a crushing roll for shaving said roll to a shape which is a positive reproduction of the desired contour by driving said crushing roll in contact with said ground surface of said reversed unit; and bringing the shaped roll into co-planar surface contact with and crushing a said production grindin wheel in ment with the surface of the roll while the same' is rotating relative to said member and with the cutting edge having all parts thereof in true radial disposition relative to said roll; bringing the said formed roll. into co-planar surface contact with a grinding wheel and crushing the same in pressured revolving engagement to a positive reproduction of the original contour; bringing the grinding wheel into true radial disposition with a blank unit and grinding a surface of the same to produce a reverse reproduction of the desired contour; mounting said reversed unit in radial alignment with a crushing roll for shaving said roll to a shape which is a positive reproduction of the desired contour by driving said crushing roll in contact with said ground surface of said reversed unit; bringing the shaped roll into co-planar surface contact with and crushing a said production grinding wheel in pressured revolving engagement to a negative reproduction of the original unit whereby the complementary shape ground will be identical to the configuration of the original unit; and intermittently dressing the grinding wheel by the last mentioned roll.

5. The method of reproducing contours by means of grinding and production grinding wheels which comprises: mounting on a support a member having a, shape it is desired to reproduce; moving the member into pressured engagement with the surface of the roll while the same is retating relative to said member and with the cutting edge having all parts thereof in true radial disposition relative to said roll; bringin the said formed roll into co-planar surface contact with a grinding wheel and crushing the same in pressured revolving engagement to a positive reproduction of the original contour; bringing the grinding wheel into true radial disposition with a blank unit and grinding a surface of the same to produce a reverse reproduction of the desired contour; mounting said reversed unit in radial alignment with a crushing roll for shavin said roll to a shape which is a positive reproduction of the.

desired contour by driving said crushing roll in contact with said ground surface of said reversed unit; bringing the shaped roll into co-planar surface contact with and crushing a said production grinding wheel in pressured revolving engagement to a negative reproduction of the original unit whereby the complementary shape ground will be identical to the configuration of the original unit; and at least intermittently causing the truing device and the crushing roll to be brought into engagement with the complementary shaped edge of the truing device to maintain the shape of said crushing roll accurate within predetermined limits.

WILLIAM G. BALDENHOFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 553,802 Bardons et a1 Jan. 28, 1896 1,424,765 Larsson Aug. 8, 1922 1,513,757 Hanson Nov. 4, 1924 1,513,758 Hanson Nov. 4, 1924 1,714,246 Seibert May 21, 1929 1,896,533 Vuilleumier Feb. 7, 1933 1,951,875 Laabs Mar. 20. 1934 1,997,551 Romaine Apr. 9, 1935 2,135,202 Scrivener Nov. 1, 1938 2,211,685 Binns Aug. 13, 1940 2,385,644 Polk Sept. 25, 1945 2,436,527 Polk et a1 Feb. 24, 1948 FOREIGN PATENTS Number Country Date 492,591 Great Britain Sept. 22, 1938 515,397 Great Britain Feb. 25, 1938

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