US2791872A - Oscillating support for use on grinding machines - Google Patents

Description

May 14, 1957 w. N. WINEKA OSCILLATING SUPPORT FOR USE ON GRINDING MACHINES Filed April 6, 1953 I INVENTOR.

W/LBUR A! W/A/[AIq BY ATTOIP/Vf/J GSCILLATING SUPPORT FOR USE ON GRINDING MACHINES Wilbur N. Wineka, Detroit, Mich.

Application April 6, 1953, Serial No. 347,095

3 Claims. (Cl. 51-238) This invention relates to an oscillating support for use on grinding machines which is adapted for supporting relatively long slender workpieces and especially workpieces which are eccentric.

A long slender workpiece such as a relatively slender rod frequently has an eccentricity, caused by prior operations and treatment thereof. In grinding such a workpiece without a support, its center oscillates back and forth as the low portions and high portions rotate into contact with the grind wheel. The workpiece being long and slender, the stress urging it against the grind wheel is, for practical purposes, the same whether the high or low portions are in contact with the grind wheel and an equal cut is taken on all part of the workpiece. Hence, the eccentricity is not diminished during the grinding and as the radius of the workpiece decreases the eccentricity may even be accentuated. The same holds true when a rigid steadying rest is used.

An object of this invention is to provide a support for a long slender workpiece which will serve as an ordinary steadying rest when the workpiece has no eccentricity and which will interact with an eccentric workpiece in such a way that the eccentricity is diminished during the grinding. Another purpose of the invention is to provide a device having a simple structure which is economical of manufacture and very simple to operate. The invention comprises generally a frame which is securable to the table of a grinding machine and which carries a slide member. The slide has a nose member pivotably secured thereto which engages the workpiece. The nose member is adapted to be engaged cam-wise by any high point on the workpiece and oscillation thereby produced in the nose member urges the workpiece toward the grinding surface when high portions are in contact therewith and urges the workpiece away from the grinding surface when low portions are being ground. The eccentricity of the workpiece is thereby reduced during the grinding. One embodiment of the invention is shown in the accompanying drawings of which the following is a brief description:

Fig. l is a perspective view showing the device in use in a grinding operation.

Pig. 2 is a side view partly in elevation and partly in section with some parts broken away and showing a lever arm in a generally upwardly extending position.

Fig. 3 is an end view taken on line 3-3 of Fig. 2 and showing the lever arm in a downwardly extending position.

Fig. 4 is an enlarged view showing detail in the joint between the nose member and the slide.

Fig. 5 is an enlarged detailed view showing the interaction of the oscillating nose member and a workpiece having an exaggerated high portion.

Fig. 6 is similar to Fig. 5 but showing the high portion of the workpiece in engagement with a difierent part of the nose member.

' A grinding machine shown in Fig. 1 has a rotating face nite States Patent plate 10, a table 12, a tail stock 14 and a grind wheel 16. A long slender workpiece 18, shown as having a high portion 19 (Figs. 5 and 6), has one end supported by a center 20 in the tail stock 14 and has its other end secured to the face plate 10 by suitable means such as a dogleg chuck 22. The oscillating support 24 which is the subject of this invention is secured to the table 12 and is positioned to provide proper support for the workpiece 18. The face plate 10, acting through the chuck 22, rotates the workpiece 18 and the grind wheel 16 rotates, the directions of rotation being indicated by arrows.

The oscillating support 24 includes a frame member- 26, a slide member or cartridge 28, an oscillating nose member or workpiece engaging element 30 and an advancing unit 32. The frame member 26 has a base portion 34 which is securable to the table 12 of the grind-' ing machine, a vertical column portion 36 and a receiver portion 38 extending angularly upward from the column portion 36. The receiver portion 38 has a passageway or guideway 48 extending longitudinally therethrough, which preferably has a round cross section and through which the slide member 28 may slidably extend.

The slide member or cartridge 28 has a tubular housing or casing 42 with one closed end 44 and preferably with a hexagonal exterior shape, having edges 42 which engage the walls of the passageways 40. A threaded adjustment member or bolt 46 is slidably inserted into the open end of the housing 42 and an adjustment nut 48 is threaded thereonto. The adjustment nut abuts against the open end of the housing 42, so that by the turning of the nut, the distance by which the bolt 46 extends into the housing may be adjusted and the slide thereby extended in lentgh or shortened. The bolt is prevented from turning in the housing by the interaction of a keyway 50 in the bolt 46 and a pin 52 extending inwardly from one side of the housing 42. The bolt 46 terminates at its upper end in an inwardly tapering portion 54 (Fig. 4) surmounted by ball portion 56 adapted for ball and socket type of engagement with the oscillating nose member 38.

One end of the nose member 30 has a recess 58 which engages the ball 56 in a ball and socket type of joint. The recess is preferably cylindrical and the fit between the recess and ball is loose enough to permit the nose member to pivot freely relative to the slide. The edges 60 of the recess are tapered outwardly in order to engage the tapered sides of the portion 54 flatly when the nose member is axially disaligned from the bolt 46. The portion 62 of the nose member which defines the recess 58 has apertures 64 through which the end per tions 66 of a wire spring 68 may extend. In the unstressed condition of the spring the distance between its end portions 66 is smaller than the diameter of the ball 56 so that the spring serves to secure the nose 30 to the ball in a snap over type of engagement. The portion of the nose member 36 which engages the workpiece 18 may be advantageously shaped and in the form of the invention shown two angularly disposed faces 70 and 72 are provided which engage the workpiece as shown in Figs. 5 and 6. Nose members of different sizes may be used in grinding workpieces of different diameters.

The advancing unit 32 has a wheel member 74, an eccentric 76 and an axle member 77 which extends through apertures in the wheel member and eccentric. The axle member has a bearing portion 78 which carries the wheel member and a ratchet portion 80 which lies within the aperture in the wheel member 74. A pawl 82 is secured into a radially extending position within the wheel by means of a spring 84 backed by a screw 86 secured to the wheel member 74. The ratchet and pawl connection secures the wheel member to the axle member so that the two will normally rotate together but so that one may be rotated relatively to the other if desired. The ratchet and pawl are preferably adapted so that the wheel member may be rotated in only one direction around the axle member. A threaded lever arm 88 extends radially outwardly from the wheel member 74 and threadedly secured thereto is a weight 99.

An opening 92 extends through the upper part of the column portion 36 of the frame member in a direction transverse to the opening 40 through the receiver portion 38. A hearing 94 is disposed within the opening 92 and carries the mile 77'. The wheel member 74 and the eccentric 76 are secured on opposite sides of the frame member 26 by nuts 96 threaded on the ends of the axle. The eccentric is positioned to engage the lower end 44 of the slide 23. The advancing unit is freely rotatable with respect to the frame member 26.

For convenience of operation, the eccentric 76 may have an index mark 98 at its low point, another index mark 100 may be placed on the column portion 36 of the frame. member and the surface of the wheel member 74 may he graduated as shown at 101.

In. use an oscillating nose member 30, selected for its size relative to the workpiece 18 and for the cod formation of its workpiece engaging surfaces 70 and 72, is secured to the slide by slipping the recess or socket portion 58 over the ball portion 56 of the adjustment bolt 46. The end portions 66 of the spring 68 snap over the wide part of the ball and secure the nose member thereto. The support 24 is secured to the table 12 of the grinding machine. The low point of the eccentric 76 as indexed at 98 is placed in engagement with the lower end 44 of the slide and the lever arm is turned through the action of the ratchet and pawl to a vertically downward position. By the turning of the nut 48 one way or the other, the adjustment bolt is advanced or retracted and the nose member 39 is thereby properly positioned with respect to the workpiece 18. The nose member 30, the workpiece 18 and the grind wheel 16 are thus disposed in the relative positions indicated in Fig. and 6. While the eccentric 76 is held in position, the lever arm 88 is turned relatively thereto to its proper initial position and theweight 904s properly positioned thereon.

When the lever 88 is positioned at an angle to the vertical, gravity acting upon the lever arm and the weight 90 tends to rotate the wheel portion 74, the axle 77 and the eccentric 76, thereby urging the slide 28 in a direction toward the workpiece and holding the nose member into engagement with the workpiece. The nose member engages the workpiece with a force which may be varied according to the nature of the workpiece by adjusting the angle of the lever arm 88 to the vertical, by adjusting the position of the weight 90 on the lever arm, and by the use of additional weights, or a smaller weight, etc.

As the diameter of the workpiece 18 is decreased by removal of material therefrom during the grinding operation, the slide is advanced and the oscillating nose member maintained in engagement with the workpiece by the action of the advancing unit. The amount of rotation of the wheel member 74 during the grinding may be measured bymeans of the graduations 101 thereon and the index 100 on the frame member (Fig. 1); when the throw of the eccentric 76 is known the distance through which the slide is advanced and the depth of cut on the workpiece may be determined. Since the downward vertical position of the lever arm 88 is the limiting position of the advancing unit, the advancement of the slide and hence the depth of cut may be limited as desired by varying the initial angle between the lever arm 88 and the downward vertical,

In order to accomplish the grinding, the grind wheel must be urged firmly against the workpiece which tends to bow the workpiece horizontally and the cutting force tends to how the workpiece vertically downward. The resultant force tends to bow the workpiece in a direction between the horizontal and the vertical. The support 24 provides support against this bowing of the workpiece. When the workpiece has no eccentricity the support 24 thus serves as an ordinary steadying rest. However it is an important part of this invention that when the Workpiece does have an eccentricity it is employed as a cam to oscillate the nose member 30, causing the nose member in turn to urge the workpiece toward the grind wheel when the high portion is being ground and away from the grind wheel when the low portions are being ground.

Assuming that the support 24 has been properly positioned and that the grinding machine is in operation with the workpiece 18 and the grind wheel 16 rotating in the directions indicated by the arrows, when the high portion 19 of the workpiece rotates into contact with the surface it acts as a cam forcing the surface 70 away from the grind wheel. This results in a rotation counterclockwise, as the drawings are viewed, of the entire nose member 39 about the center of the ball 56. This rotational movement is transmitted to the workpiece by the surface 72 and has a component tending to move the workpiece away from the grind wheel. When the high portion 19 is thus engaging the surface 79, low portions of the workpiece are in contact with the grind wheel and the grinding force is at its minimum.

When the high portion 19 rotates into contact with the surface 72, it acts as a cam causing rotation of the nose member 30 in a clockwise direction. This rotational movement is transmitted to the workpiece 18 by the surface 70 and urges the workpiece into tighter contact with the grind wheel 16. During this period high portions of the workpiece are in contact with the grind wheel and the grinding force is at its maximum. Hence the depth of cut is least when low portions of the workpiece are in contact with the grind wheel and greatest when high portions are in contact with the grind wheel so that the eccentricity of the workpiece is reduced during the grindmg.

The oscillation of the nose member 30 during the grinding is illustrated in greatly exaggerated manner in Figs. 5 and 6. The lines a and b are radii drawn from the center of the ball 56 about which the nose member rotates in its oscillation. Line a indicates the position of the center of the workpiece and the nose member when the high portion 19 is in engagement with the surface 70. Line b indicates the position of the center of the workpiece and the nose member when the high portion 19 is in engagement with the surface 72. The high portion 19 is also greatly exaggerated for purposes of illustration. Figs. 5 and 6 show the nose member 30 set so that during its oscillation it will not rotate over the dead center position with respect to the slide member, in order to avoid aberrant grinding. However, the invention has been found to operate satisfactorily even though the oscillation of the nose member does traverse the dead center position.

In practice it has been found advantageous to first grind the middle of the workpiece with the grind wheel stationary axially of the workpiece and aligned with the support. The grind wheel is advanced radially of the rod in several small steps until the rod has been ground round; the pressure of the nose member on the workpiece is relieved momentarily between steps by the lifting of the lever arm 88. The red as a whole is then ground in the normal manner with the wheel passing axially back and forth through the length thereof. By this method the entire rod may be ground to a round shape with the removal of less material from the workpiece than would be necessary if the middle portion thereof were not first ground round. Normaly the support remains in a statioriary position preferably at the middle of the workpiece; however it may be moved along the workpiece with the, grind wheel if desired. Also more than one support may be used to support a single workpiece if desired.

Such terms as upward, downward, etc. are used herein merely as convenient terminology and not as delimitations.

I claim:

1. In combination with a grinding machine having a grind Wheel and a table, a workpiece support comprising, a frame on said table, means forming a rectilinear guideway on said frame, a rotatable eccentric on said frame, said guideway extending directly toward said eccentric and toward said grind wheel, a cartridge including an outer housing axially slidable on said guideway and including an element slidable axially in said housing, said housing having one end portion engaging said eccentric, said element projecting out of the other end of said housing and having a workpiece engaging member thereon generally adjacent said grind wheel, threaded means axially extensibly interconnecting said housing and element, whereby to selectively position said workpiece engaging member relatively to said grind wheel and gravity responsive means operative to rotate said eccentric for advancing said cartridge and member thereon directly toward said grind wheel.

2. The device defined in claim 1 wherein said eccentric is positioned on one side of said frame, said gravity responsive means is positioned on the other side of said frame, said eccentric and gravity respnosive means being operably connected by an axle extending through said frame.

3. The device defined in claim 1 wherein said eccentric and gravity responsive means are mounted on an axle on said frame, said gravity responsive means being mounted on said axle through a ratchet and pawl structure, whereby to selectively position said gravity responsive means relatively to said eccentric and limit the advancement of said cartridge and member.

References Cited in the file of this patent UNITED STATES PATENTS 249,436 Wilson Nov. 8, 1881 510,454 Wagner et a1. Dec. 12, 1893 732,314 Norton June 30, 1903 802,334 Smith Oct. 17, 1905 886,293 Hanson Apr. 28, 1908 915,175 Hanson Mar. 16, 1909 1,167,049 Cooley Ian. 4, 1916 1,549,567 Baldwin N Aug. 11, 1925 1,789,408 Hultgren Jan. 20, 1931 1,870,817 Maag Aug. 9, 1932 1,961,091 Smith May 29, 1934 2,033,324 Caster Mar. 10, 1936 2,324,958 Silven July 20, 1943 2,332,837 Bauer Oct. 26, 1943 2,378,851 Ibbott June 19, 1945 2,478,607 Theler et al. Aug. 9, 1949 2,563,302 Atkinson et al. Aug. 7, 1951 2,579,995 Atchison Dec. 25, 1951 2,592,229 Alexay Apr. 8, 1952 FORElGN PATENTS 21,920 Great Britain Nov. 3, 1915 147,572 Great Britain July 8, 1920 581,618 Germany July 31, 1933

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