US3124912A

US3124912A - jessup

Info

Publication number: US3124912A
Authority: US
Publication date: 1964-03-17
Anticipated expiration: 1981-03-17

Description

March 17, 1964 w. F. JESSUP MACHINE TOOL WORKPIECE SUPPORT Original Filed June 27, 1960 U HMMWM 2i.

INVENTOR.

W/LBUR F; JESSU March 17, 1964 w. F. JESSUP MACHINE TOOL WORKPIECE SUPPORT 2 sheets-sheet 2 Original Filed June 27, 1960 P Y may M m R 3% m w .7 F m f a $3 3 I 3 5 Jrn. HF. Q? E m 1Q gm 9 4 a J x United States, Patent O 3,124,912 MACHEJE TOOL WORKPECE SUPPORT Wilbur F. .lessup, Lyons, France, assignor to The Cincinnati Milling Machine (Iompany, Cincinnati, Gino, a

corporation of (Bhio Continuation of application Ser. No. 39,138, June 27,

1960. This application Apr. 12, 1962, Ser. No. 188,612 5 tllaims. (Cl. 51-238) The present invention relates to a workpiece locating and supporting mechanism for a grinding machine in which the workpiece is rotated about a support determined axis.

This application is a continuation of application Serial Number 39,138, filed June 27, 1960, now abandoned.

In a grinding machine of the type described in U.S. Patent 2,478,607 issued August 9, 1949 one end of a workpiece of circular cross section is held, usually magnetically, against a rotating face in eccentric relation thereto. Shoes are located adjacent the face plate in front of the grinding wheel and are positioned to support the workpiece which extends longitudinally from the face plate. The rotation of the face plate rotates the workpiece and the eccentric relationship between the workpiece and the face plate serves continuously to urge the workpiece into the shoes, the workpiece sliding on the face plate as it is held in a fixed position for grinding by the shoes. Thus the face plate rotates the workpiece and urges it into the shoes, and the shoes support the workpiece extending from the face plate and positively locate the workpiece in a fixed position for grinding. As the workpiece diminishes in size, the workpiece shifts toward the shoes to maintain contact therewith and sometimes, as when the shoe is contoured to receive the workpiece, at least one of said shoes is swingable in a lateral plane to follow the diminishing and shifting workpiece. In conventional workpiece supports, although one or both shoes may be pivotal in a lateral plane, they do not yield, or move away from the grinding wheel, in that plane so that they provide a positive locating force for the workpiece resisting lateral shifting thereof beyond that incident to the diminution of the workpiece.

However, the laterally unyielding force provided by the shoes produces a problem when the end of the workpiece held by the plate is not perfectly square, particularly when the workpiece is not relatively short. Under these conditions the workpiece has a tendency to wobble as it is rotated and, during the portion of the cycle of rotation of the workpiece when the high side of the workpiece engages the shoe, the force exerted by the shoe on the workpiece increases, and tends to become concentrated at the far end of the shoe. This force acts on the workpiece in the opposite direction as the force exerted thereon by the magnetic face plate, and, because of the distance between the forces on the workpiece, one edge of the workpiece can be lifted off the face plate, momentarily interrupting the application of the driving force to the workpiece which has a deleterious effect on the grinding. Thus, the unyielding locating force created by the shoe varies as the workpiece wobbles during rotation and, on each cycle, builds up to sufiicient magnitude which, if the far end of the shoe is spaced far enough from the face plate, can lift the edge of the workpiece oil the face plate.

In the present invention, there is provided a workpiece support which, although providing a positive locating force for the workpiece, automatically reduces the build up of force at the far end of the shoe and, at the same time, offsets the tendency of this force to rock the workpiece on the face plate. This is accomplished, in the illustrative examples of the invention shown, by provid- 3,124,912 Patented Mar. 17, 1964 ing two shoe members circumferentially spaced about the face plate and workpiece, one below the workpiece and one at the side of the workpiece opposite the grinding wheel. Each of these shoe members extends longitudinally (i.e. in the direction of the face plate axis) and contacts the workpiece near the end of the workpiece remote from the face plate and near the end which engages the face plate. Each shoe member is pivoted, for swiveling in a longitudinally extending plate, about a fixed pivot axis which, in the longitudinal direction, is between the extreme ends of the shoe (but preferably spaced from the periphery of the workpiece) so that these extreme ends, which are engaged with the workpiece, must, when they move, move in opposite directions. With this construction, each shoe member maintains contact with both ends of the workpiece and tends to balance the forces applied against the ends. As the high side of the workpiece first contacts a shoe and the force exerted by the rotating workpiece on the far end of the shoe member begins to build up, the far end of the shoe member tends to yield, increasing the force exerted by the near end of the shoe member on the end of the workpiece engaged with the face plate. As the force applied to the far end of the shoe member by the high side increases, the shoe member swivels and the workpiece, instead of rocking on the face, is shifted by forces applied at both ends of the workpiece. Since the workpiece is continuously urged into the shoes by the rotating face plate, when the workpiece rotates to present its low side to a shoe member and the force of the workpiece on the far end of the shoe tends to diminish accordingly to a greater extent than the workpiece force on the near end of the shoe, the shoe member swivels in the opposite direction and the workpiece shifts accordingly. Thus, since the wobbling workpiece is continuously urged into the shoe members, the shoe members oscillate about their fixed axes, continuously applying forces at both ends of the workpiece which cause the workpiece to shift instead of rocking on the face plate and the driving force on the workpiece is uninterrupted.

During grinding, the high portions of the workpiece are reduced, and the oscillations of the shoe members diminish, until the surface presented to the cutting face of the grinding wheel is parallel therewith. At this time the workpiece is perfectly square with the end engaging the face plate and the shoe members cease to oscillate, thereby positively olcating the workpiece as the grinding wheel brings the workpiece to final size.

It is therefore an object of the present invention to provide a workpiece locating support for a grinding machine in which the workpiece is rotated by a face plate, which support will not tend to rock an eccentric or out of square workpiece on the face plate. It is another object of the invention to provide a workpiece support for relatively long workpieces.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

' In the drawings:

FIG. 1 is a view, in elevation, of the workpiece supporting mechanism of the present invention;

FIG. 2 is a view taken on the line 2-2 of FIG. 1 showing the mechanism thereof in plan;

FIG. 3 is a view taken on the line 3-3 of FIG. 1;

FIG. 4 is a view in plan showing in solid lines, the position of an out-of-square workpiece and the position of a supporting shoe member as the high side of the workpiece engages the shoe member; and, in dotted lines, the position of the workpiece and shoe member when the low side of the workpiece engages the shoe member; and

FIG. shows the workpiece of FIG. 4, and the position of the shoe member, at the end of the grind.

There is shown in FIGS. 2 and 3 a magnetic driver 6 of a grinding machine rotatable about a longitudinal axis 611, the driver defining an annular face plate 6a adapted to slidably grip one end of a workpiece 7. When gripped by the face plate, the workpiece extends longitudinally therefrom in front of the grinding wheel 65 (see FIG. 1) for grinding. The workpiece 7 shown for illustrative purposes in FIGS. 1, 2 and 3 is in the form of a truncated cone which, although rounded at the end gripped by the face plate, has an annular flat 7a machined thereon for engagement by the annular face plate. As shown best in FIGS. 1 and 2, a bracket 10 has a base 11 with

side flanges

12 and 13 secured to the bed 14 of the grinding machine by bolts 9 which extend through longitudinally extending slots 8 in the flanges to permit adjustment of bracket It longitudinally in respect to the workpiece 7. The bracket 15) has a front wall 15 with

side flanges

16 and 17. Extending rearwardly from the front wall are two spaced

webs

19 and 20. The front wall has secured thereto by bolts 21 extending through vertically elongated slots 22 in the wall flanges, a vertically adjustable mounting plate 23 having adjustable feet 24 and 25 which seat on a shell 26 on the forward side of the front Wall 15. The mounting plate 23 defines a fixed support on which the lower shoe member 27 is pivotally mounted by pivot pin 28 for swiveling in a longitudinally extending plane about the pivot point defined by pivot axis 28a. The amount of swivel of shoe member 27 is limited by adjustable feet 29 and 30 which, at the extreme limits of swivel respectively engage a shelf 31 extending from the lower end of the mounting plate 23. Bolts 32 secured in mounting plate 23 extend through slots 33 in shoe member 27 to retain the shoe member on the pivot pin 28 but do not clamp the shoe member against the mounting plate. The shoe member 27 has a workpiece engaging portion 34 which engages the workpiece along its length including two extreme points of engagement 34a and 34b at each end of the workpiece. The pivot axis 23a is between the extreme workpiece engaging points 34a and 34b in the longitudinal direction, and spaced from the periphery of the workpiece, as shown in FIG. 3.

A block 49 is received between webs l9 and 2 0 and has slots 41 therethrough to receive clamping bolts, some of which are shown at 42, which secure the block in desired adjusted position, the block being shown in its extreme upper position in FIG. 1. Received on block 40 is a mounting plate 43 secured thereon by bolts 44 which extend through laterally extending slots 45 in plate 43 to permit lateral adjustment thereof relative to workpiece 7. The lateral adjustment of plate 43 is accomplished, when bolts 44 are loosened, by screw 46 which engages plate 43 at its far end and is threadedly engaged in block 47 connected to block 40. Plate 43 defines a fixed support on which a shoe member 49 is pivotally mounted by a pivot pin 43, having axis 48a, which defines a pivot point about which shoe member 49 swivels in a longitudinally extending plane. The shoe member 49 is retained on the pin, but not clamped to the plate 43, by the nut 59. The workpiece engaging portion of shoe member 49 comprises two

pad members

51 and 52 longitudinally spaced along the length of the workpiece 7 and each swingable in a plane extending laterally relative to the workpiece on pivot pins 53 and 54, respectively, permitting the pad members better to follow the workpiece as it shifts downwardly on the face plate during grinding. Each pad member comprises two

pad portions

55 and 56 each swingable in a lateral plane about a pivot pin, 57 and 58 respectively, to maintain better engagement with the diminishing periphery of the workpiece during grinding. The pivot axis 48a is between the

pad members

51 and 52 in the longitudinal direction, and spaced from the periphery of the workpiece, as shown in FIG. 2.

Preferably, as shown best in FIGS. 2 and 3, the pivot axes 28a and 480 are not at or adjacent the periphery of the workpiece but are spaced therefrom as shown. This is desirable so that there will be a small relative axial movement between the shoes and the workpiece as the shoe members swivel. This movement produces a damping force which tends to prevent resonance and aids in diminishing the oscillations of the shoe member as the grind proceeds and the wobbling of the workpiece is reduced.

As shown in FIGS. 1, 2 and 3, the workpiece 7 is mounted on face plate 6a of driver 6 with the longitudinal axis 7b of the workpiece eccentric relative to the longitudinal axis of rotation 6b of the driver whereby the workpiece is rotated by the rotating driver and is continuously urged thereby into the

shoe members

27 and 49 which are circumferentially spaced about the face plate and workpiece, shoe member 27 below the workpiece and toward the grinding wheel and shoe member 49 at the side of the workpiece away from the grinding wheel 65.

The operation of shoe members which swivel as

shoe members

27 and 49 in a plane extending in the direction of the driver axis (i.e. longitudinally with respect to a workpiece gripped by the driver) is illustrated in FIGS. 4 and 5 which show a cylindrical workpiece 66 mounted eccentrically relative to the longitudinal axis of rotation 6b of the rotating driver 6. The end 66b of the workpiece which is slidably gripped by the driver is not perfectly square and the workpiece wobbles as it is rotated. The workpiece is continuously urged into longitudinally swivelable shoe members mounted similarly to the shoe members of FIGS. 1, 2, and 3 (only portions of one being shown opposite the grinding wheel for clarity), said shoe members having a workpiece engaging portion which engages the workpiece along its length, either continuously, or through spaced pads as 67 and 68. The workpiece engaging portion of the shoe member shown in FIG. 4 has two extreme longitudinally spaced points of contact with the workpiece, the extreme point of contact 67a near the driven end 66b of the workpiece and the extreme point 68a near the far end 660 thereof. As the high side 66d of the workpiece (i.e. the side which inclines away from the axis 6b of rotation of the driver because end 66b is not square) bears against pad 68, pad 68 is urged away from the longitudinal axis 6b of the driver and the pad 67 is therefore urged toward that axis, shifting the workpiece to the position shown in solid lines in FIG. 4. Thus the end 66b is shifted relative to the plate 6a instead of rocking thereon by virtue of the lateral force applied by the near pad 67. As the low side 66c of the workpiece swings into registration with

pads

67 and 68 the force against the far pad 68 is reduced to a greater extent than the force against the near pad 67 and, since the workpiece is continuously urged into the shoes by the driver 6, the near pad 67 yields and the shoe member swivels until the pads and the workpiece are positioned as shown in dotted lines in FIG. 4. The grinding Wheel 69 operates on the high side of the workpiece, thereby squaring up the workpiece. Thus, the oscillation of the shoe member diminishes and, as the grind continues, the central axis 66 of the workpiece becomes parallel with the axis of rotation 6b of the driver and the oscillation of the shoes stop. At this time the shoes are securely held against lateral yielding by their fixed pivot pin and they positively locate the workpiece so that when the advance of the grinding wheel is stopped at a predetermined point, the workpiece will be ground to precise size with the longitudinal axis 66 thereof square with the end 66b.

I claim:

1. In a grinding machine the combination comprising a workpiece driver having a face plate rotatable about a longitudinal axis to slidably engage in eccentric relation one end of an elongated workpiece of circular cross section to rotate said workpiece for grinding, at least two shoe members circumferentially spaced about the face plate each of said shoe members pivotally mounted for swiveling about a fixed axis during grinding in a longitudinally extending plane, each of said shoe members extending longitudinally along the workpiece to engage the periphery of the workpiece and provide the sole support for the workpiece in one lateral direction, each shoe member having two longitudinally spaced extreme workpiece engaging contact points on each side of the pivot point in the longitudinal direction to engage the workpiece near its opposite ends.

2. In a grinding machine having a face plate rotatable about a longitudinal axis adapted to slidably grip one end of an elongated workpiece of circular cross section whereby said workpiece extends in the longitudinal direction from the face plate during grinding and is rotated by the face plate, two fixed supports circumferentially spaced about a workpiece mounted on the face plate for grinding, a shoe member mounted on each of said supports for swiveling during grinding in a longitudinally extending plane about a pivot axis, each of said shoe members having workpiece engaging portions adapted to engage the periphery of the workpiece along its length, the extreme ends of said workpiece engaging portions spaced, in the longitudinal direction, on each side of the pivot axis to engage the workpiece near its opposite ends, the workpiece engaging portions of at least one of said shoe members being swingable during grinding on the shoe member in a laterally extending plane, and each of said pivotal shoe members providing the sole locating support in one lateral direction for the workpiece.

3. In a grinding machine having a face plate rotatable about a longitudinal axis adjacent the grinding wheel adapted to slidably grip one end of an elongated workpiece of circular cross section whereby said workpiece extends in a longitudinal direction from the face plate in front of the grinding wheel and is rotated by the face plate for grinding, a first fixed support at the side of a workpiece mounted on the face plate away from the grinding wheel, a first shoe member mounted on said sup port for swiveling during grinding in a longitudinally extending plane about a pivot axis spaced from the periphery of the workpiece, said shoe member having a pair of longitudinally spaced pad members adapted to engage the periphery of the workpiece along its length, said pad members spaced in the longitudinal direction on each side of the pivot axis to engage the workpiece near its opposite ends, each of said pad members swingable during grinding in a lateral plane normal to said longitudinal plane and comprising two pad portions swingable during grinding in said lateral plane, said first pivotal shoe member providing the sole lateral locating support for the workpiece at the side thereof opposite the grinding wheel, a second fixed support below a workpiece mounted on the face plate, a second shoe member mounted on said second support for swiveling during grinding in a longitudinally extending plane about a pivot axis spaced from the periphery of the workpiece, said shoe member having a workpiece engaging portion adapted to engage the periphery of the workpiece along its length, the extreme ends of said workpiece engaging portion of the second shoe member spaced, in the longitudinal direction, on each side of the pivot axis to engage the workpiece near its opposite ends, said second pivotal shoe member providing the sole lateral support for the workpiece below the workpiece.

4. In a grinding machine, the combination comprising, a workpiece driver having a face rotatable about an axis to slidably engage one end of a workpiece extending in the axial direction therefrom and rotate the same for grinding, at least two shoe members circumferentially spaced about the face plate, each of said shoe members pivotally mounted for swiveling about a fixed pivot point during grinding in a plane extending in the axial direction, each of said shoe members engaging the periphery of the workpiece on both sides of the pivot point in the axial direction and each of said shoe members providing the sole support for the workpiece in one lateral direction.

5. Mechanism to grind a workpiece to a final conformation of circular cross-section with a central longitudinal axis perpendicular to one end face of the workpiece comprising in combination, a grinding wheel, a rotatable workpiece driver to slidably engage said one end of a workpiece to rotate said workpiece in front of the grinding wheel, a first shoe member located below a workpiece engaged with the driver and a second shoe member located beside a workpiece engaged with the driver and opposite the grinding wheel, each of said shoe members pivotally mounted for swiveling in a longitudinally extending plane during grinding about a fixed axis spaced from the workpiece, each of said shoe members engaging the periphery of the workpiece on both sides of the pivot axis in the longitudinal direction and each of said shoe members providing the sole support for the workpiece in one lateral direction.

References Cited in the file of this patent UNITED STATES PATENTS 642,452 Hull Ian. 30, 1900 1,364,006 Swanson Dec. 28, 1920 1,393,046 Singer Oct. 11, 1921 2,182,311 Cole Dec. 5, 1939 2,329,191 Favini Sept. 14, 1943 2,478,607 Theler et a1. Aug. 9, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0, 3 l24 9l2 March l7 1964 Wilbur Fa Jessup l't iehereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 9 for "plate" read plane line 4T for olcating read locating column 3 line 30, for

"shell" read shelf Signed and sealed this 21st day of July 1964.

1 (SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ESTON G. JOHNSON Attesting Officer