US2621447A - Grinding machine - Google Patents

Description

Dec. 416, 1952 w; BER

GRINDING MACHINE Filed March 20, 1951 2 SHEETS-SHEET 1 6a INVENTOR.

W/-L-/EL/V/ BEER BY 6 aaa?, gama/1mm? A TTORNE YS Dec. 16, 1952 w. BEER 2,621,447

GRINDING MACH-INE Filed March 20, 1951 2 SHEETS-SHEET 2 m mwa JNVENToR. WIL HEL M BEER f4 TTOE NE Y-S Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE Application March 20, 1951, Serial No. 216,545 In Germany April 3, 1950 7 Claims.

direction, and then in the other, the valve be- 1'* ing lifted between various rotations and the grinding paste replenished. The degree of turning, or the number of revolutions during the turning in one direction, is irregular so that a kind of a step by step overlapping process prevents over-ground surface areas, such as would occur if the turning were always started and stopped at the same point. Furthermore, the hand operation permits the Valve to center itself With respect to the valve seat, the hand manipulated turning instrument yielding to any inclinations necessary for centering.

In the known mechanical valve grinding machines, the desirable technique of hand grinding has not heretofore been achieved. In one type of machine the valve is periodically lifted from the seat so that the grinding paste can be replenished, but the rotation of the valve is always in the same direction. This permits any errors of adjustment between the seat and the valve to become accentuated during the grinding. In another form of machine, the valve is rotated rst in one direction and then in the other by a system of gears and levers, but the valve constantly engages the seat. Therefore, the grinding paste cannot be replenished, and any foreign object which may have gotten into the paste in the beginning will produce objectionable scores in the valve seat.

The objects of the instant invention are to produce a machine which very closely simulates the hand grinding of valves, plugs, or stoppers, into their seats; to produce a machine in which the valve being ground is periodically lifted from its seat, but is not re-seated at the same point; to produce a machine in which a reversal of direction of grinding takes place as the valve is lifted from its seat; to produce a machine to obtain a step by step progressive overlapping grinding process; and to produce a self-centering table for holding the workpiece containing the valve seat.

In general, these objects of the invention are obtained driving a spindle in alternate directions by a pair of friction disks. A sleeve telescopically engages the spindle and is splined thereto, the

lower edge of the sleeve carrying a chuck for holding the valve. A cam system causes the friction disks to turn the spindle successively in alternate directions, and to lift the sleeve at the moment the spindle is being changed in its direction of rotation. This cam system also holds the valve free of the seat for a longer time in one direction of spindle rotation than the other, so that when grinding is resumed successively, a progressive step by step overlapping grinding occurs. The workpiece containing the valve seat is held on a table which is self-adjusting in any horizontal direction, and self-inclining to any angle from the vertical, so that the valve seat automatically centers itself with respect to the Valve.

The means by which the objects of the invention are obtained are more fully described with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view, partly in section, of the machine;

Fig. 2 is a longitudinal cross-sectional view through the grinding spindle and chuck carrying sleeve;

Fig. 3 is an enlarged detailed view of a portion of a driving disk;

Fig. 4 is a front View, partially in section, of the supporting table;

Fig. 5 is a side view, partially in section, of Fig. 4; and

Fig. 6 is a schematic representation of the grinding process produced by the machine.

In Fig. 1, a base 2 supports a frame 4, housing motor M which is connected by belt 6 to sheave 8, driving a worm gear I0. This worm gear in turn drives gear I2 secured to shaft I4, which is journaled at each end in the upper portion I6 of frame 4. Slidably mounted on and splined to shaft I4 are two friction disks I8 and 2D, respectively. These disks are urged toward the center of the shaft by springs 22 and 24, respectively. Intermediate the disks I8 and 20 is a cam '26 splined to shaft I4 and slidable thereon by means of a stationary pin 28, which is Xedly held to housing portion I6 by means of a bracket 30. A cam 32 is also xed to shaft I4 for a purpose later to be described.

A vertical spindle 33 is journaled in a bracket 34 appropriately secured to housing portion I 6, the bearing including conventional thrust bearings (not shown) against vertical displacement. The upper end of spindle 33 carries a friction disk 36, while the lower end of spindle 33 eX- tends downwardly into bearing 38 mounted Vin housing portion I 6. A sleeve 40 is telescoped over the spindle 3 and is splined thereto, the sleeve extending through bearing 38. The lower end of this sleeve carries a chuck 42 which holds the valve, plug, or stopper 44.

A nut 46, which includes an annular collar, is threaded on sleeve 48. A compression spring 48 extends between this nut 46 and a collar 59, which abuts bearing 35.

A rod 52 held by brackets 54 to housing portion i, extends between cam 32 and a lever 56, which is pivoted at 53, and the other end of which engages nut 46. An adjustable spring @il is attached to one end of lever 55 in order to vary.

the tension thereon.

In Fig. 3 a portion of friction disk 2Q is illustrated, a similar construction existing for disk I8. 'These disks are composed of cast iron with copper plugs or rivets 62 inserted therein in order to increase the frictional qualities of the surfaces oi the disks. The periphery of the diskis provided-witha groove Ed. Oneface of the-disk has, a greaterA diameter thanthe opposite face, thus producing a flange 'c. Consequently, any oil which may accumulate on either face of the disk is by centrifugal force rst collected in groove $45, and then flows to the edge of ilange 66, from which it is flung from .the disk.

The operation of this portionrof the machine is as follows:

ShaftV l@ upon being rotated by motor lvl causes cam 26 to move either to the right, or to the left, in accordance with` the position of. the groove in the cam follower with respect to fixed pin 28. As the cam moves to theright, it will engage disk 20 and push it against the pressure of spring 2d out of engagement with disk 3B. At the same time, disk i8 will move under the pressure of spring 22 into engagement with disk 3,.and will rotate the disk connectedtc the spindle 33 and sleeve 4B. This rotation continues until cam 25 is againshifted, so that disk i8 becomes disengaged and disk 2) reengages disk 36 to rotate the spindle in the opposite direction.

At the moment either of the disksbecomes disengaged from disk 35, cam 32 comes into operation to push down rod 52` and thereby actuate leverA 5S to raise sleeve dragainst the pressure of spring 43. valve or plug 44 out of engagementvwith the valve seat and permit the grinding paste to be replenished.

Cam 32 is. formed to hold sleeve eil elevated whilere-engaged by either. of the driving friction disks, i8, 2Q, for aY longer period of time than the other. the sleeve is lowered to resume grinding, the valve in grinding engagement is always turned in. one direction a greater number of revolutions than it is turned in the opposite direction, thus causing aprogressive grinding in the direction of the greater number of revolutions. In Fig.Y 6 suchris schematically illustrated where a representsthe beginning of the grinding in, say, a clockwise direction, for a period of time represented by the solid line. At the point b, the rst driving disk has been disengaged from the spindle 34, and the second driving disk meets disk 36, and spindle 3d begins to revolve in the opposite direction, dash line c, but does not set the valve in the seat until sleeve 49 has been permitted to lower at d by reason of cam 32. By thetime the sleeve has lowered, the grinding extends only over aperiod of time, equalto the This, of course, will raise the- Theresult of thisis that whenk length of the solid line e, following which at j the sleeve is again lifted and the valve is disengaged from the seat during the length of time represented by the dash line g, plus the sleeve lowering time h, and grinding again starts as represented by the solid line z'. This grinding is thus repeated until the valve is ground in, it being noted that the point of re-engagement of the valve with its seat always varies progressively in one direction, with a step by step overlapping process.

The length of grinding for any series of objects can be determined experimentally, and then a time switch S, attached to motor M, set for the grinding of an object; the machine stopping itself when the grinding is completed. The pressureof thevalve on the seat can be adjusted by varying the tension on spring 68.

The supporting table is constructed so as to adjust itself to center the workpiece containing the valve seat, with respect to the valve. In general, the base 'lil is vertically,adjustableon tracks 2'secured to frame d, this. base being verticallymovable by means of a lift 14. Carried on the base is the table 76, shown in detail in Figs. 4 and 5, and upon which is mounted the workpiece 'il containing the valveseat.

Mount consists of a base plate 'I8 containing longitudinal grooves 88, anti-friction balls 82 moving in these grooves and supporting plate Sil for movement in the direction of grooves Sil. The upper surface of plate 34 contains a centrally extending groove 85 runningv at right angles to grooves 86..

A plate 565 rests on plate Bil, plate 8S having a projection 83 engaging groove 84a. Plate 83 is therefore movable at right angles to plate 3d, this movement being facilitated. by antifriction balls Scontained ingrooves 92j in the bottom surfaceof plate 86, saidgrooves 92 being parallel to groove 8130,. Plates 84 and,85. are

held on base plate I8 by means of ilange85 secured to plate. 'I8 and surrounding plates 84 and 8G.

plates against vertical separation.`

A plate S carrying jaws 96 is mounted on plate 8,6 by means of a ball and socket. 98. It is noted that the upper surface 81 of .plate 85 is slightly conical in shape with the locus of the apex at the ball and socket joint, which permits the` spherical ball to be held ini place.

upon platel 86 by means of holding plates. 198

screwed to plate 86, access to the heads of the position between the valve d, thek mount` 101s. raised to bring the seat into contact with valvev lid. Plates 8d and` 86 will adjust themselvesto center the valve seat with respect to the valve, while platell is slightly tiltable on socket 98.in order to compensate for any inclination of the valve withrespect to the valve seat. A substantially perfect centering is thus assured, and. grinding can begin without further adjustment.

The machine described substantially,` reproduces the technique.. of hand grinding and. all. of the advantagestherewith., Theseating of the,A

valve seatand the valve in the machine, isac.-

An inturned flange 85a extending along two parallel sides of plate 86 holds. the.

complished quickly and without the time necessary to obtain accurate centerings, as in former machines. The pieces having been set in place, the motor is started and the operation of grinding continued Without further attention, except for the replenishment of the grinding paste, until the valve has been ground in.

While for purposes of convenience the ma chine has been, for the most part, described with reference to grinding in of a valve, it is clear that the machine is useful for grinding in many other objects, such as stop cocks, bottle Stoppers, plug cocks, and plugs of various sorts.

Having now described the means by which the objects of the invention are obtained, I claim:

1. In a machine of the type described, means for grinding a valve-like plug into a seat comprising a at base plate, a work piece holder for a valve seat supported on and xed to said base plate against rotation and being free for parallel movement in all directions with respect to said base plate, means for holding a Valvelike plug into grinding engagement with the valve seat, means for rotating said holding means intermittently in successively opposite directions, and means for disengaging said holding means and the plug from the valve seat While reversing the direction of rotation of said holding means, said work piece holder being centered by the plug held by said plug holding means.

2. in a machine as in claim 1, saio. rotating means comprising a drive shaft. a pair of spaced disks mounted upon said shaft, a spindle conuected to said holding means, and means for` alternately clutching each disk of said pair with said spindle.

3. In a machine as in claim 2, said clutching means further comprising a pair of springs for urging each of said pair of disks into contact with said spindle, and cam means for moving said disks against said springs.

4. In a machine as in claim 3, each disk having one face of larger diameter than the opposite face forming a circumferential flange, and an oil collecting groove at the base of said ange.

5. In a machine as in claim 4, each disk being composed of cast iron, and friction increasing copper inserts in the spindle contacting face of each disk.

6. In a machine as in claim 1, said work piece holder comprising, a pair of superimposed plates mounted upon said base plate for relative movement parallel to said base plate and crosswise with respect to each other, and a workpiece gripping plate vertically inclinably mounted upon said pair of plates.

7. A self-centering workpiece support comprising a base plate, a rst plate, means mounting said base plate for linear movement upon said base plate, a second plate, means mounting said second plate upon said rst plate with movement perpendicular to the movement of said rst plate upon said base plate, a workpiece gripping plate, and universal movement means for mounting said gripping plate upon said second plate.

WILHELM BEER.

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

UNITED STATES PATENTS Number Name Date 223,507 Hayden Jan. 13, 1880 944,845 Burns Dec. 28, 1909 1,428,269 Sorby Sept. 6, 1922 1,893,637 Rogers Jan. 10, 1933 1,951,080 Bartos Mar. 13, 1934

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