US1786023A - Valve-centering device - Google Patents

Description

Dec p23, 1930. H. G. MILLER 1,786,023 I VALVE CENTERING DEVICE Filed April 27, 1927 INVENTOR. Ham/ 51 Mu 00 404 A TTORNEYS.

Patented Dec. 23, 1930 UNITED STATES HARRY G. LIILLER, OF DENVER, COLORADO VALVE-CENTERING DEVICE 7 Application filed April 27,

This inventionrelates to improvements in stem centering means for valve grinding machines and has particular reference to means closed a carriage for stemmed valves provided with a tail stock centering pin and an intermediate steady rest adapted to co-operate in centering thevalve stem independently of the valve the latter .beingengaged by a driving head primarily for the purpose of rotating it about the axis of the stem. In the practical use of suchmachines, it has been found that valve, stems frequently have irregularities of surface contour due in some cases to original defects, in other cases to wear, and in other cases to an accumulation of carbon, and where such irregularities register with the steady rest, it is obvious that defective alignment or eccentricity in rotation will result. The steady rest is necessarily located in proximity to the valve and therefore such irregularities interfere materially with the accomplishment ofthe de sired purpose of grinding the valve true to the axis of its stem.

It has also been found difficult to; avoid movement of the valve stem with reference to the steady rest, thereby permitting a vibratory or chattering movement of the valve or a displacement of the valve and the associated end portion of the stem under frictional pressures exerted on the face of the valve by the abrading tool or grinding wheel.

The primary ob ect of my invention is to provide means for supportlng valves true to the axes of their stems while such valves and stems are being rotated during a grinding operation regardless of whether the valve stems are carbon1zed,-worn, or otherw se provided with surface irregularities or eccentric depressions.

More particularly stated, the object ofthis invention-is to provide a sleeve mounting into which the valve stem may beinserted in. such a manner that the axis o-f the stem and mount- 1927. Serial No. 186,952.

ing will coincide,the mounting being provided with a cylindrical surface truly concentric to the axis of the stem and journalled in a bearing member adapted for anchoring engagement with the steady rest, whereby the valve stem and its sleeve mounting may be rotated in such bearing during a valve grinding operation, thereby insuring a grinding of the valve true to the axis of the mounting and, therefore, also true to the axis of the stem.

In the drawings Figure 1 shows a fragment of a grinding machine carriage provided with head and tail stock members and an intermediate steady rest, all similar to the corresponding parts disclosed in said former application but with the valve stem supported in the improved mounting forming the subject matter of this application.

Figure 2 is a cross sectional View drawn on line 22 of Figure 1.

Figure 3 is a longitudinal sectional view of the mounting drawn on a plane intersecting the oil cup of the anchoring bearing member and the set screw for securing the mounting rigidly to the valve stem preparatory to the grinding operation, a fragment of the steady rest being also illustrated in section, and a tappet valve being illustrated in full.

Like parts are identified by the said reference characters throughout the several views. A hearing sleeve 10 having an outwardly turned end flange 11 is journalled in a bearing member 12, one end of which abuts the flange 11 and the other end of which is provided with a cylindrically enlarged portion 13 having a conically tapered undercut shoulder 1e adapted to receive the correspondingly tapered surface 15 of a semi-cylindrical steady rest socket member 16 supported from the carriage rod 17 by the bracket. arm 18 shown in Figure l. The oil cup 19 is. preferably employed to feed lubricant into; the

longitudinal channel 20 formed in the outer surface of the bearin sleeve 10 as clearly shown in Figure 3. g

The lubricant in the channel 20 also lubri- G t s the n l h t be ring of he l e 23 against-the portion 13 of-the. bearing meniher 12. Therefore, the sleeve 23 has little tendency to rotate the bearing member 12 and the anchorage of the conical projection 15 is effective to hold the bearing member against rotation being in substantially cone clutch engagement therewith by reason of entry of the projection 15 in the conically tapered groove 1 1.

A. co-operating valve stem mounting sleeve 22 is secured to the bearing sleeve 10 by a coupling sleeve 23. A set screw 2st connects the coupling sleeve with the mounting sleeve 22 and this set screw is also utilized to lock the valve stem 25 in the mounting preparatory to the grinding operation.

The object of forming the mounting sleeves 10 and 22 in two parts instead of one is to facilitate tempering them without the distortion which might result from tempering a tube aaving a length equal to the combined length of the sleeves 10 and 22.

The forward end 27 of the coupling sleeve abuts the portion 13 of the anchoringbearing member 12 when the parts are assembled in the carriage preparatory to a grinding operation. The tail stock centering pin 28 is provided with a centering cup 29 having a conically tapered socket to receive the tapered end 3O the mounting sleeve 22. The outer end of the centering pin 28 is provided with a cam 32 adapted to bear against the tail stock head 33 to retract the centering pin, said pin being normally urged inwardly by spring 341 in the ordinary manner.

In preparation for grinding a valve the stem 25 will first be inserted in the bearing sleeve and rotated therein whenever deposits of carbon or other projecting material tend to interfere with the movement of the stem through this sleeve. In this manner deposits of carbon such as accumulate upon the stems of internal combustion engine valves near the valve heads may be utilized to fill depressions and insure a tight fit of this portion of the stem within the sleeve 10. Thereupon the mounting sleeve 22 will also be applied to the stem, the coupling sleeve serving to properly align the two sleeves 10 and 22 and the set screw 24. being then turned up to securely anchor the mounting sleeve to the valve stem, whereupon the outer or left hand end of the sleeve 22 may be engaged in the tail stock centering cup 29 and the centering pin 28 pushed backwardly until the portion 13 of the bearing 12 can be brought into a position for engagement with the conically tapered end of the steady rest socket member 16. The anchorage obtained by the surface 15 of the steady rest in the conically undercut groove 14; of the portion 13 of the bearing securely anchors this hearing to the steady rest so that the bearing becomes temporarily a part of the steady rest within which the valve stem and its bearing sleeve 10 may rotate. The

pressure of the tail stock spring 34: brings the forward end of the coupling sleeve 23 into thrust bearing contact with the portion 13 ol the bearing member 12, thereby holding this portion in anchoring relation to the steady rest socket member 16, all. other parts or the mounting being free to rotate when the valve is being rotated in contact with the grinding wheel by the driving head 36, the latter ha ving a work engaging chuck 37, which, for the purpose of this description, may be assumed to be of any ordinary construction.

The set screw 24 may be utilized to permit an adjustment of the mounting relatively to the valve stem so as to ensure that the valve is in proper position to be engaged by the driving head and a slight permissible separation of the end 27 of the coupling sleeve 23 from the portion 13 of the non-rotatable hearing member 12 will allow the spring 34 to press the valve resiliently against the driving head. This or any other sliding interlocking connection of the non-rotatable hearing member with the steady rest will allow the valve to be pushed against the driving head with the desired pressure.

I claim:

1. In a grinding machine carriage provided with head and tail stock members for engaging stemmed valves, a centering mounting for the valve stems provided with a nonrotative bearing member near one end in which such mounting is journalled, said hearing member having means for manipulative anchoring engagement with a steady rest on the carriage; in combination with a steady rest adapted to permit free removal of the bearing member when the latter is in a position of manual adjustment relative to the steady rest.

2. In a grinding machine carriage provided with head and tail stock members for engaging stemmed valves, a centering mounting for the valve stems provided with a nonrotative bearing member near one end in which such mounting is journalled, said bearing member having means for anchoring engagement with a steady rest on the ca rriage said mounting having a portion for engagement with a tail stock centering pin and another portion adapted for thrust beau ing engagement with the non-rotative bean ing member.

3. A centering mounting for valve stems comprising a stem support in which a valve stem may be centered and secured and a bearing in which the stem support may rotate, said bearing having means for anchorin engagement with an open steady rest.

4. A centering mounting for valve stems comprising a stem support in which a valve stem may be centered and secured and a bear ing in which the stem support may rotate, said bearing having means for anchoring engagement with an open steady rest, and said stem. support being adapted for engagement with a tail stock centering pin, and of a length to span the space between said pin and the steady rest, whereby said pin may hold the bearing in said interlocking anchoring engagenient.

5. The combination with the carriage of a valve grinding machine, of a centering mounting for valve stems, comprising a valve stem holder )rovided with a cylindrical bear ing surface concentric: to the axis of the stem to be engaged by the holder wheniproperly secured therein, a bearing sleeve in which one end of the holder is journaled, and a steady rest having a relatively fixed open bearing for the bearing sleeve, said sleeve and steady rest being formed for manipulative interlocking engagement to prevent the sleeve from moving out of the steady rest on the open side.

6. The combination with the carriage 01" a valve grinding machine, of a centering mounting for valve stems, comprising a valve stem holder provided with a cylindrical hearing surface concentric to the axis of the stem to be engaged by the holder when properly secured therein, a bearing sleeve embracing said cylindrical bearing surface and shouldered for interlocking thrust bearing engagement with a relatively fixed support, a rela tively fixed steady rest having an'open hearing to receive said sleeve, and against which said sleeve shoulder may have thrust engagement, and a. resiliently mounted tail stock centering pin formed to engage the outer end of the holder to center the latter in co-operation with said steady rest, and to press the same into thrust bearing relation to the end of the sleeve, said sleeve being formed to utilize said pressure to anchor it to the steady rest.

7. The combination with a valve grinding machine carriage having a head stock, tail stock, and an intermediate open steady rest, of a mounting for valve stems adapted to hold the stem with its axis coinciding with that of the mounting, means carried by the tail stool; for centering the mounting upon said axis at its outer end, and means carried by the steady rest for centering the inner end portion of the mounting, and holding it to such centered position during rotation of the mounting in a valve grinding operation.

8. The combination with a valve grinding machine carriage having a head stock, a tail stock, and an intermediate open steady rest, of a cylindrical mounting within which valve stems may be anchored with their axes coincident with the axis of the mounting, a bearing sleeve for one end portion of the mounting adapted to be received in the open st ady rest, and means for anchoring the sleeve to the steady rest by thrustengagement with one side of the latter, said mounting being adapted to receive thrust from the tail stock centering means, and to transm t HARRY G. MILLER.

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