US1964970A - Valve seat tool - Google Patents

Description

y 3, 1934 F. o. ALBERTSON 1,964,970

VALVE SEAT TOOL Filed Oct. 3, 1932 Patented July 3, 1934 UNIED STATES VALVE SEAT TOOL Frans 0. Albertson, Sioux City, Iowa, assignor to Albertson & Company, Inc., Sioux City, Iowa,

a corporation of Iowa Application October 3, 1932, Serial No. 635,972

1 Claim.' (01. 7758) The present invention relates to valve seat tools and is particularly concerned with tools for cutting recesses in valve seats for the insertion of a new valve seat or valve seat ring.

5 The present application is a continuation in part of my prior application, Serial No. 340,770, for Valve seat reconstruction tools, filed February 18, 1929, and of my prior application, Serial No. 536,520, filed May 11, 1931, for Valve seat tools.

The present application relates particularly to an improved commercial form of the cutting tools shown in said parent application, and the present application is substituted for the second of said applications mentioned above.

The present invention is of particular importance in connection with the reconstruction of valve seats for internal combustion engines, since it is peculiarly adapted to form an annular recess for the reception of a new valve seat ring to reconstruct the valve seat or to furnish the engine block with a seat of harder material, but the tool is also of general'application to circular cutting operations of all kinds.

One of the objects of the invention is the provision of an improved cutter capable of cutting an annular recess in a valve seat for the reception of a new valve seat ring.

Another object of the invention is the provision of a cutting tool of the class described having an improved structure and an improved mode of securing the cutter blade in'the cutter body.

Another object is the provision of an improved valve seat cutter structure by means of which a cutter of higher quality may be made at a lower cost, thereby placing tools of the best quality within the means of a vast number of purchasers.

Another object is the provision of an improved commercial form of the ring recess cutter shown 40 in my prior applications in which the cutter blade is more permanently secured in its supporting body. The cutters disclosed in my prior application were disposed in a milled slot, the walls of the slot clamping the cutter by virtue of the driving of a pin into an adjacent slot. Considerable trouble was encountered with cutters of that particular construction on account of the tendency of the cutter to move, particularly in the small sizes of cutters where the milled slots are close to the hole in the middle of the cutter body. In such case, the metal between the milled slots and the tapered hole was not sufficient to secure the cutter firmly.

Another object of the invention is the provision of an improved cutter of the type disclosed in my prior application which does not depend upon pressure solely to hold the cutter and in which the cutter is securely locked by a perma-, nent inter-locking auxiliary device.

Other objects and advantages will be apparent from the following description and from the accompanying drawing in which similar characters of reference indicate similar parts throughout the several views. g

Referring to the single sheet of drawing:

Fig. 1 is an elevational view in partial section, showing the application of the present cutter to a valve seat in cutting an annular recess; Fig. 2 is anexploded view in perspective of the cutter body, blade and securing pins, showing 71) the shape and arrangement of these parts;

Fig. 3 is a full size fragmentary elevation of the cutter, showing the shape and. arrangement of the assembled cutter;

Fig. 4 is a sectional view taken on the plane 75 of the line 4-4 in Fig. 3, showing the mode of securement of the blade; p v

Fig. 5 is a sectional view taken on the plane of the line 55 in Fig. 4, looking in the direction of the arrows, showing the mode of securementof 30 the blade; and. M

.Fig. 6 is a sectional view taken on the plane of the line 6-6 ofFig. 3, showing a bottom plan view of the cutting tool. I

Referring to Fig. 1, this is an elevational view of the complete valve tool assembly comprising a pilot stem 10, a cutter. 11, and a tool holder 12. The assembly is shown in connection with an internal combustion engine block 13, having a valve stem guide 15, and having a valve seat which has been cut away to form the annular groove 14. The pilot stem 10 may consist of 'an expanding type of pilot or any pilot which is adapted to be fixedly secured in the valve stem guide 15.

The pilot preferably consists of an integral metal member formed of tool steel, having an upper cylindrical portion 9, which is adapted to slidably and rotatably receive the tool ho1der12.

Thetool holder 12 is provided with an accurately machined bore 16 for receiving the cylindrical end 9 of the pilot stem. The pilot stem 10 is also preferably provided with a lower cylindrical portion 17 conforming in size very closely to the size of the bore 18 in the valve stem guide 15. V

The pilot stem 10 is also provided with a very gradually tapered portion 19 which is adapted to be forced into wedging engagement with the up?- per portion of the valve stem guide 15 at the end of the guide where the guide is apt to be enlarged no due to the wabbling of the valve stem. The taper n the pilot stem is so gradual that it cannot be discerned with the naked eye and is exaggerated for the purpose of illustration in Fig. 1. This taper is preferably about twenty-two thousandths of an inch per foot, or within the range of from fifteen thousandths of an inch taper per foot to three thousandths of an inch taper per foot. The tapered portion 19 on the pilot stem preferably comprises only about one-third of the lower part of the pilot stern, being sufficient to engage only the upper portion of the valve stem guide 15 and giving suflicient area of wedging contact to closely secure the pilot stem in the valve stem guide 15.

The tapered portion 19 is not intended to center the pilot, but merely to secure it in place, and the actual centering of the pilot is accomplished by the lower cylindrical portion 1'1, which is adapted to fit the cylindrical bore 18 in the guide very accurately.

Particular attention is directed to the fact that the taper of the pilot does not extend the full length of the lower part of the pilot, as this would provide considerable clearance between the lower end of the pilot and the bore 18 and tend to cause the pilot to line up with one side or the other of the guide. It is found that the most accurate results can be secured by having the lower portion 1'? conform as nearly as possible to the actual size of the bore 13 in the valve stem guide 15, so as to effect a very close fit between the cylindrical portion 17 and the bore 18. The most accurately cylindrical part of the guide, which will later guide the valve stem, is the middle portion of the guide between the ends, because the ends of the guide 15 are apt to be rounded off inside the bore 18. The pilot should, therefore, fit the cylindrical portion of the bore 18 midway between the ends of the guide.

In order to accomplish this result the pilot stems are provided in sets ranging in various size which differ only by one thousandth of an inch in diameter and it will be evident that the function of the tapered portion 19 is merely to effect a wedging engagement between the pilot stem 10 and the guide 15, the actual centering function being performed by the closely fitting cylindrical portion 1'7 which engages the major portion of the middle of the guide 15.

The tool holder 12 consists of a substantially cylindrical metal body which may be provided with a tapered portion 20 adapted to be received in the tapered bore 21 of the cutter body 11. The cutter 11 is fixedly secured on tool holder 12 by the frictional engagement of the tapered portion 20 in the bore 21. The tool holder 12 is provided with an aperture or transverse bore 22 adjacent its upper end for receiving the pin or rod which may be used as a handle and preferably with a noncircular portion 23 for receiving a wrench or other force applying tool.

The cutter or cutting tool 11 preferably consists of a substantially cylindrical metal body of tool steel which may be provided with an upper fiat surface 25 and an outer cylindrical surface 2%. The upper flat surface 25 is adapted to engage a thrust bearing or feeding member, as disclosed in my prior parent application, above mentioned, order to force the cutter downwardly into a valve seat. The body of the cutter 11 is provided with an axially extending slot 26 located in one of its sides and adapted to receive a cutter blade 30. The slot 26 is preferably provided with substantially plane walls 2'7, 28, 29, forming a slot substantially rectangular in section and adapted to receive the cutter blade 30 of complementary cross sectional shape.

The cutter blade 30 preferably comprises a member formed of the best alloy tool steel, having a cross sectional shape spaced complementary to the shape of the slot 26, except at its lower end, where it is provided with a laterally projecting lug or heel 31.

The heel 31 forms a shoulder 32 which engages the lower part of the cutter body, as shown in Fig. 5. The cutter body is also preferably provided with a transversely extending slot 36 located in the lower fiat surface 37 of the body and extending across the end of the slot 26. This leaves the downwardly projecting lug 38 on the bottom of the body, and the lug 38 is adapted to be located in front of the lug 31 on the blade 30 when the parts are assembled. The blade 30 must, therefore, be slid into the slot 36 from the bottom, with its lug 31 located behind lug 38 and lug 31 fitting in the slot 36.

Of course, the cutter blade 30 is so proportioned as to be a close frictional fit in the slot 26, to aid in its securement, but in order to secure it more firmly and prevent any possibility of loosening of the blade, which would change the size of the recess 14 cut by the blade, the blade is also preferably secured by means of positive securing devices, such as transverse pins 39, 40. The cutter body is preferably provided with another axially extending slot 41 which is substantially triangular in section, being so arranged as to provide a fiat surface 42 transversely to the direction in which the pins 39 and 1 are intended to extend. fiat surface 42 may th n be used to drill bores e3 for the pins 39 and after the cu ter has been put in place, and a pair of steel pins 39, 40 may be driven into close frictional it in the bores 43 to secure the cutter permanently in the slot 26. The pins 39, 49 not only prevent the blade from tilting in the cutter body, but they hold it in position with the inter-locking lug 31 secured in the slot 36 behind the lug 38. There is no possibility whatever of the cutter loosening and changing the angular shape of the recess 14, and the trouble caused by loose blades in the devices of the prior art is entirely eliminated.

The blade 30 is preferably provided with an axially extending cutting edge 33 which is parallel to the axis of the tapered bore 21, tool holder 5, and pilot stem 10. The cutting edge 3% at the lower end of the blade 30 extends at substantially right angles to said axis. Each of the cutting edges 33, 34 is preferably provided with sloping surfaces 35, 15 on the blade 30, sloping backward from the cutting edge so as to provide relief or clearance between the surface of the metal cut and the remainder of the blade. In some cases the cutting edges 33, 34 may be so formed as to under-cut the angular groove 14 to retain the valve seat ring more firmly in the groove 14 and any desired shape of recess can be cut by changing the shape of the cutting edges.

The cutter body and blade are preferably finished off to cylindrical form at the outer surface 46 of the blade, the ends of the pins also being ground oif flush with the body. The cutter body may be made of lesser diameter at the lower part 47, but the upper part is preferably adaped to extend out flush with the outer surface 46 of the blade in order to support the blade firmly at its outer edge and prevent any chattering.

The method of manufacture of the cutting tool is as follows:

The supporting body is first formed to substantially the shape shown, and provided with the tapered bore for receiving the tool holder. The triangular slot 41 and rectangular slot 26 may then be formed, and the inter-locking slot 36 may then be formed in the walls of the cutter body. The blade may then be formed to substantially the shape desired and driven into the slot 26 from the lower end of the slot until lug 31 inter-locks behind lug 38 in the slot 36.

The bores 43 for the securing pins may then be drilled through the cutter body and blade simul taneously, and the pins 39, 40 driven into place. The projecting ends of the pins are then ground oif and the blade is mounted on a tool holder which extends through the tapered bore 21. The cutting edges 33, 34 of the blade are then sharpened or ground with respect to the axis of the tool holder so that they are adapted to cut a recess 14 which is accurately concentric with respect to the tool holder 12 and pilot 10. If desired, the angle between cutting edges 33, 34 at the point 48 may be made slightly acute for the purpose of eifecting a cleaner cut in the corner where the blade is more apt to wear off.

The cutter 11 is utilized as shown in Fig. 1, where it is rotatably supported on the tool holder 12, which slides and rotates on the pilot stem 10. The pilot stem 10 is accurately centered in the valve guide 15 by its cylindrical portion 17 and fixed in the valve guide 15 by the tapered wedging portion 19 which engages in the upper part of the valve stem guide 15.

When the cutter 11 is rotated and forced downward by an appropriate fixture or by pressure on the top with the feed screw, an annular groove 14 is cut in the valve seat, and a new ring may then be inserted, the ring being of harder metal or alloy metals more perfectly adapted to form a valve seat than is the metal of which the engine block 13 is formed.

It will thus be observed that I have invented a new valve seat cutter 11 which is peculiarly adapted to be used in the reconstruction of valve seats, as well as a new cutter assembly peculiarly adapted to form the recesses desiredfor the insertion of new valve seat rings. The present cutter is capable of performing its work very efficiently and may be manufactured at a very low cost.

The present cutter also has its blade so firmly interlocked in the cutter body and secured by means of the transverse pins that there is absolutely no possibility of the blade getting out of alignment with respect to the axis of the tapered bore 21 which also corresponds to the axis of tool holder 12 and pilot 10.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claim.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States, is:

A cutting tool comprising a substantially cylindrical metal body, said metal body having an axially extending slot, a cutter blade fitting in said slot and having cutting edges projecting beyond said body, said body having another axial slot spaced from the first-mentioned slot and having its wall substantially parallel to said blade, said body having a pair of bores extending from said wall through said body and blade, and a pair of metal pins driven through said body and blade to permanently secure said blade in said body, said blade having a laterally projecting lug and said body having a groove in its lower surface, said lug engaging in said groove to secure said blade in predetermined position in said body.

FRANS 0. ALBERTSON.

Images