US1882692A - Method of making valve seat finishing tools - Google Patents

Description

Oc 18, 3 F. o. ALBERTSON METHOD OF MAKING VALVE SEAT FINISHING TOOLS Original Filed N0v.18, 1929 3 Sheets-Sheet l Oct. 18, 1932. ALBERTSQN 1,882,692

METHOD OF MAKING VALVE SEAT FINISHING TOOLS ori inal Filed x0 18, 1929 s Sheets-Sheet 2 llllllll fraiz' aazerzsm' @m W4WM 422,75.

Oct. 18, 1932. F. o. ALBERTSON unmon OF MAKING VALVE SEAT FINISHING TOOLS Original Filed Nov.18, 1929 S Sheets-Sheet 3 I 12, warn/Z571 jmzzs Q filerzfim Patented Oct. 18, 1932 UNITED STATES-"- Farms 0. ALBERTsoN oF 'srotrx cr'rmaowansslonon 'ro ALBER'rsoN & comrm,

me, or SIOUXCITIIOWA,

A GORIEORA'I'ION OF .IOWA

Mm'nonor' MAKING "VALVE SEAT rrivrsnmo 'rooLs Original app1ication.fi1ed November 18, 1929, Serial No. 107,877. Divided and thisiappl icatlon filed September 4, 1930.

The present case is a division of applicants co-pending application, Serial No. 407,877,

filed November 18, 1929. t v

In the finishing or reseating of the valves of internal combustion engines, the reamers or other tools of the priorart have not been capable of forming a perfectly finishedva'lve I seat, and it has always been necessary to usea lapping or grinding operation in order to attain the degree of perfection which isdesirabie for modern internal combustion engines. This grinding or lapping operation is usually performed with the valve in place, by putting a small amount of grinding compound. on the seat or valve. and by oscillating the valve upon its axis with the valve-engaging the seat, and the grinding of the valve on the seat is relied uponto secure a perfect fit between the valve and the seat in the devices of the prior art. I The reason for such lapping or grinding operation was that it was practicallyjimpossible for the prior reamers to finish a I valve seat with a uniformly perfect seating surface and a close examinationand test of the valve seats made by the too'ls ofthe prior art shows that there are numerous, waves in the surface of the valve seat, consisting of minute hills and valleys, generally extending radially with respeetto the axis of the valve and seat. v

One of the most important factors con-' tributingto this lack of perfection of the valve seats made by the prior tools was the tendency of the reamer to chatter, instead of cutting evenly and smoothly,and those skilled in the art have sought for many years to 50 avoid the chattering of the reamer, generproducing tools having a greater degree of em or; the like, by means. of which reamers of superlative quality'and operating characteristics can, be produced: in quantity at a minimum cost, i

undesirable factors of chattering or'uneven Serial No. 47 9.590-

ally by varying the number of teeth used and by using anodd number of teeth.

' 'jNone-of'the devices of the prior'arthave art always consisted of at least a two-step method, thelast stepbeing the lapping in of the valve with the valve grinding compound and a machine for oscillating the valve. V r I One of the objects of the present invention is the. provision of ,an' improved one-step IllfitllQClOf finishing valve seats, by means of which the customary grinding or lapping operation may be eliminated. I Y r Another object is the provision of an improved valve seat reamer or valve reconstruction tool which is capable of producing a substantiallyperfect valve seat surface.

Another object, isthe provision of an improved method of manufacture of valve reamers. and similar tools, which is capable of perfection and having novel and advantageous operating characteristics.

Another object is the provision of an improved. method of manufacture of valve ream- Another object is the elimination of the cutting which were present .in the reamers" of the priorart, and theprovisionof an improved reamer capable of producing a more perfect finish n pon a valve seat.

Other ob'elcts and ad antages of the inven-. tion will be apparent. from the following description and from the accompanying'dra'w- V ings, in which similar characters of reference indicate similar parts throughout "the several views.-

Referring to the drawings,of which there are three sheets; o f

Fig. ,1 is an elevational'view inlpartial sectionfillustrating the mode of use of the reamer and the one-step method 0f finishing loo to distinguish with the naked eye, the views 'of Figs. 4, and 6 have been drawn on a "of'the same reamer;

valve seats, the reamer illustrated being a 45 reamer;

Fig. 2 is an elevational view of a 30 reamer of the type shown in Fig. l; r

Fig. 3 is a similar view of a 60 reamer;

Fig. 4 is an enlarged elevational view of the reamer of Fig. 1;

Fig. 5 is an enlarged bottom plan view I Fig. 6 is an enlarged sectional view taken on the plane of the line 66 of Fig.5;

Fig. 7 is a development of the periphery ofthe same reamer;

Fig. 8 is a diagrammatic view of the ap paratus used in the formation of the reamer teeth; and

Fig. 9 is a diagrammatic view of the apparatus used in the sharpening of the reamer teeth.

Referring to Figs. 4 to 7, I shall first describe the structure and characteristics of the improved reamers made according to the present invention, but since the improved features and characteristics of the teeth are diflicult scale three times the size of the reamer.

may be secured upon a tool holder 13 by the frictional fit of a complementary tapered por- :tion 14' in the tapered bore 12.

' The body. of the reamer is cut away at regular intervals around "the lower and outer edge of the reamer, with a plurality of cuts, preferably of triangular section, forming substantially flat walls 15 and 16 on each side of the cut, forming the teeth 17 provided with cutting edges 18. The cuts which form the walls 15 and 16 are made diagonally with respect to a certain axis on the reamer, so that the teeth 17 thus formed, extend substantially along the angle of the reamer desired.

Thus, fora 45 reamer, the general direction of the feed against the cutting tool would 7 "be at45 to the axis of rotation of the reamer iblankwhich 'is being cut, were it not for the fact that a reamer is provided with the same number of teeth at the top and the bottom, and the frusto-c'onical surface of the blank having a larger diameter at the top, 'it" is desirable that the pitch of the tooth beiincreased to correspond with the larger diameter. --".0

In making reamers of the type illustrated, it will be observedthat the fiat or slightly. concave surface .37 formed by the sharpening operation, is of substantially the same width across the tooth, thereby decreasing the amount of material which must be ground cutting edges of the reamers of the prfe away in the sharpening operation, below that which would be the case if a 45 reamer, for example, were cut with a 45 feed. A 45 feed would make the cuts of similar width from the bottom to the'top of the reamer, and since the top frusto-conical surface of the reamer blank has a greater diameter, the teeth 17 would be very wide adjacent the outer edge 'of the reamer. I

The exact angle at which the dividing 1 sad should beset, and consequently the angle of feed for any milling cutter, any given number ofteeth and any degree of reamer, may beyascertained from standard tables of the angles of elevation for milling teeth in blanks of various degrees. For instance, the angle of elevation for milling teeth in a 45 blank having fifteen teeth, with a 60 fluting cutter, is 32 and the axis of rotation of the reamer blank should preferably be set at this angle to form a reamer as disclosed in the application.- It should be noted that this angular setting is not intended to affect the location of the cutting edge, but rather to affect the location of the rear Wall of the tooth.

Reamers may be made of any angularity, two other examples of which, and 60 have been illustrated in Figs. 2 and 3, and the conventional setting for forming teeth of increasing pitch on reamers of any angularity,

may be determined from standard tables.

The ordinary commercial sizes of reamers are 15, 30, and but it will be understood that any desirable size of reamer may be constructed.

It should also be understood that the exact shape of'the cuts produced by the cutting tool depend upon the type of tool employed, and the provision of substantially flat sides on, theteeth 17 is incidental to the cutting of reamers with milling tools.

One of the most important features of the present invention is the direction in which cuttlng edges 18 extend with respect to the true axis of the reamer. The true axis is indicated by the numeral 19 and an eccentric axis upon the horizontal base line 20 is indicated by the numeral 21.

It has alrea'dy bee'n pointed out that produce minute irregularities such as h is and dales, extending radially of the surface of the valve seat, and it will be-evident that the radial teeth of the reamers of the prior art would naturally fall into such valleys or da-les between successivehigh points, thereby accentuating the undesirable result when it has once begun.

The cutting ed es of the reamers constructed according to the present invention, do not all extend radially at the same angle to the axis of the reamer as in the devices of the prior art, but the various teeth, or certain of them, extend at substantially different angles to each other and'to theaxis of thereamcr.

I and the cuttingedges is so minute that it chattering effect would be accentuated with;

further undesirableresults. Assuming that the present valve tool was employed upon a. seat which had such a radially extending irregularity, if one of the teeth happened to fit this irregularity in alignment, the. next tooth would be at a diflerent angle, so that it would straddle the valley and also produce some shearing effect on the seat during'the 1 cutting operation. Thus, each of the cutting edges of the present reamer is preferably disposed at a slightly different angle, but the amount of divergence between a radial line cannot be distinguished by the naked eye alone.

In the present embodiment of the lnvention, which representsa form most conveniently and economically manufactured, the cutting edge 22 extends radially with respect to the true axis 19 of the reamer, but at substantially 45 to: said axis in a 45 reamer.v Since the same principles may be applied to reamers of any angle, it is only necessary to describe the 45 reamer, and the term radially is used in the generic sense to include all of the lines in any radial plane, that is, a plane which includes the axis of the reamer. All of the other cutting edges .23 to 35, inclusive, extend along lines drawn to the point 21 which'is spaced slightly from the truecenter 19.

It will thus be observed that all of the cutting edges extend substantially along'lines which are radial with respect to the eccentric point or axis 21, and consequently the angle between the cutting edges and a true radial or plane, increases by steps from the edge 23 to the edge 29, and decreases by steps from the edge 30 to the edge 36, the divergence between the cutting edge 22 and theradial line being theoretically equal to zero.

Each of the teeth 17 is provided with a slightly fiat or coucavely curved surface 37, which is formed by the sharpening operation, and the juncture of the surfaces 27 and 16 on the various teeth, forms the cutting edges 22 to 36, inclusive. The particular form of teeth illustrated and described, is the result of the method of manufacture which will now be described in detail.

The exact location and direction of the teeth is diflicult to determine on account of cutting edges of the the minute measurements required and the complexityof the geometrical problems involved in specifying the exact direction, but .the foregoing description hasbeen provided in order to ive one accepted theory of the operation of the present tool in forming a perfectlyfinished valve seat.

It is found that tools constructed according to the method described hereinafter have cutting edges of varying angularity best illustrated in Fig. 7, which is a panoramic, imaginary View of'the side of the reamer. he angularity of the teeth varies, not only with respect to radial lines drawn from the axis of the reamer, but certain of the teeth varyby a very slight degree from the 45 angledesired on the valve seat, as, for instance, in Fig. 9 thetooth 33 happens to be at an angle of 44 58 to the horizontal, While the tooth 26 is at an angle of 45? 2' to the'horizontal as indicated. 1

This result is thought to be due to the clearance which is provided for thecutting edge during the grinding or sharpening operation, and another theory of operation of the present cutting edges is that the reamer .is provided with one edge or tooth extending truly at an angle of 45, whereas the other teeth not only diverge laterally from radial lines, but also diverge upward or downward from the true 45, tending to cut deeper at one end and shallower at the other end, but

the composite result of the entire set of teeth is known to be'a practically perfect 45 valve seat.

' The method of manufacture of the presentreamers is as follows. A "blank of the best tool steel is provided, having the usual shape, and the tapered bore 12 adapted to receive a spindle carried by the reamer cutting machine. The reamer cutting machine is illustrated in detail in my co-pending application, Serial No. 414,- 392, filed December 16, 1929, for reamer cutting machines, but the apparatus is also illustrated diagrammatically in Figs. 8 and 9. Thus the valve reamer cutting machine may consist of a milling machine having a spindle 38 which is provided with an eccentric tapered portion 39 adapted to be 'received in the bore 12 of the reamer blank. The eccentricity of the tapered portion 39 with respect to the spindle 38 is equal to the distance between the points 19 and 21 in Fig.

5, and the spindle 38 is adapted to support "the blank during the cutting operation and sup- '5 but the variations in elevation of the dividing head and the eccentricity of the spindle vary the spacing depth and angularity of the teeth formed, as described hereinafter.

The reamer cutting machine is provided with some means for raising and lowering the spindle 38 to regulate the depth of cut of a milling cutter 40 and with means for securing the blank in any of'therespective positions to which it may be moved step by step. The cutting machine is also provided with the milling cutter 40 supported upona shaft 41 which is movably mounted so as to feed the milling cutter 40 into the blank along a line at the proper angle to the spindle 38 for making a 45 reamer, as determined by standard tables of the settings for cutting teeth on blanks with milling cutters.

The method of operation of the machine is, in brief, as follows: A reamer body is supported upon the eccentric portion 39- of spindle 38 and with the reamer held in fixed position, the milling cutter 40 is advanced through the lower and outer edge of the reamer to produce a cut havingthe walls and 16 of Fig. 5. The milling cutter is then withdrawn, the reamer body rotated on its eccentric axis one step to the position for the male ing of the next cut, and at. the same time the elevation of the spindle S8 with respectto the milling cutter maybe adjusted to any desired amount.

In the ream-er cutting machine of the above mentioned application, automatic means is provided for raising and lowering the reamer between the cutting operations, so that the respective cuts may be made to give cutting ed "es of substantially the same length in the 1:: finished reamer. It should be observed that in Fig. 5, the cuts made at-theleft-hand side forming the teeth 36, 22 and 23, for example, are not of as great depth as the cuts made on the right-hand side to form the teeth 29 and 30, for example. If the same elevation ofthe reamer were employed to make cuts at both of the sides of the reamer, the cuts made adj a cent the edge 22 would be much deeper than the cuts made adjacent the edges 29 and 30, because the eccentricityof the spindle portion 39 also serves to elevate and lower the reamer by an amount equal to the amount'of eccentricity.

It is also noted'that the variation in depth of cut produces the spacing of the cutting edges since the cut made is substantially triangular in section, and the deeper cut defines a triangle having its outer corners spaced farther from each other, the outer corners.

being the cutting edges. An infinite number of different arrangements of the spacing of the teeth may be made, and the spacing illustratedin Fig. 6 is to be regarded as exemplary of but one form ofthe invention. The result of this cutting operation is areamer which has teeth 17 with edges extending along lines converging in a the eccentric axis 21, so that all of the edges on by the removal of some of the material behind the cutting edges 2236. For this purpose, the shafts 44 and 42 have their axes disposed in pairallel'planes, but the grinding wheel axis 44 is slightly below the plane of the shaft 42.

The reamer grindin machine maybe of the usual form provided with a stop'or other device for holding the reamer in proper position to grind each tooth, and the grinding wheel'43 is preferably rotated in such a direction as to proceed against the cutting edge of the tooth and away from the clearance edge ofthe tooth, as shown in Fig. 9.

Since the reamers are ground with a grinding device which would ordinarily produce a frust-o-conical surface if other portions of the 'reamer had not been cut away, the flat surfaces 37 adjacent the cutting'edges are substantially portions of a frusto-conical surface, but not exactly so, on account of the slight amount of clearance which is generally desirable; The cutting edges 25 may then be described as substantially lines extending along an imaginary frusto-conical surface, and these are lines which are produced by a cut through a frusto-conical surface so that the cutting edges of the teeth approximate lines geometrically known as conic sections. Such lines are slightly curved, the curvature depending upon the plane through which the conicsection is made,-and each one of the teeth represents a conic section taken at a slightly different angle.

The exact form of reamer cutting machine used is described in detail in the above mentioned application, to which reference may be made for a more complete understanding of the apparatus required, but since the present method might be carried out upon many different forms of apparatus, the machine has been made the subject of a separate application.

Referring to Fig. 1, the mode of use of the.

presentvalve finishing tool is substantially the same as that described in my prior application, Serial No. 340,770, valve seat reconstruction tools, filed February. 18, 1929, and the present reamer is preferably employed with a pilot stem 45 of the type shown in my prior application, Serial No. 310,600, valve seat reconstruction'tools, filed October 5, 1928.

A pilot stem of this type is provided with a frusto-conical surface 46 adapted to engage the edges of a valve stem guide 47 in an engineblock 48, and the pilot stem is also provided with a tri-partite split end 49 adapted to be expanded by an expansion rod 50 which cams the parts of the split end 49 into engagement with the lower end of the guide 47. The pilot stem 45 is thus axially aligned in the valve stem guide 47 and adapted to support the tool holder 13 slidab-ly and rotatably by the pilot stem in such manner that the reamer 10 may be fed downward as necessary, and rotated upon the true axis of the valve stem.

The present method of valve seat finishing differs from the prior art in the elimination of the step of lapping or grinding the Valve and the use of a plurality of cutting edges disposed at different angles enables the production of a perfectly finished valve seat by a one-step method. Manufacturers of motor cars who have always found it necessary in the prior art to grind in their valves are now enabled to produce a perfect finish upon the valve seats, merely by the use of a reamer,

thereby greatly decreasing the amount of labor involved and the cost of finishing the valve seats.

It will thus be observed that I have invent ed an improved method of manufacture of valve rcamers or similar tools, which results in a superior product having improved operatlng characteristics, and I have al o invented an improved one-step method of finishing. valve seats, which eliminates much of the.

labor and expense incident to the finishing of valve seats by the methods of the prior art.

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 claims.

Having thus described my invention, what at each step, changing the position of said body with respect to the cutter between cuts to change the depth of cut and spacing of edges, supporting said body on its true axis, rotatingsaid body and grinding the cutting edges while so supported.

4:. The method of making a valve seat reamer which comprises forming a blank, rotating the blank upon an eccentric axis a nd making cuts therein at spaced intervals, said cuts being at an angle to the eccentric axis,

changing the position of the blank and the cutter with respect to each other between each cut to change the characteristics of the cut, rotating the blank on its true axis and grinding the cutting edges.

5. The method otmaking a valve seat reamer which comprises forming a blank with a substantially frusto-conical surface, rotating the blank upon an eccentric axis and my name this 26 day of August, 1930.

FRANS O. ALBERTSON.

I claim is new and desire to secure by Letters Patent of the United States, is:

1. The method of constructing cutting tools, comprising, forming a blank body, rotating said body upon an eccentric axis, mak-' ing cuts in said body to form cutting edges, rotating said body .upon its true axis and grinding said edges.

2. The method of making valve reamers, comprising supporting a reamer body on an eccentric axis, rotating said body on said axis step by step, and making cuts in said body at each step, and changing the positior. of said body with respect to the cutter between cuts to form cutting edges of varying spacing and angularity.

The method of making valve reamers,

comprising supporting a reamer body on an eccentric axis, rotating said body on said axis step by step, and making cuts in said body

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