US1882690A - Valve seat reamer - Google Patents

Description

3 Sheets-Sheet l Oct. 18, 1932. F. o. ALBERTSON VALVE SEAT REAMER Filed Nov. 18, 1929 Em OJ Oct. 18,1932. Q ALBERTSQN 1,882,690

VALVE SEAT REAMER Filed Nov. 18. 1929 3 Sheets-Sheet 2 13 123 @fi 5421 6 0 1/ rnW- I Ililllll 1m 1111 7 26' wflwiw. may.

Oct. 18, 1932. F. o. ALBERTSON 1,832,690

VALVE SEAT REAMER Filed Nov. 18, 1929 3 Sheets-Sheet :5

amt/Arm Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE FBANS O. ALBEB'ISON, OF SIOUX. CITY, IOWA, ASSIGNOR '10 ALBEBTSOK Q; comm, INC, OF SIOUX CITY, IOWA, A CORPORATION OF IOWA.

VALVE SEAT REAHEB Application filed laovember 1a, 1929. Serial 10.407377.

The presentinvention relates to valve seat finishing tools, and is particularly applicable to 'tools of the type known as valve reamers. The present application relates particularly 3 to the valve seat reamer, while the method of making the valve seat finishing tools has been made the subject of a divisional application, Serial No. 47 9,590, filed September 4, 1930. While the present tools are peculiarly 41 adapted to efiect finishing of the valve seat in a manner not capable of accomplishment with the tools of the prior art, it should be understood that the present tools may be used for all kinds of cutting or reconstruction operations on valve seats or similar work.

In the finishingor reseating of the valves of internal combustion engines, the reamers or'other tools of the prior art have not been capable of forming a perfectly finished valve seat, and it has always been necessary to use a lapping or grinding operation in order to attaln the degree of perfection which is desirable for modern internal combustion en- :3 gines. This grinding orlappingfoperation is usually performed witlithe valvejn place, by putting a small amountofgr-inding compound on the seat or valve and by oscillating the valve upon its axis with the valve enugaging the seat, and the. grinding of the valve on the seat is relied upon. to secure a perfect fit between the valve and the seat in the devices of the prior art.

The reason for'such lapping or grinding :15 operation was that it was practically impossible for the prior .reamers to finish a valve seat with a uniformly perfect'seating surface and aclose examination and test of the valve seatsmade by the tools of the prior art shows 4 that there are numerous waves in the surface of the valve seat, consisting of minute hills and valleys, generally extending radially with respect to the axis of the valve and seat.

45 One of the most important factors con- -been able entirely to eliminate the chattering struction tool which is capable of producing tributing to 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 avoid the chattering of the reamer, generally by varying the number of teeth used and by using an odd number of teeth.

None of the devices of the prior art have and resultant high and low spotsproduced in the valve seat, and consequently the finishing of valves with the tools of the prior art always consisted of at least a two-ste method, the last step being the lapping in o the valve with the valve grinding compound and a machine for oscillating the valve.

One of the objects of the present invention is the provision of an improved valve seat reamer, by means of which the customary grinding or lapping operation may be eliminated.

Another object is the provision of an improved valve seat reamer or valve recon- 70 a substantially perfect valve seat surface.

Anotherobject is the provision of an improved valve seat. reamer or the like, having novel and advantageous operating characteristics, and which is adapted to e produced in quantity at a very low cost, thereby placing the reamer within the reach of a vast number of purchasers.

, Another object is the elimination of the undesirable factors of chattering or uneven cutting whichwere present in the reamers of the prior art, -andthe provision of an improved reamer capable of producing a more perfect finish upon a valve seat Other objects and advantages of the invention will be apparent from the following description and from the accompanyin drawings. in which similar characters of re erence indicate similar parts throughout the several views.

- stantially along the Referring to the drawings, of which there are three sheets;

Fig. 1 is an elevational view in partial section, illustrating the mode of use of the 5 reamer and the one-step method of finishing valve seats, the reamer illustrated being a reamer;

F i 2 is an elevational view of a 30 reamer of the type shown in Fig. 1;

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

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

Fig. 5 is an enlarged bottom plan view of the same reamer;

Fig. 6 is an enlar ed sectional view taken on the plane of the line 66 of Fig. 5;

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

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

Fig. 9 is a diagrammatic view of the appa- IEtILS used in the sharpening of the reamer teet 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 eatures and characteristics of the teeth are difficult to distinguish with the naked eye, the views of Figs. 4, 5 and 6 have been drawn on a scale three times the size of the reamer.

The reamers are preferably constructed of substantially cylindrical bodies 10 of the best tool steel and rovided with a substantiall fiat upper sur ace ,11 for en a 'ement with feeding devices and with a s ig htly tapered bore 12 having its largest endlocated at the top 11 of the reamer, so that the reamer 10 may be secured upon a tool holder 13 by the frictional fit of a complementary tapered portion 14 in the tapered bore 12.

The body 10 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 s1 e 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 subangle of the reamer desired. v

Thus, for a 45 reamer, the general direct1on of the feed against the cutting tool would be at 45 to the axis of rotation of the reamer blank which 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-conical surface of the blank having a larger diameter at the top, it is desirable that the pitch of the tooth be increased to correspond with the larger diameter.

In making reamers of the type illustrated,

- which would be the case it will be observed that the flat or slightly concave surface 37 formed by the sharpening operation, is of substantially the same widt across the tooth, thereby decreasing the amount f material which must be ground away in t e sharpening operation, below that 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 flllSlJO-COIllCfil surface of the reamer blank has a greater diameter, the teeth 17 would be very wide adjacent the outer ed 0 of the reamer.

he exact angle at which the dividing head should be set, and consequently the angle of feed for any milling cutter, any given number of teeth and any degree of reamer, may be ascertained 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 25", and the axis of rotation of the increasingepitch on reamers of any angularity, may determined from standard tables. The ordinary commercial sizes of reamers are 15, 30, 45, and 75,"but it.

will be understood that an of reamer ma be constructe It should al so be understood that the exact shape of the cuts produced by the cuttin tool depend upon the ty e of tool employe and the provision of su stantially flat sides on the teeth 17 is incidental to the cutting of reamers with milling tools.

One of the most important features of the present invention is the exact direction in which cutting 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 u on the horizontal base line 20 is indicated y the numeral 21.

desirable size It has already been pointed out that the 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 the axis of the reamer.

The effect of this change in the direction of the cutting edges canbest be understood by comparing the action of two radial cutting edges such as are provided in the prior reamers, with two of the cutting edges of the present tools.

Assuming that one of the prior reamers had radial teeth and the first tooth chattered slightly and produced some radially extending valleys and hills on the seat, the next radial tooth would be exactly in line with the direction of these valleys and the undesirable chattering effect would be accentuated with further undesirable results. Assuming that the present valve tool wasemployed 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 different angle, so that it would straddle the valley and also produce some shearing cfi'ect on the seat during the cutting operatlon. Thus, each of the cutting edges of the present reamer is preferablydisposed at a slightly different angle, but the amount of dlvergence between a radial line and the cutting edges issominute that it-cannot be distinguished by thenaked eye alone.

In the present embodiment of the invention, which represents a form most conveniently and economically n aufactured, 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. 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 36, inclusive, extend along lines drawn to the point 21 which is spaced slightly from the true center 19.

It will thus'be observed that all ofthe 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"radia'l 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 the radial line being theoretically equal to zero.

Each of the teeth 17 is provided with a slightly flat or concavely curved surface 37, which is formed by the sharpening operation at the juncture of the surfaces 27 and 16 on the various teeth, and which forms the cutting edges 22 to 36, inclusive. The particular form ing to the method described hereinafter have cutting edges of varying angularity best illustrated in Fig. 7 which is a development of the periphery of the reamer. The angularity of the teeth varies, not only with respect to radial lines drawn from the axis of the reamer, but certain of the teeth vary by a veryslight degree from the 45% angle desired on the valve seat, as, for instance, in Fig. 6 the tooth 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.

This result is thought to be due to the clearance which is provided for the cutting 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 the 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 knojvnto be a practically perfect 45 valve r seat.

The method of manufacture of the present reamers 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 37 the reamer cutting machine.

The reamer cutting machine is illustrated in detail in my co-pending application, Serial No. 414,392, filed Dec. 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 eccentrlc 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 5 indie 38 is adapted to support the blank uring the cutting operation and provide means for rotating the blank upon an eccentric axis into the successive positions for the formation of the, respective teeth. The spindle 38 is preferably supported upon a fssf dividin head, m

ted to rotate the spindle and the reamer w ch it supports through equal an ar increments, but the variations in elevation of the dividing head and the eccentricity of the spindlevary the spacing, depth, and angularity of the teeth formed, as

described hereinafter.

The reamer cutting, machine is rovided with some means for raising and owering the spindle 38 to regulate the depth of cut of a milling cutter and with means for securing the blank in any of the respective positions to which it may be moved step by step. The cutting machine is also providedv with the milling cutter 40 supported upon a 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 or makin a 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 10 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 roduce a cut having the walls 15 and 16 of Fi 5. The milling cutter is then withdrawn, t e reamer body rotated on its eccentric axis one step to the position for the making of the next cut,

and at the same time the elevation of the spindle 38 with respect to the milling cutter 40 ma be adjusted to any desired amount.

In t e reamer' cutting machine of the above mentioned application, automatic means is rovided forraising and lowering-the reamer etween the cutting operations, so that the respective cuts may be made to give cutting edges of substantially the same length in the finished reamer. It should be observed that inFig. 5, the cuts made at the left-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 sameelevation of the reamer were employed to make cuts at both of the sides of the reamer, the cuts made adjacent the edge 22 would be much deeper than the cuts made adjacent the edges 29 and 30, because the eccentricity of 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 slnce 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 ofthe teeth ma be made, and the spacing il.ustrated in ig. v6

- neaaeed is to be regarded as exem lary of but one form of the invention. e result of this cutting operation is a reamer which. has teeth 17 with edges extending along lines conver 'ng .in the eccentric axis 21, so that all of fiie edges on the teeth are tially difierent angularity.

he reamer is then supported upon an ordinary tapered s indle 42 and each of the teeth 17 is groun with a grinding wheel 43 which is disposed upon a shaft 44 to grind the outer flat surfaces 37 of the teeth 17 to substantially conical form, that is, the shafts '42 and 44 would be disposed with their axes within substantially the same plane were it not for the fact that it is necessary to provide the teeth 17 of the reamer with some slight clearance by the removal of some of the material behind the cutting edges 22-36. For this purpose, the shafts 44 and 42 have their axes disposed in parallel planes, but the grinding wheel axis 44 is slightly below the plane ofthe shaft 42.

The reamer grinding machine may be of the usual form device for holding the reamer sition 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 ed e of the tooth, as shown in Fi 9.

ince the reamers are (ground with a grinding device which woul ordinarily produce a frusto-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 b a cutthrough a frusto-conical surface so t at the cutting edges of the teeth approximate lines geometrically known as conic sections. Such lines are slightly curved, the curvature depending upon the lane through which the conic section is ma e, 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 ma be made for a more complete'understand ing 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 present valve 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,

in proper poof substanprovided with a stop or other and the present reamer is preferably employed with a pilot stem 45 of the t pe shown in my prior application, Serial 0. 310,600, valve seat reconstruction tools, filed October 5, 1928. e

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 engine block 48, and the ilot stem is also provided with a tri-partlte split end 49 adapted to be expanded by an expansion rod 50 which cams t e parts ofthe 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 slidably and rotatably by the pilot stem in such manner that the reamer 10 ma necessary, and rotate of the valve stem. 1

The present method of valve seat finishing differs from the rior art in the elimination of the step 0 lapping or grinding the valve andthe 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 alwa s found it-necessary in the p)rior art to rin in their valves are now ena led to pro uce a erfect 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 invented an improved method of manufacture of valve reamers or similartools, which results in a superior product havin improved operating 0 aracteristics, and have also invented an improved one-step method of finishing valve seats, which eliminates much of the labor and expense incident to the fin-y ishing of valve seats by the methods of the prior art.

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

1. A reamer of predetermined degree of.

angularity, having a multiplicity of teeth lying substantially in a conical surface of said degree, one of said teeth having a primary cutting edge and the other of said teeth having cutting edges increasing by increments in divergence of angularity from said primary cutting edge.

2. A reamer of predetermined degree of angularity, having a multiplicity of teeth lybe fed downward as upon the true axis 3 vergence of angularity from said primary cutting edge.

3. A valve seat reamer, having a multiplicity of teeth with cutting edges including a primary cutting edge located substantially in a frusto;conical surface, said reamer being arranged with a series of cutting edges of increasing divergence of angularity from the primary cutting edge in said surface, but diverging slightly in angularity from said frusto-conical surface.

4. A valve seat reamer, comprising a metal body formed with a plurality of grooves extending substantially in the direction of the. angularity of the valve seat with respect to.

the axis of the valve, the walls of said grooves forming teeth, all of which have cutting edges which are all located along lines drawn, to a single point which is eccentric with respect to the axis of said-reamer.

5. A valve seat reamer, comprising a metal body formed with a plurality of grooves extending substantially in the direction of the angularity of the valve seat with respect to the axis of the valve, the walls of said grooves v forming teeth, all of which have cutting edges which are all located along lines drawn to a single point which is eccentric with respect to the axis of said reamer, said grooves each being formed with a pair of diverging plane surfaces and the depth of said grooves increasing from the side of the reamer adj acent said eccentric point in both directions toward the side of the reamer opposite from said eccentric point.

6. A valve seat reamer comprising a body having a. plurality of cutting edges, allof which are located on lines converging toward a single point eccentric with respect to the axis of said body, said edges lying substantially in a frusto-conical surface and said cutting edges being unequally spaced from adj acent cutting edges.

A valve seat reamer, comprising a body ha ing a multiplicity of cutting edges including a primar cutting edge located at a predetermined va ve seat angle and said primary cutting edge being located on a line passing through the axis of said reamer, the others of said multiplicity of cutting edges diverging in both directions from the predetermined reamer angle and being located on lines passing through a single point eccentric with respect to the axis of said reamer.

8. A valve seat reamer, comprisin a body having a multiplicity of cutting e ges, including a primary cutting edge located at a predetermined valve seat angle, and located on a line passing through the axis of said reamer, and a multiplicity of other cutting edges diverging in both directions from the predetermined reamer angle, all of said other edges being cutting edges converging at a point located outside the reamer axis and said other cutting unequally spaced with respect to ad acent cutting edges.

In witness whereof, I hereunto subscribe my name this 14th day of November, 1929.

FRANS O. ALBERTSON.

Images