US2055341A - Method of making tappets - Google Patents

Description

H. l. DYER lMETHOD oF MAKING TAPPETS FiledJuly 5, 1934 Sept. 22, 1936.

A TTORNEY.

Patented Sept. 22, 1936 ME'JHOD4 GF MAKING TAPPETS i Harold `Dyer, 'Sattl'el Creek,-Mich., assignorto Wilcox-Rich Corporation, a "corporation of lvlichisan V l. .ApplicationJuly 1934, Serial No. 733,821

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My invention relates to the construction of steel valve tappets for `internal combustion engines. These devicesV are used to transmit the thrust of the cam to valve stem. They require a hard wear resisting face for contact with the `camy and also a face which is not brittle or easily fractured.`

Heretofore it has been customary toi construct tappets with a steel ,body member and a cast iron heador wearing face for contactwith the cam. Hard cast iron provides asgoodfa wearing surface as is known, but ithas'the disadvantage of being more fragileand brittle than steel. Increased engine speeds and valveloads have made it necessary andzdesirable to provide a tappet construction in lwhich the head member has practically .comparable wearing qualities to cast iron, but is stronger .and less subject to fracture by impact. w l

Variouswsteel constructions have heretofore been proposed, among them the constructions wherein a piece of relatively hard Wear-resisting steel is attached to a rod or body of softer steel ofathe same size and the combined-article is then forged to shape and join the head andbody members as desired. This requires 'a considerable amountof .forgingand'a deformation and re'- workingof thehardsteelfacing materialand the body member. Steel, suitable for the facing memb er is not easily` machined, orvvorked'byf forging, and it is consequently desirableto provide a con@ struction in which the forging and machining of the face member may be substantially eliminated. One object of my invention is to provide 5a tappet construction wherein a hard steel facing member may be .attached to aLfsofter steel body and secured` thereto without the necessity of reworking the hard steel-head or facing member to anysubstantial degree.,V

. AnotherV object is to` provide a tappet construction wherein the forging operation isV performed only upon the soft steel body portionof the tappet and whereinthe amount of forging necessary to form the tappet is substantially diminished.Y

With these andother objects-in view, my invention consists fin the combination, arrangement and Aconstruction of the-various parts of my `improved structure described and claimed inthe accompanying specification, andshown in the drawing,` in which: l l 'Figure 1 is Va longitudinal cross-sectional view of a blank foria tappetbody'constructed according to my invention. v Fig. 2 isa longitudinal'cross-sectional view of a tappet body-f'after' being formed by fforging,and

of a steel head or face member which is to be attached thereto.v lFig. 3 is afview in elevation and partly in section of the body and head*v member joined together, showing one form of the ultimate construction. i v Y u `Figl 'is' a longitudinal cross-sectional view showing a modified form of tappet` embodying my invention. l

` Fig'. 5`is a third'modication of tappet embodying my vinvention shown in longitudinal crosssection.

Fig; 6 is-a fourth modification of tappet construction embodying my invention and shown in longitudinal cross-section.

In Fig. 1 I have shown a preformed tappet body or stem I made of a machinable steel which isv capable of suitable hardening by heat treat-` ine'nt. Thismay be fashioned as a screw machine product, or by any other suitable means, to provide a hollow tubularbody portion with a relatively large bore 2 through the major part thereof to provide relatively thin Walls and eliminate as muchweight as possible, and with a reduced bore `3 and consequently thicker walls which may be internally threaded to receive the'threaded shank of the conventional adjusting screw, not shown, which is. customarily inserted in the ends of these tappets to adjust the clearance between the end ofthe 'valve stem and the tappet, asis well understood by those familiar with the art. The end opposite to the reduced bore is formed with thickened walls 4, as shown, which is later fashioned, as hereinafter explained, to provide a support for the head or wearing face of the tappet;

V11n Fig. 2 I have shown the body I after a forging operation in which the thickened end 4 has been forged to form an outwardly extending annular vand lateralange 5. The portion of the thickened part of the wail 4 which is not contained in the lateral flange 5 has been forced inwardly, as shown, and forms vathickened wall portion at the flange end of the tappet body which-restricts the enlarged bore therein and which provides a reinforced neck portion for thetappet Vimmediately beneath the flange 5 to which the head or camf contacting face o f the tappet is tobe secured. `The cam, contacting face orfhead of the tappet is composed of an"a',nn1`1la"` disc 6 of a hardenable impact and wear-resisting metal or alloy which may be punched from sheet stockor `cast to substantially the desired ultimate size. The metal is preferably o'f somewhat different character than that of the tubular body of the tappet. Steels suitable for this. purpose, such as those comparable to the standard S. A. E. steel specification 52-100,

' are not easily or readily machinable and forgegreatest wear naturally comes upon'the face or head of the tappet which is in contact with the cam, the wear on the body occurring only inlits contact with the sleeve guide,- andthe Ysurfaces of the tappet body and the guide are not subjected tothe impact or pressure orfriction which.` the cam contacting face must bear, andtherefore do not require as great hardnessA or wearresisting quality as the face member. Y

After the body has been flanged and formed, asshown in Fig. 2, the head member 6 is superposed over the flange and iswelded to the flange by seam vveldingat I between the outer edge of the flange and the overhanging edge of the head member 6. This adequately secures the head member to the body and. provides aA construction in which substantially all of the machining and forging is accomplished upon the material of the body which is more readily subject to these operations, and the head need only be ground4 slightly to bring it to final dimensions and finish,V as it has been cast, or punched from the stock sheet, to substantially the ultimately desired size. Y

A modified form shown in Fig. 4 is constructedin the same manner as the form shown in Figs.l 1, A 2 and 3, previously described. the` only difference being in the formation of the anged end of the body by the forging operation which is slightly` different from the formation shown ink Fig. l2, 'and provides a tapering flange 5 to which the head member 64 is attached by seam welding as described in connection withl Fig. 3.

In the modification shown in Fig. 5 the flanged end of the body member I is not provided as shown with the thickened wall portion beneath the flange,V although this may be incorporated in this form if desired. In this modification the yflange 5 is tapered and provided with a chamfered outer edge I0. The head member 6 is also provided with a chamfered inner edge Il and the head member 6 is then superposed upon the Aflange 5 as shown with the inner edges of the cham/fer on each part contiguous and providing a notch or a groove I2 around the edge of the joined parts. The parts are then secured together by puddle welding which consists in puddling a4 welding material in this groove I2 to form an integral bondbetween the members.

In the modification shown in Fig.`6 the anged end vof the body is formed in much the same manner as that shown-in Fig. 5 except that the flange5is not tapered to the extent shown in Fig. 5 but is somewhat thicker and is terminated short Qf the outer edge of the Yhead member 6. In this form, asin Fig.5, the Walls of the body member beneath the flange may be thickened if desiredl as shown in Figs. 3 and 4. In this form the head member Gis formed to a cup-shape as shown with an upturned ange around the edge ofthe member which vilts over the outer edge ofgtheannular flange 5.- The head member is then joined to the body member I by means of ily-A permitting these operations. t memberrwhich must be of a material having high a seam weldalong the joint line of the contiguous parts as at I3.V

'I'he construction described enables the tappet to be formed of steel materials having different characteristics, each suitable to the functions to be performed and each also suitable and adapted to the various machining and forging operations which must be performed upon it. The body member which must be of a material that may be readily machined and forged is formed of a metal or alloy having characteristics read- The head wearing qualities. not easily machined or forged, may be provided and secured to the body member'with a minimum of machining or forging operations. "This 'construction and method pro- 'videsa soundand strong tappet of different Ymaterials particularly adapted to the service required Aof them, and it also provides a cheap,

and efcentmethod iof making.4 such a tappet.

Formal;,changes may be made in the specific embodiment of .the invention described without departingV from the Aspirit and substance of the broad invention, the scope of which is commensurate Withthe -appended claims.

I claim: l. The method of making a tappet comprising: providing, a tubular body of machinable and forgeable-steel rwith a relatively small bore in one end thereof and a relatively large bore in the other end thereof; forming an annular lateral flange on said relatively large bore end; and then securing a preformed disc of wear resisting, but relatively non-machinable and nonforgeable steel upontheange of said steel body by seam welding the edges of said ange to the underside of said disc.

2. VThe method of, making a tappet comprising: providing a tubular body of machinable and forgeable steel with arelatively small bore in one end thereof. and a. relatively large bore in the other end thereof; upsetting the relatively large bore end to'thicken the` walls thereof. and to form an annular lateral outwardly extending flangey thereon; and then securing a preformed discof ywear resisting, but relatively non-machinable and non-forgeable steel to said ange on said steel body by seam welding the edges of said flange to the underside of said disc.

. 3. The method of making a tappet comprising: providing a tubular body of machinable and forgeable steel `With'a relatively small bore in one Vend thereof anda relatively large bore in the other endwthereof; Vforming an annular outwardly extending lateral ange on the large bore .end of said body andchamfering the outer edges of said flange; superposing a preformed disc of wear resisting, but relatively non-machinable and .non-forgeable steel and having a chamfered inner edge upon said annular flange; and then securing said discto said. flange by welding in the groove formed by thechamfered edges of said disc andange.

4. Themethod of making a tappet comprising: providing a tubular body of machinable andfo-rgeable steel with a relatively small bore in one endjthereof and a relatively large bore in the other end thereof; forming an annular outwardly extendingl flange on the relatively large bore end of said body; superposing a preformed disc of wear resisting, but relatively nonmachinable. andnon-forgeable steel and having an upturned flange around itsedge. upon the annular flange of said steel body with the ange of said disc embracing the edge of the annular ange on said body; and then Welding said parts together at the underside of the disc along the line of contiguity of said respective flanges on said body and disc.

5. The method of making a tappet comprising: providing a tubular body of machinable and forgeable steel with a relatively small bore 10 in the one end thereof and a relatively large bore in the other end thereof; forming an annular outwardly extending lateral ange on the large bore end of said body; superposing a preformed disc of Wear resisting, but relatively nonmachinable and non-fo-rgeable steel upon Said annular ange of said steel body; and then securing said disc to said flange by welding the same thereto without upsetting or deforming either said flange or disc.

HAROLD I. DYER.

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