US1650644A

US1650644A - Valve tappet and method of forming the same

Info

Publication number: US1650644A
Application number: US708048A
Authority: US
Inventors: William C Osterholm
Original assignee: WILCOX PRODUCTS CORP
Current assignee: WILCOX PRODUCTS Corp
Priority date: 1924-04-21
Filing date: 1924-04-21
Publication date: 1927-11-29
Anticipated expiration: 1944-11-29

Description

W. C. OSTERHOLM VALVE TAPPET AND METHOD 0F FORMING THE SAME Nv.- 29, 1927..l

Filed April 2l. 1924 lil WILLIAM C. OSTERHOLIVI, 0F OAK SPARK, LLIOIS, ASSIGNOR TO WILCOX PRODUCTS CORPORATION, 0F SAGINAW, MICHIGAN, A CORPORATION 0F MICHIGAN".

. L VALVE TAPPETI AND METHD @E FURIVHNG; THE SAME.

Application led April 21, 192e.: Serial No. 708,04l.

The invention relates tu valve lifters'or tappets and has tor its objects; rst, reduc tion in the costv of manufacture; second, the obtaining of a light durable structure; third, various other advantages as hereinafter set forthi ln t-he drawings:

Figure l illustrates the blank from which the tappet head is formed;

Figures 2 and 3 are cross sections showing successive steps in the forming of the head; l

Figure d is an elevation of the blank from which the stein is formed;

Figure 5 is a stem formed from the blank;

litigare t is an enlarged section illustrating the manner of securing the stem to the head;

Figures 7 and 8 are sectionsshowing moditied constructions ot stem; I

Figure 9 is a section through the stem and head showing another modification; A

Illigures l0 and ll are sections showing successive steps inthe manufacture ot the Vennstrnction of Figure 9.

lt is the primary object oi the invention to separately torni the head and stem ot the tappet, this permitting both of economy in the use oli material andthe selectionL oi" qualities best suited for the respective' parts. the manufacture et tappets it is usual to form the same ot single blanksy which may he either forged, cast or formed in various Ways. IThe various operations -re quired in the nishing of these lblanks are such as to involve a considerable cost in manufacture, and the fact that the structure is all el one material precludes theselection et special qualities tor diderent portions thereof. For instance, the head, which is subjected to the Wear ofthe cam, needs a hardenc-id bearing surface, While the stem is stronger and'better it left comparatively soft.. rlhe diilerence in hardness may be se-d cured by suitably controlled heat treatment, but this adds to the complexity and cost of manufacture.

lrlleretotore certain constructions ol tap pets have been made from separate blanks, but such structures tor various reasons have not proven altogether satisfactory and diiiiculty is experienced in securely uniting the head ot the stem. With my improved structure this diculty is entirely eliminated and the resulting structure is superior to those formed from the single blank.

As shown in Figures l to 6, the method of manufacturing my improved tappet is as follows: A round disk blank of sheet metal A is fashioned, preferably by a coining press, to form a recess B, as shown in ligure Q. The annular Walls ot this recess are undercut, as shown in Figure 3, and the tace of the recess is preferably curved, as shown, :tor the purpose hereinafter described. The blankniay be formed of selected material and after iashioning may be given suitable heat treatment to secure the proper degree ot hardness.

The stem may be formed in various Ways, but as shown in Figure d the blank D isa suitable length or round bar metal.. yl"his blank is then bored to form apertures ot diderent diameters at the opposite ends, the smaller aperture lll being threaded to receive the usual adjustment screw. This end of the blank may also lbe pressed or other- Wise fashioned into a polygonal tmorm to produce a Wrench hold. 'The larger bore l? is ot such adiameter as to reduce the Walls to the required thickness. The end of the tube is then tlared, as shown at G, by pressing in suitable dies, or by other means, so as to torni an oblique Harige ot a diameter slightly less "than the diameter ol 4the recess ld.

"lhe head and stein are united by endrrise pressure, Whichresults in turning the oblique dange Gr into a plane substantially perpendicular to the axis of the stem and thereby expanding the diameter so as to force the outer edge against the undercut annular Wall into interlocking engagement therewith. rlhis interlocking is facilitated by the anguiar movement of the flange G which expands the lower portion thereof to a greater diameter than the upper portioncontorming to the shape of the Wall. Also, by curving the bottom of the recess as shown atl-l, the dange oii the stem will ,be conformed thereto Without forming a sharp bend. Still another advantageous edect is that the inward pressure ot the annular Wall C, which resists the expansion oil the Harige G, Will torce the adjacent portieri ofthe tube slightly inward, resulting in a clearance groove lt. 'lhus when soV ' during the pressing operation..

I conical face P to produce the the stem is subsequently groundor machined for engagement with the guide bearing, this clearance groove will avoid necessity of grinding or machining immediately adjacent the head.

The structure formed as just described is one where there will be no tendency for.the head to separate from the stem as these parts are rmly interlocked. Furthermore, there is a constant outwardtension on the iange G, due to the resiliency of-the metaland the fact that the adjacent portion of the tube has been slightly contracted in diameter The chamber within the stem may be used asa lubricant container and I have therefore Afashioned the central portion of the recess of cup form, as shown at J, with a central aperture. K for feeding the lubricant directly onto the cam.

As has been stated, the stem may be ormed'in lvarious ways, such for instance as by any of the usual methods of drawing a tube from a sheet metal blank. During this drawing operation the flared ange at the end of the blank is easily formed so as to be ready for engagement witha head in the manner previously described. Where, however, the blank is made from sheet metal, the walls are of substantially uniform thickness and it may be necessary to provide a bushing for the threaded end. This bushing Lmay be formed as shown in Figure T with a peripheral groove M into which the tube is pressed by rolling or other suitable means, effecting the interlocking engagement. Figure 8 ,shows a cupped bushing L for receiving t valves, said bushing being similarly locked to the stem.

' In Figures 9, l10 and 11 a furtherl modification is shown wherein a tube of uni' form diameter is expanded by endwise pressure to engage and interlock with an oblique annularslot N in the head. With-this construction the head O may first be formed as shown in Figure P surrounded by a an e Q, parallel to the axis. v The ange Q, is t en compressed and forced inward into parallelism with the oblique slot N.

With all of thevarlous modifications the stem is interlocked with the head by the expansion thereof due to endwise pressure. Also this operation is performed after the completion, including the heat treatment, of the head so that there is no necessity of any further lheat treatment 4or any operation which might tend to loosenthe joint.

When the is pressed intol a plane perpendicular" to the axis, there is some danger of concentrating the stresses at the bend and overstraining the metal. Such an effect I have avoided by first forming the flaring portion,`- as Y' portion and a heppush rod of overhead' 10 with a conical face flaring end portion of the stem said stem member with an outwardly Haring shown specifically in Figure 5. It will be noted that as thus formed the portion irnmediately adjacent to the cylindrical portion of the stem is initially bent to approximately the plane perpendicular to the axis, while the outer portion is oblique to the axis. With such a form the pressure applied to expand the stem into the head will only react on the flaring outer portion thereof and will not concentrate any bendin stress at the angle between the cylindrical part and the fiange; also, as the metal is chiefly in tension, it will be drawn wit-hout fracture. Still further, the portion adjacent to the lower surface of the flange will be expanded to a greater extent than the upper surface thereof so as to fill the undercut portion of the recess in the head.

What I claim as my invention is: 1'. The method of manufacturing tappets comprising the separate forming of a head member and a tubular stem member, said stem member having an annular end portion which is relatively oblique to asurface on said head member and said head member being undercut adjacent to said surface, and applying endwise pressure to said members to turn the end portion of said stem member and to force the same into interlocking engagement with the undercut portion of said head member.

2. The method of manufacturing tappets comprising the separate formingrof a head member and a tubular stem member, said head member being provided with an undercut surface adjacent thereto which is relatively oblique to an annular end portion of said stem' member, and applying endwise pressure to said members to turn the end of said stem member by the relatively oblique portion of said head member and into interlocking engagement with the undercut `portion thereof.

to said members'to outwardly bend the end portion of said stem member and to force the same intointerlocking engagement with said annular undercut portion,

' 4. The method of manufacturing tappets comprising the separate forming of a head member and a tubular'stem member, said head' member being provided with an annular radially outwardly undercut portion and said flaring portion into'parall'elism with the lll) Leeoae adjacent surface of said head and to thereby expand the same into interlocking engagement with said undercut portion.

5. rlhe method of manufacturing tappets comprising the separate forming of a disk head and a tubular stein, said head being provided with an annular radially outwardly undercut portion and said stein with an outwardly-lared annular end portion non-parallel to thel adjacent surface of said head,

and applying endwisepressure to said members to bend the end portion of said stem.k

into parallelism with said head and thereby to peripherally interlock undercut portion.

6. The method of manufacturing tappets' the same with lsaid comprising the separate fashioning of a diskf h'ead member and a tubular stem member, said head member being provided with an annular radially outwardly undercut shoulder and a curved surface adjacent thereto, said stem being provided with a flaring annui lar end portion non-parallel to said curved portion on saidhead, and applying end- Wise pressure to said members tobend the flaring portion of said stem into parallelism with the curved portion of said head and to thereby peripherally expand the stem into interlocking engagementwith said undercut shoulder.

7. The method of manufacturing tappets comprising the se arate forming of ahead Amember and a tu ular .stem member, said stem member being fashioned with a flaring annular end portion which in its outer part is more oblique to the axis of the stem than in the part immediately adjacent to the stem,

' said head being provided with an annular undercut portion, andapplying end pressure to said members to bend the oblique portion of said stem and to peripherally-expand the same into interlocking engagement with the undercut portion of said head.

8. The method of manufacturing tappets comprising the separate forming of a head memberand a tubular stem member, said stem member being fashioned with a Haring annular end portion which adjacent .to the body portion thereof is substantially in a plane perpendicular to the axis and is more obliqueto the axis in its outer portion, said" head being provided `with an annular undercut shoulder of sulicient minimum diameter to receive the Haring portion of said stein and in applying endwise lpressure to said membersto bend the oblique portion of said stemsubstantially into a plane perpendicular to the axis and thereby. force the same into interlocking engagement with said annular undercut shoulder.

9. The method of manufacturing tappets comprising the separate forming of a headl member` and a tubular stein member, said stem member being bfashioned with walls of greater thickness at one end thereof and with a flaring annular portion at the oppositeend thereof and said head being provided with 'an undercut annular shoulder of a minimum diameter` sufficient to receive said flaring portion, and in applying end pressure to said members to peripherally expand said flaring portion of the stem and to force the same into interlocking engagement with said annular undercut portion of the head.

l0. A tappet comprising a one piece head member recessed to form a bottom surface and an annular undercut shoulder, and a tubular .stem member lprovided with a ilarling end portion engaging said recess and interlocked with said undercut shoulder, said flaring end:I portionalso having its .lower surface contacting for its entire length with the bottom surface of said recess. n

11A tappet comprising a head member recessed to form an annular shoulder, and `a tubular stein member provided with an annular flange at one end thereof extending substantially in a plane perpendicular to the axis and interlocked with said annular shoulder.

' 12. A tappet comprising a' head recessed to form an annular shoulder and With a curved surface tangent to the bottom of said recess and a tubular stem having an annular flange at one end thereof rounded to lie against said curyed surface of the head and with an outer portion substantially in a plane perpendicular to the axis of the stem and Vinterlocked with said shoulder. .Y 13. A tappet comprisingl a head recessed to form a bottom surface and an annular -undercut shoulder, and a tubular stem-having an annular flange extending substantially in a plane perpendicular to the axis of the stem, said flange having its lower surface engaging the bottom surface of said recess and having its outer annular edge interlocked with said undercut shoulder.l

to said Harige being of slightly less radiusl than the tubular portion.

15. A tappet comprising a head recessed to form an annular radially undercut shoulder with an inwardly extending curved surface tangent to the bottom of the recess and a tubular stem provided with an annular Han e extending substantially in a plane perpen icular to the axiswith its periphery interlocked-with said undercut shoulder and the portion intermediate said peripheral Y portipn andthe body portion curved to fit lthe, curve of `said 4head 'and reinforced thereby.

P 16. A tappet comprising a disk head reisc cessed to form an annular undercut shoulder with an inwardly extendingcurved surface of sald head and the central recess drainling the lubricant within the stem towards said central aperture. Y Y

17. A tappet comprising a disk head recessed to form an annular shoulder and a tubular stem having thickened walls at one end thereof and a polygonal exterior, the opposite end of said stem being provided with anannular fiange extending substantiall in a plane perpendicular to the axis of t e stem and interlocked with said annular shoulder, the portion of said stem immediately adjacent to said iange being pressed radially inward to form a slight groove.

18. The method of manufacturing valve tappets comprising the separate forming of a disk head and a tubular stem, said head being recessed to form an annular undercut shoulder and said stem being provided at one end with an annular Haring portion initially oblique to the axis of the stern, and in' applying endwisel pressure to said members to bend said flaring portion substantially into a plane perpendicular to the axis of the stem, thereby peripherally ex anding the same into engagement with sai( undercut recess, the lower portion being expanded to a greater extent than the upper portion to fill .the undercut of the recess.

` In testimony whereof I afx my signature.

WILLIAM C. OSTERHOLM.