US1757721A - Tappet - Google Patents

Description

E. R. KLEMM, JR 1,757,721

May 6, 1930.

TAPPET Filed Sept. 10. 1928 Patented May 6, 1930 PATENT OFFICE EMIL B. KLEIN, 1B,, OF CHICAGO, ILLINOIS I Turns:

Application filed ember 10,1928. Serial no. 805,069.

.My invention relates to improvements in tappets and moreparticularly it relates to tappets which are operable to actuate a valve or other reciprocally movable element with 5 which the tappet has'end contact. .A- well known use for such tappets is that of 'functioning as a push rod for a valve seated immediately above the tappet and in vertical alignment therewith'although such tappets may be used in other capacities and positions.

A cam which is operatively connectedwith the lower end of thetappet imparts longitudinal movement thereto and brings the tappet into end contact with the stem of the 1 valve, momentarily unseating the valve. The upper end of the tappet projects from a guide in which it is mounted. and longitudinally movable. The upper projecting end of the tappet is preferably spaced from one thirty- 0 second to one sixtyfourth of an inch away from the adjacent end of the valve stem, such spacing being called fvalve clearance or air gap by those versed in the art. The abrasion resulting from contact of the tappet with the lower end of the valve stem and with the cam in time shortens the tappet sufiicientl that the valve clearance or air gap excee s one thirty-second of an inch, which is the maximum space at which the tappet functions properly. If the air gap exceeds'one' thirt second of an inch the valve will close too ear y and open too late, resulting in uneven running and general lowering of efiiciency, accompaniedby undesirable noises or knocking of the parts. j

When the air gap for any reason exceeds the maximum allowable of one thirty-second. of an inch satisfactor operation requires either that the parts, e lengthened or replaced. Replacement of the'tappet at such frequent intervals as is required for normal use is undesirable because of the time reilfired and the expense. incidentalthereto.

' y provision for lengthenin the tappet which requires for its accomplis ment that it be removed from its mounting is undesirable for the same reasons. I am aware that many types of tappets are constructed and mounted in such a' way as to be adjustable to "compensate for shortening occasioned by use without removing the tappets from their mountings. Such adjustments usually take the form oi a lock nut and screw or other similar device, and all such devices require that the adjusting end project from the tappet guide-a considerable amount. For tappets whose maximum projection above their guide is one-quarter to three-eighths of an. inch, as is the case with the engine of the Ford car, there is insufiicient room for adjust ment of this character. The Ford tappet is constructed with no provision for adjustment, and the instruction charts descriptive of such 'tappets frequently contains the statement that when the push rods (tappcts) become worn it is best to replace with new ones. Because ofthe loss of time and the expense incident to replacement of such tappets, the y are in practice frequently continued in use when worn beyond the proper valve clearance or air gap space, with the resulting knocking noise and loss of efiiciency, and it is the primary object of'the invention to provide a tappet or push rod which is adjustable without removal from its mounting tocompensate for shortening due to abrasion and which is adapted for use with a Ford engine or other engines .havin tappets. which project only slightly from t e guide in which it is mounted.

An object isthe provision of means wherebyv the valve clearance of engines of the class described may bev easily adjusted and maintained substantially constant over a long period of use.

Still another object is the provision of means whereby the period of usefulness of tappets of the class described may be increased.

Many other objects and advantages of the construction herein shown and described will be obvious to-those' skilled in the art from the disclosure herein given. 7

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the claims. I

In the drawings, wherein like reference,

characters indicate like or corresponding parts g Fig. 1 is a sectional view through a tappet equipped with one form of the device of my invention;

Fig. 2 is a plan view of the tappet shown in Fig. 1;

Fig. 3 is a sectional view along the line 33 of Fig. 1;

Fig. 4 is a sectional view of another embodiment of the invention;

Fig. 5 is a sectional view of still another embodiment of the invention; and

Fig. 6 is a perspective view ofopen end of the main body portion of the tappet.

Referring now to the drawings, wherein I have illustrated several embodiments of my invention, the numeral 10 designates a tappet mounted in a guide 11. The guide 11 is a portion of an engine of an automobile or the like in which the tappet is longitudinally movable. The lower end of the tappet is provided with an expanded portion 12 with which a cam 13 operatively engages to impart longitudinal motion to the tappet. The upper end of the tappet 10 is shown as spaced slightly away from a valve stem 14;, this space being called the air gap or valve clearance. Rotation of the cam 13 brings the end of the tappet into contact with the stem 14 and moves the stem 14 vertically thereby unseating the valve (not shown). It is obvious that continued operation of the parts will result in abrasion and a resultant shortening of the tappet 10. This shortening will increase the air gap or valve clearance between the end of the tappet and the end of the stem 14. The distance from the top of the guide 11 to the end of the tappet being limited to three-eighths of an inch and for the purpose of providing longitudinal adjustment of the tappet 10 in such limited space, I have provided a cap 15 which has a stem 16 projecting downwardly through a bore 17 in the main body portion of the tappet. The cap 15 is low and utilizes only a portion of the limited projecting end of the tappet of which it forms a part. The lower edge of the cap 15 is provided with a plurality of serrations 18 which fit corresponding serrations 18 on the main body of the tappet. The serrations 18 are relatively small, and are correspondinglyv stepped upwardly on opposite sides, the difference in elevation of adjacent serrations being preferably not more than one sixty-fourth of an inch. The general direction of the opposite semi-circumferential edges is that of similarly sloping spirals and the serrations take a general- 1y radial direction. A socket 20 in the wall of the guide 11 provides" access to acup screw 21 which is normally threaded into engagement with the stem 16 to hold the cap 15 against movement relative to the main body of the stem. When the tappet needs adjustment, the screw 21 is loosened by means of a wrench inserted in the socket 20. The cap 15 is then lifted and turned in an anti-clockwise direction, the width of one serration or if the abrasion of the parts has been exces sive the shift may be made through two or more serrations. The screw 21 is then tightened and the cap thereby held in adjusted position against possibility of movement until further ustment becomes necessary when the operation can be repeated. This adjusting operation may be repeated until the cap has been rotated through substantially onefourth a circumference.

An alternative form, of my invention is disclosed in Fig. 4 where the main body portion of the tappet 22 is provided with a cap 23, the tappet and cap being connected by means of a plurality of serrations 18 similarly arranged and positioned as in Fig. 1. The cap 23 is held in seated position by a tensile spiral spring 24: which is mounted in a bore 35 formed in the body of the tappet. The spring 24.- is' fastened at its upper end to a boss 37 which forms part of a stem 36 extending downwardly from the cap 23. At the lower end the spring 24 is connected with a rivet or pin 25.

The spring 24 is so formed that adjustment of the. cap 23, by turning in anti-clockwise direction, increases the resistance of the spring. The sprin 2% permits the cap to be lifted and turned sufiiciently to accomplish the required adjustment and then functions to hold 7 the cap securely in place.

In Fig. 5 I have shown still another embodiment of my invention, inwhich the tappet 30 takes'the same general form as that of the tappet 10. The main body portion of this tappet 30 contains a relatively large bore 38 into which a member 39 having a cap31 is threaded. A stem 32 projects downwardly from the member 39 into the small bore 33. The cap 31 and member 39 are held firmly in adjusted position by a cup screw 34: which is similar in construction and operation to the screw 21. The length of the tappet 30 is changed by loosening the screw 34; and threading the member 39 in the desired direction. A thin, flat wrench capable of insertion in a limited space may be used for this purpose.

Each of the caps 15', 23, and 31 are recessed to receive a tight fitting washer or disk 40. The disk 40 is constructed of tough nonmetallic material which serves as a cushion and minimizes the noise that would otherwise result from the impact of the tappet with the valve stem 14.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction,

' means adapted to hold the cap member seated.

arrangement and combination of parts herein shown and described or uses mentioned.

\Vhat I claim as new and desire to by Letters Patent is:

1. A tappct comprising a cylindrical shaped main member open at one end and a relatively shallow cap member seated on the open end of the main member for the purpose described, one semi-circumferential segment of the open end face of the main member being serrated and inclined to form a spiral and the other segment of the end face being similarly serrated and spiralled, said cap member being serrated and spiralled to lit the open end of the main member and means adapted to hold the cap member seated on the main member.

2. A tappet comprising a cylindrical main member open at one end, arelatively shallow cap member seated on the open end of the main member for the purpose described, and

secure on the main member, one semicircumferential segment of the open end face of the main member being inclined to form a spiral and ha -'ing a plurality of similar radially extending serrations formed therein and the opposite semi-circumferential segment of said face being similarly serrated and spiralled. said cap member being oppositely spirallecl and serrated similarly to said main member whereby the cap can be seated in a plurality of positions on said main member.

3. A tappet comprising a cylindrical shaped main member open at one end and a relatively shallow cap member seated on the open end of the main body portion for the purpose described, one semi-circumferential segment of the end face of the main member being serrated and inclined to form a spiral and the other segment of the end face being similarly serrated and spiralled, said cap member being serrated and spiralled to fit the open end of the main member and means adapted to hold the cap member seated on the main member, said means comprising a stem projecting from the cap member into the main member and a screw mounted in the Wall of said main member and operable to engage said stem.

4. A tappet comprising a cylindrical main member open at one end, a relatively shallow cap member seated on the open end of the main member for the purpose described and means adapted to hold the cap member seated on the main member comprising a stem projecting from the cap member into said cylindrical member and a screw mounted in the wall of said main member in operative engagement with the stem, one semi-circumferential segment of the open end face main member being inclined to form a spiral and having a plurality of similar radially extending serrations formed therein and the opposite semi-circumferential segment of said face being" similarly serrated and spiralled,

said cap member being oppositely spiralled and similarly serrated to said main member whereby the cam can be seated in a plurality of positions on said main member.

5. A tappet, a; guide in which the tappet is longitudinally movable, a cam operatively connected with one end of the tappet, the other end of the 'tappet projecting slightly from the guide, the tappet comprising a cylindrical main member open at said projecting end and a relatively shallow cap member seated on the open end of the main member for the purpose described, one semi-circumferential segment of the open end face of the main member being serrated and inclined to form a spiral and the other segment of the end face being similarly serrated and s iralled to fit the open end of the main inem er, and means adapted to hold the cap member seated on the main member.

6. A tappet, a guide in which the tappet I the cap member can be seated in a plurality of positions on said main member.

7. A tappet, a guide in which the tappet is longitudinally movable, a cam operatively connected with one end of the tappet, the other end of the tappet projecting slightly from the guide, the tappet comprising a cylindrical main member open at said projecting end, one semi-circumferential segment of the open end face of the main member being inclined to form a spiral and having a plurality of similar radially extending serrations formed therein and the .opposite semicircumferentia-l segment of said face beina similarly serrated and spiralled, said cap member being oppositely spiralled and serrated similarly to said main member whereby the cap member can be seated in a plurality of positions on said main member and means adapted to holdthe cap member in seated position.

8. A tappet comprising a cylindrically shaped main member open at one end and a relatively shallow cap member seated on the open end of the main member forthe purpose described, one semi-circumferential segment of the open end face of the main member being serrated and inclined to form a spiral, and the other segment of the end face being similarly serrated and spiralled, said cap member being serrated and spiralled to fit the open end of the main member, said cooperating serrated ends comprising alternate inclined and longitudinally extending faces permitting rotation of the cap member in sliding contactwith the main member in only one direction, and means adapted to hold the ca, member-sea ted on the main member. 10 testimonyvwhereof, I have hereunto signed my name.

- Em R. KLEMM, JR.

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