US1751716A - Cushioned valve tappet - Google Patents

Description

March 25, 1930. W F, FORTH l 1,151,716

CUSHINED VALVE TAPPET Fild April 26', 192e y IHIIII II lll' 31am/nto@ @Miou/WMO I liatelnt-ed Mar. 25, A19230 d PATENT OFFICE WILLIAM F. PORTE, OF DETROIT, MICHIGAN CUSHIONED VALVE TAPPET Application led April 26,

The invention relates to cushioned valve tappets and more especially to tappets provided with fluid pressure cushioning means.

The invention contemplates, in valve op- 6 erating mechanism employing lubricated tappets, the utilization of this source of fluid for providing cushioning means for plunger elements forming a part of each tappet and which constitute the direct bearing conne:- 1o tion between the tappet and the valve stem.

By such a construction several noteworthy advantages are obtained, the principal of which, however, is that of eliminating the noise incident tothe engagement of the tap pet with the valve stem. This particular advantage is obtained because I`the cushioning means maintains the plunger element of the tappet normally projected or extended a distance 'substantially equal to the usual clearance provided between the tappet and the cam shaft so that in eiect a longitudinally resilient column is eiected between the cam shaft and the valve stem whereupon the noise incidentto the slapping engagement between the cams and the tappets is eliminated; The

amount of pressure maintained and the extent of leakage between the tappet and plunger is such that the plunger reciprocates or telescopes with the tappet V'upon each. reciprocation of the tappet so that the plunger is maintained in Contact with thevalve stem substantially continually and the objectionable noise incident to the operation of tappet valves eliminated.

The invention contemplates various other objects, advantages and novel details of construction, all o which will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein- Figure 1 is a fragmentary side elevation partly in section, of a valve operating mechanism embodying my invention, and

Figure 2 is an end elevation thereof.

Referring now particularly to the drawings wherein like reference characters indicate like parts, 1it will be noted that there is illustrated fragmentarily a valve cam shaft 10 provided with a-plurality of cams 11 equal in number to the valves to be operated, the

1926. Serial No. 104,863.

stems 12 of which are fragmentarily illustrated.

The reference character 13 indicates the tappet bearing frame in which the tappets 14 are mounted for reciprocation in the cus- 55 tomary manner by the cams 11. Each tappet 14 is provided with a longitudinal bore 15 the upper end of which is interiorly threaded for the reception of a tappet adjusting screw 16. The upper end of the tappet adjusting screw is provided with a bore 17 of reduced diameter and with a circular recess 18. Associated with the outer or upper end of each adjusting screw 16 is a plunger element 19 having a shank portion 30 which tits into the G5 bore 17 and a head portion 21 of a diameter to snugly fit the circular recess 18. The plunger element 19 is consequently sldably or reciprocally mounted in the upper end of the tappet 14 and tends to seat itself by grav- 70 ityl with the head -21 thereof resting in the bottom of the recess 18.

. The bearing frame 18 is provided with a longitudinally extending bore or passageway 22 extending past the several tappets 14 75 through which lubricating oil is supplied to the tappets, this passage-way communicating approximately at the center thereof, with a supply conduit 23 connected to a suitable fsource of lubricant supplied under pressure. S0

Thus lubricant is fed into the passage way 23 and thence laterally through the longitudinal passage-way 22 in both directions as indicated by the arrows and past the several tappets 14, Each tappet is formed with a circumferentialv recess or groove 24 communicating by one or more apertures 25, withthe interior or bore l5 of the tappet. The circumferential slot 24 is of suiicient width as to always connect with or remain in communication with the bore 22 during the reciprocation of the tappet 14. Thus, fluid under pressure, inthe present linstance lubricating oil, will be constantly supplied to the interior of each tappet. t. .95 The pressure of the lubricant within the bore of the tappet is suicient inthe idle position of the cam 11, to force plunger element 19 upwardly to the position illustrated in the drawing, in which position it bears against the lower end of valve stem 12. Lubricant within the bore 15 also escapes upwardly around the shank portion 20 of the plunger to fill the space between the head 21 and the bottom of recess 18. When subsequently the cam 11 is rotated to the other position illustrated in Figure 1 and the tappet 14 has consequently been moved in an upward direction to open the valve, the plunger element 19 will have been forced downwardlyto a position where the head 21 is seated in4 the recess 18. During this movement the fluid in the bottom of the recess 18 has been displaced by the head 21 and it has also been necessary for the lower end of the plunger 19 to displace the fluid in the bore 15 sufficiently to permit this plunger to telescope within the tappet 14. During continued rotation of the cam and its return tothe first described position, the pressure within the bore 15 of the tappet again urges the plunger upwardly. Consequently the plunger is maintained in engagement with the end of the valve stem and its. telescopic movement with reference to the tappet cushioned or checked.

Obviously the device is distinguishedb its simplicity which, however, in no wise a fects its eiciency of operation. In the type of installation with which the invention is herein shown as associated, the lubricating system already forming a part thereof, may be conveniently employed as the source of fluid pressure for cushioning the plunger of the tappet so that the device is commercially satisfactory and acceptable because it does not involve any radical rearrangement or redesigning of what now constitutes standard equipment. Obviously in other forms of valve operating mechanism the invention may however, be introduced without any serious rearrangement of the parts.

Reservation is made to make such changes in the details of construction herein illustrated as may come within the purview of the accompanying claims.

lVhat I claim as my invention is:

1. In a valve operating mechanism, a valve tappet formed with a central bore, means for constantly supplying fluid under pressure to said bore and a valve stem engaging element slidable in said bore adapted for abutting engagement with said valve tappet and cushioned by said fluid.

2. In a valve operating mechanism, a valve tappet formed with a central bore, means for constantly supplying fluid under pressure to said bore and a valve stem engaging element constituting the bearing connection between said tappet and the valve stem slidable in said bore for abutting engagement with said valve tappet and cushioned by said fluid under pressure.

3. In a valve operating mechanism, a tappet including a tubular body member, a tubular adjusting member wit-hin sa1d body member,

a plunger slidably mounted in the said tubular adjusting member and abuttingly engageable therewith, and fluid pressure means yieldably resisting abutting engagement of the said plunger with the said adjusting member.

4. In a valve operating mechanism, a tappet including a tubular body member, a tubular adjusting member threadedly mounted in one end of the said body member, a plunger slidably mounted in the end of the tubular adjusting member and abuttingly enggeable therewith, and fluid pressure means for yieldably resisting abutting engagement of the said plunger with the said tubular adjusting member.

5. In a valve operating mechanism, a cylindrical valve tappet formed with a longitudinal bore, a valve stem engaging member having a shank portion slidably received in said bore and an enlarged headed portion abuttingly engaged with the end of said tappet, and means supplying fluidpressure to said bore for cushioning said member.

6. In a valve operating mechanism, the

ycombination with a reciprocating valve stem,

of a tappet having a tubular portion supplied constantly with a lujd under pressure, and an element telescopically engaging and movf able by said fluid under pressure rela-tive to the tubular portion of said tappet, the said element being maintained in engagement with the valve stem during movement thereof and its telescopic movement with reference to the tappet being cushioned or checked by the fluid under pressure.

7. In a valve operating mechanism, the combination with a reciprocating valve stem, of a tappet havin a tubular portion, an element telescopicaly engaging and movable relative to saidtubular portion, and means for supplying constantly a fluid under pressure to the tubular portion of said tappet so that the said element will be maintained in engagement with the valve stem and the telescopic movement thereof with reference to the tappet will be cushioned or checked.

8. In a valve operating mechanism, the combination with a reciprocating valve stem, of a tappet'having a tubular portion supplied with fluid under pressure, a. valve stem engaging element telescopically arranged with respect to said tappet, a seat for said element adjustably connected to said tappet, and means for supplying fluid under pressure to the tubular portion of said tappet to maintain the element in engagement with said valve stem and to oppose and resist movement of said element upon the adjustable seat.

In testimony whereof I allix my signature. v WILLIAM F. PORTH.

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