US1248405A - Silent self-adjusting push-rod. - Google Patents

Description

' gmsrarnnr .onirica ROBERTL. RUSSELL, F DALLAS, TEXAS, ASSIGNOR OF SEVEN-EIGHTHS T0 JAMES G.

LEDBETTER, 0F DALLAS, TEXAS..

SILENT SELF-ADJUSTING PUSH-ROD.

'To all lwhom it may concern.'

tain new and useful Improvements in Silent Self-Adjusting Push-Rods, ofwhich the following is a specification.

This invention relates to a new form of valve tappet and will here be designated as a silent self-adjusting valve *tappen The present invention pertains to that mechanical element used in connection with internal combustion engines which controls the valves of said engines and which mechanical element is known'by the name of push rod, cam slide, valve mechanism or valve tappet. g

The uses to which av device embodying the principles of this invention can be adapted are many. In any form of machine where motlon 1s transmitted through cam action, in draw rodsvand brake systems for various forms of machines where lost motion or play can advantageously be eliminated, the

v-device is highly adaptable.

The present description and illustration will correlate the-'invention with a portion of' an .engine cylinder.

The old type tappet for' automobile engines is manually adjustable and is so adjusted as to leave a slight space or clearance between the tappet and extremity of the valve stem. This space may be reduced through accurate adjustment of the parts till it isv infinitesimal in measurement; yet some space must be left to accommodate the expansion o`f parts due to the variation.'

oi the temperature in operation of the engine. The space necessarily existing be .tween tappet and valve gives rise to minute, y'et distinctively present, tapping or clicking sounds, due to the contact ofA metallic parts during the rapid reciprocation of the tappet. The tappet or push rod under the rapid lifting impulses of the cam indeed causes the tappet to be thrust or impinged against the valve stem to such a degree `as to set up a certain wearing and undesirable vibration and stress throughout the several elements which constitute the valve mechanism,a1id further causes, through wear, the clearance space to increase, after considerable time, thereby increasing the noise and other ineilineies which arise from the tapp et.

'Patented Nov.. 2'?, 19T?.

.view, the invention has relation to a certain combination and arrangement of parts, an example of which is described in the following specification, pointed out in the appended claims and illustrated in the accompanying drawing, wherein:

The iigure illustrates a portion of an engine cylinder 'in vertical cross Section, in whichfis shown the silent self-adjusting valve tappet in section.

Referring now more in particular to the drawing, the numeral 1 designates the wall of the cylinder of an engine. Only a part of the cylinder is herewith illustrated; that portion which constitutes the valve guide 2 and slidably confines the valve 3 therein. Said valve is provided -with the usual spring and its Acorrelated parts, which arrangement is adapted to keep the valve normally seated as illustrated. `lnternal combustion motors and in particular automobile engines are generally provided with a plate or housing which covers the valve mechanism and in such case a quantity of oil generally collects and stands in'the reservoir formed by said cover plate. Tn the present illustration a cover plate 4. is provided which extends from the overhang of the cylinder to the.

e of the crank case 5 of the engine, Y

mary members so arranged as to form, in I in the tappet.

t10. A groove or channel 11 is formed in the exterior periphery of the member 8.

ber 8.

Apertures 12 are provided in the member' 8, and open directly into the groove 11.- A

yplunger tappet, which consists of a tubular mem er 13 1s formed integral with an enlarged head 14. The tubular tappet plunger is provided with apertures 15, formed inthe upper extremity of the tubular portion and also inithe central or lower portion thereof. The plunger assumes the form of a piston and its several parts must closely and accurately t the bores of the tappet. The enlarged portion of the plunger is .provided with a shoulder 16. A coil spring 17 is confined upon the plunger, the extremities thereof bearing against the head of the plunger and against the shoulder within the member 8. The spring is confined in compression within the bore of the tappet and exerts an ,upward lpush on the plunger, thereby keeping said plunger in positive and continuous contact with the valve stem. The tubular plunger tappet extends a, portionof the distance into the bore/of the mem- A valve consisting of .a ball 18 backed up with a s ring 19 is confined in the lower portions o the interior of the tappet member; the said ball seating itself against the open lowen tubular extremity of the plunger tappet. AAn air passage 20 lis provided in the plunger to allow the escape of air from the interior of the tappet and allow a free assage of oil thereinto.

The usual orm of cam and shaft is illustrated in connection with the invention, and

adapted to operate the valve through the tappet."

In assembling the few parts which com prise this device a -small quantity of oil` will be poured into the smal1` 'bore of the tappet. The plunger will then' be inserted and pressure applied till the plunger settles into the positlon illustrated, which brings the shoulder 15 in close proximity to the rim of the tappet andallows the assembled device to be contained within theguide and between the cam and' valve.

lThe oil contained within the valve compartment, rises therein during the operation of the motor and will flow through the severa'l apertures of the parts and tendto fill the tubular plunger and other spaces with- The ball valve divides the interior of the tappet intoetwo oil chambers as illustrated,

within the hollow plunger is supported by the ball and will flow by the ball and replenish the lower chambers supply if the ball valve should contract from its seat.

As an incompressible Huid, such as oil, is here used, the plunger tappet is supported upon the incompressible and in a degree, inescapable oil column or' oil pocket. The oil in the lower chamber forms the lifting medium through which is transmitted to the valve the lifting impulse of the cam. In the operation of this device the revolving cam lifts the tappet. The oil being confined in the lower chamber is inescapable and directly lifts the plunger, whichplunger is already in contact with the valve stem. As the valve stem begins to lengthen under the expansion due to heat of the operating parts, the plunger tappet is itself slowly depressed and pushed downwardly into the .member 8; the oil which is in the lower chamber and beneath the plunger will slowlyy escape by the tubular piston and pass between said 'piston and the cylindrical wall Aof the member 8. This oil which is forced from the lower pocket or compartment finds lodgment in the upper compartment. When operating conditions so change as to' cause the valve stem to shorten, the spring 17 .causes the plunger to follow up the contracting valve stem. This motion of the plunger in the member 8 and upward against the valve causes the ball to contract from its seat, thereby admitting oil by the valve to the pocket below.' This owing in of the oil to thev incompressible oil pocket beneath the plunger, or the ejection of the oil therefrom means that the plunger is ex- ,.panding or contracting and susceptibly accommodating the valve in all `its variationsv This action causes the ball to unseat, ad-

mitting oil to the Vlifting pocket, thereby terminating rthe reciprocating action above described, and in ei'ect,indeed`solidiy1ng the push rod.

A'push rod of this type is si1ent, there fore more eicient in performance slnce it retenue transmits the power to the valve stem which had theretofore been absorbed at the point of contact of tappet and valve stem.

Engines provided with this type of tap-v pet will have an inherently universal valve lift, and by this is meant that every valve of the motor will lift, to an accurate degree, the same height.

Since this tappet is equivalent to a solid element interposed between the cam and the valve stem, the pressure of valve closing spring is transmitted downward through the tappet, causing said tappet to run in continuous and contiguous relation to the cam, thereby eliminating what is known as the back lash or cam slap.

An engine provided with this form of silent tappet is quieter and more efficient in operation, and longer lived, since this tappet eliminates the various inefficiencies of the type in original use.

The invention is presented as including all such changes and modifications as may properly come within the scope of the following claims.

Claims:

l. In a valve push rod for lifting the valves of an engine, the combination with a guide, a cylinder provided with a central bore slidably confined in the guide, another cylinder provided with a central bore adapted to be slidably confined within the first and larger cylinder and of a length shorter than the length of the bore of the larger cylinder, a compression spring confined upon the inner cylinder and adapted to exert a parting tendency of the cylinders, a ball valve located in the bore of the outer Cylinder and arranged to close the open end of the inner cylinder whereby oil may be admitted or excluded from the 'chamber formed by the bore at the lower end of the larger cylinder.

2. In a push rod, the combination with a guide member, of a valve tappet slidably confined withiinsaid guide, said valve tappet provided with a longitudinal bore, a plunger confined Within the boreand leaving an unfilled space below said plunger, and means for admitting liquid below the plunger.

3. In a push rod, the combination of a hollow tappet, a hollow plunger4 carried by the tappet, a liquid pocket formed beneath the hollow plunger, and a ball seated against the lower extremity of the hollow plunger.

4. In a self adjusting valve tappet, the

of the plunger cylinder, and openings formed in the members admitting liquid to the ball valve.

5. In a self-adjusting valve tappet, the combination with a guide member, of a cylinder slidably confined in said guide member, said cylinder having one extremity closed, a plunger cylinder confined within said first named cylinder, said plunger cylinder being formed hollow, with a closed extremity and open extremity, a shoulder or head formed on the plunger, a coil compression spring interposed between the shoulder or head of the plunger and cylinder, and a ball valve seated against the open extremity of the plunger cylinder, and means for passing liquid into the interior of the cylinder.

6. In a valve tappet the combination withy a guide, of a cylinder, a plunger, Said cylinder and plunger each having a closed head or extremity, the open end of theplunger vbeing inserted in the cylinder, a liquid pocket confined between the inserted plunger end and the cylinder head, said plunger provided with a liquid passage formed through said plunger, said plunger provided with an opening formed in the wall of the plunger at the upper end of said passage, a valve confined in said liquid pocket and normally closing the inserted end of said plunger, and said plunger finished to such a size asto be supported upon the liquid pocket in the lifting of its associated valve and yet allow the liquid in said pocket to slowly escape upwardly by said plunger and through the opening 1n said plunger into the interior thereof, thence down to the ball valve whereby a circulating movement of the liquid is effected when the telescoping members move one on the other.

In testimony whereof, I affix my signature in the presence of two witnesses.

RUBER'I C. RUSSELL Witnesses:

C. A. PEARCE, i M. HAMmroN.

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