US1408781A - Valve gear for internal-combustion engines - Google Patents

Description

E. S. SEWELL.

vALvE GEAR Foa INTERNAL coMBusTloN ENGINES;

APPLICATION HLED MPL10. |920.

` Patentd Mar. 7, 1922.

PATENT OFFICE.

EDGAR SHERMAN SEWELL, OF HARTFORD, tf1ONNECTIFCUT.

VALVE GEAR FOR INTERNAL-COMBUSTION ENGINES.

Application led November 10, 1920.

To all 'whom t may concern Be it known that l. EDGAR S. Suivent.. a citizen of the United States. residing at Hartford. in the county of Hartford and .Q-tete of Connecticut. have invented certain ne v and useful improvements in Valve iairs for Intemal-Combustion Engines. of which the following is a specification.

This invention relates to valve gears for internafcombustion engines, and the primary chiect duf the present invention is to provide'an improvei means for positively opening and for positively closing valves of the poppet type in internal combustion engines` whereby the sticking of the valves during the closing movement thereof from an cause whatsoever' is pievented.

lin the operation of internal combustion engines. especially of the Diesel type. a great deal of trouble is often encountered due to the retarding of the valves durin;r the closing;r movement.` caused by bindinpr between the valve stems and their guidesl when theso parts become overheated. Many attempts have been made to positively scat the valve. but these devices have not been perfected sufficiently to warrant th(` adoption thereof. It is therefore another object of the inven tion to provide a means for positivel seating the valves of internal combustion en gines. which is of exceptionally simple and durable construction, and which will perform its function in a positive and silent manner` and in which all lost motion between the valve and the operating mechanism is eliminated.

A further object of the invention is to provide a pair of cams for actin#r upon the rocker arm of the poppet valve, the rocker arm having independent rollers for engaging the cams, one of the rollers being resiliently mounted so as to eliminate all lost motion between the valve and the operating cams.

lith these and other objects in view. the invention consists 1n. the novel construction, arrangement and formation of parts as will be hereinafter more specifically described` claimed and illustrated in the accompanyying drawing. formingr a part of this specification, in which drawings:

vFigure l is a fragmentary elevation, partly in section. of an interna-l combustion engine, showing the improved valve operating means incorporated therewith.

Figure 2 is a to plan view of the rocker arm employed in tV e valve operating means,

Specification of Letters Patent.

Patented Mar. '7, 1922.

serial No. 423,110.

the valve stem being shown in connection therewith and in section.

Figure Il is a fragmentary enlarged side elevation of the rocker arm partly in section showing the means of adjustin; r the resilientl v mounted portion thereof, and

Figure Je is an enlarged fragmentary vertical section through the adjustingr nut employcd for adjustiiucr the position of the roi-Iter arm in relation to the valve stem.

Referring to the d rawings in detail, wherein similar reference -characters designate corresponding parts throughout the several views. the letter A indicates an internal combustion engine. B. a puppet valve of the ordinary construction. and the improved operating means therefor.

The internal combustion engine A may he of the usual or any preferred construction und is provided with a valve port 5 on which thc poppet valve B is adapted to scat.

The poppet valve B is of the ordinary construction, and the stem 6 thereof extends slidably through a guide 7 as in the ordinary construction. The upper outer end of the stem protrudes above the engine and is externally threaded as at 8 for the reception of the adjusting nuts 9 and 9', the purpose ol' which will be hereinafter more specifically described.

The valve gear operating mechanism C includes a rocker arm 10 which is mounted intermediate its ends upon a suitable shaft 1l. which is in turn carried by brackets 12 carried by the engine in any preferred manner. The inner end of the rocker arm 10 is bifurcated as at 13 and provided with the hearing heads of circular shape 14 and these bearing heads 14 are adapted to engage between the adjusting nuts 9 and 9 as clearly shown in Figure 1 of the drawings. The adjusting nut 9 includes a relatively long cylindrical wear portion 15.y which the heads l-l are adapted to normally embrace. The upper surface of the rocker arm 10 at a point inward ofthehead 14 is provided with a cut out portion 1G in which is fitted a stub arm 17 which is formed of spring steel or the like. This arm 17 is connected to the upper end of the rocker arm by means of screws 18. The outer end of the arms 10 and 17 have rollers 20 and 21 respectively carried thereby and these rollers are adapted to engage cams 22 and 23 which are arranged in superposed relation. The cam 22 is ofthe usual conigu` ration employed for moving poppet valves ofi1 of their seats, and is keyed or otherwise secured to a lower shaft 24 which is mounted in a suitable bearing carried by a bracket 25. This bracket 25 is secured to the internal combustion engine in any preferred manner. The upper cam Z3 is adapted to engage the upper roller 2l carried by the stub arm l? and has the substantially flat fares 2G formed thereon. This cam 23 is keyed or otherwise secured to an upper shaft 27, which is also rotatably mounted in suitable bearings carried by the bracket 25. These shafts .24 and 27 are operatively eon nected together by means ot' spur gears 30. One of these spur gears 30 is positively driven by the crank shaft (not shown) of the engine A, and it can he seen that upon operation of one shaft, the other shaft will be operated synchronously therewith.

In order to adjust the tension of the arm 1T so as to cause the proper seating of the valve B an adjusting screw 3l is carried by the rocker arm 1() and this screw is adapted to engage the lower surface of the spring stub arm l?. A suitable lock nut 82 is threaded on the set screw so as to hold the same in a preferred adjusted position.

In operation of the improved valve gear the cam 22 will act to rock the arm l0 and thus move the valve B olf of its seat and the cam 23 will act on the upper roller 2l and tend to move and to hold the valve on its seat after the opening thereof. Owing to the resilient nature of the stub arm 17 all lost motion between the cam and rollers is eliminated, and the arm 1T provides suficient tension so as to resiliently hold the valve on its seat and it can be seen that by adjusting the nuts 9 and 9 and setV screw 31, the valve can be set to seat at any preferred tension.

From the foregoing description, it can be seen that exceptionally simple and durable means has been provided for positively moving a valve from off of its seat, and for ositively movin and holding a valve on its seat in which a l lost motion is eliminated.

Changes in details may be made without departing from the spirit or scope of this invention; but, v

I claim:

1. In a valve operating mechanism, the combination with a valve having a stem, of a rocking lever, means connecting one end of the rocking lever to the valve stem, a resilient stub arm secured to the other end of the rocking lever, rollers carried by the free ends of the 'rocking arms and the resilient stub arm, the rollers being arranged in superposed relation, a pair of superposed cams arranged to engage` the opposite sides of the rollers, means for synchronously operating the cams, said resilient stub arm permitting a limited movement between the rollers.

2. '.In a valve operating mechanism, the combination with a poppet valve having a stein, of a rocking lever, means formed on one end of the lever for engaging the valve stem, independent rollers carried by the opposite end of the lever, a rotatable cam for engaging each one of said rollers, means for synchronously operating the cams, and mea-ns for resilient-ly mounting one of said rollers.

3. In a. valve operating mechanism, the combination with a valve having a stem and a rocking lever, a yoke formed on one end of the lever engaging the valve stem, independent upper` and lower rollers carried by the opposite end of the lever, a cam arrange to engage one of the rollers for rocking the lever to move th. valve from its seat, a second cam arranged to engage the other roller to move the valve on its seat, means for synchronously operating the cams, and means for resiliently mounting the roller engaged by the cam for moving and holding the valve on its seat.

4. In a valve operating mechanism, the combinationwith a valve having a stem, o a rocking ing one end of the lever to the valve stem, a resilient stub arm secured to the u per end of the rocking arm, rollers carried by the free ends of the rocking arm 'and the stub arm, means for adjusting the tension of said resilient stub arm, superposed cams arranged to engage the rollers, and means for synchronously operating the cams.

5. In a valve operatin mechanism, the combination with a valve aving a stem, of a rocking lever, means adjustably connecting one end of the lever to the ,valve stem, a resilient stub arm secured at its inner en to said rocking arm, independent rollers carried by the outer ends of the rocking arm and the stub arm, means for adjusting the tension of said stub arm, a pair of superosed shafts, independent cams carried by the shafts arranged to engage the rollers, intermeshing spur gears keyed to said shafts, and means for rotating one of sadshafts.

EDGAR SHERMAN sEWELL f l0 lever, means operatively connect-

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