US1481068A - ricardo - Google Patents

Description

2 Sheets-Sheet `l H. R. RICARDO VFiled April 1,'1919 faQ-ggf VALVE GEAR FOR INTERIJAL COMBUSTION ENGINES Jan. 15, 1924 Jan. 15, 1924. 1,481,068y Y H. R. RlARno l VALVE GEAR FDR INTER-NAL COMBUSTION ENGINES :med April 1, 1919 2 sheets-sneer Pluma l@ 15,1924.

UNITED STATE-s HARRY 'RALPH RICARDO, OF LONDON, ENGLAND. e

vuvn one?. non INTERNAL-convener' ENGINES.

Aivpimuon mea Apru 1, uns. semi no. 236,693.

This invention relates valve eai for internal combustion Yengines bof t espeed type having overhead valves and twin cylinders the pistons in which are connected to one and the same crank pin and has for its object to enable the valves to be operated silently and by means of simple mechanism which permits the various parts to be accessible..

According to this invention'two rocking levers are mounted on the twin cylinder heads so as toV act'on tappet levers and through them operate both inlet and both exhaust 'valves and these levers are rocked by means of eccentrics mounted on the shaft driven by gearing from the engine rcrank shaft. Four tappet levers are provided each ta pet lever actuating either an inlet, of an exliaust valve and all these levers are loosely carried on one or more rock shafts mounted ou the cylinder heads. The two rockin levers are carried on a .second rock sha t and an arm of each rocking lever actuates alternately an arm of each of two tappet levers these engaging arms acting asvvipers. The shaft on which the eccentrica are mounted is disposed transversely to the engine crank shaft, and the gearing hy which this shaft is driven from the crank shaft is arranged in some convenient manner.

Theinvention may be put into practice in various ways but the accompanying drawings illustrate by way of example one construction of, the improved valve ar as applied to a twin cylinder engine t e pistions in which are connected to a single long crank pin. In these drawinga- Figure 1 is an elevation of the engine partly in vertical section showing the improved valve gear. r i

'Fi re 2 is a plan of the `heads of the cylin ers showing the rock shafts and levers mounted thereon. V

Like letters indicate like parts the drawings. V

The cylinders A and A.' are dis osed side 'oy sidev and the pistons B B tg throughout carrie eren are connected to a singt, 4vrlank'pin C on the crank shaft D. Inletr and exhaust valves are mounted side by sdae in the heads of the two c linders and the valve spindles are upwards parallel to each other and disposed on either side of a rock shaft E suitably lcarried in bearin heads. Above and para el to this Ashaft E and n' suitable distance therefrom is car-1 ried a second shaft F. lnosely'mounted on the shaft E are two laterally projecting levers G- G each of whichhas a. second and upwardly directed arm.G. 0n the shaft l" Aarefloosely `mounted four laterally projecting levers H H and J J and the end of each of these levers lies over the end of a valve spindle K K. Each lever H H has a second and dow wardly directed arm H while each lever J' has a similarly down- I wardly directed J. The arms H J" of the levers H and J lie on either side of and in contact with the sides of the arm G2 of the lever G while the arms H2 J of the levers H and J are similarly positioned with respect to the arm Gof the lever G; The arrangement is such that as the lever (i or G is oscillated the arm G of that lever will act either on the lever arm H or the lever arm J2 with a wiper action and as a result the levers H H and J J' will be turned and caused to act on 'the valved ICK.

0n the crank shaft D is a skewtoothed wheel D' which gears with a corresponding toothed wheel L mounted ona shaft L' disposed transversely with respect to the crank sha1-tl). The shaft L carries two eccentrics M and N. A' rod M transmits motion from the eccentric M to the rocking lever G while a similar rod N' transmits motion from the eccentric N to the rocking lever G'. Thus as the shaft L' isrotatcd 'the levers Gr4 and G are rocked and the valves K and K' are actuated through the tappet levers H H and d, J.

The engine conveniently works on the four stroke cycle and the timing is so arranged that fring occurs alternately in the on the cylinder cylinders A and A thus iving an impulse' It t us becomes posvother valve on its downward stroke.

the levers H' and J.

its upward stroke operates one valve and tlIn inlet valves of the masked type are used, that is to say a valve such as described in the specification of the resent inventors prior application for` British Letters Patent No. 14,628/16, filed 14th' October, 1916, both the levers G and G can be made identical as also the 'eccentrics M and N andA their rods M and N while further the tappet levers H H and J J can all be Aformed similar. Hence the whole valve gear can bey so constructed that the parts areinterchangeable.

The shaft L can beutilizeo to drive the magneto, oil pumps and other auxiliary arts. i

The detail construction and disposition of the valve gear may be modified to suit the formation cf the engine to which it is ap lied.

n place of the tappet levers H H', J J being all mounted on one and the same rock shaft F it is in some cases preferable to provide two separate rock shafts suitably mounted, one shaft carrying the tappet levers H and J while the other shaft carries Such an arrangement to some extent simplifies the construction and arrangement of the tappet levers. What I claim as my invention and de sire to secure by Letters Patent is 1.' Mechanism for operating internalcombustion engine valves of the poppet type including two tappet levers mountedV to oscillate independentl about an axis intermediate ithe stems of t e poppet valves, each tappet lever having an arm for engaging a valve stem and a second arm at an angle thereto, each of said second arms being pro vided with a bearing surface,fthc two such bearing surfaces facing in opposite directions, and a lever mounted to oscillate about an axis parallel to the axis of the tappet levers, said lever having a wiperrarm `provided with two oppositely facing bearing surfaces to engage the bearing surfaces of the tappet levers respectively, the bearing surfaces of the wiper arm being spaced apart a distance only slightly lcss than the normal distance between the opposed bearing surfaces of the tappet levers, whereby sounds of .impact of the wiper arm on thc tappet levers are minimized.

2. Mechanism for operating internal com-V bustion engine valves of the poppet type including two tappet levers mounted to oscillate independently about an axis intermediate the stems of two poppet valves, each tappet lever having an arm for engaging a valve stem and a second arm at an angle thereto, each of said second arms being provided with an elongated bearingr surface, the two such bearing Vsurfaces facing in opposite directions, and a leverY mounted to oscillate about an axis parallel to the axis of the tappet levers, said lever having un elongated wiper arm occu ying Substantially the entire space between tlie bearing surfaces of the tappet levers and having elongated hearing Surfaces substantially coextensive with and lying closely adjacent thc corresponding bearing surfaces of the tappet levers, whereby sounds of impact of the wiper arm on the tappet levers are minimized.

In a valve gear for a high speed internal combustion. engine having overhead valves the combination of two cylinders. a lcrank shaft on which act the pistons in these two cylinders, inlet and exhaust valves in the heads of these cylinders, four tappet levers mounted on the cylinder headsV so as'V to rock about a common axis and adapted to operate respectively both inlet :inftboth Vexhaust valves, a wiper arm formed integral with nach tappet lever, two levers mounted on the cylinder heads so as to rock about a common axis which is parallel to the fulcrum axis of the tappct levers cach of these rocking levers having a wiper arm adapted to engage the wiper arms ol two tappet levers, one vpair of said tappet levers operating liol'h inlet valves and the .other pair lioth outlet valves, tivo eccentrica mounted on a shaft which is disposed transversel to the engine rrnrik shafl, rods connecting t :use ceceni ries respectively to the tivo rocking lovers, and gearing lictwcen the Icrank shaft :1nd the transverse shaft as set'forth.

In testimony whereof l have signed my name to the s cilication. y

HA `Y RALPH RICARDO.

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