US1722821A

US1722821A - Valve-operating mechanism

Info

Publication number: US1722821A
Application number: US168206A
Authority: US
Inventors: Nutt Arthur
Original assignee: Curtiss Aeroplane and Motor Corp
Current assignee: Curtiss Aeroplane and Motor Corp
Priority date: 1927-02-14
Filing date: 1927-02-14
Publication date: 1929-07-30
Anticipated expiration: 1946-07-30

Description

July so, 1929. A. NUTT 1,722,821

\ALVE OPERATING MECHANISM Filed Feb. 14, 1927 2 She ets-"Sheet 1 I INVENTOR AETHUR Hu'rr.

' ATTORNEC 'July 30, 1929.

A. NYUTTV' v 1,722,821

VALVE OPERATING MECHANI SM Filed Feb. 14, 1927 2 Sheets-Sheet 2 nvvszvr ARTHUR Nu'r A TTORNEY Patented July 30, 1929.

UNITED STATES PATENT OFFICE.

ARTHUR norm, or KENMQRE, NEW YORK, nssrcnon T cun'riss AEROILANE a moron COMPANY, me, A CORPORATION or New YORK.

VALVE-OPERATIN G MECHANISM.

Application filed February 14, 1927. Serial No; 168,206.

My invention relates to internal combustion motors and is more particularly concerned with the valve operating mechanism thereof.

-Many types of racing motors, as well as a large number of aeronautical motors, are

' characterized by the provision of two or more intake valves and two or more exhaust valves per motor cylinder, such multiple valve equipment being conducive to a greater motor efiiciency and a more rapid and better distribution of both the incoming and the spentfuel or gas. In using a multiple number of valves per motor cylinder, it has been the practice heretofore to either cross-port one intake and one exhaust valve of each pair of valves and use a single cam shaft,-or its equivalent, or,

where cross-porting is avoided, to use two cam shafts for each bloc or bank of cylinders.

Regardless of the construction employed the wei ht and complexity of the valve operating mec anism is excessive.

The particular object of the present inven-.

tion is to so organize the valve operating mechanism of a multi-cylinder internal combustion motor having two or more intake and two'or more exhaust valves per motor cylinder as to avoid the necessity of cross-porting the valves and yet, in the preferred embodiment of the invention, provldc for the proper operation thereof thru the use of a single cam shaft. Instead of arranging the intake and exhaust valves alternately at opposite sides of the plane of the cylinder axes and extending valve tappets crosswise the cylinder bank, all of the intake valves are arranged at one side of said plane and all of the exhaust valves are arranged at the opposite side there-' of. This arrangement coupled with the fact 40 that the valve tappets of the corresponding valves of each motor cylinder extend lengthwise the motor and are offset laterally, enables me to use, with excellent results, a single cam shaft or its equivalent, said shaft being preferably extended longitudinally of the motor in the plane of the cylinder axes. Thus organized, the construction of the valve operating mechanism is much simplified and the weight of the motor, considered in its entirety, many pounds reduced, e. g., a consideration of vast importance in the desi and construction of motors for use in airraft.

A further object of the invention is to so form the laterally olfset head portions of the valve tappets as to admit of the interchangeab1l1ty thereof; such interchangeability resulting from a head formation in which the arms of the head portions of the valve tappets are of unequal length as measured, in each instance, from the offset;

A still further object of the invention is to reduce the projected area of an internal combustion motor, and especially an aeronautical internal combustion motor, by interpolating in the driving connection for the overhead cam shaft suitable gearing so disposed in its relation to the axis of the cam shaft as to avoid the necessity of'mounting at the end thereof a relatively large bevel gear.

Otherfobjects, advantages and improved results will be hereinafter pointed out.

In the drawings, wherein like reference characters denote like or corresponding parts,

Fig. l is a, plan View of one of the cylinders.

of a 'multi-cylinder internal combustion motor having four valvesper cylinder, and in which a single cam shaft is provided for the proper operation of the total number of valves;

Fig. 2 is a side elevation of the structure illustrated in Fig. 1; Fig. 3 is a vertical sectional view;

Fig. 4 is a diagrammatic illustration of a bank of engine cylinders showing the relation of the multiple valve tappets and the single operating cam shaft;

Fig. 5 is a perspective view of one ofthe valve tappets; i

Fig. 6 is a view similar to Fig. 2 illustrating a-modified cam shaft drive;

Fig. 7 is a vertical sectional viewof the structure illustrated in Fig. 6;

Fig. 8 is a plan view of a further modification;

Fig. 9 is a longitudinal vertical sectional view of the modification of Fig. 8; and

Fig. 10 is a transverse sectional view of 'altho the invention is especially designed for use in aeronautical motors wherein a plural number of cylinders are provided, said cylinders being preferably in l1ne whether or not one, two or more banks of cylinders are provided. The engine cylinders are designated as 10. Each cylinder is provided with two intake valves 11 and two exhaust valves 12, the valve stems of each being carried thru the cylinder head casting to project thereabove or therebeyond as shown. For each corresponding pair of valvesa single valve tappet is provided, the, valve tap ts for the intake valves 11 beingdesignate as 14 andthe valve .tappets for the exhaust valves 12 being designated as 13.-

Said valve tappets

13 and 14, orrather the head portions thereof,

. extend longitudinally of the motor or cylinder bank inlconn'ection' with which they are used, the head portlons of the intake valve tappets 14 being preferably disposed in longitudinal alignment at one side of the plane of the cylinder axes and the head portions of the exhaust valve tappets 13 being similarly disposed at the opposite side thereof. Such a valvetappet arran ement is advantageous in that the necessity or cross-p0rting is avoid- .ed. Heretofore, in so far as I am aware,

. the cylinder axes to the end that all intake valve ports may terminate at one side of the bank of cylinders and all exhaust valve ports at the opposite side thereof; By disposing the valves of the motor as herein illustrated,

lent is made to function as the means of oper-.

this objectionable cross-porting feature is overcome.

Not only is cross-porting avoided as previously mentioned, but in the present invention, thru an improved ta pet construction, a single operating cam sha 15 or its equivaating the total number of valves. The valve tappets 13-and 14' are of identical construction. Each includes a stem or shank portion to portion; (see ig. 5) are of unequal length as- I measured from the offset, to the end that the o 16, an offset portion 17, and a head portion 18,

the latter belng formed at the end of the offs set to span or bridge the distance between correspondmvalves. The arms of the

head valve tappets

13 and 14 may be interchangeable. Such interchangeability is especially desirable as a service feature in that it admits of the use of a single type of valve tappet as arepl'acement' part whether intended for use in connection with the exhaust valves or the intake valves of the motor.

Said valve tapp'ets, as intimated, are of the T-type. The shank portions thereof engage in guides 19'fastened to the cylinder. heads,

whereas the head ortions 18, instead of extending crosswise t e motor, as heretofore,ex-

tend lengthwise thereof inthemanner indicated. Thus organized a single cam shaft, or its equivalent, if extended longitudinall of the cylinder bank as shown, is made to unction as the operating means for the total number of valves. The cams 20 0f the cam shaft act directly upon enlargements 21' formed on thestems and engaging in depressions 22 formed inltihe cylinder head, seat the valves automatica y.

To operate the cam sha-ft, it is the usual practice to provide at one end thereof a relatively large bevel gear, such gear (see Figs. 6 and 7) being usually mounted directly upon the cam shaft. A gear thus mounted, ,especially in aeronautical motors, is found to be ob ectionable because of the increased area which it offers in flight. To reduce the projected area of the motor, suchgea-r, desig-' nated as 22, is dropped down to an extent best illustrated in Figs. 2 and- 3, wherein it will be observed that the gear lies wholly.

within the plane of the forward bearing 23 provided for the cam shaft 15. Said bearing 23, beneath the cam shaft 15, also supports a stub shaft 24 upon which a spur gear 25 is mounted. Said gear 25 is in mesh with a similar gear 26 mounted on the cam shaft. Preferably the bevel gear 22' and the spur gear 25 are in line,- the former (see Fig. 2) being driven thru a bevel pinion 26 mountedon a drive shaft27 eared to the crank shaft of the motor and riven therefrom by any suitable means.v

In the modification of Figs. 6 and 7 the valve arrangement and the valve operating mechanism are the same as previously described. The intermediate gear 25 of the cam shaft, however, is omitted. In said Figs. 6 1

and 7 the driving pinion for the cam shaft gear engages the bevel gear, said last mentioned gear being directly mounted upon the cam shaft. Thus organized, a slight reduction in Weight is obtained altho theprojected area of the motor remains the same.

In the modification of Figs. 8 to 10, inclusive, a geared down driveis obtained thru the use of an intermediate gear 30, which gear 30 is in mesh with two spur gears 31 mounted respectively upon the ends of two cam shafts 32. In this modification, altho the projected area of the motor is reduced, it is necessary, for the PI'QPGIL operation of the vvalves, that two cam shafts be provided for each bank or bloc of cylinders. 1 While I have described my inventionin detail in its present preferred embodiment, it will be obvious to those skilled in the art after understanding my invention, that various changes and modifications may be made scope thereof. I aim in the appended claims to cover all such modifications and changes.

What I claim is:

1. In valve operating mechanism for internal combustion motors, a pair of intake valves and a pair of exhaust valves for each motor cylinder, said intake valves being dis-- posed at one side of a plane passing thru the axes of the motor cylinders and said exhaust valves being disposed at the opposite side of said plane, a reciprocating valve tappet for each pair of valves, and devices movable about an axis common to the total number thereof-to actuate said tappets.

'2. In valve operating mechanism for internal combustion motors, a pair of intake valves and a pair of exhaust valves for each motor cylinder, said intake valves being disposed at one side of a plane passing thru the axes of the motor cylinders and said exhaust valves being disposed at the opposite side of said plane, a valve tappet for each pair of valves, each valve tappet including a reciproeating stem portion and a laterally offset head portion rigid in its relation to said stem portion, said head portions being likewise disposed respectively at opposite sides of said plane, and means operable to actuate said tappets.

3. In valve operating mechanism for internal combustion motors, a pair of intake valves and a pair of exhaust valves for each motor cylinder, the total number of intake valves being disposed overhead and at one" side of a plane passing thru the axes of the motor cylinders and the total number of exhaust valves being disposed overhead and common to the corresponding valves of each cylinder, and mechanism operable to actuate said tappets.

4. In valve operating mechanism for internal combustion motors, a pair of intake valvesand a pair of exhaust valves for each motor cylinder, said intake valves being disposed at the outer cylinder ends and on one side of a plane passing thru the axes of the motor cylinders and said exhaust valves being disposed at the outer cylinder ends and on the opposite side of said plane, an overhead valve-tappet for each pair of'valves, each valv'e tappet including a stem portion,

and a laterally offset head portion, said head posed at one side of a plane passing thru the axes of the motor cylinders and said exhaust said stem portions being aligned in a plane common to the total number thereof and said head portions being aligned in groups dis-' posed respectively at opposite sides of said plane, and means operable to actuate said tappets.

6. In valve operating mechanism for internal combustion motors, a pair of intake valves and a pair of exhaust valves for each motor cylinder, said intake valves being disposed at one side of a plane passing thru the axes of the motor cylinders and said exhaust valves being disposed at the opposite side of said plane, a valve tappet for each pair of valves, each valve tappet including a stem portion and a laterally offset head portion, said stem portions being aligned in a plane common to the total number thereof and said head portions being aligned in groups disposed respectivel atopposite sides of said plane, and devices or actuating said tappets movable about an axis common to the total number thereof and engaging said tappets in the set with respect to its stem, and said headportions, with respect to each other, being oppositely laterally ofi' -set and being disposed respectively at opposite sides of a plane passing thru the axis of said cylinder, and means disposed in the plane of said axis for actuating the respective tappets.

8. Valve operating mechanism for multicylinder internal combustion motors including a pair of T-tappets for each motorcylinder, each tappet having its head portion offset laterally with respect to its stem, said stem portions, in each instance, being aligned and said head portions being oppositely offset to lie respectively at opposite sides of a plane passing thru the axes of said cylinders, and mechanism operable to actuate said tappets. Y

9. Valve operating mechanism for internal combustion motors including a pair of valve tappets having oppositely laterall oilset head portions disposed respective y; at opposite sides of a plane passing thru the axis of said cylinder, said tappets being interchangeable, and mechanism operable to actuate said tappets. 10. Valve operating mechanism for multicylinder internal combustion motors including a pair of T-tappets for each motor cylinder, each T-tappet having its head portion ofiset laterally with respect to its stem, said head portions being disposed respectively at opposite sides of a plane passing thru the said cam shaft being disposed in said a .mentioned plane.

T-tappets for each cylinder, each T-tapp axes of said cylinders, guides for the valve tappet stems, and a single cam shaft operable to actuate the total-number of valve tappets,

ove

1 1. Valve operating mechanism for multicylmder internal combustion motors includmg two or more intake valves and two or more exhaust valves for each motor cylinder,

said intake valves being disposed at one side of a plane passing thru the axes of said cylinders and said exhaust valves being disposed on the opposite side of said plane, a pair of et having its head portion oflset laterally with respect to its stem, and said head portions being disposed respectively on opposite sides of said plane whereby a single valve tappet is adapted to actuate a pair of valves, and an operating means so related to the total number of valve tappets as to engage the olfset portions thereof in the plane of the valve tappet stems.

12. A T-tappet for internal combustion motors comprising a stem portion and a head portion, said head portion, as measured from said stem portion, including a long arm and a short arm respectively.

In testimony whereof I hereunto aflix my signature.

ARTHUR NUTT..