US3045657A

US3045657A - Valve operating means

Info

Publication number: US3045657A
Application number: US828895A
Authority: US
Inventors: Achilles C Sampietro
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1959-07-22
Filing date: 1959-07-22
Publication date: 1962-07-24
Anticipated expiration: 1979-07-24

Description

July 24, 1962 A. c. SAMPIETRO VALVE OPERATING MEANS 4 Sheets-Sheet 1 Filed July 22, 1959 r 9 H. 6 3 1 1 9 6 M 3 3 6 9 I 9 4 6 7 u 1 2 u 4 1. A. 5 o I. 8 0 3 1 2 9 ,92 H 8 8 9 I Z 8 I I 1 9 J w .2 6 2 .8 H Z 8 v m m a n I. 2 4L Z m B 2 3 M1 5 1 .1 3 m 6 in u. 1 5 w & Z l 1 W 7 a m u x z 7 4 u I 9 9 M a 9 4. 4 4 (L 4!. 1 O 3 7 M F H 1 .M. M a n nn [17 ye 171 UP Zc/Zz'llas C jampv'cira July 24, 1962 A.-C. SAMPIETRO 3,045,657

VALVE OPERATING MEANS Filed July 22, 1959 I 4 Sheets-Sheet 2 I 3 IHl/EIJIUF flafiv'l'les C fampvefra July 24, 1962 A. c. SAMPIETRO 3,045,657

VALVE OPERATING MEANS Filed July 22, 1959 4 Sheets-Sheet 4 5 I 17 V53 17 I 13 r dab/Z65 C Jam $1217 0 @A -HH E.

United States Patent G a Filed July 22, 1959, Ser. No. 828,895 15 Claims. (Cl. 12390) The present invention relates to improvements in mechanism for operating valves of an internal combustion engine. The invention particularly relates to a mechanism wherein a single cam opens both the inlet and exhaust valves.

The invention contemplates provision of a valve operating mechanism in an internal combustion engine having overhead inlet and exhaust valves operated by rocker arms which are pivotally supported by a mechanism which may be provided with means to adjust the lash and to take up wear. Separate rocker arms extend laterally outwardly to engage and operate the intake and exhaust valves and are provided with followers at their inner ends which engage a cam means on a single cam shaft for operating both of the rocker arms to operate both the inlet and exhaust valves in the right sequence and at the right time in the cycle.

An object of the invention is to provide an improved valve gear for an internal combustion engine which is substantially reduced in cost and in number of parts, eliminating the need for tappets and pushrods and reducing the number of cam shafts required.

Another object of the invention is to provide an improved fulcrum support for an engine valve rocker arm which will remove the lash from the valve linkage. An object is to provide an improved fulcrum support to adjust the lash and take up wear in a valve operating linkage utilizing cam means on a single cam shaft, and which will function to hold the valves closed during non-operating periods and during engine operating periods when the valves are not opened by the cam.

A further object of the invention is to provide an improved connection between a rocker arm and a poppet valve for rotating the valve during engine operation.

Another object of the invention is to provide an improved valve linkage arrangement for an overhead valve assembly in an internal combustion engine driven by a single cam shaft which is well suited to operation with or without valve lash adjustment mechanism and is suited to operation in engines having more than one bank of cylinders.

Other objects and advantages will become more apparent with the teaching of the principles of the inven tion in the disclosure of the preferred embodiments thereof in the specification, claims and drawings in which:

FIGURE 1 is a vertical sectional view taken through a cylinder of an internal combustion engine provided with a valve operating mechanism in accordance with the principles of the present invention;

FIGURE 2. has an end elevational view shown in schematic form of a cam shaft drive arrangement for an engine having plural banks of cylinders;

FIGURE 3 is an enlarged detailed vertical sectional view taken substantially along the line IIIIII of FIG- URE l but showing the cam shaft in a different rotational position;

FIGURE 4 is a vertical sectional view, similar to FIG- URE 1 showing a modified embodiment of the invention; and

FIGURE 5 is a vertical sectional view similar to FIG- URES l and 4 showing another modified embodiment of the invention.

As shown on the drawings:

In FIGURE 1 there is illustrated in a fragmentary 3,045,657 Patented July 24, 1962 ice manner a valve and head type of engine to which any one of the several forms of the invention can be adapted. The internal combustion engine illustrated includes a cylinder block 11 and a cylinder head 12. The head 12 is provided with an intake passage 14 from a siutable manifold and an exhaust passage 16 leading to a suitable manifold, wth the manifolds not being shown. The intake of the fuel air mixture into the cylinder 13 is controlled by an intake valve 18 shown to be of the poppet type with a valve stem 19 slidable in a stem guide 17 mounted in the head 14. The valve 18 has a head 21 which coacts with a valve seat 22 to open or close the intake passage 14 as the intake valve 18 is opened and closed.

The exhaust passage 16 is provided with an exhaust valve 24 having a valve stem 26 slidable in a valve guide 23 in the head. The valve 24 has a valve head 27 which coacts with a valve seat 28 formed on the engine head in order to control the flow of exhaust gases from the cylinder 13 as the poppet type valve 24 is opened and closed.

In the arrangement of FIGURE 1 the valves are opened and are also positively closed by

rocker arms

29 and 30 respectively for the intake and

exhaust valve

18 and 24. The rocker arms are actuated by a single cam shaft 31 carrying intake cam means 32 and exhaust cam means 33 and 34, as will be described in further detail in connection with FIGURE 3.

The intake rocker arm 29 is connected at its outer end to the valve 18 by a rotator connector spool 36 which is held to the top of the valve stem 19 by a nut 37. The upper end of the valve stem is tapered at 38 to wedge the spool tightly in place in order that the spool may drive the valve stem in rotation, as will be described. The exhaust valve 24 carries a similar spool 39 at its upper end and the upper end of the valve stem is tapered with the spool being forced down against the taper by a nut 41 threaded onto the stem 26.

The outer end 29a of the rocker arm 29 is bifurcated or forked with one side 42 of the fork being shown. The outer end 30a of the rocker arm 30 is also forked with a side 43 of the fork being shown. The sides of the fork of the rocker arm 29 have arcuate lower surfaces 46 which engage the flange 36b of the spool 36, and the sides of the fork of the rocker arm 30 have lower arcuate surfaces 47 which engage the flange 39b of the spool 39. The arcuate surfaces are identical in the two sides of the forks. The sides of the fork of rocker arm 29 have upper arcuate surfaces 48 which engage flange 36a of spool 36, and the sides of the fork of rocker arm 30 have upper arcuate surfaces 49 which engage fiange 39a of spool 39. The surfaces 48 for the two sides of the fork and the surfaces 49 for the two sides each have .a slight difference in point of contact with their

flanges

36a and 39a. As illustrated by the contact surfaces 49, the side of the fork on the near side in FIGURE 1 engages the flange 39a at 51 and the surface of the fork on the far side of the spool engages the fiange at 54. When the valve 24 is moved by the rocker arm there is a scrubbing action between the spool and the fork end. While the scrubbing action on the two sides of the valve stem is the same while the valve being opened, there is a difference in scrubbing action when the valve is being closed so as to create unidirectional valve rotation. This difference in point of contact is utilized on th upper surfaces of the fork end of each of the

rocker arms

29 and 30. It will be appreciated by those skilled in the art that in some instances it may be desirable to utilize the difference in point contact for the lower surfaces of the forked outer ends of the rocker arms, or on both the upper and lower surfaces.

The inner ends of the rocker arm are operated by the single cam means that is located between them. The rocker arm 30 carries a pin 55, FIGURES 1 and 3, se-

cured thereto by cross pins 55a and 55b. The pin 55 carries a central roller 56 that engages the valve opening cam 32, and with additional rollers 57 and 58 at each side which follow the conjugate shape of the

valve closing cams

34 and 33 respectively. The valve closing cams are constructed so that they may conveniently be broached and include supporting

disk members

59 and 61 mounted on the shaft 31, connected thereto by pins 69 and 71, and also include the cam members 62 and 63 which are provided with circular recesses on the side to fit over the

disks

59 and 61 and be secured thereto by the pins 69 and 71. Thus the inner end of the rocker arm 30 is positively moved in both directions to operate the valve. The other rocker arm 29 also carries a pin 72 with a valve closing roller 73 thereon and with other rollers at the end of the pin operated by the

earns

33 and 34. Thus the same valve opening cam 32 and

valve closing cams

33 and 34 operate both

rocker arms

29 and 30.

Because in one of the piston top dead center positions the inlet valve is already open while the exhaust valve is still open, the cam shaft must rotate in one direction given by the crank shaft rotational direction and the location of the inlet and exhaust valve operating rollers with respect to the cam shaft. Also, because of the angular length of the cam shaft overlap andthe space requirements for the operating rollers or pads, the valves are set at an angle and the rocker arms extend angularly outwardly and downwardly.

With the usual configuration used for V or opposed engines, the two valve operating cam shafts for the two banks of cylinders must rotate in opposed directions. This can be achieved such as by using a roller chain, and as illustrated in FIGURE 2. The engine 74 has a sprocket 76 carried on the crank shaft to drive a roller chain 77. The

cam shafts

78 and 79

carry sprockets

81 and 82 over which the roller chain is threaded so as to drive them in opposite directions as indicated by the arrows. An idler sprocket 83 permits the roller chain to be threaded around the second cam shaft sprocket so as to drive it in an opposing direction from the first cam shaft sprocket.

The rocker arms are each supported on fulcrum members illustrated in the form of compound valve lash

adjusters

84 and 86. The

rocker arms

29, 30 are formed with bearing portions 87, 88 which have inner bearing surfaces 89, 91 and outer bearing surfaces 92, 93a, the bearing surfaces preferably being spherical. The rocker arms pivotally oscillate in the vertical plane defined by the rocker arm and valves, as shown in FIGURE 1. Each of the fulcrum supports 84, 86 for the

rocker arms

29, 30 include an upper fulcrum adjuster and a lower fulcrum adjuster. The upper fulcrum adjuster includes a

piston

93, 94 suitably mounted and secured on a

piston

93, 94 suitably mounted and secured on a piston support 96, 97 which is rigidly mounted on the engine. The piston supports are provided with oil gallerys 98, 99 supplied with pressurized oil from the engine lubrication system. The pistons are provided with

passages

101, 102 to receive oil from the oil gallerys. The pistons are slidably received by

cylinder members

103, 104 which are hollow and which with the pistons define

pressure chambers

106, 107. The cylinder members have spherical lower ends 108, 109 which are seated in the spherical bearing surfaces 89, 91 of the rocker arm. Ball check valves 111, 112 are positioned at the lower end of the

passages

101, 102 and prevent the escape of oil from the

pressure chambers

106, 107 and keep the chambers filled during working. A controlled leakdown from the

pressure chambers

106, 107 occurs through the clearance between the

pistons

93, 94 and

cylinder members

103, 104. The unit leakdown is upward and thus air carried into the

pressure chambers

106, 107 by the oil will easily purge.

The

pistons

93, 94 are mounted in the piston supports 96, 97 and mounting thereby strips 113, 114, are secured to the supports by series of

set screws

116, 117 or other fastening means.

The lower lash adjuster in each instance is larger than the top one so that with equal oil pressure there is a residual force in an upward direction tending to close the valve. The upper adjuster is thus required only to take up the fulcrum reaction when the valve opens. The lower lash adjusters include a

piston

119, 121 with an upwardly facing concave spherical surface 122, 123. The piston is shown as being made of two parts with a hollow interior but this is not material and it can be formed of a single part. The piston is slidable within the cylindrical interior of a cylinder member 126, 127 and pressure chambers 128, 129 are formed within the cylinder member below the piston. The pistons are supported in a support member- 130 mounted on the engine head 12, and having a chamber 131 therein connected to be supplied pressurized oil from the engine lubrication system. Oil flows from this pressure chamber or galley 131 into the pressure chambers 128, 129 of the individual lower fulcrum adjusters forcing the

pistons

119, 121 upwardly to hold valves closed and to take up lash and wear in the valve linkage. Leakdown is in an upward direction to easily purge air.

Springs

132, 133 are mounted in the pressure chamber to urge upwardly on the pistons and hold the linkage snug and to hold the valve closed during periods of nonoperation of the engine and during cranking and starting.

The springs are seated on check valve washers 136, 137. During operation, these washers will be forced upwardly off the bottom of the chambers 128, 129 to permit the flow of oil into the chambers but to prevent back flow. For this purpose, the washers are provided with central orifices 138, 139 which are out of alignment with ports 141, 142 in the base of the cylinder members 126, 127.

In the arrangement of FIGURE 4, the mechanism is simplified and the valves are closed by springs. Parts similar to the embodiment of FIGURE 1 are numbered similarly with a prime mark after the number. Engine block 11 is provided with a cylinder 13' and has an intake passage 14 and an exhaust passage 16. An intake valve 18 and an exhaust valve 24' are mounted in the head 15 of the engine and the valve stems 19' and 26' are slidable in valve guides 17' and 23'. The valves are closed by coil valve springs 143 and 144 seated on the head 15 and held to the valve stems by

spring retaining washers

146 and 147 secured to the stern by collars or

keys

148 and 149.

The valves are operated by

rocker arms

151, 152 which are formed and shaped from sheet steel to a deformed boat shape. The rocker arms have

outer ends

153 and 154 which engage the upper ends of the valve stems 19' and 26 and have inner ends or

pads

156, 157 which engage the valve opening cam 32' mounted on the cam shaft 31'. The valves are again set at an angle with respect to each other and the rocker arms extend angularly downwardly and outwardly and are positioned with respect to the cam 32' to operate in the proper timed relationship. The

rocker arms

151, 152 have inner spherical depressed portions, shown at 158 for the rocker arm 152 which receive the lower spherical end of adjustably supported fulcrum pins 159, 161. The pins are supported in an overhead bnacket 162 and have threaded

portions

163, 164 threaded into the overhead bracket and held in an adjusted position by lock nuts 166, 167. The threaded

portions

163 and 164 are screwed up and down in the bracket to adjust the rocker arm clearance.

Extensions

168, 169 extend downwardly from the overhead support bracket 162 to register with the inner surfaces of the rocker arm and prevent them from rotating out of their Working plane.

FIGURE 5 illustrates another modified form of the invention wherein the valves are moved only to open position by the single cam means and are closed by return springs. The rocker arms. are supported on posts or studs so that no bending is exerted on the stud and the resultant of all forces put on the stud is in tension at all times. Parts which correspond to the arrangement of FIGURE 1 or to the arrangement of FIGURE 4 are numbered similarly with a double prime marking.

An engine block 11" has a cylinder 13" and a head 15" mounted thereon. The head has an intake passage 14" and an exhaust passage 16". The passages are controlled by an intake valve 1 8 and an exhaust valve 24". The stems 19 and 26 of the valves are mounted in valve guides 17", 23". The valves are held closed by valve springs 143, 144" supported on the engine head 15". The valve springs are connected to the upper ends of the valve stems and bear upwardly against valve spring retainer washers 146", 147" held to the valve stems by locks 148", 149".

The valves are opened by

rocker arms

171, 172 and have outer end surfaces 173, 174 to engage the upper end of the valve stems. The rocker arms have inner ends or pads 176, 177 which engage the cam 32 on the cam shaft 31", with the cam pivoting the rocker arms in timed relationship to open and close the intake and exhaust valves '18", and 24. The rocker arms are formed of a depressed section of sheet steel and at a central location have a spherical

depressed bearing portion

178, 179.

Openings

181, 182 are formed through the center of the spherical depressed portion to accommodate a post or stud 183, 184 which is threaded into the engine head 15". A

fulcrum support

186, 187 has a lower spherical surface which seats in the depressed spherical bearing portion 178, 1'79 of the rocker arm and is adjustably held on the post by an

adjustment member

188, 189 threaded to the upper end of the post. The adjustment member is locked in the adjusted position by a locking

nut

191, 192.

In the operation of each of the embodiments the valves are positively opened by a single cam mounted on acentrally located cam shaft. In the arrangement of FIG- URE 1, a cam shaft 31 carries the valve opening cam 32 and the

valve closing cams

33 and 34 which operate the rocker arms 29 and to positively control position of the

valves

18 and 24 and both open and close them. The rocker arms are supported on

fulcrum members

84 and 86 which are compound valve lash adjusters and the lower fulcrum adjuster has a larger piston and cylinder than the upper fulcrum adjuster so as to positively hold the valve closed and both adjusters take up lash and wear in the valve linkage.

Thus will be seen that I have provided an improved valve operating mechanism which meets the objectives and advantages hereinbefore set forth. As compared with a conventional valve gear, the present arrangement eliminates two tappets, two push rods, and one cam, thus substantially reducing the cost of construction of an internal combustion engine. Reduction in parts also increases reliability of operation and reduces the chance for breakdown and requirements for service. The invention is also well suited to use with a simplified expensereducing structure utilizing stamped rocker arms as illustrated in the arrangements of FIGURES 4 and 5.

While each of the illustrations show domed combustion chambers and the shape obtains advantages, the arnangement is not currently in large production because of the cost and complication of the valve gear used. The present arrangement permits the use of a simple valve gear for domed heads by eliminating the disadvantage of the high cost factor. The arrangement however can also be used with a wedge shape or other shape of combustion chamber.

The invention incorporates the use of a single cam to open both the inlet and exhaust valves in the right sequence and at the right time in the cycle, and is Well suited to use with an arrangement, such as shown in FIGURE 1, for positively closed valves by cam operation; or with spring closed valves, as shown in FIGURES 4 and 5 Automatic means to adjust the lash and take up wear may be provided or this may be done by hand adjustment arrangements.

The drawings and specification present a detailed dis closure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and method falling within the scope of the principles taught by the invention.

I claim:

1. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, means for pivotally driving the rocker arm, a fulcrum member on the rocker arm having a downwardly facing convex bearing and an upwardly facing concave bearing, a valve closing unit having a piston member slidably received in a cylinder member, means for mounting one of said members on the engine, an upwardly facing socket on the other of said members receiving said convex bearing, a lash takeup unit having a piston member slidably received in a cylinder member, means for mounting one of said take-up members on the engine, means for the other of said takeup members pivotally received by said concave bearing,

and means for connecting each of said units to the oil pressure system of the engine, so that the fulcrum memer will be held therebetween.

2. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a valve operator to be connected to the valve, a cam follower on said valve operator, a cam shaft to be driven by the engine, having cam means thereon in engagement with the follower to intermittently close the valve during engine operation, and a fluid operated chamber with a movable wall connected to said valve operator and urging the operator in a direction opposite to the direction in which it is moved by said cam means.

3. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a valve operator to be connected to the valve, a cam follower on said valve operator to be driven by a cam shaft driven by the engine to open the valve in timed relationship to engine operation, an oil chamber having a movable wall connected to said valve operator and urging the valve toward closed position, and means for connecting said oil chamber to the engine oil pressure system.

4. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylin der, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, cam follower means at the other end of the rocker arm to be driven by a cam shaft driven by the engine to open the valve in timed relationship to engine operation, a fulcrum member for pivotally supporting the rocket arm, and a fulcrum support for said fulcrum member biasing the fulcrum in a direction to hold the valve closed and taking up lash in the valve assembly.

5. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, cam follower means at the other end of the rocker arm to be driven by a cam driven by the engine, a fulcrum member for pivo-tally supporting the rocker arm, and a lash adjuster for said fulcrum member including a first biasing member urging the fulcrurn member in a direction to close the valve, and a secnd biasing member urging the fulcrum member in the opposite direction, at least one of said biasing members including anexpansible fluid chamber with a member movable in response to fluid pressure therein.

6. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, cam follower means at the other end of the rocker arm to be driven by a cam driven by the engine, a fulcrum member for pivotally supporting the rocker arm, and a lash adjuster for said fulcrum member including a first biasing means urging the fulcrum member in a direction to open the valve having an expansive fluid chamber with a member movable in response to fluid pressure therein, and a second biasing means urging the fulcrum member in the opposite direction and having an expansible fluid chamber with a member movable in response to fluid pressure therein and urging the rocker arm in a direction to close the valve, said second biasing means being stronger than said first.

7. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, cam follower means at the other end of the rocker arm to be driven by a cam shaft driven by the engine to open the valve in timed relationship to engine operation, a fulcrum member for pivotally supporting the rocker arm, a fulcrum support for said fulcrum member biasing the fulcrum member in a direction to hold the valve closed and taking up lash in the valve assembly including an expansible oil chamber with a member movable in response to oil pressure means for connecting the oil chamber to the oil pressure system of the engine, and spring means biasing said fulcrum member in a direction to hold the valve closed operating in the absence of oil pressure in said oil chamber.

8. In a valve assembly for an internal combustion engine having a cylinder with a valve connected to the cylinder, the combination comprising a rocker arm for operating the valve, a connector at one end of the rocker arm for connecting to a valve, cam follower means at the other end of the rocker arm to be driven by a cam shaft driven by the engine to open the valve in timed relationship to engine operation, a fulcrum member for pivotally supporting the rocker arm, a fulcrum support for said fulcrum member biasing the fulcrum member in a direction to hold the valve closed and taking up lash in the valve assembly including an expansible oil chamber with a member movable in response to oil pressure, means for connecting the oil chamber to the oil pressure system of the engine, and means defining a leakdown path for oil extending upwardly from said chamber for the escape of air.

9. In a valve assembly for an internal combustion engine having a cylinder with a reciprocating poppet valve having a valve stem, the combination comprising a pivotally mounted rocker arm for operating the valve in reciprocation by driving the stem, means for pivotally supporting the rocker arm, means for pivoting the rocker arm, first means connected between the valve stem and rocker arm for driving the valve connected at a location laterally offset from the axis of the stem and a first distance from the pivotal axis of the rocker arm, and second means connected between the valve stem and rocker arm for driving the valve connected at a location laterally offset from the axis of the stem and a second distance from the pivotal axis of the rocker arm different than said first distance so that said valve will be rotated by said connecting means.

10. In a valve assembly for an internal combustion engine having a cylinder with a poppet valve the combination comprising a pivotal rocker arm to be connected to the valve for opening and closing the valve, first and second driving surfaces attached to the stem of the valve facing in opposite axial directions and laterally olfset from the axis of the stern, a first driving element on said rocker arm facing said first surface at a location spaced a first distance from the axis of the rocker arm, -a second driving element on said rocker arm facing said first surface at a location spaced a second longer distance from the axis of the rocker arm, and a third driving element on the rocker arm facing said second surface.

11. In a valve assembly for an internal combustion engine having a cylinder with an intake valve for controlling the intake into the engine cylinder, and an exhaust valve for controlling the flow of exhaust gases from the cylinder, an intake rocker arm member to be operatively connected to the intake valve for operating the valve, an exhaust rocker arm member operative to be connected to the exhaust valve for operating the valve, first and second fulcrum means located to support the rocker arm members in a position extending laterally outwardly to connect to the valves at their outer ends, means at the outer ends of said rocker arm members for connecting to the valves, a cam shaft to be driven by the engine, and a single valve closing cam surface and a single valve opening cam surface on the cam shaft in direct engagement with the inner ends of each of said rocker arm members so that the valves are opened and closed in timed sequence by said cam surfaces.

12. In a valve assembly for an engine having an intake valve and an exhaust valve, an integrally formed one-piece shaped intake rocker arm for operating the intake valve having upturned side walls, an integrally formed one-piece shaped exhaust rocker arm for operating the exhaust valve having upturned side walls, each of said rocker arms having a downwardly facing continuous uninterrupted valve operating surface at the outer end to reciprocably actuate a valve with pivotal movement of the arm, having a bearing surface intermediate the ends for pivotally mounting the rocker arm, and having a downwardly extending projection at the inner end formed by an outwardly extending formation of the material of the arm being integral with the arm, first and second fulcrum means for the rocker arms engaging the bearing surface of each arm and pivotally supporting the arms to operate the valves, and a rotating cam having an operating cam surface in direct sliding engagement with the outer surface of the projection at the inner ends of both of the arms for direct transmission of force to said arms.

13. In a valve assembly for an internal combustion engine having a cylinder with an intake valve for controlling the intake into the engine cylinder, and an exhaust valve for controlling the flow of exhaust gases from the cylinder, an intake rocker arm member to be operatively connected to the intake valve for operating the valve, an exhaust rocker arm member operative to be connected to the exhaust valve for operating the valve, first and second fulcrum means for the rocker arm members pivotally. supporting said rocker arm members to extend outwardly to connect to the valves at their outer ends, means at the outer ends of said rocker arm members for operatively connecting to the valves, first and second followers at the inner ends of said rocker arm members, a cam shaft to be driven by the engine extending between said rocker arm members and having a positive action cam thereon with a radially outwardly facing cam surface and a radially inwardly facing cam surface, said inwardly and said outwardly facing surfaces engaged by both of said first and second followers at circumferentially spaced locations so that both followers are operated by the same surfaces of said cam for both positive opening and positive closing of the valves.

14. A valve actuating device comprising a formed onepiece rocker arm to be pivotally mounted for operation, a downwardly facing valve operating surface at one end of the rocker arm on the arm to reciprocably actuate a valve with pivotal movement of the arm, a bearing surface intermediate the ends of the arm for pivotally mounting the rocker arm on a support, an outwardly extending downwardly facing convex projection at the other end of the rocker arm formed by a continuous uninterrupted formation of material on the arm, and a cam surface in direct sliding engagement with the outer surface of said projection on [the rocker arm for direct transmission of force to the arm.

15. A valve actuating device comprising an integrally formed rocker arm to be pivotally mounted for operation, a downwardly facing valve operating surface at one end of the rocker arm to reciprocably actuate a valve with pivotal movement of the arm, a bearing surface intermediate the ends of the arm for pivotally mounting the rocker arm on a support, and an outwardly projected downwardly facing operating surface at the other end of the arm formed by an outwardly extending formation of material having an uninterrupted surface for engagement by said operating surface with an operator to drive the rocker arm in pivotal movement and for direct transmission of force to the arm.

5 References Cited in the file of this patent UNITED STATES PATENTS 1,188,405 Brush June 27, 1916 1,239,933 Miller et al. Sept. 11, 1917 10 1,633,882 Ballot June 28, 1927 1,699,659 Fagan Jan. 22, 1929 1,866,293 Chandler July 5, 1932 2,338,726 Leake Jan. 11, 1944 2,757,653 Links et a1. Aug. 7, 1956 15 2,813,521 Sampietro Nov. 19, 1957 2,871,720 Ralston Feb. 3, 1959 FOREIGN PATENTS 85,857 Austria Oct. 10, 1921 674,180 Great Britain r June 18, 1952