US3045658A

US3045658A - Valve operating mechanism

Info

Publication number: US3045658A
Application number: US858176A
Authority: US
Inventors: Achilles C Sampietro
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1959-12-08
Filing date: 1959-12-08
Publication date: 1962-07-24
Anticipated expiration: 1979-07-24
Also published as: DE1576272B1

Description

y 1962 A. c. SAMPIETRO VALVE OPERATING MECHANISM 2 Sheets-Sheet 1 Filed Dec. 8. 1959 2 a L y g a n vfi /////a4v. v /w w a a 6 z j g .5 WW Ma 5 i, m w hjW 5 "IM a JV 9 r 0 C 9 d m 72 1 U 7? m 3 fl i m i H July 24, 1962 A. c. SAMPIETRO 3,045,658

VALVE OPERATING MECHANISM Filed Dec. 8. 1959 2 Sheets-Sheet 2 United States 3,045,658 VALVE OPERATIN G MECHANISM Achilles C. Sampietro, Birmingham, Mich, assignor to Thompson Ramo Wooldridge Inc., Cleveland, Ohio, a corporation of Ohio Filed Dec. 8, 1959, Ser. No. 858,176 3 Claims. (Cl. 12390) The present invention relates to improvements in mechanisms for operating engine valves and particularly to an improved mechanism for an engine having overhead valves employing rocker arms.

The present application is a continuation-impart of my copending application U.S. Serial No. 828,895, filed July 22, 1959.

The invention contemplates the provision of an improved, simplified, inexpensive, stamped or pressed sheet metal one-piece rocker arm with a depressed center and upstanding sides and an intermediate fragmental upwardly facing depressed spherical bearing surface for receiving a fragmental spherical support hearing. The support bearing is mounted on the engine and may be hydraulically controlled in an automatic lash adjusting system or adjustably supported on a fixed support on the engine. The downwardly facing ends of the rocker arm respectively engage a poppet valve stem and a rocker arm operator such as a rotating cam. A guide member is fixedly mounted on the engine such as on the bearing support and is positioned to engage side surfaces of the rocker arm such as by projecting between the sides of the depressed rocker arm to prevent the arm-from swinging laterally out of its plane of movement.

Accordingly an object of the invention is to provide a valve operating linkage of the above type which can be manufactured by simple inexpensive operation without maintaining costly tolerances or employing expensive finishing operation, and wherein few parts are employed and the mechanism is easily assembled with simple adjustments to place it in running condition.

Another object of the invention is to provide an improved valve operating structure employing a pressed sheet metal rocker arm which can be supported on a fragmental spherical bearing and is held in its plane of operation by a simple reliable mechanism.

Another object of the invention is to provide an improved valveoperating linkage employing a rocker arm wherein a guide member is secured to a rocker arm bearing support for maintaining the alignment between the rocker arm and its mating operating parts.

'Otherobjects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which:

FIGURE 1 is a vertical sectional view of a portion of an engine head illustrating a valve operating link-age embodying the principles of the present invention;

FIGURE 2 is a detailed sectional view taken substantially along line IIII of FIGURE 1;

FIGURE 3 is a vertical sectional view taken through an engine head illustrating a modified form of the invention;

FIGURE 4 is a top plan view of the rocker arm and associated mechanism of FIGURE 3; and

FIGURE 5 is a top plan view of the rocker arm with portions removed to show the bearing surface.

As shown on the drawings:

FIGURE 1 illustrates an engine with an engine block 9 having cylinders 10 therein. Mounted on the block is a head 11 with an air intake passage 12 therein leading through an inlet valve port '13 into the combustion chamber which is illustrated as being of the form generally Patented July 24, 1962 known as wedge shaped. The valve port 13 is controlled by an inlet valve 14 with a head 15 seating on a valve seat adjacent the port. The valve has a stem 16 slidably guided by valve guide 17 mounted in the head. At the top end of the valve stem a retainer washer 18 is locked to the valve stem by valve locks 19 seated in a groove 28 in the stem. A coil compression spring 21 is mounted beneath the spring retaining washer 18 and is supported on the head to urge the valve to closed position.

Also provided for the combustion chamber is an exhaust valve, not shown, and the engine block may have additional cylinders and the valves may be arranged in line or the valves may be staggered. In the present preferred illustrated arrangement each of the valves is operated by a pivotal rocker arm which is driven by a cam which directly engages the rocker arm and with an in line valve arrangement separate cams along the cam shaft may operate a rocker arm for each of the valves and the rocker arms are of substantially the same length. If a staggered valve arrangement is employed the rocker arms may be of different lengths, operated by cams on the same cam shaft.

The upper end of the stem of the poppet valve 14 is engaged by a rocker arm 22 which is pivotally supported and directly engaged at its other end by a cam 24 mounted on a rotating cam shaft 23.

The rocker arm 22 is shown in the preferred form as being formed of stamped sheet metal depressed with a downwardly facing end surface 725 for engaging the top end of the valve stem 16 and a downwardly facing surface 26 at the other end for directly engaging the surface of the cam 24.

The center of the rocker arm is depressed to form

upstanding side walls

27 and 28 which have inwardly facing

opposing surfaces

29 and 30.

The rocker arm is pivotally supported for pivotal movement in a substantially vertical plane of operation. The rocker arm is guided in this operating plane and prevented from swinging laterally by a guide member 31 shown in the form of a downwardly projecting lug which is positioned to engage the inner

opposing side surfaces

29 and 30 of the side Walls of the rocker arm in the event the rocker arm tends to swing to either side. This insures that the rocker arm will remain in its operating plane, will be retained in proper engagement with the upper end of the valve stem and with the operating cam, and i side engaging the outside laterally facing surfaces 31a and 32a of the rocker arm. Also, separate guide members could be used positioned on each side of the rocker arm.

The rocker arm is supported by a fragmental spherical bearing and for this purpose at an intermediate portion of the rocker arm is formed a depressed upwardly facing fragmental spherical bearing surface 32. A bearing member 33 has a downwardly facing fragmental spherical bearing surface 34 supportingly seated in the rocker arm bearing surface 32. These bearing surfaces rapidly adjust to each other and can be manufactured without mating tolerances which have to be dependent on each other and a good bearing contact is obtained with a surface which can be readily supplied with oil through a supply means, not shown.

The bearing member 33 has an upwardly extending stud 35 which threads into an overhead bracket 36 with a threaded opening 38. The upper end of the stud 35 is slotted for adjustment of the bearing member 33 and a lock nut 37 turns down on top of the bracket to lock the adjusted position for the proper valve clearance. Since the cam shaft bears directly against the rocker arm, clearances can be maintained at a minimum inasmuch as there are no long linkage lengths to be affected by heat expansion or contraction.

The overhead bracket 36 is suitably supported rigidly on the engine such as by an upright member 39 mounted on the engine head. The guide member 31 which maintains the rocker arm in alignment is preferably supported on the overhead bracket 36 and is shown as being secured thereto to extend downwardly. -As will be seen, assembly of the mechanism can easily be accomplished by merely threading the bearing member 33 into place and sliding the stamped sheet metal rocker into position and adjusting the bearing member. The rocker arm is prevented from swinging out of its plane of operation and therefore will be accurately retained in a location with respect to the cam insuring that the same annular path on the cam will be followed by the surface 26 of the rocker arm. This will also permit the use of a cam with a varying contour along its axial length.

In the arrangement of FIGURE 3, a similar arrangement is employed with the rocker arm supported on a post or stud which is secured to the engine head and a guide member of different structure is employed.

In FIGURE 3, an engine block 49 has a cylinder and combustion chamber 50, and a head 51 with an air inlet passage is mounted on the block. The air flows into the combustion chamber through a valve port 53 which is controlled by a poppet valve 54 having a head 55 and a stem 56 slidably guided by a valve guide 57 mounted in the head. At the upper end of the valve stem a spring retaining washer 68 is locked to the stern by locks 69 mounted in a groove 70 and a coil compression spring 71 is held beneath the washer 68 and is supported on the head to hold the valve 54 in closed position.

The valve is operated by a pivotally supported rocker arm 72 driven by a cam 74 mounted on a cam shaft 73 extending along the engine.

The rocker arm again is preferably of stamped sheet metal depressed to form a surface 75 at one end for engaging the upper end of the valve stem, and a surface 76 at the other end for directly engaging the cam 74.

The rocker arm is pivotally supported on the engine on a stud or post 77 which is illustrated as being threaded into a threaded opening 78 in the head. A lateral pin 78a locks the post 77 against rotation. If desired, the post may be shrunk into the head in indexed position.

The post has an upper reduced portion 77a which extends through an opening 79 in a fragmentary spherical depressed bearing portion 80in the rocker arm. The bearing portion 80 receives a supporting bearing 81 with a downwardly facing fragmentary spherical bearing surface 82.

The bearing 81 has a center opening and is slid over the top of the post and adjustably held thereon by a threaded nut 83 and a lock nut 84.

As illustrated in FIGURES 3 and 4, the sheet rocker arm has upstanding sides 85 and' 86 and is prevented from swinging laterally on the bearing 81, out of its operating plane, by a guide member 87. The guide member engages the inner facing opposing

side surfaces

88 and 89 of the side walls of the rocker arm. The guide member is fixedly mounted with respect to the engine and is preferably supported on the post 77 by being slid over the top of the post and located beneath the nut 83. To lock the guide member against rotation, the post has a flattened milled area 90 and a surface 91 in the inner opening of the guide member seats against the surface 90 to prevent rotation with respect to the post. Similar rotation preventing means may be employed such as by using a keyway and key.

As will be understood, although the examples illustrated have a manual adjustment for valve clearance, the principles of the invention may be employed with auto- A. motive fulcrum lash adjusters wherein the supporting bearings for the rocker arm are hydraulically positioned.

Thus it will be seen that I have provided an improved valve operating linkage employing a stamped rocker arm which is lightweight for reduced inertia effects and is shaped for strength of operation and prevention of deformity during forming and use. The rocker ,arm bears directly on the cam shaft for the reduction of the number of parts required to reduce cost of manufacture and installation and reduced effects of expansion and contraction, to thereby improve operation of the engine.

The drawings and specification present a detailed disclosure 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 methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. A valve operating mechanism for an engine comprising a formed rocker arm having a fragmental spherical bearing portion intermediate the ends for pivotally supporting the arm and having upturned side portions with vertical planar inner side sliding surfaces parallel to the plane of pivotal movement of the rocker arm, a fixed support for the rocker arm, a bearing member on the support having a fragmental spherical bearing surface in supporting engagement with said bearing portion of the arm and having an axis in said plane of pivotal movement of the rocker arm, and a guide member non-rotatably mounted on said support in a fixed predetermined angular position relative to the support and to said axis and having side surfaces with at least one of said side surfaces being in continual sliding engagement with one of said planar side surfaces of the arm during normal operation.

2. A valve operating mechanism for an engine comprising a formed rocker arm having a fragmental spherical bearing portion intermediate the ends for pivotally supporting the arm and having upturned side portions with vertical planar inner side slidin surfaces parallel to the plane of pivotal movement of the rocker arm, a fixed support for the rocker arm, a bearing member on the support having a fragmental spherical bearing surface in supporting engagement with said bearing portion of the arm and having an axis in said plane of pivotal movement of the rocker arm, an adjustable element connecting the bearing member to the support and adjustably supporting the bearing member to adjust and fix the clearance between the rocker arm and a valve operated by the arm, and a guide member rigidly fixed in non-rotatable position on said support projecting downwardly from the support in a fixed predetermined angular position relative to the support and with respect to said axis and having side surfaces with at least one of said side surfaces being in continual sliding engagement with one of said planar side surfaces of the arm during normal operation.

3. A valve operating mechanism for an engine comprising a formed rocker arm having a fragmental spherical bearing portion intermediate the ends for pivotally supporting the arm and having upturned side portions with vertical planar inner side sliding surfaces parallel to the plane of pivotal movement of the rocker arm, a fixed support for the rocker arm including a threaded stud extending upwardly from the engine head through an opening in said spherical bearing portion, a bearing member on the support having a fragmental spherical bearing surface in supporting engagement with said bearing portion of the arm, said bearing member slidably mounted on the vertical stud, a nut member threaded on the stud for adjusting the vertical position of the bearing member, and a guide member non-rotatably mounted on said stud in a fixed predetermined angular position relative to the axis of the stud and having side surfaces with at least spemss one of said side surfaces being in continual sliding engagement with one of said planar side surfaces of the arm during normal Operation.

References Cited in the file of this patent UNITED STATES PATENTS 6 Poppe Feb. 17, 1925 Fagan Jan. 22, 1929 Read Sept. 13, 1932 Halford Apr. 7, 1936 Kutz Sept. 5, 1950 Leach Sept. 1, 1959 Fedak Oct. 11, 1960 Streit et 'al Jan. 16, 1962