US2142224A - Valve operating mechanism - Google Patents

Description

Jan. 3, 1939. J. D. TURLAY 2,142,224

VALVE OPERATING MECHANISM Filed Dec. 28, 1936 W70 v Y Z22 Patented Jan. 3, 1939 PATENT OFFICE VALVE OPERATING MECHANISM Joseph D. Turlay, Flint, Mich assignor to Gen-' eral Motors Corporation, Detroit, Mich, a corporation of Delaware Application December 28, 1936, Serial No. 117,797

9 Claims.

This invention relates to a valve operating mechanism for an internal combustion engine and more particularly to a valve operating mechanism for a valve of the poppet type in which two or more springs are used for closing the valve.

It is an object of this invention to provide a valve operating mechanism of simple construction that is quiet in operation.

Another object of this invention is to provide a simple means for operating a poppet valve of the type utilizing two or more springs in which noise andwear of parts are greatly reduced over other mechanisms heretofore used.

It is also an object of this invention to provide a means for operating a poppet valve having more than one spring comprising a means which enables the valve springs to be picked up successively.

A further object of this invention is to provide a means for operating a poppet valve having more than one spring, which reduces shock on the mechanism in opening the valve against the valve spring preload over mechanisms heretofore used involving a. plural spring arrangement.

A still further object of this invention comprises a valve operating mechanism in which rocker arm or lifter rattle just after the valve is seated in practically obviated.

Still another object of this invention is to provide a valve operating mechanism for poppet valves having more than one spring, which greatly reduces noise and wear of parts over other devices used in the past without affecting the seating pressure of the valve and without putting a spring load on the cam and lifter mechanism when the valve is closed.

Other advantages and objects of this invention will become more apparent as the description proceeds. Reference is herein made to the drawing forming a portion of this specification in which:

Figure 1 is a view with parts in section of a portion of an internal combustion engine having a poppet valve and two valve springs for seating the valve against its seat, in which the mechanism of this invention is incorporated.

Figure 2 is a view generally similar to Figure l of a modification of the invention.

In Figures 1 and 3 of the drawing, 6 is a poppet valve having a valve stem 8. The valve is shown in seating engagement at [0 with a valve port I2 formed in a head member I3 of an internal combustion engine. A rocker arm 14, pivoted at IE to a valve rocker arm shaft I8, is adapted to be operated by means of any suitable cam and push rod arrangement, not shown in the drawing. The rocker arm at timed intervals will open the valve against the force of inner and outer springs 20 and 22, respectively. The valve stem 8 is slidablyfitted within a bushing 24 mounted within an opening 26 in the head 13.

The upper or free end of the valve stem has two portions 28 and 30 of reduced diameter. c-shaped washers 32 and 34 fitted around the valve stem at the reduced portions 28 and 30, respectively, act as stops or restraining members for a washer 36 and 'a flanged member 38. The flanged member 38 loosely surrounds the valve stem and is held in contact with the C-shaped washer 34 by the inner spring 20. Any move ment applied to the stem while opening the valve I will compress or contract spring 20. The washer 36 loosely surrounds the valve stem and is held in contact with the C-shaped washer 32 while the rocker arm is in its at rest position by means of the outer valve spring,

Resting on the upper surface of the washer 36 is a flanged member 44 having a raised central portion 45 spaced at 48 from the free end of the valve stem when the rocker arm is in inoperative position.

When the rocker arm is actuated by the cam and push rod'the end 48 of the rocker arm will contact the upper surface of the central portion 45 of flanged member 44 and move the same with washer 36 against the ,end of the outer spring 22 and compress the same until the lower surface of the central portion 45 contacts the end of the valve stem.

The end 48 of the rocker arm-will continue to move downwardly and will then move the valve to open the same against the combined pressure of the two springs. In closing the valve against its seat the valve and valve stem will be moved upwardly by means of the energy stored up in the two compressed springs. After the valve is seated the washer 36 and flanged member 44 will be moved upwardly until the washer 36 contacts the C-shaped washer 32. Shock and wear on the mechanism will be reduced without reducing the seating pressure of the valve against its seat by means of the two stage pick up of the springs. A slight clearance 50 is provided between the end 48 of the rocker arm and the upper surface I member 38.

of the flanged member 44 when the rocker arm is at rest. By means of this provision, there will be no spring pressure on the rocker arm and its operating mechanism during inoperative periods of the rocker arm. Noise of the valve mechanism is greatly reduced by the two stage pick up. The outer spring will apply a pressure for a. short period of time on the rocker arm after the valve has closed which will have a steadying effect on the mechanism and eliminate or greatly reduce rocker arm, or lifter, rattle at this time,

In Figure 2, a modification of the invention is disclosed. The device is generally similar to the construction shown in Figure 1, except that the C-shaped washer 34 of Figure 1, is omitted and a flanged member. 52 substituted for the flanged The member 52 has a portion 54 surrounding the valve stem which contacts the under surface of the C-shaped washer 32. The remaining parts of the construction of Figure '2 are identical with those of Figure 1 and are indicated by similar reference numerals.

The operation of the construction of Figure 2 is as follows: The valve rocker arm end 48 will first contact the upper surface of the flanged member 44 and move it with the washer 36, against the pressure of the outer spring 22 until the lower surface of the central portion 45 of the flanged member 44 engages the upper surface of the end of the valve stem, whereupon the C-shaped washer 32 will thereafter cause the member 52 to move downwardly and thus" ation of the rocker arm. Valve lifter rattle is eliminated or reduced as in the device of Figures 1 and 3.

Another embodiment of the invention is shown in Figure 4 of the drawing. The valve springs, the bushing, and head are similar to like parts in Figure 1 and are represented by the same reference characters. A slightly different form of valve stem than that of Figure 1 is shown at 60. The valve stem has a portion 62 of reduced diameter having a threaded end 64. A look washer 66 and nut 68 secures a bushing 10 having a flanged portion 12 to the reduced portion of the valve stem. Above the flanged portion and loosely surrounding the upper portion of the bushing is a washer 14 which is held against the lock washer 66 in the at rest position of the rocker arm by means of the outer valve spring 22. A rocker arm '16 having a forked end .portion 18 is provided for operating the valve. The forked end portion I8 contacts the upper surface of washer 14 on either side of the nut 68 during operation of the valve and is spaced at from the upper surface of the washer during at rest periods of the rocker arm. A small space or clearance 82 is provided between the lower surface of the washer I4 and the upper surface of the flange portion 12 during the at rest period in the cycle of operation. I

In the operation of the device of Figure 4, the rocker arm will be actuated at timed periods and the forked end thereof will be moved to first reduce to zero the clearance 80, whereupon further movement will force the washer 74 downwardly to compress the outer spring 22 until the washer contacts the upper surface of the flange 12. The under surface of the flange contacts the upper end of the inner valve spring 20 and still further movement of the rocker arm will open the valve and thus compress the spring 20 and further compress the outer spring 22. As in the other modifications of the invention, a two stage pick up is provided having the advantages pointed out.

While I have shown and described my invention in connection with a valve operating mechanism of the valve-in-head type, I wish it to be expressly understood that the device is not so limited and the invention may be used with any desired valve operating mechanism utilizing more than one spring.

It will likewise be understood that many changes and modifications may be made in the constructions and arrangements of the several parts without departing from the spirit of my invention and I do not wish to limitthe patent granted thereon other than as necessitated by the prior art.

I claim:

1. In an internal combustion engine, a valve having a stem, two valve springs, means to support one of said springs whereby one end thereof can move with respect to the valve stem a small amount, a fixed stop on said valve stem for limiting movement of the spring end away from the valve seat and means to mount the other spring for movement with the valve stem.

2. In an internal combustion engine, a valve having a stem, an inner and an' outer spring therefor, means to mount the inner spring for movement with the valve stem, means to support the outer of said springs whereby one end thereof can move with respect to the valve stem 2. small amount, a fixed stop for limiting movement of said outer spring end away from the valve seat, and means to compressthe outer spring a small amount and thereafter move the valve stem against the combined pressure of the two springs.

3. In an internal combustion engine, a valve having a stem, a seat for said valve, a plurality of valve springs surrounding said valve stem constantly urging the valve toward its seat, means mounted for movement on said valve stem con tacting one of said valve springs, a stop member for limiting movement of said movable means .in a direction away from said seat, means movable with the valve for contacting another of said valve springs and means for moving said first mentioned means with respect to the valve stem and for thereafter moving the valve against the pressure exerted by the plurality of springs.

4. In an internal combustion engine, a valve having a stem, a seat for said valve, a plurality of valve springs surrounding said valve stem,- a movable washer around said valve stem contacting one of said valve springs, means secured to said valve stem to limit movement of the washer in a direction away from said seat, means movable with the valve contacting another of said valve springs, and means to move the washer and spring contacted thereby with respect to the valve stem and for thereafter opening the valve against the pressure exerted by the plurality of springs.

5. In an internal combustion engine, a valve of springs surrounding said stem, a movable washer around said valve stem contacting one of said springs, means secured to the valve stem to limit movement of the washer in a direction away from said seat, means secured to the valve stem for movement therewith contacting another of said valve springs, and means contacting said washer to move the same and spring contacted thereby with respect to the valve stem and for thereafter opening the valve against the combined spring pressure.

6. In an internal combustion engine, a valve having a stem, a seat for said valve, a plurality of valve springs surrounding said stem, a movable washer around said valve stem engaging one of said springs, means secured to the valve stem to limit movement of said washer in a direction away from said seat, means movable with the valve contacting another of said valve springs, means spaced from the end of the valve stem contacting said washer, means for moving the last mentioned means and washer against the pressure of the first mentioned spring until said means contacts the end of the valve stem and for thereafter moving the valve and stem against the pressure of the plurality of springs.

'7. In an internal combustion engine, a valve having a stem, a flanged member secured to the free end of the valve stem, a valve spring contacting one side of said flange, a washer surrounding the valve stem and a portion of said flanged member, a stop member, a second valve spring contacting one face of said washer and biasing the same away from the opposite face of said flange and into contact with said stop during a portion ofthe cycle of valve operation to provide a clearance between the washer and flange, means for moving the washer into contact with the flange to compress the second mentioned valve spring and for thereafter moving the washer and flanged member to open the valve against the spring pressure exerted by the two springs.

8. In an internal combustion engine, a valve member having a stem, two stop members secured near the free end of said stem, a washer surrounding the valve stem, a flanged member surrounding said valve stem, a spring surrounding said valve stem for biasing said flanged member against one of said step members, a second spring surrounding saidvalve stem for biasing said washer against the other of said stop members during a portion of the cycle of valve operation, and means for moving the washer with respect to the valve stem to compress the second mentioned spring and for thereafter opening the valve against the pressure of the two valve springs.

9. In an internal combustion engine, a valve member having a stem, a stop member secured to the valve stem near the free end thereof, a flanged member surrounding the valve stem, a washer around the valve stem and flanged memher, a first spring for biasing the flanged member against the stop, a second spring surrounding the valve stem for maintaining the washer in con tact with said stop member during a portion of the cycle of valve operation, and means for moving the washer away from said stop and for thereafter moving the flanged member and washer against the combined pressure exerted by the two springs.

JOSEPH D. TURLAY.

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