US2439175A - Valve gear - Google Patents

Description

April 6, 1 948. w, LUNDQUlST Q I 2,439,175"

VALVE GEAR Filed Nov. 6, 1943 2 Sheets-Sheet I N V EN TOR. 10

" ATTEIRNEY TON G. umaqwsz'.

April 6, 1948- I w. e. LUNDQUIST 2,439,175

VALVE GEAR Filed Nov. 6, 1943 2 Sheets-Sheet 2 INVENTOR. WILT I G.-LUHDQUIS1Z 'r rpR NEY Patented Apr. 6, 1948 VALVE GEAR Wilton G. Lundquist, Hohokus, N. J assignor to Wright Aeronautical Corporation, a corporation of New York Application November 6, 1943, Serial No. 509,307

.6 Claims. (01. 123-90) This invention relates to improvements in valve gears for internal combustion engines. One of the objects of this invention lies in the provision of a torsion rod-type valve spring in place of the conventional helically wound valve spring. A torsion rod-type valve spring permits the use of higher spring stresses than can be used with a conventional helical spring since better manufacturing control can be exercised in the making of a torsion rod-type spring.

It is a further object of this invention to utilize the same torsion rod-type spring means for a pair of valves and particularly for both the intake and the exhaust valves of a cylinder. The arrangement is such that each valve through its seat provides the spring reaction for the spring force urging the other valve in a, closing direction. It is a further object of this invention to co-axially dispose the valve rocker arms for the intakeand exhaust valves of a cylinder with the torsion rodtype spring means disposed about the common axis of the rocker arms. Specifically, it is an object of this invention to provide a valve gear which comprises a pair of co-ax-ially disposed rocker arms, each having a push-pull connection with its associated valve, and a torsion rod-type spring means common to both the intake and exhaust valves for urging them in a closing direction.

Other objects of this invention will become apparent upon reading the annexed detailed description in connection with the drawing in which:

Fig. 1 is a plane view of a valve gear embodying the invention,

Fig. 2 is an axial section through the valve gear and taken along line i2--2 of Figure 1, and

Figs. 3, 4 and 4A are sectional views taken along lines 33, 44 and 4A4A, respectively, of Fig. 2.

Referring to the drawing, the cylinder head of an internal combustion engine indicated at In is provided with an intake port I2, an exhaust port It, anda valve gear rocker box It. An engine driven cam shaft [8 is journaled within bearings 19 across the top; of the cylinder head within the rocker box'and this cam shaft may serve a plurality of in-line cylinders. The intake and exharust valve stems 2i] and 22, respectively, extend into the rocker box for respective engagement by the rocker arms 2% and 26 which are pivotally mounted about a common axis. A push-pull connection 28 is provided between each rocker arm and its associated valve stem. This connection may be similar to that disclosed in U. S. Patent No. 2,404,827.

The rocker arms 24 and 26 are provided with oppositely extending co-axial journals 3t and 32 spaced by an annular member 33. The rocker box it is provided with suitable split bearing blocks 25 and 21 for the journal 3!) and with split bearing blocks 29 and 31 for the journal 32. The journals 30 and 32 are provided with helically splined sections 34 and 36 respectivelyto which split cam follower supports 38 and 38', respectively, are adjustably clamped by the bolts M. The split construction of the cam follower supports is best seen in Fig. 4. The helical nature of the splines 34 and 36 permits relative rotative adjustment of the cam followers both with respect to each other and with respect to their associated rocker arms. That is, the split construction of the cam follower supports 38 and 38' enables their associated cam followers to be clamped in various relative rotative positions on their helical splines, thereby providing means to adjust the cam to follower clearance. The cam follower supports are each provided with bifurcated extending portions 3'! and 3'! carrying pins 39 about which cam follower rollers at are journaled. Each of the pins 39 is provided with an enlarged head 43 at one end to prevent them from dropping out of their supports, e. g., the pin 39 carried by the bifurcated extension 31 is prevented by the bearing block 29 from working out to the right as viewed in Figure 1 while its head 43 prevents the pin from working out to the left. With the above con-,

struction each of the rocker arms comprises a pair of oppositely extending arms pivotally journaled about an axisat their junction in which the cam follower arm is adjustably clamped about the rocker arm journal relative to the valve engaging arm.

The journals 3!! and 32 are hollow and a plurality of elongated rods 42 are symmetrically disposed therein. These rods are each provided with enlarged non-circular head ends M, of a crosssection permitting them to be compactly nested together. The composite outer surface formed by the head ends 44 of the rods 42 is also non-circular and their right end, as viewed in Figure 2, is adapted to be interfittingly engaged -with-a complementary noncircular interior surface of the journal 30 of the rocker arm 24. The other or left composite head end of the rods 42 is interfittingly similarly engaged by a tubular sleeve i6 which, as hereinafter described, is connected to the one, end of the journal 32 on the rocker arm 25. The nature of the head ends 44 of the rods 42 is best seen in Figure 4A. With this construction a torsional strain may be applied to the 3 rods 42 such that these rods urge both rocker arms in a valve closing direction.

The sleeve 46 is provided with a transversely extending flange 48 having a projection 48' engageable within a slot 49 in pin 50, carried by the bifurcated extension 3'! of the cam follower support 38'. The pin 50 is axially movable relative to the support 38' to permit adjustment of the support along its helical splines 36. The sleeve 46 is also provided with a gear end 52 by which the torsion rods 42 may be initially Wound up to the extent desired in a direction to urge the intake rocker arm 24 in a valve closing direction. The p pin 50 is then axially moved into the path of movement of the projection 48' for reception of the projection 48' in the pin slot 49 to prevent unwinding of the torsion rods 42, whereupon the torsion rods through the projection 48, pin 50, 1 and the cam follower support 38' also urges the exhaust rocker arm 26 in a valve closing direction.

When the cam 54 on the cam shaft l8 engages the cam follower carried by the support 38' to operate the rocker arm 26 and its associated valve, further twisting stress is applied to the left end of. the torsion rods 42 as viewed inFigure 2 by the sleeve 46 through its flange 48, while the intake valve, through its rocker arm '24, provides a reaction againstthe other or right end of the torsion rods. Upon disengagement of the cam 54 and its follower, the torsion rods operate through their. one end, flange 48 of sleeve 46, cam followersupport 38', androcker arm '26 to close the exhaust valve, the intake valve providing the necessary reaction at the other end of the torsion rods. Similarly, when the cam 56 engages its cam follower to operate the rocker arm 24 for opening the intake valve, the rocker arm 24, through its journal 30', applies a further twisting force to the torsion rods against a fixed reaction provided by the exhaust valve through its cam follower support 33' and the projection 48' on the sleeve 46.

The above construction results in a very compact valve gear in which one set of torsion rods 42 provides the valve spring means for urging any two valves in a valve closing direction in which, as illustrated, the valves comprise the intak and the exhaust valves of a given cylinder. This construction eliminates the necessity of providing separate spring means for each valve. Furthermore, the torsion rods are disposed within the hollow rocker arm journals, thereby adding very little to the space occupied by the valve gear.

While I have described my invention in 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 therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

I claim as my invention:

1. In a valve gear for a pair of valves, a first rocker arm operatively connected to one of said valves, a second rocker arm operatively connected to the other of said valves, said rocker arms having hollow .co-axially disposed journal portions for pivotally mounting the rocker arms, and spring means disposed within said hollow journals operatively connected at its one end to one rocker arm and operatively connected at its other end to the other rocker arm for urging both rocker arms in a valve closing direction.

2. In a valve gear for a pair of valves, a first rocker arm operatively connected to one of said valves, a second rocker arm operatively connected to the other of said valves, said rocker arms having hollow coaxially disposed journal portions for pivotally mounting said rocker arms, and a torsionally stressed rod disposed within said hollow journal portions having its one end operatively connected to one of said rocker arms and having its other end operatively connected to the other of said rocker arms for urging both of said rocker arms in a valve closing direction.

3. In a valve gear for a pair of engine valves, a first rocker arm operatively interposed between engine driven means and one of said valves, a second rocker arm operatively interposed between engine driven means and the other of said valves,

, and 'a torsionally stressed straight rod having its bothrocker arms in a valve closing direction.

4. In a valve gear for a pair of valves, a first rocker arm operatively connected to oneof said valves, a second rocker arm'operatively connected to the other of said valves, said rocker arms having hollow co-axially disposed journal portions for pivotally mounting said rocker arms, and a plurality of torsionally stressed rods disposed Within said hollow journal'portions substantially parallel to their axis, said rods having endportions operatively connected to respective rocker arms for urging both said rocker arms ina valve closing direction. v

5. In a gear for operating a valve, a pivotally mounted rocker member operatively connected to said valve, said rocker member having "a pairof opposed arms and an intermediate tubular journal portion, helicalsplines on said 'journal portion to which one of said arms may be secured in various rotative positions, and spring means with' in said tubular journal portion for urging said rocker arm in a valve closing direction.

6. In a gear for operating a valve, a pivotally mounted rocker member operatively connected to said valve, said rocker member having a pair of opposed arms 'and an intermediate journal portion, and helical splines on said journal portion, at least one of said arms having a split bore with internal helical splines co-axial with said bore and adapted to be clamped about said journal portion with said splines in meshing engagement. T

WILTON G. LUNDQUIST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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