US2809618A - Valve lift mechanism for internal combustion engines - Google Patents

Description

VALVE LIFT MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Dec. 29. 1954 Oct. 15,1957 R. E. CLUBB ETAL 2 Sheets-Sheet l H Y 5 fiwmv N muw m M w W W 3 n 1957 R. E. CLUBB ETAL VALVE LIFT MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Dec. 29, 1954 2 Sheets-Sheet 2 N, 270L 9 HTTOFh E Y5 Uite VALVE LIFT lv ECHANISM FOR INTERNAL COMBUSTION ENGINES Roy E. Clubb, St. Louis, and Albert W. Weiman, Farmington, M0.

Application December 29, 1954, Serial No. 47 8,416 4 Claims. (Cl. 12390) This invention relates to improvements in valve lift mechanisms for internal combustion engines, and in particular is concerned with a rocker arm type of valve in which the rocker arm is always maintained in contact with the valve stem to prevent chattering, vibration and wear.

In the past, valve lift mechanisms with rocker arm components have been used for valves in internal combustion engines with a positive linkage in which the rocker arm contacted the valve stem only during the operation of the valve. At other times the rocker arm was maintained with a gap between it and the valve stem, and during the operation it would contact the valve stem to efiect the movement of the valve. This has been found to be objectionable as causing chattering and wear on the parts. Also, it has been found that misalignment and out-of-phase operation in such valve mechanisms occur all too often.

By means of this invention there has been provided a valve lift mechanism having a rocker arm component connected by a knee action linkage to a conventional cam shaft or the like to effect the operation of the valve. By means of a biasing element the rocker arm is maintained in contact with the valve stem at all times so there is never any gap therebetween. This prevents chattering and completely eliminates any impact between the rocker arm and the valve stem which would tend to cause wear, attrition, and misalignment.

Accordingly, it is a principal object of this invention to provide a valve lift mechanism having a rotary arm connected to an operating linkage in which there is means to maintain the rocker arm in contact with the valve stem at all times.

It is still a further object of this invention to provide a valve lift mechanism having a rocker arm adapted to contact a valve stem in which there is a rotary linkage means cooperating with a biasing means to maintain the rocker arm in contact with the valve stem during all phases of operation.

Still another object of this invention is to provide a valve lift mechanism having a rocker arm and rotary linkage connection in which there are adjustment means in the linkage to provide for adjustment thereof.

Yet another object of this invention is to provide a valve lift mechanism in which a rocker arm is maintained in contact with the valve stem by a rotary valve lift rod connected by a linkage to the valve rocker arm and a spring biasing means in order that the rocker arm may be made to contact the valve stem.

Still another object of this invention is to provide a valve lift mechanism whereby a rocker arm may be maintained in contact with the valve stem through a rugged construction of single and standard components which are adjustable by unskilled workmen to insure safe and long lasting operation at a minimum of expense.

Further objects of this invention will appear in the detailed description which follows and will further be apparent to those skilled in the art.

atented Oct. 15, 1957 For the purpose of illustration, there is illustrated in the accompanying drawings two embodiments of this invention. It is understood that these illustrations are for the purpose of example only and that the invention is not limited thereto.

In the drawings:

Figure 1 is a view in side elevation of the valve lift mechanism just after the closing operation;

Figure 2 is a top plan view of the valve lift mechanism of Figure 1 with the biasing spring omitted;

Figure 3 is a view in section taken on the line 33 of Figure 1;

Figure 4 is a view in section taken on the line 4--4 of Figure 3';

Figure 5 is a view in side elevation taken similarly to Figure 1, but showing the valve lift mechanism in a different phase of operation just after the valve has opened at the start of the valve opening operation;

Figure 6 is a view similar to Figure 1 taken in side elevation showing the valve in open position just prior to its closing.

Figure 7 is a view in side elevation of a modification of this invention;

Figure 8 is a top plan view of the modified linkage; and

Figure 9 is a cross-sectional view taken on the line 99 of Figure 7.

The valve lift apparatus of this invention is shown in Figure l as including as its main component a valve 10, a rocker arm mechanism 11, and a rotary linkage mechanism 12. This mechanism is adapted to control a valve port 13 in an I. C. engine shown in fragmentary form at 14.

The valve is of conventional construction and includes a valve member 15 having a valve stem 16 with a contact plate 17. This valve is maintained in the normally closed position by a valve spring 18 which bears against the underneath side of the contact plate 17 and the engine 14 at its other end.

The rocker arm mechanism 11 includes a fixed standard 20 at the top end of which a rocker arm member 21 is swiveled about a shaft 22. The rocker arm member 21' has a tappet end 23 which is adapted to bear against the contact plate 17. At the other end of the rocker arm there is a bifurcated portion 26 pivoted to a link 24. A spring support stud is provided at a medial section of the rocker arm member 21 for a purpose to appear.

The valve lift linkage 12 is best shown in Figures 1, 3 and 4. This linkage includes a rotary cam shaft 30 which rotates about a fixed ards. Fixed to this shaft 30 in an eccentric relation is a spool 31. A valve lift disc 34 is fitted about the spool with sliding movement being permitted between this disc and the spool in a rotary manner.

The valve lift disc 34 is fastened to a valve lift rod composed of a bottom section 36 and a top section 37. A turnbuckle 38 connects the threaded adjacent ends of these sections to provide for extensible adjustment thereof.

- The upper rod section 37 is connected to the aforementioned link 24 through a pivot pin 39. The rod section 37 is further provided with an integral stud 40 to provide for the reception of a compression biasing spring .1 between it and the rocker arm stud 25.

In the modification of Figures 7, 8 and 9, the valve mechanism and the valve lift mechanism are identical with that just described and have the same reference numerals. It will, however, be noted that the standard 40 is on the side opposed to the valve lift rod and eccentric. Also, there is a rocker arm 41 which is pivoted at its end 42 on the standard instead of medially as is the case for the embodiment of Figure 1. At the other end the rocker 3 arm is bifurcated to form legs-43 and 44. The bottom medial part of the rocker arm serves as a tappet. A V-shaped link 45 is pivoted at one end at 46 to the top of the valve lift rod 37. At the apex of the link there is another: pivot 47 The .topend of the 'link islconhected vahs depending on the'relative rotational position of the V cam shaft 30. In the conventional internal combustion engine havinga multiple number of cylinders these valves operate sequential operation and there will be valve lift linkage mechanisms such a-s-t-hatshownat 12' for each of'the valves and the eccentrics such as those shown at 31, 32lwill be disposed in selected radialposition about the shaft 30. r p I V The cycle of operation may best be described as beginning-inFigur-e l in which the valve is in a closed position As is evident from an inspection of Figure l, in this particular rotational position of the shaft 30,'wit-h its eccentrics 31 and 32, it is apparent that the link 24 and the upper sect-ion of the valve lift rod 37 could pivot about pin 26 were the biasing spring 41 removed. In

view of this freedom of'movement'the'tappet end 23 of the rocker arm 21 would be out of contact with the contact plate'17' of the valve 10-. To maintainconstant engagernent of the tappet'2'3- withthe contact plate 17', the biasing spring 41 acts to move the pivot pin 3'8-to the right in Figure 1. This, in turn, causes the raising of the pivot pirr26 to elevate it and lower tappet 23 into engagement with the contact plate 17. The spring 41 is a compression spring, and since it is supported by'the stud 25 'adja: cent the fixed shaft 22, this is, in effect, a relatively fixed base so that it constantly urges the topof the pivotal connection of the link 24' and the lift'rod section 37 to the right, as appears in Figure 1. g

This action is maintained until the shaft with its eccentric spool has been rotated in a clockwise manner to the position shown in Figure 5. At this point the'valve lift disc 34 begins to rise clue to the eccentric relationship of the eccentric which is elevated with respect to theshaft 30, as will be seen when compared to the relationship shown in Figure 1. This rising action is substantially vertical with respect to rocker arm 21 so that the greatest force possible is transmitted in the valve opening actionagainst spring 18. As this action occurs, the link 24 also rises and forces the rocker arm member 21 in a counterclockwise movement about its shaft 22 and forces the tappet end 23 down against the contact plate 17 to open the valve 15. This opening action is maintained as the shaft 30 continues to move in a clockwise position until the position shown in Figure 6 has been reached;

Figure 6 represents the positioning of the valve just prior to its closing, and it is fully evident that as the'eccentric spool is rotated by the shaft 30 there will be a rapid lowering of the eccentric. This, in turn, is reflected in the rapid clockwise movement of the rocker arm member 21. This clockwise movement of the rocker arm member is due to. the return biasing action of the valve spring 18 which overrides the weaker compression spring 41 to close the valve. It will be noted that the bifurcated portion of the rocker arm permits a portion of the link 24 and the valve lift. rod to move inwardly of the pivot pin 26 during a portion of the operation so that there is no contact of ports. This eliminates wear.

This completes the. cycle of: operation for the valve lift mechanism of this; invention. Aspreviously mentioned, the biasing spring 41'should be of less force than the valve spring 18 in order that theivalve. can close against the compressive force. ofv said biasing spring; It is apparent attrition or wear caused by impact.

The particular arrangement of the biasing spring 41 is well adapted for use in the valve lift apparatus of this invention since the stud 25 :on the rocker annmember 21 is subjected to very little rotational movement due to its position adjacent to the pivot shaft 22. However, it will be apparent to thoseskilled in the art that biasing spring can be used to maintain contact of the tappet 23 with the contact plate 17 and also to prevent the valve lift rod linkage 12 from riding over center with respect to the pin 26 by alternative arrangements. Thus, the spring 41 could be replaced by a tension spring connected tothe right side of the upper section 37 adjacent'thepin 38 to some fixed point to the right of this linkage assembly; which would maintainthis linkage in the desired position asabove described.

The cycle of operation for the modification of Figures 7, 8t and 9 is the same as that just described for the em bodiment of Figure 1.. However, since the standard 40 is located on the side of the valve opposed tothe lift mechanism, up and down movement of the valve and the lift' valve lift mechanism which maintains: a rocker arm'in constant engagement with the valve stem and which oper- V ates with a minimum of chattering, wear and attrition, and is not subject to getting outof alignment. The adjustment means. of the turnbuckle 33 provides for slight adjustment where desired, and in view of the simple con struction and set up, any repair that may be demanded is made exceedingly simple for relatively unskilled servicemen.

It will be obvious to those skilled in the art that various changes and modifications may be made in the apparatus disclosed in this invention. Such changes and modifications are within the teaching of this invention since it is apparent that. the scope of this invention is not limited to the specfic embodiment shown, which is for the. purpose of illustration only. 7

What is claimed is:

. 1. A valve operating mechanism for operating a valve biased to a. normally closed position, said mechanism including arockerarm having a tappet at a point intermediate its end adapted to move said valve to an open positionin response to movement of an operating means situated at end opposed to another end about which. said arm pivots, saidoperating'means being responsive to a rotary motivating force and including means for maintaining said tappet in. contact with the valve during acomplete cycle ofoperation, said'last named means including i valve to an open position inresponse to movement ofanoperating means connected to the arm'at its other end, said operating means being responsive toa rotary motivating. force and including means for maintaining said tappet in contact with the valve during a complete cycle;

This permits of" of operation, said last named means including a biasing means for urging said tappet against the valve, said biasing means being of a lesser force than said valve biasing means, said operating means including a lift rod adapted to be raised and lowered by said rotary force, and linking means connecting said lift rod to said rocker arm.

3. A valve operating mechanism for operating a valve biased to a normally closed position, said mechanism including a rocker arm pivoted at one end and having contact means in the middle of the arm adapted to move said valve to an open position in response to movement of an operating means connected to the arm at its other end, said operating means being responsive to a rotary motivating force, and including a lift rod adapted to be raised and lowered by said rotary force and linking means connecting said lift rod to said rocker arm, and adjustment means on said lift rod for varying the opening and closing cycle of said valve means for maintaining said contact means in contact With the valve during a complete cycle of operation.

4. A valve operating mechanism for operating a valve biased to a normally closed position, said mechanism including a rocker arm pivoted at one end and having contact means in the middle of the arm adapted to move said valve to an open position in response to movement of an operating means connected to the second end of the arm, said operating means being responsive to a rotary motivating force, and including a lift rod adapted to be raised and lowered by said rotary force and linking means connecting said lift rod to said rocker arm, said linking means comprising a link pivotally connected at an intermediate portion to the second end of the arm with a first end of said link being connected to the left rod and means for maintaining said contact means in contact with the valve during a complete cycle of operation, said last named means including a biasing means urging against a second end of the link in a direction to force said contact means against the valve.

References Cited in the file of this patent UNITED STATES PATENTS 997,138 Keen July 4, 1911 1,182,044 Setz May 9, 1916 1,493,420 Asbury May 6, 1924 FOREIGN PATENTS 7,948 Great Britain Apr. 14, 1905 8,200 Great Britain Apr. 13, 1908 98,498 Germany June 22, 1897 341,484 Germany Oct. 4, 1921

Images