US3033518A

US3033518A - Valve spring retaining means

Info

Publication number: US3033518A
Application number: US735601A
Authority: US
Inventors: Achilles C Sampietro
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1958-05-15
Filing date: 1958-05-15
Publication date: 1962-05-08
Anticipated expiration: 1979-05-08

Description

May 8, 1962 A. C. SAMPIETRO VALVE SPRING RETAINING MEANS Filed May 15, 1958 jiYVEnZUF flab/Wes C. Sam o1 efr'o Unite 3,033,518 VALVE @PRING RETAG MEANS Achilles C. Sampmtro, Detroit, Mich, assignor to Thompson Rama Wooldridge End, a corporation of Ghio Filed May 15, 1958, Ser. No. 735,601 4 Claims. (Cl. 251-4337) The present invention relates broadly to the poppet valve art, and is more particularly concerned with improvements in valve return spring retaining means.

Various forms of valve spring retainers have heretofore been proposed, and while many of these have performed effectively in use, certain important disadvantages have been associated therewith. As for example, known constructions have presented installation problems by reason of the space limitations of the smaller engines. Also, many devices have not been well adapted to mass production techniques. Then too, retainers have been found which'do not maintain the required bottoming position with respect to the spring.

It is therefore an important aim of the present invention to provide a valve spring retainer construction of novel character having the foregoing objections and disadvantages absent therefrom.

Another object of the invention has in the provision of novel spring retainer means for poppet valves functioning in cooperation with the valve return spring to transmit the force therefrom to the valve stem during movement of the valve from an open to a closed position.

Another object of the present invention is to provide a device for cooperatively maintaining a poppet valve in closed position characterized by its formation from a minimum number of readily assembled parts.

I A further object of this invention lies in the provision of a new and improved device comprising a retainer member and locking means therefor arranged in surrounding relation to the valve stem and axially movable therewith by action of the valve return spring to induce complete valve closing by cooperation with spring means positioned between an engine part and said retainer member.

Other objects and advantages of the invention will become more apparent during the course of the following description, particularly when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIGURE 1 is a fragmentary view showing a valve spring retaining means according to the principles of the present invention applied to the poppet valve assembly of an internal combustion engine and with parts broken away and with parts shown in cross-section to illustrate the positioning of the components when the valve is raised during the cyclic operation thereof;

FIGURE 2 is a plan view of the retaining device;

FIGURE 3 is a detail sectional view of the retaining means of this invention as installed on a valve stem; and

FIGURE 4 is a detail sectional view illustrating the positioning of parts during the assembly thereof.

Briefly stated, the novel structure of this invention comprises a disc-like retainer member adapted to be arranged in encircling relation to the valve stem. A central aperture is provided in the retainer member and radially outwardly of the aperture there is formed a plurality of generally conically shaped segments. Positioned between said segments and a shaped groove in the valve stem is a spring which preferably is of generally hair-pin configuration in plan. The described device is acted upon along its lower surface by the conventional valve spring, and the force exerted by said spring is transmitted through the conical segments of the retainer to the hair spring or equivalent means and to the valve stem to maintain Patented May 8, 1962 "ice the poppet valve in a closed position upon completion of the return stroke thereof.

Referring now to the drawings, the valve spring retaining means of this invention, generally indicated by the numeral 10, comprises a retainer member 11 constructed to surround a valve stem 12 having a shaped groove 13 formed therein receiving spring means 14.

The groove 13 in the stem 12 is generally conical and accordingly tapers radially inwardly toward the cap or tip portion 15 of the stem. Between the groove 13 and tip portion 15 is a generally rounded shoulder portion 16 bottoming the spring means 14. Particularly good results have been obtained with groove and shoulder constru-ction shown; however, the conventional straight wall groove may be found in certain applications productive of satisfactory results.

The retainer member 11 is preferably essentially circular in plan, and is provided substantially centrally thereof with an aperture or opening 17 defining a stem receiving bore. At .two diametrally opposed locations thereon the spring retainer 11 is formed to include conically disposed

segments

18 and 19 extending axially and radially outwardly from the base or body portion 20 of the retainer member 11. The segments or

tags

18 and 19 present the form of a pair of partial collars surrounding a portion of the outer diameter of the valve stem 12, and are of arc-like configuration when viewed in plan as in FIGURE 2. The length of the arcs may of course vary, however, preferably said arcs extend between 9'0 and degrees on opposite sides of the valve stem. A punching and coining operation is particularly effective to form the opening 17 in the retainer 11, as well as the tags or

segments

18 and 19 therefrom.

The spring means 14 when viewed in plan is essentially of hair-pin configuration and is shaped to include at one end a substantially circular loop portion 21 connecting with spaced leg portions designated generally at 22 and 23.

Opposite ends

24 and 25 of the

legs

22 and 23 are preferably outturned radially to prevent lateral passage of said ends between the

conical segments

18 and 19. Between said ends and the loop portion 21 of the spring 14 there is provided a pair of spaced

semi-circular portions

26 and 27 bearing along their inner surfaces against the groove 13 and shoulder 16 on the valve stem 12. It is to be noted that the

legs

22 and 23 of the spring 14 are spaced relatively more closely toward one another between the

semi-circular portions

26 and 27 and the loop portion 21, as Well as between the

portions

26 and 27 and the radially outwardly turned

ends

24 and 25 of said

legs

22 and 23. Accordingly, after installation of the spring 14 in the position shown in FIGURES 1, 2 and 3, it is relatively impossible to remove the spring by pulling the same laterally, or that the spring 14 be accidentally displaced from its installed position.

As is. shown in FIGURE/1, the valve spring retaining means 10 of the present invention may be assembled with a poppet valve assembly of the character employed in an internal combustion engine or the like.

In the embodiment shown, an engine part is indicated at 28 which provides a port designated at P having a valve opening 29 presenting a beveled valve seat 39 regulated by the beveled seating surface 31 of a valve head 32 carried on the end of the valve stem 12. The stem is slidably carried in an engine part 33 by means of a valve stem guide 34. A valve spring 35 has one end 36 hottomed against the engine part 33, and an opposite end 37 of the spring 35 bottomed against the base or body portion 20 of the spring retainer member 11.

To assemble the novel device of this invention, the retainer member 11 is moved axially over the tip end 15 of the valve stem 12 into contact with the spring 35 to compress the same in the manner indicated in FIGURE 4.

With the spring 35 in a restrained condition and the

conical segments

18 and 19 of the retainer 11 axially beyond or spaced from the rounded shoulder 16 of the stem 12, the hair-pin spring 14 is expanded by moving the

leg portions

22 and 23 thereof radially outwardly until the spacing between the

semi-circular portions

26 and 27 of the spring 14 is greater than the outer diameter of the vmve stem tip 15. The spring 1 is then released to locate the

semi-circular portions

26 and 27 in the conical groove 13 and bottomed against the rounded shoulder 16. With the springll located upon the valve stem 12 as shown in the drawings the spring retainer member 11 is allowed to move axially toward the tip end 12 of the stem, and upon completion of its axial travel, the retainer 11 makes contact with the outer surfaces of the

semicircular portions

26 and 27 of the spring 14 in the manner of FIGURES 1, 2 and 3. Since the valve spring 35 is preloaded, there is exerted by saidspring a constant force upon the retainer member 11 whereby the inner surfaces of the

conical tags

18 and 19 are continuously in axially bearing relation with respect to the spring 14.

During valve closing movement to the position of FIG- URE l, the valve spring 35 retracts and the force therefrom is transmitted to the body or base 28 of the retainer 11 and the

conical segments

18 and 19 of said retainer against the

semi-circular portions

26 and 27 of the spring 14, thereby exerting an axial force against said

portions

26 and 27 bottomed against the rounded shoulder portion 16 of the valve stem 12. The stem 12 is thereupon maintained in a firmly closed position by transmission of the force against the tip or cap portion thereof. And since the valve spring 35 is constantly preloaded, there is a continuous axial force exerted against the tip 15 of the valve stem 12 to assure that under conditions of vibration the valve head 32 will not be dislodged from its normal seated position.

It may be seen from the foregoing that applicant has provided a valve spring retaining means comprising a minimum number of readily assembled and durable parts.

There is further essentially no likelihood of improper seating contact between the valve head and seating surface by reason of inadequate closure or accidental dislodgement of the head from the seat by vibration or other conditions. The axial force exerted against the valve stem tip 15 maintains a constant pull throughout the entire length of the valve stem 12 and thereby little chance em'sts that the valve will ride open during a full load operation.

'As noted, the groove 13 and rounded shoulder 16 have been found to produce particularly effective results, although the shape of each may be changed as desired without departure from the present invention. Further, while a hair-pin spring is preferred, it is within the contemplation of this invention that other means can be substituted therefor. As for example, when the ratio of the diameter or" the valve stem to the diameter of the groove produced therein is a minor amount over unity, a split ring maybe employed in place of the hair-pin type spring 14.

It will be further appreciated that other modifications may be effectedin the size, shape and: arrangement of parts without departing from the spirit of the invention or the scope of the subjoined claims.

I claim as my invention:

1. In combination with a poppet valve having a grooved stem and a return spring encircling said stern, a retainer comprising asheet form member of uniform thickness having a slotted collar and a base flange extending radi ally outwardly therefrom for bottoming contact with the return spring, said slotted collar defining therethrough an opening for receiving the grooved valve stem; and a hairpin spring having a central looped portion clasping said grooved stem and contacting said slotted collar and further including outwardly turned leg portions of a greater width thansaid slot to prevent accidental dislodgment of the spring, said spring being effective to transmit the return spring force from the retainer to the valve stem.

2. In combination with a poppet valve having a grooved stem and a return spring encircling said stem, a retainer comprising a sheet form member of uniform thickness having a base flange for bottoming contact with the return spring and a pair of radially spaced curved tabs struck axially from the central portion of said member to provide between said tabs in an axial direction a valve stem receiving opening and between said tabs in a radial direction a spring receiving slot; and a hair-pin spring having a central looped. portion clasping said grooved stem and contacting said tabs and further including outwardly turned leg portions of a greater Width than the slot in said collar to prevent accidental dislodgment of the spring, said spring being effective to transmit the return spring force from the retainer to-the valve stem.

3. In combination with a poppet valve having a grooved Stern and a return spring encircling said stem, a retainer shaped to form an outer peripheral flange bottoming on one side thereof the return spring, said retainer having a slotted collar extending axially away from the return spring and radially outwardly with respect to the valve stem to receive said stern therein; and a hair-pin spring having a central looped portion clasping said grooved stern and contacting said slotted collar and further including outwardly turned leg portions of greater width than the slot in said collar to prevent accidental disiodgment of the spring, said spring being effective to transmit the return spring force from the retainer to the valve stem;

4. In combination with a poppet valve having a grooved stern and a return spring encirclingv said stem, a retainer comprising a sheet form member of uniform thickness having a base flange for bottoming contact with the retum spring, and a pair of radially spaced curved tabs struck axially from the central portion of said member to provide between said tabs in an axial direction a valve stem receiving opening and between said tabs in a radial direction a spring receiving slot; and spring means clasping said grooved stern and contacting said slotted collar and further including outwardly turned portions of a greater width than the slot in said collar to prevent accidental dislodgment of the spring, said spring being eifective to transmit the return spring force from the retainer to the valve stem.

References Cited in the file of this patent UNITED STATES PATENTS 846,077 Wishon Mar. 5, 1907 1,775,069 Finney -Sept. 2, 1930 1,840,704 Dawson u Jan. 12, 1932 1,947,534 Payne Feb..20, 1934 1,965,718 Wiley July 10, 1934 2,171,668 Oldham Sept. 5, 1939 2,844,134 Sietman July 22, 1958 FOREIGN PATENTS 1,125,747 France of 1956