US1302556A - Spring for exhaust-valves and the like. - Google Patents

Description

G. T. HUBER.

SPRING FOR EXHAUST VALVES AND THE LIKE.

APPLICATION FILED FEB. I. HHS.

Patented May 6, 1919.

lUNllTFD STATES PATENT GEORGE T. HUBER, OF GLOUCESTER, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO ABBOTT S. COFFIN, OF GLOUCESTER,

MASSACHUSETTS.

SPRING FOR EXHAUST-VALVES AND THE LIKE.

Specification of Letters Patent.

Patented May 6, 1919.

Application filed February 1, 1918. Serial No. 214,995.

To all whom it may concern Be it known that I, GEORGE T. HUBER, citizen of the United States, residing at Gloucester, in the county of Essex and State of Massachusetts, have invented new and useful Improvements in Springs for Exhaust- Valves and the like, of which the following is a specification.

This invention relates to improvements in springs for exhaust valves and the like. It has been developed especially for exhaust valves of internal combustion motors such as are used in aviation, but it has an obvious application to other places. In aeroplane motors, where the quantity of heat and the temperature of the out-flowing gases is such that the region of the stem of the exhaust valve becomes of high temperature it has been found that after a time a spring coiled around the valve stem in the ordinary man ner loses its resiliency and fails to do its work properly in the operation of the valve. Attempts to remedy this have been made by using a spring in which the resiliency is derived from a coil located at one side of the valve stem. But such a spring produces serious wear of the stem bearings, and has other bad results. Notwithstanding its. defects, however, it is the best spring hitherto known so far as I am aware, for places where the special difliculties above stated exist. The object of the present invention is to provide a spring whose resilient parts are safe against injury by the excessive heat of the exhaust, and whose efl'ort as a spring is applied in the direction of and at the axis of the valve stem.

One embodiment of the invention is illustrated in the accompanyingdrawings, but the invention may bepractised in other ways. It is intended that the patent shall coverby suitable expression in the appended claims whatever features of patentable novelty exist in the invention disclosed.

In the accompanying drawings Figure l is a side elevation of a part of an exhaust valve, representing somewhat conventionally the casing of an exhaust valve with its stem and with th spring applied thereto;

2. It is a part of the Fig. 2 is a plan of the spring of Fig. 1 on a larger scale;

Fig. 8 is a side elevation not under tension;

Fig. 4 is a plan of a modified form;

Fig. 5 is a side elevation of the form shown in Fig. 4; and

Fig. 6 is a perspective view of a detail of the form shown in Fig. 4.

Referring to the drawings, 10 indicates a valve stem which passes through a casing 11 having heat radiating ridges 12. The stem has a head 13 consisting of a washer held down by a nut 14 with check nut. The function of the spring is to press upward on the head 13, thus maintaining the valve closed except when the spring is overborne by a superior force such as a cam, not illustrated, which depresses the stem 10 and so opens the exhaust valve. The objects of the invention are accomplished by making the spring of such a construction that its necessary resiliency is obtained from two coils, 15, 15, arranged at a distance from the stem 10 and symmetrically with respect thereto, made of Wire and so formed that the wires, which pass on opposite sides of the stem, cannot spread under the stress of action. Th coils are alike in size and power, and in distance from the valve stem 10. They are fixed on opposite sides of the stem. There are four of said coils, as represented in the drawing, and seen clearly in Figs. 2 and 4, two being at each side; and the wire which constitutes the whole spring is made in two pieces, which as a whole are designated by numerals 21 and 22. pieces have portions of the same spring These two 7 marked respectively b, a, a 6 and Z2 a a 6 They are symmetrical with respect to each other about the axis passing through the valve stein and passing medially between the coils at each end. indicated at m-0c, Fig. invention to provide means by which these two wires are prevented from spreading from each other at the valve stem and are kept so closely together as always to engage that head and to press it along the line of its own axis and with a combined or unified efiect. This is acco'm pli'she'd, in the form illustrated in Figs. 1, 2

and 3, by making a bow or bond 16 in each wire at the place where it is to pass the valve stem, so that it curves around that stem, one wire 21, passing on one side of it and the other wire, 22, pasisng on the other side of it, and then to twist together these wires between this yoke and their respective coils. One effect of such a twist is that it prevents their spreading at the yoke where they together surround the stem of the valve. Another effect is to transfer to the line of the cross axis, and to distribute uniformly over both branches of the yoke at the valve stem, the pressures which are exerted by the respective coils. If the expansive pressure between one pair of arms a, b, Fig. 2, for example, happens to be stronger than that between the arms a 6 nevertheless the-tension of this pair of arms is applied to the arm a before it reaches the valve stem head 13. And in turn any tension emanating from from arms a 6 is transferred to the wire a so that, owing to the twisted portion, these two wires (0 and a press upward on the head 13 with equal force at the yoke 16 assuming of course that this yoke where they pass the stem is set straight. The same is true of the arms a and a The effect on the valve stem therefore is applied as a force acting in a straight line, coinciding with its own axis. As it may be inclosed on all sides by the wires, rather closely, it may be guided with considerable accuracy. In consequence, the valve is drawn straight upon its seat, instead of there being a tendency to cant it as in the best heat-guarded springs heretofore known to me, and without the lateral fric tion of stem guide which results when there is such a sidewise pressure on the stem. The spring thus made consists of two parts, each of which is easily manufactured, and which can be twisted after being put together. The making of the spring with four wire elements projecting from the stem permits the use of relatively small wire. As a result the wire is more easily worked, because heavy wire has heretofore been necesasry; the re siliency can be designed with greater precision according to the actual need, and the spring can be constructed of properly graduated size.

The form illustrated in Figs. 1, 5 and 6 is one in which two portions 21', 22' are fastened together without the twist, there being a metallic clip 20 which has prongs adapted to be bent around the two elements 0, 0 of the wires 21 and 22, which lie parallel with each other so as to prevent their spreading, and which also has a sufficiently broad prong 20' adapted to be bent down into the hole of the yoke 16 to engage the two wires 0 and c therein and so prevent the clip it self from slipping back away from the yoke. Such bending of the clip can be done by machinery, so that however heavy the wire thev two parts of the spring can be easily held rigidly together, without introducing the sharp bend that is involved in the complete twist illustrated in Figs. 1, 2 and 3. In this construction, it is more necessary that the tension of the wires 0 d, and that of the wires 0 and (Z be equal; but this is fairly easy to accomplish because the parts are of such simple and symmetrical shape.

The coils in both cases are shown as equal in size and strength and opposite or balanced in distance and angular location with respect to the stem, because this is the arrangement that I deem best; but it appears that variations from this particular construction might be made without departing from the general idea and principle of the invention. As the stem is inclosed rather closely on all sides by the wires that are bent around it, it is feasible to make the parts that contact with the head 13 of equal elevation, so that the resultant pressure upon it is in direction of the axis, even in cases where an arrangement different from that illustrated is used.

I claim as my invention:

1. A spring for valves and the like, comprising a central portion adapted to engage a valve stem, other portions symmetrical with respect to the valve stem and adapted to engage the casing of said stem, spring portions on opposite sides of the stem at a distance therefrom, and elements extending from the said spring portions to said central and other portions and applying approximately equal pressure to the central portion.

2. A spring for valves and the like, comprising wires formed with a central portion and with spring coils at a distance therefrom; the central portion being shaped to engage a valve stem, and the coils being arranged on different sides thereof, and being of such strength, distance, and direction that in combination they produce a thrust approximately in the direction of the axis of the stem.

3. A spring for valves and the like, comprising two wires, severally having separated spring coils adapted to be on different sides of a valve stem and parts projecting therefrom which at a. distance therefrom are bowed so as jointly to inclose the valve stem closely on all sides.

4. A spring for valves and the like, comprising two wires having portions twisted together and thereby holding each other from spreading, and having portions thus held that are adapted for fitting around a valve stem, and having spring coils on different sides of and at a distance from said stem.

5. A spring for valves and the like, comprising two wires shaped to fit around a valve stem and each having spring coils at a distance therefrom on opposite sides thereof; the coils of each. wire being besidethe corresponding coils of the other Wire; and the portions of each Wire between its coils lying beside and fast to the like portions of the other Wire and including its part of said shape which fits a valve stem.

6. A Composite spring for valves and the like comprising two Wires lying approximately in parallelism with their middle portions engaged together, and adapted to extend past and engage a valve stem; each of said Wires having its end portions on opposite sides of the middle portion, and having spring coils on opposite sides of the middle portions between its said middle and end portions.

Signed by me at Gloucester, Massachusetts, this 22d day of January, 1918.

GEORGE T. HUBER.

Witnesses:

ALBERT BROWN, FRED A. SHACKELFORD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

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