US2446355A - Detent mechanism for pressure regulators - Google Patents

Description

Aug. 3,1948. F. J. WRIGHT DETENT MECHANISM FOR PRESSURE REGULATORS Filed July 20, 1944 when the valve parts are in the positions illus.-.

trated in Fig. 2 of the drawings, the valve is effectively closed and the hydraulic-fluid in chamber 5 is directed through passageway 6 to the supply line 2.

When in response to pressure in chamber I as hereinafter described more completely, the

piston groove or chamber 31 provides a passageway from chamber .5 through more 32 to a cir: cumferential chamber 33 formed in. the main casting 3I which communicates by means of a bore 35 with the drain pipe 4 so that whensaid piston I2 is shiftedas aforesaid, the pressure line I will be connected to the drain pipe 4. Piston I2 is therefore the final control member for the valve 30. I

To provide drainage for any leakage and to preventany development of undesired pressures, particularly on the piston I2, the heads 34 and 36 are provided with drain grooves 40 and M, respectively, which communicate with the drain pipe 4 by way of longitudinal bore 42 in the main casting 3I which communicates with bore 39.

Adjacent its right-hand end, as viewed in Fig. 2 of the drawings, the piston I2 is provided with a pair of spaced peripheral'grooves 20 and-2 5. The groove 25 is actually open at the right-hand end, but it functions the same as though it were closed as is the groove 20.

The main casting 3| is provided with a peripheral groove 43 which receives a plurality of coil springs I'I. These coil springs I1 and associated apparatus co-operate to provide ,an improved type of detent by which the cylinder I2 is releas ably held in either of its two positions, that is, the unloading position or the loading position, and per se and in combination constitutes an important contribution of my invention.

Each of the coil springs I'I, if released, would have a straight linelongitudinal axis down its center. Each spring, however, isbent so that its longitudinal 1 axisis curved as clearly illustrated in Fig. 3 of the drawings. As a consequence, the center inner portion of each coil spring I! rides on the bottom of the groove 20 or 25 of'piston I2, depending on which is opposite the groove 43. The opposite outer free ends of each coil spring I! abut the outer periphery or bottom of the groove 43, and the outer'portion, as viewed in Fig. 3, is received in the groove 43 and contained within the side walls thereof; The groove 43 has sufficient depth so that when adequate pressure is developed on the piston-12 to move it, for example,- to the right from the'position illus-- trated in Fig. 2 of the drawings; each spring I! can #be deflected, bent or flexed so that its longitudinal axis is bent into an arc of smaller radius, and the outer central portion of each said sprifig I'I pressed into said groove 43 while the inner central portion of each rides over the projection between the two adjacent grooves 20 and 25.

Considering this structurein a slightlydiifer cut-manner and referring particularly to Figs.

' 43. As the piston I2 moves and the innerportion 4 V 2 and 3 of the drawings, it is to be noted that the axes of the coil spring I'I lie in a plane which is at right angles to the axis of the piston I 2. When these springs I1 are acting to retain the piston I-2 releasably in either position, the central inner portion of each coil spring is received in a groove or while at leastIa-portion of the entire outer part of each spring, measured radially from the axis of piston t2, extends in the groove 43. However, the outer central part of each spring I I is spaced inwardly from the bottom of the groove 43 or, in other words, from the outer peripheral wall thereof. Furthermore, the axis of each spring I1: is on a curve, the diameter of which is greater than the diameter of the groove r p of each spring I! is deflected radially outwardly, the piston or cylinder I2 is moved to the right,

its axis bends into a circle of smaller diameter and-practically the entire outer peripheral surface of each spring I1 is in contact with the bottom orouter peripheral wall of the groove '43, while each spring I! is relatively free to roll in the groove 43.

. In the operation of the pressure regulator, if the pressure in the accumulator 23 and that in the line 2 are below a predetermined maximum, the valve piston I2 will be in the position illustrated in Fig. 2 of the drawings. Hydraulic fluid undertpressure will be flowing through the pressure line I into the chamber 5 through passageway 6 and past check valve which will be open, to the supply line 2 from which it will flow to the accumulator or directly to the brake piston 22 if the valve 2I is actuated to operate it.

As the pressure builds up, due to the delivery of a reat amount of fluid to the accumulator 2-3, this pressure will be communicated to the piston 8 through the chamber "I and force the piston 8, shoulder pin I0 and spring guide I8 to the right, as viewed in Fig. 2 of the drawings, to cause compression of the pressure adjusting spring I9. .This movement will take place for a time without moving the piston I2 from the position illustrated, and thismovement of the pin III will cause compression of the shifter or snap spring I3 since the washer II will move with the pin I0, and the opposite or right-hand end of the spring I3 is held against the abutting washer III to the piston I2 by means of snap ring I6.

After a. predetermined movement of the pin Ilito the right from that illustrated in Fig. 2 of the drawings, the spacer tube I 4 will abut or strike the washer III, and further movement of said pin III to the right as controlled by piston 8 against the compression of spring I9, will force movement of the piston I2 to theright. During the compression of the snap spring I3 the piston- I2 is held in the position illustrated in Fig. 2 of the drawings, by the detent formed by the coil springs I1, the groove 43 which receives it, and the open end groove 25.

Asthe piston I2 is moved to the right, as above described, the ledge between the grooves 25 and 20 will force thecenters of the coil springs II outwardly into the grOOVe 43 or, in other Words, bend ordeflect them, and once this movement is started, the energy stored up in the snap spring I3 will cause the piston I2 to movewith a snap action to the right, and the center portions of the coil springs I'I will deflect or bend outwardly as said coil springs I'I roll by a distinct rolling action over the peripheral projection of the piston I2 between the grooves 20 and 25,

. It may be noted that this rolling action of the springs I1 provides for a minimum of wear of said springs as well as of the other detent mechanism, including adjacent portions of piston l2. Each spring I! also contributes to a long life and a minimum of wear by virtue of the further fact that it has a large area of contact with the bottoms of the grooves 20 or 25 as well as a large area of contact with the ridge of piston 12 between said grooves as to which it comes into rolling contact as the piston I2 shifts.

The aforesaid snap action to the right will continue until roove 20 of the piston I2 is opposite the groove 43 of the main body 3|, in which position the springs I! will be received in the grooves 20 and the piston I2 will be releasably detained or held in the by-pass or unloading position thereof.

As previously mentioned, when this shifting action has taken place in response to the accumulation of a predetermined amount of fluid in the accumulator 23, or, in other words, a predetermined pressure in supply line 2, the piston 12 provides an unloading of the pumping unit 24 by providing a =by-pass between the pressure line I and the drain pipe 4 by way of chamber 5, bore 32, chamber 31 in piston l2, chamber 38 and bore 39.

As the pressure in the supply line 2 decreases or, in other words, as the volume of stored hydraulic fluid in the accumulator 23 is reduced, pressure on the piston 8 will, of course, be reduced, and the spring 19 will force the piston 8, pin l0 and spring guide 18 to the left, as viewed in Fig. 2 of the drawings, whereupon the snap spring 13 will again be compressed and this action will continue without movement of the piston I2 from its unloading position until the spacer tube l4 strikes the washer III which in response to continued movement to the left will produce thesnap action movement of the piston I2, moving it from its unloading position to its loading position. This movement will cause the detent springs IT to be rolled from the groove 20 to the open end groove 25.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. A detent including a body having a cylindrical bore, a shifta'ble piston in said bore, a groove in said body, a pair of grooves in said piston selectively positionable opposite said body groove as said piston is shifted in said bore, a coil spring in said body groove having two ends contacting the bottom thereof and having a longitudinal axis which is normally substantially straight when said spring is released but which is curved by the action of said piston contacting it, said coil spring having direct contact at its inner center portion with said piston while being held in said body roove, said body groove havin sufficient depth to permit said piston to deflect said spring while moving between its adjacent positions.

2. A detent including a body, a shiftable member in said body, a cylindrical groove in said body, a cylindrical groove in said shiftable member, and a coil spring having two ends and a substantially straight axis when it is released and positioned in said two grooves with its center inner portion contacting the bottom of said cylindrical groove in said shiftable member groove and its ends contacting the bottom of said cylindrical body groove and being thereby bent into an arc of a circle, said coil spring bending into an arc of a circle of smaller diameter and rolling as said control member moves.

' FRED J. WRIGHT.

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

UNITED STATES PATENTS Number Name Date 1,158,955 Apple et a1. Nov. 2, 1915 1,464,303 Whitelaw Aug. 7, 1923 1,475,619 Barney Nov. 27, 1923 1,577,498 Spinney Mar. 23, 1926 1,748,298 May Feb. 25, 1930 1,770,912 Clapp July 22, 1930 1,893,076 Flygare Jan. 3, 1933 1,976,827 Bone Oct. 16, 1934 2,127,293 Gilman Aug. 16, 1938 2,222,346 Eickstaedt Nov. 19, 1940 2,264,375 Hill Dec. 2, 1941 2,276,885 Sherlock Mar. 17, 1942 2,372,016 Rockwell Mar. 20, 1945 FOREIGN PATENTS Number Country Date 426,333 Great Britain Apr. 2, 1935

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