US2183539A - Valve mechanism for motors of pumps - Google Patents

Description

Dec. 19, 1939. F, D, BUTLER 2,183,539

VALVE MECHANISM FOR MOTORS OF PUMPS Filed Jan. 21, 1938 4 Sheets-Sheet 1 I Dec. 19,1939.

F. D. BUTLER VALVE MECHANISM FOR MOTORS 0F PUMPS Filed Jan. 21, 1938 4 Sheets-Sheet 3 Dec. 19, 1939.

F. D. BUTLER 2,183,539

VALVE MECHANISM FOR MOTORS 0F PUMPS.

Filed Jan. 21, 1938 4 Sheets-Sheet 4 I86 I 48b lqc Iq Iq u 1 Ho? m. 1 1 2 I.

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15 M E- Z Patented Dec. 19, 1939 UNITED STATES 'rA'rs N'l OFFICE VALVE MECHANISM FOR -MOTORS OF PUMPS Frank David Butler, United States Navy Application January 21, 1938, Serial No. 186,250

5 Claims. (01.121-157) (Granted under the act 'of March 3', 1883, as

amended April 30, 1928; 3'70 0. G. 757) main valve is controlled by pilot valve, it also relates to valve mechanisms wherein the main valve of the motor is operated direct by some movingelement of such motor. In such motors, I have found that, due principally to poor design, a considerable quantity of the expansive fluid actuating medium is wasted during. each movement of the main valve and each stroke of the main piston member thereof, that the assemblies of the main and pilot valve members of such motors are not very compact incon'struction and that in general these valve mechanisms are expensive to build and are inenicient, unreliable and not very durable in operation.

lhe solution of these major problems, in addi-' tion to the complete accomplishment of their many minor resulting problems, has been long and vainly sought by many in this art. I The major concept of my present invention is the complete solution of these problems andby the provision of simple, durable, efiicient and relativelyinexpensive valve assembly means for its practical and commercial accomplishment.

More specific concepts of my invention con.- template the following:

The provision of an annular shaped main valve member slidably mounted within a cylindrical bore of a suitable valve chest located adjoining the cylinder of the motor, a pair of cylindrically shaped fluid actuating chambers for the purpose of alternately containing the expansive fluid for actuating the main valve member, one chamber'being located adjoining each end of the main valve member and both chambers being considerably smaller in diameter than the outer diameter of. the main. valve member.

The provision of a cylindrically shaped pilot valve member slidably mounted within the main valve member suitable expansive fluid contrc-l'ports located therein for the purpose of controlling the expansive actuating fluid admittance to and exhaust from the. actuating chambers whereby the movement of the pilot valve member may control'the actuation of the main valve member.

The provision of cushioning means for the main valve member whereby either the main or the pilot valve or both may close off the exhaust release from said actuating chambers as the main valve as it nears the ends of its vstrokes.

thuslforming dash-pot compression spaces within the actuating chambers and cushioning the The provision of means for producing greater 'eiiiciency in valve mechanisms of this type by relatively reducing the cubical capacity of the main valve actuating chambers by reducing the diameters of these chambers considerablybelow the diameter of the main valve member, which latter diameter is the usual size of the usual main valve actuating chambers, and also by reducing the cubical capacityof the main cylinder ports by lengthening out the main valve member and locating the enlarged port controlportions of this valve relatively closeto the ends of the motor cylinder, this reducing excess waste of the expansive fluid actuatingmedium;

The provision of compact means for operating the pilot'va'lve member and, v

The provision of means'comprising new and useful entities which practically, commercially, .efiiciently and economically practice to be most advantageous in each of the foregoing, and such other respects which will more clearly appear and be understood by those skilled in this art,

from the accompanying drawings and the following description, and the appended claims:

It will be readily appreciated by those skilled in this art, after understanding my invention, that various changes may be made in theimeans disclosed herein which will produce the same results in substantially the same manner without 'digressing substantially from my inventive concept or sacrificing any of itsoutstanding inherent advantages.

With reference to the drawings: Fig. 1 is a vertical section through the embodiment of my pilot controlled, fluid actuated valve mechanism as applied to the usual type of pump motor cylinder/ Fig. 21s .a vertical section at right angles to the section illustrated in Fig. 1 and shows a preferred but modified embodiment of the valve i'llustratestheusual means for mechanically operating the pilot valve member.

main valve' member nears the end of its enhaust cycle stroke in either direction of travel Fig. 5 is a plan view in section of a portion of Fig. 3 on line 5-5 of Fig. 3.

Fig. 6 is an enlarged detail section of a portion of the valve mechanism assembly illustrated in Fig. 1, and diagrammatically illustrates the movement of the pilot and main valve members from one end of their stroke travel to the opposite end; and

Fig. '7 is an enlarged detailed section of a portion of the modified valve mechanism assembly illustrated in Fig. 3 and diagrammatically illustrates the movement of the pilot and main valve members from one end of their stroke travel to the opposite end.

In the drawings, in which the same reference characters indicate the same parts in the several views, Fig. 4 illustrates the usual typeof vertical, double acting, reciprocating pump assembly having a motor cylinder I opposed by a pump cylinder 2, a piston rod 3 connecting the motor piston 4 and pump piston or plunger 5; a cross head member 6 secured to said piston rod approximately midway between said pistons to actuate the mechanism which operates the pilot valve; a suitably mounted oscillating arm member I adapted to be actuated by the cross-head member; a suitably mounted, hollow, trunnion bearing supported tappet member 8 supported in and actuated by the oscillating arm member I; a tappet rod member 9 to extend through the hollow portion of tappet member 8 and having secured thereto, adjoining either end of the member 8, suitable adjustable tappet nut assemblies Ill and Illa. which are adapted to be intermittently and alternately contacted by the adjoining ends of the tappet member 8 to transmit the reciprocating motion received from said tappet member, via the tappet rod member 9 to the stem end II a of the pilot valve member; and a forked crosshead member I2 secured to the stem end Ila and coupling the tappet rod member 9 and the stem of the pilot valve member together by a suitably mounted wrist pin IZa, thereby allowing rod 9 sufiicient swing for alignment with the stem end I la of the pilot valve member.

With reference to Figs. 2, 3 and 5, the motor power piston 4 is suitably mounted for reciprocation within the motor cylinder I in the usual manner by expansive fluid supplied thereto and exhausted therefrom through a suitable valve chest I3. This chest I 3 has a bore l3a preferably in a plane parallel to closely adjoining the bore Ia of the motor cylinder I. Suitable cylinder and valve chest communication ports I4 and Nb, having the relatively small exhaust cushioning ports Ma and Mo respectively forming a part thereof, extend at right angles to the bores Ia and I3a to connect respectively the upper end of the cylinder bore Ia with the upper end of the valve chest bore Isa and the lower end of the cylinder bore Ia with the lower end of the valve chest bore I3a. A suitable expansive fluid supply connection I5 and exhaust connection lfi are in constant communication with the bore I30. of the valve chest I3.

In the motor drive for the pump assembly as described in the previous paragraph, I provide the combination of main and pilot valve assembly illustrated in Figs. 1 and 6 with the modifications illustrated in Figs. 2, 3, 5 and '7 for the purpose of controlling the expansive fluid supply from the supply connection I5 to the bore Ia of the cylinder I and the expansive fluid exhaust from the bore Ia/of the cylinder I to the exhaust connection I6. In all the assemblies the pilot valve members are located within the main valve members and are operated by an external mechanical or other appropriate means to control intermittently and alternately the expansive fluid supply from the normal source of supply to the expansive fluid actuating chambers, which form the motor cylinders for the actuation of the main valve members, and the expansive fluid exhaust from said expansive fluid actuating chambers to the normal exhaust exit connection.

In each of these valve assemblies the main valve member I! consists of a hollow, elongated spool shaped metal casting which is cored out, constructed and machined so as to reduce its weight to a minimum appropriate to its size, length and required strength. Upper and lower piston head portions Na and Ill) respectively are located on valve member H the same distance apart from one another as the cylinder and valve chest communication ports I4 and MD. Suitable relatively wide snap type upper and lower pressure seal rings I8 and I81) have internal tongue portions which fit in external grooves in the upper and lower head portions Fla and Ill) respectively. Removable upper and lower bushings or liners I9 and I9!) are press fitted to the chamber bore I30. and are secured in position therein by the dowel screws 20. Machined in the circumferences of these bushings are the equally spaced ports I9a and I90 which coincide with and form an extension of the ports I4 and Mb respectively. The ports I90. and I90 are relatively narrower in width than the main valve snap type pressure seal rings I8 and I8?) respectively. These seal rings slidably fit in the inner bores I9d and I9e respectively of liners I9 and I9b to open and close the ports I911. and I90, as will be described more specifically later.

With reference to Figs. 1 and 6, only the rings I8 and I8b contact the walls of the bores IM and I96. The main valve proper is internally supported in the bores of the chest and liner and slidably mounted on upper and lower bores I I0 and Hal cooperating with inward extending projections ZIa and Ma of upper and lower bore covers 2| and 2Ib respectively of the valve chest I3. The length of the projections 2m and Mc between their inner ends and valve stop shoulders 2 Id and 2 Ie is a trifle less than the depth of their respective cylinder chamber bores I10 and lid so that the outer end faces He and [If of the main chamber I! will contact the shoulders 2Id and 2Ie respectively and prevent the inner end faces of the bores I10 and Hal from contacting with the inner end faces of projections 2 Ia and H0.

The stem Ila of the pilot valve member II extends throughout the length of the valve chest I3 and is preferably manufactured of some rust resisting steel alloy. This stern should ordinarily form the pilot valve member proper as i1- lustrated in Figs. 2, 3, 5 and '7, or it may, as in this instance, have pressed thereover and secured thereto an upper cast iron sleeve Ho and a lower cast iron sleeve I Id to form the pilot valve member I I and slidably fit within the inner bore IIg of the main valve member I! and inner bores 2| 1 and 2 I g located at the inner ends of the projections 2Ia and 2Ic. Suitably cylindrically shaped recesses 2Ih and 2Ii are bored in the outer ends of the valve chest bore covers 2| and Zlb to form upper and lower stufiing or packing boxes H71 and 2Ii respectively for the valve stem Ila. These boxes contain the throat bushings 22, packing 22a and glands 22b. The glands 22b are adjustably secured by the stud bolts 22c threaded into the covers 2| and 2 lb.

The pilot valve member II has two diagonal ports extending therethrough. The upper diagonal port IIe originates at its lower end in an annular shaped groove IIg located in the outer circumference of the pilot valve member II. The lower diagonal port Ilf originates at its upper end in a similar annular shaped groove IIh likewise located in the outer circumference of the pilot valve member I I. External to the outer diameter of the pilot valve member II and internal to the bores I10 and H11, of the main valve structure intermediate the inner ends of these bores and the inner ends of the projections 2 la and 2 lo respectively are formed two annular shaped chambers I'Ih and Hi respectively for the operation of the main valve member I'I.

Adjoining the outer ends of the previously mentioned inner bores 2Ig and Zlf of the projections Ho and M0 respectively, and external to the outer diameter of the pilotvalve member II are two annularly shaped exhaust passageway recesses I 612 and I 60 respectively. These recesses I61 and I60 communicate through ports Hid and I6e respectively located in their outer circumferences with the exhaust communication passageway I 6a. Passageway l6a is a cored connection from the bore I3a of the valve chest to the exhaust outlet exit connection I 6 attached thereto. The valve chest bore covers 2| and 2lb are secured to the valve chest I 3 by the stud bolts Zlj and are accurately centered in the bore I311. of the valve chest by the snug fit of the boss projections Zlk thereof in the ends of the bore. The valve chest I3 has two boss projections I 317 integral therewith which coincide with two similar boss projections Ib integral with and located adjoining the ends of the body of the main cylinder I. The valve chest I3 is secured to the cylinder body I and held in contact with the boss projections II) by the stud bolts I30.

The central portion of the valve chest I3 is cored out and forms the expansive fluid supply chest I5a which affords constant communication between the supply connection I5 and the inner portion of the cavity of the bore I3a. Elongated ports I1 and I 1h extend radially through the main valve member I! from the'outer periphery thereof to the inner bore I'Ig thereof intermediate the bores I70 and I'll). Port I1 is the upper expansive fluid supply port for the upper actuating chamber Hit and port IIk is the lower expansive fluid supply port for the lower actuating chamber I12 for operating the main valve member I'I.

In Fig. l the main valve I! and pilot Valve II are illustrated in their normal full downward travel positions under which condition theother moving elements of the pump assembly should normally be in the positions illustrated in Fig. 4 and the motor piston would normally be in the position illustrated in Fig. 3 Under these conditions the expansive fluid entering the supply chest I 5a from the source connection I5 would flow through the radial ports I 90. in liner I911 into the lower communication port I4'b connecting valve chest'bore I3a with cylinder chest bore Ia, thence through the diagonal port I lc'to the space below the main motor piston 4. Simultaneously the space within the cylinder bore I a above the main piston 4 would have free and open access to the exit exhaust connection IS. The expansive fluid would flow and be exhausted from above the piston via the upper communication port I4,-the radial ports Illa into the exhaust communication passageway IBa, and thence into the exit exhaust connection I6.

Simultaneously with the above described expansive fluid supply to and exhaust from the main cylinder, the supply expansive fluid has free access to'flow from the supply chest I5a to the upper actuating motor chamber Hit of the main valve I'I, via the elongated port Iki, into the diagonal port I Ie, or into the annular shaped groove II g and thence into the diagonal port i la, and thence into the chamber Hit and holds the main valve I! in its full downward position of travel with the lower end face I'If in contact with the shoulder ZIe of the projection of the lower cover 2 lb in such a position of travel as to allow full free access passage through ports I91: and I90. As the piston 4 is forced upward the oscillating arm I is oscillated on its, pivot point upward, asdiagrammatically illustrated in Fig. i, and carried with it the tappet member 8 which latter contacts the nut assembly IU of the rod 9 and forces the latter and. consequently the pilot valve member I I upward to a full upward travel position. This will place the diagonal ports He and I I f and the annular shaped grooves I lg and Iih of said member II in the position as diagrammatically illustrated by the dotted lines in Fig. 1 and the full lines in Fig. 6 to cut off the supply of the expansive fluid to the upper actuating chamber I'Ih and connect to the upper exhaust recess I617 via the upper diagonal port I Ie, as illustrated by the dotted lines in the upper portion of Fig. 1.

Simultaneously, as illustrated by the dotted lines in the lower portion of Fig. l and as diagrammatically illustrated in detail in Fig. 6, the lower actuating chamber Hi of the main valve member E1 is connected to the expansive fluid supply. chest I5a and the supply expansive fluid flows from' chest l 5a via the lower elongated port Illa in valve I 1 into the lower annular shaped groove I In and the lower diagonal port Elf, and thence into the lower actuating chamber Hz. This forces the main valve member H, as diagrammatically illustrated in Fig. 6, from its full downward position wherein it contacts the shoulder 21c to its full upward position of travel, only illustrated in part in Fig. 6, in which latter position of travel its upper end face He contacts the shoulder ZId, and a full free access passage through the ports I9a and I is attained. During the upward travel of the main valve H and -a predetermined distance of travel before the passes upward beyond. the upper annular shaped groove II o and the lower end of the upper diagonal port Me of the pilot valve member II and thus cuts off the exhaust release between chamber I III. and the upper exhaust recess passageway I61), forming an efiicient cushioning dashpot of the chamber Ilh which causes a high compression of the expended expensive fluid remaining in said chamber i171. and results in the main valve member I"! coming gently into contact with. the upper shoulder Zld, in place of violently, aswould otherwise be the case. During this same upward travel of the main valve H, the upper snap type ring I8 cuts ofl the exhaust release communication existing between the upper end of the cylinder bore I a and the exhaust exit connection It, as previously described, by travelling upward and covering the ports I 9a,

and opens communication between the expansive fluid supply chest I51; and the communication port It leading to the upper end of the cylinder bore la by uncovering and passing on above said ports IQa to thus admit the supply expansive fluid from chamber ill-a to port It and the space in bore Ia above the main piston 3. Simultaneously during this upward travel of the main valve II, the lower snap type ring I31) cuts off the expansive fluid supply communication existing between the supply chest IEa and the lower end of the cylinder bore Ia, as previously described, by travelling upward and covering the lower ports Iklc and opens communication between the lower end of the cylinder bore Ia and the exhaust exit connection 58 by uncovering and passing on above the lower ports I9c to thus release the expanded expansive fluid from beneath the main piston Q in the cylinder bore Ia via the lower communication ports Mb and lower valve ports I20 into the exhaust passageway connection I804, and thence into the exhaust exit connection I6.

Immediately following the foregoing functions, the main piston 3 starts travelling downward and as it nears the bottom of its downward travel, and the positions as illustrated in Figs. 1 and 4., the tappet member 3 strikes the tappet nut assembly Ilia of the rod 9 and forces the pilot valve member II downward to the position illustrated in Fig. 1, whereby the expansive fluid supply from the chamber I5a to the lower actuating chamber I'Ii, as previously described, is out off and discontinued and in place thereof, with reference to the full lines of the main valve i7 and the dotted diagrammatic lines representing the pilot valve II in Fig. 6, the chamber Hz is connected direct to the lower exhaust recess I50 via the lower diagonal port I If in the pilot valve II, and the expansive fluid in the chamber H1 is expended into the recess I60. Simultaneously the upper actuating chamber I'Ih is connected to the expansive fluid supply chest I511 and the ex pansive fluid flows from supply chest I Eat via the upper elongated port I17 into the annular shaped groove Hg and the diagonal port I lo, and thence into said upper actuating chamber IIh whereupon the main valve I1 is forced downward from its uppermost position of travel, as previously described, towards the position of travel in which it is illustrated in Fig. 1. As the valve I'I nears the latter mentioned position of travel, the lower edge of the bore I'Ig thereof adjoining the lower actuating chamber I'Ii thereof passes downward beyond the lower annular shaped groove I In and the upper end of the lower diagonal. port II I to cut off the exhaust release between said chamber I12 and the lower exhaust recess passageway I60 and, similar to that previously described for the upper travel of valve l1, form an. efficient cushioning dash-pot of the chamber I Ii, which causes a high compression of the remaining expansive fluid in the chamber I Ii and results in the main valve member I! coming gently into contact with the lower shoulder 2Ie in place of violently. as would otherwise be the case, whereupon the complete cycle of operation just described is repeated.

The capacity of the actuating cylinders Hit and and Hi of the main valve member II should only be sufficient to insure the proper operation of the valve member. and the clearance spaces between the inward ends of said cylinders and the ends of the projections 2 Ia. and 2 lo respectively acting as piston plungers therein should be as close as possible to reduce to a minimum, waste of the expansive fluid medium in the type of installation just described, the exhaust expansive fluid only comes in contact with the stuffing box packing 22a and this packing should be maintained suificiently tight on the stem I la of the pilot valve member I! to prevent the latter from moving in an abnormal manner, such as due to the slight drag thereon by the main valve I1.

The valve chest mechanism embodiment just described is identical to that of my preferred embodiment shown in Fig. 2., with the following exceptions: The metal sleeves Ho and [Id of valve member II and the shoulders 2| d and 2Ie of the valve chest bore cover projections 2 la and 2 I0 are eliminated. The inner end faces of the projections 2Ia and 2Ic are machined to a smaller angle than the inner ends of chambers Hit and I1"; and provide the travel contact stops for the main valve member II without forming major seals between the contact joints of said inner ends respectively, and the usual type of mechanical actuating means of the pilot valve member II, as previously described, is substituted by my preferred actuating device for such valve member.

The construction and operation of my pilot valve actuating device for the preferred embodiment of my valve assembly shown in Fig. 2 is as follows: In this device the valve II is operated by the main piston 4 via the upper and lower poppet valve shaped tappet rods 6a and 6b and the upper and lower oscillating levers lo and lb respectively. These rods are slidably mounted in suitable packed guides 23 and 23a which are threaded into the upper and lower cylinder heads 24 and 24a respectively, and form pressure tight access openings through said cylinder heads wherein the rods may operate. The outward side of the enlarged contact discs at the inward ends of the tappet rods 6a and 6b are provided with suitable valve discs 60 and 603 respectively which are adapted to intermittently and alternately contact suitable valve seats 23b and 230 located in the inward ends of the guides 23 and 23a, respectively. This contact depends upon the difference in pressures on either side of the piston d in the cylinder bore Ia, the higher pressure tends to seat the tappet rod adjoining it, thus resulting in the packing of guides 23 and 23a being subjected to reduced pressure only.

The upper and lower oscillating levers "Ia and 'I'b are forked at their inward ends and suspended between pairs of heat treated roller pins 25b in upper and lower crossheads 25 and 25a respectively secured to oppositely threaded opposite ends of the valve member II. Levers Ia and lb are fulcrumed on the pins 'Ie and If respectively of stanchions 7c and Id threaded into the cylinder heads. The levers 1a and 1b are provided with suitable heat treated rollers and roller pins lg and Ih respectively for contact with tappet rods 6a and 8b. The ends of the valve member II are provided with the lock nut 250 for adjusting the stroke of the main piston 4 by reducing the distance between the crossheads25 and 25a and causing the piston 4 to contact the disc ends of the tappet rods Ba and 6b earlier as the piston nears the end of its stroke, thus reversing the pilot valve earlier and resulting in shortening of the stroke of the piston, and vice versa.

In Fig. 2 the moving elements of the pump motor are illustrated in the position they occupy at the completion of the upward stroke of the ward main valve member I! and further results in the expansive fluid being released from below and admitted to above the piston 4 in the bore la of cylinder l. The tappet rod 6a remains in contact with the upper side of the piston until such time as the pressure is higher above than below the piston, whereupon it is forced a slight distance further upward-into contact with its seat 231) as the piston starts receding in the bore la on its downward stroke. 4 nears the end of its downward stroke, it contacts the enlarged disc of the lower-tappet rod 612 and forces the pilot valve ii to reverse, as diagrammatically illustrated by the dotted positions of lever la and lb and the diagonal ports He and H), as shown in Fig. 2.

In the embodiment of my invention-illustrated in Figs. 3, and '7, the cylindrical ends of the main valve IT project into the valve chest bore covers 2i and 21a, instead of the reverse as in the other figures, andsupport the main valve within the valve chest bore. The upper and lower valve actuating chambers Hh and iii are formed intermediate the ends of the main valve I1 and the packing boxes Zlh and 2h, external to pilot valve member H and internal to the covers Zland 2lb respectively. The upper and lower exhaust recesses ltb and I60 and the exhaust ports Mid and Hie thereof are formed in the valve l7 external to valve H, these ports I61: and I60 in this instance in addition to the diagonal ports lie and II of member H out off the exhaust release before the main valve ll reaches the ends of its strokes. The upper and lower diagonal ports He and H7 respectively alternately and intermittently control the expansive fluid supply to and exhaust from the actuating chambers l'lh. and 112 of the main valve H, as in the other embodiments. One dis-. advantage of this embodiment is the fact that the live expansive fluid would be adjacent the inner ends of the packing boxes 2m and Zlz' alternately and intermittently during the operation of reversing the main valve. The lower portion of this embodiment is illustrated in detail in Fig. 7, the full lines showing the uppermost travel of the valves H and I? and the dotted lines illustrating diagrammatically the 'full downward travel of the Valves.

The usual type pilot valve actuating means, as illustrated in Fig. 4, is not adaptable to pumps wherein the motor thereof is short coupled to the pump proper, but the type of valve mechanism as described herein and illustrated in Fig. 2 can be used on either long or short coupled pump assemblies.

With reference to Fig. 2 it is obvious that the pilot valve actuating device therein illustrated could be coupled direct to the main valve l1 and would thus actuate this main valve directly, eliminating the use of the pilot valve. All that would be necessary to be done in such case would be to eliminate the diagonal ports He and Hf in valve ll, secure valve l1 midway in length on and tightly to H, the latter thus forming the stem for I? and also the guide, and eliminate the projections 2 la and 2 lo, or cut them off at the inward ends of the exhaust passageways Nib and I60 respectively. The stroke of the piston 4 could then be adjusted by screwing stem ll into or out of crossheads 25 and 25a.

As the piston Theinvention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. Inan expansive fluid actuated, pilot controlled valve mechanism for a motor cylinder, a valve chest and a valve chest bore, said valve chest adjoining said motor cylinder, an elongated spool shaped expansive fluid actuated main valve controlling the actuating expansive fluid supply to and exhaust from the motor cylinder, a pair of annular shaped chambers, one adjoining each end of said main valve and both being'of appreciably smaller outside diameter than the spool portions thereof providing motor cylinders for actuating said main valve, a cylindrical shaped pilot valve slidably mounted centrally within said main valve, said pilot valve" having a plurality of valve ports extending diagonally therethrough to intermittently and alternately control the expansive fluid supply to and exhaust from each of said main valve actuating motor cylinders, and

cooperative means between said main valve and said valve ports in said pilot valve forming dashpot cushioning chambers of said main valve motor actuating cylinders to cushion said main valve at the ends of its actuated stroke travel.

2. An expansive fluid actuated, pilot controlled valve mechanism for a motor cylinder and a motor piston comprising an elongated spool shaped expansive fluid actuated main valve, a pilot valve, a valve chest, a valve chest bore, said main valve being slidably mounted in said valve chest bore adjoining the motor cylinder, a pair of annular shaped chambers, one adjoining each end of said main valve, said chambers being of appreciably smaller diameter than the enlarged spool portions of said main valve and constituting motor cylinder means for the actuation of said main valve, a cylindrically shaped pilot valve slidably mounted centrally within said main valve, a pair of ports extending diagonally through said pilot valve, one for each of said annular shaped chambers, intermittently and alternately forming communication between a source of expansive fluid supply andits-respective annular shaped chamber and between its respective annular shaped chamber and an exhaust exit, means for externally and intermittently reciprocating said pilot valve whereby such reciprocation of said pilot valve causes said main valve to become expansive fluid actuated to reciprocate intermittently within said valve chest to control the expansive fluid supply to and exhaust from the motor, and means whereby said main valve as it nears the ends of its stroke travel during such actuation cooperates with said diagonal ports in said pilot valve and closes off the exhaust release from said annular shaped chambers to provide dash-pot cushioning means for gently stopping said main valve at the ends of its stroke travel.

3. An expansive fluid actuated, pilot controlled valve mechanism for a motor cylinder comprising a cylindrically shaped expansive fluid actuated main valve, to control the expansive fluid supply to and exhaust from the motor cylinder, a valve chest and valve chest bore adjoining the motor cylinder, said main valve in said valve chest bore, a pair of covers for said valve chest, one closing each end of said chest bore and secured concentrically with said bore, projections extending inwardly from said bore covers providing means slidably supporting said main valve within said valve chest, a cylindrically shaped pilot valve slidably mounted in and concentric with said main valve and said covers, a plurality of annular shaped chambers external to said pilot valve and internal to the fit between the projections of said covers and said main valve adjoining the inner ends of said covers and the outer ends of said main valve forming actuating motor cylinders wherewith to actuate said main valve, and means external to said valve chest for intermittently reciprocating said pilot valve.

4. Claim 3 characterized by port communication extending radially through the midsection of said main valve and connecting a source of expansive fluid supply ,with a portion of the midsection of the fit of said main and pilot valves, a pair of ports extending diagonally through said pilot valve, one for each of said annular shaped chambers intermittently and alternately forming communication means between the source of expansive fluid supply and its respective annular shaped chamber and between the latter and an exhaust exit, and cooperative means between said main valve and said ports.

5. Claim 2 characterized by said means for reciprocating said pilot valve consisting of a pair of elongated cylindrical shaped actuating rods, combined cage and packing stufling box members secured one in each end of the motor cylinder in a plane parallel to the bore of such cylinder, a valve seat portion at the inward end of said box, said actuating rods projecting through said box members into the motor cylinder bore to be intermittently and alternately actuated by the main piston of such motor cylinder, an enlarged disc portion forming a part of each rod at the inward end thereof intermittently seating against the corresponding seat portion of its respective stuffing box member to thus seal such box during such intermittent seating, and a pair of pivoted levers oscillatably mounted one adjoining the outer end of each of said actuating rods, adjustable means on said pilot valve coupling said levers together, whereby said pilot valve may receive an increased parallel motion in relation and proportion to the motion of said actuating rods during the intermittent actuation of the latter by the motor piston.

FRANK DAVID BUTLER.

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