US1488013A

US1488013A - Hydraulic valve

Info

Publication number: US1488013A
Application number: US648155A
Authority: US
Inventors: Emil O Lundblad
Original assignee: Individual
Current assignee: Individual
Priority date: 1923-06-27
Filing date: 1923-06-27
Publication date: 1924-03-25
Anticipated expiration: 1941-03-25

Description

March 25 1924.

E. O. LUNDBLAD HYDRAULI C VALVE 2 Sheets-Sheet 1 Filed June 27 1923 2 Sheets-Sheet 2 HYDRAULIC VALVE E. O. LUNDBLAD Filed June 27 1923 March 25 1924.

Patented Mar. 25, rea -e.

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EMIL 0. LUNDBLAD, F LdEDl OB-D, MASSACHUSETTS.

HYDRAULIC VALVE.

Application filed June 27, 1923.

T0 aZZ whom it may concern:

Be it known that I, EMIL O. LUNDBLAD, a subject of the King of Sweden, residing at Medford, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Hydraulic Valves, of which the following is a specification. Y

This invention relates to a hydraulic valve and has for its object to provide a triple valve of the character mentioned, particularly adapted to control by a single operating member both the admission and discharge of pressure fluid to and from hydraulic presses.

Another object of the invention is to provide a valve capable of first delivering the fluid to a hydraulic press under a c0n1paratively low pressure and then under a relatively higher pressure, it being impossible at any time to apply other than the lowest pressure obtainable first.

Still another object of the invention is to so arrange the inlet valves that they may be opened consecutively to admit the fluid of different pressures, each inlet valve other than the main inlet valve being opened by another inlet valvelocated directly in alignment therewith.

Still another object of the invention is to prevent the waste of pressure fluid by pr0- viding a device having a main inlet valve and an exhaust valve, both of which may be located in their closed positions simultaneously but only one of which may be opened line 2'-2 of Fig. 1.

Fig. 3 is a vertical section taken on the line 3--3 of Fig. 1.

l w'. a is an enlar ed detail horizontal seealve if the Serial No. 648,155.

tion through the main inlet valve, as taken on the line -1al of Fig. 1.

Fig. 5 is a detail transverse section taken on the line 5-5 of Fig. 1.

, l 6 is an enlarged detail plan view of the nut forming a part of the high pressure inlet valve.

Fig. 7 is an enlarged detail plan view of the nut forming a part of the exhaust valve.

Like numerals refer to like parts throughout the several views of the drawings.

In the drawings, 10 represents a casing in the interior of which is a main pressure chamber 11 and an auxiliary pressure chamber 12, said chambers being connected by a main inlet passage 13 in which is a main inlet valve 14. The main inlet valve lat cmbodies therein a primary valve member 15 fast to a valve stem 16 and movable in unison therewith, and a secondary valve member 17 loosely mounted upon and surrounding the said valve stem. The primary valve member 15 is normally seated at 18 upon the secondary valve member 17, while the latter is normally seated at 19 upon a bushing 20 located between the auxiliary pressure chamber 12 and the main pressure chamber 11. The valve stem 16 is provided with a plurality of radially disposed ribs 21, the outer edges of which engage the interior bore of the secondary valve member 17 and said ribs co-operate with said secondar valve member to form ports 22 which extend'longitudinally of the main inlet valve 1-lbetween the valve stem 16 and t. secondary valve member 1'7. The secondary valve member 1'? also tirovided with a plurality of radially disposed ribs 23, the outer edges of which engage the interior bore of the bushing 20 and said ribs co-operate with said bushing to form ports 2% which extend longitudinally of the main inlet valve 14: between the secondary valve member 17 and the bushing 20. The pressure fluid admitted to the auxiliary pressure chamber 12 as will be hereinafter more fully described, acts against the upper extremities of the primary and secondary valve members 15 and 17 respectively and normally holds both seated and therefore closed and normally prevents the entrance of said pressure fluid into the main pressure chamber 11.

Pressure fluid after entering the main pressure chamber 11 passes therefrom li t through an outlet passage and outlet pipe 26, the latter having screw-threaded engagement with the casing 10 and extending trom said casing to a hydraulic press or other device utilizing hydraulic power.

Secured at one end thereof in the casing 10 is a nipple 27 upon the other end of which a casing 28 of a check valve 29.is mounted, and a pipe 30 connects said casing 28 with a suitable source of fluid supply from which pressure fluid under a comparatively low pressure is supplied. A check valve 29 is provided with alow pressure inlet passage 3i in which a valve member 32 is slidably mounted and normally rests upon a seat provided in a bushing 34. The movable valve member 32 embodies therein a valve stem which projects into an opening provided in a screw plug 36 and the latter limits therextent to which the valve member may be raised from its seat The low pressure fluid passes from its source of supply through the inlet pipe $0 check valve 29 and nipple 27 to the auxiliary pressure chamber 12. A casing member 87 is secured to the main casing 10 through the medium of a plurality of bolts 38 and extending through said casing member 37 is a high pressure inlet passage 39 in which a high pressure inlet valve 40 is mounted. The inlet valve 40 embodies therein a prnnary valve member ,41 fast to a valve stem 42 and movable in unison therewith, and a secondary valve member 44 loosely mounted upon and surrounding said valve stem 42. The primary valve member 41 is normally seated at 45 upon the secondary valve member 44 while the latt'r is normally seated at 46 upon a bushing located within the casing member 37. A nut43 1S fast to the lower end portion of the valve stem 42 and'said nut 18 illustrated in detail in Fig. 6, and upon the upper surto torm ports 48 which extend longitudinally of the valve 40 between the va-lve stem 42' and secondary valve member 44. The scondary valve member 44 is alsoprovided with a plurality of radially disposed ribs 49, the outer edges of'which engage the interior-bore of the bushing. in which it is seated, and said ribs co-operate with said bushing to form ports 50 which extend longitudinally of the valve 40 between said secondary valve member 44 and said bushing. The prqssure of fluid above the valve 49 acting against the upper extremities of the primary and secondary valve members 41 and 44 respectively normally holds both seated and therefore closed and prevents the entra-nce ot said pressure fluid into the auxiliary pressure chamber 12.

Fast at one end thereof in the casing member 37 is a nipple 51 on the other end of which a casing 52 of a high pressure check valve 53 is n'iounted and said casing is connected by a high pressure inlet pipe 54 to a suitable source of fluid supply. The casing 52 has an inlet passage provided therein in which a valve member-'56 is slidably:

mounted. and which, when closed, rests upon a seat 57 provided in a bushing 58 mounted in the casing 52. The movable valve member 56 has a valve stem 59 formed integral therewith which projects into an opening ber 56 and passes through the nipple 51 into the chamber above the highpressure 1nlet valve 40 and normally holds said valvein its closed position until it is opened by mechanism hereinafter-to be described.

In order to exhaust fluid from the main pressure chamber 11,7a plugtll has screwthreaded engagement with thecasing 1t) and mounted within an exhaust passage '62 extending through said plug 61 is an exhaust valve 68 which embodies therein a primary valve member 64 having a valve stem 65 formed integral therewith, and a secondary valve member -66 loosely mounted upon .and surrounding said valve stem. :The primary valve member 64 is normally seated at 67 upon the secondary valve member 66, wlnlethe latter 18 normally seated at 68'upon bushing 69 pro-' vided in the plug 61. The valve stem 65 is provided -w1th a pluralityot radially disposed ribsTO, the outer edges of which engage the interiorboreof'the secondary V valve memberr66 and said ribs co-operate with said secondary valve member to form ports 71 which extend longitudinally of the exhaust valve 68 between the valvejstem 65 and the secondary valve member 66;. The se'condary'valve member66 is.also provided with radially disposed ribs 72, the outer edges of which engage the interior bore of the bushing 69 and said ribs co-operate with said bushing to form ports 73 which extend longitudinally of the exhaust valve "63 between the secondary valve member (36 and bushing 69. Z

Fast to the'lower end portionot the valve stem 65 is a nut 74-illustrated in detail in through the pipe 54, lifting the valve mem-= ber 11 and although normally closed by the pressure fluid, said inlet valve is also at times positively closed to prevent leakage therethrough into said main pressure cham her and the exhaust. valve 63 is opened to discharge said pressure fluid from said main pressure chamber by mechanism as follows:

Located within the main pressure chamber 11 is a lever 78, one end of which s forked at 79 and loosely connected to a transvesely extending end portion 80 of the valve The forked portion 79 of the lever stem 16.

*" 1 i v r 72 is constructed and aiianged to engage the/lower extremity of the secondary valve member 17 J11 order that the latter may be liftel from its seat 19 and the portion 80 of the valve stem 16 at times during the operation of the device constitutes a'pivot for the lever 78. The lever '78 has a pair of r downwardly projecting arms 81, the lower extremities of which rest; upon a shouldered portion 82 of the primary valve 'ineinber 64, thereby forming a fulcrum for said lever and the arms 81 have oppositely disposed shoulders 83 which engage the under surface of a head 851 formed at the upper extremity of the primary valve member 6st andprovide a means for lifting the latter.

"lhe'other end portion of the lever 7 8 is also forked at 85 to partially surround a nut- 86 and the fur-cations of saidforked portion engage arms 87 which project from the opposite sides of saidnut.

The nut 86 mounted upon a. screwdilireaded portion 88 of a shaft 89 at the upper end of which is a hand wheel 90. The shaft 89. is mounted to rotatein a bearing-men'iber 91 through which leakage of the pressure fluid is prevented by afstufling b03192. A projection '93 is provided upon the lever 78 and at times said projection is brought into contact witl'i a flat surface 94 provided'within the interiorof the casing 10, and said projection forms a fulcrum for said lever as will. be her inafter more fully explained.

-The general operation of the device is as follows: Assuming that a suitable fluid a't'about 200 pounds pressure entering the auxilianv pressure chamber 12 through the inlet pipe 39 and check valve 29 and that.

similar fluid at approximately 2500 pounds pressure is entering the casing member 37 through the inlet pipe 1 and check valve 53, and also assuming that the main inlet valve ll and exhaust valve 63 are closed as illustrated in Fig. 1, said main inlet valve being held closed by the pressure of the fluid in the auxiliary pressure chamber 12 above said main inlet valve and the exhaust valve 63 being held closed by the lever 78 and nut 86, when it is desired to admit said pressure fluid to the main pressure chamber 11 from which it may pass through the out let pipe Qb' to a hydraulic press or other device actuated by fluid pressure, the operating wheel 90 is turned to rotate the shaft 89 in the proper direction to feed the nut 86 downwardly upon the screw-threaded portion 88 of said shaft. This movement of the nut 86 rocks the lever 78, the arms 81 of said lever constituting. a fulcrum therefor, thereby lifting the primary valve member of the main inlet valve 1 1 and admitting the low pressure fluid through the ports 22 into the main pressure chamber 11. If the nut 86 is only lowered a short distance, the primary valve member 15 alone is opened, but if, however, the hand wheel 90 is still further rotated, the nut 86 is lowered suffioiently to rock the lever 78 so that the upper surface of the forked end 79 thereof will engage the under extremity of the secondary valve member 17 of the main inlet valve 14, thereby lifting said secondary valve member off of its seat 19 and thereafter also admitting pressure fluid to the main pressure chamber 11 through the ports 24; of said secondary valve member. As soon as the pressure fluid enters the main pressure chamber 11, said pressure fluid acts upon the exhaust valve 63 to hold the members thereof tightly closed and said exhaust 'valve will thereafter be held closed as long as thepressure is maintained within said pressure chamber.

The low pressure fluid now having been. turned on to its greatest extent a still further rotation of the hand wheel 90 in the same direction will. cause the lever 7 8 to be still further rocked thereby lifting the primary valve member 15 of the main inlet valve 14: into engagement with the lower extremity of the valve stem 12 of the primary valve memberll of the high pressure inlet valve 10, thereby lifting said valve member and admitting the high pressure fluid through the ports 48 into the auxiliary pressure chamber 12. The high pressure fluid will immediately cause the valve member of the check valve 29 to automatically close but as both members of the main inlet valve 14. are opened, said high pressure fluid will iiun'iediatelv pass to the main pressure chamber 11 and as the exhaust *alve (3:3

. primary and secondary valve members of the mam inlet valv 14 upon their respective isstill held closed, it will pass outwardly through. the outlet pipe :26 to the hydraulic press.

lVhen it is desired to exhaustthe pressure fluid fron'rthe main pressure chamber 11 and its connections'to the hydraulic press,

the hand wheel 90 is rotated in a reverse dierection and the nut-86 is lifted, thereby rock ing the lever 7 8 and utilizing the arms 81 thereof as a fulcrum and again seating the seats. As soon as the main inlet valve 14 is closed, a continued movement of the nut 88 upwardly will first lift the primary valve member (3 1 of the exhaust valve 63,;allowing the pressure fluid within the main pressure chamber to pass outwardly through the ports 71 and still further movement of said hand wheel and nut 86 will cause. the nut 74 at the lower end of the valve stem to engage the under extremity of the secondary valve member .66 and lift the latter from its seat (38 thereby allowing the pressure fluid to also flow outwardly through the ports 73 andsaid fluid will pass off through the exhaust-pipe77. Assoon as the pressure is released froln the. main pressure chamber, the action of the high pressure fluid will close the high pressure inlet valve 40, whereuponthe low pressure fluid will be againadmitted to the auxiliary pressure chamber 12 and said pressure fluid will act to hold the main inlet valve 14 tightly closed.

It is evidentthat at the end of a days work, or at other times, the pressure of fluid above the main inlet valve 14 might be reduced to such an extent that said fluid would not hold said inlet valve tightly closed. in which case the fluid might leak therethrough.

At such times said inlet valve may, be posi- 1 tively held closed by turning the hand wheel 90 in the proper direction to lift the nut 86 to rock the lcver78 so that the projection 3 will contact with the surface 9-1:- at the top of the main pressure chamber 11 and said projection will act as a fulcrum for said lever and will caus the latter to forcethe primary and secondary valve members of the main inlet valve tightly against their respective seats. At this time the primary and secondary valve members of the I exhaust valve 63 will both be open.

It will be noted that during the operation of the device while it is possible for themain .inlet valve 14 and-exhaust valve 63 both to be located in their closed positions simultaneously, that it is impossibleifor both to be opened simultaneously as whenever the main inletvalve is open, the exhaust valve 3 is closed,.,and in likemanner whenever the exhaust valve is opened, the main inlet valve is closed, the result being a great saving of the pressure fluid which usually goes to waste in hydraulic presses.

, consecutively and It will also, be noted that whenever the (PI'GSSLUG fluijd is turned on through the medium .of zthe device, of; the present; invent1on,that the lowest pressure obtainable will 1. 'A device of the character described comprising, in combination,- a casingprovid- Lil ed with amain pressure chamber and a plurality of aligning inlet passages, one of which communicates with 'said .pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage comnuuncatmg therewlth, valves for said inlet passages, a valve for sald exhaust; passage and means to open separately all of said valves.

2. A device of the character described comprising, in combination, a casing provided with a main pressure chamber and a plurality of aligning inlet passages, one of which communicates with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valvesfor said inletpassages,

a. valve for said exhaust passageand-means to open separately all of said valves, each of said valves-being adapted, to be closed by the pressure of fluid thereon.

;3. A device ofthe character described comprising, in combination, a casing provided with;a main: pressurechamber and a plurality of" aligning inlet passages, one of which coimnunicates with ,said pressure chamber, said pressure chamber also having an outlet passage and a'nexhaust passage communicating therewith, valves for .said inlet passages, a valve for said; exhaust passage and means to open said inlet valves also to opei'rsaidexhaust valve. o

"l. device of the character described, comprising, in combination, a casing provided with a main pressure chamber and a plurality of aligninginlet passages, one of which communicates with said-pressure chamber,

- said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valves for said inlet passages, a valveforsaid exhaust passage,1a lever operatively connected to said exhaustvalve and one of said inlet valves and means to operate, said lever and thereby open separately all of said valves.

prising, in combination, a, casing provided with a main pressure. chamber and a plurality of aligning inlet pa ssages, one of which communicates with said pressure chamber, said pressure chamber also havlng'an outlet 5. A devic of the character described comessors passage and an exhaust passage communicating therewith, valves for said inlet passages, a valve for said exhaust passage, a lever operatively connected to said exhaust valve and one of said inlet valves and means to operate said lever and thereby open separately and positively close separately both of said valves to which said lever is con nected.

6. A. device, of the character described comprising, in combination, a casing pro vided with a main pressure chamber and a plurality of aligning inlet passages, one of which communicates with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valves for said inlet passages, a valve for said exhaust passage, a lever pivotally mounted upon said exhaust valve and operatively connected to one of said inlet valves and means to operate said lever and thereby open separately all of said valves.

7. A device of the character described comprising, in combination, a casing pro vided with a main pressure chamber and a plurality of aligning inlet passages, one of which communicates with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valves for said inlet passages, a valve for said exhaust passage, a lever operatively connected to said exhaust valve and one of said inlet valves and means to operate said lever and thereby open separately and positively close separately both'of said valves to which said lever is connected, all of said valves also being adapted to be closed by the pressure of fluid thereon.

S. A device of the character described comprising, in combination, a casing provided with a main pressure chamber anda plurality of aligning inlet passages, one of which. communicates with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valves for said inlet passages, a valve for said exhaust passage, a lever located within said pressure chamber pivotally mounted upon said exhaust valve and operatively connected to one of said inlet valves and means to operate said lever and thereby open separately all of said valves.

9. A device of the character described comprising, in'combination, a casing provided with a main pressure chamber and a plurality of aligning inlet passages, one

of which communicates with said pressure chamber pivotally mounted upon said exhaust valve and operatively connected to one of said inlet valves and means to operate said lever and thereby open separately all of said valves and also positively close separately both of said valvesto which said lever is connected.

10. A device of the character described having, in combination, a casing provided with a main pressure chamber and a plura1- ity of aligning inlet passages for fluids of different degrees of pressure, one of said passages communicating with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage communicating therewith, valves for said inlet passages, a valve for said exhaust passage and means to close said exhaust valve and to open said inlet valves to admit said fluid to said pressure chamber, the pressure of said fluid within said pressure chamber being increased consecutively from the lowest degree upwards.

llnA device of the character described having, in combination, a casing provided with a main pressure chamber and a plurality of aligning inlet passages for fluids ot' diiierent degrees of pressure, one of said passages communicating with said pressure chamber, said pressure chamber also having an outlet passage and an exhaust passage comnumicating therewith, valves for said inlet passages, a valve for said exhaust passage and means to open said inlet valves con secutively to admit said fluid to said pressure chamber, the pressure of said fluid within said pressure chamber being there y increased from the lowest degree upward.

12. A device of the character described comprising, in combination, a casing provided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passage communicating therewith, said casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and having a low pressure inlet passage anda high pressure inlet passage communicating therewith, a valve for said main inlet passage, a valve for said exhaust passage, a valve for said high pressure inlet passage and means to open separately all of said valves.

13. A device of the character described comprising, in combination, a casing pro vided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passage communicating therewith, aid casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage withsaid main pressure chamber and having a low pressure inlet passage and a high pressure inlet passage communicating therewith, a valve for said main inlet passage, a, valve for said exhaust passage, a valve for said high pressure inlet passage and means to open separately all of said valves, each or said valves being adapted to be closed by inlet passage communicating therewith, a valve for said mam inlet passage, avalve for-said exhaust passage, a valve for said high pressure inlet passage, a lever mounted upon said exhaust valve and operativ'ely conn'ected to said maininlet valve and means to rock said lever andthereby open separately all of said valves.

151.1%; device of th character described comprising, in combination, a casing provided with a maiii'pressiii'e chanib'erhaving a main inlet passage, an outlet passage and an exhaust passage communicating there'- with, said casing also being provided with an auxiliary pressure chamber connnun'icating through said main inlet passage with saidmain pressure chamber and having a low"pressure'inlet passage-and a'high pressure inlet passage communicating t-here-' witlnavalve for said'inain inlet passage, a

valve for said exhaust'passage', a valve for said high pressure inlet passage, a lever located within said main pressure chamber and pivotally connected to'said exhaiist valve andalsooperatively connected to saidniain inlet valve and means to rock said lever and thereby open separately all of said valves.

16. A device of thecharacter described coni'prising, in combination, acasing pro vided with a main ressure chamber having a main inlet passage, an out-letpassage and an exhaust passage communicatingtherewith, said casing also being provided withan auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and having a low pressure inlet passage-and a high pres sure inlet passagecommunicating there with, a v'alve for'said main inlet passage, a valve for said exhaust passage, avalve for said-high pressure inletpassage. a lever located within-saidqnain pressure chamber and" pivotally' connected to said exhaust valve and also 'operatively connectedto said main inlet valve and means to rocksaid lever and thereby open separately all of said'valves, anda-lso close both of sa-idvalves" to which said lever is connected 17.- A device of the character described" comprising, in combination, a casing provided with a inaiirpressure chamber having a main iulet'passage, an outlet passage and an exhaushptrssage communicating therewith, said casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and havinga low pressureinlet passage and a high pressure inlet passage communicatingtherewith, a valve for sald main inlet'passage,

a valvet'or said exhaust passage, avalve for said high pressureinlet'passage, a lever-10 cated' withiirsaid main pressure" chamber and pivotallyattached to both said exhaust valve and said main" inlet valve. and means toiock-saidlever. and thereby open separately all of said valves and positivelv' close separately said'main inlet valve" and said exhaust valve. 7

18. A device of the character described comprising, in combinatioma casing provided with am'ain pressure chamber having a-ma'in"inlet'passage', an outlet passage and an exhaust passage communicating i there with, saidcasing also beingiprovided with an auxiliarypressure chamber communicatiiig through said inain inlet passage 'with saidmain' p'ressure' chamber andhaving a low' pressure inlet passage and a high pressure inlet passage communicatingthere with,- a valve for said ma-in inlet passage, a

valve foi"saicl exl1aiist passage, a valve for said h gh pressure inlet passage, a lever located'within saidmain pressure chamber and pivotally attached t-o-"both saidexhaust valve and said main inlet valve and means" torock said lever and -tliereb v opensep'ai rately all of said valves and positively close separately said main' inlet valve and said exhaust valvepall of said valvesalso being adapted to be closed by the "pressure of fluid thereom- 19;A' deviceof the character described comprising,- in combination, a casing pro vided with R'IiIiI'lH'PTQSS-UFG chamber having a" maininlet passage, an'outlet passage and an exhaustpassage communicating therewith, said'casin'galso being provided with an auxiliary pressure chamber coinniunicat ingivthrough said main inlet passage with saidmain pressure chamber and having'an inlet: passage-for a low pressure fluid and an inlet passage for a high pressure fluid" communicating therewith, a valve for said niain inlet pas age; a valvefor said exhaust passage,a valve for said high pressure inlet passage, a*che'ck -valve for' said low pressure fluid, a check valve for said" high pressurefluid; a" lever mounted upon said exhaust-valve and operatively connected to said: main inlet valve andmeans to rocksaid lever and thereby open" sep-'- essors arately said exhaust valve-and said inlet valves and positively close separately said main inlet valve and said exhaust valve.

20. A device of the character described comprising, in combination, a casing provided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passage communicat ing therewith, said casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and having a low pressure inlet passage and ahigh pressure inlet passage communicating therewith, a valve for said main inlet passage, a valve for said exhaustpassage, a va ve for said high pressure inlet passage, a lever located within said main pressure chamber and pivotally attached to both said exhaust valve and said main inlet valve and means to rock said lever and thereby open separately all of said valves and positively close separately said main inlet valve and said exhaust valve, said lever also be ing provided with a projection thereon adapted to constitute a "fulcrum for said lever.

21. A device of the character described comprising, in combination, a casing provided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passage communicating therewith, said casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage with said inain'pressure chamber and having a low pressure inlet passage and a high pres sure inlet passage communicating therewith, a valve for said main inlet passage, a valve for said exhaust passage, a valve for said high pressure inlet passage, a lever located within said main pressure chamber and operatively connected to said exhaust valve and said main inlet valve and means to operate said lever to open and close said exhaust valve and said main inlet valve, said main inlet valve being adapted to engage said high pressure inlet valve and thereby open the latter.

22. A device of the character.described comprising, in combination, a casing provided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passage communicating therewith, said 'asing also being pro vided with an auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and having a low pressure inlet passage and a high pressure inlet passage communicating therewith, a valve for said main inlet passage, a valve for said exhaust passage, a valve for said high pressure inlet passage embodying therein primary and secondary valve members, a lever located within said main pressure chamber and operatively connected to said exhaust valve and said main inlet valve and means to operate said lever to open and close said exhaust valve and said main inlet valve, said main inlet valve being adapted to engage said high pressure lnlet valve and thereby open separately the members of the latter.

28. A device of the character described comprising, in combination, a casing provided with a main pressure chamber having a main inlet passage, an outlet passage and an exhaust passagecommunicating therewith, said casing also being provided with an auxiliary pressure chamber communicating through said main inlet passage with said main pressure chamber and having a low pressure inlet passage and a high pressure inlet passage communicating therewith, a valve for said main inlet passage embodying therein primary and secondary valve members, a valve for said exhaust passage, a valve for said high pressure inlet passage embodying therein primary and secondary valve members, a lever located within said main pressure chamber and operatively connected to said exhaust valve and said main inlet valve and means to operate said lever to open and close said exhaust valve and said main inlet valve, the primary valve member of said main inlet valve being adapted to engage the primary valve member of said high pressure inlet valve and thereby open separately the members of the latter.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

EMIL O. LU NDBLAD.

l'Vitnesses FRANKLIN E. Low, HAZEL F. Barns.