Oct'29, '1946. L.-, E. LA BRIE FLUID _rREssURE PRÓDUGING DEVICE ' 4Filgd July 21, 194s l \ \\N` am “ NN Y 2,410,16‘9 2,410,169 Patented oa. 29, 1946 UNITED STATES PATENT ori-‘ICE 2,410,169 FLUID 'PRESSURE PRODUGING DEVICE - Ludger E. La Brie, Detroit, Mich., assignor to Hydraulic Brake Company, Detroit, Mich., a ` corporation of California Application July 21, 1943,-SerialNo. 495,638 6 Claims. (Cl. G0L-54.6) 2 1 This invention relates to fluid pressure braking systems, and more particularly to ñuid pressure producing devices therefor. vT'he invention comprehends a fluid pressure producing device including a low pressure pro ducing means, an intermediate pressure produc ing means and a high pressure producing means, and means operative upon attainment of a pre determined‘pressure in the low and interme diate pressure producing means respectively for transferring the load or pressure respectively from the low to intermediate to high pressure producing means. Referring to the drawing for more speciñc de tails ofthe invention, I0 represents generally a. fluid pressure producing device including a cyl inder I2 adapted to be mounted in a fixed posi tion. The cylinder I2 has one end open and its other end closed as by a head I4 having secured thereto concentric cylinders I6 and I8 providing in conjunction with cylinder I2 large, inter mediate and small chambers 20, 22, and _724, re spectively. Cylinder I8 includes a head 26 pro vided with a discharge or outlet port 28 com municating with chamber 24. Afñxed to the cylinder IIJ is a suitable con nection 38, normally connected to a conventional An object of the invention is to provide a iiuid pressure producing device operative to in 15 fluid reservoir or tank 32 including a passage crease the fluid pressure through several stages Without increasing the applied operating force. _34 anda> chamber 36 providing communication >between-_the reservoir and chamber 20 by way of passages 3`8- and 40 in the wal1 of rcylinder |72. An object of the invention is to provide a fluid A piston 42 reciprocable in the chamber 20 is pressure producing device operative to effect a transition from low to high pressure Without per V20 held against displacement by a retaining ring ception to the operator. - v¿i4 ysecured tothe open end of the cylinder I2. . Another object of the invention is the pro vision of a ñuid pressure producing device in cluding a low pressure producing means, an in . termediate pressure producing means, and a high The-piston includes a head 46, a reduced body portion 48 providing in conjunction with the lwall of the cylinder I2 an annular chamber 50, _ an internal body portion 52“, and a skirt' 54’ sup chamber and a high pressure chamber, pistons. porting a sealing cup 56 for inhibiting seepage of fluid from the cylinder past the piston, and arrangedY in the back of the piston is a socket 5B. 'Chamber'EU communicates through passage 30 36, chamber 36 and passage> 34 with reservoir 32, reciprocable in the respective y chambers, and means in the pistons for controlling the transi in inter-communicating chambers 60 and 62 pressure producing means. A further object of theinvention is to provide a fluid pressure producing means including a low pressure chamber, an intermediate pressure tion of pressure from the low to the high pres sure chamber. A still further object of the invention is to provide a fluid pressure producing means in cluding a cylinder having small, intermediate, and large diametral bores, a piston in the cylinder having heads reciprocable in the respective bores for producing‘various stages of fluid pressure, and a valve system inthe piston adapted to be ac tuated by the fluid pressure developed in the respective bores. Other objects and advantages of the invention will appear from the following description taken in connection with the drawing forming part of this speciñcation, and in Which Fig. 1 is a diagrammatical illustration of a ñuid pressure braking system embodying the inven tion; Fig; 2 is a vertical sectional View of a fluid pressure `producing device; and . Fig. 3 is a sectional view of a modiñed form of valve system-embodied in the fluid pressure producing'device. The body portion 5'2 ofthe Vpiston 42 has there communicating With chamber 50 through a pas sage 6’4, and with chamber 20 by Way of re ’stricted passages 66 and 68; The communica "tion between chambers 60 and 62 is’controlled by a spring-pressed ball check valve l0 adapted.v to be actuated by a spring-pressed slide valve 'I2 reciprocable in chamber 62. Valve 'l2 includes a projection 'I4 for associa 40 tion with valve -III, a projection 'I6 extended through and'beyond a bore "I8 in body portion Y52 of piston 42, the purpose of which will here inafter appear, and an annular section-80 having L' A a plurality of passages Atherethrough for control of passage 68. YThe head ¿36 ci piston 42 has a plurality of ports or'passages 82 therethrough providing com munication between the annular chamber 56 and that portion of the large chamber 28 forward of the' head 46, and a sealing cup 84 is seated on the head for control of the passages. A piston 86 includes heads 88 and l90 adapted for reciprocation in the respective chambers 22 and V24; Piston 86 has a body portion 92‘te1e 2,410,169 3 4 scoping the body portion 52 of piston 42 and is loosely coupled therewith to permit free self alignment of the pistons in the respective cham bers in which they reciprocate. A lock-screw 94 threaded in the body portion 92 of piston 88 in hibits relative axial movement between pistons 42 and 86. The head 88 of piston 86 has a plu a stub shaft |52 and connected by a retractile spring |54 to a ñxed support |56. In a normal operation, upon depressing the rality of passages S6 providing communication sealing cup 84 on the head 46 of piston 42 closes between chambers 20 and 2.2, and a sealing cup the passage 40, the sealing cup 98 on the head foot pedal lever |50, force is transmitted there from through the rod |46, resulting in advancing the pistons 42 and 80 on the compression stroke. During the initial movement of the pistons, the 88 is seated on the head for control of the pas 88 of the piston 86 closesoff ports |30, the sealing sages. cup |26 on the head 90 of the piston 80 closes off port |32, and thereafter, as the pistons ad Piston 86 has in its body intercommunicating chambers |00 and |82 corresponding to cham vance on the compression stroke, a large volume of fluid is displaced from the low pressure cham bers 00 and 62 in piston 42. Chamber |00 is ber 20 through the passages 96 in the piston head closed at one end by a ring |04 threaded in the 88, past the sealing cup 98 into the intermediate body of the piston 88. The ring |04 receives and pressure chamber 22, through the passages |24 supports the projection 'I6 of valve 12 for recip on the piston head 90, past the sealing cup |20 rocation in chamber |00 and has in its wall a passage |00 providing in conjunction with a pas into the high pressure chamber 24, thence sage |08 in the body portion 52 of piston 42 com 20 through the discharge port 28 and fluid pressure delivery pipes |34 into the ñuid pressure actuated -munication between chambers 62 and |00. motors |36, causing energization of the motors The communication between chambers |00 and |02 is controlled by a spring-pressed ball check with the resultant actuation of the friction ele :ments i 42 into engagement with the drum |40 `valve ||0 adapted to be actuated by the ñuid pressure chamber 22 and also by a spring-pressed 25 against the resistance of the retractile spring |44, to take up the clearance between the friction ele slide valve ||2 mounted for reciprocation in the ments and drum. Because of the displacement chamber |02. The valve ||2 includes a plunger of a large volume of fluid, at a relatively low ||4 fitted in a bore ||6 in the head 80 of the pressure, the friction elements are moved into piston 86. A restricted passage ||8 and a pas sage |20 provide communication between cham 30 engagement with the drum quite rapidly. After a predetermined pressure has been ' bers 22 and |02, passage |20 being controlled by reached in the chamber 20, say, approximately the plunger portion of valve H2. The plunger 30 pounds per square inch, the pressure in cham ' ||4 of valve ||2 has passages |22 through its ber 20 acting on the ball Valve 'i0 by way of re body providing communication therethrough be tween passage |20 and the chamber |02. 35 stricted passage 60 and chamber 62 cracks the valve to thereby relieve pressure from chamber The head 00 of the piston 80 has a plurality of 20. ' passages |24 therethrough providing communi The fluid pressure in the large chamber 20 is cation between the chambers 22 and 24, and a thus relieved and a portion of the fluid is re sealing cup |26 seated on the head controls the passages |24, the central portion >thereof being 40 turned from the chamber through restricted pas sage 06, chambers 62 and 60, passage 64, chamber adapted to abut the plunger ||4 of valve ||2. ‘50, passage 38, chamber 36, and passage 34 to the A spring |28 interposed between the sealing reservoir 32. cup |20l and the head 20 of the cylinder i8 serves Concomitantly therewith, and upon further ad to hold the sealing cup against displacement and vance of the pistons, additional pressure will be ` also to return the pistons 42 and 86 to their developed in the intermediate pressure chamber retracted positions. Ports |30 and |82 in the 22, with the consequent displacement therefrom walls of the respective cylinders I0 and I8 pro of fluid under pressure through passages |24 in vide communication respectively between the the piston head 86, past sealing cup |26` into chambers 28 and 22, and 22 and 24 when the 50 chamber 24, thence through the discharge port pistons are in retracted position. 28 and fluid pressure delivery pipes into the fluid `A fluid pressure delivery pipe or conduit |34 pressure actuated motors |36, causing further y connected to the discharge port 28 of the cylin energization of the motors with a resultant actu der |2 has branches connected respectively to ation of the frictionvelements |42 into engage ' fluid pressure actuated motors |36, preferably arranged in pairs, one pair for actuating the 55 ment with the drums to provide for greater re tardation of the drums |40. brakes associated with the front wheels of a Upon the attainment of a predetermined pres vehicle, and another pair associated with the sure in the intermediate pressure chamber 22, brakes of the rear wheels of the vehicle. say, approximately 60 pounds per square inch, The brakes, which may be of any desirable ’ type, preferably include a ñxed support or back 60 the ball check valve ||0 will be .lifted from its seat and thus provide for relief of pressure from l ing plate |38 adapted to be secured to an axle chamber 22 through restricted passage IIB, or axle housing, a rotatable drum |40 associated chambers |00 and |02, passage |06, passages |08, » with the backing plate adapted to be secured the passages in valve 12, chamber 62, past the to a wheel, a pair of friction elements or shoes |42 pivoted on the backing plate for cooperation 65 valve 10, chamber Si),> passage |54, chamber 50, passage 38, chamber 36, and passage 34 to the Y with the drum, a retractile spring |44 connecting reservoir 32. ' the shoes, and a motor corresponding to the Simultaneously with the cracking of valvel I0 motors |36 mounted on the backing plate between providing for relief of pressure on the fluid in the shoes and operative to actuate the shoes into 70 chamber 22, the pressure is received on the' head engagement with the drum against the resistance 90 of the piston 85, and subsequent further move of the retractile spring. ment of the pistons 42 and 86 produces the high The socket 58 receives one end of a thrust rod pressure stage of operation of the unit by the |743, the other end of which is connected by a development of high pressure on the fluid in ` clevis |48 to a foot pedal lever |50 rockable on 75 chamber 24 with the consequent displacement amitiee 5 therefrom through portï28, delivery pipesv- |34 into the fluid pressure actuated motors |36, causing still further energization» offthefmotors with the resultant» actuation o_f the friction» elements-into further engagement with the drums tol thereby inhibit rotation of the drums. v Upon attainment> of a predetermined pressure, say 70 pounds per square inch, in chamber 24, actingy upon the sealing cup |26, the valve ||~2 reciprocable in chamberV |02 is moved against the resistance of the valve spring to thus abut ball 6 closed atene-‘end by a ring .3M-threaded» in the body of piston 286 havingfa passage 306 in its wal-l and providing in conjunction with a passage 308 inthe body portion »252` of the piston 242-` .com munication between chambers 262> and 300. ' The :communication between chambers 300 and 302 is controlled by a spring-pressed ball-check valve 3f|0V adapted to be actuated by- aV ‘spring pressed valve 3|2 mounted for recíprocation in 10 chamber-302. A restricted passage-3 I6 in the pis ton 286-' -provides communication betweenf- the chambers222 and 302.> ' valve H0, Which in turn abuts the projection 16 The mode of` operation of lthe modiñcation is of- slide valve 1-2, causing movementof the valve 'substantially Videntical to that of the preferred 12 against the resistance of its spring, whereby projection ‘i4 of the valyeabuts ballV valve 10 to 15 embodiment, the only difference being in they ab retain it fromits seat. With vthe movement of the ‘slide valves 'l2Y and H2 from their normal posi tions, the Vpassage 68* yin the piston 412 and the passage |20 inthe piston 36à are uncovered to sence of the slide valve operation between the ball valves-_hence needs no explanation. ` While this invention has been described in con nection With certain speciñc embodiments, Vthe thereby provide for more complete relief of" pres 20 principle involved is susceptible ofA numerous other applications that will readily occur to perf sure from chambers, 20> and 22 through the vari sons skilled inthe art. The-invention is, .there ous interconnected chambers and passages to the fore, to be limited only as indicated by the scope reservoir 32. The movement of valve 80 is in oi the appended claims. sufficient to close the restricted passage 66. The Having thus described the various features of complete relief of pressure in chambers 20 and 22 the invention, what I claim as new and desire to provides for the removal of parasitic load on the secure by Letters Patent is: head 46 of the piston 42 and the head 86 of the 1. A fluid pressure producing device having a piston 86 during the high ñuid pressure develop low pressure chamber, an intermediate pressure ment stage of operation. Upon completion of a braking operation, the 30 chamber and a high pressure chamber, a piston having heads movable inthe respective chambers foot pedal lever |50 is released and is returned for creating pressure, and a loaded valve mecha to its retracted position under the influence of nism in the piston controlled by the differential the retractile spring |54. This movement of the of fluid pressure between the low and intermedi foot pedal lever retracts the rod |46 With the ate chambers for relieving the pressure in the in resultant release of the pistons 42 and 86 and termediate pressure chamber to thereby transfer return thereof to retracted position under the in the load from the low and intermediate to the fluence of retractile spring |28. high pressure piston head. As the pistons return to retracted position, the 2. A liuid pressure producing device having a valves 10, 12, ||0, and ||2 also return to re low pressure chamber,- an intermediate pressure tracted position, and simultaneously therewith a chamber and a high pressure chamber, and a pis partial vacuum is created in chamber 24, result ton having heads movable in the respective cham ing in drawing lluid from the reservoir through bers forv creating pressure, and a valve mecha passage 34, chamber 36, and passage 38, into the nism comprising a pair of ball valves and a pair annular chamber 50, thence through the passages 82 in the head of the large piston 42, past the » of slide Valves actuated by `the fluid pressure in the chambers for consecutively relieving the pres sealing cup 84, into chamber 20, through the Das sure in the respective low and intermediate pres sages 96 in the head 88 of piston 86, past the seal sure chambers during ya pressure creating move- ' ing cup 98, into chamber 22, through the passages ment of the piston. , |24 in the head 90 of piston 86, past the sealing cup |26, into the small chamber 24, completely 50 3. A ñuid pressure producing device comprising a reservoir, a low pressure chamber, an interme filling the chambers 20, 22, and 24. diate pressure chamber and a high pressure During this operation iluid is returning to the chamber, a piston having heads movable in the chamber 24 from the fluid pressure actuated respective chambers for creating pressure, and motors |36 and the fluid pressure delivery pipes valves controlling passages lthrough the pistons |34 connecting the motors to the chamber 24. connecting the pressure chambers and reservoir, This may result in the chamber 24 receiving a said valves being normally closed the valve be quantity of fluid in excess of its capacity and in tween the low pressure «chamber and the reservoir this event the excessive quantity of ñuid is dis 'being first opened by a predetermined pressure in placed therefrom through the port |32 into the the loW pressure chamber, the Valve between the intermediate chamber 22, through port |30, into intermediate chamber and the ñrst :chamber be the large chamber 20, and thence through pas ing first opened by a predetermined differential sage 40, chamber 36, passage 34, into the reservoir of pressure between the intermediate pressure 32. chamber and the low pressure chamber, and A modiñcation of the valve system is illustrated means to mechanically hold said valves open upon in Fig. 3 wherein a piston 242 includes a body a predetermined differential between the highportion 252 having therein intercommunicating pressure chamber and vthe intermediate pressure chambers 260 and 262 communicating with a chamber. ' chamber 220 by way of a restricted passage 266. 4. A fluid pressure -producing device compris The communication between the chambers is ing |a reservoir, a 10W pressure chamber, an in controlled by spring pressure ball check valve 210. termediate pressure chamber »and a high pressure A piston 286 has .a body portion 292` telescop chamber, a piston having heads movable in the ing the body portion 252 of piston 242, and pro respective chambers for creating pressure7 said vides within the body portion intercommunicat low and intermediate chambers communicating ing chambers 300 and 302 corresponding to cham bers 260 and 262 in piston 242. Chamber 300 is 75 with the reservoir by way of restricted passages 2,410,169 7 8 in the piston, and loaded valves in the communi cation normally closing off communication,` one low pressure chamber, an intermediate pressure chamber and a high pressure chamber, a piston of said valves being- exposed on one side to the having heads movable in the respective chambers pressure of the low pressure chamber and on the forcreating pressure, said 10W and intermediate other side to the pressure of the intermediate Ul pressure chambers communicating with the reser pressure chamber. voir, and a mechanism in the piston comprising 5. A ñuid pressure producing device having a »a ball valve adapted to be actuated by the pres 10W pressure chamber, an intermediate pressure sure in the 10W pressure chamber, a ball Valve chamber and a high pressure chamber, a piston adapted to be actuated by the pressure in the having heads movable inthe respective vchambers intermediate pressure chamber, a slide valve be for creating pressure, a check Valve past which said low pressure chamber communicates With the tween the ball valves adapted to be actuated by the movement of the second-mentioned valve, and reservoir, a slide valve controlling one restricted a slide valve adapted to be actuated by the pres-_ passage from said intermediate pressure chamber sure in the high pressure chamber, said ñrst to the reservoir by way of said check valve-con 15 mentioned ball .and slide valves operable to con trolled passage and said slide valve-controlled trol the communication between the low pressure passage, said check valve normally closing the chamber and the reservoir, and said second-men communication and adapted to be fluid pressure tioned ball and slide valves operable to control actuated to provide for relief of pressure from the the communication between the intermediate respective 10W and intermediate pressure cham 20 pressure chamber and the reservoir. bers. 6. A ñuid pressure producing device having a, LUDGER E. LA BRIE.