Патент USA US2112356код для вставки
Patented Mar. 29, 1938 u y UNITED STATES PATENT OFFICE PRESSURE PRODUCING DEVICE . Clarence H. Bock, Detroit, Mich., assignor to i `Hydraulic Brake Company, Detroit, Mich., a corporation of California . Application December 14, 1935, SerialNo. 54,507 5 Claims. (Cl. 60-,-54.6) This invention relates t0 fluid pressure` brake ' yviding a communication between the cylinder and l systems and more particularly to fluid pressure producing devices for such systems. Heretofore in the construction of fluid pressure 5 producing devices havinga fluid reservoir, a cylinder supplied therefrom, >and a piston recip- the chamber, and this port is controlled by a valve mechanism housed in the chamber. The cylinder also has a discharge port 26 controlled by a two-way valve 28. ` 5 As shown, the valve mechanism for controlling ' rocable in the cylinder,` _the cylinder has generally the port 24 includes a double diametral'piston 3D been supplied with two ports providing communications> between the cylinder and the reservoir. reciprocable in the chamber I8 and a hollow plug 32 threaded in the open end of the chamber hav 10 These ports are generally known as the supply port and the compensating port. The latter is located slightly in advance of a flexible cup seated ing an aperture 34 providinga communication be- 10 tween the chamber and the reservoir IIJ. The plug 32 receives the small end of the piston, and on the head of the piston when the piston is in retracted position. Hence, when the piston is 15 moved on its compression stroke the pressure created in thecylinder forces the wall of_ the cup a set screw 36 in the wall of the plug limits the movement of the piston. ` » The piston has oppositely disposed heads 38 15 and 40 and a projection 42 on the head 40 hav into the port and this results in serious injury to the cup. The present invention aims to over- ing a frusto-conical end 44 adapted to seat `in the aperture 34 in the plug 32. The body of the come this objection. ` An object of the invention is to provide a com- piston and the projection 42 are axially bored to provide a chamber 46 and a passage 48 com- 20 bined supply and compensating port for a ñuid pressure producing device. municating with the chamber 46, and the passage 48 communicates `with a diametral passage ‘50 in `Another object of the invention is to provide a fluid pressure producing device including a reservoir, >a cylinder communicating therewith, a piston reciprocable in the cylinder, and means the projection 42. for control of the communication betweenr the interposed between the plug 32 and the shoulder reservoir and the cylinder so that thel commu- on the piston normally urges the piston toward nication functions as a combined supply and com- the bottom of the chamber I8 to move the ‘frus . «0 pensating port. f tro-conical end 44 on the -projection 42 from its 30 Other objects of the invention will appear from the following description taken in connection seat in the aperture 34 to establish communica tion between the reservoir I Il and the cylinder with the drawing which form a part of this spec- 22. ification, and in ‘which,-35 u A leak-proof cup 52 sleeved on the projection 42 and seated on the head 40 provides against 25 ' seepage of fluid past the piston, and a spring 54 Fig. 1 is a schematic view of a ñuid pressure brake system embodying the invention; Fig. 2 is a vertical sectional View of the ñuid pressure producing device of the system snowing the positions assumed by the parts while the sys- ’ The passage 48 is controlled by a ñap valve 56 having a restricted opening 58. A spring 60 35 interposed between the valve 56 and a ring washer 62, pressed into the open end of the chamber 46, normally urges the valve 56 to its seat, and a leakproof cup 64 held on the head 38 of the pis «i0 tem ls under pressure; and Figure 3 is an enlarged view of the mechanism ton by a spring 66 provides against seepage of 40 iluid past the piston. The valve 56 with its re lnterposed between the compression cylinder and the reservoir showing the parts in the positions assumed when the system is not under pressure. 45 Referring to the drawing for more specific de- Stl'iC’Ged Opening 58 COOpSI‘a’CeS in the Creation 0f suflicient pressure beneath the >piston valve 3U to close this valve against the resistance of the spring 54 when pressure is created in the cylin- 45 tails of the invention, IIJ represents a reservoir der 22. , having a ñlling'cpening I2 which may be closed A fluid pressure delivery pipe or conduit 68 by a plug I4 having openings I6 for venting the suitably connected to the discharge port 26 has reservoir to the atmosphere. The reservoir has 50 a dependent sleeve or chamber I8 communicating therewith and vented to the atmosphere as indicated at 20, the purpose of which will here>inafter appear. ' Acylinder 22 formed normal to the base of the chamber I8 has a port 24 adjacent its head pro- branches connected respectively to iiuid pressure actuated motors ‘I0 arranged for the actuation of 50 brakes associated with the wheels of a motor vehicle. 'I'he brakes may be of conventional type arranged in pairs, one pair for the front wheels of the vehicle and the other pair for the rear` wheels of the vehicle. ' 55 2,112,856 As shown, each of the brakes includes a fixed support or backing plate 12, a rotatable drum 14 associated therewith, a pair of corresponding interchangeable friction elements or shoes 18 pivoted on the backing plate, and a fluid pressure actuated motor corresponding to the motors 10 arranged on the backing plate and operative to ‘ t move the shoes into engagement with the drum Although this invention has been described in against the resistance of the retractile springs 18 connection with certain specific embodiments, the principles involved are susceptible of numer~ 10 10 connected between the shoes. ' A piston 80, reciprocable in the cylinder 22, is retained in the cylinder by a washer 82 seated on an annular shoulder in the open end of the cylin-' der and secured in'place by a retaining ring 84 15 seated in a groove in the wall of the cylinder. A leakproóf cup 86 seated on the head of the piston is held against displacementby a spring 88 interposed between the cup and the two-way valve 28. T'his vspring also serves to return the piston to its retracted position." > A >recessßß in the back of the piston receives one end of a thrust pin 92 on the other end of which is a cou pling 94 connected by a flexible boot 96 to the open end of the cylinder for the exclusionof dust 25 and other foreign substances. The coupling 94 is connected by a rod 98 to a foot pedal lever |00 pivoted on a suitable support |02, and the lever is connected by a retractile spring |04 to a fixed support |06. 30 v passage 48 in the piston, and the port I4 to the . reservoir. It will be observedl that should any expansionk or contraction of the fluid occur in the system due to changes in temperature, such expansion 5. or contraction is readily compensated for by the flow of fluid through the port 58 in the valve 58. ' In operation, upon depressing the foot pedal lever |08 force is transmitted from this lever to the piston 88, resulting in moving the piston on its compression stroke. During the initial move ment of the piston the fluid under pressure in ,35 the cylinder 22 and the chamber I8 causes actua tion of the piston 30 resulting in closing the port 34 and thereby cutting olf communication be tween the cylinder 22 and the reservoir. Upon further movement of the piston on its compres 40 sion stroke fluid is expelled from the cylinder 22 past the two-Way valve 28, which inhibits retrograde movement of the fluid, and through the fluid pressure delivery pipe 68 and its branches into the fluid pressure actuated motors 10, caus 45 ing actuation of the motors with the resultant spreading of the shoes 16 into engagement with the drums against the resistance of the retractile springs 18. Upon release of the foot pedal lever |00, this 50 lever is returned to its normal position under the influence of the retractile spring |04. As the foot pedal lever moves to its retracted position, the thrust pin 92 connected thereto is retracted. This results in release of the piston 80, whereupon the 55 spring 88 becomes effective to return the piston to its retracted position. Upon the initial move ment of the piston on its retraction stroke, pres sure on the piston 30 is released and the piston moves under the influence of the spring 54 to 60 its retracted position, resulting in opening the port 34 and thus establishing communication be tween the cylinder 22 and the reservoir I0. Upon further movement of the piston on its retraction stroke, fluid is drawn from the reservoir through 65 the passage 48 in the piston 30, past the valve 58 which moves downwardly to permit free flow of fluid from the reservoir to the cylinder 22, and through port 24 into the cylinder 22. During ,this operation fluid is returning to the cylinder 22 from the motors 'l0 under the in fluence of the retractile springsv'lß, and when the cylinder is filled any fluid in excess of the quanti ty required to completely lill the cylinder is re 75 turned through the port 58 in the valve 56, the ous other applications that will readily occur to persons skilled in the art. 'I'he invention is, therefore, to be limited only as indicated by the scope of the appended claims. Having thus described the various features of 15 the invention, what I claim as new and desire to secure »by Letters Patent is, 1. A fluid pressure producing device comprising a reservoir, a chamber communicating therewith, a cylinder communicating with the chamber, a 20 piston reciprocable in the cylinder, a piston valve ' reciprocable in the chamber and having a pas sage therethrough, a valve for control of the pas sage, said last mentioned valve having a restrict ed opening therethrough registering with said 25 passage, said piston valve being normally posi tioned to provide communication between the cylinder and reservoir and being responsive to the increase of pressure in the cylinder upon ad vance of the piston to close such communication, 30 and means for actuating the piston. _ 2. A iiuid pressure producing device compris Ing a reservoir, a chamber communicating there with, a cylinder communicating with the cham ber, a piston reciprocable in the cylinder, a pis ton valve in the chamber for control of the com munication between the reservoir and the cham ber, said piston valve having a passage there 35 through, said piston valve being normally posi tioned to provide communication between the 40 'reservoir and chamber but being responsive to the increase of pressure in the cylinder upon ad vance of the piston to close such communication, a spring pressed valve controlling the passage in the piston valve, said spring pressed valve having a restricted opening therethrough registering with said passage, and means for actuating the piston. *_ ' 3. A iluid pressure producing device compris ing a reservoir, a chamber communicating there with, a cylinder having an inlet port providing communication between the chamber and the reservoir and a discharge port, a piston recipro cable ln the cylinder, a piston valve in the cham ber for control of communication between the ,reservoir and chamber, said piston valve having l a passage therethrough, a spring pressed valve for control of the passage and having a com pensating port, said piston valve being normally positioned to open said inlet port but being re 60 sponsive to the increase of pressure in the cyl inde? upon advance of the piston to close ythe inlet port, and means for actuating the piston. 4. A fluid pressure producing device compris ing a reservoir, a chamber communicating there 65 with, a cylinder having an inlet port providing communication between the chamber and the reservoir and an exhaust port, a piston recip rocable in the cylinder, a piston valve in the chamber for control of the communication be tween the reservoir and the chamber and having a passage therethrough, a spring normally re taining the piston valve in inlet port opening position, a spring pressed flap valve for control of the passage in the piston valve, said flap valve 2,112,356 having a compensating port, said piston valve ‘ , 3 discharge port, a piston reciprocable in the cyl being responsive to the increase of pressure in ' inder, a piston valve in the chamber for contml the cylinder upon advance of the piston to close the inlet port, and means for actuating the pis5 to . \ ‘ 5.` A iluid pressure producing device comprising a reservoir, a chamber communicating there'11th. l cylinder having an inlet port providing a communication between the chamber and the 10 . reservoir and the discharge port, a two-way valve for `control oi the discharge port. fluid pressure actuating motors operatively connected to the of communication between the reservoir and the chamber and having a passage therethrough, a spring-pressed flap valve for control of the pas- 5 sage and having a compensating port, said pis ton valve being normally in position to open said inlet port but being responsive to the increase of pressure in the cylinder upon advance of the piston to close the inlet port, and means for ac- 10 tuating the piston. ~ CLARENCE H. BOCK.