US3893544A — Pneumatic-hydraulic brake apparatus for a four-wh…

Claim 1

Independent Claim 237 words

A brake rigging for a four-wheel type of railway vehicle truck having two spaced-apart side frames disposed on opposite sides of a longitudinal axis and each perpendicular to a transverse axis of the truck, said brake rigging comprising: a. two brake-shoe-carrying brake beams extending in spaced substantially parallel relation to the transverse axis of the vehicle truck, and guidably supported at the ends thereof on the side frames of the truck for bodily movement longitudinally of the truck, each of said brake beams having adjacent each end thereof a cavity out of which extends in opposite directions a pair of coaxial bores, wherein the improvement comprises, b. a pair of hydraulic brake actuators each disposed between the two wheels on one side of the truck and having a pair of oppositely extending arms, the pair of arms of each actuator being disposed in the cavities at one end of said brake beams and respectively operatively connected to said brake beams, and c. a hydraulic-pneumatic master cylinder carried by one of said brake beams and operatively responsive to the application and release of pneumatic pressure to cause the supply and release of hydraulic fluid under pressure to and from said brake actuators whereby said actuators, in response to said supply of hydraulic fluid under pressure thereto, effect movement of said brake beams in opposite directions to a brake applying position with respect to said wheels of the truck.

Claim 2

Dependent Claim 237 words

A brake rigging for a four-wheel type of railway vehicle truck having two spaced-apart side frames disposed on opposite sides of a longitudinal axis and each perpendicular to a transverse axis of the truck, said brake rigging comprising: a. two brake-shoe-carrying brake beams extending in spaced substantially parallel relation to the transverse axis of the vehicle truck, and guidably supported at the ends thereof on the side frames of the truck for bodily movement longitudinally of the truck, each of said brake beams having adjacent each end thereof a cavity out of which extends in opposite directions a pair of coaxial bores, wherein the improvement comprises, b. a pair of hydraulic brake actuators each disposed between the two wheels on one side of the truck and having a pair of oppositely extending arms, the pair of arms of each actuator being disposed in the cavities at one end of said brake beams and respectively operatively connected to said brake beams, and c. a hydraulic-pneumatic master cylinder carried by one of said brake beams and operatively responsive to the application and release of pneumatic pressure to cause the supply and release of hydraulic fluid under pressure to and from said brake actuators whereby said actuators, in response to said supply of hydraulic fluid under pressure thereto, effect movement of said brake beams in opposite directions to a brake applying position with respect to said wheels of the truck.

Claim 3

Dependent Claim 42 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 1, further characterized by a hydraulic fluid reservoir, and a one-way flow check valve device controlling flow from said hydraulic fluid reservoir to said hydraulic-pneumatic master cylinder.

Claim 4

Dependent Claim 63 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 1, further characterized by valve means operatively responsive to a chosen hydraulic pressure established by said master cylinder to provide for flow of hydraulic fluid under pressure from said master cylinder to said hydraulic brake actuators to effect movement of said brake beams to said brake applying position.

Claim 5

Dependent Claim 97 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 1, further comprising: a. a hydraulic fluid reservoir, b. a one-way flow check valve device providing for flow of hydraulic fluid from said reservoir to said hydropneumatic master cylinder and preventing flow in the opposite direction, and c. valve means operatively responsive to a chosen hydRaulic pressure established by said master cylinder to provide for flow of hydraulic fluid under pressure from said master cylinder to said hydraulic brake actuators to effect movement of said brake beams to said brake applying position.

Claim 6

Dependent Claim 173 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 1, further comprising: a. a hydraulic fluid reservoir, b. a volume chamber, and c. valve means operatively responsive to a chosen hydraulic pressure established by said master cylinder from a first position in which a communication is established between said hydraulic brake actuators and said volume chamber and a communication is closed between said volume chamber and said hydraulic fluid reservoir to a second position in which said communication between said actuators and said volume chamber is closed, and said communication between said volume chamber and said hydraulic fluid reservoir is established whereby upon successive brake releases and subsequent applications, a fixed quantity of hydraulic fluid is successively released from said actuators to said volume chamber and thence from said volume chamber to said hydraulic fluid reservoir whereby said actuators are enabled to maintain a constant brake shoe clearance between said brake shoes carried by said brake beams and the vehicle wheels associated with the respective brake shoes.

Claim 7

Dependent Claim 71 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 3, further characterized by a one-way flow check valve device providing for flow from said valve means to said brake actuators, and choke means disposed in bypassing relation to said check valve device to control the rate of release of hydraulic fluid from said brake actuators and thereby the rate of release of a brake application.

Claim 8

Dependent Claim 144 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 3, further characterized in that said valve means comprises: a. a casing having a bore and a plurality of ports opening into said bore, two of which ports open at the wall surface of said bore diametrically opposite each other and are connected respectively to said hydraulic brake actuators and said hydraulic-pneumatic master cylinder, b. a grooved valve element slidably mounted in said bore and movable from a first position in which communication is closed between said two ports to a second position in which said grooved valve element establishes communication between said two ports via said groove to provide for flow of hydraulic fluid from said hydraulic-pneumatic master cylinder to said hydraulic brake actuators, and c. resilient means normally biasing said grooved valve element to said first position.

Claim 9

Dependent Claim 70 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 7, further characterized in that a third one of said plurality of ports opens at one end of said bore and is connected to said hydraulic-pneumatic master cylinder whereby said grooved valve element is moved from said first position to said second position upon the establishment of said chosen hydraulic pressure by said master cylinder.

Claim 10

Dependent Claim 207 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 7, further characterized in that a pair of said plurality of ports is connected respectively to said brake actuators and said hydraulic fluid reservoir, and said grooved valve element is provided with means which, while said valve element occupies its said first position, cooperates with one of said pair of ports of said plurality of ports in said casing that is connected to said hydraulic brake actuators to provide for flow of hydraulic fluid from said actuators to said bore in said casing, and, while said valve element occupies its said second position, cooperates with the other of sid pair said ports of said plurality of ports in said casing that is connected to said hydraulic fluid reservoir to provide for flow of hydraulic fluid from said bore in said casing to said hydraulIc fluid reservoir whereby, upon each brake release, the same quantity of hydraulic fluid is released from said brake actuators, irrespective of the quantity of hydraulic fluid supplied to said brake actuators as the result of brake shoe wear occurring during the prior brake application, thereby enabling the maintenance of constant brake shoe clearance while the brakes are released.

Claim 11

Dependent Claim 91 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 7, further characterized in that said grooved valve element comprises a cylindrical cup-shaped member having adjacent one end a peripheral annular groove, and a pair of ports, one of which is disposed adjacent said peripheral annular groove and extends from the peripheral surface of said cylindrical cup-shaped member to the interior thereof, and the other of which is disposed adjacent the other end of said member and extends from the peripheral surface thereof to said interior.

Claim 12

Dependent Claim 103 words

A brake rigging for a four-wheel type of railway vehicle truck, as recited in claim 7, further characterized in that one end of said bore in said casing is provided with internal screw threads, and a rotatable screw-threaded member has screw threaded engagement with said internal screw threads, said member having means for effecting manual rotation thereof in one direction or in an opposite direction to provide a variable volume which, while said valve element occupies its said first position, receives hydraulic fluid from said brake actuators upon effecting a brake release, said variable volume enabling the provision of variable brake shoe clearance.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-07-07	1979-01-06	1979-07-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-07-07	1983-01-06	1983-07-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-07-07	1987-01-06	1987-07-08	$7700.00	Window Closed / Lapsed

Pneumatic-hydraulic brake apparatus for a four-wheel truck

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