CA2875269A1 - Rail braking system and braking method for a rail vehicle including such a system - Google Patents

Abstract

The invention concerns a rail vehicle braking system comprising a service brake having a movable piston (8) which with a body (2) of the system delimits a service brake chamber (13) supplied by a first source, a piston rod (21) disposed in that chamber and fastened to a second side (32) of the piston turned towards that chamber, and a parking brake (7) disposed in said body and comprising a blocking device (20) disposed in that chamber and movable to act on said rod, and a movable control device (23, 24) which with said body delimits a parking brake pressure chamber (25) supplied by a second source, with said blocking and control devices which are configured to immobilize/unblock said rod so as to block/unblock said piston in a position.

Description

RAIL BRAKING SYSTEM AND METHOD OF BRAKING A VEHICLE
RAIL
COMPRISING SUCH A SYSTEM
The invention relates to the field of vehicle braking rail.
It relates more particularly to the braking systems railway vehicle with a service brake and a brake configured to act on a braking linkage.
It also relates to vehicle braking processes with such braking systems.
Railway vehicles are generally equipped with service brake having a piston movable under the effect of a fluid under pressure, the displacement of this piston causing a braking action such as that the tightening of a brake disc between two linings, or the pressure direct a sole against a wheel of the vehicle.
These brake cylinders also generally include a parking or emergency actuator that is activated in case of loss of pressure fluid under pressure and / or in case of voluntary emptying or leakage of pneumatic system. This actuator, also called parking brake, allows to ensure braking through the force of a spring replacing the force of fluid. Once this parking brake is activated, the brake remains tight in permanently.
European patent application EP 2 154 040 is known from rail braking system provided with a parking brake actuator coupled to a rail service brake cylinder. This brake cylinder has a body and a piston movable relative to the body to act on the braking linkage via a push rod.
The brake cylinder also has a pressure chamber delimited by the piston and by the body and which is connected by a conduit to a source of pneumatic pressure agent to put the piston in a service braking position.

2 The parking brake comprises a body that is distinct from the body of the brake cylinder. The body of the parking brake has an opening in at-piston screw of the service brake cylinder, which opening receives at sliding a thrust sleeve adjusting in this opening of waterproof way.
The parking brake also includes a movably mounted piston in a cylinder secured to the body and delimiting with the body a chamber of parking brake pressure. This parking brake pressure chamber is connected to another source of pneumatic pressure medium via a conduit.
The piston has in its center an orifice through which the sleeve of thrust.
The parking brake further includes springs which the piston of this parking brake to a so-called low position where the parking brake is considered to be in a working configuration.
To actuate the parking brake when the cylinder piston the service brake is in the service braking position, the pressure the parking brake (previously filled with the pressure agent pneumatic) is drained and the springs of the parking brake act then sure the piston of the parking brake, which drives the sleeve until it last comes to bear against the piston of the service brake cylinder.
The pressure chamber of the service brake cylinder can then be drained since the parking brake is activated.
The force applied by the parking brake on the brake piston of service is a direct function of the force developed by the springs.
This strength is of course the function of the stiffness and lengthening of these springs.
With this braking system, the force applied by the piston of the service brake cylinder when the parking brake is activated and the cylinder service brake is drained on the braking linkage is often inferior the force applied by the same piston when it is in the braking position of service.

3 The invention relates to a vehicle braking system with improved performance compared to braking apparatus of the prior art mentioned above, while being simple, convenient and economic.
The object of the invention is therefore, in a first aspect, a system of railway braking for a railway vehicle with brakes to at least garnish or at least one sole, comprising:
- a body ;
- a brake linkage configured to act on at least one said brake to at least one trim or at least one sole;
- a service brake having a movable brake piston report to said body to act on said braking link and delimiting with said body a service brake pressure chamber configured to be powered by a first source of pneumatic pressure agent for placing said brake piston in a service braking position; and - a parking brake configured to act on said brake piston said service brake and admitting a working configuration and a rest configuration;
said railway braking system being characterized in that:
said piston braking is disposed in said body and presents two sides, respectively a first side configured to act on said braking linkage and a second side opposite to said first side and turned towards said service brake pressure chamber;
- said service brake further comprises a piston rod arranged in said service brake pressure chamber and fixed on said second side of said brake piston;
- said parking brake is disposed in said body and comprises a locking device disposed in said brake pressure chamber of service, movable relative to said body to act on said piston rod and admitting a first position and a second position, as well as a device movable control relative to said body, delimiting with said body a parking brake pressure chamber configured to be powered by a

4 second source of pneumatic pressure agent, and admitting a position stable;
with said blocking device and said control device which are configured so that:
when said piston braking is in its braking position of service and that said parking brake is in working configuration, said control device acts on said locking device until this last immobilizes said piston rod so as to lock said piston of braking in its service braking position, said locking device being then in its second position and said control device in its stable positron; and - when said parking brake is in rest configuration, said control device acts on said locking device until this last releases said piston rod so as to unlock said piston of braking of its service braking position, said locking device thus being in his first position;
whereby the braking force applied to said wheelhouse of braking when said parking brake is in working configuration is directly as a function of the braking force applied to the said wheelhouse braking by said service brake in its service braking position, regardless of the force applied by said locking device on said piston rod.
In the braking system according to the invention, the braking piston is immobilized in the service braking position by the parking brake and in particular by its blocking device. This means that the piston of braking can be immobilized in any position, which position is linked to the race that this piston has traveled and this race depends on the effort applied during the service braking phase.
The term immobilize means that the effort applied by the brake piston on the braking linkage in the configuration of job parking brake does not decrease, or almost no.

We admit, however, some loss related to the recoil of the piston of braking, in particular the slight displacement of the piston relative to the device when the service brake pressure chamber is drained. This loss is controlled and is defined by a very slight decrease

5 of the applied force due in particular to manufacturing tolerances at a time locking device and brake piston. This decrease in effort applied on the braking linkage here is called recoil losses. A
value acceptable of these losses at the recoil is at the maximum of the order of 10% of the effort applied by the service brake at the moment the parking brake is actuated to be in working configuration.
Thanks to the invention and in particular to the configuration of the piston of braking and the parking brake, we are notably free from the springs known braking systems described above which make it possible to apply the parking brake force on the braking linkage via of piston of the service brake cylinder. So, for the same applied effort on the brake linkage when the parking brake is in the job, the braking system according to the invention is more compact than the braking of the aforementioned prior art, and also lighter.
It should be noted that the braking linkage has advantageously deformable arms whose elasticity can replace that of the springs of the known braking systems described above.
Note that the configuration of the parking brake is chosen such so that the force applied directly by the blocking device for immobilize the brake piston is not greater than the applied force by the springs on the piston of the braking systems of the prior art aforementioned; while the stress applied to the braking linkage when the parking brake of the system according to the invention is in the configuration of job is at least equal to or greater than that provided by the braking systems of the aforementioned prior art.
It will also be noted that the arrangement of the brake in the body of the system, and in particular the arrangement of the locking device in the

6 service brake pressure chamber, helps protect it from the body environment and a simple and convenient lubrication.
According to preferred features, simple, - convenient and of the system according to the invention:
- said locking device is arranged at least partially in said parking brake pressure chamber;
said locking device is disposed in a cavity of said body separate from said parking brake pressure chamber;
said locking device is formed by a locking pin and said control device is formed by a movable holding piston by said body and delimiting with said body a pressure chamber of parking brake and a spring element; with said holding piston which is configured to hold said blocking finger in its first position when said parking brake pressure chamber is energized and under pressure, first position in which said locking finger is at distance said piston rod; and with said spring element being configured for maintain said locking finger in its second position when said parking brake pressure chamber is drained, second position in which locking pin immobilizes said piston rod;
said spring element is disposed in said pressure chamber parking brake;
said spring element is disposed in a cavity of said body separate from said parking brake pressure chamber;
said locking device comprises two spring elements, one disposed in said parking brake pressure chamber and the other arranged in a cavity of said body separate from said brake pressure chamber of car park ;
said parking brake further comprises an intermediate lever of control attached to both said blocking device and said device command and configured to actuate said blocking device in response to the moving said control device;

7 said blocking device has at its distal end a at least one inclined edge configured to cooperate in a manner complementary with a toothing complementary to at least one inclined edge of said piston rod or an intermediate piece disposed between said stem piston and said locking device;
said blocking device has at its distal end a tooth with straight edges configured to cooperate in a complementary manner with complementary teeth with straight edges of said piston rod or a intermediate piece disposed between said piston rod and said device of blocking;
said service brake further comprises a mounted ratchet wheel on said piston rod and configured to mesh with said when the latter is in its second position, in order to immobilize said piston rod; and or - said parking brake further comprises a piece of manual unlocking of said parking brake when the latter is in work configuration, which unlock part is configured to act on said blocking device.
The subject of the invention is also, in a second aspect, a method braking of a railway vehicle comprising a braking system railway as described above, comprising:
- the step of supplying the parking brake pressure chamber of said system with a second source of pneumatic pressure agent to move the control device of said system to act on the blocking device of said system until the latter leaves free the braking piston of said system, the parking brake of said system being so in rest configuration;
- the step of supplying the service brake pressure chamber of said system with a first source of pneumatic pressure agent so as to put said brake piston in the service braking position;
- the step of controlling the emptying of the pressure chamber of parking brake for moving said blocking device until

8 last come immobilize said brake piston in its position of braking of service, said parking brake then being in working configuration;
and - the stage to control the emptying of said pressure chamber service brake.
The braking method according to the invention is particularly simple and convenient to implement.
We will now continue the presentation of the invention by the description of exemplary embodiments, given below for illustrative purposes and no limiting, with reference to the accompanying drawings in which:
- Figures 1 to 5 schematically illustrate the operation of a rail braking system according to the invention, which system is equipped with a pneumatic distributor and is connected to different sources pneumatic pressure agent of the vehicle, this system being respectively in different configurations;
FIG. 6 is an exploded perspective view of a first alternative embodiment of the rail braking system;
FIG. 7 is a diagrammatic sectional view of the system of rail braking illustrated in Figure 6, here assembled;
- Figures 8 and 9 are partial views of the braking system illustrated in Figures 6 and 7, respectively in a configuration working and in a configuration of rearming and / or unlocking a parking brake of this system, with in addition an enlargement of a detail in bottom right of each figure;
- Figures 10 and 11 illustrate schematically respectively second and third embodiments of the system rail braking illustrated in FIGS. 1 to 5, in the configuration of work of the parking brake that this system comprises; and - the Figures 12 to 15 are partial and schematic views of a fourth variant embodiment of the illustrated rail braking system sure Figures 1 to 5, in different configurations.
FIG. 1 schematically represents a braking system railway 1 for a railway vehicle with brake with linings or soles.

9 The rail braking system 1 comprises a body 2 forming here one cylinder at a time of service brake 6 and parking brake 7, a network of pneumatic line 3 connected to the body 2, a wheelhouse brake 4 mechanically connected to the body 2 and a brake 5 to fittings on which the brake linkage 4 is configured to act.
The body 2 here has the shape of an envelope globally closed.
The service brake 6 comprises a mobile service brake piston 8 relative to the body 2 in a first axial direction, a rod of thrust 9 movable also with respect to the body 2 in a second direction axial axis perpendicular to the first axial direction.
The braking piston 8 delimits with the body 2 a chamber of service brake pressure 13.
The brake piston 8 has two sides respectively a first side 17 configured to act on the braking linkage 4 by through the push rod 9 and a second side 18 opposite the first side 17 and facing the service brake pressure chamber 13.
The service brake 6 further comprises a toothed rod 21 fixed on the second side 18 of the brake piston 8. This notched rod 21 extends longitudinally in the first axial direction.
The brake piston 8 is configured to move in the body 2 while maintaining the service brake pressure chamber 13 relatively tight thanks to a membrane 14 disposed between this braking piston 8 and inner edges of the body 2.
The service brake 6 further comprises a fixed corner piece 10 on the first side 17 of the braking piston 8.
This corner piece 10 has a triangular section and is configured to cooperate with a set of thrust bearings 11, one of which bearing stops is connected to the body 2 while the other stops to bearings is connected to the push rod 9.

This push rod 9 is provided with a configured wear regulator to compensate for the wear of the brake linings 5 to prevent a game too much important (due to the wear of the packing) does not reduce the effort of braking.
The service brake 6 further comprises a spring 12 disposed here 5 around the thrust rod 9, between the thrust bearing which is connected to this last and the inner edge of the body 2. This spring 12 is configured to remember the stop that is connected to the push rod 9 against the piece of corner

10.
The service brake 6 further comprises a first orifice 15 arranged 10 in the body 2 and configured to allow movement of the rod of thrust 9 through this first orifice 15.
The service brake 6 further comprises a second orifice 16 formed in the body 2 and opening into the brake pressure chamber of service 13.
This service brake pressure chamber 13 is connected by a main brake pipe 53, also known as a service brake pipe, connected at this second port 16 to a source of fluid under pressure such as, for example, a pneumatic circuit.
The body 2 has a cavity 27 contiguous to the pressure chamber of the service brake 13 and in which the parking brake 7 is arranged.
The parking brake 7 comprises a locking device formed here by a locking finger 20 movable relative to the body 2 and extending according to the second axial direction.
The parking brake 7 further comprises a holding piston 23 movable relative to the body 2 and delimits with the latter a chamber of parking brake pressure 25.
This holding piston 23 has two sides, respectively a first side 31 on which is attached the locking finger 20 and a second side 32 opposite the first side 31 and facing the brake pressure chamber of parking 25.
The parking brake 7 further comprises a spring element 24 disposed between the body 2 and the second side 32 of the holding piston 23.

,

11 spring element 24 is configured to act on this holding piston 23 and by consequently on the locking finger 20.
It will be noted that the holding piston 23 and the spring element 24 form a mobile control device of the parking brake 7.
The holding piston 23 is configured to move in the body 2 while maintaining the parking brake pressure chamber 25 relatively tight thanks to a membrane (not shown) arranged between this holding piston 23 and the inner edges of the body 2.
The parking brake 7 comprises a third orifice (not shown) formed in the body 2 and opening into both the pressure chamber parking brake 25 and in the service brake pressure chamber 13, which third port is configured to allow movement of the finger of blocking through this third port.
It will be noted that the relative sealing between the pressure chamber of parking brake 25 and the service brake pressure chamber 13 is provided by the presence of a seal 33 disposed at the interface between this third port and the locking finger 20.
The parking brake 7 further comprises a fourth port 28 formed in the body 2 and opening into the brake pressure chamber of parking 25.
It should be noted that this brake pressure chamber parking 25 is connected by a parking brake line 58 connected to the level of this fourth orifice 28 to a source of fluid under pressure, such than for example a pneumatic circuit.
The parking brake 7 further comprises an unlocking piece 29 attached to the second side 32 of the holding piston 23 and opening to the outside of the body 2 through a fifth orifice (not shown) formed in this body 2 and opening into the cavity 27; so this unlocking piece 29 is accessible for manipulation from outdoors of the body 2.
The service brake 6 is disposed in the body 2 and is configured to act on the brake 5 via the brake linkage 4.

12 This brake 5 comprises a brake disc 35 (seen from above) mounted for example on an axle 36 of a railway vehicle, or directly on the wheel to brake.
This brake 5 further comprises two pads 37 each provided with a packing 38 configured to be applied to the contact of the disc 35 for reduce its speed of rotation and consequently that of the wheel to be braked, so than a fixing eyelet 39 formed opposite the surface of the garnish 38 configured to apply to the brake disc 35.
The braking linkage 4 comprises two deformable levers 40 each provided with an upper arm and a lower arm that are integral.
Each arm of the levers 40 is articulated on a central connector 41 via two pivots 42.
The lower arm of each deformable lever 40 is connected to one of the skates 37 via its fixing eyelet 39.
The upper arm of each deformable lever 40 is meanwhile connected to a respective hinge 44, 45.
The braking link 4 receives the body 2 between the upper arms deformable levers 40, at the joints 45 and 46.
The body 2 is rotatably mounted on the hinge 44 which is secured to one end of the push rod 9 while it is fixedly mounted on the articulation 45, which is directly integral with this body 2.
The braking link 4 also includes a bracket 43 secured to the central connector 41 for mounting this wheelhouse of braking 4 on the railway vehicle; so that the brake pads 37 are located on either side of the brake disk 35 (or the wheel of the vehicle Rail).
Note that the approximation of the joints 44 and 45 allows to move the pads 37 away from each other and that conversely, the distance of these joints 44 and 45 makes it possible to tighten the pads 37 on the brake disc (or on the wheel of the railway vehicle).

13 The pneumatic pipe routing network 3 comprises a main pneumatic circuit formed of a main pipe 50 which is configured to travel along the railway vehicle.
This network 3 further comprises an auxiliary tank 51 connected to the main pipe 50.
It will be noted that such an auxiliary reservoir 51 is generally present on each bogie of the railway vehicle.
The main pipe 50 is configured to convey a fluid under a first predetermined pressure, for example substantially equal to about 5.5bars. The auxiliary reservoir 51 thus comprises a fluid at a such first predetermined pressure.
The network 3 comprises, at the outlet of the auxiliary tank 51 (the main pipe 50 being connected to the inlet of this auxiliary tank 51) two separate pneumatic circuits also called first source of agent of pneumatic pressure and second source of pneumatic pressure agent, each being configured to supply the service brake 6 and / or the brake of parking 7.
The first source of pneumatic pressure agent is formed by a pressure regulator 52 (herein a pressure regulator) disposed at the outlet of the reservoir auxiliary 51 and configured to limit the pressure of the fluid flowing in this first source of pneumatic pressure agent at a second pressure determined, for example substantially equal to about 3.8 bar.
This first source of pneumatic pressure agent comprises in addition the main brake line 53 (mentioned above) connected at pressure limiter 52 and configured to convey fluid under the second predetermined pressure, which line is connected to the second port 16 of the service brake 6 to feed the chamber of pressure service brake 13.
The second source of pneumatic pressure agent is formed as for it a secondary brake line 54 connected directly in output of the auxiliary tank 51, a parking brake line 58 connected to the fourth port 28 of the parking brake 7 which opens into the

14 parking brake pressure chamber 25 for pneumatically feeding the latter.
The network 3 also comprises a distributor 55 here with three orifices and two positions, and monostable, which is interposed between the conduct of brake 54 and the parking brake line 58, with each of its conduits 54, 58 which is connected to this distributor 55.
This distributor 55 comprises a movable slide 60 and an actuator 63 which is configured to move this drawer 60.
This actuator 63 is configured to receive a signal from control 67, for example pneumatic.
This distributor 55 also comprises a return spring 64 configured to move the drawer 60 from one position to a second position position.
It will be noted that in FIGS. 1 and 2, the distributor 55 is represented in his first position, which first position is not his position by default.
In other words, the actuator 63 of the distributor 55 is configured to receive a non-zero pneumatic signal or at least sufficient to move the drawer 60 between its second position (default position also called normally closed illustrated in Figures 3 and 4) and its first position (illustrated in Figures 1 and 2).
Note that the drawer 60 has a first chamber 61 provided with three inputs / outputs 61a-c and a second chamber 62 provided also four inputs / outputs 62a-c.
In each of the first and second positions of the drawer 60, the secondary brake line 54 and the parking brake line 58 are each connected to one of the three inputs / outputs 61a-c and 62a-c.
We will now describe the operation of the braking system 1 with reference to FIGS. 1 to 5, which schematically illustrate different configurations of this system 1.
In FIG. 1, the rail braking system 1 is in a reset configuration.

In this reset configuration, the pressure chamber of service brake 13 is not powered (it is drained) so that the piston 8 is in a rest position, in which it does not apply braking force on the push rod 9.
5 By therefore, joints 44 and 45 of the braking 4 are at a distance from one another to keep shoes 37 of the brake disc 35.
The parking brake pressure chamber 25 is itself powered by the parking brake line 58, which is connected via the Distributor 55 to the secondary brake line 54, itself being directly connected to the auxiliary tank 51.
The parking brake pressure chamber 25 is therefore under pressure so that the holding piston 23 is in a first position in which the spring element 24 is compressed and the finger of blocking

15 20 in a first position remote from the notched pin 21 of the brake of service 6.
In this system reset configuration 1, the brake of parking 7 is in a rearmed configuration while the service brake 6 is in a rest configuration.
In addition, the drawer 60 of the dispenser 55 is in its first position indicating that the actuator 63 has received a command signal 67 (no zero) and therefore that the drawer 60 has been moved from its second position (position by defect) in its first position against the return spring 64, which is compressed.
In this first position of the drawer 60, the first chamber 61 has a first power input 61b connected to the reservoir 51 via the secondary brake line 54, a first parking brake output 61c in fluid communication with the first power input 61b and connected to the pressure chamber of parking brake 25 via the parking brake line 58.

16 In addition, the first chamber 61 has a first blocked orifice 61a not connected and configured to prohibit the passage of fluid if the conduct secondary brake 54 was connected to it.
None of the entry and exit of the second chamber 62 of the drawer 60 is not connected.
It will be noted that the parking brake 7 is sized and configured to so that the rearming pressure of the parking brake 7 is relatively low, for example of the order of 2bar to 6bar.
In FIG. 2, the rail braking system 1 is represented in an application configuration of the service brake 6.
In this application configuration of the service brake 6, the service brake pressure chamber 13 is powered by the conduct of main brake 53.
The service brake pressure chamber 13 is therefore under pressure and the brake piston 8 was moved in the first direction axis from its first position to a second position in which the corner piece 10 spaced the set of thrust bearings 11, thus displacing the push rod 9 and the hinge 44.
As a result, the joints 44 and 45 move away from each other and cause the approach of the pads 37 and thus the application of the packings 38 against the brake disc 35.
It will be noted that in the application configuration of the service brake 6 of the system 1, the levers 40 are deformed (elastically).
It will also be noted that in this configuration illustrated on the 2, the parking brake pressure chamber 25 is still under pressure as mentioned with reference to FIG.
In this application configuration of the service brake 6 of the system 1, the parking brake 7 is still in its rearmed configuration while the service brake 6 is in a working configuration.
The position of the drawer 60 of the distributors 55 is therefore similar to that illustrated in Figure 1.

17 It will also be noted that in the configuration illustrated in the figure 2, the first predetermined pressure of the fluid injected into the chamber of service brake pressure 13 moves the brake piston 8 of a stroke predetermined to act on the braking linkage 4 with a first strength predetermined and therefore apply a first predetermined effort on the brake disc 35.
In FIG. 3, the rail braking system 2 is represented in a lock configuration in which the brake piston 8 of the service brake 6 is immobilized in its second position illustrated on the figure 2.
Note that the braking link 4 is here in the same position as shown in Figure 2.
The service brake pressure chamber 13 is itself still under pressure while the parking brake pressure chamber 25 is drained.
The emptying of the parking brake pressure chamber 25 releases the spring member 24, which moves the holding piston 23 of its first position to a second position called stable position and so moves the finger blocking 20 from its first position to a second position in which it comes to immobilize the notched stem 21 by debridement of the distal end of this locking pin 20 with notches formed on the toothed rod 21.
To empty the brake pressure chamber of parking 25, the actuator 63 of the distributor 55 has received a control signal 67 different, here for example zero, so that the drawer 60 has gone from its first position at its second position under the action of the return spring 64.
In this second position of the drawer 60, the second chamber 62 of this drawer 60 has a second parking brake output 62c connected at the parking brake pressure chamber 25 via the parking brake line 58 and a first exhaust outlet 62a in fluidic communication with the second parking brake output 62c and leading to the atmosphere.

18 In addition, the second chamber 62 has a second orifice blocked 62b not connected.
In this system lock configuration1, the brake of parking 7 and the service brake 6 are each in a configuration of job.
In FIG. 4, the rail braking system 2 is represented in a service brake drain configuration 6.
Draining the service brake pressure chamber 13 leakage in the network 3. In other words, neither the service pressure chamber 13, nor the secondary brake line 54 and the main brake line 53 are not vented directly.
It will be noted that the fluid under pressure present in the chamber of service brake pressure 13 escapes from the latter in particular since the main brake line 53.
It should be noted that in this brake drain configuration of service 7 of the system 1, the distributor 55 has its drawer 60 in its second position.
It will also be noted that, thanks to the parking brake 6 and particular to the locking finger assembly 20 ¨ holding piston 23 - element spring 24, in combination with the toothed rod 21 attached to the brake piston of the service brake 6, this brake piston 8 remains in its second position where it acts on the braking link 4 to apply the predetermined effort sure the brake disc 35 via the pads 37, despite the emptying of the service brake pressure chamber 13.
In this configuration of draining the service brake 6, the brake of parking 7 is in a working configuration while the service brake is stuck in its working configuration, despite emptying the chamber of service brake pressure 13.
In FIG. 5, the rail braking system 1 is represented in an unlock configuration.
In this unlock configuration, an effort was applied on the unlocking part 29 of the parking brake 6 so as to pull this unlocking piece 29 towards the outside of the body 2.

19 The movement of this unlocking piece 29 causes the holding piston 23 and therefore the locking finger 20 against the spring element 24 which is thus compressed.
When the locking finger 20 reaches its second position, this last no longer cooperates with the toothed rod 21, which is free.
Therefore, the spring 12 disposed around the push rod 9 and between the inner edge of the body 2 and the thrust bearing fixed on the rod of thrust 9 returns to its original position.
This spring 12 therefore drives the thrust bearing 11 disposed between the push rod 9 and the corner piece 10 in the second direction axial, thus causing the return of the brake piston 8 in the first direction axial, to its rest position.
Joints 44 and 45 of the braking linkage are close to each other so that the deformable levers 40 found their initial positions illustrated in Figure 1 and the pads 37 is find at distance of the brake disk 35, which is thus free to rotate (the disk of brake 35 is no longer braked).
In this unlocking configuration, the parking brake 7 is in an unlocking configuration while the service brake 6 is in a rest configuration.
In the system unlock configuration 1, it will be noted that the distributor 55 is for example in the same configuration as that illustrated in Figure 4, with the service brake chambers 13 and parking 25 which are drained.
Note that the parking brake 6 is configured so that the effort to be applied for the unlocking, via the piece of unlocking 29, relatively small to be done manually by a user such as the driver of the railway vehicle. For example this effort is of the order of about 10 to 50 daN.
Figures 6 to 9 illustrate schematically and partially a first variant embodiment of the illustrated rail braking system sure Figures 1 to 5, and in particular the body and brake assembly of parking and service mounted in this body.
Generally speaking we used for similar elements the same references but added the number 100.
5 The body 102 here presents the shape of an envelope globally parallelepipedic and closed, provided with a cylindrical central cavity divided in two spaces respectively forming the brake pressure chamber of 113 and a secondary cavity 134, and a cylindrical lateral cavity or the parking brake pressure chamber 125 is formed.
10 The brake of service here includes a service brake piston 108 mobile relative to the body 102 formed for example in one piece at a time with the corner piece 110 which protrudes from the first side 131 of this piston 108 and with the piston rod 121 which projects from the second side 132 of this piston 108 in direction of the secondary cavity 134.
15 The stem of piston 121 is here provided with a threaded external surface 178.
The body 102 further comprises a flange 171 fixed in the body 102 and configured to separate the service brake pressure chamber 113 and the secondary cavity 134. This flange 171 is applied against the second side

132 of the brake piston 108.
The body 102 further comprises an annular sealing ring 170 disposed in an annular orifice 179 of the flange 171 and through which the piston rod 121 can move in translation. This ring sealing ring 170 is applied against the second side 132 of the piston braking 108.
The parking brake here comprises a holding piston 123 and a spring element 124 (FIGS. 8 and 9) arranged in the lateral cavity cylindrical in which is formed the parking brake pressure chamber 125.
observe that the holding piston 123 opens into the secondary cavity 134. The spring element 124 is configured to act on this holding piston 123.

21 The parking brake further comprises an intermediate lever of control 147 disposed in the secondary cavity 134, fixed on the one hand to the piston 123 by an end notch 149 and secondly to the body 102 by a pivot link 148 configured to allow rotational movement of the intermediate control lever 147 in response to the displacement in translation of the holding piston 123.
The assembly comprising the spring element 124, the holding piston 123 and the intermediate control lever 147 forms the device for ordered.
The parking brake 7 comprises a locking pin 120 disposed in the secondary cavity 134 of the body 102.
This locking pin 120, also called locking latch, presents a distal end a tooth 175 having a straight edge and an inclined edge, so that a flange 173 formed opposite its distal end and configured to cooperate with the intermediate control lever 147 to move in translation (raising / releasing) the locking pin 120 in response to the displacement in rotation of this intermediate control lever 147, and by consequently in response to the translational movement of the holding piston 123.
The parking brake further comprises a return spring 180 housed between the body 102 and the locking pin 120 in the secondary cavity 134.
This return spring 180 is configured to act on the locking pin 120 for the maintain in its second position when the brake pressure chamber of parking 125 is drained.
The parking brake further comprises a ratchet wheel 146 mounted on the piston rod 121. This ratchet wheel 146 has a surface internal threaded 176 configured to cooperate with the threaded outer surface 178 of the piston rod 121 to allow the translational movement of the rod of piston 121 at the same time as the rotation of the ratchet wheel 146. In other In other words, the translation of the piston rod 121 drives the ratchet wheel 146 in rotation.

22 The ratchet wheel 146 further has an outer surface on which is provided a gear 177 whose teeth each have a straight edge and inclined edge arranged to cooperate with the edges of the tooth 175 of the locking finger 120.
It will be noted that the parking brake also comprises a piece of manual unlocking (not shown) configured to act on the piston of holding 123 against the spring element 124 in order to raise the finger of blocking 120 and thus let the ratchet wheel 146 free in rotation.
In FIG. 8, the rail braking system is in its locking configuration in which the blocking finger 120 immobilizes the piston rod 108 and therefore the brake piston 108 is in its second position called service braking position.
The service brake pressure chamber 113 is under pressure while the parking brake pressure chamber 125 is drained.
The emptying of the parking brake pressure chamber 125 releases the spring element 124, which moves the holding piston 123 of its first position to a second position called stable position and so moves the intermediate control lever 147 towards the ratchet wheel 146 (down).
The locking pin 120 is thus released from the lever 147, the spring of reminder 180 relaxes and moves this blocking finger 120 of its first position towards its second position in which of the ratchet wheel 146 immobilize the ratchet wheel 146 (that is to say here prohibit the rotation in a meaning). The tooth 175 of the locking pin 120 comes to cooperate with a tooth of the tooth 176 of the ratchet wheel 146.
The immobilization of the ratchet wheel 146 makes it possible to block the displacement of the piston rod 121 in a direction opposite to the direction braking. In other words, the ratchet wheel prevents the piston rod from back towards the secondary cavity 134 opposite the chamber of service brake pressure 113.
In this service brake lock configuration, the brake parking and the service brake are each in a configuration of job.

23 The service brake pressure chamber 113 can then be drained to bring the service brake into the rest configuration, the piston of braking 108 being locked in its second position.
In FIG. 9, the rail braking system is in its unlocking and / or reset configuration in which the finger of blocking 120 and the rest of the locking device does not immobilize the stem of piston 121 and therefore the brake piston 108 returns in its first position called rest position if the service brake pressure chamber is not under pressure.
In the reset and / or unlock configuration, the service brake pressure chamber 113 is not powered (it is drained) so that the brake piston 108 is in a position of rest.
In the reset configuration, the pressure chamber of parking brake 125 is under pressure so that the holding piston 123 is in its first position in which the spring element 124 is compressed, the intermediate actuating lever 147 in the up position and the locking finger 120 in its first position away from the ratchet wheel 146.
In the unlock configuration, an effort was applied on the unlocking part of the parking brake so as to pull this piece unlocking to the outside of the body.
The displacement of this unlocking part causes the piston 123 and consequently the lever 147, which comes into contact with the flange 173 of the locking pin 120 to raise it against the return spring 180 and thus bring it away from the ratchet wheel. When the finger of blocking 20 reaches its second position, the latter no longer cooperates with the wheel ratchet 146, which is thus free (just like the piston rod 121).
Figure 10 schematically and partially illustrates another variant embodiment of the rail braking system illustrated on the figures 1 to 5 and that illustrated in Figures 6 to 9.

24 Generally speaking we used for similar elements the same references but added to the number 200 in relation to system illustrated in Figures 1 to 5 and added the number 100 by report to the system illustrated in Figures 6 to 9.
The service brake here has a ratchet wheel 246 on the rod of piston. This ratchet wheel 246 has on its external surface a toothing 276 having teeth with opposite inclined edges.
The parking brake here comprises a holding piston 223 disposed in the parking brake pressure chamber 225 and a spring element 224 also disposed in this room 225.
The parking brake further comprises a blocking device 220 formed here of two pieces, respectively a thrust piece 290 arranged in the secondary cavity 234 and attached to the holding piston 223 and a workpiece stopper 291 free in the secondary cavity 234.
The thrust piece 290 and the stop piece 291 present each a respective leading edge 292, 293 while the abutment piece 291 has, at its distal end opposite to the leading edge 293, a tooth at inclined opposite edges 275 and configured to be complementary to the toothing 276 of the ratchet wheel 246.
In FIG. 10, the rail braking system is in its lock configuration.
The parking brake pressure chamber 225 is drained and the spring element 224 relaxes and displaces the holding piston 223 which shoot in a first direction the thrust piece 290 for the latter come to bear by its leading edge 292 against the leading edge 293 of the stop piece 291. The stop piece 291 is then moved according to a second direction perpendicular to the first direction until its tooth 275 meshes with a tooth of the toothing 276 of the ratchet wheel 246 for immobilize the latter.
It will be noted that since the brake pressure chamber of parking 225 is powered and under pressure, the holding piston 223 is moves against the spring element 224 and drives the thrust piece 290 to release the stop piece 291 which no longer meshes with the wheel to ratchet 246, which is free to rotate.
Figure 11 schematically and partially illustrates another variant embodiment of the rail braking system illustrated on the figures 5 1 to 5, the one shown in FIGS. 6 to 9 and the one illustrated in FIGS.
Figure 10.
Generally speaking we used for similar elements the same references but added to the number 300 in relation to system illustrated in FIGS. 1 to 5, plus the number 200 in relation to to the system illustrated in Figures 6 to 9 and added to the number 100 by 10 to the system shown in Figure 10.
The service brake is provided with a ratchet wheel 346 on its stem.
piston. This ratchet wheel 346 has on its external surface a toothing 376 having teeth with opposite straight edges.
The parking brake here comprises a holding piston 323 arranged 15 in the parking brake pressure chamber 225 and is lacking element spring in this room.
The parking brake comprises another spring element, also called return spring 380, disposed in the secondary cavity 334 and configured to act directly on the locking pin 320.
This locking pin 320 is provided at its distal end with a tooth 375 whose opposite edges are straight to be complementary to the toothing 376 of the ratchet wheel 346.
It will be observed that holding piston 323 is here directly connected to the blocking finger 320, without intermediate control lever.

In FIG. 11, the rail braking system is in its lock configuration.
Thus, the locking pin 320 immobilizes the ratchet wheel 346. On note that due to the shape of the tooth 375 of the locking pin 320 and the tooth 376 of the ratchet wheel 346, the latter is locked in rotation in both directions of rotation.

26 Figures 12 to 15 show schematically and partially another embodiment of the illustrated rail braking system sure Figures 1 to 5, and those shown in Figures 6 to 9, 10 and 11.
Generally speaking we used for similar elements the same references but added to the number 400 in relation to the system illustrated in Figures 1 to 5, plus the number 300 in relation to to the system illustrated in Figures 6 to 9, plus the number 200 per compared to the system illustrated in Figure 10 and added the number 100 by compared to the system shown in Figure 11.
The body 402 here has the shape of an envelope globally parallelepipedic and closed, provided with a central cavity divided in two spaces respectively forming the service brake pressure chamber 413 and a secondary cavity 434, and a lateral cavity where the parking brake pressure chamber 425.
The service brake here comprises a service brake piston 408 movable relative to the body 402 and a piston rod 421 which is the second 432 side of the piston 408 towards the secondary cavity 434.
The piston rod 421 is here provided with a threaded external surface 478.
The parking brake here comprises a holding piston 423 and a first spring element 424 disposed in the lateral cavity in which is arranged the parking brake pressure chamber 425. It will be observed that the holding piston 423 opens into the secondary cavity 434. The first spring member 424 is in abutment against an inner leg 482 formed in the body 402 and is configured to act on this holding piston 423.
The holding piston 423 has an extension 487 extending in the secondary cavity 434 until coming into contact with both a intermediate device 486 and with a locking piece 420.
It will be noted that the assembly comprising the first spring element 424 and the holding piston 423 forms the control device.

27 The parking brake further comprises a second spring element 480 which bears against an internal abutment 483 formed in the body 402 and is configured to act on this blocking piece 420.
This blocking piece 420 is provided with a wall inclined on which is provided a gear 175 having teeth with at least one edge inclined.
Note that the second spring element 480 is configured to act on the locking piece 420 to maintain it in its second position when the service brake pressure chamber 425 is drained.
The parking brake further includes a ratchet wheel 446 mounted on the piston rod 421. This ratchet wheel 446 has a surface internal threaded 476 configured to cooperate with the threaded outer surface 478 of the piston rod 421 to allow the translational movement of the rod of piston 421 at the same time as the rotation of the ratchet wheel 446.
The ratchet wheel 446 further has an outer surface on which is formed a toothing 477 whose teeth each have less an inclined edge arranged to cooperate with the toothing 475 of the piece of blocking 420.
The parking brake further comprises a third spring element 481 which bears against the internal stop 483 and is configured to act on the ratchet wheel 446.
It will be noted that the parking brake also comprises a piece of manual release 429 configured to act on the blocking piece 420 and thus leave the ratchet wheel 446 free to rotate.
In FIG. 12, the system is in its configuration of reset.
In this reset configuration, the pressure chamber of service brake 413 is not powered (it is drained) so that the braking piston 408 is in its rest position.
The 425 parking brake pressure chamber is itself fed and pressurized so that the holding piston 423 is located in a first position in which the first spring element 424 is

28 compressed and the blocking piece 420 is in a first position where its inclined wall with teeth 175 is at a distance from the ratchet wheel and in particular of its external toothing 477. The second and third items springs 480 and 481 are here compressed.
In this system reset configuration, the brake of parking is in a rearmed configuration while the service brake is in a rest configuration.
In FIG. 13, the system is represented in its configuration application of the service brake.
In this application configuration of the service brake, the chamber service brake pressure 413 is supplied and under pressure and the piston braking 408 has been moved from its first position to a second position called service braking position.
Note that the piston rod 421 has moved in translation at the through the ratchet wheel 446 by generating the rotation of the latter, which is free in rotation.
It will also be noted that in this configuration illustrated on the Figure 13, the 425 parking brake pressure chamber is still under pressure as mentioned with reference to FIG.
In this application configuration of the service brake of the system, the parking brake is always in its rearmed configuration while the service brake is in a working configuration.
In FIG. 14, the system is represented in a configuration of lock in which the brake piston 408 of the service brake is immobilized in its second position illustrated in Figure 13.
The service brake pressure chamber 413 is still under pressure while the 425 parking brake pressure chamber is drained.
The emptying of the parking brake pressure chamber 425 releases the first spring member 424, which moves the holding piston 423 of its first position to a second position called stable position.

29 Thus, the extension 487 of the holding piston 423 is no longer supported against the intermediate device 486, which is then free in translation.
The third spring element 481 relaxes and drives the wheel to ratchet 446 in rotation to move it to the 487 extension until coming into stop against the toothing 475 of the locking piece 420 with which the set of teeth 477 of this ratchet wheel 446 cooperates.
The intermediate device 486 is in turn pushed in translation by the ratchet wheel 446 to the extension 487.
The ratchet wheel 446 thus comes to rest against the piece of 420 lock and therefore the piston rod 421 is also immobilized in translation.
In this service brake lock configuration, the brake parking and the service brake are each in a configuration of job.
In FIG. 15, the system is represented in a configuration of draining the service and unlocking brake.
The emptying of the service brake pressure chamber 413 through network leaks, or alternatively voluntary way.
It will be noted that thanks to the parking brake and in particular blocking piece 420 ¨ ratchet wheel 446 ¨ holding piston 423 -spring element 424, in combination with the piston rod 421 attached to the piston brake 408 of the service brake, this brake piston 408 remains in its second position despite emptying the brake pressure chamber of service 413.
In this configuration of draining the service brake, the brake of parking is in a working configuration while the service brake is blocked in its working configuration.
In the unlock configuration, an effort was applied on the unlocking part 429 of the parking brake so as to pull this piece of unlocking 429 to the outside of the body 402.
The movement of this unlocking piece 429 causes the unlocking the locking piece 420 and the second spring element 480 is relaxes and translates the blocking device 420 towards its second position.
When the locking piece 420 reaches its second position, this the last does not cooperate with the ratchet wheel 446, which is then free in 5 rotation. Therefore, the piston rod 421 is again free in translation.
In this unlocking configuration, the parking brake is in an unlocking configuration while the service brake is in a rest configuration.
In a variant not shown, the dispenser is not controlled pneumatically but rather electrically or hydraulically; and or it further comprises a threshold valve configured to control and control the passage of the dispenser drawer from a first state of the latter to a second state. Here, the first state corresponds to the first position of the drawer and the Second state corresponds to the second position of the drawer.
The threshold valve is thus configured to pass the drawer of its first position to its second position when the pressure value of the fluid under pressure in the pressure chamber of the parking brake is less than a predetermined pressure threshold value. Indeed, the triggering of the 20 threshold valve allows the emptying of the brake pressure chamber of car park and so the passage of the latter in working configuration to block the brake piston of the service brake.
It will be noted that a pressure drop is detected here in the pressure chamber of the parking brake because it is considered that such a fall of Pressure is significant of a pressure drop in the chamber of pressure the service brake. Indeed, if there are leaks in the chamber of parking brake pressure, there are also in the pressure chamber of the service brake.
The use of such a threshold valve is particularly

Advantageous because, after the application of the service brake (as described in reference to Figure 2) leaks could slowly drain the chamber of

31 service brake pressure and the parking brake pressure chamber, without that the parking brake is applied.
Thus, the threshold valve makes it possible to avoid this situation since the tilting of the drawer allows the application of the parking brake when the fluid pressure in the parking brake pressure chamber is less than the predetermined pressure threshold value (and therefore when the fluid pressure in the service brake pressure chamber has dropped significantly).
It will be observed that the actuator of the dispenser is in this case connected to the secondary brake line via a pipe of control, for the movement of the drawer at the triggering of the threshold.
In other non-illustrated variants:
- in the braking system rearming configuration railway, the resetting operation is carried out electrically or mechanical or hydraulic rather than pneumatic;
- in the unlocking configuration of the braking system rail, the unlocking part is kept in a position of unlocking the parking brake by a pneumatic or electric lock or still mechanical;
- in the unlocking configuration of the braking system rail, the unlocking control is carried out manually by the use of at least one cable, or pneumatically or electrically or else hydraulic;
- the release configuration of the braking system rail is obtained by feeding the brake pressure chamber of parking, as for rearming configuration rather than by actuating an unlocking part;
- the service brake pressure chamber can be drained voluntarily rather than by system leaks;
- locking devices and ratchet wheels and / or piston rods systems illustrated in Figures 1 to 5 and 6 to 9 may have

32 teeth like those shown on the locking devices and wheels ratchet illustrated in Figures 10 and 11;
in the locking configuration, the actuation of the device blocking can be done by an electric actuator rather than by the pressurizing a pressure chamber supplied via a distributor;
- the rail braking system is devoid of a regulator between the auxiliary tank and the service brake pressure chamber and or does not have an auxiliary reservoir and / or the first and second sources of pneumatic pressure agent are totally distinct rather than coming the same main pipe;
- the rail braking system has a service brake corner piece attached to the brake piston, so that this piston acts directly on the push rod, which acts on the levers deformable; and in this case, the brake piston together with its rod notched and the push rod are movable in the second axial direction while the parking brake is configured so that the blocking finger and the holding piston is movable in the first axial direction;
- the railway braking system has a wheelhouse of braking system different from that illustrated in the figures, in particular the wheelhouse of braking comprises a sole configured to act directly on a wheel of the railway vehicle, this sole being directly articulated by a Pivot type joint attached to the push rod, rigid lever attached to the body of the system as well as a deformable lever attached to both the rigid lever and the articulation on the sole; and or - the railway braking system comprises a wheelhouse of braking configured to act on a shoe brake as described above and is provided with a service brake with or without a corner piece attached to the piston braking.
It is recalled more generally that the invention is not limited to examples described and represented.

Claims (13)

1. Railway braking system for a railway vehicle with brakes at least one pad or at least one pad (5), comprising:
a body (2; 102; 202; 302; 402);
- a braking link (4) configured to act on at least a said brake to at least one lining or at least one sole (5);
- a service brake (6) having a brake piston (8;
;
408) movable relative to said body to act on said braking linkage (4) and delimiting with said body a service brake pressure chamber (13 ;
113; 413) configured to be powered by a first source of agent of pneumatic pressure (50, 51, 53) for bringing said brake piston into a service braking position; and a parking brake (7) configured to act on said piston of braking said service brake and admitting a working configuration and a rest configuration;
said rail braking system (1) being characterized in that:
said braking piston is disposed in said body and presents two sides, respectively a first side (17; 117) configured to act on said brake linkage (4) and a second side (18; 118) opposite said first side and facing said service brake pressure chamber;
said service brake further comprises a piston rod (21;
121; 221; 321; 421) disposed in said brake pressure chamber of service and fixed on said second side of said brake piston;
said parking brake is disposed in said body and comprises a locking device (20; 120; 220; 320; 420) disposed in said chamber service brake pressure, movable relative to said body to act on said piston rod and admitting a first position and a second position and a control device (23, 24, 123, 124, 180, 223, 280;
323, 380; 423, 424) movable relative to said body, delimiting with said body a parking brake pressure chamber (25; 125; 225; 325; 425);
configured to be powered by a second source of pressure agent pneumatic (50, 51, 54, 58), and assuming a stable position;
with said blocking device and said control device which are configured so that:
when said braking piston is in its braking position of service and that said parking brake is in working configuration, said control device acts on said locking device until this last immobilizes said piston rod so as to lock said piston of braking in its service braking position, said locking device being then in its second position and said control device in its stable positron; and when said parking brake is in the rest configuration, said control device acts on said locking device until this last releases said piston rod so as to unlock said piston of braking of its service braking position, said locking device thus being in his first position;
whereby the braking force applied to said wheelhouse of braking when said parking brake is in working configuration is directly as a function of the braking force applied to the said wheelhouse braking by said service brake in its service braking position, regardless of the force applied by said locking device on said piston rod. 2. System according to claim 1, characterized in that said blocking device (20) is arranged at least partially in said parking brake pressure chamber (25). 3. System according to claim 1, characterized in that said blocking device (120; 220; 320; 420) is arranged in a cavity (134;
;
234; 334; 434) of said body (102; 202; 302; 402) separate from said bedroom parking brake pressure (125; 225; 325; 425). 4. System according to any one of claims 1 to 3, characterized in that said locking device is formed by a finger of blocking (20; 120; 220; 320; 420) and said control device is formed by a holding piston (23; 123; 223; 323; 423) movable relative audit body and delimiting with said body a brake pressure chamber of parking and by a spring element (24; 124, 180; 280; 380; 424); with said holding piston which is configured to hold said locking finger in its first position when said parking brake pressure chamber is fed and pressurized, the first position in which said finger of blocking is remote from said piston rod; and with said element spring that is configured to hold said blocking finger in its second position when said parking brake pressure chamber is drained, second position in which said locking pin immobilizes said rod of piston. 5. System according to claim 4, characterized in that said spring element (24; 124; 424) is disposed in said pressure chamber of parking brake (25; 125; 425). 6. System according to claim 4, characterized in that said spring element (180; 280; 380) is disposed in a cavity (134; 234;
334) said body (102; 202; 302) separate from said brake pressure chamber of car park. 7. System according to claim 4, characterized in that said locking device comprises two spring elements, one disposed in said parking brake pressure chamber (125) and the other disposed in a cavity (134) of said body (102) separate from said pressure chamber of brake parking (125). 8. System according to any one of claims 1 to 7, characterized in that said parking brake further comprises a lever control intermediate (147; 247) attached to both of said blocking (120; 220) and said control device (123; 223) and configured to actuate said blocking device in response to movement of said control device. 9. System according to any one of claims 1 to 8, characterized in that said blocking device (20; 120; 220) exhibits his end distal a tooth with at least one inclined edge (175; 275) configured to cooperate in a complementary manner with a complementary toothing to at least one inclined edge (76; 176; 276; 476) of said piston rod (21;
221) or an intermediate piece (146; 446) disposed between said piston rod (21; 221) and said blocking device (20; 120; 220). 10. System according to any one of claims 1 to 8, characterized in that said blocking device (320) presents to its end distal a straight-edged tooth (375) configured to co-operate with complementary teeth with straight edges (376) of said piston rod or an intermediate piece (346) disposed between said piston rod and said locking device (320). 11. System according to any one of claims 1 to 10, characterized in that said service brake further comprises a wheel ratchet (146; 246; 346; 446) mounted on said piston rod (121; 421) and configured to mesh with said blocking device (120; 220; 320; 420) when this last is in its second position, in order to immobilize said rod of piston. 12. System according to any one of claims 1 to 12, characterized in that said parking brake (7) further comprises a part of unlocking (29; 429) manual said parking brake when the latter is in work configuration, which unlock part is configured to acting on said blocking device (20; 420). 13. Braking process of a railway vehicle comprising a rail braking system (1) according to one of the claims 1 to 9, comprising:
- the stage to feed the parking brake pressure chamber (25; 125; 225; 325; 425) of said system (1) with a second source pneumatic pressure agent (50, 51, 54, 58) for moving the device of control (23, 24; 123, 124, 180; 223, 280; 323, 380; 423, 424) of said system for acting on the blocking device (20; 120; 220; 320;
420) of said system until the latter leaves the braking piston free (8 ;
108; 408) of said system, the parking brake (7) of said system being then in rest configuration;

- the step of supplying the service brake pressure chamber (13; 113; 413) of said system with a first source of pressure agent pneumatic device (50, 51, 53) so as to put said brake piston into position service braking;
- the step of controlling the emptying of the pressure chamber of parking brake for moving said blocking device until last come immobilize said brake piston in its position of braking of service, said parking brake then being in working configuration;
and the step of controlling the emptying of said pressure chamber service brake.