Park release valve arrangement, brake arrangement, full trailer

Abstract

A park release valve arrangement (100) for a brake arrangement (250) of a full trailer (200) comprises a parking brake control valve (110) with an actuation member (115) for obtaining a control command (116) to control the parking brake control valve (110) and a park safe valve (120) with an inlet port (121) connected to a control line (128) for obtaining a park safe deactivation command (122). The park safe valve (120) comprises a self-holding line (123) for delivering pressurized air (125) to the parking brake control valve (110), depending on the park safe deactivation command (122), and the parking brake control valve (110) is adapted to control the brake arrangement (250) in dependence on the control command (116) and on the pressurized air (125).

Description

[0001] Park release valve arrangement, brake arrangement, full trailer

[0002] The disclosure relates to a park release valve arrangement for a brake arrangement of a full trailer. The disclosure further relates to a brake arrangement for a full trailer, comprising a park release valve arrangement, and to a full trailer, comprising a brake arrangement.

[0003] Full trailers are known in the prior art. A full trailer is also called a freight trailer and typically supported by at least front and rear axles and may be pulled by a drawbar. Full trailers are also called A-frame drawbar trailers and dog trailers. Typically, such a full trailer comprises a brake arrangement with brakes at a plurality of its axles. In particular, such a brake arrangement of a full trailer may comprise a service brake and a parking brake.

[0004] Park release valves (PRV) are known in the prior art.

[0005] WO 01 / 66376 A1 discloses a safety-enhancing automatic brake control system that automatically applies and maintains the brakes in the applied state, in response to sensors at various stations around / in the vehicle or equipment that signal a controller when conditions exist that make vehicle movement potentially dangerous. The controller validates the signals and then actuates a mechanism that manages the air, brake fluid, or mechanical brake linkage / cable that applies the brakes. The control system preferably includes a vehicle motion override system that prevents automatic application of the brakes if the vehicle is in motion above a set speed and a manual brake-releasing override that allows a driver to override the controller temporarily at the driver's discretion.

[0006] A park release valve with a so-called park-safe functionality is known. The park-safe functionality prevents the roll-away of a tractor-trailer combination during a wrong coupling procedure. However, this known valve is limited to semi-trailers and centralaxle trailers. Also, park release valves with a so-called emergency function (PREV) are known. The emergency function relates to an uncoupling of the full trailer and a tractor. However, if a driver and / or operator actuates an actuation member, e.g., a button, from a parking position to a driving position, the parking brakes of the full trailer will be released immediately and the trailer may roll away, since there is no park safe and / or positive roll-away prevention available. For example, when the full trailer is parked at a gradient and if the driver moves the button from parking to driving, a supply pressure will pressurize a spring side of a spring brake actuator and thus release the parking brake of the full trailer. Since the full trailer is parked at a gradient there is a possibility of a trailer roll-away which may result in a safety issue for at least the operator and / or the vehicle.

[0007] Further, a full trailer may comprise individually actuatable brakes, e.g., for a front axle and for a rear axle. These brakes of the front axle need to be releasable independently from the brakes of the rear axle.

[0008] It is an object of the present disclosure to provide a contribution to the state of the art and improve one or more of the above-described aspect. In particular, an object may be to provide a park safe function and an emergency function for a full trailer in an effective manner.

[0009] The object is solved by the subject-matter according to independent claim 1 and according to the remaining independent claim. Dependent claims relate to optional embodiments.

[0010] According to an aspect of the disclosure, a park release valve arrangement for a brake arrangement of a full trailer comprises a parking brake control valve with an actuation member for obtaining a control command to control the parking brake control valve and a park safe valve with an inlet port connected to a control line for obtaining a park safe deactivation command. The park safe valve comprises a selfholding line for delivering pressurized air to the parking brake control valve, depending on the park safe deactivation command, and the parking brake control valve is adapted to control the brake arrangement in dependence on the control command and on the pressurized air. The park release valve arrangement may be adapted to control a parking brake and a service brake of the full trailer, i.e. , to release and / or to lock each of the brakes. In particular, the park release valve arrangement may accomplish the release of the brakes when the full trailer is to be driven and / or moved and may accomplish a reliable locking of the brakes when the full trailer is to be parked. To control the park release valve arrangement, the control command may be obtained by the parking brake control valve, which may be functionally connected to the parking brake and to the service brake. The control command may switch between different states of the parking brake control valve, e.g., between a parking state, a driving state and a release state.

[0011] To provide a park safe functionality, the park release valve arrangement comprises the park safe valve. The park safe valve is controlled via the control line, wherein the control line may pneumatically connect the park safe valve to a tractor and / or to a control line of a tractor. Thus, the park safe valve may be adapted to receive the park safe command when the full trailer is properly connected to the tractor.

[0012] The park safe valve comprises the self-holding line which may pneumatically connect the park safe valve and the parking brake control valve to provide a further control mechanism for the functioning of the parking brake control valve. Therein, the delivery of pressurized air over the self-holding line from the park safe valve to the parking brake control valve depends on the park safe deactivation command, i.e., on the control of the park safe valve via the control line and via the inlet port of the park safe valve.

[0013] The parking brake control valve may control the brake arrangement depending on the control command and on the pressurized air being potentially delivered from the park safe valve to the parking brake control valve. The park release valve arrangement may thus control a parking and emergency brake function in a full trailer application with a park safe function. The park release valve arrangement achieves that the parking brake may not be released in response to the control command only, e.g., when a button is moved from parking to driving. Instead, the parking brake control valve may release the brakes, depending on the control command and on the pressurized air being a result of the park safe deactivation command, i.e., only after two conditions are fulfilled: one condition relating to the control command and one condition relating to the pressurized air.

[0014] In practice, a driver and / or operator needs to actuate the actuation member, e.g., from a parking position to a driving position and needs to press the foot pedal once to supply air via the control line and thus to perform a deactivation of the park safe function. Since the driver and / or operator may be within the driving cabin, the vehicle control will be with the driver which may prevent a roll-away. Otherwise, a roll-away of the trailer may be avoided by an optionally integrated emergency function. This may lead to a safe operation of the vehicle by the driver and / or operator.

[0015] Furthermore, the park release valve arrangement comprises an integrated emergency function, since the functioning of the parking brake control valve depends on the functioning of the park safe valve and thus on the park safe deactivation command via the control line.

[0016] Optionally, the parking brake control valve is adapted to retain the brake arrangement in a locked state, unless the control command is obtained by the parking brake control valve before the pressurized air is delivered to the parking brake control valve. This is an embodiment of an emergency function. The parking and / or service brake will be released only after the two aforementioned steps are completed in a pre-defined order and remains locked otherwise: first, the control command must be obtained, e.g., a switching to a driving state, and then the pressurized air is delivered, e.g., by a proper coupling between the full trailer and the tractor and the foot pedal being actuated. This achieves a park safe deactivation and a trailer roll-away is avoided.

[0017] Optionally, the park release valve arrangement comprises a positive roll-away prevention valve for enabling the parking brake control valve to control the brake arrangement. Therein, the parking brake control valve is adapted to control the parking brake and to provide an emergency function in a full trailer application with a park safe function and a positive roll-away prevention system. The positive roll-away prevention valve establishes further features of reliably controlling the parking brake control valve to control the brake arrangement. Optionally, the positive roll-away prevention valve is adapted to control the parking brake control valve in dependence on the control command. Thus, the functioning of the parking brake control valve depends on the positive roll-away prevention valve and on the control command. Thus, the actuation of the service brake and / or of the parking brake depends on the positive roll-away prevention valve and on the control command.

[0018] Optionally, the positive roll-away prevention valve is adapted to enable the parking brake control valve to release the brake arrangement only if the control command indicates a driving state of the park release valve arrangement. Thus, the park safe function will be deactivated only when the actuation member is in a driving position and optionally if a park safe deactivation command is received. Thus, the park release valve arrangement comprises an integrated emergency function, wherein the park safe function is deactivated only when, e.g., a button position is in a driving position. Thus, a driver and / or operator must follow the two-step sequence correctly, e.g., moving the button from parking to driving and then pressing a brake foot pedal to deactivate the park safe function. Subsequently, the parking and / or service brakes will be released. Conversely and optionally, the positive roll-away prevention valve is adapted to control the parking brake control valve to retain the brake arrangement locked if the control command indicates a parking state of the park release valve arrangement. By this, a trailer roll-away is prevented. It ensures a safe operation of the vehicle. The park release valve arrangement comprises both, a park safe function with positive roll-away prevention system and an integrated emergency function. Without such a positive roll-away prevention system, if the driver and / or operator presses the foot pedal first and then moves the actuation member from parking to driving, the vehicle may roll away.

[0019] Optionally, the positive roll-away prevention valve is adapted to enable the parking brake control valve to release the brake arrangement if the park safe valve receives the park safe deactivation command.

[0020] Optionally, the park release valve arrangement comprises a park safe delivery line for delivering pressurized air via the positive roll-away prevention valve and the selfholding line to the park safe valve. The self-holding line pneumatically directly interconnects the park safe valve and the positive roll-away prevention valve. Thus, the park safe valve and the parking brake control valve are pneumatically connected with each other via the self-holding line, the positive roll-away prevention valve and the park safe delivery line. Therein, the positive roll-away prevention valve may be switched according to the actuation of the park release valve arrangement. In other words, the self-holding line of park safe valve is to provide pressurized air to the park safe valve as a pilot pressure to keep the valve remaining in a park safe deactivation state and delivering pressurized air from the supply line to parking brake control valve through a connection line.

[0021] Optionally, the park release valve arrangement comprises a positive roll-away prevention pilot line from a parking brake line. This has the result that the availability of the self-holding pressure and the delivery thereof via the positive roll-away prevention valve and the park safe delivery line to the parking brake control valve depends on the pressure in the positive roll-away prevention pilot line. Therein, the parking brake line is a pneumatic line for actuating the parking brake.

[0022] Optionally, the park safe valve comprises two pilot stages for piloting the park safe valve. Therein, one of the pilot stages may comprise an inlet port being connected to the control line. This may pilot the park safe valve as described above with respect to the park safe deactivation command. The other of the pilot stages may couple the park safe valve pneumatically with the positive roll-away prevention valve. Thus, in addition to the park safe function, the positive roll-away prevention valve may sense the position of the actuation member and pilot the park safe valve accordingly, which may provide additional safety to the operator and / or the vehicle.

[0023] Optionally, the parking brake control valve and the actuation member are adapted to distinguish the following control commands: “parking”, “driving”, “release”. Therein, it is realized that one actuation member may be sufficient to distinguish the above- mentioned control commands. In contrast, in the prior art, two actuation members are provided being adapted to distinguish two control commands each, i.e. , four control commands in total, one of which may be redundant. According to an aspect of the disclosure, a brake arrangement for a full trailer comprises the park release valve arrangement as described above. Optionally, the park release valve arrangement comprises one or more optional and / or advantageous features as described above to achieve a corresponding technical effect.

[0024] According to an aspect of the disclosure, a full trailer comprises the brake arrangement as described above. Optionally, the brake arrangement and / or the park release valve arrangement of the brake arrangement comprises one or more optional and / or advantageous features as described above to achieve a corresponding technical effect.

[0025] Further advantages and technical features and their technical effects are disclosed in the figures and the description thereof.

[0026] The figures show preferred embodiments as follows:

[0027] Fig. 1 shows a schematic of a full trailer according to an aspect of the disclosure;

[0028] Fig. 2 shows a schematic of a park release valve arrangement according to the prior art;

[0029] Fig. 3 shows a schematic of a brake arrangement and of a park release valve arrangement each according to an aspect of the present disclosure; and Fig. 4 shows a schematic of a brake arrangement and of a park release valve arrangement each according to an aspect of the present disclosure.

[0030] Fig. 1 shows a schematic of a full trailer 200 according to an aspect of the disclosure. The full trailer 200 is a land vehicle. The full trailer 200 is a utility vehicle and / or a bus. The full trailer 200 comprises a front axle 210 and a rear axle 220, each of which comprises one or more wheels (not shown). The full trailer 200 is supported via the axles 210, 220 and the wheels on a ground.

[0031] The full trailer 200 comprises a coupling member 230 to mechanically couple the full trailer 200 to a tractor 300, i.e. , to a towing vehicle. The tractor 300 may move the full trailer 200 when the full trailer 200 is coupled to the tractor 300. The full trailer 200 comprises a brake arrangement 250. The brake arrangement 250 is adapted to brake the movement of the full trailer 200 and to lock the position of the full trailer 200 in a parking state. For this reason, the brake arrangement 250 comprises a park release valve arrangement 100, a service brake 255 and a parking brake 256.

[0032] The park release valve arrangement 100 is adapted to control the service brake 255 and the parking brake 256. Thus, the park release valve arrangement 100 is adapted to control the functioning of the brake arrangement 250. The park release valve arrangement 100 is pneumatically connectable to the tractor 300 via a control line 128 and a supply line 129. The park release valve arrangement 100 is adapted to receive pressurized air via the supply line 129 to supply the pressurized air to the service brake 255 and to the parking brake 256 and to receive pressurized air via the control line 128 to control the park release valve arrangement 100 and thus the service brake 255 and the parking brake 256.

[0033] The park brake arrangement 250 and the park release valve arrangement 100 is further described with reference to Figures 3 and 4.

[0034] Fig. 2 shows a schematic of a park release valve arrangement 100 according to the prior art. Fig. 2 is described under reference to Fig. 1 .

[0035] The park release valve arrangement 100 of Fig. 2 is connected to the supply line 129 and to the control line 128. The park release valve arrangement 100 is further connected to a reservoir line 140 from which the park release valve arrangement 100 may receive or supply pressurized air being provided by a reservoir (not shown) of the full trailer 200. In other words, the park release valve arrangement 100 is connected to the reservoir to receive or supply pressurized air - both is possible.

[0036] The park release valve arrangement 100 is adapted to control and is connected to the service brake 255 and the parking brake 256. To control the service brake 255 and the parking brake 256 the park release valve arrangement 100 comprises a first parking brake control function member 401 and a second parking brake control function member 402. Each of the parking brake control function members 401 , 402 comprises an actuation member 115 to control the function of the respective parking brake control function member 401 , 402 by a control command 116 as schematically indicated by the double arrows with a dashed line. The parking brake control function members 401 , 402 have the result that the service brake 255 may be operated independently from the parking brake 256, i.e. , brakes at the axle 210 may be operated independently from brakes at the rear axle 220. To release the front brakes, the actuation member 115 of the first parking brake control function member 401 may be pressed and the actuation member 115 of the second parking brake control function member 402 may be pulled.

[0037] The park release valve arrangement 100 further comprises an emergency function 400 and a bypass check valve 403 which pneumatically connects the control line 128 and the supply of the service brake 255. However, the parking brake 256 may be released by an actuation command 116 of the actuation member 115 of the second parking brake control function member 402 only. Thus, the supply pressure will pressurize a spring side of a spring brake actuator and release the parking brake 256. Thus, the park release valve arrangement 100 lacks a so-called park safe function and / or a positive roll-away prevention system.

[0038] Fig. 3 shows a schematic of a brake arrangement 250 and of a park release valve arrangement 100 each according to an aspect of the present disclosure. The park release valve arrangement 100 of Fig. 3 is a park release valve arrangement 100 for a brake arrangement 250 of a full trailer 200. Such a brake arrangement 250 and a full trailer 200 are described with reference to Fig. 1 . Fig. 3 is described under reference to Fig. 1.

[0039] The park release valve arrangement 100 of Fig. 3 is connected to the supply line 129 and to the control line 128. The park release valve arrangement 100 is further connected to a reservoir line 140 from which the park release valve arrangement 100 may receive pressurized air being provided by a reservoir (not shown) of the full trailer 200 or supply pressurized air via the reservoir line 140 to the reservoir of the full trailer 200. In other words, the park release valve arrangement 100 is connected to the reservoir to receive or supply pressurized air - both is possible. The park release valve arrangement 100 is adapted to control and is connected to the service brake 255 and the parking brake 256. To control the service brake 255 and the parking brake 256, the park release valve arrangement 100 comprises the components as described in the following.

[0040] The park release valve arrangement 100 comprises a parking brake control valve 110 with an actuation member 115 for obtaining a control command 116 to control the parking brake control valve 110. For example, the actuation member 115 may be a switch, a lever or a button which enables to distinguish between three different commands 116. The parking brake control valve 110 and the actuation member 115 are adapted to distinguish the following control commands 116: “parking”, “driving”, “release”. Fig. 3 shows the parking brake control valve 110 in a driving state, i.e. , the control command 116 “driving” is obtained. If the actuation member 115 is pressed, the parking brake control valve 110 transitions into a parking state, i.e., the control command 115 “parking” is obtained. Otherwise, if the actuation member 115 is pulled, the parking brake control valve 110 transitions into a releasing state, i.e., the control command 115 “release” is obtained. In the driving state, all brakes of all axles 210, 220 may be operated by the service brake 255. In the parking state, the service brake 255 may be released and the parking brake 256 acts on the rear axle 220. Thus, brakes of the front axle 210 and the rear axle 220 are individually actuatable.

[0041] The parking brake control valve 110 is pneumatically connected to the parking brake 256 via a parking brake line 2-2 (schematically indicated) for controlling the parking brake 256. The service brake 255 is pneumatically connected to the park release valve arrangement 100 via a service brake line 2-1 for controlling the service brake 255.

[0042] The park release valve arrangement 100 comprises a switchable check valve 132. The switchable check valve 132 is adapted to pneumatically connect the reservoir line 140 with the parking brake control valve 110 and is piloted by the reservoir line 140, wherein the park release valve arrangement 100 comprises a supply check valve 134 pneumatically arranged between the supply line 129 and the reservoir line 140, and the pilot of the switchable check valve 132 is arranged in relation to the supply line 129 after the supply check valve 134. The switchable check valve 132 prevents a loss of air in a spring side of the parking brake 256.

[0043] The park release valve arrangement 100 comprises an emergency function valve 131. The emergency function valve 131 provides an emergency function, i.e., the emergency function valve 131 prevents releasing the service brake 255, if, e.g., a supply of pressurized air 125 to the park release valve arrangement 100 is absent and / or less than a preset value but pressurized air is supplied from the reservoir line 140. The emergency function valve 131 is a switchable valve being piloted, in the driving state, by the pressurized air 125 by the supply line 129 when the park safe function is in a deactivated condition, and being piloted, in the parking state and / or in the release state, by the reservoir line 140. In the driving state, the service brake 255 is pneumatically connected to the emergency function valve 131 to control the service brake 255 via the control line 128.

[0044] The park release valve arrangement 100 comprises a park safe valve 120 with an inlet port 121 connected to the control line 128 for obtaining a park safe deactivation command 122, i.e., to define the deactivated condition of the park safe function. The park safe valve 120 is a switchable valve. The park safe valve 120 is connected to the supply line 129. The park safe valve 120 is piloted by the control line 128. The control line 128 is adapted to deliver a park safe deactivation command 122 to the park safe valve 120, e.g., the park safe deactivation command 122 may be pressurized air to release the parking brake of the tractor 300.

[0045] The park safe valve 120 of Fig. 3 comprises two pilot stages 126 (not indicated in Fig. 3) for piloting the park safe valve 120. One of the pilot stages 126 of the park safe valve 120 is connected to the control line 128. The other of the pilot stages 126 is connected to a self-holding line 123.

[0046] The park safe valve 120 comprises the self-holding line 123. The self-holding line 123 pneumatically connects the park safe valve 120 and the parking brake control valve 110. Therein, the status of the self-holding line 123 depends on the park safe deactivation command 122 and on the supply line 129. I.e., the self-holding line 123 is adapted to deliver pressurized air 125 to the parking brake control valve 110 in dependence on the park safe deactivation command 122 and on the availability of pressurized air via the supply line 129. The self-holding line 123 is a further pilot stage of the park safe valve 120.

[0047] The parking brake control valve 110 is adapted to control the brake arrangement 250 in dependence on the control command 116 and on the pressurized air 125. That is, the control of the brake arrangement 250, i.e. , of the service brake 255 and of the parking brake 256, depends on both, the control command 116 and the pressurized air 125 being delivered via the self-holding line 123 from the park safe valve 120 to the parking brake control valve 110.

[0048] The parking brake control valve 110 is adapted to retain the brake arrangement 250 in a locked state, unless the control command 116 is obtained by the parking brake control valve 110 before the pressurized air 125 is delivered to the parking brake control valve 110, here from the supply line 129. In Fig. 3, to release the brake arrangement 250, an operator needs to transition the actuation member 116 from the parking state to the driving state and subsequently press the foot pedal once to issue a park safe deactivation command 122 via the control line 128.

[0049] Fig. 4 shows a schematic of a brake arrangement 250 and of a park release valve arrangement 100 each according to an aspect of the present disclosure. The park release valve arrangement 100 of Fig. 4 is a park release valve arrangement 100 for a brake arrangement 250 of a full trailer 200. Such a brake arrangement 250 and a full trailer 200 are described with reference to Fig. 1 . Fig. 4 shows a further embodiment of the disclosure. Fig. 4 is described under reference to Figs. 1 and 3, wherein the differences between the embodiments of Figs. 3 and 4 are described.

[0050] The park release valve arrangement 100 comprises the parking brake control valve 110, the emergency function valve 131 and the switchable check valve 132 as described with reference to Fig. 3. Further, the park release valve arrangement 100 of Fig. 4 comprises a positive roll-away prevention valve 130 and a bypass check valve 133. The park safe valve 120 of Fig. 4 differs from the park safe valve 120 of Fig. 3 as described in the following. The bypass check valve 133 connects the control line 128 with the service brake 255. The bypass check valve 133 provides a bypass for controlling the service brake 255 over the other valves 110, 120, 130. The bypass check valve 133 enables a direct actuation of the service brake 255, depending on the park safe deactivation command 122.

[0051] The park safe valve 120 of Fig. 4 comprises two pilot stages 126 for piloting the park safe valve 120. Therein, one pilot stage 126 corresponds to the inlet port 121 as described with reference to Fig. 3. That is, one of the pilot stages 126 of the park safe valve 120 of Fig. 4 is connected to the control line 128. The other of the pilot stages 126 is, depending on the state of the park safe valve 120, connected to the positive roll-away prevention valve 130 or to the self-holding line 123.

[0052] The positive roll-away prevention valve 130 is adapted to enable the parking brake control valve 110 to control the brake arrangement 250, i.e. , to control the service brake 255 and the parking brake 256. The positive roll-away prevention valve 130 is adapted to control the brake arrangement 250 in dependence on the control command 116. The park release valve arrangement 100 comprises a positive rollaway prevention pilot line 136 from the parking brake line 2-2. In addition, the positive roll-away prevention valve 130 is connected to and piloted by a supply port (not indicated) of the parking brake control valve 110, wherein the supply from the parking brake control valve 110 depends on the control command 116. In particular, the positive roll-away prevention valve 130 is adapted to enable the parking brake control valve 110 to release the brake arrangement 250 only if the control command 116 indicates a driving state of the park release valve arrangement 100. Conversely, the positive roll-away prevention valve 130 is adapted to control the parking brake control valve 110 to retain the brake arrangement 250 in its locked state if the control command 116 indicates a parking state of the park release valve arrangement 100.

[0053] The park release valve arrangement 100 comprises a park safe delivery line 135 for delivering pressurized air 125 via the positive roll-away prevention valve 130 and via the self-holding line 123 to the park safe valve 120. Thus, the positive roll-away prevention valve 130 controls the state of the self-holding line 123. Depending on the piloting of the positive roll-away prevention valve 130 by positive roll-away prevention pilot line 136 and a supply pressure from supply port 129 through connection line 124, park safe delivery line 135 and park safe valve 120 of parking brake control valve 110, the self-holding line 123 may be exhausted or the pressurized air supplied to park safe valve 120 for the second pilot stage 126 through the self-holding line 123 to keep the park safe valve 120 remaining in a park safe deactivated state.

[0054] The park safe valve 120 comprises a port (not indicated) which is connected via a connection line 124 to the parking brake control valve 110 and via the park safe delivery line 135 to the positive roll-away prevention valve 130.

[0055] The park safe valve 120 and positive roll-away prevention valve 130 are adapted to release the parking brake 256 and / or the service brake 255 only when the actuation member 115 is in a “driving” state and driver and / or operator is inside the cabin of the and presses the foot pedal.

[0056] The function of park safe valve 120 and positive roll-away prevention valve 130 is to release the parking brake 256 and / or the service brake 255 only when the actuation member 115 is in a driving position and driver and / or operator of the vehicle 200 is inside the cabin and presses the foot pedal. The positive roll-away prevention valve 130 is adapted to control the park release valve arrangement 100 in dependence on the position of actuation member 115, on the availability of pressurized air in form of the park safe deactivation command 122 and on the availability of pressurized air from the supply line 129. The self-holding line 123 is adapted to keep the park safe deactivation condition. If all the above three conditions are available, i.e. , the position of actuation member 115, the availability of pressurized air in form of the park safe deactivation command 122 and the availability of pressurized air from the supply line 129, only then the positive roll-away prevention valve 130 will supply self-hold pressurized air to the park safe valve 120 the second of the pilot stages 126 (in Fig. 4, the lower pilot stage 126). If all the above three conditions are met, only then the positive roll-away prevention valve 130 will give self-holding pressurized air supply to the park safe valve 120 through the second pilot stage 126.

[0057] That is, the park release valve arrangement 100 deactivates the park safe function only when the actuation member 115 is in the driving state. Thus, an operator has to follow a two-step sequence correctly to deactivate the part safe function: moving the actuation member 115 from the parking state to the driving state and then issuing a park safe deactivation command 122, e.g., by getting into a cabin of the tractor 300 and pressing a brake foot pedal. Subsequently, the parking brakes 256 and / or the service brakes 255 will be released. In this way, the full trailer 200 roll-away is prevented.

[0058] List of reference signs (Part of the description)

[0059] 100 park release valve arrangement

[0060] 110 parking brake control valve

[0061] 115 actuation member

[0062] 116 control command

[0063] 120 park safe valve

[0064] 121 inlet port

[0065] 122 park safe deactivation command

[0066] 123 self-holding line

[0067] 124 connection line

[0068] 125 pressurized air

[0069] 126 pilot stage

[0070] 128 control line

[0071] 129 supply line

[0072] 130 positive roll-away prevention valve

[0073] 131 emergency function valve

[0074] 132 switchable check valve

[0075] 133 bypass check valve

[0076] 134 supply check valve

[0077] 135 park safe delivery line

[0078] 136 positive roll-away prevention pilot line

[0079] 140 reservoir line

[0080] 2-1 service brake line

[0081] 2-2 parking brake line

[0082] 200 full trailer

[0083] 210 front axle

[0084] 220 rear axle

[0085] 230 coupling member brake arrangement service brake parking brake tractor emergency function first parking brake control function member second parking brake control function member bypass check valve

Claims

Claims1. Park release valve arrangement (100) for a brake arrangement (250) of a full trailer (200), comprising- a parking brake control valve (110) with an actuation member (115) for obtaining a control command (116) to control the parking brake control valve (110) and- a park safe valve (120) with an inlet port (121) connected to a control line (128) for obtaining a park safe deactivation command (122), wherein- the park safe valve (120) comprises a self-holding line (123) for delivering pressurized air (125) to the parking brake control valve (110), depending on the park safe deactivation command (122), and- the parking brake control valve (110) is adapted to control the brake arrangement (250) in dependence on the control command (116) and on the pressurized air (125).

2. Park release valve arrangement (100) as claimed in claim 1 , wherein the parking brake control valve (110) is adapted to retain the brake arrangement (250) in a locked state, unless the control command (116) is obtained by the parking brake control valve (110) before the pressurized air (125) is delivered to the parking brake control valve (110).

3. Park release valve arrangement (100) as claimed in claim 1 or 2, wherein the park release valve arrangement (100) comprises a positive roll-away prevention valve (130) for enabling the parking brake control valve (110) to control the brake arrangement (250).

4. Park release valve arrangement (100) as claimed in claim 3, wherein the positive roll-away prevention valve (130) is adapted to control the brake arrangement (250) in dependence on the control command (116).

5. Park release valve arrangement (100) as claimed in claim 3 or 4, wherein the positive roll-away prevention valve (130) is adapted to enable the parking brake control valve (110) to release the brake arrangement (250) only if the control command (116) indicates a driving state of the park release valve arrangement (100).

6. Park release valve arrangement (100) as claimed in any one of claims 3 to 5, wherein the positive roll-away prevention valve (130) is adapted to enable the parking brake control valve (110) to release the brake arrangement (250) if the park safe valve (120) receives the park safe deactivation command (122).

7. Park release valve arrangement (100) as claimed in any one of claims 3 to 6, wherein the positive roll-away prevention valve (130) is adapted to control the parking brake control valve (110) to retain the brake arrangement (250) in a or the locked state if the control command (116) indicates a parking state of the park release valve arrangement (100).

8. Park release valve arrangement (100) as claimed in any one of claims 3 to 7, wherein the park release valve arrangement (100) comprises a park safe delivery line (135) for delivering pressurized air (125) via the positive roll-away prevention valve (130) and the self-holding line (123) to the park safe valve (120).

9. Park release valve arrangement (100) as claimed in any one of claims 3 to 8, wherein the park release valve arrangement (100) comprises a positive roll-away prevention pilot line (136) from a parking brake line (2-2).

10. Park release valve arrangement (100) as claimed in any one of the preceding claims, wherein the park safe valve (120) comprises two pilot stages (126) for piloting the park safe valve (120).11 . Park release valve arrangement (100) as claimed in any one of the preceding claims, wherein the parking brake control valve (110) and the actuation member (115) are adapted to distinguish the following control commands (116): “parking”, “driving”, “release”.

12. Brake arrangement (250) for a full trailer (200), comprising the park release valve arrangement (100) as claimed in any one of the preceding claims.

13. Full trailer (200), comprising the brake arrangement (250) as claimed in claim 12.

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