GB2445868A

GB2445868A - Lockable device for a vehicle parking brake

Info

Publication number: GB2445868A
Application number: GB0800869A
Authority: GB
Inventors: Thomas Mayrhofer; Michael Maier
Original assignee: MAN Nutzfahrzeuge AG
Current assignee: MAN Truck and Bus SE
Priority date: 2007-01-20
Filing date: 2008-01-17
Publication date: 2008-07-23
Anticipated expiration: 2028-01-17
Also published as: GB2445868B8; GB2445868B; GB0800869D0; DE102007003074A1; DE102007003074B4

Abstract

A lockable withdrawal device (12) whose lock is electrically connected to a parking brake of a commercial vehicle. The activated parking brake remains activated when the withdrawal device (12) is open. A conductor (1) to carry the signal triggering activation of the parking brake exhibits at least two switches (8,14), each actuated by a relay (9,15). The first switch (8) can be switched, when the withdrawal device (12) is open, by a relay (9) arranged in a latching circuit (2) that serves to connect the withdrawal device (12) to the conductor (1). The other switch (14) can be switched, when the parking brake lever (13) is operated, by a relay (15) arranged in a latching circuit (3) that serves to connect the parking brake lever (13) to the conductor (1). The two switches (8,14) are configured in series in the conductor (1). An interrupter (10) is arranged in the latching circuit (2) serving to connect the withdrawal device (12). The device is intended to prevent unintended rolling of the vehicle.

Description

I

Parking Brake The invention concerns a commercial vehicle with a parking brake as generally described in claim 1.

From DE 102 49 463 Al a method and a means to control a backward rolling prevention device are known whereby an open vehicle door and standstill of the vehicle are detected. The essence of the invention is that in the presence of an open vehicle door upon the occurrence of vehicle standstill, or during vehicle standstill, the backward rolling prevention device is not activated. The invention discloses a system that relieves the driver of the need to operate the handbrake when pulling away. By maintaining (locking) the braking pressure applied by the driver, the system prevents backward rolling of the vehicle bePveen releasing the brake pedal and actually pulling away. The braking pressure is locked for the duration of a fixed or variable holding time of the system. To enable the driver to change with ease from the brake pedal to the accelerator, the holding time (i.e. lock duration) of the braking pressure may not be of a random short duration. Thus it may be possible for the driver to leave the vehicle during the holding time. When the braking pressure is subsequently released (after the driver has left the vehicle), the vehicle can roll backwards without the driver.

A means is desirable that gives the driver an additional safeguard against unintended rolling of the commercial vehicle.

The purpose of the invention is consequently to improve by technical means the safety of a commercial vehicle in this respect.

The invention solves this purpose by the characterizing features of claim 1.

According to claim 1, a lockable withdrawal device is connected to the parking brake. The withdrawal device can be an outlet apparatus of a tanker, or a backup device of a commercial vehicle body, and serve both civil and military purposes. These are only examples and by no means exclude other possibilities. The lock can be operated automatically or manually.

The electrically connected parking brake can be activated by means of a spring-loaded brake cylinder, but it can also be based on any other methods used for parking brakes. It is also conceivable that the inventive device be used together with any other service brake in a commercial vehicle. In what follows, it is assumed that a parking brake is the brake in question.

The conductor serves to apply a voltage to a solenoid valve of the parking brake and thus trigger the braking operation. For this purpose the conductor is connected to the main battery switch. The at least two switches arranged in the conductor serve to establish or interrupt the voltage supply to the solenoid valve of the parking brake by the conductor.

Arranged in the conductor is a check lamp that tells the vehicle driver that at least one withdrawal device is open or unlocked. Also arranged in the conductor are at least two latching circuits, integrated in the conductor in such a way that, in response to a certain event (open withdrawal device or applied parking brake lever), a voltage is applied to the particular latching circuit, as a result of which a relay operates and makes a switch. Since the switches are arranged in the conductor, current flow is ensured in the conductor and simultaneously through the switch in the particular latching circuit, regardless of whether the particular event is present or not.

The relays arranged in the at least two latching circuits are electrically powered and electromagneticallY acting switches and responsible for actuating the first and further switches arranged in the conductor. The parking brake lever arranged in one of the at least two latching circuits serves for manual operation of the parking brake by the vehicle driver. Arranged in one of the latching circuits is an interrupter that serves to interrupt the current flow in the latching circuit connected to the withdrawal device.

This means that to interrupt the current flow in the conductor to end the braking operation by actuation of the solenoid valve of the parking brake by the vehicle driver to move the commercial vehicle, the interrupter has to be operated. Only for operation in emergencies does the vehicle driver have a second interrupter, called an override switch, at his disposal, but with the same function as the previously mentioned interrupter.

In another embodiment of the invention, a main switch to release the parking brake is arranged ahead of the relay in the latching circuit that serves to connect the withdrawal device. The main switch is intended as a general-purpose switch, to interrupt triggering of the solenoid valve in a dangerous situation. The parking brake can then nevertheless be released, despite an open withdrawal device on the body of the commercial vehicle, so that the commercial vehicle can be moved.

In a further embodiment of the invention, the main switch is arranged as an override switch in a cab within reach of the vehicle driver.

In every situation the vehicle driver is consequently able to move the vehicle in an emergency by overriding the inventive safeguard. In this case the electrically activated parking brake is deactivated manually by operating the override switch.

In another embodiment of the invention, a check lamp is connected in the conductor in series between the two switches to indicate the opening state of the withdrawal device. The check lamp tells the vehicle driver that at least one withdrawal device is open. An acoustic, haptic or other warning device can be added to the check lamp or can replace it. It can be arranged in the cab or elsewhere.

In another embodiment of the invention, the check lamp is arranged in the latching circuit that serves to connect the withdrawal device to the conductor. But it may also be arranged elsewhere in the latching circuit.

In another embodiment of the invention, a diode to produce the latching function is arranged in the latching circuit that serves to connect the parking brake lever. The diode serves to direct the current flow in the latching circuit.

A further embodiment of the invention discloses that the conductor is connected to a main battery switch. The result of this is a constant power supply in the conductor that, when the switches are made, supplies the necessary voltage to the solenoid valve that activates the parking brake.

In a further embodiment of the invention, a solenoid valve is arranged to arrest the parking brake upon closing of the other switch in the conductor.

An additional embodiment intends that the interrupter be arranged in the cab within reach of the vehicle driver. After closing of the withdrawal device the commercial vehicle, with the parking brake deactivated by releasing the parking brake lever, can be moved only if the interrupter has first interrupted the circuit of the latching circuit that serves to connect the withdrawal device to the conductor. The interrupter can be arranged where it is easy for the vehicle driver to reach, e.g. on the dashboard or close to the gear change device.

Further features, details and advantages of the invention are evident from the following description of a preferred embodiment of said invention and the accompanying drawing, showing the following: The figure illustrates a circuit schematic of the inventive device. It shows conductor 1 with two latching circuits 2 and 3 arranged on it. Arranged at interface 4 between latching circuit 2 and conductor I is check lamp 5. Conductor I is connected to main battery switch 6 as well as solenoid valve 7 of the parking brake, which is not shown here. Arranged in latching circuit 2, for connection to conductor 1, is switch 8, which can be operated by relay 9. Latching circuit 2 also includes interrupter 10 and main switch 11. The number 12 designates a withdrawal device. As soon as the latter is opened, a voltage is applied to latching circuit 2.

Parking brake lever 13 is shown in latching circuit 3, connected by the latter to conductor 1. To activate switch 14, there is relay 15, which is activated as soon as a voltage is applied to latching circuit 3 by operation of parking brake 13. Also arranged in latching circuit 3 is diode 16.

When withdrawal device 12 of a body (not shown) of the commercial vehicle is opened, a voltage is applied to latching circuit 2. It is assumed that interrupter 10 and main switch 11 are closed. Application of the voltage to relay 9 closes switch 8. As a result, even if withdrawal device 12 were closed, switch 8 arranged in conductor I would remain closed. Since a voltage is applied to conductor 1 independently of latching circuits 2 and 3, circuits 2 and 3 each form a latching circuit. Relay 9 keeps switch 8 closed even if withdrawal device 12 is being closed, so the voltage applied to latching circuit 2 is sustained even when withdrawal device 12 is closed.

As soon as withdrawal device 12 is opened, the voltage applied to latching circuit 2 causes activation of check lamp 5. Positioning of check lamp 5 at interface 4 of latching circuit 2 and conductor I means that check lamp 5 illuminates when switch 8 is closed until interrupter 10 is pressed. When withdrawal device 12 is open, the driver activates the parking brake by parking brake lever 13 before leaving the commercial vehicle. The voltage thus initiated closes switch 14 through relay 15.

When both switches 8 and 14 are closed, conductor 1 to solenoid valve 7 is closed and the parking brake is activated. Main battery switch 6 supplies the necessary voltage to latching circuits 2 and 3 and conductor 1. Diodes 16 and 18 direct the current in conductor I and latching circuit 3.

If the vehicle driver wishes to release the braking function of the parking brake by operating parking brake lever 13, and withdrawal device 12 is still open, the braking function of the parking brake cannot be cancelled. If withdrawal device 12 is closed and parking brake lever 13 is in its normal position, the initiators of original application of voltage to latching circuits 2 and 3 are no longer there. But switches 8 and 14 nevertheless do not open because they are kept in a closed state by the voltage applied to conductor 1. If the vehicle driver wishes to cancel the effect of the parking brake, he must press interrupter 10. Latching circuit 2 is interrupted, removing the voltage that is applied to relay 9. Switch 8, configured with relay 9, opens and the current flow in conductor 1 is interrupted. Check lamp 5 also goes out as a result. Interruption of the voltage in conductor I now also opens switch 14. The voltage to solenoid valve 7 is interrupted with the result that the effect of the parking brake is cancelled. In a dangerous situation it is possible to deactivate the parking brake by interrupting latching circuit 2 in which main switch 11 is operated.

The voltage applied to latching circuits 2 and 3 and conductor 1 may be 24 V for example. Depending on the battery (not shown), a different voltage may also be applied to latching circuits 2 and 3.

List of reference numbers: I Conductor 2 Latching circuit 3 Latching circuit 4 Interface Check lamp 6 Main battery switch 7 Solenoid valve 8 Switch 9 Relay Interrupter 11 Main switch 12 Withdrawal device 13 Parking brake lever 14 Switch Relay 16 Diode 18 Diode

Claims

CLAIMS: 1. A commercial vehicle with at least one externally

accessible, lockable withdrawal device (12) whose lock is electrically connected to a parking brake of the commercial vehicle such that the activated parking brake remains activated when the withdrawal device (12) is open, characterised in that a conductor (1) to carry the signal triggering activation of the parking brake exhibits at least two switches (8,14), each actuated by a relay (9,15), whereby the first said switch (8) can be switched, when the withdrawal device (12) is open, by a relay (9) that is arranged in a latching circuit (2) serving to connect the withdrawal device (12) to the conductor (1), and the other switch (14) can be switched, when the parking brake lever (13) is operated, by a relay (15) that is arranged in a latching circuit (3) serving to connect the parking brake lever (13) to the conductor (1), and said two switches (8,14) are configured in series in the conductor (1), and that an interrupter (10) is arranged in the latching circuit (2) serving to connect the withdrawal device (12).
2. A commercial vehicle according to claim 1 characterised in that a main switch (11) to release the parking brake is arranged ahead of the relay (9) in the latching circuit (2) that serves to connect the withdrawal device (12).
3. A commercial vehicle according to claim 2 characterised in that the main switch (l 1) is arranged as an override switch in a cab within reach of the vehicle driver.
4. A commercial vehicle according to claim 1 characterised in that a check lamp (5) is connected in the conductor (1) in series between the two switches (8,14) to indicate the opening status of the withdrawal device (12).
5. A commercial vehicle according to claim 4 characterised in that the check lamp (5) is arranged in the latching circuit (2) that serves to connect the withdrawal device (12) to the conductor (1).
6. A commercial vehicle according to claim 1 characterised in that a diode (16) to produce the latching function is arranged in the latching circuit (3) that serves to connect the parking brake lever (13).
7. A commercial vehicle according to claim 1 characterised in that the conductor (1) is connected to a main battery switch (6).
8. A commercial vehicle according to claim 1 characterised in that a solenoid valve (7) is arranged to arrest the parking brake upon closing of the other switch (14) in the conductor (1).
9. A commercial vehicle according to claim I characterised in that the interrupter (10) is arranged in the cab within reach of the vehicle driver.