GB2478771A - Warning installation for air spring park brake systems - Google Patents

Warning installation for air spring park brake systems Download PDF

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Publication number
GB2478771A
GB2478771A GB1004511A GB201004511A GB2478771A GB 2478771 A GB2478771 A GB 2478771A GB 1004511 A GB1004511 A GB 1004511A GB 201004511 A GB201004511 A GB 201004511A GB 2478771 A GB2478771 A GB 2478771A
Authority
GB
United Kingdom
Prior art keywords
control valve
brakes
sensor
condition
park brake
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1004511A
Other versions
GB201004511D0 (en
Inventor
Colin Pownall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
POWNALL SECURITY SYSTEMS Ltd
Original Assignee
POWNALL SECURITY SYSTEMS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by POWNALL SECURITY SYSTEMS Ltd filed Critical POWNALL SECURITY SYSTEMS Ltd
Priority to GB1004511A priority Critical patent/GB2478771A/en
Publication of GB201004511D0 publication Critical patent/GB201004511D0/en
Publication of GB2478771A publication Critical patent/GB2478771A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/1701—Braking or traction control means specially adapted for particular types of vehicles
    • B60T8/1708—Braking or traction control means specially adapted for particular types of vehicles for lorries or tractor-trailer combinations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/26—Compressed-air systems
    • B60T13/38—Brakes applied by springs or weights and released by compressed air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/683—Electrical control in fluid-pressure brake systems by electrically-controlled valves in pneumatic systems or parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T15/00—Construction arrangement, or operation of valves incorporated in power brake systems and not covered by groups B60T11/00 or B60T13/00
    • B60T15/02—Application and release valves
    • B60T15/04—Driver's valves
    • B60T15/041—Driver's valves controlling auxiliary pressure brakes, e.g. parking or emergency brakes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring
    • B60T17/22—Devices for monitoring or checking brake systems; Signal devices

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)

Abstract

An air spring park brake system wherein the park brakes are released by system air pressure applied via a manual park brake control valve, the control valve is provided with a sensor SW1 that detects when the control valve is in a brakes-on or brakes-off condition. The sensor is arranged to activate a warning device 10 when the valve is manually placed into the brakes-off condition irrespective of system air pressure. The warning device 10 is not activated when the control valve is in manually placed in the brakes-off condition until a door sensor SW2 signals that the cab door is open. The door sensor SW2 operates a latch R2 which continues to activate the warning device until the control valve is moved to the brakes-on condition, even if the door is re-closed. The control valve sensor SW1 also controls an engine lockout R1 that prevents the engine from being started unless the sensor detects that the control valve is in the brakes-on condition. The installation may also include a jump-off warning R3, R4 in which the control valve sensor SW1 is arranged to activate an external warning device 20 should the control valve jump into the brake-off condition while the ignition is switched off.

Description

WARNING INSTALLATION FOR AIR SPRING
PARK BRAKE SYSTEMS
TECHNICAL FIELD OF THE INVENTION
This invention relates to a warning installation for commercial vehicles fitted with air spring park brakes. C')
Q BACKGROUND a)
(\J Drivers of heavy commercial vehicles sometimes forget to apply the handbrake and exit the vehicle leaving it unbraked, especially when tired or pre-occupied, or following a breakdown for example. Unbraked and unattended vehicles have been known to roll away causing accidents, some of which have been fatal.
Current aftermarket and original warning installations fitted to new commercial vehicles with air spring park brake actuators only warn the driver that they are attempting to exit the vehicle without having applied the park brake under normal operating conditions. Such installations use an air pressure switch to detect the presence of system air pressure in the spring brake control line which is fed by a manually operable park brake control valve (sometimes referred to as a handbrake). When air pressure is present the brakes operated by the spring park brake actuators are off. The air pressure switch works in conjunction with a switch on the drivers cab door to produce an audible warning if the cab door is opened with air pressure present in the spring brake control line, meaning that the spring parking brake is not applied. Applying the handbrake causes the spring park brake control line to be vented thus applying the park brakes and causing the air pressure switch to change state cancelling the warning.
Commercial vehicle spring park brakes are often described as C) being fail safe because the brakes apply on loss of system air pressure. Thus, when a vehicle has a depleted air supply the 0) spring park brakes are automatically applied. However, if system air pressure is lost due to a burst air pipe for example, the park brake alarm is silent because there is no air pressure, even if the handbrake is in the off position. In this scenario, following repair of the air pipe, there is a risk that the vehicle engine may be started to build up air pressure with the handbrake inadvertently in the off position. As air pressure builds, the spring park brakes release and an unattended vehicle rolls away. To help prevent this type of accident a mechanical low air cut off valve is sometimes fitted, so that when system air pressure is restored the valve must be manually reset before air is available to release the spring park brakes.
Another known problem with vehicles that operate in harsh abrasive environments such as in quarries, is that the manual brake control valve can "jump off" when the vehicle is parked due to wear on the valve lever indent.
The present invention seeks to provide a new and inventive form of warning installation which addresses these known problems.
SUMMARY OF THE INVENTION
The present invention proposes that in an air spring park brake system of the kind in which the park brakes are released by C) system air pressure applied via a manual park brake control valve, the control valve is provided with a sensor that detects 0) when the control valve is in a brakes-on or brakes-off condition (\J. . and the sensor is arranged to activate a warning device when the valve is manually placed into the brakes-off condition irrespective of system air pressure.
In a preferred arrangement the warning device is not activated when the control valve is in the brakes-off condition until a door sensor signals that the cab door is open. Preferably the door sensor operates a latch which continues to activate the warning device until the control valve is moved to the brakes-on condition, even if the door is re-closed.
The installation preferably includes a backup power pack which, in the absence of system power, supplies power o the warning device when the brake control valve is in the brakes-off con di t:i on.
The control valve sensor preferably also controls an engine lockout that prevents the engine from being sared unless the sensor deecs that the control valve is in the brakes-on on di t:i on.
The insallaion may also include a jump-off warning in which the control valve sensor is arranged o acivae an external warning device should the control valve jump into the brake-off condition while the ignition is switched off. C')
0) BRIEF DESCRIPTION OF THE DRAWINGS (\J
The following desCription and the accompanying drawings referred to therein are included by way of non-limiting example in order o illusrae how the invention may be pu into practice.
In the drawings: Figure 1 is a diagrammatic view of a manual air spring park brake control as used in a vehicle fitted with a warning insallaion in accordance with the invention; and Figure 2 is a CirCuit diagram of the warning insallaion which is fitted o the vehicle.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring firsIy o Fig. 1, the drawing shows a common form of hand operated park brake conroI (handbrake) used in commercial vehicles fitted with air spring park brake actuators of the kind in which the brakes are held off by system air pressure and the brakes are auomaically applied when the air pressure is removed. The park brake control includes a valve 1 which controls the supply of air pressure o the brake acuaors by means of a manually operable lever 2. When the lever is in the (Y) brakes-off position the valve causes system air pressure o be applied o the spring park brake actuators, and in the brakes-on 0) position the air pressure is removed. In the present invention (\J the park brake conroI is provided with an eIecrical sensor such as a single pole proximity switch SW1 operated by a magnet 4 attached to the lever 2. The switch changes state according to the position of the lever, i.e. whether in the brakes-on or brakes-off position. II will be appreciated that any other form of position sensor that provides a useable form of electrical oupu signal may be used.
The warning insaIIaion shown in Fig. 2 is configured using electromechanical relays for purposes of iIIusraion, bu the insallaion could equally use microprocessor control technology.
The insallaion uses four single pole change-over relays R1-R4 having the following connections: 85/86 -relay coil -common contact 87 -normally open contact 87A -normally closed contact SW1 is shown in the brakes-on position and is arranged to connect an audible warning device 10, installed in the drivers cab, to the vehicles DC negative supply BAT-in the brakes-off position. The warning device 10 will only operate when the drivers door is opened actuating a door switch SW2 which connects the device 10 to the vehicles positive supply, BAT+.
Thus, in its basic operation, the installation will provide an C) audible warning if the driver attempts to leave the cab with the brakes released, and this is totally independent of the system air 0) pressure. (\J
Relay R2 operates as a latch to maintain the audible warning, even if the door is closed again, until the brake control lever is moved to the brakes-on condition. The relay coil is connected across the warning device 10 and the relay contacts connect the warning device to BAT+ bypassing the door switch and maintaining power to the warning device 10 when the relay is en erg i se d.
A back-up power pack 12, charged from the vehicles positive supply BAT+ via link C+, causes the warning device 10 to operate if the park brake control valve is left in the brakes-off position while the vehicle is broken down due to loss of electrical power. In these circumstances the power pack 12 provides a positive voltage to the warning device 10 via connection 14, the negative connection to device 10 being completed via SW1.
As an additional safety feature, Ri prevents the vehicle engine being started unless the spring park brake control 1 is in the brakes-on position, when SW1 connects one side of the relay coil to BAT-. Operation of the vehicle ignition switch supplies a positive voltage to the other end of the coil and energises the relay to complete the engine start circuit (shown in dashed lines). This prevents accidents when system air pressure is low or depleted following a breakdown or service work, and the C) engine could have been started to drive the onboard air compressor with the brake control valve 1 inadvertently left in 0) the brakes-off position. This can happen due to the fact that system air pressure may be insufficient to operate the pressure switch used to operate conventional warning installations, which has led to tragic roll away accidents.
The warning installation also provides protection for vehicles that operate in harsh abrasive environments such as quarries where the spring park brake manual control lever can "jump off' due to wear on the valve lever indent. For this purpose an additional warning device 20 is provided external to the drivers cab under the control of relays R3 and R4. When the ignition is on and SW1 is in the brakes-off position the jump-off warning is held inactive by relay R3, which is energised via the ignition switch and SW1 to remove the positive supply from R4. When the ignition is off, R3 connects the positive supply BAT+ to the coil of R4, but the relay will not activate the device 20 as long as the brake control valve 1 is in the brakes-on position. Should the brake control jump off, however, SW1 connects the coil of R4 to the negative supply and R4 is energised, applying power via R3 to the warning device 20 to activate the external audible alarm. As shown, there is also a connection 22 from the external warning device 20 to the positive side of device 10 so that the in-cab warning device is also activated.
Whilst the above description places emphasis on the areas which are believed to be new and addresses specific problems which C) have been identified, ft is intended that the features disclosed herein may be used in any combination which is capable of 0) providing a new and useful advance in the art. (\J
* * * * * * * *

Claims (7)

  1. CLAIMS1. In an air spring park brake system of the kind in which the park brakes are released by system air pressure applied via a manual park brake control valve, the control valve is provided with a sensor that deecs when the conroI valve is in a brakes-on or brakes-off condition and the sensor is arranged o acivae a warning device when the valve is manually placed into the brakes-off condition irrespective of system air pressure.
  2. 2. An air spring park brake system according o Claim 1 in which the control valve is installed in a drivers cab provided with (Y) a cab door having a door sensor, and the warning device is no acivaed when the control valve is in the brakes-off condition (0 until he door sensor signals that the cab door is open.
  3. 3. An air spring park brake system according o Claim 2 in which the door sensor operates a latch which continues to acivae the warning device until the control valve is moved o the brakes-on condition, even if the door is re-closed.
  4. 4. An air spring park brake system according o any preceding claim which includes a backup power pack which, in the absence of system power, supplies power o the warning device when the brake control valve is in the brakes-off condition.
  5. 5. An air spring park brake system according o any preceding claim in which the control valve sensor controls an engine lockout that prevents the engine from being sared unless the control valve sensor deecs that the control valve is in the brakes-on condition.
  6. 6. An air spring park brake system according o any preceding claim which includes a jump-off warning in which the control valve sensor is arranged o acivae an exernaI warning device should the control valve jump into the brake-off condition while the ignition is switched off.
  7. 7. An air spring park brake system subsanially as C) described with reference o the drawings.(0 * * * * * * * *
GB1004511A 2010-03-18 2010-03-18 Warning installation for air spring park brake systems Withdrawn GB2478771A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1004511A GB2478771A (en) 2010-03-18 2010-03-18 Warning installation for air spring park brake systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1004511A GB2478771A (en) 2010-03-18 2010-03-18 Warning installation for air spring park brake systems

Publications (2)

Publication Number Publication Date
GB201004511D0 GB201004511D0 (en) 2010-05-05
GB2478771A true GB2478771A (en) 2011-09-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB1004511A Withdrawn GB2478771A (en) 2010-03-18 2010-03-18 Warning installation for air spring park brake systems

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2664505A1 (en) * 2012-05-17 2013-11-20 IVECO S.p.A. System for controlling the engagement of a parking brake in a pneumatic braking system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4967182A (en) * 1989-08-28 1990-10-30 Foster Bobby D Parking brake warning device for over the road tractor trailers
JPH106974A (en) * 1996-06-26 1998-01-13 Hino Motors Ltd Parking brake alarm device of tractor
GB2381511A (en) * 2001-10-31 2003-05-07 Horland Innovations Ltd Handbrake condition indicator
US20070188316A1 (en) * 2006-02-11 2007-08-16 Mr. Kevin Dean Parking brake off warning system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4967182A (en) * 1989-08-28 1990-10-30 Foster Bobby D Parking brake warning device for over the road tractor trailers
JPH106974A (en) * 1996-06-26 1998-01-13 Hino Motors Ltd Parking brake alarm device of tractor
GB2381511A (en) * 2001-10-31 2003-05-07 Horland Innovations Ltd Handbrake condition indicator
US20070188316A1 (en) * 2006-02-11 2007-08-16 Mr. Kevin Dean Parking brake off warning system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2664505A1 (en) * 2012-05-17 2013-11-20 IVECO S.p.A. System for controlling the engagement of a parking brake in a pneumatic braking system

Also Published As

Publication number Publication date
GB201004511D0 (en) 2010-05-05

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)