WO2015021050A2 - Braking system with non-spring parking brake actuator - Google Patents

Braking system with non-spring parking brake actuator Download PDF

Info

Publication number
WO2015021050A2
WO2015021050A2 PCT/US2014/049796 US2014049796W WO2015021050A2 WO 2015021050 A2 WO2015021050 A2 WO 2015021050A2 US 2014049796 W US2014049796 W US 2014049796W WO 2015021050 A2 WO2015021050 A2 WO 2015021050A2
Authority
WO
WIPO (PCT)
Prior art keywords
parking
pushrod
fluid
clutch
service
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.)
Ceased
Application number
PCT/US2014/049796
Other languages
French (fr)
Other versions
WO2015021050A3 (en
Inventor
Ronald S. Plantan
Charles E. Eberling
Fred W. Hoffman
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.)
Bendix Commercial Vehicle Systems LLC
Original Assignee
Bendix Commercial Vehicle Systems LLC
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 Bendix Commercial Vehicle Systems LLC filed Critical Bendix Commercial Vehicle Systems LLC
Priority to RU2016102996A priority Critical patent/RU2633033C2/en
Priority to AU2014306066A priority patent/AU2014306066B2/en
Priority to CN201480044461.7A priority patent/CN105518332B/en
Priority to CA2920255A priority patent/CA2920255C/en
Priority to DE112014003649.8T priority patent/DE112014003649B4/en
Publication of WO2015021050A2 publication Critical patent/WO2015021050A2/en
Publication of WO2015021050A3 publication Critical patent/WO2015021050A3/en
Anticipated expiration legal-status Critical
Ceased 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
    • 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
    • B60T13/36—Compressed-air systems direct, i.e. brakes applied directly 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
    • B60T13/58—Combined or convertible systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00—Parts or details
    • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
    • F16D65/28—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged apart from the brake
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2121/00—Type of actuator operation force
    • F16D2121/02—Fluid pressure
    • F16D2121/08—Fluid pressure acting on a membrane-type actuator, e.g. for gas pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2125/00—Components of actuators
    • F16D2125/02—Fluid-pressure mechanisms
    • F16D2125/12—Membrane or diaphragm types
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2125/00—Components of actuators
    • F16D2125/18—Mechanical mechanisms
    • F16D2125/58—Mechanical mechanisms transmitting linear movement
    • F16D2125/70—Rods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2127/00—Auxiliary mechanisms
    • F16D2127/06—Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms

Definitions

  • This invention relates to a braking system for a vehicle.
  • the invention relates to a braking system that enables application and release of a parking brake with fluid control and that also maintains appl ication of the brake during a loss of fluid pressure— all without using spring applied braking and using only a single fluid control conduit.
  • Conventional commercial vehicle braking systems typically include spring- actuated/fluid released parking brake actuators in which a mechanical spring actuates or applies the parkmg brake and pressurized fluid (typically pneumatic fluid) is used to release the brake.
  • the parking brake remains released as long as fluid pressure is maintained in the parking brake actuator.
  • the braking system typically has a common source of fluid pressure connected to actuators disposed at each wheel end of the of vehicle such that fluid pressure in a common control line simultaneously releases the parking brake for each wheel.
  • movement of the vehicle may be required because the immobilized vehicle is in a dangerous location (e.g., with high traffic volumes), is blocking the passage of other vehicles including potential emergency service vehicles, or is in a remote location far from potential repair facilities (e.g., a logging vehicle in a remote forest).
  • the spring in the actuator is relatively heavy, highly stressed to produce the parking force and also tends to corrode and fatigue over time. The corrosion makes repair and replacement different. More importantly, because of the significant spring forces applied in the actuator, unexpected failure of the spring may resul t in significant injury to maintenance and other personnel. Finally, constant fluid pressure is required to maintain the parking brake in a release position.
  • This invention relates to a braking system for a vehicle.
  • the invention relates to a braking system that enables application and release of a parking brake with fluid control and that also maintains application of the brake during a loss of fluid pressure al l without using spring applied brakmg and using only a single fluid control conduit.
  • a braking system in accordance with one embodiment of the present invention includes a brake actuator and a fluid control system.
  • the brake actuator includes a housing defining a sendee brake chamber and a parking brake chamber.
  • the brake actuator further includes a service diaphragm disposed within the service brake chamber and a service pushrod disposed on a first side of the service diaphragm. Introduction of fluid on a second side of the service diaphragm urges the service pushrod away from a service release position towards a service apply position.
  • the brake actuator further includes a parking diaphragm disposed within the parking brake chamber and having a first side facing the service diaphragm.
  • the fluid control system includes a relay valve comprising a delivery port in fluid communication with the parking brake chamber of the brake actuator and first and second control ports.
  • the fluid control system further includes a first inversion valve comprising a delivery port in fluid communication with the first control port of the relay valve, a supply port in fluid communication with a fluid control conduit, and a control port in fluid communication with the fluid control conduit.
  • the fluid control system further includes a second inversion valve comprising a delivery port in fluid communication with the second control port of the relay valve, a supply port, and a control port.
  • the fluid control system further includes a third inversion valve comprising a delivery port in fluid communication with the supply port of the second inversion valve and the control port of the second inversion valve, a supply port in fluid communication with a fluid source and a control port in fluid communication with the fluid control conduit.
  • a decrease in fluid pressure in the fluid control conduit enables delivery of fluid from the fluid source to the parking brake chamber and an increase in fluid pressure in the fluid control conduit enables exhaustion of fluid from the parking brake chamber.
  • a brake actuator for use in braking system in accordance with one embodiment of the present invention includes a housing defining a service brake chamber and a parking brake chamber.
  • the actuator further includes a service diaphragm disposed within the service brake chamber and a sendee pushrod di sposed on a first side of the service diaphragm.
  • the actuator further includes a parking diaphragm disposed within the parking brake chamber and a parking pushrod extending through the parking diaphragm.
  • the parking pushrod has a first end disposed on a first side of the parking diaphragm and extending into the service brake chamber and disposed on a second side of the sendee diaphragm.
  • the parking pushrod also defines a plurality of teeth.
  • the actuator further includes a spring disposed within the sendee brake chamber on the first side of the service diaphragm.
  • the spring biases the sendee pushrod to a service release position and the parking pushrod to a parking release position.
  • the actuator further includes a clutch disposed about the parking pushrod and defining a clutch tooth on a radially inner surface and configured for intermittent engagement with the plurality of teeth of the parking pushrod and a clutch actuator configured to control rotation of the clutch.
  • Introduction of fluid on the second side of the sendee diaphragm urges the sendee pushrod away from the service release position towards a service apply position.
  • Introduction of fluid on a second side of the parking diaphragm urges the parking pushrod away from the parking release position towards a parking apply position and the service pushrod away from the service release position towards the service apply position.
  • a brake actuator for use in braking system in accordance with another embodiment of the present invention includes a housing defining a service brake chamber and a parking brake chamber.
  • the actuator further includes a service diaphragm disposed within the sendee brake chamber and a service pushrod disposed on a first side of the service diaphragm.
  • the actuator further includes a parking diaphragm disposed within the parking brake chamber and a parking pushrod extending through the parking diaphragm.
  • the parking pushrod has a first end disposed on a first side of the parking diaphragm and extending into the serv ice brake chamber and disposed on a second side of the service diaphragm.
  • the actuator further includes a spring disposed within the service brake chamber on the first side of the service diaphragm.
  • the spring biases the sendee pushrod to a sendee release position and the parking pushrod to a parking release position.
  • the actuator further includes means for holding the parking pushrod in a parking apply position, introduction of fluid on the second side of the sendee diaphragm urges the sendee pushrod away from the service release position towards a sendee apply position.
  • Introduction of fluid on a second side of the parking diaphragm urges the parking pushrod away from the parking release position towards the parking apply position and the sendee pushrod away from the sendee release position towards the service apply position.
  • a fluid control system for a brake actuator for use in braking system in accordance with one embodiment of the present invention includes a relay valve comprising a delivery port, in fluid communication with a parking brake chamber of the brake actuator and first and second control ports.
  • the fluid control system further includes a first inversion valve comprising a delivery port in fluid communication with the first control port of the rel ay valve, a supply port in fluid
  • the fluid control system further includes a second inversion valve comprising a delivery port in fluid communication with the second control port of the relay valve, a supply port and a control port.
  • the fluid control system further includes a third inversion valve comprising a delivery port in fluid communication with the supply port of the second inversion valve and the control port of the second inversion valve, a supply port in fluid communication with a fluid source; and, a control port in fluid communication with the fluid control conduit.
  • a decrease in fluid pressure in the fluid control conduit enables delivery of fluid from the fluid source to the parking brake chamber.
  • An increase in fluid pressure in the fluid control conduit enables exhaustion of fluid from the parking brake chamber.
  • a braking system in accordance with the present invention represents an improvement relative to conventional braking systems.
  • the inventive braking system enables application of the parking brake using fluid control and can also maintain application of the brake during a loss of fluid pressure without using mechanical springs.
  • the weight of the actuator is reduced, repair and replacement of the parking brake actuator is easier and safer than conventional spring- actuated parking brake actuators, and a constant fluid pressure is not required to maintain the actuator in a released state.
  • the inventive braking system also permits selective release of the parking brake despite a leak or rupture in the fluid control system of the type that would result in actuation and locking of spring-actuated parking brake actuators.
  • the inventive braking system also achieves the above benefits while using a conventional two-line fluid control system (i.e., one fluid control line to the service brake chamber and another fluid control line to the parking brake chamber)— unlike conventional fluid-actuated parking brake actuators that require a separate fluid control line to maintain the position of the parking brake actuator.
  • Figure 1 is a diagrammatic view of a braking system in accordance with one
  • Figure 2 is a cross-sectional view of one embodiment of a brake actuator fur use in the braking system of Figure 1.
  • Figure 3 is a cross-sectional view of a portion of the brake actuator of Figure 2 taken along lines 3-3 in Figure 2.
  • Figure 4 is a cross-sectional view of a portion of the brake actuator of Figure 2 taken alones 4-4 in Figure 3.
  • Figure 1 illustrates a braking system 10 in accordance with one embodiment of the present invention.
  • System 10 is provided to control actuation and release of foundation brakes (not shown) applied to one or more vehicle wheels 12.
  • the brakes may comprise, for example, conventional drum brakes in which one or more brakes shoes are configured to engage and disengage a braking surface in a drum upon actuation and release of the brakes.
  • system 10 may include a fluid control system 14 and one or more brake actuators 16.
  • System 10 is configured for use with commercial vehicles including tracks and buses. It should be understood, however, that system 10 can be configured for use with a variety of vehicles.
  • Fluid control system 14 is provided to control distribution of fluid within system 10 and delivery of fluid to and venting of fluid from actuators 16.
  • Fluid control system 14 may include a fluid source 18 and one or more control valves 20, 22, 24, 26, 28, 30, 32 controlling distribution of fluid through system 10.
  • Fluid source 18 is conventional in the art any may comprise a fluid reservoir or tank for storing pressurized fluid.
  • a compressor (not shown) operated by the vehicle engine may be used for charging the tank with fluid pressure and one or more check valves (not shown) may be used to prevent loss of pressure from the tank in the event of an upstream or downstream pressure loss, in the illustrated embodiment the fluid comprises pneumatic fluid.
  • Fluid source 18 is coupled to one end of a conduit 34 extending between fluid source 18 and valve 32 and at one end of a conduit 38 extending between fluid source 18 and valve 28.
  • Valve 20 comprises a conventional foot control pedal valve for use in actuating and releasing the service brake.
  • the valve 20 opens to allow pressurized fluid to fiow r from a fluid source (not shown) through valve 20 to a control port on relay valve 30.
  • the increase in fluid pressure at the control port on valve 30 causes fluid pressure to flow from a fluid source (not shown ) through supply and delivery ports on valve 30 to actuator 16 in order the actuate the sendee brake.
  • valves 20 and 30 close and fluid pressure is exhausted to release the service brake.
  • Valve 20 is coupled at one end of conduit 40 extending between valve 20 and valve 30.
  • Valve 22 comprises a control valve for use in actuating and releasing the parking brake.
  • Valve 22 may be mounted on the dashboard in a truck cab and may comprise a manually operable push-pull button valve.
  • Vaive 22 may include a supply port through which fluid enters vaive 22 and a delivery port through which fluid exits vaive 22.
  • Valve 22 is coupled at one end of conduit 42 extending between valve 22 and valves 24, 28. Manually pulling the button on valve 22 exhausts fluid from conduit 42 to actuate the parking brake as described in greater detail below. Manually pressing the button causes delivery of fluid pressure from a fluid source (not shown) through valve 22 and conduit 42 to release the parking brake as described in greater detail below.
  • Valves 24, 26, 28, comprise inversion valves (i.e. valves that deliver fluid pressure in the absence of fluid pressure at a control port of the vaive).
  • V alves 24, 26, 28, may comprise the inversion valve offered for sale under the trademark "TR-3" by the applicant Bendix Commercial Vehicle Systems LLC.
  • Valves 24, 26, 28 each include a supply port S, a delivery port D, a control port C and an exhaust port. In valves 24, 26, however, control port C is plugged and an internal passage connects the supply port S and control port C.
  • the supply port S of valve 24 is coupled to one end of fluid conduit 42 extending between valve 22 and vaive 24 while the deliver ⁇ ' port D of valve 24 is coupled to one end of a fluid conduit 44 extending between valve 24 and valve 32.
  • the supply port 8 of valve 26 is coupled to one end of a conduit 46 extending between valve 26 and the delivery port D of valve 28 while the delivery port D of valve 26 is coupled to one end of a conduit 48 extending between valve 26 and valve 32.
  • the supply port S of valve 28 is coupled to one end of conduit 38 extending between fluid source 18 and valve 28.
  • the delivery port D of valve 28 is coupled to one end of a conduit 46 extending between valve 28 and the supply port S of valve 26.
  • the control port C of valve 28 is coupled to one end of the conduit 42 extending between control valve 22 and valve 28.
  • Valves 30, 32 comprise relay valves. Valves 30, 32 are provided to increase the speed of application and release of the brakes and are conventional in the art. Valves 30, 32 may comprise the relay valve offered for sale under the trademark "R-12DC" by the applicant Bendix Commercial Vehicle Systems LLC. Valve 30 has a supply port coupled to a service brake fluid source (not shown), and a delivery port coupled to one end of a conduit 50 extending between valve 30 and a service port 52 on actuator 16. Valve 30 also has a control port coupled to one end of conduit 40 extending between valve 20 and valve 30.
  • Valve 32 has a supply port coupled to one end of conduit 34 extending between fluid source 18 and valve 32 and a delivery port coupled to one end of a conduit 54 extending between valve 32 and a parking port 56 on actuator 16.
  • Valve 32 also has one control port coupled to one end of conduit 44 extending between valve 24 and valve 32 and another control port coupled to one end of conduit 48 extending between valve 26 and valve 32.
  • the fluid control system 14 of system 10 is configured to control actuation of the brakes associated with the wheels of a tractor in a tractor-trailer vehicle. It should be understood, however, that system 10 can be substantial ly replicated for use in controlling actuation of the brakes associated with the wheels of the trailer.
  • a trailer may have a fluid source 18, valves 24, 26, 28, 30, 32 and associated fluid conduits arranged substantially similar to the arrangement on the tractor and fluid conduits extending from control valves 20, 22 can be coupled to corresponding conduits on the trailer through a conventional glad hand connection.
  • actuator 16 is provided to control actuation and release of the brakes associated with the vehicle wheels 12.
  • Actuator 16 may include a housing 58, a service diaphragm 60, a service pushrod 62 movable between a service release position (shown in Figure 2) and sendee apply position, a spring 64, a parking diaphragm 66, a parking pushrod 68 movable between a parking release position (shown in Figure 2) and a parking apply position, means for holding the parking pushrod 68 in the parking apply position such as clutch 70 and means, such as clutch actuator 72, for rotating clutch 70.
  • Housing 58 provides structural support for the other components of actuator 16 and protects those components from foreign objects and elements. Housing 58 further defines a service brake chamber 74 and a parking brake chamber 76. Housing 58 may include multiple housing members 78, 80, 82, 84. Members 78, 80 define service brake chamber 74 and receive service diaphragm 60 therebetween. Members 78, 80, may be held in place by a conventional clamp 86 disposed about the circumference of housing 58. Members 78, 80 defines aligned central apertures through which service pushrod 62. Member 78 also defines surrounding apertures through which mounting bolts 88 may extend for mounting actuator 16 within the vehicle. Conventional nuts and washers may be disposed about bolts 88 to securely fasten actuator 16 to the vehicle.
  • Members 80, 82 define parking brake chamber 76 and receive parking diaphragm 66 therebetween. Members 80, 82 may be held in place by crimping one or both of members 80, 82 or through the use of a cl amp as described above or other conventional fasteners. Members 80, 82 define aligned central apertures through which parking pushrod 68 may extend. Members 82, 84 further defines a chamber 90 configured to receive clutch 70 and clutch actuator 72.
  • Service diaphragm 60 is provided to urge sendee pushrod 62 outward from actuator 16 in response to fluid pressure in order to cause application of the vehicle brakes.
  • Diaphragm 60 is conventional in the art. Diaphragm 60 is disposed within chamber 74 and may be held between members 78, 80 of housing 58. Fluid pressure may be introduced to sendee chamber 74 on one side of diaphragm 60 opposite the side on which sendee pushrod 62 is disposed through sendee port 52 via fluid conduit 50 (see Figure 1 ). Introduction of fluid pressure to chamber 74 urges service pushrod 62 to a sendee apply position.
  • Service pushrod 62 transfers forces generated in actuator 16 to the vehicle brakes in order to apply or release the brakes.
  • Pushrod 62 is disposed about and moves along a longitudinal axis 92.
  • Pushrod 62 may define a yoke 94 at one end of the pushrod 62 disposed outside of housing 58.
  • the yoke 94 may be coupled to a slack adjuster (not shown) that is disposed about a camshaft (not shown) and translates linear movement of the service pushrod 62 into rotational movement of the camshaft and a cam (not shown) mounted on one end of the camshaft.
  • Pushrod 62 may define a pressure plate 96 at an opposite end from yoke 94.
  • Plate 96 provides a surface on one side configured to engage diaphragm 60 and a surface on the opposite side configured to act as a spring seat for spring 64.
  • Spring 64 is provided to bias service pushrod 62 to a service release position and parking pushrod 68 to a parking release position.
  • Spring 64 is conventional in the art and is disposed within sendee brake chamber 74 on one side of service diaphragm 60.
  • Spring 64 is disposed about service pushrod 62 and is seated between member 78 of housing 58 and pressure plate 94 of pushrod 62.
  • Parking diaphragm 66 is provided to urge parking pushrod 68 in one direction along axis 92 away from the parking release position and towards the parking apply position in response to fluid pressure in order to cause application of the vehicle brakes.
  • Diaphragm 66 is conventional in the art.
  • Diaphragm 66 is disposed within chamber 76 and may be held between members 80, 82 of housing 58. Fluid pressure may be introduced to parking brake chamber 76 on one side of diaphragm 66 through a parking port 56 via fluid conduit 54 (see Figure 1 ). Introduction of fluid pressure urges parking pushrod 68 to a parking apply position.
  • Parking pushrod 68 is provided to cause movement of sendee diaphragm 60 and service pushrod 62 in response to the introduction of fluid pressure in parking brake chamber 76 in order to apply or release the brakes.
  • Pushrod 68 is disposed about and moves along axis 92 and may be axially aligned with pushrod 62.
  • Pushrod 68 extends through parking diaphragm 66 and is configured for movement with parking diaphragm 66.
  • Pushrod 68 may comprise multiple members
  • Member 98 of pushrod 68 is disposed on one side of diaphragm 66 and extends into service brake chamber 74.
  • Member 98 defines a pressure plate 102 at one longitudinal end of pushrod 68 configured for selective engagement with one side of sendee diaphragm 60.
  • Pushrod 68 further defines another pressure plate 104 intermediate the longitudinal ends of pushrod 68. Plate 104 is disposed on one side of parking diaphragm 66.
  • member 100 of parking pushrod 68 may define a plurality of teeth 106 for a purpose described below. Referring to Figures 2-4, in one
  • two sets of teeth 106 may be arranged in separate longitudinally extending rows on pushrod 68. Each row of teeth 106 extends over only a circumferential portion of the outer circumferential surface of the pushrod 68, Referring to Figure 3, the two rows of teeth 106 may be diametrically opposite one another and the circumferential portions of the outer circumferential surface of pushrod 68 between the rows of teeth 106 may be un toothed or smooth.
  • Clutch 70 is provided to hold parking pushrod 68 in the parking apply position.
  • clutch 70 is annular in construction and is disposed within chamber 90 about pushrod 68.
  • Clutch 70 is a one-way or ratchet clutch.
  • clutch 70 defines at least one or more clutch teeth 108 on a radially inner surface of the clutch 70.
  • Teeth 108 may formed in an axially extending row along the radially inner surface of clutch 70.
  • Teeth 108 may also be formed on a pawl 1 10 that is disposed in a recess in the radially inner surface of clutch 70 and that is biased radially inwardly towards pushrod 68 by one or more springs 112.
  • clutch teeth 108 have a profile such that, during alignment of clutch teeth 108 and teeth 106 on parking pushrod 68, movement of parking pushrod 68 is permitted in one direction along axis 92 away from the parking release position and towards the parking apply position (i.e. downward in Figure 2) and movement of the parking pushrod 68 is inhibited in an opposite direction along axis 92 away from parking apply position and towards the parking release position (i.e. upward in Figure 2).
  • fluid pressure introduced into parking brake chamber 76 will result in movement of pushrod 68 to the parking apply position and, thereafter, clutch 70 will prevent release of the parking brake (until directed as discussed below) even in the event of a loss of fluid pressure in parking brake chamber 76.
  • clutch 70 also defines a plurality of ratchet teeth 1 14 on a radially outer surface of clutch 70. In the illustrated embodiment clutch 70 defines four ratchet teeth that are equally
  • Ratchet teeth 70 have a profile defining a relatively gradual slope on one side and a relatively steep slope on another side for a purpose discussed hereinbelow.
  • Clutch actuator 72 is provided to control rotation of clutch 70 about pushrod 68.
  • clutch 70 is rotated in ninety degree increments such that the teeth 108 on clutch 70 are moved into and out of engagement with rows of teeth 106 on pushrod 68.
  • the next rotation of clutch 70 disengages teeth 108 from teeth 106 on pushrod 68 and allows pushrod 68 to move to the parking release position under the force of spring 64 in service chamber 74.
  • Actuator 72 may include a piston 116, a pawl 118 and a spring 120,
  • One end of piston 1 16 is disposed within a fluid chamber 122 formed in housing 58.
  • Piston 116 defines mounting surfaces for pawl 1 18 and spring 120.
  • Pawl 118 transfers force from movement of piston 116 to clutch 70 in order to cause rotation of clutch 70.
  • Pawl 1 18 has one end pivotally mounted on piston 1 16. The opposite, or free, end of pawl 118 is biased away from piston 1 16 by spring 120 and is configured to engage one of ratchet teeth 1 14 on clutch 70 and, in particular, the side of a tooth 1 14 having a relatively steep slope. Movement of piston 1 16 in response to fluid pressure is transferred to clutch 70 through the engagement of pawl 118 with a corresponding ratchet tooth 1 14 of clutch 70.
  • the illustrated clutch 70 rotates ninety degrees in order to align clutch teeth 108 on clutch 70 with either teeth 106 on pushrod 68 (when the parking brake is applied) or an untoothed portion of pushrod 68 (when the par king brake is released).
  • a spring (not shown) returns piston 116 to its original position and pawl 118 slides over the next ratchet tooth 104— in particular, the side of the tooth 104 having a relatively gradual slope— -to reposition paw 1 18 for the next desired rotation of clutch 70.
  • Fluid pressure in chamber 76 parking pushrod 68 to the parking apply position and, consequently, service pushrod 62 to the sendee apply position against the force of spring 64 in order to apply the vehicle brakes. Fluid is also delivered through conduit 54 to fluid chamber 122 resulting in rotation of clutch 70 such that the clutch teeth 108 on clutch 70 are aligned with teeth 106 on pushrod 68. As a result, while pushrod 68 is able to move to the parking apply position freely, pushrod 68 is temporarily prevented from returning to the parking release position. Once the fluid pressure in chamber 76 reaches a predetermined level, valve 26 closes and the remaining fluid pressure in conduits 48, 54 is exhausted. Pressure is also vented from parking brake chamber 76.
  • clutch 70 retains the position of parking pushrod 68, constant fluid pressure is not required for continued application of the parking brake. Further, the inventive braking system allows variation in the applied parking brake force without varying the size of the parking brake chamber. Rather, valve 26 can be adjusted to control the predetermined pressure at which further delivery of fluid is stopped.
  • valve 24 When the vehicle operator wants to release the parking brake, the operator pushes in the control button on control valve 22 which increases fluid pressure in conduit 42. Because valve 24 is open (due to the prior absence of fluid pressure in conduit 42), fluid from conduit 42 initially flows through supply port S on valve 24 to delivery port D on valve 24 and into conduit 44. Fluid flow into conduit 44 occurs until a predetermined fluid pressure is reached and valve 24 closes and exhausts to atmosphere. Fluid in conduit 44 is delivered to a control port of valve 32. This action causes delivery of fluid from fluid source 20 through valve 32 and conduit 54 to parking port 56 and into parking brake chamber 76 of actuator 16 and also into fluid chamber 122 thereby causing rotation of clutch 70 such that clutch teeth 108 on clutch 70 are no longer aligned with the teeth 106 on pushrod 68. Once the predetermined pressure is reached, valves 24, 32 close and conduits 44, 54
  • a braking system 10 in accordance with the present invention represents an
  • the inventive braking system 10 enables application of the parking brake using fluid control rather than mechanical springs and can also maintain application of the parking brake during a loss of fluid pressure. As a result, the weight of the actuator is reduced, repair and replacement of the parking brake actuator is easier and safer than conventional spring-actuated parking brake actuators, and a constant fluid pressure is not required to maintain the actuator in a released state.
  • a diaphragm is more durable than a parking spring which equates to longer life.
  • the inventive braking system also permits selective release of the parking brake despite a leak or rupture in the fluid control system of the type that would result in actuation and locking of spring-actuated parking brake actuators.
  • the inventive braking system also achieves the above benefits while using a conventional two-line fluid control system (i.e., one fluid control line to the service brake chamber and another fluid control line to the parking brake chamber)— unlike conventional fluid-actuated parking brake actuators that require a separate fluid control line to maintain the position of the parking brake actuator.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Braking Arrangements (AREA)
  • Braking Systems And Boosters (AREA)

Abstract

A braking system is provided that enables application and release of a parking brake with fluid control and that also maintains application of the brake during a loss of fluid pressure—all without using springs and using only a single fluid control conduit. The brake actuator for the system includes a housing defining service and parking chambers. A pushrod in the parking chamber is configured for movement with a diaphragm in the chamber. The parking brake is applied by introducing fluid on one side of the diaphragm. A clutch surrounds the pushrod and includes a tooth configured to engage corresponding teeth on the pushrod to hold the position of the pushrod even during a loss of fluid pressure. The clutch is rotated under fluid control to move the clutch tooth into and out of alignment with the teeth on the pushrod to hold and release the parking brake.

Description

BRAKING SYSTEM WITH NON-SPRING PARKING BRAKE ACTUATOR
BACKGROUND OF THE INVENTION
a. Field of the Invention
[0001] This invention relates to a braking system for a vehicle. In particular, the invention relates to a braking system that enables application and release of a parking brake with fluid control and that also maintains appl ication of the brake during a loss of fluid pressure— all without using spring applied braking and using only a single fluid control conduit. b. Background Art.
[0002] Conventional commercial vehicle braking systems typically include spring- actuated/fluid released parking brake actuators in which a mechanical spring actuates or applies the parkmg brake and pressurized fluid (typically pneumatic fluid) is used to release the brake. The parking brake remains released as long as fluid pressure is maintained in the parking brake actuator. The braking system typically has a common source of fluid pressure connected to actuators disposed at each wheel end of the of vehicle such that fluid pressure in a common control line simultaneously releases the parking brake for each wheel.
[0003] The use of spring-actuated/fluid released parking brake actuators has several drawbacks. An unintended loss of fluid pressure due to, for example, a leak or rupture in the fluid control system results in actuation of the parking brakes on each wheel. While this action is desirable-and even required in certain circumstances-to meet safety concerns, the action is undesirable in many other circumstances. For example, in military applications it is not uncommon for the fluid control system to become damaged as a result of damage to a single wheel from an improvised explosive device (IED). Actuation of the parking brakes in this circumstance immobilizes the vehicle and may trap the vehicle occupants in a hostile environment. In other applications, movement of the vehicle may be required because the immobilized vehicle is in a dangerous location (e.g., with high traffic volumes), is blocking the passage of other vehicles including potential emergency service vehicles, or is in a remote location far from potential repair facilities (e.g., a logging vehicle in a remote forest). The spring in the actuator is relatively heavy, highly stressed to produce the parking force and also tends to corrode and fatigue over time. The corrosion makes repair and replacement different. More importantly, because of the significant spring forces applied in the actuator, unexpected failure of the spring may resul t in significant injury to maintenance and other personnel. Finally, constant fluid pressure is required to maintain the parking brake in a release position.
[0004] in order to overcome some of the problems associated with sprmg-aetuated/fluid released parking brake actuators, some actuators have been developed that use fluid pressure to actuate the parking brake. One example is the brake actuator previously offered for sale under the trademark DD-3 by the applicant Bendix Commercial Vehicle Systems LLC. For proper functioning of the parking brake, fluid actuated parking brake actuators must include means to maintain application of the parking brake despite any loss in fluid pressure. In the case of the DD-3 and similar brake actuators, a separate fluid control line has been used to actuate the locking mechanism. The requirement for an additional fluid control line, however, increases the number of parts, cost, and complexity of the braking system .
[0005] The inventors herein have recognized a need for a braking system that will minimize and/or eliminate one or more of the above-identified deficiencies.
BRIEF SUMMARY OF THE INVENTION
[0006] This invention relates to a braking system for a vehicle. In particular, the invention relates to a braking system that enables application and release of a parking brake with fluid control and that also maintains application of the brake during a loss of fluid pressure al l without using spring applied brakmg and using only a single fluid control conduit.
[0007J A braking system in accordance with one embodiment of the present invention includes a brake actuator and a fluid control system. The brake actuator includes a housing defining a sendee brake chamber and a parking brake chamber. The brake actuator further includes a service diaphragm disposed within the service brake chamber and a service pushrod disposed on a first side of the service diaphragm. Introduction of fluid on a second side of the service diaphragm urges the service pushrod away from a service release position towards a service apply position. The brake actuator further includes a parking diaphragm disposed within the parking brake chamber and having a first side facing the service diaphragm. Introduction of fluid on a second side of the parking diaphragm urging the sendee pushrod to the sendee apply position. The fluid control system includes a relay valve comprising a delivery port in fluid communication with the parking brake chamber of the brake actuator and first and second control ports. The fluid control system further includes a first inversion valve comprising a delivery port in fluid communication with the first control port of the relay valve, a supply port in fluid communication with a fluid control conduit, and a control port in fluid communication with the fluid control conduit. The fluid control system further includes a second inversion valve comprising a delivery port in fluid communication with the second control port of the relay valve, a supply port, and a control port. The fluid control system further includes a third inversion valve comprising a delivery port in fluid communication with the supply port of the second inversion valve and the control port of the second inversion valve, a supply port in fluid communication with a fluid source and a control port in fluid communication with the fluid control conduit. A decrease in fluid pressure in the fluid control conduit enables delivery of fluid from the fluid source to the parking brake chamber and an increase in fluid pressure in the fluid control conduit enables exhaustion of fluid from the parking brake chamber.
[0ΘΘ8] A brake actuator for use in braking system in accordance with one embodiment of the present invention includes a housing defining a service brake chamber and a parking brake chamber. The actuator further includes a service diaphragm disposed within the service brake chamber and a sendee pushrod di sposed on a first side of the service diaphragm. The actuator further includes a parking diaphragm disposed within the parking brake chamber and a parking pushrod extending through the parking diaphragm. The parking pushrod has a first end disposed on a first side of the parking diaphragm and extending into the service brake chamber and disposed on a second side of the sendee diaphragm. The parking pushrod also defines a plurality of teeth. The actuator further includes a spring disposed within the sendee brake chamber on the first side of the service diaphragm. The spring biases the sendee pushrod to a service release position and the parking pushrod to a parking release position. The actuator further includes a clutch disposed about the parking pushrod and defining a clutch tooth on a radially inner surface and configured for intermittent engagement with the plurality of teeth of the parking pushrod and a clutch actuator configured to control rotation of the clutch. Introduction of fluid on the second side of the sendee diaphragm urges the sendee pushrod away from the service release position towards a service apply position. Introduction of fluid on a second side of the parking diaphragm urges the parking pushrod away from the parking release position towards a parking apply position and the service pushrod away from the service release position towards the service apply position.
[0009] A brake actuator for use in braking system in accordance with another embodiment of the present invention includes a housing defining a service brake chamber and a parking brake chamber. The actuator further includes a service diaphragm disposed within the sendee brake chamber and a service pushrod disposed on a first side of the service diaphragm. The actuator further includes a parking diaphragm disposed within the parking brake chamber and a parking pushrod extending through the parking diaphragm. The parking pushrod has a first end disposed on a first side of the parking diaphragm and extending into the serv ice brake chamber and disposed on a second side of the service diaphragm. The actuator further includes a spring disposed within the service brake chamber on the first side of the service diaphragm. The spring biases the sendee pushrod to a sendee release position and the parking pushrod to a parking release position. The actuator further includes means for holding the parking pushrod in a parking apply position, introduction of fluid on the second side of the sendee diaphragm urges the sendee pushrod away from the service release position towards a sendee apply position. Introduction of fluid on a second side of the parking diaphragm urges the parking pushrod away from the parking release position towards the parking apply position and the sendee pushrod away from the sendee release position towards the service apply position.
[0010] A fluid control system for a brake actuator for use in braking system in accordance with one embodiment of the present invention includes a relay valve comprising a delivery port, in fluid communication with a parking brake chamber of the brake actuator and first and second control ports. The fluid control system further includes a first inversion valve comprising a delivery port in fluid communication with the first control port of the rel ay valve, a supply port in fluid
communication with a fluid control conduit and a control port in fluid communication with the fluid control conduit. The fluid control system further includes a second inversion valve comprising a delivery port in fluid communication with the second control port of the relay valve, a supply port and a control port. The fluid control system further includes a third inversion valve comprising a delivery port in fluid communication with the supply port of the second inversion valve and the control port of the second inversion valve, a supply port in fluid communication with a fluid source; and, a control port in fluid communication with the fluid control conduit. A decrease in fluid pressure in the fluid control conduit enables delivery of fluid from the fluid source to the parking brake chamber. An increase in fluid pressure in the fluid control conduit enables exhaustion of fluid from the parking brake chamber.
[0011] A braking system in accordance with the present invention represents an improvement relative to conventional braking systems. The inventive braking system enables application of the parking brake using fluid control and can also maintain application of the brake during a loss of fluid pressure without using mechanical springs. As a result, the weight of the actuator is reduced, repair and replacement of the parking brake actuator is easier and safer than conventional spring- actuated parking brake actuators, and a constant fluid pressure is not required to maintain the actuator in a released state. The inventive braking system also permits selective release of the parking brake despite a leak or rupture in the fluid control system of the type that would result in actuation and locking of spring-actuated parking brake actuators. As a result, the vehicle is not immobilized and the vehicle and its occupants can be moved, if necessary, to a safer or more accessible location and/or out of the way of other vehicles. The inventive braking system also achieves the above benefits while using a conventional two-line fluid control system (i.e., one fluid control line to the service brake chamber and another fluid control line to the parking brake chamber)— unlike conventional fluid-actuated parking brake actuators that require a separate fluid control line to maintain the position of the parking brake actuator.
[0Θ12] The foregoing and other aspects, features, details, utilities, and advantages of the present invention will, be apparent from reading the following description and claims, and from reviewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 is a diagrammatic view of a braking system in accordance with one
embodiment of the present invention.
[0Θ14] Figure 2 is a cross-sectional view of one embodiment of a brake actuator fur use in the braking system of Figure 1.
[0015] Figure 3 is a cross-sectional view of a portion of the brake actuator of Figure 2 taken along lines 3-3 in Figure 2. [0Θ16] Figure 4 is a cross-sectional view of a portion of the brake actuator of Figure 2 taken alones 4-4 in Figure 3.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views, Figure 1 illustrates a braking system 10 in accordance with one embodiment of the present invention. System 10 is provided to control actuation and release of foundation brakes (not shown) applied to one or more vehicle wheels 12. The brakes may comprise, for example, conventional drum brakes in which one or more brakes shoes are configured to engage and disengage a braking surface in a drum upon actuation and release of the brakes. In addition to conventional vehicle brakes, system 10 may include a fluid control system 14 and one or more brake actuators 16. System 10 is configured for use with commercial vehicles including tracks and buses. It should be understood, however, that system 10 can be configured for use with a variety of vehicles.
[0018] Fluid control system 14 is provided to control distribution of fluid within system 10 and delivery of fluid to and venting of fluid from actuators 16. Fluid control system 14 may include a fluid source 18 and one or more control valves 20, 22, 24, 26, 28, 30, 32 controlling distribution of fluid through system 10.
[001 ] Fluid source 18 is conventional in the art any may comprise a fluid reservoir or tank for storing pressurized fluid. A compressor (not shown) operated by the vehicle engine may be used for charging the tank with fluid pressure and one or more check valves (not shown) may be used to prevent loss of pressure from the tank in the event of an upstream or downstream pressure loss, in the illustrated embodiment the fluid comprises pneumatic fluid. Fluid source 18 is coupled to one end of a conduit 34 extending between fluid source 18 and valve 32 and at one end of a conduit 38 extending between fluid source 18 and valve 28.
[0020] Valve 20 comprises a conventional foot control pedal valve for use in actuating and releasing the service brake. When the pedal is depressed, the valve 20 opens to allow pressurized fluid to fiowr from a fluid source (not shown) through valve 20 to a control port on relay valve 30. The increase in fluid pressure at the control port on valve 30 causes fluid pressure to flow from a fluid source (not shown ) through supply and delivery ports on valve 30 to actuator 16 in order the actuate the sendee brake. When the pedal is released, valves 20 and 30 close and fluid pressure is exhausted to release the service brake. Valve 20 is coupled at one end of conduit 40 extending between valve 20 and valve 30.
[0021] Valve 22 comprises a control valve for use in actuating and releasing the parking brake. Valve 22 may be mounted on the dashboard in a truck cab and may comprise a manually operable push-pull button valve. Vaive 22 may include a supply port through which fluid enters vaive 22 and a delivery port through which fluid exits vaive 22. Valve 22 is coupled at one end of conduit 42 extending between valve 22 and valves 24, 28. Manually pulling the button on valve 22 exhausts fluid from conduit 42 to actuate the parking brake as described in greater detail below. Manually pressing the button causes delivery of fluid pressure from a fluid source (not shown) through valve 22 and conduit 42 to release the parking brake as described in greater detail below.
[0022] Valves 24, 26, 28, comprise inversion valves (i.e. valves that deliver fluid pressure in the absence of fluid pressure at a control port of the vaive). V alves 24, 26, 28, may comprise the inversion valve offered for sale under the trademark "TR-3" by the applicant Bendix Commercial Vehicle Systems LLC. Valves 24, 26, 28 each include a supply port S, a delivery port D, a control port C and an exhaust port. In valves 24, 26, however, control port C is plugged and an internal passage connects the supply port S and control port C. The supply port S of valve 24 is coupled to one end of fluid conduit 42 extending between valve 22 and vaive 24 while the deliver}' port D of valve 24 is coupled to one end of a fluid conduit 44 extending between valve 24 and valve 32. The supply port 8 of valve 26 is coupled to one end of a conduit 46 extending between valve 26 and the delivery port D of valve 28 while the delivery port D of valve 26 is coupled to one end of a conduit 48 extending between valve 26 and valve 32. The supply port S of valve 28 is coupled to one end of conduit 38 extending between fluid source 18 and valve 28. The delivery port D of valve 28 is coupled to one end of a conduit 46 extending between valve 28 and the supply port S of valve 26. Finally, the control port C of valve 28 is coupled to one end of the conduit 42 extending between control valve 22 and valve 28.
[0023] Valves 30, 32 comprise relay valves. Valves 30, 32 are provided to increase the speed of application and release of the brakes and are conventional in the art. Valves 30, 32 may comprise the relay valve offered for sale under the trademark "R-12DC" by the applicant Bendix Commercial Vehicle Systems LLC. Valve 30 has a supply port coupled to a service brake fluid source (not shown), and a delivery port coupled to one end of a conduit 50 extending between valve 30 and a service port 52 on actuator 16. Valve 30 also has a control port coupled to one end of conduit 40 extending between valve 20 and valve 30. Valve 32 has a supply port coupled to one end of conduit 34 extending between fluid source 18 and valve 32 and a delivery port coupled to one end of a conduit 54 extending between valve 32 and a parking port 56 on actuator 16. Valve 32 also has one control port coupled to one end of conduit 44 extending between valve 24 and valve 32 and another control port coupled to one end of conduit 48 extending between valve 26 and valve 32.
[0024] As illustrated in Figure 1 , the fluid control system 14 of system 10 is configured to control actuation of the brakes associated with the wheels of a tractor in a tractor-trailer vehicle. It should be understood, however, that system 10 can be substantial ly replicated for use in controlling actuation of the brakes associated with the wheels of the trailer. In particular, a trailer may have a fluid source 18, valves 24, 26, 28, 30, 32 and associated fluid conduits arranged substantially similar to the arrangement on the tractor and fluid conduits extending from control valves 20, 22 can be coupled to corresponding conduits on the trailer through a conventional glad hand connection.
[0Θ25] Referring now to Figure 2, actuator 16 is provided to control actuation and release of the brakes associated with the vehicle wheels 12. Actuator 16 may include a housing 58, a service diaphragm 60, a service pushrod 62 movable between a service release position (shown in Figure 2) and sendee apply position, a spring 64, a parking diaphragm 66, a parking pushrod 68 movable between a parking release position (shown in Figure 2) and a parking apply position, means for holding the parking pushrod 68 in the parking apply position such as clutch 70 and means, such as clutch actuator 72, for rotating clutch 70.
[0Θ26] Housing 58 provides structural support for the other components of actuator 16 and protects those components from foreign objects and elements. Housing 58 further defines a service brake chamber 74 and a parking brake chamber 76. Housing 58 may include multiple housing members 78, 80, 82, 84. Members 78, 80 define service brake chamber 74 and receive service diaphragm 60 therebetween. Members 78, 80, may be held in place by a conventional clamp 86 disposed about the circumference of housing 58. Members 78, 80 defines aligned central apertures through which service pushrod 62. Member 78 also defines surrounding apertures through which mounting bolts 88 may extend for mounting actuator 16 within the vehicle. Conventional nuts and washers may be disposed about bolts 88 to securely fasten actuator 16 to the vehicle. Members 80, 82 define parking brake chamber 76 and receive parking diaphragm 66 therebetween. Members 80, 82 may be held in place by crimping one or both of members 80, 82 or through the use of a cl amp as described above or other conventional fasteners. Members 80, 82 define aligned central apertures through which parking pushrod 68 may extend. Members 82, 84 further defines a chamber 90 configured to receive clutch 70 and clutch actuator 72.
[0Θ27] Service diaphragm 60 is provided to urge sendee pushrod 62 outward from actuator 16 in response to fluid pressure in order to cause application of the vehicle brakes. Diaphragm 60 is conventional in the art. Diaphragm 60 is disposed within chamber 74 and may be held between members 78, 80 of housing 58. Fluid pressure may be introduced to sendee chamber 74 on one side of diaphragm 60 opposite the side on which sendee pushrod 62 is disposed through sendee port 52 via fluid conduit 50 (see Figure 1 ). Introduction of fluid pressure to chamber 74 urges service pushrod 62 to a sendee apply position.
[0Θ28] Service pushrod 62 transfers forces generated in actuator 16 to the vehicle brakes in order to apply or release the brakes. Pushrod 62 is disposed about and moves along a longitudinal axis 92. Pushrod 62 may define a yoke 94 at one end of the pushrod 62 disposed outside of housing 58. In a conventional drum brake, for example, the yoke 94 may be coupled to a slack adjuster (not shown) that is disposed about a camshaft (not shown) and translates linear movement of the service pushrod 62 into rotational movement of the camshaft and a cam (not shown) mounted on one end of the camshaft. Rotation of the cam then causes corresponding movement of brakes shoes into and out of engagement with a braking surface in a drum. Pushrod 62 may define a pressure plate 96 at an opposite end from yoke 94. Plate 96 provides a surface on one side configured to engage diaphragm 60 and a surface on the opposite side configured to act as a spring seat for spring 64.
[0029] Spring 64 is provided to bias service pushrod 62 to a service release position and parking pushrod 68 to a parking release position. Spring 64 is conventional in the art and is disposed within sendee brake chamber 74 on one side of service diaphragm 60. Spring 64 is disposed about service pushrod 62 and is seated between member 78 of housing 58 and pressure plate 94 of pushrod 62. [0Θ30] Parking diaphragm 66 is provided to urge parking pushrod 68 in one direction along axis 92 away from the parking release position and towards the parking apply position in response to fluid pressure in order to cause application of the vehicle brakes. Diaphragm 66 is conventional in the art. Diaphragm 66 is disposed within chamber 76 and may be held between members 80, 82 of housing 58. Fluid pressure may be introduced to parking brake chamber 76 on one side of diaphragm 66 through a parking port 56 via fluid conduit 54 (see Figure 1 ). Introduction of fluid pressure urges parking pushrod 68 to a parking apply position.
[0Θ31] Parking pushrod 68 is provided to cause movement of sendee diaphragm 60 and service pushrod 62 in response to the introduction of fluid pressure in parking brake chamber 76 in order to apply or release the brakes. Pushrod 68 is disposed about and moves along axis 92 and may be axially aligned with pushrod 62. Pushrod 68 extends through parking diaphragm 66 and is configured for movement with parking diaphragm 66. Pushrod 68 may comprise multiple members
98, 100 generally disposed on opposite sides of diaphragm 66. Member 98 of pushrod 68 is disposed on one side of diaphragm 66 and extends into service brake chamber 74. Member 98 defines a pressure plate 102 at one longitudinal end of pushrod 68 configured for selective engagement with one side of sendee diaphragm 60. Pushrod 68 further defines another pressure plate 104 intermediate the longitudinal ends of pushrod 68. Plate 104 is disposed on one side of parking diaphragm 66. Introduction of fluid pressure on the opposite side of diaphragm 66 urges pushrod 68 to a parking apply position and therefore urges service pushrod 62 to the service apply position via the force exerted on service diaphragm 60 by pl ate 102 of parking pushrod 68. In accordance with one aspect of the present invention, member 100 of parking pushrod 68 may define a plurality of teeth 106 for a purpose described below. Referring to Figures 2-4, in one
embodiment, two sets of teeth 106 may be arranged in separate longitudinally extending rows on pushrod 68. Each row of teeth 106 extends over only a circumferential portion of the outer circumferential surface of the pushrod 68, Referring to Figure 3, the two rows of teeth 106 may be diametrically opposite one another and the circumferential portions of the outer circumferential surface of pushrod 68 between the rows of teeth 106 may be un toothed or smooth.
[0032] Clutch 70 is provided to hold parking pushrod 68 in the parking apply position. Clutch
70 is annular in construction and is disposed within chamber 90 about pushrod 68. Clutch 70 is a one-way or ratchet clutch. Referring to Figures 3-4, clutch 70 defines at least one or more clutch teeth 108 on a radially inner surface of the clutch 70. Teeth 108 may formed in an axially extending row along the radially inner surface of clutch 70. Teeth 108 may also be formed on a pawl 1 10 that is disposed in a recess in the radially inner surface of clutch 70 and that is biased radially inwardly towards pushrod 68 by one or more springs 112. The clutch teeth 108 have a profile such that, during alignment of clutch teeth 108 and teeth 106 on parking pushrod 68, movement of parking pushrod 68 is permitted in one direction along axis 92 away from the parking release position and towards the parking apply position (i.e. downward in Figure 2) and movement of the parking pushrod 68 is inhibited in an opposite direction along axis 92 away from parking apply position and towards the parking release position (i.e. upward in Figure 2). As a result, fluid pressure introduced into parking brake chamber 76 will result in movement of pushrod 68 to the parking apply position and, thereafter, clutch 70 will prevent release of the parking brake (until directed as discussed below) even in the event of a loss of fluid pressure in parking brake chamber 76. Referring to Figure 3, clutch 70 also defines a plurality of ratchet teeth 1 14 on a radially outer surface of clutch 70. In the illustrated embodiment clutch 70 defines four ratchet teeth that are equally
circumferentiaily spaced about clutch 70 (i.e. every ninety degrees). Ratchet teeth 70 have a profile defining a relatively gradual slope on one side and a relatively steep slope on another side for a purpose discussed hereinbelow.
[0033] Clutch actuator 72 is provided to control rotation of clutch 70 about pushrod 68. In accordance with one embodiment of the invention, clutch 70 is rotated in ninety degree increments such that the teeth 108 on clutch 70 are moved into and out of engagement with rows of teeth 106 on pushrod 68. As a result, when pushrod 68 is in the parking apply position, the next rotation of clutch 70 disengages teeth 108 from teeth 106 on pushrod 68 and allows pushrod 68 to move to the parking release position under the force of spring 64 in service chamber 74. The next rotation of clutch 70 would then occur during actuation of the parking brake (as discussed below) and cause reengagement of teeth 108 with another row of teeth 106 on pushrod 68 to hold pushrod 68 in the parking apply position. Actuator 72 may include a piston 116, a pawl 118 and a spring 120,
[0034] One end of piston 1 16 is disposed within a fluid chamber 122 formed in housing 58.
Fluid pressure within chamber 122 urges piston 120 in one direction (upward in Figure 3). A spring
(not shown) may bias piston 120 in the opposite direction (downward in Figure 3). Piston 116 defines mounting surfaces for pawl 1 18 and spring 120.
I I [0Θ35] Pawl 118 transfers force from movement of piston 116 to clutch 70 in order to cause rotation of clutch 70. Pawl 1 18 has one end pivotally mounted on piston 1 16. The opposite, or free, end of pawl 118 is biased away from piston 1 16 by spring 120 and is configured to engage one of ratchet teeth 1 14 on clutch 70 and, in particular, the side of a tooth 1 14 having a relatively steep slope. Movement of piston 1 16 in response to fluid pressure is transferred to clutch 70 through the engagement of pawl 118 with a corresponding ratchet tooth 1 14 of clutch 70. Because of the profile of ratchet teeth 114, the illustrated clutch 70 rotates ninety degrees in order to align clutch teeth 108 on clutch 70 with either teeth 106 on pushrod 68 (when the parking brake is applied) or an untoothed portion of pushrod 68 (when the par king brake is released). Once fluid pressure in chamber 112 is removed, a spring (not shown) returns piston 116 to its original position and pawl 118 slides over the next ratchet tooth 104— in particular, the side of the tooth 104 having a relatively gradual slope— -to reposition paw 1 18 for the next desired rotation of clutch 70.
[0036] Referring to Figures 1 -2, the operation of braking system 10 will, now be described in greater detail. Actuation of the service brake is accomplished by depressing foot pedal valve 20. This action causes relay valve 30 to direct fluid from a fluid source (not shown) to service port 52 of actuator 16 and into service brake chamber 74 on one side of diaphragm 60. Fluid pressure in chamber 74 urges diaphragm 60 and sendee pushrod 62 to a service apply position against the force of spring 64 to apply the vehicle brakes. When the pedal is released, valve 20 closes and fluid pressure is exhausted from chamber 74. Spring 64 urges pushrod 62 to the service release position to release the brake.
[0037] When the vehicle operator wishes to actuate the parking brake, the operator may pull the button on control valve 22 to exhaust fluid, conduit 42. The loss in fluid pressure in conduit 42 allows fluid pressure from conduit 42 to flow from supply port 8 of valve 28 to delivery port D of valve 28 and through conduit 46 to the supply S and control ports C of valve 26. Fluid from supply port S of valve 26 flows outward from delivery port D of valve 26 to a predetermined pressure into conduit 48 to a control port of valve 32. This action causes delivery of fluid from fluid source 20 through valve 32 and conduit 54 to parking port. 56 of actuator 16 and into parking brake chamber
76 of actuator 16 on one side of parking diaphragm 66. Fluid pressure in chamber 76 parking pushrod 68 to the parking apply position and, consequently, service pushrod 62 to the sendee apply position against the force of spring 64 in order to apply the vehicle brakes. Fluid is also delivered through conduit 54 to fluid chamber 122 resulting in rotation of clutch 70 such that the clutch teeth 108 on clutch 70 are aligned with teeth 106 on pushrod 68. As a result, while pushrod 68 is able to move to the parking apply position freely, pushrod 68 is temporarily prevented from returning to the parking release position. Once the fluid pressure in chamber 76 reaches a predetermined level, valve 26 closes and the remaining fluid pressure in conduits 48, 54 is exhausted. Pressure is also vented from parking brake chamber 76. Because clutch 70 retains the position of parking pushrod 68, constant fluid pressure is not required for continued application of the parking brake. Further, the inventive braking system allows variation in the applied parking brake force without varying the size of the parking brake chamber. Rather, valve 26 can be adjusted to control the predetermined pressure at which further delivery of fluid is stopped.
[0038] When the vehicle operator wants to release the parking brake, the operator pushes in the control button on control valve 22 which increases fluid pressure in conduit 42. Because valve 24 is open (due to the prior absence of fluid pressure in conduit 42), fluid from conduit 42 initially flows through supply port S on valve 24 to delivery port D on valve 24 and into conduit 44. Fluid flow into conduit 44 occurs until a predetermined fluid pressure is reached and valve 24 closes and exhausts to atmosphere. Fluid in conduit 44 is delivered to a control port of valve 32. This action causes delivery of fluid from fluid source 20 through valve 32 and conduit 54 to parking port 56 and into parking brake chamber 76 of actuator 16 and also into fluid chamber 122 thereby causing rotation of clutch 70 such that clutch teeth 108 on clutch 70 are no longer aligned with the teeth 106 on pushrod 68. Once the predetermined pressure is reached, valves 24, 32 close and conduits 44, 54
(and parking brake chamber 76) are vented. Because the clutch teeth 108 on clutch 70 are no longer aligned with the teeth 106 on pushrod 68, spring 64 urges parking pushrod 68 to the parking release position (and service pushrod 62 to the service release position) to release the parking brake.
[0Θ39] A braking system 10 in accordance with the present invention represents an
improvement relative to conventional braking systems. The inventive braking system 10 enables application of the parking brake using fluid control rather than mechanical springs and can also maintain application of the parking brake during a loss of fluid pressure. As a result, the weight of the actuator is reduced, repair and replacement of the parking brake actuator is easier and safer than conventional spring-actuated parking brake actuators, and a constant fluid pressure is not required to maintain the actuator in a released state. A diaphragm is more durable than a parking spring which equates to longer life. The inventive braking system also permits selective release of the parking brake despite a leak or rupture in the fluid control system of the type that would result in actuation and locking of spring-actuated parking brake actuators. As a result, the vehicle is not immobilized and the vehicle and its occupants can be moved, if necessary, to a safer or more accessible location and/or out of the way of other vehicles. The inventive braking system also achieves the above benefits while using a conventional two-line fluid control system (i.e., one fluid control line to the service brake chamber and another fluid control line to the parking brake chamber)— unlike conventional fluid-actuated parking brake actuators that require a separate fluid control line to maintain the position of the parking brake actuator.
[0Θ40] While the invention has been shown and described with reference to one or more particular embodiments thereof, it will be understood by those of skill in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:
1. A brake actuator, comprising:
a housing defining a sendee brake chamber and a parking brake chamber;
a service diaphragm disposed within said sendee brake chamber;
a service pushrod disposed on a first side of said service diaphragm
a parking diaphragm disposed within said parking brake chamber;
a parking pushrod extending through said parking diaphragm, said parking pushrod having a first end disposed on a first side of said parking diaphragm and extending into said sendee brake chamber and disposed on a second side of said sendee diaphragm, said parking pushrod defining a first plurality of teeth;
a spring disposed within said sendee brake chamber on said first side of said sendee diaphragm and biasing said service pushrod to a service release position and said parking pushrod to a parking release position;
a clutch disposed about said parking pushrod and defining a clutch tooth on a radially inner surface configured for intermittent engagement with said first plurality of teeth of said parking pushrod; and
a clutch actuator configured to control rotation of said clutch
wherein introduction of fluid on said second side of said sendee diaphragm urges said service pushrod away from said service release position towards a service apply position, introduction of fluid on a second side of said parking diaphragm urges said parking pushrod away from said parking release position towards a parking apply position and said sendee pushrod away from said seniee release position towards said sendee apply position.
2. The brake actuator of claim 1 wherein rotation of said clutch moves said clutch tooth into and out of alignment with said first plurality of teeth on said parking pushrod and said clutch tooth has a profile such that, during alignment of said clutch tooth and said first plurality of teeth on said parking pushrod, movement of said parking pushrod is permitted in a first direction along a longitudinal axis of said parking pushrod away from said parking release position and towards said parking apply position and movement of said parking pushrod is inhibited in a second direction along said longitudinal axis opposite said first direction away from said parking apply position and towards said parking release position.
3. The brake actuator of claim 2 wherein introduction of fluid on said second side of said parking diaphragm and rotation of said clutch occurs simultaneously.
4. The brake actuator of claim 1 wherein said clutch defines a plurality of ratchet teeth on a radially outer surface and wherein said clutch actuator comprises:
a piston;
a pawl having a first end pivotally supported on said piston and a second end configured for engagement with one of said ratchet teeth on said clutch; and,
a spring biasing said second end of said pawl towards said clutch.
5. The brake actuator of claim 4 wherein said clutch defines four ratchet teet equally circumferentially spaced about said clutch.
6. The brake actuator of claim 1 wherein said first plurality of teeth on said parking pushrod are arranged in a first longitudinally extending row that extends over a first
circumferential portion of an outer surface of said parking pushrod.
7. The brake actuator of claim 6 wherein said parking pushrod includes a second plurality of teeth arranged in a second longitudinally extending row that extends over a second circumferential portion of said outer surface of said parking pushrod.
8. The brake actuator of claim 7 wherein a third circumferential portion of said outer surface of said parking pushrod between said first and second circumferential portions is untoothed.
9. The brake actuator of claim 7 wherein said first and second circumferential portions of said outer surface of said parking p shrod are diametrically opposite one another.
10, A brake actuator, comprising:
a housing defining a sendee brake chamber and a parking brake chamber;
a service diaphragm disposed within said service brake chamber;
a service pushrod disposed on a first side of said service diaphragm
a parking diaphragm disposed within said parking brake chamber;
a parking pushrod extending through said parking diaphragm, said parking pushrod having a first end disposed on a first side of said parking diaphragm and extending into said service brake chamber and disposed on a second side of said service diaphragm;
a spring disposed within said sendee brake chamber on said first side of said service diaphragm and biasing said service pushrod to a service release position and said parking pushrod to a parking release position;
means for holding said parking pushrod in a parking apply position.
wherein introduction of fluid on said second side of said service diaphragm urges said sendee pushrod away from said sendee release position towards a sendee apply position, introduction of fluid on a second side of said parking diaphragm urges said parking pushrod away from said parking release position towards said parking apply position and said service pushrod away from said service release position towards said sendee apply position.
11. The brake actuator of claim 10 wherein said holding means comprises : a clutch disposed about said parking pushrod and defining a clutch tooth on a radially inner surface; and
means for rotating said clutch
wherein rotation of said clutch moves said clutch tooth into and out of alignment with a first plurality of teeth on said parking pushrod and said clutch tooth has a profile such that, during alignment of said clutch tooth and said first plurality of teeth on said parking pushrod, movement of said parking pushrod is permitted in a first direction along a longitudinal axis of said parking pushrod away from said parking release position and towards said parking apply position and movement of said parking pushrod is inhibited in a second direction along said longitudinal axis opposite said first direction away from said parking apply position and towards said parking release position.
12. The brake actuator of claim 1 1 wherein introduction of fluid on said second side of said parking diaphragm and rotation of said clutch occurs simultaneously.
13. The brake actuator of claim 11 wherein said clutch defines a plurality of ratchet teeth on a radially outer surface and wherein said rotating means comprises:
a piston;
a pawl having a first end pivotal iy supported on said piston and a second end configured for engagement with one of said ratchet teeth on said clutch; and,
a spring biasing said second end of said pawl towards said clutch.
14. The brake actuator of claim 13 wherein said clutch defines four ratchet teeth equally circumferentiaily spaced about said clutch.
15. The brake actuator of claim 1 1 wherein said first plurality of teeth on said parking pushrod are arranged in a first longitudinally extending row that extends over a first
circumferential portion of an outer surface of said parking pushrod.
16. The brake actuator of claim 15 wherein said parking pushrod includes a second plurality of teeth arranged in a second longitudinally extending row that extends over a second circumferential portion of said outer surface of said parking pushrod.
17. The brake actuator of claim 16 wherein a third circumferential portion of said outer surface of said parking pushrod between said first and second circumferential portions is untoothed.
18. The brake actuator of claim 16 wherein said first and second circumferential portions of said outer surface of said parking pushrod are diametrically opposite one another.
19. A fluid controi system for a brake actuator, comprising:
a relay valve comprising
a delivery port in fluid communication with a parking brake chamber of the brake actuator; and
first and second control ports;
a first inversion valve comprising
a deliver}' port in fluid communication with said first control port of said relay valve;
a supply port in fluid communication with a fluid control conduit; and a controi port in fluid communication with said fluid control conduit; a second inversion valve comprising
a delivery port in fluid communication with said second control port of said relay valve;
a supply port; and
a controi port;
a third inversion valve comprising
a delivery port in fluid communication with said supply port of said second inversion valve and said control port of said second inversion valve;
a supply port in fluid communication with a fluid source; and, a control port in fluid communication with said fluid control conduit wherein a decrease in fluid pressure in said fluid control conduit enables delivery of fluid from said fluid source to said parking brake chamber and an increase in fluid pressure in said fluid control conduit enables exhaustion of fluid from said parking brake chamber.
20. The fluid control system of claim 19 wherein said relay val ve, said first inversion valve, said second inversion valve and said third inversion valve are disposed in a common housing.
21. A braking system, comprising:
a brake actuator comprising
a housing defining a service brake chamber and a parking brake chamber;
a sendee diaphragm disposed within said sendee brake chamber; a sendee pushrod disposed on a first side of said sendee diaphragm, introduction of fluid on a second side of said service diaphragm urging said sendee pushrod away from a service release position towards a service apply position;
a parking diaphragm disposed within said parking brake chamber and having a first side facing said service diaphragm, introduction of fluid on a second side of said parking diaphragm urging said service pushrod to said service apply position; and,
a fluid control system comprising
a relay valve comprising
a delivery port in fluid communication with said parking brake chamber of the brake actuator; and
first and second control ports;
a first inversion valve comprising
a delivery port in fluid communication with said first control port of said relay valve;
a supply port in fluid communication with a fluid control conduit; and a control port in fluid communication with said fluid control conduit; a second inversion valve comprising a delivery port in fluid communication with said second control port of said relay valve;
a sup ly port; and
a control port;
a third inversion valve comprising
a delivery port in fluid communication with said supply port of said second inversion valve and said control port of said second inversion valve;
a supply port in fluid communication with a fluid source; and,
a control port in fluid communication with said fluid control conduit wherein a decrease in fluid pressure in said fluid control conduit enables delivery of fluid from said fluid source to said parking brake chamber and an increase in fluid, pressure in said fluid control conduit enables exhaustion of fluid from said parking brake chamber.
22. The braking system of claim 21 wherein said brake actuator further comprises a spring disposed within said service brake chamber on said first side of said service diaphragm and biasing said service pushrod to a service release position and said parking pushrod to a parking release position.
23. The braking system of claim 21 wherein said brake actuator further comprises: a parking pushrod extending through said parking diaphragm, said parking pushrod having a first end disposed on said first side of said parking diaphragm and extending into said sendee brake chamber and disposed on said second side of said service diaphragm, said parking pushrod defining a first plurality of teeth;
a clutch disposed about said parking pushrod and defining a clutch tooth on a radially inner surface configured for intermittent engagement with said first plurality of teeth of said parking pushrod; and
a clutch actuator configured to control rotation of said clutch
wherein introduction of fluid on said second side of said parking diaphragm urges said parking pushrod away from a parking release position towards a parking apply position and rotation of said clutch moves said clutch tooth into and out of alignment with said first plurality of teeth on said parking pushrod and said clutch tooth has a profile such that, during alignment of said clutch tooth and said first plurality of teeth on said parking pushrod, movement of said parking pushrod is permitted in a first direction along a longitudinal axis of said parking pushrod away from said parking release position and towards said parking apply position and movement of said parking pushrod is inhibited in a second direction along said longitudinal axis opposite said first direction away from said parking apply position and towards said parking release position,
24. The braking system of claim 23 wherein introduction of fluid on said second side of said parking diaphragm and rotation of said clutch occurs simultaneously.
25. The braking system of claim 23 wherein said clutch defines a plurality of ratchet teeth on a radially outer surface and wherein said clutc actuator comprises:
a piston;
a pawl having a first end pivotally supported on said piston and a second end configured for engagement with one of said ratchet teeth on said clutch; and,
a spring biasing said second end of said pawl towards said clutch.
26. The brake actuator of claim 25 wherein said clutch defines four ratchet teeth equally circurnferentially spaced about said clutch.
27. The braking system of claim 23 wherein said first plurality of teeth on said parking pushrod are arranged in a first longitudinally extending row that extends over a first circumferential portion of an outer surface of said parking pushrod.
28. The braking system of claim 27 wherein said parking pushrod includes a second plurality of teeth arranged in a second longitudinally extending row that extends over a second circumferential portion of said outer surface of said parking pushrod.
99
29. The braking system of claim 28 wherein a third circumferential portion of said outer surface of said parking pushrod between said first and second c rcumferential portions is untoothed.
30. The braking system of claim 28 wherein said first and second circumferential portions of said outer surface of said parking pushrod are diametrically opposite one another.
PCT/US2014/049796 2013-08-07 2014-08-05 Braking system with non-spring parking brake actuator Ceased WO2015021050A2 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
RU2016102996A RU2633033C2 (en) 2013-08-07 2014-08-05 Brake system and drive mechanism of brake (versions)
AU2014306066A AU2014306066B2 (en) 2013-08-07 2014-08-05 Braking system with non-spring parking brake actuator
CN201480044461.7A CN105518332B (en) 2013-08-07 2014-08-05 Brakes with unsprung stop device actuator
CA2920255A CA2920255C (en) 2013-08-07 2014-08-05 Braking system with non-spring parking brake actuator
DE112014003649.8T DE112014003649B4 (en) 2013-08-07 2014-08-05 Brake system with springless parking brake actuator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US13/961,022 2013-08-07
US13/961,022 US9156458B2 (en) 2013-08-07 2013-08-07 Braking system with non-spring parking brake actuator

Publications (2)

Publication Number Publication Date
WO2015021050A2 true WO2015021050A2 (en) 2015-02-12
WO2015021050A3 WO2015021050A3 (en) 2015-07-16

Family

ID=51352882

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2014/049796 Ceased WO2015021050A2 (en) 2013-08-07 2014-08-05 Braking system with non-spring parking brake actuator

Country Status (7)

Country Link
US (1) US9156458B2 (en)
CN (1) CN105518332B (en)
AU (1) AU2014306066B2 (en)
CA (1) CA2920255C (en)
DE (1) DE112014003649B4 (en)
RU (1) RU2633033C2 (en)
WO (1) WO2015021050A2 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107847675B (en) 2015-06-19 2021-07-06 艾斯曲尔医疗公司 drug delivery device
DE102017114664B4 (en) * 2017-06-30 2023-03-02 Knorr-Bremse Systeme für Schienenfahrzeuge GmbH Spring-loaded brake cylinder with an emergency release device
US11186262B2 (en) * 2018-10-11 2021-11-30 Bendix Commercial Vehicle Systems Llc System and method for controlling compounding in a brake actuator
EP3663149B1 (en) * 2018-12-06 2023-03-29 IMS Gear SE & Co. KGaA Locking device for an electromechanical brake of motor vehicle brake, electromechanical brake provided with such a locking device and motor vehicle equipped with such an electromechanical brake
US10427666B1 (en) * 2019-02-13 2019-10-01 Leonard Van Haecke Brake installation measurement and verification system
EP3695993B1 (en) * 2019-02-15 2022-07-06 KNORR-BREMSE Systeme für Nutzfahrzeuge GmbH Pneumatic control unit
US11639166B2 (en) * 2020-02-17 2023-05-02 Tse Brakes, Inc. Spring brake actuators

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE563954A (en) 1957-02-13
GB955062A (en) 1961-07-05 1964-04-15 Bendix Westinghouse Automotive Brake mechanism with mechanical lock
US3410610A (en) 1966-07-08 1968-11-12 Rockwell Standard Company Parking and emergency brake system for vehicle
US3450008A (en) 1966-10-27 1969-06-17 Wagner Electric Corp Friction device operating mechanism
DE3046669A1 (en) 1980-12-11 1982-07-22 Wabco Fahrzeugbremsen Gmbh, 3000 Hannover MECHANICAL QUICK RELEASE DEVICE FOR SPRING-STORAGE BRAKE CYLINDER
US4907842A (en) 1988-10-27 1990-03-13 International Transquip Industries Vehicle air brake system and valves for it
US5036961A (en) 1990-03-16 1991-08-06 Allied-Signal Inc. Auxiliary parking brake system
RU2070522C1 (en) * 1990-05-14 1996-12-20 Гродненский завод автомобильных агрегатов Brake chamber
US5353688A (en) * 1992-06-26 1994-10-11 Nai Anchorlok, Inc. Tamper-resistant brake actuator
CN1093057C (en) * 1995-02-21 2002-10-23 奈安乔洛克公司 Spring brake with filtered breather
DE19853718C2 (en) 1998-11-20 2001-05-23 Knorr Bremse Systeme Parking and maneuvering valve for trailer vehicles with a spring-loaded parking brake
DE10148480A1 (en) 2001-10-01 2003-04-17 Knorr Bremse Systeme Parking brake device and method for actuating the parking brake
DE102005001234A1 (en) 2005-01-11 2006-07-20 Wabco Gmbh & Co.Ohg Brake cylinder with parking brake function
ITTO20050498A1 (en) 2005-07-20 2007-01-21 Knorr Bremse Systeme PNEUMATIC SYSTEM FOR BRAKING A COMMERCIAL VEHICLE
US8079649B2 (en) 2009-01-16 2011-12-20 Bendix Commercial Vehicle Systems, Llc Vehicle condition dependent supplemental parking brake system with protection against an unwanted application
US8127903B2 (en) 2010-03-12 2012-03-06 Bendix Spicer Foundation Brake Llc Integral light weight spring brake actuator and mount
RU100983U1 (en) * 2010-10-11 2011-01-10 Григорий Николаевич Колей BRAKE CAMERA WITH SPRING ENERGY ACCUMULATOR
US9802593B2 (en) 2011-06-07 2017-10-31 Bendix Commercial Vehicle Systems Llc Multi-pressure valve controller and method for a vehicle braking system
DE102012002730A1 (en) 2012-02-10 2013-08-14 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Combined service and parking brake cylinder with lockable together with the parking brake piston diaphragm
US8978839B2 (en) * 2012-05-07 2015-03-17 Haldex Brake Products Corporation Pneumatic brake actuator with flow insensitive two way control valve

Also Published As

Publication number Publication date
WO2015021050A3 (en) 2015-07-16
CN105518332A (en) 2016-04-20
US20150041260A1 (en) 2015-02-12
DE112014003649B4 (en) 2019-03-28
US9156458B2 (en) 2015-10-13
RU2016102996A (en) 2017-09-15
CA2920255A1 (en) 2015-02-12
DE112014003649T5 (en) 2016-05-04
CA2920255C (en) 2018-04-24
CN105518332B (en) 2017-12-12
RU2633033C2 (en) 2017-10-11
AU2014306066B2 (en) 2016-09-22
AU2014306066A1 (en) 2016-02-04

Similar Documents

Publication Publication Date Title
CA2920255C (en) Braking system with non-spring parking brake actuator
US10619738B2 (en) Parking brake system
US3547234A (en) Dual range brake system for vehicles
US7300118B2 (en) Electronic park brake valve system for air brakes vehicles
US10501099B2 (en) Rail vehicle braking system and braking method for a rail vehicle comprising such a system
US20140183935A1 (en) Vehicle Braking System
US10065617B2 (en) Apparatus and method for isolating an intact portion of a service braking circuit from a failed service brake wheel end
US3272566A (en) Combined service and emergency brake system apparatus
US4589704A (en) Air brake with collet locked push rod and air supply system
US7658453B2 (en) Service brake relay with integrated quick release valve
GB2074272A (en) Hydraulic braking system
US2041884A (en) Brake mechanism
GB1572812A (en) Brake actuators
EP2414203B2 (en) Braking control system
US20070284938A1 (en) Hydraulic release system with manually operated hydraulic lock valve for spring-applied, hydraulically-released parking brake system
US4696521A (en) Vehicle anti-skid air braking systems
WO2012049649A1 (en) Fail-safe brake system
AU2014277743B2 (en) Rail vehicle braking system and braking method for a rail vehicle comprising such a system
EP0654387B1 (en) Fluid pressure operable spring force actuators
JPH07323834A (en) Parking brake release device of vehicle
TWI281447B (en) A pneumatic closed-looped antilock pressure modulating device for pneumatic brake systems
GB2061385A (en) Pneumo-mechanical braking cylinder for pneumatic braking systems in vehicles
GB2341662A (en) Safety device for braking systems of articulated vehicles

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14750967

Country of ref document: EP

Kind code of ref document: A2

ENP Entry into the national phase

Ref document number: 2920255

Country of ref document: CA

ENP Entry into the national phase

Ref document number: 2014306066

Country of ref document: AU

Date of ref document: 20140805

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 112014003649

Country of ref document: DE

ENP Entry into the national phase

Ref document number: 2016102996

Country of ref document: RU

Kind code of ref document: A

122 Ep: pct application non-entry in european phase

Ref document number: 14750967

Country of ref document: EP

Kind code of ref document: A2