CA2818422A1 - Automatic lift axle control system - Google Patents
Automatic lift axle control system Download PDFInfo
- Publication number
- CA2818422A1 CA2818422A1 CA2818422A CA2818422A CA2818422A1 CA 2818422 A1 CA2818422 A1 CA 2818422A1 CA 2818422 A CA2818422 A CA 2818422A CA 2818422 A CA2818422 A CA 2818422A CA 2818422 A1 CA2818422 A1 CA 2818422A1
- Authority
- CA
- Canada
- Prior art keywords
- lift
- air bag
- port
- axle suspension
- trailer
- 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.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
- B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
- B60G17/052—Pneumatic spring characteristics
- B60G17/0523—Regulating distributors or valves for pneumatic springs
- B60G17/0526—Distributor units, e.g. for retractable wheels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2200/00—Indexing codes relating to suspension types
- B60G2200/30—Rigid axle suspensions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
- B60G2202/10—Type of spring
- B60G2202/15—Fluid spring
- B60G2202/152—Pneumatic spring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
- B60G2204/10—Mounting of suspension elements
- B60G2204/12—Mounting of springs or dampers
- B60G2204/126—Mounting of pneumatic springs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
- B60G2204/40—Auxiliary suspension parts; Adjustment of suspensions
- B60G2204/47—Means for retracting the suspension
- B60G2204/4702—Means for retracting the suspension pneumatically
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2300/00—Indexing codes relating to the type of vehicle
- B60G2300/04—Trailers
- B60G2300/042—Semi-trailers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2500/00—Indexing codes relating to the regulated action or device
- B60G2500/20—Spring action or springs
- B60G2500/202—Height or leveling valve for air-springs
- B60G2500/2021—Arrangement of valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
- B60G2600/21—Self-controlled or adjusted
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2800/00—Indexing codes relating to the type of movement or to the condition of the vehicle and to the end result to be achieved by the control action
- B60G2800/20—Stationary vehicle
- B60G2800/205—Stationary vehicle jacking-up for changing tyre or vehicle inspection
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vehicle Body Suspensions (AREA)
Abstract
An automatic valve system for raising lift axles in unloaded trailers and lowering them in loaded trailers has a double pilot, five port, two position spool valve. When the fixed axle suspension air bag is inflated, by the height control valve when the trailer is loaded, the spool is moved by the pressure of the fixed axle suspension air bag into working position, where the lift axle lift bag is deflated by connection to atmosphere, and the lift axle suspension air bag is inflated by compressed air lowering the lift axle, When the trailer is unloaded the spool is moved into normal position by a reduced compressed air pressure, the lift axle lift bags are inflated by compressed air, and the lift axle suspension air bag is deflated to atmosphere, raising the lift axle. This is purely automatic without driver control. An manual exhaust valve is provided so the driver can raise and lower the lift axle to change tires and the like.
Description
ak 02818422 2013-06-18 AUTOMATIC LIFT AXLE CONTROL SYSTEM
Field of Invention This invention is directed to an automatic control system for lift axles in trailers, which includes a valve arrangement which automatically controls a lift axle suspension. Such control systems raise lift axles when the trailer is unloaded and lower them when the trailer is loaded.
Background of Invention Lift axles are well known, generally they are raised when the trailer is not loaded and lowered when the trailer is loaded.
The height on the down or fixed axle is controlled by a height control valve (sometimes called a leveling valve) which is usually purely mechanical. Typically the height control valve is mounted on the chassis and has a supply or inlet port connected to the compressed air line and tank, an exhaust or dump port connecting to the atmosphere and an air spring or suspension bag port connecting to the down axle suspension bag. Suspension bags may also be called air bags, air balloons, air bellows, air coils, or air springs. A
lever or control arm, usually horizontal on the control valve controls air flow. A linkage, usually a rod sometimes called a connector, connects the lever, usually vertically, to the axle or its axle spring, typically pivotally at both ends. If the chassis is below a preset chassis ride height measured from axle centre to the chassis (typically 17 inches, 43 cm, although it may vary from 15 inches, 38 cm or less, to 19 inches, 48 cm or more) the lever moves the control valve to connect the supply port to the air spring port so that the air flow connects the air supply to the down axle suspension bag(s) pressurizing and inflating the down axle suspension bag (s), and raising the chassis. If the chassis is ' above the preset ride height the lever moves the control valve to connect.the air spring port to the exhaust port lowering the pressure in and deflating the down suspension bag(s). Typically the down suspension bag has a pressure of 62 psi when loaded, and 11 psi when unloaded. As the trailer is loaded the chassis sinks actuating the height control valve, and air flows into the down suspension bag increasing the pressure, until the chassis reaches the ride height, this process continues until the trailer is loaded, when the height control valve shuts off the supply port. If the trailer is partly loaded the pressure may be less than 62 psi, if overloaded greater perhaps as much as 100 psi. Typically the trailer's compressed air source is a compressed air tank with an associated pump which maintains the pressure.
Control systems for lift axles are known, which are usually controlled from the driver's cab of the tractor. This is believed to have led to abuse of lift axles, primarily by leaving them down when not required, which increases wear and fuel consumption. If lift axles are raised when not required, tires and brake drums can be rotated between the lift and down axles to greatly increase tire and brake life. Suspension components such as bushings and shock absorbers last longer. The trailer structure and, for that matter, the tractor, experiences a smoother ride with less trailer axles down. Less tires on the ground means less tires wearing out, means less tires in the landfill. Less tires on the road means less damage and wear to the roadway, especially when turning on asphalt road surfaces. Less tires on the road means easier pulling, which translates to better fuel efficiency. Less fuel being burned means less emission into the atmosphere, less pollution, and less damage to our ecology. Operator-activated lift axles are subject to operator abuse/error/misuse and automatic lift axles have less chance of operator error. Electric-over-air valving has a pressure-sensitive switch that activates the lift valve, while air-over-air
Field of Invention This invention is directed to an automatic control system for lift axles in trailers, which includes a valve arrangement which automatically controls a lift axle suspension. Such control systems raise lift axles when the trailer is unloaded and lower them when the trailer is loaded.
Background of Invention Lift axles are well known, generally they are raised when the trailer is not loaded and lowered when the trailer is loaded.
The height on the down or fixed axle is controlled by a height control valve (sometimes called a leveling valve) which is usually purely mechanical. Typically the height control valve is mounted on the chassis and has a supply or inlet port connected to the compressed air line and tank, an exhaust or dump port connecting to the atmosphere and an air spring or suspension bag port connecting to the down axle suspension bag. Suspension bags may also be called air bags, air balloons, air bellows, air coils, or air springs. A
lever or control arm, usually horizontal on the control valve controls air flow. A linkage, usually a rod sometimes called a connector, connects the lever, usually vertically, to the axle or its axle spring, typically pivotally at both ends. If the chassis is below a preset chassis ride height measured from axle centre to the chassis (typically 17 inches, 43 cm, although it may vary from 15 inches, 38 cm or less, to 19 inches, 48 cm or more) the lever moves the control valve to connect the supply port to the air spring port so that the air flow connects the air supply to the down axle suspension bag(s) pressurizing and inflating the down axle suspension bag (s), and raising the chassis. If the chassis is ' above the preset ride height the lever moves the control valve to connect.the air spring port to the exhaust port lowering the pressure in and deflating the down suspension bag(s). Typically the down suspension bag has a pressure of 62 psi when loaded, and 11 psi when unloaded. As the trailer is loaded the chassis sinks actuating the height control valve, and air flows into the down suspension bag increasing the pressure, until the chassis reaches the ride height, this process continues until the trailer is loaded, when the height control valve shuts off the supply port. If the trailer is partly loaded the pressure may be less than 62 psi, if overloaded greater perhaps as much as 100 psi. Typically the trailer's compressed air source is a compressed air tank with an associated pump which maintains the pressure.
Control systems for lift axles are known, which are usually controlled from the driver's cab of the tractor. This is believed to have led to abuse of lift axles, primarily by leaving them down when not required, which increases wear and fuel consumption. If lift axles are raised when not required, tires and brake drums can be rotated between the lift and down axles to greatly increase tire and brake life. Suspension components such as bushings and shock absorbers last longer. The trailer structure and, for that matter, the tractor, experiences a smoother ride with less trailer axles down. Less tires on the ground means less tires wearing out, means less tires in the landfill. Less tires on the road means less damage and wear to the roadway, especially when turning on asphalt road surfaces. Less tires on the road means easier pulling, which translates to better fuel efficiency. Less fuel being burned means less emission into the atmosphere, less pollution, and less damage to our ecology. Operator-activated lift axles are subject to operator abuse/error/misuse and automatic lift axles have less chance of operator error. Electric-over-air valving has a pressure-sensitive switch that activates the lift valve, while air-over-air
2 CD, 02818422 2013-06-18 valving has an air shuttle that is activated by pressure side to side. Recent regulation in both Alberta and Manitoba regulations as they pertain to trailers specify that the control to raise, lower, or vary the load on an axle unit cannot be operated from the driver's compartment. This is primarily a safety measure to prevent truckers having lift axles down when the trailer is unloaded, or up when the trailer is loaded.
In effect this control system is that required in Western Canada, Alberta, British Columbia, Manitoba and Saskatchewan. These regulations are best described in the Government of Alberta's Transport Engineering Weight and Dimension Policy at http://trailer-bodybuilders.com/mag/trucks_push canada_liftaxle/, which specify that the load sensing/control device shall be one of the following approved devices:
Yak's axle assist device;
Haldex ILAS III valve;
Mentor WABCO KIT 400 850 820 0;
Sealco LSAS IIA;
Wheel Monitor Balancer B150.
These devices are to ensure that: the axle lift device may have an axle lifted only when the trailer is empty; when the trailer is partly or fully loaded, the axle lift device shall automatically have all axles on the ground; the owner or operator shall not modify the device.
The precise structure of these devices is not available to the public to applicant's knowledge. Those devices applicant is aware of are sealed units and their internal structures are not obvious from the outside, nor were they ascertainable by internet search, the devices presumably contain at least one valve. Applicant is familiar with and has installed a number of Haldex ILAS III valves
In effect this control system is that required in Western Canada, Alberta, British Columbia, Manitoba and Saskatchewan. These regulations are best described in the Government of Alberta's Transport Engineering Weight and Dimension Policy at http://trailer-bodybuilders.com/mag/trucks_push canada_liftaxle/, which specify that the load sensing/control device shall be one of the following approved devices:
Yak's axle assist device;
Haldex ILAS III valve;
Mentor WABCO KIT 400 850 820 0;
Sealco LSAS IIA;
Wheel Monitor Balancer B150.
These devices are to ensure that: the axle lift device may have an axle lifted only when the trailer is empty; when the trailer is partly or fully loaded, the axle lift device shall automatically have all axles on the ground; the owner or operator shall not modify the device.
The precise structure of these devices is not available to the public to applicant's knowledge. Those devices applicant is aware of are sealed units and their internal structures are not obvious from the outside, nor were they ascertainable by internet search, the devices presumably contain at least one valve. Applicant is familiar with and has installed a number of Haldex ILAS III valves
3 on trailers, which the operators found unsatisfactory. The device did not work well or sometimes at all at low temperatures, undefined but below 0 F, -18 C, also dirt, such as summer dust, and other contamination has a similar effect, which is an extreme inconvenience to truckers and the trucking industry especially in the Canadian winter, when temperatures below -30 C are routine.
It is thought that the failure of the device to work, when it seizes up, is a combination of winter cold and condensation, corrosion due road chemicals, which are typically calcium, sodium and magnesium chloride, and summer dust, although this was not verified. The operators asked applicant to devise an effective control valve, which applicant did as related below. This device was road tested experimentally in black box form, its precise structure was not made public. This device was subsequently been tested and approved for installation as a load sensing/control device under the title "Midland Auto Lift" in accordance with the above-noted regulations. Further several Haldex ILAS III valves, which operators found unsatisfactory were replaced by Midland Auto Lift and found to work satisfactorily, under warranty. There are also problems with the Sealco LSAS II A system, but applicant is not aware of the detail, degree and scope of the failures.
Although applicant was not cognizant of the internal structures of the approved valves, it seemed apparent some form of spool valve was involved. One tested design which was similar to the device discussed below except the spool was piston controlled in a cylinder by the preset reduced gauge pressure on one side and the down axle suspension bag pressure on the other. The device did not work, the piston rod was attached to the spool end by an adaptor and although officially the identical size to the spool with the identical engineering tolerances, the piston rod stuck in the spool valve.
It is thought that the failure of the device to work, when it seizes up, is a combination of winter cold and condensation, corrosion due road chemicals, which are typically calcium, sodium and magnesium chloride, and summer dust, although this was not verified. The operators asked applicant to devise an effective control valve, which applicant did as related below. This device was road tested experimentally in black box form, its precise structure was not made public. This device was subsequently been tested and approved for installation as a load sensing/control device under the title "Midland Auto Lift" in accordance with the above-noted regulations. Further several Haldex ILAS III valves, which operators found unsatisfactory were replaced by Midland Auto Lift and found to work satisfactorily, under warranty. There are also problems with the Sealco LSAS II A system, but applicant is not aware of the detail, degree and scope of the failures.
Although applicant was not cognizant of the internal structures of the approved valves, it seemed apparent some form of spool valve was involved. One tested design which was similar to the device discussed below except the spool was piston controlled in a cylinder by the preset reduced gauge pressure on one side and the down axle suspension bag pressure on the other. The device did not work, the piston rod was attached to the spool end by an adaptor and although officially the identical size to the spool with the identical engineering tolerances, the piston rod stuck in the spool valve.
4 The advantages are that the design is simple with one moving part, the spool. The system is sealed with the exception of the spool valve exhaust port, which basically lets air out of the system, but not in.
DESCRIPTION OF THE INVENTION
The invention in one broadest aspect is directed to a trailer having a chassis at least one fixed axle having at least one associated fixed axle suspension air bag supporting said chassis, a lift axle having at least one associated lift air bag, and an automatic control valve for said lift axle and a source of compressed air.
Preferably the automatic control valve comprises a double pilot, five port spool valve with a spool. The spool valve has a first pilot port at one end connected to at least one fixed axle suspension air bag, and a second pilot port at the other end of said spool valve connected to the source of compressed air through a pressure reduction valve setting said compressed air to a reduced pressure, optionally and preferably a manual exhaust valve is between the pressure reduction valve and the second pilot valve.
When the trailer is unloaded the pressure in the first pilot port and the fixed axle suspension air bag is less than the reduced pressure in the second pilot port. The reduced pressure moves the spool into first normal position adjacent the first pilot port.
In first normal position the spool valve connects the compressed air source to the at least one lift axle lift air bag, thus inflating the at least one lift axle lift air bag and simultaneously the spool valve connects the at least one lift axle suspension air bag to atmosphere deflating said lift axle suspension air bag, whereby said lift axle is raised when said trailer is unloaded. When the trailer is loaded the first pilot
DESCRIPTION OF THE INVENTION
The invention in one broadest aspect is directed to a trailer having a chassis at least one fixed axle having at least one associated fixed axle suspension air bag supporting said chassis, a lift axle having at least one associated lift air bag, and an automatic control valve for said lift axle and a source of compressed air.
Preferably the automatic control valve comprises a double pilot, five port spool valve with a spool. The spool valve has a first pilot port at one end connected to at least one fixed axle suspension air bag, and a second pilot port at the other end of said spool valve connected to the source of compressed air through a pressure reduction valve setting said compressed air to a reduced pressure, optionally and preferably a manual exhaust valve is between the pressure reduction valve and the second pilot valve.
When the trailer is unloaded the pressure in the first pilot port and the fixed axle suspension air bag is less than the reduced pressure in the second pilot port. The reduced pressure moves the spool into first normal position adjacent the first pilot port.
In first normal position the spool valve connects the compressed air source to the at least one lift axle lift air bag, thus inflating the at least one lift axle lift air bag and simultaneously the spool valve connects the at least one lift axle suspension air bag to atmosphere deflating said lift axle suspension air bag, whereby said lift axle is raised when said trailer is unloaded. When the trailer is loaded the first pilot
5 'port and the fixed axle suspension air bag are connected to the compressed air source and the pressure in the first pilot port is greater than the reduced pressure in the second pilot port. This greater pressure moves the spool into second working position adjacent said second pilot port. In second working condition the spool valve connects the at least one lift axle lift bag to atmosphere deflating said at least one lift axle lift air bag.
Simultaneously the spool valve connects said at least one lift axle suspension air bag to the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered when said trailer is loaded.
As can be ascertained the raising and lowering of the lift axle are purely automatic and cannot be controlled by the driver.
Typically the trailer has a chassis on which is mounted a height control valve having a supply port connected to said compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag. The chassis has a ride height, which is usually a specific set height. The chassis is below this ride height when the trailer is loaded. The height control valve then connects the supply port to the output port supplying compressed air to the at least one fixed axle suspension air bag increasing the pressure of said at least one fixed axle suspension bag. The chassis is above the ride height when the trailer is unloaded and the height control valve connects the output port to said exhaust port lowering the pressure of the at least one fixed axle suspension air bag.
Typically the height control valve has a level arm pivotally connected at the end remote from the valve to an upright rod, which is pivotally connected at its lower end to a fixed axle, said lever arm actuating the connection of said output port to said exhaust port when said chassis is above said ride height when the trailer
Simultaneously the spool valve connects said at least one lift axle suspension air bag to the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered when said trailer is loaded.
As can be ascertained the raising and lowering of the lift axle are purely automatic and cannot be controlled by the driver.
Typically the trailer has a chassis on which is mounted a height control valve having a supply port connected to said compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag. The chassis has a ride height, which is usually a specific set height. The chassis is below this ride height when the trailer is loaded. The height control valve then connects the supply port to the output port supplying compressed air to the at least one fixed axle suspension air bag increasing the pressure of said at least one fixed axle suspension bag. The chassis is above the ride height when the trailer is unloaded and the height control valve connects the output port to said exhaust port lowering the pressure of the at least one fixed axle suspension air bag.
Typically the height control valve has a level arm pivotally connected at the end remote from the valve to an upright rod, which is pivotally connected at its lower end to a fixed axle, said lever arm actuating the connection of said output port to said exhaust port when said chassis is above said ride height when the trailer
6 is unloaded, said lever arm actuating the connection of said supply port to said output port when said chassis is below said ride height when the trailer is loaded. The upright rod need not be connected directly to the axle at its lower end but it must have a fixed relation to the axle.
In a second broadest aspect the invention is directed to an automatic control valve system for a lift axle for a trailer comprising a five port, double pilot port, spool valve. This valve system comprises a cylindrical tube containing a spool, first and second end pilot ports, and five side ports. The spool is slidable in the cylindrical tube and has airtight opposed end lands and a middle airtight land separated by first and second grooves. The first groove is adjacent said first pilot port, ther second groove is adjacent said second pilot port. These side ports are spaced longitudinally apart along the cylinder.
The first side port is connected to atmosphere.
The second side port is connected to at least one lift axle suspension air bag.
The third side port and the first pilot port are connected to at least one fixed axle suspension air bag. Which itself is connected through a height control valve to a compressed air source.
The fourth port is connected to at least one lift axle lift air = bag.
The fifth port is connected to said compressed air source.
The second pilot port is connected to said compressed air source through a pressure reduction valve.
The spool has two positions a first normal position when the at least one fixed axle suspension air bag is at low pressure, that is when the trailer is unloaded, and a second working position when the at least one fixed axle suspension air bag is at high pressure, that is when the trailer is loaded.
In a second broadest aspect the invention is directed to an automatic control valve system for a lift axle for a trailer comprising a five port, double pilot port, spool valve. This valve system comprises a cylindrical tube containing a spool, first and second end pilot ports, and five side ports. The spool is slidable in the cylindrical tube and has airtight opposed end lands and a middle airtight land separated by first and second grooves. The first groove is adjacent said first pilot port, ther second groove is adjacent said second pilot port. These side ports are spaced longitudinally apart along the cylinder.
The first side port is connected to atmosphere.
The second side port is connected to at least one lift axle suspension air bag.
The third side port and the first pilot port are connected to at least one fixed axle suspension air bag. Which itself is connected through a height control valve to a compressed air source.
The fourth port is connected to at least one lift axle lift air = bag.
The fifth port is connected to said compressed air source.
The second pilot port is connected to said compressed air source through a pressure reduction valve.
The spool has two positions a first normal position when the at least one fixed axle suspension air bag is at low pressure, that is when the trailer is unloaded, and a second working position when the at least one fixed axle suspension air bag is at high pressure, that is when the trailer is loaded.
7 In.first normal position the first groove of the spool connects the fourth and fifth side ports and the compressed air source to the lift axle lift air bag inflating the lift axle lift air bag, while the second grove of said spool connects said first and second side ports deflating said at least one lift axle suspension air bag, which raises the lift axle.
In second normal position, the first groove of the spool connects the first and fourth side ports connects the lift axle suspension air bag to atmosphere deflating the lift axle suspension air bag, while the second groove of the spool connects the second and third side ports connecting the lift axle suspension air bag to the first pilot port and the at least one fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag, which lowers the lift axle.
Preferably the pressure reduction valve is connected to said second pilot port through a manual exhaust valve. Also preferably the compressed air source is connected to the at least one fixed axle suspension air bag and the third side port and the first pilot port through a height control valve, which supplies compressed air at slightly less pressure. Typically the height control valve has a supply port connected to the compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag. The height control valve is mounted on a chassis having a ride height, when the chassis is below the ride height and the trailer is loaded the height control valve connects the supply port to the output port supplying compressed air to the at least one fixed axle suspension air bag increasing the pressure of the at least one fixed axle suspension bag. When the chassis is above the ride height and the trailer is unloaded the height control valve connects the output port to the exhaust port lowering the pressure of the at least one fixed axle suspension air bag,
In second normal position, the first groove of the spool connects the first and fourth side ports connects the lift axle suspension air bag to atmosphere deflating the lift axle suspension air bag, while the second groove of the spool connects the second and third side ports connecting the lift axle suspension air bag to the first pilot port and the at least one fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag, which lowers the lift axle.
Preferably the pressure reduction valve is connected to said second pilot port through a manual exhaust valve. Also preferably the compressed air source is connected to the at least one fixed axle suspension air bag and the third side port and the first pilot port through a height control valve, which supplies compressed air at slightly less pressure. Typically the height control valve has a supply port connected to the compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag. The height control valve is mounted on a chassis having a ride height, when the chassis is below the ride height and the trailer is loaded the height control valve connects the supply port to the output port supplying compressed air to the at least one fixed axle suspension air bag increasing the pressure of the at least one fixed axle suspension bag. When the chassis is above the ride height and the trailer is unloaded the height control valve connects the output port to the exhaust port lowering the pressure of the at least one fixed axle suspension air bag,
8 CD, 02818422 2013-06-18 =
Most typically the height control valve has a level arm pivotally connected at the end remote from the valve to an upright rod, which is pivotally connected at its lower end to a fixed axle, the lever arm actuates the connection of the output port to the exhaust port when the chassis is above the ride height when the trailer is unloaded. The lever arm actuates the connection of the supply port to the output port when the chassis is below said ride height when the trailer is loaded.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a schematic longitudinal sectional view of a spool valve of the invention in first normal position.
Fig. 2 shows a schematic longitudinal sectional view of a spool valve of the invention in second working position.
Fig. 3 shows a schematic view of the valve of Figs. 1 and 2 incorporated in a pneumatic system using compressed air on a trailer.
Fig. 4 shows a schematic view of the height control valve as used the invention.
Fig. 5 shows a schematic view of an embodiment of the invention as installed in a containment box.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Schematic sectional longitudinal views of spool valve 11 are shown in Figs. 1 and 2. Spool valve 11 has body 13 with internal bore 15 containing spool 19. Endcaps 21 and 23 have pilot ports 25 and 27 respectively communicating with pilot chambers 28 and 30. Body 13 has five ports 31, 32, 33, 34 and 35, which are conventionally labelled 1, 2, 3, 4, and 5 respectively in the art. In use port 31 is the exhaust to air/atmosphere port 32 is connected to the lift
Most typically the height control valve has a level arm pivotally connected at the end remote from the valve to an upright rod, which is pivotally connected at its lower end to a fixed axle, the lever arm actuates the connection of the output port to the exhaust port when the chassis is above the ride height when the trailer is unloaded. The lever arm actuates the connection of the supply port to the output port when the chassis is below said ride height when the trailer is loaded.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a schematic longitudinal sectional view of a spool valve of the invention in first normal position.
Fig. 2 shows a schematic longitudinal sectional view of a spool valve of the invention in second working position.
Fig. 3 shows a schematic view of the valve of Figs. 1 and 2 incorporated in a pneumatic system using compressed air on a trailer.
Fig. 4 shows a schematic view of the height control valve as used the invention.
Fig. 5 shows a schematic view of an embodiment of the invention as installed in a containment box.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Schematic sectional longitudinal views of spool valve 11 are shown in Figs. 1 and 2. Spool valve 11 has body 13 with internal bore 15 containing spool 19. Endcaps 21 and 23 have pilot ports 25 and 27 respectively communicating with pilot chambers 28 and 30. Body 13 has five ports 31, 32, 33, 34 and 35, which are conventionally labelled 1, 2, 3, 4, and 5 respectively in the art. In use port 31 is the exhaust to air/atmosphere port 32 is connected to the lift
9 'axle suspension bag, port 33 is connected to the down axle suspension bag, port 34 is connected to the lift axle lift bag, and port 35 is connected to the compressed air tank or source typically at 110 psi. Pilot port 27 is connected via a pressure reduction device to the compressed air tank or source at 50 psi. Pilot port 25 is connected to the down axle suspension bag. When the down axle suspension bag is at low pressure around 11 psi the reduced pressure 50 psi from the pressure reduction device moves spool 19 toward pilot port 25 as is shown in Fig 1. When port 34 is connected to port 35 and thus the compressed air source is connected to the lift axle lift bag inflating the lift bag and raising the lift axle. Port 32 is connected to port 31, thus connecting the lift axle suspension bag to exhaust, deflating the lift axle suspension bag and allowing the lift axle to rise. As shown spool 19 has end landings 36 and 40 and middle landing 38 which slidably engage bore 15, separated by reduced diameter portions 42 and 44 forming recesses 46 and 48, Landings 36, 38 and 40 have conventional annular seals, typically 0-rings (not shown) to maintain a seal between recesses 46 and 48 and recess 46 and end bore 28 and recess 48 and end bore 30. When as in Fig. 2 the down suspension bag is at high pressure typically 62 psi (the trailer is loaded) spool 19 is moved toward aperture 27 against the reduced pressure 50 psi from the pressure reduction device. In Fig. 2 port 34 is connected to port 31 which connects the lift axle lift bag to exhaust deflating the lift axle lift bag and lowering the lift axle. Port 32 is connected to port 33 which connects the compressed air source to the lift axle suspension bag which then inflates supporting the trailer. In general a pressure differential of about
10 psi is required to move spool 19 in either direction.
Fig. 3 shows pneumatic system 10 which has compressed air source 49, typically a tank maintained at 110 psi, usually 5 psi, which supplies compressed air to system 10 via pneumatic line 50.
= Pneuthatic line 53 connects air source 49 to height control valve 62. When the trailer is loaded and below the set chassis height, typically 18 inches (46 cm), height control valve 62 supplies air to airline 66 which inflates down axle suspension bag 64 to carry the load on down axle 65. When the trailer is unloaded the chassis rises and height control valve 62 prevents airline 53 supplying compressed air to line 63. Height control valve 62 opens exhaust port 73 discharging the pressure in down axle suspension bag 64.
This arrangement or a closely similar arrangement is common to most trailers, which typically have two down suspension bags 64 for each axle, and usually four such bags, two for each axle. In the preferred embodiment T joint 66 in airline 63 connects airline 66 and suspension bag 64 to airline 67. Airline 67 connects to T joint 75 which connects via airline 76 to port 33 and via airline 77 to axial aperture 25 of spool valve 11. Chassis 101 is indicated by the broken line.
Airline 51 connects compressed air source 49 via T joint 74 to airlines 51 and 52. Airline 51 connects air source 49 to port 35.
Airline 52 connects compressed air source 49 to pressure regulator 54, which reduces the pressure to around 50 psi. Pressure regulator 54 has pressure gauge 55 to measure the output pressure and manual control 56 to adjust the pressure usually within 5 psi.
Airline 57 is connected through manual override valve 58 (a T
switch), which has exhaust port 60 and manual control 59 to airline 61 which connects to axial aperture 27. Manual override valve 58 may be used to reduce the pressure to atmospheric. The reduced pressure in airline 61 and thus axial aperture 27 moves spool 19 toward axial aperture 25 as shown in Fig. 1, when the pressure in airline 67 and axial aperture 25 is below 40 psi.
When the trailer is loaded height control valve 62 connects air source 49 to down axle suspension bag 64 which is at high pressure
Fig. 3 shows pneumatic system 10 which has compressed air source 49, typically a tank maintained at 110 psi, usually 5 psi, which supplies compressed air to system 10 via pneumatic line 50.
= Pneuthatic line 53 connects air source 49 to height control valve 62. When the trailer is loaded and below the set chassis height, typically 18 inches (46 cm), height control valve 62 supplies air to airline 66 which inflates down axle suspension bag 64 to carry the load on down axle 65. When the trailer is unloaded the chassis rises and height control valve 62 prevents airline 53 supplying compressed air to line 63. Height control valve 62 opens exhaust port 73 discharging the pressure in down axle suspension bag 64.
This arrangement or a closely similar arrangement is common to most trailers, which typically have two down suspension bags 64 for each axle, and usually four such bags, two for each axle. In the preferred embodiment T joint 66 in airline 63 connects airline 66 and suspension bag 64 to airline 67. Airline 67 connects to T joint 75 which connects via airline 76 to port 33 and via airline 77 to axial aperture 25 of spool valve 11. Chassis 101 is indicated by the broken line.
Airline 51 connects compressed air source 49 via T joint 74 to airlines 51 and 52. Airline 51 connects air source 49 to port 35.
Airline 52 connects compressed air source 49 to pressure regulator 54, which reduces the pressure to around 50 psi. Pressure regulator 54 has pressure gauge 55 to measure the output pressure and manual control 56 to adjust the pressure usually within 5 psi.
Airline 57 is connected through manual override valve 58 (a T
switch), which has exhaust port 60 and manual control 59 to airline 61 which connects to axial aperture 27. Manual override valve 58 may be used to reduce the pressure to atmospheric. The reduced pressure in airline 61 and thus axial aperture 27 moves spool 19 toward axial aperture 25 as shown in Fig. 1, when the pressure in airline 67 and axial aperture 25 is below 40 psi.
When the trailer is loaded height control valve 62 connects air source 49 to down axle suspension bag 64 which is at high pressure
11 ' (110 psi) and so are port 33 and axial aperture 25, which impels spool 19 to the position shown in Fig. 2. In this position spool 19 connects air source 49 through ports 33 and 32 to airline 72 to lift axle suspension bag 69, which inflates. Simultaneously exhaust port 31 is connected by spool 19 through port 34 and airline 71 to lift axle lift bag 70, which deflates lowering lift axle 68 to road contact. Thus when spool 19 is in the position shown in Fig. 2, lift axle lift bag 70 is deflated, lift axle suspension bag 69 is inflated and lift axle 68 is lowered into road contact.
When the trailer is not loaded height control valve 62 shuts off compressed airline 53 from airline 63 and connects exhaust port 73 to airline 63, down axle suspension bag 64, airline 67, and thus axial aperture 25 and port 33. The pressure in end aperture 25 falls typically to around 11 psi and spool 19 is moved by the higher pressure 50 psi in axial aperture 27 to the position shown in Fig, 1. In this position spool 19 connects exhaust port 31 to port 32 and thus to airline 72 and lift axle suspension bag 69, which deflates. Simultaneously air source 49 is connected by spool 19 to through ports 35 and 34 to airline 71 to lift axle lift bag 70 which inflates lifting lift axle 68 out off road contact.
Height control valve 62 has dump or exhaust port 83, supply or inlet port 81 receiving airline 53, air spring or outlet port 82 connected by airline 63 to T joint 66 which connects to airline 67 connecting back to port 33 and axial aperture 27 and airline 84 connecting to down axle suspension bag 64 as shown in Fig. 4.
In Fig. 5 is shown an embodiment of the invention as installed within containment box 100. Airlines 50, 67, 71 and 72 are attached respectively to fittings (ports?) 150, 167, 171 and 172 in the walls of containment box 100, which are adapted to receive airlines external to box 100. Conveniently containment box 100 is
When the trailer is not loaded height control valve 62 shuts off compressed airline 53 from airline 63 and connects exhaust port 73 to airline 63, down axle suspension bag 64, airline 67, and thus axial aperture 25 and port 33. The pressure in end aperture 25 falls typically to around 11 psi and spool 19 is moved by the higher pressure 50 psi in axial aperture 27 to the position shown in Fig, 1. In this position spool 19 connects exhaust port 31 to port 32 and thus to airline 72 and lift axle suspension bag 69, which deflates. Simultaneously air source 49 is connected by spool 19 to through ports 35 and 34 to airline 71 to lift axle lift bag 70 which inflates lifting lift axle 68 out off road contact.
Height control valve 62 has dump or exhaust port 83, supply or inlet port 81 receiving airline 53, air spring or outlet port 82 connected by airline 63 to T joint 66 which connects to airline 67 connecting back to port 33 and axial aperture 27 and airline 84 connecting to down axle suspension bag 64 as shown in Fig. 4.
In Fig. 5 is shown an embodiment of the invention as installed within containment box 100. Airlines 50, 67, 71 and 72 are attached respectively to fittings (ports?) 150, 167, 171 and 172 in the walls of containment box 100, which are adapted to receive airlines external to box 100. Conveniently containment box 100 is
12 =rectangular with sheet metal walls and a hinged door or lid, which is normally shut, for access to adjust pressure regulator 54 and manual override valve 58. The door or lid may be locked or padlocked to prevent unauthorized access.
Thus the position of lift axle 68 is automatically controlled by height control valve 62, whose height is determined by whether the trailer is loaded or unloaded.
Thus the position of lift axle 68 is automatically controlled by height control valve 62, whose height is determined by whether the trailer is loaded or unloaded.
13
Claims (9)
1. A trailer having a chassis at least one fixed axle having at least one associated fixed axle suspension air bag supporting said chassis, a lift axle having at least one associated lift air bag, and an automatic control valve for said lift axle and a source of compressed air said automatic control valve comprising a double pilot, five port spool valve with a spool said spool valve having a first pilot port at one end connected to said at least one fixed axle suspension air bag, and a second pilot port at the other end on said spool valve connected to said source of compressed air through a pressure reduction valve setting said compressed air to a reduced pressure when said trailer is unloaded the pressure in the first pilot port and the fixed axle suspension air bag is less than the reduced pressure in the second pilot port, said reduced pressure moving said spool into first normal position adjacent said first pilot port, in first normal position the spool valve connects the compressed air source to said at least one lift axle lift air bag, thus inflating said at least one lift axle lift air bag and simultaneously the spool valve connects said at least one lift axle suspension air bag to atmosphere deflating said lift axle suspension air bag, whereby said lift axle is raised when said trailer is unloaded;
when said trailer is loaded the first pilot port and the fixed axle suspension air bag are connected to the compressed air source and the pressure in the first pilot port is greater than the reduced pressure in the second pilot port, said greater pressure moving said spool into second working position adjacent said second pilot port, in second working condition the spool valve connects said at least one lift'axle lift bag to atmosphere deflating said at least one lift axle lift air bag, simultaneously the spool valve connects said at least one lift axle suspension air bag to the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered when said trailer is loaded.
when said trailer is loaded the first pilot port and the fixed axle suspension air bag are connected to the compressed air source and the pressure in the first pilot port is greater than the reduced pressure in the second pilot port, said greater pressure moving said spool into second working position adjacent said second pilot port, in second working condition the spool valve connects said at least one lift'axle lift bag to atmosphere deflating said at least one lift axle lift air bag, simultaneously the spool valve connects said at least one lift axle suspension air bag to the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered when said trailer is loaded.
2. Trailer of claim 1, said chassis having mounted thereon a height control valve having a supply port connected to said compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag, said chassis having a ride height, when said chassis is below said ride height and said trailer is loaded said height control valve connecting said supply port to said output port supplying compressed air to said at least one fixed axle suspension air bag increasing the pressure of said at least one fixed axle suspension bag, when said chassis is above said ride height and said trailer is unloaded said height control valve connecting said output port to said exhaust port lowering the pressure of said at least one fixed axle suspension air bag,
3. Trailer of claim 3, the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered the first pilot port and the fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag whereby said lift axle is lowered.
4. Trailer of claim 1 wherein said pressure reduction valve is connected to said second pilot valve through a manual exhaust valve.
5. An automatic control valve system for a lift axle for a trailer comprising a five port, double pilot port, spool valve, said system comprising a cylindrical tube containing a spool, said cylindrical tube containing a spool, and first and second end pilot ports, and five side ports, said spool being slidable in said cylindrical tube and having airtight opposed end lands and a middle airtight land separated by first and second grooves, said first groove being adjacent said first pilot port, said second groove being adjacent said second pilot port, the side ports are spaced longitudinally apart along the cylinder said first side port being connected to atmosphere, said second side port being connected to at least one lift axle suspension air bag, said third side port and said first pilot port are connected to at least one fixed axle suspension air bag, which is connected through a height control valve to a compressed air source, said fourth port being connected to at least one lift axle lift air bag, said fifth port being connected to said compressed air source said second pilot port being connected to said compressed air source through a pressure reduction valve, said spool having two positions a first normal position when said at least one fixed axle suspension air bag is at low pressure when said trailer is unloaded, and a second working position when said at least when said at least one fixed axle suspension air bag is at high pressure when said trailer is loaded, in first normal position said first groove of said spool connects said fourth and fifth side ports and said compressed air source to said lift axle lift air bag inflating said lift axle lift air bag, said second grove of said spool connects said first and second side ports and deflating said at least one lift axle suspension air bag, thus raising said lift axle, -in second normal position, said first groove of said spool connects said first and fourth side ports connecting said lift axle suspension air bag to atmosphere deflating said lift axle suspension air bag, said second groove of said spool connects said second and third side ports connecting said lift axle suspension air bag to said first pilot port and said at least one fixed axle suspension air bag, which are connected to the compressed air source, thus inflating said at least one lift axle suspension air bag.
6. System of claim 5, wherein said pressure reduction valve is connected to said second pilot port through a manual exhaust valve.
7. System of claim 5, wherein said compressed air source is connected to said at least one fixed axle suspension air bag and said third side port and said first pilot port through a height control valve.
8. System of claim 7 wherein said a height control valve has a supply port connected to said compressed air source, an exhaust port, and an output port connected to said at least one fixed axle suspension air bag, said height control valve being mounted on a chassis having a ride height, when said chassis is below said ride height and said trailer is loaded said height control valve connecting said supply port to said output port supplying compressed air to said at least one fixed axle suspension air bag increasing the pressure of said at least one fixed axle suspension bag, when said chassis is above said ride height and said trailer is unloaded said height control valve connecting said output port to said exhaust port lowering the pressure of said at least one fixed axle suspension air bag,
9. Sytem of claim 8 wherein said height control valve has a level arm pivotally connected at the end remote from the valve to an upright rod, which is pivotally connected at it's lower end to a fixed axle, said lever arm actuating the connection of said output port to said exhaust port when said chassis is above said ride height when the trailer is unloaded, said lever arm actuating the connection of said supply port to said output port when said chassis is below said ride height when the trailer is loaded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2818422A CA2818422A1 (en) | 2013-06-18 | 2013-06-18 | Automatic lift axle control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2818422A CA2818422A1 (en) | 2013-06-18 | 2013-06-18 | Automatic lift axle control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2818422A1 true CA2818422A1 (en) | 2014-12-18 |
Family
ID=52105634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2818422A Abandoned CA2818422A1 (en) | 2013-06-18 | 2013-06-18 | Automatic lift axle control system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2818422A1 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016210099A1 (en) * | 2015-06-23 | 2016-12-29 | Polar Tank Trailer, Llc | Automatically deploying lift axle control system |
| US9776677B2 (en) | 2016-02-10 | 2017-10-03 | Kelly W YAKIMISHYN | Lift axle suspension |
| US10160278B2 (en) | 2014-12-16 | 2018-12-25 | Aktv8 LLC | System and method for vehicle stabilization |
| US10259284B2 (en) | 2014-12-16 | 2019-04-16 | Aktv8 LLC | Electronically controlled vehicle suspension system and method of manufacture |
| US10315469B2 (en) | 2016-09-06 | 2019-06-11 | Aktv8 LLC | Tire management system and method |
| US10675936B2 (en) | 2014-12-16 | 2020-06-09 | Atv8 Llc | System and method for vehicle stabilization |
| US10870325B2 (en) | 2014-12-16 | 2020-12-22 | Aktv8 LLC | System and method for vehicle stabilization |
-
2013
- 2013-06-18 CA CA2818422A patent/CA2818422A1/en not_active Abandoned
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10160278B2 (en) | 2014-12-16 | 2018-12-25 | Aktv8 LLC | System and method for vehicle stabilization |
| US10259284B2 (en) | 2014-12-16 | 2019-04-16 | Aktv8 LLC | Electronically controlled vehicle suspension system and method of manufacture |
| US10675936B2 (en) | 2014-12-16 | 2020-06-09 | Atv8 Llc | System and method for vehicle stabilization |
| US10870325B2 (en) | 2014-12-16 | 2020-12-22 | Aktv8 LLC | System and method for vehicle stabilization |
| US10882374B2 (en) | 2014-12-16 | 2021-01-05 | Aktv 8 Llc | Electronically controlled vehicle suspension system and method of manufacture |
| WO2016210099A1 (en) * | 2015-06-23 | 2016-12-29 | Polar Tank Trailer, Llc | Automatically deploying lift axle control system |
| US10099529B2 (en) | 2015-06-23 | 2018-10-16 | Polar Tank Trailer, Llc | Automatically deploying lift axle control system |
| US9776677B2 (en) | 2016-02-10 | 2017-10-03 | Kelly W YAKIMISHYN | Lift axle suspension |
| US10315469B2 (en) | 2016-09-06 | 2019-06-11 | Aktv8 LLC | Tire management system and method |
| US10688836B2 (en) | 2016-09-06 | 2020-06-23 | Aktv8 LLC | Tire management system and method |
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