CA2499892A1 - A vehicle restrictor for the impedance of vehicle movement - Google Patents

Abstract

The fluid-filled retractable vehicle restrictor can be used where it is impractical to use a traditional speed bump, for improved traffic management and the prevention of vehicular collisions. The invention uses fluid to control the height of a retractable restriction surface in order to vary vehicle impedance. The fluid also distributes the vehicle's loading forces to static structural components rather than mechanical moving parts. Reduced stress within fewer moving components minimizes maintenance. Unlike prior art, an internal fluid transfer mechanism allows the height of the restriction surface to be set independently of the vehicle's presence. Maintaining a specific geometrical shape of the restriction surface during tire traversal gives the invention another parameter of vehicle impedance because various restriction surface shapes can harden or soften the impact to the vehicle's tires. The invention also warns an approaching vehicle operator of activated impedance through visible or illuminative indicators.

Description

2 PCT/US2003/029711 TITLE OF INVENTION
A VEHICLE RESTRICTOR FOR THE IMPEDANCE OF VEHICLE MOVEMENT
TECHNICAL FIELD
This document describes the conceptual design of a Vehicle Restrictor (speed bump), a device intended to restrict the position and speed of automotive vehicles.

A Vehicle Restrictor provides the same function as a traditional speed bump but is capable of variable height activation relative to the surface of the road.
Consequently the motorist will receive a tactile feedback through the vehicle's tires and suspension system that varies from a maximum restriction to no restriction. Thus a Vehicle Restrictor can be used in a traffic environment in which it is impractical to use a traditional speed bump. When integrated with an appropriate traffic management system, the Vehicle Restrictor can be used to impede the position and speed of vehicles for improved traffic management and the prevention of vehicular collisions involving pedestrians, trains, and other vehicles. Such a tactile feedback serves to both remind the operator of the traffic laws as well as to provide restraint from doing otherwise. The activation of a Vehicle Restrictor can also improve motorist reaction time by providing forewarning of an otherwise imminent collision. The present invention provides a more flexible degree of impedance control and a design requiring less maintenance than other related retractable devices.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1A is a front cross-sectional view of the inactive Vehicle Restrictor Figure 1 B is a side cross-sectional view of the inactive Vehicle Restrictor Figure 1C is a front cross-sectional view of the active Vehicle Restrictor Figure 1 D is a side cross-sectional view of the active Vehicle Restrictor Figure 2A shows an overhead view of the Vehicle Restrictor opening at the street surface Figure 2B shows the layers of the Restrictor Surface in the primary embodiment Figure 3 are examples of how various Restriction Surface 8 shapes vary the type of vehicle impedance Figure 4A and 4B shows ground level and overhead views of Restriction Surtaces 8 without tapered ends to demonstrate the comparative affect on the tire and steering.

Figure 4C and 4D shows ground level and overhead views of Restriction Surfaces 8 with tapered ends to demonstrate the comparative affect on the tire and steering.
BACKGROUND ART
Related inventions are by Dunne (US 3,389,677), Thompson (US 5,509,753), and Harvey (GB 2333114 A). Prior art relies significantly on bearing, levers, rollers, and other such components. This is particularly an issue since the components will be located below the street surtace, making maintenance difficult. So what is needed is a system that uses fewer of the componenfis that are subject to mechanical wearing. The redistribution of stresses to lessen the forces on the existing components will also provide longer operating life.
These expected advantages are obtainable because the present invention uses fluid to actuate a surface for impeding the vehicle and transmit the impact of the vehicle's weight forces to the ground.
Other designs of prior art also suggests fluid as a part of the operation in impeding vehicles, such as patents by Barbar (US 4,362,424), Mareau (EP 370154 A1), Reid (GB 2328235 A), Heeks (WCd 9840563 A1 ), Kamienchick (US 6,024,510), and Beveridge (GB
2288419 A).
Generally with these inventions, the vehicle's weight is used to compress the fluid contained beneath a flexible top covering that makes contact with the vehicle's tires.
Various flow control devices (pipes, tubes, chambers, valves) are configured to allow the pressurized fluid to escape, but to do so while offering a degree of hardness to the tires as those tires cross over the surface.
The parameters of the flow control devices are fixed and thus the prior art speed bump is designed for a specific speed limit. This overall design strategy does not offer the capabilities of the proposed invention.
The proposed invention uses fluid to position an impedance surface to the vehicle's tires but the design strategy is to set and generally maintain the height of that impedance surface as opposed to setting a degree of surface hardness using pressurized, escaping fluid. The setting of the impedance height can be very specifically set within the range from full impedance to no impedance. The means to position the contact surface is inherent to the system. This means that the vehicle's tires and weight are not required in order to actuate the system.
By the nature of its design, prior art has no true inactive condition because it can not be deactivated to offer no impedance. An inactive condition is defined as having an ability to nat exert vehicle impedance, regardless of the vehicle's speed. Essentially the prior art restriction surface can not be removed from making contact with the vehicle's tires. Prior art has no true inactive condition because its very design uses the tires of vehicles travelling at typical driving speeds to ensure that impedance is presented. If the prior art systems are installed in a roadway then vehicles travelling at the speed limit will be unnecessarily slowed or stopped, thus having a negative affect on traffic flow. As another example, imagine the adverse affect that the prior art systems will have on an emergency vehicle (police, fire, and ambulance) traveling at high speed because those systems lack the ability to offer no impedance to vehicles moving at or above the speed limit.
The inconsistency in setting the hardness of the prior art restriction surface results from the inconsistent input of each vehicle that traverses the prior art system.
The vehicle factors that will affect hardness and that will vary with virtually every vehicle include:
Vehicle weight, tire diameter, tire width, tire pressure, vehicle speed, angle of the tires upon impact with the restriction surface, and the length between the vehicle's front and rear axles. The consistency of system operation to impede a small car and a heavy truck, both traveling at the same speed, is likely to be unpredictable and result in significantly different levels of impedance because of so many vehicle factors. By contrast, a more effective system should offer reasonably the same degree of impedance to both vehicles. The proposed system positions the restriction surface height, with the design capability to generally maintain that height as the vehicle passes over the surface. Thus more predictable results are achieved from vehicle to vehicle since a certain impedance height is more exact and absolute than a degree of hardness resulting from the multiplicity of vehicle factors mentioned.
Consider the effectiveness of prior art in attempting to impede both the front and rear tires.
With prior art, after the passing of the front tires a recharge time is required to re-pressurize the restriction surface to its initial height. The recharge requirements will not likely allow the system to return the speed bump to a volume of effectiveness after the passing of the front tires and before the contact with the rear tires. Consequently, the rear tires will consistently receive less impedance than the front tires. Less effective impedance will result because motorists will know that they need only brake for just the front tires in their effort to reduce the impact to their vehicle. Since the proposed invention operates on the principle of using fluid to set and generally maintain the height of the restriction surface, the rear tires will receive the same degree of impedance as the front tires. This provides more effective impedance than the prior art systems because the motorist will have to brake for both the front and rear tires.
Setting variable baseline impedances is not obtainable by prior art as it is with the proposed invention. If prior art is intended for a roadway with a 45 mph speed limit then the design [fluid hardware p2~ameters (areas, volumes, tube diameters, number of tubes, etc.) and components (flow rate devices, tubes, cylinders, directional valves, auxiliary chambers)] are fixed for that specific threshold speed. If special conditions (traffic congestion, the timing of school zone activation, wet road, lower visibility due to fog, other) demand that the speed limit be temporarily lowered to ensure safety, prior art can not adjust its fixed design structure to change the threshold speed to the lower baseline level. Since the proposed invention can not only vary the restriction surface height, from some minimum (including zero) to some maximum, that height can be adjusted to be suitable for the changed traffic condition and the lower speed limit and later returned to the height consistent with the nominal speed limit. It is the independent setting of a

3 restriction surtace height instead of the vehicle dependent setting of a restriction surface hardness that allows more precise control of the restriction surface and a more direct communication with the motorist regarding special road cautions or temporary changes in the safest baseline speed limit.
Beyond the primary structural design differences, there are other advantages of the proposed invention over prior art. Prior art does not suggests a controller to be responsive to a traffic management system having the purpose to vary system operational parameters to control vehicle movement to maintain safety or compliance with traffic rules.
Furthermore, prior art requires that the restriction surface be flexible (conform its shape under the load of the tire) so as to not maintain surface integrity. Therefore, prior art would not intend to invoke a degree of impedance just from the specific shape of the restriction surface. However, maintaining the integrity of a specific geometrical shape of the restriction surface during tire traversal gives the proposed invention another parameter of impedance. Certain restriction surtace shapes determine haw the tires will traverse across, having the effect to harden or soften the impact to the vehicle.
MODES FOR CARRYING OUT THE INVENTION
The Vehicle Restrictor is generally positioned transverse to the roadway. It is installed in a recessed region below the street surtace. The objective is to provide a Vehicle Restrictor design that is simple, requires less maintenance due to the fewer mechanical components and the redistribution of forces from movable mechanical components to static structural components. It is also desirable to provide vehicle impedance that is variable in the degree of operation. This provides the motorist with better interactivity and feedback regarding the urgency of the traffic environment. For example, an otherwise impending collision involving the vehicle to be impeded would require faster activation of the Vehicle Restrictor to capture the driver's attention to invoke more aggressive slowing of the vehicle. The present invention is intended to be responsive to the commands from a traffic management system that monitors a traffic environment.
Upon receiving commands from such a traffic management system the system employs the following operation.
The primary embodiment is shown in Figures 1A -1 D. System operation focuses on the transfer of fluid between a reservoir volume 1a and an active volume 1b. An insufficient amount of fluid in the active volume 1b corresponds to a system that is inactive in providing vehicle impedance. In the primary embodiment the fluid is transferred to the active volume 1 b by decreasing the dimensions of the reservoir volume 1a, basically squeezing the fluid. An Actuator 2 presses a rigid object (Plunger 3) against a leak-resistant membrane (Bladder

4) containing the fluid 1. Bladder Reinforcement 5 is provided to the Bladder 4 throughout the system to prevent its bulging as the fluid 1 is pressurized and transferred. The system transfers fluid 1 from a reservoir volume 1a into an active volume 1b bounded on the top by the Cap 6 and on the bottom by the Support Frame 1. The bottom of Support Frame 7 is held static against the ground but the Cap 6 is elevated as fluid 1 is transferred into the active volume 1b to position the attached Restriction Surface 8 above street level and create impedance to the movement of vehicles.
Varying the height of activation is accomplished by varying the volume of fluid 1 transferred from the reservoir volume 1a to the active volume 1b.
Maintaining fluid 1 in the active volume 1 b to support the Restriction Surface 8 during vehicle loading distributes the loading more uniformly than with a system that has discrete mechanical loading points. The uniform support keeps the load balanced to prevent the shifting of components, uneven mechanical wear, and reduced component life. As the vehicle makes contact with the Restriction Surface 8, the topside of the attached Cap 6 pressurizes the fluid 1 because of the vehicle's weight. That fluid pressure is distributed to the inner surfaces of the Cap 6 as well as the top of the Support Frame 7. The Support Frame 7 transfers some of the forces to the ground.
The overall result is that the forces resulting from the vehicle's weight are distributed primarily to structural components rather than to moving components that are subject to wear (mechanical pins, gears, levers, rollers, etc).
As the Actuator 2 withdraws the Plunger 3, the reservoir volume 1a increases and allows the fluid 1 in the active volume 1 b to return to the reservoir volume 1 a.
This allows the elevation of the Cap 6 and the attached Restriction Surtace 8 to return below the street surface level, thus removing vehicle impedance.
The Actuator 2 provides the extension and retraction of the Plunger 3 according to the commands from the Controller 12. The Actuator 2 is of well-known technology such as a hydraulic cylinder, pneumatic cylinder, or motorized jackscrew. The technology is not particular provided that it can provide the controlled force to transfer the fluid 1 into the active volume 1 b. The motorized jackscrew is the preferred component because of maintenance and energy consumption advantages. The motorized jackscrew requires fewer components and will require less maintenance than the hydraulic or pneumatic systems. This is especially an issue considering the system will be stored below the street level and frequent maintenance would be too disruptive to trafFc. After the motorized jackscrew is positioned during a particular actuation it will hold its position without expending additional energy. This allows the volume of fluid 1 displaced by the Plunger 3 to be maintained as the vehicle's weight is applied to the Restriction Surtace 8.
An alternate embodiment to transfer fluid 1 between the reservoir volume 1a and the acfiive volume 1b is to use pumping systems, which are of commonly known technology. The Actuator 2 and Plunger 3 are part of the preferred embodiment because less maintenance is required.
The Plunger 3 is part of the fluid transfer system in the primary embodiment and is used in conjunction with the Actuator 2 to reduce the reservoir volume 1a. A rigid material is most desirable because of the compressive forces required for squeezing the fluid 1. A specific shape for the Plunger 3 is not required, However a spherical surface is more efficient because a sphere

5 provides a large surface area for its geometry. Thus the amount of fluid 1 that can be displaced for a given movement of the Plunger 3 is greater with a spherical shape.
The proposed invention relies on the placement of fluid 1 to actuate the system and to transmit the vehicle's impact and weight-bearing forces. In general a fluid would be a substance (such as a liquid, gas or gel) capable of flowing or conforming to the outline of its container. It is preferred that the fluid 1 be incompressible so that the desired positioning of the Restriction Surface 8 above the street surface is not reduced by fluid compression.
Except for one or more ports for the entry and exit of fluid 1, the Bladder 4 will be enclosed to constrain the fluid 1. This flexible, leak-resistant membrane is employed within and between the reservoir volume 1a and the active volume 1b, the walls of which (Bladder Reinforcement 5) will protect the Bladder 4 from puncture, abrasion, and bulging. In an alternate embodiment friction seals similar to piston rings could be used instead of a Bladder 4 to contain the fluid 1 between moving parts in the reservoir volume 1a and the active volume 1b. However, the Bladder 4 is preferred because of better reliability against fluid leakage and less friction wear.
The Cap 6 encloses the fluid 1 between its inner surfaces and the top of Support Frame 7 to comprise the active volume 1 b. Its displacement from the Support Frame 7 depends on the amount of fluid 1 in the active volume 1b. Its top outer surface supports the Restriction Surface 8.
Another embodiment of the same invention would make the Cap 6 and the Restriction Surface 8 the same physical part. The inside lateral surfaces of the Cap 6 can be used to support the lateral fluid 1 pressure within the active volume 1b.
The top of the Support Frame 7 fits within the open side of the Cap 6, to support the underside of the contained fluid 1 within the active volume 1 b as shown in Figures 1A -1 D. When the fluid pressure increases due to the impact and loading forces from the vehicle, the Support Prame 7 transmits the forces to the ground through its axial support along its length.
To reduce maintenance, actuation components could be sealed from contaminants resulting from exposure to the traffic environment and the weather. A seal placed between components that are intended to move relative to each other should be flexible as well as reduce the entry of dirt, gravel, and moisture. A Cap Seal 9 could be placed between the perimeters of the Cap 6 and the Support Frame 7 as shown in Figures 1A -1 D. Figure 1C -1 D
shows how the flexibility of the Cap Seal 9 will still allow the Cap 6 and the Support Frame 7 to move relative to each during system activation, while keeping contaminants out of the opening between the two.
The Bladder Reinforcement 5 in the Plunger 3 area could be extended to provide an enclosed seal for the Actuator 2. An example of this is a channeled box or cylinder enclosing the Actuator 2 / Plunger 3 or other fluid transfer means.

6 The Restriction Surface 8 is mounted on top to the Cap 6 and is the component of the Vehicle Restrictor that makes contact with the vehicle's tires. Its shape is expected to have an effect on the nature of the impact to the vehicle's suspension system.
Consider the following examples. Both the initial and ending tire positions shown in Fig. 3A will provide impact to the vehicle. The leading edge of the Restriction Surtace 8 provides a first impact as the tire makes contact. The falling edge allows the tire to directly strike the street surface, thus providing a second impact. In Fig. 3B the initial impact is lessened at the initial position with the absence of an abrupt surface change as the tire traverses the surface. However, the falling edge allows the vehicle to directly strike the street surface, providing the most significant impact for this particular shape. In Fig. 3C, the initial impact is similar to that in Fig. 3A but is lessened on the falling edge because of the presence of surtace material to lower the position of the tire before it strikes the street surface. Various combinations of shapes for the leading and falling edges can be combined to obtain the desired total impact effect.
As shown in Fig. 2B, in the primary embodiment the Restriction Surface 8 is a combination of components providing the basic surface shape, the Wear Indicator 8d, and the Wear Covering 8c. The Wear Indicator 8d and Wear Covering 8c address maintenance issues due to abrasion from the tires. Another embodiment of the invention may not address such maintenance issues and simply provide a component for making contact with the tires to offer impedance.
Figure 2B shows that the Wear Covering 8c fits on or over the Restriction Surtace Shape 8b to make contact with the vehicle's tires. The abrasion from the tires eventually causes the Wear Covering 8c to require replacement. The use of a replaceable Wear Covering 8c over the Restriction Surface Shape 8b allows rapid and inexpensive maintenance without degradation of the Restriction Surtace Shape 8b. The Wear Covering 8c material should be abrasion resistant without being unduly harsh on the wearing of tires. The Wear Indicator 8d reveals when the Wear Covering 8c is due for replacement. An example of a Wear Indicator 8d is a colored layer beneath the Wear Covering 8c surface that becomes exposed arad visible only after erosion has occurred through the Wear Covering 8c. At that time the Wear Covering 8c is due for replacement.
Contact between the Restriction Surtace 8 and the tire should be predominantly confined to the tire's outer rim surtace, the portion that contacts the road. Contact with the sides of tire should be minimized. To accomplish these constraints the ends of the Restriction Surface 8 may ~5 require a different cross-section than the middle portions. Figure 4A shows the ground level view and Figure 4B shows the overhead view of the tire as it passes the right end of the Restriction Surface 8 without a tapered end. Fig. 4B implies that if the inside of the tire wall makes significant contact with the abrupt outer edge of the Restriction Surface 8 with a significant deployment height during a slight angle of the tire, then disruption to the steering of the vehicle may result. This is not the same type of disruption to vehicle movement that results from maintaining contact with the tire's outer rim surface and elevating the tire to invoke the suspension

7 system as show in Figures 3A through 3C. The vehicle restriction means described in this invention seeks the latter approach by also using the concept of tapered ends as shown in the ground level view of Figure 4C and the overhead view of Figure 4D. These views show that as the tire approaches the end of the Restriction Surface 8 at the same angle as before, contact is maintained with the tire's outer rim surface, thus preventing the previously described possible disruption to steering. The contour of the tapered end can be made moderate enough to maintain sufficient contact with the outer rim surface of the tire.
Figure 2A shows that Warning Indicators 13 (the illumination of lights or reflective or colorful markings) placed in proximity to the Vehicle Restrictor opening at the street level will capture the motorist's attention and warn of system activation or presence.
Such a warning system may place the Warning Indicators 13 on the Restriction Surface 8, to be visible as the surface is active. Warning Indicators 13 may also be placed on the street surface such as on or around the Street Frame 11. The idea is to notify the motorist in advance of reaching the Vehicle Restrictor so that sufficient time is given to slowing the vehicle down.
The Street Frame 10 in Figure 1B, 1D, and 2A maintains a defined opening for raising and lowering of the Restriction Surface 8 and the Cap (not shown but positioned below the Restriction Surtace 8. Otherwise, erosion of the road materials might interfere with system operation or continually degrade the integrity of the street surface surrounding the opening. A material such as angled steel may serve as an adequate Street Frame 10.
The Street Frame Seal 11 shown in Figures 2A,1 B and 1 D is installed between the top of the cap and the Street Frame 10. It is installed around the street surface opening to reduce debris from entering the recessed area where the system is installed. Since it is the first line of defense against contaminants it should not only be flexible but also be toughen against puncturing or abrasion. Figure 1B and 1D shows how the Street Frame Seal 11 will reduce the presence of debris from contaminating the system.
The Controller 12 will convert command signals from an external traffic management system to the appropriate vehicle impedance. The activation and deactivation response times of the Vehicle Restrictor may need to be varied depending on the speed and or distance of a particular vehicle to be restricted. The degree of the motorists' compliance with the trafFc laws and safety intent within an environment using vehicle restriction may place a greater or lesser demand on the Vehicle Restrictor. Thus for the most enhanced operation, the Controller 12 should be capable of providing proportional deployment height and variable speed responses of the Restriction Surface 8 relative to the traffic management system's command signals. This can be accomplished with servo controller or similar well-known technology to compare and or adjust the movement of the actuation components relative to the command from the trafFc management system.

8 An alternate embodiment of this invention is to configure the actuation components so that a restriction surface below the street surface is presented to the vehicle's tire. This negative activation (as opposed to the positive activation previously described) would resemble a recessed area across a lane of traffic with a retractable door or surface that varies the depth that the tire drops below the street surface. In an inactive position, the restriction surface is generally level with the street surface, as supported by a fluid-filled volume. However, upon activation the physical support of the top surface would be lessened by extracting fluid from the supporting fluid-filled volume to allow the surface to convex and present a certain cavity depth to the tire, much like a controllable depth pot-hole.
It is to be understood that the present invention is not limited to any of the embodiment described above, but encompasses any and all embodiments within the scope of the following claims.

9

Claims (18)

What I claim as my invention is:

1. A vehicle restrictor system for the impedance and control of vehicle movement, said system comprising:
a surface to provide an impact to the vehicle's suspension system resulting from the contact between said surface and the vehicle's tires;
a first volume of fluid capable of setting and generally maintaining a degree of height impedance by supporting said surface;
a second volume of fluid in communication with said first volume of fluid, wherein said second volume of fluid acts as a reservoir to said first volume of fluid;
an inherent fluid transfer means by which the setting of a degree of height impedance of said surface by said first volume of fluid can be varied through fluid transfer with said second volume of fluid, independent of the vehicle; and one or more components to support and confine said volumes of fluid;

2. The system according to claim 1, wherein the fluid transfer means further comprises:
a) at least one actuator, b) a leak-resistant means for containing said fluid, c) a means for reinforcing said leak-resistant means, and d) at least one rigid surface positioned by said actuator whereby, a corresponding amount of fluid is displaced.

3. The system according to claim 1, wherein said fluid transfer means is a pump, wherein said fluid is pumped into a volume whereby said restriction surface is activated or deactivated.

4. The system according to claim 1, further comprising a controller responsive to external traffic commands, to govern the rate and amount of fluid transferred whereby the degree of height and activation speed of the restriction surface is controlled.

5. The system according to claim 4, wherein said controller allows activation of said restriction surface in a variable degree of operation, such that the speed and / or height of the said restriction surface can be varied.

6. The system according to claim1, wherein said support component is directly or indirectly in contact with a ground surface such that the forces resulting from the vehicle's contact with said restriction surface are transmitted by said fluid to the ground surface.

7. The system according to claim 1, wherein some portion of said restriction surface is tapered to maintain predominant contact with the outer rim surface of the tire.

8. The system according to claim 1, wherein said restriction surface has a specific predetermined geometrical shape to invoke a specific type of vehicle impedance.

9. The system according to claim 1, further comprising a covering surface dimensioned to fit over or on said restriction surface to provide resistance to wear or modular maintenance.

10. The system according to claim 9, further comprising a means for indicating the extent of wear associated with said covering.

11. The system according to claim 1, further comprising at least one seal carried in close proximity to system components to provide resistance to the penetration of contaminants.

12. The system according to claim 1, further comprising illuminative indications of the vehicle restrictor's presence or operation.

13. A method for impeding and controlling vehicle movement comprising the steps of:
a) transferring a confined fluid between a reservoir condition and an active condition via a transfer means wherein said transfer is independent of contact with a vehicle ;
b) actuating a restriction surface, wherein said restriction surface is in communication with said fluid to offer impedance to the tires of a vehicle.

14. A method of warning an approaching vehicle operator of an activated impedance, comprising the step of:
a) activating a restriction surface wherein a means for warning is visible by the vehicle operator prior to vehicle contact.

15. The method of claim 14, wherein said means for warning is at least one illuminative indicator.

16. The method of claim 14, wherein said means for warning is at least one indicia.

17. The method of claim 15, wherein said illuminative indicator is a light.

18. The system according to claim 1, wherein said degree of height is measured positively or negatively from a predetermined reference.