GB2342944A - Vehicle control unit allowing passage one way only - Google Patents

Abstract

A powered traffic control unit comprises a base 15, traffic control means 20 pivotally mounted on the base, and drive means 14 for moving the traffic control means 20 from a first operative position to a second inoperative position. The control means may be a plate or one or more teeth or fingers which can be locked in the first operative position. Electronic control means can distinguish between end of travel and collision with an obstruction. In the event of the latter, the movement is automatically reversed for a short distance before stopping. The unit may be operated remotely.

Description

Traffic Control Unit Traffic control units are well known devices which are used to permit a vehicle to pass in one direction but prevent vehicles passing in the opposite direction.

Conventionally, traffic control units comprise a pivoted flow plate that extends above the road surface at an angle, the plate being biased so that it either maintains its extended position or returns to its extended position if moved. In one direction, the plate is free to pivot thus allowing a vehicle to pass over it, but in the other direction, the plate is prevented from pivoting and thus forms a barrier to movement against the wheel of the vehicle.

These types of device are well known and used, but, because they only allow traffic to flow in one direction, at least two access points are required to any area controlled by such devices, one for entrance and one for exit. In many situations, this is not possible or practical and therefore these types of unit cannot be used.

The present invention is a traffic control unit comprising a base, traffic flow control means pivotally mounted on the base, and drive means for moving the traffic control means from a first operative position to a second inoperative position.

The traffic flow unit may include a cover which may carry insignia, reflective material or similar, and the flow control means, which may be a plate or arrangement of teeth or fingers, is preferably pivotally connected to the base.

The drive means preferably comprises an electric motor and appropriate gearing, for example a rotating pinion that co-operates with a spur gear train. Power for the electric motor is preferably provided by means of an electric battery, though other suitable forms of power supply may be employed, for example, mains electricity or solar power. Further, there is provided electronic control means for controlling the operation of the drive means.

In a preferred embodiment the electronic control means is able determine the position of the flow control mechanism relative to the base plate. The electronic control means preferably determines position and movement of the flow control mechanism by monitoring the current drawn by the drive means, although other embodiments are possible which employ photo-detectors, micro-switches, timers or any other suitable means. As such, the electronic control means is able to determine when the flow control means reaches its limit of travel with respect to the base and also if, for any reason, movement of the barrier is restricted during operation.

Preferably, the electronic control means is arranged to distinguish between end of travel and collision with an obstruction, and in the event of the latter, automatically to reverse movement of the traffic control means for a short distance before stopping.

The limit of travel of the traffic control means may be set by the provision of suitable resilient end stops.

The electronic control means preferably also includes means to enable the traffic control means to be controlled by a user. This is preferably effected by means of a radio receiver adapted to receive a predetermined coded radio signal from an associated transmitter. Other suitable means may however be employed, for example, a remotely sited switch or sensor or other transmitter receiver combinations.

A radio receiver in the unit may monitor either continuously or for pre-determined timed intervals for transmissions, and on receipt of a valid code operates the mechanism to either raise or lower the flow control means.

Power for operation of the unit is provided by internal primary batteries. Through the use of a radio receiver that is powered on to listen for transmissions for a fraction of each second, the battery life is significantly increased.

Until a valid signal is received, all other circuits are kept in a very low power sleep mode which reduces battery drain even further.

By operating in this power save mode battery life can be extended to over three years.

In the event of a failure of remote operation of the unit (for example because of discharged batteries or through malfunction), provision is made for manual operation by the use of a specially adapted tool that allows access to the drive means such that it can be manually operated.

The unit is modular comprising a drive module and at least one traffic control unit. By adding further traffic control units, the width of flow control can be increased to suit different applications. The cover for the unit is removable with the correct tool which allows for maintenence or the replacement of damaged parts if necessary.

The present invention affords a number of advantages over existing traffic control units. As the unit is powered, it can be operated to allow vehicle movement in both directions, therefore it becomes a low cost access control device. The additional advantage it has over access control devices is that it allows visitors to enter the restricted area without supervision, but, as the unit cannot be operated by other than authorised users, prevents exit and thus deters un-authorised parking. Bona fide visitors, having completed their visit are allowed to exit by activating the control. The activation may be by a staff member or automatically upon presentation of the appropriate authorisation, e. g., coin/token, smart card, rf id, bar-coded receipt, or the like..

This is particularly beneficial to disabled groups who at present cannot always rely on motorists to keep disabled parking areas for proper use. By placing this unit at the access point to a disabled parking area, unofficial users can be deterred from abusing the system, authorised users are allowed to exit when proof of authorisation is verified.

As the unit is capable of operating from batteries, then installation is less costly than for normal barriers which require mains electricity.

As the unit can be surface mounted as well as sub-surface mounted, then the shape of the housing also acts as a speed control device thereby slowing vehicles entering a parking area and thus providing an additional traffic calming effect.

If sensors are used to detect vehicles waiting, then this can be configured to allow vehicles to pass after a set time which is long enough to cause frustration but short enough not to prevent the likes of postal vans, deliveries etc. to be unduly delayed. In this manner, entire streets can be cordoned off so that convenient use is only afforded to residents. Times can be set differently according to the time of day i. e. a longer delay would be set at peak traffic times, a shorter one at others to lessen the effect on legitimate users when there is less likelihood of pass through traffic.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a vertical cross section through the front elevation of a traffic control unit, with some details omitted for clarity; Figure 2 shows in more detail the motor and gear arrangement of a traffic control unit; and Figure 3 is a circuit diagram for the control circuitry of a traffic control unit.

Referring to Figures 1 and 2, a traffic control unit comprises essentially two parts, a drive module and a traffic control module. By adding additional traffic control modules the length of the traffic control module can be adjusted to suit the width of the road or opening being controlled.

The drive module has a rigid base plate 1 which has a flat base that can be secured in holes drilled into a suitably strong ground structure by conventional anchor bolts (not illustrated) with no need for excavation. Secured to the base plate 1 are two side members 2 each having accurately machined holes to accept bearings 3 and bushes 4. The bearings 3 support a main drive shaft 5 on which is mounted a gear 6. The gear 6 is driven by a gear 7 which is mounted on a shaft 8 and driven by a gear 9 which is mounted on the same shaft as a gear 10. The gear 10 is driven by a pinion 13 on the output shaft of a gearbox 12 whose input is driven by a motor 11.

The drive module is protected by a cover 14.

The traffic control module has a rigid base 15 that can be secured in holes drilled into a suitably strong ground structure by conventional anchor bolts (not illustrated) with no excavation. Secured to the base plate 15 are two side members 16 each having accurately machined holes to accept bushes 17. These bushes 17 support a second shaft 18 which is attached to the main drive shaft 5 through a coupling 19.

Mounted on the shaft 18 at set intervals, are traffic control fingers 20 which are normally free to rotate on the shaft and are biased to an upright position by a counterweight. Thus, the fingers 20 provide an obstacle to vehicle access in a forward direction. However, when access in the reverse direction is required, the drive module is activated to cause the shaft 5 and hence the shaft 18 to rotate and cause pins 21 which are attached to shaft 18, to engage a lug on each finger 20 and rotate the finger into the down position. When the finger reaches the end of its travel, it comes into contact with the base 15 causing the drive motor 11 to stall.

The substantial increase in the current drawn by the motor at stall is sensed by control circuitry to determine end of travel and so to discontinue drive current to the motor.

Sensing end of travel in this way mitigates the need for sensors such as micro-switches or photo-cells, any of which would be prone to unreliability in the harsh road-level operating environment. This current sensing process also provides a safety over-ride in the event that the fingers come into contact with an obstruction before they reach the normal end of travel.

To protect the module, a cover 22 of rigid construction containing slots for the fingers is secured to the base 15 by tamper-proof bolts.

To extend the effective cover length of the traffic control unit, additional traffic control modules can be attached and coupled to the shaft through a coupling 23, a rubber extrusion 24 providing a seal between the modules to protect against the ingress of water and contaminates such as dirt.

The coupling 23 can also be used to attach a manual override device in the event of a failure in the power or drive system.

Electronic circuitry, which can be housed within the traffic control module or in a separate dedicated housing, controls and sequences the automatic phase of operation.

Starting with the fingers in the upright position, once a valid signal has been received from a remote control, power is applied to the motor in the correct polarity to lower the fingers until the end of travel of the fingers is detected.

Upon detection of end of travel, power is removed and the sequence halted. Once the vehicle has passed over unit a control signal, sent from an appropriate sensing device or from the remote control, causes power to be applied to the motor in the correct polarity to reverse the shaft and hence let the fingers rise to the upright position due to the bias of the counter-weight built into the shape of the finger. As an extra precaution, an additional lug can be included such that the fingers can be driven back into the upright position.

This additional may also form the basis of a locking means arranged to lock the fingers or other flow control means into a desired position with respect to the base plate. In one configuration, for example, the base plate is mounted onto a road surface and the flow control means is moved between substantially upright and horizontal positions by the passage of a vehicle over the unit. Once the vehicle has passed over the unit and the flow control means has returned to the substantially upright position, it is then desirable to lock the flow control means so that it cannot be moved.

If vehicle movement is prevented in the previous direction of travel, then by locking the flow control means, the vehicle is prevented from travelling in the other direction and the unit becomes an effective anti-theft device.

In an alternative embodiment, electronic timers, microswitches and/or tilt switches may be used to identify that the fingers have reached the end of their travel.

Power for all operations of the traffic control unit is obtained from a set of standard batteries which can be contained within the unit or in a separate housing. Current drain from the batteries is caused by two loads, namely standby power to a radio receiver, and drive power to the motor and control circuits. Although the drive power represents a heavy load it is only required in short occasional bursts and the greater drain on the battery over its operating life is the standby power. This drain is minimised by switching the receiver on for a short period to monitor for an appropriate signal and then to switch it back off again if no signal is present. By using this technique, power savings of over 99% can be achieved with little recognisable effect to the user and battery life of two to three years can be obtained from a single set of standard D alkaline batteries.

In an alternative power supply arrangement, photocells may be used to provide continuous standby power for the radio receiver, substanially extending battery life. If photoelectric cells are used in conjunction with re-chargeable batteries, then battery replacement can be virtually eliminated.

In an alternative power supply arrangement, a mains derived supply can be used which will eliminate the need for batteries as a primary source, batteries only being required as back-up in the event of a mains power failure.

A hand operated wireless remote control is provided for the user. Operation of a button on the control gives out a radio signal in one of the licence-exempt bands reserved for such applications. Each traffic control unit is provided with its own unique code to prevent spurious operation of any neighbouring units.

In the event that the mechanism fails to operate for any reason, means is provided for the user to lower the fingers manually if they are in the upright position. Having removed the cover from the end of the traffic control module remote from the drive module, the shaft 18 can be rotated by inserting an appropriately shaped crank engaging the exposed coupling 23.

The remote control means described above employs a radio frequency link in a specific frequency band, but in modified embodiments that link may be provided in another electromagnetic frequency band or by other means including an acoustic or magnetic system.

Referring to Figure 3 there is illustrated a circuit diagram of the control circuitry employed to operate the motor of the unit.

The circuit is based around a programmable microprocessor 40, a suitable processor is device type PIC16C71. The microprocessor is programmed to operate the drive motor in response to a trigger signal and also in relation to the current drawn by the motor.

A trigger signal, to activate the circuit is applied to the microprocessor 40 by means of the trigger connection 41.

The microprocessor 40 is arranged to output signals to operate the drive motor. These signals are fed to interlock circuitry 42, which comprises a number of logic gates and is arranged to ensure that only appropriate signals are applied to the motor, for instance to prevent the circuit from attempting to drive the motor in two directions simultaneously. The output from the interlock circuitry 42 is applied to a level shifter 43 (device type 4504) which enables the voltage of the motor drive signal to be set at an appropriate level to run the motor. The level shifter 43 outputs a signal which is fed to the motor via diodes 44 which are arranged to protect the circuit from any back emf. The drive motor is connected to terminals 45,46.

The current drawn by the motor is monitored by the potential divider 45, amplifier 49 and associated components.

The amplifier 49 outputs a signal corresponding to the current supplied to the motor, and this signal is transmitted to the microprocessor 40.

The circuit also provides a number of other functions.

Diodes 50 and resistors 51 form a battery level monitor, information as to the electrical condition of the batteries is transmitted to the microprocessor.

A speaker 52 and associated components 53 enables an audible warning signal to be generated to indicate, for example, that the barrier is moving.

A light emitting diode 54 and associated components enable a visual signal to be produced, for example, to indicate the battery condition.

The components 55 form a conventional voltage regulator to supply the circuit with a stable power supply.

A crystal 56 and associated components provide a clock signal to drive the microprocessor 40.

The trigger signal is provided by a conventional receiver, not illustrated, which is adapted to produce a signal in response to the receipt of a radio, or other signal, produced by an associated conventional transmitter.

The microprocessor is programme to allow the unit to perform the functions described above. For example, when the fingers are in the upright locked position, upon receipt of a signal at the trigger connection 41 the microprocessor 40 operates the drive motor to move the fingers to the horizontal position. When the fingers reach the limit of travel the increase in the current drawn by the drive motor causes the microprocessor to cease supplying the power to the drive motor. Upon receipt of a further trigger signal the drive motor is activated to raise the fingers to the upright position.

By comparing the time taken before the drive motor stalls, compared with the expected time taken to raise or lower the fingers the microprocessor can distinguish between the fingers making contact with an end stop or an unexpected obstruction.

Although the design and operation of the traffic control unit have been described above with specific reference to a battery-powered surface mounted version, it will be evident to one skilled in the art that the invention may readily be implemented in other formats to provide remotely-controlled moving barriers differently formed and otherwise powered or mounted, and used for controlling access of personnel, animals or other moving objects than vehicles. The invention may also be applied with ease to temporary installations, where its self contained, self powered nature makes it particularly suitable.

Claims (17)

1. CLAIMS 1. A powered traffic control unit comprising a base, traffic control means pivotally mounted on the base, and drive means for moving the traffic control means from a first operative position to a second inoperative position.
2. 2. A control unit as claimed in claim 1, in which the control means is a plate.
3. 3. A control unit as claimed in claim 1, in which the control means comprises one or more teeth or fingers.
4. 4. A control unit as claimed in claim 3, including a cover through which the teeth or fingers project when in the operative position.
5. 5. A control unit as claimed in claim 1, in which the drive means comprises an electric motor driving a shaft on which the control means is mounted.
6. 6. A control unit as claimed in claim 5, in which power for the electric motor is provided by an electric battery.
7. 7. A control unit as claimed in claim 5, in which power for the electric motor is provided by mains electricity or solar power.
8. 8. A control unit as claimed in any preceding claim, including electronic control means for controlling the operation of the drive means.
9. 9. A control unit as claimed in claim 8, in which the electronic control means includes means for determining the position of the flow control means relative to the base plate.
10. 10. A control unit as claimed in claim 9, in which the means for determining the position of the flow control means monitors the current drawn by the electric motor.
11. 11. A control unit as claimed in claim 9, in which the means for determining the position of the flow control means includes photo-detectors, micro-switches, or a timer.
12. 12. A control unit as claimed in claim 9, in which the electronic control means includes means for distinguishing between end of travel and collision with an obstruction, and in the event of the latter, to reverse automatically the barrier direction, for a short distance before stopping.
13. 13. A control unit as claimed in claim 12, including resilient end stops limiting the movement of the control means.
14. 14. A control unit as claimed in any of claims 8 to 13, in which the electronic control means includes a radio receiver adapted to receive a predetermined coded radio signal from an associated transmitter to operate the traffic control means.
15. 15. A control unit as claimed in claim 14, in which the radio receiver monitors either continuously or for pre-determined timed intervals for transmissions, and on receipt of a valid code operates the drive means to either raise or lower the flow control mechanism.
16. 16. A control unit as claimed in any preceding claim, including means for locking the traffic control means in its first operative position.
17. 17. A control unit substantially as hereinbefore described with reference to and as shown in the accompanying drawings.