GB2369226A

GB2369226A - Traffic control system

Info

Publication number: GB2369226A
Application number: GB0028213A
Authority: GB
Inventors: Richard Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-11-18
Filing date: 2000-11-18
Publication date: 2002-05-22
Anticipated expiration: 2020-11-18
Also published as: GB2369226B; GB0028213D0

Abstract

A traffic control system incorporating a base unit (1) supporting a rotating circular disc (10) bearing a GO sign (11) on one side and a STOP sign (12) on the other. A hand held wireless controller (2) incorporates two control GO buttons (4) and a control button STOP (6) to cause an electric motor (13) in the base unit (1) to position the circular disc (10) to display, on demand, either GO sign (11) or STOP sign (12) to be displayed to oncoming traffic. The hand held wireless controller (2) when coupled with the base unit (1) provides a programming means using the operating GO buttons (4) and STOP button (6) to programme the system providing independent operation of any base unit (1) with any hand held wireless controller (2). The base unit also incorporates a Hall effect magnetic device to determine the current position of the rotating disc.

Description

TRAFFIC CONTROL SYSTEM This invention relates to a traffic control system using indicator signs, especially, but not exclusively, for controlling the passage of traffic or pedestrians.

One of the simplest forms of temporary traffic control system is a manually operated STOP/GO sign, which involves one operator standing beside the sign and operating it to minimise traffic delays. This is satisfactory provided the obstruction to the traffic is small, and traffic from both directions can see the sign. Frequently this is not the case, when it is necessary to have two signs operated at each end of the traffic obstruction. In this case the two operators need to be in visual contact. This is less satisfactory than the single sign, since errors could arise between the two operators. This system is labour intensive since it involves two operators, and provision has to be made to relieve each periodically.

A traffic control system which involves one operator controlling two STOP/GO signs by wireless means is described in International Publication Number PCT W095/20206. This system uses complex circuitry to sequence the STOP/GO sign position with a fixed programmed hand controller combined with two similarly programmed base units. This fixed controlled sequential system is inflexible to traffic demands and to possible field failure, as part replacement is not possible. Due to the nature of sequencing should it become corrupted it is possible to display two GO signs simultaneously.

With the problems of inflexibility to traffic demands, and the more serious safety issue of the possibility of displaying two GO signs simultaneously, an improved system which addresses these problems is required.

According to the present invention there is provided a traffic control system comprising of one or two identical programmable base units each supporting an electrically driven rotating sign having two faces ; one face bearing a GO indication, and the other bearing a STOP indication, and a portable, hand held wireless controller, to control each base unit by independently positioning the appropriate face, STOP or GO, to face oncoming traffic.

By a GO indication it is meant as the word GO (in any language) and for a green colour and/or any other symbol, word or colour which is generally recognised as permitting oncoming traffic to pass. Similarly, by a STOP (in any language) and/or a red colour and/or any other symbol, word or colour, which is generally, recognised as requiring oncoming traffic to STOP.

In the embodiment, the base units are independently programmed, by means of an incorporated proximity device, which responds to a manually controlled, portable, hand held wireless controller, which has a three-button keypad, hermetically sealed against vapour ingress.

An important feature of the control system is that the circuitry prevents simultaneous GO signals being displayed.

A main feature of the control system is the ability to re-operate the previously operated sign without the need for sequencing, and the ability of the pre-determined STOP time interval to be shortened by the operator to improve the flow of traffic and cater for emergencies.

A further feature is the one-hour timer, which will shut down the control system and conserve battery power if no valid signals have been received from the hand held wireless controller for a duration of one hour.

Safety features include a system to prevent operation if the battery voltage falls below a level which will prevent correct operation of the base unit, and an inhibit on the operation of the electric motor when programming the base unit.

Radio control systems suffer from interference especially code modulated systems, which are commonly used in traffic control equipment. An important feature of the invention is that it automatically reverts to display a STOP sign when the signal from the hand held wireless controller is corrupted by interference or the signal is terminated. To overcome the problem of a corrupted signal preventing the base unit operating correctly it can be connected to the hand held wireless controller by a data transmitting cable.

The base unit is mounted on a detachable frame, which incorporates retractable stabilising arms, protective handles, and wheels to ease transportation. The sign pole can be disengaged from the drive mechanism but is still supported by the base unit to enable manual operation of the sign.

Embodiments of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 shows the external visible components of a traffic control system using two base units and a hand held wireless controller.

Fig. 2 shows a base unit in more detail with the sign and pole removed and with the retractable arms engaging ground.

Fig. 3 shows a detailed view of the collar and drive engaging arrangement for the pole and sign.

Fig. 4 shows a base unit with the sign, pole, cover and frame removed.

Fig. 5 shows a block diagram of the base unit control system.

Fig. 6 shows a block diagram of the hand held wireless controller.

Referring to figure 1, a traffic control system is shown comprising two identical base units [I], and a portable, hand held wireless controller [2]. Both base units [1], when programmed, are operated independently, to control traffic in a restricted area such as road works.

The portable, hand held wireless controller [2] (shown in figure 1) incorporates an aerial [3] to transmit two encoded frequency modulated signals, each being selected by one of two control buttons GO [4] and individually dedicated by the operator (not shown) to program and operate one base unit [I], using only one of the GO [4] buttons or two base units [1] using both GO [4] buttons. Indicators [5] are incorporated to confirm the action of the control buttons GO [4] and inform the operator (not shown) that power is provided for transmission. A third control button STOP [6] switches the power off to the hand held wireless controller [2]. The hand held wireless controller [2] is powered by two standard AA battery cells [7] (shown in figure 6). A low-level battery indicator [81 visually informs the operator (not shown) when to change or recharge the two standard AA battery cells [7]. The base unit [1] (shown in figure 1) supports a vertically mounted pole [9] to which a circular disc [10] is attached. On one side of the circular disc [10], is the word GO [11] on a green background, and on the opposite side the word STOP [12] on a red background. The pole [9], and circular disc [10] is rotated about its own axis by an electric motor [13] (shown in figure 4) coupled to a drive shaft [141 (shown in figure 3) and collar [15]. The base unit [1] (shown in figure 1) contains electronic circuitry in a metal box [16] (shown in figure 4) to energise the electric motor [13] on command from the hand held wireless controller [2] (shown in figure 1).

The base unit [1] has a vertically mounted aerial [17] mounted on the base unit housing [18] to receive the coded transmission, and the signals are processed by the circuitry shown in figure 5.

To overcome situations of poor reception such as road works, the base unit [1] sensitivity can be substantially improved by coupling it to a supplementary aerial [19], which is mounted on top of a road works cone [20].

In figure 2 is shown the base unit [1] (shown in figure 1) with the pole [9] and circular disc [10] removed. The base unit [1] has a detachable mounting frame [21] (shown in figure 2) which incorporates retractable stabilising arms [22], which are locked into position vertically, to improve storage and transportation, and horizontally, to increase stability in use.

Wheels [23] (shown in figure 2), fitted to the detachable mounting frame [21], allows the base unit [1] (shown in figure 1) to be wheeled, when it is tipped sufficiently, using one of the protective handles [24], for the wheels [231 to run on the ground (not shown). The protective handles [24] can be used to stand the base unit [1] (shown in figure 1) vertically to reduce storage space.

To program a base unit [I I (shown in figure 1), the hand held wireless controller [2] is inserted in a recess [25] (shown in figure 2) in the base unit housing [18], which automatically activates the solid state-programming probe [26]. This activation is achieved by a magnet [27] (shown in figure 6), which is concealed in the hand held wireless controller [2] (shown in figure 1). The solid state programming probe [26] (shown in figure 2) is coupled to the circuitry shown in figure 5 and, when activated, allows programming of the base unit [1] (shown in figure 1) to take place by receiving and memorising the selected coded transmission from the hand held wireless controller [2] when a GO button [4] is depressed. When programming is complete, operating the respective coded transmission signal by pressing the appropriate control button GO [4] will result

in power being applied to the electric motor [13] (shown in figure 4) to rotate the pole [9] (shown in figure 1) and circular disc [10] through 1800 from STOP [12] to GO [11]. Ceasing transmission by operating the hand held wireless controller [2] STOP button [6] will signal the base unit [1] to rotate the pole [9] and circular disc [10] through a further 180'to display STOP [12], thereby placing the traffic control system, at rest. The base unit [1] will only respond to the dedicated programmed code first entered to cause the circular disc [10] to display GO [11]. Lost, interfered with, and terminated transmissions have the same effect as operating the control button STOP [6] on the hand held wireless controller [2]. Re-inserting the hand held wireless controller at any time in the recess [25] (shown in figure 2) in the base unit housing [18] re-activates the programming probe [26] and allows reprogramming of the base unit [1] (shown in figure 1).

Figure 3 shows detail of the drive shaft [14] connection to the pole [9] via a collar [15] and spigot [28]. The spigot [28] engages into a socket [29] welded to the pole [9]. This arrangement mechanically engages the drive shaft [14] to the pole [9], which retains its location by gravity. By lifting, rotating the pole [9] a few degrees, and then replacing, the spigot [28] is disengaged from the socket [29] allowing the pole [9] to be freely rotated manually should the base unit [1] (shown in figure 1) fail in operation. This arrangement provides an emergency means to control traffic whilst a replacement base unit [1] is obtained. The drive shaft [14] (shown in figure 3), collar [15], pole [9] and circular disc [10] (shown in figure 1) are indexed and only capable of being fitted to each other in one angular position and therefore on occasions when the pole has been removed its replacement is unambiguous.

In figure 4 the base unit [1] (shown in figure 1) is shown with the circular disc [10], pole [9], housing [18] (shown in figure 2) and frame [21] removed. The vertically mounted drive shaft [141 (shown in figure 4) is held by bearings [30]. A pulley [31] fixed to the drive shaft [14] is coupled by a segmented/toothed drive belt [32] to a smaller pulley [33] fixed to the electric motor [13]. The electric motor [131 is powered from a single 12volt battery [34]. A belt tensioning mechanism [35] secured by locking nuts [36] is provided and adjusted to optimise power transfer from the electric motor [13] to the drive shaft [14] and a segmented/toothed drive belt [32] is used rather than a conventional Vee belt (not shown) to substantially reduce the current supplied to the drive motor [13] and thereby to extend the life of the battery [34]. Incorporated within the base unit [1] (shown in figure 1) is a metal box [16] (shown in figure 4) containing the receiving and control circuitry shown in Figure 5. An additional encapsulated electronic module (not shown) contains the electric motor power drive module [37] (shown in figure 5).

Fitted to the drive shaft pulley [31] (shown in figure 4) are two indexing magnets [38] & [39] mounted 1800 apart, one indexing magnet [38] with its North Pole facing upwards, and the other indexing magnet [39] with its South Pole facing upwards. A single solid state Hall Effect shaft

position probe [40] mounted above the two indexing magnets [38] & [39] provides two independent electrical output signals, each responding to a sensed magnetic pole, to provide positioning logic of the drive shaft pulley [31] connected to drive shaft [14]. When the circular disc [10] (shown in figure 1) rotates 1800 and displays the desired indication to oncoming traffic (not shown), either indexing magnet [38] (shown in figure 4) or other indexing magnet [39] is sensed, and the electric motor [13] is stopped. Simultaneously, the Hall Effect shaft position probe [40] provides a signal to interface with the control logic [41] (shown in figure 5) to accept the next command to change the angular position of the circular disc [10] (shown in figure 1).

Referring to the schematic diagram of the base unit in Figure 5, power from the battery [34] is distributed via overload protection circuit [42] and excessive voltage thermal cut-out protection device [43] to drive the electric motor [13], standby 5-volt supply [44] and switchable main 5volt regulator supply [45]. The standby 5-volt supply [44] continuously powers the solid state programming probe [26], one-hour timer [46], and battery level monitor [47] circuits.

When the solid-state programming probe [26] is activated by inserting the hand held wireless controller [2] (shown in figure 1) into the recess [25] (shown in figure 2) in the base unit housing [18], the one hour timer [46] (shown in figure 5) is reset. The switchable main 5-volt regulator supply [451 is then switched'on'and a red supply indicator [48] is illuminated on the display panel [49] (shown in figure 2). Power is then routed to the receiver [50] (shown in figure 5), decoder [51], timer interval delays [52], control logic [41], electric motor power drive module [37] and the program probe inhibit [53]. The electric motor power drive module [371 is inhibited by the program probe inhibit [53] along with the output from the decoder [51]. This removes the possibility of the operator (not shown) being hit by the circular disc [10] (shown in figure 1) whilst engaging the hand held wireless controller [2] in the recess [25] (shown in figure 2) in the base unit housing [18]. During programming of the base unit [1] the decoder [51] (shown in figure 5) operates a yellow indicator [54] mounted alongside the red supply indicator [48] on the display panel [49] (shown in figure 2) and flashes until the code received has been accepted and memorised. When this action is complete, the yellow indicator [54] (shown in figure 5) illuminates continuously. When the hand controller [2] (shown in figure 1) is removed from the

recess [25] (shown in figure 2) in the base unit housing [18], the code accepted by the decoder [51] (shown in figure 5) cannot be altered unless the power to the standby 5v supply [44] is removed, or the programming probe [26] is reactivated. After a delay of three seconds the program probe inhibit [53] is removed and control of the electric motor [13] restored.

When the control buttons GO [4] (shown in figure 1) are pressed, on the hand held wireless controller [2], a frequency modulated coded radio signal is transmitted to the vertically mounted aerial [17] and demodulated within the receiver [50] (shown in figure 5). The signal is routed to the decoder [51]. The accepted decoder [51] output signal is routed to the timer interval delays [52] and after a period of four seconds, to verify signal presence, the one-hour timer [46] is reset and the shaft position logic [41] is interrogated. Should the position of the circular disc [10] (shown in figure 1) facing the oncoming traffic (not shown) be STOP, and the North Pole facing indexing magnet [38] (shown in figure 5) is sensed by the shaft position probe [40], the power drive module [37] switches on the electric motor [13]. The electric motor [13] rotates the circular disc [10] (shown in figure 1) until the drive shaft [14] (shown in figure 4) has turned 1800 and the shaft position probe [40] (shown in figure 5) senses the South-facing indexing magnet [39]. The sensed signal, combined with the logic [41] switches off the electric motor [13]. The sign GO [11] (shown in figure 1) is displayed as long as the accepted coded signal is received. When the transmission is terminated by operating the hand held wireless controller [2] control button STOP [6], the decoded output signal is removed and the timer interval delays [52] (shown in figure 5) is operated. After two seconds the logic [41] is interrogated and the electric motor [13] rotates the circular disc [10] (shown in figure 1) until the North Pole facing indexing magnet [38] (shown in figure 5) is sensed, when power is removed from the electric motor [13].

The base unit control system shown in figure 5, is now at rest and displaying STOP [12] (shown in figure 1) to oncoming traffic (not shown).

Should no further transmissions from the hand held wireless controller [2] (shown in figure 1) be accepted, the time derived by the one hour timer [46] (shown in figure 5) will elapse, and the power is then switched off to the main 5-volt regulator supply [45] and the base unit circuit is shut down apart from the electrical supply to the standby 5-volt supply [44]. There is no need to reset or index the traffic control system as both circular signs [10] (shown in figure 1), will display STOP when no signal is received.

Operation of the second base unit [1] (shown in figure 1) programmed and controlled by the other GO button [4] on the hand held wireless controller [2] is identical, and is performed according to the above programming description. Using two base units [1] and a hand held wireless controller [2] makes up a system suitable for temporary road works where the GO button [4] logic of the hand held wireless controller [2] coupled with the pre-determined timer interval delays [52] (shown in figure 5) inhibits the display of simultaneous GO [11] (shown in figure 1) signs.

The battery potential is continuously monitored by the battery level monitor [47] (shown in figure 5) and when the low level is exceeded, and it is likely that uncertain operation may result from an exhausted battery [34], the main 5 volt regulated supply [45] is switched off, by the battery low level inhibit [55] after a delay of three seconds [56], together with the electric motor power drive module [37]. Hysteresis technique is employed to ensure the main 5-volt regulator supply [45] does not switch on when the battery potential partially recovers. The red supply indicator [48] now flashes to warn the operator of the low battery potential. The operation of the base unit circuitry shown in figure 5 can only be restored to normal after the battery [34] has been recharged to an acceptable level. Should the base unit [1] (shown in figure 1) be displaying STOP [12] to oncoming traffic (not shown) then the electric motor [13] (shown in figure 5) will be disengaged immediately by the inhibit battery low level [57]. However, should the base unit [1] (shown in figure 1) be displaying GO [11] then the circular disc [10], will be rotated through 180"to display STOP [12]. This operation takes two seconds, and the base unit main 5volt supply [45] (shown in figure 5) is switched off by the inhibit [55] via a 3 second delay [56]. The standby 5v supply [44] maintains the battery level monitor [47] active, and when the battery [34] has been recharged at the charger input [58] to a minimum of 90% capacity, the flashing red indicator [48] will extinguish indicating the base unit [1] (shown in figure 1) is ready for use.

The voltage level of the battery [34] (shown in figure 5) is displayed continuously on the display panel [49] (shown in figure 2) to further assist the operator (not shown) in assessing the battery condition.

The frequency-modulated receiver [50] (shown in figure 5) has the capability of operating when excessive signal level is applied. If interference is experienced which affects the control system performance the receiver [50] can be connected directly via BNC input connector [59] to the hand held wireless controller [2] (shown in figure 1) BNC output connector [60] (shown in figure 5) using a coaxial cable (not shown).

Figure 6 shows a block diagram of the hand held wireless controller [2] (shown in figure 1) which is powered using two AA battery cells [7] (shown in figure 6) which can be of any manufacture, i. e. Alkaline, carbon, rechargeable, Nicad, MNiH etc. A step up dc-dc switching regulator [61] is employed to give a constant dc power level to the circuitry, providing consistent and reliable performance, throughout the life of the two AA battery cells [7]. The dc-dc switching regulator [61] provides continuous power to the keypad logic [62], and power supply switches [63]. A low-level battery indicator [8] visually informs the operator (not shown) when to change or recharge exhausted battery cells [7].

The BNC [60] (shown in figure 6) aerial [3] connection is also used to provide a battery charger input should permanently installed battery cells [7] be employed or a hermetically sealed housing without access to the battery cells [7] be used.

The three-button tactile keypad [64] (shown in figure 6) is hermetically and environmentally sealed. The very low power consuming keypad logic [62] is controlled by the operation of control buttons GO [4] and control button STOP [6] and is permanently connected to the power supply provided by the dc-dc switching regulator [61]. Pressing either of the GO [4] buttons switches the power supply switches [63] on and transmission takes place automatically. Pressing the STOP button [6] switches the power supply switches [63] off, eliminating the need for a separate supply switch to conserve power after transmission. The hand held wireless controller [2] (shown in figure 1) is internally pre-programmed such that either one of the control buttons GO [4] is non-operational immediately following activation of the other control button GO [4], unless the control button STOP [6] is activated before the said other control button GO [4]. This arrangement prevents the two base units [I], when programmed, to respond and display GO signs [11] simultaneously. To eliminate misuse of the hand held wireless controller [2], by rapid and/or random operation of the control buttons GO [4] and control button STOP [6], the received signal needs to be continuously present to satisfy the predetermined time interval delays [52] (shown in figure 5) built into the base unit control circuitry. This system allows either of the two base units [1] (shown in figure 1) to be operated independently and not necessarily in sequence. One or both base units [1] can be fully operated without the need to modify the hand held wireless controller [2]. Either or both base units [I I and/or the hand held wireless controller [2], can be replaced and its replacement can be put immediately into operation using the on-site programming facility.

Each hand held wireless controller [2] (shown in figure 1) incorporates an encoder [65] (shown in figure 6), which has its own unique pre-set codes [66]. The output of the encoder [65] modulates a FM transmitter [67] and the resulting signal is transmitted via aerial [3].

Claims

Claims 1. A system providing stop/go indicator signs for controlling the passage of traffic or pedestrians, the system comprising two identical base units with ground engaging means adapted to facilitate repositioning and a pre-programmed hand-held portable controller wherein the said controller incorporates a three button keypad hermetically sealed against vapour ingress and is internally programmed to dedicate it's operation to one or other of the base units by respective operations of a respective one of two, go buttons, of the said three buttons, wherein the said controller further incorporates an internal device which in proximity to the base unit and using the said operating buttons enables dedicated programming of any base unit via a wireless link to match said controller.
2. A system as claimed in claim 1 wherein, said controller is pre-programmed such that either one of the said two buttons is ineffective in operation immediately following activation of the other of the said two buttons unless the third, stop, button is activated before the said other button.
3. A system as claimed in either of claims I or 2 wherein the said internal device is a magnet, which activates a Hall-Effect device in the base unit
4. A system as claimed in any preceding claim wherein the pre-programmed logic of the said base unit after a pre-determined time interval to verify signal integrity from the controller, allows activation of the respective base unit in its go condition.
5. A system as claimed in any preceding claim wherein the pre-programmed logic of the said base unit after half the said time interval allows activation of the respective base unit in its stop condition.
6. A system as claimed in claim 4 and S wherein the pre-programmed logic of the said base unit uses the said pre-determined time intervals for stop and go to prevent simultaneous go signals being displayed.
7. A system as claimed in claim 4 wherein said maintained activation is allowed by a repeated activation of said go button following a reduced time interval after stop has been selected so as to improve the flow of traffic.
8. A system as claimed in any preceding claim wherein a single base unit can be operated by the said hand controller without any modification or control changes.
9. A system as claimed in any preceding claim wherein to conserve power a resetable timer is incorporated to switch off the battery supply when the system has been idle for a set period.
10. A system as claimed in any preceding claim wherein the base units are releasable attached to a mounting frame incorporating said ground-engaging means.
11. A system as claimed in any preceding claim wherein the base units are connected to the hand held wireless controller by a data transmitting cable.
12. A system as claimed in any preceding claim wherein each base unit incorporates an indicator sign drive shaft and a motor mechanically interconnected by a toothed drive belt
13. A system as claimed in any preceding claim wherein the indicator sign is detachable from the sign drive shaft for manual operation without movement of the said drive belt.
14. A system as claimed in claim 1 and substantially as herein described and as illustrated in the accompanying drawings.