GB2052743A

GB2052743A - Accident recording system

Info

Publication number: GB2052743A
Application number: GB8016441A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-05-18
Filing date: 1980-05-19
Publication date: 1981-01-28
Also published as: GB2052743B; DE2920090A1; FR2456978A1

Abstract

An accident recording system comprises a tachometer 16 and an A/D converter 15 which supply vehicle speed values to a shift register 17. Under the control of a clock pulse generator 23, a new vehicle speed is recorded each time the vehicle travels a predetermined distance and the old speed values are eventually cancelled. Alternatively a new vehicle speed is recorded at regular time intervals under the control of a clock pulse generator 22 actuated only when the vehicle is moving. After an accident, the speed values stored in the shift register 17 and identification data stored in a read-only-memory 19 may be read out by a recorder 25 situated in a police vehicle and stored on a magnetic card 26. <IMAGE>

Description

SPECIFICATION Accident recording system This invention relates to an accident recording system for a vehicle having a memory for recording the vehicle speed, in which, in use, new speed values are continuously recorded and old speed values are cancelled.

The equipping of commercial vehicles with speed recorders is already known which ensure the recording of the vehicle speed. In this way it can be determined when the vehicle was operative and at what speed it was driven.

Accident recorders are also known, in which an endless magnetic tape loop records the vehicle speed and the old previously-recorded driving speed may be cancelled at an appropriate position. In the event of an accident the speed pattern of the last completed journey is recorded on the magnetic tape and can be recallea.

Both types of recorder require the installation of costly recorder equipment in the vehicle. The recorder instruments have mechanical drive arrangements and in consequence are not maintenance-free over an extended period.

The increasing introduction of anti-locking systems in vehicle brakes prevents determination of vehicle speeds by measurement of brake-tracks at the point of accident, owing to the absence of brake-tracks. Whilst, in the reconstruction of an accident, a knowledge of the speeds of the involved vehicles is of great importance. Owing to the relatively high cost and the need for regular maintenance the known speed recorders cannot be generally fitted to the majority of vehicles.

The purpose of the invention is to produce an accident recording system, only requiring the installation of a relatively low-priced instrument into individual vehicles, which is completely maintenance free and is suitable as legal evidence for the reconstruction of an accident.

According to this invention there is provided an accident recording system for a vehicle comprising an electronic memory for recording the vehicle speed in which, in use, new speed values are continuously recorded and old speed values are cancelled, a recorder, an output terminal connected to the memory for connecting the memory to the recorder, and a switch for transferring the contents of the memory to the recorder upon operation thereof.

In this system, the vehicle only has the electronic memory, the contents of which cannot be optically read or called up without further equipment. The scope of the recording may be limited for instance to the last 600 metres covered. A resolution of 0.5 m to 1.0 m is generally sufficient. The recorder is located in a police vehicle, called to the scene of an accident.

The memory is connected by a conductor with the recorder located in the police vehicle and its contents are transferred to the recorder. The recorder thus transfers the memory contents to a data-carrier, which is then placed as evidence in the police file. The data-carrier is made available automatically without human intervention so that human error cannot intervene.

In the individual vehicle only the memory is installed, which could be manufactured at extraordinarily low cost as a result of integrated circuit mass production technique. Furthermore a socket connected for the police vehicle recorder cable can be provided in the vehicle, together with a switch for calling up the memory contents. The switch can be combined mechanically with the plug connection so that on connecting the cable the contents of the memory are called up immediately or after a given delay. The recorder, which requires a certain amount of maintenance and is subject to wear, is only located in the police vehicle and checked at specific test-locations so that individual vehicle holders are not affected by maintenance operations.

The speed values are determined at sequential scanning points. In order to determine the scanning points the memory can be connected to a clock signal generator, which produces a clock signal while the vehicle covers a given distance.

As an example a clock signal can be emitted every 0.5 m. In that case a new speed value is received by the memory every 0.5 m.

As an alternative, the memory may be connected with a clock signal generator which emits constant frequency clock pulses as the vehicle travels. As a result, a new speed value is recorded by the memory at specific time intervals, independently from the vehicle speed.

In order to prevent subsequent exchange of the date-carrier driving the recorder, a read-onlymemory is preferably provided together with each memory containing individual identification data which is transferred to the recorder. On calling up the memory this individual identification data is recorded on the data-carrier. This data differs from one vehicle to another and represents a form of identification. This identification is permanently associated with the recorded speed pattern. In this way errors are not possible and the origin of the identification and its allocation to the vehicle cannot be mistaken.

The read-only-memory can be connected to the recorder by a switch which controls a clock signal generator for clocking the memory. On actuating the switch the contents of the read-only-memory and of the memory are automatically read.

The recorder may be a magnetic card recorder which transfers the memory contents and eventualiy the contents of the read-only-memory to a magnetic tape. The magnetic tape may be on cards which are eventually added to the accident report. In order to safeguard the magnetic recording against further unauthorised modifications, various security- and codingprocedures may be applied, which do not form part of this invention.

Referring to the drawings, the following describes in greater detail a typical example of the invention, wherein: Figure 1 is a vehicle dashboard fitted with & memory, and Figure 2 is a circuit diagram for an accident recording system.

Figure 1 shows the usual type of vehicle dashboard. A memory device 10 is located behind the dashboard and only a socket 11 receiving a plug 12 on a connecting cable 13 and a switch 14, for example in the form of a push-button switch, being visible on the dashboard.

The memory device 10 comprises an analog/digital converter 15, which is connected to the vehicle tachometer 16 or to another speed measuring device, as well as the electronic memory 17, which may for instance be a semiconductor memory. The memory 17 is a multi-bit shift register the contents of which are shifted forward by means of clock signals fed by way of cable 1 8. The output of the memory 17 is connected to an output terminal in the form of socket 11.

The hand-actuated switch 14 connects the output of a read-only-memory 19 to the output socket 11. The read-only-memory 19 contains an identification number, which identifies the relevant instrument. On closing the switch 14 a delay circuit 20 is also switched on, triggering a clock signal generator 22 after a short delay The output of the clock signal generator 22 is connected to the clock input 18 of the memory 17.

During normal vehicle-operation the switch 14 is open. The individual speed values are then fed regularly into the memory 17. The memory capacity related for instance to a 600 metre stretch with a resolution of 0.5 m. The memory 17 consequently has 1200 multi-bit shift positions.

During vehicle travel the pulses for shifting the speed values in memory 17 are generated by a clock pulse generator 23 producing one clock pulse for every 0.5 m of travel. As an alternative it would also be possible to use the clock pulses of the clock pulse generator 22 to shift the contents of memory 17. In that case the clock pulse generator 22 could also be controlled in addition by an arrangement which determines if the vehicle is travelling or not and, when the vehicle is moving, the clock pulse generator 22 is actuated so that the memory 17 is clocked at a constant pulse frequency.

In the typical example shown here the contents of the memory can be called up on connecting cable 13 with its plug 12 to the socket 11. On subsequently closing the switch 14, the contents of the read-only-memory 19 are first read out and simultaneously the delay circuit 20 is triggered.

On completion of the reading of the read-onlymemory 19, the delay circuit 20 counts down, then triggers the clock pulse generator 22. This clocks the memory 17 from which the memory contents are transmitted. The switch 14 can be coupled with the plug 12 so as to ensure that the reading of the memory 17 only occurs after the plug 12 has established full contact with the socket 11.

The recorder 25 connected by cable 13 with the memory device 10 can be installed in a police vehicle. It comprises a card-feeder for a magnetic card 26, which is inserted into a feed slot 27. The magnetic card 26 has a longitudinal magnetic strip 28 on which the identification data from the read-only-memory 19 and the speed data from memory 17 can be recorded. Instead of a magnetic recording, or additionally, a recording with an optical display arrangement may also be made. The card 26 finally bears the instrument identification read from the read-only-memory 19 as well as the speed pattern of the last distance covered. Several cards 26 can therefore not be confused since each card is classified strictly according to a specific instrument or vehicle.

Claims

1. An accident recording system for a vehicle comprising an electronic memory for recording the vehicle speed in which, in use, new speed values are continuously recorded and old speed values are cancelled, a recorder, an output terminal connected to the memory for connecting the memory to the recorder, and a switch for transferring the contents of the memory to the recorder upon operation thereof.

2. A system as claimed in Claim 1 including a clock signal generator connected to the memory which, in use, produces a clock signal each time the vehicle travels a predetermined distance.

3. A system as claimed in Claim 1 or Claim 2 including a clock signal generator connected to the memory and which produces clock signals at a constant frequency.

4. A system as claimed in any one of the preceding claims including a read-only-memory containing individual identification data for transfer to the recorder.

5. A system as claimed in Claim 4 in which the read-only-memory may be connected to the recorder upon operation of the switch and in which the switch controls the fixed frequency clock signal generator.

6. A system as claimed in Claim 4 or Claim 5 in which the recorder is a magnetic recorder arranged for transferring the contents of the electronic memory and.thus the contents of the read-only-memory to magnetic strip.

7. An accident recording system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.