GB2398126A

GB2398126A - Detecting the thickness of a road marking

Info

Publication number: GB2398126A
Application number: GB0325994A
Authority: GB
Inventors: Christopher Francis Ward; Wouter Staal
Original assignee: VOTR CONSULTING Ltd
Current assignee: VOTR CONSULTING Ltd
Priority date: 2002-11-09
Filing date: 2003-11-07
Publication date: 2004-08-11
Anticipated expiration: 2023-11-07
Also published as: GB2398126B; GB0325994D0; GB0226193D0

Abstract

Apparatus 30 for measuring the thickness of a marking 15 on a surface, the apparatus 30 comprising surface detection means 1 adapted to detect a surface 3, marking detection means 1 adapted to detect a marking 15 on the surface 3, and processing means 20 adapted to determine the thickness of the marking 15 on the surface 3, based on output from the surface detection 1 means and the marking detection means 1. This arrangement can be used to determine the thickness of painted road markings by determining the difference in level between the top and the bottom of the marking. The uneveness of the surface adjacent to the marking is compensated for by averaging a plurality of readings.

Description

APPARATUS FOR MEASURING THE THICKNESS OF A MARKING ON A

SURFACE

A general aspect of this invention is that there is provided an electronic measuring system for determining the thickness of road marking paint.

According to a first aspect of the present invention, there is provided apparatus for measuring the thickness of a marking on a surface, the apparatus comprising surface detection means adapted to detect a surface, marking detection means adapted to detect a marking on the surface, and processing means adapted to determine the thickness of the marking on the surface, based on output from the surface detection means and the marking detection means.

The surface may comprise a road, motorway, lane, or other surface on which a vehicle may travel. The marking may comprise paint, or other materials or composites used to create road markings. The surface may comprise a railtrack and the marking may comprise a rail or sleeper.

Preferably, the apparatus comprises support means on which the surface detection means and preferably, the marking detection means may be carried. The support means may comprise a frame, which frame preferably comprises a plurality of leg members. Preferably, the leg members are spaced apart preferably at sufficient distance such that, in use, the apparatus can be arranged to straddle a marking on a surface. Preferably, the apparatus is adapted to be placed in use over or adjacent the marking on the surface.

Preferably, the surface detection means is adapted to detect the position, height or level of the surface.

Preferably, the marking detection means is adapted to detect the position, height or level of the marking, preferably with respect to the surface.

Preferably, the surface detection means, and preferably, the marking detection means, comprises at least one elongate member, preferably a plurality of spaced apart elongate members. Preferably, the or each elongate member is adapted to move towards and away from the support means. Preferably, the or each elongate member is slidably mounted on to the support means. The elongate member may comprise a shaft or pin.

Preferably, the or each elongate member is adapted in use to move along a path which is substantially transverse to, and more preferably substantially perpendicular to, the support means. Preferably, the or each elongate member is adapted in use to move along a path which is substantially vertical with respect to the surface.

Preferably, the surface detection means, and preferably, the marking detection means, comprises biasing means operable to urge the or each elongate member away from the support means. Preferably, the or each elongate member is adapted to move between an elongate member extended position and an elongate member retracted position.

Preferably, the biasing means urges the or each elongate member in to the elongate member extended position.

Preferably, the extended position for the or each elongate member of the surface detection means and the extended

-

position for the or each elongate member of the marking detection means are substantially at the same distance away from the support means as each other. Preferably, the elongate member extended position extends beyond the support means, preferably an end thereof, preferably a lower portion thereof. Hence, preferably, the or each elongate member of both the surface detection means and the marking detection means extends further away from the support means than the frame, for example, the leg members.

Preferably, the or each elongate member of the surface detection means is adapted in use to contact the surface, which may be adjacent a marking on the surface, and move from the elongate member extended position towards the support means. Preferably, at least one elongate member of the surface detection means is arranged, in use, to contact the surface either side of the marking.

Preferably, the or each elongate member of the marking detection means is adapted in use to contact the marking and move from the elongate member extended position towards the support means. It will be appreciated that due to the inherent thickness of the surface marking, the or each elongate member of the marking detection means will move a greater distance from the elongate member extended position that will the or elongate member of the surface detection means. This greater distance equates to the thickness of the surface marking.

Preferably, the surface detection means, and preferably, the marking detection means, includes a transducer which is adapted to convert the distance moved by the or each

- l

elongate member in to a measurable electrical signal, such as voltage. The transducer may be a potentiometer.

Preferably, the processing means is operable to calculate the difference between the distance moved by the or each elongate member of the surface detection means and the distance moved by the or each elongate member of the marking detection means, based on the voltage from the transducer. Preferably, the processing means is operable to calculate the average distance moved by the elongate member of the surface detection means, and preferably the average distance moved by the elongate member of the marking detection means, based on the voltage from the transducer. Preferably, the difference between these two (average) distances equates to the thickness of the marking on the surface.

According to a second aspect of the present invention, there is provided a method for measuring the thickness of a marking on a surface, the method comprising detecting a surface with surface detection means, detecting a marking on the surface with marking detection means, and determining the thickness of the marking on the surface, based on output from the surface detection means and the marking detection means.

All of the features described herein may be combined with any of the above aspects, in any combination.

Advantageously the measuring system utilises analogue and digital electronics as a processing means thereby providing a method of measuring the thickness of road marking paint when compared against the surface texture either side of the road marking.

This aspect is especially important for the systems proposed use as Highways Authorities, Contractors and Road Safety Agencies are presently not able to provide accurate, objective data concerning the thickness of road marking paint applied to road surfaces.

Advantageously, the system utilises analogue and digital electronics as a processing means. This enables the system to detect and quantify the difference between the level of the top and bottom of the road marking.

Advantageously, the processing capability of the analogue and digital technology embodied within the system enables the data to be stored and/or down loaded onto a computer disc in a format enabling future analysis utilising appropriate computer software.

Advantageously the apparatus utilises a series of spring- loaded shafts fixed to reference plate (at a set height above the area of interest). These shafts are free to move in a vertical direction such that the elevated position of the shafts corresponds with points on the texture of the surface upon which the bottom of the shafts are resting.

The difference in the height of the shafts is then measured electronically using the processing means. See figure 1.

Advantageously the shafts are connected to a series of variable resistors, which are used to alter the input voltage to a different level.

Advantageously both analogue and digital methods of signal analysis are used as the basis of the electronic processing means.

Advantageously the analytical circuit resembles a simple arithmetic computer, which works on the principle that when a number is put into the system the computer makes various arithmetic changes to this number, and then churns out a new number. It will make the same changes to any number that is put into the system. The basic functions of the circuitry are outlined in figure 1.

Desirably the processing means require fixed inputs from fixed places. That is why in figure l there are two inputs, one from the road markings, and one from the road surface.

Advantageously because there are multiple sensors on each surface, these values can be averaged i.e. Adding all the inputs and dividing it by the number of inputs.

Advantageously the processing means carries out this function for both sets of data (road surface and road marking) and calculates the difference between the two values, which corresponds to the mean thickness of the road marking paint within the area of interest.

Advantageously the apparatus is portable and is therefore supplied from a portable power source in the form of a battery.

Desirably the processing means requires a consistent power supply voltage, this is achieved by incorporating two voltage regulators within the electrical circuitry.

Desirably there are many requirements that have to be met in order that this instrument will be valid i.e. measure the thickness of road markings i.e. the structure has to rigidly hold the sensors, which will be taking a reading off the road as well as the circuitry, batteries, switches and read out display.

Advantageously a structure constructed out of aluminium has been designed, see figure 3, which rigidly holds the sensors, thereby minimising any deflection in the structure caused by the compression of the spring loaded shafts.

Desirably the processing means stores data on thickness of the road marking within the area of interest. Preferably a predetermined level of acceptable thickness of road marking paint is incorporated into the processing means with appropriate circuitry and signal analysis indicating pass or fail.

Preferably in addition to storing the data, a hard copy of the data can be reproduced if it is required, as objective evidence that the road marking does or does not comply with the said predetermined acceptable thickness of road marking paint.

Advantageously the process function further includes the step of filtering the data by calculating the mean thickness of the road marking paint over a given area by analysis of the sum of individual readings derived from the processing means.

Preferably the process further includes the step of storing on any suitable medium a complete record of all measurements together with location, direction, date, time and any other relevant information.

Preferably the process further includes the step of converting the data from the processing means into a format for telecommunication and/or presentation in either graphical or numerical form.

It is an object of this invention to provide a system and IS apparatus capable of measuring the thickness of road marking paint in situ, without destroying the road marking.

It is another object of this invention to measure the thickness of road marking paint whilst taking into account the texture (i.e. peaks and troughs) of the road surface either side of the road marking.

It is another object of this invention to measure the thickness of the road marking paint when the paint is laid upon any textured or smooth surface.

It is another object of an embodiment of this invention to provide a system, method and apparatus capable of measuring the difference in height of any surface (smooth or textured) caused by the incorporation of any form of equipment, apparatus or system which alters the texture of the surface in question.

Desirably it is a further object of an embodiment of this invention that the apparatus can be mounted on some form of carriage.

Description of Drawings

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a profile gauge sitting on an idealised road marking together with the basic function of the circuitry involved.

Figure 2 shows a top view of the proposed structure (the circles representing the spring loaded shafts).

Figure 3 shows the structure for rigidly holding the sensors, PCBs, batteries and switches.

Referring to the drawing figure 1, the system 30 comprises a series of spring-loaded 32 shafts 1 fixed to a reference plate 2. The shafts 1 are free to move in a vertical direction 17 such that movement of the shafts 1 replicates the texture of the surface upon which the bottoms of the shafts 1 are resting 3 when the apparatus is pressed down.

The shafts 1 are connected to potentiometers 4 which convert the distance travelled 5 by the shafts 1 into a measurable level of electrical resistance 6 described as input. This input 6 is further converted by processing means 20 into a numerical value 7 described as output which equates to the mean distance travelled in millimetres by the shafts 1, which straddle the road marking 15 less (minus) the mean distance travelled by the shafts 1 either side of the road marking 15.

With reference to figure 2, three sets 8, 9, 10 of shafts 1 are incorporated into the apparatus 30. A set of four shafts 1 either side of the road marking 15 and a set of eight shafts 1 which sit on top of the road marking 15.

Referring to drawing figure 3, a frame-work structure 24 having corner legs 26 rigidly holds all of the shafts 1, sensors, batteries, circuits and switches such that any deflection caused by the spring force of the IS potentionometers 4 is minimal.

Method of Operation Referring to figure 1, the apparatus 30 is placed upon an area in question 11, which is to be examined, and pressed down until feet 12 of the apparatus 30 are resting on the surfaces of the area in question 11. The processing means averages 13 the distance travelled by the shafts 1 either side of the road marking 15. It also averages 14 the distance travelled by the shafts 1, which are resting on the road marking 15 and subtracts the two averages from each other, with the resultant difference 16 being the average thickness of the road marking 15 paint. This is displayed at output 7 in millimetres to two decimal places. This numerical value is then recorded by the processing means 20 and stored in a format which enables the production of objective hard copy data for recording and further analysis in either pictorial, graphical or numerical form.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. Apparatus for measuring the thickness of a marking on a surface, the apparatus comprising surface detection means adapted to detect a surface, marking detection means adapted to detect a marking on the surface, and processing means adapted to determine the thickness of the marking on the surface, based on output from the surface detection means and the marking detection means.

2. Apparatus as claimed in claim l, wherein the surface comprises a road, motorway, lane, or other surface on which a vehicle may travel.

3. Apparatus as claimed either in claim l or claim 2, wherein the marking comprises paint, or other materials or composites used to create road markings.

4. Apparatus as claimed in any preceding claim, wherein the apparatus comprises support means on which the surface detection means and the marking detection means are carried.

5. Apparatus as claimed in claim 4, wherein the support means comprises a frame.

6. Apparatus as claimed in claim 5, wherein the frame comprises a plurality of leg members.

7. Apparatus as claimed in claim 6, wherein the leg members are spaced apart at sufficient distance such that, in use, the apparatus can be arranged to straddle a marking on a surface.

8. Apparatus as claimed in any preceding claim, wherein the apparatus is adapted to be placed in use over or adjacent the marking on the surface.

9. Apparatus as claimed in any preceding claim, wherein the surface detection means is adapted to detect the position, height or level of the surface.

10. Apparatus as claimed in any preceding claim, wherein the marking detection means is adapted to detect the position, height or level of the marking.

11. Apparatus as claimed in any preceding claim, wherein the surface detection means and the marking detection means comprise at least one elongate member.

12. Apparatus as claimed in claim 11, wherein the or each elongate member is adapted to move towards and away from the support means.

13. Apparatus as claimed in either claim 11 or claim 12, wherein the or each elongate member is slidably mounted on to the support means.

14. Apparatus as claimed in any of claims 11 to 13, wherein the elongate member comprises a shaft or pin.

15. Apparatus as claimed in any of claims 11 to 14, wherein the or each elongate member is adapted in use to move along a path which is substantially transverse to the support means.

16. Apparatus as claimed in any of claims 11 to 15, wherein the or each elongate member is adapted in use to move along a path which is substantially vertical with respect to the surface. s

17. Apparatus as claimed in any of claims 11 to 16, wherein the surface detection means and the marking detection means comprise biasing means operable to urge the or each elongate member away from the support means.

18. Apparatus as claimed in any of claims 11 to 17, wherein the or each elongate member is adapted to move between an elongate member extended position and an elongate member retracted position.

19. Apparatus as claimed in claim 18, wherein the biasing means urges the or each elongate member in to the elongate member extended position.

20. Apparatus as claimed in either claim 18 or claim 19, wherein the extended position for the or each elongate member of the surface detection means and the extended position for the or each elongate member of the marking detection means are substantially at the same distance away from the support means as each other.

21. Apparatus as claimed in any of claims 18 to 20, wherein the elongate member extended position extends beyond the support means.

22. Apparatus as claimed in any of claims 18 to 21, wherein the or each elongate member of the surface detection means is adapted in use to contact the surface, which is adjacent a marking on the surface, and move from the elongate member extended position towards the support means.

23. Apparatus as claimed in any of claims 11 to 22, wherein at least one elongate member of the surface detection means is arranged, in use, to contact the surface either side of the marking.

24. Apparatus as claimed in any of claims 18 to 23, wherein the or each elongate member of the marking detection means is adapted in use to contact the marking and move from the elongate member extended position towards the support means.

25. Apparatus as claimed in any of claims 18 to 24, wherein the surface detection mean and the marking detection means, include a transducer which is adapted to convert the distance moved by the or each elongate member in to a measurable electrical signal.

26. Apparatus as claimed in claim 25, wherein the transducer is a potentiometer.

27. Apparatus as claimed in either 25 or claim 26, wherein the processing means is operable to calculate the difference between the distance moved by the or each elongate member of the surface detection means and the distance moved by the or each elongate member of the marking detection means, based on the voltage from the transducer.

28. Apparatus as claimed in any of claims 25 to 27, wherein the processing means is operable to calculate the average distance moved by the elongate member of the surface detection means and the average distance moved by the elongate member of the marking detection means, based on the voltage from the transducer.

29. Apparatus as claimed in claim 28, wherein the difference between these two (average) distances equates to the thickness of the marking on the surface.

30. A method for measuring the thickness of a marking on a surface, the method comprising detecting a surface with surface detection means, detecting a marking on the surface with marking detection means, and determining the thickness of the marking on the surface, based on output from the surface detection means and the marking detection means.

31. Apparatus for measuring the thickness of a marking on a surface substantially as herein described as illustrated in and with reference to the drawings.

32. A method for measuring the thickness of a marking on a surface substantially as herein described with reference to, and as illustrated by, the drawings.