GB2410548A

GB2410548A - Lorry load height measurement device

Info

Publication number: GB2410548A
Application number: GB0401661A
Authority: GB
Inventors: Elliot Joseph Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-27
Filing date: 2004-01-27
Publication date: 2005-08-03
Also published as: JP2007519915A; AU2005207102A1; GB0401661D0; WO2005071358A1; EP1751496A1

Abstract

A measurement instrument for measuring the distance between two points, the device comprising: first and second rotatable measuring units; and a processor for processing data from the first and second measuring units and calculating the distance between the two points, wherein the first and second measuring units each comprise a rangefinder for measuring the distance from the measurement device to the first and second points respectively and an angle measurement device for calculating the angle through which the rangefinder is rotated in order to measure the distance to the said one of the points. To measure, for example, the height of a load on a lorry and provide a permanent record for display in the cab or for calculating the volume of an internal space.

Description

Measurement Instrument The present invention relates to a measurement

instrument for measuring the distance between two points, for example, the total height of a load on a low loader lorry from a road surface to the highest point of the load.

It is often desirable to have an accurate measurement of the height of a vehicle, particularly one which is carrying a load. Under EC regulations the total height of all commercial vehicles over 2.895m (9 feet 6 inches in UK) in length must be displayed in the cab of the vehicle at all times. When the load is of a regular shape, such as rectangular container, it is relatively easy to obtain a fairly accurate measurement of its height using conventional measuring sticks and the like. However, it is common for lorries to carry irregular shaped loads which are not so easily measured, for example, it is difficult to measure the total height of a low loader lorry carrying a traction engine from the top of the chimney of the traction engine to the road surface.

In these circumstances it is common for drivers to estimate the total height of the lorry and its load or to make rough measurements. This is unsatisfactory and in some circumstances can pose a considerable danger to the driver and other road users. For example, if the total height of the lorry and its load have not been accurately measured there is a real danger that the load may hit low bridges or other such obstructions.

Such hazards could be easi ly avoided by having a measurement instrument which could quickly and accurately provide measurements of the total height of a lorry and its load, especially when the load is of an irregular shape.

It is the object of the present invention to alleviate the problems of the prior art or at least to provide an alternative measurement instrument.

According to the present invention there is provided a measurement instrument for measuring the distance and/or angle between two points, the device comprising: first and second rotatable measuring units; and a processor for processing data from the first and second measuring units and calculating the distance between the two points, wherein the first and second measuring units each comprises a rangefinder for measuring the distance from the measurement instrument to the first and second points respectively and an angle measurement device for measuring the angle through which the rangefinder is rotated in order to measure the distance to the said one of the points.

It is preferred that the angle measurement device calculates the angle of rotation of the rangefinder relative to a line perpendicular to both of the points. This can be achieved by careful set up of the measuring instrument. For example, when the distance being measured is a height the instrument can be set up on a tripod and adjusted such that it is horizontal using a spirit level.

Alternatively, the instrument may be provided with means for determining the line perpendicular to the points. When the distance between the two points is a vertical height the means for determining the line perpendicular to the points may suitably comprise an artificial horizon. The artificial horizon may be integral to the instrument and provides information about the attitude of the instrument relative to the horizontal.

Using this information the processor can determine the angle of each of the rangefinders above and below the horizontal.

The rangefinder may suitably be an optical rangefinder or it may be a laser rangefinder.

When the rangefinder is a laser rangefinder the laser is preferably an infra-red laser.

Each measuring unit is preferably provided with a camera. The cameras are preferably orientated relative to a corresponding one ofthe rangefinders and are provided to record an image which includes the point at which the optical rangefinder is aimed. When the rangefinder is an optical rangefinder the camera may suitably be aligned parallel to a 1 i l laser of the rangefinder or it may be offset to a calibrated distance relative to a laser of the rangefinder.

Advantageously, the instrument is provided with at least one display screen. The display screen may suitably comprise a first portion, which in use displays an image as viewed by the camera located within the first measuring unit, a second portion, which in use di splays an image as viewed by the camera located within the second measuring unit and a third portion which in use displays data from the processor.

When the processor has calculated the distance between the two points it preferably produces an output comprising the measured distance and angle between the two points and the date and time at which the measurement was recorded. The output from the processor may also suitably comprise an image as produced by each ofthe cameras. The output may suitably be printed out by attaching the instrument to a printing device. This will provide a hard copy of the measurement data which may be displayed in the cab of a lorry as is required by law. Alternatively, the instrument may be connected to a dock in the cab of the lorry having a graphical and/or numerical display.

The processor can preferably record multiple measurements relative to a fixed point. The instrument preferably further comprises a GPS unit connected to the processor.

According to a second aspect of the present invention there is provided a method of measuring the distance and/or angle between two points, the method comprising: using an rangefinder to measure the distance to a first one of the points; using an angle measurement device to determine the angle of rotation required to move the rangefinder from its starting position to the first one of the points; storing the data relating to the first one of the points; using the rangefinder to measure the distance to a second one of the points; using an angle measurement device to determine the angle of rotation required to move the rangefinder from its starting position to the second one of the points; storing the data relating to the second one of the points; and transferring the data relating to the first and second points to a processor which calculates the distance between the two points.

Preferably a first rotatable measuring unit comprising a first rangefinder and a first angle measurement device measures the data relating to the first one of the points and a second rotatable measuring unit comprising a second rangefinder and a second angle measurement device measures the data relating to the second one of the points. The angle of rotation of the first and second angle measurement devices is preferably measured relative to a line perpendicular to both of the points.The rangefinder may suitably be an optical rangefinder or it may be a laser rangefinder.

For a better understanding of the present invention, reference will now be made to the accompanying drawings showing, solely by way of example, an embodiment of the present invention, in which: Fig. 1 is a schematic diagram showing the component parts of a measuring instrument; and Fig. 2 is a side view of a measuring instrument being used to calculate the total height of a lorry and its load.

Fig. 1 is a schematic diagram showing the component parts of a measuring instrument 2. The measuring instrument 2, comprises a first measuring unit 4 and a second measuring unit 6. The first measuring unit 4 and the second measuring unit 6 are rotatably mounted on a main body (not shown). The main body contains a processor 8 and other component parts of the measuring instrument. -s -

The first measuring unit 4 and second measuring unit 6 each comprise optical measuring equipment located within a housing (not shown). Each housing is mounted on the main body by a pivot point through its central axis, about which it is free to rotate.

Alternatively, the pivot point may be offset from the centre of the housing such that when the housing is rotated about the pivot point the optical measuring equipment moves from a position where it is shielded by the main body to a position where it is exposed for use. The first measuring unit 4 and the second measuring unit 6 are each provided with a spring loaded catch (not shown) which is received in a recess and serves to retain the respective measuring unit in a fixed position when not in use. The catch is easily overcome by the application of a rotational force by a user.

The first measuring unit 4 and second measuring unit 6 are symmetrically disposed about a central axis of the main body. The first, or left, measuring unit 4 measures the distance from the measuring instrument 2 to a first point. This may typically be the bottom of an object or the road surface on which a lorry is parked. The second, or right, measuring unit 6 measures the distance from the measuring instrument 2 to a second point. This may typically be the top of an object or the highest point of a load on a lorry.

The two points may be offset relative to each other. When this is the case the distance calculated is the vertical distance from the second point to the bottom ofthe object being measured.

The first measuring unit 4 and second measuring unit 6 each comprise the same components and will be described with reference to the first measuring unit 4. It will be understood that this description applies to the second measuring unit 6 and that the two units may in fact be interchangeable parts which may be fitted on either side of the measuring instrument 2. The same reference numerals will be used in both the first measuring unit 4 and the second measuring unit 6. The components parts of the first measuring unit 4 will be denoted (L) and the component parts of the second measuring unit 6 will be denoted (R). Such versatility reduces manufacturing costs since it is only necessary to manufacture a single type of measuring unit.

The first measuring unit 4 comprises an optical depth of field rangefinder I OL which is aligned parallel to a laser unit 1 2L. In an alternative embodiment the laser unit 1 2L may be slightly offset with respect the optical depth of field rangefinder lOL such that the two intersect at a certain predetermined distance. The laser unit 12L is an infrared laser and emits infrared light. In use, the infrared light from the laser unit 12 is aimed at the first point and the optical depth of field rangefinder 10 determines the distance from the measuring instrument 2 to said point. The operation of such optical depth of field rangefinders will be easily understood by someone of average skill in the art and will not be described in detail. The optical depth of field rangefinder 10 and the laser unit 12 are connected to the processor 8. The processor 8 receives distance data from each of the measuring units and uses this data to calculate the distance between the two points as will be described below.

In an alternative embodiment the optical depth of field rangefinders lOL, 1 OR may be replaced by laser rangefinders.

In addition to the optical rangefinder 1 OL and the laser unit 1 2L, the measuring unit 4 comprises a camera 1 4L and an angle measuring device 1 6L, both of which are also connected to the processor 8. The camera 14L is arranged to record an image of the fixed point at which the laser unit 12L is aimed at the moment at which the distance data is captured. The image produced by the camera 1 4L will show a laser spot and a portion of the target object at which the measuring unit 4 is directed. This image can be used to provide verification for the distance data as produced by the processor 8, as will be described below.

The angle measuring device 1 6L measures the angle through which the measuring unit 4 is rotated, relative to a set point, in order to aim the laser unit 1 2L at the chosen point.

When the measuring instrument 2 is being used to measure the height of an object the set point against which the angle measurement is taken is the horizontal. When this is the case the angle measuring device 16L measures the angle through which the first measuring unit 4 is rotated downwards, with respect to the horizontal, in order for the laser unit 1 2L to point at the bottom of the object. In the case of the second measuring unit 6, the angle measurement device 1 6R measures the angle through which the unit 6 is rotated upwards, with respect to the horizontal, in order for the laser unit 12R to point at the top of the object.

In order to provide accurate height measurements the measuring instrument 2 is provided with an artificial horizon 18. Such devices are used in aircraft and also called gyro horizons and provide an indication of the attitude of the instrument 2 in relation to the horizontal. The artificial horizon 18 is connected to the processor 8 and in conjunction with the data provided by the angle measurement devices 16 the processor is able to calculate the depth of the first measurement unit 4 below the horizontal and the height ofthe second measurement unit 6 above the horizontal. The artificial horizon 18 enables the user of the measuring instrument 2 to obtain accurate measurements regardless of whether or not the instrument 2 is held horizontally. In an alternative embodiment of the invention, the instrument 2 may not be provided with an artificial 1 S horizon 18 and instead it may be mounted on a tripod or stand which will ensure it remains stable. A simple device, such as a spirit level, may be used to ensure that the instrument 2 is horizontal before the distance data is captured. A spirit level may be provided integrally with the main body.

The main body is provided with a display screen 20 which is connected to each of the cameras 14 via the processor 8. The display screen 20 comprises a first portion (not shown) on the left-hand side thereof which, in use, shows an image as viewed by the camera 1 4L, located within the first measurement unit 4, a second portion (not shown) on the right-hand side thereof which, in use, shows an image as viewed by the camera 14R located within the second measuring unit 6 and a third portion (not shown) which, in use, displays the data captured by the instrument and any additional information, such as date/time. The cameras 14 are digital cameras with previewing and the images recorded by the cameras are stored in memory unit 22. The memory unit 22 is a removable memory media. Alternatively, the instrument 2 may be provided with an integral memory unit or a combination of a removable and an integral memory unit. In addition to the display screen 20, the instrument is also provided with conventional optical viewfinders (not shown) such that a user may choose to view the object using either the display screen 20 or the optical viewfinder. These features are found on many conventional digital cameras.

The instrument 2 is powered by a built-in power source 24. The power source 24 is a rechargeable battery pack. Alternatively, the instrument may be plugged into the mains to operate or it may run off conventional batteries. The instrument is turned off and on using switch 26. A back-up power source 28 is provided to provide power for the clock which is built into the processor 8 and must maintain the correct time and date even when the instrument 2 is switched off for extended periods. A keypad 30 is provided to facilitate the selection of features and to enable manual entry of data into the processor 8.

The instrument is also provided with a built-in GPS unit and compass 32. This component is optional and is not be provided on the standard model measuring instrument 2. The standard model measuring instrument 2 is used for measuring the height of an object and will therefore have no need for position data such as will be provided by a GPS unit 32. However, other applications ofthe unit, as will be described below, will benefit from such data. Consequently, the GPS unit 32 is shown connected to the processor 8.

As a further modification, the instrument may be provide with a remote control device such that the instrument may be set up and measurements recorded by a user in a remote location.

An application ofthe measuring instrument will nowbe described with reference to Fig. 2 which shows a side view of the measuring instrument 2 of Fig. 1 being used to measure the height of a flatbed lorry 36 carrying an irregular shaped load 38. It would normally be difficult to measure the combined height (C) of such a lorry 36 and its load 38.

The measuring instrument 2 is first turned on at switch 26 and the instrument 2 is held such that the target object, in this case the lorry 36 and its load 38, are sighted on the display screen 20. The artificial horizon 18 provides the processor 8 with data regarding the attitude of the instrument 2 in relation to the horizontal.

The first measuring unit 4 is rotated downwardly until the laser spot emitted by the laser unit 12L is positioned at a first point at the bottom of the target object. Depending on the proximity of the target object this may be determined either by viewing the target object directly or by viewing it on the first portion of the display screen 20 or through the optical viewfinder. Next, the second measuring unit 6 is rotated upwardly until the laser spot emitted by the laser unit 12R is positioned at a second point at the top ofthe target object. Again, this may be determined by viewing the target object directly or by viewing it on the second portion of the display screen 20 or through the optical viewfinder.

When both laser spots are satisfactorily positioned the user may activate the measuring instrument by pressing the shutter button 34. This sets the data capture process in motion. The optical depth of field rangefinders lOL, lOR send data to the processor regarding the distances (D1) and (D2) from the instrument 2 to each of the points. The processor 8 takes a reading from the artificial horizon 18 and each of the angle measuring devices 16L, 16R and determines the angle (a) below the horizontal of the first measuring unit 4 and the angle (b) above the horizontal of the second measuring unit 6.

In addition, upon the activation of shutter button 34, the cameras 14L, 14R in each of the measuring units 4,6 record still pictures of the points showing the position of the laser spots emitted by the laser units 12L, 12R. Any additional data which is required by the processor, such as data from the GPS unit 32 is also captured.

The processor 8 then performs a simple calculation to calculate the total height (C) of the target object as shown below with reference to Fig. 2. The total height (C) is not necessarily the distance between the two points but rather it is the distance of the second point above the ground.

Sample calculation The calculation is performed in two parts. Firstly, the depth (A) ofthe first point below the artificial horizon is calculated using the distance (D1) between the instrument and the point and the angle (a) below the horizontal.

Next, the height (B) of the second fixed point above the artificial horizon is calculated using the distance (D2) between the instrument and the second fixed point and the angle above the horizontal.

The total height is then calculated by adding the two figures together.

Depth A = sin a x distance (D1) = sin 42 x 2320 = 1552.312mm Height B = sin b x distance (D2) = sin 62 x 3600 = 3178.44mm Total height (C)oftarget object = 1552.312 + 3178.44 = 4730.752mm The example shown uses simple trigonometry to calculate the total height (C) of the target object. It will be understood that the processor 8 will be capable of performing other calculations based on the data received from the optical depth of field rangefinders 1 OL, 1 OR, the angle measuring devices 16L, 16R, and, optionally, the artificial horizon 18andtheGPSunit32.

As mentioned above, the instrument can provide a permanent record of the measured height of the lorry and its load. This is particularly useful since under EC regulations the total height must be displayed in the cab ofthe lorry. The processor 8 combines the images provided by the cameras 14 and the calculation performed using the captured data and produces an output showing the information and the time at which it was recorded. The output from the processor 8 can be printed such that a hard copy can be displayed in the cab of the lorry. This is particularly useful since the images show the laser spots at the top and bottom of the target object and thus can be used to verify that the height measurement applies to the particular load. In addition, the date and time, as supplied by the internal clock in the processor 8, can be added to the print out to verify that the measurement was recently recorded.

Alternatively, the instrument 2 may be provided with a dock which may suitably be located within the cab of the lorry and into which the instrument may be connected when the height measurement has been recorded. The dock may suitably be provided with a display, capable of displaying graphical data and/or numerical data. It is envisaged that a user would use the instrument 2 to record the total height of the vehicle and its load and then connect the instrument 2 to the dock, which provides a housing for the instrument 2 when not in use, and which will display the data output from the processor 8.

The above example shows how the instrument can be used to determine the height of an object such as a lorry and its load. However, the instrument 2 can be used to perform a number of different measuring functions.

The instrument can be used to measure horizontal distances and angles as well as vertical distances and it can be used to take more than two measurements, for example, for calculating the volume of any internal space, such as a cave or a cathedral.

An alternative use of the instrument would be at the scene of a road traffic accident where there is the need for measuring multiple angles from a convenient safe position.

This would be accomplished by mounting the instrument horizontally on a tripod with a clear view of the scene. The instrument would be aligned with a central point in the accident and used to take pictures of prominent points. This would allow a more complete view of the accident scene to be established, which will improve the context.

Additional information from the GPS unit 32 may also be utilised in this application.

The data obtained using the instrument 2 is compatible with CAD programs such as Ace) AutoCAD which allows the 3D mapping of the measurements.

Claims

Claims 1. A measurement instrument for measuring the distance and/or angle

between two points, the device comprising: first and second rotatable measuring units; and a processor for processing data from the first and second measuring units and calculating the distance between the two points, wherein the first and second measuring units each comprises a rangefinder for measuring the distance from the measurement instrument to the first and second points respectively and an angle measurement device for measuring the angle through which the rangefinder is rotated in order to measure the distance to the said one of the points.
2. A measurement instrument according to claim 1, wherein the angle measurement device calculates the angle of rotation of the rangefinder relative to a line perpendicular to both of the points.
3. A measurement instrument according to claim 2, wherein the instrument is provided with means for determining the line perpendicular to the points.
4. A measurement instrument according to claim 3, wherein the distance between the two points is a vertical height and the means for determining the set point comprises an artificial horizon.
5. A measurement instrument according to any preceding claim, wherein the rangefinder is an optical rangefinder.
6. A measurement device according to any one of claims 1-4, wherein the rangefinder is a laser rangefinder.
7. A measurement instrument according to claim 9, wherein the laser is an infra red laser.
8. A measurement instrument according to any preceding claim, wherein each measuring unit is provided with a camera.
9. A measurement instrument according to claim 8, wherein each cameras is orientated relative to a corresponding one of the rangefinders and records an image of the point at which the optical rangefinder is aimed.
10. A measurement instrument according to claim 9, as dependent on claim 5, wherein each camera is aligned parallel to a laser of its respective rangefinder.
11. A measurement instrument according to claim 9, as dependent on claim 5, wherein each camera is aligned offset to a calibrated distance relative to a laser of its respective rangefinder.
12. A measurement instrument according to any one of claims 8-11, wherein the instrument is provided with at least one display screen.
13. A measurement instrument according to claim 12, wherein the display screen comprises a first portion, which in use displays an image as viewed by the camera located within the first measuring unit, a second portion, which in use displays an image as viewed by the camera located within the second measuring unit and a third portion which in use displays data from the processor.
14. A measurement instrument according to any preceding claim, wherein the processor produces an output comprising the measured distance and angles between the two points and the date and time at which the measurement was recorded.
15. A measurement instrument according to claim 14, as dependent on any one of claims 8-1 1, wherein the output comprises an image as produced by each camera.
16. A measurement instrument according to any preceding claim, wherein the processor can take multiple measurements relative to a fixed reference point.
17. A measurement instrument according to any preceding claim, wherein the instrument further comprises a GPS unit.
18. A method of measuring the distance and/or angle between two points, the method comprising: using a rangefinder to measure the distance to a first one of the points; using an angle measurement device to determine the angle of rotation required to move the rangefinder from its starting position to the first one of the fixed points; storing the data relating to the first one of the fixed points; using the rangefinder to measure the distance to a second one of the fixed points; using an angle measurement device to determine the angle of rotation required to move the rangefinder from its starting position to the second one of the fixed points; storing the data relating to the second one of the fixed points; and transferring the data relating to the first and second fixed points to a processor and calculating the distance between the two fixed points.
19. A method according to claim 18, wherein a first rotatable measuring unit comprising a first rangefinder and a first angle measurement device measures the data relating to the first one of the points and a second rotatable measuring unit comprising a second rangefinder and a second angle measurement device measures the data relating to the second one of the points.
20. A method according to claim 18 or claim 19, wherein the angle of rotation of the first and second angle measurement devices is measured relative to a line perpendicular to both of the points.
21. A method according to any one of claims 18-20, wherein the rangefinder is an optical rangefinder.
22. A method according to any one of claims 18-20, wherein the rangefinder is a laser rangefinder.
23. A measurement instrument substantially as hereinbefore described with reference to the accompanying drawings.
24. A method substantially as hereinbefore described with reference to the accompanying drawings.