GB2369435A

GB2369435A - Apparatus for marking or surveying an area

Info

Publication number: GB2369435A
Application number: GB0028526A
Authority: GB
Inventors: Richard John Davis; Kevin Roy Welford; Keith Trafford; David Peter Henry Smith
Original assignee: FLEET; INFINITY SQUARED Ltd
Current assignee: FLEET; INFINITY SQUARED Ltd
Priority date: 2000-11-22
Filing date: 2000-11-22
Publication date: 2002-05-29
Also published as: GB0028526D0

Abstract

A control unit 1 has two satellite units 3 and 5 connected by way of elongate members 7 and 9 of variable length. Each elongate member may have an optically encoded portion to enable the length of the member (and the distance of the satellite from the control unit) to be determined. The optical encoding may be in the form of black and white transverse stripes or alternatively a series of holes may be present in the elongate member. The optical markings may be read by a sensor such as laser diode (25, figure 2) and detector (27). The length-determining means may alternatively consist of a magnetically encoded tape, an electrically conductive member, or a shaft encoder. The control unit may include a temperature monitoring means to determine ambient temperature and allow compensation to be made for any contraction or expansion experienced by the elongate member. The elongate members can be dispensed from and retracted into a housing 15 of the control unit by means of a reel. The reel may have a braking mechanism and a tensioning mechanism to control the elongate members.

Description

APPARATUS FOR USE IN SETTING OUT AN AREA TO BE MARKED OR FOR SURVEYING AN AREA This invention relates to an apparatus suitable for use in setting out an area to be marked, for example with lines or a graphical symbol such as a logo, or for surveying an area. The area might be, for example, a sports pitch or a car park.

It is conventional practice when setting out a sports pitch or the like to begin at a suitable point, such as a corner of the pitch, and mark out with string or the like the lines to be painted. Lines intended to be at right angles to one another are determined with the aid of a right angle triangle of suitable size and/or by measuring the sides of a triangle incorporating the right angle lines to check the ratios 3: 4: 5. The lengths of the various lines of a sports pitch, or the ranges thereof, are generally defined in the rules and are often presented in the form of an annotated plan, while the lines of a car park, for example, are generally marked out graphically on a scale plan. Logos can be marked or painted with the aid of templates, but this requires the template to be made off-site and transported to the pitch or the like in order that workers can apply paint to the playing or like surface through and/or around the template.

Although a sports pitch generally only needs to be set out once each season (with the lines subsequently being overmarked), it can take several workers a number of hours to mark out each pitch. This can impose significant pressures and costs on an organisation, such as a municipal council or contractor, that may have a significant number of pitches to mark in a relatively short time at the beginning of each season. It would therefore be of great help to have some means by which at least the major points of a sports pitch could be identified in order to assist marking out the pitch. Similarly, it would save a great deal of time if at least the major points of a car park or other graphical plan (such as a logo) could be identified in order to assist marking out.

It is therefore an object of the present invention to provide an apparatus suitable for use in setting out an area to be marked or for surveying an area.

According to the present invention there is provided an apparatus suitable for use in setting out an area to be marked or for surveying an area, the apparatus comprising: a primary unit and first and second secondary units each connected to the primary unit by an elongate member of variable length; and

means for determining the length of the elongate member between the primary unit and each of the first and second secondary units.

The apparatus may include means, such as a tripod and/or means for insertion into the ground, for mounting one or more of the primary and/or first and/or second secondary units in a stable manner relative to a ground surface.

The apparatus may include, for one or more of the primary and/or first and/or second secondary units, a means for guiding a marker into a ground surface at a predetermined location relative to the unit.

The elongate member may comprise an optically encoded member. The optical coding may comprise regularly spaced markings, such as stripes of different colours (for example black and white) or apertures, along the length of the elongate member. The optical codings may be spaced from 0.1 to 100 mm, preferably 1 to 10 mm and most preferably 1 to 5 mm apart. The primary unit may incorporate sensor means for detecting the optical coding as it passes the sensor as a result of the length of the elongate member between the primary unit and one or more of the secondary units changing. The sensor may incorporate a laser emitter and corresponding detector.

Alternatively or additionally, the elongate member may comprise a magnetically encoded member. The magnetic coding may comprise regularly spaced magnetised, or differentially magnetised, regions. The magnetic codings may be spaced from 0.1 to 100 mm, preferably 1 to 10 mm and most preferably 1 to 5 mm apart. The primary unit may incorporate sensor means for detecting the magnetic coding as it passes the sensor as a result of the length of the elongate member between the primary unit and one or more of the secondary units changing. The sensor may comprise a Hall effect or Giant magnetorestrictive sensor.

Additionally, or as a further alternative, the elongate member may comprise an electrically conductive member and the primary unit may incorporate time domain reflectometer means for determining the length of the electrically conductive member between the primary unit and one or more of the secondary units.

Additionally, or as a further alternative, the length of the elongate member dispensed and/or retracted may be determined with a shaft encoder or the like.

The elongate member may comprise a plurality of elongate components, such as a first component incorporating coding and a second component possessing desired physical properties, such as low and/or reproducible strain (stretch).

The elongate member may be mounted on rotatable storage means, such as a reel or the like, within the primary unit and/or within one or more of the secondary units. Each storage means may be provided with braking means to slow movement of the elongate member into and/or out of the primary unit. The storage means may be provided with tensioning means for adjusting the location of the storage means so as to apply a predetermined tension to the elongate member. Means may be provided for rotating the storage means so as to extend and/or retract the elongate member.

The primary unit may incorporate temperature monitoring means for determining ambient temperature so as to compensate for expansion and/or contraction of the elongate member.

The primary unit may incorporate control means for monitoring the length of the elongate member between the primary unit and one or more of the secondary units. The control means may incorporate means for storing and/or reading data relating to the area to be marked. Alternatively or additionally, the primary unit may incorporate means, such as a keypad or the like, for manually entering a desired length of the elongate member between the primary unit and one or more of the secondary units. The primary unit may incorporate a display for guiding and/or informing the user of the lengths of the

elongate members and/or the status of the area being marked. The present invention provides an apparatus for use in setting out an area to be marked, which apparatus is inexpensive yet accurate, allowing an area to be marked out by a single person and more quickly than hitherto. The apparatus is light and portable and may be hand held or attached to the user by means of a belt or the like or may be mounted on suitable wheels or the like.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a diagrammatic illustration of one embodiment of an apparatus according to the present invention for use in setting out an area to be marked; Figure 2 is a cross-sectional view of part of the apparatus of Figure 1 in more detail; Figure 3 is a plan view corresponding to Figure 2; and Figure 4 shows diagrammatically how the apparatus of Figures 1 to 3 can be used to mark out an area in the form of a sports pitch.

The apparatus shown in Figures 1 to 3 comprises a main control unit 1 (primary unit) and two satellite, or terminal, units 3 and 5 (secondary units) which are each connected to the main unit 1 by way of an elongate member 7 and 9, respectively.

Each satellite unit 3,5 includes means for mounting the satellite unit in a stable manner relative to a ground surface, such as a tripod 11, and means 13 for guiding marking means, such as a pole or post, for insertion into or on the ground surface at a predetermined location relative to the satellite unit.

Each elongate member 7,9 comprises an optically encoded tape to enable the precise length of the tape to be determined, and therefore the precise distance of the satellite unit from the main control unit 1 to be determined. The tape 7,9 clearly needs to be able to support an optical coding means and also to display suitable physical properties, such as low stretch and low weight over substantial distances, such as 200 m or more.

To this end, the tape 7,9 may comprise multiple components such as a first component bearing the necessary optical markings, such as transverse or circumferential differentially coloured stripes or the like, at predetermined intervals, and a second component possessing low and/or reproducible strain (stretch) characteristics

and low density. For example, the first component may be encapsulated within the second component or vice versa. The main control unit 1 comprises a number of components mounted within a housing 15. The housing is mounted on a suitable stabilising mechanism, such as a tripod 17, and is provided with means 19 for guiding marking means, such as a pole or post, for insertion into or on the ground surface at a predetermined location relative to the main control unit.

As best shown in Figure 2, optical markings 21,23 on the tape 7,9 may be in the form of sequential coloured, e. g. black and white, transverse stripes which may each have a suitable width, such as 0.1 to 100 mm, preferably 1 to 10 mm and most preferably 1 to 5 mm or other suitable dimension depending on the particular application and the accuracy required. Alternatively, the tape or other elongate member may be formed with holes (not shown) of a suitable size at predetermined spacings. In either case, as shown diagrammatically in Figure 3 a suitable sensor would comprise a laser diode 25 and a detector 27 for detecting reflected or transmitted laser radiation as the optical markings pass the sensor. The sensor 25,27 is provided within the housing 15 and is responsive to the optical markings on the tape so as to count the number of markings that pass the sensor. More complex optical

patterns may be provided to convey further information such as the direction of travel of the tape.

The optical markings can be detected by the sensor and counted out or in to determine the length of tape between the main control unit and the satellite unit as will be described in more detail hereinafter.

The two tapes 7,9 are each stored on any suitable dispenser within the housing 15, such as a reel 29 which is rotatable to dispense and retract the tape as required.

Each reel 29 is provided with a braking means 31 (shown diagrammatically) in order to slow and stop rotation thereof when a desired length of tape has been dispensed or retracted and with a tensioning system 33 (shown diagrammatically) to ensure the tension applied to each tape is constant in order that any stretch of the tapes is reproducibly compensated (or proportionally constant). The tensioning system 33 allows the reels 29 to move in a generally horizontal plane as indicated by the arrows in Figure 2 so as to allow final adjustment of the reels 29 to a location in which a predetermined tension is applied to each of the tapes and therefore allows final adjustment of the guide means 19 which is movable with the reels 29. The reels 29 may be rotatable by hand and/or may be provided with means (not shown), such as a low-power electric motor or a spiral spring arrangement, for automatically

dispensing and/or retracting the tapes 7, 9. Thus the length of each tape can be varied. The main control unit 1 may be provided with temperature monitoring means (not shown), such as a thermocouple or temperature dependent resistor, for determining ambient environmental temperature, so as to compensate for any temperature-dependent expansion or contraction of the tape and/or to compensate for any temperature-dependent change in the stretch of the tape.

The main control unit 1 also incorporates control means, such as a microprocessor 35, for monitoring the length of each tape between the main control unit and each of the satellite units. The control means may incorporate data relating to the area to be marked out, for example stored in digital form either in a memory 37 in the control means itself and/or readable by the control means from an external data storage device (not shown), possible replaceable, such as a floppy disk or memory module such as a smart card. Alternatively, the control means may be provided with means for entering manually the required length of each tape to be beyond the sensor (s) for each step of the marking-out process.

Where the data relating to the area to be marked out is stored in the control means or provided by an external memory means, the control means incorporates a suitable

display 39 for presenting the user with a menu of commands available and steps required in order to conduct the marking-out procedure and for informing the user of the status of the apparatus. Alternatively, where the data for each step is to be entered manually, the user will require the necessary dimensions for each step, for example written on a suitable instruction sheet, which dimensions are entered manually into a keypad or the like (not shown) provided on the main control unit 1.

The main control unit 1 may incorporate means permitting the apparatus to be used for marking out only a predetermined number or areas. This may comprise, for example, a code to be entered or a (further) smart card to be used. The apparatus will then require to be reset, for example by entering a suitable code, before it can be used further or by requiring the purchase of an additional user smart card. In this way the apparatus can be employed on a"pay-per-use"basis.

The apparatus is capable of considerable accuracy, for example an error of about 10 mm in 150 m is readily attainable.

Use of the apparatus will be explained with reference to the marking out of a football pitch, although this will be understood merely to be representative of marking out any chosen area.

In use of the apparatus with the data relating to the pitch to be marked out stored in the control means or provided by an external memory means, the type of area to be marked out is selected by the user from a menu of options presented on display 39 of the main control unit 1.

One satellite unit 3 is positioned and firmly mounted in place at a first predetermined datum location as instructed by the main control unit 1 on the display 39 thereof and the other satellite unit 5 is positioned at a second predetermined datum location as instructed by the main control unit 1 on the display thereof. In the case of a football pitch, the first and second datum locations may be a specific one of each pair of pre-existing goal post sockets or corner post positions as shown in Figure 4.

Alternatively, where there are no pre-existing sockets or positions, the second datum location is established by dispensing a predetermined length of tape from the main control unit to the satellite unit 3 with the satellite unit 5 retained with the main unit, and moving the combined main unit and second satellite unit to a desired location, or a location selected from a range of alternatives, at which the tape is pulled tight and the automatic tensioning system 33 is activated so as to locate the guide means 19 of the main unit at a second datum point which can be identified with a peg or the like. The second satellite unit 5 is then located and firmly mounted in place at the second datum location.

With the two satellite units 3 and 5 in place, the main control unit 1 is separated from the second satellite unit 5 and the pitch can be marked out step-by-step by following instructions displayed on the main control unit 1.

The tapes 7 and 9 are dispensed from or retracted into the housing of the main unit 1 and locked in place with braking means 31 such that each tape is of a predetermined length for the main control unit 1 to triangulate at a position corresponding to a desired location on the football pitch, such as that shown at 41 on Figure 4. The main unit 1 is then moved by the user such that the two tapes are pulled taut, the automatic tensioning system 33 is activated to adjust the position of the guide means 19 of the main control unit 1 if necessary, and a marker applied through the guide means 19 to mark an appropriate point on the pitch surface.

The remaining points to be identified are subsequently located and marked in turn under the direction of the main control unit 1 in order that the various markers can be applied in a time-efficient manner. For each marker, the tapes are metered out and the braking means 31 is applied, the main control unit is moved such that each tape 7 and 9 is taut, the automatic tensioning system 33 is actuated and any adjustment of the guide means of the main control unit is applied before a marker is inserted into the pitch surface through the guide means 19. Thus the entire pitch

can be marked out with pegs or the like, which pegs can subsequently be connected with string or the like and lines or other marking can be applied in a conventional manner.

It will be appreciated that other forms of optically encoded tape can be employed if desired, and that the elongate member may comprise or incorporate alternative means for enabling the precise length thereof to be determined. If desired, these alternatives may be employed in combination. Indeed, the elongate member may not be in the form of a flat tape, but may have an alternative configuration such as a thread, string or wire which may, for example, be more or less cylindrical.

For example, as an alternative or in addition, the elongate member may comprise or incorporate a magnetically encoded tape, the tape being provided with regularly spaced magnetised, or differentially magnetised, transverse stripes or other regularly spaced regions which can be read by a suitable detector, such as a Hall effect sensor or a GMR (Giant magnetorestrictive) sensor. In such a case the tape or the like can be provided with magnetic north and south poles at regular predetermined spacings, such as 1 to 5 mm or other suitable spacing depending on the particular application and the accuracy required. The poles can be detected by the sensor and counted out or in to determine the length of tape beyond the sensor. More complex magnetic patterns may be provided to convey further

information such as the direction of travel of the elongate member.

Additionally or as a further alternative, the elongate member may comprise an electrically conductive member, such as a conducting cable, and the length of the cable beyond the main control unit can be determined by time domain reflectometry (TDR). Time domain reflectometry is a well known technique for determining, for example, the location of a fault in a cable, and involves transmitting a short pulse, such as a DC pulse or an AC pulse having a ramped increase in frequency, along the cable from within the main control unit and examining the reflected pulse (reflected from the corresponding terminal unit) received back at the main control unit. The distance travelled can be determined in known manner from the time elapsed and/or from changes in the waveform of the reflected pulse as compared with the transmitted pulse. Time domain reflectometry has the advantage that the elongate member does not need to be encoded with means for determining the length thereof.

Additionally or as a further alternative, a shaft encoder or the like may be employed in relation to each elongate member to measure the length of the elongate member dispensed and/or retracted.

Claims

CLAIMS 1. An apparatus suitable for use in setting out an area to be marked or for surveying an area, the apparatus comprising : a primary unit and first and second secondary units each connected to the primary unit by an elongate member of variable length; and means for determining the length of the elongate member between the primary unit and each of the first and second secondary units.
2. An apparatus as claimed in claim 1 and including means for mounting one or more of the primary and/or first and/or second secondary units in a stable manner relative to a ground surface.
3. An apparatus as claimed in claim 2, wherein the mounting means comprises a tripod.
4. An apparatus as claimed in claim 2 or 3, wherein the mounting means comprises means for insertion into the ground.
5. An apparatus as claimed in any preceding claim and including, for one or more of the primary and/or first

and/or second secondary units, a means for guiding a marker into a ground surface at a predetermined location relative to the unit.
6. An apparatus as claimed in any preceding claim, wherein the elongate member comprises an optically encoded member.
7. An apparatus as claimed in claim 6, wherein the optical coding comprises regularly spaced markings along the length of the elongate member.
8. An apparatus as claimed in claim 7, wherein the markings comprise stripes of different colours.
9. An apparatus as claimed in claim 6, wherein the optical coding comprises regularly spaced apertures, along the length of the elongate member.
10. An apparatus as claimed in any one of claims 6 to 9, wherein the optical codings are spaced from 0.1 to 100 mm apart.
11. An apparatus as claimed in claim 10, wherein the optical codings are spaced from 1 to 10 mm apart.
12. An apparatus as claimed in claim 11, wherein the optical codings are spaced from 1 to 5 mm apart.
13. An apparatus as claimed in any one of claims 6 to 12, wherein the primary unit incorporates sensor means for detecting the optical coding as it passes the sensor as a result of the length of the elongate member between the primary unit and one or more of the secondary units changing.
14. An apparatus as claimed in claim 13, wherein the sensor incorporates a laser emitter and corresponding detector.
15. An apparatus as claimed in any preceding claim, wherein the elongate member comprises a magnetically encoded member.
16. An apparatus as claimed in claim 15, wherein the magnetic coding comprises regularly spaced magnetised, or differentially magnetised, regions.
17. An apparatus as claimed in claim 16, wherein the magnetic codings are spaced from 0.1 to 100 mm apart.
18. An apparatus as claimed in claim 17, wherein the magnetic codings are spaced from 1 to 10 mm apart.
19. An apparatus as claimed in claim 18, wherein the magnetic codings are spaced from 1 to 5 mm apart.
20. An apparatus as claimed in any one of claims 15 to 19, wherein the primary unit incorporates sensor means for detecting the magnetic coding as it passes the sensor as a result of the length of the elongate member between the primary unit and one or more of the secondary units changing.
21. An apparatus as claimed in claim 20, wherein the sensor comprises a Hall effect sensor.
22. An apparatus as claimed in claim 20, wherein the sensor comprises a Giant magnetorestrictive sensor.
23. An apparatus as claimed in any preceding claim, wherein the elongate member comprises an electrically conductive member and the primary unit incorporates time domain reflectometer means for determining the length of the electrically conductive member between the primary unit and one or more of the secondary units.
24. An apparatus as claimed in any preceding claim and including a shaft encoder or the like for determining the length of the elongate member dispensed and/or retracted.
25. An apparatus as claimed in any preceding claim, wherein the elongate member comprises a plurality of elongate components.
26. An apparatus as claimed in claim 25, wherein the elongate member comprises a first component incorporating coding and a second component possessing desired physical properties.
27. An apparatus as claimed in any preceding claim, wherein the elongate member is mounted on rotatable storage means within the primary unit and/or within one or more of the secondary units.
28. An apparatus as claimed in claim 27, wherein the rotatable storage means comprises a reel.
29. An apparatus as claimed in claim 27 or 28, wherein each storage means is provided with braking means to slow movement of the elongate member into and/or out of the respective unit.
30. An apparatus as claimed in any one of claims 27 to 29, wherein the storage means is provided with tensioning means for adjusting the location of the storage means so as to apply a predetermined tension to the elongate member.
31. An apparatus as claimed in any one of claims 27 to 30, wherein means is provided for rotating the storage means so as to extend and/or retract the elongate member.
32. An apparatus as claimed in any preceding claim, wherein the primary unit incorporates temperature monitoring means for determining ambient temperature so as to compensate for expansion and/or contraction of the elongate member.
33. An apparatus as claimed in any preceding claim, wherein the primary unit incorporates control means for monitoring the length of the elongate member between the primary unit and one or more of the secondary units.
34. An apparatus as claimed in claim 33, wherein the control means incorporates means for storing and/or reading data relating to the area to be marked.
35. An apparatus as claimed in claim 33 or 34, wherein the primary unit incorporates means for manually entering a desired length of the elongate member between the primary unit and one or more of the secondary units.
36. An apparatus as claimed in claim 35, wherein the manual entering means comprises a keypad.
37. An apparatus as claimed in any one of claims 33 to 36, wherein the primary unit incorporates a display for guiding and/or informing the user of the lengths of the elongate members and/or the status of the area being marked.
38. An apparatus suitable for use in setting out an area to be marked or for surveying an area substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.