GB2275114A - Metal-detecting unit for securing to vehicle - Google Patents

Abstract

The unit comprises a metal-detecting coil 10, control and indicator means for the coil and motorised means 11, 15 to move the metal-detecting coil transversely across a direction of motion of the vehicle. The unit fits by dovetails into a bracket 26, 27 mounted on the vehicle. The coil 10 is supported by a nylon tube 12 fitted into aluminium tube 11. The height of the tube 11 is adjustable by bracket 17, 19, 20, 21, and the detector assembly is scanned transversely across the direction of motion of the vehicle by motor 15. The height of the coil 10 above the ground may be measured and controlled. <IMAGE>

Description

Metal-Detector Unit.

The present invention relates to metaldetectors and particularly to mobile metaldetecting units.

The use of metal-detectors to find buried items such as coins or historical artefacts is a popular pastime. Typically, small, metaldetector coils are located at the end of a stem, the other end of which is held by a person hunting for metal, and swung slowly through an arc in front of the hunter as he walks forward over a piece of land which is to be scanned for metal. More powerful metaldetectors may also be employed in this fashion for commercial purposes, for example.

In certain circumstances it is desirable to be able to scan an area with a metaldetector without the need for a person to hold the stem, and manually scan whilst walking.

For example, when a large area is to be scanned, the manual scanning described above may become too tiring for a single person to achieve. Also, disabled people may find such activity difficult or impossible and so be denied access to a rewarding hobby.

Metal-detectors have been fixedly mounted upon vehicles, notably on rugged off-road vehicles for searching open areas of land. However there are problems with such methods of searching in that the engines, and especially the transmission systems, of the vehicles can affect the operation of the detector.

Specialised deep-scanning detectors may be used to overcome this problem but they are not suitable for use in all circumstances and would not normally be used by an amateur hunter.

It is an object of the present invention to provide an improved form of metal-detecting unit which overcomes some, at least, of the above problems.

According to the invention, a metaldetecting unit adapted to be secured to a vehicle comprises a metal-detecting coil, control and indicator means for said coil and motorised means to move said metal-detecting coil transversely across a direction of motion of said vehicle.

The metal-detecting coil may be of any suitable size and weight which may be conveniently borne by the motorised movement means. Preferably the coil is a relatively lightweight, compact unit of the type commonly used by amateur metal-hunters.

Advantageously, a coil is provided with means for removably attaching the coil to the motorised means. In this way, a metal-hunter may use his metal-detecting coil in the motorised form of the invention or as a handheld apparatus, depending upon the task involved.

Although any vehicle may be used which is suitable for use on the type of terrain to be scanned, it is preferable to use a vehicle having a hydrostatic transmission which has an infinitely variable drive. This type of vehicle emits less engine noise and is much less likely to interfere with the operation of the metal-detecting coil than a vehicle with a standard transmission having gears. In many situations where rough or undulating terrain is to be scanned, the most preferred type of vehicle is the small, low single-seat tractor which is often used with grass-cutting equipment, for example. Such vehicles are usually provided with a suspension system which has been designed to keep ground-following equipment within a pre-set distance of the ground as the vehicle moves.

The motorised means for moving the coil transversely across the direction of movement of the vehicle may, in one form, drive a carriage along a track mounted transversely across the vehicle, the coil being directly or indirectly attached to the carriage.

Preferably the coil is suspended from the carriage via a stem. Most preferably the carriage, track and stem are designed not to interfere with the operation of the metaldetecting coil by selecting non-conducting materials for their construction or by providing shielding between the coil and a source of interference.

In an alternative and preferred form the motorised means comprises an elongate stem, coupled at one end to a motor so that it may pivot in a generally horizontal plane around the motor linkage. The metal-detecting coil is mounted at the other end of the stem so as to be generally parallel to the ground. The motor drives the stem through an arc both clockwise and anticlockwise. Thus a scanning movement of the coil is achieved which is similar to the action imparted manually by a metal-hunter using a hand-held metal-detecting unit. The stem is driven through an arc preferably in the range 70 - 1800, and most preferably in the range of about 90 - 1200 In a preferred form, the arc through which the stem is driven may be varied by the user according to his requirements.Preferably a portion of the stem adjacent to the coil is formed of a non-conducting material such as a plastics material to minimise the interference with the operation of the metal-detector which a wholly metal stem would cause.

The speed at which the stem is driven in an arc to scan the coil along the ground may be variable. In a preferred form of the invention, one of two scanning speeds may be selected by the user depending upon the circumstances of use.

The height of the coil above the ground may be variable. In one form of the invention the angle of the stem from horizontal may be adjustable to provide any of several scanning heights.

As an optional feature, the coil may be provided with a sensing device for determining the distance between the ground and the coil.

The sensing device, which may be an infra-red or laser rangefinder for example, may provide information to a device which may raise or lower the metal-detecting unit or a part thereof to maintain a constant distance between the coil and the ground.

The metal-detector and motorised means are mounted upon a vehicle when in use. Preferably the motor unit is mounted upon a vehicle in such a way as to be easily mounted upon and removed from the vehicle so that the metaldetector and/or vehicle may be used for other purposes. In one form, the mounting may be achieved by means of a bracket secured to the motorised metal-detector having grooves or a dovetail which may engage in complementary grooves or a dovetail located on a surface of a bracket secured to the vehicle. Optionally, the relative vertical position between the brackets may be adjusted to enable the metaldetecting unit to be raised or lowered relative to the vehicle by sliding the engaging dovetails relative to one another. This may be achieved by providing a pulley system in the mounting, a toothed track which may be moved by engagement with a driven cog or in other ways.

Optionally, the motorised metal-detector may be provided with means to lift the coil away from the ground when not in use, for example whilst being transported to or from the area of land to be scanned. This may be achieved by providing a pivotal attachment between the metal-detector and the vehicle or between a stem supporting the coil and the motorised means The motorised means for moving the coil preferably comprises an electric motor. The electric motor may be powered by the vehicle's engine via the alternator, if present. When electric vehicles are used then the power for the motor would most conveniently be drawn from the vehicle's own electricity supply e.g. a battery.

A preferred embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawings which are: Fig.l, a view of the motorised metal-detecting unit, partly in section, in elevation from the side, and Fig.2, a plan view of the motorised metal-detecting unit.

In Fig.l, a coil 10 is pivotally attached to a cylindrical nylon tube 12 which is inserted into an end of a tubular aluminium stem 11 so as to form a close fit. This arrangement permits the distance between the coil 10 and the further end of the stem 11 from the coil to be adjusted by varying the extent to which the tube 12 is pushed into stem 11. The pivotal connection between the coil 10 and tube 12 allows the angle of the coil relative to the stem to be selected and the connection may then be- tightened by means of e.g. a wing nut. The stem 11 is typically between lm and 1.5m long.

Tube 12 is formed of nylon so as to minimise interference with the metal-detecting function of the coil caused by the presence of the stem.

The stem 11 is pivotally connected at 13 to a linkage system 14 which is in turn connected to be driven by an electric motor 15. The pivot at 13 allows movement of the stem in a vertical plane, so that the height of the end of the stem above the ground may be adjusted and so that it may allow the stem to move to accommodate unevenness in the ground encountered by the coil. A further pivot at 22 forms a part of the linkage to the motor 15 and this allows movement of the stem 11 in a horizontal plane to scan the coil from side to side in an arcuate path.

The motor 15 is located within a housing 16, and is conveniently of the type which may be used to drive vehicle windscreen wipers.

The motor is powered by a vehicle engine via the vehicle alternator but the wiring has been omitted from the drawings for clarity.

A load-bearing support stem 17 extends between a pivot point 18 and the stem 11. The stem 11 is fastened by means of a wing nut 19 to a bracket 20 which extends from the support stem 17. The angle between stem 11 and support stem 17 may be adjusted by fastening the stem 11 to a different point on bracket 20 by choosing an appropriate hole 21 through which to place the wing nut 19. The stem 11 need not be fastened to the stem 17; it may simply rest upon the support stem, preferably in a recess located at the end of the support stem and shaped so as to receive the stem. By means of the pivotal attachment of the support stem at 18 to a support bracket 23 the support stem may pivot in a horizontal plane to follow the driven scanning movement of the stem 11.

The housing 16 and bracket 23 are mounted on a plate 24 which, by means of cooperating dovetail connections 25, may be removably mounted upon a bracket 26. Bracket 26 is mounted at a pivot 27 on a vehicle (not shown).

The pivotal mounting at 27 enables the whole metal-detecting unit to be lifted upwards for transport to and from the site to be scanned.

In use, the unit is mounted upon a lawntractor, for example, by engaging the dovetail guides of the plate 24 with those of bracket 26 which may be more permanently mounted to the tractor at 27. A cable which connects the coil 10 to control and indicating equipment is then clipped to the side of the stem and run to a control box which may be located in any position which is convenient for the user, e.g.

it may be located within the vehicle on which the unit is mounted. Likewise, the controls for operating the unit may conveniently be located within the vehicle. The cabling is not shown in the drawings.

The user may then operate the motor 15 to scan the coil from side to side in an arc around the pivot 22 as shown in Fig.2 as he drives the vehicle forward over the land which is to be searched. In this way, a strip of land may be searched which is as wide as the scanning arc selected allows. It is therefore much less strenuous to search a piece of land by using the metal-detecting unit of the invention than it would be using a hand-held metal-detector.

Claims (18)

1. A metal-detecting unit, adapted to be secured to a vehicle, comprising a metaldetecting coil, control and indicator means for said coil and motorised means to move said metal-detecting coil transversely across a direction of motion of said vehicle.

2. A. metal-detecting unit as claimed in claim 1, wherein said motorised means drives a carriage along a track mounted transversely across the vehicle, the coil being directly or indirectly attached to said carriage.

3. A. metal-detecting unit as claimed in claim 1, wherein said motorised means comprise an elongate stem coupled at one end to a motor in such a way that it may pivot in a generally horizontal plane around the motor linkage.

4. A metal-detecting unit as claimed in claim 3, wherein the stem is driven by the motor through an arc in the range seventy to one hundred and eighty degrees.

5. A metal-detecting unit as claimed in either claim 3 or claim 4, wherein the stem is driven by the motor through an arc in the range of ninety to one hundred and twenty degrees.

6. A metal-detecting unit as claimed in any of claims 3-5 wherein a portion of the stem adjacent to the coil is formed from a non-conducting material.

7. A metal-detecting unit as claimed in any of the preceding claims, wherein said unit may be readily mounted on and removed from a vehicle.

8. A metal-detecting unit as claimed in any of the preceding claims, wherein the height of the coil above the ground may be varied.

9. A metal-detecting unit as claimed in any of the preceding claims, wherein the coil is provided with a sensing device for determining the distance between the ground and the coil.

10. A metal-detecting unit as claimed in claim 9, wherein the sensing device is an infra-red or laser rangefinder.

11. A metal-detecting unit as claimed in claim 9 or claim 10, wherein the sensing device provides information to a device for raising and lowering the metal-detecting unit or a part thereof, thereby to maintain a constant distance between the coil and the ground.

12. A metal-detecting unit as claimed in any of the preceding claims, wherein the speed of movement of the coil is variable.

13. A metal-detecting unit as claimed in any of the preceding claims, wherein means are provided to mount said unit on a vehicle, said means comprising a bracket secured to the metal-detecting unit having a dovetailed surface adapted to cooperate with a corresponding dovetailed surface of a bracket secured to the vehicle.

14. A metal-detecting unit as claimed in claim 13 wherein means are provided to adjust the relative vertical positions of the brackets by sliding the engaging dovetails relative to one another.

15. A metal-detecting unit as claimed in any of the preceding claims, wherein means are provided to raise the coil away from the ground.

16. A metal-detecting unit as claimed in claim 15, wherein said means comprise a pivot between the unit and the vehicle.

17. A metal-detecting unit according to any of the preceding claims wherein said motor is an electric motor.

18. A metal-detecting unit substantially as described herein with reference to and as shown in the accompanying drawings.