Metal detector mounting apparatus

Abstract

A metal detector comprises a coupling (20), an extension member (30) extending away from the coupling, and a mount (60) attached to a distal end of the extension member. The mount is configured to receive at least one search coil (50). The mount is configured to rotate the at least one search coil in a respective circular path about an axis of rotation and / or to move the at least one search coil along a combined first arced path and a second arced path.

Description

Metal Detector Mounting ApparatusField of the Invention

[0001] The invention relates to a metal detector mounting apparatus.Background

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[0003] Metal detecting using conventional means involves a handheld metal detector, comprising a search coil fixed to an end of a pole, with a handle and feedback and control unit at the other end. The operator holds the handle and sweeps the search coil over the ground. The feedback and control unit provide readings to the operator when metallic objects are detected within the range of the search coil.

[0004] Searching a large area is time consuming and an area can be sparsely populated with metal objects. An improvement in the rate at which metal objects within a large area can be detected is desirable.

[0005] GB22751 14 provides a search coil that is able to swing back and forth in an arc so that movement of the search coil is similar to that which the search coil of a handheld metal detector can move. While it alleviates manual movement of the search coil, such that an operator is not as easily tired, there is no gain in the rate at which metal objects within a large area can be detected as the movement of the search coil is essentially no different from a traditional handheld metal detector.

[0006] It is against this background that the invention is presented.

[0007] Throughout the specification unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0008] Throughout the specification unless the context requires otherwise, the word “include” or variations such as “includes” or “including”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0009] Throughout the specification unless the context requires otherwise, the term “search coil” is to be taken to mean a transmitter coil and receiver coil, typical of the arrangement known in the art, as used in handheld metal detectors.Summary of Invention

[0010] Unless the contrary is apparent, embodiments of the principal aspects, and any of those described below, may comprise or incorporate, either individually or in combination, any of the following features.

[0011] According to an aspect of the invention, there is provided a metal detector comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive at least one search coil, and wherein the mount is configured to rotate the at least one search coil in a respective circular path about an axis of rotation.

[0012] In an embodiment, the axis of rotation is configured to move in a swing path about the coupling, such that the movement of the least one search coil is a combination of the respective circular path and the swing path. In an embodiment the swing path may be elliptic or otherwise comprise an arc.

[0013] In an embodiment, the coupling may comprise or is connected to a handle. In an embodiment, the coupling is attached to a wearable or handheld item.

[0014] According to an aspect of the invention, there is provided a mounting apparatus for a metal detector, the mounting device comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive at least one search coil of the metal detector, and wherein the mounting apparatus is configured to move the at least one search coil along a combined first arced path and a second arced path.

[0015] In an embodiment, the coupling is configured to attach to a vehicle.

[0016] In an embodiment, the coupling is configured to attach to a tow hitch.

[0017] In an alternative embodiment, the coupling is configured to be worn or held by an operator.

[0018] In an embodiment, at least one of the at least one search coil is offset from the mount. In an embodiment, the offset is substantially horizontal when in use.

[0019] In an embodiment, the first arced path describes an arc around the mount.

[0020] In an embodiment, the second arced path describes an arc around the coupling.

[0021] In an embodiment, the mounting apparatus is configured to move the at least one search coil along a first arced path and is further configured to move the mount along a second arced path.

[0022] In an embodiment, the first arced path is around the mount.

[0023] In an embodiment, the second arced path is around the coupling.

[0024] In an embodiment, the first arced path comprises full rotation in a circle. In an embodiment, the second arced path oscillates through an incomplete rotation, for example, to swing back and forth. In an embodiment, the axis of rotation of the first arced path moved along the second arced path. In an embodiment, the centre of at least one of the least one search coil is offset from the axis of rotation.

[0025] In an embodiment, the mount is configured to rotate an attached search coil.

[0026] In an embodiment, the mount is configured to rotate an attached search coil in a plane generally parallel to the ground or a surface upon which the vehicle is located.

[0027] In an embodiment, the mount is configured to receive two search coils. In an embodiment, each of the two search coils is offset from the mount. In an embodiment, each of the two search coils is offset by a different distance from the mount. Alternatively, the search coils are offset by the same distance.

[0028] In an embodiment, a first of the search coils comprises different operating characteristics to a second of the search coils.

[0029] In an embodiment, the characteristics include the size of the search coils.

[0030] In an embodiment, the characteristics include an electrical property of the search coils, such as number of windings and / or inductance.

[0031] In an embodiment, the mount is configured to rotate the first search coil and the second search coil around each other.

[0032] In an embodiment, the mount is configured to move a plurality of search coils in a planetary rotating configuration.

[0033] In an embodiment, the mounting apparatus comprises a control unit, wherein the control unit is configured to be mounted proximal to an operator.

[0034] In an embodiment, the control unit is configured to control the movement of the at least one search coil.

[0035] In an embodiment, the control unit is configured to be mounted to the vehicle in view of an operator.

[0036] In an embodiment, the control unit is configured to control parameters of the mounting apparatus.

[0037] In an embodiment, the parameters include speed and / or extent of the movement along the arced path.

[0038] In an embodiment, the speed and / or extent of the movement along the arced path are adjusted according to the speed of the vehicle.

[0039] In an embodiment, the parameters include height of the mount relative to the ground.

[0040] In an embodiment, the parameters include speed of rotation of the at least one search coil.

[0041] In an embodiment, the parameters are adjusted according to the speed of the vehicle.

[0042] In an embodiment, the parameters are adjusted to optimize coverage of the surface area.

[0043] In an embodiment, the parameters include controlling the speed of movement along the arced path based on the speed of the vehicle.

[0044] In an embodiment, the parameters include controlling the speed of movement in an arc based on the diameter of the search coils.

[0045] In an embodiment, the control unit is configured to provide a target speed to an operator, where the target speed is based on the parameters of the mounting apparatus. The target speed is the speed at which the vehicle should be moved over the ground.

[0046] In an embodiment, the metal detector comprises a detector transceiver configured to operate the at least one search coil.

[0047] In an embodiment, the detector transceiver is configured to operate a plurality of search coils arranged in series. In an alternative embodiment, the detector transceiver is configured to operate a plurality of search coils arranged in parallel.

[0048] In an embodiment, the detector transceiver is mounted to the mounting apparatus.

[0049] In an embodiment, the detector transceiver is configured to provide detection information from the at least one search coil to an operator.

[0050] In an embodiment, the detector transceiver is configured to identify one or more locations at which the at least one search coil indicates that metal is present, and preferably to record the one or more locations.

[0051] In an embodiment, the detector transceiver is configured to provide an output, wherein the output comprises a map of area covered during travel of the vehicle, and locations of metal identified by the at least one search coil within the area.

[0052] In an embodiment, the mounting apparatus further comprises a first member comprising a first end and a second end, wherein the first end is attached to the coupling, and wherein the extension member is attached to the second end.

[0053] In an embodiment, the second end is higher than the first end when attached to the coupling.

[0054] In an embodiment, the mounting apparatus is configured to move the mount along the arced path.

[0055] In an embodiment, the mounting apparatus is configured to move the mount by moving the extension member relative to the coupling.

[0056] In an embodiment, the first member is adjustable in length, so that the height of the second end relative to the coupling is able to be altered.

[0057] In an embodiment, the first end of the first member is able to rotate relative to the second end.

[0058] In an embodiment, the first member comprises a rotational device, such as a motor, configured to impart rotational movement between the second end and the first end.

[0059] In an embodiment, the rotational movement causes the mount to move along the arced path.

[0060] In an embodiment, the arced path has a centre of rotation proximal to the first end of the first member.

[0061] In an embodiment, the arced path extends up to 30 degrees each side of a centre point, preferably up to 60 degrees, more preferably up to 90 degrees.

[0062] In an embodiment, the arced path extends entirely around the vehicle, and describes a full circle.

[0063] In an embodiment, the centre point of the circle is directly in front of the vehicle.

[0064] In an embodiment, the rotational device is a servo motor.

[0065] In an alternative embodiment, the extension member comprises a vehicle end, and the distal end, and wherein the extension member is pivotally attached at a pivot point to the second end of the first member.

[0066] In an embodiment, the pivot point is between the vehicle end and the distal end of the extension member.

[0067] In an embodiment, the mounting apparatus comprises a drive means attached to the vehicle end of the extension member.

[0068] In an embodiment, the drive means is configured to impart sideways movement to the vehicle end of the extension member, causing the distal end to move along a path.

[0069] In an embodiment, the drive means is configured to attach to a roof of the vehicle.

[0070] In an embodiment, the vehicle mount is configured to attach to a front of the vehicle.

[0071] In an embodiment, the mounting apparatus comprises an angular adjustment device configured to impart an angular movement of the extension member with respect to the first member.

[0072] In an embodiment, the angular movement enables height adjustment of the mount relative to the coupling or the vehicle.

[0073] In an embodiment, the extension member is adjustable in length.

[0074] In an embodiment, at least a portion of the extension member is non-metallic.

[0075] In an embodiment, the non-metallic portion of the extension member is toward the distal end.

[0076] In an embodiment, at least the distal end of the extension member is non-metallic.

[0077] In an embodiment, the at least one search coil is configured to operate at very low frequency (VLF), between 6kHz and 13kHz.

[0078] In an embodiment, the at least one search coil is configured to operate using pulse induction.

[0079] In an embodiment, at least one search coil is configured to operate at very low frequency (VLF), between 6kHz and 13kHz, and at least one other search coil is configured to operate using pulse induction.

[0080] According to an aspect of the invention, there is provided a mounting apparatus for a handheld metal detector having a search coil, the mounting device comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive the handheld metal detector, and wherein the mounting apparatus is configured to move the handheld metal detector so that the search coil moves along an arced path offset from the mount.

[0081] In an embodiment, the arced path is a circle. In an embodiment, there is a second search coil that moves in a second arced path. Preferably the second arced path is along a co-orbital path, substantially equidistant in both directions, with respect to the first search coil. In an embodiment, the mount is suspended by a suspension part of the extension member. In an embodiment, the suspension part is coupled to a beam part of the extension member.

[0082] In an embodiment, the extension member comprises a motor for rotating the search coils in the co-orbital path. In an embodiment, the motor is in the suspension part. In an embodiment, the motor connects to the mount by a drive shaft.

[0083] In an embodiment, the suspension part is detachable from the beam part. In an embodiment, the beam part connects via the coupling to a wearable item. In an embodiment, the coupling permits the beam part to pivot with respect to the wearable item. In an embodiment, the coupling is a swivel mechanism.

[0084] In an embodiment, the extension member comprises a wand member for causing the extension member to pivot with respect to the wearable item. In an embodiment, the wandmember is pivotably coupled to the first extension member. In an embodiment, the wand member comprises a handle. In an embodiment, the wand member comprises an arm brace.

[0085] In an embodiment, the wearable item is a back harness, that preferably comprises shoulder straps and a belly strap. In an embodiment, the coupling is located substantially around the shoulder blades / neck and the beam is curved over the position of the head of the wearer of the wearable item.

[0086] According to an aspect of the invention, there is provided a mounting apparatus for mounting a search coil of a metal detector to a vehicle configured to drive across a surface, wherein the mounting apparatus is configured to sweep the search coil along a path that combines a first arced movement of a centre of motion of a second arced movement during movement of the vehicle.

[0087] In an embodiment, the mounting apparatus comprises a mount, wherein the arced path is around the mount.

[0088] In an embodiment, a plurality of search coils are affixed to the mount.

[0089] In an embodiment, the at least one search coil is rotatably affixed to the mount.

[0090] In an embodiment, the mounting apparatus is configured to move the at least one search coil along a first arced path and is further configured to move the mount along a second arced path.

[0091] In an embodiment, the first arced path is around the mount, and the second arced path is around a coupling to the vehicle.

[0092] In an embodiment, either or both of the arced paths comprises full rotation in a circle.

[0093] In an embodiment, the arced path is defined to optimize coverage of surface area within a path of the vehicle.

[0094] In an embodiment, the arced path is defined to enable increased coverage of surface area when compared to a straight path.

[0095] In an embodiment, the path traverses side to side with respect to a direction of travel of the vehicle.

[0096] In an embodiment, the mounting apparatus is configured to raise and lower the search coil relative to the surface.

[0097] In an embodiment, the mounting apparatus comprises a control unit configured to provide an operator of the vehicle with data.

[0098] In an embodiment, the data comprises locations of metal on or under the surface.

[0099] In an embodiment, the locations are provided upon a map.

[0100] According to an aspect of the invention, there is provided a method of detecting metal within the ground using a search coil of a metal detector affixed to a vehicle using a mounting apparatus, the method involving using the mounting apparatus to move the search coil in a first arced path that has an axis of rotation that moves along a second arced path while the vehicle is moving.

[0101] In an embodiment, the arced paths are defined to optimize coverage of the surface area within a path of the vehicle.

[0102] In an embodiment, the search coil is affixed to a mount, wherein the method involves moving the search coil along the first arced path and moving the mount along the second arced path.

[0103] In an embodiment, the first arced path is around the mount, and the second arced path is around the vehicle.

[0104] In an embodiment, either or both of the arced paths comprises full rotation in a circle.

[0105] In an embodiment, the method further involves recording the positions of metal identified by the metal detector.

[0106] In an embodiment, a plurality of search coils are affixed to the mount.

[0107] In an embodiment, the at least one search coil is rotatably affixed to the mount.

[0108] According to an aspect of the invention there is provided a method of detecting metal within the ground using a search coil of a metal detector affixed to a mount, the method involving rotating the search coil along a first arced path having an axis of rotation that moves along a second arced path while the metal detector is moved over the ground.Brief Description of Drawings

[0109] In order to provide a better understanding, embodiments of the present invention will be described, by way of example only, with reference to the accompanying drawings, in which:Figure 1 is a side elevation of a vehicle having a mounting apparatus according to an embodiment of the invention.Figure 2 is a top view of a vehicle having a mounting apparatus according to an embodiment of the invention, with arced paths shown.Figure 3 is a side elevation of a vehicle having a mounting apparatus according to another embodiment of the invention.Figure 4 is a photo of the end of the mounting apparatus comprising the search coils, according to an embodiment of the invention.Figure 5 is a schematic representation of a handle held metal detector according to an embodiment of the invention.Figure 6 is an isometric view of a wearable mounting apparatus according to an embodiment of the present invention.Figure 7 is a side elevation of the apparatus of Figure 6.Figure 8 is a plan view of the apparatus of Figure 6.Figure 9 is an exploded view of the apparatus of Figure 6.Figure 10 is a cross-sectional elevation of the section A-A of Figure 8.Figure 1 1 is an enlargement of the area in B of Figure 10.Figure 12 is an enlargement of the area in C of Figure 10.Figure 13 is an enlargement of the area in D of Figure 10.Description of Embodiments

[0110] Referring to Figures 1 and 2, there is shown a mounting apparatus 10 according to an embodiment of the invention, the mounting apparatus 10 being for a metal detector, and comprising a coupling 20, an extension member 30 extending away from the coupling 20, and a mount 60 attached to a distal end of the extension member 30. The mount 60 is configured to receive at least one search coil 50, 50’ of the metal detector, and wherein the mounting apparatus 10 is configured to move the at least one search coil 50, 50’ along an arced path.

[0111] As shown, the mounting apparatus 10 is suitable to be attached to a vehicle 5, for example using the coupling 20 to attach to a standard tow hitch.

[0112] The coupling 20 may be attached to the front of the vehicle 5.

[0113] It is envisaged that mounting to a vehicle is one application, it is within the scope of the invention for an operator to carry the mounting apparatus 10, for example by wearing a harness that receives the coupling 20, or by simply holding the coupling 20 using it as a handle. An embodiment showing an example using a harness is described below in relation to Figures 6 to 13.

[0114] The arced path may be an arc around the mount 60, or may be an arc around the coupling 20, or may be first and second arcs around the mount 60 and the coupling 20, respectively. The arc(s) may be full rotations in a circle.

[0115] The extension member 30, may be adjustable in length, such as by being telescopic. The extension member 30 may be constructed, either in part or in full, of non-metallic material. In one embodiment, a portion extending from the distal end of the extension member 30 is constructed of non-metallic material. The use of non-metallic material is advantageous in that the material will not interfere, or will reduce interference, with the operation of the search coils 50.

[0116] The mounting apparatus 10 may move the mount 60, and therefore the search coil(s) 50 along an arced path. The mount 60 may be moved by moving the extension member 30 relative to the coupling 20.

[0117] The arced path may extend to either side of the vehicle, for example by up to 30 degrees either side of a centre-line, or further, such as, up to 60 degrees, or 90 degrees. It can be noted that 90 degrees enables the arced path to extend either side of the vehicle by the total length of the extension member 30.

[0118] Alternatively, the arced path may extend a full circle, so the extension member 30 rotates around the coupling 20. In that embodiment, the extension member 30 is arranged to clear the vehicle 5.

[0119] It is envisaged that the preferred embodiment comprises a plurality of search coils 50, 50’ rotating in circles around the mount 60, with the mount being moved along a second path around the coupling 20, with the second path being either a side to side sweep in front of the coupling 20, or a full rotation around the coupling 20.

[0120] The search coils 50, 50’ are ideally mounted so that they, or their plane of rotation, is coplanar with the surface, generally considered to be ground. Predominantly the ground surface is expected to be horizontal, or generally horizontal.

[0121] Some embodiments where two search coils 50, 50’ are used, they may rotate around each other. A plurality of search coils 50, 50’ may orbit one another in a planetary configuration, or they may orbit the mount 60. They may orbit the mount 60 with different radii or rotation, giving different off-sets from the mount 60.

[0122] The mounting apparatus 10 may comprise a control unit 70. It is desirable that the control unit 70 is visible and operable by the operator, and in embodiments in which the mounting apparatus 10 is mounted to the vehicle 5, the control unit 70 may be located inside the vehicle 5, proximal to the driver’s seat.

[0123] The control unit 70 may control parameters of the mounting apparatus 10, for example the speed of movement of the search coil(s) 50, 50’ along the arced path. This may be rotational velocity where the search coil(s) 50, 50’ rotate in full circles.

[0124] The speed of movement and / or extent of movement along the arced path may be determined or adjusted according to the speed of the vehicle 5.

[0125] In embodiments including more than one arced path, the parameters may include the speed of movement along each of these arced paths individually.

[0126] Further parameters that may be adjusted include the height of the mount 60, and therefore the search coils 50, relative to the ground, or surface being searched.

[0127] The height adjustment of the mount 60 may be enabled by an adjustment means at the coupling 20, or the mount 60, or both.

[0128] An aim of the invention may be to optimise coverage of ground searched, and to enable this, the speed of movement along the arced path, or rotational velocity, may be determined based, in part, upon the speed of the vehicle 5. For example, to ensure that one full rotation of a search coil 50 around the mount 60 is completed in the time taken for the vehicle 5 to travel the diameter of a circle described by that rotation. Alternatively, the speed of rotation of a plurality of search coils 50, 50’, may be increased relatively to the speed of the vehicle 5, for example where search coils 50, 50’ have different operating characteristics. As an example, where a first search coil 50 operates at a first frequency intended to search a first size and / or depth, and a second search coil 50’ operates at a second frequency intended to search a second size and / or depth, the speed of rotation of both search coils 50, 50’ may be selected so that both search coils 50,50’ have completed a full rotation in the time taken for the vehicle to travel the diameter of a circle described by that rotation. Doing so advantageously enables the mounting apparatus to complete a full detection of an area at two different depths in the time taken for the vehicle to travel the distance.

[0129] The control unit 70 may be configured to set the parameters based on measured speed of the vehicle 5. The speed may be measured, for example, by use of GPS.

[0130] Alternatively, the control unit 70 may be configured to receive parameters entered by an operator, and to provide the operator with a target speed at which the vehicle 5 should be driven.

[0131] Referring to Figure 3, there is shown a mounting apparatus 10 according to an embodiment of the invention, the mounting apparatus 10 further comprising a first member 40 comprising a first end 44 and a second end 46, wherein the first end 44 is attached to the coupling 20, and wherein the extension member 30 is attached to the second end 46.

[0132] The second end 46 may be higher than the first end 44 so that the extension member 30 extends away from the vehicle 5 at an elevated position.

[0133] The first member 40 may be adjustable in length, such as by being telescopic, so that the height of the second end 46 relative to the vehicle 5 is able to be altered. The first member 40 may further comprise a rotational device, such as a servo motor, to cause the second end 46 to rotate relative to the first 44, thus imparting the movement of the extension member 30 along the arced path.

[0134] The mounting apparatus 10 may further comprise an angular adjustment device 42 configured to impart an angular movement of the extension member 30 with respect to the first member 40, thus enabling height adjustment of the mount 60 relative to the ground.

[0135] In an alternative embodiment, not shown, the extension member 30 comprises a vehicle end that extends beyond the first member 40, and the extension member 30 is pivotally attached to the first member 40 at a pivot point located between the vehicle end and the distal end of the extension member 30.

[0136] In this embodiment, the mounting apparatus 10 may comprise a drive means attached to the vehicle end of the extension member 30, the drive means may be attached to the roof of the vehicle and may impart sideways movement to the vehicle end of the extension member 30, thus causing the distal end of the extension member 30, and the mount 60, to move along the arced path.

[0137] Referring to Figure 4, in addition to the control unit 70, the mounting apparatus 10 may comprise a detector transceiver 80, configured to operate the search coils 50, 50’. The detector transceiver 80 may be analogous to a transceiver of a conventional handheld metal detector, or alternatively may be a transceiver designed to send and receive data to and from one or more search coils 50, 50’ simultaneously.

[0138] The search coils 50, 50’ may be connected in series, with the detector transceiver 80 being configured to interpret the data received from the series connected search coils 50, 50’ and, or instead, may differentiate signals received from each of the search coils 50, 50’.

[0139] The search coils 50, 50’ may be connected in parallel, with the detector transceiver 80 being configured to interpret the data received from the parallel connected search coils 50, 50’ and, or instead, may differentiate signals received from each of the search coils 50, 50’.

[0140] The search coils 50, 50’ may be individually connected to the detector transceiver 80. This may allow discrimination of which search coil 50 or 50’ detected metal.

[0141] The detector transceiver 80 may be configured to provide information from the at least one search coil 50 to an operator of the vehicle 5, such as an audible (tone) and / or visible (light) indication that metal has been detected. The detector transceiver 80 may be located proximal the mount 60 or proximal the operator.

[0142] The detector transceiver 80 may be configured to identify one or more locations (such as by use of GPS) at which the at least one search coil 50, 50’ indicates that metal is present, and to record the one or more locations in a data logger. The recorded locations may be provided on an electronically displayed map of the area covered by the search, and the locations of metal detected by the search coil(s) 50, 50’.

[0143] In embodiments comprising a plurality of search coils 50, 50’, one of the search coils 50 may have different operating characteristics to another of the search coils 50’. For example, a first search coil 50 may operate using pulse induction (PI) and a second search coil 50’ may operate using very low frequency (VLF), for example between 6kHz and 13kHz. Alternatively, search coils 50, 50’ may operate using slightly different frequencies, or using identical operating characteristics. The search coils 50, 50’ may be of different sizes and / or shapes.

[0144] The different operating characteristics enable the search coils 50, 50’ to be optimised to detect different types of metal, or small or large metal objects, or at different depths.

[0145] When operating a plurality of search coils 50, 50’ having the same characteristics and orbit, the search area may be covered more quickly by increasing the speed of the vehicle 5 accordingly.

[0146] In use, the mounting apparatus 10 may be mounted to a vehicle 5 and driven across a surface (such as open ground), wherein the mounting apparatus 10 is configured to sweep the at least one search coil 50, 50’ along a first arced path during movement of the vehicle 5.

[0147] The first arced path may be around a mount 60 at the distal end of the extension member 30, and a plurality of search coils 50, 50’ may be affixed to the mount 60. The coil(s) 50, 50’ may rotate around the mount 60, and the extension member 30 may move the mount 60 along a second arced path, around the coupling 20. The second arced path may be a side to side traverse with respect to the direction of travel of the vehicle 5.

[0148] Either or both of the arced paths may comprise full rotation in a circle, and any or all of the radius and speed of movement along each arced path, and speed of movement of the vehicle 5, may be defined to optimise the coverage of the surface area within the path of the vehicle 5.

[0149] The mount 60 may be raised or lowered according to the terrain and search parameters. For example, with relatively even flat terrain, the operator may position the mount 60 so that the search coils 50, 50’ are close to the ground. Alternatively, where the terrain is rough, having the search coils 50, 50’ too close to the ground may risk damage, such as by contact with a mound in the ground or an obstruction, such as a rock / boulder, so the search coils 50, 50’ may be positioned slightly higher. Similarly travelling up or down hill, or along an incline, may require adjustment.

[0150] Whilst driving, the control unit 70 and / or the detector transceiver 80 may record the locations at which metal objects are detected and indicate these on a map, so that the operator, or another person, may then return with the suitable map locations to dig or uncover the metal objects. The present invention may have particular benefit in gold nugget prospecting.

[0151] Referring to Figure 5, there is shown a hand-held metal detector 100 variation of the invention. Instead of coupling the extension member to a vehicle, the coupling 20 is to a handle 102. In this embodiment there is only one search coil 50, although there may be more than one search coil in the hand-held version. Further in the preferred form of the variation, the search coil is not simply moved in an arc, although it may be, it is preferred to rotate about the mount 60 by way of a motor. In the shown embodiment, the search coil 50 is laterally offset from the motor beneath the mount 60 by an offset member 104. In use this embodiment is carried by the handle 102 and the search coil 50 moves about the mount 60 as the user moves over the ground. Thismeans that the user does not need to swing the search coil 50 back and forth over the ground, instead they may simple walk forward, thus reducing the effort required.

[0152] Referring to Figures 6 to 13, there is shown an alternative mounting apparatus 101 according to an embodiment of the invention. This embodiment extends the embodiment 100 of a hand-held metal detector to being (partly) wearable. The mounting apparatus 101 comprises a coupling 20, an extension member 30 extending away from the coupling 20, and a mount 60 attached to a distal end of the extension member 30. The extension member 30 comprises a beam part 220 and a suspension part 224. The parts 220 and 224 could be viewed as similar, but the other way around, to the members 30 and 40 in the embodiment of Figure 3. The suspension part 224 is preferably non-metallic (such as plastic material). The beam part 220 may be metallic, such as aluminium, but it may also be non-metallic, for example being formed of plastic.

[0153] The mount 60 comprises a connection point to the extension member 30 (at a lower end of the suspension part 224) and has radially extending arms 104. At the ends of the arms are search coils 50, 50’ of the metal detector. The mounting apparatus 10 is configured to move the search coils 50, 50’ along a first arced path, in this case in a circle, with the end of the suspension part 224 coinciding with the axis of rotation. Example rotation of the search coils 50, 50’ is indicated by X.

[0154] The coupling 20 allows the extension member 30 to pivot, such that the mount 60 moves in a second arced path. The movement in the second arced path is preferably in an oscillating manner as indicated by arrows Y. Thus, the movement of the search coils 50, 50’ will be the combination of rotational and pivotal movement X and Y. It is expected that this will permit a greater efficiency of detection over an area in comparison to a standard hand-held metal detector having one search coil equivalent to coil 50 only. Further or alternatively, the search coils 50, 50’ may have different characteristics, as described above, and thus provide greater efficiency in detection accuracy in comparison to using one search coil only.

[0155] In an embodiment, the arms 104 are in opposite directions and are of the same length to permit the search coils to move along a co-orbital path. However, the arms 104 could be of different lengths, providing the coils at different orbital distances from the axis of rotation. The outer limit of the orbits of the coils 50, 50’ may be provided with a ring 230. The ring 230 may serve a protective purpose to prevent movement of the orbital paths of the search coils 50, 50’ from intersecting with an object (e.g. a rock). The ring 230 could also be used to house a third sensor coil having a radius as defined by the outer limit of the orbits of the coils 50, 50’.

[0156] In an embodiment, the mount 60 is suspended by the suspension 224. The suspension part 224 is in turn suspended via a coupling to the beam part 220. Preferably the coupling is inthe form of a hook 240 at or near an end of the beam part 220 distal from the coupling 20, and a loop 241 at the top of the suspension member 224. Alternatively, the coupling may be in the form of a loop at or near an end of the beam part 220 distal from the coupling 20, and a hook, such as a carabiner like hook, at the top of the suspension member 224. This arrangement permits the suspension part 224 to be detachable from the beam part 220.

[0157] In an embodiment, the extension member 30 comprises a motor 226 for rotating the mount 60 and thus the search coils 50, 50’ in the co-orbital path. In an embodiment, the motor 226 connects to the mount 60 by a drive shaft 246. In an embodiment, the motor 226 is in the suspension part 224. In an embodiment the motor 226 is inside a motor housing 242 connected to the coupling 240, 241 which is stationary with respect to the beam part 220. The motor housing 242 may be connected to a shaft housing 247, inside of which the drive shaft 246 is able to rotate. The drive shaft 246 may be mounted within the motor housing 242 by a bearing 248 and within the shaft housing 247 by bearing 262.

[0158] In an embodiment, the beam part 220 connects via the coupling 20 to a wearable item 202. In an embodiment, the coupling permits the beam part 220 to pivot with respect to the wearable item 202. In an embodiment, the coupling comprises a swivel mechanism 222. The swivel mechanism 222 may have a biassing mechanism to centre beam part 220 with respect to the wearable item 202. The wearable item 202 may be in the form of a back harness, that preferably comprises a back support 270. There may be side supports 276 extending from the back support of either side of the belly of the wearer of the item 202. Preferably there are shoulder straps 272 that extend from the back support 270 to the belly supports 276 near or on the belly of the wearer or to a belly strap 274 that preferably extends between the side supports 276 across the belly of the wearer. In an embodiment, the coupling 20 is located substantially around the shoulder blades / neck of the wearer and the beam part 30 is curved over the position of the head of the wearer of the wearable item 202.

[0159] In an embodiment, the extension member 30 comprises a wand member 204 for causing the extension member 30 to pivot with respect to the wearable item 202. In an embodiment, the wand member 202 is pivotably coupled to the support member 224, preferably near the mount 60. In an embodiment, the wand member 204 comprises a handle 208 for the wearer to hold and move to cause the wand member 204 to pivot the extension member 30. In an embodiment, the wand member 204 comprises an arm brace 206 for supporting the arm of the wearer and to minimise stress of the wrist of the wearer. In this embodiment the arm brace 206 when in use extends from the handle 208 at the position of the bottom of the hand of the wearer towards the elbow of the wearer and ends in a cup 210 in which the forearm of the wearer near the elbow can be received.

[0160] By seesaw lever action, pivoting at the handle 208, the weight of the mounting mechanism 101 forward of the centre of gravity will pivot the arm brace 206 so that the cup 210 is urged towards the wearer’s forearm, thus taking weight in the forearm, not in the wrist, and closer to the body of the wearer. Further, when the coupling 20 and the back support 270 are rigid, the weight of the mounting mechanism 101 transferred through the beam part 220 will apply a rotational force downward forward of the wearer’s head. This will urge an upper part of the back support 270 into the wearer’s back and a lower part of the back support 270 away from the wearer’s back, which will be restrained from doing so by the belly strap 274 and the shoulder straps 272.

[0161] The suspension part 224 may be formed of two parts as seen in Figure 11 that are connected by connection 250.

[0162] The motor 244 may be powered by batteries 226 that are housed in the housing 242. The batteries 226 may be removable so as to be replaced, and / or they may be rechargeable.

[0163] The bottom of the shaft housing 247 may be provided with a seal 264 for resisting dust from entering the shaft housing 247 and getting to the bearing 262. The control unit 70 and / or transceiver 80 may be attached to a mounting point 102.

[0164] The skilled reader would readily appreciate the nature of the materials appropriate for making the components of the embodiments of the arrangements described herein. Modifications and variations as would be apparent to the skilled addressee are intended to be covered by the accompanying claims.

[0165] Future patent applications maybe filed in Australia or overseas on the basis of, or claiming priority from, the present application. It is to be understood that the following claims are provided by way of example only and are not intended to limit the scope of what may be claimed in any such future application. Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention or inventions.

Claims

Claims1 . A metal detector comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive at least one search coil, and wherein the mount is configured to rotate the at least one search coil in a respective circular path about an axis of rotation.

2. The metal detector according to claim 1 , wherein the axis of rotation is configured to move in a swing path about the coupling, such that the movement of the least one search coil is a combination of the respective circular path and the swing path.

3. A mounting apparatus for a metal detector, the mounting device comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive at least one search coil of the metal detector, and wherein the mounting apparatus is configured to move the at least one search coil along a combined first arced path and a second arced path.

4. The metal detector according to claim 3, wherein at least one of the at least one search coil is offset from the mount.

5. The metal detector according to claim 3 or 4, wherein the first arced path describes an arc around the mount.

6. The metal detector according to any one of claims 3 to 5, wherein the second arced path describes an arc around the coupling.

7. The metal detector according to any one of claims 3 to 6, wherein the first arced path comprises full rotation in a circle.

8. The metal detector according to any one of claims 3 to 7, wherein the second arced path oscillates through an incomplete rotation.

9. The metal detector according to any one of claims 3 to 8, wherein the axis of rotation of the first arced path moved along the second arced path.

10. The metal detector according to any one of claims 3 to 9, wherein the centre of at least one of the least one search coil is offset from the axis of rotation.1 1 . The metal detector according to any one of claims 3 to 10, wherein the mount is configured to receive two search coils.

12. The metal detector according to any one of claims 3 to 11 , wherein, a first of the search coils comprises different operating characteristics to a second of the search coils.

13. The metal detector according to claim 12, wherein the characteristics include the size of the search coils.

14. The metal detector according to claim 12 or 13, wherein the characteristics include an electrical property of the search coils.

15. The metal detector according to any one of claims 3 to 14, wherein the mounting apparatus comprises a control unit for controlling parameters of the mounting apparatus, wherein the control unit is configured to be mounted proximal to an operator.

16. A mounting apparatus for a handheld metal detector having a search coil, the mounting device comprising; a coupling, an extension member extending away from the coupling, and a mount attached to a distal end of the extension member, wherein the mount is configured to receive the handheld metal detector, and wherein the mounting apparatus is configured to move the handheld metal detector so that the search coil moves along an arced path offset from the mount.

17. The mounting apparatus according to claim 16, wherein the arced path is a circle.

18. The mounting apparatus according to claim 16 or 17, wherein there is a second search coil that moves in a second arced path.

19. A mounting apparatus for mounting a search coil of a metal detector to a vehicle configured to drive across a surface, wherein the mounting apparatus is configured to sweep the search coil along an arced path that combines a first arced movement of a centre of motion of a second arced movement during movement of the vehicle.

20. A method of detecting metal within the ground using a search coil of a metal detector affixed to a vehicle using a mounting apparatus, the method involving using the mounting apparatus to move the search coil along an arced path that has an axis of rotation that moves along a second arced path while the vehicle is moving.

21. A method of detecting metal within the ground using a search coil of a metal detector affixed to a mount, the method involving rotating the search coil along a first arced path having an axis of rotation that moves along a second arced path while the metal detector is moved over the ground.

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