AU2006288018B2

AU2006288018B2 - Hidden fitting locator

Info

Publication number: AU2006288018B2
Application number: AU2006288018A
Authority: AU
Inventors: Peter Alan Royle
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-09-11
Filing date: 2006-09-06
Publication date: 2010-04-01
Anticipated expiration: 2026-09-06
Also published as: WO2007030024A2; WO2007030024A3; AU2006288018A1

Description

WO 2007/030024 PCT/NZ2006/000235 TITLE: HIDDEN FITTING LOCATOR FIELD OF THE INVENTION 5 The present invention relates to the field of devices for locating hidden fittings or fixings behind or inside walls, more specifically devices for locating electrical fittings behind wall lining materials. BACKGROUND 10 Fittings, especially electrical fittings, consist of two parts:- an internal fitting which is fixed to the framework of a wall, prior to applying the wall lining material, and a surface component, fixed over the internal fitting after the wall lining material is applied and smoothed. 15 The time between fixing the internal fitting to the framework and the wall lining being ready for the surface component to be installed can be days, or even weeks. With this length of time between steps, the contractor installing the internal fittings can work on a number of different jobs and, even with extensive notes, the exact location of the 20 internal fittings is often forgotten. This means that the contractor must employ some method to locate the internal fittings. Devices that locate elements of the framework (so called "stud finders") are not sensitive enough, so the wall often is mechanically probed to locate the internal fittings. This mechanical probing takes time and can lead to unsightly holes that need to be repaired prior to finishing the wall; both the probing 25 and the repair add to the cost of the job. In some cases, the damage to the wall lining material may not be easily or cheaply repaired, and this can lead to expensive remedial work being necessary. A further problem can 'arise if different sized internal fittings are used and the 30 orientation and/or location of these fittings is uncertain. The device and method of locating the internal fitting must be reliable and low cost to ensure widespread use over the presently used methods. 35 Various devices have been developed to detect the hidden wall fittings, some detecting the presence of magnets or iron based materials present in the fittings. 1 WO 2007/030024 PCT/NZ2006/000235 These devices suffer interference from the Earth's magnetic field and other extraneous electromagnetic / magnetic forces which can reduce their precision and therefore usefulness. 5 OBJECT OF THE INVENTION It is therefore an object of the present invention to provide a hidden fitting locator that incorporates means of reducing or eliminating the effect of the Earth's magnetic field, or other extraneous magnetic or electromagnetic fields, to improve the precision with i which a hidden fitting can be detected. It is also an object of the present invention to provide one or more of the following: 1. A low cost, reliable, non-destructive device that allows the fast -and reliable location of fittings behind a wall lining materials without 15 damaging the lining material, thus overcoming the shortcomings of the presently used methods. 2. A device that can determine the orientation of a hidden fitting without mechanical probing of the wall. 3. A device that provides the consumer with a useful choice. 20 DISCLOSURE OF THE INVENTION The present invention provides a locator configured to locate a fitting which includes one or more magnetic sources, said locator includes one or more magnetic field 25 sensors and a circuit configured to take a calibrate reading, such that the locator is configured to use the calibrate reading to reduce the effect of background magnetic and electromagnetic fields when locating the fitting. Preferably the calibrate reading is taken before the locator is used to locate the fitting. 30 Preferably the locator includes four magnetic field sensors that lie on the same plane. In a highly preferred form the magnetic field sensors are laid out in a T shape. In a further preferred form the magnetic field sensors lie on a plane that is parallel to the wall when the locator is in use. In a preferred embodiment there is more than one 35 magnetic field sensor laid out in a three dimensional pattern. 2 WO 2007/030024 PCT/NZ2006/000235 Preferably the locator includes one or more visual display devices configured to visually indicate the location of the fitting. In a highly preferred form the visual display devices are indicator lights. In a still more preferred form there are four first indicator lights that indicate the direction in which the locator should be moved, and a second 5 indicator light that illuminates when the locator is aligned with the fitting. In a preferred form the visual display unit is an LCD (liquid Crystal Display) device. Preferably the locator includes a calibrate switch and memory such that the calibrate switch is configured to take the calibrate reading from the or each magnetic field 10 sensor and store this in the memory. Preferably the locator includes a locate switch that is activated to locate the fitting. Preferably the locator includes an audio output device. In a highly preferred form the 15 audio output device varies the frequency/volume of its output depending on the distance from the fitting. It is further preferred that the locator includes a case that provides a base which includes two or more marking means configured to mark the surface in such a way as 20 to indicate the location of the hidden fitting; the base further includes one or more non marking resilient pads configured to prevent damage to the surface. The marking means are selected from the list that includes such things as metal pins, chalk, graphite, non-staining ink pads or the like; said marking means may be resiliently mounted. 25 Preferably the locator is dimensioned such that when the fitting is located the locator base can be drawn around to mark the location of the fitting on the surface of the wall. Preferably the locator incorporates a level and/or illumination device configured to 30 allow the locator to be levelled or illuminated respectively. Preferably the locator is made of a non conducting and non magnetic material, such as a polymer. 35 The method for calibrating the locator includes the following steps: 3 WO 2007/030024 PCT/NZ2006/000235 A. the calibrate switch is activated; B. a calibrate reading is taken; C. the calibrate reading is stored in memory. 5 Preferably the method for using the locator includes the following steps: D. the locate switch is activated; E. a first locate reading is taken from each sensor; F. the first locate reading and the stored calibrate reading are combined to 10 give a first indication reading; G. the first indication readings from each sensor are combined by the processing section to generate a first visual indication; H. the locator is moved based on the first visual indication; I. a new locate reading is taken; 15 J. the new locate reading and stored calibrate reading are combined to generate a new indication reading; K. the new indication readings from each sensor are combined in the processing section to generate a new visual indication; L. does the new visual indication show where the hidden fitting is located? 20 If not go to step M, if so go to step N; M. the locator is moved based on the new visual indication and then step I to L are repeated; N. the location of the hidden fitting is marked. 25 In a preferred embodiment the method of using the locator includes steps A to C, such that step A is preceded by step D, so that the method includes the following steps in order: D. the locate switch is activated; 30 A. the calibrate switch is activated; B. a calibrate reading is taken; C. the calibrate reading is stored in memory. Preferably following step C, the calibrate switch is deactivated before proceeding with 35 later steps. 4 WO 2007/030024 PCT/NZ2006/000235 Preferably in this embodiment the locate switch is an on/off switch. It is further preferred that this locate switch is a latching on/off switch. Preferably in this embodiment step C is followed by steps E to N to locate the fitting, 5 such that the method includes the following steps in order: D. the locate switch is activated; A. the calibrate switch is activated; B. a calibrate reading is taken; 10 C. the calibrate reading is stored in memory; E. a first locate reading is taken from each sensor; F. the first locate reading and the stored calibrate reading are combined to give a first indication reading; G. the first indication readings from each sensor are combined by the 15 processing section to generate a first visual indication; H. the locator is moved based on the first visual indication; 1. a new locate reading is taken; J. the new locate reading and stored calibrate reading are combined to generate a new indication reading; 20 K. the new indication readings from each sensor are combined in the processing section to generate a new visual indication; L. does the new visual indication show where the hidden fitting is located? If not go to step M, if so go to step N; M. the locator is moved based on the new visual indication and then step I 25 to L are repeated; N. the location of the hidden fitting is marked. Preferably in this embodiment the calibrate switch is deactivated before step E is commenced. 30 DESCRIPTION OF DRAWINGS By way of example only a specific embodiment of the present invention is described in detail with reference to the accompanying drawings, in which: 35 5 WO 2007/030024 PCT/NZ2006/000235 Fig. 1 shows a side view of the locator and a cross sectional view of a wall and hidden fitting, with the locator on the surface of the wall. Fig. 2 shows an elevation view of the hidden fitting and wall. 5 Fig. 3 is a plan view of the locator; Fig. 4 is a side elevation of the locator; 10 Fig. 5 is a plan view of the sensor layout; Fig. 5a is a block diagram of the locator. Fig. 6 is a flowchart of the calibration process for the locator; 15 Fig. 7 is a flowchart of the process for finding a hidden fitting using the locator after the calibration process is completed. BEST MODE FOR CARRYING OUT THE INVENTION 20 Referring to Figs. 1 to 4a hidden fitting locator (1) is shown. The locator (1) is configured to locate a fitting (25) of standard type which is fixed to a framework (not shown) behind a finished wall (26). Said fitting (25) includes two magnetic locator pins (27, 28), one magnetic locator pin (27,28) being retained in each of two fixing points 25 (29,30) respectively. The locator (1) includes a rigid case (40) with an ellipsoidal handle (41) and a locator base (42). The locator base (42) is a rectangular box (44) with a foot support (45) mounted on each corner. Each said foot support (45) includes a foot (46) configured so to contact the wall when the locator (1) is in use. Each said foot (46) is made of a non marking material and dimensioned to maintain the locator (1) parallel to, and spaced apart from, the surface of the wall (26) when in use. The ellipsoidal handle (41) includes four triangular first indicator lights (50, 51, 52, 53), 35 arranged in a cross, and one rectangular second indicator light (54). Each indicator light (50, 51, 52, 53, 54) is located on an exposed surface (55) of the ellipsoidal handle 6 WO 2007/030024 PCT/NZ2006/000235 (41) which in use is closest to the person using the locator (1). Each first indicator light (50, 51, 52, 53) is a triangular shape so that it acts as an arrowhead when illuminated and thereby indicates the direction the locator (1) should be moved to approach the fitting (25). When the locator (1) is directly over, and aligned with, the fitting (25) to be 5 found, the second indicator light (54) is illuminated. The outline of the fitting (25) can now be drawn on the wall by drawing around the locator base (42) portions between the foot supports (45) which is dimensioned to allow this. Alternatively the locator (1) can be pressed towards the wall which causes a marking 10 point (not shown) in each foot (46) to indent or otherwise mark the wall. By joining the indents or marks the outline of the fitting (25) is revealed. The locator base (42) houses a circuit board (60) which is shown in Fig. 5. The circuit board (60) includes 4 field sensors (61) configured to detect a magnetic field. 15 Preferably these field sensors (61) are magneto-resistive cells. The field sensors (61) are laid out in a T shaped pattern with two field sensors (61) parallel to one side of the circuit board and the remaining two parallel to an adjacent side. This pattern of field sensors (61) has been found to allow the locator (1) to find the magnetic pins (27,28) in the fitting (25) with high precision. The circuit board (60) is mounted such that all of 20 the field sensors (61) lie on a plane which, when the locator (1) is in use, is parallel to the surface of the wall. The layout of the field sensors (61) has also been found to allow the effective elimination of most background magnetic fields such as the Earth's magnetic field. 25 However it should be noted that local magnetic and electromagnetic fields may still interfere to some extent. With reference to Fig. 5a the locator (1) includes a calibrate switch (70), a locate switch (71), a reading section (72), memory (73) and a processing section (74). The 30 calibrate switch (70), when activated, causes the locator (1) to action the steps shown in Fig. (6) and described in detail below. The locate switch (71), when activated, causes the locator (1) to action the steps shown in Fig. (7) and as detailed below. The reading section (72), when activated by either of the switches (71, 72), is configured to take a reading from each field sensor (61) then forward this to the processing section 35 (74) and/or store the reading taken in the memory (73) for later use. The processing 7 WO 2007/030024 PCT/NZ2006/000235 section (74) is configured to process the readings received and activate the required indicator lights (50, 51, 2, 53, 54) so that the hidden fitting can be located. The calibration process, which must be carried out with the locator (1) at least 1m 5 away from the fitting (25), includes the following steps: A. the calibrate switch (70) is activated; B. a calibrate reading (80) is taken; C. the calibrate reading (80) is stored in memory (73). 10 With the locator at least 1m from the fitting (25) the calibration process is initiated. During this process a reading from each of the field sensors (61) is taken, this is a calibrate reading (80) and is representative of the background electromagnetic and magnetic field around the locator (1). The calibrate reading (80) taken is then stored in 15 the memory (73) and acts as an "artificial zero" for the locator (1), much like the tare weight on a set of scales. This calibrate reading (80) is removed from each of the field sensor (61) readings when the locator (1) is being used to find the fitting (25), this has been found to improve the precision with which a fitting (25) can be located. 20 Once the calibrate reading (80) is taken then, with the calibrate switch (70) in an inactive state, the following steps are undertaken to locate the fitting (25): D. the locate switch (71) is activated; E. a first locate reading (81) is taken from each sensor (61); 25 F. the first locate reading (81) and the stored calibrate reading (80) are combined to give a first indication reading (82); G. the first indication readings (82) from each sensor are combined by the processing section (74) to generate a first visual indication (84); H. the locator (1) is moved based on the first visual indication (84); 30 1. a new locate reading (85) is taken; J. the new locate readings (85) and stored calibrate reading (80) are combined to generate a new indication reading (86); K. the new indication readings (86) from each sensor are combined in the processing section (74) to generate a new visual indication (88) 35 L. does the new visual indication (88) show where the hidden fitting is located? 8 WO 2007/030024 PCT/NZ2006/000235 If not go to step M, if s.o go to step N; M. the locator (1) is moved based on the new visual indication (88) and then step I to L are repeated; N. the location of the fitting (25) is marked. 5 In step F or step J the calibrate reading (80) is simply subtracted from the locate reading (81,85), though it is envisaged that a more complex relationship may be needed in some circumstances. 10 In steps G and K the visual indication (84, 88) is displayed by illuminating a pattern of indicator lights (50, 51, 52, 53, 54) so that they indicate the direction to move the locator (1). The locate switch (71) can be a latching or non-latching switch of known type, and the 15 calibrate switch (70) is a push button switch of known type. It should be clear to those skilled in the art that the orientation of the locator (1) for the calibration and location steps must be essentially the same. 20 In a further embodiment the locate switch (71) is an on/off switch of known type. When the locate switch (71) is first activated the locator (1) is positioned more than 1m from the expected location of the fitting (25) and steps A to C in Fig. 6 are undertaken. The calibrate switch (70) is then deactivated and steps E to N, from Fig. 7, are undertaken to locate the fitting (25). 25 In a further embodiment (not shown) the sensors (61), reading section (72), memory (73) and processing section (74) are all integrated into a single integrated circuit. In a still further embodiment the indicator lights (50, 51, 52, 53, 54) are incorporated 30 into a single integrated package, which may be an LCD (Liquid Crystal Display) or similar device. In a further embodiment (not shown) the locator (1) includes an audio output to indicate the direction to move the locator, such as a tone whose frequency or volume 35 is changed depending on the distance to the fitting (25). 9 WO 2007/030024 PCT/NZ2006/000235 In a further embodiment the field sensors (61) are laid out in three dimensions. It should be noted that although the term "wall" is used it is understood that the fitting may be hidden from view in pillars, floors, ceilings or similar and still be located by the 5 locator. In addition the locator could be used to locate magnetic sources obscured from view where these magnetic sources are not associated with a fitting. For example cables, plastic pipes, wooden beams, plastic structures or similar may have magnetic sources embedded that the locator can be used to locate. 10

Claims

1. A locator configured to locate the position and orientation of a hidden fitting, which includes two or more magnetic sources, wherein said locator includes 5 two or more magnetic field sensors and a circuit configured to take a calibrate reading, such that the locator is configured to use the calibrate reading to reduce the effect of background magnetic and electromagnetic fields when locating the fitting. 10

2. The locator as claimed in claim 1, characterised in that there are at least three magnetic field sensors.

3. The locator as claimed in claim 1, characterised in that there are four magnetic field sensors that lie on the same plane. 15 3. The locator as claimed in claim 2, characterised in that the magnetic field sensors are laid out in a T shape.

4. The locator as claimed in claim 1, characterised in that the magnetic field 20 sensors lie on a plane that is parallel to the wall when the locator is in use.

5. The locator as claimed in claim 1, characterised in that the locator includes one or more visual display devices configured to visually indicate the location of the fitting. 25

6. The locator as claimed in claim 5, characterised in that the visual display devices are indicator lights.

7. The locator as claimed in claim 6, characterised in that there are four first 30 indicator lights that indicate the direction in which the locator should be moved, and a second indicator light that illuminates when the locator is aligned with the fitting.

8. The locator as claimed in claim 5, characterised in that the visual display unit is 35 an LCD (Liquid Crystal Display) device. 11

9. The locator as claimed in any one of claims 1 to 8, characterised in that the locator includes an audio output device. 5

10. The locator as claimed in claim 9, characterised in that the audio output device varies the frequency/volume of its output depending on the distance from the fitting.

11. The locator as claimed in claim 1, characterised in that the locator includes a 10 case that provides a base which includes two or more marking means configured to mark a surface in such a way as to indicate the location of the fitting; the base further includes one or more non marking resilient pads configured to prevent damage to the surface. 15

12. The locator as claimed in claim 11, characterised in that the marking means are selected from the group consisting of metal pins, chalk, graphite, non staining ink and pads.

13. The locator as claimed in claim 12, characterised in that the marking means 20 are resiliently mounted.

14. The locator as claimed in any one of claims 11 to 13, characterised in that the locator is dimensioned such that when the fitting is located the base can be drawn around to mark the location of the fitting on the surface of the wall. 25

15. The locator as claimed in any one of claims 1 to 14, characterised in that the locator incorporates a level and/or illumination device configured to allow the locator to be levelled or illuminated respectively. 30

16. The locator as claimed in claim 1, characterised in that the locator is made of a non conducting and non magnetic material.

17. The locator as claimed in any one of claims 1 to 16, characterised in that the locator includes a calibrate switch and memory such that the calibrate switch 12 enables the calibrate reading to be taken from the or each magnetic field sensor and store this in the memory.

18. A method for calibrating the locator as claimed in claim 17, characterised in 5 that it includes the following steps: A. the calibrate switch is activated; B. a calibrate reading is taken; C. the calibrate reading is stored in memory. 10

19. The method as claimed in claim 18, characterised in that the method includes the following steps: D. the locate switch is activated; 15 E. a first locate reading is taken from each sensor; F. the first locate reading and the stored calibrate reading are combined to give a first indication reading; G. the first indication readings from each sensor are combined by the processing section to generate a first visual indication; 20 H. the locator is moved based on the first visual indication; 1. a new locate reading is taken; J. the new locate reading and stored calibrate reading are combined to generate a new indication reading; K. the new indication readings from each sensor are combined in the 25 processing section to generate a new visual indication; L. does the new visual indication show where the hidden fitting is located? If not go to step M, if so go to step N; M. the locator is moved based on the new visual indication and then step I to L are repeated; 30 N. the location of the hidden fitting is marked.

20. The method as claimed in claim 18, characterised in that step A is preceded by step D, so that the method includes the following steps in order: 35 D. the locate switch is activated; 13 A. the calibrate switch is activated; B. a calibrate reading is taken; C. the calibrate reading is stored in memory. 5

21. A method for calibrating the locator as claimed in claim 17, characterised in that it includes the following steps in order: D. the locate switch is activated; A. the calibrate switch is activated; 10 B. a calibrate reading is taken; C. the calibrate reading is stored in memory; E. a first locate reading is taken from each sensor; F. the first locate reading and the stored calibrate reading are combined to give a first indication reading; 15 G. the first indication readings from each sensor are combined by the processing section to generate a first visual indication; H. the locator is moved based on the first visual indication; 1. a new locate reading is taken; J. the new locate reading and stored calibrate reading are combined to 20 generate a new indication reading; K. the new indication readings from each sensor are combined in the processing section to generate a new visual indication; L. does the new visual indication show where the hidden fitting is located? If not go to step M, if so go to step N; 25 M. the locator is moved based on the new visual indication and then step I to L are repeated; N. the location of the hidden fitting is marked. 30 14