BACKGROUND

The invention relates to a sensor device configured for making an electromagnetic connection with an electric wire comprising a core of electrically conductive material and an outer sheath of electrically insulating material.

Known sensor devices of this type typically comprise a housing that has two sections. A printed circuit board is provided in a first section and the second section is arranged to hold the electric wire. When the two sections are joined together the electric wire is positioned along the printed circuit board. The printed circuit board then senses the changes in the electromagnetic field that is induced by electrical currents through the electric wire.

SUMMARY OF THE INVENTION

A disadvantage of the known sensor devices is that the positioning of the electric wire with respect to the printed circuit board needs to be very accurate. External influences such as inaccurate installation of the sensor device or movement of the installed sensor device may result in small deviations of the position of the wire with respect to the printed circuit board. These deviations may lead to unreliable detection of the electromagnetic field.

It is an object of the present invention to provide a sensor device configured for making an electromagnetic connection with an electric wire comprising a core of electrically conductive material and an outer sheath of electrically insulating material, wherein the sensor device has a more reliable connection with the electric wire.

The invention provides a sensor device configured for making an electromagnetic connection with a first electric wire, wherein the first electric wire comprises a core of electrically conductive material and an outer sheath of electrically insulating material, wherein the sensor device comprises an inlay section for the first electric wire, a confiner that is operable to confine the first electric wire in the inlay section, and a printed circuit board with a first sensor section for sensing an electromagnetic field of the first electric wire, wherein the sensor device is adjustable between an open condition in which the confiner is spaced apart from the inlay section to allow insertion of the first electric wire into the inlay section, and a closed condition in which the confiner confines the first electric wire in the inlay section, wherein in the closed condition the first sensor section is adjacent to the first electric wire, and wherein the printed circuit board is curved at the first sensor section to at least partly surround the first electric wire for sensing the electromagnetic field of the first electric wire.

The sensor according to the invention can be used for making a non-invasive or non-intrusive electromagnetic connectivity with the first electric wire. By providing a printed circuit board that is curved at the first sensor section, the first electric wire is partly surrounded by the sensor section. In this way the sensor section covers a substantial part of the circumferential area of the first electric wire and can therefore receive a sufficient amount of the electromagnetic field that is induced by currents through the first wire regardless of the exact position of the electric wire with respect the sensor section. As a result the connection between the sensor device and the first electric wire will be more reliable. In an embodiment the sensor device comprises a shaft that extends from the inlay section, wherein the confiner is slidable along the shaft for confining the first electric wire in the inlay section. In this way the confiner is conveniently guided towards the inlay section when operated .

In an embodiment thereof the inlay section comprises an arm that extends from the shaft, wherein the distal end of the arm is spaced apart from the shaft, wherein the arm defines a holder between its distal end and the shaft, wherein the first sensor section is positioned in the holder. The sensor device may be easily hooked to the first electric wire by passing the first electric wire between the shaft and the arm into the holder.

In an embodiment thereof the arm is concave towards the confiner, wherein in the closed condition the first electric wire is surrounded by the arm, or by the arm and the shaft over at least 180 degrees. The first electric wire is thereby locked up sideways whereby installation of the sensor device onto the first electric wire is easier.

In an embodiment the printed circuit board at least partly extends around the distal end of the arm.

In an embodiment the sensor device comprises a notch between the shaft and the arm, wherein the notch retains the printed circuit board in the inlay section.

In an embodiment the shaft is a hollow shaft having an internal channel, wherein the printed circuit board extends in at least a part of the internal channel. This arrangement secures the printed circuit board to the sensor device while also protecting it from the environment.

In an embodiment the shaft comprises an outer slide surface and the confiner comprises an inner slide surface, wherein the outer slide surface and the inner slide surface cooperate to align the confiner with respect to the inlay section in a rotational direction around the shaft. In this arrangement the confiner is conveniently guided with the correct orientation towards the inlay section. In an embodiment thereof the external slide surface comprises in the circumferential direction around the shaft an external straight slide surface and an external convex slide surface, wherein the internal slide surface comprises an internal straight slide surface and an internal concave slide surface, wherein the external straight slide surface and the external convex slide surface respectively correspond to the internal straight slide surface and the internal concave slide surface.

In an embodiment the sensor device comprises a tightening knob that is operable to move along the shaft, wherein the tightening knob actuates the confiner to move with the tightening knob along the shaft. The tightening knob allows the confiner to be operated irrespective of the position of the confiner.

In an embodiment thereof the tightening knob is rotatable around the shaft to move the tightening knob along the shaft.

In an embodiment the shaft comprises a threaded surface and the tightening knob comprises an internal thread that cooperates with the threaded surface to move the tightening knob along the shaft when the tightening knob is rotated around the shaft. The threaded interface allows for accurate positioning of the tightening knob and the confiner along the shaft.

In an embodiment the sensor device comprises a cap that at least partly covers the inlay section, wherein the printed circuit board extends at least partly between the inlay section and the cap. The cap keeps the printed circuit board in place and protects it from the environment .

In an embodiment the sensor device comprises an electric communication wire that is electrically connected to the printed circuit board to communicate with an external device .

In an embodiment the electric communication wire is electrically connected to the printed circuit board within the internal channel of the shaft. Thereby the delicate connection between the first electric wire and the printed circuit board is protected from the environment.

In an embodiment the printed circuit board is a flexible printed circuit board. A flexible printed circuit board may be easily mounted onto the sensor device during assembly thereof.

In an embodiment the sensor device is configured for making an electromagnetic connection with the first electric wire and a second electric wire, wherein the second electric wire comprises a core of electrically conductive material and an outer sheath of electrically insulating material, wherein the printed circuit board comprises a second sensor section for sensing an electromagnetic field of the second electric wire, wherein in the closed condition the second sensor section is adjacent to the second electric wire, and wherein the printed circuit board is curved at the second sensor section to at least partly surround the second electric wire for sensing the electromagnetic field of the second electric wire. This sensor device may be connected simultaneously to two electric wires. The electric wires may be part of a twisted pair of electric wires that conduct the same electric signal.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which :

Figure 1 is an isometric view of a sensor device according to an embodiment of the invention;

Figures 2A and 2B are exploded views of the sensor device of figure 1; and Figure 3 shows a flexible printed circuit board of the sensor device in an enlarged view; and

Figures 4A and 4B are longitudinal cuts of the sensor device of figure 1.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a sensor device 1 according to an embodiment of the invention for making a non-intrusive electromagnetic connection with a first electric wire 2 and a second electric wire 3. These electric wires 2, 3 each comprise a stranded core 4 of electrically conductive material, such as copper, and an outer sheath 5 of electrically insulating material, such as a plastic, whereby the electric wires 2, 3 are flexible and easily to configure. The electric wires 2, 3 may form part of a twisted pair electric wires.

The twisted pair electric wire may form part of a bus system of a vehicle, such as a truck, that transmits digital signals between electronic components, wherein the first electric wire 2 and second electric wire 3 conduct electrical signals that need to be monitored by a retrofit monitoring device. This monitoring device may for example monitor the speed of the truck, the position of the gas valves of the engine, or the global position of the truck as provided by the on board navigation system to optimize the performance of the truck and the human driver. The bus system of a vehicle is usually hidden behind the dashboard and behind shields inside the engine department and is therefore hard to electrically branch off. Furthermore it is often legally not allowed to physically interfere with the bus system.

When the first electric wire 2 and second electric wire 3 carry a current a magnetic field is induced around the respective electric wires 2, 3. The sensor device 1 according to the invention is designed to detect changes in the magnetic field around the electric wires 2, 3, to process the changes in the magnetic field into signals and to transmit these signals to the external monitoring device. The sensor device 1 comprises electronics that enable the detection, processing and transmission of the signals. Therefore in the context of this patent an electromagnetic connection combines a non- invasive physical engagement of the electric wires 2, 3 with sensing the electromagnetic fields that are induced by electrical currents through the electric wires 2, 3.

As best shown in figures 2A and 2B the sensor device 1 comprises a plastic base 10 comprising along its center line A an elongate hollow shaft 20 that at one side thereof merges into an inlay section 50 for the electric wires 2, 3. The shaft 20 defines an internal channel 21 that is aligned with the center line A. The shaft 20 has an external slide section 30 and an external tightening section 40. The base 10 holds a flexible printed circuit board (PCB) 70 at the inlay section 50 and inside the internal channel 21. A plastic cap 80 is placed against the inlay section 50 to enclose and protect the printed circuit board 70. A plastic tightening knob 90 and a plastic confiner 100 are arranged around the shaft 20. The printed circuit board 70 is connected to an electric communication wire 6 that is fed through the tightening knob 90 along the center line A to communicate with the external monitoring device.

The external tightening section 40 is located along the shaft 20 at the end thereof opposite to the inlay section 50 and comprises along the circumference of the shaft 20 straight guide surfaces 41 and threaded surfaces 42 between the guide surfaces 41. The guide surfaces 41 and the threaded surfaces 42 are parallel with and extend at opposite sides of the center line A. The external slide section 30 is located along the shaft 20 between the tightening section 40 and the inlay section 50 and has an external slide surface that comprises, along the circumference of the shaft 20, external straight slide surfaces 31 which are a continuation of the straight guide surfaces 41 of the tightening section 40 and external convex slide surfaces 32 between the external straight slide surfaces 31. The threaded surfaces 42 are recessed in radial direction to the center line A with respect to the external convex slide surfaces 32. The internal channel 21 of the shaft 20 comprises a round section 22 which accommodates the electric communication wire 6 and a stepped rectangular section 23 which accommodates the printed circuit board 70 that is described in more detail later on.

The inlay section 50 comprises a central body 51, two arms 52 extending from the central body 51 and two head plates 53 at opposite sides of the central body 51 and arms 52. The central body 51 extends perpendicular to the center line A from the external convex slide surfaces 32 of the shaft 20 and merges along its sides into the arms 52 that are perpendicular to the external straight slide sections 31 of the external slide section 30. The arms 52 extend from the central body 51, wherein a proximal part of the arms 52 tapers away from the central body 51, a subsequent part of the arms 52 pends obliquely away from the shaft 20 and a distal part of the arms 52 pends obliquely back towards the shaft 20, in particular towards the merger of the tightening section 40 and the external slide section 30. The distal part of the arms 52 is spaced apart from the shaft 20. The arms 52 curve around the first and second electric wires 2, 3 for more than 180 degrees with respect to the center line A. The arms 52 define holders for the first and second electric wires 2, 3 in which these are locked up sideways. The electric wires 2, 3 can be brought in front of the holders by a sideward movement transverse to the center line A towards the shaft 20, and can subsequently be moved sideward and parallel to the center line A to be inserted into the holders.

The central body 51 furthermore has at the side facing away from the shaft 20 a rectangular opening 60 which is in line with the rectangular section 23 of the channel 21 of the shaft 20. The shaft 20 transitions smoothly into the central body 51 and subsequently into the arms 52 of the inlay section 50. The arms 52 have a smooth curved outer surface 54 that faces away from the shaft 20 and that transitions at the distal end of the arms 52 into a smooth curved inner surface 55 that faces the shaft 20. Notches 24 are located at the edge between the shaft 20 and the inner surfaces of the arms 52. Round cams 57 protruding parallel to the center line A are positioned on the outer surfaces 54 near each corner of the rectangular section 23 of the channel 21. The central body 51 has at each side of the channel 21 between the outer surfaces 54 of the arms 52 two concave recesses 58 that are separated by a ridge 59. The head plates 53 are positioned along the sides of the central body 51 and the arms 52 and bound the concave recesses 58. The head plates 53 protrude along the outer surfaces 54 and the distal end of the arms 52 creating a raised edge 56. The inner surface 55 transitions smoothly into the head plates 53.

The flexible printed circuit board 70 comprises in this example a one-piece preconfigured strip or film 71 in a shape as described hereafter. The small surface mounted electronic components and circuits on the printed circuit board 70 are not shown for clarity reasons only. The strip 71 comprises a stepped plug section 72 that fits inside the stepped rectangular section 23 of the channel 21 of the shaft 20 and two wider collar sections 73 that cover the surface of the arms 52 tightly. As best shown in figures 4A and 4B the surface of the strip 71 is placed along two opposite inner walls of the rectangular section 23 of the channel 21 and its edges are enclosed between the other two walls. Near the round section 22 of the channel the strip 71 has a semi-cylindrical bend 74 with a wire hole 75 for the electric communication wire 6. At the inlay section 50 of the base 10 the strip 71 widens into outer sections 77 of the collar sections 73. The outer sections 77 curve along the outer surfaces 54 of the arms 52. At the distal ends of the arms 52 the outer sections 77 merge into sensor sections 76 which are positioned in the holder and cylindrically curve along the inner surfaces 55 of the arms 52. The sensor sections 76 abut and partly surround the electric wires 2, 3 for optimal electromagnetic connectivity therewith. The ends of the strip 71 sit inside the notches 24 near the shaft 20. The printed circuit board 70 comprises one or more not shown sensors for sensing the magnetic field that is induced by electrical currents through the stranded cores 4 of the electric wires 2, 3, more particular the sensor sections 76 comprise one or more of such sensors. The sensors are for example inductive sensors or capacitive sensors .

The cap 80 comprises a cap top wall 81 and two cap side walls 82. The cap top wall 81 follows the contours of the outer surface 54 of the arms 52 and covers the opening in the central body 51. The cap top wall 81 extends around the distal ends of the arms 52 whereby it clamps onto the inlay section 50. The cap side walls 82 sit against the head plates 53 of the inlay section 50 and follow the outline thereof for the greater part. Along and parallel to the center of the shaft 20 a first triangular plate 83 extends from the center of the cap side walls 82.

The tightening knob 90 comprises a plastic hood 91 with external gripping grooves 93, a circumferential edge 94 that faces the inlay section 50 and an opening 96 for passage of the electric communication wire 6 that faces away from the inlay section 50. The tightening knob 90 comprises an internal thread 92 that fits around the threaded surfaces 42 of the tightening section 40. The tightening knob 90 comprises along the circumferential edge 94 a snap-connection ring 95.

The tightening knob 90 can be moved with respect to the base 10 in direction B along the center line A by rotating the tightening knob with respect to the base 10 in direction C around the center line A.

The confiner 100 surrounds the shaft 20 of the base 10 and has a generally rectangular shaped cross section when looking in the direction of the center line A. The confiner 100 comprises two confiner side walls 102 that correspond to and are parallel to the cap side walls 82 of the cap 80. In this example the confiner side walls 102 are positioned further away from the center line A than the cap side walls 82 to allow the respective side walls 82, 102 to move along each other. The confiner side walls 102 are confined by the cap side walls 82. The confiner side walls 102 are connected and spaced apart by two first connecting bodies 105 which are orientated perpendicular to the confiner side walls 102 at opposite sides of the center line A. The first connecting bodies 105 are connected and spaces apart by two second connecting bodies 115 which are orientated parallel to the confiner side walls 102 at opposite sides of the center line A. The first 105 and second 115 connecting bodies together define a passage for the shaft 20 of the base 10. A spherical cover section 120 extends between the confiner side walls 102 and covers the first 105 and second 115 connecting bodies.

The confiner 100 is arranged to slide along the shaft 20 of the base 10 and therefore has an internal slide surface that comprises, in the circumferential direction around the shaft 20, internal straight slide surfaces 101 on the first connecting bodies 105 and internal concave slide surfaces 108 on the second connecting bodies 115. The internal straight slide surfaces 101 and the internal concave slide surfaces 108 are respectively in sliding contact with the external straight slide surfaces 31 and the external convex slide surfaces 32 of the external slide section 30 and respectively with the straight guide surfaces 41 and threaded surfaces 42 of the external tightening section 40. This configuration allows the confiner 100 to slide along the center line A but prevents that it rotates with respect thereto. The confiner 100 is indexed with respect to the center line A.

The confiner side walls 102 have a second triangular plate 103 that extends from the center thereof towards the corresponding first triangular plate 83. The confiner side walls 102 furthermore comprises two protrusions 104 near the corners thereof that are oriented towards the cap side wall 82 sections that cover the arms 53 of the inlay section 50.

A first side 106 of the first connecting bodies 105 is flush with the respective confiner side walls 102 between the protrusions 104 and the second triangular plate 103 thereof. The first side 106 has a trough 110 that extends between the respective confiner side walls 102. The first side 106 of the first connecting bodies 105 transitions smoothly into the internal straight slide surface 108 and into a second side 107 that is orientated parallel to the center line A. The second side 107 faces away from the center line A and is recessed with respect to the edges of the confiner side walls 102. Near the cover section 120 the second side curves away from the center line A and transitions into the cover section 120.

The cover section 120 comprises a ring shaped recess 121 that corresponds to the snap-connection ring 95 of the tightening knob 90. Two cams 122 that protrude towards the center line A are positioned in the recess 121 centrally between the confiner side walls 102. The cams 122 engage with the snap-connection ring 95 when it is inserted into the recess 121. The configuration of the snap-connection ring 95 and the cams 122 makes that the tightening knob 90 is fixated with respect to the confiner 100 in directions parallel and perpendicular to the center line A while it allows for rotation of the tightening knob 90 with respect to the confiner 100 around the center line A. When the tightening knob 90 is moved along the base 10, the confiner 100 moves along the base 10 with it in direction B.

As best shown in figure 1 the sensor device 1 is in an open condition with the confiner 100 spaced apart from the inlay section 50 of the base 10. The sensor device 1 may be connected to the first 2 and second 3 electric wires by inserting the electric wires 2, 3 into the inlay section 50 between the arms 52 and the shaft 20 of the base 10. The electric wires 2, 3 are orientated along and parallel to the sensor sections 76 of the printed circuit board 70 for optimal electromagnetic connectivity therewith.

The sensor device 1 can be brought from the open condition to a closed condition by rotating the tightening knob 90 and therewith moving the tightening knob 90 and the confiner 100 in direction B along the shaft 20 towards the inlay section 50. In the closed condition the electric wires 2, 3 are confined by the inlay section 50 and the confiner

100. The electric wires 2, 3 are held in place against the sensor sections 76 of the printed circuit board 70 by the troughs 110 of the confiner 100.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.