Electromagnetic communication interface

• US 4,983,963 A
• Filed: 05/31/1989
• Issued: 01/08/1991
• Est. Priority Date: 03/01/1989
• Status: Expired due to Fees

• Current Assignee: Raytel Group Ltd.
• Original Assignee: Raytel Group Ltd.
• Inventors: Hodgetts, John L., Hodson, Martin J.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Lau, Yuk H.
• Application Number:
  US07/359,401
• Time in Patent Office: 587 Days
• Field of Search: 340/870.31, 340/825.54, 340/687, 340/545, 340/547, 340/551, 340/870.32, 340/825.69, 340/825.72, 49/280, 49/139, 49/213, 49/360
• US Class Current: 340/5.61
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils

Abstract

An electromagnetic communication interface including two units each of which contains a coil and associated circuit means. One of the units also includes a core positioned within the coil of that unit and having a free end which may be inserted into the coil of the other unit. When this is done, a magnetic flux link is provided between the two coils and the two circuit means may communicate with one another. The first unit may be mounted on a vehicle body and the second unit on a sliding door of the vehicle. It may be arranged for the magnetic flux link to be formed when the door is closed. A "door-open" signal, generated, for example, by a passenger pressing a push button on the door, may be transmitted via the magnetic flux link to a door opening mechanism mounted on the vehicle body.

Claims

1. An electromagnetic communication interface comprising:

a first unit including a first coil and first circuit means for modulating the magnetic flux produced by the first coil and for responding to modulations of the magnetic flux cutting the first coil, the first circuit means including power input means connectable to an external power source and arranged to modulate the magnetic flux produced by the first coil into groups of first pulses;

and a second unit movable relatively to the first unit and including a second coil and second circuit means for modulating the magnetic flux produced by the second coil and for responding to modulations of the magnetic flux cutting the second coil;

the second circuit means including energy storage means for storing the energy derived from the magnetic flux produced by the first coil of the first unit;

wherein one of the first and second units also includes a core positioned within the coil of the said one unit and having a free end projecting out of said coil, whereby, when the free end of the core is inserted into the coil of the other of the first and second units, the magnetic flux produced by the first coil cuts the second coil and the magnetic flux produced by the second coil cuts the first coil;

wherein the second circuit means includes input signal input means and is arranged, in response to the input signal input means receiving an input signal and upon detecting a gap between the groups of first pulses of the magnetic flux produced by the first coil cutting the second coil, to use energy stored in the energy storage means to modulate the magnetic flux produced by the second coil into a second pulse; and

wherein the first circuit means includes output signal output means and is arranged, upon detecting the second pulse of the magnetic flux produced by the second coil cutting the first coil, to output an output signal from the output signal output means.

2. An electromagnetic communication interface according to claim 1, wherein the second unit is arranged to be powered only by energy derived from the magnetic flux produced by the first coil of the first unit.

3. A vehicle comprising:

a vehicle body;

a door movably mounted on the vehicle body so as to be movable from a first position to a second position;

an electromagnetic communication interface comprising;

a first unit including a first coil and first circuit means for modulating the magnetic flux produced by the first coil and for responding to modulations of the magnetic flux cutting the first coil, the first circuit means including power input means connectable to an external power source and arranged to modulate the magnetic flux produced by the first coil into groups of first pulses;

and a second unit movable relatively to the first unit and including a second coil and second circuit means for modulating the magnetic flux produced by the second coil and for responding to modulations of the magnetic flux cutting the second coil;

the second circuit means including energy storage means for storing the energy derived from the magnetic flux produced by the first coil of the first unit;

wherein one of the first and second units also includes a core positioned within the coil of the said one unit and having a free end projecting out of said coil, whereby, when the free end of the core is inserted into the coil of the other of the first and second units, the magnetic flux produced by the first coil cuts the second coil and the magnetic flux produced by the second coil cuts the first coil;

wherein the second circuit means includes input signal input means and is arranged, in response to the input signal input means receiving an input signal and upon detecting a gap between the groups of first pulses of the magnetic flux produced by the first coil cutting the second coil, to use energy stored in the energy storage means to modulate the magnetic flux produced by the second coil into a second pulse; and

wherein the first circuit means includes output signal output means and is arranged, upon detecting the second pulse of the magnetic flux produced by the second coil cutting the first coil, to output an output signal from the output signal output means;

the first unit being mounted on the vehicle body, the second unit being mounted on a door of the vehicle and the first unit and the second unit being arranged so that, when the door is at its first position, a free end of the core is inserted into the coil of said other of the first unit and the second unit;

input signal generating means mounted on the door for generating an input signal in response to actuation by a user and for supplying the input signal to the input signal input means of said second unit; and

door movement means mounted on the vehicle body and responsive to the output signal output by the output signal output means of the first unit to move the door from its first position to its second position.