Position encoder using saturable reactor interacting with magnetic fields varying with time and with position

An apparatus for generating a signal indicative of the relative position of first and second relatively movable members in a measurement direction, comprising:

• means carried by one of said members, for generating a magnetic field whose strength alternates in sense with position in the measurement direction;
• a saturable magnetic element located, in use, within said positionally varying magnetic field;
• drive means for generating a magnetic field which varies with time and which, in use, interacts with said positionally varying magnetic field to cause at least one portion but not all of the element to saturate and/or unsaturate with variation of the time varying magnetic field;
• and
• at least one sense conductor carried on the other one of said members for sensing a magnetic field generated by said at least one portion as it is driven into and/or out of saturation with the time varying magnetic field and for outputting a signal which varies in dependence upon the sensed magnetic field and upon the relative position of said sense conductor and said at least one portion;
• wherein the arrangement is such that relative movement of said first and second members causes a relative movement between said at least one portion and said at least one sense conductor, whereby said signal output by said sense conductor varies in dependence upon the relative position of said first and second members.

An apparatus for generating a signal indicative of the relative position of first and second relatively movable members, comprising:

• means carried by one of said members, for generating a magnetic field whose strength varies with position in the measurement direction;
• a saturatable magnetic element located, in use, within said positionally varying magnetic field;
• drive means for generating a magnetic field which varies with time and which, in use, interacts with said positionally varying magnetic field to cause at least one portion but not all of the element to saturate and/or unsaturate with variation of the time varying magnetic field;
• and
• at least one sense conductor carried on the other one of said members for sensing a magnetic field generated by said at least one portion as it is driven into and/or out of saturation with the time varying magnetic field and for outputting a signal which varies in dependence upon the sensed magnetic field and upon the relative position of said sense conductor and said at least one portion;
• wherein the arrangement is such that relative movement of said first and second members causes a relative movement between said at least one portion and said at least one sense conductor, whereby said signal output by said sense conductor varies in dependence upon the relative position of said first and second members.

An apparatus for generating a signal indicative of the relative position of first and second relatively movable members in a measurement direction, the apparatus comprising:

• a first magnetic field generator, carried by one of said members, for generating a magnetic field whose strength varies with position in the measurement direction;
• a saturable magnetic element located, in use, within said positionally varying magnetic field;
• a second magnetic field generator for generating a magnetic field which varies with time and which, in use, interacts with said positionally varying magnetic field to cause at least one portion but not all of the element to saturate and/or unsaturate with the variation of the time varying magnetic field;
• and
• at least one sense conductor carried on the other one of said members for sensing a magnetic field generated by said at least one portion as it is driven into and/or out of saturation with the time varying magnetic field and for outputting a signal which varies in dependence upon the sensed magnetic field and upon the relative position of said sense conductor and said at least one portion;
• and
• wherein the arrangement is such that relative movement of said first and second members causes a relative movement between said at least one portion and said at least one sense conductor, whereby said signal output by said sense conductor varies in dependence upon the relative position of said first and second members.

An apparatus for generating a signal indicative of the relative position of first and second relatively movable members in a measurement direction, the apparatus comprising:

• a first magnetic field generator, carried by one of said members, for generating a magnetic field whose strength varies in an alternating fashion with position in said measurement direction;
• a saturable magnetic element located, in use, within said positionally varying magnetic field;
• a second magnetic field generator for generating a magnetic field which varies with time and which, in use, interacts with said positionally varying magnetic field to cause at least one portion but not all of the element to saturate and/or unsaturate with the variation of the time varying magnetic field;
• and
• at least one sense conductor carried on the other one of said members for sensing a magnetic field generated by said at least one portion as it is driven into and/or out of saturation and for outputting a signal which varies in dependence upon the sensed magnetic field and upon the relative position of said sense conductor and said at least one portion;
• and
• wherein the arrangement is such that relative movement of said first and second members causes a relative movement between said at least one portion and said at least one sense conductor, whereby said signal output by said sense conductor varies in dependence upon the relative position of said first and second members.