Rolamite sensor

An apparatus comprising:

• a movable member at least in part of ferromagnetic material;
• a base mounted on a chassis and having a guide surface defining a path along which said movable member moves, said movable member being movable along said guide surface from a first position due to a force acting thereon;
• a band of flexible, electrically conductive material which at least partially encircles said movable member and which is partially displaced upon movement of said movable member, said band having first and second end portions;
• means for fixedly attaching said first and second end portions of said band to said base;
• an electrically conductive member at a location spaced from said movable member when said movable member is in said first position and in the path of displacement of said band, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• and
• an electromagnet selectively operable to move said movable member along said guide surface from said first position to said second position to complete said circuit to test the apparatus, said electromagnet including a non-ferromagnetic frame and a U-shaped core attached to said frame, said conductive member being located between said coil and said movable member when said movable member is in its first position, said chassis having a portion on which said frame is selectively fixed.

An apparatus comprising:

• a movable member made at least in part of ferromagnetic material;
• a base having a guide surface defining a path along which said movable member moves, said movable member being movable along said guide surface from a first position due to a force acting thereon;
• a band of flexible, electrically conductive material which at least partially encircles said movable member and which is partially displaced upon movement of said movable member, said band having first and second end portions;
• means for fixedly attaching said first and second end portions of said band to said base;
• an electrically conductive member at a location spaced from said movable member when said movable member is in said first position and in the path of displacement of said band, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• and
• an electromagnet selectively operable to move said movable member along said guide surface from said first position to said second position to test the apparatus, said electromagnet including a one-piece core and a coil wound directly on said core, said core including a central portion with a relatively small transverse dimension on which said coil is wound, a retainer portion at each end of said central portion and having a transverse dimension greater than the transverse dimension of said central portion for retaining the windings of said coil on said central core portion, and two poles extending from said retainer portions, said conductive member being located between said coil and said movable member when said movable member is in said first position.

An apparatus comprising:

• a movable member at least in part of ferromagnetic material
• a base having a guide surface defining a path along which said movable member moves, said movable member being movable along said guide surface from a first position due to a force acting thereon;
• a band of flexible, electrically conductive material which at least partially encircles said movable member and which is partially displace upon movement of said movable member, said band having first and second end portions;
• means for fixedly attaching said first and second end portions of said band to said base;
• an electrically conductive member at a location spaced from said movable member when said movable member is in said first position and in the path of displacement of said band, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• an electromagnet selectively operable to move said movable member along said guide surface from said first position to said second position to test the apparatus;
• and
• a cover and a chassis sealingly enclosing said base and said movable member, said cover and said chassis being made of ferromagnetic material thereby shielding said movable member from the effects of external magnetic fields.

An apparatus comprising:

• a movable member;
• a base having a guide surface defining a path along which said movable member moves, said movable member being movable along said guide surface from a first position due to a force acting thereon;
• a band of flexible, electrically conductive material which at least partially encircles said movable member and which is partially displaced upon movement of said movable member, said band having first and second end portions;
• means for fixedly attaching said first and second end portions of said band to said base;
• an electrically conductive member at a location spaced from said movable member when said movable member is in said first position and in the path of displacement of said band, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• and
• an electromagnet selectively operable to move said movable member along said guide surface from said first position to said second position to test the apparatus, said electromagnetic including a U-shaped core having poles spaced about the path of displacement of said movable member and a coil wound on said core, said movable member having a ferromagnetic insert with end faces partially defining air gaps between said insert and said poles, each of said end faces having a surface area greater than the cross-sectional surface area of said insert at a location axially inwardly from said end faces.

An apparatus comprising:

• a movable member;
• a base having a guide surface defining a path along which said movable member moves;
• a band of flexible electrically conductive material at least partially encircling said movable member and which is partially displaced upon movement of said movable membe, said band having first and second end portions, said first end portion being fixedly attached to said base;
• an electrically conductive member in the path of displacement of said band at a location spaced from said movable member and said and when said movable member and band are in a first position, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• a band tensioner applying a force to said band to tension said band, said band tensioner having a first portion connected to a side of said base under said guide surface, said band tensioner projecting outwardly of said guide surface and having a curved end portion spaced from said base, said second end portion of said band being fixed to said first portion of said band tensioner, said band extending from said first portion of said band tensioner around said curved end portion of said band tensioner toward said guide surface of said base;
• said movable member being a roller;
• and
• further comprising a chassis to which said base is mounted and an electromagentic including anon-ferromagnetic frame and a U-shaped core attached to said frame, said electromagnet having poles spaced about the path of displacement of said roller, said conductive member being located between said coil and said roller when said roller is in it first position, said chassis having a portion on which said frame is selectively fixed.

An apparatus comprising:

• a movable member;
• a base having a guide surface defining a path along which said movable member moves;
• p1 a band of flexible electrically conductive material at least partially encircling said movable member and which is partially displaced upon movement of said movable member said band having first and second end portions, said first end portion being fixedly attached to said base;
• an electrically conductive member in the path of displacement of said band at a location spaced from said movable member and said band when said movable member and band are in a first position, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete a circuit for electrical current through said conductive member and said band;
• a band tensioner applying a force to said band to tension said band, said and tensioner having a first portion connected to a side of said base under said guide surface, said band tensioner projecting outwardly of said guide surface and having a curved end portion spaced from said base, said second end portion of said band being fixed to said first portion of said band tensioner, said band extending from said first portion of said band tensioner around said curved end portion of said band tensioner toward said guide surface of said base;
• an electromagnet including a one-piece ferromagnetic core and a coil wound directly on said core, said core including a central portion with a relatively small transverse dimension on which said coil is wound, a retainer portion at each end of said central portion and having a transverse dimension greater than the transverse dimension of said central portion for retaining the windings of said coil on said central core portion, and two poles extending from said retainer portions, said conductive member being located between said coil and said movable member when said movable member is in said first position.

An apparatus comprising:

• a movable member;
• a base having a guide surface defining a path along which said movable member moves;
• band of flexible electrically conductive material at least partially encircling said movable member and which is partially displaced upon movement of said movable member, said band having first and second end portions, said first end portion being fixedly attached to said base;
• an electrically conductive member in the path of displacement of said band at a location spaced from said movable member and said band when said movable member and band are in a first position, said movable member being movable along said guide surface from said first position to a second position in which a portion of said band contacts said conductive member to complete circuit for electrical current through said conductive member and said band;
• a band tensioner applying a force to said band to tension said band, said band tensioner having a first portion connected to a side of said base under said guide surface, said band tensioner projecting outwardly of said guide surface and having a curved end portion spaced from said base, said second end portion of said band being fixed to said first portion of said band tensioner, said band extending from said first portion band tensioner toward said guide surface of said base;
• and
• including a cover and a chassis sealingly enclosing said base and said movable member, said cover and said chassis being made of ferromagnetic material thereby shielding said movable member from the effects of external magnetic fields.