Conductive strip detector
First Claim
1. A conductive strip detector comprising a housing having front and rear ends and supporting an elongate, electrically conductive element wherein an electrically conductive part of the front end of the housing defines an electrically conductive member, the electrically conductive element and the electrically conductive member being spaced laterally in a first direction, the elongate dimension of the element extending in a second direction, and the first and second directions extending in a plane, the plane being substantially orthogonal to an axis extending between said front and rear ends of said housing;
- and means disposed in the housing for monitoring changes in the capacitance of a capacitor formed by the housing and the element when an electrically conductive strip is moved in a direction substantially parallel to said plane and past the element and for indicating when the change in capacitance is due to the presence of an electrically conductive strip.
2 Assignments
0 Petitions
Accused Products
Abstract
A conductive strip detector comprises a capacitor defined by an elongate, electrically conductive element (5) and a laterally spaced, electrically conductive member (1). Monitoring circuitry (15,16) monitors changes in the capacitance of the capacitor when an electrically conductive strip substantially parallel with the element is passed by the capacitor and indicates when a change in capacitance is due to the presence of an electrically conductive strip.
28 Citations
22 Claims
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1. A conductive strip detector comprising a housing having front and rear ends and supporting an elongate, electrically conductive element wherein an electrically conductive part of the front end of the housing defines an electrically conductive member, the electrically conductive element and the electrically conductive member being spaced laterally in a first direction, the elongate dimension of the element extending in a second direction, and the first and second directions extending in a plane, the plane being substantially orthogonal to an axis extending between said front and rear ends of said housing;
- and means disposed in the housing for monitoring changes in the capacitance of a capacitor formed by the housing and the element when an electrically conductive strip is moved in a direction substantially parallel to said plane and past the element and for indicating when the change in capacitance is due to the presence of an electrically conductive strip.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Security document handling apparatus including a conductive strip detector comprising a housing having front and rear ends supporting an elongate, electrically conductive element wherein an electrically conductive part of the front end of the housing defines an electrically conductive member, the electrically conductive element and the electrically conductive member being spaced laterally in a first direction, the elongate dimension of the element extending in a second direction, and the first and second directions extending in a plane substantially orthogonal one to an axis extending between said front and rear ends of said housing;
- and means disposed in the housing for monitoring changes in the capacitance of a capacitor formed by the housing and the element when an electrically conductive strip is moved in a direction substantially parallel to said plane and past the element and for indicating when a change in capacitance is due to the presence of an electrically conductive strip, and a document feed system for feeding documents carrying metallic strips past said detector.
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12. Security document handling apparatus including a conductive strip detector comprising a housing supporting an elongate, electrically conductive element wherein an electrically conductive part of the housing defines an electrically conductive member, the electrically conductive element and the electrically conductive member being spaced laterally in a first direction;
- and means disposed in the housing for monitoring changes in the capacitance of a capacitor formed by the housing and the element when an electrically conductive strip is moved in a direction substantially parallel to the first direction and past the element and for indicating when a change in capacitance is due to the presence of an electrically conductive strip, and a document feed system for feeding documents carrying metallic strips past said detector, said feed system feeding documents such that the relative positions of the detector and the document under examination are such that the long axis of the sensing element is substantially parallel to that of the strip, and the relative motion between the strip and the element is substantially normal to this axis.
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13. A method of detecting an electronically conductive strip using a conductive strip detector comprising a housing supporting an elongated, electrically conductive element wherein an electrically conductive part of the housing defines an electrically conductive member, the electrically conductive element and the electrically conductive member being spaced laterally in a first direction;
- and means disposed in the housing for monitoring changes in the capacitance of the electrically conductive member and the electrically conductive element when an electrically conductive strip is moved in a direction substantially parallel with the first direction and past the element and for indicating when a change in capacitance is due to the presence of an electrically conductive strip, the method comprising passing an electrically conductive strip by said electrically conductive element, the long axis of the element being substantially parallel to that of the strip, and the relative motion between the strip and the element being substantially normal to this axis, the dimension of the element along an axis normal to its long axis being substantially the same as or smaller than the dimension of the strip along an axis normal to its long axis;
monitoring changes in the capacitance of said capacitor; and
indicating the presence of an electrically conductive strip if the change in capacitance satisfies predetermined conditions. - View Dependent Claims (14, 15, 16, 17)
- and means disposed in the housing for monitoring changes in the capacitance of the electrically conductive member and the electrically conductive element when an electrically conductive strip is moved in a direction substantially parallel with the first direction and past the element and for indicating when a change in capacitance is due to the presence of an electrically conductive strip, the method comprising passing an electrically conductive strip by said electrically conductive element, the long axis of the element being substantially parallel to that of the strip, and the relative motion between the strip and the element being substantially normal to this axis, the dimension of the element along an axis normal to its long axis being substantially the same as or smaller than the dimension of the strip along an axis normal to its long axis;
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18. A conductive strip detector for use in detecting conductive threads in documents, which comprises:
- a housing;
a plurality of elongate, electrically conductive elements supported in the housing, the housing having a conductive part defining an electrically conductive member, the electrically conductive elements and the electrically conductive members being spaced laterally in a first direction; and
means disposed in the housing for monitoring changes in the capacitances of capacitors formed by the housing and the elements when a document having conductive threads is moved in a direction substantially parallel to the first direction and past the elements and for indicating when changes in the capacitances of the capacitors are due to the presence of metal threads to thereby provide thread detection in a plurality of areas of the document at the same time. - View Dependent Claims (19, 20, 21, 22)
- a housing;
Specification