Patent US5898241A successfully refreshed from Google Patents.
US5898241A
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Read head for Wiegand token
Assignee: Assa Abloy AB
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Filing: 1998-01-29
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Granted: 1999-04-27
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Expires: 2018-01-29
Abstract
Abstract A read head for a Wiegand wire has two C-shaped ferro-magnetic yokes in lateral alignment with one another, two magnets sandwiched between respective first and second legs-of the yokes, and a pickup coil wound on one of the legs of the read head. One magnet has a first polarity adjacent to the first leg of the first yoke, the other magnet has the first polarity adjacent to the second leg of the second yoke, and the reluctances of the two yokes are equal. When used in combination with a processor that processes the output pulses, a Wiegand token having one or more Wiegand wires therein may be detected by counting the number of output pulses of the read head and ascertaining the duration of time between occurrences of those pulses. Wiegand tokens having different values may have different numbers of Wiegand wires therein and/or different spacings between the Wiegand wires within the Wiegand token and, thus, the read head in combination with a processor can identify Wiegand tokens of different values.
Inventors
- 👤 Carl Ganderillas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:42
CPC Classifications
G; G07; G07F; G07F1/00; G07F1/06; G07D; G07D5/00; G07D5/08; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
150 words
A read head for use with a ferro-magnetic wire having a core and a shell with independent magnetic properties wherein the read head responds to a field change generated from a switch in state of the wire to provide an output pulse, comprising: first and second C-shaped ferro-magnetic yokes in lateral alignment with one another, each of said yokes having first and second legs; first and second magnets sandwiched between the respective first and second legs of said yokes, said magnets and said yokes providing a magnetized core having first and second legs, a pickup coil wound on one of said first and second legs of said core, said first magnet having a first polarity adjacent to said first leg of said first yoke, said second magnet having said first polarity adjacent to said second leg of said second yoke, and reluctance of said first and second yokes are equal.
Claim 2
Dependent Claim
150 words
A read head for use with a ferro-magnetic wire having a core and a shell with independent magnetic properties wherein the read head responds to a field change generated from a switch in state of the wire to provide an output pulse, comprising: first and second C-shaped ferro-magnetic yokes in lateral alignment with one another, each of said yokes having first and second legs; first and second magnets sandwiched between the respective first and second legs of said yokes, said magnets and said yokes providing a magnetized core having first and second legs, a pickup coil wound on one of said first and second legs of said core, said first magnet having a first polarity adjacent to said first leg of said first yoke, said second magnet having said first polarity adjacent to said second leg of said second yoke, and reluctance of said first and second yokes are equal.
Claim 3
Dependent Claim
49 words
The read head of claim 1, wherein the field produced adjacent the ends of said first and second legs of said first yoke is substantially equal in amplitude and opposite in direction from the field produced adjacent the ends of said first and second legs of said second yoke.
Claim 4
Dependent Claim
43 words
The read head of claim 1 in combination with a token having a ferro-magnetic wire having a core and a shell with independent magnetic properties embedded therein, wherein the read head produces an output pulse when the token passes by said read head.
Claim 5
Dependent Claim
56 words
The combination of claim 3, wherein said wire embedded in said token is substantially circular in shape, and said read head responds separately to each magnetic field change generated from a switch in state of each of two wire segments of said wire in said token as the respective wire segment passes by said read head.
Claim 6
Dependent Claim
67 words
The read head of claim 1 in combination with a token having a plurality of ferro-magnetic wires embedded therein, each of said wires having a core and a shell with independent magnetic properties; wherein said read head responds separately to each magnetic field change generated from a switch in state of each of said wires in said token as the respective wire passes by said read head.
Claim 7
Dependent Claim
64 words
The combination of claim 5, wherein each of said wires embedded in said token is substantially circular in shape, and said read head responds separately to each magnetic field change generated from a switch in state of each of two wire segments of each of said wires in said token as the respective wire segment of the respective wire passes by said read head.
Claim 8
Dependent Claim
96 words
The combination of claim 6, wherein said plurality of wires in said token are concentrically aligned such that said read head produces a first pulse when a first segment of a first of said wires passes by said read head, followed by a second pulse when a first segment of a second of said wires passes by said read head, followed by a third pulse when a second segment of said first wire passes by said read head, followed by a fourth pulse when a second segment of said second wire passes by said read head.
Claim 9
Dependent Claim
91 words
Apparatus for detecting a token having embedded therein a ferro-magnetic wire having a core and a shell with independent magnetic properties, comprising: a read head for responding to a field change generated from a switch in state of said wire embedded in said token as said token passes by said read head; and processing means for processing the output of said read head to identify whether or not said read head responded to a token having embedded therein a ferro-magnetic wire having a core and a shell with independent magnetic properties.
Claim 10
Dependent Claim
91 words
Apparatus for detecting a token having embedded therein a ferro-magnetic wire having a core and a shell with independent magnetic properties, comprising: a read head for responding to a field change generated from a switch in state of said wire embedded in said token as said token passes by said read head; and processing means for processing the output of said read head to identify whether or not said read head responded to a token having embedded therein a ferro-magnetic wire having a core and a shell with independent magnetic properties.
Claim 11
Dependent Claim
45 words
The apparatus of claim 8, wherein said read head produces an output pulse each time a segment of said wire embedded in said token passes by said read head; and said processing means detects the token from the output pulses produced by said read head.
Claim 12
Dependent Claim
29 words
The apparatus of claim 9, wherein said processing means detects the token from the time duration between occurrences of each of the output pulses produced by said read head.
Claim 13
Dependent Claim
48 words
The apparatus of claim 8, wherein said read head separately responds to a field change generated from a switch in state of each segment of each of a plurality of wires embedded in a token as the respective segment of the respective wire passes by said read head.
Claim 14
Dependent Claim
60 words
The apparatus of claim 11, wherein said read head produces a respective output pulse in response to each field change generated from a switch in state of each segment of each wire; and said processing means identifies the token by the number of output pulses produced by said read head and the time duration between occurrences of said output pulses.
Claim 15
Dependent Claim
117 words
The apparatus of claim 8, wherein said read head comprises: first and second C-shaped ferro-magnetic yokes in lateral alignment with one another, each of said yokes having first and second legs; first and second magnets sandwiched between the respective first and second legs of said yokes, said magnets and said yokes providing a magnetized core having first and second legs, a pickup coil wound on one of said first and second legs of said core, said first magnet having a first polarity adjacent to said first leg of said first yoke, said second magnet having said first polarity adjacent to said second leg of said second yoke, and reluctances of said first and second yokes are equal.
Claim 16
Dependent Claim
48 words
The apparatus of claim 13, wherein the field produced adjacent the ends of said first and second legs of said first yoke is substantially equal in amplitude and opposite in direction from the field produced adjacent the ends of said first and second legs of said second yoke.
Claim 17
Independent Claim
87 words
A method of detecting a token having at least one ferro-magnetic wire having a core and a shell with independent magnetic properties therein, comprising the steps of: supplying a first magnetic field to set a magnetization of a segment of said wire; supplying a second magnetic field to reset the magnetization of the segment of said wire; producing a respective output pulse in response to the setting and resetting of the magnetization of each segment of said wire; and detecting the token from the produced output pulses.
Claim 18
Independent Claim
87 words
A method of detecting a token having at least one ferro-magnetic wire having a core and a shell with independent magnetic properties therein, comprising the steps of: supplying a first magnetic field to set a magnetization of a segment of said wire; supplying a second magnetic field to reset the magnetization of the segment of said wire; producing a respective output pulse in response to the setting and resetting of the magnetization of each segment of said wire; and detecting the token from the produced output pulses.
Claim 19
Dependent Claim
40 words
The method of claim 15, wherein said wire in said token is substantially circular in shape, and output pulses are produced in response to the setting and resetting of the magnetization of two different segments of the same circular wire.
Claim 20
Dependent Claim
32 words
The method of claim 15, wherein said detecting step is carried out by ascertaining a time duration between occurrences of said output pulses, and identifying the token from the ascertained time duration.
Claim 21
Dependent Claim
67 words
The method of claim 15, wherein a respective output pulse is produced in said producing step for each of a plurality of wires in said token, and said detecting step is carried out by identifying the number of produced output pulses, ascertaining time durations between occurrences of said output pulses, and identifying the token from the identified number of produced output pulses and the ascertained time durations.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-04-26 | 2002-10-26 | 2003-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-26 | 2006-10-26 | 2007-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-04-26 | 2010-10-26 | 2011-04-27 | $7700.00 | Window Closed / Lapsed |