WO1999039301A1

WO1999039301A1 - Read head for wiegand token

Info

Publication number: WO1999039301A1
Application number: PCT/US1999/001602
Authority: WO
Inventors: Carl Gandarillas
Original assignee: Hid Corporation
Priority date: 1998-01-29
Filing date: 1999-01-26
Publication date: 1999-08-05
Also published as: EP1050009A1; JP2002502076A; AU2562999A; US5898241A

Abstract

A read head (30) for a Wiegand wire (22) has two C-shaped ferro-magnetic yokes (40, 42) in lateral alignment with one another, two magnets (36, 38) sandwiched between respective first and second legs (32a, 32b) of the yokes, and a pickup coil (34) wound on one of the legs of the read head. One magnet has a first polarity adjacent to the first leg (32a) of the first yoke (40), the other magnet has the first polarity adjacent to the second leg (32b) of the second yoke (42), and the reluctances of the two yokes are equal. When used in combination with a processor that processes the output pulses, a Wiegand token (22) having one or more Wiegand wires therein may be detected by counting the number of output pulses of the read head (30) and ascertaining the duration of time between occurrences of those pulses. Wiegand tokens (22) having different values may have different numbers of Wiegand wires therin 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.

Description

1

READ HEAD FOR WIEGAND TOKEN BACKGROUND OF THE INVENTION

This invention relates to a read head for reading a token or coin having a Wiegand

wire therein, and is particularly directed to a read head for use in, for example, coin-operated

machines, such as gambling machines, and which is capable of detecting the insertion of such

coins/tokens by providing an electrical pulse in response to a switch in state of the Wiegand

wire in the inserted token.

The Wiegand wire is a ferro magnetic wire having core and shell portions with

divergent magnetic properties. The currently preferred type of Wiegand wire is disclosed in

U.S. Patent No. 4,247,601, issued on January 27, 1981, and which is incorporated herein by

reference. Read heads which are effective to provide an output pulse from a switch in state

of the Wiegand wire are described in U.S. Patent No. 4,263,523, issued April 21, 1981, and

U.S. Patent 4,593,209, issued June 3, 1986. A module employing the Wiegand wire that is

effective to generate a pulse in response to a change in magnetic field is described in U.S.

Patent No. 4,484,090, issued November 20, 1984.

Read heads for use with a Wiegand wire are currently employed in various access

systems. Codes are incorporated in access cards and keys where the Wiegand wire is

employed in the card or key to provide the encoding. One technique of positioning these

wires in the access card and for reading the wires as the wires are passed over the face of a

read head is described in said U.S. Patent No. 4,593,209. The manner in which the Wiegand

wires are encoded on a code strip carried in an access card is described in connection with the

discussion of Figs. 5 and 6 in said U.S. Patent No. 4,593,209. As shown therein, the "zero" bit wires are all parallel to one another in a single column like the rungs of a ladder. The

"one" bit wires are also parallel to one another in a single column. However, the center lines 2 of the two columns are spaced from one another. Thus, the zero bits are read by one portion of the read head and the one bits are read by another portion of the read head. U.S. Patent

No. 4,736,122 discloses an improved read head of those devices discussed in the patents mentioned above. As shown in Fig. 1 of U.S. Patent No. 4,736,122, the read head described

therein is E-shaped with a polarized magnet at each of the three legs and the magnets are sandwiched between a thin yoke and a thick yoke. The thin and thick yokes forming set and

reset fields, respectively.

The read head designs previously known have maximum air gap ranges that limit their

usefulness to only select applications. For example, the above-mentioned access card having

Wiegand wires therein can be read by previous read heads due to the relatively short distance between the Wiegand wires themselves and the face of the read head. Further, such read

heads are inappropriate for reading Wiegand wires that do not by themselves represent either

a zero bit or a one bit, such as Wiegand wires that are embedded within a novel coin or token.

It is therefore an object of this invention to provide a read head that has a greater air

gap range than that of previous devices.

It is another object of this invention to provide a read head that is capable of reading a

novel coin or token having one or more Wiegand wires therein.

Various other objects, advantages and features of the present invention will become

readily apparent to those of ordinary skill in the art, and the novel features will be particularly

pointed out in the appended claims.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, a read head is provided to

be used with a Wiegand wire wherein the read head responds to a field change generated

from a switch in state of the Wiegand wire to provide an output pulse. The read head includes two C-shaped ferro-magnetic yokes in lateral alignment with one another, two 3 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.

As an aspect of the present invention, the field that is produced adjacent the ends of the two legs of the first yoke is substantially equal in ampUtude and opposite in direction from

the field that is produced adjacent the ends of the two legs of the second yoke.

As another aspect of the present invention, the Wiegand token that is read includes

therein a Wiegand wire that is circular in shape so that the read head responds separately to

each magnetic field change generated from a switch in state of each of two wire segments of

the Wiegand wire in the token as the respective wire segment passes by the read head.

As a further aspect of the present invention, the read head separately detects each of a

plurality of Wiegand wires that are included within the Wiegand token.

In accordance with another embodiment of the present invention, an apparatus for

detecting a Wiegand token includes the above-mentioned read head and a processor that

processes the pulses output from the read head to identify whether or not the read head

responded to a Wiegand token.

As an aspect of this embodiment, the processor ascertains the number of output pulses

as well as the duration of time between occurrences of those pulses, and identifies the

Wiegand token from the ascertained information.

In accordance with a further embodiment of the present invention, a method of

detecting a Wiegand token having at least one Wiegand wire therein is carried out by

supplying a first magnetic field to set a magnetization of a segment of Wiegand wire,

supplying a second magnetic field to reset the magnetization of the segment of Wiegand wire, producing a respective output pulse in response to the setting and resetting of the 4 magnetization of each segment of Wiegand wire, and detecting the Wiegand token from the

produced output pulses.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and not intended to limit

the present invention solely thereto, will best be appreciated in conjunction with the

accompanying drawings, wherein like reference numerals denote like elements and parts, in which:

FIGS. 1A - ID and 1F-1G are different views of a novel token with Wiegand wire

embedded therein used in conjunction with the read head of the present invention, and Fig IE

schematically illustrates a Wiegand wire ring to be embedded in the token;

FIG. 2A is a perspective view of a token passing between two read heads in

accordance with the present invention, and FIGS. 2B and 2C schematically illustrate the

respective paths of a token that is rejected and accepted, respectively, within a device

embodying the read head of the present invention;

FIG. 3 is a perspective, partially exploded view of the read head of the present

invention;

FIG. 4 is a perspective view, partially in phantom, of another token with a Wiegand

wire embedded therein that may used in combination with the read head of the present invention; and

Figs. 5A - 5C schematically illustrate the read head of the present invention.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

The read head of the present invention may be used in conjunction with a novel token

with a Wiegand wire embedded therein, hereinafter, "Wiegand Token" or "Wiegand Wire

Token." The novel Wiegand Token is the claimed subject matter of co-pending parent

application serial no. 08/985,598, filed December 5, 1997. A discussion of the novel 5

Wiegand token is provided, followed by a discussion of the read head of the present invention.

Referring now to Figs. 1A - 1G, the novel Wiegand token essentially is a token body 10 with one or more grooves 12 therein, with a Wiegand wire 20 in the shape of a ring (Fig

IE) embedded within each groove 12. Token body 10 is flat, disk-shaped and made of any

appropriate non-magnetic material. The token body 10, together with one or more Wiegand

wires therein, is injected molded, or the like, to hold the Wiegand wires in place. A top surface 14 (shown in FIGS. 1C, ID and IF) of the Wiegand token may be applied with

custom printing. The rear surface 16 of the Wiegand token likewise may be applied with

custom printing.

The Wiegand token may be utilized in gambling or other coin-operated machines embodying the read head of the present invention. However, and unlike the known access

systems mentioned above, the Wiegand token in combination with the read head of the

present invention provides security as to authenticity, not by the particular arrangement of

one and zero bits as in an access card, but by the number of Wiegand rings and the distances

between those rings in the Wiegand token. Of course, the weight, size and shape of the

Wiegand token itself may be taken into account. In FIGS. 1A - ID, a Wiegand token is

shown as including three circular grooves in which three Wiegand wire rings are embedded.

Given a token diameter of, for example, 1.5 inches and a distance between the Wiegand wire

rings of, for example, 0.2 inches, a token having this exemplary diameter, number of rings and

particular distance between rings can be said to have a particular, e.g., monetary, value. As

another example, a 1.7 inch diameter Wiegand token having four wire rings therein, and a

ring distance of 0.1 inches can be said to have a different, predetermined monetary value.

Thus, the Wiegand token may have any desired diameter, any appropriate number of Wiegand

wire rings embedded therein and any appropriate distance between wire rings. Of course, the 6 distance between adjacent rings may be different from the distance between other adjacent rings within the same Wiegand token. Still further, the particular configuration of the

Wiegand token (i.e., size, number of rings, etc.) may represent something other than a

particular monetary value, such as a code. For example, a particular Wiegand token may represent an entry code.

The Wiegand token is for use in a coin operated machine or other device having the

novel capability of being able to identify the insertion of the Wiegand token therein. Such

novel machine may include a coin/token slot in which the Wiegand token is inserted, one or

two novel Wiegand read heads in accordance with the present invention, a coin/token

solenoid deflector and an appropriate processing system. FIG. 2A is a schematic illustration

of a Wiegand token 10 passing between Wiegand read heads 30, 40 of the present invention,

and FIGS. 2B and 2C schematically illustrate the path of an inserted coin/token, wherein the

coin/token is rejected when it is determined to be an unacceptable or non-authentic

coin/token (FIG. 2B), and the inserted coin/token is accepted when read heads 30, 40, in

conjunction with the appropriate processing system (not shown), determine that the inserted

coin/token is authentic (FIG. 2C). Hereinafter, all references to "token" are also intended to

include coins and equivalents thereto.

When a token is inserted into the coin slot of a coin operated machine embodying the

capability of detecting Wiegand tokens, the token passes by and between both read heads 30

and 40 shown in FIG. 2A. Two read heads 30, 40 of the present invention are preferably

used so as to ensure detection of the insertion of a Wiegand token having wire rings 20 only

on one side thereof (see Fig. IF). Of course, one read head of the present invention by itself

may be utilized.

The read head 30 of the present invention will now be discussed in detail with

reference to Fig. 3. The read head 40 shown in Fig 2A may be identical to read head 30. As 7 shown in FIG. 3, read head 30 includes a C-shaped core 32 having first and second legs 32a, 32b. On one of the legs, for example, leg 32b, pickup coil 34 is wound. First and second

magnets 36, 38 are sandwiched between the legs of first and second ferro magnetic C-shaped

yokes 40 and 42, respectively. As shown in FIG. 3, the north pole of magnet 38 is flush against the surface of yoke 40 and the south pole of this magnetic is flush against the surface

of yoke 42. The direction of magnetization of the other magnet 36 is opposite from that of

magnet 38 so that the south pole of magnet 36 is flush against yoke 40 and the north pole of

magnet 36 is flush against yoke 42. The result of this magnetic orientation to the legs of the

yokes is the field directions that are shown schematically in FIG. 3.

The C-shaped core 32 and coil 34 constitute read head 30, whereupon the passage of

a wire segment 22 of one of the Wiegand wire rings 20, previously discussed, past the face of

the read head in the direction and orientation, along the x-axis, shown causes the wire

segments to undergo a switch in magnetic state, inducing an electric pulse in pick-up coil 34.

In more particular detail, as wire segment 22 travels in the lateral direction shown, it first

encounters a first magnetic field due to the leakage flux across the ends of the legs of yoke 40

resulting in the magnetization of wire segment 22 so that its shell and core are magnetized in

the same direction. As wire segment 22 continues to pass across the face of read head 30 in

the x-axis direction, it encounters another magnetic field adjacent to yoke 42, which field will

be equal to but in the opposite direction from that of the field adjacent to yoke 40. The

second field causes the wire segment 22 to reset. The result of the passage of wire segment

22 over the face of read head 30 is the induction of a significant output pulse in pick-up coil

34. Read head 30 is said to be a symmetric device since yokes 40 and 42 have equal widths.

Yokes 40 and 42 thus have the same reluctance and cause an equal but opposite effect in the magnetization of the Wiegand wire. Therefore, and unlike prior art designs, both the setting

and resetting of the Wiegand wire produces a substantial and significant flux change which in 8 turn produces a useful output in pick-up coil 34. Also, the read head of the present invention produces an electric pulse of opposite polarity if the Wiegand wire passes by the face of the

read head in the opposite direction, and thus read head 30 detects the direction of motion of

the Wiegand wire.

As previously discussed, each Wiegand token has embedded therein at least one

Wiegand wire ring. Then, by causing the inserted Wiegand token 10 to pass between the

faces of read heads 30, 40 in the manner shown in FIG. 2A within an apparatus embodying the present invention, the Wiegand wire ring produces two so-called Wiegand pulses. If a

Wiegand token having three Wiegand wire rings embedded therein is inserted, six Wiegand

pulses are produced. Assuming the speed of the Wiegand token as it passes between read heads 30, 40 is known, the number of Wiegand wire rings embedded in Wiegand token 10

and the distances therebetween can be ascertained which, in turn, identifies the value of the

inserted Wiegand token. Similarly, detection of the number of Wiegand pulses as well as the

elapsed time between those pulses also identifies the value of the inserted Wiegand token.

The weight, size and shape of the Wiegand token itself also could be utilized as previously

mentioned. The particular design of the processing circuit used by the present invention and

that is capable of converting a series of pulses, taken into account the time between the

pulses, to a value is a matter of ordinary skill, and, therefore, further description thereof is

omitted herein. Acceptance or rejection of an inserted token by solenoid deflector 50 (Figs.

2B and 2C) is easily accomplished in response to the detected value, or the lack of a value, of

the inserted token. Hence, tokens and coins not having any Wiegand wires therein will be

rejected in a coin operated machine which accepts only Wiegand tokens or accepts only

Wiegand tokens having particular values.

As previously discussed, the read head of the present invention is able to detect a

Wiegand token that is, for example, circular in shape. The Wiegand wire(s) embedded within 9 the Wiegand token may be open (as shown in Fig IE) or closed, but open rings generally are

preferred as they are simpler to construct and result in no loss in performance so long as the

opening in each ring is relatively small. The ring or circular shape of the Wiegand wires that

are embedded in the Wiegand token provides the advantageous feature that the Wiegand

token can be inserted into a coin slot at any orientation. Such Wiegand wire rings also are

relatively easy to construct from Wiegand wire that is produced, for example, in the manner disclosed in the U.S. Patents previously mentioned. Accordingly, a process of manufacturing

Wiegand tokens is carried out by forming or purchasing a token that is made from any non¬

magnetic material, forming one or more circular grooves in one side of the token (see FIG.

IB), the grooves preferably being concentric, inserting or embedding an open or closed

shaped Wiegand wire ring in each of the grooves, injecting a mold within the grooves to hold

the Wiegand wire rings in place, or other equivalent, and optionally custom printing the face

of the resultant token (e.g., print the value of the token thereon), or adhere an appropriate

label to one or both faces of the token. Of course, other manufacturing methods may be used so long as the resultant Wiegand token has at least one Wiegand wire ring therein. In any

case, the read head of the present invention is capable of detecting any number of types of

Wiegand tokens, such as circular-shaped tokens, non circular- shaped tokens, tokens having

one or more Wiegand wires embedded only on one face thereof, etc.

The use of one or two read heads of the present invention may detect tokens having

Wiegand wires embedded near both faces thereof. The Wiegand wire rings embedded in the

two faces may be arranged at the same location and, thus, only one read head 30 would be

needed in a device to detect the insertion of a Wiegand token. Alternatively, the location of

the Wiegand wire rings in the two faces of the Wiegand token may be different resulting in a

different detected value of the token depending upon the orientation of the token upon insertion into the device. 10

The read head of the present invention also may detect tokens and equivalents thereof

that have non-circular shapes and/or that are not relatively flat. The read head can detect a Wiegand token with a square shape, a rectangular shape, etc., whereupon a square shaped, a

rectangular shaped, a round shaped, etc., Wiegand wire is embedded therein. Fig. 4 is a perspective view of a Wiegand token 60 having a rectangular shape with a straight Wiegand

wire 62 (shown in phantom) therein. The rectangular Wiegand token shown will be detected

by the read head of the present invention provided the token is inserted in a particular

orientation, such as by providing an insertion slot with an appropriate width and depth.

These various shaped Wiegand tokens may be useful in various types of machines, such as

gambling devices, entry devices, security devices, teaching devices, etc., and thus the read

head of the present invention may be embodied in any number of devices.

While the present invention has been particularly shown and described in conjunction

with a preferred embodiment thereof it will be readily appreciated by those of ordinary skill

in the art that various changes may be made without departing from the spirit and scope of

the invention. For example, Figs. 5 A - 5C are exemplary schematic illustrations showing a

particular design and dimensions of the read head of the present invention, but the present

invention is not limited to this particular design and may have other designs that embody the

present invention.

As another example, although the present discussion is directed to a read head that is

capable of detecting a Wiegand token, the read head of the present invention may detect a

Wiegand wire not embedded within a token. As a further example, the read head of the

present invention also may be utilized to detect other types of magnetic devices.

Therefore, it is intended that the appended claims be interpreted as including the

embodiments described herein, the alternatives mentioned above, and all equivalents thereto.

Claims

11WHAT IS CLAIMED IS:

1. A read head for use with a Wiegand wire wherein the read head responds to a field change generated from a switch in state of the Wiegand 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

reluctances of said first and second yokes are equal.

2. 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 amphtude and opposite in direction

from the field produced adjacent the ends of said first and second legs of said second yoke.

3. The read head of claim 1 in combination with a token having a Wiegand wire

embedded therein, wherein the read head produces an output pulse when the token passes by

said read head. 12

4. The combination of claim 3, wherein said Wiegand 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 Wiegand wire in said token as the respective wire segment passes by said read head.

5. The read head of claim 1 in combination with a token having a plurality of

Wiegand wires embedded therein; wherein said read head responds separately to each

magnetic field change generated from a switch in state of each of said Wiegand wires in said

token as the respective Wiegand wire passes by said read head.

6. The combination of claim 5, wherein each of said Wiegand 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 Wiegand wires in said token as the respective wire segment of the respective Wiegand

wire passes by said read head.

7. The combination of claim 6, wherein said plurality of Wiegand wires in said token

are concentrically ahgned such that said read head produces a first pulse when a first segment

of a first of said Wiegand wires passes by said read head, followed by a second pulse when a

first segment of a second of said Wiegand wires passes by said read head, followed by a third

pulse when a second segment of said first Wiegand wire passes by said read head, followed by

a fourth pulse when a second segment of said second Wiegand wire passes by said read head.

8. Apparatus for detecting a Wiegand token, comprising: a read head for responding to a field change generated from a switch in state of a 13

Wiegand wire embedded in a Wiegand token as said Wiegand 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 Wiegand token .

9. The apparatus of claim 8, wherein said read head produces an output pulse each

time a segment of Wiegand wire embedded in said Wiegand token passes by said read head; and said processing means detects the Wiegand token from the output pulses produced by said read head.

10. The apparatus of claim 9, wherein said processing means detects the Wiegand

token from the time duration between occurrences of each of the output pulses produced by said read head.

11. 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 Wiegand

wires embedded in a Wiegand token as the respective segment of the respective Wiegand

wire passes by said read head.

12. 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 Wiegand wire; and said processing means identifies the Wiegand token by the number of

output pulses produced by said read head and the time duration between occurrences of said output pulses. 14

13. 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.

14. 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 amphtude and opposite in

direction from the field produced adjacent the ends of said first and second legs of said

second yoke.

15. A method of detecting a Wiegand token having at least one Wiegand wire

therein, comprising the steps of:

supplying a first magnetic field to set a magnetization of a segment of Wiegand wire;

supplying a second magnetic field to reset the magnetization of the segment of Wiegand wire;

producing a respective output pulse in response to the setting and resetting of the

magnetization of each segment of Wiegand wire; and

detecting the Wiegand token from the produced output pulses. 15

16. The method of claim 15, wherein said Wiegand wire in said Wiegand 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 Wiegand wire.

17. 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 Wiegand token from the ascertained time duration.

18. The method of claim 15, wherein a respective output pulse is produced in said

producing step for each of a plurality of Wiegand wires in said Wiegand 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 Wiegand token

from the identified number of produced output pulses and the ascertained time durations.