Magnetic switch assembly for operation by magnetic cards

BACKGROUND OF THE INVENTION

Field of the invention

This invention relates to so-called magnetic card readers, and more particularly to an improved magnet operable switch and reader plate assembly employing a plurality of such swtiches.

Description of the prior art

In devices heretofore known which employ switchces operable from magnets embedded in a card, the card magnets are flat strips with their poles on lines parallel to the card faces. The movable magnets are supported with their poles in planes parallel to the card magnets, and are adapted for sliding or pivotal movement in such planes to close respective pairs of switch contacts. The direction of movement of such a magnet depends upon whether a card magnet adjacent thereto is in polarity opposing or attracting relation thereto.

A disadvantage in such arrangements is that a significant portion of the available magnetic fields linking aligned card and movable magnets is needed to overcome magnetic force components tending to subject the movable magnets to transverse movement. In this connection, it will be seen that when relatively fixed and movable parallel magnets are brought close together, the movable magnet tends to be drawn toward or moved apart from the fixed magnet, depending upon whether their corresponding ends are of like or opposite poles.

Still further, magnets mounted for pivotal movement have inherent bearing friction. A substantial portion of available magnetic fields linking aligned card and pivotal magnets necessarily is used to overcome such friction.

For such reasons, movable magnets frequently fail to operate properly, thereby preventing the establishment of signal information for authentic magnetic cards. Such prior art arrangements are thus not suitable for magnetic credit and security card systems which require a high degree of repeatability and reliability in operation of magnet switches in response to properly coded magnetic cards.

Summary of the invention

My invention embraces a magnetic switch wherein an evacuated envelope houses a pair of fixed contacts, and a slidable axially poled magnet and contact combination for making and breaking contact between the fixed contacts. Further, my invention embraces an assembly of a plate supporting a plurality of such switches with their magnets movable along parallel axes toward and away from one face of the plate, and also a combination therewith of a card having axially poled magnets to be aligned with such movable magnets.

I thus eliminate the prior art problems involving the loss of a significant portion of fields of aligned card and movable magnets needed for the task of overcoming magnetic and mechanical friction forces that resist the desired movement of switch magnets. Further, my assembly is one in which I eliminate the likelihood of exposure of contacts to and the contamination of contacts by dirt, moisture and the like.

Brief description of the drawing

FIGURE 1 is a perspective view of a plate for slidably supporting magnet operable switches, in accordance with my invention;

FIGURE 2 is an enlarged longitudinal sectional view of a switch of my invention wherein an evacuated bulb supports a conductive magnet for movement into and out of engagement with fixed contacts;

FIGURE 3 is a top plan view of the plate of FIGURE 1 with magnets supported therein, illustrating a pattern of orientation of the magnets;

^{4 is a fra}8^mentary sectional view of the plate of FIGURE 3 showing the magnets of FIGURE 3 in credit card disposed adjacent to the plate; and FIGURE 5 is a lonigtudinal sectional view of a modification of my switch wherein the evacuated bulb houses a conventional magnet on which a conductive contact is adapted to move into and out of engagement with fixed contacts.

Description of the preferred embodiments

Referring to FIGURES 1-4, a card 88 with embedded axially poled magnets 8» is adapted to be placed adjacent one face of a plate 90 that has openings 92 arranged in four rows 94, 96, 98, 100 of ten openings each. Fastened in each of the openings 92 is an evacuated bulb 102 which houses of movable permanent magnet 104 adjacent one end, and a pair of opposed, fixed contacts 106, 108 which extend through the other end. As shown, leads 110, 112 are connected to the external end of the contacts 106, 108. Near the end adjacent the magnet 104, the bulb is encircled by a soft iron ring 114. As shown’ the inner end of the magnet 104, which may be pointed’ is adapted to engage the confronting ends of the fixed contacts 106, 108. The magnets 104 are made conductive, as by being plated with conductive metal, so that the engagement of such a magnet with its associated fixed contacts 106, 108 establishes a direct connection between such contacts.

FIGURE 8 illustrates a plan view of the face of the plate 90 to which the flat ends of the magnets 104 extend. In FIGURE 3, these ends of the magnets are shown with the polarities distributed in accordance with a master pattern. In the particular pattern here illustrated, the magnets 104 are so poled that the outer ends of the middle two magnets in row 94 are of the same polarity (south), and the polarities of the magnets extending toward the outer ends of that row are alternating north and south poles. The same arrangement is followed in row 98. Rows 96 and 100 are similarly arranged, but with

3,474,366 the polarities of the magnets being opposite to those of the corresponding ones in the rows 94 and 98.

When the card 88 is placed with its magnets 80 aligned with respective movable magnets 104, those magnets 104 which are in polarity attracting relation to the associated card are attracted, and those in polarity opposing relation are repelled. As illustrated at the bottom of FIGURE 4, each of the reversed polarity card magnets 80 repels the associated movable magnet 104 and causes it to establish a conductive connection between the associated fixed contacts 106, 108.

In this latter connection, it is assumed the card is “coded,” in that the polarities of the faces of the card magnets adjacent the plate 90 are, except for a predetermined number (e.g., four) of them, opposite to the polarities of the ends of the movable magnets with which they are aligned. Thus, with the four magnet switches operated from the four magnets 80 which form the card code are adapted, through their associated leads 110, 112, for connection to a network to provide desired signal information identifiable with the card.

When the card 88 is removed from alongside the plate 90, the magnets 104 which had moved into conductive contact with fixed contacts 106, 108 are automatically disengaged from such fixed contacts and returned to the normal position shown in FIGURE 2. This is accomplished by the adjacent soft iron ring 114. With the force of repulsion removed by withdrawing the card from the slot, all of the magnets 104 are urged, via magnetic attraction to the soft iron rings 114, to the adjacent ends of their bulbs 102.

The bulb 102 may be made of glass or plastic. Also, the magnet 104 may be made nonconductive, but adapted to carry a conductive contact element. For example, and referring to FIGURE 4, there is shown a magnet 120 which has one end of a contact 122 secured to its inner end, e.g., as by suitable cement indicated at 124. The other end of the contact 122 is shaped to enter between and make contact with the inner ends of the contacts 106, 108.

While the magnetically controlled switches above described are arranged to function as normally open switches, it will be apparent that my invention embraces the alternative arrangement, in which the various switches are normally closed. In such case, the coded magnets in the card attract the corresponding movable magnets, thereby to open those switches. All the remaining switches remain closed as a result of repulsion by the magnets in the card. Still further, my invention will be seen to embrace the arrangements of switches wherein normally open switches are closed or normally closed switches are opened, by either repulsion or attraction.

Again referring to FIGURE 4, the leads 110, 112 extend through the ends of the openings 92 opposite the face of the plate 90 against which the card 88 is to be located. The leads 110, 112 are shown extending through openings in ablock 128 of insulation material, e.g., plastic, which is suitably secured, as by adhesive, to the ad4 jacent surface of the plate 90. As shown, one of the leads 112 of each pair is connected to a point of reference or ground potential. The remaining leads 110 are available for connection to a network as previously mentioned.

From the foregoing, it will be apparent that various modifications can be made in the structures shown and described without departing from the spirit and scope of my invention. Accordingly, I do not intend that my invention be limited, except in accordance with a reasonable interpretation of the appended claims.