GB2107915A - Transducing apparatus - Google Patents

Abstract

A "wipe-through" magnetic card reader for access-control equipment has a guide slot, one portion 14 of which is defined between two rigid plates 11 and 12. The plates are spaced apart by a dimension substantially equal to or only slightly greater than the card thickness so as to constrain the cards 6 virtually flat as they pass through the section 14. A reading head 9, preferably of magnetoresistive type, is suspended by a cantilever leaf spring 19 to intrude into the section 14 through an aperture 17 in the plate 11. <IMAGE>

Description

SPECIFICATION Transducing apparatus The present invention relates to apparatus for use in transducing magnetically-recorded information from, or onto, a card or the like token.

Particularly, though not exclusively, the invention is concerned with access-control equipment where it is required to read information from a magnetically-encoded strip on a card or the like token which is presented to the equipment and which carries information relevant to the gaining of access to a facility controlled by the equipment ~for example, entry of the token-holder to a building or other restricted area, or use of a cashdispensing machine, or some other service.Still more particularly the invention is concerned with such apparatus of the so-called "wipe-through" type, that is to say where the token is moved past or through the apparatus manually by the user as opposed to passing within the apparatus under the control of motorised conveying means, and it is an aim of the invention to provide apparatus of this type of a particularly simple and economic, though effective, form; nevertheless apparatus in accordance with the invention may also find application in conjunction with motorised or other token-conveying means, if desired.

According to one aspect of the invention, apparatus for use in transducing magneticallyrecorded information from, or onto, a card or the like token comprises a guideway for the information-carrying or receiving portion of the token, at least a section of which guideway is defined between opposed faces of two substantially rigid elements spaced apart by a dimension substantially equal to or only slightly greater than the thickness of said portion of the token, and a magnetic transducer head mounted by resilient means to be urged into contact with said portion of the token during its passage through said section of the guideway.

An embodiment of the invention in the form of a card-reading apparatus for access control equipment will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front elevation of the apparatus; Figure 2 is a side elevation of the apparatus; Figure 3 is an enlarged front view, partly in section, of the central portion of the apparatus; Figure 4 is a section on the line IV-IV of Figure 5; and Figure 5 is a view in the direction of the arrow V of Figure 3.

Referring to Figures 1 and 2, the apparatus includes a guide-housing member 1, which is advantageously an integral plastics moulding, and which in use may be mounted eg to a wall of facia 2 adjacent to a door or other closure through which access is to be controlled. The member 1 provides a flat surface 3 from which a pair of cheeks 4 and 5 upstand, the cheeks defining between them a guide slot for plastics cards 6 which are presented to the apparatus when a "request" for access is made. The member 1 is mounted so that the slot defined by the cheeks 4 and 5 is aligned vertically and, as shown in Figure 1 , the slot comprises a number of serial sections of different widths, that is to say an upper, wide section 7A which leads through a convergent section 7B to a central, narrow section 7C, and thence to a lower, wide section 7D.In use, cards 6 are presented to, and "wiped through", the apparatus in the sense of the arrows in Figure 2.

That is to say the cardholder places his card edgeon to the surface 3 within the slot section 7A and passes it downwardly, by hand, through the narrow slot section 7C (into which it is guided by the convergent section 78), and into the lower section7D from which it is then removed. During its downward travel through the section 7C a magnetically-encoded strip 8 on the card passes in proximity to a magnetic reading head 9 which transduces from the strip 8 information relevant to the gaining of access to the restricted area, this head 9 being provided in an assembly 10 which slots into a recess opening through the rear surface of the member 1.

The construction and mounting of the assembly 10 will now be described with reference to Figures 3 to 5. It comprises a parallel pair of substantially rigid plates 1 1 and 12 of eg brass, which are held apart by a spacer 13 so as to define an open-sided slot 14 which in the assembled apparatus lies within the slot section 7C defined between the cheeks 4 and 5 of member 1. The width of the slot 14 as defined between the major portions of the opposed faces of the plates 1 1 and 1 2 is slightly iess than that of section 7C and is in fact only slightly greater than the thickness of the cards 6 with which the apparatus is intended to be used.

Consequently, the information-bearing portions of the cards 6, as they are passed through the slot 14 within the section 7C, are constrained to lie virtually flat by the rigid plates 1 1 and 12, it being understood that, particularly after a period of use, the relatively thin plastics cards which are customarily used as tokens with access-control equipment tend to become somewhat bent and bowed. Furthermore, three shallow parallel tracks 1 4A-1 4C, extending in the direction of movement of the cards 6 through the slot 14, are formed on the plates 1 1 and 12, the two tracks 1 4A and 1 4C being on the plate 1 1 and the intermediate track 14B on the plate 12 opposite to the reading head 9.The spacing between the plane including the crowns of the tracks 1 4A and 1 4C, and the crown of the track 148, is equal to the nominal card thickness and the arrangement of these tracks is such that any out-of-flatness of a card as it passes through the slot 14 will tend to be convex rather than concave towards the head 9, thereby reducing the risk of separation of the encoded strip on the card from the head. The assembly of plates 1 1 and 12 and spacer 13 is bonded together with the relative alignment of the components accurately defined by a pair of dowel pins 15 and 16 passing through holes in each.

The plate 1 1 has an aperture 17 in it for the reception of the reading head 9. This head is mounted resiliently so as normally to intrude slightly into the slot 14 and to press against the magnetised strip 8 of a card 6 as it passes through the slot. Since, however, virtual flatness of the information-bearing portion of the card in its passage past the head 9 is ensured by the plates 1 1 and 12, it is unnecessary for the head mounting to be designed to enable the head to track large-scale deformations of the card or to press heavily against the card, as is the case with conventional card reading head mounts. On the contrary, a simple, robust and inexpensive mounting assembly may be employed and a head loading of say 15-25 grams is sufficient.In the illustrated embodiment the head 9 is of mangetoresistive type and is preferably as described in copending United Kingdom patent application No.8127609, although a conventional inductive type head could be employed if desired.

The head is mounted in a truncated pyramidal carrier 18 which in turn is carried by two arms 19 bent from a beryllium copper plate, in the nature of cantilever leaf springs. A knife-edge mounting 25 between the spring arms 19 and the carrier 18 confers upon the latter a small degree of pivotal movement about the axis X relative to the spring, in addition to the arcuate movement conferred by the flexibility of the arms, so that the head can track any slight deviations in a card which remain after it is 'straightened-out" by the pates 1 1 and 12.

The flat centre-section 20 of the spring plate is clamped by means of a terminal board 21, secured by a screw 22 to the plate/spacer assembly 11/12/13, and once again accurately aligned by the dowel pins 15 and 16. The board 21 is connected by a trailing electrical lead (not shown) to the head 9, and also the the remote signalprocessing part of the equipment. The whole assembly 10 is secured by two screws 23 passing through clearance holes in the plates 11 and 12 and spacer 13 and into tapped holes in an integral stub 24 extending from the rear of the member 1.

During manufacture of the reading head assembly the sensitive element(s) of the head 9 are accurately located with respect to a datum which in the assembled apparatus corresponds to the position of the dowel pin 15, so that with the edge of a card 6 in contact with the pin 15 the sensitive element(s) of the head 9 will be in correct alignment with the respective track(s) of magnetisation on the card strip 8.The pin 15 is in effect the "master" datum-defining element of the assembly 10 and when that assembly is slotted into the member 1 the pin 15 is accurately aligned to be tangential to the surface 3 before the screws 23 are tightened, so as to ensure that the track(s) of magnetisation remain in correct alignment with the sensitive element(s) of the head 9 when a card is passed through the section 7C and its edge transfers from the upper part of the surface 3 onto the pin 1 5 and back to the lower part of the surface 3.

As will be appreciated from the above the apparatus is of a simple and economic construction, can cater for bent cards without difficulty, needs only a light contact pressure between the head and card, and employs no rotating or sliding parts apart from the knife-edge mounting of the carrier 1 8 to the arms 19. In the event of foreign objects being poked into the slot 14 the chamfered edge of the carrier 18 and the flexibility of the arms 19 will permit the head assembly to retract into the aperture 17 out of harm's way. The vertical guide slot for the cards has no dirt traps and any debris which should enter will be cleared out by the next card which is passed through; rain falling onto the slot area will run straight through.

Although described above in terms of an apparatus with a transducer head for reading magnetically-encoded information from cards, a similarform of construction can of course be used for apparatus where there is a head for writing such information onto cards, or where there is a succession of reading and/or writing heads.

Claims (7)

1. Apparatus for use in transducing magnetically-recorded information from, or onto, a card or the like token comprising a guideway for the information-carrying or receiving portion of the token, at least a section of which guideway is defined between opposed faces of two substantially rigid elements spaced apart by a dimension substantially equal to or only slightly greater than the thickness of said portion of the token, and a magnetic transducer head mounted by resilient means to be urged into contact with said portion of the token during its passage through said section of the guideway.

2. Apparatus according to claim 1 wherein said transducer head is suspended at one end of cantilever spring means the other end of which is held fast in relation to said rigid elements.

3. Apparatus according to claim 1 or claim 2 wherein said transducer head is pivotally mounted to said resilient means.

4. Apparatus according to claim 3 wherein said transducer head is pivotable about an axis parallel to the longitudinal direction of said section of the guideway.

5. Apparatus according to any preceding claim wherein said opposed faces are configured such as to impart a shallow curvature to the information-carrying or receiving portion of a said token in its passage through said section of the guideway, such curvature being convex towards the transducer head.

6. Apparatus according to any preceding claim wherein said rigid elements, transducer head and resilient means are embodied together in a discrete unit mounted to a housing, which housing defines a section of said guideway to lead the information-carrying or receiving portion of a said token into the first-mentioned section thereof.

7. Transducing apparatus substantially as hereinbefore described with reference to the accompanying drawings.