IE911703A1 - A contact device for a switch - Google Patents

Abstract

The respective switch is used in a unit in which data media are inserted and/or removed. The switch (28) is used as a signal transmitter and is allocated directly to a wall (12) which carries the data media, to be precise such that the contact elements, a leafspring (32) and a loop spring (33) are arranged in a self-locking manner in links (35, 36, 37, 40, 41, 43, 44, 46) which are formed out on the wall (12). A roller (30), which is supported on the limb (34) of the loop spring (33) which interacts with the leafspring (32), is provided as the operating element. The contact elements (32, 33) make contact with a conduction strip (48) by means of a claw connection which permits only one insertion movement.

Description

The invention relates to a contact device for a switch, which serves to recognise a flat object, for instance a data carrier, being inserted into or removed from an appliance. The switch is positioned on the opposite side of a wall of the appliance which guides the data carrier, and an actuation member extending through the guide wall is associated with the switch.

In data-gathering appliances in the most general sense, i.e. in data-gathering instruments where data input and/or data output takes place by means or more or less thick but nonetheless flat data carriers which have a degree of stiffness, several switches may be provided, associated with a guide passage or an insertion/removal opening, this being normally slot-shaped. The switches serve for sensing and recognition of insertion or withdrawal and removal of a data carrier.

By means of such a recognition function, the data carriers can be counted in a very simple manner, or the individual insertions can be stored in the memory in order to be able to ascertain for example, the degree of usage of a data card, or the transport means can be switched on or off and the controlling, reading and recording - 2 IE 911703 means can be put into and taken out of operation. One example of this would be the tachograph, in which the tachograph chart, which serves as a recording medium, is inserted through a frontal slot and is automatically transported to the recording position. However, the recording members can only come into contact with the tachograph chart when the latter is positioned in the appliance at the correct time.

In addition, the switch in question has the task, upon repeated removal/insertion, compulsory upon a change of driver and police inspections, of recording a suitable marking on the relevant tachograph chart.

Also included among appliances of this type are apparatus into which which money can be automatically lodged or from which money can be dispensed, in which banknotes, coins, credit cards, tickets, or tokens of value may be used. Ticket dispensers and cancelling machines, receipt printers and appliances which process receipts and other printed matter, appliances with storage cartridges for data transport, or appliances in which identity cards and permits only have a key function, should also be mentioned.

What is essential is that switches of a type which perform a sensing function should operate reliably in all circumstances, particularly outside self-contained enclosures, e.g. in vehicles, in parking ticket dispensers, pay phones and automated petrol pumps, and that they should be capable of being manufactured and assembled in a manner suited to mass production without too great an expense.

The use of photoelectric barriers, although possible, is not always appropriate, as photoelectric barriers are relatively expensive items and, apart from the constant power supply required, have operational risks due to becoming dirty.

Thus it is an object of the invention to provide an electrical switch of a kind which will withstand high demands of operational reliability and be capable of being mass produced, and which will be universally usable because of its small space - 3 IE 911703 requirement.

According to the invention, there is provided a contact device for a switch, serving in apparatus for recognition of insertion or withdrawal of a flat member, for example a data carrier, the contact device being positioned on the opposite side of a wall of the apparatus which guides the data carrier and an actuation member being associated with the device, the actuation member extending through the guide wall, wherein one contact element of the switch is formed as a leaf spring and a further contact element is formed as a coil spring, the coil spring is mounted on a spigot formed on the guide wall parallel to the guide wall, and the contact elements are associated with one another in such a manner that a geometrical plane defined by the position of a limb of the coil spring and extending perpendicular to the guide wall, cuts the leaf spring in its longitudinal direction.

In a preferred embodiment of the invention, the limb of the coil spring which cooperates with the leaf spring is disposed substantially parallel to the guide wall and it is formed to be longer than the leaf spring, and the actuation member engages against the limb of the coil spring. The actuation member is suitably formed as a roller and the roller may be rotatably mounted on the contact-establishing limb of the coil spring. In addition to the spigot for reception of the coil portion of the coil spring, structures are preferably formed on the guide wall for lateral constraint of the limbs of the coil spring and for self-retention of the leaf spring by virtue of its spring characteristics. According to a further feature of the preferred embodiment, the non-contact-establishing limb of the coil spring and the non-contact-establishing end of the leaf spring are formed as spring-like claws for effecting contact between the switch and a flexible strip conductor.

The solution is optimised from a production engineering point of view in that the two contact springs which form the switch can be inserted into holding devices formed directly on the wall guiding the data carrier and that a solderless connection to a - 4 IE 911703 conductor strip is provided, and can be thus realised without any very great expense. The production engineering advantage is given particularly in that the function of the preferably wire and strip contact combination is largely independent of tolerances. The space requirement is also considerably reduced and several switches or a bank of switches can quite easily be formed.

It is further advantageous that without providing actual contacts, the contact springs touch each other point-wise in establishing contact, in that the wire-form limb of the coil spring cooperates with the bent end of the leaf spring. In addition, the contact springs are arranged in such a manner that there is a sliding effect between the contact springs when the switch is actuated.

Thus automatic cleaning of the contact springs results from each contacting action. A particularly novel embodiment which is especially effective for less stiff data carriers further consists in the provision of a roller as actuation member and positioning this in a rotatable manner directly on the contact-effecting limb of that contact spring of the switch which is formed as a coil spring.

In the following text, the invention is explained in greater detail having regard to the drawings.

Figure I shows a schematic part side view of a tachograph with a frontal insertion/removal slot for the tachograph chart, which functions as a recording medium; Figure 2 shows a section of a guide passage for a tachograph chart on the section line I of Figure 1, with a top view of the contact device according to the invention, to an enlarged scale compared with Figure 1; and Figure 3 shows in section the contact device on the section line II-II of Figure 2, but in a non-actuated state by contrast with Figure 2.

The schematic, part side view of Figure 1 depicts a tachograph having a housing 1, a front window 2, which covers the - 5 IE 911703 display means situated in a window cut-out 3 in the front wall 4 of the housing 1, and frontally accessible insertion/removal slots 5, 6 for the tachograph chart 7, used by the driver and co-driver as a recording medium or data carrier. The tachograph is formed as a self-contained device, which can be used in a modular manner and can be fitted into the instrument-panel of a motor vehicle, flush with the front surface of the panel.

In Figure 1, reference 8 denotes a dial face which covers the window cut-out 3 of the housing 1. An indicator (not shown) for vehicle speed, engine r.p.m. and display of time is located in known manner in the pot-shaped depression 9 in the dial face. Adjusting knobs, one of which is shown in Figure 1 and denoted by reference 10, serve for dialing various types of operating time relating to the driver. A holder is denoted by reference 11, this cooperating with 12, 13 and 14, 15 to define a frame which forms two passages 16 and 17. Holder 11 is secured in the housing 1 of the tachograph. Transport rollers and associated opposed rollers arranged in pairs 18, 19 and 20, 21 engage through openings in the guide walls 12, 13 and 14, 15, these openings not being described in greater detail.

Figure 1 further shows that cylindrical rods 22, 23 and 24, 25 are positioned behind the insertion and removal slots 5, 6, these rods serving as sealing bodies and being mounted in a radially movable manner in recesses 26 and 27 provided in the holder 11.

An individual switch 28 and 29 is assigned to each of the passages 16 and 17. Each switch, together with a respective actuation member, in this case a roller 30 or 31, extends into the respective passage 16 and 17 and therefore into the path of movement of the tachograph chart.

As shown in Figure 2, one of the contact elements of the switch 28 shown in Figure 2 is formed as a leaf spring 32, while the other contact element is formed by a coil spring 33. Both contact elements are mounted, without additional securing means, in structures formed on the guide wall 12 of the passage 16. The contact elements are mounted in such a manner that a geometrical - 6 IE 911703 plane extending perpendicular to the guide wall 12 and containing the contact-establishing leg 34 of the coil spring 33, cuts the leaf spring 32 in a longitudinal direction.

A spigot 35 is provided on the guide wall 12, parallel to the wall, for receiving the coil spring 33 or the coiled portion of the coil spring. In addition, the contact-establishing leg 34, which extends substantially parallel to the guide wall 12, is guided in a slot 36, which is formed in a side-wall portion 37 formed on the guide wall 12. The non-contact-establishing leg 38 of the coil spring 33 is formed as a claw 39, as can be seen more clearly from Figure 3, and is held in a pocket 40, which is formed in a wall projection 41.

The leaf spring 32, which is formed in a manner suited to self-retention by virtue of its spring characteristics, is associated with bearing blocks 42 and 43, each formed on the guide wall 12, and with a bridge 44. In addition, a pocket 46 in the wall projection 41 is associated with an arm 45 formed on the leaf spring 32. The arm 45 of the leaf spring 32 is formed as a claw 47 similarly to the limb 38 of the coil spring 33. The ends of the claws 39 and 47 lie substantially in line and extend into the insertion path of a flexible strip conductor 48, when in an installed condition. The strip conductor 48 is guided at least along its sides between the guide wall 12 and the wall projection 41 by suitable recessing of the wall projection 41 and is secured against being pulled out by the opposing barb-type action of the claws 39 and 47, which dig into the strip conductor 48 when it is being inserted. There is effected at the same time contact between the contact elements of the switch 28, the leaf spring 32 and the coil spring 33, and conductive tracks 49 and 50, which are embedded in the strip conductor 48, the ends of the conductive tracks 49 and 50 being widened out, for the purpose of ensuring contact.

In the sectional view of Figure 3, the switch 28 is in a non-operative state, i.e. there is no tachograph chart in the passage 16 and the contact-establishing limb 34 is withdrawn from the preferably bent end 51 of the leaf spring 32. In this condition, - 7 IE 911703 the roller 30, which is provided as actuation member in the preferred embodiment and which, according to the invention, is mounted on the contact-establishing limb 34, lies at the bottom of a recess 52 in the guide wall 13 under the effect of the loop spring 33. The roller 30 thereby extends through an opening 53 in the guide wall 12 into the passage 16 and is guided at its sides on the one hand by the side wall portion 37 and on the other hand by opposing bearings 54 and 55. A protruding portion formed on the guide wall 12 is denoted by reference 56.

In order to complete the picture, it must also be mentioned that the actuation member may be wedge-shaped and mounted in a movable manner, particularly when greater forces and accordingly rigid data carriers, such as data cards, are used in the appliance in question.

Claims (7)

1. A contact device for a switch, serving in apparatus for recognition of insertion or withdrawal of a flat member, for example a data carrier, the contact device being positioned on the opposite side of a wall of the apparatus which guides the data carrier and an actuation member being associated with the device, the actuation member extending through the guide wall, wherein one contact element of the switch is formed as a leaf spring and a further contact element is formed as a coil spring, the coil spring is mounted on a spigot formed on the guide wall parallel to the guide wall, and the contact elements are associated with one another in such a manner that a geometrical plane defined by the position of one of the limbs of the coil spring and extending perpendicular to the guide wall, cuts the leaf spring in its longitudinal direction.

2. A contact device according to Claim 1, wherein the limb of the coil spring wlich cooperates with the leaf spring is disposed substantially parallel to the guide wall, and is formed to be longer than the leaf spring, and the actuation member engages against said limb of the coil spring.

3. A contact device according to Claim 1, wherein the actuation member is formed as a roller and the roller is rotatably mounted on the contact-establishing limb of the coil spring.

4. A contact device according to Claim 1, wherein in addition to the spigot for reception of the coil portion of the coil spring, structures are formed on the guide wall for lateral constraint of the limbs of the coil spring and for self-retention of the leaf spring by virtue of its spring characteristics.

5. A contact device according to Claim 1, wherein the non-contact-establishing limb of the coil spring and the non-contact-establishing end of the leaf spring are formed as spring-like claws for effecting contact between the switch and a flexible strip conductor. - 9 IE 911703

6. A contact device substantially as described herein with reference to and as shown in the accompanying drawings.

7. A switch comprising a contact device substantially as described herein with reference to and as shown in the accompanying drawings.