METHOD AND INSTALLATION TO FIT OUT FLEXIBLE FILMS EQUIPPED WITH ELECTRIC CONDUCTORS

This invention is relating to a method for fitting or mounting contact elements on the extremities of a set of flat conductors that are aligned one next to the other, like cables or tracks, which are worked lengthwise into flexible films and which are usually used for transmission of electric signals or data information.

In practice, such flexible films are applied in the most diverse electric and electronic fields, such as for instance car or computer industries.

Tools and instruments that make it possible to fit electrically conductive contacts onto the extremities of each of the aligned conductive tracks or conductive cables of a flexible film exist already.

These instruments or installations are based on the principle that the end of the flexible film, and thus of the conductive tracks, is moved laterally in front of a fixed installation for the fitting or mounting of the contact elements.

The method used hereby consists in the lateral displacement, one by one, of each flat conductive track or each conductive cable of the flexible film into a fixed application device in which a contact element is fitted onto the end of each conductive track or each conductive cable. This fitting has to be carried out in such a manner that a thorough mechanical and electrical connection is established between the contact elements and the conductive flat track or the conductive cable of the flexible film.

The method of such installations consists in principle by the following steps:

- the flexible film is attached to a table by means of a clamp such that the film follows the movement and position of the table. This table can move sideways to the left or to the right.

- the installation providing the mounting of the contact element onto a conductive track of the film or the fitting machine ensures that, each time a track is presented, a contact element is attached onto the end of the track; to this end, contact elements are fed automatically coming from a feed coil, and they are cut off of their supporting strip during their mounting onto the conductive track.

- the position of the conductive tracks is detected and recorded by means of optical means. This ensures that the table can position the film very precisely, so that every contact element can be mounted in the middle of each corresponding track.

- the flexible film is positioned lengthwise by means of a stop ensuring the correct position of the contact elements with respect to the edge of the film.

- by means of a programmed control of the positioning of the film on the table and of the feeding of the contact elements, the mounting of the contact elements onto the conductive tracks of the film can be synchronised and the film can be fitted out automatically with these contact elements.

This method, however, has several disadvantages, such as:

- it is impossible to align the optical detection with the transfer position of the contact element onto the film, which can give rise to problems with regard to the accuracy of the mutual positions;

- short flexible films, which emerge from the middle of a big panel cannot be presented causing the film to lie on the table and be positioned against the stop;

- as a result of the positioning of the detection means the distance between the stop and the film clamp is much too big and the method does not allow for the fixation of the structure and the conductive tracks prior to the mounting of the contact elements;

- the placement and withdrawal of the flexible film, fitted out with contact elements, happens in the application device, giving rise to possible problems, both during placement and withdrawal, such as contacts getting caught on parts of the application device. The result is inconvenience and loss of time;

- the feeding of contact elements always proceeds from left to right or vice versa, a change in feed direction is not possible.

The purpose of the invention is to eliminate these disadvantages and propose a method that is moreover a lot faster and more efficient. The option is also offered to realise a broad range of applications. The software also allows for the fixation of each flexible film type or variant (dimension, composition, nature) and for the storage thereof in a database for possible future use.

The method and means used to achieve this purpose are presented in the claims following the description of an embodiment of a method according to the invention.

This embodiment is being described with reference to the attached figures, with:

figure 1 being a schematic view of an installation for fitting out the end of a flexible film with contacts;

figures 2 to 8 being illustrations of the different consecutive steps of the method for fitting out a flexible film according to the invention;

figure 9 being a top plan view of a flexible film with contacts fitted onto it;

figure 10 being a partial cross-section of the end of the flexible film from figure 9;

figure 11 shows a flexible film equipped with contacts and the contact housing that is attached thereto.

An installation for fitting out flexible films generally contains the following parts (see figure 1):

- a table 1 on which the flexible film 3 is being positioned and held by a clamping mechanism 2.

- an installation ensuring the supply of contact elements coming from a feed coil, with the contacts 10 sitting on a supporting strip 9, and for the attachment, one by one, of these contacts 10 onto the aligned conductive tracks 11 , 12, 13 of the flexible film 3.

For every type of contact element a separate application device 15 is used. This device has the following tasks:

- the precise supply and positioning of the contact elements 10 so that for every mounting cycle a contact is placed in the application position;

- the cutting-off of the contact elements 10 from the supporting strip 9;

- the fitting of the contact element 10 onto one of the conductive tracks 11 , 12, 13 of the flexible film 3.

These devices are part of the known art and their functioning and parts are not part of the present invention.

Depending on the manufacturer and the type of contact, the feed direction of the contact element feed coils can differ. So a distinction must be made between devices that feed contact elements left to right and devices that feed contact elements right to left.

The method and installation that are the subject of the present invention allow for the supply of contact elements 10 in both directions.

The installation of the invention assumes that the flexible film 3 with conductive tracks 11 , 12, 13 is fastened onto a fixed table 1 and that the film 3 is consequently kept still during the complete cycle of the attachment of contacts onto the conductive tracks.

For fitting out conductive tracks that are aligned the one next to the other, the application device 15, responsible for the supply, positioning and attachment of the contact elements 10, has to be arranged so that it is movable in order to be able to place the contacts on the edge or end 4 of the flexible film 3, and to press the contact elements 10 through the conductive tracks 11 , 12, 13.

The resulting product is shown in figures 9 and 10, wherein the contacts 10 are furthermore equipped with a plastic housing in order to protect them and keep them in place (figure 11).

In order to maintain a stable position of the flexible film 3 during the fitting out process, it is held by means of a clamping mechanism 2. An end 4 of the film 3 hereby extends beyond the edge of the table 1 and the clamping mechanism 2.

In the area in which the free end 4 of the flexible film 3 extends, a positioning sled 5 is mounted which can move from left to right, or vice versa, along the end 4.

This positioning sled 5 is essentially equipped with the following parts:

- a stop 6 for the positioning of the free end 4 of the flexible film 3 which is subsequently clamped down on the table 1;

- a cutting mechanism 7 for cutting of the remaining supporting strip 9 of the contact elements 10;

- at least one optical detector 8 for measuring and determining the exact position of every conductive track 11 , 12, 13 of the flexible film 3.

- an application device 15 for the reception and supply, one by one, of the contact elements 10, which places one contact at a time in a transfer and application position, aligned with a conductive track of the flexible film 3. The application device 15 subsequently attaches the contact element 10 onto a conductive track by means of a press that also cuts the contact element 10 off of its supporting strip 9.

If so desired, a feed coil (not depicted) for the supply of the contact elements 10 which are connected to their supporting strip 9 can be mounted on or next to the sled 5, to the right hand side or the left hand side of the application device depending on the feed direction of the contacts towards the flexible film.

The method according to the invention comprises the following respective steps, each time with reference to:

- figure 2: the positioning sled 5 moves crosswise along the fixed table 1 until the stop 6 reaches the aligned position for insertion of the flexible film 3;

- figure 3: the flexible film 3 is advanced until its end 4 touches the stop 6; the clamping mechanism 2 of the table 1 is activated

at that time, ensuring that the flexible film 3 remains clamped down on the table 1 as the stop 6 is backed away;

- figure 4: the positioning sled 5 starts to move at that point. It moves along the full width of the free end 4 of the flexible film 3 during which operation the optical detector 8 moves over the conductive tracks 11 , 12, 13 that are aligned one next to the other. This way, the distances and positions of the tracks are measured precisely and saved in a computer file. In the case of special applications, such as miniature contacts, which require even more precise measurements, the sled can pass over the film a second time so that the optical detector 8 can also carry out the measurement in the opposite direction.

- figure 5: next the positioning sled 5 returns to the point where the application device 15 is aligned with the first conductive track

11 that needs to be fitted out with a contact element 10. The press of the application device 15 is then activated and a contact element 10 is cut off of its support strip 9 and transferred onto the first conductive track 11 of the flexible film 3;

- figure 6: subsequently the positioning sled 5 moves further until the application device is aligned with the second conductive track 12 that needs to be fitted out; In the mean time a new contact element 10 from the feed coil is received in the application device 15 and the press is activated again to attach a new contact element 10 onto the corresponding conductive track 12;

- figure 7: this cycle repeats itself for every conductive track on the flexible film that has been detected and measured by the optical

detector 8, until the last conductive track 13 has been fitted out with a contact element 10;

- figure 8: once the last conductive track 13 has been fitted out, the clamping mechanism 2 of the table 1 can be opened, and the flexible film 3 that is now equipped with contact elements 10 can subsequently be removed. The cutting mechanism 7 is now able to also cut off the free end of the supporting strip 9, off of which the contact elements 10 have been cut.

The optical detectors 8 are able to recognise the number of tracks on the flexible film and to measure the distance between the tracks or cables 11 , 12, 13. As a consequence, the installation can adapt its outfitter program by itself according to the type of flexible film it is presented with.

The whole of the method according to the invention is controlled by a computer program that allows for a selective outfitter pattern to be programmed. As a result it is possible to only place contacts onto tracks or cables for which it is necessary.

When two optical detectors 8 are installed, to the left and to the right of the stop 6 of the positioning sled 5, it will also be possible to execute the outfitter process without limitations from left to right or vice versa. The position of the feed coil with the contacts will of course need to be changed accordingly.

The method according to the invention has been described above based on one specific embodiment of a flexible film with three conductive tracks. It speaks for itself that other applications with more

conductive tracks or flat cables with more tracks are possible without departing from the scope of the invention.

Legend:

1 table

2 clamping mechanism

3 flexible film

4 flexible film end

5 positioning sled

6 stop

7 cutting mechanism

8 optical detector

9 supporting strip with contact elements

10 contact elements

11 , 12, 13 conductive tracks of the flexible film

15 application device