DE10125656A1 - strain relief - Google Patents

Abstract

A strain relief device for a flexible flat conductor, which has a carrier film and a given distribution of conductor tracks therein, in particular FPC and / or FFC flat conductors, has a first holding element and a second holding element, which lie between an open position for inserting the flat conductor and a holding position are movable and can be locked against one another in the holding position, a section of the flexible flat conductor being enclosable between the two holding elements.

Description

The present invention relates to a strain relief device for fle xible flat conductor.

There are usually strain relief devices in connectors provided that serve one with contact elements in the plug connector connected conductor to the housing of the connector attach so that there is a pull on the conductor from the housing of the connector and thereby a mechanical Bela the contact elements with possible loss of contact is avoided. According to the state of the art, strain relief takes place at the plug connector for flexible flat conductors in that Lö in the flexible flat conductor cher are punched through the corresponding tenon one with the fle xiblen flat conductor connected connector so that the flexible flat conductors exerted tensile forces over the edges of the punched holes be transferred to the pin in the connector housing.

However, this type of strain relief has the disadvantage that in one too additional work step corresponding holes in the flexible flat conductor to be punched.

In addition, there is a risk that the flexi ble flat conductor through the pins reaching into its holes the train  relief device or the connector torn and thus is damaged so that it must be replaced as a whole.

The disadvantages mentioned exist for all types of flexible flat conductors, especially for FPC flat conductors (flexible printed circuits) or FFC Flat conductor (flexible flat circuits).

In addition, it often makes sense to use strain relief devices depending on the connector to be used for tensile loads at lan against ladders. When using the described strain relief according to the prior art, the same disadvantages also occur here.

It is an object of the present invention to provide a strain relief direction for a flexible flat conductor, in particular also an FPC or FFC flat conductor to provide, when using a Zu strain relief of the flat conductor is achieved without additional work steps and the risk of tearing under high tensile loads is greatly reduced becomes.

The problem is solved by a strain relief device with the Features of claim 1.

A strain relief device according to the invention is for strain relief a given flexible flat conductor provided therein, the a carrier film and therein a given distribution of conductor tracks has. The flexible flat conductor can in particular be FPC and / or FFC flat conductors, which are un  decide that the thickness of the conductor tracks is essential for FPC flat conductors is lower than that of FFC flat conductors.

The strain relief device has a first holding element and second holding element, which for fastening a flat conductor between an open position for inserting the flat conductor and a holding position tion are movable and lockable against each other in the holding position, with a section of the flexible flat conductor between the two hal Teelemente is included. The holding elements can be in the open position may already be connected to each other or as two ge separate elements to be joined. Furthermore, for Locking appropriate devices, for example snap elements te, be provided, but not necessary on the holding elements themselves must be attached.

For strain relief, a projection and are on the first holding element a corresponding depression on the second holding element formed that when including the flexible flat conductor between the first and the second holding element and when the same moves into the holding po sition and mutual locking an area of the carrier film that no Has conductor tracks or only marginal areas of conductor tracks for Gentlast pressable from the protrusion into the recess and at the other Edge can be clamped. The holding elements are at or after Ver binding with the flexible flat conductor to exercise the necessary Clamping force locked against each other or connected to each other, for what Devices corresponding to the holding elements for locking or Connection can be provided. Because jamming in conductor track free areas or only marginal areas of conductor tracks  As a rule, the advantage does not extend across the entire width of the flexi blen flat conductor extend.

The projection on the first holding element and the corresponding one Depth on the second holding element depending on the Thickness of the carrier film of the flexible flat conductor must be dimensioned such that a corresponding clamping effect occurs at the edge. As a result of that possibly only edge areas of conductor tracks at the edge of the recess tion and these are usually from a relative position easily deformable metal such. B. copper, plays for the Clamping effect essentially only the thickness of the carrier film is essential Liche role, while the thickness of the conductor tracks is irrelevant.

By pinching the edge of the recess is ver equally small clamping area a high clamping pressure and thus one good strain relief, which also depends on the thickness of the ladder is largely independent. The invention is therefore suitable Strain relief devices especially for flexible flat conductors, the carrier foils of the same thickness but different conductor tracks Have thickness, especially for FPC and FFC flat conductors.

An additional contribution to strain relief can be the friction between the protrusion and the carrier film lying against it.

Because the strain relief alone by moving the first and the second Holding element with inserted flat conductor in the holding position and lock tion or joining is to train the Zugent  no additional work steps necessary, so that a very simple but reliable assembly is possible.

In addition, there is a risk of tearing under high tensile loads greatly reduced because tensile forces over the entire edge of the depression which the film is pinched.

The strain relief devices according to the invention are beyond made of plastic, e.g. B. by injection molding, very simple and inexpensive produced.

Further developments and preferred embodiments of the invention are in the description, the drawing and the dependent claims records.

Preferably, the projection and the recess are formed so that the Carrier film of the flexible flat conductor when it is clamped by the Edge of the recess is scored. The notch is created here by plastic deformation of the carrier foil of the flat conductor, which is usual Lich made of plastic or plastic laminates containing z. B. polyester or polyimides. By engaging the edge of the recess the strain relief of the invention Strain relief device absorb particularly high tensile forces.

The edge of the recess is be for a particularly good clamping effect preferably edge-shaped, the angle, that is enclosed by the surfaces forming the edge, about 90 ° is. Due to the edge-shaped design of the edge, the on  clamp over a comparatively small area, which means that not only the particularly good clamping effect is effected, but also the training a notch-like deformation in the carrier film is favored. In addition, there is a particularly effective form fit between the edged edge and the notch-like shape tion of the carrier film.

However, the projection and the recess should preferably be designed in this way be that when the flexible flat conductor is pinched, its carrier film only is scored and / or stretched, the stretch being egg ne act at least partially irreversible deformation of the carrier film can. However, the projection and the recess should preferably not be so be designed such that when the flat conductor is pinched, holes or cracks arise in the carrier film what z. B. with too narrow a gap between Lead out and edge of the recess or one in a tip the lead could occur. This will result in tensile loads less easily damage in the carrier film.

The projection is preferably dome-shaped, so that a loading Damage to the carrier foil of the flexible flat conductor is largely avoided is closed. With such a shape, the carrier film can be one inserted flexible flat conductor also over a large area on the front jump, which makes an additional contribution to strain relief due to the friction between the projection and the adjacent carrier film is enough.

Furthermore, the projection can preferably be in the form of a truncated cone be formed, with particular preference the truncated cone on its  narrow, free end has strongly rounded edges. Through the Tapering the truncated cone becomes a particularly good clamping effect achieved at the edge of the recess, even if the thickness of the carrier film is around their mean fluctuates more.

Are preferred in the direction of an expected train, i. H. usually in the direction of the longitudinal extension of the flat conductor, in each case at least three projections and three corresponding depressions are provided. there it is not necessary for all the projections to be formed on the first holding element, rather, individual projections can also be on the second holding element and the corresponding depressions in the first holding element be educated. As a result, the strain relief by the invention sse strain relief device absorb higher tensile forces because the forces be distributed over three marginal areas. In addition, the pre jumps also absorb torques, so that not too wide Flat conductors also secure against twisting the flat conductor in the Strain relief device is achieved.

Furthermore, one is expected to be essentially transverse to the direction the train preferably has at least two projections and corresponding ones Provided recesses in the holding elements, again here not all protrusions in the first holding element and all depressions in the second holding element must be arranged. By this arrangement the protrusions and recesses will rotate a flexible one Flat conductor in the strain relief device even when the width of the Avoided flat conductor.  

Since the strain relief in a strain relief according to the invention Direction takes place over areas of the carrier film that do not have a conductor track or only have edge areas of conductor tracks, the Ab is preferred stood between the first and the second holding element in the area of the Inclusion of the flexible flat conductor except on the projection larger than the thickness of the flexible flat conductor, i.e. including the carrier film of the conductor tracks. Such a strain relief device can therefore also the same for other flexible flat conductors with a carrier film Thickness, but different conductor thickness can be used.

Furthermore, a device for fastening the train outlet is preferred stungsvorrichtung, in particular on a body, provided. in this connection it can be an adhesive strip or parts of a Velcro fastener. However, fastening openings can also be made, for example, for rivet, Screw or snap fasteners may be provided. Furthermore can use snap elements on the strain relief device come. In particular detachable connections, for example screw, Velcro and some snap fastenings allow easy later disassembly of the flat conductor together with the strain relief.

Another object of the invention is a strain relief device with a flexible flat conductor held with it, in particular one FPC and / or FFC flat conductor, the strain relief device according to one of the above-mentioned embodiments or a combination one can be trained.  

Another object of the invention is a connector with an erin strain relief device according to the invention, in particular after the before preferred embodiments.

A connector according to the invention, which is a plug or a coupling can act, is for attachment to a given NEN flexible flat conductor provided.

The connection of contact elements provided in the connector ten with conductor tracks of the flexible flat conductor can by usual Ver drive like B. crimping process, pressure contacting or soldering drive done.

In the connector according to the invention, the train in particular Relief device connected to the housing, so that train Relief device and housing made of plastic, e.g. B. by spray cast, are very simple and inexpensive to manufacture.

In a preferred embodiment, the connector assigns two assemblable and interconnectable housing parts, between which a flat conductor can be included. One of the housing parts then has one of the holding elements, the locking of the holding elements against each other together with the connection of the housing parts he follows. Appropriate locking devices on the housing parts are in this context as part of the strain relief device to watch. By assembling and connecting the housing parts Inserting a flat conductor, which is simultaneously a movement of the holding parts in the holding position and a mutual locking effect can thus  in one step the connector housing and the Zu gene relief.

Preferred embodiments of the invention are set out below playfully described with reference to the drawings. Show it:

Fig. 1 is a schematic sectional view of a connector with flexible flat conductor according to a first preferred embodiment of the invention

Fig. 2 is a partial, schematic sectional view through the fastex binder with flexible flat conductor in Fig. 1 along the line AA and

Fig. 3 is a schematic perspective view of a Zugentla stungsvorrichtung with flexible flat conductor according to a second preferred embodiment of the invention.

Fig. 1 shows schematically a connector according to a preferred embodiment of the invention with a first housing part 10 and egg nem second housing part 12th The first housing part 10 and the second Ge housing part 12 are joined together and include an FPC flat conductor 14 between them. The housing parts in the area of the flat conductor are designed as holding elements 11 and 13 (indicated schematically in the drawing by dashed lines).

The FPC flat conductor 14 comprises a carrier film 16 with two copper conductors 18 a and 18 b enclosed therein. The carrier film 16 is only shown schematically here. It is constructed in a manner known per se from at least two plastic films laminated on top of one another, which enclose the copper conductor tracks 18 a and 18 b in a manner known per se. As can be seen in FIG. 1, the FPC flat conductor 14 therefore has a greater thickness in the regions which have the copper conductor tracks 18 a and 18 b than in the regions without conductor tracks. This creates in the area of the edge of the copper conductor tracks 18 a and 18 b a continuous transition from the large thickness in the area of the copper conductor track to the smaller thickness in the areas without a conductor track.

The integrated in the first housing part 10 on its underside Haltele element 11 has a recess 20 , the width of which corresponds precisely to the width of the FPC flat conductor 14 and which extends in the direction of the flat conductor, as can be seen in FIG. 2. In the middle of the recess 20 , three projections 22 a, 22 b and 22 c are formed, which are arranged in the direction of the conductor track 18 a and 18 b of the FPC flat conductor 14 between the copper conductor tracks 18 a and 18 b.

The holding element 13 integrated into the second housing part 12 also has a recess 24 which corresponds to the width and longitudinal extent of the recess 20 in the first housing part 10 . In the middle of this recess 24 three recesses are formed, which are arranged so that the projections 22 a, 22 b and 22 c when the first and the second housing part and thus the movement of the holding elements 11 and 13 into their holding position in this Deepening can intervene. In Fig. 1 only the corresponding recess 26 in the projection 22 a is visible. The edges of the depression are formed from edges, the two surfaces forming the edges enclosing an angle of 90 °. The recess is also so deep that when the first housing part 10 and the second housing part 12 are joined , that is to say when the holding elements 11 and 13 are in their holding position, the projections 22 a, 22 b and 22 c with the carrier film 16 arranged underneath do not touch the bottom touch the recess.

The projections 22 a, 22 b and 22 c and the corresponding depressions are shaped so that the FPC flat conductor 14 is clamped between the projection and the edges. As can be seen in FIG. 1 using the example of the recess 26 , the edge 28 notches the carrier film 16, as a result of which there is an additional positive fit between the edge and the carrier film 16 , which allows the holding elements 11 and 13 and thus the Connectors higher tensile forces can be absorbed. The projections 22 a, 22 b and 22 c have, as can be seen in FIG. 2, a circular cross section and are domed in the direction of the second housing part. In this way, on the one hand it is achieved that when the FPC flat conductor 14 is clamped in, the carrier film 16 is not punctured or torn through. On the other hand, the carrier film 16 lies flat on the projections 22 a, 22 b and 22 c, so that the friction between the corresponding areas of the projections 22 a, 22 b and 22 c and the carrier film 16 creates an additional strain-relieving effect.

As can be seen in Fig. 1, the FPC flat conductor 14 is only in an area that has no copper conductor tracks, pressed by the projections 22 a, 22 b and 22 c into the corresponding depressions and clamped at the edges thereof. The other areas of the FPC flat conductor 14 , in particular also the areas with the copper conductor tracks 18 a and 18 b, lie loosely in the space formed by the recesses 20 and 24 . Other flexible flat conductors, e.g. B. FFC flat conductors with the same thickness of the carrier foil but greater thickness of the copper conductor tracks can be used with the same connector, since the space formed by the recess 20 and 24 in the area of the holding elements 11 and 13 of the strain relief device has enough space also for the areas of an FFC - Flat conductor with thicker copper conductor tracks and on the other hand the clamping effect and thus strain relief is only achieved in areas of the carrier film without conductor tracks.

The housing parts 10 and 12 with the integrated holding elements 11 and 13 can be produced inexpensively by injection molding from plastic. They do not have to be designed as a solid body, as in this exemplary embodiment, but can also contain cavities, provided sufficient stability is ensured.

For assembly, the FPC flat conductor 14 is first inserted into the recess 24 in the second lower housing part 12 . Then the first Ge housing part is positioned over the second housing part, the two housing parts 10 and 12 are pressed together and connected to each other by a device not shown in the figures. By squeezing the carrier film 16 in the region of the projections 22 a, 22 b and 22 c, on the one hand, is somewhat stretched, which is not shown in the schematic representations in FIGS. 1 and 2, and on the other hand at the edges of the depressions a carrier film 16 is clamped to form a notch. The forces necessary for clamping are absorbed by the device for connecting and locking the two housing parts, not shown in the figures. The partially irreversible expansion leads to the formation of cup-shaped bulges in the carrier film in the region of the projection.

Fig. 3 shows a strain relief device according to a second preferred embodiment with a first holding element 30 and a second holding element 32 in an open position with an inserted FPC flat conductor 34 with conductor tracks 38 a and 38 b.

The strain relief device is formed in one piece from a sufficiently rigid plastic, the holding elements 30 and 32 being connected to one another on the first narrow side of the FPC flat conductor in the open position. The holding elements are formed in the areas facing the FPC flat conductor as are the holding elements 11 and 13 in the first exemplary embodiment.

In order to lock the retaining members 30 and 32 in the stop position of the first holding member 30 are provided at the end face 40 of a ridge 42 and on the second narrow side of the second holding member 32 on the end face 44 of a resilient strap 46 on the second narrow side above the web 42 snaps when the second holding member 32 is pressed against the first Hal teelement 34 .

To attach the strain relief device a Durchgangsöff opening 48 is provided, which allows attachment, for example, to a body part by means of screws or rivets.

LIST OF REFERENCE NUMBERS

10

first housing part

11

first holding element

12

second housing part

13

second holding element

14

FPC flat conductor

16

support film

18

a,

18

b Copper conductor tracks

20

recess

22

a,

22

b

22

c lead

24

recess

26

deepening

28

edge

30

first holding element

32

second holding element

34

FPC flat conductor

36

support film

38

a,

38

b Copper conductor tracks

40

face

42

web

44

face

46

hanger

48

Through opening

Claims (14)

1. Strain relief device for a flexible flat conductor ( 14 ; 34 ) having a carrier film ( 16 ; 36 ) and given distribution of conductor tracks ( 18 a, 18 b; 38 a, 38 b) therein, in particular FPC and / or FFC Flat conductor, with a first holding element ( 11 ; 30 ) and a second holding element ( 13 ; 32 ), which can be moved between an open position for inserting the flat conductor and a holding position and can be locked against one another in the holding position, wherein a section of the flexible flat conductor ( 14 ; 34 ) can be enclosed between the two holding elements, and in the case of which on the first holding element ( 11 ; 30 ) a projection ( 22 a, 22 b, 22 c) and on the second holding element ( 13 ; 32 ) a correspondingly corresponding depression ( 26 ) are designed such that when the flexible flat conductor ( 14 ; 34 ) is enclosed between the first and the second holding element ( 11 , 13 ; 30 , 32 ) and when the same moves into the holding position and mutual locking Area of the carrier foil ( 16 ; 36 ), which has no conductor tracks or only edge regions of conductor tracks ( 18 a, 18 b; 38 a, 38 b), can be pressed from the projection ( 22 ) into the recess ( 26 ) for strain relief and can be clamped to the edge ( 28 ) thereof , 2. Strain relief device according to claim 1, characterized in that the projection ( 22 ) and recess ( 26 ) are formed such that when the flexible flat conductor ( 14 ; 34 ) is clamped in, the carrier film ( 16 ; 36 ) of the flexible flat conductor through the edge ( 28 ) the recess ( 26 ) is notched. 3. Strain relief device according to claim 1 or 2, characterized in that the edge ( 28 ) of the recess ( 26 ) is edge-shaped. 4. Strain relief device according to one of the preceding claims, characterized in that
that the projection ( 22 ) and the recess ( 26 ) are formed
that when the flexible flat conductor ( 14 ; 34 ) is jammed, its carrier foil ( 16 ; 36 ) is only notched and / or stretched, but holes or cracks do not occur in the carrier foil. 5. Strain relief device according to one of the preceding claims, characterized in that the projection ( 22 ) is dome-shaped. 6. Strain relief device according to one of claims 1 to 4, characterized in that the projection ( 22 ) has the shape of a truncated cone. 7. Strain relief device according to one of the preceding claims, characterized in that at least three projections ( 22 a, 22 b, 22 c) and three corresponding depressions ( 26 ) are provided in the direction of an expected train. 8. Strain relief device according to one of the preceding claims, characterized in that at least two jumps ( 22 a, 22 b, 22 c) and corresponding recesses ( 26 ) in the first and the second holding element ( 11 , 13 ; 30 , 32 ) are provided. 9. Strain relief device according to one of the preceding claims, characterized in that the distance between the first and the second holding element ( 11 , 13 ; 30 , 32 ) in the region ( 20 , 24 ) for receiving the flexible flat conductor ( 14 ; 34 ) except on the projection ( 22 a, 22 b, 22 c) is greater than the thickness of the carrier film ( 16 ; 36 ) including the conductor tracks ( 18 a, 18 b; 38 a, 38 b). 10. Strain relief device according to one of the preceding claims, characterized in that a device ( 48 ) for fastening the Zugentlastungsvor direction, in particular on a body, is provided. 11. Strain relief device according to one of the preceding claims with a flexible flat conductor ( 14 ; 34 ) held thereby, in particular an FPC or FFC flat conductor 12. Strain relief device according to claim 11, characterized in
that the flexible flat conductor ( 14 ; 34 ) has a carrier film ( 16 ; 36 ) and a given distribution of conductor tracks ( 18 a, 18 b; 38 a, 38 b) therein,
that the first holding element ( 11 ; 30 ) and the second holding element ( 13 ; 32 ) are in the holding position and are locked against one another, a section of the flexible flat conductor ( 14 ; 34 ) being enclosed between the two holding elements, and
that the flexible flat conductor ( 14 ; 34 ) enclosed between the first and second holding element in the holding position ( 11 , 13 ; 30 , 32 ) in an area which has no conductor tracks or only edge areas of conductor tracks ( 18 a, 18 b; 38 a, 38 b), is pressed for strain relief from the projection ( 22 ) into the recess ( 26 ) and clamped to the edge ( 28 ) thereof. 13. Connector with a strain relief device after a of claims 1 to 12. 14. Connector according to claim 13, characterized in
that the plug connector has two housing parts ( 10 , 12 ) which can be joined together and connected to one another, between which a flat conductor ( 14 ) can be enclosed and each of which has one of the holding elements ( 11 , 13 ), and
that the locking of the holding elements ( 11 , 13 ) against each other takes place together with the connection of the housing parts ( 10 , 12 ).