Technical Field The invention relates to a locking device for a connector for cooperation with a recess of a member with which the connector is to be connected, said locking device being made of a spring elastic material and comprising two shanks which are movable towards and away from each other, at least one of the shanks at the en opposite the connector, on its side facing away from the other shank ex¬ hibiting a protruding hooking, means having an insert sur¬ face and a locking surface, said surfaces being arranged to cooperate with insert surfaces and locking surfaces within the recess.

State of the Art

The above referenced locking devices are used for different types of electrical connectors having spring loaded connector members, e.g. for mobile telephone equip- ments. The locking device should require small connecting and disconnecting force in order for such connectors to be quick and easy to connect and disconnect. The connectors are often accessible on the outside of the apparatus, and must on the other hand therefore also demand sufficiently large outer disconnecting force in order to prevent un¬ intentional disconnection due to mechanical influence be¬ cause of bumps and strokes. Furthermore, it is an require¬ ment that the connector is locked in connected position and is not influenced by the operating conditions. In mobile equipment connectors must not be influenced by the vibra¬ tions which might appear during the severest possible operating conditions under which the apparatus is intended to be operate .

EP-A-0 622 869 discloses a connector comprising an electrical female connector, which is mounted within a car body, and a male connector. Both connectors comprise

tubular house portions surrounding a number of terminals. Within the female connector is provided a hole member having a deep hole to receive a spring plate provided within the male connector, said spring plate having an outer shape corresponding to the shape of the deep hole within the female connector. The spring plate comprises two shanks each being fitted within the male connector. From the fittings the shanks are essentially parallel and on the middle the spring plate has a constricted portion and sub- sequently the shanks are again directed towards each other meeting in a front end having the shape of a rhomb. This connection between the shanks has the function of a hinge to support the compression of the shanks when the spring plate is inserted into the hole. The purpose of the connec- tor is to achieve a solid connection between the female and male connector in order to maintain electrical contact so that states of incomplete contact are avoided. According to EP-A-0 622 869 this is achieved by the spring plate which in order to obtain electrical contact must pass a con- stricted portion within the hole which corresponds to the constriction of the spring plate, the spring plate sub¬ sequently automatically being brought into place. If the spring plate on the other hand is not inserted sufficiently far it is pushed out from the hole and electrical contact is interrupted. Disconnection of the connector must be accomplished by traction force only.

As a result of a continuing effort for miniaturiza¬ tion and increasing number of force loaded connector members within each connector, e.g. for parallel trans- mission of data, higher demands are placed on these connectors, and therefore the known constructions cannot be miniaturized while maintaining the desired characteristics despite better materials. It is further a desire that the connector is easy to disconnect and has such a construction

that it can withstand a certain torque in order to further facilitate disconnection. The Invention

The purpose of the present invention is to further develop a locking device for a connector in view of the de¬ scribed problems and requirements, thereby considerably re¬ ducing the size of the connector without loosing the spring characteristics, and handleability or function safety. Above all the invention is aiming at achieving a locking device for a connector which easily can be connected by the locking device functioning as a guide for connection and is easy to disconnect by pulling force and/or level action, at the same time not being influenced by the operating con¬ ditions in connected position. This purpose is achieved by a locking device for a connector cooperating with a recess of a member, to which the connector is to be connected. The locking device is made of spring elastic material and comprises two shanks which are movable towards and away from each other, at least one of the shanks having a pro- truding hooking means. The shanks are tapering in a direc¬ tion towards the end opposite the connector and pass over into resilient , which have substantially even thickness, have thinner walls than the shanks and project towards each other, said resilient portions being connected by a con- necting portion. At the ends facing the connector the shanks form a functionally common base portion.

Due to the resilient portions and the connecting portion having a substantially thinner construction than the resilient shanks a large part of the spring function can be transferred from the shanks to the much more efficient resilient portions adjacent to the hooking means. Short Description of the Drawings The invention will be described further below reference being made to the accompanying drawings, in which

Fig. 1 is a perspective view of a locking device for a connector,

Figs. 2A-C are side elevations of a locking device according to Fig. 1 in different positions during a connec- tion procedure,

Fig. 3 is a perspective view of a two pole electrical connector with a locking device,

Figs. 4A and B are side elevations partly in cross section of a mobile telephone fixed at two locations of connection within a holder for the telephone,

Fig. 5 is an end view of a mobile telephone together with side elevations of different types of accompanying connectors provided with locking devices according to the invention, Fig. 6 is a perspective view of an alternative embodiment of a locking device,

Fig. 7 is a perspective view of another alternatively modified locking device, and

Fig. 8 is a perspective view of a further alter- natively modified locking device.

Detailed Description of the Invention

A locking device 10 in Fig. 1 for an electrical con¬ nector comprises two shanks 11, 12 which are joined at their the rear ends by a common base portion 13 intended to be fixed to a connector. For reasons of manufacturing the base portion 13 can be divided, the parts of the base portion then having such shape that they functionally work as one part only; see Fig. 7. The shanks 11, 12 are pivotally movable towards and away from each other, nd in order to permit a sufficiently large compression or ...αgular motion of the shanks 11, 12 in the direction towards each other the shanks are tapered in a direction away from the base portion and the plane inner surfaces 14, 15 of the shanks form an angle with each other when the locking device is in an unloaded state.

At the end of the locking device 10 opposite the base portion 13 the two shanks 11, 12 passes over into resilient portions 18' which have a substantially even thickness, have thinner walls than the shanks, extend towards each other, and are connected by a connecting portion 18. The shape of the portions 18' together with the connecting portion 18 can be an arch, i.e. almost semicircular, have a softer elliptic form or a more planar connecting portion 18 with larger radius and portions 18' passing over into the shanks 11, 12 with smaller radius, forming a blunter shape. Also other shapes of the portions 18 and 18' are possible, as will be described further below. The resilient portions 18' connect to the shanks 11, 12 under the formation of the hooking means 19, 20 each comprising a locking surface 21, 22 facing the base portion 13, said locking surface being formed by the end of the resilient portion 18 at its con¬ nection to the shank 11, 12, and an insertion surface 23, 24 in the direction of insert, according to the arrow shown in Fig. 1. Due to the resilient portions 18' and the con- necting portion 18 being shaped substantially thinner than the resilient shanks 11, 12, a large part of the resiliency can be moved from the shanks 11, 12 to the considerably more efficient portions 18 and 18' adjacent to the hooking means 19, 20. The size of the locking device 10, and there- fore consumption of material, can be decreased considerably without the characteristics of resiliency being deteriorated. The length of the part of the locking device 10 being exposed outside a connector is between 3 and 25 mm, preferably <10 mm. The locking device 10 is intended to be the male portion in a substantially torsionally rigid plug contact of a connector. In Fig. 2 is shown the female portion of the connector, which is a recess 25 having a rectangular aperture with planar, substantially parallel insert surfaces or side walls 26, 27, and internal angular locking

surfaces 28, 29. The insert surfaces 23, 24 directed in the direction of insertion facilitate the insertion of the locking device 10 into the recess 25. Thus, the portions 18 and 18' make the locking device 10 selfcentering towards the recess 25 and therefore admits a larger degree of deviation at the insertion of the locking device 10 into the recess 25.

An angle α between each locking surface 21, 22 of the locking device 10 and a plane perpendicular to the longi- tudmal axis of the locking device 10 may be varied in dependence of the desired locking force A small angle α provides a large locking force of the locking device 10 while a large angle a provides a small locking force. An angle α of approximately 30° is preferred but larger or smaller angles are also possible. For example, an angle α<0° implies that the hooking means 19, 20 provide an irreversible locking by being in the form of a barb, and α>90° that the ends of the arch 18 pass over directly to the shanks 11, 12 without forming any hooking means 19, 20, see Fig. 6 The angle α may of course be different at the respective hooking means The locking surfaces 28, 29 within the recess 25 having an angle β between each locking surface 28 or 29 and a plane perpendicular to the direction of insertion within the recess do not necessarily have angles β of mutually the same size.

Fig. 3 shows that the locking device 10 provided at a connector 30 at the portions 18 and 18' can have an asymmetrical outer shape or so called key shape in order to prevent insertion m the wrong position into the recess 25 which is correspondingly asymmetrically profiled, see Fig 5. The asymmetrical profiling is achieved e.g. by a sub ^¬ stantially right angle recess 31 m the locking device 10, said recess 31 extending at least over the part of the locking device being exposed outside the connector 30 In

the same manner a key shape is formed in the recess 25 by e.g a cut m a corner 32, see Fig. 5

The connecting portion 18 is shown m Figs. 1-6 with even thickness but may according to Fig. 7 along the longitudinal axis of the locking device have a tongue 33 directed towards the base portion 13. When the recess 31 also extends over the tongue 33 a more efficient key shape can be achieved The tongue 33 may also be shaped according to Fig 8 where the tongue 33 is not solid but is formed m that the connecting portion 18, which m this case has a thickness substantially corresponding to the thickness of the portions 18', has a curved, droplike form Due to the tongue 33 a more resistant locking device can be achieved and the embodiment according to Fig 8 prevents e.g. a collapse of the connecting portion if the locking device is inserted with an angle into the recess 31 as the connecting portion 18 is elongated and the tensions withm the material at external mechanical stress then are decreased The connector 30 comprising a locking device accord- mg to the invention may well be used withm areas where locking with small dimensions and large locking force is required at the same time as the connector should be easy to disconnect by lever action.

Fig. 4A shows a connector 30 fixed in a telephone holder 34 in a vehicle having a locking device A telephone 35 can then be disconnected and detached from the holder 34 by lever action the direction of the arrow around a point of action 36 between the telephone 35 and the fixed holder 34. As described above the hooking means 19, 20 of the locking device 10, see Fig. 2, may have angles of mutually different sizes, and especially when the locking device 10 is disconnected by means of lever action it may be advantageous if the hooking means 19 or 20 closest to the lever hinge has a smaller angle α than the angle α for the hooking means 19 or 20 situated farthest from the lever

hinge, so that the locking device 10 then requires a smaller disconnecting force.

In cases where a large number of connections and dis¬ connections are required without the locking character- istics being deteriorated, a locking device 10 with a small locking force may be used in a connector 30, see Fig. 4B. This locking device 10 which may be provided in a connector 30 that may be connected at the back of the telephone 35 and is attached to the holder 34 e.g. for an external antenna, is disconnected by mere pulling force without lever action. The locking device 10 may also be used at different types of suspension applications.

By the combined arrangement in Fig. 4A and 4B the telephone 35 may be securely connected mechanically and electrically at two different locations in the holder 34 with substantially only one operation. A separate lock does not have to be detached at the disconnection, which is accomplished by the user simply grasping the telephone 35 at the top and pulling it towards himself, the locking device 10, in Fig. 4B, first being detached by pulling force, and the locking device 10, in Fig. 4A, then being detached by lever action.

If the connector 30 is not provided in a fixed holder 32 but instead is a free connector, such as a full function connector 30, shown in Fig. 5 intended for data trans¬ mission, an audio connector 30 or a battery charger contact 30, it may of course be detached in a corresponding way by lever action from the point of action of the locking device 10 in the recess 25 of the telephone 35. The locking device is suitably made of a rigid or semi-rigid elastical polymer material, e.g. acetal amide such as nylon etc., but also metal can be used. Important features of the material are among other things high tough ^¬ ness and rigidity, good abrasive and friction character- istics, temperature resistance and high dimensional

stability. The type of material used depends on the field of application, outer conditions, environmental require¬ ments etc.