Spring Locking Device for Connector

This invention relates to a spring locking device for a connector, which prevents connected male and female connector members of the connector from being disconnected as by external forces, and more particularly to a spring locking device for a connector, which prevents any disconnection of connected connector members of the connector and at the same time serves to reduce the number of parts of the connector.

For example, spring locking mechanisms as shown in FIGS. 1a and 1b have been widely used in order to prevent fitted connected male and female connector members from being disconnected by external tensile forces acting upon a connection cable and the like.

A locking member 1 of the spring locking mechanism as shown in FIG. 1 is made of a springy metal wire which is bent to have two support pins 1a, two legs 1b perpendicular to the support pins, and a rhombic latch portion 1c having a width wider than a distance between the two legs 1b. On the other hand, a mounting flange 2a of a metal shell 2 of a female member A is formed with bearings 2b which are formed by slitting and then raising parts of the flange 2a away therefrom by punching as shown in FIG. 1b. The locking members 1a are mounted to the female connector member A by inserting the support pines 1a into the bearings 2b.

Moreover, a mounting flange 3a of a metal shell 3 of a male connector member B is formed with leg guide slits 3b having a width narrower than the distance between the legs 1b and locking apertures 3c at inner ends of the leg guide slits 3b and continuous thereto. Diameters of the locking apertures 3c are larger than the width of the leg guide slits 3 but smaller than the width of the rhombic latch portion 1c.

When the female and male connector members have been fitted and connected, the locking member 1 are turned with the rhombic latch portions 1c against their spring forces so that the legs 1b are forced through the leg guide slits 3b and positioned in the locking apertures 3c. The legs 1b of the locking member 1 are once narrowed by the leg guide slits 3b and again permitted to expand in the locking apertures 3c by their spring forces, so that the locking members 1 are prevented from being removed through the leg guide slits 3b and further resist to any external pulling forces with the aid of the rhombic latch portions 1c wider than the locking apertures 3c. The connected female and male connector members are thus prevented from being disconnected by external forces.

With the spring locking mechanism of the prior art as above described, after the rhombic latch portions 1c of the locking members 1 have been pressed inwardly to narrow the distances between the legs 1b, the support pins 1a of the locking members 1 are positioned between the bearings 2b of the female connector member A and the rhombic latch portions 1c are then released. As a result, the legs 1b expand by their springy return forces to insert the support pins 1a into the bearings 2b.

In the arrangement of the locking mechanism of the prior art, the locking members 1 are likely to be removed from the connector because the support pins 2a are apt to be dislodged from the bearings owing to narrowed distances between the legs 1b and other reasons for example when the legs 1b are inserted in the leg guide slits 3b for locking.

In order to overcome this problem, in the prior art for example as shown in FIGS. 3a-3c a removal preventing projection 4 is provided between the two bearings 2b and legs 1b of locking members 1 are bent as shown at 1b in FIG. 4b which is a side view of the locking member 1 of FIG. 4a. Therefore, when the legs 1b are inserted in the leg guide slit 3b, the removal preventing projection 4 is positioned between the bottoms of the legs 1b to prevent any removal of the support pins 1a from the bearings 2b.

In such a solution, however, a metal plate 5 is separately needed which has bearings 2b and removal preventing projections 4 by punching and bending. The metal plate 5 is then fixed to the mounting flange 2a of the connector member by means of eyelets or the like as shown in FIG. 3a. As an alternative, an insulating block 6 of a connector member is formed integrally with removal preventing projections 4 so that when a mounting flange 2a is secured on the insulating block 6, the removal preventing projections 4 extend beyond the mounting flange 2a through apertures previously formed in the mounting flange 2a as shown in FIG. 3b or 3c.

Therefore, the number of parts constituting the connector is increased and dies for molding the insulating block 6 are complicated to increase manufacturing cost of the connector.

It is a primary object of the invention to provide an improved spring locking device for a connector, which eliminates all the disadvantages of the prior art and can prevent any unintentional removal of locking members from the connector in a reliable manner without using removal preventing projections 4 to reduce manufacturing costs of the connector.

In order to achieve the object, in a spring locking device for a connector including a female connector member and a male connector member, said spring locking device including two pairs of bearings arranged on both ends of a mounting flange of one connector member, respectively, each of the bearings having openings in directions substantially perpendicular to longitudinal directions of the one connector member and having a semicylindrical inner surface, and locking members made of a springy wire, each locking member having two legs spaced in parallel with each other and two support pins formed by bent outwardly relative to the legs and rotatably supported in said one pair of bearings, thereby locking the two connector members by turning the locking members into slits formed in the other connector member after the two connector members are connected, according to the invention each of the locking members comprises the legs having lower ends outwardly bent and the support pins continuous to the lower ends and having bent corners between the lower ends and the support pins, and said bent corners are positioned inside of the bearings and in contact with bottoms of the bearings and said support pins are in contact with semicircular edges of the bearings and extend therefrom out of the bearings on sides opposite to those of the legs when the locking members are mounted in the bearings.

With this arrangement, the spring locking device according to the invention can prevent the support pins of the locking members from removing from the bearings in a reliable manner by simply modification of the locking members without using removal preventing projections. Therefore, reduction in number of parts and simplification of dies for molding insulating housings can be accomplished, thereby lowering the manufacturing cost of connectors.

In a preferred embodiment of the invention, the mounting flange is provided with stopper members having heights from the mounting flange and facing to openings of the bearings in opposition to each other and positioned in the proximity of the openings.

In a further embodiment, the bearings are formed by slitting and then raising parts of the mounting flange, and edges of cut portions caused by raising the slit parts are the stopper members.

The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.

FIGS. 1a and 1b, 2a and 2b, 3a 3c and 4a and 4b are explanatory views of a locking device of the prior art;

FIGS. 5a-5d are explanatory views of one embodiment of a spring locking device for a connector according to the invention;

FIGS. 6a-6d are views illustrating examples of dimensions of the locking member and the bearing of the locking device according to the invention;

FIG. 7 is a view of a modification of the locking device according to the invention; and

FIG. 8 is an explanatory view for a relation between the locking member and the bearing of the device according to the invention.

According to the invention, locking members are particularly formed in construction to ensure the prevention of removal of the locking device for a connector.

Referring to FIGS. 5a, 5b and 5c, each of the locking members comprises legs 1b having lower ends 1b1 outwardly bent at an angle and support pins 1a continuous to the lower ends 1b1 and bent directing upwardly and outwardly. A bent corner 1b2 of each of the support pins 1a continuous to the lower end 1b1 of the leg 1b is positioned inside of the bearing 2b and in contact with a bottom of the bearing 2b. On the other hand, each of the support pins 1a extending from the bent corner 1b2 is in contact with a semicircular edge 2b2 of the bearing 2b and extends therefrom out of the bearing 2b on a side opposite to that of the leg 1b.

In this case, an angle of the support pin 1a extending outwardly and upwardly with a horizontal may be equal to or slightly larger than an angle .alpha. shown in FIG. 8 which is an angle of a diagonal (shown in a dot-and-dash line) of a rectangle of the bearing in section with a mounting flange 2a. It becomes from the reason that the bent corner 1b2 is positioned inside of the bearing 2b and 2b, while the support pin 1a is in contact with the semicircular edge of the bearing 2b and extends therefrom.

The lower end 1b1 of the leg 1b is bent outwardly at an angle such that insertion of the bent corner 1b2 into the bearing 2b is not obstructed by a semicircular edge on opposite side of the semicircular support pin 1a.

When the legs 1b expand outwardly, they abut against the edges of the bearings to prevent further outward expansion of the locking member. If the lower ends 1b1 are bent at a large angle so as to bring the lower ends 1b1 into parallel with the flange 2a, they do not serve to prevent such a further expansion of the locking member 1. Therefore, such a large angle of the lower ends of the legs is not preferable.

In a particular case, the locking member 1 may be constructed as follows. As shown in FIG. 5a, two legs 1b of a locking member 1 are bent outwardly, and support pins 1a are formed by bending it upwardly at an acute angle .theta. with the lower ends 1b1 of the legs 1b. Distances between two bearings 2b are so selected that the support pins 1a can be inserted into the bearings 2b by narrowing the distance between the legs 1b, thereby providing reaction spring forces to open the legs 1b outwardly.

The length and the bent angle of the support pins 1a, the length of the bearings 2b, the inner diameter of the bearing apertures 2b1 and the spring force of the wire of the locking members 1 are so selected that when the support pins 1a are inserted in the bearing apertures 2b1 as shown in FIG. 5d, the support pins 1a are urged downwardly by inner upper surfaces of the bearing apertures 2b 1 so as to be deformed to produce reaction spring forces, and that when the insertion of the support pins 1a has been completed, tip ends of the support pins 1a are pressed against pressing edges 2b2 by reaction spring forces while the tip ends of the support pins 1a extend out of the bearings 2b as shown in FIG. 5c.

In this case, moreover, as shown in FIG. 5c, the bent corner 1b2 between the support pin 1a and the leg 1b is firmly in contact with a surface of the insulating housing 6 by the reaction spring force of the locking member 1. The surface of the insulating housing 6 in question is exposed as a bottom of the bearing 2b by forming the bearing 2b by slitting the mounting flange 2a fixed to the insulating housing 6 and then raising the slit portion away from the mounting flange 2a. Moreover, when a force acts on the support pin 1a so as to remove it from the bearing 2b, a portion near to the bent corner 1b2 abuts against a edge 2a 2 portion 2a l as a stopper member facing in a direction opposite to the possible removing direction of the support pin 1a.

FIG. 7 illustrates one embodiment of the device according to the invention. A mounting flange 2a is provided with stopper members 2b2 having a height from the mounting flange 2a and facing to the openings of the bearings and in the proximity of the openings facing toward each other. The height of the stopper members 2b2 is sufficient to be of the order of one third of a diameter of the wire of the locking member 1. An attachment of the stopper members 2b2 is preferably effected by an adhesive or by spot welding.

With the spring locking device according to the invention constructed as above described, even if the distance between the two legs 1b of the locking member 1 is narrowed to cause the support pins 1a to remove from the bearings 2b in case for example that the legs 1b are forced into the leg guide slit 3b of a mating connector, the bent corner 1b2 or its near portion abuts against the stopper member 2a2 to resist the removing force acting upon the locking member 1 because the support pins 1a are sliding along and depressed by the semicircular edges 2b2 of the bearing 2b. Therefore, the removal of the support pins 1a from the bearings 2b is completely prevented without using the removal preventing projections 4 used in the prior art.

In the embodiment above described, the locking member includes bent portions 1b3 at which the legs 1b are bent forwardly as shown in FIG. 5b. Such bent portions 1b3 may be dispensed with because having no removal preventing projections 4 in the invention.

FIGS. 6a and 6b illustrate a locking member 1 and FIGS. 6c and 6d show bearings 2b of one example of the locking device according to the invention.

The bearing 2b had a bearing aperture 2b1 whose diameter was 1.2 mm and length was 2 mm. A mounting flange 2a for a shell had a thickness of 0.5; mm. The bearings 2b were arranged spaced apart 7.5 mm.

The locking member 1 was made of a stainless steel having a diameter of 0.9 mm and formed in a shape as shown under a completely relaxed condition in FIGS. 6a and 6b. When the locking member 1 was mounted condition between the bent corners 1b2 of the deformed locking member 1 became substantial equal to 7.5 mm which was the distance between the bearings 2b.

As can be seen from the above description, the spring locking device according to the invention can prevent the support pins of the locking members from removing from the bearings in a reliable manner by simply modification of the locking members without using removal preventing projections. Therefore, reduction in number of parts and simplification of dies for molding insulating housings can be accomplished, thereby lowering the manufacturing cost of connectors.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.