BACKGROUND OF THE INVENTION

The present invention relates to the improvement of a waterproof electrical connector and more particularly to the improvement of a seal ring employed in a waterproof electrical connector.

In many of the electrical connectors, a male connector housing and a female connector housing are engaged with each other for electrical connection through terminal members installed therein. If such connectors are to be installed at a place where they are subject to rain water, waterproof electrical connectors are used to prevent short circuiting.

One example of such conventional waterproof electrical connectors is shown in FIG. 1, in which a male connector housing 1 is to be engaged with a female connector housing 2. Around the periphery 1a of said male connector housing 1, there is formed an annular enclosure 1b. Said annular enclosure 1b is formed by an annular wall 3 surrounding said outer periphery 1a and an end wall 4 extends radially to connect said annular wall 3 and said outer periphery 1a to define an annular cavity 6. On the other hand, the female connector housing 2 includes an outer periphery 2a and a sleeve 2b extending forwardly of said outer periphery 2a.

When a seal ring 7 of resilient material such as rubber is inserted in said cavity 6, said seal ring 7 fits against the annular enclosure to leave a space 6' inwardly thereof. At the same time, said seal ring is formed with an engaging protrusion 7a in an outer periphery thereof as shown in FIG. 2, said engaging protrusion 7a is squeezed into an engaging window 3a formed in the annular wall 3 of the male connector housing 1 for securing said seal ring 7 within said cavity 6.

FIG. 3a is a sectional view of the seal ring 7 taken along the line III--III of FIG. 2 to show a seal ring 7c which bulges around the inner periphery thereof which press contacts the sleeve 2b of the female connector housing 2. In the prior art as described in the foregoing, said seal ring 7 has a tendancy to turn over inside out at the time of engagement or disengagement of both housings as shown in FIG. 3b. In this way, the positioning of the seal ring 7 within the cavity will not be assured for making the connector waterproof. In order to overcome the shortcoming of the prior art waterproof connector, it is an object of the present invention to provide a seal ring which will not turn over even at the time of engagement or disengagement of the male and female connector housings.

SUMMARY OF THE INVENTION

Essentially, the above object is realized by providing a waterproof electrical connector comprising: a first connector housing having an annular enclosure formed around an outer periphery thereof, said annular enclosure including an annular wall surrounding said outer periphery of the first connector housing and an end wall extending radially to connect said annular wall and said outer periphery to define a cavity; a seal ring inserted in said cavity, and having a first section of smaller wall thickness to leave a space forwardly opening and a second section of larger wall thickness extending rearwardly of said first section to resiliently press fit said annular enclosure, said end wall and said outer periphery; and a second connector housing having a sleeve formed forwardly of an outer periphery thereof and adapted to be inserted into said space.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the male and female connector housings engaged with each other in the prior art waterproof connector;

FIG. 2 is a perspective view of the seal ring used in the connector of FIG. 1;

FIG. 3a is a partially broken-away view of the seal ring in section along the line III--III of FIG. 2;

FIG. 3b is a similar view of the seal ring which shows a turned over state of the seal ring of FIG. 3a;

FIG. 4 is a longitudinal sectional view of one embodiment of the present invention;

FIG. 5 is a longitudinal sectional view of another embodiment of the present invention;

FIG. 6 is a perspective view of the seal ring used in the embodiments of FIG. 4 and FIG. 5;

FIG. 7 is a sectional view of the seal ring shown in FIG. 6 taken along the line VII--VII.

FIG. 8 is a longitudinal sectional view of a further embodiment of the present invention;

FIG. 9 is a perspective view of the seal ring used in the embodiment of FIG. 8; and

FIG. 10 is a sectional view of the seal ring shown in FIG. 9 taken along the line X--X.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 4, in which one embodiment of the present invention, the male and female connector housings 1 and 2 are engaged. Although not shown, the male connector housing 1 is accommodated with female terminal members and water seal plugs therein whereas the female connector housing is accomodated with male terminal members and water seal plugs. Basically, the structure of the waterproof connector of the invention is similar to that of the prior art connector. For example, there is formed an end wall 4 erecting from around the outer periphery 1a of the male connector housing 1 while an annular wall 3 is extending parallelly around the outer periphery 1a of the male connector housing 1. Said annular wall 3 and said outer periphery 1a is connected by the end wall 4 to define a cavity 6 therebetween.

Within said cavity 6 a seal ring 7 is inserted. As shown in FIG. 6, said seal ring 7 has a first section 7.sub.1 of smaller wall thickness to leave, when inserted in the cavity 6, a space 6' forwardly opening and a second section 7.sub.2 of larger wall thickness extending rearwardly of said first section to resiliently press fit said annular enclosure 3, said end wall 4 and said outer periphery 1a. It is particularly important that said second section 7.sub.2 has a sufficient size to reach the outer periphery 1a of the first connector housing. Again, like a prior art connector, said seal ring 7 is formed with a engaging protrusion 7a which is squeezed into a window 3a in the annular enclosure for positioning said seal ring 7 generally within said space 6.

In the embodiments of FIGS. 4 and 5, said second section 7 takes the form of inwardly extending rib 7b.

Said rib 7.sub.2 serves the purpose of preventing the seal ring 7 from turning over inside out as a result of torsion caused at the time of disengagement by a shearing force by means of the contact surfaces of the seal ring 7 and the annular wall 4. Therefore, the rib may be formed in the outside of the seal ring 7 or in both sides thereof instead of only in the inside thereof as shown in FIGS. 5 and 6. In case where a rib is formed in the outside of seal ring 7, such rib serves to act as an engaging protrusion 7a.

The rib 7b is formed between the tip of the sleeve 2b and the end wall 4. However, the rib 7b is not required to be compressed for performing sealing action, which is performed by the radial compression of the seal by means of the inner periphery of the annular enclosure and the outer periphery of the sleeve 2b.

With the seal ring within the cavity 6, both connector housings will be prevented by said rib 7b from sliding over each other in an engagement direction, male and female terminal members housed in the connector housings are prevented from being worn out through their sliding movements and the resultant poor contact is avoided.

However, if the rib is longitudinally too thick the tip of the sleeve 2b and end wall 4 must compress the rib requiring a large force at the time of engagement. In order to avoid it, a groove 4a continuous around the outer periphery of the male connectors formed in the end wall at an innermost end thereof where said end wall 4 contacts the rib 7b such that the compression force is released at the time of engagement. In other words, when the compression is exerted on the rib 7b, said rib is deformed in a curved line and received into said groove 4a, thus facilitating engagement with a reduced force.

Referring to FIGS. 8 through 10, a further embodiment is shown in which the basic structure is similar to those embodiment in the foregoing except that the sleeve 2b of the second connector housing 2 is adapted to come into sliding engagement with the interior of the annular wall 3 while the seal ring 7 is inserted within the cavity 6 for the first section 7.sub.1 thereof to contact the outer periphery 1a of the first connector housing 1.

Consequently, the second section 7.sub.2 is provided in the form of outwardly extending rib 7b as best shown in FIG. 9. Further, the seal positioning provided by the relationship of engaging window 3a and engaging protrusion 7a in the prior art and foregoing embodiments is accomplished by provision of a plurality of recesses 7d circularly formed in the inner side surface of the seal ring 7 and corresponding projections 1b formed in the outer periphery 1a of the male connector housing 1 to be received therein.

Throughout the embodiment, it will be understood that the seal ring 7 has a bulge 7c to secure the seal thereof against the sleeve. To make said bulge 7c work properly, the recesses 7d formed in the seal ring 7 is preferably formed in positions staggered from said bulge 7c.

As explained in the foregoing, the seal ring provided in the engaging portion the connector housings of the present invention is formed with a rib in the outer and/or inner periphery thereof while the end wall of one of the housings is formed with a groove at an innermost end thereof. As a result, the seal ring is resistant to the shearing force due to its larger wall thickness at the time of connector engagement and disengagement to keep from turning over inside out, thus preventing water leakage due to seal dislocation within the cavity. Moreover, the provision of the groove in the end wall has accomplished easy engagement of connector housings without use of large force.