Three part electrical connector with preventation latching means

The invention prevents a sub-connector housing from being inadvertently separated from a frame. A frame 10 is installed in an attachment hole 2 of a panel 1. When a male sub-housing 20 is pushed from a posterior direction into a housing chamber 13 formed within the frame 10, a protruding member 44 of a locking arm 43 provided on an outer face of a posterior end of the sub-housing 20 latches resiliently against a stopping member 51 of a stopping plate 50 provided on an inner face of the housing chamber 13. A large hood member 33 of a corresponding female housing 30 is fitted with the sub-housing 20 from the anterior thereof, this large hood member 33 covering an outer circumference of a anterior end of the sub-housing 20. A recess 37 is formed at a tip of this large hood member 33. When the two housings 20 and 30 are correctly fitted together, a tip of the locking arm 43 fits into this recess 37. If the two housings 20 and 30 are correctly fitted together, the bending of the locking arm 43 is regulated and the locking arm 43 is maintained in a latched state with the stopping member 51.

TECHNICAL FIELD
 The present invention relates to an electrical connector in which a
 sub-connector housing is installed inside a frame.
 BACKGROUND TO THE INVENTION
 A split connector is occasionally used as a multiple connector in order to
 allow terminal fittings to be inserted correctly into corresponding
 cavities, or in order to allow conductivity to be tested conveniently,
 etc. This split connector has a configuration whereby a plurality of
 housing chambers are partitioned within a frame. Sub-connector housings
 distributed within cavities are inserted from the posterior into each
 housing chamber and are housed therein. These sub-connector housings fit,
 from anterior faces thereof, with a corresponding connector housing.
 A means to retain the sub-connector housing in a latched state within the
 housing chambers is described for example, in JP 10-229621. Outer faces of
 the sub-connector housings are provided with bendable locking arms, these
 engaging resiliently with stopping protrusions provided on inner faces of
 the housing chambers.
 However, the latching configuration of the conventional example has the
 following problem. If, for example, excessive force is used on the
 sub-connector housings to pull them in a posterior direction, the locking
 arms may bend excessively and the sub-connector housings may separate from
 the frame
 The present invention has taken the above problem into consideration, and
 aims to present a sub-connector housing which will not be separate
 inadvertently from the frame.
 SUMMARY OF THE INVENTION
 According to the invention there is provided an electrical connector
 comprising a frame, a sub-connector latchable in said frame on a latching
 axis, and a mating connector latchable with said sub-connector also on
 said latching axis, the sub-connector having a resilient latching arm
 protruding in the direction of said latching axis, and bendable
 transversely of said axis for engagement with a latch member of said frame
 characterised in that said mating connector includes a recess adapted to
 receive said latching arm in close fitting engagement on connection of
 said sub-connector and mating connector, thereby to prevent transverse
 bending of said latching arm.
 This arrangement ensures that the latching arm is immovable once the mating
 connector has been fitted to the sub-connector. Accordingly, resistance to
 a high separation force is increased.
 Preferably the tip of the latching arm engages in an external groove of a
 hood of the mating connector. Such a groove can be conveniently formed in
 a protruding flange of the hood, and does not penetrate the wall of the
 hood itself.
 The frame preferably includes a latching portion for the latching
 projection, this portion being defined in the preferred embodiment by wall
 members extending in the direction of said axis.
 A protrusion of said wall and a projection of said latch member may define
 the latch between said sub-connector and frame.

DESCRIPTION OF THE PREFERRED EMBODIMENT
 An embodiment of the present invention is described below with the aid of
 FIGS. 1 to 7.
 In the present embodiment as shown in FIG. 1, two (only one is shown) male
 sub-connector housings 20 are housed inside a frame 10, a corresponding
 female connector housing 30 being fitted individually with each
 sub-housing 20.
 The frame 10 is cylindrical and is stepped so that an anterior face (at the
 top in FIG. 1) thereof is larger. The frame 10 is inserted from an
 anterior direction into an attachment hole 2 of a panel 1 attached to a
 car body or the like. A stopping groove 11 formed on an outer
 circumference of an anterior edge of the frame 10 fits with a hole edge of
 the attachment hole 2, thereby attaching the frame 10.
 A partitioning wall 12 is formed at a posterior portion within the frame
 10, this partitioning wall 12 dividing the frame 10 into left and right
 housing chambers 13A, 13B.
 The sub-housing 20 shown in FIG. 2 is housed within the left housing
 chamber 13A, and has an approximately rectangular cross-sectional shape,
 the corners thereof being rounded. A plurality of cavities 21 formed in an
 aligned manner within a terminal housing member 22 form an upper and a
 lower row. A small hood member 23 is formed on an outer circumference of
 an anterior face of the terminal housing member 22. A male terminal
 fitting (not shown) is inserted from a posterior direction into each of
 the cavities 21. The male terminal fittings are housed in the small hood
 member 23 so that tabs belonging to the male terminal fittings protrude
 into the small hood member 23.
 Four ribs 24 protrude from an outer circumference of an anterior face of
 the small hood member 23. The ribs 24 protrude at locations close to
 diagonally opposing corners on an upper and a lower face of the small hood
 member 23, and from locations slightly below the centre of left and right
 side faces of the small hood member 23.
 The female housing 30 which fits with the sub-housing 20 is formed as shown
 in FIG. 3. The female housing 30 has a terminal housing member 32, and
 cavities 31 which are mutually aligned therein and which house female
 terminal fittings (not shown). A large hood member 33 is formed on an
 outer circumference of an anterior face of the terminal housing member 32,
 this large hood member 33 being capable of fitting around an outer
 circumference of the small hood member 23. Guiding grooves 34 are formed
 in an inner circumference of an anterior face of the large hood member 33.
 The guiding grooves 34 are capable of fitting with the respective ribs 24
 of the small hood member 23.
 Furthermore, a stopping arm 35 is provided on an upper face of the female
 housing 30. When the two housings 20 and 30 have been correctly fitted
 together, this stopping arm 35 engages resiliently against a stopping
 protrusion 25 of the sub-housing 20.
 The locking configuration of the housing chamber 13, 13A and the
 sub-housing 20 is described below.
 A left and right pair of guiding rails 40, separated by a specified
 distance, are provided on a lower face of a posterior end of the
 sub-housing 20 at a central portion thereof in a width-wise direction. As
 shown in FIG. 2, the guiding rails 40 are cross-sectionally hook shaped
 and mutually face one another, a protrusion 41 being formed on a posterior
 end of each guiding rail 40. When the two housings 20 and 30 have been
 correctly fitted together, a tip of the large hood member 33 reaches a
 location immediately in front of the guiding rails 40 (see FIG. 7).
 A locking arm 43 is formed between the two guiding rails 40. This locking
 arm 43 rises upwards from its posterior end (as viewed) and protrudes in
 an anterior direction. The tip of the locking arm 43 protrudes a
 prescribed distance relative to anterior ends of the guiding rails 40. A
 protruding member 44 is formed on a side face (the right face in FIG. 1)
 of the locking arm 43 at a location close to the tip 46 thereof. An
 anterior face of the protruding member 44 forms a tapered guiding face 45.
 A pair of stopping plates 50 protrude upwards from base face of a posterior
 end of the housing chamber 13. As shown in FIG. 4, these stopping plates
 50 are cross-sectionally hook shaped and are positioned back to back. The
 stopping plates 50 are capable of being inserted into the interior of the
 guiding rails 40. The length of the stopping plates 50 is shorter than the
 length of the guiding rails 40 to the extent of the thickness of the
 protrusion 41.
 A stopping member 51 is formed on an inner face of one of the stopping
 plates 50 (the stopping plate 50 on the right in FIG. 1) at a location
 close to an anterior end thereof. The stopping member 51 is capable of
 being engaged against the protruding member 44 of the locking arm 43. A
 posterior face of the stopping member 51 forms a tapered face 52 which is
 used for guiding the protruding member 44.
 An auxiliary stopping member 53 is formed symmetrically on an inner face of
 the other stopping plate 50 at a location close to a posterior end
 thereof. When the sub-housing 20 provided with the locking arm 43 is
 inserted in the housing chamber 13A from the anterior direction, the
 auxiliary stepping member 53 engages with the arm 43.
 A recess 37 is formed in the tip of the large hood member 33 of the female
 housing 30. This recess 37 is formed by cutting away a part of a lower
 face of a central portion, in a width-wise direction, of the large hood
 member 33. The tip of the locking arm 43 is capable of fitting into this
 recess 37.
 The assembly of the present embodiment is described below. Firstly, the
 frame 10 is attached to the attachment hole 2 of the panel 1 as described
 above. Next, the sub-housing 20 is inserted into the housing chamber 13 of
 the frame 10 from the posterior face thereof.
 When the posterior end of the sub-housing 20 approaches a posterior edge of
 the frame 10, the stopping plates 50 of the frame 10 approach tips of the
 guiding rails 40 of the sub-housing 20. Then, the stopping plates 50 enter
 between the two guiding rails 40 and the sub-housing 20 is pushed in.
 While this pushing-in is occurring, the protruding member 44 of the locking
 arm 43 makes contact with the stopping member 51 and, as shown in FIG. 5,
 the locking arm 43 bends to the left (relative to FIG. 5) as it is pushed
 in, the tapered faces 45 and 52 serving as guides and the auxiliary
 stopping member 53 serving as the centre. This pushing-in of the
 sub-housing 20 stops when the protrusions 41 of the guiding rails 40 make
 contact with the stopping plates 50. At this juncture, as shown in FIG. 6,
 the protruding member 44 of the locking arm 43 has passed beyond the
 stopping member 51 and reverts to its original straight condition, and a
 posterior face of the protruding member 44 is engaged against the stopping
 member 51. In this manner, the sub-housing 20 is housed within the housing
 chamber 13 in a state whereby it cannot move in an anterior or posterior
 direction.
 Next, the sub-housing 20 is fitted from an anterior direction with the
 corresponding female housing 30. At this juncture, the ribs 24 enter into
 the corresponding guiding grooves 34, and the large hood member 33 of the
 female housing 30 fits with the small hood member 23 of the sub-housing
 20, this large hood member 33 covering the outer side of the small hood
 member 23. Opposing faces of the terminal housing members 22 and 32 make
 mutual contact and are pushed in to the correct position. Thereupon, the
 stopping arm 35 of the female housing 30 engages resiliently against the
 stopping protrusion 25 of the sub-housing 20, and the two housings 20 and
 30 are latched in a fitted state.
 In addition, as shown in FIG. 7, the tip of the locking arm 43 of the
 sub-housing 20 fits with the recess 37 formed in the large hood member 33
 of the female housing 30. As a result, the bending of the locking arm 43
 is regulated even if a strong pulling force is exerted in a posterior
 direction on the female housing 30, the locking arm 43 maintains a
 retained state with the stopping member 51, and the sub-housing 20 will
 not separate from the housing chamber 13 of the frame 10.
 Moreover, if the sub-housing 20 needs to be separated from the frame 10 for
 maintenance or the like, the corresponding female housing 30 is first
 separated from the sub-housing 20. When this is done, the locking arm 43
 becomes capable of bending, a jig is inserted from an anterior direction
 into the tip of the locking arm 43, and the locking arm 43 is bent,
 thereby releasing it from the stopping member 51. Thereupon the
 sub-housing 20 is pushed from the anterior direction, separating it from
 the housing chamber 13.
 According to the embodiment described above, if the corresponding female
 housing 30 is fitted correctly with the sub-housing 20, the tip of the
 locking arm 43 will fit with the recess 37 of the large hood member 33 of
 the female housing 30, thereby regulating the bending of the locking arm
 43 and maintaining it in a latched state with the topping member 51.
 Consequently, inadvertent separation of the sub-housing 20 from the frame
 10 is prevented.
 Moreover, providing the large hood member 33 of the female housing 30 with
 the recess 37, which enables the tip of the locking arm 43 to fit therein,
 is a simple configuration which allows the female housing 30 and the
 locking arm 43 to interlock. Furthermore, the present invention is not
 limited to the embodiments described above with the aid of figures. The
 present invention may be embodied in various other ways without deviating
 from the scope thereof.