Snap-fit connector

Abstract: A hood member 12 of a snap-fit male electrical connector 10 is inserted and retained in a through hole 21 of a panel 20. A locking arm 15, having a resilient retaining claw 16 is provided on the peripheral wall face of the hood member 12. A guard 17 is formed in front of the stopping claw 16, so that even if a female connector 30 is pushed diagonally and makes contact with the guard 17, the locking arm 15 is prevented from being bent downwards, thereby accidentally releasing the connector 10 from the through hole 21.

Description: The present invention relates to a fixed-type connector, and more particularly to a fixed-type electrical connector which is supported by retaining a hood member in a through hole formed in a panel or the like. PRIOR ART Figures 4 and 5 show an example of a conventional fixed-type connector. In the diagrams, a male connector 1 has a hood member 2 formed thereon. On the peripheral wall of the upper face of the hood member 2 (as viewed) are formed cuts or slits 2a that extend in a parallel manner from the open end inwardly. Between the slits 2a is formed a locking arm 2b. The upper face of the outer extremity of the locking arm 2b has a wedge-shaped stopping claw 2b1. On the peripheral wall of the lower face of the hood member 2 is formed one or more projections 2d (Fig. 5) in a position corresponding to the stopping claw 2b1. Furthermore, an outwardly extending flange 2c is formed around the external circumference of the hood member 2 a little inwardly of the stopping claw 2b1 and the projection. A panel 3 has a through hole 3a formed thereon so as to correspond to the outer shape of the hood member 2. The hood member 2 is inserted from the inner side of the panel 3 and is retained therein. In practice, the male connector 1 is entered at an angle and the edge of the through hole 3a is fitted into the groove between the lower end of the flange 2c and the projections 2d. Then the male connector 1 is gradually brought upright until the upper end of the hood member 2 enters the through hole 3a, and the wedge-shaped fitting claw 2b1 makes contact with the edge of the through hole 3a. The locking arm 2b is pushed under and across the edge of the through hole 3a to form a snap-fitting. After the locking arm 2b is latched, the projection and the fitting claw 2b1 are located on the outer side face of the panel 3 and the flange 2c presses against the inner side face of the panel 3. The male connector 1 is thereby retained at the edge of the through hole 3a of the panel 3 so as to fit snugly therewith. Thereafter, a female connector 4 that can be inserted and thereby connected to the hood member 2 is pressed into and connected to the hood member 2 from the outer side of the panel 3. During the operation whereby the female connector 4 is connected, there is no problem in insertion if the through hole 3a of the panel 3 is in a visible position. However, if the through hole 3a of the panel 3 is not in a visible position, the operator must first find the opening of the hood member 2 by moving around a hand or the female connector 4 in the vicinity of the male connector. At this juncture, since the insertion is carried out by first searching for the opening of the hood member 2, there is a possibility of the male connector 1 becoming separated from the panel 3. As shown for example in Figure 5, the angular portion of the outer extremity of the female connector 4 can strike against the protruding end of the locking arm 2b, and the locking arm 2b may be bent downwards thereby separating the male connector 1 from the panel 3. When this happens, the entire operation must be repeated right from carrying out the attachment of the male connector 1. This is a great waste of effort, and may be extremely difficult if access to the rear of the panel 3 is restricted. The present invention has been developed after taking into consideration the above problem and aims at presenting a fixed-type connector wherein the locking arm cannot be accidentally released and separated from the panel even in the case where the through hole 3a of the panel 3 is not in a visible position. EP-A-0572012 discloses a panel connector according to the first part of claim 1 having a latch movable from a disengaged to an engaged condition in which movement of the locking arm in a releasing direction is obstructed. US-A-2891103 discloses a panel connector having a hood and a locking arm, releasing movement of which is prevented after attachment of a mating connector. SUMMARY OF THE INVENTION According to the invention there is provided a snap-fit connector for retention in an aperture of a panel, the connector having a protruding hood insertable in said aperture, a stop flange engageable with one side of said panel and a resilient locking arm engageable with the other side of said panel immediately adjacent the edge of said aperture, characterized in that said hood and locking arm are co-extensive, said hood surrounding said locking arm and the portion extending beyond the front end of the locking arm constituting a guard for the free end thereof, said guard permitting insertion of said connector in said aperture, and said guard preventing accidental bending of said locking arm by a mating connector, thereby to prevent said snap-fit connector from coming out of said aperture. According to this invention the necessarily free outer end of the locking arm is protected by the guard so that attempted attachment of the corresponding connector cannot accidentally release the locking arm by contact therewith. The guard surrounds the locking arm, and is advantageously moulded in plastic materials; this increases the strength of the connector. Preferably the hood is inclined inwardly so that the internal dimension thereof decreases progressively towards the outer edge. In this way the locking arm can make contact with the edge portion smoothly and at the desired angle since the inclined face of the hood or guard makes contact with the edge portion of the aperture and guides entry before the locking arm makes contact with the inner edge of the aperture. If the guard were not present the locking arm could make abrupt contact at a significant angle and there would be a possibility of it being damaged, but with the inclined face guiding the insertion, damage to the locking arm can be prevented. In a preferred embodiment a fixed structure constituting a stop member is formed on a side on the hood member opposite to the side having the locking arm, the stop member co-operating with the stop flange to engage the inner edge of said aperture. This arrangement is advantageous since damage to the locking arm can be prevented; the connector is inserted by pivoting about the clearance between the stop member and the stop flange, which ensures a guided insertion path. BRIEF DESCRIPTION OF DRAWINGS Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example only in the accompanying drawing in which: Figure 1 is an exploded isometric view of components illustrating the present invention; Figure 2 is a side view showing the attachment process of the male connector; Figure 3 is a partial cross-section showing the female connector making contact with the male connector; Figure 3a is a part-section corresponding to Fig. 3 and showing a groove of the locking arm; Figure 4 is a diagrammatic view of a prior art fixed-type connector; and Figure 5 is a partial cross-section view showing the prior art female connector making contact with the male connector. DESCRIPTION OF PREFERRED EMBODIMENT With reference to Figs. 1-3, a male connector 10 constitutes a snap-fit type of connector and comprises a housing 11, typically moulded of plastic, that houses and supports male terminal fittings (not shown) and a hood member 12 that extends from the edge of the housing 11 and is formed in a hood shape and surrounds the male terminal fittings. The hood member 12 of the male connector 10 is insertable into a through hole 21 formed in a panel 20. When the hood member 12 is inserted into the panel through hole 21, an approximately ring-shaped flange 13 formed on the outer circumference of the open side of the hood member 12 fits against the inner side face of the panel 20. The flange 13 need not be continuous. Furthermore, on the lower face of the hood member 12 a stop projection 14 is formed so as to be separated from the flange 13 only to the extent of the thickness of the panel 20. The upper face of the peripheral wall of the hood member 12 includes a U shaped cut or slit, to define a flexible piece extending from the inner side of the hood member 12 towards the outer end thereof. The flexible piece constitutes a locking arm 15 which is resiliently bendable towards the interior and exterior of the hood member 12. The tip of the locking arm 15 has a wedge-shaped stopping claw 16 that projects outwardly. The upright face on the inner side of the stopping claw 16 is separated from the front face of the flange 13 to the extent of the thickness of the panel 20. It is thus arranged that an edge of the through hole 21 can be inserted and retained between the wall face on the inner side of the stopping claw 16 and the front face of the flange 13. Since the upper face of the peripheral wall includes the U shaped slit, the hood member 12 extends beyond the front end of the locking arm 15. This portion will be referred to as guard 17. The outer peripheral side faces towards the open end of the hood member 12, including the guard 17, have inwardly inclined faces so that the opening decreases in the direction of the front edge. Further, the corresponding female connector 30 is formed so as to be insertable into the hood member 12 from the outer side of the panel 20. The female connector 30 supports female terminal fittings so that they face the male terminal fittings. In the present embodiment, the flange 13 is formed on the outer side face of the hood member 12 and the edge of the panel 20 is inserted and retained between the flange 13 and the stopping claw 16 of the locking arm 15. However, what is necessary is that a flexible arm bends as it makes contact with the inner side of the through hole 21 and thereby snaps resiliently over the edge of the through hole 21, for retention. Consequently, as illustrated in Fig. 3a, a groove 18 may equally be formed on the outer side face of the locking arm 15, the groove clamping the edge of the through hole 21. Furthermore, the guard 17 protects the entire extent of the locking arm 15. However, this need not be so; the guard 17 can cover the locking arm 15 to an extent sufficient to ensure that the female connector 30 or a hand cannot disturb the locking arm 15. Apart from this, although the hood member 12 is formed so as to extend around the entire periphery, it is only necessary that a hole-shaped portion be formed so as to allow insertion of the female connector 30. Accordingly, for example, the hood member 12 may equally have a configuration whereby it is partially open so that it extends in three directions from the inner side of the panel through hole 21. Moreover, in the present embodiment, although a stopping projection 14 having a fixed structure is formed on the peripheral wall on the lower face of the hood member 12, this is not necessary as long as at least one further locking arm 15 is provided. Accordingly, the peripheral wall on the lower face may equally have a similar locking arm 15. The operation of the present embodiment is as follows. As shown in Figure 2, in order to attach the male connector 10 to the panel through hole 21 of the panel 20, the male connector 10 is inclined and the lower extremity of the flange 13 is pushed against the inner side face of the panel 20. The edge of the panel through hole 21 is inserted between the flange 13 and the stop projection 14. Then, with this as axis, the upper end of the hood member 12 is pivoted so as to become horizontal (as viewed) and the outer end of the hood member 12 is inserted into the through hole 21. When the upper end of the hood member 12 passes into the through hole 21, since an inclined face is formed on the front end of the guard 17, the inclined face brushes against the edge of the panel through hole 21 and follows an arc described by the hood member 12 as it is inserted. As a result, damage to the stopping claw 16 of the locking arm 15 due to abrupt contact with the edge of the panel through hole 21 is prevented. Furthermore, since the guard 17 is connected to the hood member 12 without partitioning the hood member 12, the strength of the hood member 12 is improved. When the stopping claw 16 of the locking arm 15 passes through the panel through hole 21, the wedge-shaped stopping claw 16 brushes against the edge of the panel through hole 21, bending the locking arm 15 inwards. After the locking arm 15 crosses over the edge of the panel through hole 21, the locking arm 15 reverts elastically to its original shape and the edge of the panel 20 is clamped securely between the stopping claw 16 and the flange 13. Once the male connector 10 has been attached to the panel through hole 21 of the panel 20, the female connector 30 is inserted into the hood member 12. At this juncture, as shown in Figure 3, in the case where the hood member 12 is not visible, there is a possibility of the angular portion of the female connector 30 making contact with the edge of the open end of the hood member 12. However, as shown in the diagram, since the guard 17 covers the front side of the locking arm 15, the locking arm 15 cannot be bent downwards by accident and this prevents the male connector 10 from being separated from the panel 20. In this way, the hood member 12 of the male connector 10 is inserted and retained in the inner side of the panel through hole 21 of the panel 20. Since the locking arm 15, having the stopping claw 16 at the front end thereof, is provided on the peripheral wall face of the hood member 12, and since the guard 17 is formed in front of the stopping claw 16, even if the female connector 30 is pushed diagonally and makes contact with the guard 17 when the locking arm 15 is retaining and supporting the male connector 10 at the inner side of the panel through hole 21, the locking arm 15 is prevented from being accidentally bent downwards, thereby preventing the connector 10 from coming out.

Claims: A snap-fit connector (10) for retention in an aperture (21) of a panel (20), the connector (10) having a protruding hood (12) insertable in said aperture (21), a stop flange (13) engageable with one side of said panel (20) and a resilient locking arm (15) engageable with the other side of said panel (20) immediately adjacent the edge of said aperture (21), characterized in that said hood (12) and locking arm (15) are co-extensive, said hood (12) surrounding said locking arm (15) and the portion extending beyond the front end of the locking arm (15) constituting a guard (17) for the free end thereof, said guard (17) permitting insertion of said connector (10) in said aperture (21), and said guard (17) preventing accidental bending of said locking arm (15) by a mating connector, thereby to prevent said snap-fit connector (10) from coming out of said aperture (21). A connector according to Claim 1 wherein said hood (12) is inclined inwardly of the connector in the direction of the open end thereof. A connector according to Claim 1 or Claim 2 wherein said hood (12) comprises a substantially continuous ring. A connector according to any preceding claim and further including a stop member (14) opposite said locking arm (15), said stop member (14) defining with said stop flange (13) a groove for engagement with the edge of said aperture (21). A connector according to any preceding claim wherein said stop flange (13) is substantially continuous. A connector according to any any preceding claim wherein said locking arm (15) includes a groove (18) in the outer face thereof to engage the edge of said aperture (21). A connector according to any preceding claim and of plastic, said locking arm and guard being moulded integrally.

Inventors: OKUMURA HITOSHI, TOKUWA KOICHIRO, OKUMURA, HITOSHI, TOKUWA, KOICHIRO, Okumura, Hitoshi, c/o Sumitomo Wiring Systems, Ltd, Tokuwa, Koichiro, c/o Sumitomo Wiring Systems, Ltd
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1996
Main classification: H01R13
IPC codes: H01R13