Electrical connectors – Coupling part including flexing insulation – Sealing
Reexamination Certificate
2000-01-18
2001-06-26
Abrams, Neil (Department: 2839)
Electrical connectors
Coupling part including flexing insulation
Sealing
C439S275000
Reexamination Certificate
active
06250962
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates to a sealing plug, in particular a one-piece type rubber plug for a watertight connector through which plug box-shaped terminal fittings can be inserted. The present invention also is directed to a rubber plug for a watertight connector through which plug terminal fittings having stabilizers are suitably insertable. Furthermore the invention relates to a watertight connector having such a sealing plug.
2. Description of the Related Art.
A prior art one-piece waterproof rubber plug is fittable into an opening in the rear surface of a housing. The housing is formed with cavities and insertion holes are formed in positions in the prior art plug that correspond to the respective cavities. A wire with a terminal fitting at its end is inserted into the housing by first inserting the terminal fitting through the insertion hole of the prior art plug. This insertion of the terminal fitting through the insertion hole causes a widening the insertion hole. The terminal fitting eventually passes through the insertion hole and is accommodated in the corresponding cavity of the housing. The insertion hole then is restored elastically to its original smaller shape, and comes into sealing contact with the outer surface of the wire to provide a secure sealing. If the terminal fitting is box-shaped, the inner surface of the insertion hole may be scratched or damaged by the corner of the box and sealability may not be secured.
A known rubber plug that is used for box-shaped terminal fittings is disclosed in European Patent Application Publication No. 0 407 863 and is shown in FIG.
21
. This prior art rubber plug is shaped such that the insertion hole
1
is rectangular at an entrance side in conformity with the outer configuration of the terminal fitting
5
and circular at an exit side so that the insertion holes
1
can be held in sealing contact with the outer surface of wire
6
. Further, hollow escape portions
4
are formed around the circular holes
2
.
Accordingly, when a box-shaped terminal fitting
5
is inserted, an inner portion
3
of the circular hole
2
displaces toward the escape portion
4
, and prevents the inner surface of the circular hole
2
from being scratched or damaged.
The inner portion
3
around the circular hole
2
should come into sealing contact with the outer surface of the wire
6
. However, the inner portion
3
is thinned in the prior art construction by forming the escape portion
4
around the circular hole
2
. This results in an insufficient elastic force, which is not necessarily satisfactory in view of sealability.
Moreover, many prior art terminal fittings have been formed with stabilizers in recent years to stabilize the insertion of these terminal fittings into cavities and to prevent an upside-down insertion. Insertion of such a prior art terminal fitting may cause the stabilizer to scratch or damage the inner surface of the insertion hole or to damage the stabilizer, thereby resulting in insufficient sealability. As a result, the terminal fittings that have stabilizers cannot be used when this prior art one-piece type rubber plug.
The present invention was developed in view of the above problems and an object thereof is to provide a waterproof plug and a watertight connector, which have a high sealability and which are prevented from a scratch or damage caused by portions of terminal fittings.
SUMMARY OF THE INVENTION
According to the invention, a sealing plug is provided for a watertight connector. The sealing plug is used with at least one wire that has a terminal fitting secured to its end. The wire and the terminal fitting are insertable into the sealing plug. The sealing plug is formed with at least one insertion hole which is sufficiently engageable with the outer surface of the wire to substantially prevent the intrusion of water. One or more slits are formed in the inner surface of the insertion hole in positions that correspond to one or more portions of the terminal fitting. The slits preferably extend from the inner peripheral surface of the insertion hole towards the outer periphery of the sealing plug. The slits also may be provided in positions that correspond to corner portions of the terminal fitting.
According to a further preferred embodiment of the invention, a rubber plug is provided for a watertight connector. The plug is used with at least one wire that has a box-shaped terminal fitting secured to its end. The plug is formed with at least one round hole which is dimensioned to be sufficiently engageable with the outer surface of the wire to prevent the intrusion of water. Slits are formed in the inner surface of the insertion hole in positions that correspond to corner portions of the terminal fitting. Thus, the terminal fitting can be inserted into the hole of the plug such that the corner portions of the terminal fitting enter the slits. Advancement of the terminal fitting into the insertion hole elastically forces the slits to be open more widely. The insertion hole elastically narrows after the passage of the terminal fitting. Hence the slits close and come into sealing contact with the outer surface of the wire. Thus, even if the terminal fitting is box-shaped, the inner surface of the insertion hole is prevented from damage and can be held elastically in sealing contact with the outer surface of the wire over its entire circumference, thereby providing a secure sealing function.
Tapered guide surfaces preferably are formed at an entrance end of the insertion hole to guide the terminal fitting into an orientation where the corner portions of the terminal fitting align substantially with the slits. Thus, the corner portions of the terminal fitting are guided by the guide surfaces to correct the orientation of the terminal fitting. As a result the corner portions will align automatically with the slits even if the terminal fitting is displaced slightly in a circumferential direction when being pressed against the entrance end of the insertion hole. Since it is not necessary to pay much attention to the orientation of the terminal fitting during the insertion, the terminal fitting can be inserted efficiently. The slit may be formed in the inner surface of the insertion hole in a position corresponding to a stabilizer of the terminal fitting.
According to a further preferred embodiment, a rubber plug is provided for a watertight connector. The connector includes a housing that has at least one cavity and the plug may be mounted to the rear end of the housing. The plug is formed with at least one insertion hole in a position on the plug that aligns with the cavity in the housing. The insertion hole is provided for receiving at least one wire that has a terminal fitting secured at its end. The terminal fitting is formed with a stabilizer for stabilizing the orientation of the terminal fitting during the insertion of the terminal into the cavity. A slit is formed in the inner surface of the insertion hole in a position that corresponds to the stabilizer of the terminal fitting.
The terminal fitting can be inserted into the insertion hole with the stabilizer aligned with the slit. Thus the stabilizer forcibly enters and advances along the slit. After the passage of the terminal fitting, the insertion hole elastically narrows and the slit closes into sealing contact with the outer surface of the wire.
The slit for the stabilizer enables the terminal fitting to pass through the insertion hole without damaging or scratching the inner surface of the insertion hole. Thus secure sealing can be provided between the wire and the insertion hole. The terminal fitting with the stabilizer can be used for the watertight connector to ensure sealability, and the terminal fitting can be inserted stably into the cavity while the upside-down insertion of the terminal fitting is prevented.
Preferably, at least one tapered guide surface is formed at an entrance end of the insertion hole for guiding the terminal fitting to a position where the stabilizer is aligned
Abrams Neil
Casella Anthony J.
Hespos Gerald E.
Porco Michael J.
Sumitomo Wiring Systems Ltd.
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