Patent Publication Number: US-5295865-A

Title: Rubber plug for waterproof connector

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a rubber plug for a waterproof connector used mainly in a wire harness of an automobile. 
     In FIG. 14, a waterproof plug a of soft rubber for a waterproof connector has a seal portion a 2  of an oval shape extending continuously from a metal terminal-connection tubular portion a 1 , and this plug has a central wire passage bore a 3 . 
     A reinforcement member b of a synthetic resin includes a base plate portion b 1  of an oval shape having a wire passage hole b 2  formed through a central portion thereof. Support posts b 3  are formed respectively on opposite side portions of the base plate portion b 1 . The reinforcement member b is integrally connected to the waterproof plug a, with the support posts b 3  embedded in the seal portion a 3  (see FIG. 15). 
     In use, the connection tubular portion a 1  through which an electric wire w is passed is compressively clamped by a wire connection portion c 1  of a metal terminal c, and when the metal terminal c is inserted into a connector housing d, the seal portion a 2  is held in intimate contact with an inner wall of the connector housing d (Japanese Laid-Open Utility Model Application No. 1-121276). 
     When the waterproof plug a is to be automatically fed by a (component) part feeder, the oval seal portion a 2  of the waterproof plug a moves in contact with wall surfaces e 1  of a feed guide rail e of the part feeder, and at this time since the angle α of deflection of the waterproof plug a relative to the direction of movement is large, there is a drawback that the waterproof plug can not be smoothly moved. 
     SUMMARY OF THE INVENTION 
     With the above problem in view, it is an object of this invention to provide an arrangement by which an automatic feed of a waterproof plug in a part feeder can be effected smoothly. 
     According to a first aspect of the present invention, there is provided a waterproof plug comprising a sliding contact portion of a synthetic resin is formed to extend axially from a seal portion of the rubber plug which extends continuously from a metal terminal-connection tubular portion having a wire passage internal bore, said seal portion being adapted to be in intimate contact with an inner wall of a connector housing; and the rubber plug is moved with said sliding contact portion held in contact with a feed guide rail of a part feeder. 
     According to a second aspect of the present invention, there is provided a waterproof plug comprising a seal portion, adapted to be in intimate contact with an inner wall of a connector housing, extends continuously from a metal terminal-connection tubular portion having a wire passage internal bore; a sliding contact portion of a synthetic resin is formed on an end portion of said seal portion; and a pair of parallel rail contact surfaces are formed on said sliding contact portion of a synthetic resin. 
     When the rubber plug for a waterproof connector is to be fed by a part feeder, the sliding contact portion of a synthetic resin is held in contact with the feed guide rail of the part feeder, thereby making the movement of the plug smooth. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a waterproof plug for a waterproof connector provided in accordance with the present invention; 
     FIG. 2 is an axial cross-sectional view of the plug of FIG. 1; 
     FIG. 3 is a bottom view of the above plug; 
     FIG. 4 is a view showing the condition of transfer of the above plug by a part feeder; 
     FIG. 5 is a plan view of a portion of FIG. 4; 
     FIG. 6 is a front-elevational view of another embodiment of the present invention; 
     FIG. 7 is a bottom view of the construction of FIG. 6; 
     FIG. 8 is a cross-sectional view showing the above construction in use; 
     FIG. 9 is a view showing the condition of transfer of the above construction by a part feeder; 
     FIG. 10 is a perspective view of a further embodiment of the present invention; 
     FIG. 11 is an axial cross-sectional view of the construction of FIG. 10; 
     FIG. 12 is a bottom view of the above construction; 
     FIG. 13 is a view showing the condition of transfer of the above construction by a part feeder; 
     FIG. 14 is an exploded perspective view of a conventional waterproof plug for a waterproof connector; 
     FIG. 15 is an axial cross-sectional view of the above conventional plug, 
     FIG. 16 is a view showing the above conventional plug in use; and 
     FIG. 17 is a view showing the condition of transfer of the above conventional plug by a part feeder. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a rubber plug A of soft rubber for a waterproof connector has a seal portion A 2  of an oval shape extending continuously from a metal terminal-connection tubular portion A 1 , and this plug has a central wire passage bore A 3 . 
     A sliding contact portion B 1  of a synthetic resin is provided on an end portion in axis X of the seal portion A 2 . The sliding contact portion B 1  is formed integrally with a reinforcement member B embedded in the seal portion A 2  (see FIG. 2). 
     The sliding contact portion B has a pair of parallel rail contact surfaces 1 and 1 for a feed guide rail of a part feeder, the surfaces 1 and 1 extending in the direction of a longer diameter of the oval seal portion A 2 . 
     FIGS. 4 and 5 show a condition in which the waterproof plug A is fed by the part feeder D. Since the rail contact surfaces 1 and 1 of the sliding contact portion B 1  are in contact with side surfaces 2a of the feed guide rail 2, respectively, no deflection occurs, and the resistance is low, and therefore the plug is smoothly moved. 
     In an embodiment of FIGS. 6 to 8, a sliding contact portion B 1  &#39; of a reinforcement member B&#39; provided on a waterproof plug A&#39; bulges much beyond a seal portion A 2 , as at L, and rail contact surfaces 3 and 3 are extended outwardly of the seal portion A 2 , in a direction intersecting the axial direction X of the seal portion A 2 . 
     As shown in FIG. 8, the waterproof plug A&#39;, together with a wire W, is compressively clamped by a wire connection portion C 1  of a metal terminal C, and is inserted into a connector housing H. In this condition, the seal portion A 2  &#39; is held in intimate contact with an inner wall 4 of the connector housing H, and the bulged sliding contact portion B 1  &#39; is fitted in a bulge chamber 5, provided at the rear end portion of the connector housing H, thereby effecting the positioning. 
     In the above embodiment, when the waterproof plug A&#39; is to be fed by a part feeder D&#39;, the rail contact surface 3 of the sliding contact portion B 1  &#39; is in contact with an inclined side surface 6a of a feed guide rail 6, and therefore the plug is smoothly moved (see FIG. 9). 
     In an embodiment of FIGS. 10 to 12, an end face 8 of a seal portion A 2  &#34; is disposed back inward from an axial end face 7 of a slide contact portion B 1  &#34; of a reinforcement member B&#34; provided on a waterproof plug A&#34;, and indicator marks 9 are formed on the retracted end face 8. The slide contact portion B 1  &#34; has rail contact surfaces 1 and 1 as described above in FIG. 1. 
     In the above embodiment, when the waterproof plug A&#34; is to be fed by a part feeder D&#34;, the end face 7 of the slide contact portion B 1  &#34; is held against a bottom surface 6b of a feed rail 6, and the seal portion A 2  &#34; is in contact with a side surface 6a. Since the end face 7 supporting the weight offers a less sliding resistance, the plug is smoothly moved. 
     The seal portion and the slide contact portion may have any other shape (e.g. circular shape) than an oval shape. 
     As described above, in the present invention, when the waterproof plug (whose main portion is made of soft rubber) for a waterproof connector is to be fed to an assembling line by the part feeder, the plug can be smoothly moved by means of the associated sliding contact portion of a synthetic resin.