Watertight electrical contact units

A watertight electrical contact unit is integrally molded by embedding a contact member in a watertight elastic member which is watertightly secured to a body for mounting the contact unit.

BACKGROUND OF THE INVENTION 
The present invention relates to a watertight electrical contact unit, and 
more particularly, to a watertight electrical contact unit comprising a 
contact member integrally molded with a watertight elastic member. 
Recently, there has been a growing demand to an endoscope for sterilization 
and a great deal of effort has been made on the perfect water-tightness. 
An electric contact unit provided on a watertight endoscope is generally 
fixed to the endoscope with a bonding agent so as to make it watertight. A 
camera to be connected to such a watertight endoscope requires the 
water-tightness. However, it raises a problem of making an electrical 
contact unit watertight. To solve this, as shown in Japanese Laid Open 
Utility Model Publication Sho 54/1979-28291, a watertight cover which has 
been devised for an early electrical contact unit of an endoscope is 
generally employed. 
With such a conventional watertight cover, however, it is required to mount 
it on an electrical contact unit during a sterilization process, thus it 
being time-consuming. In addition, with a watertight cover mounted, the 
inside of the cover will not be sterilized with dirty portions remained. 
Furthermore, an electrical contact unit for a camera to be connected to an 
endoscope having an adhesively fixed electrical contact unit should be 
movable with respect to the fixed electrical contact unit. To this end, it 
is conceivable that the water-tightness of a movable portion is generally 
achieved by employing an O ring or the like. In this case, however, the 
connection of an electrical contact unit increases in size and water stays 
on an O ring area, resulting in poor draining, propagation of various 
germs, adherence of a disinfectant and the like. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a watertight electrical 
contact which is compact, simple in structure and reliable in 
water-tightness. 
According to the present invention, an electrical contact unit has a 
contact member whose middle portion is integrally molded with an elastic 
member of water-tightness, the elastic member being watertightly secured 
to an apparatus body so as to make the electrical contact unit watertight 
and to allow the unit to be in the contact condition with a contact 
pressure by the elastic force of the elastic member. 
Further, according to the present invention, a contact member is integrally 
molded with an elastic member of water-tightness and has no sliding part, 
so that an electrical contact unit is made watertight with a compact and 
simple structure. Thus, the electrical contact unit is impervious to water 
and medical fluid and is able to prevent adherence of water and medical 
fluid. In addition, the electrical contact unit has the outer surface of 
reduced ruggedness, so that water is easily wiped and drained.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In FIG. 1, an endoscope 1 comprises an operation portion 2, an insertion 
portion 3 extended from the operation portion 2, a universal cord 4 in 
which a light guide and the like are housed, and an eyepiece 5 provided on 
the opposite side of the insertion portion 3. The eyepiece 5 has a mount 6 
at the outer periphery thereof to which an external camera, various 
adapters and the like are connected. An adapter 7 has a front mount 
provided at the front end thereof to which the mount 6 of the endoscope 1 
is connected and a rear mount provided at the rear end thereof in which a 
television camera 8 or the like is connected to the eyepiece 5 of the 
endoscope 1. The adapter 7 includes a view finder (not shown) which 
projects from the side plane of the adapter 7 and which splits and guides 
light beams within the adapter 7. 
FIG. 2 is a sectional view of essential parts of the eyepiece 5 in the 
endoscope 1 and the adapter 7. The eyepiece 5 has an eyepiece barrel 10 
fixed to a base (not shown). An eyepiece lens 11 is mounted within the 
inside of the barrel 10 such that the lens 11 is slidable in its axial 
direction. A mount member 12 in which the mount 6 is formed on the outer 
periphery thereof and a frame 14 which holds an electrical contact member 
13 are secured to the barrel 10 by means of a screw 18. In addition, a 
holding frame 16 of a cover glass 15 is threadedly secured to the mount 
member 12. These interconnections are made watertight by providing with O 
rings or the like. The electrical contact member 13 of the eyepiece 5 is 
adhesively fixed to the frame 14. A conductor 17 is soldered within the 
electrical contact member 13. 
The adapter 7 has a tubular body 20 within which a beam splitter and the 
like (not shown) which splits light beams to an adapter lens and the view 
finder are housed. A cover glass 21 is watertightly fixed to the end of 
the tubular body 20. A mount member 22 in the adapter 7 is mounted on the 
periphery of the body 20. An adapter outer wall 23 is mounted on the 
outside of the mount member 22 with a means (not shown). In addition, an 
electrical contact member 24 in the adapter 7 which is to be in contact 
with the above stated contact member 13 is integrally molded with a 
watertight elastic member 25 which is formed of rubber in a doughnut shape 
such that part of the contact member is embedded into the elastic member. 
The elastic member 25 has its outer peripheral edge urgingly held in the 
mount member 22 and its inner peripheral edge urgingly held in the tubular 
body 20 with a holding ring 26. A conductor 27 is soldered within the 
contact member 24. A plate 28 for preventing sideways transformation of 
the elastic member is inserted between the tubular body 20 and the elastic 
member 25 which plate has an opening through which the contact member 24 
passes. 
The elastic member 25 is formed of a high disinfectant-resisting material 
such as silicone rubber. The elastic member 25 has its outer surface 
having an area to be in contact with another contact member and its inner 
surface through which a soldering portion of the conductor 27 projects and 
into which a flanged portion of the contact member 24 is embedded. In 
addition, a groove 29 is provided in the elastic member 25 around the 
contact member 24 so as to allow the contact member 24 to easily move in 
the axial direction thereof. 
When the adapter 7 is mounted on the eyepiece 5 of the endoscope 1 through 
the mount members 12, 22, the electrical contact member 24 is brought into 
contact with the contact member 13 with a contact pressure by the elastic 
force of the elastic member 25. In addition, since the electrical contact 
member 24 is integrally formed with the watertight elastic member 25, the 
contact member 24 and the elastic member 25 are placed in close contact 
with each other, so that the tubular body 20 is maintained in 
water-tightness. The plate 28 prevents the soldering portion of the 
contact member 24 from falling sideways when the contact member 24 is 
inclined and also prevents the elastic member 25 from protruding inwardly 
when the elastic member 25 is secured in place. 
FIG. 3, a second embodiment of the present invention, shows only an 
electrical contact member having an elastic member. In the second 
embodiment, in which there is a sufficient space in an electrical contact 
unit for making an electrical contact member large, an electrical contact 
member 30 which is flat and has a flanged portion 32 of a large diameter 
is integrally molded with a watertight elastic member 31. The elastic 
member 31 is in the form of a radially flat thin board, unlike the first 
embodiment, without providing a groove around the contact member 30. With 
the second embodiment, it is possible to prevent the contact member 30 
from falling sideways during connection since the contact member 30 is 
flat. 
FIG. 4 shows a third embodiment of the present invention, where the contact 
pressure of an electrical contact member is desirous to be higher than the 
elastic pressure of a watertight elastic member. An electrical contact 
member 33 has first and second flanges 34, 35. Only the first flange 34 is 
molded within a watertight elastic member 36. The electrical contact 
member 33 has its peripheral edge secured through the elastic member 36 to 
the holding frame 38 which is provided on a unit body 37. A coiled spring 
39 is interposed between the body 37 and the second flange 35 in an 
electrically insulated manner. A leaf spring or the like may be 
substituted for the coiled spring 39. 
FIG. 5 shows a watertight electrical contact member according to the 
present invention where a flexible base plate 42 on which a pattern 41 is 
formed is connected to an electrical contact member 40 in place of the 
conductor 27 soldered to the electrical contact member 24 shown in FIG. 2. 
The number of the electrical contact members to be connected to a single 
flexible base plate may be one or more. 
In the foregoing, while electrical contact units for use in endoscopes are 
described, these can be used for various purposes, not limited to 
endoscopes and for obtaining a contact pressure while in use without using 
a coiled spring, leaf spring or the like. In addition, the contact 
pressure can be optionally changed by selecting thickness, hardness and 
material of the elastic member in which the electrical contact member is 
embedded. 
The number of the electrical contact members may be one or more in the 
contact unit. The electrical contact unit of the present invention may be 
applied to both of a pair of electrical contact units.