Note: Descriptions are shown in the official language in which they were submitted.
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Field of Invention:
The field of the invention includes e]ectrolytic
treatment apparatus often found classified in the United
States Patent Office under Class 20~;
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and a process of exchanging metal on a workpiece often found
0 classified in Class 204 as well.
Description of the Prior Art:
he prior art is exemplified in United States Patents
936,472; 3,661,752; and 3,904,489; and also in French Patent
331930 and Patents in Great Britain Mumbers 760016 and 18643 (the
I latter published in 189~).
In the prior art type devices, rotary member~ for
light frictional engagement with -the cathode are shown.
~loving contact is also shown for purposes of wi~ing away
bubbles, electrodeposition, and the like, so that the electric
plating ac,ion will proceed without eontamination or film
barriers on the surface to be plated. The prior art, however,
fails to deal with the modern problems of gold plating,
partieularly as applicable to the p-Lating of contact points
on a curvilinear surface. In the plating of such contact
points, the prior art techniques have involved dipping in
the anode, and therefore plating portions of the contact which
do not require plating. Where precious metals such as goId
are employed in the plating, this overplating even to the
extent of 100%, doubles the cost of material which is a signi- ¦
ficaDt st in the gold platinq of any prod~lct Also because
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1 the prior art involves dippinq, there is no way of discretely
determining the specific area to be plated, much less deter-
mining the exact thickness to be plated on the discrete area.
SUMMARY O~ THE INVENTION
The present invention includes a method for continuous
plating of a discrete area on a convex curvilinear surface of
each of a plurality of aligned electronic contact points com-
prising the steps of: confining and oreintating the contact
points to allow movement thereof along a fixed axis of travel,
engaging the same orientated contact points to move the thus
orientated contact points with -their discrete area plated
firmly againsta plating member; applying a predetermined amount
of plating solution on the plating member to constantly wet
the same in a controllable electrodeposition quantityi
electrically energizing the contact points as a cathode and
the plating solution as an anode; rotating the plating member
to pass the plating solution on its surface onto the discrete
area of the convex curvilinear surface oE the contact points
which are passed against the plating member, whereby contact
points can be plated with a metal on the discrete area of the
convex curvilinear surface intended for electrical contact with
another member, without plating the reat portion or other
portions of the contact points which otherwise have no electri-
cal relationship in a circuit.
The invention also includes a device for continuous contact
plating of a plurality of contact points having a curvilinear
portion comprising, in combination, a plating member having an
axis of rotation and a wettable surface, a bath for electrolytic
solution for supplying such solution to said plating member, a
transport means oriented to move such contact points across
8S
l said plating member and in contact therewith, means for
positioning a plurality of contact points along a bandolier for
feeding the same into said transport means, and means for
electrically energizing such contact points as a cathode and
electrically energizing said bath as an anode, whereby the
contact points may be passed against the wettable surface of
the roller for plating of a discrete area of the curvilinear
portion of such contact points.
Furthermore, the invention includes a metallic electrical
contact element having a discrete convex curvilinear surface
portion intended for electrical contact, said surface having a
localized conductive electrodeposited contact area thereon.
The contact area decreases in thickness from the center thereof
to define a thin edge substantially free of plated metal build
up common to electrodeposition techniques using masking. Such
a contact area also has area also has substantially uniform
density. _
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1 According to an aspect of the invention, a method for plating
a discrete contact point on a carrier of electronic contacts is
disclosed.
According to another aspect of the invention is the plating
of a contact point at only the point where the same will make
electrical contact with a plated finger on a printed circuit
board, and to control the plated dimensional portion of the
contact as well as the thickness of the plated metal.
Still another aspect of the present invention is the
continuous contact plating of a plurali-ty of contacts secured
to a bandolier or carrier, the length of which may be effectively
endless.
Still another aspect of the invention is an apparatus for
carrying out the above which is readily adjustable in its basic
respects, easy to service, and economical to construct, operate
and maintain.
DESCRIPTION OF T~E DRAWINGS
Further objects and advantages of the present invention will
become apparent as the following description proceeds, taken in
eonjunction with the aeeompaying drawings in whieh:
FIG.lis a perspective partially broken rear view of the
subject continuous plate.
FIG. 2 is an enlarged partially broken view illustrating
the feed guide for delivering a plurality of bandolier secured
contact points to theopposed driving belts.
FIG. 3 is a partially diagrammatic broken view of a rear
portion of the unit taken in perspective and illustrating parti-
cularly the relationship between the opposed jaws, the plating
roller and the adjustment of the plating holder.
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1 FIG. 4 is a rear elevation of the mechanism shown in
FIG. 3 in substantially the same scale.
FIG. 5 is a partially diagrammatic view illustrating
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the drive mechanism for the carrier belts.
FIG. 6 is an end view of the mechanism shown in FIGS. 3
and 4 in slightly enlarged scale.
FIG. 7 is a top view of the jaws, driving belt, and
anode roller bro~en at the midportion thereof.
FIG. 8 is an enlarged, partially broken transverse
sectional view of the relationship between the jaws, driving
belt and roller taken along section line 8-8 of FIG. 7.
FIG. 9 is a plan view of a typical bandolier of a
plurality of contact points.
THE METHOD
The method for continuous contact plating of a curvi-
linear contact point presupposes contacts 51 in a bandolier 50
as shown in FIG. 9. The contact points are positioned so that
the bandolier is essentially perpendicular to the contact point.
Ihereafter the contact points and bando]ier are oriented to
pass the same along a longitudinal axis. ~ rol1er having an
absorbent peripheral surface is positioned for driving rotatably
with its long axis in parallel relationship to the bandolier,
and its longitudinal axis. An electrolytic bath is provided
for fluid contact with an absorbent surface on the roller. The
bandolier and its contained contact points are then moved along
the a~is parallel to the axis of the roller with the contact
points in tangential contact with the absorbent surface. The
resultant action is to follow a helical path along the absorben-t
surface of the roller with the contact points ener~ized as a
cathode, and the electrolyt-ic solution electrically energized,
particularly as to the absorbent portion of the roller, as an
anode. The method also contemplates means in pressure relation-
ship to the absorbent surface of the roller to control the amount
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of plating solution that is passed thereabout for purposes of
plating.
- THE APPARATUS
The continuous plater 10 is shown in rear elevation,
5 and perspectively, in FIG. 1. There it will be seen that the
continuous plater 10 includes a main frame 11, and a plurality
of carrier belts 12. The carrier belts 12 include an upper belt
18 and a lower belt 19, which are positioned to tangentially engage
each other and pass through the jaws 14 which orient the same
10 for tangential helical trace contact with an anode roller 15.
A plating solution tray 16 is positioned beneath the anode roller
15, and provided with an electrolytic solution for purposes of
plating, usually plating gold to the contact points. The entire
continuous plater 10 presupposes a treatmen-t to the contact
15 points prior to entering the plater and treatment thereafter. It
is therefore a continuous plater 10, as a part of a total proces-
sing apparatus for contact points.
To be noted in FIG. 1 is -the drive motor 20 for the
anode roller 15. A feed guide sprocket 21 is provided immediately
20 adjacent the feed point 60, the same being the point where the
upper belt 18 and the lower belt 19 first come into contiguous
contact for the feeding of the contact points.
Turning now to FIG. 8, it will be se;en that the jaws
14 include an upper jaw 42 and a lower jaw 44. The same are
25 secured to jaw bracket 41 which is permanently affixed to the
frame 11 of the continuous plater 10. The bandolier 50 is
grasped by the opposed upper belt 18 and lower belt 19, and so
positioned that the contact point 56 is in contact relationship
- with the absorbent sleeve 24 of the roller 15. A meter roller
30 22 is provided for adjustable pressure contact against the
porous sleeve 24, so that as the roller passes through the
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1 electrolyte 58, the amount of retained fluid after
passing the metering roller 22 can be controlled by
adjustment. The upper and lower belts 18, 19 may be of a
closed cell foam like material, or solid rubber,
depending upon the contacts being fed.
The roller 15 allows transfer of the electrolytic
solution from the plating solution tray 16 to roller 15
and subsequently to the contact points. This is
preferably accomplished by use of the absorbant sleeve
24; however, other alternatives are possible. The
important feature is that the roller must transfer the
plating solution from the solution tray to the electrical
contact point or controllable electrodeposition quantity.
The contacts, while generally secured to a
bandolier, may take varying forms. As shown in FIG. 9,
the bandolier 50 has a plurality of contacts 51 secured
thereto by means of a fastener 52, in this instance
opposed jaws. The band 54 is provided with a plurality
of drive holes 55 which permit it to be sprocket fed for
movement.
The electrical contacts 51 shown in the enlargement
of FIG. 8 have the metal plated areas 100 which form the
electrical contact points. The thickness of the contact
points decreases radially outward from the center thereof
and each contact point joins with the body of the contact
51 at the thin edge 102. Thus, it can be appreciated
that the thickness of the contact points decreases to
provide an essentially flush junction with the underlying
support portion of the contact. Furthermore, the inter-
action of the rotating roller and the movement of thecontacts reduce the~
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1 15 is secured to a roller frame 25 which includes a pair of
roller frame legs 26, a roller frame base 28, and opposed roller
frame posts 29 to which the roller 15 is mounted. The roller
frame legs 26 are mounted at a pivot 30 to the main frame 11.
A horizontal adjusting member 31 is provided at each end of the
lower frame 25, immediately adjacent the pivot 30. Vertical
adjustment means 32 are provided beneath the base 28 of the
roller frame 25, and as noted in FIG. 4, by rotating the knob
34, the pads 59 bear upon the lower face of the base 28, and
raise and lower the same. Here it will be appreciated that the
adjustment takes a very modest arcuate path, but the same is of
no major movement inasmuch as the adjustment of the roller 15 with
regard to the position of the jaws 14 and the contained bandolier
50 is empirical.
Turning now to FIG. 5 it will be seen that the upper
and lower belts 18, 19 are driven by a belt motor 35 through
a given sprocket mechanism to a plurality of belt pulleys 36.
The upper belt and lower belt 18, 19 are reeved around the
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pulleys to insure a firm flow and continuous drive. The
motor braket 38 permits some adjustment of the belt motor 35,
and cooperates with the idler adjustment 40 (see Fig. 1) to
adjustably secure the tension and frictional engagement of the
belts 18, 19 with the pulleys 36.
In Fig. 6 the bracket 45 for the metering rollersS~dis-
closed, the same being urged by the spring 46 into compressive
relationship with the roller 15. An adjustment nut 48 is provided
to further adjust the yieldable relationship between the metering
roll 22 and the anode roller 15, the bracket 45 being pivoted
arund pivot point 49.
It is highly desirable to lead the bandolier 50 into
the feed point 60 defined by the position where the upper belt
18 and lower belt 19 come together, the alignment to be as close
as possible. It will be appreciated that to accomplish this
purpose, a feed guide sprocket assembly 21 may be usefully
employed (see Fig. 2). The assembly comprises an upper inner
toothed wheel 61 and an upper ~uter toothed wheel 62. The teeth
66 are positioned circumferentially to penetrate the drive holes
55 of the bandolier 50. The driving effort of the upper and
lower belts 18, 19, will rotate the toothed w~ee~ 61, 62, and
pull the bandolier 50 between the teeth 66 and the lower inner
guide wheel 64 and the outer lower guide wheel 65. Other alterna-
tives are available for the feed guide sprocket assembly 21, such
as a pair of opposed plates. The principal result to be achieved
is one of presenting the bandolier 50 in a path substantially co-
incident with the feed point 60, and the trace of the upper and
lower belts 18, 19 as they pass through the opposed jaws 42,44.
For purposes of cleaning, an eccentric tray mount assembly
30 70 (see Fig. 1) in which a single crank 71 may be rotated to the
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end that the four contact rollers 72 suppor~ing the tray 16 lower
their contact points, and the tray 16 may be removed from its
fluid bath relationship with the roller 15 for cleaning,
replenishing the electrolytic solution, or otherwise engaging
in the maintenance and operation of the subject continuous
plater 10.
~l-though particular embodiments of the invention have
been shown and described in full here, there is no intention to
¦ thereby limit the invention to the details of such em~odiments.
L0 ¦ On the contrary, the intention is to cover all modifica-tions,
~ alternatives, embodiments, usages and equivalen-ts of a continuous
¦ contact plater and method as fall within the spirit and scope of
he invention, s eclf~cation and the appended ~laim .
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