Device for fastening at least one plate inside an electrolyte bath and for feeding current thereto

A device for fastening at least one plate inside an electrolyte bath and for feeding current thereto, which device comprises at least two electrically-insulated battens which run next to one another and between which the plate should be arranged with the flat sides thereof facing the battens, at least one of said battens comprising an imbedded electrical conductor which can be connected to the current source, and the device further comprises means to push the battens towards one another, said means being completely electrically insulated from the conductor while the means for insuring the electrical contact between the conductor and the plate are comprised of projections extending from that side facing the other batten of the first-mentioned batten with the electrical conductor, said projections contacting the conductor and passing cross-wise through said batten insulation, said projections engaging the plate when clamping said plate between both battens.

BACKGROUND OF THE INVENTION 
The invention relates to a device for fastening at least one plate inside 
an electrolyte bath and for feeding current thereto, which device 
comprises at least one electrically-insulated batten wherein at least one 
electric conductor is imbedded, which conductor can be connected to a 
current source, and means to insure the electric contact between the 
conductor and the plate. 
Such devices are notably used for manufacturing so-called printed circuits. 
A plate from electrically-insulating material having already some metal 
plating, is arranged thereby inside an electrolyte bath and by feeding 
current to said plating, metal is caused to precipitate over the complete 
plating or according to a determined pattern by covering partly said 
plating. 
In known devices of this kind, one or a plurality of such battens with an 
imbedded conductor are so fastened substantially vertically to a cathode 
bus bar that said battens are immersed into the electrolyte bath. Inside 
the bath proper, to said batten are fastened clamps which are also 
electrically insulated by means of a synthetic material coating, but not 
in those locations where said clamps are to contact the plate. The 
conducting core of said clamps is connected to the batten conductor. The 
clamps proper are tightened down on a plate by means of screws. Due to 
said screws and wear, the clamp insulation is quite rapidly damaged. As 
soon as the insulation is removed, there also occurs a plating of the 
clamps proper which thus means a loss of material. 
When removing the metal plating from the clamps, there is again a danger 
that the clamps will be further damaged, whereby during the following use 
still more clamp plating will occur. 
With other devices, the clamps are formed by springs which engage the 
batten conductor by means of a bolt. The above-described drawbacks are 
also to be found in these latter devices. 
In still further devices, the clamps have no screw but the device comprises 
two battens which are immersed vertically in the bath, and which are 
provided on the sides thereof facing one another with contact springs with 
a groove, the plate being clamped with the upstanding edges thereof 
between said springs. Not only there is still obtained some precipitating 
on the springs but also due to the contact springs engaging two facing 
edges of the plate, with other plate sizes said springs and thus also the 
battens with the conductor have to be moved. 
Now to solve the problems of metal plating on the clamps, it has already 
been proposed not to immerse the clamps in the electrolyte bath but to 
retain same above said electrolyte bath. With this solution, there is thus 
no problem with metal plating of the clamps, but part of the plates has to 
project above the electrolyte bath and thus is not used purposefully. 
SUMMARY 
The invention has now for object to obviate all of the above drawbacks and 
to proide a device for the fastening of at least one plate inside an 
electrolyte bath and the feeding of current thereto whereby the plate can 
still be completely immersed in the electrolyte bath but whereby not only 
the plate fastening can occur very fast but also the precipitating of 
metal on the device is substantially avoided and the damaging of said 
device by the cleaning or the plate fastening is substantially excluded. 
For this purpose the device comprises at least two electrically-insulated 
battens which run next to one another and between which the plate should 
be arranged with the flat sides thereof facing the battens, at least one 
of said battens comprising an imbedded electric conductor which can be 
connected to the current source, and the device further comprises means to 
push the battens towards one another, said means being completely 
electrically insulated from the conductor while the means for insuring the 
electric contact between the conductor and the plate are comprised of 
projections standing on that side facing the other batten of the 
first-mentioned batten with the electric conductor, said projections 
contacting the conductor and passing cross-wise through said batten 
insulation, said projections engaging the plate when clamping said plate 
between both battens. 
In a particular embodiment of the invention, the batten provided with at 
least one conductor is comprised of a batten from insulating material 
wherein at least one conductor is imbedded and the insulating material of 
which has by itself a strong enough mechanical strength to clamp a plate 
together with the other batten. 
In a peculiar embodiment of the invention, the means for pushing the 
battens together are comprised of bolts and nuts. 
In an advantageous embodiment of the invention, both battens are provided 
with at least one conductor. 
In an useful embodiment of the invention, that batten provided with at 
least one conductor has two conductors running along the lengthwise 
direction thereof, in such a way that when the battens are pushed 
together, the edges of at least two plates lying on either sides of said 
batten can be clamped between both battens.

Both devices for fastening a plate and feeding current thereto as shown in 
the figures, are mounted inside a bath 1 filled with electrolyte 2. The 
electrolyt level is shown in 3. The devices are completely immersed in the 
electrolyt 2. 
Each one of said device comprises three pairs of cooperating clamping 
battens 4 and 5. The clamping battens 4 and 5 in each pair are identical. 
The battens 4 in the three pairs are further connected at the ends thereof 
by connecting battens 6 to form a framework. The clamping battens 4 and 
consequently also the clamping battens 5 run thereby in parallel 
relationship to one another and at right angle to the connecting battens 
6. A framework thus formed by battens 4, 5 and 6 can be arranged in bath 1 
both with the clamping battens 4 and 5 thereof vertical and with the 
battens 4 and 5 horizontal. In the framework shown at the left in figure 
1, the battens 4 and 5 lie horizontally while in the framework shown on 
the right in figure 1, the battens 4 and 5 run vertically. 
The battens 4 and 5 in each pair are joined together by means of bolts 7 
and nuts 8 screwed thereon. With these bolts 7 and nuts 8 the battens 4 
and 5 in each pair can also be pushed together in such a way that a plate 
9 to be coated electrolytically can be clamped therebetween. 
The connecting battens 6 are entirely made from plastics. The battens 4 and 
5 in each pair are also made mainly from plastics but they have one or 
several metal conductors 10 imbedded therein. The plastic material of the 
battens 4 and 5 does not comprise a simple coating of the conductors as 
without said conductors 10, the battens 4 and 5 would have enough strength 
in themselves to clamp the plate 9. 
The battens 4 and 5 in both outermost pairs in each framework 4, 5, 6 have 
but one conductor 10. Said conductor 10 is formed by a bar which extends 
substantially over the whole length of the batten 4 or 5 but which has 
however a width and thickness which is smaller than the width and 
thickness of the batten 4 or 5 proper. Said conductor 10 lies closer to 
that edge facing the middle pair of battens 4 and 5, of the batten 4 or 5 
than to the other edge. The conductor 10 enters actually completely inside 
a groove 11 which opens on said edge. The width of conductor 10 is smaller 
than the groove depth. The conductor 10 lies as far down as possible in 
groove 11 and the remaining portion of said groove is sealed with a strip 
12 from plastic electrically-insulating material. The various bolts 7 go 
through openings 13 in battens 4 and 5 in said outermost pairs, said 
openings 13 lying completely next to the conductors 10. Said bolts 7 can 
be made from metal as they do not contact any conductor 10. The conductors 
10 in both battens 4 and 5 in each outermost pair are further connected to 
a current source by means of a conductor also provided with an insulation, 
which is not shown in the drawings for clearness sake. 
A number of small metal pins 14 further stand on each one of the battens 4 
and 5 in each one of said latter outermost pairs of battens. Said pins 14 
engage the conductor 10 of the corresponding batten, for instance by being 
clamped in the conductor, projecting through the plastics surrounding said 
conductor and projecting somewhat out of the batten, on that side facing 
the other batten in the pair. The pins 14 on both battens 4 and 5 in a 
pair lie exactly opposite one another. 
The battens 4 and 5 in the middle pair of each framework 4, 5, 6 each 
comprise two conductors 10. Said conductors 10 are imbedded in the same 
way as for the above-described battens 4 and 5 inside a groove 11 in said 
battens and they have identical shapes. A batten 4, 5 of the middle pair 
thus encloses adjacent each one of the lengthwise edges thereof, a 
batten-shaped conductor 10 which is completely imbedded in the batten and 
completely insulated. Both conductors 10 of a batten 4 or 5 in the middle 
pair are connected either singly or jointly to a current source, by means 
of a completely electrically-insulated conductor which has not been shown 
in the figures for clearness sake. The bolts 7 go through openings 13 in 
the battens 4 and 5 of said middle pair, said openings 13 lying precisely 
between both conductors 10 in each batten 4 and 5. Said battens 4 and 5 
are also provided with small pins 14 on those sides thereof facing one 
another. A series of pins 14 is connected to each conductor 10 and they 
project slightly out of the plastics from the batten. Opposite each pin 14 
standing on batten 4 also lies a small pin 14 standing on batten 5. 
Between the middle pair and each one of the outermost pairs of battens can 
be clamped a number of plates 9 to be treated electrolytically. The number 
of plates is dependent on the length of battens 4 and 5 and on the plate 
size. In FIGS. 2 and 3 but two plates 9 have been shown, namely one plate 
between the middle pair of battens 4, 5 and each outermost pair of battens 
4, 5 respectively. Each one of said plates thus lies clamped with the one 
edge thereof between both battens 4,5 in an outermost pair, and with the 
opposite edge thereof clamped between the nearest portion of the middle 
pair of battens 4,5. Care is taken to avoid said plates 9 contacting bolts 
7. When the nuts 8 are tightened on said bolts 7, the battens 4 and 5 are 
pushed together whereby thus one edge of plate 9 is clamped between same 
and more precisely between the small pins 14 thereof. The plate 9 is thus 
not only retained in a fast and reliable way, but also the plate 9 lies 
with each flat side thereof against the pins 14 to be connected 
therethrough to the conductor 10 they connect with. As both battens 4 and 
5 of each pair are connected separately to the current source, both flat 
sides of plate 9 are also fed current separately. By regulating the 
current it is thus possible to plate the one side of plate 9 faster than 
the other side or consequently for a determined dwell time of the plate 
inside the bath, to obtain a thicker electrolytic layer on the one side of 
plate 9 relative to the other side. The current distribution is perfect in 
such a way that the electrolytic layer on each plate side is quite 
homogeneous. To the exception of the slightly protruding ends of the small 
pins 14, no live metal parts of the device lie in contact with the 
electrolyte which excludes precipitating thereon. A possible plating of 
the pins 14 can easily be removed. During such removing there is but a 
slight danger of damaging the battens 4 and 5 and even if some damage were 
to occur, there is still but slight danger that the conductor 10 in said 
battends will be exposed thereby. The device does not comprise clamps the 
insulation of which can wear down. The battens are pushed together by 
bolts which as they do not contact the plates nor any other live part, can 
even be made from metal without any danger of metal precipitating thereon 
from the electrolyte bath. 
The above-described devices are particularly suitable for those cases where 
a plate 9 should not only be retained inside the elecrolyte bath 1 but 
also fed with current. It is of course clear that the same devices can 
also be used when no current is to be fed to the plate, in such a way that 
with a cycle in which for instance insulating plates should first be 
plated chemically with metal, thus without being fed current, and in a 
further step should be plated with current being fed thereto, the same 
devices can be used for both operation steps. 
It must be understood that the invention is in no way limited to the above 
embodiments and that many changes can be brought therein without departing 
from the scope of the invention as defined by the appended claims. 
Particularly the device does not have to comprise a plurality of 
cooperating batten pairs which are joined into a framework. The device can 
be comprised only of a pair of such battens. 
Both battens in each pair do not have either to be necessarily provided 
each with a conductor. When for instance the plate should be plated 
electrolytically but on one side thereof, it is sufficient to provide a 
conductor in the batten on that side. By "feeding current to the plate" 
there should always be understood the feeding of current to the metal 
plating when the plate is formed by an insulating sheet and a conducting 
plating thereof. 
The means for pushing the plates together should not necessarily be 
comprised of bolts and nuts. The way in which said battens are pushed 
together is not critical, as there is no problem of any metal 
precipitating on said means which do not contact anyway any live part. 
In that case where the fastening device comprises a plurality of batten 
pairs as described above, it is not required that each batten in the not 
outermostlying pairs comprises two conductors. Such battens can for 
example comprise but one conductor to which connect two series of pins. 
The pins which stand on the battens in one and the same pair should not 
necessarily be directly facing one another. Said pins may for example be 
staggered. 
The projections provided on the battens should not however absolutely be 
pins. They could also be comprised of small elongated ribs. 
The connecting battens of the frameworks should not necessarily be made 
entirely from synthetic material. They could also comprise an imbedded 
conductor which connects directly to the conductors of the battens 
connected thereto, said latter conductors might be connected through the 
connecting batten conductor and possibly an insulated conductor joined 
thereto, to the current source. 
While a preferred embodiment of the present invention has been described in 
detail not only for purposes of illustrating and the advantages of the 
details thereof, with mentioned variations, further embodiments 
modifications and variations are contemplated according to the broader 
aspects of the present invention, all as determined by the spirit and 
scope of the following claims.