Improvements in Rheostats for Regulating the Current used in Electro-plating and other Processes.
Year: 1898

page_text: Improvements in Rheostats for Regulating the Current used in
Electro-plating and other Processes.
A communication from The ZUCKER AND LEVETT AND LOEB COMPANY, of New
York, in the County and State of New York, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, Civil Engineer,
do hereby declare the nature of this invention to be as follows:-
-
The primary object of this invention is to provide a convenient, cheap and
effective regulator applicable to regulating or controlling the amount of current
flowing through a plating tank; it being desirable to keep a constant potential
at the terminals of said tank and provide means to increase the current in pro-
portion to the decrease of resistance (or increase of surface of the work in the
plating tank) and to decrease the current under (and in direct proportion to)
changes in the opposite direction. It is also applicable in other relations to
control the strength of the electric current.
The invention consists of a number of resistance strips of different capacities
arranged in parallel and connected electrically to a conductor at one end, and
separated electrically at the opposite end, in combination with a suitable device
by means of which one or more or all of the resistance strips may be interposed
in the circuit.
It is convenient to make a regulator wholly independent of any other mechanism,
and the rheostat may therefore be mounted upon a suitable support or frame;
this may consist of any suitable support, a convenient form being that in which
the frame consists of end pieces and braces, the whole being attachable by feet.
A suitable metal strip is secured to but insulated from the frame, and to this
strip a leading out conductor is attached through the binding post. To a part,
furthermore, are suitably secured the ends of resistance strips. The opposite
ends of these strips are each secured to suitable contact parts arranged in an arc
and electrically separated from each other.
A leading out conductor is secured to a suitable binding post electrically_con-
nected by means of a strip to a fan shaped switch provided with an insulated
handle and having a contact part corresponding in configuration to an arc formed
by parts and adjusted relatively thereto to bear against such parts when the
switch is brought opposite to them. The contact part and leading out conductor
are electrically connected through the pivot or otherwise in any suitable manner.

page_text: The scope of movement of the switch may be limited by suitable detents if desired
on the frame.
In an example of the invention the resistance strip is twice the electrical resistance
and one half the sectional and superficial area of the other resistance strips, and any
one of the resistance strips is of such size that it will safely stand the entire potential
of the dynamo with which it is to be used without injurious heating.
If now work having a certain superficial area be placed in the tank, and the
switch placed so that the current will travel only through resistance strip and it
be found that a current of 50 amperes is flowing (this being the current desired)
and that an electric pressure of two volts be maintained at the terminals of the
tank, then to get the proper conditions, with treble the superficial area of work
in the tank, would require 150 amperes or three times the current, which will be
obtained by moving the switch so as to put strips into the circuit. The conditions
would then be, resistance in rheostat one third of former resistance, and the
current will be three times the former current, or 150 amperes, the electrical
pressure 2 volts at terminals of tank. Since the electrical pressure at dynamo is
assumed to be constant, and in practice is nearly so, and as the relative resistance
of tank and rheostat under proper working condition is always the same, it
follows that a constant pressure will be maintained at terminals of plating tank.
By the use of the conductors in parallel the radiating surface is increased in
proportion to the currents carried, so that when carrying the maximum current
the strips are all brought up to the highest safe temperature. Every part of the
resistance strips is therefore working to its fullest capacity.
In another example of the invention in which a sliding switch is employed, the
contact parts are disposed in a straight line, and the switch slides between the
piece under the strip which is electrically connected through the binding post
to a suitable leading out wire and the pieces which keep it in line with the contact
ends. Projecting parts are disposed in the path of the handle to limit the scope
of movement at each side of the sliding switch.
By the use of several strips of the same sectional and superficial area and
resistance in parallel with each other and with one strip of one half the sectional
and superficial area and resistance of the others it is possible to get a greater
number of graduations of resistance than the number of resistance strips employed.
Thus if a certain fixed electrical pressure be maintained at the terminals of the
rheostat and such pressure is found sufficient to force 50 amperes through the
narrow strip it would force 100 through any one of the other strips. Therefore
starting the switch at the extreme left at the strip and moving the switch toward
the right, currents would be obtained of 100, 200, 300, 400, 500, 600 and 650
amperes; and starting with the switch at the extreme right, and moving the
switch to the left, currents of 50, 150, 250, 350, 450, 550 and 650 amperes would
be obtained. It is therefore possible to get 13 different combinations for seven
resistance strips, and thereby afford a more complete and finely graduated control
of the current.
The switch described for throwing in and out of circuit the resistance is the
most convenient for practical purpose, but the invention is not limited to that
form of switch, as other switches may also be employed for the purpose if desired,
and the parts may be placed in one or more straight rows instead of in the arc
form without departing from the invention.
By the employment of this invention, there is great saving in metal and frame
work, and a rheostat is produced which is much lighter, cheaper and better 5
adapted to nice graduations of current than any which have heretofore been devised
so far as is known to my correspondents.
In one example of the invention the strips need not be extended in a straight
line of the length of resistance required, but may be folded upon themselves in
any manner desired. Furthermore the strips may be covered with or enclosed in 5
any suitable material such as is well known in the art and the strips are not
limited to any one form, but wires may also be employed if desired, and a greater

page_text: or smaller number of resistances may be employed, and also more than one
fractional resistance may be employed depending upon the number and character
of graduations desired.
041 1
T
1900
Improvements in Rheostats for Regulating the Current used in
Electro-plating and other Processes.
A communication from The ZUCKER AND LEVETT AND LOEB COMPANY, of New
York, in the County and State of New York, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for Foreign
Patent Solicitors, G, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, Civil Engineer,
do hereby declare the nature of this invention and in what manner the same is
to be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
The primary object of this invention is to provide a convenient, cheap and
effective regulator applicable to regulating or controlling the amount of current
flowing through a plating tank; it being desirable to keep a constant potential
at the terminals of said tank and provide means to increase the current in pro-
portion to the decrease of resistance (or increase of surface of the work in the
plating tank) and to decrease the current under (and in direct proportion to)
changes in the opposite direction. It is also applicable in other relations to
control the strength of the electric current.
The invention consists of a number of resistance strips of different capacities
arranged in parallel and connected electrically to a conductor at one end, and
separated electrically at the opposite end, in combination with a suitable device
by means of which one or more or all of the resistance strips may be interposed
in the circuit.
In the accompanying drawings which illustrate examples of the invention
Figure 1 is a plan view, and Figure 2 is a side view of one form of device, and
Figure 3 is a plan view, and Figure 4 is a side view of another form of device,
all including the invention.
It is convenient to make a regulator wholly independent of any other mechanism,
and this rheostat is therefore shown mounted upon a suitable support or frame A;
this may consist of any suitable support, a convenient form being that shown in
the drawings in which the frame consists of end pieces zy, and braces ¹; the
whole being attachable by the feet w w. B is a suitable metal strip secured to,
but insulated from the frame A, and to this strip a leading in conductor a is
attached through the binding post a¹. To the part B furthermore are suitably
secured the ends of resistance strips b c d e f g and h. The opposite ends of
these strips are each secured to suitable contact parts ii, arranged in an arc, and
electrically separated from each other.
A leading out conductor is secured to a suitable binding post ¹ electrically con-
nected by means of the strip k to the fan shaped switch m, provided with an insu-
lated handle n and having a contact part 7, corresponding in configuration to

page_text: the arc formed by the parts ii and adjusted relatively thereto to bear against
such parts when the switch m is brought opposite to them. The contact
part and leading out conductor j are electrically connected through the pivot H
or otherwise, in any suitable manner. The scope of movement of the switch m
may be limited by suitable detents pg if desired on the frame A.
In the example of this invention shown in the drawings the resistance strip b
is twice the electrical resistance and one-half the sectional and superficial arca
of the other resistance strips, and any one of the resistance strips is of such size
that it will safely stand the entire potential of the dynamo with which it is to be
used without injurious heating.
If now work having a certain superficial area be placed in the tank, and the
switch m placed so that the current will travel only through resistance strip b
and it be found that a current of 50 amperes is flowing (this being the current
desired) and that an electric pressure of two volts be maintained at the terminals
of the tank, then to get the proper conditions, with treble the superficial area of
work in the tank, would require 150 amperes or three times the current, which
will be obtained by moving the switch so as to put strips 6 and c into the
circuit. The conditions would then be, resistance in rheostat one-third of former
resistance, and the current will be three times the former current or 150 amperes,
the electrical pressure 2 volts at terminals of tank. Since the electrical pressure
at dynamo is assumed to be constant, and in practice is nearly so, and as the
relative resistance of tank and rheostat under proper working condition is always
the same, it follows that a constant pressure will be maintained at terminals of
plating tank. By the use of the conductors in parallel the radiating surface is
increased in proportion to the currents carried, so that when carrying the maximum
current the strips are all brought up to the highest safe temperature. Every
part of the resistance strips is therefore working to its fullest capacity.
In Figures 3 and 4 another example of this invention has been shown in which
a sliding switch m² is employed. In this example of this invention the contact
parts are shown disposed in a straight line, and the switch m¹ slides between
the piece r, under the strip which is electrically connected through the binding
post to a suitable leading out wire, and the pieces ss which keep it in line
with the contact ends i i. Projecting parts p and q are disposed in the path
of the handle n¹to limit the scope of movement at each side, of the sliding
switch m¹.
By the use of several strips of the same sectional and superficial area and
resistance in parallel with each other and with one strip of one-half the sectional
and superficial area and resistance of the others it is possible to get a greater
number of graduations of resistance than the number of resistance strips employed.
Thus, if a certain fixed electrical pressure be maintained at the terminals of the
rheostat and such pressure is found sufficient to force 50 amperes through the
narrow strip 6 it would force 100 through any one of the other strips. Therefore,
starting the switch m, at the extreme left, at the strip h, and moving the switch
toward the right, currents would be obtained of 100, 200, 300, 400, 500, 600 and
650 amperes; and starting with the switch at the extreme right, and moving
the switch to the left, currents of 50, 150, 250, 350, 450, 550 and 650 amperes
would be obtained. It is therefore possible to get 13 different combinations for
seven resistance strips, and thereby afford a more complete and finely graduated
control of the current.
The switch m, which has been shown as the device for throwing in and out of
circuit the resistance, is the most convenient, it is believed, for practical purposes,
but the invention is not limited to that form of switch, as other switches may also
be employed for the purpose if desired, and the parts i i may be placed in one or
more straight rows instead of in the arc form without departing from this
invention.
By the employment of this invention, there is great saving in metal and frame
work, and a rheostat is produced which is much lighter, cheaper and better adapted

page_text: to nice graduations of current than any which have heretofore been devised so
far as is known.
In the example of this invention shown in Figures 1 and 2 of the drawings,
the strips have been lettered b c d e f g h and the parts shown broken across
to emphasize the fact that the strips need not be extended in a straight line of
the length of resistance required, but may be folded upon themselves in any manner
desired. Furthermore the strips may be covered with or enclosed in any suitable
material such as is well known in the art, and while my correspondents have shown
and described strips they desire to say that they do not limit themselves to that form,
but that wires may also be employed if desired, and a greater or smaller number
of resistances than shown may be employed, and also more than one fractional
resistance 6 may be employed, depending upon the number and character of
graduations desired.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is:-
In a rheostat, a suitable supporting frame, end pieces, and two bars which con-
nect the pieces together, a metallic strip secured to the upper end piece, and to
which is attached a binding post; and the resistance strips combined with suit-
able contact parts to which the ends of the resistance strips are secured, but which
contact parts are electrically separated from each other, the binding post as j
and the connecting strip as k connected to the post, and a switch which has its
edge to pass under the ends of the contact parts, substantially as described.
Dated this Zorn day of April 1030.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents.