Year: 1886

page_text: Date of Application, 17th Apr.; 1886..
Complete Left, 17th Jan., 1887.
Complete Accepted, 18th Feb., 1887.
I, ACHILLES DE KHOTINSKY, of Rotterdam Oost. Maaskade, 67, Electrician do
hereby declare the nature of this invention to be as follows:-
In apparatus for making or breaking electrical contact, such as switches or cut-offs,
it is usual for effecting contact to make one metallic surface press or rúb upon another,
these surfaces being made of suitable area to give passage for the current with little
resistance. It is difficult in the first instance to make such surfaces fit each other with
accuracy, and after moderate use the surfaces become so much impaired by friction
sparking that contact is very imperfect..
My invention relates to a construction of such apparatus whereby, within given
dimensions and ranges of movement, I am enabled largely to increase the extent of
surface contact, and by simple multiplication of parts to adapt for passage of a large
current a switch or cut-off originally suited for a small current. For this purpose I
subdivide the two sets of metal pieces that are to make contact into several plates or
thicknesses, spacing these apart, so that the plates of the one piece enter the spaces between
the plates of the other piece, both sides of each plate thus constituting contact surfaces
which may be multiplied to any desired extent by multiplying the number of plates
used to constitute each piece. Thus in a simple switch for diverting an electrical
current from one conductor to another, I mount on a fulcrum pin a lever consisting of
an insulating handle carrying two or more strips of metal which are superposed at a
little distance apart. On the frame which carries the fulcrum and insulated from it I
fix two other sets of metal strips, each consisting of three or more strips superposed at
intervals. The fulcrum and its lever being in metallic connection with a main
conductor while each of the iwo sets of fixed strips is in connection with another
conductor, on moving the lever to the one side or the other the strips of which it
consists are made to enter the spaces between the strips of either of the fixed sets, thus
making extended contact by which the current passes from the main conductor to
either of the others. When the lever is in a middle position contact is broken. In
like manner for a reversing switch two levers each consisting of superposed strips may
be used in conjunction with three sets of fixed strips both levers being moved simul-
taneously by one handle which may be linked or geared to them. And similarly a
lever or levers consisting of superposed strips may be moved to make or break contact
with a number of different sets of strips in order to introduce, or cut out various leads
or resistances. -
ABEL & IMRAY,
28, Southampton Buildings, London, W.C.,
Agents for the Applicant."

page_text: '
I, ACHILLES DE KHOTINSKY of Rotterdam Oost Maaskade, 67, Electrician 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 following statement :-
In apparatus for making or breaking electrical contact, such as switches or cut-offs,
it is usual for effecting contact to make one metallic surface press or rub upon another,
these surfaces being made of suitable area to give passage for the current with little
resistance. It is difficult in the first instance to make such surfaces fit each other with
accuracy, and after moderate use the surfaces become so much impaired by friction
and sparking that contact is very imperfect.
My invention relates to a construction of such apparatus whereby, within given
dimensions and ranges of movement, I am enabled largely to increase the extent of
surface contact, and by simple multiplication of parts to adapt for passage of a large
current a switch or cut-off originally suited for a small current.
For this purpose
subdivide the two sets of metal pieces that are to make contact into several plates or
thicknesses, spacing these apart, so that the plates of the one piece enter the spaces
between the plates of the other piece, both sides of each plate thus constituting contact.
surfaces, which may be multiplied to any desired extent by multiplying the number of
plates used to constitute each piece. Thus in a simple switch for diverting an electrical
current from one conductor to another, I mount on a fulcrum pin a lever consisting of
an insulating handle carrying two or more strips of metal which are superposed at a
little distance apart. On the frame which carries the fulcrum, and insulated from it,
I fix two other sets of metal strips, each consisting of three or more strips superposed
at intervals. The fulcrum and its lever being in metallic connection with a main
conductor while each of the two sets of fixed strips is in connection with another
conductor, on moving the lever to the one side or the other, the strips of which it
consists are made to enter the spaces between the strips of either of the fixed sets, thus
making extended contact by which the current passes from the main conductor to
either of the others. When the lever is in a middle position contact is broken. In
like manner, for a reversing switch, two levers each consisting of superposed strips
may be used in conjunction with three sets of fixed strips, both levers being moved
simultaneously by one handle which may be linked or geared to them. And similarly,
"a lever or levers consisting of superposed strips may be moved to make or break contact
with a number of different sets of strips, in order to introduce or cut out various leads
or resistances. Figs. 1, 2 and 3 of the accompanying drawings illustrate diagramma-
tically my invention which I may farther explain with reference to these figures: A and B
Fig. 1 being two metal plates in contact over a surface Q which may be of the same
area as the sectional area of A or B, if the contact at Q were mathematically perfect
the conduction from the one plate to the other would be as complete at Q as the
conduction through the body of either plate. As, however, there is no such thing as
'

page_text: perfect contact in any such case, it is necessary to provide an extended surface of
contact to give sufficient conductivity at the meeting of the two conductors. By
dividing each of the plates A and B into two thicknesses as shewn by Fig. 2, I obtain
three surfaces of contact each as large as the one surface in Fig. 1. Or again, by sub-
dividing the plates into four thicknesses as indicated by Fig. 3, I obtain seven contact
surfaces instead of one. Such subdivision diminishes electrical resistance, not only by
affording a greater number of contact surfaces, but also by rendering the contact of
cach pair more perfect by reason of the electricity of the thinner plates, and their
flexibility allowing them to accommodate themselves to such uneven portions of their
respective surfaces as may present themselves. Thus, for example, if the plate A Fig. 1
had to conduct a current of 100 Ampères it might be divided into 50 plates each taking
2 Ampères, the passage of current at each pair of contact surfaces being thus reduced
to any extent desired.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :
In electrical contact apparatus subdividing the conductors which are brought in
contact into several thicknesses so as to multiply the contact, surfaces, substantially as
and for the purposes set forth.
ABEL & IMRAY,
Agents for the Applicant.