Improvements in the Method of and Apparatus for Making Electrical Connections.
Year: 1891

page_text: Date of Application, 8th July, 1891
Complete Specification Left, 8th Apr., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Method of and Apparatus for Making Electrical
Connections.
I, JOHN HENRY HOLMES, of Portland Road, Newcastle-on-Tyne, in the
County of Northumberland, Electrical Engineer, do hereby declare the nature of
this invention to be as follows :-
This invention has for its object the simplification of apparatus made for con-
necting together electrical conductors and at the same time providing good contact
surfaces and ensuring the requisite pressure between these surfaces and their
certainty of action.
The principle of my invention consists in the use of the circular wedge. This
can be carried out in practice in several different ways. First, where two nearly
concentric conductors have to be connected, these latter are made with cylindrical
surfaces, but eccentric somewhat with each other. A cylindrical plug, having a
cylindrical hole therein nicely fitting the internal cylinder but eccentric to the
exterior cylindrical surface of the said plug, is used as a connector. The plug is
inserted round the internal conductor inside the external conductor, forming a
loose fit with the latter, when the axes of eccentricity coincide. By turning the
plug round however, the thicker portion of the plug enters the thinner portion of
the space between the internal and the external conductors until it is wedged
tight. The plug can be formed of an inside and an outside cylinder insulated
from each other and each connected with a line wire; in this way a series of
lengths of two wires forming a complete circuit can be coupled up. This would
be especially useful in electric appliances on railway trains which require to be
coupled up quickly and securely. Where the plug itself is a terminal and has to
form contact with another conductor, the plug is preferably formed cylindrically
with a projecting smaller cylinder at its end, the axis of which is not quite in a line
with the axis of the larger cylinder. In the other conductor, a cylindrical hole,
loosely fitting the wider portion of the plug, is formed, and another cylindrical hole,
somewhat eccentric with this, is formed at the extremity of the first, loosely fitting
the smaller diameter of the plug. The plug is then inserted in this case again,
when the eccentricity of the plug coincides in direction with the axes of the two
holes, the plug can enter these holes freely. If, however, the plug be turned round
till the diametric line passing through the two axes of the plug ceases to coincide
with a similar line in the two holes and the motion be continued, the plug quickly
wedges tight in the holes. Similarly, two electric mains in this manner can be
Bocketted one into another, one end of the inside main forming an eccentric fitting
loosely a cylindrical hole in the end of the other inside main, and one end of the
outside main forming a socket into which the other outside main enters and is
tightened by either the tension caused by the eccontric and the inside main, or by
its own eccentricity or both. In this way, also, three, four or any number of
concentric mains can be coupled. Terminals or binding screws can also be fixed
in this manner and in fact almost all forms of electric connections can be thus
made.
I have herein given a few applications of the principle of a circular wedge for
contact making, but it is obvious that other forms and mechanism can be used, whereby
a conductor or conductors with or without a plug or its equivalent can be employed
to firmly wedge or supply contact pressure and thus couple up two conductors or
two pairs or two sets of conductors by turning one of them or a plug round, further,
that the cylindrical or even circular form is not absolutely necessary, as it is obvious
that a skeleton of two or more arms or a segment of a circle can take the place of

page_text: a complete circle, also that, if longitudinal motion be provided against, conical
devices can take the place of cylindrical ones.
Dated this 7th day of July 1891.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for Making Electrical
Connections.
I, JOHN HENRY HOLMES of Portland Road, Newcastle-on-Tyne in the County
of Northumberland, Electrical Engineer, do hereby declare the nature of this inven-
tion and in' what manner the same is to be perforined, to be particularly described
and ascertained in and by the following statement :-
This invention has for its object the simplification of apparatus made for
connecting together electrical conductors and at the same time providing good
contact surfaces and ensuring the requisite pressure between these surfaces and
their certainty of action.
"
The principle of my invention consists in the use of the circular wedge. This
can be carried out in practice in several different ways, and is best described by aid
of the accompanying drawings, in which :-
Figure 1
Figure 2.section of same;
the plan view of one half of a coupling device;
Figure 3 plan of the other half;
Figure 4 section of same;
Figure 5 plan of plug used instead of the apparatus set forth in Figure 3 when it
is desired simply to connect up the two conductors ;
Figure 6 section of same;
Figures 7 and 9 plan views of the two parts of a device to join up cables;
Figures 8 and 10 longitudinal sections of same;
.
Figures 11 and 13 plan views of an arrangement for coupling two pieces of
concentrically grouped conductors ;
Figures 12 and 14 transverse sections of same;
Figures 15 and 16 two parts of a coupling for a single line.
Referring to Figures 1 to 6 inclusive:-
An apparatus where two nearly concentric conductors A and B are to be
'connected-
These latter are made with cylindrical surfaces, but eccentric somewhat with
each other. A cylindrical plug C, having a cylindrical hole therein nicely fitting
the internal cylinder, but eccentric to the exterior cylindrical surface of the said
plug, is used as a connector. The plug is inserted round the internal conductor
inside the external conductor, forming a loose fit with the latter when the axes of
eccentricity coincide. By turning the plug round, however, the thicker portion of
the plug enters the thinuer portion of the space between the internal and the
external conductors, until it is wedged tight. Where, however, these two conductors
are to be rapidly and securely connected to two line wires, the arrangement set
forth in Figures 3 and 4 is used.
The plug is formed of an inside conducting cylinder D and an outside one E,
insulated from each other and each connected with a line wire FF; in this way, a
series of lengths of two wires forming a complete circuit can be coupled up. This
would be especially useful in electric appliances on railway trains which require to
be coupled up quickly and securely. Where the plug itself is a terminal and has
to form contact with another conductor, the plug, shown, in Figure 7, is preferably
used
it is formed cylindrically with a projecting smaller cylinder G at its end, the
axis of which is not quite in a line with the axis of the larger cylinder H. In the
1

page_text: other conductor, Figure 8, a cylindrical hole I, loosely fitting the wider portion H
of the plug, is formed, and another cylindrical hole J, somewhat eccentric with this,
is formed at the extremity of the first, loosely fitting the smaller diameter of the
plug G. The plug G H is inserted into the hole IJ. When the eccentricity of
the plug coincides in direction with the axes of the two holes, the plug can enter
these holes freely. If, however, the plug be turned round till the diametric line,
passing through the two axes of the plug, ceases to coincide with a similar line in
the two holes and the motion be continued, the plug quickly wedges tight in the
holes. Similarly, two electric mains in this manner can be socketted one into
another, as set forth in Figures 9 to 12 inclusive, one end of the inside main, A,
forming an eccentric fitting loosely a cylindrical hole in the end of the other
inside main, and one end of the outside main I forming a socket B into which the
other outside main H of Figure 10 enters and is tightened by either the tension
caused by the eccentric and the inside.main, or by its own eccentricity, or both. In
this way, also three, see Figures 13 to 16, four, or any number of concentric
mains NH G can be coupled to similar mains M L J.
I have herein given a few applications of the principle of a circular wedge for
contact-making, but it is obvious that other forms and mechanism can be used
whereby a conductor or conductors, with or without a plug or its equivalent, can
be employed to firmly wedge or supply contact pressure and thus couple up two
conductors or two pairs or two sets of conductors by turning one of them or a plug
round; further, that the cylindrical or even circular form is not absolutely
necessary; as it is obvious that a skeleton of two or more arms or a segment of a
circle can take the place of a complete circle, also that, if longitudinal motion be
provided against, conical devices can take the place of cylindrical ones.
,
Having now particularly described and ascertained the nature of my said inven
tion and in what manner the same is to be performed, I declare that I am well
aware that a bayonet joint or other circular wedge or inclined plane has been used
in bottles and bottle stoppers to hold the latter securely in the former, also that it
is no uncommon device, in mechanics, to hold, stop or prevent further motion in a
falling or moving body by the use of an eccentric wedge or cam, also that, in
electric switchos, cranks have been forced against a plane inclined slightly to the
circle of rotation in order to jam the said crauk, and I make no claim for such, but
that what I claim is :-
An electric coupling device formed of two or more cylinders (or their equivalent.
as described) having parallel axes slightly eccentric to each other, in combination
with two or more sockets slightly eccentric to each other and so designed that,
when the two eccentricities coincide in direction, the cylinders can freely enter the
sockets but the said cylinders shall tightly jam in the said sockets when they are
rotated on their axes relatively to the sockets.