Improvements in Clamp Connections for Electrical Conductors.
Year: 1897

page_text: Date of Application, 9th Feb., 1897-Accepted, 27th Mar., 1897
COMPLETE SPECIFICATION.
Improvements in Clamp Connections for Electrical Conductors.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of London, Electrical Engineers, do hereby declare
the nature of this invention (as communicated to us from abroad by Siemens &
Halske, of Berlin in the German Empire, Electrical Engineers,) and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates to an improved construction of clamp connection for
electrical conductors whereby branch conductors can be reliably and readily
connected to a continuous main conductor or generally two conductors can he
effectually connected together. The essential feature of the invention consists in
so arranging the parts constituting the clamp-connection that by means of a single
screw the main conductor and the branch are each independently connected to the
clamp with a considerable amount of contact surfaces that are pressed together
by the full force exerted by the screw, without requiring any special preparation
of the main conductor for this purpose, while the branch conductor has its end
either bent into a loop or eye, or has a connecting shoe secured thereto.
On the accompanying drawings are shewn three constructions of connecting
clamps according to this invention.
In the construction shewn at Fig. 1, the clamp consists of three parts, namely
the two cranked members, a and b and the screw c which passes freely through a
hole in b and screws into a threaded hole in a. The parts a and b have saddle-
shaped ends which fit respectively against opposite sides of the main conductor d
which in this case is assumed to be a wire cable, while the branch conductor has a
shoe e fixed on it which is fitted under the head of the screw c. Thus it will be
seen that on tightening up the latter, on the one hand, the conductor d is firmly
clamped between the saddles of a and b, while at the same time the shoe e of the
branch conductor is firmly clamped between the head of c and the top of b.
For the purpose of enabling the clamp to be made as compact as possible and.
with a minimum amount of metal, while affording the necessary strength, it is
preferred to employ a looped form for the members instead of the cranked form
shewn at Fig. 1, in which case in order to enable the one member of the clamp to
be fitted on the continuous conductor from the side, it is necessary to make the
member a of two separate parts.
Figs. 2 to 6 shew two modifications of such a construction, in both of which the
parts a and b are assumed to be stamped out of sheet metal.
In the construction shewn in cross section at Fig. 2 and side view at Fig. 3, the
part a is bent into loop form, having its ends bent over to form hooks, and at the
sides portions are bulged inward by stamping, so as to form projections between
which and the booked ends is slid laterally a plate a' after the loop a has been
fitted on the conductor; this plate or nut has a threaded hole for the reception of
The part is also bent into looped form, so as to constitute a bridge
piece extending longitudinally over a a¹, and bearing with its hollowed ends upon
top part of the couductor d. On passing the screw c through the shoe e of the
branch conductor and through the part b, and screwing it up in the plate a', the
conductor will be firmly clamped between a and b, aud e will be secured between
the screw head and the part b.
the screw c.

page_text: In the modified constructions shewn respectively in cross section, side view and
longitudinal section at Figs. 4, 5 and 6, the part a has slots punched into it, into
which project the ends of the T head of the bolt c, the threaded stem of which
projects up through the part 6 and loop of conductor e, and is secured by a nut c¹.
The part 6 in this case may have additional side flaps b¹ that fit over the ends of a
and thus hold them together.
In the above arrangements, in order to prevent any detrimental shearing action
of the clamp upon the conductor d, either the part is widened at bottom so as to
project under the part which bears the pressure of member b, as at Fig. 3, or the
member has its ends bent inwards as at Fig. 6 so as to be situated within the
part a.
Although we have spoken of d as being the main conductor and e the branch
conductor, it will be obvious that their functions may be reversed, or the clamp
may be employed for connecting two parts of a main conductor.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, we declare that what we
claim is
1. A clamp connection for electrical conductors consisting of the combination of
two separate members such as a and b so connected by a screw passing loose
through the one member and screwing into the other that on tightening the screw
the two members are made to approach each other so as to be adapted to grip the
one conductor inserted between them, while a second conductor can at the same
time be gripped between the head or nut of the screw and the members through
which it passes freely, substantially as described.
2. In a clamp connection such as is referred to in the first claim, constructing the
two members a and b as cranked pieces arranged substantially as described with
reference to Fig. 1 of the drawings.
3. In a clamp connection such as is referred to in the first claim, the combination
of a looped member a carrying a separate screw nut a¹ and adapted to receive the
one conductor within it, a second looped member 6 the ends of which are adapted
to grip the conductor between it and the member a, and a screw c passing loose
through the member and screwing into the nut a', and adapted to grip the second
conductor between its head and the member b, substantially as described with
reference to Figs. 2 and 3.
4. In a clamp connection such as is referred to in the third claim, the modified
construction wherein the screw c engages with a T head in notches in the one
member a and carries a screw nut c¹ above the other member, substantially as
described with reference to Figs. 4, 5 and 6.
Dated this 9th day of Februan. 1907
ABEL & IMRAY,
Agents for the Applicants.