IMPROVED MEANS OF CONSTRUCTING AND ATTACHING TENSION BARS
Year: 1879

page_text: LETTERS PATENT to Charles William Siemens, of No. 12, Queen Anne's Gate,
Westminster, in the County of Middlesex, for the Invention of "IMPROVED
MEANS OF CONSTRUCTING AND ATTACHING TENSION BARS."
Sealed the 6th January 1880, and dated the 8th July 1879.
PROVISIONAL SPECIFICATION left by the said Charles William Sicinens at
the Office of the Commissioners of Patents on the 8th July 1879.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVED MEANS OF CONSTRUCTING AND ATTACHING
TENSION BARS."
In constructing bridges and other great engineering works, it is often necessary
to make long tension bars in a number of separate lengths joined together, or to
joint tension bars to heads or ends of special form for fixing or attachment. My
Invention relates to means of joining such lengths of bars to one another, or to the
attaching heads or ends in such a manner, as to avoid loss of strength by inter-
ruption of the sectional continuity, as in cases where rivets, bolts, or such like
means of fixing are employed. I make the ends of the bar or bars and heads that
are to be joined with shoulders projecting on each side, these shoulders being
preferably undercut with an inward dovetail slope, and I secure those ends together
by means of two side-covers which are dovetail slotted along their middles to fit
the shoulders of the bars. In order to set the bar shoulders home and give them a
firm bearing in the slots of the side covers, I drive a key or wedge between the
ends of the bars which are made slightly sloped to receive such key or wedge. The
parts of the bars immediately behind the shoulders are made somewhat thicker
than the bar itself, the additional thickness being made by a gradual taper so as to
avoid abrupt change of section in any part, except at the shoulders where the bar
has an area increased by the amount of taper. To provide against lateral shifting
of the parts, a cover plate may be fixed on each face of the joint. The side covers
are with advantage made of semicircular form externally, so that they have a con-
siderable sectional area at their middles. As above described, they are held in
their places bound against the bars by the dovetail form of the shoulders, they may
however be secured by cross bolts passing through between the ends of the bars
from side to side. The bars to be jointed as above described being rolled as plain
bars of the desired section, have their ends prepared for jointing by heating and
upsetting them while they are clamped in a mould or vice of suitable form to
provide for the taper and shoulders. The side covers may be made as bars rolled
to the required section, and cut to the desired lengths. The fitting surfaces of the
bar ends and side covers are preferably planed.

page_text: TENSION BARS:"
In constructing bridges and other great engineering works, it is often necessary
to make long tension bars in a number of separate lengths joined together, or to
joint tension bars to heads or ends of special form for fixing or attachment. My
Invention relates to means of joining such lengths of bars to one another, or to the
attaching heads or ends in such a manner, as to avoid loss of strength by inter-
ruption of the sectional continuity, as in cases where rivets, bolts, or such like
means of fixing are employed. I make the ends of the bar or bars and heads that
are to be joined with shoulders projecting on each side, these shoulders being pre-
ferably undercut with an inward dovetail slope, and I secure those ends together
by means of two side covers which are dovetail slotted along their middles to fit
the shoulders of the bars. In order to set the bar shoulders home and give them a
firm bearing in the slots of the side covers, I drive a key or wedge between the
ends of the bars which are made slightly sloped to receive such key or wedge. The
parts of the bars immediately behind the shoulders are made somewhat thicker than
the bar itself, the additional thickness being made by a gradual taper so as to
avoid abrupt change of section in any part, except at the shoulders where the bar
has an area increased by the amount of taper. To provide against lateral shifting
of the parts, a cover plate may be fixed on each face of the joint. The side covers
are with advantage made of semicircular form externally, so that they have a con-
siderable sectional area at their middles. As above described, they are held in their
places bound against the bars by the dovetail form of the shoulders, they may
however be secured by cross bolts passing through between the ends of the bars
from side to side. The bars to be jointed as above described being rolled as plain
bars of the desired section, have their ends prepared for jointing by heating and
upsetting them while they are clamped in a mould or vice of suitable form to
provide for the taper and shoulders. The side covers may be made as bars rolled
to the required section and cut to the desired lengths. The. fitting surfaces of the
bar ends and side covers are preferably planed.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a side elevation; Fig. 2, a longitudinal section; and Fig. 3, an edge 'view
shewing-the-junction-according-to-my-Invention-of-a-bar-A-to-a-link, or it might
be another length of bar B. The ends of A and B are upset so as to have their
thickness somewhat increased at a and b, and to have formed on them dovetail
shoulders c. These shoulders fit into corresponding chases formed in two side
covers D, D, and are seated firmly therein by a taper key E driven between the
ends of the bars which are slightly sloped to fit the key. In order to prevent the
side covers or the bars from shifting laterally, covering washers F may be fixed by
screws or studs on the ends of the joint, and these washers may either have through
them rectangular holes as shewn, giving free passage for driving the key E after
the washers have been put on, or they might be made without such holes, and put
on after driving the key. The key E and covering washers F might be dispensed
with, the side covers D, D, being secured by bolts and nuts G as shewn in the side
view, Fig. 4, and longitudinal section, Fig. 5.
Having thus described the nature of the said Invention, and in what manner
the same is to be performed,

page_text: 1 claim,
First. Attaching tension bars or joining lengths thereof by forming their ends
with projecting dovetail shoulders on each side, and engaging these shoulders firmly
in corresponding shoulders formed in two side covers, substantially as herein
described.
Second. The construction of joint for tension bars herein described with reference
to the accompanying Drawings.
In witness whereof, I, the said Charles William Siemens, have hereunto set
my hand and seal, this Sixteenth day of December, in the year of our Lord
One thousand eight hundred and seventy nine.
C. WILLIAM SIEMENS. (L.S.)