IMPROVEMENTS IN RAILWAY CHAIRS
Year: 1877

page_text: LETTERS PATENT to William Black and James Graham Tatters, both of-South
Shields, in the County of Durham, for the Invention of "IMPROVEMENTS IN
RAILWAY CHAIRS."
Sealed the 4th January 1878, and dated the 11th July 1877.
PROVISIONAL SPECIFICATION left by the said William Black and James
Graham Tatters at the Office of the Commissioners of Patents on the 11th
July 1877.
WILLIAM BLACK and JAMES GRAHAM TATTERS, both of South Shields, in-the
County of Durham. "IMPROVEMENTS IN RAILWAY CHAIRS."
Our Invention relates to an improved form of railway chair, whereby the wooden
wedges or keys, which are used to secure the rails in the chairs, are prevented from
falling out.
In carrying out our Invention in order to secure the wooden wedges or key's
from falling out, we provide the chair with teeth of a semi-pyramidal : form
placed in vertical lines on the inner side of the jaw of the chair facing the
wooden wedge or key, the jaw facing the rail, remaining smooth as heretofore.
Where the chair consists of cast iron, it is only necessary that the pattern should
be made with the requisite number of teeth on the inner side of the jaw with which
the wooden wedge or key is to be brought into contact.
The advantage of our improved railway chair over those hitherto in use consists
in the better maintaining of the wedge or key in its proper position, as in the old
forms it is found that the wedge or key, by alternate pressures and shakings, assisted
by the shrinkage of the wood of which it is composed, is liable to become loose and
fall out, tending to leave the rail insecure;. whereas the form of our improved rail-
way chair renders it impossible for the wedge or key to fall out, as the pressure
through the rail from the rolling stock passing over it tends to act in an
opposite direction, as each intermittent pressure received drives the wedge
or key into the teeth until all are quite filled, when it will be found that
no subsequent amount of shaking, jolting, or shrinkage can cause it to
fall out.
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Black and James Graham Tatters in the Great Seal Patent
Office on the 10th January 1878.
WILLIAM BLACK and JAMES GRAHAM TATTERS, both of South Shields, in the
County of Durham. "IMPROVEMENTS IN RAILWAY CHAIRS."
Our said Invention relates to improvements in railway chairs, whereby the
danger, trouble, and expense attending the use of wooden wedges or keys when
employed in combination with chairs of the ordinary construction are entirely
obviated.
In the use of wooden wedges or keys for fastening the rails of railways in their
chair, it is found that such wedges or keeps become loose, and in many cases fall
out of the chairs, thus rendering the permanent way insecure, and endangering the
safety of trains running over it.
In order to obviate this danger it is found necessary to employ men to examine
daily the condition of the wedges or keys throughout the whole extent of the line,
replacing those which have dropped out, and tightening the loose ones, which
operations entail considerable trouble and expense.
Now, our said Invention has for its object the removal of the source of danger
before mentioned, and avoiding its attendant trouble and expense by con-
structing the chair of such a form that the wedge or key when once properly
placed between the rail and the chair will continue to remain there without
any liability of dropping out until removed by the application of force for that
purpose.
In carrying out our said Invention in order to effect this object we cast or form
the chair (which is or may be otherwise similar to the pattern in ordinary use) with
two or more rows of semi-pyramidal teeth upon its outer jaw, arranged in such a
manner that on the wedge or key being driven in between the rail and chair, such
semi-pyramidal teeth will sink into the wedge or key, and thus support and main-
tain it in its place, so that no amount of shaking or jolting can cause it to become
loose and drop out.
And in order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of our Drawings represents a longitudinal section of a chair constructed
according to our said Invention, with the position of the rail and wedge or key
indicated by dotted lines.
Figure 2 is a sectional elevation of the chair, the view being taken at right angles
to Figure 1.
And Figures 3 and 4 are longitudinal sections of the toothed portion taken
respectively along the lines 1, 2, and 3, 4, Figure 2.
A is the chair, and B is the rail, the latter resting upon the bottom a of the chair,
Bupported by the inner jaw b, and secured by a wooden wedge or key C, driven in
between the rail B and the outer jaw c in the usual manner. The outer jaw c,
however, in lieu of being made plain, is cast or otherwise formed with a suitable
number of semi-pyramidal teeth d, d, arranged in vertical and horizontal rows, as
shewn clearly in Figure 2; 1 being the apex of each pyramid through which it may
be assumed to have been divided; 2, 3, one side of the pyramid; 2, 4, one half side;
and 3, 5, the other half side.
The wedge or key C is driven in the direction of the arrow, Figure 2, and, as it
enters the chair, it first meets the sides 2, 3, of the pyramids of the first vertical row,
and then as it advances it is acted upon by the sloping sides 2, 1, 3, 1, until finally
the apices 1 are arrived at, when the fibres of the wood will close up behind the
semi-pyramids, the wedge or key is then acted upon by the semi-pyramids of the
pext vertical row, and so on in succession until-it is forced into its place. It will

page_text: thus be seen that whilst no obstruction is offered to the entrance of the wedge or
key a direct end force is requisite to effect its withdrawal, and moreover that
the greater the lateral pressure the firmer are the teeth pressed into the wedge
or key, so that the heavier the traffic of rolling stock over such secured wedges
or keys the more firmly are they secured to their places in the chairs; whereas
with chairs of the ordinary construction it is found that as the traffic increases
the danger of the wedge or key falling out is augmented as each distinct lateral
pressure tends to squeeze and make thinner the wedge, thus causing it to become
loose, and if not tightened up in time eventually to drop out.
The number and size of the semi-pyramidal teeth employed will vary according
to the dimensions of the chair used, but the arrangement and proportions
shewn in our Drawings are given as an example which has been found suitable
in practise.
Having now described and particularly ascertained the nature of our said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
we would observe in conclusion that what we consider to be novel and original,
and therefore clain as the Invention secured to us by the herein-before in part
recited Letters Patent is,-
The application to railway chairs of teeth of a semi-pyramidal form, substantially
in the manner and for the purpose herein-before described.
In witness whereof, I, the said James Graham Tatters, on behalf of myself and
the said William Black, have to this our Specification set my hand and seal,
this Ninth day of January, One thousand eight hundred and seventy-eight.