CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF RAILWAY CHAIRS
Year: 1871

page_text: LETTERS PATENT to John Lidderd, of Manchester, in the County of
Lancaster, Mechanic, for the Invention of "CERTAIN IMPROVEMENTS IN
THE CONSTRUCTION OF RAILWAY CHAIRS."
COMPLETE SPECIFICATION filed by the said John Lidderd at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 30th June 1871, pursuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LIDDERD, of Manchester, in the County of Lancaster, Mechanic, send
greeting.
WHEREAS I am in possession of an Invention for "CERTAIN IMPROVE-
MENTS IN THE CONSTRUCTION OF RAILWAY CHAIRS," and have petitioned Her
Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and have made solemn Declaration
that I am the first and truc Inventor thereof.

page_text: NOW KNOW YE, that I, the said John Lidderd, do hereby declare
that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and in
what manner the same is to be performed, in and by the following
statement and accompanying Drawings, that is to say:―
My Invention is designed for the purpose of so constructing a railway
chair that it can be readily adapted to the metals it is designed to support
and grip, and also by its peculiar construction enabling it firmly to
maintain its hold upon the rails or metals without the use of wooden
wedges, as ordinarily employed.
As the principle of the Invention embraces various methods of
construction I will proceed to describe them. The improvements consist
in constructing the jaws composing the chair in two parts and joining
them together underneath the rails or metals, the peculiar coupling
together of the two jaws or parts of the chair being the feature of the
Invention.
I will proceed to describe them under their several heads, and in
what their various modifications consist. The rail or metal is supported
by the improved chairs in a position that will not admit of any contact
between the bottom surface of the rail and the base plate of the chairs,
thus avoiding abrasion and inequality or indentations to the said under
surfaces.
The first arrangement of the chair according to the improved con-
struction I make in two parts, each of which contains one jaw. The
portion of the chair containing the outer jaw is provided with a base
plate that also supports the inner jaw. The said inner jaw for this
purpose is constructed with a base that will admit of its sliding within
a dovetailed groove formed in the upper surface of the base plate of the
outer jaw. The said inner jaw when fully forced up in its groove against
the rail is firmly secured there by means of a metal key or wedge that
is forced into and through a wedged form hole in part of the base of the
chair corresponding to the position the sliding jaw thereof will assume
when the face of the same is in contact with the rail, sufficient clearance
or back lash being provided in the said hole that will admit of the jaws
being firmly brought together into contact with the rail as the wedged
key is driven home, the whole being firmly secured by "progs" or nails
to the sleeper, or in lieu of the wedged key a prog or nail may be
employed having a taper surface.

page_text: A second construction of chair according to these present improvements
consists in casting the halves in duplicate, with this exception, that the
surfaces coming together underneath the rail are formed so that a recess
in one will admit of a corresponding projection in the other to fit therein,
the two being then permanently coupled and drawn together by means
of a wedged metal key which is driven through a hole formed for its
reception underneath and parallel with the rail. The driving up of the
metal wedge brings the jaws of the chair into contact with the rail, so as
firmly to support and retain the same.
According to the third arrangement of chair forming a part of these
improvements the two parts composing the chair are joined together
underneath the [rails or metals. The inner terminals in this case fit
into each other so as to form a common joint through which a pin is
passed, thus forming the coupling or connection between the two halves
of the chair, the peculiarity of such coupling joint being so arranged
that when the chair is in its position upon and secured to the sleeper
supporting the rail the junction of the two halves thereof will bear upon
such sleeper with less pressure than at those points, the greatest distance
from the centre or joint thus allowing the jaws when merely supporting
the rail to give a minimum amount of pressure against such rail, but
when sustaining the weight or pressure of a passing train the yielding
of the centre joint will cause the jaws to bear with their greatest pressure
against the rail, thereby giving a firm and steady grip thereto; or
according to another arrangement the duplicate parts of the chair may
be provided with ears or lugs projecting from either side the chair
underneath the rail, which when placed upon the sleeper on their
respective sides of the rail and brought into contact therewith are secured
permanently together by bolts and nuts or other equivalent.
In order that the Invention may be better understood and explained
in detail, I have hereunto attached a Sheet of Drawings made to a
scale of about half the usual size, similar letters of reference being
marked on corresponding parts on all the Figures alike.
Fig. 1 represents a front and Fig. 2 a side elevation of the improved
construction of railway chair in which a sliding dovetailed key jaw is
shewn; Fig. 3 represents a side and Fig. 4 an under plan view of another
modification of chair in which the duplicate halves of the chair are
drawn and secured together underneath the rail by means of a wedged
key; Fig. 5 represents a side elevation of the chair shewing the duplicate

page_text: halves thereof hinged so as to form a "joint" connection underneath
the rail, and Fig. 6 represents a side and Fig. 7 a plan view of the
duplicate halves connected together by bolts and nuts passing through
projecting ears or lugs on either side the chair underneath the rail.
In these Figures a, a', represent the two parts or duplicate halves of
the chair, and the rail or metal. In Figs. 1 and 2 the jaw a is pro-
vided with a projecting base plate e which passes underneath the rail b,
and on which is a dovetailed groove or channel constructed to receive the
sliding dovetailed base of the inner jaw a'; this jaw a when fully forced
up in its groove against the rail is firmly secured there by means of
the horizontal taper metal key d or by the prog e which is forced through
a slot in the base plates of the jaws into the sleeper, the inner side of the
said prog or nail being slightly tapered so as to give a pressure tọ
the sliding jaw in a direction against the rail, as seen in diagram e', the
permanent securing of the chair to the sleeper being effected in the usual
manner by progs or nails.
In Figs. 3 and 4 it will be seen that the junction of the duplicate
halves of the chair a, a', are effected by means of a rappit joint, through
the horizontal centre of which underneath the rail the wedged key d is
forced, bringing thereby the duplicate parts of the chair into firm and
steady contact with the rail b.
In Fig. 5 the junction of the duplicate jaws underneath the rail is
effected in the manner of an ordinary hinge or joint f. The jaws when
thus coupled in contact with and merely supporting the rail bear with
a less pressure on the sleeper at the joint than at the termination of
their base plates, thus allowing when sustaining the weight of a passing
train a slight yield under the centre of pressure that forces at such time
the jaws into close and firm contact with the rail or metal they are
designed to hold.
Finally, in Figs. 6 and 7 the duplicate halves of the chair at their
surfaces of junction underneath the rail are provided with projecting
cars or lugs g, g, on either side provided with holes through which the
bolts h, h, are passed for the purpose of firmly securing the said halves
of the chair together. The said surfaces of junction at an intermediate
position on their surfaces of contact are provided with a projection and
recess i which fitting together prevents any undue or over straining of
the bolts and nuts h, h. The peculiar construction and adaptation of

page_text: such sliding or duplicate jointed chairs employed for the purpose of
supporting the rails or metals of railways readily allows any one of the
same to be removed from its supporting sleeper and another replaced
without disturbing the rest of the chairs in contact with the rail.
Having now described the nature of the said Invention, together with
the method of carrying the same into practical effect, I would wish it
to be distinctly understood in conclusion that although I have shewn
various arrangements and modifications of the application, construction,
and adaptation of my improvements I do not wish to confine myself to
the precise details herein shewn and described so long as the essential
features of the Invention are retained, and which are embodied in the
following claims, viz.,―
2
First. I claim the novel and peculiar construction and adaptation of a
dovetailed sliding jaw sliding on the base of the outer jaw, both being
secured together so as to form a whole in contact with the rail by means
of wedged nails or cottars in the manner and for the purpose described
and set forth.
Secondly. I claim the, novel and peculiar construction, adaptation,
and arrangement of railway chair in duplicate halves and joining them
together underneath the longitudinal centre of the rail by means of
wedges, bolts, or other equivalent in the manner and for the purpose
described and set forth and fully illustrated in the Drawings attached, or
any further slight modification thereof.
In witness whereof, I have hereunto set my hand and seal, this
Twenty-eighth day of June, in the year of our Lord One
thousand eight hundred and seventy-one.
Witness,
W WALKER.
JOHN LIDDERD. (L.S.)