IMPROVEMENTS IN RAILWAY CHAIRS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said Henry Bridgewater at the
Office of the Commissioners of Patents on the 21st March 1882.
HENRY BRIDGEWATER of Watford in the County of Herts, Civil Engineer
"IMPROVEMENTS IN RAILWAY CHAIRS,"
This Invention relates to an improvement upon a Patent granted to me and
bearing date September 3rd 1869, No 2599 in which provision is made for securing
wooden wedges in railway chairs and maintaining the bite of the wedges upon the
inserted rails.
According to that Invention the face of the jaw of the chair against which the
wedge was to be brought in contact was cast with horizontal ribs or projections
which prevented a vertical movement of the wedge but offered no direct obstruction
to its working endwise under the vibration of the rail.
To remedy this defect I now propose to cast that face of the jaw against which
the wedge is to be driven with horizontal or vertical recesses which will allow of
the wedge when driven home expanding from its compressed state, and thus forming
obstructions to the endway motion of the wedge.
In preparing the pattern for the chair which is to have horizontal recesses in the
jaw I gouge out two, three, or more hollows having between them horizontal ribs.
These recesses may extend some two thirds of the length of the jaw, and where
they terminate the original thickness of the pattern will be maintained.
This thickness however I chamfer off towards both ends of the jaw, till the
thickness is diminished to an extent equal to the greatest depth of the recesses,
and I thus provide for the facile insertion of the wedge, as well as spaces which
will allow the wedge to swell and lock itself in position.
When forming the jaw with vertical recesses the parts of the face of the jaw
that possess the maximum thickness, and have the appearance of vertical projections,
I so form as to enable them to offer an obstruction to any tendency that the wedge
may have to rise in the chair.
Thus I indent these projections transversely in such a way that the indents will
take somewhat the appearance of ratchet teeth and while offering an effectual
bar to the rising movement of the wedge will present no obstacle to its being
driven into the chair.

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SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Bridgewater in the Great Seal Patent Office on the
20th September 1882.
HENRY BRIDGEWATER of Watford in the County of Herts Civil Engineer
"IMPROVEMENTS IN RAILWAY CHAIRS
"
This Invention relates to an improvement upon a Patent granted to me and
bearing date September 3rd 1869 No 2599 in which provision is made for securing
wooden wedges in railway chairs and maintaining the pressure of the wedges upon
the inserted rails.
According to that Invention the face of the jaw of the chair against which the
wedge was to be brought in contact was cast with horizontal ribs or projections
which prevented a vertical movement of the wedge but offered little or no direct
obstruction to its working end wise under the vibration of the rail.
To remedy this defect I now propose to cast that face of the jaw against which
the key or wedge is to be driven with bevilled ends to compress the key as it is
driven in, and with horizontal or vertical recesses in its face which recesses will
allow of the key or wedge when driven home expanding from its compressed state
and filling the recesses, thus forming obstructions to the endway and vertical
motion of the key or wedge.
In preparing the pattern for the mould in which to cast a chair having
horizontal recesses in the gripping jaw I gouge out two, three, or more hollows
having between them horizontal surfaces having the appearance of ribs but not
projecting beyond the plane vertical face of the jaw These recesses may extend
some two-thirds of the length of the jaw and where they terminate the original
thickness of the pattern will be maintained.
This thickness however I chamfer or bevil off towards both ends of the jaw till
the thickness is diminished to an extent equal to the greatest depth of the recesses,
and I thus provide for the facile insertion of the key or wedge and its forcible
compression when driven in, as well as spaces which will subsequently allow the
key or wedge to swell and lock itself in position.
When forming the gripping jaw with vertical recesses the parts of the face of
the jaw that possess the maximum thickness and have the appearance of vertical
ribs or projections, I so form as to enable them to offer an obstruction to any
tendency that the key or wedge may have to rise in the chair.
Thus I transversely indent the plane surfaces between the vertical recesses in
such a way that the indents will take somewhat the appearance of ratchet teeth,
and while offering an effectual bar to the rising movement of the key or wedge,
will present no obstacle to its being driven into the chair.
By constructing railway chairs with bevilled ends and a grooved gripping jaw
in the manner above described I am enabled to use keys with parallel sides which
may be driven in either right or left handed..
In the accompanying drawings Fig 1 is a partial longitudinal section of the
chair showing the rail firmly keyed in place-Fig 2 is a transverse section of the
chair taken in the line 1. 2 of Fig: 1, and showing the longitudinally grooved face
of the jaw, the key and rail being removed. Figures 3 and 4 are sectional plan
views of the jaw taken on the lines 1. 2 and 3. 4 respectively of Fig 2, and
showing the key or wedge expanded to fill the grooved or recessed jaw. Fig 5 is
a cross section of the key or wedge before insertion. Fig 6 is a partial longitudinal
section showing the indented or toothed surfaces between the vertical grooves in
the face of the jaw. Fig 7 is a transverse section of the chair taken on the line
1. 2 of Fig 6, and shewing the face of the jaw, the key and the rail being

page_text: removed; Figures 8 and 9 are sectional plan views of the jaw taken respectively
on the lines 1. 2 and 3. 4 of Fig 7. Fig 10 is a transverse section of the key or
wedge before insertion.
In these Figures A is the chair A' the jaw with a grooved or recessed face and
bevilled ends, B is the key or wedge and C is the rail. Referring to Fig 2 it will
be seen that the vertical face of the jaw A¹ is grooved longitudinally as at a a a a
leaving however portions a¹ of the plane vertical surface intact between the said
grooves a, which portions a³ have the appearance of ribs but which do not project
beyond the plane vertical surface of the jaw.
From the sectional views Figs 1, 3, and 4 it will be seen that this longitudinally
grooved jaw allows the face of the wooden key B to expand and fill the grooves a,
thereby preventing all endway motion of the key after it is knocked in, while the
parts a¹ serve to prevent the vertical movement of the expanding key.
The ends of the jaw A¹ are bevilled off at a² a², as shewn best in Figures 3 and 4,
and serve to forcibly compress the key or wedge B as it is driven home between the
rail C and the face of the gripping jaw A¹. The extent to which these ends are
bevilled off is about equal to the depth of the grooves or recesses formed in the face
of the jaw.
.
Fig 5 shows in cross section the key or wedge B before insertion, and the keys
may be driven with equal facility either from the right or left hand
It will be seen that the width of a key before insertion is equal to the greatest
horizontal breadth between the rail B and the bottom of the grooves a, but that
the key is compressed on insertion by being driven past the bevilled ends, and is
then free to expand and fill the grooves a.
The same principle of construction is carried out in a chair cast with vertical
recesses in the face of the gripping jaw as shown in Figures 6 and 7, but as in
this case there is rather greater tendency for the key to rise, indent the vertical
plane surfaces between the grooves or recesses with transverse indentations
giving to the said vertical surfaces as seen in vertical cross section a notched or
indented appearance (see Fig 6). These notched or indented surfaces a¹ between
the vertical grooves a, while effectually preventing the key from rising will offer
no obstruction to the insertion of the key. The jaw in this case is similarly
bevilled on at its ends, and the key is as before explained forcibly compressed
when driven over the bevilled surfaces, expanding into the recesses and also filling
the notches or indentations between the vertical recesses. The key is thus securely
held in place and maintains a firm pressure upon the inserted rail C.
Having now set forth the nature of my Invention of "Improvements in the
construction of Railway Chairs," I wish it to be understood that I claim:
First As an improvement in railway chairs, forming the jaw against which the
key or wedge is to be brought in contact, with bevelled ends to ensure the
compression of the key as it is driven in, and with recesses or hollows in its face
to allow the compressed key to expand and lock itself firmly in place, substantially
as described with reference to the drawings.
Secondly When employing vertical grooves or recesses for the key to expand and
lock into, the use of notched or indented surfaces substantially as and for the
purpose described with reference to Figures 6 to 10 of the Drawings.
In witness whereof I the said Henry Bridgewater have hereunto set my
hand and seal the twentyeighth day of August in the year of our
Lord One thousand eight hundred and eighty two :-