AN IMPROVED CONSTRUCTION OF TURNTABLE
Year: 1867

page_text: LETTERS PATENT to Henry Bridgewater, of Watford, in the County of
Herts, Civil Engineer, for the Invention of "AN IMPROVED CONSTRUCTION OF
TURNTABLE."
Sealed the 16th July 1867, and dated the 22nd January 1867.
PROVISIONAL SPECIFICATION left by the said Henry Bridgewater at the
Office of the Commissioners of Patents, with his Petition, on the 22nd
January 1867.
I, HENRY BRIDGEWATER, of Watford, in the County of Herts, Civil Engineer,
do hereby declare the nature of the said Invention for "AN IMPROVED CON-
STRUCTION OF TURNTABLE," to be as follows:-
This Invention relates to a novel construction of turntable which will
possess an equal sustaining power or nearly so on the main and transverse
tracks with which it may be furnished in contradistinction to the ordinary
turntables which have their maximum strength in the direction of one line of
rails and comparative weakness in the direction of a crossing line of rails;
this advantage I attain mainly by making the rails which form the tracks for
the carriages to pass over integral parts of the turntable.
Suppose it is required to construct a turntable with two tracks crossing each
other at right angles, the rails which form the main track I form in one
continuous piece, merely indenting their heads to allow of the flanged wheels
as they are runy on to the transverse track passing over them, and I thus
secure the full strength or nearly so of these rails. The rails of the transverse

page_text: track I form in three pieces to leave spaces for the flanges of the wheels when
passing over the main track; but I ensure for these rails a sustaining power
by underlying girders, as will be now explained.
The rails I prefer to use are the well-known bridge rails, and these I secure
cach to a pair of channel-iron girders, rivetting the upper flange of a girder
to each flange of the bridge rail. The double girders thus formed will in the
case of the transverse rails run unbroken through their whole length, which
will be somewhat short of the length of the rails, but the girders for the main
rails (which will also stop short of the length of those rails) will be broken to
admit of the transverse girders crossing them. The whole may be secured
together by coupling plates, or angle iron and rivets if thought desirable. To
carry the boss which is to receive the central stud axle of the turntable I use
channel iron of a somewhat smaller section than that forming the girders, and
suitable lengths of this iron I bend to embrace the boss casting, and the ends
I rivet to the girders, thus connecting both ends directly and similarly with the
centre. On the stud axle a loose boss is mounted to receive and carry the
inner ends of a series of radial arms, which are each provided at their outer
ends with an antifriction roller. An annular race is formed of railway iron at
the bottom of the recess, in which the turntable is mounted, and at the edge
of the turntable an annular ring is formed of railway iron, rivetted to the ends
of the track rails, and thus serving to brace them together. The antifriction
rollers lie between these rings, and serve to sustain and distribute the weight
of the load. By reason of the thickness of the turntable at this part being
practically reduced to the depth of the upper ring, a larger diameter of anti-
friction roller with a given depth of table can be used than heretofore, which
is of no small advantage in easing the working of the table, and lessening the
depth required for the foundations.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed.
by the said Henry Bridgewater in the Great Seal Patent Office on the
22nd July 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BRIDGEWATER, of Watford, in the County of Herts, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of January, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirtieth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Bridgewater, Her special licence that I, the said Henry Bridgewater,
my executors, administrators, and assigns, or such others as I, the said Henry
Bridgewater, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED CON-
STRUCTION OF TURNTABLE," upon the condition (amongst others) that I, the sai
Henry Bridgewater, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Bridgewater, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed, and to the
letters and figures marked thereon (that is to say) :-
This Invention relates to a novel construction of turntable which will
possess an equal sustaining power or nearly so on the main and transverse
tracks with which it may be furnished in contradistinction to the ordinary
wrought-iron turntables which have their maximum strength in the direction
of one line of rails and show comparative weakness in the direction of a crossing
line of rails; this advantage I attain mainly by making the rails which form
the tracks for the carriages to pass over material parts of the framing of the
turntable.
In the accompanying Drawing I have shewn my Invention as applied to a
turntable with two tracks crossing each other at right angles, but it will be
obvious that turntables with more tracks may be constructed on the same
principle.
Fig. 1 is a plan view of the turntable with a portion of the platform and
rails removed the better to show its construction; and Fig. 2 is a sectional
elevation of the same; Fig. 3 is an enlarged sectional view of the arrange-
ment for locking the turntable to the casing in which it is mounted; Fig. 4
is a section shewing the manner of mounting the track rails on supporting
channel girders; and Fig. 5 is an enlarged view, shewing the mode of con-
necting the rails with the rim of the turntable.

page_text: A, A, Figures 1 and 2, are the rails which form the main track; these
I form in one continuous piece, merely indenting their heads, as shewn at a, a,
to allow of the flanged wheels of the carriages as they are run on to the
transverse track passing over them, and I thus secure the full strength or
nearly so of these rails. The rails of the transverse track are shewn at B, B;
these I form in three pieces to leave spaces for the flanges of the wheels when
passing over the main track, but I ensure for these rails a sustaining power
by underlying girders, as will be now explained.
The track rails I prefer to use are the well-known bridge rails, and these
I secure each to a pair of channel iron girders, as shewn at C, C, in the
section Fig. 4. The upper flange of a girder C is rivetted to each flange of
the bridge rail. The double girders thus formed will in the case of the
transverse track rails B run unbroken through their whole length, which will
be somewhat short of the length of the rails, but the girders for the main rails
(which will also stop short of the length of those rails) will be broken to admit
of the transverse girders crossing them. This arrangement is clearly shewn
in the detached sectional view, Fig. 4.
Where these breaks occur in the
girders I prefer to secure the parts together by means of coupling plates D,
and bolts, and nuts, or rivets. The channel girders are made shorter than the
rails, as shewn at Fig. 5, to allow of the latter being secured to the rim of the
table for the purpose hereafter explained. E is a cast-iron boss, which is to
receive the central stud axle F of the turntable; this boss I secure to the
framing of the turntable by means of channel iron of a somewhat smaller
section than that forming the girders C; suitable lengths G, G, of this iron
I bend to embrace the four hollow sides of the boss casting, and I make them
fast to the boss by screw bolts and nuts, as shewn at Fig. 1; their ends
I insert in the channels of the girders C, and I secure them to the girders by
rivets or screw bolts and nuts. On the stud axle F a loose boss II is mounted
to receive and carry the inner ends of a series of radial arms I, which are
each provided at their outer ends with an antifriction roller 1*. An annular
race X is formed of railway iron at the bottom of the turntable case or the
recess in which the turntable is mounted. The turntable is fitted at its edge
with an annular rim formed of inverted bridge rail iron L; to this rim or
ring L the ends of the track rails are rivetted, and it thus serves to brace the
track rails together. The antifriction rollers lie between these rings K and L,
and serve to sustain and distribute so much of the weight of the load as is not
taken by the stud axle F. The top of this axle is hollowed to form a socket
for an antifriction ball, and a cap plate F* similarly recessed is bolted to the
cast-iron boss E, and bears upon the antifriction ball, whereby the central

page_text: weight of the table is transferred to the stud axle. By reason of the thickness
of the turntable at the part which bears upon the antifriction rollers being
practically reduced to the depth of the upper ring, as shewn at Fig. 5, a larger
diameter of antifriction roller with a given depth of table can be used than
heretofore, which is of no small advantage in easing the working of the table
and lessening the depth required for the foundations. The turntable casing
I form of segments of wrought-iron M bolted together and fitted at bottom
with angle iron N, as shewn in the section Fig. 3, and 1 bed the casing upon
timbers, as shewn in the plan view, Fig. 1. The lip or rim of the case consists
of a ring of wrought iron O rivetted to the segments, as also shewn in Fig. 3.
The locking of the turntable in its proper positions is effected by allowing
tumblers P, pivotted to arms Q, to drop into notches cut in the rim O. For
supporting the platform of the turntable short timbers R having their ends
inserted in the channels of the girders C are used, and upon them braced
planks are laid.
It will be seen by reference to Fig. 2 that the rim of the turntable instead
of lying within the case, as usual in this arrangement, overlies its upper edge.
By this means dirt and other extraneous matters are prevented from working
in under the table.
Having now set forth the nature of my Invention, and explained the manner
of carrying the same into effect, I wish it to be understood that I claim,-
First, the construction of turntable above described, wherein the track rails
are used as material portions of the framework of the table.
Secondly, the means above described whereby the thickness of the table at
the part where it bears upon the antifriction rollers is reduced for the purpose
above set forth.
In witness whereof, I, the said Henry Bridgewater, have hereunto set
my hand and seal, the Nineteenth day of July, in the year of our
Lord One thousand eight hundred and sixty-seven.
H. BRIDGEWATER.
L.S.)