IMPROVEMENTS IN TURRETS FOR MOUNTING HEAVY GUNS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Henry William Harman at the
Office of the Commissioners of Patents, with his Petition, on the
17th December 1872.
I, HENRY WILLIAM HARMAN, of Manchester, in the County of
Lancaster, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN TURRETS FOR MOUNTING HEAVY GUNS," to be
as follows:-
This Invention has for its object improvements in turrets for mounting
heavy guns.
I avoid entirely the use of rivets in the interior of the turret and
I form the drum of the turret of outer and inner armour plates bent to
the required curve.
A timber packing is placed between the inner and outer plates, and
they are bolted through with armour plate bolts. To give greater
strength at the embrasure an additional armour plate is employed; it is
inserted between the outer and inner plates, the thickness of the timber
packing being reduced to admit it.
The drum stands upon beams of iron or of timber stiffened by bolting
stout iron plates to them upon each side or with a single plate in the
centre. The beams radiate from a centre pivot supported upon a step,

page_text: "
and at their outer ends immediately under the drum they rest upon a
frame consisting of two concentric rings in which the axes of numerous
wheels are received. These wheels rest upon a ring rail laid upon a
firm foundation, and together with the centre pivot they carry the
weight of the turret. The drum is roofed over by means of radial iron
rafters, each of which at the outer end is stepped into a notch in the
side of the drum, and at the inner end is secured to a ring. The
structure is closed in by armour plates laid upon the rafters and held
down by vertical bolts passed through the timber packing from top to
bottom of the drum. The opening of the ring in the centre of the roof
serves for the ventilation of the turret, or it can be closed or partially
closed by a circular armour plate dropped into it.
Beneath the floor of the turret a ring of teeth is fixed and a pinion
gearing with these teeth and driven by a steam engine or hand power
rotates the turret. The turret is surrounded by a glacis ring of
armour plates.
⚫ Sometimes in place of supporting the turret around the periphery by
wheels carried by a frame of two concentric rings, I fix a circular rail
upon the under side of the framework beneath the drum, and I interpose
a ring of rollers between this rail and the similar ring rail upon the
foundation. The roller frame is constructed as a circular box girder;
the rollers project through openings in the top and bottom of the ring,
and pins or axes pass through the rollers and through the side of the
circular girder. On the outer or inner side of the girder a number of
small friction wheels are carried upon vertical axes, and these wheels run
upon the side of a vertical flange formed in connection with the fixed
supporting ring rail, and thus I avoid radial arms.
Sometimes in place of the central pivot I have a cylindrical trunk at
the centre of the turret to pass the shot and cartridges to the guns when
in action and also for entering the turret. When the centre pivot is
dispensed with I support the floor of the turret immediately around the
trunk by another ring of rollers similar to that already described.