Improvements in Ammunition Hoists Employed on Ship Board.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Ammunition Hoists Employed on Ship Board.
We, ARTHUR TREVOR DAWSON, Late Lieutenant R.N., Director and Super-
intendent of Ordnance Works, THOMAS THACKERAY, Mechanical Engineer, both
of Vickers, Sons, & Maxim Limited, of 28, Victoria Street, Westminster, in
the County of London, and JAMES HORNE, also of Vickers, Sons, & Maxim.
Limited, of Barrow-in-Furness, in the County of Lancaster, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the hoists employed on ship board to raise ammuni-
tion to position for charging breech loading guns mounted in turrets, barbettes
or the like.
The chief objects which we have in view are to arrange the hoist and its
hydraulic crane work in such a way that the cage is locked at the bottom of
the lift until it is released by the operator there, that the cage in the upper
part of its course travels along a suitable curve at the breech of the gun until
it reaches a stop fixed on the gun carriage, and that the lift rope accommodates
itself without change of length to the various positions which the gun may take
in its elevation or depression.
For this purpose we mount at the bottom of the hoist frame a lever and catch
which are urged in one direction by a spring but are held back by a stop pawl.
When the cage reaches the bottom of its course it moves this pawl so as to release
the catch and lever whereupon the spring operates causing the catch to engage
with a corresponding catch on the cage and to hold it down. The lever is con-
nected to a relief valve which is held open by it, allowing the pressure water to
escape while the cage remains down to be charged, so that the hydraulic crane of
the hoist cannot be worked until the operator below releases the cage and so
closes the relief valve.
The catch is held disengaged by a pawl carried on the cage. When the cage
ascends it carries this pawl with it and allows the stop pawl to resume its
normal position.
Instead of connecting the lever to a relief valve, it may be connected to the main
valve by opening which the crane is put in action, locking that valve and so
preventing the action of the crane until the cage is released by the operator
below.
The hydraulic crane employed is of the known kind having a vertical cylinder
and a plunger carrying several pulleys around which, the other corresponding
pulleys, and guide pulleys, a rope passes to the cage.
But besides the main cylinder of the crane we provide two small cylinders
one on each side of the main cylinder, the plungers of which are always subject
to the working pressure so as to keep a certain moderate strain on the rope when
the main plunger is relieved from pressure.
The cage is raised until it comes against a stop fixed on the slide girder of
the gun carriage being then in such a position that the projectile carried by it
is in line with the bore of the gun. The crane rope has its one end carried

page_text: over an overhead guide pulley and attached to the cage; its other end after
passing a guide pulley below is attached to the slide girder, so that when the
gun is elevated or depressed the length of rope remains unchanged, the one end
taking up what the other gives out.
The crane cylinder instead of being vertical and stationary may be horizontal
and fixed on the slide girder of the gun carriage so as to move up or down with
it as the gun is elevated or depressed. In this case the rope passes from the
crane over a guide pulley mounted on the slide girder under a pulley mounted
in the fixed framing below, over a guide pulley mounted on the top of the hoist
frame and down to an attachment on the cage. When this arrangement is em-
ployed, the rope, as in the former case, accommodates itself to the movements of
the slide girder in elevating or depressing the gun without any alteration of
its length, and without affecting the position of the cage relatively to the bore
of the gun.
The cage may be arranged in its ascent to swing a loading tray into the breech
of the gun, the loading tray being connected to a water supply the valve of
which is automatically opened when the tray is advanced into the bore, so that
water is discharged from perforations of the tray which is at the same time
rotated to thoroughly wash out the charge chamber.
Dated this 25th day of November 1898
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Ammunition Hoists Employed on Ship Board.
We, ARTHUR TREVOR DAWSON, Late Lieutenant R.N., Director and Super-
intendent of Ordnance Works, THOMAS TACKERAY, Mechanical Engineer, both
of Vickers, Sons, & Maxim, Limited, of 28, Victoria Street, Westminster, in
the County of London, and JAMES HORNE, also of Vickers, Sons, & Maxim
Limited, of Barrow-in-Furness, in the County of Lancaster, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
-
This invention relates to the hoists employed on ship board to raise ammuni-
tion to position for charging breech loading guns mounted in turrets, barbettes
or the like.
The chief objects which we have in view are to arrange the hoist and its
hydraulic crane work in such a way that the cage is locked at the bottom of
the lift until it is released by the operator there, that the cage in the upper
part of its course travels along a suitable curve at the breech of the gun until
it reaches a stop fixed on the gun carriage, and that the lift rope accommodates
itself without change of length to the various positions which the gun may take
in its elevation or depression.
For this purpose we arrange the apparatus as we shall describe referring to the
accompanying drawings. Fig. 1 is a side elevation of the ammunition hoist.
Figs. 2 and 3 are side and end views to an enlarged scale of the catch apparatus
at the bottom.
At the bottom of the hoist frame a we arrange a lever b and a catch c which
are urged in one direction by a spring p but are held back by a spring pawl p
engaging against a shoulder on a cam g which is fixed on the shaft of the lever
and catch c.

page_text: When the cage z reaches the bottom of its course a projection from its bottom
depresses the pawl so as to release the cam whereupon the spring d operates
causing the lever b to move to the left and the catch c to engage with a corre-
sponding catch f on the cage and to hold the cage down. The lever bis con-
nected by a rod g to a relief valve h which is held open allowing the pressure
water to escape if it should be admitted to the cylinder of the crane while the
cage remains down to be charged, so that the hydraulic crane k of the hoist cannot
be worked until the operator below releases the cage and so closes the relief
valve. When the operator having charged the cage with ammunition desires the
cage to ascend, he pulls the lever over to the right thus withdrawing the catch c
from fand thereupon a spring catch e which is pivotted on the cage engages
against a shoulder of the cam holding it until the cage so far ascends as to allow
the pawl p to engage again with the cam q.
The hydraulic crane k is of the known kind having a vertical cylinder and a
plunger carrying several pulleys around which and the other corresponding pulleys
and guide pulleys a rope passes to the cage.
But besides the main cylinder of the crane we provide two small cylinders m
one on each side of the main cylinder the plungers of which are always subject
to the working pressure, so as to keep the rope tight when the gun is depressed
while the cage is down. Obviously a single small cylinder might be employed
for this purpose.
The cage is raised travelling in the upper part of its course along curved guides
concentric with the trunnions until it comes against a stop n fixed on the slide
girder of the gun carriage being then in such a position that the projectile carried
by it is in line with the bore of the gun.
The crane rope has its one end carried over an overhead guide pulley *
and is attached to the cage at y its other end after passing a guide pulley & below
is attached to the slide girder at s so that when the gun is elevated or depressed,
the length of rope remains unchanged, the one end taking up what the other
gives out.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what
we claim is:-
1. In an ammunition hoist for use on shipboard the spring lever and catch
apparatus for holding the cage at the bottom of the hoist frame and its connection
to the relief valve of the hydraulic crane substantially as and for the purpose
set forth.
2. In combination with the main cylinder of the crane, a cylinder or pair of
small cylinders subject to constant pressure as and for the purpose set forth.
3. The attachment of the crane rope so that its length remains constant not-
withstanding change of elevation of the gun.
Dated this 16th day of September 1899.
ABEL & IMRAY,
Agents for the Applicants.