provements in the Rotating, and Braking Mechanism, of Heavy Turntables or Turrets".
Year: 1898

page_text: Date of Application, 18th Oct., 1898
Complete Specification Left, 10th July, 1899-Accepted, 12th Aug., 1899
66
PROVISIONAL SPECIFICATION,
Improvements in the Rotating, and Braking Mechanism, of Heavy
Turntables or Turrets".
We, ARTHUR TREVOR DAWSON, of Vickers Sons & Maxim Limited, of 28 Victoria
Street, Westminster, in the County of London, Superintendent of Ordnance
Works, and JAMES HORNE, 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:-
Our invention relates to the rotating and braking mechanism of heavy turntables
or turrets, on board of warships.
According to our invention, we employ a single brake, which is always in action;
whether the rotating mechanism is worked by hand or by power, being always in
positive connection with the operating shaft, and so arranged that no disconnecting
gear is required when a change is made from power to hand working.
The power for rotating these heavy turrets or turntables is usually transmitted
through a vertical shaft having on its lower end a spur wheel for power working, a
worm wheel for hand working, and a brake drum provided with a flexible brake
strap tightened by a spring. The spur wheel gears with a pinion on the shaft of a
hydraulic engine and the worm wheel gears with a worm driven by a set of crank
handles worked by hand.
The worm wheel drives the shaft through a set of friction plates pressed together
by a spring, the odd plates being connected to the shaft and the even plates con-
nected to the worin wheel.
The teeth of the worm are at such an angle that the wheel cannot drive it. We
utilise this mechanism as a brake for power working as well as for hand working,
dispensing with the separate brake drum and strap.
For this purpose, we form the lower end of the vertical shaft as the plunger of a
hydraulic cylinder by which the pressure of the spring acting on the friction plates
is relieved so that the turret can be freely rotated by the hydraulic engine.
When the brake drum and strap are employed we connect the worm wheel by the
friction plates not directly to the vertical shaft but to a sleeve on it the plates being
pressed together by a spring and compressing nut self contained on the sleeve.
The shaft is then connected by a clutch either to the spur wheel driven by the
engine or to the sleeve driven by the worin wheel. Usually the valves governing
the hydraulic pressure for working the brakes are so arranged that the brake can
be taken off only when the working pressure available is above 100 to 500 lbs. per

page_text: square inch. This results from the working of the valve for releasing the brake by
a spring loaded ram, always subject to the pressure when it is turned on to the
engines whether they are in motion or not. According to our invention we provide
a secondary slide or valve working transversely to the spring loaded ram and acting
in such a manner that it can only admit water to move the spring loaded rain when
the engines are in motion or about to be put in motion in either direction, and
when the pressure is above 400 to 500 lbs. per square incb.
For this purpose we connect the stem of this transverse valve to the piston of the
reversing cylinder on to the piston of one of them when three are employed, as
they sometimes are, for starting, stopping, reversing and controlling the notion of
the hydraulic engines. When these engines are at rest, the piston in the reversing
cylinder or in each of them occupies a central position, but when the engines are in
motion the piston occupies some position to the one side or the other of the central
position.
The valve above mentioned being connected to this piston moves with it and in
doing so adimits pressure water to the cylinder of the spring loaded rain; but when
it is in the central position, this cylinder is connected to exhaust only, so that the
spring forces the ram inwards, moving the valve which controls the admission of
water to the cylinder for releasing the brake so that this cylinder is likewise con-
nected to exhaust. This arrangement ensures that the brake is always on while the
piston of the reversing cylinder is centered and the engines are at rest, and that the
brake is always off when the engines are in inotion.
Dated this 19th day of October 1898
ABEL & IMRAY,
Agents for the Applicants.
"Improvements in the Rotating, and Braking Mechanism, of Heavy
Turntables or Turrets,"
We, ARTHUR TREVOR DAWSON, of Vickers Sons & Maxim Limited, of 28 Victoria
Street, Westminster, in the County of London, Superintendent of Ordnance Works,
and JAMES HORNE, 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 performed, to be particularly described and
ascertained in and by the following statement:—
Our invention relates to the rotating and braking mechanism of heavy turntables
or turrets on board of warships. This mechanism usually comprises an upright
shaft on which there is a pinion gearing with a circular rack so arranged that when
the shaft is rotated the turret, or turntable is caused to revolve.
The rotation of the shaft is effected in either of two ways, either by a hydraulic
engine on the shaft of which there is a pinion gearing with a wheel on the upright
shaft, or by winch gear worked by hand so as to turn a worm wheel on the upright
shaft. In either case means have to be adopted to prevent the turret froin turning
when it is required to remain at rest, and for this purpose a brake is usually applied
to the upright shaft, and this in such a manner as to be always released when the
turret is to be turned either by the engines or by hand but to remain applied to the
shaft when no power is employed to turn it or when the hydraulic pressure is
insufficient.
We shall describe mechanism according to our invention for effecting the rotation
and braking of the upright shaft under the conditions above stated, referring to the
accompanying.drawings.

page_text: Fig. 1 is a vertical section of the rotating and braking mechanism arranged so
that the worm wheel clutch operates as the brake.
Fig. 2 is a vertical section of the mechanism when the braking is effected by a
friction strap acting on a brake wheel on the shaft.
Figs. 3 and 4 are sections on planes at right angles to each other and Fig. 5 is a
plan of the valves for releasing the brake when the shaft has to be turned.
Referring first to Fig. 1, is the upright shaft on which is fitted free to revolve
a toothed wheel which can be clutched to the shaft a by means of a clutch c
worked by a lever d, screw and hand wheel e. There is also fitted free on the shaft a
a worm wheelf having a hollow boss in which are a number of friction plates y. All
the odd plates are notched or shaped internally to slide along keys or flats on the
shaft a and all the even plates are notched or shaped externally to slide along keys
or flats within the boss of the wheel f. These plates are pressed into close contact
by a spring. A worm gears with the worin wheel of the pitch being such that
the wheel cannot drive the worm, The lower end of the shaft a has fitted on it
with cup leathers a sleeve containing the spring the lower end of which bears on
a collar m screwed on the shaft and secured by a lock nut n.
Below the nut n the shaft a has a reduced part p which extends into a cavity in
the lower part of a casing q, this cavity communicating by a pipe with a valve
connected as will hereafter be described to the reversing valve of the hydraulic
-engine which by suitable gear works the toothed wheel b. The worm & is on a shaft
worked by any suitable hand gear.
The lower part of the shaft a is bored upwards to a point above cup leathers s
where there is a cross bore, so that. liquid under pressure supplied by the pipe 1 can.
act as in a hydraulic press, pushing down the sleeve and the springs and so
-relieving the frictional pressure of the plates g.
The operation of the apparatus is as follows:-
When the shaft a is worked by the hydraulic engine driving the wheel b, then
that wheel is clutched to the shaft a and the hydraulic pressure which works
the engine being communicated from the reversing valve of the engine through the
piper causes release of the friction plates g so that they do not tend to drive the
worm wheelf. When the shaft a is worked by hand gear driving the work, then
the wheel bis unclutched, and there being no pressure communicated through the
pipe the friction plates are pressed into close contact by the spring / so that they
clutch the worn wheelf to the shaft a.
As the wheel is held stationary by the worm k, when that worm is stationary,
the friction plates y operate as a brake preventing the shaft a from revolving and
consequently holding stationary the turret or turntable which is geared to the
shaft a.
As this gearing, as well as the hydraulic engine and its gearing to the wheel b,
and the hand gear for working the worm is all of ordinary known construction
and arrangement, we have not shewn them in the drawing and we make no claim
in respect of them.
Referring now to Fig. 2 the upright shaft a has loose on it the wheel b which can
be clutched to the shaft by the upper cogs of a clutch c worked by a lever d and
screw and hand wheel e. The worin wheel is fixed on a sleeve t which is tree to
revolve on the shaft a but can be clutched to it by the lower cogs of the clutch c
when the upper cogs are disengaged from the wheel b. On the shaft is fixed the
brake wheel provided in the usual way with a strap which is tightened on the
wheel by a spring but is released by the plunger of a hydraulic cylinder supplied
with fluid under pressure when the fluid is acting in the hydraulic engines which
work the wheel b.
The flow of the fluid under pressure to the cylinder for releasing the brake is
regulated by the valve shewn in Figs. 3, 4 and 5. Of these the slide valve v governs
a passage 1 to the brake releasing cylinder and an exhaust passage 2. This valve
is attached to the plunger of a hydraulic cylinder w subject to a strong spring y in
the usual way, but the ports 3 and 4 of this cylinder. and its exhaust port 5 are

page_text: governed by a transversely arranged slide valve according to our-invention, the rod
of this valve being linked to the ordinary reversing valves of the hydraulic engine
or one of them. When this reversing valve is in middle position the hydraulic
engines are stopped and then the valve is in middle position, both of the
ports 3 and 4 then communicating with the exhaust port 5 so that there is no
pressure in the cylinder and the plunger is then forced in by the spring y moving
the valve to the position shewn in which position the port 1 communicates with
the exhaust port 2 relieving the pressure in the brake releasing cylinder, so that the
brake is not released. If however the reversing valve of the hydraulic engine
be moved so as to cause the engine to move in either direction, then the valve x is
moved with it so as to close the exhaust port 5 and to put the one or the other of
the ports 3, 4, in communication with the supply pipe of pressure fluid. The
fluid thus admitted to the cylinder w acts on its plunger and if the pressure is
sufficient to compress the spring y the plunger is moved to the right, moving with
it the valve v and so putting the passage 1 in communication with the supply pipe z
so that pressure fluid passes to the brake cylinder and acts there to release the
brake. If the fluid pressure happens to be insufficient to compress the spring y
then the valve is not moved to the right and the brake is not released.
When the apparatus shewn in Fig. 1 is employed, the pipe is in direct connection
with the passage 1 governed by the valve vas above described, so that the pressure
on the sleeve Fig. 1, is determined in the same way as the pressure for releasing
the brake, as described with reference to Figs. 3, 4 and 5.
Although we have described the transverse valve x as being connected to reversing
valve of the hydraulic engine, it may obviously be worked, from another reversing
appliance, such as the piston of a reversing cylinder.
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 combination with the upright shaft employed for rotating a turntable or
turret, a wheel adapted to be worked by a hydraulic engine and means of clutching
it to the shaft, a worm wheel gearing with a worm adapted to be worked by hand
gear, a set of friction plates and spring arranged to clutch the worm wheel to the
shaft, and a cavity around the shaft connected by a pipe to the supply of fluid
pressure for the hydraulic engine, so as to release the friction clutch of the worm
wheel when the engine works, substantially as described with reference to Fig. 1.
2. The combination of the upright shaft, the worm and wheel and the friction
plates and spring arranged to operate as a brake when the bydraulic engine is
not at work, substantially as described.
3. In combination with the upright shaft employed for rotating a turntable or
turret, a brake wheel fixed on the shaft, a wheel adapted to be worked by a hydraulic
engine and means of clutching it to the shaft, a worm wheel adapted to be worked
by hand gear and fixed on a sleeve adapted to be clutched to the shaft when the
wheel worked by the engine is unclutched and a set of friction plates and spring
arranged to clutch the worm wheel to the sleeve, substantially as described with
reference to Fig. 2.
4.- In-eombination-with-the-spring-plunger-cylinder-and-the
releasing-cylinder-a-transversely-arranged-valve
valve--for-the-brake
linked-to-a-reversing-appliance-of-the
hydraulie-engine-and-governing-the-ports-of-the-spring-plunger-cylinder-substantially
as-and-for-the-purpose-set-forth.
T
1000