Improvements in Hydraulic Winches for Hoisting and Lowering Boats or other Loads.
Year: 1899

page_text: Date of Application, 15th July, 1899
Complete Specification Left, 17th Apr., 1900-Accepted, 19th May, 1900
PROVISIONAL SPECIFICATION.
Improvements in Hydraulic Winches for Hoisting and Lowering
Boats or other Loads.
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:-
_
This invention relates to winches worked by hydraulic engines for hoisting
and lowering boats and other loads, provided with special safety brakes controlled
by hydraulic pressure.
The hydraulic engine employed is preferably of the three cylinder kind working
a shaft which is connected by suitable gear to a spur wheel on the axis of a
grooved barrel arranged to take a wire rope led over suitable guide pulleys to
the boat or other load. On the barrel shaft is a brake drum provided with a
brake strap which, when the engines are not working, is tightened on the drum
preventing the barrel from revolving. But when the engines are started in either
direction, and when there is sufficient pressure to work safely the pressure acting
in a hydraulic cylinder in opposition to the spring releases the brake strap.
The supply of fluid to this releasing cylinder is controlled by a valve attached
to the plunger of another hydraulic cylinder which is subject to a spring adjusted
to the desired working pressure so that the valve is not opened to supply the
brake releasing cylinder unless the pressure is sufficient to compress the spring.
The admission of fluid to the pressure controlling cylinder is determined by a
valve which is connected to the starting valves or gear of the hydraulic engine
in such a way that it is opened only when the engine is working in either direction.
Thus the release of the brake strap is subject to two conditions for ensuring
safety-first, the engine must be in condition to drive the winch, and, secondly,
the pressure of the fluid which works the engine must be sufficient to control
the load on the winch.
Instead of rigidly fixing the brake drum and spur wheel upon the barrel shaft,
they may be clutched to the shaft by friction plates pressed together by a
spring, the first, third and other odd plates being incapable of turning on the
shaft but free to turn within the hollow boss of the brake drum whilst the second.
fourth and other even plates are incapable of turning within the boss but free to
turn around the shaft. The spring which presses the plates together is held in
a sleeve fitted with packing on the end of the shaft and constituting a hydraulic
cylinder to which fluid under pressure can be admitted when desired, so as to
lessen or withdraw the spring pressure from the friction plates and thus release
the barrel shaft from the brake drum and spur wheel. The fluid admitted for
this purpose to the sleeve is controlled by a suitable valve.
In this way the load may be lowered without having to work the engine and

page_text: gear, the friction plates operating as a brake of more or less power according as
they are released to a less or greater extent by the hydraulic pressure acting in
the sleeve of this shaft.
11
1
Г
1000
ABEL & IMRAY,
Agents 'for the Applicants.
Improvements in Hydraulic Winches for Hoisting and Lowering
Boats or other Loads.
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:-
-
This invention relates to winches worked by hydraulic engines for hoisting
and lowering boats and other loads, provided with special safety brakes controlled
by hydraulic pressure, as we shall describe referring to the accompanying drawings.
Fig. 1 is a side view and Fig. 2 is an end view partly in section of a winch
according to this invention; Fig. 3 is a longitudinal section, Fig. 4 is a plan and
Fig. 5 is a transverse section of the valves for hydraulic control of the brake.
Fig. 6 is a longitudinal section of the brake clutch.
The hydraulic engine employed is preferably of the kind having three
cylinders a working a shaft 6 which has on it a pinion c gearing with an inter-
mediate wheel d on a shaft z on which is a pinion e gearing with a wheel fon
the shaft of the grooved barrel g or it might be connected by other suitable gear
to the spur wheel f. The barrel g is arranged to take a wire rope,led over suit-
able guide pulleys to the boat or other load. On the barrel shaft is a brake
drum h provided with a jointed brake strap k which, when the engines are not
working, is tightened on the drum h preventing the barrel g from revolving.
For this purpose, the two ends of the brake strap k are jointed to the short arm
of a lever the long arm of which is linked to a piston m urged by a spring n
towards the bottom of the cylinder p in which the piston works, so that when
there is no pressure in the cylinder, the spring acting through the lever tightens
the brake strap and so prevents the barrel y from revolving. But when the
engines are started in either direction, and when there is sufficient pressure to
work safely, the pressure acting in the cylinder p in opposition to the spring #
releases the brake strap.
The supply of fluid to the releasing cylinder p is controlled by a slide valve
attached to the plunger r of another hydraulic cylinder which is subject to a
springs, adjusted to the desired pressure for working the engine so that the
valve q is not opened to supply the brake releasing cylinder p unless the pressure
is sufficient to compress the spring s.
The admission of fluid to the pressure controlling cylinder t is determined by a
valve which is connected to the starting valves or gear of the hydraulic engine
in such a way that it is opened only when the engine is working in either
direction.
Thus the release of the brake strap k is subject to two conditions for ensuring
safety first, the engine must be in condition to drive the winch, and secondly, the

page_text: pressure of the fluid which works the engine must be sufficient to control the load
on the winch.
Instead of rigidly fixing the brake drum h and spur wheel f upon the barrel
shaft, they may be clutched to the shaft as shewn in Fig. 6 by friction plates v
pressed together by a spring 1, the first, third and other odd plates being in-
capable of turning on the shaft but free to turn within the hollow boss of the
brake drum whilst the second, fourth and other even plates are incapable of
turning within the boss but are free to turn around the shaft. The spring w
which presses the plates together is held in a sleeve fitted with packing on the
end of the shaft and constituting a hydraulic cylinder to which fluid under
pressure can be admitted when desired, so as to lessen or withdraw the spring
pressure from the friction plates and thus release the barrel shaft from the brake
drum and spur wheel. The fluid admitted by pipe y for this purpose to the
sleeve is controlled by a suitable valve worked by hand.
In this way the load may be lowered without having to work the engine and
gear, the friction plates operating as a brake of more or less power according as
they are released to a less or greater extent by the hydraulic pressure acting in
the sleever.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is:-
1. In combination with a winch worked by hydraulic engines, a brake drum
with strap normally tightened by a spring urged lever which is linked to a
piston in a hydraulic cylinder provided with valves so arranged that fluid under
pressure is admitted to the cylinder to act against the spring and so release the
brake only when the engines are in working condition, and the working fluid
has a determined pressure substantially as and for the purpose set forth.
2. In combination with a winch worked by hydraulic engines, a brake drum
and spur wheel free on the barrel shaft and provided with a friction clutch
normally tightened by a spring contained in a sleeve which is arranged to operate
as a hydraulic cylinder so that when fluid under pressure is admitted to it, it
moves back relieving the spring pressure on the clutch substantially as described.
Dated this 17th day of April 1900.
ABEL & IMRAY,
Agents for the Applicants.