IMPROVEMENTS IN HYDRAULIC HOISTS
Year: 1872

page_text: LETTERS PATENT to Thomas Wrightson, of the Teesdale Iron Works,
South Stockton-on-Tees, in the County of York, Engineer, for the
Invention of "IMPROVEMENTS IN HYDRAULIC HOISTS."
PROVISIONAL SPECIFICATION left by the said Thomas Wrightson at
the Office of the Commissioners of Patents, with his Petition, on the
5th August 1872.
I, THOMAS WRIGHTSON, of the Teesdale Iron Works, South Stockton-
on-Tees, in the County of York, Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN HYDRAULIC HOISTS," to be as
follows:-
This Invention has for its object improvements in hydraulic hoists.
For this purpose a shaft is mounted on a framing above the platform to
which material has to be lifted. On this shaft are one or more fixed
pulleys and also a pulley running loose upon it but having a clutch face
so placed that a clutch moving on sliding keys on the shaft will make it
move round with the shaft when required. From the fixed pulley or

page_text: pulleys chains or ropes pass to two cages so that when one rises the other
falls. One cage is made so much heavier than the other that it will
always pull the latter up. This movement is controlled by a brake on
the fixed wheels.
Passing from the loose pulley is a chain or rope which descends to a
ram working in a vertical cylinder, the chain being by preference passed
round a sheave on the top of the ram to diminish the travel of the same.
The weight of this ram is made to exceed the load and weight of the
heavy cage, so that when the ram is at the top the clutch thrown into
gear and the exhaust valve of the cylinder opened the descending weight
of the ram pulls up the heavier cage, the lighter one of course descending,
the heavier cage is then held by the brake, and the clutch falling out of
gear the ram is pumped up again by a small donkey pump preparatory
to the next rise of the heavy cage, the chain passing from the ram being
kept taut and taken up on to the loose pulley by means of a counter-
balance weight carried by a chain from this pulley.
The heavy cage may be allowed to descend whenever required without
affecting the rising of the ram, the shaft merely revolving inside the
loose pulley.
The throwing in of the clutch and the opening of the exhaust valve
for the descent of the ram and pulling up of the heavy cage being
simultaneous actions can be effected by the movement of one lever
handle.
In a similar manner a hoist in which a single cage only is used may
be arranged so that the cage is raised by the weight of the ram and is
held at the top, and also lowered by the brake, whilst the ram can be
raised without interfering with the lowering of the cage.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Wrightson in the Great Seal Patent
Office on the 5th February 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, TпомАS
WRIGHTSON, of the Tecsdale Iron Works, South Stockton-on-Tees, in
the County of York, Engineer, send greeting.
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of August, in the year of our
Lord One thousand eight hundred and seventy-two, in the thirty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Wrightson, Her special license that
I, the said Thomas Wrightson, my executors, administrators, and assigns,
or such others as I, the said Thomas Wrightson, my executors, admini-
strators, 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 "IMPROVEMENTS IN HYDRAULIC HOISTS,"
upon the condition (amongst others) that I, the said Thomas Wrightson,
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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Wrightson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
This Invention has for its object improvements in hydraulic hoists.
For this purpose a shaft is mounted upon a framing above the platform
to which material has to be lifted. On this shaft are one or more fixed
pullics and also a pulley running loose upon it but having a clutch
face so placed that a clutch moving on sliding keys on the shaft will
make it move round with the shaft when required. From the fixed
pulley or pullies chains or ropes pass to two cages so that when one
rises the other falls. One cage is made so much heavier than the other
that it will always pull the latter up. This movement is controlled by
a break on the fixed wheels.
Passing from the loose pulley is a chain or rope which descends to a
ram working in a vertical cylinder, the chain being by preference passed
round a sheave on the top of the ram to diminish travel of the
same. The weight of this ram is made to exceed the load and weight of

page_text: the heavy cage, so that when the ram is at the top the clutch thrown
into gear and the exhaust valve of the cylinder opened the descending
weight of the ram pulls up the heavier cage, the lighter one of course
descending, the heavier cage is then held by the brake, and the clutch
falling out of gear the ram is pumped up again by a small donkey pump
preparatory to the next rise of the heavy cage, the chain passing from
the ram being kept taut and taken up onto the loose pulley by means of a
counterbalance weight carried by a chain from this pulley.
Figure 1 is a side clevation, Figure 2 an cnd elevation, and Figure 3 a
plan of an hydraulic hoist constructed according to my Invention.
a, a, are upright columns, and at the top of these columns is a plat-
form b, at the level to which the materials or loads are to be raised;
c and c³ are two cages which are able to travel up and down between
guides fixed upon the columns a from the ground level to the level of
the platform b. The cages or carriers c and c¹ are connected together
by two chains passing over the chain wheels d, d. These wheels are
fixed upon a shaft e which is carried in bearings upon a framing f
erected over the platform b. The cage c is sufficiently heavy to cause it
to descend to its lower position whenever it is set free, and in doing so
it will raise the cage c¹ with any load there may be upon it. There are

page_text: flanges upon the chain wheels d, d, receiving brake straps 5, by
means of which the cages can be held from moving and their motion
can be controlled. hand are an hydraulic cylinder and ram, and by
a steam engine or other power water or other liquid can be pumped into
the cylinder to raise the ram.
means of which the cages can be held from moving and their motion
can be controlled. h and ' are an hydraulic cylinder and ram, and by
a steam engine or other power water or other liquid can be pumped into
the cylinder to raise the ram.
By self-acting gear, not shewn in the Drawings, the supply of water
or liquid is stopped when the ram is fully raised.
The head of the ram moves between suitable guides, and it carries a
pulley i. A chain & fixed at one end above the head of the ram passes
beneath the pulley i and then over the guide pulley to a wheel m, to
the periphery of which it is fixed or upon which it is wound. The
wheel m is able to turn freely upon the shaft e.
n is another chain,
which is fixed to and wound around the wheel m, from which it passes
over the guide pulley o to a weight hanging within one of the columns a ;
5 the object of this weight is simply to keep the chain k taut. p is a
clutch upon the shaft e, by means of which the wheel m can at will be
made fast with the shaft; q is a lever handle for working the clutch p,
it is also connected by a rod r to a valve which lets the water or liquid
escape from the ram cylinder h, and when the clutch has hold of the
wheel m this valve is open, and vice versa.
The weight of the ram h¹ is sufficient to lift the heavy cage c with its
load upon it, so that supposing the ram to have been raised on
throwing in the clutch p it commences to descend and so brings up the
cage c at a speed regulated by the brakes, or by regulating the escape of
water from beneath the ram by the exhaust valve. As soon as this cage
is at the top and has been secured by the brakes the clutch p is thrown
out and the engine commences to pump the ram ³ up again ready to be
again used.
When the cage c¹ is to be lifted the brakes are slacked and the cage c
descends and draws the cage c¹ up to the platform.
As already mentioned a hoist with a single cage may be constructed
and worked in the manner above described. Or the hoist may have two
cages and there may be two hydraulic rams, one to lift each cage. Such
an arrangement is shewn on Sheet 2 of the Drawings. Figure 41 is a
¡ side clevation and Figure 5 an end clevation of such a hoist.

page_text: As in the arrangement already described a, a, are columns; b, a
platform; c and c¹, two cages or carriers which now may be of equal
weight, they are connected by a chain passing over the large chain
wheel & which is fastened upon the shaft e; fis the framing supporting
the shaft e; h, h, and h², h, are two hydraulic cylinders and rams;
k, k¹, arc chains fixed to the rams and passing over guide pulleys / to
the wheels m and m¹ respectively; these wheels are able to turn freely
upon the shaft e. n and n¹ are other chains leading over guide pulleys o
and o' to weights which are sufficiently heavy to keep the chains kand k'
constantly taut; p, p¹, are clutches by which either the wheel m or the
wheel m' can be made fast with the shaft e and the wheel d; q, q', arc
levers for working the clutches, they are connected, as is shown, to
the piston rod of a small water cylinder, and when one of the rams
comes to its highest position it touches a tappet Q and moves the valve
of the water cylinder, and so the clutch is thrown in which couples this
ram (through the intermediate parts already described) with the cage to
be lifted; is a lever for working the valve of the ram cylinders / and
by it the cages are started, the cage ascending when the opening of the
escape valve allows the water or liquid to escape from beneath the ram
which has previously been raised; at the same time that the loaded
cage ascends the unloaded cage descends. The same motion of the
lever which opens the passage for the water into one ram cylinder
causes the water or liquid pumped by the engine to be directed into the
other ram cylinder, so that one ram commences to ascend at the same
time that the other starts upon its descent.
The speed of the cages is controlled by the valve regulating the escape
of the water from the ram cylinder. s is a rod or bolt worked by the
lever r, and on the bottom of the cage there are hooks which catch over
this bolt and so prevent the cage ascending until the bolt is drawn back
out of the grip of the hooks, and this is done by the same motion of the;
lever which places the valve so as to allow of the escape of the water
from beneath the elevated ram and admits it beneath the other ram
which is then in its lowest position. There are two bolts 8, one for
each cage, and they are both worked from the lever r, or the cages may
be bolted and released in any other convenient manner.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that what I
claim is.

page_text: The construction of hydraulic hoists with a cage or carrier which
can be coupled with and uncoupled from an hydraulic ram in such
manner that the cage or carrier having been drawn up by the descent
of the ram it can then be retained and allowed to descend at any time
independently of the ram, substantially as described.
THOMAS WRIGHTSON. (L.S.)