Improvements in Fluid-pressure Machines, Specially Applicable to Elevators
Year: 1888

page_text: Improvements in Fluid-pressure Machines, Specially Applicable to
Elevators
1, JAMES LAWRENOE, of Chiswich, near Sydney, in the Colony of New South
Wales, 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 has reference to the application of differential hydraulic steam or
compressed ur power in machine which occupies comparatively small spice, 1s
simple in construction and working, and more economical in use than others heretofore
designed By its use, elevators, cranes, hoists or other power-machines may be con-
structed in which a comparatively small power is av ulable for one purpose, whilst in
increased power, capable of performing a much greiter task, is also at hind
My improvenients consist essentially in so constructing machines of the kind
hereinbefore referred to that each end of a ram may be used as in area to which the
power or pressure may be applied for acting in the same direction, and so that the
pressure may be applied to one such aren ilone or the two areas collectively, and they
further consist in the peculiar constructions and novel combinations and arrangements
of parts hereinafter more particularly set forth
In order that my invention may be clearly understood, reference will now be mide
to the accompanying drawings, whereof Figure 1 is an end elevation and Figure 2.
longitudinal section of a multiplying hydraulic elevator constructed according to my
invention
A 15 1 cylinder of cast iron or other metal, but preferably of solid-drawn steel or
wrought iron tube, the ends bung closed by screwed cips One of the latter is
formed is stuffing-box B, the other cip J is provided with brickets for callying
multiplying sheaves D is a rain or tube, preferably of solid-drawn steel or wrought
iron, one end of which is closed by a cap J₁, formed as a sheave-bi icket
The other
end of the tube D is fitted with a head or blank F in which there is recess for the
collar F, a plate E' keeping the collar F¹ in place E is a hollow rod fixed in the
raised boss Land being in communication with the port P and with the end M of the
ram D
E' is a pipe communicating between the interior of the rain D and the
atmosphere G is a piston fixed on the hollow rod E and provided with a leather
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page_text: packing G¹ The controlling valve is a three-ported valve having two inlet poits and
one exhaust port, and may be either of the slide or the piston type, and may be
worked by rack and pinion and grooved wheel and spindle, or by any other convenient
means
When using the lower power for lifting an empty cage or a light load, the pressure
is admitted to the end M'and acts between the piston G and the inner face of the
cap J', causing the ram D to move outward in respect of the cylinder A Should,
however, the power be insufficient, then, by further opening the controlling valve, the
second port P¹ is opened and the fluid under pressure allowed to gain access to
the cylinder A and to act upon the bottom F of the ram D, thereby augmenting the
lifting power
The water or other fluid under pressure acting on both ends F and
J¹ of the ram D, the full power due to the pressure exerted on these areas collectively
is utilised Thus, when there is only a light load, or the empty cage alone requires
to be raised, the smaller area of the inner face of the head J¹ is operative, and
approximately half the quantity of water or other fluid under pressure is consumed as
compared with the quintity employed when the total area of the two operative
surfaces before referred to is utilised In other words, when light load has to be
raised saving of fifty per centum of water or thereabouts is effected relatively to
hydraulic elevators and similar fluid-pressure machines in which the same lifting
power is used whether a light load or a heavy load be dealt with As an elevator in
use is generally required to iscend with considerably less than the maximum load it is
capable of lifting an important economy may be effected by the use of a machine
constructed according to my invention
I would have it understood that I have shown and illustrated what I deem to be
one of the most serviceable forms of my invention, and that I do not confine myself
to any precise source of power nor to the precise way shown and described of carrying
my said improvements into practice, as the nature of the invention is such that its
practical benefits may be obtained in ways requiring no further suggestions to the
mechanical mind For instance, the ram might be fixture and the cylinder might
be the moving body The principle is easily applied to direct-acting elevators and
cranes and to all kinds of machinery in which economical hydraulic, steam or com-
pressed air power is required
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed, I cl um in respect of elevators, cranes,
hoists and like machines operated by fluid under pressure
First The improved method of construction, substantially as herein described,
-whereby-one-or-both_ends_of_the_ram_may_be_subjected_to_pressure_in_the_sɩme.
duection
Second The improved arrangement, substantially as herein described, in which a
hollow rod supports a fixed piston within a hollow ram, part of the fluid under
pressure flowing when requisite through the hollow rod to the space between the
piston and the corresponding end of the ran
Third The improved arrangement, substantially as set forth, consisting of a fixed
cylinder in which is packed a hollow ram surrounding a fixed piston to form an extra
and independent pressure cylinder
Fourth The particular combination and arrangement of parts for forming a
multiplying hydraulic elevator, substantially as herein described and explained, and as
illustrated in the drawings