IMPROVEMENTS IN MACHINERY OR APPARATUS FOR RAISING AND LOWERING HEAVY BODIES
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by John Campbell Evans and William
Fairlie at the Office of the Commissioners of Patents, with their Petition,
on the 5th September 1865.
We, JOHN CAMPBELL EVANS and WILLIAM FAIRLIE, of the Morden Iron
Works, East Greenwich, in the County of Kent, Engineers, do hereby declare
the nature of our said Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS
FOR RAISING AND LOWERING HEAVY BODIES," to be as follows:-
Our Invention relates to certain peculiar combinations and constructions of
fixed or transportable direct-acting double-action steam, air, gas, or hydraulic
apparatus for raising and lowering heavy bodies, which is more especially
applicable to the discharging of the cargoes from the holds of ships.
According to one mode of carrying out our Invention.we propose to employ
a stationary steam cylinder placed either horizontally or at any desired angle.
Within this-cylinder-works-a-piston-and piston rod passing through a stuffing
box in one end thereof. The outer end of the piston rod carries two or more
sets of pullies, over which and round corresponding sets of fixed pullies
separate ropes are passed, which are theu carried up to the ordinary over-head
guide pullies. Whilst the piston is moving in one direction one or more sets
of ropes are lifted and the others simultaneously lowered, so that in unloading
a ship, for example, the full baskets are being raised whilst the empty ones
are lowered, and when the piston reverses its motion the ropes which had
previously been lowered are lifted, and so on. The valve for the cylinder may
be the ordinary D slide valve; it is worked by a tappet which is acted on at
or about the. end of each stroke by the piston rod so as to close the valve and

page_text: stop the machine whilst the baskets are being respectively filled and emptied.
As the beight of the lift varies the traverse of the piston should also and
vary,
in order to avoid waste of steam we propose to regulate or vary the effective
length of the cylinder by means of a sliding trunk, which is caused to slide a
greater or less distance inside the cylinder and form the end of the same.
According to another arrangement we propose to employ a longitudinally
reciprocating cylinder sliding on a bed or in guides, and to dispense with the
sliding trunk, using in lieu thereof two pistons on one rod, which rod passes
through a stuffing box in each end of the cylinder. This rod is stationary
aud has a right and left handed screw made thereon, so that on turning the
same the pistons will be caused to approach towards or recede from each
other and thereby vary the effective length of the cylinder. The sets of
moveable pullies are carried by the cylinder itself, and the corresponding fixed
pullies are secured to the framing in such a manner, that one weight or set of
weights is lifted whilst the other is lowered, and vice versa, at each stroke or
traverse of the cylinder. The steam is admitted to each end of the cylinder
alternately through trunks which surround the piston rod and which are
severally secured to the pistons, or through the piston rod itself, which may
be made hollow for that purpose. These trunks or hollow piston rods com-
imunicate at their outer ends with corresponding steam chests and slide valves
worked by tappets from the cylinder, the position of these tappets being made
adjustable according to the length of stroke desired.
According to another modification, in lieu of admitting the steam to the
cylinder through the hollow piston rod, or through trunks, it may be supplied
thereto from a single steam chest formed on the reciprocating cylinder itself,
to which steam chest the steain is admitted by a steam pipe, along which the
steam chest slides to and fro with the cylinder. If desired, the piston rod may
only work through one end of the cylinder, in which case a closed tronk or
cap may be fitted to or formed on one of the covers for the end of the piston
rod, to work in. The valve, which may be either a piston valve or a D slide,
is acted upon by means of tappets, the positions of which are varied simul
taneously with the alteration of the pistons by means of a screwed tappet
shaft, so that their positions must necessarily agree with those of the pistons:
The object of thése táppets is to close the steam ports and arrest the move-
ment of the machine after each stroke, so as to afford time for attaching the
load to be lifted. The machine is started again by the action of a crank or
eccentrix upon tail pieces attached to the tappets. This crank imparts a
partial rotatory motion to the tappets on their rod, and as the tappets are
bevilled or inclined on their acting surface this partial revolution will move

page_text: the valve sufficiently forward or backward, as the case may be, to open one or
other of the two steam ports and so start the machine again. This starting
of the machine for either front or back stroke is effected by simply pulling a
string or rod which is attached to a counter-balanced lever on the crank shaft.
The apparatus being thus arranged the valve is moved and the motion of the
machine reversed at each successive pull of the string or rod in the same
direction.
In some cases we propose to bring the piston rods of the two adjustable
pistons through one and the same end of the cylinder, the rod of one piston
working through the other piston. In this arrangement the adjustment of the
pistons may be effected either by screw threads on the rods or by simply
sliding the rods through the cylinder cover.
Either of the above-described modifications of our apparatus for raising and
lowering heavy bodies may, if intended to be worked by steam, be fixed on or
attached to a convenient boiler so as to form an apparatus complete in itself,
and which may be readily placed on board the vessel or in the situation where
it is required to be used and removed again when the work is finished.