Improvements in Lifts.
Year: 1893

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by die Firma FRIED. KRUPP, Grusonwerk, of
Magdeburg-Buckau, in the Empire of Germany, Manufacturers.]
Improvements in Lifts.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 improvements in lifts and has for its object the con-
struction of a hydrostatic lift for effecting the transfer of navigable vessels between
canals or other waters at different levels. The said improved lift is operated by
It is based on the same
simple means and with but a small expenditure of energy.
mechanical principle as that of the pendulum.
In order that the nature of the said invention may be clearly understood it will
now be described with reference to the accompanying drawings, in which
Figure 1 is a longitudinal central section of an improved hydrostatic lift
constructed according to this invention, and
Figure 2 is a transverse section of the said lift on the line ax of Figure 1.
Similar reference letters indicate corresponding parts, throughout the drawings.
A is a trough designed for the reception of the vessel or vessels and arranged to
rise and fall between suitable guides as hereinafter described. The said trough
is adapted to be filled to a proper depth with water and is provided with suitable
water-tight gates at its ends A. This trough is supported upon standards B, which
rest upon floats C. The latter are submerged in wells or chambers D which
communicate with each other. E is the higher canal and F the lower canal.
of the said canals are provided with water-tight gates which, with the gates on the
trough, control communication between the canals and the trough in the manner
hereinafter set forth. The depth of the water in the wells or chambers D is so
adjusted that the trough A does not dip thereinto even when the said trough is in
its lowest position.
Both
In such lifting apparatus it is an indispensable condition that the trough, during
its ascent and descent, be controlled in such a manner that it shall always maintain
a horizontal position. In the present example this is achieved by the means now
to be described :-Four vertical racks J are firmly secured to guide standards M
suitably supported upon the foundations of the structure. Four spur-wheels K,
secured to horizontal shafts L supported in bearings on the side of the trough A,
engage with the said racks and are geared to each other by the said shaft L the
vertical shafts N and the horizontal shaft O and suitable gear wheels fixed on the
said shafts. The said spur wheels K are prevented by the aforesaid gearing from
rotating otherwise than at equal velocity, so that the four points on the trough at
which the said wheels are situated are compelled to move simultaneously and
at equal speeds and thus the trough is kept horizontal. Upon the shaft O is
arranged a brake or locking device of a suitable character by means of which the
toothed wheels K are prevented from turning and can be caused to stop the trough
at any point in its travel. The principle upon which the operation of the lift is
based, and the manner in which it is operated will now be described.
If the height of the water-level of the upper canal E above that of the lower
canal F is designated by H, the buoyancy of the system consisting of the trough A
the standards B and the floats C, is so balanced by the weight of water in the
trough A that the said system will be in equilibrium when the water level of the
trough is exactly midway between that of the upper canal and that of the lower
canal, that is to say, at a distance from either which is represented by the

page_text: fraction
H
2
In this case it is immaterial whether a large or small laden or light
vessel or no vessel at all is in the trough, provided only that the water in the
trough is at the same level in any of such instances.
H
2°
Let it be supposed that the said system is moved downward from this position of
equilibrium so that the surface of the water in the trough comes to the same level
as that of the canal F, and that the system is held in its new position. Then there
will no longer be equilibrium between the buoyancy and the weight of the system.
but the former will exceed the latter by the weight of the quantity of water
displaced by the increased immersion of the standards B which are deeper in the
water by the distance represented as aforesaid by Accordingly the system if it
be now released, will have a tendency to rise again, the motive power being the said.
H
excess buoyancy, proportionate in the present instance to
fis taken to
indicate the total sectional area of the standards B, the said excess of buoyancy
diminishing in proportion as the standards rise out of the water again, and
disappearing altogether when the trough regains the said position of equilibrium.
This gradually decreasing motive power imparts to the mass of the system, which
remains constant, an increasing velocity with a diminishing acceleration the former
becoming a maximum at the aforesaid midway point.
Arrived at the said point the system has acquired momentum which moves it still
further upward, but at a diminishing velocity, because the standards B move further
and further out of the water in the wells or chambers D and the buoyancy of the
system therefore diminishes. The preponderance of the weight of the system
f)
F H
2
over its decreasing buoyancy is proportionate to when the trough has risen so
far that the surface of the water therein arrives at the same level as that of the
water in the upper canal, and when the said surfaces are thus coincident the:
momentum of the system is entirely expended. The trough, therefore, at its
highest position has no velocity, and would immediately return downward like a
stone thrown up into the air, or like a pendulum which has reached the highest
point of its vibration, if it were not held. The retention of the system in its
highest position, when its momentum is nil, is easily effected by applying the brake
to prevent the rotation of the spur wheels K.
The trough when it arrives at its highest position is placed in water-tight
connection with the end of the upper canal and after the gates of the canal end and
of the trough are opened a ship raised by the trough can move into the canal, or a
ship to be lowered from the latter can move into the trough.
After the gates have been closed again the system is liberated by disengaging
the brake or locking device, and it sinks at an increasing velocity to the middle
position, and thence, by overcoming the increasing buoyancy, at a decreasing
velocity to the lowest position, in which it arrives with no velocity. Here the
brake is again applied or the locking device engaged, and the trough held so that
ships may pass between it and the lower canal. From the foregoing it will be
seen that the mode of operation of the apparatus is based upon the movement
of the system about the middle position of equilibrium to the two limits of the
amplitude of its oscillation, that is to say, the surface level of the lower and of the
upper canal, and the movement of the system is imparted thereto by the excess
buoyancy possessed by the system when it is below the said middle position
and by the excess of the weight of the system over its buoyancy when it is above
the said middle position.
Theoretically the apparatus would not require the expenditure of energy either
for the raising or for the lowering of the same, but as in practice as frictional
resistances exist, such as the resistances in the water, in the air and in the guides,
which may be assumed as constant, the trough will have to be loaded a little more

page_text: in its upper position and a little less in its lower position. This may readily be
accomplished by fixing the trough, before the system has completely reached its
limits of oscillation. In the highest position a little water always flows into the
trough from the upper canal, which water, in the lowest position of the trough,
flows off into the lower canal.
Should the water level of the upper or lower canal change, this circumstance
may be taken into account in a simple manner in the case of the described
apparatus. The position of equilibrium of the system then requires only to be
placed somewhat higher or lower, in order that the lift may continue to act properly,.
and this may be attained by a slight change in the quantity of water in the
trough.
Having now particularly described and ascertained the nature of the said inven--
tion and in what manner the same is to be performed, as communicated to.
me by my foreign correspondents, I declare that what I claim is
1. A lifting trough supported upon floats and arranged to oscillate about a point-
between the upper and lower limits of its travel, which trough possesses besides the
customary parts for guiding it straight, a brake or locking device by which the
system is held at the terminal points of its travel.
2. A rising and falling system comprising a trough and submerged attachments,.
constructed and arranged in such a manner that the weight of the system is less
than its buoyancy at the lower limit of its travel, equal to its buoyancy at an
intermediate point of its travel, and greater than its buoyancy at the upper limit of
its travel, in combination with means for retaining the said system at either extreme
of its travel, substantially as herein before described, for the purpose specified.
3. The improved hydrostatic lift constructed substantially as hereinbefore.
described with reference to the accompanying drawings, for the purpose specified.
D
this Oth dor of September 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.