IMPROVEMENTS IN LOCKS AND LOCK GATES FOR CANALS, DOCKS, HARBOURS, AND NAVIGABLE RIVERS
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the Office
of the Commissioners of Patents on the 20th May 1879. A communication
from abroad by James Pouchet and Gustave Sautereau, both of Paris, France.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN LOCKS AND LOCK GATES FOR CANALS, DOCKS,
HARBOURS, AND NAVIGABLE RIVERS." [A communication from abroad by James
Pouchet, and Gustave Sautereau, both of Paris, France.]
This Invention relates to the construction and arrangement of locks used in
canal and river navigation, the improvements being applicable to existing locks,
although they are more especially designed to enable a far greater lift to be
obtained with a single lock than has ever hitherto been possible. I will proceed
to describe how, by its means, one single lock may be made to supersede the series
of 7, 8, 10, or 12 ordinary locks, placed either close together or at a distance apart,
which it has been considered necessary for the navigation of a proposed ship canal
to connect the Lake of Nicaragua with the adjoining oceans, between whose mean
level and that of the lake there is a difference of 32 metres 80 c.
A ship canal lock of this kind should be of about the following dimensions ;
length of lock chamber 200 meters; breadth of gates 20 metres; mean lift 32
metres 80 c.; mean depth of water on the tail sill 8 metres 25 c.
.
In this improved canal lock, the ordinary hinged pair of gates or caissons are
replaced by a single leaf or door, having a smooth sliding or rolling rectilinear to
and fro motion. This arrangement is the only one which will admit of a con-
siderable lift being obtained, and involves the use of a lateral chamber, herein
termed the door chamber, in which the door is withdrawn to give passage to
vessels.
The Invention is illustrated in the accompanying Drawings, in which Figure 1
is a longitudinal vertical section of a canal lock; Figure 2, a plan thereof; and
Figure 3, a transverse section partly on the line C, D, and partly on line E, F, of
Figure 2; Figure 4 is a transverse section of the tail gate taken on line G, H,
Figure 2; Figure 5 is a transverse section of the lock taken on line A, B, Figure 2,
showing the large tail gate closed. Figures 6 and 7 are longitudinal and transverse
sections on a larger scale of the upper part of the tail gate with its girder guide.
Figures 8 and 9 are longitudinal and transverse sections of the tail gate with its
slides (which are of the kind known in France as the Système Girard). Figure 10
is a horizontal section of same taken on line M, N, Figure 8. The same letters
and figures of reference indicate the same parts in all the Figures.
The general arrangement of the canal lock is that represented in Figures 1 and 2.
Commencing at the tail end, there is a tail bay a, quays b, b, windlasses c, and

page_text: capstans d for towing vessels into the lock. The tail bay a has recesses e, e, for
damming out the water when repairing the lock. The Drawings show only one
large tail gate f, but it will be understood that several may be employed so as to
divide the lift, and this forms one feature of the Invention. In some cases a single
gate might have to be of excessively large dimensions, and by employing a second
tail gate the lift would be halved, making it, in the case taken as an example,
16 metres 40 c.
A considerable reduction in the dimensions of the apparatus is thus effected,
and by employing three tail gates making three lifts of about 11 metres each, the
apparatus may be still further reduced in size, and the lift would be less than that
of some large canal locks of the ordinary construction. Thus by providing a canal
lock with one, two, three, or more tail gates, one lift of 33 metres, or two lifts of
161, metres, or three of 11 metres, may be obtained in the same lock.
It has however been found by calculation that, for a total lift of 32 metres 80 c.,
a gate constructed of steel plate and having a high factor of safety would be of such
practicable dimensions that a single tail gate is confidently specified for the
example taken.
Figures 1 and 2 show that the bead gate g, although of ordinary dimensions, is
arranged and operated in a similar manner to the large tail gate f. On the
opposite side to the gate chambers there are small chambers or recesses i to
receive the leading edges of the gates when the lock chamber j is closed.
The gate
chambers are large enough to completely contain the gates within them, and
admit of being closed to forin.dry docks when fixing or repairing the gates. Vis
the head bay; and the quays at either side. In the side walls of the lock
chamber are two large culverts m, m, see Figures 1, 2, 3, and 5, from which branch
others n, n, normal to the longitudinal axis of the lock and placed on a level with
the floor of the lock chamber, and establishing communication between the lock
chamber and the tail or head bays. These main and branch culverts may be con-
structed of masonry lined with hydraulic cement, but in this example they are
supposed to be cast iron pipes laid in subways so as to be easy of access for repairs,
thus avoiding all liability of leakage through defects in the masonry. The branch
culverts n, n, are accessible to within a short distance of the face of the side walls
of the lock chamber, where the subways are closed by brickwork. The whole
system of subways are laid at a suitable gradient, and provided with means for
extracting any water leaking from the pipe joints. The main culverts m, m, are
each connected with wells o containing sluice valves p, p, to which access is had
from the quay for filling and emptying the lock, or for affording a bye passage for
the water from the head to the tail bay without passing through the lock. These
sluice gates are of metal and are counterbalanced against the pressure of water at
the back by water forced in between the sluice gates, and the grooves or guide
ways in which they slide, whereby the power required to work them under the
pressure due to the head of water and their large area is considerably reduced.
The areas of the main and branch sluices are calculated to fill or empty the lock in
15 minutes.
The above arrangements which are adapted to a canal lock of the exceptional
kind herein described may be simplified when applied to locks whose lift is less.
The axis of the chamber his arranged at an angle of about 80° to that of the lock
chamber, so that by bevelling the contact surfaces T at an angle of 10° to the gate
they will be perpendicular to the axis of the lock, and the resultant of the pressures
upon the masonry will also be parallel to the said axis.
For a canal lock of the exceptional size described, the gates should be operated
by bydraulic power, for which purpose either one of the two following arrangements
may be adopted, viz., a head of water from above the lock driving a series of water
wheels or turbines which work pumps for supplying water to reservoirs on the lock
quay, whence it is distributed to the several hydraulic windlasses or motors for
working the gates, sluice valves, &c. Or a head of water above the lock and
hydraulic motors working accumulators, by which water is supplied under considerable

page_text: pressure for working the apparatus without employing reservoirs. The adoption
of one or other of these arrangements is dependent on the size of lock.
I will next describe a mode of mooring vessels to be employed with a canal lock
of this construction. Suppose a windlass to be placed at the edge of the lock quay
to which a mooring cable is led from the vessel. This cable when the lock is full,
i.e., when the water is at its highest level, extends upwards to the vessel at an
angle of about 45°, and as the lock empties and the vessel is lowered, this angle
becomes reduced until the cable passes below the horizontal plane, the slack of the
cable being meanwhile taken up, after which the cable is again payed out until the
vessel reaches the lower level. With reference to this part of the Invention, the
improvement consists in replacing the ordinary bollards or bitts which are
inapplicable in this case by windlasses of special construction, whereby the cable
is kept at a constant tension at all times.
The Invention also includes the following arrangement in connection with the
mooring of vessels, illustrated in Figures 1, 2, 3, 4. In each side wall of the lock,
at opposite points, four vertical recesses or chambers 8, 8, are formed in the masonry,
eight in all, which number however may be varied according to the dimensions of
the lock chamber. Vertical iron guides are embedded in the walls of these
chambers, upon which work cylindrical pontoons or floats t having a considerable
draught of water, and upon their decks are fixed the bitts for the moving cables.
The deck of the float when the lock is full is at the same level as the lock quay.
The floats are provided at top and bottom with three pairs of guide rollers having
the requisite amount of play so as to prevent jamming, while at same time
retaining the floats in their guides and allowing of their rise and fall with the
vessel as the level of the water in the lock varies. Thus the cable by which the
vessel is moored to the float never requires to be lengthened, as the relative
positions of the vessel and float always remain the same whilst locking.
In order to allow the cables to extend in an oblique fore and aft direction when
the side walls of the lock are battered, the vertical lateral walls of the float
chambers have a gradual downwardly increasing splay to meet the side walls of
the lock. The lock gate has been briefly described as being single, and having a
sliding or rolling rectilinear Inovement to and fro.
The gate is made in the form of a rectangular parallelopiped, and for a lock, such
as that described, the large tail gate would be of about 40 metres in height,
26 metres in width, and 7 metres in thickness. This construction is preferable to
all others, both from an economical and practical point of view. The gate shown
in Figures 4, 5, 6, 7, 8, 9, and 10, is constructed of horizontal lattice girders, super-
posed at distances of one metre apart. The general dimensions are uniformn, the
thickness of metal alone being varied according to the head of water to be supported.
In order to ensure the watertight closure of the lock when the gate is closed, two
contact faces u are each bevelled or skewed to an angle of 10° (see Figure 10)
throughout their height, and for a breadth of 3 metres these bevelled faces enable
the gate to slide freely to and fro, and when closed to make a tight joint by
coming against similarly bevelled seats or surfaces r of the same dimensions on the
side walls of the lock. Both u and rare faced with wood baulks or planks of
considerable thickness, so placed that their joints shall be contrary to the direction
of contact in closing, to which nevertheless the direction of the grain of the wood
should correspond. In case of wear or decay of any part of these wooden seats,
they can be readily renewed at any time. Possessing a certain amount of elasticity
they also serve as cushions to uniformly distribute the pressure of the water
transmitted to the walls by the gate. It has been before mentioned that the gate
and its chamber are both placed obliquely, in order that the contact faces shall be
perpendicular to the axis of the lock, and the thrust upon the walls be in the most
favorable direction. Moreover this system admits of attaining the greatest
possible security in this respect, by merely increasing the area of the contact
surfaces without making any change in the general arrangement.
The gate is drawn to and fro by means of chains attached to its base (see

page_text: Figure 5), and passing round large guide pulleys x upwards to the hydraulic wind-
lasses by which the chains are operated, the gate being opened or closed by hauling
on one chain and slacking out the other, and vice versa. When the gate is drawn
back into its recess the chain which passes across the lock is slacked out to allow
it to rest in a cast iron gutter or channel y, Figures 8 and 9, sunk in the floor of the
lock. In this manner the chain will be protected from damage even should the
vessel touch the bottom of the lock, in consequence of too great a draught astern.
The draw chains vare attached to a swivel z, Fig. 8, the stem of which is secured
by a metal disc or head, and between this and the cover of the box through which
the swivel passes thick india rubber cushions are introduced, possessing sufficient
elasticity to lessen the strain in starting and stopping, and thus avoid fracture.
If the gate be mounted upon wheels or rollers their number and diameter would
be proportionate to the dimensions and weight of the gate. The wheels or rollers
would run upon stone, concreted, or cast iron ways slightly flanged to form guides
for the gate. The arrangement shown in the Drawings is that preferred for a gate
of the largest dimensions. It consists in mounting the gate upon four skids or
shoes, on what is known in France as the Girard system, i.c., hollowed to contain
water forced in at a high pressure by which to slightly raise the gate before
starting it. The gate is further provided with an air chamber 2, at bottom
extending upwards for a height of about 4'/, metres from the floor of the lock.
Two cylindrical shafts 3, of about 1 metre in diameter, with an air chamber at top,
give access to the large bottom air chamber, so that it is possible even when the
gate is working to inspect the shoes and guideways. The gate, whether mounted
upon skids or rollers, would be provided at front and rear with large sheet or cast
iron scrapers 4 (see Figures 5, 8, 10), for keeping the guide ways free from stones or
matters deposited by the water. The gate is also provided upon the inner face
above the level of the air chamber with large apertures for the inlet and exit of
water, in order that it may be always sufficiently weighted to prevent its lifting
while the lock is being filled.
Another feature of the Invention consists in the girder guide 5, which is flush
with the top of the gate, and is about 60 metres in length, or sufficient to reach
across from the inner or back end of the gate chamber to the opposite side of the
lock, see Fig. 5.
it.
The object of the girder is to form a guide for the gate when closing and opening
When the gate is open the girder guide is withdrawn into a chamber forming
a continuation of the upper part of the gate chamber h, and in order to close the
gate the girder is first projected across the lock, until its end is received in a niche
made for its reception in the side wall at the upper part of the recess i. The
length of the girder is sufficient as above mentioned to enable this to be done, as it
runs upon the door until its end is received in the said niche, whilst its opposite
end always remains engaged in its chamber, and the girder is thus securely
retained in position at both ends. The gate is to be operated only after the girder
guide has been placed in position, and being thus held at foot by the skids in the
guideways, and at the top by the girder 5, it is retained securely in an upright
position.
By this means the gate may be closed even during a high wind, which would
otherwise be liable to upset it.
It will be unnecessary to withdraw the girder every time the lock is used as
many masted vessels can pass under it.