Improvements in Inner Man-hole Covers and the Means of Looking them Down.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Inner Man-hole Covers and the Means of Looking
them Down.
JOHN SMEATON C.E. 56 Great Queen Street W.C. in the County of London
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 :-
more
This invention consists of an inner cover for manholes, provided with means for
fastening it down and so constructed as to present a large surface to
effectually condense the vapors arising from drains, sewers or the like and to cause
the water of condensation to drain to the edge and thence into the lute joint pro-
vided for the reception of a flange-like lip which forms an integral part of the
cover and is situated at its edge.
To effect this the cover is provided with a series of angular corrugations, the
tops of said corrugations being in a horizontal plane at the top of said cover and
the bottoms inclining from the centre downwards towards the edge, where they are
terminated by the flange-like lip.
It will be understood that as the water of condensation collects on the sides or
tops of the corrugations it will gravitate to the bottom of said corrugations and as
the bottoms of these are also inclined it will then find its way to the edge as far
as the lip and thence into the lute-joint.
I am aware that a manhole cover has been constructed on the principle of a
bell trap, the water of condensation trickling down the domed interior into the
lute joint, but I claim the advantage of a larger superficial area than this affords
with a given height and therefore larger condensation which insures the lute
joint being kept full of water and no possibility of the escape of noxious gases.
On the top of the said cover and at its centre two ears are provided, between
which the ends of two locking bars are situated, each of said ends being provided
with a slot slanting down in opposite directions; one bar is provided with a lug
which over-laps its fellow and a cam, which is engaged by the cranked end of a pin
about which the slots operate and which is journalled in the ears attached
to the cover and is prevented from being withdrawn by means of a washer and
cotter.
Each of the locking bars is provided with a fulcral point situated at about its
centre, which rests on the top of the corrugation over which it is situated.
When the cover is being supported by means of the handles, with which each
locking bar is provided, its weight will cause the pin to travel down the slots in
said locking bars thereby causing them to be drawn in, but when said cover is
otherwise supported the weight of the bars causes them to travel down and out by
virtue of their slots engaging the said pin until their fulcra rest on the cover, if,
when in this position, the cranked end of the pin, which engages the cam on one
of the locking bars, be turned a quarter of a revolution it will cause the inner
ends of the locking-bars to be depressed and the outer ends to be raised and so
lock the cover down.
The cover has a flanged edge outside the lip before referred to, under which,
when I think it necessary, I place a gasket of rubber or other suitable material.
The accompanying drawings illustrate my invention thus:-
Fig. 1. is a vertical section through a manhole showing the inner cover in partial
elevation with locking device.
Dowlan wines of the innAY MADAN with Lobine dovine

page_text: Figs. 4, 5 and 6 are views of parts of the locking device, showing same
when the locking bars are respectively, disengaged, engaged with and locked over
manhole.
Fig. 7. is a detail of the left hand locking bar.
Fig. 8. is a detail of the right hand locking bar.
Fig. 9. is a plan view of the end of the locking bar shown in Fig. 7.
Fig. 10. is a detail of pin showing its cranked end.
Figs. 11 & 12. show respectively a front and edge view of the key lever with
which the cranked pin is turned to effect the locking down of the cover.
Like symbols of reference indicate like parts in each.
When it is desired to place my cover over the manhole it is lifted by means of
the handles D¹ & E', the weight of said cover causing the pin F, which is journalled
in the ears H, to travel down the slots d¹ & e¹ of the locking bars D & E and
forcing them to be drawn in and their inner ends to occupy the position shown in
Fig. 4.
It is then placed over the manhole, the flange-like lip bentering the channel a¹ of
the lute joint and the flanged edge 61 resting on a gasket g which is placed on the
ledge a² that surrounds the interior of the manhole.
When in this position the handles D' & E' are allowed to fall and the locking
bars D & E, whose weight causes them to travel down and outwards by virtue of
their slots d¹ & e¹ sliding on the pin F until their fulcra d & e rest on the top of
the cover, their outer ends enter the recesses "a" formed in the manhole A and
their inner ends assume the position illustrated in Fig. 5., the key lever G is then
applied to the cranked end of the pin F, the pin entering a suitable hole / in
the end of the pin F & one of the two projections 9 engaging each side of the
crank F, pressure is then applied in the direction of the arrow (see Fig. 5) until
the cranked end passes the vertical line as shown in Figs. 1, 2 & 6 the first showing
the key lever in dotted lines.
When the pressure is applied to the cranked end F' of the pin F, an inwardly
projecting finger f, seen best in Figs. 2 & 10, is made to engage the cam J, and as
its movement is continued it forces the said cam and the end of the locking-bar D,
which carries it, down from the position it occupies in Fig. 5. to that in Fig. 6.
The locking bar D has a lug L (see Fig. 9.) cast on the opposite of it to that
occupied by the cam J, which presses on the other locking bar, E, and causes its
inner end to descend when D does, thus, by turning the crank-ended pin F a full
quarter revolution the inner ends of the locking bars D & E are depressed, and, as
their fulcra d & e already rest upon the top of the cover, their outer ends are raised
against the top of the recess a, which, being solid, obliges the cover to be forced
down and to compress the gasket g.
The pressure may be regulated by means of an adjustable pin which is shown in
dotted lines in Fig. 10.
The cover which I have illustrated is, of rectangular shape but, it will be under-
stood, may be of any convenient shape.
It is provided with a flange-like lip b, which enters a channel a¹ and forms a
lute joint, and a flanged edge 61 under which, when necessary, I place a
gasket g.
The top of the cover consists of a series of corrugations M, the tops, m, of
which are preferably in the horizontal plane, but whose outer ends, o, must not be
higher than their inner ends "n" and the bottoms, p, of which incline downwards
to their outer ends.
When the vapor rises, the condensation is deposited uniformly over the interior
of cover, that which is deposited at the point m, or top of a corrugation will roll
to the nearest point p, or bottom of a corrugation, whence it will roll down the
inclined bottom until it reaches the flange-like lip 6 whereafter it finds its way to
the lute joint which it keeps filled with liquid.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A manhole cover provided with a corrugated top so constructed as to present
as large a surface as possible, for the condensation of vapors arising from sewers,
drains, or the like and to convey the water of condensation to the edge and thence
into a lute joint.
2. A locking down device consisting of two locking bars provided at their inner
ends with slots slanting in opposite directions and operating about a pin whose
cranked end carries a finger or projection which operates upon a cam attached to
one of the locking bars, said locking bar having also a lug attached to it which
bears upon the inner end of the other locking bar and constrains it to move down-
wards when it is itself moved in that direction, as described and for the purposes
set forth in the Specification.
3. In combination with a manhole cover, a locking down device of the con-
struction described in the Specification and for the purposes therein set forth.
Dated this 6th day of January 1892.
JOHN SMEATON.