An Improvement in Manhole-covers for Sewer Ventilating Shafts.
Year: 1890

page_text: De of Application, 17th Feb., 1890
Complete Specification Left. 15th Nov., 1890--Accepted, 20th Dec., 1890
PROVISIONAL SPECIFICATION.
An Improvement in Manhole-covers for Sewer Ventilating Shafts.
1, FREDERICK BIRD of 11, Great Castle Street, Regent Street, London, W.,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved manhole cover for sewer ventilating shafts
or openings of that kind in which the cover is in the form of a grating or otherwise
provided with apertures for permitting of the escape of the sewer gas.
The object of the invention is to provide a ready means of closing these apertures
(when the ventilation through the manhole cover is not required) without necessitating
for that purpose the removal of the manhole cover from its seat.
According to my invention, I hinge to the underside of the manhole cover a pair of
semi-circular flaps or plates which may either hang vertically beneath the diametrical
line of the cover, so as not to obstruct the passage of the gases therethrough, or be
drawn up to a horizontal position against the underside of the cover (by means of a
hooked rod or other instrument inserted through the cover from above) so as to close
the apertures and be there secured by means of a button or other fastening device
engaging with the cover.
Dated this 17th day of February 1890.
COMPLETE SPECIFICATION.
An Improvement in Manhole-covers for Sewer Ventilating Shafts.
I, FREDERICK BIRD of 11, Great Castle Street, Regent Street, London, W.
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 :-
My invention relates to an improvement in covers for sewer ventilating shafts
or openings of that kind in which the cover is in the form of a grating or otherwise
provided with apertures for permitting the escape of the sewer gas.
The object of the invention is to provide a ready means of opening or closing these
apertures at will without necessitating for that purpose, the removal of the cover from
its seat, so that in the event of objections being raised to the escape of the sewer gas
at any particular cover, its apertures may be closed and the gas forced to escape at
some less objectionable locality.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figure 1 is a vertical section of a manhole cover in its seat over a shaft, the
apertures of the cover being open.
Figure 2 is a plan of same, and
Figure 3 is a similar section to Figure 1 shewing the mode of closing the
apertures.
The same letters of reference indicate like parts in all the figures.
According to my invention, I hinge at 6 to the underside of the manhole cover A
a pair of semi-circular flaps or plates B B which may either hang vertically beneath
the diametrical line of the cover, as in Figure 1, so as not to obstruct the passage of
the gases through the apertures in the cover, or be drawn up to a horizontal position
against the underside of the cover (by means of a hooked rod C or other instrument

page_text: inserted through the cover from above, as shewn in Figure 3) so as to close the
apertures and be there secured by means of a turn button D or other fastening device
engaging with notches in the bars of the cover. The turn button D has an eye into
which the hook C is engaged both for lifting the flap and for turning the batton (when
the flap is raised) into position of engagement with the notches d.
The flaps B would of course correspond in form and dimensions to the area of the
cover in which the apertures to be closed are situated. For instance, the cover may
be wholly a grating the apertures being parallel, as in Figure 2, or the central portion
only may have concentric annular apertures, the outer part of the cover being faced
with wood blocks.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
The combination, with a cover for sewer shafts, of a pair of flaps hinged to the
under side of the cover and adapted either to hang down or to be drawn up against
the cover and provided with turn buttons or equivalent means of fastening them in
the raised position, subsequently as specified.
Dated this 15th day of Nova b. 1900
By A. M. & Wm. Clark,
F. BIRD.
53, Chancery Lane, London, Patent Agents.