Improvements connected with Covers and Frames for Manholes and the like.
Year: 1892

page_text: Date of Application, 24th June, 1892-Accepted, 13th Aug., 1892
COMPLETE SPECIFICATION.
Improvements connected with Covers and Frames for Manholes
and the like.
I THOMAS CRAPPER, of the firm of Thomas Crapper and Company, of
Marlborough Works, Marlborough Road, Chelsea, in the County of Middlesex,
Sanitary 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 :—
The chief object of the present invention is to provide means for facilitating the
raising from their seats of covers for manholes and the like.
At the present time the raising of these covers is frequently attended with great
difficulty, since they are liable to rust in their frames, especially if they fit the same
closely. Now by the employment of my invention, the starting of the cover from
its seat can at all times be readily effected.
My invention consists in constructing manhole and like covers and frames with a
screw attachment or attachments, preferably situated upon opposite sides thereof,
so constructed and arranged as to tend to force the cover from its seat when turned
in the proper direction by a convenient key or wrench. I may also combine if
desired with the above mentioned cover raising attachments, means for securing the
cover in position within the frame as hereinafter described.
At
I will now proceed to describe a cover raising attachment which I have found
to answer well in practice. I construct the frame with a horizontally extending
lug or projection having a tapped hole therein with which engages the threaded
portion of a screw bolt provided with a square or polygonal head which passes up
through an aperture in a corresponding lug or projection formed on the cover.
the base of the square or polygonal head of the screw bolt is an encircling flange
or shoulder which bears against the underside of the said lug or projection on the
cover. Upon turning the screw bolt in the proper direction by means of a
convenient key applied to its square or polygonal head the cover will be forced
from its seat by means of the before mentioned encircling flange or shoulder.
When it is desired to secure the cover in position I may provide the head of the
before mentioned screw bolt with a tapped hole for the reception of a screw having
a broad head which bears upon the upper side of the lug or flange of the cover and
thus holds it down in place.
1
In the accompanying drawings in which similar letters refer to corresponding
parts in all the figures :-
Fig. 1, is a plan of so much of a manhole cover and frame, constructed in
accordance with my invention, as is necessary to illustrate the same.
Fig. 2, is a sectional elevation on line 1-2 Fig. 1.
a is the manhole cover and the frame. c is the usual dependent flange
extending around the cover a and fitting into the usual groove or channel d
extending around the frame b. e is a lug projecting horizontally from the exterior
of the frame and e¹ is a corresponding lug projecting horizontally from the
exterior of the cover a. is the threaded portion of a screw bolt which engages
with a tapped hole in the lug e, and is the square or polygonal head thereof
which passes up through the hole y in the lug e. f is an encircling flange or
shoulder at the base of the head which bears upou the underside of the cover a.
Upon turning the screw bolt in the proper direction by means of a key applied to
the head thereof the encircling flange f' will force the cover a from its seat in
the frame b. h (Fig. 2,) is a screw engaging with a tapped hole in the head f' of the
screw bolt, the head of this screw h bears upon the upper side of the lug e' and
holds the cover a in position. indicates a suitable slot in the head of the screw/

page_text: for the insertion of a key. When the holding screw his employed it must of
course be removed before the key can be applied to the head of the lifting
screw.
Although I have described, and illustrated in the accompanying drawings, the
cover raising attachment as placed outside the cover and frame it is obvious that
the same might be placed inside if preferred the lug e being in that case formed
inside the frame and the hole g being made in the cover a. I prefer however
the arrangement described and illustrated. It is equally obvious that the same
might be slightly varied in details without in any way departing from the spirit of
my invention as herein before set forth.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
'I claim is :-
1. The use in combination with a cover and frame for manholes and the like,
of a screw attachment forming a part thereof so arranged and constructed as to
tend to force the cover from its seat in the frame when rotated in the proper
direction by a suitable key, substantially as set forth.
2. A cover and frame for manholes and the like each provided with a horizontally
extending lug or projection between which lugs is interposed a flange or shoulder
encircling a screw bolt which engages with a tapped hole in one of the lugs
substantially as and for the purpose described.
3. In combination with a cover and frame for manholes and the like a screw
attachment for raising the covers from their seats, constructed and arranged
substantially as described with reference to and illustrated in the drawings.
4. In combination with a cover and frame for manholes and the like, screw
attachments for raising the cover from its seat and for holding it in place within the
frame if desired, constructed and arranged substantially as described with reference
to and illustrated in Fig. 2 of the drawings.
Dated this 22nd day of June 1892.
E. P. ALEXANDER & SON, Fels. Char.d. Inst. P.A.,
19, Southampton Buildings, London, W., Agents.