IMPROVEMENTS IN COAL PLATES OR COVERS FOR CELLAR OPENINGS
Year: 1880

page_text: LETTERS PATENT to John Mathewson and George Tidey, both of No. 11,
Denmark Road, Kilburn, in the County of Middlesex, for an Invention of
"IMPROVEMENTS IN COAL PLATES OR COVERS FOR CELLAR OPENINGS."
PROVISIONAL SPECIFICATION left by the said John Mathewson and
George Tidey at the Office of the Commissioners of Patents on the 11th
October 1880.
JOHN MATHEWSON and GEORGE TIDEY, both of No. 11, Denmark Road, Kilburn,
in the County of Middlesex. "IMPROVEMENTS IN COAL PLATES OR COVERS FOR
CELLAR OPENINGS."
Our Invention relates to a construction of coal plates or covers for cellar
openings in such a manner that on their being put in place they become automati-
cally locked, and can only be unlocked from within the cellar. The object of our
Invention being to prevent such covers from being removed by persons outside, and
also to provide against the accidents that often result from the insecure fixing of
such covers. For this purpose we fit to the cover two or more spring arms
projecting downwards, each of these arms having on it a ratchet tooth which,
when the cover is put in place, catches under a shoulder of the fixed frame, the cover
being thus locked." For the purpose of unlocking the cover a person inside the
cellar by grasping the arms that project downwards and closing them together in
opposition to their spring releases the catches from under the shoulder of the frame,
permitting the cover to be lifted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Mathewson and George Tidey, in the Great Seal Patent
Office on the 8th April 1881.
JOHN MATHEWSON and GEORGE TIDEY, both of No. 11, Denmark Road, Kilburn,
in the County of Middlesex. "IMPROVEMENTS IN COAL PLATES OR COVERS FOR
CELLAR OPENINGS."
Our Invention relates to a construction of coal plates or covers for cellar openings
in such a manner that on their being put in place they become automatically
locked, and can only be unlocked from within the cellar. The object of our Invention
being to prevent such covers from being removed by persons outside, and also to
provide against the accidents that often result from the insecure fixing of such
covers. For this purpose we fit to the cover two or more spring arms projecting
downwards, each of these arms having on it a ratchet tooth which, when the
cover is put in place, catches under a shoulder of the fixed frame, the cover being
thus locked. For the purpose of unlocking the cover a person inside the cellar by
grasping the arms that project downwards and closing them together in opposition
to their spring releases the catches from under the shoulder of the frame, permitting
the cover to be lifted.
The accompanying Drawings represent a coal plate or cover for a cellar opening
constructed according to our Invention. Fig. 1 is a side elevation of the coal
plate frame; Fig. 2 is a plan; and Fig. 3 a vertical section of the coal plate or
cover and its frame.
A is the frame which is fixed into the cellar opening in the pavement and has
a ledge on which rests the coal plate or cover B. To the underside of the plate B
are rivetted two spring arms C, C, projecting downwards, each having on it a ratchet
tooth or projection D, which when the cover is put in its place are caused to be
sprung apart by the spring F so as to catch under the shoulders E of the fixed
frame, thus locking the plate in its place. The arms C may be jointed to the plate
B, as shewn in Fig. 4, by pins I passing through lugs K cast on the plate. For the
purpose of unlocking the cover the two projecting arms C, C, are pressed together in
opposition to the spring F by a person inside the cellar, thus releasing the catches D
and allowing the cover to be lifted.
Having thus described the nature of our Invention and in what manner the
same is to be performed, we claim,―
The construction of coal plate or cover for a cellar opening with spring arms,
latching under shoulders of the fixed frame so that when the plate is put in place
it is automatically locked and can only be unlocked from within the cellar,
substantially as herein described.
In witness whereof, I, the said John Mathewson, have hereunto set my hand
and seal, this Seventh day of April, in the year of our Lord One thousand
eight hundred and eighty one.