Year: 1887

page_text: Date of Application, 12th July, 1887
Complete Left, 9th May, 1888
Complete Accepted, 15th June, 1888
I, ALFRED HAMILTON DOUGLAS-HAMILTON of 8 Chilworth Street, Westbourne
Terrace in the County of Middlesex, Gentleman do hereby declare the nature of this
invention to be as follows:-
:―
My invention relates to the construction of a cowl or windguard for a chimney or
ventilating shaft in such a manner that when the wind blows on the one side or the
other, the access of wind to the chimney is almost stopped on the windward side while
free opening is given from the chimney or shaft on the lee-ward side. For this purpose,
between two vertical sides extending up from the chimney or shaft I fix on a horizontal
axis two flaps forming with each other an obtuse angle at or near the axis on which
they are fixed, the edges of the flaps being presented downwards, and the flaps being
of such length that as they rock on their axis the edge of the one of them reaches a
flat base at the top of the chimney or shaft while the edge of the other is raised above
this base sufficiently to give free outlet laterally from the chimney or shaft. In order
to render the flaps sensitive in all positions to very small wind force, I mount on them
above the axis a heavy arm having such weight and leverage that the centre of gravity
of the moving parts is very nearly coincident with, but a little below, the axis of
motion.
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
An Improvement in Cowls or Wind Guards.
I, ALFRED HAMILTON DOUGLAS-HAMILTON, of 8 Chilworth Street, Westbourne
Terrace, in the County of Middlesex, Gentleman, 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 the construction of a cowl or windguard for a chimney or
ventilating shaft in such a manner that when the wind blows on the one side or the
other, the access of wind to the chimney is almost stopped on the windward side,
while free opening is given from the chimney or shaft on the leeward side.
For this purpose, I construct the cowl or windguard as I will describe referring to
the accompanying drawing which is a vertical section.
Between two vertical sides A extending up from the chimney or shaft B, I fix on
a horizontal axis C two flaps D D¹ forming with each other an obtuse angle at or near
the axis C, and of such length that as they rock together on their axis C, one of them
such as D reaches a flat base E at the top of the chimney or shaft B while the edge of
the other flap D¹ is raised above the base E sufficiently to give free outlet laterally
from the chimney or shaft as indicated by the arrows. In order to render the flaps D D¹
sensitive in all positions to small wind force, I fix on them above the axis C a loaded
arm F having such weight and leverage that the centre of gravity of the moving parts
is very nearly coincident with but a little below the axis of motion C.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The construction and use of a cowl or windguard substantially as herein described
and illustrated by the accompanying drawing.
ABEL & IMRAY,
Agents for the Applicant.