Improvements in Ventilating Fans.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Ventilating Fans.
We, WILLIAM MATTHEWS and JOSEPH YATES, both of 35 Lever Street Manchester
in the County of Lancaster, Ventilating Engineers, 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:-
This Invention relates to the construction and arrangement of the blades or vanes
and of the bosses of ventilating fans and these Improvements consist in constructing
the blades with a straight leading edge, a curved following edge, and a longitudinal
curvature, and in securing the blades to the boss at an angle; they also consist in
forming flanges at the inner ends of the blades and flats upon the boss, and in
connecting the blades to the boss by means of set screws passing through holes in the
flanges into tapped holes in the flats on the boss.
And in order that our Invention may be more readily understood and carried into
practical effect we have appended hereto a sheet of drawings in which Fig. 1 is a plan
of the fan viewed from the delivery side; Fig. is a side view; Fig. 3 is a cross
section of one of the blades, and Fig. 4 is a plan of one of the blades after it has
been cut out and before it has been bent.
Each blade of a fan constructed according to these Improvements is cut from sheet
metal (preferably iron or mild steel) with a straight leading edge and with a curved
following edge approximately as shewn in Fig. 4. The total length of the blank is
from one inch to one and a half inches greater than the desired finished length of the
blade and this excess of length at the inner end of the blade is turned at a right
angle along the dotted line A Y Fig. 4, so as to form a flange by means of which
the blade may be secured to the boss of the fan, and for this purpose two or more
holes are formed therein. A longitudinal curvature is given to the blades so that
the cross section of each blade along the line A X Fig. 4 is as represented in Fig. 3.
The curvature of the blades is also indicated by the end view Fig. 2, and the plan
Fig. 1. Diagonal flats B are formed at equal intervals upon the boss C so as to
form plane seatings for the flanges upon the inner ends of the blades, and these
The blades
are drilled and. tapped to correspond with the holes in the flanges.
are then secured to the boss by means of set screws passing through the holes in
the blade flanges into the tapped holes in the flats. The blades are so mounted
upon the boss that the longitudinal curvature is concave on the leading side as shewn
in the Figure 1 and 2 where the direction of rotation is indicated by arrows.
The fan constructed as hereinbefore described is mounted upon a spindle within a
ring, tube, framing or casing in the usual manner and as well understood and commonly
practised in the construction of ordinary ventilating fans.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
(1) A ventilating fan having its blades and boss constructed and arranged substan-
tially as hereinbefore described with reference to the accompanying drawings.
(2) In a ventilating fan; the hereinbefore described means for and method of
securing the blades to the boss, consisting of flanges formed at right angles to the
blades, flats formed upon the boss, the blades and the boss being secured together by
means of set screws passing through the flanges into the flats, substantially as set
forth.
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