IMPROVEMENTS IN WIND MOTORS
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
W Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS IN WIND
MOTORS
Communicated to him from abroad by Alexandre Dumont of Paris,
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 1st December 1882.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents,
IMPROVEMENTS IN WIND MOTORS [Communicated to him from abroad by Alexandre
Dumont of Paris, France]
This Invention relates to an improved wind motor having curved vanes or
blades automatically presented to the direction of the wind with or without a
director vane and self governing as regards speed so that the motor can be safely
left unattended and will work equally well in the most violent tempests as in
light winds. It may be constructed of such dimensions as to furnish 10, 15 or
20 horse power if required which has never hitherto been done by wind motors.
In order that the Invention may be more readily understood, I will proceed to
describe it with reference to the accompanying drawings in which Figure 1
represents the outline of the curve of one of the vanes and its projection on a plane
perpendicular to the shaft. Figure 2 represents the projection of the vane on a
vertical plane parallel to the shaft. Figure 3 shows the horizontal projection of
the vane. Figure 4 shows the development of a sector of 79° equal to the surface
occupied by each vane in the geometrical circle formed by the projection of the
entire mill in a plane perpendicular to the shaft. Figure 5 shows the development
with their curvature and inclination in the plane of rotation, of the several trans-
verse lines of the vane, from the centre to the circumference. Figure 6 shows a
perspective view of the front face presented to the wind, of a motor constructed
according to the present Invention, and Figure 7 is a similar view of the rear face
Figures 8 and 9 represent the general arrangement of the motor mounted on a
framework self adjusting to the direction of the wind without a director vane.
Figure 10 shows on a larger scale the principal parts by which this self-adjustment
D
1.
11

page_text: is effected. Figures 11 and 12 represent in elevation and plan a similar mill
adjusted to the direction of the wind by means of a director vane which is also
separately represented on a larger scale in Figure 13 whatever the number of the
vanes they collectively occupy about 7, ths of the geometrical surface of the mill
projected on a plane perpendicular to the shaft. Each vane is curved in its length
from centre to circumference (see Figure 1) inversely to the direction of rotation
according to a demi-parabola whose directrix and focus vary (abcdefghi)
throughout the outline and whose vertex is at the centre Ŏ of the mill. The
curve may be opened or closed more or less, according to requirements, by shifting
the focus nearer to or further from the centre O. Each vane may be divided
transversely into an infinite number of curved lines A B, CD, E F, GH, whose
Each one
projections on a plane perpendicular to the shaft are all concentric.
lies wholly in one plane forming with the plane of rotation of the mill a varying
angle as follows (see Figure 5). The extreme transverse curve A B of the vane
towards the circumference is inclined according to circumstances and the speed to
be attained, so as to form an angle with the plane of rotation, of from 9° to 25°.
From this as a basis the others C. D, E F, nearer the shaft as far as the middle of
the vane, are so inclined that the sine of the angle formed by each with the plane
of rotation shall be inversely proportional to the square of the distance between it
and the centre. The vane at its mid length is thus inclined 35° to 40° to the
plane of rotation and between this point and the shaft, the angle continues to
open proportionally to the distance traversed towards the centre and attains 90° at
said centre. Thus transversely each vane is parallel to the shaft, at the centre
while it forms with it an angle of 45° to 55° midway between the centre and the
circumference of the mill; it also forms with the shaft an angle of from 65° to 81°
at its extremity near the circumference. It will be understood from the foregoing
and also by reference to the perspective views Figures 6 and 7, that all the trans-
verse elements of the rear surface of the vane are inclined to the axis.proportionally
to the square of the velocity, so that the resistance presented by the vane is equal
at all points. By reason of the outline of the curve the same observation applies
to the vane considered in the direction of its length. Hence the vane during its
rotation will be uniformly sustained at all points by the resistance of the air and
this enables the mill to be constructed lightly and of very large dimensions and to
be exposed to the most violent tempests without reducing its surface
On the other hand the angle formed by the vane with the plane of rotation
being 90° near the shaft and from 35° to 45° at about mid length of the
vane it follows that the surface nearest to the centre of the mill will be in some
degree sacrificed as regards useful work the loss of which is not however very
prejudicial as the work done near the centre is inconsiderable. But this part
which forms a very open angle with the plane of rotation acts as a sort of regulator
the effect being slight with light winds when the motion is slow, but which
becomes on the contrary very powerful when the motion is accelerated. The root
of the vane being parallel to the shaft at the point where it is attached thereto
great strength is ensured.
I will now proceed to describe a practical construction of the framing of the
improved wind motor with reference to figures 8, 9 and 10. The motor constructed
as described is poised upon a pivot H at the top of a hollow vertical column M so
as to be freely turned to the direction of the wind by the pressure against the
vanes themselves or by means of a directing vane. This pivot has a central
aperture for the passage of the vertical shaft K which is geared by mitre wheels
P, Q, with the mill shaft L and passes down through the hollow column. A is a
box weighted with stones, sand or other materials to counterpoise the vanes and
their accessories and thus balance the mill upon the pivot H. At CD are two sets
of friction rollers (each six in number) mounted upon the framing Y and running
around the column M so as to maintain the frame in position. B, B, are two
rollers beneath the framing and close to but not touching the ground when the
wind is light and the framing is in equilibrium, but which bear and run upon a

page_text: racer plate X and support the framing when the mill yields slightly under the
pressure of a strong wind. As shown in Figure 8 the horizontal shaft E F, has a
conical steel point which while the mill is in work bears against a plate G to
take the end thrust of the shaft. Figure 10 is a section showing details on a
larger scale, The pivot H rests in a cup or concave bearing I at top of the
columnn M. The vertical shaft K passes freely through the pivot H but turns as
in a bearing in the cup which has a leather packing at J to prevent the escape of
the oil contained in cup I. Instead of mitre wheels PQ a disc may be fixed on
the end of the shaft so as to obtain a direct transmission of motion in small mills.
The advantages of this improved motor are 1st an exceedingly sensitive adjustment
so as to utilise the very lightest breezes 2nd great strength to resist high winds
combined with lightness of construction. 3rd The end thrust of the mill shaft being
entirely taken by plate G the shaft rotates on its point F with little friction From
experiments extending over a period of several months, it has been found that
there is no wear of the point of the shaft on its end bearing this pressure being
almost nil, by reason of the form of the vanes which as before mentioned are
firmly sustained by the resistance of the air upon their rear face.
As above described, the adjustment of the mill is automatic without the aid of a
directing vane and Figures 11, 12 and 13 show a similar mill in which a direct
vane is employed to adjust the mill, and also to regulate its speed. This is shown
in Figures 11 and 12 and consists of two directing vanes or rudders mounted
vertically at the rear of the mill. One of them A. C is inclined at about 35° to
the plane of rotation of the vanes and is a fixture to the framing while the other
A. B when in repose makes an equal angle in the opposite direction but is free to
move in an arc of a circle about point A as a centre and thus to approach close up
to rudder A. C. As shown in Figure 13 the rudder A. B turns upon screw or rising
pivots so that in approaching AC it will also be raised and will therefore always
tend with more or less force to return to its lowest position according to the pitch
of the rising pivots. It should be observed that when the mill is left to itself
without a means of adjustment the plane of rotation of the vanes will not be
perpendicular to the direction of the wind but inclined thereto at a greater or less
angle, this being due to the peculiar conformation of the vanes and the two
rudders A B, A C, are therefore made of such different areas as will exactly
counteract this tendency. The angle of 35° to which they are set being also
varied, with the same object.
The arrows D V in Figure 12 show the direction of the wind and the full lines
represent the position of the mill with regard to this direction in a breeze of
which it is desired to utilize the whole force. In this position the entire surface of
the vanes is so presented to the wind as to produce a useful effect. When the wind
freshens beyond that demanded by the work to be performed it will be of sufficient
strength to cause the rudder A B to turn on its pivots A, whereupon the equilibrium
between the two rudders being destroyed, the mill will slightly shift its position
and present less surface to the wind. The rudder A B tbus momentarily shifted
returns automatically to its normal position as well as the framing, if the gust of
wind be but momentary or becomes still further shifted if the gale continues.
During a storm the mill might thus assume the position represented in dotted lines
at an angle of about 45° to the direction of the wind. In this position good work
is done although one third only of the area of the vanes is exposed to the wind
which strikes full against the descending vanes only the ascending ones being
presented edgewise. By this apparatus which is not however indispensable, the
working of the motor may be regulated when the wind is blowing a stiff breeze
and the framing relieved during hurricanes. The directing vanes or rudders may
also be constructed and mounted in any other suitable manner and may also be
applied to all other kinds of wind mills for the purpose of diminishing the area
presented to a high wind.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on the
30th May 1883.
ALEXANDER MELVILLE CLARK of the Firm of A, M, and W, Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents
"IMPROVEMENTS IN WIND MOTORS A communication to me from abroad by
Alexandre Dumont of Paris Franco
"
This Invention relates to an improved wind motor having curved vanes or blades
which are automatically presented to the direction of the wind with or without
the aid of a director vane, the motor being self governing as regards speed so that
it can be safely left unattended and will work equally well in the most violent
tempests and in light winds. It may be constructed of such dimensions as to
furnish 10, 15 or 20 horse power if required which has never hitherto been done by
wind motors.
In order that the Invention may be more readily understood, I will proceed to
describe it with reference to the accompanying drawings in which Figure 1
represents the outline of the curve of one of the vanes and its projection on a plane
perpendicular to the shaft. Figure 2 represents the projection of the vane on a
vertical plane parallel to the shaft. Figure 3 shows the horizontal projection of
the vane. Figure 4 shews the development of a sector of 79° equal to the surface
occupied by each vane in the geometrical circle formed by the projection of the
entire mill on a plane perpendicular to the shaft. Figure 5 shows the development
with their curvature and inclination to the plane of rotation, of the several trans-
verse lines of the vane, from the centre to the circumference. Figure 6 represents
the outline of the curve of a vane in which the angle of obliquity of the transverse
curves is regulated according to the cotangent of their arc, and the projection of the
vane on a plane perpendicular to the shaft. Figure 7 represents the projection of
the same vane on a plane parallel to the shaft. Figure 8 shews a perspective view
of the front face presented to the wind, of a motor constructed according to the
present Invention, and Figure 9 is a similar view of the rear face. Figures 10
and 11 represent the general arrangement of the motor mounted on a framework
self adjusting to the direction of the wind without a director vane. Figure 12
shows on a larger scale the principal parts by which this self adjustment is effected.
Figures 13 and 14 represent in elevation and plan a similar mill adjusted to the
direction of the wind by means of a director vane which is also separately
represented on a larger scale in Figure 15.
Whatever the number of the vanes they collectively occupy about 7th of the
geometrical surface of the mill projected on a plane perpendicular to the shaft.
Each vane is curved in its length from centre to circumference (see Figure 1)
inversely to the direction of rotation according to a demi-parabola whose directrix
and focus vary (a b c d e f g h i) throughout the outline the vertex of the parabola
being at the centre O of the mill. The curve may be opened or closed more or less,
according to requirements, by shifting the focus nearer to or further from the
centre O. Each vane may be divided transversely into an infinite number of curved
lines AB, CD, EF, GH, (figures 1 to 8) whose projections on a plane perpen-
dicular to the shaft are all concentric. Each one lies wholly in one plane forming
with the plane of rotation of the mill a varying angle as follows (see figure 5).
The extreme transverse curve A B of the vaue towards the circumference is inclined
according to circumstances and the speed to be attained, so as to form an angle with
the plane of rotation, of from 9° to 25°. From this as a basis the others CD, E, F
nearer the shaft as far as the middle of the vane, are so inclined that the sine of the

page_text: angle formed by each with the plane of rotation shall be inversely proportional to
the square of the distance between it and the centre. The vane at its mid length
is therefore inclined 35° to 40° to the plane of rotation and between this point
and the shaft, the angle continues to open proportionally to the distance traversed
towards the centre and attains 90° at said centre. Thus transversely each vane is
parallel to the shaft at the centre while midway between the centre and the
circumference of the mill; it forms with the shaft an angle of 45° to 55°, and at its
extremity near the circumference it forms with it an angle of from 65° to 81°.
Instead of regulating the angle of obliquity of the transverse curves
A B, CD, EF, GH, &o. constituting the vane, in the manner before described, that
is to say, so that the sine of the angle formed by each with the plane of rotation
shall be inversely proportional to the square of the distance between each and the
centre, I may also while retaining the same principle of proportionality regulate
the angle of the transverse curves according to the cotangent of their arc, That of
the curve A B which is the furthest from the shaft I make of from 28° to 35° the
others being reduced in proportion to the distance between each and the centre.
Figures 6 and 7 are vertical projections of the vane thus constructed on planes of
which one is perpendicular and the other parallel to the shaft of the mill.
On the other hand I increase in suitable proportion the curve OH F D B to
which the vane is bent in the direction of its length, in order that by combining
the inclination of said curve with the obliquity of the vane each part of the
posterior face of the vane shall always recede inversely to the direction of motion,
proportionally to the square of the velocity of this part in rotating.
It will be understood from the foregoing and also by reference to the perspective
views Figures 8 and 9, that all the transverse elements of the rear surface of the vane
are inclined to the axis proportionally to the square of the velocity, so that the
resistance encountered by the vane is equal at all points. By reason of the outline
of the curve above explained the same observation applies to the vane considered in
the direction of its length. Hence the vane during its rotation will be uniformly
sustained at all points by the resistance of the air and this enables the mill to be
constructed lightly and of very large dimensions and to be exposed to the most
violent tempests without reducing its surface.
On the other hand the angle formed by the vane with the plane of rotation
being 90° near the shaft and from 35° to 45° at about mid length of the vane it
follows that the surface nearest to the centre of the mill will be in some degree
sacrificed as regards useful work the loss of which is not however very prejudicial
as the work done near the centre is inconsiderable. But this part which forms &
very open angle with the plane of rotation acts as a sort of regulator, the effect
being slight with light winds when the motion is slow, but which becomes on the
contrary very powerful when the motion is accelerated. The root of the vane
being parallel to the shaft at the point where it is attached thereto great strength
is ensured.
I will now proceed to describe a practical construction of the framing of the
improved wind motor with reference to figures 10, 11 and 12. The motor
constructed as described is poised upon a pivot H at the top of a hollow vertical
column M so as to be freely turned to the direction of the wind by the pressure
against the vanes themselves or by means of a directing vane. This pivot has
a central aperture for the passage of the vertical shaft K which is geared by
mitre wheels PQ, with the mill shaft L and passes down through the hollow
column. A is a box weighted with stones, sand or other materials to counterpoise
the vanes and their accessories and thus balance the mill upon the pivot H.
At CD are two sets of friction rollers (each six in number) mounted upon the
framing Y and running around the column M so as to maintain the frame in
position. B, B, are two rollers beneath the framing and close to but not touching
the ground when the wind is light and the framing is in equilibrium, but which
bear and run upon a racer plate X and support the framing when the mill yields
slightly under the pressure of a strong wind. As shown in Figure 10 the

page_text: horizontal shaft E, F, has a conical steel point F which while the mill is in work
bears against a plate G to take the end thrust of the shaft. Figure 12 is a section
showing details on a larger scale. The pivot H rests in a cup or concave bearing I
at top of the column M. The vertical shaft K passes freely through the
pivot H but turns as in a bearing in the cup which has a leather packing at J to
prevent the escape of the oil contained in cup I. Instead of mitre wheels P Q a
disc may be fixed on the end of the shaft so as to obtain a direct transmission of
motion in small mills. The advantages of this improved motor are 1st an
exceedingly sensitive adjustment so as to utilise the very lightest breezes.
2nd great
strength to resist high winds combined with lightness of construction. 3rd The end
thrust of the mill shaft being entirely taken by plate G the shaft rotates on
its point F with little friction. From experiments extending over a period of
several months, it has been found that there is no wear of the point of the shaft on
its end bearing, this pressure being almost nil, by reason of the form of the vanes
which as before mentioned are firmly sustained by the resistance of the air upon
their rear face.
As above described, the adjustment of the mill is automatic without the aid of a
directing vane and Figures .13, 14 and 15 show a similar mill in which a director
vane is employed to adjust the mill, and also to regulate its speed. This is shown
in Figures 13 and 14 and consists of two vanes or rudders mounted vertically at
the rear of the mill. One of them A C is inclined at about 35° to the plane of
rotation of the mill vanes and is a fixture to the framing while the other A B when
in repose makes an equal angle in the opposite direction but is free to move in an
arc of a circle about point A as a centre and thus to approach close up to
rudder A C. As shown in Figure 15 the rudder A B turns upon a screw or rising
pivots so that in approaching A C it will also be raised and will therefore always
tend with more or less force to return to its lowest position according to the pitch
of the rising pivots. It should be observed that when the mill is left to itself
without a means of adjustment the plane of rotation of the vanes will not be per-.
pendicular to the direction of the wind but inclined thereto at a greater or less
angle, this being due to the peculiar conformation of the vanes and the two
rudders A. B, A C, are therefore made of such different areas as will exactly.
counteract this tendency, the angle of 35° to which they are set being also varied,
with the same object.
The arrows D V in Figure 14 show the direction of the wind and the full lines
represent the position of the mill with regard to this direction in a breeze of which
it is desired to utilize the whole force. In this position the entire surface of the
vanes is so presented to the wind as to produce a useful effect. When the wind
freshens beyond that demanded by the work to be performed it will be of sufficient
strength to cause the rudder A B to turn on its pivots A, whereupon the equilibrium
between the two rudders being destroyed, the mill will slightly shift its position
and present less surface to the wind. The rudder A B thus momentarily shifted
returns automatically to its normal position as well as the framing, if the gust of wind
be but momentary or becomes still further shifted if the gale continues. During a
storm the mill might thus assume the position represented in dotted lines at an
angle of about 45° to the direction of the wind. In this position good work is
done although one third only of the area of the vanes is exposed to the wind
which strikes full against the descending vanes only, the ascending ones being
presented edgewise. By this directing apparatus which is not however indis-
pensable, the working of the motor may be regulated or modified when the wind
is blowing a stiff breeze and the framing relieved during hurricanes. The directing
vanes or rudders may also be constructed and mounted in any other suitable
manner and may also be applied to all other kinds of wind mills for the purpose of
diminishing the area presented to a high wind.
The form dimensions and arrangement of the various parts of this improved
wind motor and its accessories may be varied as well as the materials of which it
is constructed without in any way departing from the invention.

page_text: Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is :-
First. A wind motor having vanes constructed arranged and operating
substantially as herein described and represented in Figures 1 to 9.
Second. The construction and arrangement of counterpoised pivotted frame for
enabling the nill to adjust itself to the wind without the aid of a directing vane,
substantially as described and shown in figures 10, 11 and 12.
Third. The directing vane or rudder constructed arranged and operating sub-
stantially as described and illustrated in figures 13, 14 and 15, whereby the
position and speed of the mill are adjusted and regulated, whether the construction
of the mill be such as above described or otherwise constructed.
In witness whereof I the said Alexander Melville Clark have hereunto set
my hand and seal this twenty-ninth day of May in the year of our Lord
One thousand eight hundred and eighty three.
4
DU
A. M. CLARK (LAS.)