Improvements in Apparatus for Working Punkahs.
Year: 1889

page_text: Date of Application, 23rd Nov., 1889
Complete Specification Left, 25th Aug, 1890-Accepted, 22nd Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Working Punkahs.
I, HENRY EDMOND WALTER of 31 Westbourne Terrace London W. Electrician do
hereby declare the nature of this invention to be as follows:-
For actuating punkahs I employ an arm or pendulum kept swinging to and fro by
the action of an electro magnet in the following manner.
The electro magnet is carried by the pendulum and its pole or poles are brought
intoclose proximity to an arc of ratchet like teeth which is held from moving-or the
arc might be on the pendulum and the magnet fixed.
Preferably I use a magnet of horse shoe form with the two magnet poles at a distance
apart equal to the distance between the ratchet like teeth.
As the pendulum swings to and fro when the magnet poles are carried beyond
the summits of two of the teeth an electric current is caused to pass through the
magnet coils and the magnet is so energized-the magnet poles are then attracted to
the summit of the next teeth-the current is then broken and when the poles have
passed these teeth the current is again completed and so on.
When the pendulum has arrived at the end of its swing and begins to swing back
in the opposite direction the current is automatically cut off altogether from the
magnet.
For one half of the swing the ratchet teeth might be in one direction and for the
other half in the opposite direction. In this way the pendulum might be driven for
one half the swing in each direction.
For controlling the passage of a current to the magnet coils a spring or brush
carried by the pendulum may be made to work over an arc of fixed contact plates.
In order to ensure that the magnet poles shall always be at the same distance
from the summits of the teeth the arc of teeth may be carried by suspension rods
from the axis of the pendulum and be held to a wall to restrain it from swinging to
and fro.
The punkah may be on the same axis as the pendulum of the motor or it may be
on an axis parallel with it and be coupled to the pendulum by a connecting rod.
The pendulum motor may be in a separate room from that in which the punkah
works and the axis or connecting rod be carried through the division wall or the
motor may be enclosed in a casing at one side or end of the room.
Dated this 23rd day of November 1889.
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Working Punkahs.
I, HENRY EDMOND WALTER of 31 Westbourne Terrace London W. Electrician,
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:
For actuating punkahs I employ an arm or pendulum kept swinging to and fro
by the action of an electro magnet in the following manner :-
The electro magnet is carried by the pendulum and its pole or poles are brought
into close proximity to an arc of ratchet like teeth which is held from moving-or the
are might be on the pendulum and the magnet fixed.
Preferably I use a magnet of horse shoe form with the two magnet poles at a
distance apart equal to the distance between the ratchet like teeth.

page_text: Sam completed and so on.
For controlling the passage of the current to the magnet coils a spring or
brush carried by the pendulum may be made to work over an arc of fixed contact
plates.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front elevation of a punkah and electro-magnetic apparatus by which
.it is actuated.
Figure 2 is an end view of the same.
Figure 3 shews to a larger scale the contact maker and circuit arrangements.
a is the pendulum rod, it is fixed to the axis b. The punkah c is also carried by
the axis b. d is an iron are provided with flattened teeth or undulations d¹ d', this
arc is fixed to a frame which may also aid in supporting the axis b. e is an
electro-magnet which forms the bob of the pendulum, it is fixed upon the rod a or
it may be adjustable thereon so that as the pendulum swings the magnet poles just
clear the teeth d¹.
The electro-magnet is included in circuit with a galvanic battery or other source
of current and with a contact maker which opens and closes the circuit during the
swing of the pendulum.
The circuit is closed whilst the magnet poles are approaching the summits of the
teeth opposite to which they are, and it is open whilst the poles recede from the
summits of the teeth. This may be effected in the manner shewn in Figure 3. ƒ is
a metallic are suitably fixed and insulated from the other parts of the apparatus
excepting the wire g which connects it with one pole of a battery and the metallic
circuit closing brush i which makes contact with it intermittently during the swing
of the pendulum. The brush i is carried by a piece k which is moveable around the
axis but with a little friction (applied by a spring not shewn in the drawing) so
that the piece k remains at rest except when propelled by the pendulum rod a bearing
against one or other of the adjustable stops 1 1². m m are a pair of wires led up
the pendulum rod a from the electro-magnet e to its upper end; thence one of the
wires is conducted to the other pole of the battery h or to the pole which is not
already connected with the wire g. The other wire m is connected with the metallic
contact brush i.
The action is as follows:-As represented in Figure 3 the pendulum is supposed
to be swinging from right to left and the rod a is bearing against the stop and by
driving the piece k is just bringing the brush into metallic contact with the arcf;
the magnet e is consequently commencing to be energised. Figure 2 shews the
position of the magnet relatively to the teeth d¹; as the pendulum swings towards
the left the attraction of the magnet for the adjacent teeth imparts an impulse. As
soon as the magnet poles are above the summits of the teeth the brush i ceases to be
in contact with the arc fand the magnet becomes passive. As the next tooth d¹ is
approached by the magnet pole the action is repeated and so on until the pendulum
comes to the end of its swing. Gravity immediately causes the pendulum to return
and as it does so it receives afresh a series of impulses. The contact brush i is now
driven by the pendulum rod a bearing against the stop 12 and the contacts con-
sequently are differently timed so that now the magnet is energised when its poles
are on the left side of the summits of the teeth which they are approaching whereas
previously the attraction took place when the poles were to the right of the summits.
In this way the swing of the pendulum is constantly maintained notwithstanding the
resistance of the punkah.

page_text: In order to ensure that the magnet poles shall always be at the same distance from
the summits of the teeth the arc of teeth may be carried by suspension rods
from the axis of the pendulum and be held to a wall to restrain it from swinging
to and fro.
The punkah may be on the same axis as the pendulum of the motor or it may
be on an axis parallel with it and be coupled to the pendulum by a connecting rod.
The pendulum motor may be in a separate room from that in which the punkah
works and the axis or connecting rod be carried through the division wall or the
motor may be enclosed in a casing at one side or end of the room.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Apparatus for working punkahs and consisting of a pendulum, the swing of
which is maintained by an electro-magnet intermittently attracting an arc sub-
stantially as described.
2. Apparatus substantially as described and illustrated by the annexed drawings.
Doted thin 95th dose of August 1890
CARPMAEL & Co.,
Agents for the Applicant.