IMPROVEMENTS IN APPARATUS FOR WORKING PUNKANS
Year: 1876

page_text: LETTERS PATENT to George Henry Marshall, of Weedon, in the County of
Northampton, Captain, Royal Artillery, for the Invention of "IMPROVEMENTS
IN APPARATUS FOR WORKING PUNKANS."
Sealed the 1st September 1876, and dated the 31st March 1876.
PROVISIONAL SPECIFICATION left by the said George Henry Marshall at the
Office of the Commissioners of Patents on the 31st March 1876.
GEORGE HENRY MARSHALL, of Weedon, in the County of Northampton, Captain,
Royal Artillery. IMPROVEMENTS IN APPARATUS FOR WORKING PUNKAHS."
"
My apparatus for working punkahs can be easily adapted to the method of
suspending and pulling punkahs in general use at present in barracks, hospitals,
and large public buildings in India, which method may be thus briefly
described:
Each punkal consists of an oblong light wooden frame stretched with canvas and
suspended by cords to two hooks in the ceiling; a deep fringe of cloth material is
attached to the lower edge of the frame. In a barrack room there are usually two
rows of beds, and a row of punkals is suspended over cach row of beds. The
frames of several of the punkahs are connected together by horizontal rods or
cords; each batch or set so joined together is pulled by one man by means of a
rope attached to the centre of the end frame. By this method a sufficiently free
swing cannot be obtained, for if only a few heavy punkahs are joined together and
allowed to swing at all freely the are described by cach becomes large and the
punkans get beyond the control of the man pulling them, the result in practice
is that the man checks the swing, thus causing insufficient agitation of the air.
My apparatus consists of a horizontal cross rod r (Figure 1) fixed to the vertical
suspending ropes b, b, of each punkah at a certain distance from the points of
suspension; this distance may vary according to the lengths of the cords and swing
required. From the centre of each cross rod r, and at right angles to it, a longi-
tudinal rod connects it to the next cross rod; this series of longitudinal connecting
rods we may consider and call one longitudinal rod l.
By imparting motion to the rod the whole set of punkahs in connection with
it will be put in motion.
On reference to Figure 2 (a longitudinal section of barrack room) it will be seen
Dasis G71

page_text: that to cause cach punkah A to swing through the arc x, x, x, the longitudinal
rod need only be moved through the arc y, y, y. Thus, say the length of the
cord b is 18 feet, and the rod fixed 6 feet below the point of suspension, in order
to give the punkah A a swing of 12 feet it will be necessary to give a motion
of 4 feet only. By thus reducing or limiting the space in which the motive power
has to act I bring the system of punkahs under the control of machinery or of the
simplest mechanical contrivances, which will vary to suit the size of the building
and number of punkahs, or so that one inan working at the end of the barrack can
give motion to any number of punkahs which may be required.
I give rectilinear motion to the rod Z by means of a crank or eccentric. Where
two sets of punkahs are worked in one room the longitudinal rods can be con-
nected at the ends by a cross rod, and both sets worked by one crank; or two
eccentrics set opposite to each other might be used, thus causing the two sets of
punkahs to swing in opposite directions.
No complicated machinery being necessary the apparatus may be applied to
existing arrangements by ordinary artificers and at a trifling cost.
Briefly, my Invention consists in the employment of connecting rods on the
suspending ropes or cords, working the punkahs therefrom, thus giving a small
space for the motive power to act in, thereby bringing the system under the
control of simplest machinery or mechanical contrivances.
The resulting advantages are,-
Saving of manuel labour.
Increased swing and efficiency of punkah, while the apparatus, owing to its
simplicity, can be adapted to existing systems at a small cost.
The apparatus can also be applied to work at one time the punkahs in the
different rooms of a private house.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Henry Marshall in the Great Seal Patent Office on the 29th
September 1876.
GEORGE HENRY MARSHALL, of Weedon, in the County of Northampton, Captain,
Royal Artillery. "IMPROVEMENTS IN APPARATUS FOR WORKING PUNKAHS."
My apparatus for working punkahs can be easily adapted to the method of
suspending and pulling punkals in general use at present in barracks, hospitals, and
large public buildings in India, which method may be thus briefly described :-
Each punkah consists of an oblong light wooden frame stretched with canvas,
and suspended by cords to two hooks in the ceiling. A deep fringe of cloth material
is attached to the lower edge of the frame. In a barrack room there are usually
two rows of beds, and a row of punkahs is suspended over each row of beds. The
frames of several of the punkahs are connected together by horizontal rods or cords;
cach batch or set so joined together is pulled by one man by means of a rope
attached to the centre of the end frame. By this method a sufficiently free swing
cannot be obtained, for if only a few heavy punkahs are joined together and allowed
to swing at all freely, the arc described by cach becomes large, and the punkahıs get
beyond the control of the man pulling them. The result in practice is that the man
checks the swing, thus causing insufficient agitation of the air.
My apparatus consists of a horizontal cross rod r (Figure 1) fixed to the vertical
suspending ropes b, b, of each punkah at a certain distance from the points of
suspension; this distance may vary according to the lengths of the cords and swing
required. From the centre of each cross rod r, and at right angles to it, a longi-
tudinal rod connects it to the next cross rod; this series of longitudinal connecting
rods we may consider and call one longitudinal rod l.
By imparting motion to the rod the whole set of punkahs in connection with it
will be put in motion.

page_text: On reference to Figure II. (a longitudinal section of barrack room) it will be seen
that to cause each punkah A to swing through the are x, x, x, the longitudinal rod
need only be moved through the arc 3, 3, 3. Thus, say the length of the cord b is
18 feet, and the rod fixed 6 feet below the point of suspension, in order to give the
punkah A a swing of 12 feet it will be necessary to give a motion of 4 feet only.
By thus reducing or limiting the space in which the motive power has to act I
bring the system of punkahs under the control of machinery, or of the simplest
mechanical contrivances, which will vary to suit the size of the building and number
of punkahs, or so that one man working at the end of the barrack can give motion
to any number of punkahs which may be required.
In Figures I. and III. is seen a simple plan of working a double row of punkahs.
A connecting rod e is hinged to the centre of each end cross rod ; the other ends
of these connecting rods are bolted to the circular plates f; these plates serve
as cranks, a slot in each plate enabling the bolt of the connecting rod to be shifted
so as to allow of adjustment to whatever stroke may be required; these crank slots
are set at right angles to each other, to cause the two sets of punkahs to swing in
opposite directions; the plates f, f, are turned by a spindle g in connection with
the vertical spindle h, worked by two sets of bevelled cog wheels, a fly wheel, and
crank handle, the whole being bracketted to the wall at the end of the room.
Briefly, my Invention consists in the employment of connecting rods on the
suspending ropes or cords, working the punkalis therefrom, thus giving a small. spaco
for the motive power to act in, thereby bringing the system under the control of
simplest machinery or mechanical contrivances.
The resulting advantages are,-
Saving of manual labour.
Increased swing and, efficiency. of punkah, while the apparatus, owing to its sim-
G. H. MARSHALL. (L.S.)