Improvements relating to Punkahs and to Machinery for Operating the same.
Year: 1891

page_text: Date of Application, 1st June, 1891
Complete Specification Left, 1st Apr., 1892--Accepted, 28th May, 1892
PROVISIONAL SPECIFICATION.
Improvements relating to Punkahs and to Machinery for Operating
the same.
SIDNEY MANTHORP COCKBURN 66 Victoria Street Westminster Engineer, do
hereby declare the nature of this invention to be as follows:-
My invention relates to punkahs and to machinery for operating the same, and
is chiefly designed to simplify the construction and increase the efficiency of such
machinery.
In the machinery heretofore devised for this purpose, much difficulty has been
experienced, in effecting the movement of the punkah in a manner similar to that
produced when the punkah is operated by manual power.
To overcome this difficulty or defect, 1 provide for the operation of the punkah
by mechanism which will alternately impart the necessary movement to the punkah
and permit the return movement thereof under the action of gravity, and which
will perform its work efficiently notwithstanding variations in the length or rapidity
of the swing movement or oscillation of the punkah.
I provide for the operation of the controlling valve by the punkah itself, so that,
whatever may be the length or the rapidity of the swinging movement of the
punkah, the said valve will be opened when, or immediately after the punkah has
terminated its return movement.
I also provide for the operation of a variable cut off, so that the pressure can be
allowed to act during a greater or less portion of the stroke or swing of the
punkah.
Another feature of my said invention is the combination, with the punkah, of a
cylinder and piston and suitable mechanism for connecting the said piston with the
punkah, all the parts being so well arrange that a single stroke or movement of
the said piston will effect the movement of the punkah from one to the other end
of its stroke or swing.
My said invention also comprises other improvements hereinafter mentioned.
I find it advantageous to employ a cylinder provided with a piston and with
suitable means whereby steam at a low pressure may be admitted to the space in
the said cylinder on one side of the piston and whereby the space in the said
cylinder on the other side of the piston, may be put in communication with the
external atmosphere or may be closed as required. This cylinder is preferably
made of such length that a single stroke or movement of the piston therein will
effect the movement of the punkah throughout its entire stroke or swing, the
operation resembling very closely that of a man working the punkali by pulling
upon a rope or cord. The said piston is connected by a toothed rack to a toothed
wheel mounted upon a shaft, on which is also mounted the wheel around which the
punkah cord is wound.
Instead of suspending the punkah by hinges or other devices which are liable to
produce noise if not properly lubricated, I sometimes suspend the punkah by means
of springs like those used in some clocks for supporting the pendulum.
The controlling and variable cut off valve is arranged to be operated by suitable
devices in the rotation of the said shaft alternately in either direction.
For
example, the controlling valve is connected with an arm attached to a clip or clamp
which is mounted upon the shaft and is held thereon tightly enough to ensure its
rotation therewith during a portion of the stroke or swing of the punkah, for the
purpose of operating the controlling valve, whilst permitting rotation of the shaft
independently of the said clip or clamp during the continued movement of the
punkah. Suitable stops are provided for limiting the movement of the arm and

page_text: valve, and the ends of the said arm or the said stops are provided with cushions to
prevent noise.
The cut off is arranged to be operated by a moveable quadrant, mounted on a
wheel which receives proper movement from the main shaft by means of toothed
wheels, and which acts on the arm or clip before mentioned in such a manner as to
cause the admission side of the valve to close at any required point of the stroke of
the piston according to the position given to the quadrant.
I provide for cushioning the piston as the punkah approaches the end of its
return stroke or swing and for obtaining an initial pull upon the punkalı as soon
as its return movement ceases. For this purpose I employ on the quadrant wheel
a moveable pin which acts on the arm or clip in the reverse direction of the action
of the quadrant and which occupies such a position that it will cause the exhaust
side of the valve to close just before the end of the stroke of the piston. The
cushion may be increased or diminished by the position given to the moveable pin.
I mount the apparatus above described upon a suitable base provided with
adjustable feet whereby it can be conveniently levelled when placed upon an uneven
floor, or the engine may be mounted on the top of the steam generator to be herein-
after described.
I also mount upon the said base or in any other convenient manner a suitable
steam generator, which is connected by a flexible or other pipe with the controlling
valve, and is provided with a suitable safety valve which may also actuate a door
or damper to turn the products of combustion into the atmosphere without passing
under the generator should the pressure in the generator rise above a certain point.
In the case of the generator being heated by gas the safety valve would control
the admission of gas.
The capacity of the generator may be such as to hold sufficient water to last for
9 or 10 hrs. or a feed pump may be provided and worked from the engine.
The generator is heated by an oil or other lamp placed in a casing beneath it or
by means of a small gas producer suitably arranged in the said casing or by other
convenient means. The said casing may extend around and over the generator and
is provided with a suitable flue or outlet furnished with a damper.
Compressed air or other fluid may be used in the engine instead of steam.
DLA
S. M. COCKBURN.
COMPLETE SPECIFICATION.
Improvements relating to Punkahs and to Machinery for Operating
the same.
I, SIDNEY MANTHORP COCKBURN, of 66, Victoria Street, in the City of
Westminster, Engineer, 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 punkahs and to machinery for operating the same, and
is chiefly designed to simplify the construction, and increase the efficiency of such
machinery.
In devising machinery for this purpose, much difficulty has heretofore been
experienced in providing satisfactorily for the working of the punkah in a manner
similar to that in which this operation is usually effected by manual power.
I overcome this difficulty by providing for the operation of the punkah by
mechanism which will alternately impart the necessary movement to the punkah in
one direction, and permit the movement thereof in the reverse direction under the
action of gravity, and which will perform its work efficiently notwithstanding
variations in the length or rapidity of the swinging movement or oscillation of the
punkah.
For this purpose, I combine, with the punkah, an engine for operating the same,

page_text: which engine is so constructed and arranged that its action is controlled by the
punkah itself.
My said invention comprises the combination of an engine constructed with a
cylinder and piston, and suitable mechanism for connecting the said piston with
the punkah, all the parts being so arranged that a single stroke or movement of
the said piston will effect the movement of the punkah from one to the other end
of its stroke or swing.
My said invention, moreover, comprises the combination, with the controlling-
valve of the engine, of suitable means whereby the said valve will be operated by
the punkah itself, so that, whatever may be the length or the rapidity of the
swinging movement of the punkah; the said valve will be partially opened so as to
admit steam or other fluid under pressure into the cylinder when or immediately
after the punkah has terminated its return movement.
1 also provide a variable cut-off, whereby the fluid-pressure can be allowed to
act during a greater or less portion of the stroke or swing of the punkah.
My said invention also comprises other improvements hereinafter set forth.
In the accompanying drawings I have shown how my said invention may be
conveniently and advantageously carried into practice.
of
Figure 1 is a side elevation, partly in vertical central section, and
Figure 2 a vertical central section on the line a, c, Figure 1, showing one form
my improved punkah-engine combined with a suitable steam-generator.
Figure 3 is a plan of the said engine.
Figure 4 is a plan, and
Figure 5 a side elevation, both drawn to an enlarged scale, showing the controlling-
valve and its operating mechanism.
Figure 6 is a vertical section, and
Figure 7 a horizontal section on the line ',, Figure 6, illustrating the con-
struction of the controlling-valve.,
Like letters indicate corresponding parts throughout the drawings.
A is a steam-generator arranged within a casing B, which is mounted upon legs
or supports C, and which has an aperture 131 in its underside to permit the passage
to the said generator, of the flame from an oil or other lamp supported on a disc
or platform D secured to the said legs C. The generator A is made shallow and
of comparatively large diameter so that the extent of the available heating surface
will vary but slightly as the water-level, descends owing to the evaporation of the
water. By constructing the generator in this manner, I obtain an approximately
constant or uniform production of steam.
is a cylinder provided with a piston 6, the rod 61 of which is furnished with a
toothed rack c. This rack is geared with a toothed wheel mounted upon a
shaft d', which is supported in suitable bearings on the cover a' of the cylinder a.
On the said shaft d is also mounted the wheel e, around which the punkah-cord is
wound and to which one end of the said cord is attached. is a controlling-valve,
the casing of which is connected by a pipe with the steam-space of the
generator A, and whereby steam may be admitted through the pipe to the space
in the said cylinder beneath the piston; h is an exhaust-pipe connected with the
casing of the valve f, and whereby the space in the said cylinder above the
piston may be put in communication with the external atmosphere.
In the apparatus shown in the drawings, the valve is a piston equilibrium
valve. The said valve is so arranged that, when depressed below the position
indicated in Figures 5 and 6, it will admit the steam coming from the boiler A
through the pipe y and passage ƒª, into the cylinder below the piston through the
passage and pipe, and, when the said valve is raised above the position
indicated in Figures 5 and 6, it will put the lower end of the cylinder in com-
munication with the upper end thereof through the passage a², and also with the
external atmosphere through the exhaust-pipe h.
The controlling-valve and the variable cut-off hereinafter described, are
arranged to be operated by suitable devices in the rotation of the shaft d¹

page_text: alternately in either direction. For this purpose, the controlling-valve fis
connected by a link j, Figure 5, with the short arm of a lever attached to a
clip or clamp l, which is mounted upon the shaft d' and is held thereon, through
the medium of springs, tightly enough to ensure its rotation therewith for the
purpose of operating the controlling-valve except when held as hereinafter
described, whilst permitting rotation of the shaft independently of the said clip or
clamp while the latter is thus held. Suitable stops are provided for limiting the
movement of the lever and valve, and the ends of the said lever or the said
stops may, if desired, be provided with cushions to prevent noise. In the apparatus
shown in the drawings, the stops consist of a screw-nut m adjustable upon a screw-
threaded rod m' fixed in the cylinder-cover a', and a collar m² arranged to be moved
up and down upon the said rod, and connected therewith by a bayonet-joint so that
it can be secured in the position shown.
The said collar is acted upon by a
spring which tends to move it downward.
The cut-off device comprises an adjustable quadrant n mounted on a toothed
wheel which is fixed on the shaft p¹ and receives proper movement from the main
shaft by means of a toothed wheel 7 secured thereon. The said quadrant n is
arranged to act upon the lever k in such a manner as to cause the valve to cut-
off the supply of steam to the cylinder at any required point of the stroke of the
piston, according to the position given to the said quadrant. Another adjustable
quadrant n' is secured upon the wheel p for the purpose of operating the valve
to slightly open the exhaust when the piston has performed a predetermined
fraction of its up-stroke.
I provide suitable means for cushioning the piston as the punkah approaches
the end of its return stroke or swing, and for obtaining an initial pull upon the
punkah as soon as its return movement ceases. For this purpose, I find it
advantageous to provide the wheel p with a pin, stud or projection, which acts on
the lever at the proper time so as to cause the valve to close on the exhaust
side and to open on the steam side just before the end of the down-stroke of the
piston. The steam will then serve as a cushion for the piston and will exert an
initial force upon the same when the punkah has terminated its return stroke or
swing. The said cushion may be increased or diminished by varying the position
given to the said pin or stud r.
Another pin or studs is fixed in the wheel p for the purpose of limiting the
upward movement of the lever k as hereinafter described.
The piston-rod extends through a guide a³ attached to the cylinder-cover a',
and a spring is placed upon the upper end of the said rod, and is held in place by
means of a screw-nut t. This spring is sufficiently strong to arrest the descent of
the piston before it has terminated its down-stroke, which will be completed when,
but not until the said piston is acted upon by the punkah in the latter part of the
return stroke or swing of the same, as, and for the purpose, hereinafter specified.
The operation of my improved apparatus is as follows, ciz.:-When the apparatus
is at rest, the piston is held up by the spring t a short distance from the bottom
of the cylinder, the lever & being then in its lowermost position, so that the lower
end of the cylinder is open to the exhaust. To start the apparatus, the wheel e
and shaft dare first turned, by hand, in the reverse direction to that indicated by
the arrow in Figures 2 and 5, so as to cause the pin to raise the lever and
thus close the valve on the exhaust side and slightly open it on the steam side,
thus admitting steam to the cylinder a below the piston b. The said piston, being
forced upward by the pressure of the steam, imparts rotary motion, in the direction
indicated by the arrow 1, to the shaft d' and wheel e, and thereby operates the
punkah. In the first part of this movement of the shaft d', as the stud's rises, the
lever and clip turn with the said shaft, thereby further opening the valve j
until the free end of the lever comes against the collar or stop m²; the said
shaft d then continues its rotation without the said lever and clip. In such rotation
of the shaft d', the wheel p and quadrant turn in the direction indicated by the
arrow 2 in Figure 5. After the piston has performed a predetermined fraction

page_text: of its stroke, the quadrant n acts upon the lever & and, by depressing the same,
moves the valve into the position shown in Figure 6, thus cutting off the admission
of steam to the cylinder a. When the piston has moved through a further pre-
determined portion of its stroke, the quadrant acts upon the lever and, by
further depressing this lever, slightly opens the valve on the exhaust side. The
piston then begins to descend by gravity and turn the shaft d' in the reverse
direction to that indicated by the arrow 1, and, in the first part of this movement
of the said shaft, the lever k and clip / turn therewith and further open the exhaust
until the said lever comes against the nut or stop m. The downward movement
of the piston is arrested by the spring before it reaches the end of its down-
stroke. The engine performs its return stroke in less time than the punkah, thus
slackening the cord which connects it with the punkah. The engine then remains
at rest until the punkah has nearly terminated its return stroke or swing and has
tightened the said cord, when the punkah turns the said wheel so as to move the
piston downward to the end of its stroke. In the continued rotation of the shafts d'
and p', the stud acts upon the underside of the lever and raises the said lever
so as to bring the same into the upper position indicated by dotted lines in
Figure 5. The valve is thus depressed so as to close the exhaust and slightly
open the valve on the steam side, as at starting. The piston then again moves
upward, thus fully opening the steam supply, the upward movement of the said
lever k, as the piston moves upward, being controlled by the studs so as to avoid
the too sudden admission of steam. The operations above described are then
repeated.
The exhaust quadrant should be so adjusted as to ensure the opening of the
valve on the exhaust side before the piston ceases its upward movement, other-
wise the piston would remain stationary until the punkah-cord set it in motion, and
would consequently offer undue resistance to the return movement of the punkah.
If, however, the exhaust quadrant and pin should fail to act by reason of
shortness of the stroke performed by the piston, the engine will still work, though
not so smoothly or advantageously. The said quadrant and pin can, therefore, be
dispensed with, if desired.
The position of the nut or stop m determines the extent to which the exhaust
can be opened by the lever k, and consequently the speed of the piston in its
downward movement. Therefore, by adjusting the said nut or stop m, the speed
of the piston may be regulated as may be required to ensure its keeping time with
the movement of the punkah.
To keep the valve fin its central position while the apparatus is not working,
the collar in is turned through an angle sufficient to disengage it from the pin of
the bayonet-joint, and is allowed to descend under the action of its spring m³,
whereby the lever will then be held in or below the position indicated in full
lines in Figure 5.
I find it advantageous to arrange the cylinder a with its lower part within the
generator, so as to maintain the said cylinder at a high temperature. Moreover I
prefer to fill the piston with suitable non-conducting material to diminish the.
transmission of heat through the same.
I sometimes mount the apparatus above described upon a suitable base provided
with adjustable feet whereby it can be conveniently levelled when placed upon an
uneven floor.
The generator is heated either by an oil or other lamp placed in a casing
beneath it, or by means of a small gas-producer suitably arranged in the said casing,
or by other convenient means. The said casing may extend around and over the
generator, and is provided with a suitable flue or outlet furnished with a damper.
The capacity of the generator may be such as to hold sufficient water to last for
9 or 10 hours, or a feed-pump may be provided, to be worked from the engine.
If desired, compressed air or other fluid may be used in the engine instead of
steam, in which case the generator above described is not required.

page_text: 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 :-
First. The combination, with a punkah, of an engine the action of which is
controlled by the punkah itself, for the purpose above specified.
Second. The combination, with a punkali, of an engine having a cylinder and
piston, and so constructed and connected with the punkah that the said piston will
impart motion' to the punkah in its outward stroke or movement, but will perform
its return stroke or movement independently of the punkah, for the purpose above
specified.
Third, A punkal-engine so constructed that its piston, after being moved outward
to operate the punkah, will return independently thereof and will be again moved
outward when, but not until, the steam or other fluid is admitted to the cylinder
by the punkah in the latter portion of its return movement, substantially as herein-
before described and for the purpose specified.
Fourth. The combination, with a controlling-valve, of a lever for operating the
same, attached to a shaft by means of a clip or clamp secured thereon in such a
manner that the said lever will move with the said shaft during a portion of the
revolution thereof in either direction, for the purposes above specified.
Fifth. The combination, with the controlling-valve, of the operating lever and
the variable cut-off mechanism, substantially as, and for the purposes, above
specified.
Sixth. The adjustable exhaust quadrant so arranged that it will open the cylinder
to the exhaust when the piston has moved through a predetermined fraction of its
outward stroke, substantially as, and for the purpose, above specified.
Seventh. The combination, with the cylinder and the piston working therein and
suitably connected with the wheel for operating the punkah, of a spring whereby
the piston, when at rest, is held a short distance from the bottom of the cylinder,
and means whereby, in the movement of the said piston to the end of its down-
stroke by the punkah, the controlling-valve will be slightly opened for the admission
of fluid to the cylinder, substantially as, and for the purpose, above specified.
Eighth. The combination, in an apparatus for the purpose above specified, of a
steam-generator and an engine having the cylinder arranged partly within the said
generator for the purpose of maintaining the heat of the said cylinder, substantially
as described.
Ninth. The improved apparatus constructed substantially as described with
reference to the accompanying drawings and operating as, and for the purposes,
above specified.
Dated the 1st day of April 1805
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.