Appliances for Giving Irregular Motions to Punkahs.
Year: 1889

page_text: Date of Application, 29th May, 1889
Complete Specification Left, 27th Feb., 1890-Accepted, 29th Mar., 1890
PROVISIONAL SPECIFICATION.
Appliances for Giving Irregular Motions to Punkahs.
We, SAMUEL ROBERT BAILDON, of 1, Whitefriars Street, and JAMES KERSHAW,
of 97 Wood Street, City of London, Gentlemen do hereby declare the nature of our
said Invention to be as follows:-
In the working of Punkahs, it is essential that an irregular motion be given to
them, that is to say :-that the Punkah shall be drawn rapidly in one direction and
be permitted to move slowly in the reverse direction for producing the necessary
disturbance of the heated or vitiated air of a room. The rapid movement creates a
partial vacuum behind the Punkah which permits of a quantity of fresh or cooler air
to follow; the surrounding air being also violently agitated and the room ventilated
to a greater degree than according to the present systems of Punkahs moving at
about the same speed in both directions.
The object of this invention is to effect the alternating fast and slow motions of
a Punkah mechanically, and for this purpose we affix the pull cord to an arm pivotted
to a stud at the opposite end, said arm being caused to vibrate by an eccentric,.
a catch-and-go lever, or equivalent appliance controlled or operated through or from
spring gear or a falling weight, the arc of vibration of the lever being adjustable by
the position of a stud on a disc or wheel or on a slotted bar.
If we employ an eccentric, we arrange on either side of it blocks, with pegs
which engage in slots of the eccentric. The blocks are on separate shafts one of
which is in connection with the spring driving mechanism, or of the falling weight,
the other shaft being in relation to the pull cord appliances.
If we employ a catch-and-go lever to actuate the pull cord lever we arrange a
stud or block thereon and this after depressing the pull cord lever over the desired
distance is shifted sideways by a wedge or inclined plate against which it bears, and
to prevent the spring gear or the falling weight when the pressure is released, from
racing, we affix a break or buffer within range for the purpose.
We may employ two eccentrically fitted gear wheels, said wheels having slots
for adjusting the distances from the shafts or centres, and so regulating the speed
of travel of the disc or appliance by which the pull cord lever is operated.
H. GARDNER,
166, Fleet Street, London, E.C., Agent for the said S. R. Baildon
and J. Kershaw.
COMPLETE SPECIFICATION.
Appliances for Giving Irregular Motions to Punkahs.
We, SAMUEL ROBERT BAILDON, of 1 Whitefriars Street, and JAMES KERSHAW, of
97 Wood Street, City of London, Gentlemen, 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 :-
In the working of Punkahs it is essential that an irregular motion be given to
them, that is to say-that the Punkah shall be drawn rapidly in one direction and
be permitted to move slowly in the reverse direction for producing the necessary
disturbance of the heated or vitiated air of a room. The rapid movement creates a
partial vacuum behind the Punkah which permits of a quantity of fresh or cooler air
to follow, the surrounding air being also violently agitated and the room ventilated
to a greater degree than according to the present system of the Punkah's moving
at about the same speed in both directions.

page_text: The object of this invention is to effect the alternating fast and slow motion of
a Punkah mechanically and for this purpose we affix the pull cord to a lever arm
pivotted to a stud at the opposite end, said arm being caused to vibrate by an
eccentric, a catch and go lever (or equivalent appliance controlled or operated
through or from spring gear or a falling weight, the arc of vibration of the lever
being adjustable by the position of a stud on a disc or wheel, or on a slotted bar.
If we employ an eccentric, we arrange on either side of it blocks with pegs
which engage in slots of the eccentric. The blocks are on separate shafts, one of
which is in connection with the spring driving mechanism, or of the falling weight,
the other shaft being in relation to the pull cord appliances.
If we employ a catch and go lever to actuate the pull cord lever, we arrange
a stud or block thereon and this after depressing the pull cord lever over 'the desired
distance is shifted sideways by a wedge or inclined plate, against which it bears and
to prevent the spring gear or the falling weight, when the pressure is released, 'from
racing, we affix a break or buffer within range for the purpose.
We may employ two eccentrically fitted gear wheels, said wheels having slots for
adjusting the distances from the shafts or centres and so regulating the speed of travel
of the disc or appliance by which the pull cord lever is operated.
Our invention will be more clearly understood by the annexed drawings.
Figure 1 shows a front elevation, and Figure 2 an end elevation of the
mechanism of one method for effecting the object in view, the casing being in
section.
A is a ring or disc rotatable in a frame B by the shaft C and gear D, E, F, G,
from a drum H having a rope I and weight suspended from it for giving the necessary
motion.
The disc A is slotted at K, K₁, and a sliding block or pin L attached to a side
plate M rides in the slot K said disc being eccentrically fitted with relation 'to the
shaft C, so that as the shaft C rotates, the block or pin L pulls the eccentric ring A
round the pin L having a free movement along the slot K. Co-axial with the
shaft is another shaft N also provided with a plate M¹ with pin or sliding block -L'
which rides in the other slot K₁ of the disc A for giving rotation to the second
shaft N and through it to the outside disc P thereby giving an oscillatory motion 'to
the Punkah pull lever Q to which it is loosely attached by the block R, this having an
independent motion on its pivot pin.
By the eccentric position of the ring or disc A to the two shafts C, N, an irregular
oscillatory motion is given to the pull lever Q, as follows; as the pin L of the shaft C
is close to the axis of the eccentric while moving round the lower half of the circle,
the motion of the Punkah is somewhat fast from the greater distance: the block L' has
to travel in the same period of time as the other block travels over the short distance
from its closeness to the axis, the outside disc having a higher rate speed during one
portion of its revolution to that of the other portion.
Figures 3 and 4 show side elevation and plan of a modified arrangement or
mechanism by which an alternating fast and slow movement can be given to a
Punkah. In this, the driven shaft has a pinion. F.mounted eccentrically upon it,
with a slot on which the wheel F has a sliding upward and "falling motion at each
rotation, another wheel E following this motion and remaining in gear as also with the
wheel'D on the axle of the disc P by which the pull: lever is moved to and fro, as
the disc P is revolving.
Figures 5 and 6 show another modified arrangement of apparatus for the same pur-
pose. In this, the shaft C as it rotates carries the slotted arm Tiround and according
to the adjustment of the block U in the slot so the lever Q is acted upon sooner for
later. The lever Qis of springy steel or has a joint in it, as at Figure 7, with a
spring V behind the joint which enables the lever to yield in passing down the incline
face of the post W shown separately at Figure 8 by which saidilever is pushed away
to escape the block U for a return of the Punkah by gravity.
To prevent the mechanism in the box racing when relieved of the weight of the
Punkah after being pulled somewhat rapidly, we fit a cam disc X on the shaft N and
-

page_text: is
to the side of the casing, we arrange a spring plug or buffer Y which becomes com-
pressed while the larger diameter of the cam X is passing round but which
pressure
removed while the lever is being pulled down by the block U, the buffer Y then riding
against the smaller diameter of the cam X.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what
we claim is :-
1. The particular arrangement and method of action of the appliances shown at
Figures 1 and 2 of the annexed drawings for producing an alternate fast with a slow
motion to Punkabs.
2. The particular arrangement and method of action of apparatus shown at
Figures 3 and 4 for giving an alternate fast with a slow motion to Punkahs.
3. The particular arrangement of apparatus for producing hit and miss, or alternate
motion to Punkahs by pressure and gravity in succession as described, with reference
to Figures 5, 6, 7 and 8 of the annexed drawings.
mi
228
1000
H. GARDNER,
166, Fleet Street, London, Agent for the said Samuel Robert Baildon
and James Kershaw.