AN IMPROVED DRAW OFF VALVE
Year: 1885

page_text: I SAMUEL WILKERSON of Bassingbourn in the County of Cambridge, Agricultural
Engineer do hereby declare the nature of the said invention for "AN IMPROVED
DRAW OFF VALVE" to be as follows:
My invention relates to an improved arrangement of mechanism for operating
and particularly for locking in the closed position, the discharge or draw off valve
of a water cart or barrel.
The valve has an indiarubber collar and fits in a seat in the end of the outlet
pipe to which the valve is loosely hinged at one side. The valve is jointed by ears
at its back to the end of a lever fulcrumed on a bail or pair of connecting links
pivoted to the pipe, whereby the valve is pressed forcibly in its seat by a sort of
toggle action when the centres of the bail or links and of the lever and valve are
brought into a straight line. A stop is provided which limits the. motion in one
direction and by arresting the parts immediately after passing the dead point or
line of centres the valve is effectually locked in the closed position and cannot be
opened by internal pressure the india rubber packing of the valve having sufficient
elasticity to ensure a tight joint.

page_text: I SAMUEL WILKERSON of Bassingbourn in the County of Cambridge Agricultural
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 an improved means of operating valves for controlling
the flow of water or other liquid into or from any vessel such as a water cart or
barrel cistern or other receptacle containing any liquid to be drawn off including
the mud valves or plugs of steam boilers.
The valve is seated in the mouth of the outlet or inlet pipe to which it is loosely
hinged or pivoted. The valve is loosely connected at its back to the end of a lever
fulcrumed between a pair of connecting links pivoted at their other ends to the
pipe whereby the valve is pressed forcibly to its seat by a sort of toggle action
when the centres of the bail or links and of the lever and valve are brought into
a straight line. The motion is limited by a stop which arrests the parts immediately
after passing the dead point or line of centres, the valve being in this manner
effectually held closed against, internal pressure.
Reference is to be had to the accompanying drawings forming part of this
specification wherein figure 1 represents a side view of the valve in the closed and
open positions, figure 2 a plan of the same. Figure 3' shows a side view of
a modification. Figures 4, 5 and 6 show face side and top views of another
modification. Figure 7 shows the valve as applied to a water cart.
The same letters of reference indicate the same parts in all the figures.
a is the pipe mouth to which the valve is applied, b is the valve, c the lever
and d d the links for operating it. The pipe a is usually fixed outside the vessel
from which the liquid is to be drawn off but in the case of a water cart, it may be
fixed to the inside, the whole of the valve gear being contained within the cart
body and the lever c being operated by a chain, as shown in the sketch view
figure 7. The mouth of the pipe a is slightly flared to form a seat for the valve b,
which may have an india rubber collar or packing ring e around it or other packing
having sufficient elasticity to ensure a tight joint. Or in case of a solid face valve
the necessary elasticity may be obtained by making the links d of spring steel and
of curved or other form to enable them to yield slightly.
The lever e works on a fulcrum at f where it is pivoted between the outer ends
of the links d and in figures 1 and 2 it is jointed at g by its inner or shorter
member to ears on the back of the valve, which is loosely hinged at h, to the upper
side of the outlet pipe a. The links d are pivoted at their other ends i to either
side of the outlet pipe. k is a crosspin on the lever c which comes against the
links d, immediately the centre of the fulcrum joint f has passed below the straight
line passing through the centres g and i, and so prevents any further downward
motion of the lever c. In this position of the parts, any internal pressure against
the face of the valve tends to move the outer end of the lever downwards but this
is prevented by the stop k so that the valve is locked in the closed position whilst

page_text: by lifting the outer end of the lever c (which may be weighted) and so moving the
fulcrum f to the other side of the line of centres, the valve can be readily opened,
the parts then assuming the position represented in dotted lines in figure 1.
In figure 3 the inner or shorter member of the lever c is not pin jointed at g, to
the back of the valve; but is curved and passes through a staple on the back of the
valve, the action being substantially the same as in the other arrangement.
In figures 4, 5 and 6 a square valve and seat are shown and the pipe has two
side cheeks to prevent the liquid spreading laterally and between which the valve
works the operative parts being similar to those before described, and needing no
further description. In figure 7 the valve is shown as applied to the outlet of
a water cart the valve and its mechanism (which is similar to that shown in
figures 1 and 2) being placed within the cart and operated by cords or chains m n
running round guide pullies to the driver's seat.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
The combination with a valve of a lever c and links d jointed together and to
the valve and its seat respectively, and the stop, the whole combined for
operation substantially as herein described and represented in the several figures
of the drawings.