IMPROVEMENTS IN AUTOMATIC VENTILATORS
Year: 1878

page_text: LETTERS PATENT to William Symonds, junior, and George Barnabas Symonds,
both of Potton, in the County of Bedford, for the Invention of "IMPROVEMENTS
IN AUTOMATIC VENTILATORS."
Sealed the 25th March 1879, and dated the 26th September 1878.
PROVISIONAL SPECIFICATION left by the said William Symonds and George
Barnabas Symonds at the Office of the Commissioners of Patents on the 26th
September 1878..
WILLIAM SYMONDS, junior, and GEORGE BARNABAS SYMONDS, both of Potton, in
the County of Bedford. " IMPROVEMENTS IN AUTOMATIC VENTILATORS."
This Invention relates to improvements in the construction of ventilators for
conservatories and other horticultural buildings, public, private, and other buildings,
incubators, and the like, the object of the improvements being to render such
ventilators automatic in their action and simple in construction, and the Invention
consists in the employment of electricity for operating the ventilators by means of
an arrangement of mechanism constructed as herein-after described.
In carrying out our improvements we employ a louvre board or plate pivotted
in a suitable frame, and when in its normal position it occupies an angle of forty-
five degrees or thereabouts; one of the pivots of the louvre extends through the
frame and passes through a metal disc or plate, the upper periphery of the disc or
plate being provided with two notches or their equivalents for the purpose of lock-
ing the ventilator as herein-after described. Either behind or in front of the said
disc is placed a disc of suitable non-conducting material placed on the same pivot or
arbor as the larger disc, such smaller disc forming with or without its springs a
contact maker and breaker. On the upper portion of the periphery of the contact
disc is a plate of metal connected with one of the poles of a suitably placed battery,
and the discs are connected by means of a cranked connecting rod with the arma-
ture of a number of electro-magnets arranged in pairs, one set of magnets being for
opening the ventilator and the other set for closing the ventilator; the springs of

page_text: the contact maker and breaker are connected with the electro-magnets in the usual
manner. Above the larger disc we place a pivotted armature provided with a
projection or catch for taking into the herein-before described notches in the disc,
and above this armature is placed a pair of electro-magnets, connected respectively
with and operating simultaneously with the opening and closing electro-magnets
herein-before described. We employ an ordinary maximum and minimum electric
thermometer, suitably connected with the battery and the electro-magnets.
.
By this arrangement and construction of apparatus it will be understood that,
the parts being in their normal position, that is to say, the louvre being closed, if
the temperature rises the mercury in the maximum tube rising will make contact
with the wire therein and will complete the circuit, thereby causing one set of the
electro-magnets to attract the armature and operate the connecting rod; at the
same time the lock magnets will attract the herein-before described pivotted arma-
ture, the tooth of which will be released from its catch, and the disc will be allowed
to partly rotate, moving with it the louvre; at the completion of the stroke the
circuit is broken and the magnets cease to act, and the locking armature falls into
a notch in the disc and keeps the ventilator open. On the temperature falling and
contact being made between the mercury and the wire in the ininimum tube, the
circuit is again completed, and the opposite pairs of magnets being put in action
the reverse movement to that herein-before described takes place and the ventilator
is closed and locked in that position.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Symonds and George Barnabas Symonds in the Great Seal
Patent Office on the 26th March 1879.
WILLIAM SYMONDS, junior, and GEORGE BARNABAS SYMONDS, both of Potton, in
the County of Bedford. "IMPROVEMENTS IN AUTOMATIC VENTILATORS."
This Invention relates to improvements in the construction of ventilators for
conservatories and other horticultural buildings, public, private, and other buildings,
incubators, and the like, the object of the improvements being to render such venti-
lators automatic in their action and simple in construction, and the Invention
consists in the employment of electricity for operating the ventilators by means of
an arrangement of mechanism constructed as herein-after described.
In carrying out our improvements we employ a louvre board or plate (or more
than one louvre may be employed) pivotted in a suitable frame, and when in its
normal position it occupies an angle of forty-five degrees or thereabouts; one of the
pivots of the louvre extends through the frame and passes through a metal disc or
plate, the upper periphery of the disc or plate being provided with two notches or
their equivalents for the purpose of locking the ventilator as bérein-after described.
Either behind or in front of the said disc or plate is placed a cam or disc, or its
equivalent, of suitable non-conducting material (or insulated) placed on the same

page_text: pivot or arbor as the larger disc, such smaller disc or cam forming, in combination
with a spring and cam lever arrangement on each side thereof, a contact maker and
breaker; or a simple spring may be employed.
Each of the spring rods of the contact maker and breaker is connected with an
electro-magnet, herein-after called the lock magnet, and also with one of a pair of
electro-magnets, herein-after called the opening and shutting magnets, and the discs
are connected by means of a cranked connecting rod or rods with the armature of
the said opening and closing electro-magnets which are arranged in pairs, one set
of magnets being for opening the ventilator and the other set for closing the
ventilator.
Above the larger disc we place a pivotted armature provided with a projection
or catch for falling or taking into the herein-before described notches in the disc,
and above this armature is placed the said lock electro-magnet connected respec-
tively with and operating simultaneously with the opening and closing electro-
magnets herein-before described. We employ an ordinary maximum and minimum
electric thermometer suitably connected with the battery and the electro-magnets.
But to make our Invention better understood we will proceed to describe the
same by reference to the accompanying Drawing, in which Figure 1 is an elevation
of an automatic ventilator constructed according to our improvements; Figure 2, a
sectional end view shewing the position of the mechanism when the ventilator is
closed; Figure 3, similar view when the ventilator is open; Figure 4, diagram
shewing the connections of the mechanism with the thermometer and battery.
Similar letters in all the Figures represent similar parts.
f
a, a, is a suitable frame in which is pivotted a louvre board or plate 6 of any
suitable material; one of the pivots e of the louvre b extends through the frame, as
shewn in Figure 1, and serves to carry the metal lock plate d; e, e', are the notches
on the periphery or upper edge of the lock plate d; f is the cam or disc behind the
said plate & and also fixed on the pivot or arbor c; on each side of the said cam
is pivotted a curved rod, marked g and g' respectively, the lower ends g², g³, of
which rods are tipped with platinum and serve, in combination with the blocks h, h',
(also tipped with platinum) to make and break contact as herein-after described;
i, i, are levers pivotted at x, x¹, each of which levers has a cam, marked 18 and 1³
respectively, at its outer end for raising the said curved rods g, g¹, for breaking
contact as herein-after described; ; is the electro-magnet which we call the lock
magnet and which is permanently connected with the battery and with the spring
rods g, g', as shewn in Figure 4; k, k', is the pair of electro-magnets which we call
the shutting and opening magnets respectively, the block h being connected with
the shutting magnet k and the block h¹ with the opening magnet k', which is also
connected with the maximum tube t of the electric thermometer A, and the
magnet with the minimum tube of the thermometer, the said thermometer
being connected as shewn with the opposite pole of the battery to that which is
connected with the lock magnet j; 1, 1, are the cranked connecting rods, the rod Z
being fixed to the armature m placed between the opening and shutting mag-
netsk, k, the other rod l¹ being suspended from the pivot n, the two rods being
connected by the pin o; 8 is a pin for connecting the rod to the lock plate d.
Instead of this arrangement of the connecting rods, any other suitable, arrangement
may be employed. p is the pivotted armature placed between the lock magnet j
and the periphery of the lock plate d; q is the projection or catch of the arma-
ture p; and r is a spring pressing the armature on to the plate d.
By this arrangement and construction of apparatus it will be understood that if
the connections be made with the thermometer and battery, as herein-before
described and shewn in the diagram, Figure 4, and the parts being in the position
shewn in Figure 2, that is to say, the ventilator being closed, let it be assumed
that the temperature rises to the point at which the ventilator is to be opened, and
which for example may be taken at sixty degrees, at which point the mercury in
the maximum tube of the thermometer will make contact with the wire therein
connected with the opening magnet ¹, and the circuit being thus completed the

page_text: current from the battery will pass through the magnet ; so as to attract the arma-
ture p and draw its tooth or catch 9 out of the notch e' of the plate d, and
simultaneously the current passing through the spring rod g and block h¹ into
the opening magnet will thereby attract the armature m, which will move with
it the connecting rods 7 and 1, the latter of which by means of the pins will
partially revolve the lock plate d and the cam f, which cam fraises the lever i¹, so
that the cam thereof will raise its lever g' so at to break contact with its block h';
at the same time the lever i being released from the cam f, the curved rod g will be
carried down by its spring so as to make contact with the block connected with
the shutting magnet k all into the position shewn in Figure 3, and the said lock
plate d and cam f being fixed to the pivot c of the ventilator b, it follows that this
latter moves with the plate d and will be consequently opened as shewn by the
dotted lines, Figure 3, and the catch q of the armature p falling into the notch e of
the plate & will lock it in that position. Should the temperature fall the mercury
in the minimum tube u of the thermometer will come in contact with its wire so as
to complete the circuit with the shutting magnet, and the same action will take
place to that herein-before described, but in the opposite direction.
Having thus described the nature of our said Invention and the manner of
performing the same, we would have it understood that we do not confine ourselves
to the precise details herein laid down and shewn in the Drawing, as the same may
be varied without departing from the peculiar character of our Invention, as, for
example, the form of contact maker and breaker may be altered, and other forms of
connecting rods for operating the lock plate may be employed, also the shape of the
louvre, which may be round or oval and may be placed either horizontally or
vertically according to the purpose for which the ventilator is used, and more than
one louvre may be employed, but what we do claim is,-
Firstly. The general arrangement and construction of the improved automatic
ventilator operating substantially as herein-before described and represented in the
accompanying Drawing.
Secondly. The peculiar construction of the lock plate in combination with the
toothed armature for locking the ventilator in its open or closed position, as herein-
before described, and represented in the accompanying Drawing.
Thirdly. The spring rod and cam lever arrangement for making and breaking
contact, as herein-before described, and represented in the accompanying Drawing.
In witness whereof, I, the said George Barnabas Symonds, for and on behalf
of myself and the said William Symonds, junior, have hereto set my
hand and seal, this Twenty-fifth day of March, in the year of our Lord
One thousand eight hundred and seventy-nine.
Witness,
G. F. REDFERN,
4, South Street,
Finsbury.
GEO. B. SYMONDS. (L.S.)