Improvements in or connected with Automatic Fire Extinguishers.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with Automatic Fire Extinguishers.
I, OTTO HOFFMANN, of West View, 18, Wellington Road, Withington, near
Manchester, in the County of Lancaster, Engineer, do hereby declare the nature
of this invention to be as follows:-
My said invention relates to improvements in or connected with automatic
fire extinguishers of the "Sprinkler" type, and consists of a system of levers to
maintain the valve of the spindle upon its seat which levers serve also to effect a
rapid opening of the valve when required.
In carrying my invention into effect I form the sprinkler head with a valve
seating to accommodate a valve preferably made of aluminium. To support the
valve upon its seating in the sprinkler head I provide an inclined lever one end
sitting loosely in a bearing formed in or about the centre of the usual disperser
diaphragm. At about the centre of this inclined lever I form a notch or other
support for a short lever inclined in a contrary direction to the supporting lever.
One end of this short lever rests in the notch, the other end bears directly
against the valve. The sprinkler head is formed with an annular recess or groove,
within which groove is placed the hooked or bent end of another lever. The end
of the lever resting in the bearing in the disperser diaphragm carries a bolt and
the upper end of this lever bears against the hooked lever.
The bolt is arranged to be passed through a slit or hole in the lower end of
the hooked lever.
By pressing the lower end of the hooked lever inwards so as to pass the bolt
through the slit the two short angularly disposed levers are pressed inwards with
an elastic pressure thus securely holding the valve upon its seat. In this position
the bolt is secured to the hooked lever in any suitable manner by means of fusible
metal. As the two short angularly disposed levers are thrust by the hooked lever
in a direction tending to assume a straight line, not only is the leverage exerted
upon the valve very great, but also an elastic pressure is brought to bear upon
them.
When therefore the fusible metal is melted by the increase of temperature
caused by a fire, the hooked lever immediately springs outwards and the angular
valve supporting levers are thus caused to at once collapse thus opening the
valve.
The sprinkler head may be placed either above or below the water pipe as
the elastic pressure exerted by the hooked lever is fully adequate to enable it to
effect its object in either position.
The gist of my invention consists in the provision of two levers disposed at
contrary angles for supporting the valve on its seat, which levers are thrust inwards
with an elastic pressure by a third lever. I do not therefore confine myself to the
exact arrangement described as the same may be varied in detail without departing
from the spirit of my invention.

page_text: The method also of locking the levers in position by means of fusible metal may
be varied.
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E. K. DUTTON & Co.,
Chartered Patent Agents,
5, John Dalton Street, Manchester.
I, OTTO HOFFMANN, of 18, Wellington Road, Withington, near Manchester,
in the County of Lancaster, Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement and accompanying drawings:-
My said invention relates to improvements in or connected with automatic
fire extinguishers of the " Sprinkler" type, and consists mainly of a system of
levers and struts to maintain the valve of the spindle upon its seat, which levers
and struts serve also to effect a rapid opening of the valve when required.
And in order that my invention may be properly understood I will describe
the same with reference to the accompanying sheet of drawings.
In the said drawings.
Fig. 1 represents in outside elevation a sprinkler constructed in accordance with
my invention.
Fig. 2 is a view of the arrangement of struts and levers at right angles to Fig. 1.
Fig. 3 is a sectional elevation of the sprinkler showing more clearly the arrange-
ment of struts.
Fig. 4 is an outside elevation of the sprinkler at right angles to Fig. 3 after
the disruption of the parts and the fall of the valve.
Fig. 5 is a diagramatic view of the arrangement of struts showing the points
where power is exerted.
In carrying my invention into effect I form the sprinkler head with a valve
seating to accommodate a valve a preferably made of aluminium. To support the
valve a upon its seating in the sprinkler head I provide an inclined strut 6 the
lower pointed end 6' of which sits loosely within a recess c formed in the end of an
adjusting screw d. This regulating screw d passes through the centre of the
usual disperser diaphragm e. Instead of an adjustable screw a fixed projection
may be employed if desired.
At about the centre of the inclined strut b I form a notch or support 62 upon
which rests a short strut f which is inclined in a contrary direction to the strut b.
The lower end of the strut f rests upon the notch or support 63 of the strut b the
upper end being pointed or formed with a projection f entering a recess a¹ of
the valve a.
Within the sprinkler head is screwed a ring 9 formed with an annular groove
or recess within which I place the hooked end of an arm h. Instead of a
separate ring g I might form the groove g¹ out of the solid metal of the sprinkler
head. The lower end of the strut b is provided with a studi and the upper end of
this strut bears against the hooked arm 'h, as will be clearly seen from an inspection
of the drawings. The stud i is arranged to be passed through a slit h¹ formed at

page_text: the lower end of the arm h...By pressing the lower end of the arm h inwards,
the latter, bearing upon the upper end of the strut b, causes the two short angularly
disposed struts bf to be pressed inwards with an elastic pressure, thus securely
holding the valve a upon its seat. The pressure may be increased by screwing
up the regulating screw d which will have the tendency to increase the relative
angle of the struts 6 and f. The stud i having been passed through the slit h¹ of
the arm his secured by means of a wedge j, fusible metal being employed to
maintain the wedge in position.
The disperser diaphragm e is connected to the head of the sprinkler by hangers k
one of these hangers k being shown broken away in Fig. 1 to more clearly show the
arrangement of levers.
From an inspection of the diagram Fig. 5 it will be noted that on pressing
the lower end of the long arm h inwards in the direction of the arrow the pressure
is communicated to the top of the arm h (at the point where the hooked end rests
in the annular recess) in the direction of the arrow 1, and the pressure is com-
municated to the top of the strut b exerting a force in the direction of the arrow 2.
The force is thus communicated to the centre of the strut b at the point and in
the direction of the arrow 3 and also in an upward and downward direction as
shown by the arrows 4 and 5. As the pressure thus applied to the hooked arm
thrusts the struts bf in a direction tending to make them assume a straight line,
on the lazy-tongs principle, the leverage exerted is not only very great, but also
an elastic pressure is brought to bear upon them.
When therefore the fusible metal is melted by the increase of temperature
caused by a fire, the wedge is at once ejected from the stud i, the hooked arm h
springs outward and the angular, valve supporting struts bf at once collapse and
the valve is opened by the water pressure as shown in Fig. 4. The sprinkler head
may be placed either above or below the water pipe as the elastic pressure exerted
by the hooked arm h is fully adequate to effect the complete disruption of the
supporting parts in any position in which the sprinkler head may be placed.
I do not confine myself to the exact method of securing the supporting parts by
the fusible metal as described as this may be varied. The method shown however
has distinct advantages.
For instance, it is found in practice that on continued exposure to the atmo-
sphere fusible metal becomes oxydised and softened thus rendering the sprinkler
liable to be brought into action when not required, simply by being unable to
withstand any pressure which may be exerted upon it.
By employing a wedge held in position by the fusible metal, the fusible metal
entering the stud on each side of the wedge is protected to a very large extent
and shielded from atmospheric contact. In case therefore any excess of the
fusible metal outside the stud should be effected by atmospheric influences the
fusible metal in the stud being protected as described is unaffected thereby and
is sufficient to retain the wedge in position until melted by a dangerous increase
of temperature.
The stud and wedge j are by preference made of copper or other metal rapidly
conducting heat.
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:-
1. The improved automatic fire extinguisher or "Sprinkler" constructed, arranged
and acting in the manner as described and illustrated.
2. In a sprinkler of the indicated nature the angularly disposed struts b, f
arranged as set forth and thrust and held with an elastic pressure by the agency
of the arm h in a direction tending to make the said struts assume a straight
line on the lazy-tongs principle, so that pressure is exerted upon the valve and
upon an abutment opposite thereto to maintain the valve securely upon its seat, the
arm h on the melting of the fusible metal springing outwards or otherwise falling
away so as to bring about the complete disruption of the valve supporting struts,

page_text: and allowing the valve to be forced from its seating by the water pressure sub-
stantially as described and illustrated.