IMPROVEMENTS IN SAFETY APPARATUS FOR GAS BURNERS
Year: 1883

page_text: LETTERS PATENT to The Honorable John William Plunkett of Dunstall Priory
in the County of Kent and of Park Square in the County of Middlesex
and John Cecil Hart of High Street Stratford in the County of Essex for an
Ti
PROVISIONAL SPECIFICATION left by the said John William Plunkett and
John Cecil Hart at the Office of the Commissioners of Patents on the
6th June 1883.
The Honorable JOHN WILLIAM PLUNKETT of Dunstall Priory in the County of
Kent and of Park Square in the County of Middlesex and JOHN CECIL HART of
High Street Stratford in the County of Essex "IMPROVEMENTS IN SAFETY
APPARATUS FOR GAS BURNERS
"
Our Invention has reference to the apparatus described in the Specification of
Letters Patent N° 643 granted to me the said John William Plunkett as of the
10th February A.D. 1882 and has for its object to provide means whereby the
necessity for holding the gas tap in position until the bar or rod or its equivalent
has expanded is obviated.
According to our said invention we provide a catch piece which is pivotted to
the framing in such a manner that when the tap is turned to open the gas supply
the said catch piece acts automatically to support the weighted arm of the tap and
retain the tap in its open position until the bar or rod has expanded by the heat
of the gas flame. The said bar or rod is preferably connected at one end only to
the framing so that its other end is opposite the lever upon which it acts. When
the said bar or rod expands it acts upon the said lever and brings it into a position
to support the gas tap upon the projection of the said lever as described in the
aforesaid Specification but the said lever also acts upon the said catch piece to turn
it out of position for supporting the weighted arm of the gas tap so that the said
arm is (after the rod or bar is expanded) no longer supported by the said catch
piece but by the projection of the said lever in the manner described in the aforesaid
Specification so that should the flame be accidentally extinguished the said gas tap
will be automatically closed as there described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John William Plunkett and John Cecil Hart in the Great Seal
Patent Office on the 6th December 1883.
The Honorable JOHN WILLIAM PLUNKETT of Dunstall Priory in the County of
Kent and of Park Square in the County of Middlesex and JOHN CECIL HART of
"IMPROVEMENTS IN SAFETY
High Street Stratford in the County of Essex
APPARATUS FOR GASBURNERS
"
Our Invention has reference to the apparatus described in the Specification of
Letters Patent N° 643 granted to me the said John William Plunkett as of the
10th February A.D. 1882 and has for its object to provide means whereby the
necessity is obviated for holding the Gas tap in position until the expanding bar
or rod or its equivalent has become beated sufficiently to retain the tap in its open
position as therein described.
And in order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of Drawings the same letters of reference
indicating corresponding parts in all the figures.
Figures 1 and 2 are elevations at right angles to each other of an apparatus
arranged according to our Invention and Figures 3 and 4 are elevations shewing
different positions as hereinafter described.
According to our said Invention we provide a counterweighted catch piece a
which is pivotted at a² to the framing b in such a manner that when the tap is
intentionally turned on to open the gas supply the said catch piece a acts autoina-
tically to support the weighted arm d of the gas tap d and retain the tap in its
open position until the bar or rod c has expanded by the heat of the gas flame.
The bar d has a projection d³ to rest upon the projection of the said catch piece a.
The said catch piece a is preferably placed as shewn so as not to be liable to catch
the projection d³ unless the tap be turned on deliberately. Figure 3 shews the
position when the gas is turned on. The bar or rod c is preferably connected by
a split or spring screw at one end only to the framing b so that its other end is
opposite the lever e upon which it acts. The framing b may be of the form shewn
to facilitate due expansion and contraction of the parts. When the said bar or
rod c expands it acts upon the said lever e and brings it into a position to support
the arm of the gas tap upon the projection e* of the said lever e as described in the
aforesaid prior specification but the said levere also acts upon the weighted tail
end a³ of the said catch piece a to turn it upon its centre a² out of position for
supporting the weighted arm d of the gas tap so that the said arm d is (after the
rod or bar c is expanded) no longer supported by the projection d³ resting upon
the said catch piece a (as in Figure 3) but by the roller d' resting upon the projec-
tion e² of the lever e in the manner illustrated in Figure 4 and after the manner
described in the aforesaid Specification so that should the flame be accidentally
extinguished the said gas tap will be automatically closed as there described by
reason of the bar c contracting and the arm d being consequently released. The
catch piece a is forcibly removed and held out of range of the pin d³ by the lever e
(when the latter is brought into position by the expansion of the bar c to support
the lever d) and cannot be made to re-engage with the pin d³ while the gas is full
The incline of the projection e² may be of such a shape (as shewn) that as the
rod c expands owing to excessive heating due to the gas blowing the said incline
lifts the arm d and partially closes the tap to lessen the supply of gas. The arm d
is preferably fitted to the plug of the tap in such a manner that the tap can if
on.

page_text: required be partly turned in the said arm so that the flame can to a certain extent
be regulated. This fitting of the arm and plug will of course be made with
sufficient friction to ensure the arm being raised when the tap is opened and to
insure the said arm closing the said tap when it operates as a safety device. In
some cases when our safety device is applied to gas brackets already provided with
taps the thumb piece for turning the tap of our safety device may be dispensed
with and the lever d may be formed in one with the plug of the tap. When a
small light is to be maintained or a smaller burner is to be used and it is desired
that the safety apparatus shall act we may provide socket pieces of suitable lengths
according to the size of burner required which can be screwed into the burner
socket and carry the burner as indicated in Figure 4 so as to bring the flame
sufficiently near to the bar c to expand it.
It is obvious that the safety device hereinbefore described may be applied to gas
burners generally whether they be used for lighting or heating for example those
of cooking ovens or the like.
Having now described and particularly ascertained the nature of our said
Invention and the manner in which the same is or may be used or carried into
effect we would observe in conclusion that what we consider to be novel and
original and therefore claim as the Invention sccured to us by the herein before in
part recited Letters Patent is :-
First-The arrangement or combination of parts constituting the safety apparatus
for gas burners, substantially as herein before described with reference to the
accompanying drawings.
Second-In safety apparatus for Gas burners the employment of a catch piece,
or its equivalent, which retains the Gas tap in position when first turned on, but
which is afterwards automatically removed and retained in its removed position,
substantially as and for the purpose hereinbefore described with reference to the
accompanying Drawings.
In witness whereof I the said John William Plunkett on behalf of John Cecil
Hart and myself have to this our Specification set my hand and seal this third day
of December One thousand eight hundred and eighty three.
TATT