AN ALARM
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by the said David Younger at the
Office of the Commissioners of Patents on the 28th May 1879.
DAVID YOUNGER, of Woolwich, in the County of Kent, Smith.
HINGE."
" AN ALARM
The object of my Invention is an alarm hinge capable of being locked and un-
locked. When locked, it gives an alarm upon the least movement of the door,
without the power of the alarm giving medium being in any way spent, and
without the necessity of any winding up or unwinding.
In carrying my Invention into effect, I employ in the centre of the hinge a fluted
roller which can be made to revolve by means of any number of pauls suitably
arranged on one side of the hinge, and caused to come into and out of gear with
the fluted roller by means of any suitable locking and unlocking mechanism. On
the opposite side of the hinge a box is formed, which may be let into the
door or door post, the box containing a number of springs, combs, levers, or other
suitable appliances for producing sound in conjunction with the fluted roller when
the latter is revolved.
My alarm hinge is by preference so arranged, that it can be locked and unlocked
only when the door is wide open, or at right angles with the door post.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Younger in the Great Seal Patent Office on the 28th November
1879.
DAVID YOUNGER, of Woolwich, in the County of Kent, Smith.
HINGE."
"AN ALARM
The object of my Invention is an alarm hinge capable of being locked and un-
locked. When locked, it gives an alarm upon the least movement of the door,
without the power of the alarm giving medium being in any way spent, and
without the necessity of any winding up or unwinding.
In carrying my Invention into effect, I employ in the centre of the hinge a fluted
roller which can be made to revolve by means of any number of pauls suitably arranged
on one side of the hinge, and caused to come into and out of gear with the fluted roller
by means of any suitable locking and unlocking mechanism. On the opposite side of
the hinge a box is formed, which may be let into the door or door post, the box
containing a number of springs, combs, levers, or other suitable appliances for pro-
ducing sound in conjunction with the fluted roller, when the latter is revolved.
My alarm hinge is by preference so arranged that it can be locked and unlocked
only when the door is wide open, or at right angles with the door post.
My Invention will be clearly understood on reference to the accompanying Sheet
of Drawings, in which Figure 1 represents an alarm hinge as it appears externally.
A is the fluted or toothed roller which is centred on the pin B forming the axis
of the hinge, and carried by the ears C, C, and D, D, of the two halves E and F,
the half E being secured to the door post G, and F to the door H, as seen in
Figures 2 and 3. In these two Figures the door is shown wide open, in which
position the attachment of the hinge to the door and post is clearly seen.
The half E is provided with two or more pauls J, each formed with a nose K,
which can take into the fluting or grooves of the roller A by the pressure of its
spring L when the hinge is locked, as shown in Figure 4.
In Figure 5, these pauls are shown with their noses withdrawn from the flutings
in the roller A, in which position the hinge is unlocked.
The half F is formed with a box M containing a number of springs or combs N,
which press firmly upon the teeth of the grooved or fluted roller.
The springs or combs N are preferably arranged in layers over each other, the
greater the number of them the more powerful will be the alarm given.
The fluting or grooving of the roller A is preferably formed at a slight angle with
its axis, as this arrangement causes the springs or combs N to fall in rapid succession
on the teeth of the grooving by which the alarm will be greatly intensified.
In Figures 4 and 5, which iliustrate one mode of locking, a bolt P is shown which
when acted upon by a key inserted in the key hole Q locks or unlocks the hinge,
and puts it in or out of action as desired. This is produced by the nose R of the
bolt being arranged to allow the spring pauls J to take into the flutings of the
roller A for locking, and to lift the spring pauls J clear of the flutings for un-
locking.
Figure 6 is a back view of the hinge, and shows clearly the box I which contains
the spring pauls J; these may be arranged the whole depth of the hinge if desired,
as in the box M on the opposite half F.
The action of the hinge is simply as follows:-The hinge has only to be locked,
as in Figure 4, when on opening the door, the springs or combs N revolve on the
roller A, and its teeth as they escape the noses of the springs or combs N cause a
loud clicking noise to be produced, and so give a powerful alarm.
It is obvious that my Invention is susceptible of slight modification in detail,
without departing from its essential nature.

page_text: And having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim,-
The alarm hinge herein before described and substantially as shown in the
annexed Drawings.
In witness whereof, I, the said David Younger, have hereunto set my hand
and seal, this Twenty seventh day of November, One thousand eight
hundred and seventy nine.
DAVID YOUNGER. (L.S.)