Automatic Alarm
Year: 1898

page_text: Automatic Alarm
We, ALEX POPE, of 94, Kings Road, Kingston-on-Thames, Associate Member
of the Royal Institute of British Architects, and ARTHUR BERTRAM RAYNER, of 68,
Oakfield Road, Finsbury Park, London, N., Associate Member of the Institute
of Electrical Engineers, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an electrical alarm for indicating when any one of the
gates or other barriers to the entrances of a lift well happens to be opened during
the absence, or to be left open after the departure, therefrom of the lift cage the
object of the invention being to give such warning of the fact as to prevent danger
of accident by persons falling down the well.
With this object the invention consists in providing for each gate or barrier
an electrical circuit (comprising an alarm bell and battery which may be in
common for the circuits of all the gates) there being interposed in each such
circuit two automatic circuit closers or points at which the circuit is automatically
made and broken, and in providing on the gate or barrier and on the lift cage,
means whereby when the gate is closed, and when the lift cage is at the level
of the entrance to which such gate appertains, the circuit will be broken at both
of those points, so that in either event (i.e. closure of the gate or presence of the
lift cage) the circuit will be broken at one of such points, but should the cage be
moved away without the gate being first closed, or should the gate be opened in
the absence of the cage the circuit will be complete at both points and the alarm
will be sounded.
The circuit closers may be conveniently formed of pairs of spring contacts the
springs of each pair tending to close together and the means of breaking contact
may consist of wedge-like separating pieces of insulating material mounted on the
gate and on the lift in position to come between and separate the respective pairs
of springs when the gate is closed or the cage is present.
The ordinary lift call bell and indicator may be combined with the same circuits,
so as to afford a means by constant use of testing the working condition of the
alarm circuits as well as of indicating to the lift operator the particular gate in
respect of which the alarm has been sounded.
1 1
To 1808
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.

page_text: f is a contact strip screwed to the floor of each landing in the path of a contact g
mounted at the foot of the gate so as to rub or roll on the contact f when the gate-
is opened, the connection between ƒ and g being broken when the gate is closed.
The pair of spring contacts d d and the contacts f and g are connected in circuit
with a bell h and battery i as shewn in Figure 1. If the circuit be partly through
the gate itself, as might be the case with a metallic expanding gate of the kind
shewn in Figure 7, the contact of would not be directly beneath the gate but in
front thereof, the contact g being offset to correspond as shewn in Figures 8
and 9. And in order to ensure good conductive contact, notwithstanding uneven-
ness of the strip f by wear, the contact g is formed of a roller pivoted in a plunger
pressed upon by a spring and sliding with a pin and slot connection in a guide
socket or holder.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed we declare that what we
claim is;-
The combination with a lift cage and with each gate controlling access thereto
at different landings, of an electric alarm circuit having two circuit closers in
series in said circuit and means whereby the circuit is broken at the one closer
when the cage is at that landing and at the other closer when the gate is shut so
that when the contrary conditions concurrently prevail, the circuit will be closed
at both places and the alarm will be sounded substantially as specified.
Dated this 3rd day of March 1899.
A. M. & WM. CLARK.
Chartered Patent Agents, 53, Chancery Lane, London.