A New or Improved Excess Load Alarm or Safety Appliance for Use chiefly with Derrick or Jib Cranes,
Year: 1899

page_text: Date of Application, 7th July, 1899
- Complete Specification Left, 9th. Apr., 1900-Accepted, 16th June, 1900
PROVISIONAL SPECIFICATION.
A New or Improved Excess Load Alarm or Safety Appliance for Use
chiefly with Derrick or Jib Cranes,
-
We, ROBERT WILLIAM MONAHAN, of 375, Chester Road, Manchester, Assistant
Dock Superintendent, and HENRY BARSDORF, of 373, Chester Road, Manchester,
Engineer, do hereby declare the nature of our said invention to be as follows:-
In derrick or jib cranes as at present constructed no provision is made for
indicating to the engine man the limit of load that his machine will carry, and
as a consequence such cranes are often set to raise a load which with the jib in
one position they will just carry,. but which when the jib moves outwards they
are incapable of further sustaining, and in many cases cranes so, loaded have
been known to topple over or over-balance with fatal injury to life, and con-
siderable damage to the crane.
The purpose of our invention is to provide a simple contrivance by which an
audible signal or a visible indication, or both, will be given as soon as the
maximum lifting power is approached, and so guard against accidents.
To this end we employ a strong spring, spiral, volute, or other suitable char-
acter, tested to withstand compression equal, or almost equal to the maximum
load to be raised by the crane to which our invention is applied. This spring
we introduce into the length of the derrick chains or rods, or the liaulage chain;
or so place it as to allow of its being acted' upon by the load to be raised; and so
that when the crane is set to raise a load which exceeds the strength of the spring
the spring closes, or is compressed.
Such compression we utilise for operating the hammer of a bell or gong, open-
ing a steam whistle, shutting off steam to the engine, or turning on steam to a
brake, or otherwise indicating to the man in charge the approaching danger.
The means we prefer to employ for effecting the mounting of the spring con-
sists of a set of draw rods and Hanges, or the like, provided with loops or shackles
for connection to the derrick chain or other object through which the load is to
act upon the spring. A set of "bow" links might serve for holding the spring.
Upon a plate carried by, or adjacent to the flanges of the draw rods or bow
links, we mount a bell or gong, or trigger-lever, and upon one of the rods or
flanges we provide a projection or finger, which, when the spring is compressed!
operates upon the hammer of the bell, or the said trigger lever, and so gives the
audible signal or alarm.
In addition to giving an alarm we may utilise the compression of the spring
for operating a pointer moving over a dial marked with divisions or figures to
indicate "safety" and "danger."
Whilst thus specially applicable to derrick cranes our invention may be applied
to other cranes and haulage appliances in general, in which it is desirable to
indicate the approach of the maximum load.
In lieu of being tested to withstand the maximum compression as aforesaid
the spring may be tested to withstand only the minimum compression, and so
be utilised as a weight or load measurer with the alarm set to operate when the
1

page_text: tension or compression reaches or almost reaches the heaviest or other pre-
determined load. In this modification we prefer to connect the appliance to
the haulage chain, or direct to the load.
T
1
T1 1900
ROBERT WILLIAM MONAHAN.
HENRY BARSDORF.
By John G. Wilson & Co.,
Patent Agents to the Applicants.
A New or improved Excess Load Alarm or Safety Appliance for Use
chiefly with Derrick or Jib Cranes.
We, ROBERT WILLIAM MONAHAN, of 375, Chester Road, Manchester, Assistant
Dock Superintendent, and HENRY BARSDORF, of 375, Chester Road, Manchester,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
In derrick or jib cranes as at present constructed no provision is made for
indicating to the engine man the limit of load that his machine will carry, and
as a consequence such cranes are often set to raise a load which with the jib in
one position they will just carry, but which when the jib moves outwards they
are incapable of further sustaining and in many cases cranes so loaded have
been known to topple over or over-balance with fatal injury to life and con-
siderable damage to the crane.
The purpose of our invention is to provide a simple contrivance by which an
audible signal or a visible indication, or both, will be given as soon as the
maximum lifting power is approached, and so guard against accidents.
To this end we employ a strong spring,--spiral, volute or other suitable char-
acter, tested to withstand compression equal or almost equal to the maximum
load to be raised by the crane to which our invention, is applied. This spring
we introduce into the length of the derrick chains or rods, or the haulage chain,
or so place it as to allow of its being acted upon by the load to be raised and so
that when the crane is set to raise a load which exceeds the strength of the spring
the spring closes or is compressed.
T
Such compression we utilise for operating the hammer of a bell or gong, open-
ing a steam whistle, shutting off steam to the engine, or turning on steam to a
brake or otherwise indicating to the man in charge the approaching danger.
The accompanying drawing illustrates one arrangement of apparatus embody-
ing our invention, Tig. 1 being a longitudinal. section on line ab, Fig. 2a
plan and Fig. 3 transverse section on line c—d.
Fig. 4 illustrates a derrick crane in miniature with our invention applied
thereto. Fig. 5 illustrates a diagram of the apparatus as used for cutting-off
steam.
(A) is the spring aforesaid which we introduce into the line of the derrick
chain (33) and the compression of which we utilise for giving the desired' alarm
or signal.
The means we prefer for effecting the mounting of the spring consist of a set
of draw-rods (C) (D) (E) and flanges (E), (G) and (H), the latter of which, and
the draw rod (E) are provided with loops, liuks or shackles (I) and (J) for con-

page_text: nection to the derrick chain or other object through which the load is to act
upon the spring.
To protect the spring and rods from dust, etc., we enclose them in a sheet
metal casing (K) fastened into the flanges (F) and (H).
Upon a plate or bar (L) connected at its ends to the flanges (F) and (H) we
mount a mechanical bell, and upon the rod (E) or the flange (G) we mount a
finger, which projects through a slot (M) in the bar (L) and which, when the
spring (A) is compressed to a point which represents the approach of the limit
of compression for the maximum load, operates (directly or indirectly) upon the
hammer of the bell, and thus give an audible "signal"" or "alarm." Instead of
a mechanical bell we prefer an electrical bell in that its action is instantaneous,
and more easily timed or regulated, and in applying an electric bell we employ
a set of terminals (N) which we mount upon a block (0) carried by a plate (P)
above the slot (M) and secured at any desired point along the slot by wing clamp-
ing nuts (Q). To the block two further plates (R) and (S) are connected, but
each insulated from the other and at their extremity provided with small con-
tacts (T) and (U) which whilst the plates lie horizontally and parallel are held
clear of each other, and cause the bell circuit to be broken.
Upon the underside of the plate (S) we provide a rounded projection (V)
which extends through the slot (M) and lies in the path of the flange (G) which
has a slight inclined recess (G) to meet it.
It will readily be seen that by arranging the projection (V) at the point at
which the maximum compression of the spring (A) is reached, or almost reached
(or other predetermined point) the flange (G) will press against the said pro-
jection and pushing it up, or outwards, cause the contact (U) to touch the con-
tact (T) and thus complete the bell circuit and ring the bell.
In addition to giving an audible alarm we may utilise the compression of the
spring for operating a pointer (as shewn dotted in Fig. 1) and moving over a dial
or plate marked with divisions or, figures to indicate "safety" and "danger."
We may also utilise the compression of the spring for shutting off steam to
the engine of the crane, and thus bring the crane to a standstill automatically,
and for this purpose we employ a rod (W) adapted to slide through the
flanges (F) (H) and (G) fitted with adjustable collars (✗) and (Y) and provided
with a slot (W) through which one arm of a bell-crank lever (Y*) may project,
as shewn more clearly in. Fig. 1.
The other arm of the lever (Y) we connect by cords or chains to the handle
of a, by preference, double-beat or equilibrium valve (Z) (see Fig. 5) via an
intermediate bell-crank lever (Z). When the spring is compressed the abut-
ment of the flange (G) against the collar (X) causes the rod to rotate the bell-
crank lever (Y) upon its centre, and through the medium of the chains and
lever (Z) close the valve (Z) and thus automatically shut off steam to the engine
and bring the crane to a standstill.
With a reduction of the load, and the return movement of the flange (G) the
said valve (2) is, under the pull of a spring (Z) reopened and thus the engine
is restarted automatically. The valve (Z) is auxiliary to, and independent of
the usual stop valve (7).
Whilst specially applicable to jib cranes our invention may be applied to
other cranes and haulage or lifting appliances generally with which it is desir-
able to indicate the approach of the maximum load.
In lieu of being tested to withstand the maximum compression as aforesaid
the spring may be tested to withstand only the minimum compression, and so
be utilised as a weight or load measurer with the alarm set to operate when the
tension or compression reaches or almost reaches the heaviest or other pre-
determined load. In this modification we prefer to connect the appliance to
the haulage chain, or direct to the load.
Instead of the flanges (F) (H) and rods (C) (D) we may employ a strong
cylinder, but for lightness, and cheapness of manufacture, we prefer the rods.

page_text: Having now particularly described and ascertained the nature of, our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1: In an excess load or safety alarm for derrick and other cranes or haulage
appliances, a spring tempered, to resist compression equal to, or slightly less
than, the maximum load,, a set of draw-rods and flanges (or cylinder and draw-
rod) with looks and shackles, and means for utilising the compression of the
spring for giving an audible "signal" or "alarm" and regulating such alarm,
substantially as herein set forth.
2 In an excess, load or safety alarm for derrick and other cranes or haulage
appliances, a spring tempered to resist compression equal to, a slightly less than,
the maximum load, a set of draw-rods and flanges. (or a cylinder and draw-rod)
with hooks or shackles, means for giving an audible "signal" or "alarm" and
adjusting such signal, and means for giving a visible indication of "danger'
or "safety, substantially as set forth.
33:
33
3:In an excess load or safety alarm for derrick and other cranes or haulage
appliances, a strong spring tempered to resist compression equal to, or slightly
less than, the maximum load, a set of draw-rods and flanges (or a cylinder and
draw-rod) with hooks or shackles, and means for utilising the compression of
the spring for giving an audible signal and regulating such signal, for giving a
visible indication of " danger" or safety," and for shutting off steam to the
engine of the crane, substantially as herein set forth..
4: In an excess load or safety alarm for derrick and other cranes or haulage
appliances, a strong spring tempered to resist compression equal to, or slightly
less than, the maximum load, a set of draw-rods and flanges (or a cylinder and
draw-rod) with hooks or shackles, and means for utilising the compression of
the spring for shutting off steam to the engine of the crane, substantially as
herein set forth.
5: The construction, arrangement and combination of parts herein described
and illustrated on the accompanying drawing as and for the purposes herein set
forth.
ROBERT WILLIAM MONAHAN.
HENRY BARSDORF.
By John G. Wilson & Co., Fels.I.P.A.,
Agent for the Applicants, 55, Market Street, Manchester.