Improved Weighing Machine adapted to be used in conjunction with a Crane or Hoist for Weighing the Loads whilst Raising them.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improved Weighing Machine adapted to be used in conjunction with
a Crane or Hoist for Weighing the Loads whilst Raising them.
I, JAMES YATE JOHNSON, of No. 47, Lincoln's Inn Fields, in the County of
London, Gentleman, do hereby declare the nature of this invention (a communica-
tion to me from abroad by the Joint Stock Company "Eisenwerk (vormals Nagel &
Kaemp) Actien-Gesellschaft," of Uhlenhorst, near Hamburg, in the Empire of
Germany) to be as follows:-
Many attempts have been made to combine cranes and winches with weighing
machines designed substantially as follows:-
At a convenient point of the path of the rope or cord there has been situated
a roller, pulley or drum, supported by one end of the beam of a balance; over
which roller, pulley or drum the
rope or chain was passed in such
a manner, that the pressure exercised upon the roller, pulley or drum
by the bend or turn of such rope or chain could be ascertained at
the opposite end of the beam, either by means of weights placed
upon a scale, or by a weight or runner sliding along the beam itself; or, by reading
off the amount of pressure from the extent of the deflection of the balance-beam;
which deflection would take place owing to the varying pressure of the said roller,
pulley or drum wherever the beam was poised in a constant or uniform manner,
by means of either a weight or spring.
Such weighing apparatus would have been a great convenience, since it would
enable the crane-driver himself to weigh the loads as they were raised or lowered
by the crane, instead of necessitating the attendance of a special attendant for
weighing and involving a proportionate loss of time. All weighing machinery of
this kind has, however, proved unsatisfactory, inaccurate and unreliable generally.
I believe the reason for the indications of those machines being unreliable is, that
as the load is being lifted, the knife-edges of the weighing machine have to be
made fast, or locked; i.e. the balance must he relieved from any weight, so as to
avoid the speedy destruction of the knife-edges by sudden movements, jerks or
thrusts. After the crane or winch has completed its stroke, the knife-edges ar
released and replaced upon their supports or "plates," and the balance, being thus
once more in readiness for weighing, may now record its readings.
This method of weighing with the suspended load at rest gives faulty results
because all the rollers, sheaves or pulleys placed along the path of the rope, or chais
between the load and the weighing machine, and more particularly the head
roller of the jib of the crane, are so many causes of loss of energy through friction.
If such loss were constant independently of time, it would have no influence upon
the results of the weighing operations, provided the graduations of the scale were
arranged accordingly. But then the coefficient of friction is dependent upon
lubrication, being, in fact, variable within wide limits as regards the friction

page_text: occurring during periods of rest, and less extensively variable as regards the friction
of motion. Hence the errors in the indications are very serious, if these be taken
while the weighing mechanism is at rest.
The results of the weighing are furthermore influenced by the length of the rope
o1 chain suspended between the head of the jib and the load. Again, it should be
borne in mind that the virtual diameter of the rope or chain roller is variable,
according to how the rope or chain lies on its periphery, for example whether the
majority of the chain links lie flat, or stand upright or on edge.
For this inaccurate weighing process which is based upon the statical effect of
forces, there is, according to the present invention, substituted a method of weigh-
ing loads, which enables the dynamic effects to be utilised, and which attains a
maximum of precision in its results.
When, immediately after the starting period is over, the state of inertia is
attained, i.e. when the load has acquired its momentum, the weighing machine,
upon the hook of the winch (or equivalent attachment for the load) reaching a
predetermined height, is automatically replaced upon its knife-edges by the
winch-mechanism, and thereby enabled to perform its weighing operation; from
which position it is automatically shifted again after the lapse of a short space of
time of predetermined duration, by being relieved from the load. The results of
this "dynamic" weighing process may be summarised as follows:-
.
1. The results of the weighing are read off whilst the moving parts are in the
condition of inertia, whereby losses by friction are reduced and made uniform.
2. The reading off of the weighings takes place with the hook constantly at the
same height; and
3. Such reading off is independent of the method or arrangement adopted for
supporting the cord or chain upon the roller or drum.
This improved weighing process may be carried out in practice by means of
mechanisms of different kind, capable of answering the purpose in question, one
form of such mechanism consisting f.i. in a double-armed lever carrying on one
end a guide roller, over which the weight-supporting rope is stretched at an angle
and with its other end indirectly connected to a one-armed balancing lever carrying
an adjusting weight. Whenever this balancing lever, in consequence of the
pressure transmitted from the double-armed lever to it, oscillates about its fulcrum
or pivot the distance between its centre of gravity and the perpendicular passing
through said fulcrum is varying until the pressure of the load-supporting rope or
chain is counterbalanced, such pressure being proportionate to the weight of the
load which the rope or chain sustains.
Upon the balancing or weighing lever there may be mounted an index hand or
pointer, adapted to indicate the weight of the load; means being provided, if
preferred, for recording its markings or readings upon a paper roll or equivalent
arrangement.
The mechanism is operated automatically from the winch, a cam being driven
from the drum-shaft by any convenient gearing. The ratio of transmission how-
ever must be so determined, that during each complete movement of the load-
carrying hook, the cam performs one complete revolution. Whilst the lifting
movement is taking place, the said cam acts upon a bell-crank-lever, to one end of
which an anti-friction roller is fitted, while a cord or chain may be attached to
its other arm. Such cord or chain furthermore acts upon a roller or drum, which
is loose on the same pivot, whereon the above mentioned balancing lever is adapted
to swing. The roller or drum by any suitable means is caused to impel the anti-
friction roller to roll along the periphery of the cam driven from the drum-shaft.
The moment the antifriction roller has passed that portion of the cam, which is
other than circular, the roller or drum loose on the same pivot as the balancing
weight will begin to turn and the weighing lever, which until now has been at
rest on a tappet or stop, provided on the weight on the roller or drum, is released,
so that the weighing of the load can take place. As the antifriction roller re-enters
upon the circular portion of the cam, in the upward direction, the roller or drum

page_text: will immediately, by means of the stop, hold back the weighing lever, and thereby
once more release or throw out of gear, the weighing mechanism.
In order to prevent the weighing mechanism from being thrown into the
operative position whilst the load is being lowered, means are provided to complete
the circular rim of the cam driven by the drum-shaft, so as to prevent the contact
or antifriction roller and the bell-crank lever, of which it forms part, from perform-
ing any movement during that stage of the operation. Such means may consist
in a segment of a circle, which, during the lifting stage of the operation is retained
in the position of rest, so as to expose the non-circular portion of the cam; while,
during the lowering period, it is caused to shut off or cover over such non-circular
part, so that the path or track of the antifriction roller becomes circular.
Dated this 20th
1007
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improved Weighing Machine adapted to be used in conjunction with
a Crane or Hoist for Weighing the Loads whilst Raising them.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Gentleman, do hereby declare the nature of said invention (a communica-
tion to me from abroad by the Joint Stock Company "Eisenwerk (vormals Nagel &
Kaemp) Actien-Gesellschaft," of Uhlenhorst, near Hamburg, in the Empire of
Germany,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
Many attempts have been made to combine cranes and winches with weighing
machines designed substantially as follows:-
At a convenient point of the path of the rope or cord there has been situated a
roller pulley or drum, supported by one end of the beam of a balance, over which
roller pulley or drum the rope or chain was passed in such a manner that the
pressure exercised upon the roller pulley or drum by the bend or turn of such rope
or chain could be ascertained at the opposite end of the beam, either by means of
weights placed upon a scale, or by a weight or runner sliding along the beam
itself; or, by reading off the amount of pressure from the extent of the deflection
of the balance-beam; which deflection would take place owing to the varying
pressure of the said roller pulley or drum wherever the beam was poised in a
constant or uniform manner, by means of either a weight or spring.
Such weighing apparatus would constitute a great convenience by enabling the
crane-driver himself to weigh the loads as they were raised or lowered by the crane,
instead of necessitating a special attendant for weighing and involving a pro-
portionate loss of time. All weighing machinery of this kind has, however, proved
unsatisfactory inaccurate and unreliable generally. The reason for this fact is,
that as the load is being lifted, the knife edges of the weighing machine have to
be made fast, or locked; i.e. the balance must be relieved from any weight, so as
to avoid the speedy destruction of the knife-edges by sudden movements, jerks or
thrusts. After the crane or winch has completed its stroke, the knife-edges are
released and replaced upon their supports or 'plates"; and the balance, being
thus once more in readiness for weighing, may now record its readings.
This method of weighing with the suspended load at rest gives faulty results,
because all the rollers or pulleys placed along the path of the rope or chain between
the load and the weighing machine, and more particularly the head roller of the

page_text: But the
jib of the crane, are causes of loss of energy through friction. If such loss were
constant, independently of time, it would have no influence upon the results of the
weighing operations, provided the scale be graduated accordingly.
coefficient of friction being dependent upon lubrication, and, in fact, variable
within wide limits as regards the friction occurring during periods of rest, and less
extensively variable as regards the friction of motion, the errors in the indications
are very serious, if taken while the weighing mechanism is at rest.
The results of the weighing are furthermore influenced by the length of the rope
or chain suspended between the head of the jib and the load. Again the virtual
· diameter of the rope or chain roller is variable, according to how the rope or chain
lies on its periphery, for example whether the majority of the chain links lie flat, or
stand upright or on edge.
For this inaccurate weighing process which is based upon the statical effect of
forces, there is, according to the present invention, substituted a method of weigh-
ing loads, which enables the dynamo effects to be utilised, and which attains a
maximum of precision in its results.
When, immediately after the starting period is over, the state of inertia is at-
tained, .e. when the load has acquired its momentum, the weighing machine upon the
hook of the winch (or equivalent attachment for the load) reaching a predetermined
height, is automatically replaced upon its knife-edges by the winch mechanism,
and thereby enabled to perform its weighing operation; from which position it is
automatically shifted again after the lapse of a short space of time of predetermined
duration, by being relieved from the load. The results of this "dynamic" weigh-
ing process may be summarised as follows:-
1. The results of the weighing are read off whilst the moving parts are in the
condition of inertia, whereas losses by friction are reduced and made uniform.
2. The reading off of the weighings takes place with the hook constantly at the
same height; and
3. Such reading off is independent of the method or arrangement adopted for
supporting the cord or chain upon the roller or drum.
This improved weighing process may be carried out in practice by means of any
mechanism, capable of answering the purpose in question, one form of which is
represented by way of example in the accompanying drawing.
The weight-supporting rope stretched at an angle over the guide roller b, pivotted
to one end of a double-armed lever a, exercises pressure upon such roller. This
pressure is transmitted from the lever a to the one-armed balancing lever d through
the rod c; such lever d carrying the balancing weight e, which is adjusted and
then secured in position upon d.. Whenever the lever d turns about
the pivot, point, or fulcrum n, the distance between its centre of
gravity and the perpendicular passing through the point n is variable,
until it counterbalances the
pressure of the load-supporting rope or
chain upon the roller b, such pressure being proportionate to the weight of the
load which the rope or chain sustains. Upon the pivot of the weighing lever d
there is mounted a pointer o, adapted to indicate the weight of the load upon a fixed
graduated scale on an arc, means being provided, if preferred, for recording its
markings or readings upon a paper roll or equivalent arrangement. The position I
of the pointer corresponds to the maximum weight, and the position II to the
minimum weight; I and II° being the corresponding positions of the weighing
levard. The weights of all the swinging parts should be as accurately as possible
adjusted, the guide rollers being preferably fitted with roller-bearings, the levers
with knife-edge supports, and the shafts, spindles or pivots with point bearings.
The mechanism is operated automatically from the winch, a cam f of suitable shape
being driven from the drum-shaft by toothed or other convenient gear. The ratio
of transmission of motion through this gearing is so determined that during each
complete movement of the lead-carrying hook, the cam performs one complete
revolution. Whilst the lifting movement is taking place, the said cam acts upon
a bell-crank lever g, to one end of which an antifriction roller h is fitted, and a

page_text: cord or chain i to its other extremity; such rope or chain acting upon a roller or
drum k, after passing over suitable guide-rollers. The roller k is loose upon the
pivot whereon the balancing weight e is adapted to swing. The roller k has formed
on or fixed to it a weight, the object of which is constantly to impel the roller h to
roll along the periphery of the cam f. The moment the roller h passes that portion
of the cam f, which is other than circular, the roller k will begin to turn, and the
weighing lever d, which until now has been at rest upon a tappet or stop 7, provided
on the weight on the roller k, is released, so that the weighing of the load can take
place. As the roller h re-enters upon the circular portion of the cam f, the roller or
drum will immediately, through the medium of the stop l, arrest the weighing
lever d, and thereby again release, or throw out of gear, the weighing mechanism.
In order to prevent such weighing mechanism from being thrown into the operative
position whilst the load is being lowered, the circular rim of the cam f, may, be
completed so as to prevent the bell crank lever g from performing any movement
during that stage of the operation. For this purpose a segment m is provided,
which, during the lifting stage, is retained in the position of rest by a stop provided
on the cam roller, so as to expose the non-circular portion of the cam; while, during
the lowering period, it is, by its own weight, caused to shut off, or cover over, such
non-circular part, so that the path or track of the pressure roller becomes circular.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A weighing machine inserted in the path of the rope, cord, or chain, of a crane
winch or hoist adapted to be automatically moved into the operative position,-after
the load-lifting movement has entered upon the state of inertia-by a cam
mechanism operated from the winch crane or hoist whenever the load attains a pre-
determined height; whereupon after performance of the required weighing opera-
tion, it is after a certain short space of time, restored to its inoperative position,
substantially as set forth.
2. In a weighing machine such as referred to in the preceding claim, a cam f
actuated by the drum shaft, for the purpose of throwing the weighing lever d in
and out of gear, said cam being arranged to be converted into a complete circular
disc during the descent of the load, or return movement of the mechanism, by a
segment such as m which, during the forward stroke, is arrested, substantially as
described.