Improvements in Weighing Machines.
Year: 1890

page_text: Date of Application, 1st Oct., 1890
Complete Specification Left, 1st July, 1891-Accepted, 1st Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Weighing Machines.
I, WILLIAM SNELGROVE of The "Nest" Kings Norton in the County of
Worcester Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to that class of weighing machines in which hitherto
the weighing has been effected by moving a poise or poises along a suitably
suspended steelyard or beam, and it consists mainly in a new arrangement of
parts, whereby I dispense entirely with a sliding poise or poises, and substitute
a much simpler and more advantageous apparatus, which admits of inexpensive
construction and great accuracy in weighing. The main part of my invention
consists in a weighing apparatus attached to a steelyard or beam, which
comprises two cylinders, drums, or barrels, geared together by suitable toothed
wheels, and shafts, and spindles; so that both cylinders or drums rotate together.
Upon these cylinders, as I shall hereinafter term them, I coil a chain so arranged
that when the cylinders are rotated, the chain coils on one, and off the other; so
that one takes the chain as the other uncoils it. In this manner I cause the chain
to coil on, to fill either cylinder simultaneously with its uncoiling from the other,-
the direction in which I rotate the cylinders determining which cylinder shall coil
on the chain. The chain fulfils the purpose commonly supplied by the sliding
poise or poises, and it will be evident that as it is coiled on the drum or cylinder
furthest from the knife edges, upon which the beam or steelyard vibrates, or upon
the cylinder nearest the free end of the steelyard, weight is applied to the steel-
yard or beam tending to balance a load placed upon the weighing platform or pan.
When sufficient chain has been coiled on that cylinder, then the steelyard will
balance and weigh the goods upon the platform or pan. The weight of the load to
be weighed will be determined by the amount of chain which has been coiled off' the
inner cylinder and consequently on to the outer one, and this can be readily indicated
by pointers on dials showing the exact numbers of revolutions made by the cylinders
together with the fractional parts of a revolution. The limit of the weighing
power of a given machine is reached when the chain is coiled on the outer cylinder,
or that nearest the free end of the steelyard or beam to fill it, and thus all chain
which can be uncoiled is transferred from the inner to the outer cylinder. When
the chain is coiled on the inner cylinder to fill it then the steelyard is in equilibrium
and this is the case when no load is on the platform and the weight indicating
pointer stands at zero.
In weighing by the movement of a poise along a steelyard, it is well known that
the most accurate results would be obtained if it were practically possible to adopt
a very long steelyard with only one light poise, and accomplish the weighing
entirely by aid of the light poise. A considerable movement of the poise then
corresponds to a comparatively small weight, and the error due to the reading of
the position of the poise on the steelyard is but little. With a heavy poise a slight
inaccuracy in the adjustment of the poise may introduce error.
My cylinders with a chain passing between them allow me to obtain the
advantages of a one light poise, on a very long steelyard, without the disadvantages.
That is, the coiling movement of the chain on the cylinders is equivalent to the
movement of each link as if it were a light poise moved through the whole distance
so coiled.
In carrying my invention into effect I may use any type of chain, wire or
weighted band or cord, but I prefer to use pitch chains of the well known flat
link type.
My invention may be applied with advantage to any type of steelyard or beam

page_text: weighing machine and it may also be used for adding the weight to lever
testing machines at present adopted for making tests of tensile and other strengths
of materials.
The cylinders may be grooved to receive the chain or a guide may be adopted
to traverse by the aid of a screw and cause the chain to coil uniformly off one
cylinder, and on the other if required. The gearing adopted for actuating the
cylinders I vary in accordance with the type of weighing machine to which it is
applied, and it may be moved by hand or by mechanism.
In applying my invention to electrical weighing machines such as are described
in the Specifications of Patent No. 11251 of 1888 and Patent No. 7335 of 1887
already granted to me, I construct the following mechanism which forms another
part of this invention.
I mount upon a steelyard two cylinders one of which is usually placed at a
greater distance from the knife edges upon which the steelyard vibrates than the
other, and I connect the cylinders preferably by a way shaft and bevil wheels and
pinions. I also mount upon the steelyard an electro motor which is actuated by
an electric current passing through spring or other contacts on the free end of the
steelyard. When the load is placed upon the pan and the free end of the steel-
yard rises, contact is made with the upper part of the carrier and a current passes
and actuates the electro motor; and at the same time an electro magnetic clutch so
gears the motor spindle to the way shaft that the chain is caused to coil on the
cylinder nearest the free end of the steelyard and off the other. Immediately
sufficient weight has been applied in this manner, the steelyard falls, and breaks
the upper contact, this at once throws out the clutch gearing the motor spindle to
the cylinders, and they stop. If the slight momentum of the apparatus has caused
too much chain to be coiled on the outer cylinder, then the steelyard end falls and
makes the lower contact which passes the current to the electro motor to rotate it
in the same direction as at first but causes a second electro magnetic clutch to gear
to the motor spindle, so as to reverse the direction of revolution of the drum.
This second gearing is arranged preferably with a slow movement, so that the
return which effects the adjustment may be made at a slower rate.
If, when the steelyard end rises from the lower contact, it just balances the load',
it remains in equilibrium. The clutch is then disengaged and the current to the
electro motor ceases, so that it stops after a time. When the load is taken off the
platform the steelyard touches the lower contact, and the chain is run back by
the motor to bring the steelyard into equilibrium with the empty platform, which it
docs at the zero point again.
The cylinders may be rotated by means of clockwork actuated by springs and
wound up at intervals in which case the electric current will be arranged to operate
the clutches which connect the clockwork with the cylinders, so that the motion of
the cylinders may be reversed when required.
Dated this 30th day of September 1890.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Weighing Machines.
I, WILLIAM SNELGROVE, of The Nest, Kings Norton, in the County of
Worcester,, 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 :-
My invention relates to that class of weighing machines in which hitherto the
weighing has been effected by moving a poise or poises along a suitably suspended
steelyard or beam and it consists mainly in a new arrangement of parts whereby I
dispense entirely with a sliding poise or poises and substitute a much simpler and

page_text: more advantageous apparatus which admits of inexpensive construction and great
accuracy in weighing. The main part of my invention consists in a weighing
apparatus attached to a steelyard or beam which comprises two cylinders, drums or
barrels geared together by suitable toothed wheels and shafts and spindles so that
both cylinders or drums rotate together. Upon those cylinders, as I shall herein-
after term them, I coil a chain so arranged that when the cylinders are rotated the
chain coils on one and off the other so that one takes the chain as the other uncoils
it. In this manner cause the chain to coil on to fill either cylinder simultaneously
with its uncoiling from the other, the direction in which I rotate the cylinders
determining which cylinder shall coil on the chain. The chain fulfils the purpose
commonly supplied by the sliding poise or poises and it will be evident that as it is
coiled on the drum or cylinder furthest from the knife edges upon which the beam
or steelyard vibrates or upon the cylinder nearest the free end of the steelyard,
weight is applied to the steelyard or beam tending to balance a load placed upon
the weighing platform or pan. When sufficient chain has been coiled on that
cylinder then the steelyard will balance and weigh the goods upon the platform or
pan. The weight of the load to be weighed will be determined by the amount of
chain which has been coiled off the inner cylinder and consequently on to the outer
one and this can be readily indicated by pointers on dials showing the exact numbers
of revolutions made by the cylinders together with the fractional parts of a
revolution. The limit of the weighing power of a given machine is reached when
the chain is coiled on the outer cylinder or that nearest the free end of the steel-
yard or beam to fill it and thus all chain which can be uncoiled is transferred from
the inner to the outer cylinder. When the chain is coiled on the inner cylinder to
fill it then the steelyard is in equilibrium and this is the case when no load is on
the platform and the weight indicating pointer stands at zero.
In weighing by the movement of a poise along a steelyard it is well known that
the most accurate results would be obtained if it were practically possible to adopt
a very long steelyard with only one light poise and accomplish the weighing entirely
by aid of the light poise. A considerable movement of the poise then corresponds
to a comparatively small weight and the error due to the reading of the position of
the poise on the steelyard is but little. With a heavy poise a slight inaccuracy in
the adjustment of the poise may introduce error.
My cylinders with a chain passing between them allow me to obtain the advantages
of a one light poise on a very long steelyard without the disadvantages. That is
the coiling movement of the chain on the cylinders is equivalent to the move-
ment of each link as if it were a light poise moved through the whole distance so
coiled.
In carrying my invention into effect I may use any type of chain, wire or
weighted band or cord but I prefer to use pitch chains of the well known flat link
type.
My invention may be applied with advantage to any type of steelyard or beam
weighing machine and it may also be used for adding the weight to lever testing
machines at present adopted for making tests of tensile and other strengths of
materials.
The cylinders may be grooved to receive the chain or a guide may be adopted
to traverse by the aid of a screw and cause the chain to coil uniformly off one
cylinder and on the other if required. The gearing adopted for actuating the
cylinders I vary in accordance with the type of weighing machine to which it is
applied and it may be moved by hand or by mechanism.
Referring to the accompanying sheet of drawings in which my invention is shown
as applied to electrical weighing machines such as are described in the
Specifications of Patents No. 11251 of 1888 and No. 7335 of 1887 already granted
to me,
Figure 1 is a side elevation showing part of the steelyard with the novel
arrangements.
Figure 2 is a plan of Figure 1,

page_text: Figure 3a transverse section on the line < y and
Figure 4 a separate plan of the two cylinders.
I mount upon a steelyard two cylinders B, C one of which is placed at a greater
distance from the knife edges A upon which the steelyard A vibrates than the
other, and I connect the cylinder sometimes by a way shaft and bevil or spur
wheels and pinions: I also mount upon the steelyard an electro motor E? which is
actuated by an electric current passing through spring or other contacts on the free
end of the steelyard as described in my previous Patents already referred to.
When the load is placed upon the pan and the free end of the steelyard rises,
contact is made with the upper part of the carrier and a current passes and actuates
the electro motor E'; and at the same time an electro magnetic clutch so gears
the motor spindle to the way shaft or toothed wheels that the chain is caused to
coil on the cylinder B nearest the free end of the steelyard and off the other C
nearest the knife edges A'. Immediately sufficient weight has been applied in this
manner the steelyard A falls and breaks the upper contact this at once throws out
the clutch gearing the motor spindle to the cylinders and they stop. If the slight
momentum of the apparatus has caused too much chain to be coiled on the outer
cylinder then the steelyard end falls and makes the lower contact which passes the
current to the electro motor to rotate it in the same direction as at first but causes
a second electro magnetic clutch to gear to the motor spindle so as to reverse the
direction of revolution of the drum. This second gearing is arranged preferably
with a slow movement so that the return which effects the adjustment may be made
at a slower rate.
If when the steelyard end rises from the lower contact it just balances the load
it remains in equilibrium. The clutch is then disengaged and the current to the
electro motor ceases so that it stops after a time.
When the load is taken off the
platform the steelyard touches the lower contact and the chain is run back by
the motor to bring the steelyard into equilibrium with the empty platform which it
does at the zero point again.
In the arrangement shown upon the drawings, the electro motor, E', always
rotates, when receiving current, in the direction of the arrow marked 1 upon I,
and the pinion Es upon its spindle rotates the train of wheels E, E, E³, always
in one direction, that of the arrow 1 upon their peripheries (see Figure 1). The
spindle H is always rotated in one direction also that of the arrow 1 on the
wheel, E. But H carries two clutch pinions E3 and E8 with clutch surfaces G², F2
which move with them and may engage with the fixed clutch pieces G³, F3. When
the free end of the steelyard A rises by the effect of a load on the platform the
contacts so direct the current that the pinion E³ is driven by the clutch piece G³
fixed on the spindle H. The electro magnet G accomplishes this by action on the
clutch lever G and sliding the clutch surface G2 so as to gear with the teeth of G³.
The motion of H is then communicated to the cylinders B, C through the
wheels E, E by the spindle K to E which engages toothed wheels B¹, C¹ and so
rotates the cylinders in the direction of the arrows 1 and coils chain off C and on B
which is equivalent to sliding out the poise. When the steelyard A: overbalances
and leaves the upper contact the current ceases to excite the electro magnet G and
the clutches G2, G³ disengage, the armature lever G' being pulled off by a spring.
The pinion E is then loose on the spindle H. If the steelyard falls to the lower
contact then the current excites the electro magnet F and by the armature lever F
the clutch pinion E is moved to engage its clutch surface F2 with the clutch F³
fixed on the spindle H. E then drives the large toothed wheel E direct and
rotates the cylinders B, C in the direction of the arrows marked 2 to wind chain
back from B to C. This motion is slower, however, as E8 gears direct into E. and
the intermediate wheel E is dispensed with. The chain is thus slowly coiled. off
till the steelyard rises and balances when the clutch is at once withdrawn.
The electro motor is supplied with current from any convenient source by the
wires a band the electro magnet F is supplied by wires cd; and G by wires not
indicated.

page_text: The chain is indicated in Figure 1 at D and Figure 4 shows a plan of the two
cylinders showing the chain coiled on C and ready to be coiled on B. The
two cylinders B, C may be applied to any weighing machine instead of a sliding
poise.
The cylinders may be rotated by means of clockwork actuated by springs and
wound up at intervals in which case the electric current will be arranged to operate
the clutches which connect the clockwork with the cylinders so that the motion of
the cylinders may be reversed when required.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is : :-
(1.) In steelyard or beam weighing machines the use of a chain or its equivalent
coiled on one cylinder from another geared to it, the said arrangement dispensing
with the usual sliding poise substantially as and for the purposes hereinbefore
described and illustrated.
(2.) In an electrically controlled weighing machine the use of a chain or its
equivalent coiled on one cylinder from another geared to it, the electrical contacts
and electro magnets and clutches being so arranged that when the free end of the
steelyard rises chain is coiled so as to act as a poise and weigh the load; the over-
balancing of the load causing the direction of rotation of the cylinders to be
reversed and the chain to be coiled back till balance and an accurate weighing is
obtained substantially as hereinbefore described and illustrated.
(3.) The electrical weighing machine hereinbefore described and illustrated in
Figures 1, 2, and 3 of the drawings.
Dated this 30th day of June 1891.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.