Year: 1887

page_text: Date of Application, 19th May, 1887
Complete Left, 19th Mar., 1888
Complete Accepted, 19th May, 1888
I, WILLIAM SNELGROVE, of 42, Hillsboro' Road, North Dulwich, in the County of
Surrey, Engineer, do hereby declare the nature of this Invention, to be as follows :-
According to my invention I construct lever, or compound lever balance, weigh
beam or steel-yard weighing machines which shall be self adjusting and self
indicating, and I also use in combination therewith, if required or desired, printing or
recording mechanism for printing on tickets or their equivalents the correct weights
as found by the said weighing machines.
In carrying out my invention 1 employ a balance, weigh beam or steel-yard
suspended on knife edges and having a free end vibrating between the jaws of the
loop guide or carrier. The sliding weight or poise, I construct with grooved wheels
or equivalent mechanism to enable it to travel freely from one end of the steel-yard to
the other. The poise is provided with two independent pinions gearing into a rack
extending from end to end of the steel-yard. These two pinions are separately
connected by suitable mechanism to the driving shafts of two distinct small electro-
magnetic engines or electro-motors which are arranged to run in opposite directions
and are attached to (or in fact form part of) the said sliding poise. Or I may by
varying the arrangement of pinions and other parts use only one but reversible
electro-motor. On the upper and under sides of the steel-yard and extending about
from end to end, but insulated therefrom are two metal rods forming electrical
conductors. Each electro-motor on the sliding poise is in sliding contact with one of
the said rods. The motor, which when in motion will cause the pinion to traverse the
rack in a direction towards the free end of the steel-yard, is in sliding contact with
the upper rod; while the motor, which will revolve the pinion in an opposite
direction, viz. toward the pivotted end of the steel-yard, is in contact with the lower
rod. At the upper and lower sides of the carrier between which the free end of the
steel-yard vibrates are attached electrical contact points which are in connection
with one of the poles of a galvanic battery, the other pole being connected to the
other end of the steel-yard and the circuit is completed by the rise or fall of the steel-
yard bringing one or other of its conducting rods aforesaid into contact with the said

page_text: points, the electric current passing from the contact point on the carrier, along the
conducting rod, through one or other of the electro-motors, and thence, by way of the
pivotted end of the steel-yard, back to the opposite pole of the battery. The electro-
motors are so arranged that a current passing through one of them from the upper
contact point of the carrier causes the motor to revolve the pinion on the poise to
which it is connected and causes the said pinion to travel on the rack of the steel-
yard, carrying with it the poise in a direction towards the free end of the steel-yard,
while on the other hand a current received from the lower contact point of the carrier
causes the other motor and its pinion to revolve in the opposite direction and the poise
to travel towards the pivotted end of the steel-yard.
On the weight being placed on the scale pan or platform the free end of the steel-
yard rises and comes into contact with the upper contact point of the carrier, as
above mentioned; the electro-motive poise at once commences to travel along the
rack of the steel-yard until it counterbalances (in the same way as if moved by hand)
the weight on the platform. The moment this takes place the free end of the steel-
yard leaves contact with the carrier and breaks the current, and the poise stops at the
balancing point. The weight indicated can then be read off, in the usual manner, by
divisions on some part of the steel-yard, and also by pointer and dial, as hereinafter
described. On the weighed goods being removed from the platform the free end of
the steel-yard naturally falls into contact with the lower contact point of the carrier,
the current then passing into the other electro-motor and the poise travelling back
toward the pivotted end of the steelyard.
To prevent the poise over running at either extremity of the steel-yard I provide
for the automatic breaking of the current between the electro-motors and the con-
ducting rods on the steel-yard at the required points. If therefore (from the goods
on the platform being beyond the scope of the machine and too heavy for the poise to
balance) the poise should run right out to the free end of the steel-yard, the motor will,
on coming to the contact breaking place, run off connection with the upper conducting
end and therefore stop, while when the goods are removed the extended lower conductor
will duly connect with the return motor and cause the poise to return to zero or until
in fact it again runs off contact, this time from the lower conductor at the zero end
of the steel-yard.
It will be noted that both motors are never out of contact with both conducting rods
at the same time but are so individually only in any case when from the position of
the poise their individual movement would be useless or even impossible.
In order to render the weight indications in my machine more easily read 1
construct one or more dials and suitable pointer or pointers and I cause the traverse
of the poise on the steel-yard to revolve the dial or dials, or pointer or pointers by
means of a chain or cord attached to the poise and actuating pulleys, or a rack and
pinion, or other suitable arrangement; or, if the dials, etc. are attached to the poise
itself, the driving pinion on the poise may be made to actuate the pointers or dials.
As the movement for actuating the indicators is obtained by electric current and is,
contrary to the usual self indicating machines, entirely free from and independent of
the weight of the goods on the platform it will be obvious that I can employ the
most suitable mechanical contrivances known, practically regardless of the amount of
friction entailed by their use, whereas in the ordinary self indicating weighing
machines the indicating devices even when of the crudest and simplest kind materially
prejudice the sensitiveness or accuracy of the weighing balance. Furthermore by my
invention I obtain the admittedly vast advantages of the self indicating weighing
machines in combination with the unfailing accuracy of the steel-yard and compound
knife edge supported lever system.
It will be obvious that many descriptions of printing or recording mechanisins.
which have been or can be applied to ordinary steel-yard lever machines can be
equally applied to my self indicating and self adjusting machine. In my invention
moreover as the poise automatically adjusts itself (and consequently the printing
mechanism) to the absolutely correct weight, the numerous errors arising from the
carelessness or incompetence of the weigher are entirely prevented.

page_text: In the cases where I attach printing mechanism to my invention I prefer, however,
to construct a claw or stop in conjunction with the printing lever kept out of gear
normally by a weight or spring but which is drawn into stopping contact with the
said lever by an electro-magnet, the said magnet acting on the completion of an
electric circuit which is effected by the contact of the free end of the steel-yard with
either the upper or lower side of the carrier support. By this arrangement I prevent
the weigher printing a ticket unless the steel-yard or balance is in equipoise and the
weight printed must therefore be correct.

page_text: I, WILLIAM SNELGROVE of 42 Hillsboro' Road North Dulwich in the County of
Surrey Engineer do hereby declare the nature of the said invention and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
According to my invention I construct lever or compound lever balance weigh beam
or steelyard weighing machines the sliding poise of which in the operation of weighing
shall by electrical power be self-adjusting or automatically assume the correct position
on the steelyard or beam and may also be self-indicating and I may also use in com-
bination therewith if required or desired printing or recording mechanism for printing
on tickets or their equivalents the correct weight as found by the said weighing
machines.
By this application of electricity to move a sliding weight or poise in balance scale
beams steelyards or weighing machines the weighing of goods will be effected auto-
matically and all liability of error in weighing (intentional or otherwise) will be
reduced to a minimum.
In carrying out my invention I employ a balance, weigh beam, or steelyard
suspended on knife edges and having a free end vibrating in a loop guide or carrier,
the steelyard carrying a sliding weight or poise which by means of an electro motor
is caused to start automatically from zero when the goods are placed on the platform
or scale pan; stop automatically when equilibrium is obtained and return automatically
to zero when the goods are removed.
Figure 1 of the accompanying drawings is a side elevation of a steel yard having
my invention applied thereto, Figure 2 is a plan and Figure 3 a vertical cross section
of same.
The steelyard A is suspended on knife edges O and its free end vibrates between
electrical contact points J¹ and J in the upper and lower part of the loop guide or
carrier.
The sliding weight or poise may consist of a trolly B with grooved or flanged
wheels W or equivalent mechanism to enable it to travel freely from one end of the
steelyard A to the other.
The poise is provided with a pinion P which is so mounted that it can gear either
with a lower rack Q or with an upper rack Q₁ both extending along one side of the
steelyard A as will be presently explained.
The pinion P is by tooth wheel gearing connected to the driving shaft or spindle T
of a small electro motor C carried by the sliding poise and arranged in connection

page_text: with suitable reversing gear to reverse the motion of the sliding poise causing it to
run either in or out on the steelyard.
On the upper side of the steelyard A and extending from end to end but insulated
therefrom are two metal rods L and L' forming electrical conductors.
The electro motor C on the sliding poise is by means of the contact spring M or
the contact spring M³ in sliding contact with the conductor L or the conductor L'
respectively. When the poise is near the fulcrum O of the steelyard or in its normal
position of rest the contact M will be upon the insulated piece N and to this position
of rest the poise is always returned when not weighing.
The motor C when in electrical connection with the conductor L will drive the
propelling pinion P and cause it to traverse or roll on the lower rack Q in a direction
towards the free end of the steelyard. Conversely when the motor is in electrical
connection with the insulated conductor L' the pinion P is caused to roll on the upper
rack bringing the sliding poise back to the fulcrum O.
At the upper and lower sides of the carrier between which the free end of the
steelyard vibrates are attached the electrical contact points J and J which are in
connection with one of the poles of a galvanic battery (which may conveniently be
arranged in the hollow supporting pillar) the other pole being connected to the
fulcrum pin O at the other end of the steelyard. The circuit is completed by the rise
and fall of the steelyard bringing one or other of the conductors L or L' into electrical
connection with the contact points J or J¹ the electric current passing from the contact
point on the carrier along the conductor L or L' through the electro motor and by
way of the fulcrum O of the steelyard back to the opposite pole of the battery.
Or the two poles may be connected with the same end of the steelyard corresponding
double contact pieces being arranged in the loop so that the current will pass by the
bar L' and vice versa in a manner well understood by electricians.
The motor C is mounted on a spindle T which by means of tooth-wheel gear C₁
CCCC¹³ is connected to the propelling pinion P. The wheel C is in one with the
pinion P which latter as already stated can roll or travel on the upper rack Q¹ or
the lower rack Q. The gudgeon P¹ for the pinion P is fixed in the end of a lever
or arm R keyed on the central boss of the yoke D. This latter and the lever R
vibrate on the pin F which is fixed to the side of the carriage and serves also as the
stud axle for the wheels C and C which are formed in one piece.
H is a brake for stopping the motion of the motor by pressure against the disc I on
the motor shaft T. This brake is kept on by means of a spring H¹ the upper stem
of the brake H being held in a cross bar H. The yoke D is fitted with soft iron
armatures S and S for the electromagnets E and E. These latter serve for reversing
the motion of the sliding poise. The projecting horns on the yoke D carry pins G
and G which take under the cross bar H³ of the brake and serve to raise the latter to
allow the motor to rotate when required.
The steelyard in its normal condition, that is to say without any weight in the
scale pan or platform will have its lower contact K clear of the carrier contact J or
midway between the contacts J and J1 and the battery circuit will be open. The
sliding poise will be near the fulcrum O and the contact M will be upon the insulated
piece N adjoining the fulcrum. To this position the sliding poise will return after
each weighing.
. On the load to be weighed being placed upon the platform the free or outer end of
the steelyard rises and the contact K¹ comes in contact with the upper contact
point J of the carrier thereby causing the current to pass along the insulated con-
ductor L through the sliding contact M and through the electromagnet E¹ and then
through the motor C and thence through the fulcrum and body of the steelyard A
back to the battery. The armature S₁ will thus be attracted bringing down the
pinion P into gear with the lower rack Q. At the same time the pin G in the yoke D
will raise the brake H thus allowing the motor to rotate. As it is here supposed to
rotate in the direction of the arrow the pinion P will roll along the rack Q and there-
with the whole poise will travel away from the fulcrum O of the steelyard until it

page_text: counterbalances (in the same way as if moved by hand) the weight on the platform.
The moment this takes place the contact K¹ on the free end of the steelyard leaves the
contact J whereby the circuit will be broken and the brake H will be immediately
depressed by its spring H' thus stopping the motor C. Should the poise go beyond
the balancing point the bottom contact K on the steelyard will come in contact with
the contact J whereby the circuit will be closed. The current then passes along the
conductor L' through the contact M¹ and from thence to the electromagnet E which
will attract its armature S on the yoke D raise the brake H and allow the motor C
again to rotate, but the opposite end of the yoke being simultaneously raised will lift
the pinion P out of gear with the bottom rack Q and into gear with the upper rack Q
The pinion P will therefore roll the poise along back towards the fulcrum until it
reaches the point of equilibrium where the poise just balances the load to be weighed,
the circuit being again broken and the motor stopped by the brake H.
The weight indicated can be read off in the usual manner by divisions on some
convenient part of the steelyard. On the weighed goods being removed from the
platform the contact K on the free end of the steelyard naturally falls into contact
with the lower contact point J the current passing into the electromagnet E so as to
raise the brake H and raise the propelling pinion P into gear with the upper rack Q
whereby the poise will be rolled back to the position of rest at the fulcrum end.
To prevent the poise overrunning at either end of the steelyard I provide for the
automatic braking of the current between the electro motor and the conductors L L'
by means of the insulating piece N at the fulcrum end while the poise will be stopped
by the carrier or contact J at the other end.
Instead of the described motor arrangement viz.: one motor with current reversing
arrangement I may if desired use a reversible motor or I might use two motors. I
would then employ two independent travelling or propelling pinions instead of the
one pinion P. These pinions would each gear into a tooth rack on the steelyard and
be connected by suitable mechanism to the driving shafts of the two distinct small
electromotors which could be arranged to run in opposite directions (or in the same
direction all according to the relative positions of the propelling pinions and racks)
and be attached to or in fact form part of the sliding poise. The insulated conductors
might run along the upper and undersides of the steelyard but insulated therefrom,
and each motor be in sliding contact with one of the conductors. By the rise or drop
of the steelyard the upper or lower conductor would come in contact with the carrier
contacts Jor J, thus closing the circuit with one or other motor by way of the
fulcrum O back to the opposite pole of the battery. One or other propelling pinion
would thus be set in motion by its respective motor and cause the poise to travel away
from or towards the fulcrum O as the case may be. The action would otherwise be
the same as above described with reference to the arrangement illustrated.
In Figure 4 I have shewn in perspective a steelyard weighing machine with a
sliding poise arranged to be automatically actuated by one of two motors placed at the
fulcrum end of the steelyard A. The sliding weight or poise B forms the nut for the
screw on the end of which is fixed a tooth wheel P. The latter is rotated in one
direction or the other by the pinions C₁or fixed on the driving spindles of the
motors C and (* respectively. The weight B is formed with a V groove and slides
on the correspondingly formed steelyard A and is thus kept from turning. L and M
are two insulated cups containing mercury arranged at the free end of the steelyard
and connected by wires to the one pole of each motor. L' and M¹ are annular
mercury cups carried by the loop guide or carrier and connected by wires to the
other pole of each motor. The circuit is completed by points or contact pieces carried
by the beam or steelyard and loop guide or carrier respectively entering or dipping
into the mercury in the cups as the steelyard rises or falls.
HH are lever brakes acting on discs I on the shafts of the motors C C* for
stopping their rotation the lower ends of the brake levers below the fulcrum forming
armatures for electromagnets E. The upper end of the brake levers are connected
together by a coiled spring the office of which is to maintain the brakes always

page_text: on until they are pulled off by the magnets E attracting the armatures.
battery N may conveniently be placed in the foot of the hollow standard Y.
The
The electric conductors although shown as wires to illustrate the action would
in actual practice be thin metallic rods arranged as snugly as possible out of sight
say under the steelyard and inside the hollow standard.
Figure 5 shows a similar kind of weighing machine with one motor C the shaft
of which is fitted with some suitable or well known reversible or double com-
mutator (not shown) such commutator being reversed by electromagnets when the
contacts J and K or J and K close circuit with the electromagnets in question.
On the motor spindle I is fixed a pinion P which directly or by intermediate tooth
wheels gears with a rack Q connected with the weight B which slides on the steel-
yard A. Z represents a weight indicating mechanism of any suitable kind which
may be placed at the fulcrum end of the steelyard such mechanism being driven
directly or indirectly from the motor shaft I or in any other convenient manner.
In Figure 6 I have shown another arrangement of steelyard with one motor C for
working the sliding weight or poise and which will also be provided with electro-
magnetic reversing mechanism for changing its direction of motion. The motor
shaft (or a spindle driven thereby) in this case is formed as a screw spindle Q which
passes through the threaded sliding weight B and propels the latter in one direction
or the other according to the direction of rotation of the motor as determined by
the circuit established by the contacts at the free end of the steelyard as already
explained.
Figure 7 shows an arrangement of steelyard in which the motor mounted at the
fulcrum end of the steelyard and made reversible in the manner described by pinion P
and wheel C (with intermediate wheel gearing when required) imparts motion to a
pulley D which by the endless band or cord Q which passes round the pulley D and
round a pulley D at the outer end of the steelyard imparts motion to the sliding
weight B this latter being attached to the endless band QI would here remark that
I do not intend to confine myself to placing the contact pieces at the free end of the
steelyard as they may be applied at the fulcrum end or in any other convenient part
of the machine.
Figure 8 shows my invention applied to an equal armed balance-The beam A is
supported on a pillar B in the usual manner and its ends work in loops or guides
carried by brackets B¹ extending from the pillar and fitted with contact pieces in
connection with the battery or other source of electricity. The beam carries a screw C
on which the weight or poise E is mounted the said screw being moved by means of
a motor D as before described. The sliding weight may be provided with a pointer
which will indicate the weight on a scale F or in any other convenient manner. In
this arrangement the goods will be placed in one scale pan and the approximate
weight in the other the difference being made up by the sliding weight or poise-The
making and breaking contact may be effected by the oscillation between two contact
pieces of a pointer carried by the beam.
In any of the above described cases the machine may be enclosed in a suitable box
to protect it against the weather and dust and wilful damage parts being left open or
glazed as required as shown in Figure 9. The printing or recording mechanism
which I may use with my electric weighing apparatus may be of any of the well
known types but as this constitutes no essential part of my invention I have considered
it unnecessary to describe such mechanism. A similar remark will apply to the weight
indicating mechanism referred to above.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
First: An apparatus for weighing in which the movement of a travelling or
sliding weight or poise is effected by means of electro motive power which is
automatically brought into play when the goods to be weighed are placed on the
platform or scale pan as described.

page_text: ==
Second An electric apparatus for weighing in which the vibration or oscillation
of the weighing beam or steelyard in the act of weighing causes the making or
breaking of an electric circuit whereby a current of electricity is conveyed to or cut
off from an electric motor in combination with a reversing appliance as and for the
purpose set forth.
Third-The combination with a scale beam or steelyard of an electro motor or
motors for automatically moving the poise as and for the purpose set forth.
Fourth-The constructions of electric apparatus for weighing substantially as
described with reference to the accompanying drawings.
1 L: 10l of March 1000
WILLIAM
SNELGROVE.
By Jensen & Son,
77, Chancery Lane, London, W.C.,
Patent Agents.
A clerical error in the original Specification having been amended by the
Patentee with the consent of the Comptroller, the printed Specification will now read
as shown below :-