IMPROVEMENTS IN WEIGHING MACHINES OR APPARATUS
Year: 1881

page_text: LETTERS PATENT to Thomas Henry Ward, of the Firm of Howl, Ward, and
Howl, of Tipton, in the County of Stafford, Engineers, for an Invention of
"IMPROVEMENTS IN WEIGHING MACHINES OR APPARATUS."
PROVISIONAL SPECIFICATION left by the said Thomas Henry Ward at
the Office of the Commissioners of Patents on the 17th August 1881.
THOMAS HENRY WARD, of the Firm of Howl, Ward, and Howl, of Tipton, in
the County of Stafford, Engineers. "IMPROVEMENTS IN WEIGHING MACHINES OR
APPARATUS."
"
My Invention relates to that class of apparatus known as platform weighing
machines," more particularly suitable for weighing loads on railway or tramway
trucks; and it has reference to improvements upon the platform weighing machine
described in the Specification to former Letters Patent granted to me, dated the
6th November 1876, No. 4294, in which the weight of a load is ascertained by
measuring the deflection from its normal path upon the principle of the paral-
lelogram organ of forces, the object of my present Invention being to produce an
apparatus of more economical construction without impairing its efficiency, and
detracting from the mathematical precision of its indications.
In carrying out my Invention two rails corresponding to the two rails on which
the truck runs are carried upon girders rocking on knife edges, which are fixed
to, say, three, or any other suitable number of struts, tumblers, or rockers, the latter
having a motion perfectly parallel to each other, rock or deflect on lower knife
edges constituting fulcra, which form the base or foundation plates of the machine.
In order to insure perfect parallel motion the fulcra are rigidly secured together,
whilst the rocking girders above fix the top knife edges.
To any one of these rockers is attached a horizontal lever, the outer end of
which bears upon a plunger which is let into a shallow hydraulic cylinder.
In order to make the hydraulic joint and to allow the plunger free play at the
same time, and yet avoid the friction due to ordinary hydraulic leather packing,
I interpose a diaphragm of india-rubber, or even a corrugated metallic diaphragm,
between the plunger and the water fixing it to the cylinder water-tight.
TDi Q71

page_text: The. water in this cylinder is conveyed into the office through a small pipe
(underneath the floor for convenience) terminating in an inverted syphon of
mercury, so that any pressure of water is communicated to the mercury and forced
up the far leg. (Up to the present point the apparatus is in duplicate, that is to
say, there is one complete apparatus for cach rail, the two being independent of
each other.)
The far legs of each of these mercurial syphons are connected together by means
of a breeches pipe discharging itself into one glass tube common to these two
syphons, which is carried up the wall through the floor, and extends up to the
ceiling of the office. This tube is graduated, say, from floor to ceiling, and contains
a column of water which will shew by its rise and fall (as actuated by the two
mercurial syphons) the resultant load of the two sides of the truck, so that the
machine is automatic; a thumb screw plug is inserted in the breeches pipe, so that
any leakage, or evaporation, or expansion and contraction of the water or mercury
can be adjusted to the graduations from time to time.
The knife-edges are so wide and each machine is so short in height that there is
no tendency to tip them over when the load comes on, hence there is no necessity
for tieing the machine down or together at all.
In order to ensure that the wagons shall be drawn on to the machine with as
little jerk as possible, the outer fulcra plates are cast with an elevated portion or
rail the exact height of the track, with suitable clearance, the back of such elevated
portion serving as a chair upon which to rest the ends of the rails which approach
the same, whereby the tendency to springing is greatly diminished.
In order to prevent the sudden flow of the water as the load comes on the
machine, which would have a tendency of forcing the mercury over the breeches
pipe, the water in the cylinder has communication with a pipe only through a
very small pin drill hole, so that whatever the load may be the rise and fall of the
water is retarded, hence it is steady in its action.
"
It will be understood that the ordinary platform is dispensed with.
The measuring apparatns may be modified by the employment of rack and
pinion gear, and a spring may be used as a resistance to each apparatus, as in the
weighing machine described in the Specification to former Letters Patent granted
to me, dated the 4th October 1877, No. 3700, in which case for convenience the
two pinions, that is to say, the one on each apparatus, are fixed on one shaft, which
extends into the office, and at that part is provided with a barrel or disc on which
the loads are graduated. In this arrangement a separate recoil gear should be used
in order to avoid all jerks, such, for instance, as a hydraulic cylinder communi-
cating with another through a small pin hole when the pressure on the lever is
brought to bear on the plunger.
The measuring gear may also be otherwise modified whilst retaining the general
construction of the machine hereinbefore described.
The measuring gear may be in duplicate in one or more offices.
The machine itself may also be modified by the employment of a platform
supported on four rockers, one at each corner, one pair being fixed on a shaft
common to the two rockers, the torsion of which shaft is resisted through a lever
connected to a Salter's spring balance, or to other levers for indicating the
weight.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Henry Ward in the Great Seal Patent Office on the 17th
February 1882.
THOMAS HENRY WARD, of the Firm of Howl, Ward, and Howl, of Tipton, in
the County of Stafford, Engineer. "IMPROVEMENTS IN WEIGHING MACHINES OR
APPARATUS."
My Invention relates to that class of apparatus known as "platform weighing
machines," more particularly suitable for weighing loads on railway or tramway
trucks, and it has reference to improvements upon the platform weighing machine
described in the Specification to former Letters Patent granted to me, dated the
Sixth November, One thousand eight hundred and seventy six, No. 4204, in
which the weight of a load is ascertained by measuring the deflection from its
normal path of struts, tumblers, or rockers upon the principle of the parallelogram
of forces, the object of my present Invention being to produce an apparatus of more
economical construction without impairing its efficiency and detracting from the
mathematical precision of its indications.
In carrying out my Invention two rails, corresponding and forming a continuation
of the rails on which the truck runs, are carried upon girders and rock upon knife
edges, which are fixed to, say, two, three, or any other suitable number of struts,
tumblers, or rockers, the latter having a motion perfectly parallel to each other,
rock or deflect on lower knife edges constituting fulcra, which form the base or
foundation plate or plates of the machine. In order to ensure perfect parallel
motion, the fulera are rigidly secured together, whilst the rocking girders above
fix the top knife edges. To any one of these rockers is attached a horizontal lever,
the outer end of which bears upon a plunger which is let into a shallow cylinder
containing liquid. In order to make a liquid tight joint and to allow the plunger
free play at the same time, and yet avoid the friction due to ordinary hydraulic
leather packing, I interpose a diaphragm of leather or india rubber, or a corrugated
metallic diaphragm between the plunger and the liquid, fixing it to the cylinder
water tight. The liquid in this cylinder is conveyed into the office through a
small pipe (underneath the floor for convenience), which may terminate in an
inverted syphon of mercury, so that any pressure of water is communicated to the
mercury and forced op the far leg. (Up to the present point the apparatus is in
duplicate, that is to say, there is one complete apparatus for each rail, the two
being independent of each other.) The far legs of each of these mercurial syphons
are connected together by means of a breeches pipe discharging itself into one
glass tube common to these two syphons, which is carried through the floor and
extends up the wall of the office. This tube is graduated, say, from floor to ceiling,
and contains a column of liquid which will shew by its rise and fall (as actuated
by the two mercurial syphons) the resultant load of the two sides of the truck,
so that the machine is automatic. A thumb screw plug is inserted in the
breeches pipe, so that any leakage or evaporation, or expansion and contraction of
the liquid or mercury can be adjusted to the graduations from time to time.
The knife-edges are so wide and each machine is so short in height that there
is no tendency to tip them over when the load comes on, hence there is no necessity
for tieing the machine down or together at all.
In order to ensure that the wagons shall be drawn on to the machine with as
little jerk as possible, an elevated portion or rail the exact height of the track is
provided, situated between and forming a continuation of the rails of the track
and of the apparatus, with suitable clearance between; the said elevated portions
may be cast in one with the outer fulcra plates, and may serve also as chairs upon.

page_text: which to rest the ends of the rails of the track, whereby the tendency to springing
is greatly prevented.
In order to prevent a sudden flow of the liquid as the load comes on the machine,
which would have a tendency to force the mercury over the breeches pipe, the
water in the cylinders has communication with the pipes only through very small
pin drill holes, so that whatever the load may be, the rise and fall of the liquid is
retarded, hence it is steady in its action It will be understood that by the fore-
going arrangements the ordinary platform extending from side to side may be
dispensed with.
The measuring apparatus may be modified by the employment of rack and
pinion gear, and a spring may be used as a resistance to each apparatus, as in the
weighing machine described in the Specification to former Letters Patent granted
to me, dated the Fourth October, One thousand eight hundred and seventy. seven,
No. 3700. The measuring gear may also be otherwise modified as hereinafter
described. The measuring gear it will be evident may be in duplicate in one or
more offices. The machine itself may also be modified by connecting the rails and
girders at each side together and supporting them on rockers, one pair being fixed
on a shaft common to the two rockers, the torsion of which shaft is resisted through
a lever connected to a Salter's spring balance, or to other levers for indicating the
weight. Similar shafts may connect the other pair or pairs of rockers.
And in order that my said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 represents in longitudinal or side elevation, and Figure 2 in transverse
section, apparatus constructed according to my said Invention. Figures 3 to 14
represent details thereof (some of which are drawn to an enlarged scale) as berein-
after described. Figures 15 to 20 represent modifications thereof, also hereinafter
described. Of the two rails of the line upon which the truck runs and with which
my weighing apparatus is combined, the one shewn in the Drawing is marked A.
I will describe the arrangement as applied to one rail of a pair of rails, it being
understood that the other rail of the pair has a precisely similar arrangement
combined therewith, as seen clearly in Figure 2. In each line and forming a
continuation thereof is a rail B carried by girders b, the said rail B being furnished
at its under part at intervals with lugs 6, through which and through the said
girders bolts b³ are passed and fastened by nuts to secure the said rails B to the
said girders b, as shewn clearly in Figures 7 and 8, which are transverse sections
taken the one on a line between two of the said bolts, and the other in a line
with one of the said bolts. The rail is provided on its underside with female knife
edges b* formed in strips let into slots in projecting parts of the said underside of
the rail. The two end knife edges each rest upon a male knife edge similarly
formed on strips c let into struts, tumblers, or rockers C furnished at their lower parts
with similar strips c² having female knife edges formed therein, and resting in the
case of the end rockers upon male knife edges formed, on similar strips d let into a
projection e from the chair E which is situated at each end of the said rail B, the
knife edge upon which the middle rocker rests being carried by a chair Eª. The
rockers C are preferably broader at their lower part than at their upper, the knife
edges c and d being similarly broader than the knife edges b and c to give a firm
base to the apparatus. In order to preserve the proper relative position of these
knife edges d, which form the base upon which the apparatus acts, their ends are
let into longitudinal braces D; Figure 9 is a section of the chairs and knife edges,
and their connecting braces; and Figure 10 is a plan of the said knife edges and
braces; Figure 11 is a transverse section drawn to an enlarged scale of one of the
chairs E with its knife edge d, shewing also the braces D in section. The normal
position of the rockers C is in accordance with the principle laid down in the
Specification of my aforesaid former Patent, videlicet, slightly inclined to the vertical
line. To the middle rocker (or it may be to one of the other rockers) is attached

page_text: or cast a lever F, the outer end of which carries a screw pin f which bears upon
the plunger g of a shallow cylinder G carried by the girders b. This plunger acts
upon a diaphragm g of leather, or india rubber, or corrugated metal or the like,
bolted water tight between the flanges of the said cylinder G and its cover, as
5 shewn clearly in Figures 3 and 7, which former Figure is a longitudinal section of
the central part of the rail B and of the lever F. This arrangement of piston and
diaphragm may be replaced by a plunger or ram sliding liquid tightly in the
cylinder G.
Pipes hand h communicate respectively with the interior of each cylinder G,
each of the said pipes terminating in an inverted syphon h³, h, containing mercury,
the other legs of the said syphons opposite those into which the said pipes h², h³,
open are connected by a breeches pipe H, so that they both communicate with one
pipe or T piece, in which is held the graduated glass tube h, which contains the
indicating liquid and is led into the place where the indications of the apparatus
are to be exhibited, as shewn in Figure 2; Figure 12 is a vertical section ;
Figure 13, a back view; and Figure 14, a plan of the pair of syphons.
The machine being in duplicate up to a certain point, any load brought on the
rail of either side will force the liquid (by preference mercury) up its independent
tube (h' or h³) independently of the other side, each side thus forming a hydrostatic
equilibrium of its own. Further, as the two pipes are afterwards connected by a
breeches pipe opening into one indicating tube, and as this breeches pipe and the
said indicating tube contain a liquid of a very much less specific gravity than that
in the duplicate parts of the apparatus, the hydrostatic equilibrium of the one side
of the machine does not interfere with that of the other side, but they both act
mutually upon the liquid of less specific gravity to give one common indication of
their combined displacement.
In the simplest form of the machine the pipes h¹, h², would communicate with
vertical pipes leading into the one common indicating tube; but in order to save
the expense of a large quantity of mercury, a cheaper fluid can intervene between
the cylinders G, and a small quantity of mercury be contained in the syphons.
This is the arrangement shewn in the Drawings. The legs of the syphons into
which the pipes h², h², open are continued upwards, as shewn in Figures 2, 13, and
14, and are each provided with a screw plug h. The breeches pipe Ĥ is also
provided with a screw plug h.
These plugs serve by adjustment to compensate for any leakage or evaporation,
or expansion and contraction of the mercury or of the liquid which fills the space
in the cylinders G, pipes h¹, h², and legs of the syphons h³, ht, into which they open
between the underside of the diagram g* and the mercury in the said syphons.
The mercury in the syphons should be at a level in each leg when no load is on the
machine.
The fulcra plates or chairs E are cast with an elevated portion e' the exact height
of the rails A and B, and forming a continuation thereof, the said chairs being also
cast with a seating at e³ for the ends of the rails.
Figures 4 and 5 are side elevations of one of the said chairs, and Figure 6 is an
end elevation of the same looking in the direction of the arrow in Figure 4,
Figure 4 shewing the end of a rail in position, and Figure 5 shewing also the end
of a rail B and girder b, and a rocker C of the weighing apparatus.
The chairs or fulcra plates of each rail of the pair of rails B, B; E, E³, are bound
transversely together by means of tie rods e', and they are fastened down to a
level bed of concrete, or stone, or the like by bolts e³.
To prevent the mercury being forced over the breeches pipe H, the liquid has
communication from each of the cylinders G to each of the pipes h³, h³, by a hole i
(shewn in Figure 7) so much smaller in capacity or sectional area than the bore of
the said pipes as to retard the flow of liquid sufficiently to prevent such overflow
of mercury.
In using the apparatus the truck or vehicle to be weighed is run from the rails A
over the elevated portion e² of the chairs E on to the rails B, the weight of the said

page_text: vehicle therefore causes a deflection of each of the rails B and their rockers C, C,
upon their knife edges, and consequently the weight brought to bear on each
rail B is respectively and independently conveyed by the pipes h¹ and h² to the
mercury in the syphons 3, 4, owing to the pressure put through the levers F upon
the pistons g of the cylinders G forcing the liquid through the hole i of each
cylinder into and along the said pipes h¹, h³, and forcing (each with an independent
pressure) the mercury down in the legs. on one side of the said syphons and up in
the other legs. The pressures are thereafter caused through the breeches pipe H
to conjoin and act upon the liquid in the tube 4º, the extent of the rise of which
will consequently give the resultant of the loads brought to bear upon both rails of
the apparatus, or in other words, the total weight of the truck or vehicle and its
contents.
The tube he may be transparent, to shew the indications, or the rise and fall of
the liquid therein may be ascertained by other suitable means.
Figure 15 represents a modification of the means for connecting the rails B to
their girders b. The rail B employed in this case is a double flanged channel rail,
which is supported at intervals by crosspieces formed by the body part of double
T pieces, as at j, bolted or rivetted, or otherwise fastened to the girders b.
Figure 16 represents in longitudinal elevation, and Figure 17 in transverse section
an apparatus similar to that herein before described, but wherein instead of the
cylinders G and pipes for conveying the pressure through syphons to the indicating
tube ho, there is employed measuring apparatus of the kind described in the
Specification of Letters Patent, No. 3700, granted to me as of the Fourth day of
October, in the year of our Lord One thousand eight hundred and seventy seven.
Each of the girders hand rails B are here shewn as being formed in one casting
mounted upon two rockers C, one at each end, the said girders and their
corresponding rockers being firmly braced and connected together by cross binding
girder bars or the like. One of the rockers of one of the girders carries the lever F,
which, acting against a spring f*, operates a segmental rack gearing with a
pinion k upon a shaft extending to the place where the indications are to be
shewn, and there carrying a graduated indicating wheel M, or being connected to
other indicating device.
The lever F is analogous to the lever F shewn in the Drawings attached to the
prior Specification of my said Patent 3700, in the year of our Lord One thousand
eight hundred and seventy seven, and the mechanism upon which it operates
is arranged and acts in a manner essentially similar to that described in the said
prior Specification, and therefore further description thereof is unnecessary. There
is combined therewith for the purpose of preventing shocks by the load suddenly
acting upon the lever F a double cylinder N, shewn separately in vertical section
in Figure 18. The compartments of this cylinder are separated by a partition n,
and through the said cylinder and partition passes a rod p, adjustable in length,
and connected at one end with the lever F and at the other end with two
diaphragms q, q, of india rubber, corrugated metal, or the like, one in each chamber
of the double cylinder N, thus liquid being in the one chamber, the lever F
can only move at a rate determined by the rapidity with which the liquid can
pass out of this chamber into the other chamber through a small hole in the
partition n.
Figure 19 represents in longitudinal elevation, and Figure 20 in end elevation
partly in transverse section another modification of the apparatus. In this case,
as in the preceding, the girders 6 and rails B of the apparatus are shewn as being
cast in one, and the two at each side, as also their chairs, are firmly connected
together. The rockers C are carried in slots in tubes, or hollow or solid shafts R
which serve as distance pieces and connectors for the corresponding rockers of
each rail B. The lever F is carried by a continuation of one of the said tubes or
shafts R, the outer end of the said lever being connected by the link or connection 8
with a Salter's spring balance S, or other weight indicating apparatus.
Although I have shewn but one pair of machines in Figures 1 to 15, yet it will

page_text: be evident that any number may be combined in a similar manner, that is to say,
each with a separate hydrostatic equilibrium, the pressure from each machine being
led to one indicator, essentially as described; for example, the machines may be
arranged in lines of pairs, and a whole train of trucks or the like be weighed by
them, and the whole weight indicated on one indicator. The machines may each be
of any length to accommodate one or more trucks or the like.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I wish it to be understood that I do not limit myself to the precise details
hereinbefore described and illustrated in the accompanying Drawings, as the same
may be varied without departing from the nature of my Invention; for example,
the separate machines at each side, as in Figures 1 and 2, might be connected by
bracing or otherwise, and one lever F and one pipe (h¹ or h³) be used for both sides,
or the double levers and pipes be retained, but this would do away with many of
the advantages resulting from the separate arrangement, what I consider to be
novel and original and therefore claim as the Invention secured to me by the
hereinbefore in part recited Letters Patent is,-
First. The combination of parts constituting the weighing machine or apparatus
herein before described and illustrated in Figures 1 to 15 of the accompanying
Drawings.
Second. In weighing machines or apparatus of the class known as platform
weighing machines, providing each rail or side of the machine or apparatus with
means for separately conveying the pressure or weight upon each to a common
indicating apparatus, substantially as herein before described and illustrated
more particularly in Figures 2, 3, 7, 12, 13, and 14 of the accompanying Drawings.
Third. In weighing machinery or apparatus of the class known as platform
weighing machines, the combination with the rail or rails, or surface or surfaces
carrying the vehicle or the like to be weighed, and the rockers C arranged as a
parallel motion of a lever or levers F formed on or connected with one or more of
the said rockers, and acting upon a column or columns of liquid, or upon mechanism,
or upon other means for indicating the weight, substantially as hereinbefore described
with reference to the accompanying Drawings.
Fourth. In weighing machines or apparatus of the class known as platform
weighing machines, the combination of two or more machines connected with one
indicating apparatus by means of tubes or passages led independently from each
machine, and afterwards led into one tube or passage in communication with the
indicator, the said independent tubes containing a dense fluid, that is, one of a high
specific gravity to form an independent hydrostatic equilibrium for each machine
with a fluid of less specific gravity above for giving the joint communication
of both or all of the machines with one common indicator, substantially as herein
before described.
Fifth. In weighing machines or apparatus of the class known as platform
weighing machines, the combined chair, illustrated more particularly in Figures 4,
5, and 6, of the accompanying Drawings, for supporting the main rails and the
rockers of the apparatus, and also affording a continuation of the track on to the
rails of the weighing machine or apparatus.
Sixth. In weighing machines or apparatus of the class known as platform
weighing machines, the combination with the hereinbefore described independent
tubes or passages communicating with the indicator of a passage which is contracted
or of less diameter or transverse sectional area than that of the said tubes or
passages, substantially as and for the purpose described with reference to the small
passage in the chamber G shewn in the accompanying Drawings.
Seventh. The combination of parts constituting the weighing machine or
apparatus, substantially as hereinbefore described and illustrated in Figures 16
and 17 of the accompanying Drawings.
Eighth The combination of norta constitutin the waichine machine A

page_text: apparatus, substantially as herein before described and illustrated in Figures 19
and 20 of the accompanying Drawings.
In witness whereof, I, the said Thomas Henry Ward, have to this my
Specificotion set my hand and seal, this Fourteenth day of February, One
thousand eight hundred and eighty two.
T, H. WARD. (L.S.)