IMPROVEMENTS IN PLATFORM WEIGHING MACHINES AND WEIGH-BRIDGES
Year: 1884

page_text: Bridges:
I WILLIAM BEILBY AVERY of 12 Digbeth, Birmingham, in the County of
Warwick, Machine Maker do hereby declare the nature of my invention for
"IMPROVEMENTS IN PLATFORM WEIGHING MACHINES AND WEIGH-BRIDGES," to be
as follows:-
The object of the present invention is to simplify the construction and reduce
the cost of making and erecting platform weighing machines, and to afford
facilities for increasing the size of the platform at any time without altering the
power of the machine or employing skilled labour.
To this end the invention consists in the distribution of the load to be borne
over a number of points, the intervals between the said points being proportioned
to the load to be carried, and in the transmission of the weight to the steelyard
connecting rod, by a novel arrangement or system of bell crank levers and
connections, or extension pieces.
The invention also relates to the use in the construction of platform weighing
machines, of wrought iron tubular members in combination with bell crank lever
castings of great strength and rigidity, carrying knife edges, and with stay or tie
rods or tubes and links or bearing stirrups for connecting the several bell cranks,
or bell cranks and tubular members, in series.
Hitherto in constructing platform weighing machines and weigh-bridges, heavy
girders and levers have been erected or enclosed within deep and costly foundations,
but my invention supersedes this system, and enables a weigh-bridge or machine
to be constructed or put together in situ upon or within shallow, easily accessible
foundations or enclosures, and permits of the size being easily extended without
disturbing the existing connections or the power of the machine.
By this invention the size of the machine can be increased by unskilled labour
by the addition of a set or sets of bell cranks with tubular members and tie rods,
and appropriate lever castings.
The platform of the machine may consist of an iron road-plate, or of planks
laid transversely upon girders or beams of suitable size and material, which are
connected and supported by underlying cross girders. These cross girders are
suspended towards their outer ends, that is towards the sides of the platform, by

page_text: link or stirrup-connections resting on knife edges carried by the bell crank lever
castings above referred to; which bell crank levers oscillate on knife edges, upon
pedestals or short standards resting on a suitable foundation, and are connected
together by stirrups or links working on knife edges and by tubular connections,
for any desired length. To transmit the synchronous oscillations of these several bell
crank levers to the connecting rod of the steel yard, special levers consisting of
bell cranks, tubular arms and stay or tie rods are employed which levers are
connected by links and centres so as to actuate another series of bell cranks
arranged transversely of and below the first described series, and connected in a
manner similar to that already described.
When the platform and cross girders are depressed, the longitudinal series of bell
crank levers will rock on their centres, and will through their connections exert a
powerful and uniform leverage upon the transversely situate system of bell cranks,
which in turn will oscillate and put a pull on the connecting rod of the steelyard
or other indicating apparatus.
The levers by which the motion of one set of bell cranks is transmitted to the
other set, and by this set to the steelyard, are, of special construction, and consist
of a tubular arm or distance tube fitting onto or into a nose or cylindrical projection
formed on a bell crank lever casting, the two parts being rigidly braced together
by tie rods passing around shoulders formed respectively on the bell crank lever
and on a nose piece or plug fitting on or into the other end of the tubular arm.
This nose piece or. plug may carry a knife edge to receive a hook or link.
The stirrups or links by which the several bell crank levers in a series may be
connected so as to synchronously and equally distribute the load on the platform
and transmit it to the steel yard, preferably consist of rectangular castings with a
threaded cylindrical tubular projection or stem at one or both ends, adapted to
screw into the correspondingly threaded ends of wrought iron tubes, or into
sockets carried thereby bearing blocks. for the knife edge on the bell crank lever
castings to work against being mounted upon a triangular block screwed to the
stirrup.
A special feature of my invention is the 'simplicity and compactness of the
arrangement, one set of bell crank levers and their connecting rods working
entirely within and between the longitudinal girders on which the platform is laid,
and the other set in the space between the cross girders and the foundation or
bed plate.
Another advantage of this arrangement is the ease with which, by removing a
plank or two, access may be had to the levers and working parts between the
main girders or beams, and any part be disconnected and removed for repairs, or be
replaced and re-adjusted.
The above system of construction effects a great saving in the cost of handling
heavy girders and levers such as are at present employed in the building of weigh-
bridges.
S

page_text: Weigh-bridges.
I, WILLIAM BEILBY AVERY of 12 Digbeth, Birmingham in the County of
Warwick, Machine Maker, do hereby declare the nature of my invention for
IMPROVEMENTS IN PLATFORM WEIGHING MACHINES AND WEIGH-BRIDGES.and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The object of the present invention is to simplify the construction and reduce
the cost of making and erecting platform weighing machines.
To this end the invention consists in the transmission of the weight to the
steelyard connecting rod by a novel arrangement of bell crank levers and con-
nections or extension pieces.
In this arrangement I use wrought iron tubular members in combination with
bell crank lever castings of great strength, lightness and rigidity carrying knife
edges, and with stay or tie rods or tubes and links or bearing stirrups for connecting
the several bell cranks, or bell cranks and tubular members, in series.
By this invention the size of the machine can be increased by the addition of
a set or sets of bell cranks with tubular members and tie rods, and appropriate
lever castings.
The nature of my improvenients will be more fully understood on reference to
the accompanying Drawing, in which
Fig. 1 is a plan view of a weigh-bridge constructed according to my invention
the top of the platform being removed to show the underlying parts, and
Fig. 2 is a longitudinal sectional elevation of the same on the line 1. 2 of Fig. 1,
the machine being represented in both of these Figures as broken through in parts
in order to reduce their length.
Fig. 3 is a transverse vertical section on the line 3. 4 of Fig. 1.
Fig. 4 represents a modification of the parts shown in Fig. 3.
Figs. 5 are detail views of a bell-crank lever and its attachments on a larger
scale.
Fig. 6 represents on a still larger scale the construction of one of the tubular
connecting rods.
Figs. 7 and 8 are detail views, on the same scale as Fig. 6, showing the 'con-
struction of the links or bearing, stirrups used with the tubular connecting rods,
and
Fig. 9 is a detail view of a link for connecting one set of levers with another set,
at right angles.
In all these Figures similar letters of reference indicate like or corresponding
parts.
A is the platform of the machine which may consist of an iron road plate, or of
planks laid transversely upon and secured to girders or beams a of suitable size
and material, the said girders or beams being connected and supported by under-
lying cross girders a'. These cross girders a' are suspended or slung towards their

page_text: outer ends, that is towards the sides of the platform A, by link or stirrup con-
nections bb, resting on knife edges c c carried by bell crank lever castings C C¹,
which bell crank levers are fitted with and oscillate on other knife edges c¹ c¹
bearing on pedestals or short standards D D, which rest on and are secured to a
suitable level foundation E forming the bottom of a shallow excavation or enclosed
space. The bell crank levers C C are connected together in series by tubular
connections or rods d and by links or stirrups e working on knife edges, to any
desired number or for any desired length, as will be seen very clearly from an
inspection of Figs. 1 and 2.
It will thus be seen that on a load being moved onto the platform A the several
levers C C¹ will rock or oscillate synchronously owing to the manner in which they
are mounted and coupled together and that the strain is distributed fairly over the
several bell cranks and their connections.
To transmit the synchronous oscillations of the bell cranks C to the connecting
rod of the steelyard, which is placed at one side, as shown in Fig. 1, so as to allow
a clear passage on to and off from the platform froin either end, I employ specially
constructed levers arranged in pairs, each lever consisting of, a bell crank C³, a
tubular arm and a stay or tie rod g, which special levers carry knife edges
oscillating on bearing blocks on or in pedestals resting on the foundation plate or
bed E as above described, and are connected by links and centres with another
series of bell cranks arranged at right angles to and below the series just described
and similarly coupled together.
The position of this second or transverse series of levers with reference to the
first or longitudinal series will be seen from Figs. 1 and 2, and' the construction
and arrangement of the said second series with respect to the girders supporting
the platform A will be now explained, reference being made more particularly to
Fig. 3.
CC² are bell crank castings fitted with knife edges or prisms c³ which work
against bearing surfaces or blocks carried by the pedestals D' D¹ which are firmly
fixed either to the foundation or bed E, or to a transverse bearing plate secured
to the longitudinal girders or beams a which support the platform. The bell
cranks C Care connected by shackles, links or stirrup connections b¹, and centres
or knife edges, to the ends of the special lever or levers, C¹ C' above described.
I preferably use the special levers in pairs as shown, to ensure smoothness of action
and equality of strain.
The bell cranks C³ C² are coupled together by tubes or rods d and links or
stirrups e in the manner described with reference to the longitudinally arranged
bell cranks C, and C¹; and any desired number of them may be used to transmit
the pull exerted by the rocking of the longitudinal series of bell cranks to the
connecting rod of a steelyard or equivalent registering apparatus at any convenient
distance from the weigh bridge.
Before proceeding to go further into details of construction it may be well to
point out that the longitudinal sets of levers and their connecting rods are each
arranged to work entirely within and between the longitudinal girders a a on
which the platform rests, and that the other set of levers works between the cross
girders a¹ a¹ in the space between the longitudinal girders and the foundation or
bed plate E thus greatly economizing the space and tending to simplicity and
compactness. Figs. 3 and 4 illustrate this point.
Referring now more particularly to the several detail views, I will explain the
construction of the various parts of the lever systems which parts may be inter-
changeable, at any rate for each system or series of levers.
The bell cranks C, C1, C2 are castings fitted with or adapted to carry knife edges
or prisms as represented. They may be formed with webbed centres as shown
at C C¹ in Figs. 1, 2, 4 and 5 for strength and lightness. Two of the knife edges
pass through and are fixed transversely in each bell crank, and the third knife
edge forms the head of a T-piece, h, the stem of which is threaded and passes

page_text: through a socket h¹ in the casting, to which it is secured by a nut as most clearly
shown in Figs. 5 6 and 7.
The connections between the several bell cranks is effected as above, stated by
tubes d, and by loops or stirrups e. The latter are fitted with threaded plugs for
attaching them to the tubes, and with a bearing block or blocks ke ke forming an
angle in which the knife edge h takes its bearing. The loops or stirrups e are
coupled to the tubes or rods by right and left handed screw threaded collars l, and
lience the connections between a pair of bell cranks can be adjusted to transmit
motion simultaneously from one bell crank to another.and thereby equally distribute
the strain,
I may employ a link working on centres as shown in Fig. 3 or a pair of links as
shown in Fig. 4, to unite the end or ends of one lever or levers with the bell
cranks of the transverse system, the latter plan being illustrated on an enlarged
scale in Figs. 5, but I preferably employ a double shackle or link working on
centres carried by the levers or moving parts which it connects, as shewn in Fig. 9
and I am thereby able to prevent lateral twisting strains on the edges of the
transversely arranged system of levers which transmit the pull to the indicating
mechanism.
In this improved form of swivelling shackle or link connection, I arrange adjust-
able screw bolts having conically recessed heads for the reception of the centres
carried by the levers, and smooth rounded surfaces at the point where the two
parts of the shackle or link touch. This form of shackle is more especially intended
to be used with bell cranks constructed and arranged as described with reference
to Fig. 3.
I will now describe more in detail the construction of the levers which transmit
the movement of one set of bell cranks to another set, reference being made more
particularly to Figs. 1, 2 and 4.
These specially constructed levers consist each of a bell crank casting such as C¹
a tubular arm or distance tube f fitting onto or into a nose or cylindrical projection
formed on the bell crank, a nose piece or plug f¹ fitting on or into the other end
of the tubular arm, and a tie rod or stay g fitted with a cross piece or pieces and
nuts for rigidly bracing together the several parts.
The whole forms a lever of great strength, lightness and rigidity.
The nose piece or plug f¹ may carry a knife edge or centre to receive a hook,
shackle or link of any suitable kind.
This construction of lever offers great facilities for lengthening or shortening it,
as the several parts are readily detachable on slackening the nuts which secure the
tie rods or stays in place, and a longer or shorter tubular arm may then be fitted in
place.
In some cases where the final lever of the system which transmits the pull to
the connecting rod of the steel yard or weigh beam is very short, it may be a
single casting as shown in Fig. 3 instead of being built up of separate parts as
shown in Fig. 4.
By removing a plank or two in the platform A, access may be had to the levers
and working parts between or below the main girders or beams a, and any part
may be easily disconnected and removed for repairs or be as easily replaced and
readjusted.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I would here remark
that I lay no claim to the supporting of the platforms of weighing machines on
knife edges carried by two or more series of bell crank levers, which levers are
connected together in series by pull rods that serve to distribute more or less
efficiently the load over the supporting levers, the number of which may be
increased at pleasure to suit the requirements of the case, but what I claim is :-
1. Constructing and arranging platform weighing machines and weighbridges in
the manner described with reference to the Drawing.
"

page_text: 2. In platform weighing machines and weighbridges, the means described with
reference more particularly to Figs. 6, 7 and 8 of the Drawing, for coupling
together the bell crank levers in series and ensuring their synchronous oscillation.
3. In a weighing machine or weighbridge the combination with a bell crank
lever casting, such as C¹ or C2, of a detachable tubular member such as f, a nose
piece or plug f', provided with a knife edge or centre, and a stay or tie rods such
as g for bracing together the several parts, the whole constituting a lever possessing
great strength and rigidity of construction as described with reference to Figs. 1,
and 4 of the Drawing and for the purpose set forth.