Weighbridge and method of producing it

The present invention relates to a weighbridge consisting at least partially of cast concrete portions, and a method of producing such a bridge. With the object of increasing the accuracy of a weighbridge, of facilitating and cheapening the production of a weighbridge, it is proposed according to the present invention that the bridge (1) should be disposed resting against two beams (5) which are disposed along the long sides of the bridge and supported by transmitter members (6), that at least two transverse beams (7) are disposed secured between the longitudinal beams (5) of the bridge, preferably at the short sides of the bridge, that the cast portions of the bridge are surrounded by an edge lining (3) preferably of sheet metal bearing downwards against the tops of the beams (5, 7), and that the cast portions preferably comprise a corrugated or profiled bottom metal sheet (12) resting substantially against the longitudinal beams of the bridge. As a result of the invention, it becomes possible to cast the weighbridge on site above the longitudinal beams, and the mould formed by the edge lining, beams and metal sheets does not have to be removed after the cast concrete has set. (FIG. 2).

The present invention relates to a weighbridge, at least partially 
consisting of cast concrete parts, and a method of producing the 
weighbridge. 
It is already known to manufacture weighbridges from cast concrete or as 
all-welded steel constructions. The cast weighbridges, which are cast, for 
example, directly in a weighing pit, therefore require a special mould 
dimensioned to take up the whole weight of the weighbridge. It is often 
necessary to carry out a stamping of the mould which is particularly 
difficult in view of the fact that the weighbridge is cast in a special 
weighing pit which is not wanted too deep for reasons of cost, which means 
that the space below the weighbridge is limited. After the setting of the 
concrete, the mould has to be broken up and removed through a manhole in 
the weighbridge, which work is time-consuming and therefore expensive. A 
further expense in connection with casting known weighbridges is that they 
have to be made with special beam sections adapted to bear against 
transmitter members. 
The use of weighbridges consisting of all-welded steel constructions 
eliminates many of the disadvantages associated with the casting of 
weighbridges. For various reasons, a welded weighbridge has to be made 
with great accuracy which means that it is extremely inconvenient to weld 
the weighbridge together on site in the weighing pit. A finished 
weighbridge may have dimensions of 3.times.18 m, which means that special 
arrangements have to be made for such a weighbridge to be able to be 
transported from the place of manufacture. An all-welded weighbridge is 
nevertheless preferable since its lower weight in comparison with the 
weight of a cast weighbridge leads to more accurate weighing. 
The present invention provides a weighbridge and a method of producing it 
which to a large extent eliminates the problems and disadvantages which 
exist with known weighbridges. A weighbridge according to the present 
invention has several of the advantages of a welded weighbridge but none 
of the disadvantages which are associated with the production of known 
cast weighbridges. Thus, the object of the present invention is to provide 
a weighbridge which can easily be produced directly in a weighing pit, 
which has considerably lower weight in comparison with known cast 
weighbridges and which, in addition, is cheaper to produce than known 
weighbridges. 
The objects given above are achieved according to the present invention by 
giving the weighbridge and the method for its production the 
characteristics given in the patent claims. 
By casting the weighbride directly on a mould, preferably of metal, which 
mould does not need to be removed after the setting of the concrete and 
which rests directly against two beams disposed along the long sides of 
the weighing pit and supported by the transmitter members, a comparatively 
light weighbridge with the necessary strength is obtained. Transverse 
beams between the longitudinal beams are preferably bolted to these and at 
the same time constitute a support for or part of the mould. The mould is 
bounded by an edge lining which bears with a sealing action against the 
tops of the beams. The edge lining only needs to be dimensioned to take up 
the stresses which occur during the casting of the concrete in the mould. 
A preferably corrugated or profiled metal sheet is disposed on the beams 
with a sealing action against the tops of the beams. A plane-profiled 
metal sheet is preferred since this permits the placing of reinforcing 
iron in each profiling, while at the same time the volume of concrete can 
be reduced without detriment to the necessary strength of the weighbridge. 
As a result of the fact that the edge lining is bounded at the top by a 
T-beam, to the web of which there is secured a metal sheet disposed close 
to the tops of the beams, objects are effectively prevented from becoming 
wedged between the edge of the weighbridge and the surrounding edges of 
the weighing pit, adjacent to the weighbridge. An edge lining thus shaped 
also permits an easy joining at the corner portions of the mould. 
Placed between the corrugated metal sheets and the tops of the beams is a 
seal which is shaped in accordance with the corrugations of the metal 
sheet with the object of preventing the concrete from leaking out during 
the casting of the weighbridge. The corrugated metal sheets may 
appropriately be screwed firmly to the tops of the beams to bring about a 
compression of the seal. 
Part of the weighbridge can be formed as continuous gratings through which 
grain, for example, can be unloaded for further conveying to a grain 
conveyor placed under the weighbridge. 
The cast concrete portions of the weighbridge may also be given an 
inclination towards the centre where an opening is situated for water to 
run away. Directly below the opening in the weighbridge, wells may 
appropriately be provided in the bottom of the weighing pit which means 
that the main part of the bottom of the weighing pit can be kept dry. 
When the bottom of the mould consists partially of the longitudinal beams 
and the tops of the transverse beams, it is advisable to fix reinforcing 
iron to said tops. 
With the object of stiffening the edge lining and locating this during the 
casting of the concrete, spacing elements are welded to the upper portion 
of the edge lining, that is to say in the T-beam, and in an edge lining at 
the upper edge portion of the weighing pit. When the concrete has set, 
these spacing members are removed, whereupon the weighbridge is ready for 
used.

FIG. 1 shows the finished weighbridge 1 in position in a cast weighing pit, 
the later edges 2 of which are closely connected to the edge lining 3 of 
the weighbridge. The weighbridge shown here is entirely cast in concrete 
apart from two centrally situated manhole covers and drainage hole covers 
4. The top of the weighbridge 1 has a fall towards the hole covers 4. 
The production of the weighbridge 1 will now be described with reference to 
FIG. 2. Two longitudinal beams 5a and 5b are first placed in the finished 
weighing pit and secured in at least four transmitter members 6, that is 
to say at least two transmitter members under each longitudinal beam 5. A 
transverse beam 7 is disposed at least at each short side of the 
weighbridge and is there bolted to the longitudinal beams 5. For this 
purpose, the transverse beams 7 are provided with transverse flange plates 
which are bolted to the webs of the longitudinal beams. The frame formed 
by the beams 5 and 7 thus constitutes a support for the weighbridge which 
consists wholly or partially of cast portions. 
In order to render possible a casting of the weighbridge, an edge lining 3 
is disposed round the cast portions of the bridge. FIG. 3 shows an 
embodiment of the edge lining 3, the upper portion of which consists of a 
T-beam 8 at the web 9 of which a plate 10 is directed down towards the top 
of the longitudinal beam 5 and secured to this with a sealing action by 
screwing or welding. The outer portion 8a of the T-beam eliminates, to a 
large extent, the risk of objects becoming wedged between the weighbridge 
and the side wall of the weighing pit, while at the same time the web 9 of 
the beam forms a drip nose. 
Reinforcing irons 11 and 11a are welded to the tops of the longitudinal 
beams 5 and of the transverse beams 7. 
Placed between the longitudinal beams 5 is a plane-profiled metal sheet 12 
which sheet forms the bottom of the mould in which the concrete is to be 
cast to form the weighbridge. A seal 13 is placed between the metal sheet 
12 and the tops of the longitudinal beams 5. If necessary, a seal is also 
placed between the metal sheet 12 and the tops of the transverse beams 7 
with the object of creating a sealed mould which prevents leakage of 
concrete during casting of the weighbridge. Since the sheet metal 12 is 
not to be removed after the weighbridge has been finished, the metal sheet 
may appropriately be galvanized. 
FIG. 4 shows the installation of a manhole and drainage hole cover 4 in the 
weighbridge. The hole cover 4 is surrounded by a frame 14 resting against 
two transverse beams 7', likewise provided with reinforcing iron 11', 
which means that the sheet metal 12 is cut off and sealed at the tops of 
the transverse beams 7'. At the height of the hole cover 4, the sheet 
metal 12 is disposed resting partially against the longitudinal beams 5 
and partially against a lower portion of the frame 14 of the hole. 
If a weighbridge is desired with a larger grating opening, for example for 
grain, the procedure is the same as given above in connection with the 
hole cover 4. 
When the edge lining 3, the sheet metal 12 and possible hole covers 4 have 
been placed in position and possibly sealed against the tops of the beams 
5 and 6, the mould thus formed is ready for filling with concrete. Spacing 
elements 15 (FIG. 3) locate the upper portion of the edge lining at the 
upper wall edge 16 of the weighing pit, consisting for example of an angle 
section, after which the casting can begin after the necessary 
reinforcement has been inserted in the mould. The upper portion of the 
edge lining 3 may appropriately be provided with reinforcement 17 to 
ensure the edge strength of the weighbridge. 
The invention is not limited to the example of embodiment shown, but 
modifications can be made within the scope of the following patent claims.