MSB Flintec
26 November 2014
Load cell mounting brackets are attached to the superstructure by means of welding or bolting. In order to provide for the
mounting of load cells and mounting brackets (illustrated in later sections), some modification to the superstructure may
be required. The modifications may be as simple as providing a flat surface for bracket welding or may be as extensive
as providing a recess in the under frame for the mounting of the load cells.
Modification to the superstructure will vary according to the specific type of installation to be performed; whether it is
for a trailer suspension subframe assembly or for truck frame mounted systems supporting entire payload carrying
superstructures. Outboard mounted load cells may only need space to weld or bolt load cell mounting brackets, while an in-
line mounted load cell system will need holes drilled in the under frame of the superstructure for the load cell mounting bolts.
Whenever making modifications to a structure, care must be taken to provide for bolt strength and rigidity (stiffness) for
the finished installation. Every structure will deform (bend, twist or sag) to a certain degree when carrying a load. The
installer must ensure that the modified structure is strong enough to prevent not only permanent (elastic) bending so
that upper structural elements will not contact lower elements and create an alternative load path around the load cells.
Excessive frame bending can be prevented by either adding a ‘glove’ (a structural supporting sleeve) to the frame, or by
adding additional load cells in that area for more support.
Frame Stiffeners:
If the frame section above the load cell is an open section, such as a channel or ‘
I
’ beam, web stiffeners are required to
avoid frame twist (see illustration below). The stiffeners are located near the ends of each bearing plate for inverted load
cell mounting, or between the mounting holes for load cells installed with the bearing plates beneath the load cells.
Recess Mounting:
Often the most practical method for installing on-board frame mounted scales (particularly with an in-line mounted
system) without an undesirable height increase of the trailer or body, is to provide a recess in the superstructure under
frame. A general recommendation for this approach is shown in the following illustration. The installer should assure that
any modified structure will retain the strength and stiffness properties of the original structure.
Preparation
5
Frame stiffeners
(ribs or gussets)
10 mm (3/8") thick
Cover plate or glove
10 mm (3/8") thick
Flange 20 mm (0.75") thick
Don't allow bolts
to protrude here