Rice Lake Z6 Single-Ended Beam, SS Welded-seal, IP67, OIML C3 - Manual (Page 37)

Weigh Modules: Tension Mounting (S-Beam) 33
17.0 Weigh Modules: Tension Mounting (S-Beam)
17.1 Introduction
Suspension mounting with tension S-beam load cells is often
used for light to medium vessels where an existing overhead
structure may be used to suspend the vessel.
17.2 General Mounting Principles
Figure 17-1 illustrates the correct way to apply load to an
S-beam load cell.
1. The surface from which the cell is suspended should
be rigid and provide minimal deflection under loads.
2. The entire suspension should be as long as possible
with the load cell placed approximately at the center.
3. The center line of the top and bottom rods should
pass through the load cell’s load holes. The center
line through the assembly should be vertical.
4. The load cell cable should emerge from the fixed end
of the cell so that it does not affect accuracy.
5. The extremities of the suspension should be
attached to the structure and vessel in such a
manner that they are free to move. At a minimum,
u s e s p h e r i c a l w a s h e r s e t a s i l l u s t r a t e d i n
Figure 17-1.
6. Use a suitable hardware assembly such as eye bolts
or the ITCM system at the load cell to minimize the
transmission of extraneous forces.
Figure 17-1.
ITCM Mounts
The ITCM assembly is a particularly convenient method of
suspending a weigh vessel. The combination of clevises and
rod-end ball joints ensure that forces detrimental to accurate
system performance are isolated from the load cell. In addition,
the unique electrical isolation provided to the load cell by this
assembly helps prevent damage from stray currents.
Allowable Movement
Figure 17-2 illustrates the use of the ITCM weigh module. This
mounting arrangement prevents most of the potential problems
caused by extraneous forces acting on S-beam load cells.
Figure 17-2.
Construction and Features
1. The ITCM consists of a high-precision rod end ball
joint which is screwed into each end of the S-beam.
The rod end ball joint has a “ball” which is free to
rotate in a TFE bearing; see Figure 17-2(c). A clevis is
attached to the rod end ball joint using a shoulder
screw.
2. This arrangement provides excellent alignment
between the center lines of the rods and the center
line through the cell’s load holes.
3. This arrangement allows movement in the directions
indicated by the arrows and also allows rotation, thus
ensuring that extraneous forces are not transmitted to
the load cell.
4. The ITCM also incorporates an insulating system
which will not allow the flow of stray currents through
the load cell. The parallel ground strap provides
further protection with an alternate path to ground.
5. ITCMs are available in mild steel in capacities from
100lb to 20,000lb using the RL20000 load cell.
Stainless steel versions are available in capacities
from 100lb to 5,000lb
6. 20,000lb ITCM assemblies do not have TFE lined
rod end ball joints.
NOTE: A single ITCM is often used to convert a mechanical
truck or hopper scale to electronics. This allows you to take
advantage of process control or data collection options
available with electronic weighing. The conversion can be
accomplished by inserting an ITCM assembly in the steelyard
rod without affecting the operation of the mechanical beam or
dial which may be retained as a backup.
a b c