Rice Lake Z6 Single-Ended Beam, SS Welded-seal, IP67, OIML C3 - Manual (Page 24)

20 Load Cell and Weigh Module Handbook
13.0 Load Cell Mounting Hardware Safety Guidelines
Install only load cell mounting hardware and assemblies that have been specifically designed for use in tank, hopper or hanging
scale applications. Often, the use of an inferior-grade product results in component failure, which risks equipment damage and
personal injury. These simple suggestions are provided to help minimize your exposure to vessel-scale installation hazards.
Safety Backup
If failure of one or more load cell hardware assemblies could
cause injury or damage, a safety backup (safety chains, safety
rods, etc.) must be used. Also, the assemblies should be
inspected routinely for damage, excessive wear or corrosion,
and replaced if necessary.
Estimating Gross Load
To select the correct load cell or load cell hardware for a given
application, it is necessary to know the total weight on the
scale, including the net weight of product, the tare weight of
the vessel, and the weight of the platform, tank or hopper, as
appropriate.
Safe Load
Do not exceed the safe-load figures listed in this catalog for
any load cell hardware. Where shock loads are present, it
may be ne cessary to derate these safe-load figures
depending on the severity of the shock load.
Load Distribution
In multiple load cell applications, make certain that the weight
is evenly distributed between all cells.
Threaded Connections
Be sure that all threads of a threaded connection are in
engagement. For example, an eye bolt that is screwed into an
S-type load cell should protrude slightly on the opposite side.
Jam Nuts
Lock any threaded connections with a jam nut to prevent
inadvertent disassembly. If a load is suspended from a single
load cell, make sure the load cannot rotate, as this may loosen
the jam nut.
Wire Rope Assemblies
With wire rope assemblies, do not twist the rope during
assembly or disassembly. For example, do not remove a
frozen nut from one end of a rope assembly by holding the
opposite end.
Attachment Points of a Load Cell Hardware Assembly
Ensure that the attachment points of a load cell hardware
assembly are aligned properly and that the assembly is
essentially vertical.
Swaying in a Suspended Vessel Scale
If there is excessive swaying in a suspended vessel scale,
apply horizontal checking to reduce the amplitude.
Hopper Scales: Guarding Against Contamination
With hopper scales, guard against contamination of the
product being weighed as a result of the failure of the load cell
or hardware assembly. For example, do not locate a wire rope
assembly over a hopper scale where broken strands of wire
could fall into the weighing vessel, contaminating the product
being weighed.
Selecting Steel Rod or Any Other Weight-Bearing
Components
Select steel rod or any other weight-bearing components so
that their minimum tensile strength is at least four times the
total weight carried by that component. Note that threaded
rod is generally made from a low tensile strength mild steel
which should be checked for tensile strength before use in
any suspended vessel scale.
NOTES: Based on dry assembly. Variables such as
lubrication, plating, etc. may reduce the values listed above as
much as 20% and must be taken into consideration. General
formula for calculating torque is as follows: Torque in Inch/lbs
= 0.2 x Nominal Diameter of Screw x Load in lbs, where load
= 80% of yield strength, expressed in lb, not pounds per
square inch. The tension induced in a cap screw may be
checked by measuring overall length before torquing
Cap screw
diameter
Recommended Torque (ft lb)
Heat-treated 1038 hex
head SAE Grade 5
Alloy hex head SAE
Grade 5
UNC UNF UNC UNF
1/4" 11 13 12 15
5/16" 21 23 25 30
3/8" 38 40 50 60
7/16" 55 60 85 95
1/2" 85 95 125 140
9/16" 125 140 175 195
5/8" 175 210 245 270
3/4" 300 330 425 460
7/8" 450 490 660 700
1" 680 715 990 1050
1-1/8" 885 990 1470 1655
1-1/4" 1255 1380 2100 2310
1-3/8" 1635 1875 2750 3110
1/4" 11 13 12 15
Table 13-1.