Rice Lake BenchMark SLHE - Manual (Page 12)

8 Benchmark Series Single Point Bench Scales
5.0 Load Cell Replacement
5.1 10"x10" and 12"x12" SL Models
1. Unplug AC power from indicator and disconnect load cell cable from indicator.
2. Lift off scale top cover.
3. Locate two upper load cell screws. Use 7/16" wrench to unscrew and remove those two load cell screws.
Important Do not remove four spring-loaded screws that attach load plate to spider assembly.
4. Lift off load plate/spider assembly as a unit.
5. Remove spacer between load plate and load cell and set it aside.
Lift up
Protection
Screw
Overload
Protection
Screw
Load Cell Screw
Load Cell Screw
Top Sub-Assembly
Load Plate / Spider Top Cover
Figure 5-1. Load Cell Mount Diagram
6. Turn scale over and back off overload protection screw one complete turn. Completely unscrew and
remove lift up protection screw.
7. Use 7/16" wrench to unscrew and remove two lower load cell screws. The load cell and cable can now be
removed from scale. Do not lose shim beneath load cell.
8. Thread cable of replacement load cell through rubber grommet. Position load cell on shim and screw in
two lower load cell screws. Torque to 80 in-lb.
9. Replace lift up protection screw by screwing it in until it lightly bottoms, then back it off 1/4 turn.
10. Turn scale right side up. Position spacer on load cell, then place load plate/spider assembly into position.
Screw in two upper load cell screws. Torque to 80 in-lb.
11. Using an accurate caliper, check compressed spring length on four overload springs (Figure 5-2). If
necessary, adjust spring length to specifications shown in Table 5-1. Replace top cover and re-level scale if
necessary.
12. Connect load cell cable to indicator.
13. Recalibrate scale as described in Section 3.0.
14. Adjust overload protection screw on bottom of scale by loading scale to 125% capacity. Place this weight
on top cover, centered on platform. Use a hex wrench to screw in overload protection screw until it touches
load cell, then back off 1/6 turn. Recheck calibration.
Scale Model Spring Length "H"
10 x 10 - 5 Lb 1.06
10 x 10 - 10 Lb .94
10 x 10 - 20 Lb .97
10 x 10 - 30 Lb 1.43
12 x 12 - 30 Lb 1.43
12 x 12 - 50 Lb 1.12
12 x 12 - 100 Lb 1.16
Table 5-1. Overload Spring Length
H
±
.0 2
Figure 5-2. Spring Height