Rice Lake RoughDeck FXB User manual

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FlexureBaseFloorScale
32958
RoughDeckTM FXB
Installation/Operation
Manual
SM

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Contents
1. Introduction ...........................................................................................1
1.1 Scale Components ..........................................................................................1
1.2 Operating Requirements .................................................................................2
1.3 How Flexure Levers Work ............................................................................... 3
2. Unpacking and Inspecting ................................................................... 3
2.1 Unpacking........................................................................................................3
2.2 Inspecting ........................................................................................................3
3. Installation ............................................................................................. 4
3.1 Site Preparation...............................................................................................4
3.2 Assembly .........................................................................................................4
3.3 Electrical Interface to Indicator ........................................................................5
4. Calibration and Adjustments ............................................................... 6
4.1 Calibration ....................................................................................................... 6
4.2 Mechanical Adjustments.................................................................................. 6
5. Optional Equipment.............................................................................. 7
6. Service Information .............................................................................. 8
6.1 Troubleshooting...............................................................................................8
6.2 Load Cell Replacement ...................................................................................9
6.3 Replacement Parts List and Accessories ........................................................9
7. Limited Warranty................................................................................. 11
July, 1995
Copyright © 1995 Rice Lake Weighing Systems. All rights reserved. Printed in the United States of America.
Specifications subject to change without notice.

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1. Introduction
The RoughDeck FXB is a flexure base floor scale. Unlike conventional mechanical scales, the base of a
RoughDeck FXB has no moving parts and uses thin high-strength flexure plates that always stay aligned. The
FXB is available in sizes from 18" x 24" with a 500 lb. capacity to 96" x 120" with a 30,000 lb. capacity.
NTEP certification exists for models 18" x 24" (500 lb.) through 72" x 96" (10,000 lb.).
All models use an environmentally protected single “S” type load cell recessed into the frame for protection.
Standard models include a mild steel deck, a deck plate, base, flexure plate pivoted levers, and 20 feet of
signal cable. Stainless steel covers are optional, and complete stainless steel units can be ordered. See Section
5 for a complete list of optional equipment.
1.1 Scale Components
The RoughDeck FXB has six major components (as shown in Figure 1):
Weigh platform (deck frame and deck plate)
Arigid welded frame unit with a removable deck plate upon which weight is placed. The applied load
is transmitted from the weigh platform, to the load bridge, to the levers, and then to the load cell.
Lever system
Structural members on each side of the scale are supported from the base by the fulcrum flexure. The
structural members also support the weigh platform through the lever system to the tip of the primary
lever: the primary lever is supported by the load cell.
Load cell
Electronic force measuring device mounted in a corner of the scale and rigidly fixed to the load
bridge structure. Wire rope runs from one end of the load cell to the tip of the primary lever.
Flexure plates
Flat, high-strength thin plates that transmit the load forces due to the weight applied to the platform
and to the lever system. The flexures provide a maintenance-free pivot point that supports the levers
from the base and transmits forces from the load bridge to the levers and on to the load cell.
Load bridge
Two pieces of tubing or channel iron, one on either side of the scale and tied together by two cross
members. The weigh platform is supported by the load bridge through four platform support pipes.
The load bridge is suspended from the lever system through the load flexures.
Base frame
Arigid one piece, welded unit that supports the remaining scale system. The fulcrum flexure support
stands are welded directly to the base frame.

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Load Bridge
Base Frame
Lever System
Load Cell
1.2 Operating Requirements
Electrical grounding
For systems where the scale is connected to a 120 VAC circuit, the instrument must be directly
connected to an earth ground with a ground cable that has no more than 3 ohms resistance throughout
its length and connections.
Grade level requirements
The supporting surface for the four feet of the scale must be level within 1/4" of horizontal.
Load cell excitation
Rated Excitation - 10 VDC
Maximum Excitation - 15 V
Safe static overloading capacity
Maximum - 150% of scale capacity.
Temperature
Compensated range 0°F to 150°F/-18°C to 65°C
Deck Plate
Deck Frame
Figure 1
Check Link and
Mounting Bolts
Gripper Plate
Bolts
Fulcrum Flexure
Load Flexure
Center Flexure

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1.3 How Flexure Levers Work
In the FXB, flexure levers replace pivots and bearings for the fulcrum and load and power points on the lever.
The multiple of the lever for a flexure is calculated in the same manner as a pivot and bearing lever system.
The reference point of the flexure is the center line through the flexure itself (see the following figure).
2. Unpacking and Inspecting
2.1 Unpacking
1. Remove banding straps.
Do not remove the scale from the packing skid by placing forks from
a lift truck under the base assembly unless the scale is equipped with
optional fork lift skids. Moving the scale without skids may damage
the load cell and connections.
2. Lift scale base from wooden pallet by connecting hooked-ended
chains to tubing in each corner of scale.
3. Remove weigh platform deck plate by removing four counter sunk screws from top of scale.
4. Remove weigh platform frame.
2.2 Inspecting
1. Inspect for signs of damage such as a bent frame, broken or bent flexures, and broken welds. This
visual inspection is very important and should be performed with great care.
2. Verify that all gripper plate bolts are tight (four bolts holding each flexure plate in place).
Figure 2
Fulcrum
Stand
Fulcrum
Flexure
Pipe
Lever
Load
Bridge Load Flexure
Platform Support Pipe
(Fulcrum) (Load) Lengthen Fulcrum to Load
Distance to Increase Weight
Shorten Fulcrum to Load
Distance to Decrease Weight
Fulcrum to Load
Distance
Pivot
Head
Deck

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3. Installation
3.1 Site Preparation
Because the scale must not be loaded beyond its capacity, even momentarily, do not select a site where
overweight loads would have to maneuver to avoid crossing the platform. Use the following guidelines for
site preparation:
•Avoid areas where the scale might receive damaging side impacts from items such as wheels or
forklift tines, or shock damage from falling objects.
•For scales not meant for washdown environments, avoid areas where water may cause damage.
•The interface cable between the scale and the indicator must be protected against crushing, cutting, or
moisture damage. Protect the cable by running it in conduit. Do not allow cable to lay in water.
For proper operation, the scale must be level within 1/4". Choose a site where the floor is close to this stan-
dard to avoid excessive shimming, or modify the floor at the chosen site to meet this standard. After a site is
selected:
1. Use hook-end chains to move scale base to its permanent location. Location should be level and have
a solid stable foundation. An unstable location causes inaccurate or fluctuating weight readings.
2. Verify that base rests firmly against floor on all four corner gussets. Shim between each gusset and
floor as required to attain a firm and stable mounting.
3.2 Assembly
1. Cut bands holding load cell package from lever arm and remove load cell with wire rope.
The load cell is a delicate device and can be damaged if dropped, twisted when mounting, or shock
loaded.
2. Insert a block under primary lever so it fits snugly. Remove shipping bolt and spacer. Shipping bolt is
placed between load cell support frame and nose iron (in place of load cell) during shipping.
3. The load cell is shipped with wire rope. Remove outer nut from load cell wire rope.
4. Screw inner nut on wire rope flush with top of threads.
5. Remove load cell mounting bolt from top of cell.
6. Screw short threaded end of wire rope through
bottom of load cell until flush with top.
Note:
The 3/4" spacer is used beginning with the 30" x 30"
2000 lb. model and all higher with the exception of the
48" x 48" 20000 lb. and 48" x 60" 20000 lb models
which use the 1" spacer.
Figure 3
Inner (top) nut
Nose iron
Outer (bottom) nut
Wire rope
Load cell support frame
3/4" or 1" spacer
(see note to left)

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7. Carefully lower load cell into position at an angle
so wire rope threaded rod end goes through hole
of nose iron first. If used, position spacer between
load cell support frame and load cell.
8. Position load cell so signal cable will travel
directly out exit hole in base.
9. Position load cell vertically and lift until it
touches load cell support frame. Align top hole of
load cell with mounting hole of support frame and
thread load cell mounting bolt down through
housing into load cell. Do not tighten.
10. Place bottom nut on wire rope. Do not tighten.
11. Position load cell so it is not rubbing or touching side of support frame or lever system.
12. Tighten mounting bolt.
13. Carefully raise lever nose iron and tighten bottom nut finger tight. Using a wrench, carefully tighten
bottom nut. Be sure to remove block from under primary lever.
When tightening the bottom nut, do not allow the wire rope to twist. Twisted rope causes side forces
in the cell, which cause weight errors when the scale is loaded.
14. Screw strain relief fitting into side of base.
15. Route load cell cable through strain relief fitting. Verify cable is not touching any portion of the live
weighing deck or levers.
16. Connect load cell cable to digital weight indicator.
17. Inspect under and around lever arms, pivot heads, and load bridge for any foreign material which
could interfere with live portion of scale.
18. Re-install weigh platform and deck plate. The scale base is ready for calibration.
Note:
The weigh platform frame and scale base are match marked on the corner near the load cell for proper re-
assembly.
3.3 Electrical Interface to Indicator
20 feet of 4-wire cable is supplied to connect the scale to the weight indicator. Use the wiring scheme in the
following table to connect your RoughDeck FXB.
Color Code Function
Red + Excitation
Black – Excitation
Green + Signal
White – Signal
To prevent electrostatic discharge, ground the scale base to the earth ground terminal of the same AC power
source that is used to power the indicator.
Figure 4

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4. Calibration and Adjustments
4.1 Calibration
1. Zero balance digital weight indicator.
2. Place test weights equal to 70% - 80% of scale’s capacity on weigh platform and adjust weight
indicator span for correct reading.
3. Remove test weights and check zero.
4. Repeat Steps 1 - 3 if weight indicator does not return to zero.
4.2 Mechanical Adjustments
The corners of the scale base are preset. If corners have extreme differences, check for bent flexures, broken
welds, or foreign objects in the corners.
1. Apply test weights equal to 25% of scale capacity to each corner in sequence and observe weight
indicator. Record these weights for reference.
2. If corner shift reading is within tolerance, do not make any mechanical adjustments. If it is not within
tolerance, proceed to step 3.
3. Remove deck plate and weigh platform frame.
4. Loosen all check link mounting bolts (see Figure 1).
5. Loosen top and bottom load flexure gripper plate bolts on corner to be changed (see Figure 1). You
do not have to completely remove bolts.
6. Use Figure 2 and exercise below as a guide and perform one of the following:
•Add shims to increase fulcrum to load distance which increases weight reading for corner being
adjusted.
•Remove shims to decrease fulcrum to load distance which decreases weight reading for corner
being adjusted.
Exercise: Determining Shim Amount
For example, if:
Load error = 3 lbs.
Load arm distance = 4"
Load on platform = 1000 lbs.
Then your shim would be .012.
shim thickness = error (lbs.) x load arm (in.)
load on platform (test weights)
Center Load Fulcrum
Flexures
Distance = Power Arm Distance =
Load Arm
.012 = 3 (lbs.) x 4 (in.)
1000

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Shims are available in .010" and .030" thicknesses. Weight readings change in a linear way propor-
tional to shim thickness. For example, if adding a .010" shim increases weight reading 2 lbs. on that
corner, a 030" shim will increase it 6 lbs.
7. Tighten all check link bolts.
8. Re-install weigh platform and deck plate.
9. Re-check corners per step 1.
10. Recalibrate scale as described in section 4.1.
5. Optional Equipment
The following options are available for the RoughDeck FXB:
Fork lift skids
Two 8" channels mounted on customer-specified centers.
Fork lift skids with weight indicator column
Two 8" channels mounted on customer-specified centers with one channel extended 12" and equipped
with a bolt-on pipe stand weight indicator column. The weight indicator display is 54" above the
floor. For models larger than 48" x 60", you must consult your distributor to determine the appropriate
weight indicator column.
Epoxy-painted base
An epoxy-painted base with stainless steel hardware.
Stainless steel sheet metal platform covers
Stainless steel covers for the entire deck top.
Stainless steel construction
Stainless steel construction of the entire scale base.

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6. Service Information
6.1 Troubleshooting
Problem Probable Causes
Shift error
Erratic readings
Non-linear weight reading
Corner error
Zero change
Center flexure offset from center line
Corners not shimmed tightly to floor
Nose-iron on power lever too high or too low
Pivot heads need shimming
Bent flexures or cable assembly
Center leveling bolts not down far enough, or down too low
Corners not shimmed tightly to floor
Ground shield not connected to cannon plug or meter shield
Loose connection in junction box
Center flexure offset from center line
Damage to load cell
Misaligned flexure or cable assembly
Nose-iron on power lever too high or too low
Pivot heads need shimming
Corners not shimmed tightly to floor
Loose gripper
Misaligned flexure or cable assembly
Pivot heads need shimming
Corners not shimmed tightly to floor
Damaged load cell
Live assembly touching dead assembly
Loose gripper
Misaligned flexure or cable assembly
Shipping block not removed during unpacking
Obstruction under load bridge (probably at corner)