Service manual

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3.14 Reassembling the Platform
Use the following procedure to reassemble the weigher platform. See Figure 5 on page 16 for location of
numbered parts.
1. Grease and replace lower load strips (19), retainers (17), needle bearings (20), and upper load strips
(18), with chamfered corners on upper load strip facing links.
2. Grease platform buttons (43).
3. Carefully insert platform into base.
4. Holding platform and base together, turn the weigher upside down.
5. Insert spring housing (3) and springs (7).
6. With a 1/4” Allen wrench, install spring retaining bolts (6) and washers (5) by turning in a clockwise
direction until hard stop is felt. Then turn back counterclockwise 3/4 of a turn.
7. Use a screwdriver to pry ends of platform away from base. Platform should move a small amount and
before stopping. If platform cannot be separated, back off spring retaining bolts 1/4 turn.
8. Adjust spring bolts until 0.015 to .030 inches of movement occurs between platform ends and base
before hard stop is felt.
9. Install disk seals (4) and snap rings (8).
10. Turn weigher over, base down. Use a 3/32” Allen wrench to tighten set screws (51). Seal set screws
and disc seals with silicone and let silicone dry.
11. Platform assembly is now complete.
4.0 Calibration Verification
Each PW 400/PW 500 weigher is fully calibrated and tested at the factory before shipment. The weigher is
checked at five or more points to ensure accuracy of calibration over the weighing range of the scale. Special
equipment is used to simulate vehicle passage and assure that calibrations are stabilized and will not change
with normal usage. See Section 1.3 for calibration tolerances.
Verification of the accuracy of a static weigher consists of placing known certified weights, or calibrated
force, on the platform of the weigher and then comparing the weight reading on the display to the weight or
force on the platform. Weighers can be checked individually or in pairs. A Force Load Calibration Press is
recommended for operator safety and ease of operation. Procedures for checking calibration on a force load
machine are as follows:
1. Position weigher on the press/surface.
2. Place a 10 inch by 10 inch steel plate that is at least 1 inch thick on the platform. The plate distributes
the force load evenly across the weigher platform load buttons and prevents point loading the center
of the platform.
3. Turn the weigher ON and allow to warm-up for 5 minutes.
4. Before checking the calibration, exercise the weigher by applying a force of weigher capacity to the
platform and then remove the force. Repeat this exercise for a total of 3 times.
5. Press the ZERO button to zero the weight displayed. (This tares off the weight of the plate.)
6. Check for calibration accuracy at the following five (5) points: 2,000 lbs or 1,000 kg; 5,000 lbs or
3,000 kg; 10,000 lbs or 5,000 kg; 15,000 lbs or 7,000 kg; 20,000 lbs or 10,000 kg.