Fit the DIG™ GPS pendulum mount

The DIG™ receiver rides on a pendulum at the top of the stick. Tube #1 welds to the side of the stick. Tube #2 slides into it and carries the pivot. The counterbalance plate hangs from that pivot, so the receiver stays upright as the stick swings.

Line the pivot up over the stick's pins now and calibration is simpler later.

Before you start

• You've read the DIG safety rules.
• Before you lock out: the stick is hanging straight down (vertical), so you can line up the pivot with a plumb bob.
• The machine is on level ground, engine off, key out, hydraulic pressure relieved, and an approved lock-out/tag-out device is on.
• The machine battery is disconnected.
• All electronics, sensors and harnesses within 1 m (3 ft) of the weld are removed or isolated.
• No open flames nearby, and someone is on fire watch with a Class ABC extinguisher.

You need: Tube #1, Tube #2, the counterbalance plate with its pivot bolt, felt washers, metal washers and spacers, the GPS rod (5/8 in. thread) with its lock nuts, your GPS receiver, a welder and welding protection (mask, gloves, eye protection), a work platform or fall arrest, a grease gun, and a second person to watch clearances.

How long it takes: no set time; the tacking and lining up take the longest. The final welds come later, after the whole kit is fitted and checked.

Fit Tube #1

1. Hold Tube #1 against the side of the stick, near the top

   Tube #1 sticks straight out from the side plate of the stick, flange end out. Mark the spot.

   

2. Angle it so the pivot will sit above the boom pin

   Tube #2 will rise from Tube #1 to the pivot F. Set Tube #1 so that F ends up straight above the boom pin H, and so the flange bolts won't be in the way when Tube #2 goes in.

3. Tack weld Tube #1

   Tack it only: a few small welds that hold it in place. The full welds come after the whole kit has been checked through every position.

Fit Tube #2 and line up the pivot

1. Slide Tube #2 into Tube #1

   Push its short round end into Tube #1, with the arm pointing up. Push it in far enough that the pivot at the top of the arm clears the boom and everything else on the machine.

   

2. Line up F over H and B

   Turn Tube #2 until the pivot F sits on one straight up-and-down line with the boom pin H and the bucket pin B. Check it with a plumb bob from F with the stick hanging vertical.

3. Can't line it up? Measure the offset and write it down

   A small level offset is acceptable when the mount can't go in the ideal way. With the stick vertical, measure the level distance from F across to the H–B line, note whether F sits toward the cab or away from it, and write it down. You enter it during calibration (Enter the GPS offset). With an offset, accuracy drops slightly at extreme angles.

4. Tack weld Tube #2 to the removal flange

   Same welding rules as above. Tack it to the flange: the bolted plates let you take the whole GPS mount off later.

   

Hang the counterbalance plate

1. Lay out the pivot hardware

   The pivot bolt, a spacer, metal washers and two felt washers.

   1 2 3

2. Bolt the plate to the pivot

   Put the bolt through Tube #2's pivot and the counterbalance plate, with a felt washer on each side of the pivot, and the washers and spacer as laid out.

   

3. Tighten until the felt washers damp the swing

   The plate should still swing, but slowly. Don't over-tighten: the receiver must be able to level itself while you work.

4. Grease the pivot

   Pump grease into the grease nipple on top of the pivot. Do it again regularly while the machine is working.

Fit the rod and the receiver

1. Thread the rod through the plate's base

   Thread the 5/8 in. rod through the hole in the base of the counterbalance plate. Set its height so the receiver will clear everything, then tighten the lock nuts above and below the base.

2. Screw the receiver onto the rod

   Screw your receiver onto the top of the rod until it is snug. Then check nothing on the receiver touches the plate.

Check the mount through full travel

1. Check F still lines up with H and B

   With the stick still hanging vertical and the machine locked out, check with the plumb bob.

2. Take the lock-out off and start the machine

   Everyone off the platform and clear of the stick first. Reconnect the battery, then the operator starts the engine.

3. Move the stick slowly all the way in, then all the way out

   The operator moves it slowly while a second person watches the mount from a safe distance. Stop at once if anything touches.

4. Watch the receiver stay upright

   Tube #2 tilts with the stick, but the counterbalance plate should hang straight down, keeping the receiver upright. Some swing can't be avoided, but it should never reach extreme angles.

5. Lock the machine out again

   Lower the bucket, shut the engine off, take the key out, relieve the pressure, disconnect the battery and fit the lock-out device before the next page.

Common mistakes

• Pivot bolt clamped tight, so the pendulum can't swing and the receiver tilts with the stick.
• A downward radio antenna touching the counterbalance plate.
• No grease on the pivot.
• Final-welding before the full-travel check.
• Not measuring a horizontal offset between F and the H–B line.

Next: Mount the stick and bucket sensors. Problems later: Fix DIG problems.