This guide describes how to replace the pin engagement mechanism in MiR Shelf Carrier 250.

Things you'll need

• A MiR Shelf Carrier 250 pin engagement mechanism from MiR

• Screwdrivers with the following heads:

  • T45, T20, and T10

  • 7 mm hex socket

• Torque wrenches for the following:

  • 2.5 Nm with a T20 head and a 7 mm hex socket head

  • 15 Nm with a T45 head

• Cable ties

Before replacing the pin engagement mechanism

Step 1: Turn off the robot and disconnect the battery. To disconnect the battery, follow these steps:

1. Remove the rear cover by pressing the two white buttons and pulling off the cover. When removing the cover, un-click the two bottom corners first and then the two top corners.
   
2. Turn the Battery lock switch clockwise to release the Battery lever.
   
3. Pull the Battery lever down to disconnect the battery.
   
4. Turn the Battery lock switch counter-clockwise to lock the battery lever again.

Step 2: Remove the top cover by unscrewing all 14 screws in the top cover using a T20 screwdriver.

Step 3: Remove the top compartment covers from the interface compartments by unscrewing the eight screws with a T10 screwdriver.

Step 4: Disconnect the GPIO, Safety-related functions, and Emergency stop connectors from the robot's top interfaces. These are the cables labeled 4-8.

Step 5: Remove the weights in the four corners by unscrewing the two screws in each set.

Step 6: Remove the weight brackets by unscrewing the large screws and the two nuts on each bracket. Use a T45 screwdriver for the large screws and a 7 mm hex socket screwdriver for the nuts.

Replacing the pin engagement mechanism

Step 1: Cut the cable ties around the actuator cables.

Step 2: Unscrew the eight nuts keeping the actuator assembly bracket in place using a 7 mm wrench.

Step 3: Place the actuator assembly on top of the electronics bracket, and remove the eight nuts fixing the pin engagement mechanism in place. Use a 7 mm wrench to unscrew the nuts.

Step 4: Remove the old pin engagement mechanism and replace it with the new one.

Step 5: Remove the cable ties once the pin engagement mechanism is placed so its mounting holes are aligned. Do not lift the pin engagement mechanism after removing the cable ties.

Step 6: Screw on the eight nuts to fix the pin engagement mechanism in place and the eight nuts to fix the actuator assembly in place. Tighten the nuts to 2.5 Nm.

Step 7: Fix the actuator cable to the pin engagement mechanism using three cable ties. Make sure the heads of the cables ties are below the surface.

Reassembling the robot

Step 1: Mount the weight brackets and weights back on the robot. Tighten the large screws to 15 Nm and the nuts to 2.5 Nm.

Step 2: Reconnect the top interface connectors, and mount the top compartment covers by screwing in the four screws in each cover with a T10 screwdriver. Do not tighten the screws too much, and make sure to pull the end of the antenna cable through the antenna hole.

Step 3: Mount the top cover back onto the robot. Start by screwing in the four center screws and then the 10 outer screws using a T20 screwdriver. Make sure to tighten all of the screws to 2.5 Nm.

Step 4: Reconnect the battery and turn on the robot. You have now finished replacing the pin engagement mechanism.

Testing

Go to Setup > I/O modules and under MiR internal I/Os complete the following sequence and verify that the shelf carrier performs as expected:

1. Under Outputs, select 3. Verify that the carrier pins rise up.
   

2. Once the pins are raised, verify that 3 under Inputs is green.
   

3. Under Outputs, select 2. Verify that the carrier pins lower into the robot.
   

4. Once the pins are lowered, verify that 2 under Inputs is green.
   

If the pins were raised and lowered as expected and the correct input feedback was received, MiR Shelf Carrier 250 is correctly installed. If not, check the cables you connected to the top electrical interfaces.