This guide describes how to service the MiR pallet lift and shelf lift top modules for MiR500, MiR600, MiR1000, and MiR1350.

The images in this guide show a MiR EU Pallet Lift 500, but the procedure is the same for all other lifts.

Service intervals

Table 1.1 Describes the service intervals in which you should perform regular lift maintenance. Each task links to the relevant set of instructions. Make sure to follow the instruction under Before servicing the lifts before starting the service tasks.

If you use the lifts for MiR1000 and MiR1350 with moderate to low payloads, they are designed to withstand 90 000 cycles before they need service with a large kit, which includes new actuators.

If you mostly use the lifts with maximum or near maximum payload capacity, you need to apply the small and medium service kits as well at 30 000 cycles intervals.

Kit overview and contents

There are twelve different kits depending on the type of lift you have and which service interval you need.

If you have a MiR500 lift, you must check which revision you have. To see the difference, remove the covers and check for the following: 

• Rev. 1 does not have an external limit switch. The limit switches are integrated in the actuators and are not immediately visible.

• Rev. 2 has an external limit switch that can be seen when you remove the cover.
  

Things you will need

• Wooden blocks

• A Philips screwdriver (small)

• A flat-head screwdriver (small)

• A flat-head screwdriver (large)

• A Pipe wrench (small)

• A retaining ring tong

• Nose pliers

• A hammer (preferably rubber)

• Cable ties

• Hex keys or a screwdriver with a set of Hex bits

• Large Hex tool, or an extension, to easily break bolts loose

• Loctite 2700 (or similar retaining adhesive)

• Grease

• A 45 Nm torque wrench

Before servicing the lifts

1. Get the lift in a raised position.

2. Turn off the robot, and disconnect the battery. See the user guide for your robot application.

3. Demount the lift from the robot. See the user guide for your robot application.

4. Place the lifts on a table with a suitable work height and with enough room for tools and parts. The lifts consist of four actuators or 'corners'. We advise servicing one actuator at a time to avoid confusion with parts from different actuators.

   

Every 30 000 lift cycles

Replacing the actuator sleeve bearings

Remove the push pins by following the instructions in Replacing the push pins and retaining rings. Replace the four actuator sleeve bearings, and then mount the pushpins back in place. You can reuse the old pushpins.

Greasing the POM gliders

1. Locate the POM gliders right next to each actuator, with two or three screws fastening each glider.

   

2. Wipe away the grease on the POM gliders using a clean cloth.

3. Apply enough grease on the glider to cover the entire surface with a thin layer. The pattern applied by MiR is shown below. One bag of grease should be enough for all four POM gliders.

   If you are going to service other parts of the lift, finish servicing those parts before applying the grease.

   

Tightening the pivot bolts

Check that all 24 pivot bolts are tightened to 45 Nm. There are six pivot bolts for each actuator.

Checking the actuator cables

Inside the lift, check that all of the cables are intact. There should be no signs of damage or wear on the wires or cables. Make sure to pay special attention to cables around the openings to the robot. Cables can get pinched between the robot's top plate and the bottom of the lifts.

If any of the cables or cable connectors appear damaged, replace the cable.

Every 60 000 lift cycles

Replacing the top cover screws

When you demounted the lift, you removed all of the top cover screws. Discard these screws. When mounting the lift back on the robot, make sure to use new screws included in the maintenance kit.

Replacing the actuators

1. Take a picture of the lift from above before removing the actuators. You can use this image to verify that you have correctly replaced the actuators. Replace one actuator at a time to avoid confusing actuators and connecting cables incorrectly.

2. Remove the push pins as described in Replacing the push pins and retaining rings.

3. Investigate the old actuator, and select a similar actuator to replace it with. Some lifts do not have encoders on all actuators so the setup after service has to be exactly the same as before. In the picture below, the left actuator has an encoder, and the right actuator does not.

   

4. Disconnect the cables to the selected actuator, and replace it with a new actuator. Note which connector each cable connects to. You must reconnect all of the cables to the same connectors as the old actuator.

   • If the actuator is placed in the side with the lift controller, it might be connected directly to the lift controller. Note down what terminals it is connected to before removing it.

   • To unlock the terminals, use a small flat-head screwdriver to loosen the screw.

   • The wires on each actuator should also be labeled according to the terminals they connect to on the lift controller.

     

Checking the lift controller board

The lift controller board is the green PCB board in the lift. Check that all of the wires are securely fastened to the board by gently pulling on them with maximum 10 N. If any of the wires in the screw terminals are loose, push the wire back in place, and tighten the screw.

Replacing the glide bearings

There are six bolts in each end of each lifting device. Around each pivot bolt there is a sleeve bearing, which must be replaced every 60 000 cycles. The pivot bolts are replaced every 120 000 cycles.

The pivot bolts are locked in place with Loctite. Use a large tool with a Hex head to break the bolts loose.

1. Remove the pivot bolts fastening the lid mount. Use a piece of wood to lock the lid mount in place, preventing it from rotating.

   Keep the bolts if you are using a 60 000 cycle service kit.

   

2. Remove the pivot bolts fastening the entire assembly to the lift housing. Place the Hex key as shown, and place a hand on the POM glider to prevent the assembly from snapping upwards.

   If you have not already applied a new layer of grease on the POM glider, wipe away the grease on the glider.

   Keep the bolts if you are using a 60 000 cycle service kit.

   

3. Place a piece of wood or similar right beneath the joint between the actuator and lifting assembly as shown below. This exposes the last bolt on each side. It might be necessary to place a hand on top of the POM glider to make sure the pieces stay in place while loosening the bolt.

   Keep the bolts if you are using a 60 000 cycle service kit.

   

4. The pivot bearings under each pivot bolt should be replaced along with the pivot bolt. Use a flat-head screwdriver on the inside of the bearing, and gently hammer it out, evenly distributed around the bearings' sides. There are six bearings in each end of each lift.

   

5. With the same method, remove the four remaining bearings.

   

6. Brush each bearing socket off afterward to clean away debris from the bolts and bearings.

7. Replace the two first bearings that were removed by hammering the new bearings gently in to the holes. Push them in from the inside of the lift casing.

   

8. Replace the four remaining bearings by manually pushing them in and squeezing them in place with a pipe wrench or similar. Push the bearings completely into place.

    

9. If you are also replacing the push pins or actuators, do this before reassembling the lift assembly—see Replacing the push pins and retaining rings or Replacing the actuators.

10. If you are using a 60 000 kit, clean the pivot bolts with a steel brush or similar to remove threadlocking adhesive residue. If you are using a 120 000 kit, the kit includes new pivot bolts, and you should discard the old bolts.

11. Apply Loctite 2700 or similar threadlocking adhesive to the pivot bolts and use them to reassemble the lift assembly. Tighten all of the bolts to 45 Nm.

Loctite and many other threadlocking adhesives are toxic substances that can cause skin, eye, throat, or digestive tract irritation to personnel upon contact, inhalation, or ingestion.

• Read the safety data sheet for the adhesive product before applying it.

• Avoid direct contact with the adhesive.

• Apply the adhesive in a well-ventilated area.

Replacing the push pins and retaining rings

There are two push pins on each actuator. One long and one short. Both are fastened with two retainer rings.

1. Place a small piece of wood or similar underneath the joint to free up your hands for releasing the push pins.

   

2. Remove the push pins.

   1. Use a set of retainer ring pliers to remove the two retaining rings from the long push pin

      

   2. With a hammer and a flat-head screwdriver, gently knock out the long push pin.

      

   3. Repeat the process for the short push pin at the opposite end of the actuator.

   Removing the lifting assembly and the actuator from the lift housing provides a good opportunity to vacuum the lift. Remove any debris that might cause wear and malfunctions in the future.

3. Replace the push pins.

   1. Place the actuator in place. Place the short push pin in the slot closest to the center of the lift and apply the retainer rings.

   2. Repeat the process for the long push pin. It might need some force to be moved all the way in. Make sure the retaining ring on the long push pin is on the outside of the lifting assembly, limiting its horizontal movement.

      

Replacing the tension plates

Replace the tension plates. Reuse the same two screws, and tighten them to 25 Nm.

Every 120 000 lift cycles

Replacing the pivot bolts and glide bearings

There are six bolts in each end of each lifting device. Around each pivot bolt there is a sleeve bearing, which must be replaced when replacing the pivot bolts.

The glide bearing are replaced every 60 000 lift cycles. See Replacing the glide bearings for instructions to replace the pivot bolts and glide bearings.

Replacing the POM gliders

1. Remove the screws on each POM glider. Use a 5 mm Hex bit. Keep the glider spacer that is located beneath the POM glider itself.

    

2. Place the new POM glider on the spacer, and fasten it with the screws used to fasten the discarded glider. Tighten the screws to 25 Nm.

   

3. Apply enough grease on the glider to cover the entire surface with a thin layer. The pattern applied by MiR is shown below. One bag of grease should be enough for all four POM gliders.

   If you are going to service other parts of the lift, service those parts before applying the grease.

   

Replacing the support blocks

Push out the six support blocks around the edge of the lift and discard them. You can use a flat-head screwdriver to help remove the blocks.

Replace all blocks with new ones from the kit.

Replacing the anti-slip

Use a heat gun to help loosen the anti-slip. The anti-slip has a pressure-sensitive self-adhesive layer. Remove the old anti-slip and replace it with the new slips.

Finishing up

When you have finished servicing the lifting device, mount it back on the robot by following the appropriate mounting guide. You can find all of the mounting guides on the Support Portal. You can find this guide on MiR Support Portal.

Testing the lifts

To test that the lifts have been serviced correctly, complete the following steps. Make sure the lifts perform as expected in each step.

1. Turn on the robot, and sign in to the robot interface.

2. Go to Setup > I/O modules.

   

3. Under MiR Internal IOs:

   1. Select 0 under outputs, and wait for clicking sounds. This is the initialization of the calibration process.

   2. Select 3 under outputs to raise the lift.

   3. Select 2 under outputs to lower the lift.

If everything works as expected, the lift has been serviced correctly.