MeArm (IV) – Mechanical structure II

mearm_box_finished

Now let’s go with the second and final part of the mechanical structure of the MeArm. Remember that I’m building version V0.4 of the robotic arm and following the steps of this instructable from the creator to assemble every part of the arm.

Attach together both servos

MeArm: servos together in the 'cage'
MeArm: servos together in the ‘cage’

We have tested both servos at the end of the previous post so now we have to attach them together in a sort of cage that is the center of the robot. In this step you may feel like you need more hands than you have but I found that the assemble is easier if you first put together all the parts (no screws), then you place one nut in its position (it should get properly fixed) and finally tighten the screw. Don’t worry about taking your time in assembling this part because is probably the most complex part and also, once you finish the full assembly of the robot and you start to test the movement, this is the part you will check more often.

Now attach the cage to the base

MeArm: left and right hand servos attached to the base
MeArm: left and right hand servos attached to the base

This step is easy… more or less. The theory is quite easy but reaching the screw may be difficult, it usually helps if you loosen all the screws of the cage (at least the ones on the back side to allow the center plastic plat to move slightly to one side. Again, be careful not to over-tighten the screw to the servo or you may damage the servo.

Complete the top part of the arm

MeArm: Finished arm before attaching the claw
MeArm: Finished arm before attaching the claw

Once you finished previous steps, the easiest parts come now. The top size is straightforward if you keep in mind that everything should fit nicely. If you find yourself forcing any part, check again because you are probably missing a part (and this part is probably a spacer).

Building the claw with the last servo

MeArm: finished claw.
MeArm: finished claw.

Although it looks very complex, the claw is quite easy to build: assemble all the parts carefully and test that they can move freely before tighten too much the screws. Before attaching the servo, check that it is near of the center og its range of motion. If you do this, you won’t have any problem to open and close the claw with the servo later.

Finally, attach the claw to the arm and the MeArm is complete!

MeArm: finished, ready to start to move.
MeArm: finished, ready to start to move.

Attach the three last screws and you are all set. Your new robotic arm is ready to be tested and programmed.

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