This is how to build... The Claw.
The Claw is my awesome 3 fingered robotic gripper. it is controlled with a servo, and can be attached to another servo which acts as a "wrist".
To see what it should look like, there is a video here http://www.youtube.com/watch?v=-R7vCUfmeNU.
(for the NRW contest, I am 15)
Step 1: Laser Cut the Pieces
Below are the DXF designs to laser cut the pieces. It should be fairly self explanatory. If you don't have access to a laser cutter, then the designs are also below.
You will also need:
3 x 3mm bolt
3 x 3mm nylock
some multicore wire
some 3mm dowel
3 small pull springs
4 x 4mm bolt
4 x 4mm nut
Step 2: Assemble the Base
You should have 3 circular baseplates. one of them has two long rectangular slots in, put this to one side. Glue the other two plates together, making sure all the holes line up. I used bolts to make sure the holes were lined up.
Step 3: Add the Jaw Mounts
Glue the 6 smallest pieces into the baseplate, ensuring they are perfectly upright.
Step 4: Mount the Servo Mounts
Bolt the servo into one of the two servo mounts using the 4mm bolts and nuts. Then, turn the baseplates over and glue the two mounts in.
Step 5: Add the Dowels
Cut 6 pieces of 3mm dowel to 50mm long. Insert them through the 6 outer holes on the two baseplates, so the ends are flush with the side opposite the servo. I found that scraping the ends with a pencil sharpener blade ensured a good fit.
Step 6: Add the 3rd Baseplate
Hook the 3 springs over alternate dowels, making sure they are on the ones that sit between pairs of jaw mounts. Then, push the 3rd baseplate onto the dowels.
Step 7: Glue in the "wrist" Mounts
Glue the two "wrist" pieces into the 3rd baseplate.
(Sorry about the lack of picture, I appear to have forgotten to take one.)
Step 8: Add the Jaws
Drill a small hole horizontally into the hole nearest the centre. Also, file into each side of the other hole, so the spring will fit around. Then, feed the end of a piece of wire into the hole, and draw it out the side. Tie a knot in the end, and push it back into the hole. Then, bolt each jaw between the jaw mounts with a bolt and nylock.
Step 9: Finish Off
Bend the end of the spring enough to fit around the edge of the hole, before bending it back into place. Run the 3 jaw wires down the central hole, and tie them throught the holes in the servo head.
Step 10: Enjoy!
This can be mounted on another servo to form a wrist. The servo should pull the wires, which close the jaws. When the servo turns the other way, they should be pulled open by the springs.
Health and Safety:
Warning, claw may become sentient and eat your soul. Also, you may find small children or pets going missing.
Second Prize in the
National Robotics Week Robot Contest