Introduction: The Claw.
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
glue
a drill
a servo
4 x 4mm bolt
4 x 4mm nut
Attachments
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.
http://www.youtube.com/watch?v=-R7vCUfmeNU
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
Participated in the
3rd Epilog Challenge
Participated in the
MakerBot Challenge
41 Comments
12 years ago on Introduction
hey could i use a dremel
Reply 12 years ago on Introduction
So could I...
Reply 12 years ago on Introduction
so i can just use my dremel
Reply 8 years ago on Introduction
Don't let a completed Claw get hold of your Dremel! It will use it to build an army of Claws!
(For the same reason, don't let your Claw into a hardware store!)
8 years ago on Introduction
I really like the design.
I'll reproduce a tiny one but with a stepper motor and a screw instead of the cables.
12 years ago on Introduction
I made a claw using three one time but they were set with a two-one configuration, not circular like this. I used rubber bands instead of springs but have another thought. What about two wheels connected to the servo, feeding wire as in your plan, closing the claw, and the other feeding the opposite way to where the springs are attached? This would make the open and close completely dependent on the servo and no need for the springs.
Reply 12 years ago on Introduction
I thought about rubber bands, but decded springs were probably better. Also, I came up with your idea about wires pulling both ways myself, but it was simpler to build using springs. Thanks for the feedback though!!
Reply 11 years ago on Introduction
The springs are a much better idea. After about three days of playing with the design we had to replace the bands because the snapped. Let me tell you about the pain my hand went through while fine tuning everything...
11 years ago on Introduction
i saw your claws and arm with wrist on youtube and i just have to say they are great. im just wondering if you have this in a CAD file that i could use?? im trying to make the claw cuz it looks awesome.
Reply 11 years ago on Introduction
I can't release the files for the wrist and arm, because they are part of my IGCSE project, and the exam board might get funny. The file for the Claw above, though, is attached.
12 years ago on Introduction
The whole assembly is about 20cm long. If there is a better filetype for you, just ask and I will send it to you. If you want to edit DXFs, then i can recommend QCAD or Draftsight. Please send me a photo if you make one.
12 years ago on Introduction
Very nice, this could be quite useful in some evil world domination robot! You should post the drawings to thingverse too...
Reply 12 years ago on Introduction
its a dalek claw isn't it?
Reply 12 years ago on Introduction
I thought the Dalek's had a toilet plunger, not a claw...
But still, it is an excellent addition.
Reply 12 years ago on Introduction
They only had a toilet plunger because the BBC couldn't afford grippers..
Reply 12 years ago on Introduction
You wouldn't say that to a Dalek's face...
Reply 12 years ago on Introduction
Not if I get all Bad Wolf up in its, uh, eyestalk thing.
Reply 12 years ago on Introduction
some daleks have plungers others have claws, flamethrowers, extra weaponry and assorted other tools depending on their assignment.
Reply 12 years ago on Introduction
That is the eventual plan! I will be using this as part of my GCSE project for tech, the project is technically a teaching aid, but ...
12 years ago on Introduction
The Craw!