FTC Rigid Claw

thingiverse

This is a gripper well suited to pick up blocks for FTC Freight Frenzy. This evolved from the flexible grippers in my Thingiverse account. This is designed to be used with a standard servo. The servo is installed into the motor mount and spool is used to spin wire cables to close the claw, springs are installed to open the claw when the servo spins to open position. Note adjustment screws on spool allow adjusting tension on each claw separately, similar to adjusting guitar strings. Once set epoxy in place, I also place epoxy on wire going into spool hole. Designed for FTC legal servo. Stainless steel cable is used and standard cable crimp sleeves. I used AHANDMAKER 304 Stainless Steel Wire Cable with aluminum crimp sleeve from Amazon. https://smile.amazon.com/gp/product/B08NCWKV87/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Crimps are used at each end of cable for each claw. Screws are adjust and match tension on all four fingers of gripper which was difficult to do with original reference design. Crimps hold tension better than screws of original reference design. Note spool has Gobilda servo horn designed in, so this needs a Gobilda servo or one with similar 25 tooth spline (calibrated printer required to get accurate fit). There is also a spool with no servo horn that allows a servo horn to be mounted. Note that I epoxy the adjustment screws once set to prevent loosening. I use metal wire as the claw hinge threaded through and bent over. See photo. Coat hanger wire works great. File so no sharp edges hit mat, I epoxy over the wire to the mounting block so there no sharp edges to catch mat. Springs are placed in the two larger holes on the claw and the servo mount housing to open the claw. The claw itself has a built in stop that will limit the opening angle, this helps with adjusting the steel cable length with teh adjustment screws so that they close equally. The springs are used are from Amazon, CREEYA Compression Springs Assortment Kit: https://smile.amazon.com/gp/product/B08KD5Q2P7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Note that two claws are included one is wider allowing less accuracy in lining up claw with block for picking up blocks.