EDUCATED ACME NUT

[RIMSPOKE]

A FRIEND WHO OUTFITS PEOPLE FOR PROSTHETIC LIMBS HAS SOME SPECIALIZED EQUIPMENT .

ONE OF THE TOOLS HE USES IS A SUPPORT THAT ALLOWS HIS PATIENTS TO STAND ON ONE LEG
WHILE HE WORKS ON THE OTHER .

THIS HAS A NARROW BICYCLE SEAT MOUNTED ON A STAND . IT NEEDS TO BE HEIGHT ADJUSTABLE
FOR DIFFERENT SIZE PEOPLE .SO IT HAS A 1" ACME THREADED SHAFT .

THE PROFESSIONALLY AVAILABLE DEVICE THEY SOLD HIM HAD A NUT WITH WINGS ,
THIS WAS NICELY MADE BUT REQUIRED HIM TO SPIN IT UP AN DOWN THE SHAFT
WHILE THE WINGS WOULD HIT THE PATIENT's LEGS .

MY TAKE ON THIS WAS TO MAKE A LARGE SIDE EDUCATED NUT LIKE WE USE FOR A QUILL STOP
ON OUR MILLING MACHINES .

HE GAVE ME THE NUT AND SHAFT TO PLAY WITH AND THIS IS WHAT I CAME UP WITH .

PRESS THE BUTTON AND THE THREADS DISENGAGE . THE KNURLS MAKE IT EASY TO
FINE ADJUST UNDER A LOAD . I ALSO HAVE A THRUST BEARING UNDER IT .

SO HERE GOES , HE WILL BE TAKING IT TO THE LEG SHOP TOMORROW FOR A TEST DRIVE .

 

[vocatexas]

Very clever and beautiful machine work as well. Well done!

 

[Asm109]

Beautiful work and a very clever idea. Did you test it to see how much load the nut can take? Probably not a problem but you are making something for human use where they are trusting it not to fail.

 

[RIMSPOKE]

Beautiful work and a very clever idea. Did you test it to see how much load the nut can take?

THE INTERNAL TENSION IS ADJUSTABLE .

THE NUT STARTED OUT AS AN ACME HEX NUT .
I TURNED THE OD DOWN TO 1.500" . I THEN CHUCKED IT ON MY ECCENTRIC CHUCK AND BORED A 1" HOLE .200 OFF CENTER .
THIS CLEANED UP THE THREADS COMPLETELY ON ONE SIDE BU LEFT THEM INTACT ON THE OTHER .

A 1/4" SLOT WAS MILLED ON THE REMAINING THREAD SIDE SO WHEN IT IS ASSEMBLED , I CAN COMPRESS
1 , 2 OR 3 SPRINGS INTO THE SLOT . THIS GIVES THE THREAD ENGAGEMENT A PRETTY HEFTY PUSH
AND WILL CERTAINLY HOLD HUNDREDS OF POUNDS BUT STILL SPINS FREELY ON THE SHAFT .

IF FRANK DECIDES THE EFFORT TO DISENGAGE THE THREADS IS TOO GREAT , HE CAN TAKE IT APART
AND REMOVE ONE OR TWO SPRINGS . HE CAN ALSO INSTALL SOME STIFFER SPRINGS .
THAT BEING SAID , I THINK HE WILL PROBABLY USE IT LIKE IT IS .

HE PICKED IT UP THIS MORNING AND WILL BE TRYING IT OUT THIS WEEK .