Take a look:rough drawing shows a cutter to cut 3" pieces of flat steel wire, 3 at
a time, every 0.5 seconds. The wire is advanced through the block between
the two shown 3/4" x 3/4" x 1/4" carbide inserts. Notice the notch in the
lower insert. The arm pivots on a 3/4" shaft in 2 Timken bearings in the
bored hole in the block nearest the step. The other bored hole has bearings
for the 1" shaft that has a cam follower with a 5/16" offset to act as an
actuator cam -not shown. The cutter arm also has a 3/4" x 3/4" x 1/4"
carbide insert. As the cam makes the arm pivot the wire is cut and a spring
returns it to the open position.
The part I need thoughts on are how to pre-load the carbides in such a way
that it is easy to unload to change the carbides...(notice I get 8 cutting
edges on each insert!) The lower carbide should last almost forever as it
is not used in cutting and has the guide notch ground into it. I wonder how
much pre-load is needed on the carbides, they will be sliding on each
other's faces. One thought is to have the carbides backed up with a block
of steel that slides in a cut-out in the main block but can be clamped
tightly and have a differential screw apply the loading pressure then clamp
the sliding block. The goal is to be able to change the carbides in a few
minutes and have a positive, easily adjustable and reproducible pre-load.
Oh, by the way, the assembly is not extremely accessible. I figure if the
carbides are real easy to change, they will last a long time and if it takes
an hour, they will need to be changed often...Right?
- posted 16 years ago