Not quite model engineering, but please bare with me....
I'm in the process of building a myself a single sided post lift for a
motorcycle - just at the testing phase. It is almost complete, working
and I have done a quick test of it.
Basically it is an L shaped fixed main frame, an H shape under the bike
to keep the L vertical - with a sliding section attached to a main
horizontal lifting beam. Attached to the later are a couple of forks
enabling the whole thing to be slid under the bikes wheels to then
raise it by cranking the sliding part up the main vertical post. This
all made from welded box section steel.
The actual lifting is done by means of an ordinary mild steel threaded
rod with a captive nut under the slider and a welded nut on top. Turn
the rod and up it goes, the rod being under tension from a bracket at
the top of the post. The OD of the rod is approximately 20mm, weight of
bike plus lifting system about 250kg and the distance it raises it from
the ground to a maximum of 30".
It works, but involves quite a lot of effort cranking the rod around to
raise it the 30". I have not fitted any sort of bearing under the top
nut, just a couple of washers and liberal amount of grease. It has been
suggested that a square thread would be much less effort, rather than
the V thread I am having to use at the moment. Is that correct?
If it is correct, where could I source a (cheap) length of square
threaded rod plus a pair of matching nuts, able to fit through a 20mm
hole with a length of around 32"?
I know hydraulics would be much easier, but it has to work from almost
ground level up to its maximum height - not even space to get a car
trolley jack in.
- posted 15 years ago