Hydraulic leaf spring spreader

We are now on the third version of adaptations to use my pre-existing 10-ton body repair press as a leaf spring spreader for use on Dean's emerging hot rot.

This latest version has an adjustable length. This solves the issue that none of the combinations of tubes supplied with the 10-ton strong arm were quite the right length to get the spring eye's where we needed them. Prior to this, full extension was not quite enough but we could not get the next longer tubes in between the eyes when under no compression!

I turned up an adapter to slide into the strong arm tubes. This is simply to keep the M24 threaded bar central. A nut at the interface and flat faces for a spanner on the threaded bar allow the length to be adjusted, even under load.

Worked but not ideal

Our first attempt used a combination of whatever we had to hand to deal with the reverse eye on the spring. This did not always work out. The picture shows the lifting shackles overhanging the holes that we need to get the spring mounting shackles into!

The second version used some plates to push against. They avoided anything obstructing access to the spring shackle mountings. Although these brackets worked, and still do, the plates and the M12 bolts bent significantly.

The current version works well and it is relatively easy to fit and remove the spring. If I make another version it will be to strengthen the brackets that are used to push on the spring eyes.

Scientifically tested :-)

To get the tension right, the spring has been on and off the car a few times. Using the best measuring techniques we have to hand, it now feels about right :-)

==

Rope with Fusion 360

When finding out how to represent a rope in Fusion 360 I looked up 'coil following a path' this, it turns out, has a name, 'Helical Sweep.' It is more commonly used for curved springs.

Creating the rope is two helical sweeps at 180 degrees rotation to each other.

I found a pretty good video to show me how to create a single helical sweep:
https://www.youtube.com/watch?v=OudriYF_X8Y

There's no point in going in to detail, the above video explains it clearly.

As a reminder, mainly for me, here are the steps:

• Create some parameters to make it easier to adjust. [sweepRadius (mm) 10mm, Revolutions (no units) 5, twistAngle (deg) Revolutions * 360]

In model mode

• Create a path, as a continuous tangent line or curve in a sketch. It will cause an error and fail if it has any awkward kinks from one line segment to the next. I used the 'Tangent Arc' line to make a nice curve.

• Create a 'plane along path.'

• Create a sketch on the plane, just created, with a construction line the length of the sweepRadius of the coil and a normal line of any length but about 10mm worked for this model That normal line following on from the sweepRadius construction line. (I revisited this sketch to create the second coiled strand needed for the rope effect, I just did the same lines mirrored.)

Go to Patch mode.

• Create a sweep following the path, with a twist angle set to the variable twistAngle. That gives a flat helical shape.

• Create another sketch on the front plane, including 3D geometry.

• Select the inner edge of the included 3D geometry to create another path.

• Create another plane along path, selecting that helix. Move the plane to zero on the path.

Back to the model mode

• Create a sketch on that plane, with a shape centred on the start of the point of the path, usually a circle but could be any shape.

• Select the shape and create a sweep along the helical path.

I needed two of these coils intertwined to make a nice looking rope.

I used the same sketch for the sweep radius but created another construction line and normal line in the opposite direction from the centre.
Using the same spiral sweep I created another coil.

I needed to patch the patches and stitch them to make them both solid models. I adjusted the diameter of the strands until they just merged, which was 20mm.

I textured them using 'weathered leather,' as that was the best I could find to match a hemp type rope.

==

For the parameters I ended up with:
sweepRadius = 10mm
Revolutions = 5
This was over a 300mm length of rope.
Each of the two rope strands was 20mm diameter.

==

Links to similar tutorials:
https://www.shapeways.com/blog/archives/37534-holiday-tutorial-creating-celtic-knots-fusion-360.html

==