Sunday 15 December 2013

California style self rolling roof

Too much reading of Slomove's Birkini, His half hood is more for the California sun than rain protection, however - looked like an interesting concept so, not having much luck with my First hood design, I thought I would try and re-create it.

The concept is to have a hood which can be opened & closed while in the car, utilising a roller spring (roller blind) as the central support to furl and unfurl the roof fabric. No idea if it will work really...

First up the roller blind mechanism, I got one with nylon/plastic ends so they are easily dismantled  & modified - but possibly also slightly weaker? One end free wheels, the other larger end is locked in place & tensions the spring. I don't need the automatic position locking so the ball bearing & associated mechanism can all go:

Paired down the locking end with my Dremel to end up with the hexagonal nut which will slide inside the struts, reduced the height of one brass bush & reduced the internal height of the cage which holds the roll tube - the last part is to expose more of the central pivot shaft:

The locking end now will slide inside the support tube but will stop the shaft rotating. Offerred up the entire end components to check, may need some adjustment but looks ok:

The other end is simpler, this just free wheels; so modified to take an M6 bolt through the centre and will be simply bolted loosely to the other tube: 

Next up I wanted to try improve on Slomove's design a little and put a dog leg bend in the support tubes, this should ensure they don't impact comfort, hitting my shoulder, when the roof is open. A little prototyping with a coat-hanger to get the right shape then on to some 16mm aluminium tubes.

A RhoCar member kindly offered use of his pipe bender, I was impatient though, bought a spring bender and had a go myself. The bends are not perfect & not strictly identical, but will do the job:

When closed the struct sits back along the roll bar & away from the passenger shoulder. When open the top point reaches exactly half way along the roof line:

Few more parts ordered from Ebay & the next task is to work out exactly where the pivot point will be avoiding the internal structure in the side panels & drill some mounting holes. I'm intending to mount with a couple of rivnuts in the side panel and a threaded knob of some sort to make everything removable.

Update - This never worked properly, so I have not used it; its much simpler to create/buy a surrey/half hood simply strung between the roll bar and top of the windscreen.

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