Has anyone made a laminated composite "Live hinge"?

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Has anyone made a laminated composite "Live hinge"?

Has anyone made a laminated composite "Live hinge"?

Author	Message
cookeaa	cookeaa posted 11 Years Ago HOT Topic Details
Group: Forum Members Posts: 7, Visits: 58	I'm considering a project making a lightweight single wheeled cycle touring trailer, these typically need a horizontal hinge point to accommodate cornering, most simply use a fairly standard bearing/bushing and shaft arrangement of some sort. But it occurred to me I could design some sort of live hinge insert using a laminate of some sort, the advantages being it would save weight and possibly be simpler/easier to manufacture, and if it was done as an insert rather than as part of the trailer's structure it would allow me to replace a worn or broken hinge element more easily... I know some RC aircraft and cars use laminated composite live hinges and I've definantely seen MTBs that use them as part of their suspension systems, so its not a completely novel concept... My real question is what sort of reinforcement, and resins should I use? It would need to allow movement in only one plane of maybe 90 - 120 degrees (45-60* either side), and it would be under pretty much constant tensile loads from towing so I guess most/all of the reinforcement would need to be aligned to that primary load path and tolerate lots of lateral flex. And just how flexible is a "flexible" epoxy? or should I be looking at other resins?
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FLD	FLD posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 2.7K	Maybe I've missed something but what would be wrong with a small section of rope? Its flexible, rotatable, cheap, replacable etc.
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cookeaa	cookeaa posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 7, Visits: 58	FLD (23/07/2014) Maybe I've missed something but what would be wrong with a small section of rope? Its flexible, rotatable, cheap, replacable etc. like I said I want to make a hinge connection a single axis pivot point not a substitute for a universal or ball joint... The trailer will have a single wheel, tow it using a bit of old rope and it will spend most of its time being dragged along on its side.... I already have a 2 wheeled trailer which uses a spring in a similar manner to what you suggest, it simply won't work in this instance... I had envisaged a 100mm long or so laminate with a "Deflection area" maybe 15-20mm wide mounted vertically between the trailer and the towing arm... This illustration for a rubber live hinge shows the principle perfectly: and I could yet look at something off the shelf like this, but I liked the idea of designing my own solution...
	Reply Like 5