Cable modelling...mating helices?

[ztraina]

I'm doing some cable modelling, a simple wire wrapping around and terminating on a pulley. I'm building the cable "in context", meaning I started an assembly consisting only of the pulley, and I'm modelling the cable around it. I've finished the termination, now I'm working on the wrap, which is a helix.

I'm having trouble mating the helix. I want the helix to be coincident with a point on the pulley, so that as the pulley rotates so does the starting angle of the helix. I haven't found a way to do this, and I've been forced to use a design table to manually input a new starting angle when the pulley moves. It seems like the helix is defined in terms of the global reference frame, and there's no way to anchor it to my pulley.

Please tell me there's a better way to mate helices!

 

[CorBlimeyLimey]

Having trouble visualizing this. Do you mean like a winch, where, as the load is pulled nearer, the cables tangent angle changes? If so, then it's not so much "mating the helix" to the pulley, but having a variable start point.
Can you post a picture to a website for viewing?


CorBlimeyLimey
Barrie, Ontario
faq559-863

 

[TheTick]

You need to add some reference features (planes and axes). Add an axis for the helix centerline. The way I usually do this is using the point and sketch plane of the helix's diameter sketch. Then, make a plane through the axis and the helix endpoint. Mate the axis coincident with the pulley axis, and adjust the angle with the plane using parallel or angle mate.

When making helical sweeps, I don't use the helix curve itself for the sweep. I copy the helix in a 3D sketch using "Convert Entities". For some reason, once a helix is used in a sweep, its endpoints become unavailable for picking.

Refer to the example in my previous post.

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