Problem with getting a rope to follow drum helix

[pheron_301]

Hello,

I am trying to get a rope to drop of a drum at a given angle and have it follow the helix of the drum.   I have used a coil tool in combination with a revolve but as soon as revolve the rope looses its relationship to the drum helix.  I can use the coil tool to define the wrap angle but I would then need to extrude the rope to follow its path away from the drum and in doing so would also loose the helix relationship.  Here is my model for reference.  How can I create a workflow so that paly around with different wrap angles from perpendicular then extrude?

[davebYYPCU]

Looks to me like you have got it happening, but nothing says what angle you are looking for. (Vertical?)  You have inserted a piece to bring it to 45 relative to the origin.

Without the revolve - Job done?

[wmhazzard]

Are you trying to make the end of the rope fall away depending on the pitch and turns of the coil and update when changed? Here is the way that I would do that. 

[pheron_301]

HI thanks for the reply. It seems that the extension of the rope away from the coil is not following the helix how ever. THis is apparent when you look at the drum head on and the gap between rope disappears when you look at the rope that exits the coil. where as the coil has a slight gap based on the pitch described in the coil procedure. if the rope where following the helix it would have one pitch difference in one revolution length and therefore the gap would be consistent.

[HughesTooling · Accepted solution]

Coil is not very good because the end faces are parallel with the helix axis not the helix angle. Coil is also not really parametric as its position is not something you can fix or update. Edit, another problem is if you have a steep helix angle the profile of the coil is squashed into an ellipse.

You can see in this image the face is parallel with the axis.

Because of this you are better off create a coil from sketches and surfaces.

Using sketches the face is parallel to the helix angle. See attached file.

Mark

[davebYYPCU]

Use Plane on path, and an intersection sketch, for the extruded extensions, and position cuts.

Extrude from the coil face does what your see now.

Might help....

[pheron_301]

I like you solution Mark thanks. I think I may have found a way other then the one you  layout here.  If I use the coil and have user parameter that sets the wrap after 90° that solves my revolve issue. Then I drew a line in 3d sketch to to match the helix angle (although I did this by eye for now!) and use the sweep tool to fill it out.  It  seems to work pretty well and it is defined by some user parameters.  Please critique!