The strap is going through the part because it's stiff. How do I make it more flexible like a strap is supposed to be?
I guess one immediate train of thought would have been to make the top part of the 'Y' have a slight curve in it so that it follows both the front-to-back and outward curve of the helmet from where it is fixed, outwards and down to the rim of the helmet. Secondly, the straight legs of the straps could be done in small segments so that they are mated together (similar to a bulldozer track) and therefore flexible.
You get the idea I'm sure.............. Just idea's off the cuff!
If you draw the profile with a style spline, it will be easy to tweak the shape of the strap -
I did it with surfaces, and finished with a thicken, but it could be done with solids -
If you need to make adjustments, just edit the profile sketch.
Will that make it harder when I make the drawing? Or are straps for a helmet usually purchased, not manufactured?
I would recommend sourcing/purchasing the straps from another manufacturer.
(It would all depend on what "your company" makes - If you worked for a company that only made helmets, they may or may not have the equipment to make the straps.)
Just another fun part that you will experience in the "real world" - every company has different capabilities.
I'll plan on having the straps purchased because it would make sense in real life and its less work for me to not do a drawing.
I imagine that the details of the strap's dimensions would be discovered by making prototypes. The initial prototypes may be very simple, and make with ribbon and tape. Then, a much more accurate prototype should be made by using material more like the finished trap.
Things that must conform to the human body are difficult to model precisely in a CAD system. And of course, God made people so they had all sorts of variability. So, you test your prototype on multiple people. I don't think it is as simple as bigger people need a longer strap. The lengths of the "Y" legs, and the attachment on the helmet may also need to be evaluated. I am sure there are a bunch of variables that I haven't imagined in my speculation. Real-world building of that strap is sure to be critical, and depends upon the experience and skill of the designer.
So, I would just consider your CAD model of the strap to just be a rough approximation. The CAD model is probably only useful as an illustration.
Will this make it easier to mate with the helmet?
It depends on if the vendor of the straps has a SOLIDWORKS model available to download, and how well it was modeled.
If you aren't able to download a model, you will need to create it yourself to match their spec's.
At that point you can model it however you want to make it easier to work in your assembly.
I'm modeling the helmet and straps
How did you do it with a 2d sketch? I thought that would need to be 3d. I made straps with style splines and they won't move on the axis you moved them on.
I did it with a 2D sketch, but they will only have the shape of the profile in my first picture - they won't "curve" to the helmet.
You could do that with additional profiles or a 3D sketch if you want it to have a more complex shape.
This was just a quick example to show that you could extrude a "wavy" profile, and cut away material to leave the strap.
What is your intent here? If you're doing this as practice or for an assignment then a 3D in-context sketch seems like it would be the best way to get realistic contours as mentioned by other posters above. If you're trying to model for a new design then I would suggest having a good hands-on look at current helmet technology. The problems of conforming to different head shapes/sizes has for the most part been overcome and the designs are fairly advanced with multiple simple-to-use adjustment mechanisms. More advanced designs have incorporated shear mechanisms to reduce oblique impact head trauma. Worth a trip to a higher-end bike shop to have a look at whats currently out there
I was planning on researching helmet standards and doing a few simulations to test the helmet, but I'm not focusing on that. I just want to attach the straps to the helmet.
roger that Eric. 3D in-context sketch (perhaps more than one) from the assembly utilizing splines with wise choice of coincident relations and constraints would be my suggestion. If you havent done much of this type of design work (in-context and 3d sketch) you might want to start out with something much simpler - this looks really interesting but it could become very frustrating very quickly without proper constraints and relations.
Good example of what I was mentioning re: adjustability and MIPS standard. Pretty amazing piece of 'simple' tech
Shannon Scott wrote: Good example of what I was mentioning re: adjustability and MIPS standard. Pretty amazing piece of 'simple' tech
Shannon Scott wrote:
Troy Lee Designs does make really nice stuff, and I should probably get a new helmet sometime soon - might have to look into this one!
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