Designing Interlocking Chain Links for a Swing Set Using Sketches, Sweeps, and Body Patterns in CAD

Hello, in this video we're going to create the chain for our swing set. If you look over here to the left, this is more or less how it's going to look. If we zoom in, it's going to be the repeated set of these two bodies.

One chain that connects to the wire and another one that's perpendicular to it,  and that will be one instance of a pattern that we're going to create. So let's do that now. We'll close this out.

All right, now because our wire ended on a flat surface,  we have a plane off of which we can create a sketch. So let's highlight this surface here, go to sketch, so we can begin our chain. The first thing I want to do is highlight that same surface and just convert the entities.

Then I'll highlight the circle itself and make four construction. All right, as we know, the shape of a chain is a slot shape,  and we happen to have a slot sketch tool in our sketches tab here. There's actually a drop-down menu which shows multiple types of slots,  both curved and straight, that can be made in different ways.

For this particular feature, we're going to go with the very top one, straight slot. Now a straight slot, you'll need three clicks. The first establishes the center of one of the circles of the slot.

The second establishes the center of the next circle of the slot. Go ahead and do that now with a vertical line. Or rather two clicks, well, three clicks.

And the third click establishes the width of that slot. For right now, let's just go ahead and make it arbitrary and set it about here. Hit escape to close out that command.

Now we're going to use this pathway and a swept boss base to make the slot,  but I want to make sure that it's going to hug the inside of this wire perfectly. So let's kind of mock that out using offset entities. We'll go to offset entities, highlight this path, set it to bi-directional.

And then it's going to establish for us a thickness of this chain,  in which case I want it to be a total of a quarter inch thick. We're going to offset an eighth on either side. Close that out.

I'm just going to make sure that this distance is indeed a quarter inch. And it is. Now we have a lot of solid lines here and we don't want them all to be solid.

So let's grab the inside slot, all four lines, make that for construction. And then the outside slot, the other offset, let's make that for construction as well. Great.

We can adjust the size of this slot inside and outside. But let's set a tangent relationship between this circle and this inside arc here. There we go.

Now all we need to do is establish the height of this slot. We'll go to smart dimension and use this line,  which sets the inside of both of those circles. And we'll set that to two inches.

Great. Our sketch is fully defined and it is ready for a sweep. We'll go to features, swap to boss base.

And it's recognizing this as a profile. And it would do that because it's a closed sketch entity. It's a good instinct on SOLIDWORKS' part, but it's actually incorrect in this sense.

Let's highlight and delete it out of the profile box. And highlight the path box and select that same line. And just like before, we're not going to create our own profile from scratch.

We're going to use an automatic circular profile and then just set the diameter. In this case, the diameter is going to be a quarter inch. We'll go to options, uncheck merge result.

And then close it out with a green check mark. All right. That's one of two chains that we need to draft.

Let's go ahead and save our work. The second chain is going to be a copy of this one. So let's use move copy bodies.

We'll select this body. And for our first move, let's go ahead and rotate it 90 degrees. We can just grab that disc there and rotate it more or less to 90.

And then we'll finish it off here on the left when we just place 9,0 for 90. And watch it update perfectly. We'll close it out with a green check mark.

Now with this new chain link, we need to move it up. We'll go to move copy bodies again. Uncheck copy because we no longer need to copy that body.

Grab this new body we just created. Start dragging it up with that arrow. Get it just underneath.

There we go. And I can tell that it actually wants to be two and three-eighths inch high to just barely hug that inside. Close it out with a green check mark.

See how it looks. All right. They are hugging each other quite well.

So that was the magic number, 2.375. Let's go ahead and save our work. Now that we have a chain link set, we can pattern this set all the way up to the beam where it attaches. So let's do that now.

Now, before, to pattern a body, we've used a linear pattern. But we can also use move copy bodies. So let's try that.

We'll go to move copy bodies. Select the two bodies that need to be patterned. Select copy.

We'll just go ahead and drag this up to where it needs to be. And I imagine this is 2.375 times two. So I'm going to type that in and see how it looks.

Just about perfect. So 4.75 is that distance that we want. And it's only creating one instance for us.

We actually want several. Well, as soon as we hit copy, it opened up this instance box. And we can add instances and continue the pattern upward until it hits just underneath.

The beam. Now, if we pattern into the beam, we've gone too far. So let's do just below.

Looks like 18 is the number that we want. If we're satisfied with that, close it out with a green check mark. Save your work.

We've created unique bodies. So let's go ahead and highlight those. Right click on green low gloss plastic.

Edit appearance. Now, for this, we actually want to highlight an entire chain link set. So that'll be this link and this link.

And we'll consider that one body. Even though there's two separate bodies, we'll consider it as one. Because we're going to need both for a pattern later in the assembly phase.

We'll close it out with a green check mark. Save our work again. And that's it for this video.

In the next video, we're going to create the hook or ring that holds the chain. And finish out our swing set.