Compact Hitch Using Hinges

Simple hitch design that could be used to attach a trailer to a bike. Good for trailer applications where rotation is not needed or not desired, such as when teaching your child how to ride a bike.

Step 1: Not Ideal

It's easy enough to attach hinges to a large L-bracket, but you end up with twisting forces which may not be ideal for your application. With a few saw cuts you can create a better assembly.

Step 2: Materials

(2) Hinges

(2-4) Short L-brackets

Screws, Nuts (and Lock Washers)

Metal Saw

Step 3: Saw a Slot in Each Hinge

My hinge was slightly thick than my saw blade, so I added a 2nd blade to create a wider cut.

Step 4: Slide Hinges Together

For those without welding skills and equipment (including myself), continue to the next step.

Step 5: Attach L-brackets

Attach L-brackets. Depending on the range of motion needed, you can trim the corners to create more clearance.

Note: I tried replacing the L-brackets with a hinge to create a 3rd axis, but the assembly was too unstable. It would be interesting to see how a welded version with 3 hinges would perform.

If you need rotation, there are also several Instructables on how to add a quick release hose fitting.

Safety Note: Since the hinge pins do not intersect, the assembly should NOT be used for rotational applications - it is NOT a universal joint.

Comments

[openproducts]

Nice approach, thanks for sharing. For a similar purpose I once tested a different approach, which has been documented here:

https://www.instructables.com/id/Failed-Project-Tow-Childs-Bicycle (August 2013)

[MistaKD]

Simple, useful, awesome.

[tomatoskins]

This is a cool idea! How much weight would you suppose that this could hold?

[Coengineer]

Hard to estimate given that these are generic hinges. Some ways to maximize strength: 1) Slotting weakens the flange, so use at least 2 L-brackets in an X pattern to reinforce all sides, 2) Consider stainless steel to minimize corrosion, 3) If welding or using a grinder to cut slot, avoid overheating which can anneal the metal. Also, remove the pin first., 4) Look for hinges where the rolled body does not have a large gap (pin could get forced out), and lastly, 5) Use as big and as long a hinge as your application will allow. One hinge can be longer than the other as long as hole spacing is the same.