We are aware of a lot of mechanisms around us, but do you know what is a developable mechanism? A developable mechanism is a mechanism that, at some point in its motion, conforms to a developable surface. In other words, it is a device that can move and that is shaped to match a curved surface in a certain position.

To allow motion, the mechanism’s joint axes (where the pin joints are) must be along the ruling lines on the developable surface. Developable mechanisms are possible on all types of developable surfaces. Below is an animation showing developable mechanisms on cylindrical, conical, and tangent developed surfaces.

Advantages of Developable Mechanisms

1. Developable mechanisms are useful because they can be compactly stored and they can exhibit predictable motion. This means we can mathematically model and plan their movement.

2. They can be contained within (or placed on) developable surfaces. Developable surfaces are very common in engineering applications, but currently those surfaces are static and don’t move.

3. Developable mechanisms can give increased functionality to common surfaces and can be compactly stored when not in use.

Challenges of Developable Mechanisms

1. Traditional mechanism design assumes that the shape of the links does not matter. But for developable mechanisms, the shape of the links does matter because the links must conform to the developable surface.

2. Another challenge is where the joint axes can be placed. The joint axes must be coincident with the ruling lines on the developable surface.

Contact the experts at CMDE Labs to know more about the developable mechanisms.