deskthority

I have been wondering about switches whose tactile event is due to the way the switch is actuated. Are there any old switches that have a curved vertical leaf spring that snaps side-to-side between two bistable positions?

I am thinking something like this:


The leaf spring (leafy green) is squashed between the upper and lower housing (purple) so it curves. It can be pushed so the curve snaps to the left or right.

When the switch is at rest (as pictured) the leaf spring curves to the right. When actuated, it snaps to the left and touches the contact (coppery yellow) to close the circuit.

The slider (blue) has a coil spring (not in the diagram) to provide return force. Two D-shaped projections on the slider push the leaf spring right or left as the slider is pushed or released.

I can think of a lot of reasons this might not work well in practice…

Yep! What you're describing is essentially a plate spring. Iirc there is just one where it is vertical, Alps SKFF. A teardown can be seen here. It's a bit different as it is using a lever rather than pushing directly on the plate spring.

Plate springs are much more common horizontally, with Futaba MA, Clicky FLS, beam spring and Alps SKCP probably being the most well known.

Most plate springs "unbuckle" when no external force is applied, where beam spring is the only mentioned plate spring that needs help to change state by other parts of the switch.

There is one modern switch utilizing a plate spring, the NovelKeys Cream Clickie. However, the plate spring only acts as a clicker and is not directly tied to actuation, which is a bit unfortunate.

Aha, I thought there must be something like it already, thanks!