There are several of them and of different types. One of them is a CHERRY E34. Do a Google search on this and you'll find it.
Another one is a G62, do a search on Cherry G62. This one is pretty standard and can probably replaced with a microswitch from a microwave oven or any appliance that has electrical safety switches.
You can have a look at
this catalog, for instance.
Do you want to replace them all? There are two of the switches that are ganged (stacked) together.
I have a series of pics that show them.