This spoke actuator switch is used to detect a transient target and remember its position.
The target passes through the spoke rotating the spoke by a quarter turn. This toggles the switch, normally a closed circuit, from ON to OFF. If another target transitions through the spoke, it will again toggle the switch this time from OFF to ON. Alternatively, the target can return back through the spoke again toggling the switch from OFF to ON. The spoke once rotated will maintain its position until it is moved to a new section - this is unlike normal limit switch actuation which normally will want to return to its rest position - with this switch there are 4 rest positions at each 90° points in a 360° rotation.
The tip over point is at 60° at which point the spoke will rotate to the next segment position.

EN60947-5-1, IEC947-5-1

UL, CSA