Key-Type Switch - 2-position with locking transfer and break contacts.
This file was derived from:
 IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (6).svg
IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (11).svg
IEEE 315 Contacts, Switches, Contactors, and Relays Symbols (12).svg
(in English) (1993)  315-1975 - IEEE Standard American National Standard Canadian Standard Graphic Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters), IEEE, p. 62  DOI:  10.1109/IEEESTD.1993.93397. ISBN:  0738109479.
Michel Bakni