Some 1970s Bally EMs have a hinged glass frame
On some Bally electro-mechanical games of the 1970s the playfield glass sits in a hinged metal frame that lifts up and is held by a swing-up rod, instead of sliding out. The whole frame can also be removed.
Systems
Source: Pinball Machine Care & Maintenance, Bernard B. Kamoroff (Bell Springs Pinball Alley)