Is that a steamer trunk? Could be a “toggle latch”.
https://www.mossman-trunks.co.uk/32-parts-trunk-fittings?srsltid=AfmBOorNYQRoEJigwEuhJHsfAVnFhX-aP4kl2Yf4SS-xQ-gNMGku5Gg-
It is an old carpenter's tool box, I thought the centre round bit released the sprung catch but it doesn't!
The hinged bit with a hole in it has an over-centre hinge, so it will 'snap' into position over the pimple. Your's may need a little oil in order to achieve this.
@eskay started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Is that a steamer trunk? Could be a “toggle latch”.
https://www.mossman-trunks.co.uk/32-parts-trunk-fittings?srsltid=AfmBOorNYQRoEJigwEuhJHsfAVnFhX-aP4kl2Yf4SS-xQ-gNMGku5Gg-