What is the launching principle of Type 89 50mm Grenade catapult?

When the weapon is ready to impact, the hook of the living body blocks the annular groove at the lower end of the striker, pulling the sliding sleeve downwards, driving the living body downwards through the safety pin, driving the striker downwards, and the spring of the striker begins to compress, and the sliding sleeve continues to slide downwards; The firing machine touches the release mechanism to release the striker, and the striker moves upward under the action of the striker spring. After the ejector pin moves in place, under the action of inertia, the striker continues to move upwards and hits the primer of the Grenade, thus completing the firing process.