How are engines mounted onto wings?
On Sunday 4 October 1992, El Al Flight 1862 crashed into a suburb of Amsterdam after the right inboard engine separated from the wing and took part of the wing and the right outboard engine with it. 

The separation was caused by fatigue fracture of the fuse-pins that connect the engine to the aircraft. The engines of the Boeing 747-200 are joined to the wing by four fuse-pins. 

In the investigation report you can find detailed information about the construction that mounts the engine to the wing. Especially sections 1.6.3, 1.6.4 and 1.16 are of interest to you, although I recommend reading the entire report if you have the time. 



Source: Raad voor de Luchtvaart, document AAR 92-11



Source: Raad voor de Luchtvaart, document AAR 92-11