Trailer lock

A trailer lock, comprising:

• a lock bar;
• a cylinder connected with the lock bar, the cylinder comprising an outer casing;
• and
• a plug casing mounted at a front end of the outer casing and a plug provided in a middle of the plug casing, wherein
• the cylinder further comprises a bolt casing fixed in the outer casing and a cam accommodated in the bolt casing and connected with the plug;
• a telescopic core is provided in the cam, telescopic bolts for fixing the lock bar are provided at two sides of the bolt casing, the bolt has a front end connected with a rear end of the cam, and
• the lock bar has a front end provided with a press head having an annular neck where the bolt is clamped;
• through holes where the bolt is clamped are provided at two sides of a rear end of the bolt casing;
• the bolt is mounted into the bolt casing along the through hole;
• a bump connected with the cam is provided at the front end of the bolt;
• a first spring is provided between the bolt and the outer casing;
• an accommodating hole is provided at an outer side of the bolt;
• and the first spring extends into the accommodating hole and has an outer end pressed against an inner wall of the outer casing;
• the cam has a front end provided with an insertion hole where a rear end of the plug is inserted;
• an accommodating groove is formed at the rear end of the cam;
• a second spring is mounted in the accommodating groove and has a rear end connected with the telescopic core;
• and a rotating block, provided at the rear end of the cam, is abutted against an inner side of the bump;
• and
• a channel is formed between the two bolts and has a large rear-end opening and a small front-end opening;
• a through hole is provided at a rear end of the outer casing;
• the press head sequentially penetrates through the through hole and the channel, pushes the bolt away to extend into the accommodating groove of the cam, and is then pressed against the telescopic core;
• and an inner end of the bolt is clamped into the neck of the press head.