Adjustable hinged door closer

An adjustable hinged door closer, comprising:

• a seat with a hollow space, said hollow space having a hydraulic chamber, an actuating groove, first and second cylinders in parallel formed therein, the actuating groove and the first and second cylinders being arranged separately at both ends of the hydraulic chamber, the first and second cylinders being provided with an end, the first cylinder having an end with a first end cover screwed onto said end of the first cylinder, the second cylinder having an end with a second end cover screwed onto said end of the second cylinder;
• a connecting duct, arranged between the first and second cylinders and connected to the first and second cylinders;
• a throttle valve, placed on a connecting duct, regulating hydraulic pressure;
• a connecting seat, assembled within the actuating groove of the seat in a swinging state;
• a pivot protruded from a center of the connecting seat;
• a first elastic linkage unit, containing a first connecting rod, a first spring and a first piston, the first connecting rod having an interior linked to the connecting seat;
• and an exterior linked to the first end cover, said first spring being sleeved onto a periphery of the first connecting rod, first piston being installed close to the exterior of the first connecting rod;
• and located within the first cylinder of the seat, said first piston having a circular retaining surface and a hollow cylinder, said hollow cylinder having a tank formed within the hollow cylinder and internally provided with a tapped hole;
• a second elastic linkage unit, containing a second connecting rod, a second spring and a second piston, the second connecting rod having an interior linked to the connecting seat, the second spring being sleeved onto a periphery of the second connecting rod, said second piston being installed at the exterior of the second connecting rod and located within the second cylinder of the seat, the second piston being arranged at intervals correspondingly to the second end cover;
• a double-threaded regulator, incorporated onto the first connecting rod of the first elastic linkage unit, said double-threaded regulator comprising a double-threaded column, being connected to the interior of the first connecting rod and being provided with a double-thread shifting to two thread pitches by one rotation, an end of the double-threaded column having two threaded cutting portions and being screwed with the tapped hole set within the tank of the first piston;
• and
• a rotating lever, assembled into the tank of the hollow cylinder of the first piston, a straight groove and bulge being embedded between the rotating lever and the tank, the rotating lever driving the first piston to rotate simultaneously, the rotating lever having a tool driving portion penetrating the first end cover set externally onto the rotating lever, the first spring having an external diameter is bigger than an external diameter of the second spring.