Disc brake caliper, method for manufacturing a caliper and caliper spring

1. A lost core for the realization by gravity casting of a caliper body, comprising:

a core body intended to obtain the space in the caliper body for housing a pair of pads having friction material adapted to be supported by the caliper body;

intermediate chamber cores comprising a proximal piston chamber core and a distal piston chamber core, wherein each of the intermediate chamber cores project axially from first and second sides of the core body for the realization on each side of a proximal piston chamber and a distal piston chamber; and

a proximal branch core that protrudes from the proximal piston chamber core and extends towards the distal piston chamber core and a distal branch core that protrudes from the distal piston chamber core and extends towards the proximal piston chamber core;

wherein the proximal branch core and the distal branch core terminate with a respective free end separated from each other.

2. The lost core of claim 1 , wherein said proximal branch core and said distal branch core are adapted to form an oil feeding circuit in the caliper body.

3. The lost core of claim 1 , wherein pressure centers for caliper body pistons developed from said intermediate chamber cores and two side chamber cores fall at vertices of an imaginary rhombus for which a minor diagonal is disposed radially and a major diagonal is disposed laterally.

4. The lost core of claim 3 , wherein said minor diagonal intersects said major diagonal of the imaginary rhombus at a midpoint of the imaginary rhombus.

5. The lost core of claim 3 , wherein each of said first and second sides of said core body has a total of only four pressure centers.

6. The lost core of claim 3 , wherein the pressure centers fall within peripheral contours of each pad of the pair of pads.

7. The lost core of claim 4 , wherein said pressure centers are arranged so that said major diagonal extends between said side chamber cores without intersecting with said immediate chamber cores.

8. A lost core for a caliper body, comprising:

a core body to create the caliper body including a pair of pads having friction material adapted to be supported by the caliper body;

first and second intermediate chamber cores comprising a proximal piston chamber core and a distal piston chamber core, wherein the intermediate chamber cores project axially from both first and second sides of the core body to create on each side of a proximal piston chamber and a distal piston chamber for the caliper body, wherein said first and second intermediate chamber cores are the only intermediate chamber cores; and

a proximal branch core that protrudes from the proximal piston chamber core and extends towards the distal piston chamber core and a distal branch core that protrudes from the distal piston chamber core and extends towards the proximal piston chamber core;

wherein the proximal branch core and the distal branch core terminate with a respective free end separated from each other;

wherein centers of said cores are arranged at vertices of an imaginary rhombus for which a minor diagonal is disposed radially and a major diagonal is disposed laterally,

wherein said vertices fall within peripheral contours of each pad of the pair of pads;

wherein vertices are arranged so that said major diagonal extends between two side chamber cores without intersecting with said immediate chamber cores.