Hydraulic heads for injection pumps and the injection pumps themselves

A hydraulic head for a fuel injection pump including a casing defining a housing and a support surface, said head comprising:

• a cylinder defining a pump chamber and including at least one fuel supply orifice formed in the cylindrical side wall thereof, a pump piston disposed for movement within the cylinder, a delivery connector connected to the cylinder, said delivery connector including an external shoulder which cooperates with the support surface of the pump casing to provide an axial stop for the hydraulic head, said delivery connector further including an internal delivery valve and a depending housing having a threaded inner surface, the end portion of the cylinder facing the delivery connector being received in said housing of said delivery connector and including complementary threaded outer surface which engages the threaded inner surface of said housing so that, in the fully assembled hydraulic head, said cylinder is directly suspended from the delivery connector, said delivery connector also including an internal shoulder and said delivery valve of said delivery connector including an outer collar which is clamped between the end wall of the end portion of the cylinder adjacent to the delivery connector and said inner shoulder of the delivery connector.