The method of manufacturing sealed hollow male elements for hinge devices comprises the steps of shearing a segment off a drawn rod, and successively causing the material to flow laterally upwards such as by cold impact extrusion by means of a punch, to form a hollow body (5) of constant cross section having an open end. Thereafter, there is performed on said hollow body (5), as by impact with a die, a reduction of one portion at the open end (14), thus defining a hollow pin (8) having an open end (14). The latter is then stopped by press fitting a shaped body (13) thereinto.

57 The hinge device (1) comprises a male element (2) and a female element (3). The male element (2) includes a cylindrical body (4), wherefrom protrudes a pin (5), having a smaller diameter than the cylindrical body (4) and lying coaxial therewith. A seat is provided at the end of the pin (5), and a sphere (10) is maintained in the seat. The female element (3) is shaped to accommodate at least part of the pin (5). Both the male element (2) and the female element (3) are associable with casings.

A method for the manufacture of vehicle hinges produces, by blanking and cold-forming, hinges (11, 15) of the type comprising two flat rectangular plates (7, 9) each provided on one side with a flat projection (12, 16) of the same thickness as that of the plate (7, 9) terminating with a substantially cylindrical enlargement (13, 19) traversed by an axial hole (14,18) for receiving the hinge pin of the hinge (11, 15). In particular, the method according to the invention is usable for the manufacture of hinges (11, 15) of the type in which the axis of the said hole (14, 18) is offset with respect to the plane of the associated plate (7, 9). The invention also relates to a press tool usable in a press to effect the cold-forming operation which constitutes a stage in the manufacturing method of the hinge.

Provided is a method of manufacturing an automobile door hinge having high strength from a round steel bar at low cost through a process including hot forging and punching. The method includes hot forging a round steel bar to form a forged workpiece 33a including a mounting portion, an arm portion, and a column portion 7a that has a horizontal cross section having a circular shape; and forming a shaft hole 6, into which a hinge pin is to be inserted, by punching the column portion 7a so that the shaft hole 6 extends through an axial center of the column portion 7a by using a special die 52a and a punch 51. The die 52a has a gap formed therein so that, during punching, a slug is not generated and the column portion 7a expands outward when the punch 51 is pressed into the column portion 7a from a punching start point to a predetermined dimension, and a slug is generated and discharged when the punch 51 is pressed into the column portion 7a from the predetermined dimension to a punching end point. Thus, the shaft hole 6 can be formed so as to have a height that is twice the diameter thereof or larger. Therefore, with the manufacturing method, an automobile door hinge having high strength can be manufactured at low cost.

The method comprises a first process step consisting of shearing a cylindrical drawn segment on which there is carried out a cold impact extrusion by means of a punch. In that step the material flows laterally up to form a constant pattern hollow body (9) having at least one open end, on the other end (8) there being formed a solid pin (11) and a second open cavity of a smaller size. On each hollow body there are then carried out successive upsetting at the open end, adapted to impart the same with an undulated conformation. That end is then upturned and blocked.

The present invention has for its subject a hinge and a method of forming a closed cavity hollow male hinge. The method comprises a first processing step consisting of shearing a section from a cylindrival drawn blank followed by cold impact reverse-extrusion by means of a punch and die action; that step causes the material to be upturned laterally to form a constant pattern hollow body having an open end. Thereafter, there is carried out on said hollow body, as by striking with a die, a reduction of one portion thereof at the open end, thus defining a hollow pin. The open end of the latter is then upset and stopped to make the hollow body watertight.

The method of manufacturing sealed hollow male elements for hinge devices comprises the steps of shearing a segment off a drawn rod, and successively causing the material to flow laterally upwards such as by cold impact extrusion by means of a punch, to form a hollow body (5) of constant cross section having an open end. Thereafter, there is performed on said hollow body (5), as by impact with a die, a reduction of one portion at the open end (14), thus defining a hollow pin (8) having an open end (14). The latter is then stopped by press fitting a shaped body (13) thereinto.

The present invention has for its subject a hinge and a method of forming a closed cavity hollow male hinge. The method comprises a first processing step consisting of shearing a section from a cylindrival drawn blank followed by cold impact reverse-extrusion by means of a punch and die action; that step causes the material to be upturned laterally to form a constant pattern hollow body having an open end. Thereafter, there is carried out on said hollow body, as by striking with a die, a reduction of one portion thereof at the open end, thus defining a hollow pin. The open end of the latter is then upset and stopped to make the hollow body watertight.

57 The hinge device (1) comprises a male element (2) and a female element (3). The male element (2) includes a cylindrical body (4), wherefrom protrudes a pin (5), having a smaller diameter than the cylindrical body (4) and lying coaxial therewith. A seat is provided at the end of the pin (5), and a sphere (10) is maintained in the seat. The female element (3) is shaped to accommodate at least part of the pin (5). Both the male element (2) and the female element (3) are associable with casings.

A method for the manufacture of vehicle hinges produces, by blanking and cold-forming, hinges (11, 15) of the type comprising two flat rectangular plates (7, 9) each provided on one side with a flat projection (12, 16) of the same thickness as that of the plate (7, 9) terminating with a substantially cylindrical enlargement (13, 19) traversed by an axial hole (14,18) for receiving the hinge pin of the hinge (11, 15). In particular, the method according to the invention is usable for the manufacture of hinges (11, 15) of the type in which the axis of the said hole (14, 18) is offset with respect to the plane of the associated plate (7, 9). The invention also relates to a press tool usable in a press to effect the cold-forming operation which constitutes a stage in the manufacturing method of the hinge.