Method of making a lever-type cam follower, and lever-type cam follower

A method of making a lever-type cam follower (1) out of thin-walled sheet metal, particularly for a valve train of an internal combustion engine, said cam follower (1) comprising two parallel side walls (2,3) connected by a crossbeam (4), an underside (9) of the crossbeam (4) having a support (6) for at least one gas exchange valve on one end (5), said support (6) being limited by guide walls (7,8) extending parallel to the side walls (2,3) characterized by the following steps to which further intermediate steps can be added:

• a) punching out a blank (12) from cold or hot rolled strip;
• b) making the support (6) and the guide walls (7,8) by a stamping and extrusion molding process by:
• b1) simultaneously applying, laterally of the guide walls (7,8) to be formed, two stamping dies (17a,17b) to the underside (9) and a continuous, smooth-faced counterdie (15) to the upper side;
• b2) the two stamping dies (17a, 17b) exclusively acting in such a way on the underside (9) of the blank (12) and having such a shape that a region of the blank (12) situated under these stamping dies is thinned out and a holding die (16) on whose side walls the flow of material of the guide walls (7,8) are formed by a backward plastic flow of the thinned-out material and which holding die at the same time services to guarantee the thickness of the crossbeam, and
• c) forming the side walls (2,3) with the crossbeam (4) which in the region or the support (6)., the crossbeam (4) has approximately the same thickness as the side walls enclosed by bending long sides (10,11) of the blank (12) at a right angle to the original blank (12), that the side walls (2,3) enclose together with the crossbeam (4), a smooth-faced U-profile.