Method and an apparatus for shearing heated metal bars to billets

In an apparatus including length-responsive shearing means (7, 8, 9) for shearing billets of given length (L) from heated bars, and conveyor means (2, 102) for normally returning the bars to an oven (100) following the billet shearing operation;

• the improvement wherein said conveyor means are operable to simultaneously longitudinally displace first (5) and subsequent (6) colinearly arranged contiguous bars outwardly of said oven to cause the leading edge of said first bar to pass through the shearing plane (13) of said shearing means toward a shearing position in which the forward edge of the first bar engages a stop (9) spaced a distance beyond said shearing plane equal to the given distance (L), whereupon said length-responsive shearing means operates to sever a billet from said first bar, said conveyor means normally being operable after the shearing operation to return at least said subsequent bar to the oven;
• and further including
• (a) detector means (22, 122, 222) for detecting whether or not the butt joint (s) defined between the trailing and leading edges of said first and subsequent bars entered a permissible zone during a first detection period when said first bar was displaced toward said shearing position, said permissible zone being arranged between said shearing means and said oven and being generally spaced said given distance (L) from said shearing means, said detector means being operable to inhibit the return of said subsequent bar to said oven in the event that a butt joint was detected within said permissible zone during said first detection period;
• (b) said conveying means being operable to displace the remnant portion of said first bar defined by the first billet shearing operation and said subsequent bar (6) to a shearing position in which the forward edge of said remnant portion is spaced said given distance (L) from said shearing plane, whereupon following a second length-responsive severing operation, the remnant and the forward portion of the subsequent bar are combined to form a second billet;
• (c) said detector means being operable to permit return of said subsequent bar to said oven following said second shearing operation in the absence of the detection of a butt joint within said permissible zone during the second displacement period.