Structural modifications for specific intended uses during manufacture of the workpieces are commonly required. For example, angle irons or structural angles (i.e., angle irons) often require that multiple holes be provided at various locations along the angles. Given the strength of the materials of the angles, significant forces are commonly required to create those holes, and thus significant mechanisms are required to generate those forces. Such forces are similarly required for other operations which might be required in which holes completely through the angle may not be required, for example, stamping identifying characters in the surface of the angle.
Machines have, of course, been used which can create holes (e.g., by punching or drilling), or stamp identifying information, in such workpieces, usually in a facility where the workpieces are being worked on (e.g., where a long blank is being punched to provide whatever holes are required for the intended use of the part pieces, with individual elements being sheared from the blank to form the individual part pieces).
Workpieces such as structural angles which are not simply flat and/or are made of strong material can be particularly difficult to work with in creating holes. For example, structural angles may have two longitudinal members or legs connected at right angles along an edge (often by bending a single flat longitudinal member along a line extending in the longitudinal direction), and typically are made of strong metals such as steel or iron to provide the strength required in many construction and manufacturing applications. In order to create holes in both of the legs of structural angles, separate punches have been used for each the two different legs of the angle, with one punch for one leg of the angle and a separate punch for the other leg of the angle. Those punches have shared a mechanism which serves to properly position the angle lengthwise for punching (e.g., along the X-axis), and have their own separate drives to move each individual punch head assembly to the correct location (along the Y- and Z-axes) for punching a hole at the selected longitudinal location of the structural angle. Not only can the cost of such dual punches be significant, but the speed of operation is also impacted since clearance requires that the punch head assemblies be spaced along the X-axis, resulting in time being required to move the entire structural angle along the X-axis for punching holes in both legs of the angle, even if the holes are at the same position along that X-axis. Further, precise positioning of holes which are supposed to be at the same longitudinal position on the angle may not be achieved if the structural angle is not moved accurately along its X-axis between the different punches.
Additionally, the operation of punch mechanisms for structural angles used heretofore have either resulted in inefficient handling of the structural angles or required additional mechanisms for the punch. That is, some machines have positioned the die portion of the punch so that it is always positioned so that it will be contacting one side of the angle (as desired during punching operation). However, such positioning necessarily results in the angle dragging on the punch die when it is moved through the mechanism. While such undesirable dragging has been avoided by either using support rollers which swing up to support the material clear of the die when moving the angle, or by providing a separate mechanism (e.g., separate hydraulic cylinders) to lift the punch die against the angle when punching is required, such lift methods have required separate items (hydraulic cylinders, rollers, tapered slide blocks, hydraulic valves, and the associated IO and timing) to make things work correctly.
The present invention is directed toward overcoming one or more of the problems set forth above.