Modular punch apparatus for punching complex shapes from a metal ribbon or tape

Punch press apparatus for sequentially punching shapes, particularly complex shapes, from a workpiece comprising a metal strip or ribbon (13), having

• a die plate (1);
• a punch element (P);
• a stripper plate (2) located above the die plate;
• a punch holer plate means (3, 3') carrying the punch element (P), located above the stripper plate;
• a plurality of posts (6) retaining and stacking said plates and guiding relative movement of the die plate (1), the stripper plate (2) and the punch holder plate means (3, 3') when carrying out a punching stroke;
• workpiece guide elements (9) located on the die plate (1) for guiding the workpiece in a predetermined path over the die plate between the die plate and the stripper plate;
• and
• wherein
• said stripper plate (2), when in a rest position between punching strokes and when out of engagement with the workpiece (13), is sapced from the top surface of the die plate by a distance which is only up to twice the thickness of the workpiece;
• at least the die plate (1) and the punch holder plate means are, in plan view, frame shaped and defined an open window or chamber (5) centrally of said plates for reception of modular inserts corresponding to the shapes to be punched;
• the stripper plate (2) is connected to at least two of said posts (6);
• resiliently yielding holding spring means (16, 916) are provided, positioned for coupling the die plate (1) to said at least two posts in predetermined position relative to the stripper plate (2) and spaced from the stripper plate sufficient to provide just enough clearance for the workpiece to move across the die plate between punching strokes;
• and force means (F, 4, 3, 29, 26) are provided acting on said punch holder plate means (3, 3') and on at least said two posts (6) and of sufficient strength for overriding said yielding holding means (16, 916) for moving said stripper plate into engagement with the workpiece to clamp the workpiece (13) during a punching stroke and further for moving the punch holder plate means and thus the punch element (P) against the workpiece (13);
• wherein the guide elements (9) are located at least in part below the workpiece (13), and
• said guide element define the lateral dimensions of said guide path only while leaving free the surface of the strip or ribbon first engaged by the punch element during a punching operation;
• guide spring means (10) are provided, coupled to the guide means (9) and positioned for biassing the guide means upwardly against the workpiece, and
• wherein the sum of the spring forces of the guide spring means (10) acting on said guide elements corresponds at least approximately to the weight of the stripper plate;
• and
• the guide spring means (10) compression path corresponds at least approximately to the distance (d) between the top surface of the die plate and a facing surface of the stripper plate (2) when the stripper plate is out of engagement with the workpiece (13) and between punching strokes, and the stripper plate, upon withdrawal of the punch element (P), is raised above the die plate (1) by a distance which is only up to twice the thickness of the workpiece.