End-forming toggle-press

Punch press, wherein:

• the press includes a die, for holding a workpiece;
• the press includes a punch-head, and a punch mounted therein;
• the press is arranged such that, in operation, the punch moves towards and away from the workpiece in the die, as the punch-head moves along a line termed the punch-line;
• the press includes a punch-head-guide, for guiding the punch-head along the punch-line;
• the press includes a ram-head, and includes a ram-head-guide, for guiding the ram-head along a ram-line;
• the arrangement of the press is such that the punch-line and the ram-line intersect, at a point-of-intersection, to form a T;
• the configuration of the T is such that the ram-line comprises the cross-bar of the T, and the punch-line comprises the stem of the T;
• the press includes a toggle-lever, having a punch-end and a ram-end;
• a punch-end-connection connects the punch-end of the toggle-lever to the punch-head;
• a ram-end-connection connects the ram-end of the toggle-lever to the ram-head;
• the arrangement of the press is such that, during operation, the punch-head undergoes a punch-cycle of movement, being movement of the punch-head along the punch-line from a punch-withdrawn start-position, to a punch-extended position, and back to a punch-withdrawn finish-position;
• the arrangement of the press is such that, during operation, the ram-head undergoes a ram-cycle of movement, being movement of the ram-head along the ram-line from a start-point, through the point-of-intersection, to a finish-point;
• the arrangement of the press is such that, during operation, the punch-cycle corresponds to the ram-cycle;
• the point-of-intersection lies on the ram-line, intermediate between the start-point and the finish-point;
• the punch-extended position of the punch-head occurs when the ram-end-connection is at the point-of-intersection;
• the arrangement of the press is such that when the punch-head lies at its fully extended position, the ram-head lies at the point-of-intersection, and the toggle-lever is aligned dead-centre with the punch-line, in that a line joining the punch-end-connection to the ram-end-connection lies along the punch-line;
• whereby the finish-point of the ram-head lies on the opposite side of the point-of-intersection from the start-point of the ram-head;
• the press includes an operable ram-actuator;
• the ram-actuator is effective, when operated, to drive the ram-head forcefully along the ram-line, from its start-point, through the point-of-intersection, to its finish-point, all in a first ram-sense along the ram-line;
• the ram-actuator includes a prime-mover, having a fixed-element fixed to the frame of the press, and having a movable-element, the prime-mover being an apparatus that converts prime energy from an energy source into powered mechanical motion of the movable-element along a prime-line;
• the ram-actuator includes a force-transmission-assembly, for converting forceful movement of the movable-element of the prime-mover along the prime-line into forceful movement of the ram-head along the ram-line;
• the force-transmission-assembly is so arranged as to introduce and define a mechanical-ratio between the movement of the movable-element of the prime-mover along the prime-line and the movement of the ram-head along the ram-line;
• and the structural arrangement of the ram-actuator is such that the mechanical-ratio when the ram-head is at the point on the ram-line where the mechanical-ratio is largest, is no more than double the mechanical-ratio when the ram-head is at the point on the ram-line where the mechanical ratio is smallest.