GB2155838A

GB2155838A - Punch press

Info

Publication number: GB2155838A
Application number: GB08502484A
Authority: GB
Inventors: Robert Frederick Gardner
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-03-16
Filing date: 1985-01-31
Publication date: 1985-10-02
Also published as: GB8406871D0; JPS60213320A; GB8502484D0

Abstract

A punch press has a plurality of punches 16 arranged in a matrix and a corresponding plurality of dies 18 correspondingly arranged in a matrix. The two matrices may be stationary with at least one ram 19 movable to align with any selected punch. A preferred arrangement comprises a 2-by-4 matrix with two rams (one large and one small for heavy and light duty uses respectively) movable along respective ones of the two columns of this matrix. Alternatively each punch and die in the matrix has its own actuating ram. <IMAGE>

Description

SPECIFICATION Punch press This invention relates to a punch press having a plurality of punches co-operating with a respective one of a plurality of dies, the punches being selectively operable.

Known punch presses include the turret punch press which has a plurality of punches mounted around a first rotatable disc and a corresponding die mounted around a second rotatable disc. In order to select a given punch, the two discs must be rotated to bring the selected punch and its corresponding die into alignment with a ram of the press which serves to actuate the punch. There are however problems in accurately registering the punches in their required position before actuation and also operating delays whilst the discs are rotated into position each time a fresh punch is selected.

Another known punch press includes three punches which are fixed in their positions and disposed in a line: respective fixed dies are aligned with these punches and furthermore each punch is provided with its own actuating ram. The above described problems of the turret punch press are avoided, but the arrangement must be limited to a small number of punches otherwise the press would be expensive in view of the number of rams required (one per punch) and also would require excessive travel for the workpiece parallel to the line in which the plurality of punches are disposed.

In accordance with this invention, there is provided a punch press comprising a plurality of punches arranged in a matrix and a corresponding plurality of dies correspondingly arranged in a matrix, there being a least one actuating ram with the or each ram being movable relative to the matrices of punches and dies so that any selected punch can be actuated, or there being one ram for each punch.

The arrangement of the punches in a matrix provides for a compact structure yet enabling a large number of punches (e.g. 9 punches arranged in a 3-by-3 matrix). The punch matrix and the die matrix may be stationarily mounted in the punch press; then a single ram may be provided together with means for moving it along two perpendicular axes to align with any one of the punches; alternatively, several rams may be disposed in a line parallel to one side of the matrix (the number of rams being equal to the number of punches in that side of the matrix) so that movement of the set of rams is only required in the perpendicular direction to enable the selected punch to be actuated. Instead of the punches and dies being stationary and the rams being moved, the rams may be stationary and the matrixes of punches and dies moved.

Each of the punch matrix and the die matrix may comprise a structure which is removably mounted to the punch press, for example by a plug-in arrangement of dowels, enabling one set of punches and corresponding dies to be removed and replaced by a different set of punches and dies.

Embodiments of this invention will now be described, by way of examples only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side view of a punch press in accordance with this invention; Figure 2 is a schematic plan view to show in principle the arrangement of punches and actuating rams in the press of Figure 1; and Figure 3 is a diagrammatic side view of the punch press with an alternative arrangement of matrix and rams.

In the example shown in Figures 1 and 2, a punch press comprises a rigid support structure formed of upper and lower horizontal limbs 10, 12 mounted together by a vertical limb 14. A matrix of punches 16 is removably mounted to the underside of the upper limb 10 adjacent its free end and a matrix of corresponding dies 18 is removably mounted to the upperside of the lower limb 12 adjacent its free end. Each matrix is a 3-by-3 matrix and a set of 3 rams 19 are mounted together and arranged in line transverse to the press (along the X axis) with means provided (e.g. a lead screw 15 driven by an electric motor 17 and engaged with the set of rams) to move the set of rams to any of the 3 required positions along the Y axis.A carriage 20 is provided for holding a workpiece 22 (typically a sheet of metal) and for moving the workpiece relative to the press in order to place the required portions of the workpiece in alignment with the required punch each time. Carriage 20 is provided with say two workpiece clamps 24 spaced apart along the X axis and means are provided for moving the carriage 20 along the X axis relative to a beam 26 which is mounted transverse to the press: such means may comprise a lead screw 21 mounted to beam 26, driven by an electric motor and engaged with the carriage 20. Similar means 23 are also provided for moving the beam 26 along the Y axis. A computer numerical control is provided for these means to ensure that the beam 26 is moved to the correct position along the Y axis and the carriage 20 is moved to the correct position along the X axis before each punch operation takes place.This numerical control selects which punch is required for each operation and automatically takes account of the offset of the different punches along the X and Y axes. The numerical control is further arranged to move the set of rams to the required row of punches and actuate the correct one of the rams for the selected punch.

Preferably a sensor 18a is arranged adjacent each die to detect if the workpiece lifts up following actuation of the corresponding punch. Such a lift-up occurs if the punch has become wedged within the aperture which it has punched, so that it does not withdraw from that aperture when the punch is resiliently returned to its inactive position after actuation of the ram. Alternatively, a sensor may be provided to monitor the linear displacement of the punch relative to the cylindrical stripper within which it slides: if the punch wedges with the workpiece, the punch will fail to retract fully into the cylindrical stripper under the action of its return springs after actuation of the ram, and the sensor may be arranged to monitor this. In either of these cases, the sensor provides a warning or disabling signal to stop the press until the workpiece is freed.

Although a 3-by-3 matrix of punches and dies has been shown, the matrix can comprise any other numbers. Particularly in the case of a 2-by-2 matrix, each punch may be provided with its own ram.

Figure 3 shows a prefered arrangement in which each matrix is made up of two columns of e.g. 4 punches 30 or dies 32 arranged transversely of the punch press and in which two rams 34, 36 are provided one behind the other. The two rams 34, 36 are large and small respectively for relatively heavy or light duty uses respectively, and they cooperate with respective ones of the two columns of punches and dies. The larger ram is required for the heavy duty uses but is limited in its rate of operation, and the smaller ram is able to operate at higher rates for the lighter duty uses. The two rams are mounted as close together as possible, with the body 36a of the smaller ram close against the actuating stem 34b of the larger ram and the body 34a of the larger ram overhanging the body of the smaller ram: the two columns of punches and dies are correspongingly close together for compactness.

The two rams may be mounted to a carriage 38 which is displaceable transversely of the punch press so as to align the selected ram with the selected punch-and-die pair. Alternatively, the two rams may be mounted for displacement independently of each other along their respective columns of punches. Whilst two columns of e.g. 4 punches and dies is shown in Figure 3,there may be more than two columns of punches and dies, with the carriage 38 displaceable to-and-fro within the press (along the Y-axis), in addition to the carriage being displaceable transversely of the press (or the two rams being independently displaceable transversely of the press). Displacement of the carriage 38 or rams 34, 36 may be effected by lead screw arrangements as described above.

An advantage of having stationary punches and dies with displaceable rams, rather than having displaceable punches and dies, is that the positioning of the rams is not required to be absolutely precise.

Claims

1. A punch press comprising a plurality of punches arranged in a matrix and corresponding plurality of dies correspondingly arranged in a matrix, and at least one actuating ram with the or each ram and the matrices of punches and dies being relatively movable so that any selected punch can be actuated, or there being one ram for each punch.

2. A punch press as claimed in claim 1, in which a single ram is provided together with means for moving it along two perpendicular axes to align with any one of the punches.

3. A punch press as claimed in claim 1, in which a plurality of rams are disposed in a line parallel to one side of the punch matrix, the number of rams being equal to the number of punches in that side of the matrix, and means are provided for moving the set of rams perpendicular to said line to align the rams with respective punches in any selected row of punches parallel to said side.

4. A punch press as claimed in claim 3, in which each matrix is a 3-by-3 matrix and there are three said rams.

5. A punch press as claimed in claim 1, in which two rams are provided, one being a relatively large ram and the other being a relatively small ram, the two rams being for relatively heavy and light duty uses respectively.

6. A punch press as claimed in claim 5, in which the two rams are disposed in a line parallel to one side of the punch matrix and means are provided for moving the two rams together perpendicular to said line to align the rams with respective punches in any selected row of punches parallel to said side.

7. A punch press as claimed in claim 5, in which means are provided for moving the two rams independently of each other along respective columns of punches in the punch matrix.

8. A punch press as claimed in claim 6 or 7, further comprising means for displacing both rams together parallel to said one side of the punch matrix, to align the rams with different columns of punches in the punch matrix.

9. A punch press as claimed in claim 6 or 7, in which there are two columns of punches, the two rams being displaceable along the respective columns.

10. A punch press as claimed in claim 9, in which each matrix is a 2-by-4 matrix, the two columns of punches or dies being arranged transversely of the press.

11. A punch press as claimed in any one of claims 5 to 10, in which the two rams are so mounted that the smaller ram has its body close against the actuating stem of the larger ram and the body of the larger ram overhangs the body of the smaller ram.

12. A punch press substantially as herein described with reference to Figures 1 and 2 or Figure 3 of the accompanying drawings.