GB2169233A - Piercing press and tool holders for use therein - Google Patents

Abstract

Rotatable tools 60 are mounted in the turret plate 58 of a turret piercing press for rotation about their longitudinal axes in sleeves 79 within cassettes 64. External teeth 62 on the sleeves engage with a gearwheel 63 in the radially outer region of the cassette. A drive device 65, pivotably mounted 61 on the machine frame of the turret piercing press for movement about a horizontal axis, is connected to a rack 70 which is guided horizontally in a rack guide 73 and which is tangential to the turret plate 68. The rack 70 is arranged to be coupled, by a pivotal movement of the drive device 65, to a gearwheel 63. By actuation of the drive device 65, the rack 70 can thus be displaced horizontally to rotate a selected tool about its longitudinal axis within the sleeve 79 to any desired angular position. A single punch and die tool may be mounted for rotation about its longitudinal axis (7, Figure 2) by motors (29, 42, Figure 2). <IMAGE>

Description

SPECIFICATION Piercing press and tool holders for use therein This invention relates to piercing presses and particularly to holding devices for the tools of a piercing press.

Holding devices for piercing presses in which the tool is held to be rotatable by a motor drive about its particular longitudinal axis are known in many forms. With this type of tool holder one should be aiming for multi-purpose utilisation, especially with complex shapes to be punched.

From DE-PS 27 10 855 a punching machine is known having a single-head station in which the tool is secured on a rotary disc which for its part can be arrested in two rotary angular positions set 180 apart. With this construction of a piercing press, no settings of the tool are provided between the stop positions, so that its range of use is correspondingly limited.

DE-OS 30 20 532 shows a further piercing press having a single-head station wherein the tool is locatable in any rotary angular position about its own longitudinal axis. Because the tool of this known piercing press cannot perform any setting movement relative to a workpiece to be machined in order to achieve a determined working point, one therefore has the disadvantage, particularly with very heavy workpieces, that a considerable constructional and energy-consuming expenditure must be incurred for its positioning.

From DE-OS 3110 221 a turret piercing press is known wherein the tools, arranged in the peripheral region of the turret plate, are mounted to be rotatable about their longitudinal axes. Here, the driving of a tool is effected by an idling belt disc mounted on the turret plate, a clutch and brake unit mounted partially on the turret plate, and a drive motor which is fixed to the machine frame.

The idling belt disc secured to the turret plate serves, by means of sensors, to determine an exact rotary angular position of the tool. The majority of the driving and control elements for the rotation of a tool are consequently located in the narrow space between the machine frame of the piercing press and the turret plate. If several tools mounted on the turret plate are to be made rotatable in this way, then a comparatively complex mechanical construction of the drive mechanism becomes necessary. In addition to this, the use of a belt drive makes it more difficult to exchange the tools held in the turret plate.

In the turret punching press described in DE-OS 32 38 622 two tools are arranged diametrically opposite one another on a turret plate and are rotatable simultaneously about their longitudinal axes by means of a mechanical coupling. The coupling between these two tools is formed by a connecting rod extending at right-angles to the turret plate with the connecting rod cooperating with a locating device for the arresting of the tools. The force transmission to the tools is effected by means of worm shafts which are connected to the connecting rod by joints, wherein the end regions of the worm shafts can be coupled to a stationary drive system.Again in this piercing press, several elements of the drive are located on the turret plate, and there is also the further disadvantage that for constructional reasons one cannot have any number of the tools mounted on the turret plate arranged to be rotatable.

These known embodiments of tool holder device for piercing presses, where the tools are rotatable, thus have the disadvantage that they present a very complex mechanical structure, that only a proportion of the tools mounted on the turret plates can be mounted rotatably, or that, in the case of a piercing press with a single-head station, the handling of large workpieces is bound up with a correspondingly high machining cost in order to achieve the positioning.

It is an object of the present invention to provide a piercing press in which the tool holding device, while avoiding the disadvantages apparent from the known presses, has a simple structure, has a flexible application to the piercing press, and in particular is suitable for use within the framework of a CNC control system.

In accordance with one aspect of the invention there is provided a piercing press formed as a turret piercing press having at least one turret plate, the press comprising holder means for tools each comprising at least a punch and a matrix die, wherein at least some of the tools are displaceable perpendicular to the surface of a workpiece to be machined and are mounted for rotation about their respective longitudinal axes each through any angular step under the action of driving means, wherein all the operating elements of said driving means are positioned in the peripheral region of the turret plate or plates, and wherein the rotatable tools are mounted on the turret plate or plates by means of cassettes which individually, as desired, are coupled to or can be coupled to said driving means.

It is essential that all the operational elements of the driving means which make possible the rotary movement of the tools are arranged in the peripheral region of the turret plate or plates and that the machine construction of the piercing press is not in any way hindered. From this it follows that there is good accessibility. By arranging that the tools are mounted in cassettes which can be coupled individually to the driving means, one achieves the possibility of fitting the turret plate with any number of rotatably mounted tools. The cassette-type arrangement of the tools also brings about the advantage of simplified tool exchange. The basic structure of the cassettes guiding rotatable tools is optional, subject only to the fact that a connecting means must be provided between the tool and an external driving element.

Preferably, the cassettes are provided with gearwheels or like transmission means which on the one hand are connected to the tools and on the other hand are coupled to or can be coupled to said driving means. One preferably arranges that the gearwheels can be arrested in a defined position. It is important that these gearwheels should form a fixed component of the cassettes, and consequently can be received together with the cassette in the turret plate or can be inserted therein.

In this way one achieves a high measure of flexibility in the equipping of the turret plate with rotatable tools.

The driving means preferably comprises, for the or each turret plate, a motor which is secured to a pivotable holder, by the pivotal movement of which a coupling of the driving means to the cassette or to a take-off means can be introduced. For the motorised execution of this pivotal movement one can for example use a piston-cylinder unit, a setting motor or the like. Rotation of the tool can be brought about by displacement of a rack sliding in a rack guide, with the rack being in connection both with the gearwheel associated with the cassette and also with a toothed belt drive for the motor secured to the holder. The gearwheels associated with the cassettes are preferably arranged at the radially outermost part of the cassettes, so that the rack can be positioned outside the region of the turret plate.

An arresting of the gearwheel associated with the cassette is preferably brought about by means of the driving means, for example by means of a control surface on the holder itself. Since an arresting of the gearwheel is in practical terms only possible in one angular position, this creates a constant defined initial value at the beginning of a rotary process, which makes it suitable for a CNC control system by means of which not only is tool exchange controlled, but also the rotary angular position of the tool located in the particular work station of the turret piercing press. With the driving means uncoupled, a further rotation of the tool is consequently not possible.The realisation of the arresting of the gearwheel can be achieved by providing the gearwheel with an annular groove which has a for example U-shaped radially extending recess, with the pin of a guide block being insertable into the annular groove to prevent further rotation, thus representing an arresting mechanism which is structurally very simple to put into practice.

Alternatively, the driving means may comprise a ring gear which is guided slidingly in relation to the turret plate and which encircles the turret plate, the ring gear on the one hand being in engagement with the gearwheels or like transmission means and on the other hand being in engagement with a gearwheel of a motor. The ring gear preferably is toothed internally and externally. With this arrangement, several rotatable tools can thus be coupled permanently to the driving means.

The motors are preferably numerically controllable. This is a prerequisite for the utilisation of the holder device within the framework of a CNC control system.

In accordance with another aspect of the invention there is provided a piercing press formed as a piercing press with a single-head station, the press comprising holder means for a tool comprising at least a punch and a matrix die, wherein the tool is displaceable at least partially perpendicular to the surface of a workpiece to be machined and is mounted for rotation about its longitudinal axis through any angular step under the action of driving means, wherein the tool is additionally mounted to be displaceable in a direction parallel to the plane of the workpiece, and wherein the driving means can be coupled to the tool.It is important in connection with this that the tool should be mounted so as to be capable of an adjustment movement in order to bring the tool into a defined position in relation to the workpiece, with the driving means causing the rotation of the tool about is longitudinal axis being couplable to the tool or alternatively to a holding element receiving the tool rotatably. The driving means thus carries out the adjusting or setting movement of the tool.

Preferably, the driving means comprises a carriage which is associated with the lower part or the upper part of the tool, the carriage carries a motor for rotation of that tool part, and the motor is connected to the tool part by gear means either directly or through the intermediary of a sleeve.

In a preferred embodiment the press is one in which the carriage is displaceable in a plane parallel to the plane of the workpiece and parallel to the guide of a guide block carrying the associated tool part, and in which the gear means is preferably formed as a toothed belt drive.

It is desirable that the carriages should be displaceable accurately parallel to the guide of a guide block carrying a tool. This displaceability can be achieved for example by guide grooves, or alternatively by rollers. One only has to ensure that the carriages are unambiguously guided on all sides. The carriage is preferably equipped with arresting means so that it is arrestable relative to the machine frame of the piercing press, as well as also being couplable to the guide block carrying the tool.

Preferably, the arresting means comprises a piston-cylinder unit which is equipped with two piston rods for arresting the carriage on the one hand and for coupling it to the guide block on the other hand. The piston-cylinder unit may be formed such that when the carriage is uncoupled from the guide block the carriage is arrested in relation to the machine frame of the piercing press. This is constructionally simple to put into practice, particularly with a view to realising these advantages by the use of just one piston-cylinder unit. In the uncoupled state the carriage consequently always adopts defined positions reproducible for a CNC control system.

The press may also have the carriage provided with a further piston-cylinder unit which cooperates with a mechanism arranged to lock the tool in a locatable angular position. The mechanism may comprise a lever which is provided with a latch arresting the rotational movement of the tool and in which the lever is under the bias of spring means.

The latch can be brought into engagement with toothing on the tool or on a sleeve guiding the tool. This arresting is thus achieved with means which are located on the carriage, namely a pistoncylinder unit which cooperates in a mechanical manner with the lever carrying the latch.

A coupling element may be provided on the guide block for displacement in a plane parallel to the plane of the workpiece. The coupling element serves for the displacement of the tool and, in this way, with the carriage coupled up, also serves simultaneously for displacement of the driving means.

Several embodiments of the invention will now be described in the following by way of example and with reference to the drawings. In the drawings: Figure 1 is a sectional view of a first embodi ment of piercing press, taken along the line l-l of Figure 2; Figure 2 is a sectional view of the piercing press perpendicular to the section plane of Figure 1; Figure 3 is a cross-sectional view taken along the line Ill-Ill of Figure 2; Figure 4 is a cross-section taken along the line IV-IV of Figure 2; Figure 5 is a plan view of the lower turret plate of a second embodiment of piercing press, formed as a turret piercing press; Figure 6 is a vertical section through the end zone of the two turret plates of the turret piercing press Figure 7 is a view on an enlarged scale of the zone marked VII in Figure 6;; Figure 8 shows the zone marked VIII in Figure 6, on an enlarged scale with the holder in its uncoupled position; Figure 9 is a sectional view taken along the line IX-IX of Figure 8; Figure 10 is a sectional view taken along the line X-X of Figure 7; Figure 11 is a sectional view taken along the line Xl-Xl of Figure 5; Figure 12 is a view corresponding to Figure 11 of the driving mechanism of the upper turret plate; Figure 13 is a plan view of the lower turret plate of a turret piercing press with a different embodiment of the tool holders; and, Figure 14 is a sectional view taken along the line XIV-XIV of Figure 13.

Referring first to Figures 1 to 4, there is described in the following a first embodiment of tool holder in accordance with the invention. The tool holder is, in this embodiment, adapted for a piercing press with a single-head station, in which the tool is held so as to be displaceable in a linear direction relative to the workpiece to be machined.

In Figure 1 the reference numeral 1 designates a guide block for a matrix die which is mounted, in a manner to be described later, so as to be displaceable in the direction of the arrow 1' along guide rails 22. The guide rails 22 are secured, in a manner which will not be described in greater detail, to a machine frame 23 which forms the base of the piercing press.

Reference numeral 2 designates a guide block for a punch holder 9. This guide block 2, in a similar manner to the guide block, is mounted, in a manner to be described later, so as to be displaceable in the direction of the arrow 1' along guide rails 33. The guide rails 33 are secured, in a man ner which will not be described in more detail, to the upper part of the machine frame 23. A punch 10 projects out from the underside of the punch holder 9 and projects into an aperture 19 in an insert 13 of a stripper 12. The insert 13 is mounted so as to be rotatable relative to the stripper 12. The stripper 12 is held by a stripper shoe 11 in a man ner which is known per se and which is therefore not described here in more detail.

A connecting pin 16 projects upwards from the upper portion of the punch holder 9 and is arranged to be coupled to a driving rod, in a manner which is not shown, in order to actuate the punch 10.

Reference numerals 14 and 15 indicate pins by means of which, again in a manner which is not illustrated, the stripper shoe 11 and consequently the stripper 12 are actuated during the stamping process.

The matrix die 6 is set into a die holder 5 of a sleeve 3 so to be non-rotatable relative thereto, with the sleeve 3 itself being mounted rotatably in a bore 8 of the guide block 1. The sleeve 3 is drivable for rotation about its longitudinal axis 7 by means of teeth 4 which are machined into its outer peripheral surface. More detailed reference to this will be made hereinafter.

The punch holder 9 is for its part seated in a sleeve 17 so as to be non-rotatable relative thereto, with the sleeve itself being mounted so as to be rotatable about the longitudinal axis 7 in a bore 17' of the guide block 2. The driving of the sleeve 17 is effected in a similar manner to that of sleeve 3, by means of teeth 4' which again will be described in more detail hereinafter.

An adjusting spring is indicated at 18, which is secured to the punch holder 9 and slides parallel to the longitudinal axis 7 within a groove 18' machined into the sleeve 17.

It is essential that both the punch holder 9 and also the matrix die 6 can be rotated about the longitudinal axis 7 through rotation of the sleeves 3, 17 which carry them, by means of the teeth 4,4', so that the punch holder and the matrix die can thus take up any, accurately adjustable, angular positions. Since the insert 13 encircles the punch 10 in the region of the aperture 19 with only a small amount of play, a rotation of the punch holder 9 in general has the effect also of causing a rotation of the insert 13 relative to the stripper 12.

In Figure 2 it can be seen that the guide rails 22, 33 extend respectively on each side of the guide blocks 1,2, and thus are in engagement with respective guide grooves 21 and 32 which are machined into the guide blocks 1,2.

Actuating elements for the pins 14, 15 are indicated at 34, while reference numeral 35 indicates a plunger arranged to be coupled to the connecting pin 16 for the actuation of the punch 10 (Figure 1).

A guide rib 30 is provided on the inner guide rail 22, the guide rib extending perpendicular to the plane of the drawing of Figure 2 and lying opposite a further guide rib 30' which extends parallel to guide rib 30 and is spaced therefrom. The guide ribs 30, 30' are fixed rigidly with respect to the ma chine frame 23 and each serve to guide two sets of rollers 31 of a lower carriage 36, these sets of rollers being arranged spaced from one another viewed perpendicular to the plane of the drawing of Figure 2. The three rollers of each roller set rest respectively on the lower, the upper and the side surfaces of the guide ribs 30, 30' extending perpendicular to the plane of the drawing of Figure 2, and thus make it possible to displace the carriage 36 in this direction.

Reference numeral 50 indicates an arresting sleeve which is secured to the machine frame 23 and which can be brought into engagement with the piston rod of a piston-cylinder unit 48, the piston rod bring formed as a check pin 51. The cylinder of this piston-cylinder unit 48 is secured to the carriage 36 so that by an extension of the check pin 51 the carriage 36 can be prevented from movement perpendicular to the plane of the drawing of Figure 2.

The carriage 36 additionally carries a motor 29, on the output shaft of which there is fitted a toothed belt pulley 28 which is connected by means of a toothed belt 27 with a further toothed belt pulley 26 which is mounted on a shaft 45. This shaft 45 is in engagement, by way of a gearwheel 25 mounted on the shaft and an intermediate gearwheel 24, directly with the toothing 4 of the sleeve 3. Whereas the shaft 45 carrying the gearwheel 25 is mounted on the carriage 36, a shaft 37 carrying the intermediate gearwheel 24 is mounted on the guide block 1 in a manner which will not be described in more detail.

By actuation of the motor 29, the sleeve 3 and consequently the matrix die 6 can be rotated about the longitudinal axis 7. The motor 29 can be provided for this purpose for example as a dc motor, or alternatively as an ac motor or hydraulic motor.

In connection with this it is only necessary that the particular motor 29 which is used should be numerically controllable, so that by its actuation through particular angles of rotation one can achieve accurately predetermined rotations of the matrix die 6.

On the rearward side of inner guide rail 33 there is provided a guide rib 40 which extends perpendicular to the plane of the drawing of Figure 2 and which lies opposite, and spaced from, a guide rib 40' extending parallel to it. Both guide ribs 40,40' are rigidly fixed in relation to the machine frame and serve to guide an upper carriage 38. The guidance of the upper carriage 38 is effected in a similar manner to that of the lower carriage 36, by means of respective pairs of sets of rollers 41, each consisting of three rollers, each being associated with a respective guide rib 40,40', and which, like the roller sets 31, make rolling contact with the guide ribs with which they are associated.

Reference numeral 42 indicates a motor which, in a manner identical to that of the motor 29, is connected by way of a toothed belt pulley 28', a toothed belt 27', a further toothed belt pulley 26', a gearwheel 25' and an intermediate gearwheel 24', with the toothing 4' of the sleeve 17. The toothed belt pulley 26' and the gearwheel 25' are mounted on a shaft 45' which for its part is mounted on the upper carriage 38, whereas the intermediate gearwheel 24' is mounted on a shaft 37' which is mounted in the guide block 2. By actuation of the motor 42 the angular setting of the punch holder 9 is thus adjustable. The same demands are set in terms of the type and construction of the motor 42 as are set for the motor 29.

Reference numeral 50' indicates an arresting sleeve which can be brought into engagement with a check pin 51' which is actuated in a manner which will be described hereinafter.

The upper carriage 38 can be seen particularly clearly in Figure 3 where it is shown in plan view.

Check pin 51' is constituted by the piston rod of a piston-cylinder unit 48', the cylinder of which is secured to the carriage 38. This piston-cylinder unit 48' is additionally provided with a further piston rod at its end remote from the check pin 51', said further piston rod being formed as a check pin 51" which can be brought into engagement with an arresting sleeve 53 which is secured to the guide block 2. The piston-cylinder unit 48' is arranged in such a way that when check pin 51" is extended then check pin 51' is retracted, so that in this one setting phase the upper carriage 38 is coupled to the guide block 2, whereas in the other setting phase, namely with retraction of check pin 51", check pin 51' is extended and the upper carriage 38 is established in a rest position.

Reference numeral 52 indicates a coupling element which is connected to a drive member (not shown) for the horizontal displacement of the guide block in the direction of the arrow 54.

Reference numeral 39 indicates a lever which is pivotably mounted on a shaft 43 secured to guide block 2, and which, under the action of a spring element 44, is established in a first set position. In this first set position the lever 39, which has a latch 46 formed on the lever, has the latch in engagement with the toothing 4' of the sleeve 17, so that the sleeve is held in ratchet manner in its rotated position. In order to unlatch the lever 39, a pistoncylinder unit 47 is provided on the upper carriage 38, the unit having its piston rod 49 carrying a switching member 55' provided with a ramp surface 55. The switching member 55' is constructed and arranged in such a way that its ramp surface 55 can come into engagement in alternating manner with a pin 56 which extends from the lever 39 perpendicular to the plane of the drawing of Figure 3. By actuating the piston-cylinder unit 47, and by means of the ramp surface 55 and pin 56, the lever 39 can thus be pivoted against the action of the spring element 44 into an unlatched or release position. The lever 39 serves in this way, in combination with a CNC-control system which is not illustrated here, to hold the tool, namely the punch 10 (Figure 1), always in a predeterminable datum position.

Figure 4 provides a view of the lower carriage 36, corresponding to the illustration of the upper carriage in Figure 3, the lower carriage being arrestable relative to guide block 1 by means of a check pin 51"' which is formed by a second piston rod of piston-cylinder unit 48. The piston-cylinder unit 48 is, for the rest, formed just like piston-cylin der unit 48', i.e. so that with extension of check pin 51"' check pin 51 is retracted, so that the guide block 1 with the lower carriage 36 coupled to it can then be displaced in the direction of the arrow 57 by means of a coupling element which is not shown in the drawing. Check pin 51"' is displaced for this into engagement with an arresting sleeve 53' of the guide block 1.

The lower carriage 36 carries a further piston-cyl inder unit 47' whose piston rod 49' includes a switching member 55"' provided with a ramp surface 55". The switching member 55"' cooperates with a pin 56' on a lever 39' which is mounted rotatably on a shaft 43' secured to the guide block 1 and is in engagement, in one set position, with the toothing 4 of the sleeve 3 under the action of a spring element 44' as well as a latch 46'. By extension of the switching member 55"' by means of the piston-cylinder unit 47', the lever 39' can thus be pivoted about the shaft 43' against the bias of the spring element 44' so that the latching of the sleeve 3 created by the latch 46' is released.

The first embodiment of tool holder in accordance with the invention described above with reference to Figures 1 to 4 is shown on a punching machine having a single-head station where the tool set, consisting essentially of punch holder and matrix die, can be traversed in the direction of the arrow 54 (Figure 3) in relation to a workpiece which is to be machined, and wherein the guide blocks 1,2 are displaced jointly by means of a drive system which is not illustrated. By actuating the piston-cylinder units 48, 48', the lower carriage 36 and the upper carriage 38 can be coupled to the guide block associated therewith, so that these carriages are displaceable jointly with the guide blocks. By coupling on the carriages 36, 38 the possibility is created of rotating the tool, namely the punch or punch holder and the matrix die, into an accurately presettable angular position.The motors 29, 42 associated with this rotation of the tool are connected for this purpose to a CNC-con trol system which is not illustrated and by means of which the motors 29, 42 can be moved in complete synchronism through the same angular degree. It is nevertheless also possible, in the alternative, to control the rotation of the two elements of the tool, i.e. punch and die, individually.

Upon uncoupling of the carriages 36, 38 from the guide blocks 1,2 by withdrawal of the check pins 51"', 51" the tool parts, namely the sleeves 3,17, are arrested in an established datum position by means of the levers 39, 39' whose respective latches 46,46' are brought into engagement with the toothing 4,4' for this purpose. In this way one ensures that upon a renewed coupling up of the carriages 36, 38 to the guide blocks 1,2 one always has a defined initial value for the angular setting of the tool parts, which the CNC-control system can use as its base for the further operation of the piercing press.

In the uncoupled state the carriages 36,38 are always held located in relation to the machine frame of the piercing press by means of check pins 51, 51' and, in this state, thus take up an accurately defined position. If desired, further arresting sleeves 50, 50' may be arranged along the dis placement path of the carriages 36,38 in the direction of the arrows 54,57, in order to be able to locate the carriages in different positions.

Control devices associated with the motors 29, 42 for monitoring the angular position of the tool parts have been omitted from the drawings in order not to destroy the clarity of the drawings. It is essential however that the several motors and drives are connected to a CNC-control system, so that the piercing press equipped in this way can perform an automated operation even with tools which have to be rotated about their respective longitudinal axes through defined angular values during the machining operation.

A further embodiment of tool holder in accordance with the invention will now be described, with reference to Figures 5 to 12, and in relation to a turret piercing press in which, in a manner known per se, two turret plates are arranged to be rotatable one above the other about a vertical axis.

Figure 5 is a plan view of the lower turret plate 58 which is mounted to be rotatable about an axis 59 which extends perpendicular to the plane of the drawing of Figure 5. The turret plate 58 carries rotatable tools 60 and non-rotatable tools 61 around its periphery, these tools being capable of being distributed in essentially any sequence around the circumference. The tools, here the matrix dies, are located, in a similar manner to the illustration according to Figures 1 to 5, in rotatably mounted sleeves 79 which are provided around their peripheries with toothing 62.The toothing of each of the rotatable tools 60 is in engagement with respective gearwheels 63 which, in a similar manner to the intermediate gearwheels 24 in the tool holder according to Figures 1 to 5, are mounted in respective cassettes 64 which each receive the sleeve 79 and which are comparable in terms of function with the guide blocks 1,2.

At one side, on the machine frame for the turret plate 58, a toothed rack 70 is mounted to be displaceable horizontally in the plane of the turret plate within a rack guide 73 in such a way that the rack can be brought into engagement with the respective gearwheels 63. The rack 70 is for its part drivable by way of a gearwheel 91 of a drive mechanism 65 which will be described hereinafter.

By displacement of the rack 70 by means of the drive mechanism 65, with the consequent rotation of the gearwheels 63 and the toothing 62 of the respective sleeves 79, a matrix die can be rotated about its axis extending perpendicular to the plane of the drawing of Figure 5. It is of considerable importance that in this arrangement the drive mechanism should be formed in such a way that the rotation of the matrix die can be effected through accurately presettable angular steps.

Figure 6 is a cross-sectional view through the two turret plates 58, 66 which are arranged one above the other. From this can be seen one of the sleeves 79 of the lower turret plate 58 and one of the corresponding sleeves 80 of the upper turret plate 66, both of which sleeves are provided peripherally with toothing 62. The respective tools, namely the matrix die 6 and the punch holder 9, are held in these sleeves 79, 80 so that they cannot rotate relative to the sleeves.

One can also see the position of a shaft 67 by means of which the gearwheel 63 which effects a coupling between the toothing 62 and the rack 70 is mounted in the cassette 64. In the cassette 64 of the upper turret plate 66 a gearwheel 63' is mounted in similar manner. This gearwheel 63' likewise forms a coupling member between the toothing 62 of the sleeve 80 and a rack 70' which is guided for sliding movement in a rack guide 73' perpendicular to the plane of the drawing of Figure 6.

The two rack guides 73,73' are mounted pivotably by means of respective holders 68, 68' for movement about pins 69' extending parallel to each other and perpendicular to the plane of the drawing of Figure 6. By outward pivoting of the holders 68, 68' about these pins 69' the engagement between the respective racks 70,70' and the gearwheels 63, 63' is consequently released.

In Figures 7 to 10 the rotary drive for the sleeve 79, which corresponds in all aspects to that for the sleeve 80, is shown in detail. Thus, Figures 7 and 10 show this rotary drive in a switched position coupled up to the sleeve 79, while Figures 8 and 9 show the rotary drive in a switched position where it is uncoupled from the sleeve 79.

The gearwheel 63 is provided on its underside with an annular groove 84 which extends concentrically about the axis of the shaft 67. The annular groove 84 is provided at one position with a semicircular recess 85 which extends radially outwardly with reference to the gearwheel 63 from the annular groove 84. Below the gearwheel 63 a guide block 87 is guided in a corresponding radial guide of the turret plate 58 which is not shown here, the guide block 87 being displaced into its radially innermost position, against the action of a spring element 88, by means of the rack guide 73 in the switching phase shown in Figure 7. The guide block 87 is consequently mounted to be displaceable in the plane of the turret plate 58. A pin 86 projects upwardly from the upper region of the guide block 87 and projects into the annular groove 84 of the gearwheel 63.The pin 86 is, for the rest, dimensioned so that upon radial displacement of the guide block 87 outwardly it will fit into the semi-circular recess 85 of the gearwheel 63.

Upon pivotal displacement of the holder 68 outwards about the pin 69' shown in Figure 6, the guide block 87 can consequently be displaced outwardly under the bias of the spring element 88 so that the pin 86 is brought into engagement with the recess 85. One ensures in this way that the sleeve 79, and consequently the tool guided in the sleeve and non-rotatable relative thereto, can be stopped in a determined angular position definable as a datum position, so that one always has a unique value for a CNC-control system.

The gearwheel 63' of the upper turret plate 66, and consequently the tool held in this turret plate, are locatable in a comparable manner in terms of their own rotary angular setting.

Figure 11 shows the drive unit 65 in detail. An angle-piece 69 is secured to the holder 68 and carries a motor 71. The motor 71 drives a gearwheel 74 by means of a toothed belt 72, and the gearwheel 74 is in engagement with the rack 70. The gearwheel 74 is mounted on a shaft 75 which is mounted by means of a holder on the angle-piece 69. The shaft 75 carries a toothed belt pulley 76 at its end remote from the gearwheel 74, and the toothed belt pulley 76 is driven by the toothed belt 72.

The motor 71 can be formed as a dc motor, an ac motor or a hydraulic motor, and is equipped with control devices which are not shown for monitoring the angular position of the sleeve 79 which is driven by the motor.

The angle-piece 69, and consequently the holder 68, are connected to a piston-cylinder unit 77 whose cylinder is coupled to a bracket 78 of the machine frame of the turret piercing press and whose piston rod is coupled to the holder 68. By energising the piston-cylinder unit 77, the holder 68 together with the elements connected to it can thus be pivoted about the shaft 69', so that engagement between the rack 70 and gearwheel 63 driving the sleeve 79 is released.

Figure 12 shows the drive unit 65' which is associated with the upper turret plate. This is constructed in a manner similar to that of the drive unit 65 of the lower turret plate and consists of a motor 71' which is mounted on a member secured to the holder 68', with the motor 71' driving a gearwheel 74' by way of a toothed belt 72' and a toothed belt pulley 76', the gearwheel 74' being in engagement with the rack 70'.

Reference numeral 78' indicates a bracket secured to the machine frame of the turret piercing press and to which the cylinder of a piston-cylinder units 77' is coupled, the piston rod of that unit being coupled to the holder 68'. By energisation of this piston-cylinder unit 77', the holder 68' can thus be pivoted about the shaft 69' and in this way one can release the engagement between the rack 70' and the sleeve 80. The same requirements are demanded for the motor 71' as are necessary for the motor 71.

It will be appreciated from the foregoing description that, with the turret piercing press according to Figures 5 to 12, by actuation of the motors 71,71' the respective tool sets consisting of punch and matrix die can be rotated about their longitudinal axes, and indeed through accurately defined angular values. The rack 70 remains connected with the particular tool which is located at any one time in the working station of the turret piercing press. If the tool located in the working station is to be changed, then just by appropriate actuation of the piston-cylinder units 77,77' the engagement between the racks 70,70' and the gearwheels 63,63' is released and thereafter the turret plates 58,66 can be rotated about their axes 59 sufficiently for the desired tool to become located in the working station.If one is talking here about a non-rotating tool, then, during the working process with this tool set, the rack 70 remains in the outwardly pivoted position shown in Figures 8 and 9.

If on the other hand one is talking about a rotatable tool, then by appropriate actuation of the piston-cylinder units 77,77', an engagement is produced between the racks 70,70', and the respective gearwheels 63,63' and by subsequent actuation of the motors 71,71' the desired angular setting of the tool is set up. If the working process is terminated with the rotatable tool, then this tool is rotated into its datum position, again by actuation of the motors 71,71', and is locked in this position, after pivotal movement of the rack 70, by means of the pin 86 on the guide block 87. Subsequently, a further tool change can be carried out by rotating the turret plate 58. A rotary process involving the rotatable tools in this way always sets them up in their datum position, since for a CNCcontrol of the rotary process one must always have a defined initial value.

Figures 13 and 14 show a further embodiment of tool holder in accordance with the invention which can find application in a turret piercing press.

Figure 13 is a plan view of the lower turret plate 58 which shows both rotatable tools 60 and also non-rotatable tools 61 around the periphery of the plate. In this embodiment the rotatable tools which, just as in the case of the preceding embodiments, are set non-rotatably in sleeves are associated each with a gearwheel 63 which is mounted in the same manner as in the embodiments already described above and which is in engagement with the toothing of the aforesaid sleeve. The gearwheels 63 are in engagement on their sides remote from the sleeves with a ring gear 81 which is provided with both internal and external teeth.

The ring gear 81 which is located in a common horizontal plane with the turret plate 58 has on its underside an annular guide member 83 which extends axially downwards from the ring gear and which is guided slidingly in the circumferential direction in a correspondingly shaped, here Tshaped, groove 82 in the turret plate 58. The guide member is thus held positively in the axial direction on both sides. The radially outer edge of the ring gear 81 projects beyond the edge of the turret plate 58.

Reference numeral 89 indicates a drive device associated with the ring gear 81 and which includes a gearwheel 90 which is permanently in engagement with the external teeth of the ring gear 81.

The drive device 89 comprises a motor 91 which is secured to a bracket 92 of the machine frame of the turret piercing press, with the gearwheel 90 being mounted on the take-off shaft 93 of the motor. The motor 91 may be formed as a dc motor, an ac motor or a hydraulic motor, and is in each case equipped with a locking brake which makes it possible to maintain the motor in accurately definable angular positions of its take-off shaft 93. It will be appreciated that by actuation of the motor 91 with the turret plate 58 stationary, the ring gear 81 and consequently the rotatable tools 60 can be rotated.

The upper turret plate shown in Figure 14 at 66 is, in an identical manner to the lower turret plate 58, equipped with a ring gear 81', and its drive mechanism 89' is formed correspondingly and is equipped with a motor 91'. A more detailed description of this drive mechanism 89' is therefore omitted.

The work station of the turret piercing press is indicated in Figure 13 by A.

If a new tool is to be introduced into the work station, then by rotation of the turret plates 58, 66 with the ring gears 81, 81' braked firmly by means of the motors 91, 91' the particular tool is moved into the work station A. During this rotation of the turret plates all tools 60, 61 rotate synchronously about their individual axes. After the particular tool 60 has reached the work station A, with the turret plates 58, 66 now stationary, the desired angular setting a of the tool is set up by actuating the motors 91,91'. The mounting of the tools in the turret plates 58, 66 is effected in such a way that these tools, upon reaching the work station A, adopt an accurately defined datum or middle position. If, consequently, the particular tool is located in the work station in a position which deviates from this middle position, then upon change-over of this tool before the rotation of the turret plate, this tool is rotated further into its middle or datum position, so that for a CNC control system with which the motors 91, 91' are connected, just like the drive of the turret plates, there is always a defined initial value of the rotary angular position of the tool.

Claims (28)

1. A piercing press formed as a turret piercing press having at least one turret plate, the press comprising holder means for tools each comprising at least a punch and a matrix die, wherein at least some of the tools are displaceable perpendicular to the surface of a workpiece to be machined and are mounted for rotation about their respective longitudinal axes each through any angular step under the action of driving means, wherein all the operating elements of said driving means are positioned in the peripheral region of the turret plate or plates, and wherein the rotatable tools are mounted on the turret plate or plates by means of cassettes which individually, as desired, are coupled to or can be coupled to said driving means.

2. A piercing press according to claim 1, in which said cassettes are provided with gearwheels or like transmission means which on the one hand are connected to the tools and on the other hand are coupled to or can be coupled to said driving means.

3. A piercing press according to claim 2, in which the gearwheels or like transmission means can be arrested in a defined position.

4. A piercing press according to any preceding claim, in which the driving means comprises for the or each turret plate a motor which is secured to a holder which is pivotable relative to the turret plate, said holder at the same time comprising a coupling means for rotation of the tool and connected to the motor by gear means.

5. A piercing press according to claim 4 when dependent on claim 2 or 3, in which the gear means comprises a toothed belt pulley and the coupling means comprises a rack which can be brought into engagement with the gearwheel or like transmission means.

6. A piercing press according to claim 5, in which the holder is pivotable about an axis extending substantially parallel to the plane of the turret plate.

7. A piercing press according to claim 5 or 6, in which the rack is guided slidingly in a rack guide which extends substantially parallel to the plane of the turret plate and tangentially to the turret plate.

8. A piercing press according to claim 2 or any of claims 3 to 7 when dependent on claim 2, in which said driving means is operationally connected to a guide block by means of which the gearwheel or like transmission means can be arrested.

9. A piercing press according to claim 8, in which the guide block is guided displaceably on the turret plate or on the cassette and is provided with pin means which can be brought into engagement in a positive manner with the gearwheel or like transmission means.

10. A piercing press according to claim 9, in which the gearwheel or like transmission means is provided with an annular groove which has a radially extending recess into which the pin means can be received in order to arrest the gearwheel or like transmission means.

11. A piercing press according to claim 2 or 3, in which said driving means comprises a ring gear which is guided slidingly in relation to the turret plate and which encircles the turret plate, the ring gear on the one hand being in engagement with the gearwheels or like transmission means and on the other hand being in engagement with a gearwheel of a motor.

12. A piercing press according to claim 11, in which the ring gear is toothed internally and externally.

13. A piercing press according to claim 11 or 12, in which the ring gear is provided with annular guide means which is secured on both sides axially in a correspondingly shaped groove of the turret plate.

14. A piercing press according to any of claims 11 to 13, in which the ring gear is guided coaxially in relation to the turret plate.

15. A piercing press according to any of claims 11 to 14, in which the motor couplable to the ring gear is equipped with a locating brake.

16. A piercing press according to any of claims 4 to 7 or 11 to 15, in which the motors are numerically controllable.

17. A piercing press formed as a piercing press with a single-head station, the press comprising holder means for a tool comprising at least a punch and a matrix die, wherein the tool is displaceable at least partially perpendicular to the surface of a workpiece to be machined and is mounted for rotation about its longitudinal axis through any angular step under the action of driving means, wherein the tool is additionally mounted to be displaceable in a direction parallel to the plane of the workpiece, and wherein the driving means can be coupled to the tool.

18. A piercing press according to claim 17, in which the driving means comprises a carriage which is associated with the lower part or the upper part of the tool, the carriage carries a motor for rotation of that tool part, and the motor is connected to the tool part by gear means either directly or through the intermediary of a sleeve.

19. A piercing press according to claim 18, in which the carriage is displaceable in a plane parallel to the plane of the workpiece and parallel to the guide of a guide block carrying the associated tool part, and in which the gear means is preferably formed as a toothed belt drive.

20. A piercing press according to claim 19, in which the carriage can be coupled to the guide block and the carriage is equipped with arresting means.

21. A piercing press according to claim 20, in which the arresting means comprises a piston-cylinder unit which is equipped with two piston rods for arresting the carriage on the one hand and for coupling it to the guide block on the other hand.

22. A piercing press according to claim 21, in which the piston-cylinder unit is formed such that when the carriage is uncoupled from the guide block the carriage is arrested in relation to the machine frame of the piercing press.

23. A piercing press according to any of claims 18 to 22, in which the carriage is provided with a piston-cylinder unit which cooperates with a mechanism arranged to lock the tool in a locatable angular position.

24. A piercing press according to claim 23, in which the mechanism comprises a lever which is provided with a latch arresting the rotational movement of the tool and in which the lever is under the bias of spring means.

25. A piercing press according to claim 24, in which the latch can be brought into engagement with toothing on the tool or on a sleeve guiding the tool.

26. A piercing press according to any of claims 19 to 22, in which the guide block is equipped with a coupling element for displacement in a plane parallel to the plane of the workpiece.

27. A piercing press according to any of claims 18 to 26, in which the motor or motors is/are numerically controllable.

28. A piercing press substantially as hereinbefore described with reference to Figures 1 to 4, Figures 5 to 12 or Figures 13 and 14 of the accompanying drawings.