This invention relates to a rotatable multi-tool holder which can be indexed about its rotational axis, and to a machine tool provided with such a rotatable multi-tool holder. The invention particularly, but not exclusively, relates to such a rotatable multi-tool holder provided with stamping, embossing or punching tools and to a punching and/or stamping or embossing machine provided with such a tool holder.

According to the present invention in one aspect there is provided a rotatable multi-tool holder which can be indexed about its rotational axis, comprising an outer casing having a longitudinal bore and which can be fixed in a tool hofder carrier, a bush member axially located and rotatably mounted in said bore for indexing rotation relative to said outer casing, a tool carrier member rotatable with said bush member and provided with a circular array of axially movable tools, and a non-rotatable axially-movable punch body located within the tool carrier for axially moving a tool when the tool is indexed to a predetermined location.

Preferably the punch body is provided with a circular array of resiliently loaded pressure pads, each pad bearing against one end of a tool of said circular array of tools except at said predetermined location, and at each indexed location of a tool except at said predetermined location means are provided for preventing axial movement of a tool during axial movement of the punch body.

The means for preventing axial movement of the tools which are not at the predetermined location may comprise pins extending transversely of the tools and fixed relative to the outer casing, each pin extending into the path of the associated tool or in the path of a member carried by the tool.

Preferably the punch body is provided at said predetermined location with an adjustable member which makes contact with an end of a tool located said predetermined location.

According to the present invention in another aspect there is provided a machi.-.e c ol provided with a tool holder carrier in the form of an indexible rot atable turret provided at one or more locations with a rotatable multi-tool holder as defined above.

The machine tool preferably includes a second indexible rotatable turret spaced from and parallel with the first indexible rotatable turret and indexible in sequence therewith, said second turret being provided at one or more locations with a rotatable platen or multi-die carrier, and means for sequentially indexing a said multi-tool holder and a said platen or multi-die carrier when they are aligned and located at a predetermined location.

Some embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a diagrammatic illustration of the front elevation of a machine tool, partly broken away, provided with rotatable multi-tool holders embodying the invention,

Figure 2 is a longitudinal section through a rotatable multi-tool holder provided with punches and a rotatable multi-die holder,

Figure 3 is a view taken in the direction of arrow 3 indicated on Figure 2, with the stripper removed,

Figure 4 is a view similar to that of Figure 2, on a reduced scale, showing the parts of the multi-tool holder in the punching positon.

Figure 5 is a longitudinal section through a rotatable multi-tool holder constituting a second embodiment and provided with marking tools, and a rotatable platen,

Figure 6 is a view taken in the direction of arrow 6 indicated on Figure 5 with the stripper removed, and

Figure 7 is a longitudinal section through another embodiment of a multi-tool holder and a rotatable multi-die holder. The machine tool 10 shown in Figure 1 comprises an upper casing 11 in which is rotatably mounted an Indexible upper turret 12, and a lower casing 13 having a bed 14 and a rotatably mounted indexible lower turret 15. the turrets 12 and 15 are synchronously rotated by an indexing mechanism

(not shown) which may be computer controlled. The upper turret 12 is provided with a circular array of tool holders

16 and at least one of the tool holders 16 comprises a rotatable multi-tool holder 17 which can be Indexed about its own axis when located at a work station 18. Three multi-tool holders 17 are shown in Figure 1. The tools in t s or each multi-tool holder 17 may comprise punching, stamping or embossing tools. Such multi-tool holders 17 will be described in greater detail later. Located at the work station 18 is a ram

19 which cooperates with the tool holders 16, 17 when they are located at the work station 18.

The lower turret 15 is provided with a circular array of platens and/or die holders 20. At least one of the platens and/or die holders 20 is rotatable about its own axis.

When a rotatable multi-tool holder 17 and a rotatable platen or multi-die holder 20 are located at the work station 18 and aligned one with the other they can be indexed about their own axis by an indexing mechanism (not shown) which can be computer controlled. it will be appreciated that all of the tool holders 16 may comprise rotatable multi-tool holders 20 and that all of the platens or die holders may comprise rotatable multi-die or multi-platen holders. The provision of one or more rotatable multi-tool holders 17 substantialy increases the number of tools which can be carried by the upper turret 12 compared with machine tools in which only single tool holders are provided on a turret.

Figures 2 to 4 illustrate one embodiment of a rotatable multi-tool holder 17 and one embodiment of a rotatable multi-die holder 20. The rotatable multi-tool holder 17 in this embodiment comprises an outer cylindrical casing 21 which is mounted in a bore 22 provided in the upper turret 12, the casing 21 having at its upper end a radially extending peripheral flange 23 which is fixed to the upper turret 12 by bolts 24. Rotatably mounted in the casing 21 is a bush 25 provided at its bottom end with a retainer plate 26 and at its upper end with a radially extending peripheral flange 27 having gear teeth 28 at its periphery. The gear teeth 28 are engaged by a worm gear 28a which is driven by any suitable means to rotatably index the bush 25. Located within the bush 25 is a tool carrier 29 having a cylindrical portion 30 which is keyed to the bush 25 by a key 31 which extends in an axial slot 32 provided in the bush 25. The tool carrier 29 has a transverse tool carrying portion 33 provided with a circular array of vertical bores 34 in which punching tools 35 are slideably received. Located within the tool carrier 29 is an axially movable punch body 36 provided at its upper end with an engaging portion 37 which when the tool holder 17is located at the work station 18 engages with the ram 19. The punch body 36 is provided with a circular array of recesses 38 which sre equal in number to and at the same spacing as the circular array of punching tocls 35. One of the recesses 38 is shorter in length than the others and houses a striker 39

which is engaged by a cap-screw 40 and which is provided with a ball bearing 41 acted upon by a spring 42. The striker 39 transmits theforce from the punch body 36 to the tool 35 which is axially aligned with the striker 39. The remaining recesses 38 each house a coil spring 43 which acts on a pressure pad 44 provided with a ball bearing 45.

Rotatably mounted on the bottom end of the punch body 36 by means of a shoulder screw 46 is stop ring 47 through which the ends of the tools 35 extend. Secured to the bottom end of the casing 21 by means of bolts 48 is a punch selector ring 49. Each of the tools 35 is provided with a transversely extending projection 50 and the ring 49 is provided with a circular array of inwardly radially extending stop pins 51 which are engaged by the projections 50. At the location corresponding to the tool 35 acted upon by the striker 39 there is no stop pin 51 and thus the tool 35 at this location can be moved downwardly by the striker 39. The tool carrying portion 33 is provided on its upper surface with a circular array of detents 52 and the punch body 36 is provided with a spring loaded ball 53 which seats in one of the detents 32.

Mounted on the stop ring 47 is a resilient stripper 54 which is retained thereon by a retainer plate 55 secured by screws 56. The resilient stripper 54 is provided with holes 57 through which the ends of the tools 35 extend.

The multi-die holder 20 consists of a cylindrical liner 58 which is received in a bore 59 provided in the lower turret 15 and is provided at its upper end with a flange 60 which Is secured to the lower turret 15 by bolts. A die holder body 61 is rotatably mounted in the liner 58 and retained therein by a ring 62 secured to the bottom of the body 61 by bolts 63. The body 61 is provided with a radially extending flange 64 provided at its periphery with gear teeth 65 engaged by a worm gear 66 which is driven by any suitable means in synchronism with the worm gear 28a. Secured to the upper end of the body 61 by bolts 67 is a die holder plate 68 provided with a circular array of different dies 69.

The rotatable multi-tool holder 17 and the multi-die holder 20 when they are located at the work station 18 are indexed simultaneously.

Rotation of the bush 25 is transmitted to the tool carrier 29 by the key 31 and thus the tools 35 are indexed to bring the desired tool 35 in alignment with the striker 39. The ball 53 locates the tool carrier portion 33 with

respect to the punch body 36. The die holder 20 is simultaneously indexed to bring the desired die 69 in line with the desired tool 35. The ram 19 is then actuated to move the punch body 36 downwardly. Upon downward movement of the punch body 36 the striker 39 effects downward movement of the desired tool 35 but the remaining tools 35 are prevented from moving downwardly by the respective stop pins 51 which are contacted by the projections 50. During such downward movement of the punch body 36 the springs 43 are compressed. As will be seen from Figure 4, the tool carrier 29 moves downwardly as does the stop ring 47 and the resilient stripper 54 and the desired tool 35 punches the workpiece 70. The resilient stripper 54 is compressed. Upon return movement of the ram 19 the punch body 36 is moved upwardly and the operative tool 35 is raised and the resilience of the stripper 54 strips the workpiece 70 from the tool 35.

Figures 5 and 6 illustrate a rotatable multi-tool holder 17 provided with a circular array of marking tools 72 instead of punching tools. The parts which correspond with the parts described with reference to Figures 2 to 4 are identified by similar reference numerals. In this embodiment the marking tools 72 are urged by compression springs 73 into contact with a plate 74 which surrounds the punch body 36, the plate 74 being acted upon by coil springs 75. The punch body 36 is provided with an adjustable striker pin 76 which enters a through hole 77 provided in the plate 74. The tool 72 located in line with the striker pin 76 is contacted by the striker pin 76. When indexing the tool carrier 29 the heads of the tools 72 slide on the plate 74 and when a tool 72 is aligned with the hole 77 it moves into contact with the striker pin 76 and the tool 72 which was previously aligned with the striker pin 76 moves back into contact with the plate 74. The bottom of the punch body is provided with a resilient damper 78. The tool 72 which is in contact with the striker pin 76 is moved downwardly by a small distance against the pressure of its spring 73 and its bottom end is thus lower than the remaining tools 72. Upon downward movement of the punch body 36 only the tool 72 which is in contact with the striker pin 76 will contact and mark the workpiece even though the remaining tools are also moved downwardly.

The platen 20 in this embodiment is indexible but it will be appreciated that a fixed platen may be provided on the lower turret 15.

Figure 7 illustrates a rotatable multi-tool holder which is similar to that shown in Figure 2 and the parts which correspond with those of Figure 2 are identified by similar reference numerals. In this embodiment the resilient stripper 54 is replaced by a mechanical stripper which comprises a rotatable stripper plate 79 having apertures 80 into which the ends of the tools 35 extend. The plate 79 is rotatably mounted on s shoulder screw 80 and acted upon by a coil spring 81. The plate 79 also carries coil springs 82 which have a clearance between the punch stop ring 47 and which prevent the plate 79 tilting. The tool holder operates in the same manner as described with reference to Figures 2 to 4. In this embodiment the multi-tool holder is indexed by an indexing key 83 instead of gears.

The multi-die holder as shown in Figure 7 consists of a rotatable body 84 provided with a circular array of different dies 85 and the body 84 has a bottom indexing ring 86 provided with an indexing key 87. The rotatable tool holders 17 and die or platens 20 can rotate through

360 degrees about their own axis and this rotation is accurately and precisely programmable. Turret punch presses are often an integral part of what is known as a Flexible Manufacturing System which includes a shear to a guillotine or shear the component parts of a nested sheet. That is to say, a mixture of different parts can all be punched from a single sheet of material. Due to optimisation of the programme and full utilisation of a sheet of material, the computer controlling the machine will nest the parts In the most economical way in a possible jig-saw pattern. The holes and apertures are then produced and the workpiece transferred to the shear for the components to be sheared from the sheet. Due to the fact that nesting of components is decided by the computer it is not easy to identify which component has been produced and the alpha-numeric indent tool of Figure 5 and 6 enables each part to be marked. Previously stamping tools have occupied too many stations on a turret but with the tool holder device shown in Figures 5 and 6 only one station of the turret has to be used.