LOCKING DEVICE FOR SECURING A TOOL IN A MACHINE

Abstract: Locking device for securing a tool in a machine, such as, for example, a bending machine, a pressing machine or the like, where the tool (5) is secured in a tool holder (1) in the machine. The tool (5) has a shaft part (6) which is accommodated in a tool-receiving channel (2) in the tool holder (1) and is secured herein partly by means of a safety arrangement which cooperates with a keyway (3) in the tool holder (1), and partly by means of a locking system. The safety arrangement comprises a hook (12) which is pivotally suspended in an intermediate part (7) of the tool (5). The hook (12) has a latch part (14) which can engage in the keyway (3) when the shaft part (6) of the tool (5) is mounted in the tool holder (1), and in such a manner that the engagement of the hook can easily be released.

Description: LOCKING DEVICE FOR SECURING A TOOL IN A MACHINE The invention concerns a locking device for securing a tool in a machine such as, for example, a bending machine, a pressing machine or the like, where the tool, e.g. a bending tool, a press tool or the like, is secured in a tool holder in the machine. The tool has a shaft part which is accommodated in a tool-receiving channel in the tool holder and is secured herein partly by means of a safety arrangement which co-operates with a keyway in the tool holder and partly by means of a locking system. A locking device of this kind is known from EP patent publication no. 494 714, where the locking device is used to secure a press tool in a power press, where an upper press tool and a lower press tool can move towards each other for the processing of a material which is placed between the two press tools. With this known apparatus, the locking device can be used for securing both the upper and the lower press tool. The known locking device comprises both a safety arrangement and a locking system. The safety arrangement secures the press tool immediately upon this being placed in the tool holder, after which the locking system which, e.g., can be of a mechanical, pneumatic, electrical or hydraulic type, can be activated so that the press tool is clamped in the tool holder. The system works in a corresponding manner when the press tool is to be removed, in that the locking system is first deactivated so that the press tool is secured solely by the safety arrangement. Hereafter, the safety arrangement can be released manually so that the press tool can be taken out. An advantage with this known arrangement is thus that the press tool can be inserted manually in a relatively simple manner and possibly moved manually until the correct position is found, after which the actual securing of the tool is effected by means of the locking system. The same applies when the press tool is to be removed, in that the clamping is first released by means of the locking system, after which the press tool is released manually by means of the safety device. The known safety device consists of a spring-loaded pawl which can be displaced in a hole transversely to the shaft part of the tool, a release button which can similarly be displaced in a hole transversely to the tool, and a connecting link which can transfer the movement from the release button to the spring-loaded pawl. When the shaft part of the tool is inserted into the tool holder, the spring-loaded pawl can engage in the keyway in the tool holder so that the tool is secured. When the tool is to be removed, the release button, which is disposed in an intermediate part of the tool, can be pressed in, in that the connecting link hereby transfers the movement to the spring-loaded pawl which is thus released from its engagement with the keyway. Consequently, with this known technique use is made of a relatively large number of individual parts for the safety arrangement, the result being that relatively great friction arises in this when it is activated. The safety arrangement can thus be difficult to release, especially when this involves an upper tool which after deactivation of the locking device is secured solely by the safety arrangement, and which thus in practice hangs in the pawl or the pawls. Since the pawl or pawls must be displaced linearly in order for the engagement with the keyway to be released, there will be quite great friction between the pawls and the keyway over the whole movement of the pawl or the pawls. However, this friction can be reduced if the user lifts up the tool at the same time, but this can place quite a strain on the user, in that use is often made of tools which are of a considerable weight. With the known technique, use is made of a locking system which similarly employs parts which move linearly for the clamping of the tool, in that a number of pins are provided which can be moved forwards and backwards in the holes in a locking system, in that in their displaced-forward position they are pressed in against the tool which is thus secured. In practice, with the use of this known system there will be certain limitations with regard to the use of tools, in that tools of a length which is less than the distance between two pins in the locking system can not be placed at any random position in the tool holder, but must be placed in a position in which it can be secured by a locking pin. An object of the present invention is to provide a locking device with a locking system and a safety device which is relatively simple in construction and which is easier to operate than the known system. This is achieved in that the safety device comprises a hook which is suspended in a pivotal manner in an intermediate part of the tool, said hook having a latch part which can engage in the keyway when the shaft part of the tool is mounted in the tool holder. It is hereby achieved that use is made solely of a single movable element, i.e. the hook, whereby the friction between fixed and moving parts in the arrangement is considerably reduced. At the same time, since the hook describes a turning movement, it is achieved that the latch part of the hook will be lifted free of the keyway in the tool holder immediately after the initiation of the turning movement, so that there will no longer be any friction in relation to the keyway when the user merely holds the tool at the same height. In order to reduce the friction in the safety device, it is thus not necessary, as is the case with the known arrangement, to effect a straining lift up- wards. Therefore, the safety device will be easier to release than with the known technique. With an expedient embodiment, such as disclosed in claim 2, the axis of rotation for the hook is placed in such a manner that the friction which exists between the latch part of the hook and the keyway is more or less equalised by the horizontal force which, due to the pull of gravity on the tool, will seek to draw the latch part free of the keyway. It is hereby achieved that a slight influence will be sufficient to release the securing of the tool by the hook. With a further embodiment, as disclosed in claim 3, the one end of the hook is configured as a release arm, and the axis of rotation for the hook is disposed between the release arm and the latch part. The release arm ca be influenced by the intermediate part of the tool, e.g. by a part of the release arm extending out through the recess in the tool's intermediate part, or in that a part of the release arm can be influenced through the recess, e.g. by means of a tool. Finally, the end of the release arm can lie more or less flush with the intermediate piece but, however, it must be positioned so that the user can influence the release arm with a finger. The safety device can thus be released by pressing the release arm in against the tool, whereby the latch part will be moved out of engagement with the keyway and into the shaft part of the tool. Alternatively, the locking device can be configured as disclosed in claim 4, in that the release arm is disposed between the axis of rotation for the hook and its latch part, e.g. by being configured as an operating button or the like. This operating button will thus be able to be operated, i.e. pressed in, from the front of the tool, i.e. that side through which the latch part of the hook projects. With this embodiment, it is thus possible to form the recess in the tool in which the hook is disposed exclusively from the front of the tool. Also with this embodiment, the release arm can be configured so that it projects out from the intermediate part and can be operated directly, or it can be configured so that it lies flush with or under the surface of the inter- mediate part so that it can be operated by the user pressing a finger or possibly a tool into a cavity or an opening. As disclosed in claim 5, it can be expedient for the hook to be connected with a spring which will ensure that the latch part of the hook extends out through the recess in the shaft part when the release arm is not influenced. Moreover, this spring will exercise that force which must be overcome to release the hook when the locking device is configured as disclosed in claim 2. By suitable dimensioning, it is thus possible to closely determine that force which is necessary to release the hook. In accordance with another expedient embodiment which is characterised in claim 6, a recess for the hook can comprise a part which serves as a stop for the turning movement of the hook, so that the latch part can not be moved too far outside the shaft part. If the hook is further configured as disclosed in claim 7, whereby the latch part of the hook has an inclined surface, it is achieved that the tool can be inserted directly in the tool holder, in that due to the inclined surface the latch part upon being inserted will be pushed into the shaft part and slide into engagement with the keyway at the correct position. As disclosed in claim 8, it can be expedient for the tool to be provided with a longitudinal locking groove in which a locking hook of a locking plate can enter into engagement and thus establish the clamping of the tool. As disclosed in claim 9, the locking plate can be arranged so that it can tilt around a pivot point, so that the locking hook which is disposed on the lower part will engage with the locking groove when the upper part of the locking plate is influenced by an activating element, which can be a highly- flexible hose. With this hose, a turning movement of the locking plate is achieved in a simple manner. The flexible hose will influence the locking plate uniformly over its length and, when the pressure is removed from the hose, very little force is required to induce the locking plate to move back in the open position. The use of hydraulic cylinders and the like is hereby avoided, which among other things can be an advantage in cases where it is desired to avoid any form of oil escape, in that the flexible hose can be activated with e.g. compressed air or a liquid which is not contaminating. Moreover, with this embodiment it will be an advantage that use can be made of tools of any random smaller length, and that these tools can be placed in a random position in relation to the length of the locking plate. Furthermore, as disclosed in claim 10, a return spring can be disposed in connection with the locking plate, so that when the activation element is deactivated, the locking plate is drawn out of its engagement with the lock- ing groove, whereby the clamping of the tool is released. In cases where the securing of longer tools in the tool holder is required, it can be expedient as disclosed in claim 11 to provide the tool with two or more uniformly disposed hooks, so that the tool is safely secured until the clamping is effected with the locking system. Finally, as disclosed in claim 12, keyways can be configured in both sides of that channel in the tool holder which accommodates the shaft part of the tool. It is hereby achieved that a choice can be made between two different positions of the tool (turned 180° in relation to each other), which is of special significance when the tool is not symmetrical in relation to a centreline for the tool holder. In the following, the invention will be explained in more detail with reference to the drawing, where fig. 1 shows a cross-section of a tool holder and a bending tool which are secured to each other by means of a locking device according to the invention, fig. 2 is a perspective view of a bending tool with a hook configured according to the invention, which is disposed in a recess in the bending tool, fig. 3 is a perspective view of a locking plate for use in con- nection with the locking device, fig. 4 shows an alternative embodiment of a hook, similarly shown in perspective, fig. 5 shows the forces which influence the latch part of the hook when this is used in an upper tool which is suspended in a tool holder, fig. 6 shows a cross-section corresponding to fig. 1 , but with an alternative embodiment of a hook and a bending tool, and fig. 7 shows a cross-section corresponding to fig. 1 , but where there is also illustrated a securing of the locking plate to the tool holder. In fig. 1 there is seen a cross-section of a tool holder 1 in which a tool is mounted by means of the invention. In the example shown, the tool is a bending tool 5. The shown tool with tool holder form part of a not-shown machine as an elongated part which, for example, under a certain pressure can be moved downwards towards an underlying counter-part which can either be mounted in a fixed manner or possibly be moved upwards. The underlying counter-part can, for example, consist of a tool holder mounted with a tool corresponding to that shown in fig. 1 , but turned 180° so that the tool faces upwards. The two tools, which are thus secured in each their tool holder 1 , can be identical, but can naturally also be different, all depending on the actual use of the machine. For example, such a machine can be used for the forming of material under pressure, especially sheet material, in that the machine can e.g. be a power press or a bending machine as shown in fig. 1. The tool holder shown in fig. 1 has a longitudinal channel or groove 2 which is used to accommodate the tool 5, a side part of said longitudinal channel being configured with a keyway 3 which, as will be described later, is used to secure the tool 5. In the shown example, the keyway 3 is shown as a channel with a rectangular cross-section, but the keyway can be configured with any other suitable shape. The tool 5 consists of a shaft part 6, an intermediate part 7 and a foot part 8. The foot part of the tool is determinative for the function of the tool, and in the shown example is configured as a bending blade which can be used, for example, for the bending of sheet metal material, but it will be obvious that the tool can be configured with foot parts suitable for any form of pressing, bending, shearing, blanking operations and the like. The shaft part 6 of the tool is configured in such a manner that it can be inserted with a good fit in the tool-receiving channel 2 in the tool holder 1. As is shown on fig. 2, which shows a tool 5 in perspective, the shaft part has a top surface 6a which abuts up against the bottom of the tool-receiving channel 2 or is possibly at a distance from this bottom, and a first side surface 6b and a second side surface 6c which lie up against the sides in the tool-receiving channel 2. Moreover, in connection with the shaft part there is an auxiliary support surface 6d which abuts up against an underside of the tool holder. As shown in fig. 2, an undercut 6e is provided between this auxiliary sup- port surface 6d and the first side surface 6b of the shaft part. This undercut is provided for reasons of production, in that it can otherwise be difficult to produce the two adjoining surfaces 6b and 6d so that a perfect inside angle of 90° is formed. With the shown configuration, the two surfaces 6b and 6d are able to be brought in tight contact with the corresponding right-angled part of the tool holder, such as shown in fig. 1. Providing that the top surface 6a can abut against the bottom of the tool-receiving channel 2, the auxiliary support surface 6d can possibly be omitted. In the shaft part 6 and in the intermediate part 7 of the tool there is provided a recess 9 which is configured substantially as a slot which extends parallel with the plane of the drawing in fig. 1. In the shaft part of the tool, this recess opens out in the second side surface 6c, and on the opposite side of the tool the recess opens out in the intermediate part 7. In this recess there is mounted a hook 12 which at its one end is configured as a latch part 14, and at its other end is configured with a release arm 15. The hook is also provided with a hole 13 which is used for suspending the hook in the recess 9, in that a pivot pin or axle is led through this hole 13 and is suspended on each side of the recess 9. In the tool 5 there is also provided a spring 16 which influences the hook 12 so that the latch part 14 will be pressed into the keyway 3 when the tool is inserted into the tool holder. As shown in fig. 1 , this spring 16 can be a helical spring which is retained with its one end in a blind hole in the tool, and which with its other end influences the release arm 15. Finally, in the shaft part 6 of the tool there is provided a stop 10 for the hook, this stop being configured in the second side surface 6c immediately under the latch part 14, but which can be placed in other suitable ways. This stop 10 functions as an end stop for the rotating movement of the hook, and thus prevents the latch part 14 from moving too far out of the shaft part 6. The locking device also comprises a locking system which comprises a locking plate 20 which extends along the tool holder 1 as shown in fig. 1. This locking plate 20 is mounted on the tool holder 1 in such a manner that it can tilt or rotate around a pivot point 21 , such as indicated in fig. 1. The lower part 24 of the locking plate has a locking hook 25 which can grip in under the tool holder 1 and in a locking notch 11 in the tool 5, which locking notch 11 is shown in fig. 2. At the top, the locking plate 20 stands in connection with an activation element 26 which can move the uppermost part of the locking plate in relation to the tool holder 1 , so that the locking hook 25 can be pressed into the locking notch 11. As shown, this activation element can, for example, consist of a tubular element 26 which is placed in a recess 4 in the tool holder. This tubular element, which is of a highly flexible type, is placed between the tool holder 1 and the locking plate 23 in such a manner that in the inactivated state it is pressed more or less flat, so that when influenced pneumatically or hydraulically it expands in circumference and presses the upper part 23 of the locking plate away from the tool holder. Conversely, when the air or hydraulic pressure is removed from the tube, it is compressed again, which is effected by means of a return spring 27 which, for example, can be a leaf spring which is placed in a recess or a notch in the tool holder 1 between this and the lower part 24 of the locking plate. As the activation element, use can be made, for example, of a tube of the type which is normally used as e.g. a fire hose. As mentioned, in fig. 2 is shown the position of the locking notch 11 on the tool 5, in that the locking notch is shown configured with sloping side surfaces which correspond to the shape of the locking hook 25 on the locking plate. Fig. 2 also shows the positioning of the hook 12 in the manner in which this is mounted in the recess 9. It is also shown that immediately below the latch part 14 of the hook and in connection with the recess 9 there is configured a recess 9a which extends in the longitudinal direction of the tool 5. In this recess, an element can be inserted which can constitute the stop 10 for the hook 12. Finally, it is shown that the hook 12 is provided with a locking notch 17 which allows the locking hook 25 of the locking plate to engage with the locking notch 11 without influencing the hook 12, such as this is also seen in fig. 1. In fig. 3 the locking plate 20 is shown in perspective, and it is seen that holes 22 are provided between the upper part 23 and the lower part 24. In the shown example, two holes are provided. These holes are used in the suspension of the locking plate, so that this can tilt around the pivot point 21 , which is marked in fig. 7. Fig. 4 shows an alternative embodiment for the hook 12, this embodiment distinguishing itself from that shown in figs. 1 and 2 simply by the latch part 14 being configured as a strip-like part with a breadth which is considerably greater than the breadth of the hook 12. With this embodiment, there is thus achieved a better grip in the keyway 3. However, from the point of view of production technique, this embodiment requires a more complicated configuration of the recess in the tool 5. Furthermore, with this embodiment a better control of the hook in the keyway 3 is achieved when a suspended tool is displaced sideways, e.g. in order to position the tool in the correct place in the machine. With this embodiment, it can not so easily occur that the hook tilts over in the keyway and possibly get stuck. Alternatively, special provision must be made to control sideways movements of the hook, e.g. by configuring the recess 9 in such a way that it serves as a guide for the hook, for example by having a breadth at certain places which corresponds precisely to the breadth of the hook, or by the hook being precisely controlled by the pivot pin or axle with which the hook is suspended, possibly in combination with the configuration of the recess 9. In fig. 5 are illustrated those forces which work on the hook 12 and especially the latch part 14 when the hook secures a tool in an upper tool holder. The pivot axis for the hook is thus indicated at the point 13, and the engagement point for the latch part 14 in the keyway 3 is indicated at point 14'. The point of engagement 14' can, for example, consist of the outermost edge of the keyway 3 adjacent to the tool-receiving channel 2 or of the point of the latch part, providing that it is this which first and foremost has contact with the keyway 3. At the pivot point 13, the hook will be influenced by the force of gravity F g on the tool. This force will similarly work vertically downwards at the point 14', but since the point of engagement 14' is not lying vertically over the point 13, there will be a force F on the latch part which from the point of engagement 14' is directed towards the pivot point 13. As shown, this force can be divided into two components at right-angles to each other, i.e. F g which works vertically downwards and F gv which works horizontally. The horizontal distance between the pivot point 13 and the point of engagement 14' is indicated with the letter a, and it is seen that the greater the distance a, the greater will be the force F and herewith F gv . The point of engagement 14' is also influenced by a frictional force F μ .which in magnitude is equal to F g times the statistical coefficient of friction μo, and which works in the direction opposite to F gv . The frictional force Fμ will thus be independent on the distance a, while the oppositely-directed force F gv will increase with the distance a. When F gv is greater than F μ , the latch part of the hook will be moved out of the keyway 3 without further influence from outside. Therefore, the distance a can be dimensioned so that it is less than or equal to that distance where F gv is equal to F μ . When F gv and F μ are equal, no force or only insignificant force is required on the hook to bring this out of its engagement with the keyway 3. The spring 16 will thus also serve to determine that influence which is required to induce the hook to turn out of engagement, for a suitably comfortable level for the user, and also, especially when the two above-men- tioned forces F gv and F μ are approximately the same, to ensure that the hook is not unintentionally brought out of engagement by an insignificant force. The advantage with the arrangement is that the manual force which must be applied in order to release a hook in practice is the same, regardless of the spatial orientation or physical weight of the tool. In fig. 6 is shown a cross-section of a bending tool and a tool holder corresponding to fig. 1 , but with an alternative configuration of the hook and the bending tool. Individual parts which are configured in the same way as shown in fig. 1 are indicated with the same reference numbers as in fig. 1 , and therefore they will not be discussed in more detail here. The hook, which is indicated by 12', differs from that which is shown in fig. 1 , in that here the release arm 15' is not configured as a part which extends from the axis of rotation 13 towards the opposite end of the hook in relation to the latch part 14, but on the contrary extends mainly in the same direction as that end of the hook where the latch part 14 is disposed. The significance of this is that when being released, the release arm 15' can be suitably influenced from the front, in that it can thus be pushed in towards the intermediate part 7 of the tool. The spring 16 will thus also be placed differently, in that as shown in fig. 6 it can be placed in a blind hole immediately behind the release arm 15'. The release arm can be configured as a separate part which is rigidly connected to the remaining parts of the hook, but can relatively simply be configured as a part of the hook's connection part between the axis of rotation 13 and the latch part 14, in that this merely involves the placing of some form of operating button on the front of the hook, such as shown in fig. 6. A further advantage of this embodiment is that the recess 9 in the tool, in which the hook 12' is disposed, can be configured exclusively from the front of the intermediate part 7 and shaft part 6 of the tool, unlike the configuration in fig. 1 , where machining must normally also be carried out from the rear of the tool. In connection with the mounting of the hooks 12 or 12' in a tool, it must be mentioned that the hooks can be placed in the end pieces of a tool, in that the provision of a recess can thus be effected solely from the end of the tool. When a hook is placed in such a recess 9, the hook can be secured by a separate component which is fastened to the tool and prevents the hook from falling out. This can thus involve a plate which wholly or partly covers the recess 9 in the end piece of the tool. The suspension of the locking plate 20 on the tool holder 1 is illustrated in fig. 7, which corresponds to fig. 1 but where the section is taken at a place where a securing element for the locking plate is provided. Reference numbers are shown only for the most important of the elements already discussed, i.e. the tool holder 1 , the tool 5, the hook 12, the stop 10 and the spring 16 for the hook, the locking plate 20, the hole 22 in the locking plate and the activation element 26. A bolt 30 through the hole 22 in the locking plate is secured in the tool holder 1 , in that the bolt is surrounded by a bush 31. As shown, the hole 22 is configured with two diameters, i.e. partly an inner diameter and partly an outer diameter which is greater than the inner. In that area of the hole 22 where this has an outer greater diameter, the bush 31 has an annular recess 32. Between the head of the bolt 30 and the bush 31 there is provided a tension washer 33 which at the same time secures an outer slide piece 34 and an inner slide piece 35 against the annular part of the hole 22 be- tween the larger and the smaller diameter. The outer 34 and the inner slide piece 35 are configured with co-operating surfaces which are configured with a cross-section in the form of part of a circular arc, so that the two slide pieces can be moved in relation to one another. The locking plate 20 can thus describe the turning movement in that the inner slide piece 35, which turns together with the locking plate 20, during its movement can move into the annular recess 32 in the bush 31. When a tool 5 is to be mounted in the tool holder 1 , the tool is manually placed opposite the tool-receiving channel 2, and the shaft part 6 is introduced into the channel. When the inclined surface on the latch 14 makes contact with the locking hook 25 on the locking plate 20 and/or the lower edge of the tool holder, the hook 12 or 12' will be turned against the spring pressure from the spring 16 so that the latch part 14 will be pushed into the shaft part of the tool. As will be seen in fig. 1 , the locking hook 25 on the locking plate 20 is also provided with an inclined surface, which will further facilitate this movement. When the shaft part 6 of the tool has been pushed so far into the channel 2 that the under part of the latch part 14 is opposite the lowermost edge of the keyway 3, the latch part 14 will be pushed into the keyway 3 by the spring 16, so that the tool 5 is now secured in the tool holder. When in this position, the tool can be displaced in the longitudinal direction of the tool holder until the desired position is found, in that the latch part 14 can be displaced in the longitudinal direction of the keyway. When the tool is in the desired position, the activation element 26 is activated so that the lower part 24 of the locking plate 20 is turned in towards the tool and the locking hook 25 is pressed into the locking notch 11. The locking hook 25 and the locking notch 11 can be configured so that the tool is pressed into the tool holder 1 in such a manner that the auxiliary support surface 6d and/or the top surface 6a of the shaft part 6 is pressed against the corresponding parts of the tool holder 1. At the same time, the first side surface 6b of the shaft part will be pressed against the corresponding side surface in the tool-receiving channel 2, so that the position of the tool is precisely determined in relation to the tool holder. When the tool 5 is to be removed from the tool holder 1 , the activation ele- ment 26 is deactivated, whereby the locking plate 20 will be turned by the return spring 27 so that the locking hook 25 is moved out of its engagement with the locking notch 11. Hereafter, the tool is held in the tool holder only by the engagement of the latch 20 with the keyway 3, which is of special significance when the tool holder is one which has downwards-facing channel 2 for receiving the tool, in that here the force of gravity will naturally seek to draw the tool out of the channel. The tool 5 can hereafter be handled manually, in that pressing on the release arm 15 or 15' will release the engagement of the latch part 14 from the keyway 3, so that the shaft part 6 of the tool can be led out of the channel 2. As mentioned, the disclosed locking device comprising the locking system and the safety arrangement can be used both for a tool holder with a downwards-facing channel 2 and a tool holder with an upwards-facing channel 2. Moreover, one or more tools can be accommodated in a channel 2, in that the tools can be inserted in the tool holder in extension of one an- other. In a tool 5 there can be configured one or more recesses 9 with associated hooks 12 or 12'. However, if a tool is to be inserted and removed without difficulty by only one person, it is expedient that at the most there are two hooks per tool. The locking plate 20 can be of such a length that it corresponds to the whole length of the tool holder 1 , in that the advantage achieved hereby is that a tool of a smaller length than the whole of the tool holder can be inserted, secured and locked at any random place along the tool holder. Use can be made, however, of locking plates of a smaller length, and such locking plates of a smaller length can be brought together singly to form a desired length. It must also be mentioned that use can be made of other types of locking systems in connection with the safety arrangement than the kind described above which use a pivotal locking plate. The safety arrangement disclosed can thus also be used in connection with locking systems which use linear- ly-displaceable locking cylinders and the like for the locking of a tool when this is secured by means of the safety arrangement. Finally, the tool-receiving channel 2 in the tool holder can have a keyway 3 in both ends of the channel, so that the tool can be inserted in two different positions. With such a configuration, a locking notch 11 must similarly be configured on each side of the tool for the securing of the tool by means of the locking plate 20.

Claims: CLAIMS . Locking device for securing a tool in a machine such as, for example, a bending machine, a pressing machine or the like, where the tool (5), e.g. a bending tool, a press tool or the like, is secured in a tool holder (1) in the machine, in that the tool (5) has a shaft part (6) which is accommodated in a tool-r ceiving channel (2) in the tool holder (1) and is secured herein partly by means of a safety arrangement which co-operates with a keyway (3) in the tool holder (1), and partly by means of a locking system, characterized in that the safety arrangement comprises a hook (12, 12') which is pivotally mounted in an intermediate part (7) of the tool (5), said hook (12) having a latch part (14) which can engage in the keyway (3) when the shaft part (6) of the tool (5) is mounted in the tool holder (1 ). 2. Locking device according to claim 1, cha racterized in that the friction in the safety arrangement is wholly or partly equalised by placing the pivot axis (13) for the hook (12) in the tool at such a horizontal distance (a: fig.1 and 5) from the poin' of engagement (14') of the latch part (14) in the keyway (3) that a horizontal frictional force (F μ ), which works between the keyway (3) and the latch pan (14), is substantially neutralised by an oppositely-directed force (F gv ) on the latch part which is brought about by the pull of gravity on the tool. 3. Locking device according to clain 1 or 2, characterized in that the hook (12) is pivotally suspended around a pivot axis (13) which is disposed between the latch part (14) for ne hook and a release arm (15) for the hook, in that the latch part (14) is disposed in the area for an opening out of a recess (9) in the shaft part (6) oi the tool, and in that the release arm (15) is disposed in the intermediate par. (7) of the tool. 4. Locking device according to claim 1 or 2, characterized in that a release arm (15') for the hook (12') is disposed in the intermediate part (7) of the tool between a pivot axis (13) for the hook (12') and the latch part (14) for the hook, in that the release arm (15') is possibly coincident with a connection link between the hook's pivot axis (13) and latch part (14). 5. Locking device according to one or more of the claims 1-4, characterized in that the hook (12, 12') is connected with a spring arrangement (16) which influences the hook with a spring force around the pivot axis (13), so that the latch part (14) is influenced to move out through the opening-out of the recess in the shaft part (6). 6. Locking device according to one or more of the claims 1-5, cha racectlzed in that the tool (5), in connection with a recess (9) for the hook, comprises a part which functions as a stop (10) for the hook (12, 12'), so that the movement of the hook is restricted, especially the movement of the latch part (14) outside the shaft part (6). 7. Locking device according to one or more of the claims 1-6, ch a racte ri zed in that the latch part (14) of the hook has an outer surface which towards the top surface (6a) of the shaft part slopes inwards towards the shaft part (6). 8. Locking device according to one or more of the claims 1-7, cha racterized in that the tool is provided with a longitudinal locking notch (11) on the shaft part (6) or on the intermediate part (7), and that the locking system comprises a locking plate (20) which is pivotally suspended and has a locking hook (25) which can enter into engagement with the longitudinal locking notch, so that the tool (5) is locked securely in the tool holder (1). 9. Locking device according to claim 8, cha racterized in that the locking plate (20) has a lower part (24) on which the locking hook (25) is configured, and an upper part (23), in that between the upper part (23) and the lower part (24) there is a pivot point (21) for the locking plate (20), and in that the upper part (23) can be influenced by an activation element (26), which is in the form of a flexible hose which extends the whole length of the locking plate, so that the locking hook (25) is pressed into the tool's longitudinal locking notch (11). 10. Locking device according to claim 8 or 9, characterized in that the locking system comprises a return spring (27), preferably in the form of e.g. a leaf spring, which is placed between the lower part (24) of the locking plate and the tool holder (1), in that said return spring (27) can influence the locking plate (20) so that the locking hook (25) is moved out of the locking notch (11). 11. Locking device according to one or more of the claims 1-10, characterized in that the tool (5) comprises two or more hooks (12) which are of substantially the same configuration, and which are distributed along the longitudinal direction of the tool. 12. Locking device according to one or more of the claims 1-11, characterized in that the tool-receiving channel (2) contains a key- way (3) in both sides, in that each of said keyways can co-operate inde- pendently with the hook (12) or hooks of the safety arrangement.

Inventors: IVERSEN FLEMMING KETLER, IVERSEN, FLEMMING, KETLER
Applicants: IVERSEN FLEMMING KETLER, IVERSEN, FLEMMING, KETLER
Application year: 1999
Main classification: B21D37
IPC codes: B21D5