FIELD OF THE INVENTION

The present invention relates to a radial press, comprising a multiplicity of press members disposed around a press axis and capable of moving radially relative to the press axis, and a drive unit for moving the press members in the direction of the press axis or away from it, wherein the press members are made in multiple parts and respectively have a base jaw and a press jaw fixed exchangeably on it, the base jaws respectively comprise a radially inwardly disposed press-jaw bracing face as well as, adjacent hereto in circumferential direction, two side faces, and the press jaws bear respectively with a mating face on the press-jaw bracing face of the associated base jaw and have, protruding from the mating face, a fixation projection, which is inserted in a seat provided on the base jaw and cooperates with a locking device disposed there. Furthermore, the present invention relates to a radial-press system, which comprises a radial press, a press-jaw magazine for storing replacement press jaws in sets and a quick-change jig functioning for changing of press jaws all together.

BACKGROUND

In order to be able to machine differently dimensioned workpieces with radial presses, they can typically be retrofitted by equipping them with variously dimensioned press jaws in such a way that pressed shapes having different diameters may be performed with them. These (exchangeable) press jaws are fixed radially inwardly on the base jaws, which in turn can be moved by the drive unit radially relative to the press axis. The said fixation projections, which are provided on the press jaws for exchangeable attachment of the press jaws to the base jaws, and which protrude from the mating faces of the press jaws, are inserted in seats provided on the base jaws and cooperate with locking devices of the base jaws, are realized, for example, as pins, pegs or bolts protruding radially outwardly from the press jaws. This is the case regardless of the actual specific design of the radial press; in particular, radial presses based on the so-called hollow-piston design (see, for example, DE 10149924 A1, EP 2420332 A1, EP 1610915 B1) can be regularly constructed in retrofittable manner according to the described principle, as can radial presses according to the so-called yoke design (see, for example, DE 4135465 A1, DE 19912976 A1, DE 19817882 B4, EP 1252943 A1, DE 202016008097 U1, DE 202016100660 U1) and also radial presses in other designs, for example the so-called pressure-plate design (see, for example, DE 2844475 A1, DE 3611253 A1, DE 10047025 C2, DE 3331721 A1).

A widespread practice is placement of the press jaws on the base jaws by radial movement of the respective press jaws relative to the base jaw in question. In the process, the press jaws may be placed individually by hand (from radially inside) onto the base jaws. In contrast, during simultaneous exchange of all press jaws of the respective set (see hereinafter), the (simultaneous) radial movement of all base jaws and press jaws relative to one another is brought about by movement—corresponding to closing of the radial press—of the base jaws by means of the drive unit radially inward until the latching units snap into place. Demounting of the press jaws (individually or else in sets) takes place in the inverse direction, wherein the locking devices are unlocked appropriately for this purpose.

According to an alternative concept, the press jaws are mounted by being pushed axially onto the base jaws. For this purpose, the seats on the base-jaw sides for the fixation projections of the press jaws on the press-jaw bracing faces of the base jaws respectively extend in axial direction in slot-like manner up to each base-jaw front side, from which the mounting of the press jaws takes place.

As was already mentioned in the foregoing, the press-jaw set—typically comprising eight press jaws—may be handled as a whole for exchange of the press jaws, so that the complete press-jaw set stored in a corresponding magazine is inserted into the radial press or removed from this and stored in the magazine. This reduces not only the time needed in association with retrofitting of a radial press but also the risk of (improper) equipping of the radial press with press jaws of different types. For the said handling of all press jaws of a press-jaw set all together, a quick-change tool having a handle and a press-jaw holder is used, which holds the press jaws in a manner disposed uniformly concentrically around the tool axis.

Various quick-change jigs are known for the corresponding changing of all press jaws all together under radial movement of press jaws and base jaws (see hereinabove) relative to one another, i.e. for movement of the base jaws all together in the sense of closing of the radial press. In the simplest case, the quick-change jig together with the press-jaw set received on it can be freely positioned therein by the operator of the radial press (see, for example, U.S. Pat. No. 6,257,042 B1 and DE 20109212 U1). However, it is more comfortable for the operator when a kind of positioning aid is provided (see, for example, DE 202015002566 U1). It is particularly comfortable when, via centering elements corresponding to one another on the quick-change jig and mating pieces on the radial press, it is provided, for centering of the quick-change jig in the radial press, that the tool axis is aligned with the press axis and in addition the press jaws are positioned such that the joining means, corresponding to one another, of the press jaws and base jaws (i.e. the fixation projections and seats) are aligned with one another. Such is known, for example, from EP 1610915 B1 and EP 2420332 A1. The centering means disclosed here also act in the sense of reduced danger of damaging the pins, pegs, bolts or other fixation projections mentioned in the foregoing during mounting of the press jaws.

The present invention has an object of providing a radial press that is improved compared with the prior art, especially in terms of flexibility, namely in terms of the possible pairings of base and press jaws.

SUMMARY

This stated object is achieved according to the presently described invention in that the base jaws are respectively provided at their press-jaw bracing face with a channel-like recess, which extends from the seat (for the fixation projection of the respective press jaw) to one of the side faces of the base jaw and is open at it. Such channel-like recesses, which extend respectively from one side face of the base jaw in question to its seat ensure that the fixation projections of the press jaws project at least in the end regions or partly into the contour—defined by the respective press-jaw bracing face—of the respectively associated base jaw as early as during mounting—which takes place by a turning movement of the press jaws around the press axis—of the press jaws. During mounting of the press jaws, their fixation projections travel—by the said turning movement of all press jaws of the set all together around the tool axis—from the respective side face of the base jaw in question along the recess of the associated base jaw to the seat in question. The angle of rotation in question during the process is preferably approximately half of the pitch, i.e. for a radial press having eight press members, approximately between 20° and 25°, for example approximately 22.5°.

A particularly prominent advantage consists in that, for mounting of the press jaws, the respective distance between the press-jaw bracing faces and the mating faces of the associated press jaws may be smaller than that amount by which the fixation projections on the respective mating face protrude radially from the press jaws. During application of the invention, therefore, it is even possible, for a given radial press, to mount such press jaws (all together as a set) that, due to inadequate distance between the base jaws in a radial press open to the maximum, would at best be mountable individually in conventional radial presses. By application of the invention, it is even possible to achieve certain configurations, i.e. certain pairings of base jaws and press jaws, that in conventional radial presses are not even possible at all by manual mounting of the individual press jaws. Seen from another perspective, it can be deduced as an advantage of the invention that longer fixation projections than in the prior art may be used, thus permitting implementation of additional functionalities in the fixation projections (see hereinafter). Yet another advantageous effect of the invention consists in that, in comparison with the prior art, more precise matching of the fixation projections and associated seats to one another in terms of their dimensioning is possible, and so the axial offset of the press jaws relative to one another, observed in the prior art and caused by corresponding play between fixation projections and seats, may be greatly reduced. Compared with such radial presses in which the press jaws are mounted by being pushed axially onto the base jaws and the base jaws are provided for this purpose with receiving slots, which extend in longitudinal or axial direction, for the fixation projections of the press jaws, a quite decisive advantage of the invention consists in the much smaller weakening of the base jaws, specifically in that, in the inventive concept, the particularly stressed front-side end regions of the base jaws (namely in the particularly stressed middle plane), may be constructed in massive and intact manner.

The recesses characteristic for the inventive radial presses extend, according to a first preferred further development of the invention, exactly in circumferential direction. Thus recesses of the shortest possible length are achieved, thus resulting in only minimum weakening of the base jaws, and in addition are confined to the less heavily stressed middle region of the base jaws. In this case, mounting of the press jaws takes place by means of a strict two-stage movement (axial insertion at first, then turning in circumferential direction).

In typical constructional implementations of the present invention, the fixation projections of the press jaws are aligned, during axial insertion of the press-jaw set into the space bounded by the base jaws (while the radial press is opened), with the open spaces between respectively two base jaws adjacent to one another. In the case of more or less play-free guidance of the fixation projections into the open spaces in question through respectively the two base jaws bounding them, effective centering of the quick-change tool already takes place in such a way that its tool axis is aligned with the press axis.

The axial position of the quick-change tool together with the received press jaws, in which the second stage of mounting of the press jaws, i.e. the turning movement of the press jaws around the tool axis with displacement of the fixation projections into the recesses, is possible and is to be undertaken, may then be defined in particular by a stop (or several stops). In a particularly preferred configuration, such a depth stop (e.g. in the form of a disk) is provided on the quick-change jig and cooperate with the front sides of the base jaws. In this case, the disk in question may additionally act as protection against encroachment, which prevents anyone from reaching into the press-jaw installation space during the changing of press jaws and hereby contributes considerably to accident prevention.

In certain application situations, it may be advantageous when the base jaws are respectively provided, at that side face at which the respective recess opens, with a cutout extending from the opening of the recess to one of the front sides of the base jaw. Such peripheral cutouts, respectively provided in the region of the transition from the press-jaw bracing face to the side face in question of the base jaw, may function, so to speak, as “feeders” for the fixation screws at the openings of the recesses; they permit insertion of the press-jaw set together with fixation projections protruding into the contour defined by the press-jaw bracing faces even when the (other) open spaces between respectively two base jaws adjacent to one another are too narrow to receive the respective fixation projections. With appropriate dimensioning of the said cutouts, mounting or demounting of the press jaws is possible even when the radial press is completely or at least more or less closed, which may be advantageous for special applications using special press jaws.

Quite particularly preferably, such a cutout extending in axial direction to the front side of the base jaw (without connection to the recess) is also provided (in more or less mirror-image manner) on the opposite, second peripheral region of the press-jaw bracing face, i.e. in the transition region from the press-jaw bracing face to the second side face of the base jaw. In this case, the widening of the open space present between the base jaws and necessary for axial insertion of the press-jaw set in the press-jaw installation space for the fixation projections is distributed (more or less uniformly, depending on the constructional configuration in the individual case) over the two cutouts respectively disposed opposite one another. Thus optimum symmetry of the bracing of the press jaws on the base jaws can be achieved, and so, even in the case of extreme stress conditions, asymmetric deformation of the base jaws leading to tilting of the press jaws is ruled out. This favors fabrication precision, is protective toward material and thus acts in the sense of lengthening the useful life of the radial press.

Incidentally, the cutouts explained in the foregoing are able to take over the function of a depth stop described hereinabove, and so a separate stop is superfluous. This is so because, with suitable configuration, the inner ends of the cutouts (in cooperation with the associated centering projections) adjacent to the openings of the recesses effectively confine the axial insertion movement of the press-jaw set received on the quick-change tool exactly in a position in which the fixation projections are disposed opposite the openings of the recesses, and in this way the turning of the press-jaw set constituting the second stage of the insertion movement is possible.

In an alternative configuration, the cutout, explained in the foregoing, extending to one of the front sides of the base jaw in question, may even be provided not on that side face of the base jaw on which its recess opens but instead on the opposite side face. In this case, the recess of the adjacent base jaw respectively opens into the cutout or the cutout of a base jaw forms the “feeder”, to the recess of the neighboring base jaw in question, for the fixation projection of the press jaw to be mounted on the adjacent base jaw.

The radial depth of the recesses provided may be based on the respective requirements. In the interests of a construction of the base jaws that is as stable as possible, the recesses are preferably not deeper than is necessary for achievement of the advantages aimed at in the individual case. In this sense, the recesses are generally less deep than the seats for the fixation projections. In this way the mounting of the press jaws is typically concluded with a radial movement (albeit shorter than that known from known machines) of the base jaws and press jaws relative to one another, whether it be by a radially inwardly directed movement of the base jaws in the sense of closing of the radial press or else a radially outwardly directed movement of the press jaws (for example using a quick-change jig corresponding to the concept according to DE 20109212 U1). In the individual case, however, the depth of the recesses may also correspond to the depth of the seats, and so mounting of the press jaws is possible even without radial movement of the base jaws and press jaws relative to one another (for example, when the radial press is completely closed; see hereinabove). In this case, the locking of the press jaws on the base jaws takes place near the end of the turning movement.

The orientation, explained in the foregoing, of the recesses in circumferential direction represents a configuration preferably realized in typical application situations; however, it is not absolutely necessary. Subject to specific prerequisites, other profiles of the recesses may also be advantageous in the individual case.

Thus, for example, extension of the recesses respectively along a helical line may also prove favorable instead of orientation of the recess in circumferential direction. Depending on the dimensions (especially the axial length of the base jaws), it is also conceivable to continue the recess beyond its opening at the side face of the base jaw and into the adjacent base jaw (if necessary, up to its front side). Incidentally, even in the case of such recesses not oriented in circumferential direction, the peripheral recesses described hereinabove may be provided in order to achieve the explained advantages associated with them.

According to yet another preferred further development, at least two fixation projections of geometrically different construction and/or at least two seats of geometrically different construction are provided. By such geometric individualization of at least one fixation projection or at least one seat, it is possible to ensure that the press-jaw set can be mounted in the base jaws of the radial press only in a single, predefined position. This further development is applicable, for example, during use of a press-jaw set in which one of the press jaws is provided with embossing types for marking the workpiece, since the corresponding marking press jaw should always be mounted on the lowermost base jaw. A preferred exemplary embodiment consists in that the fixation projection of one of the press jaws has such a thickening that this fixation device is located not in the usual open spaces between respectively two base jaws of the (opened) radial press but only in the one single open space widened by a cutout (see hereinabove).

Yet another preferred further development of the present invention is characterized in that the locking device (respectively installed in the base jaws) exerts a radially outwardly directed preload force on the fixation projection cooperating with it. In this way the locking device pulls the respective press jaw radially outward for secure, play-free bearing on the press-jaw bracing face of the associated base jaw. Thus the reproducibility of radial pressing and consequent the fabrication accuracy of the radial press can be improved.

In view of easy retrofitting of the radial press, i.e. of particularly simple changing of press jaws, it is advantageous when a bore, through which the locking device can be unlocked, is provided respectively at the front side of the base jaw. In a radial-press system that comprises a radial press, a press-jaw magazine containing replacement press jaws stored in sets for their attachment to the base jaws of the radial press, and a quick-change jig permitting changing of the press jaws all together and having a handle and a press-jaw holder, such bores can be used in such a way that the quick-change jig is further provided with an unlocking arrangement of unlocking elements capable of being inserted at the front side into the bores of the base jaws, wherein the press-jaw holder and the unlocking arrangement of the quick-change jig can be turned relative to one another around a tool axis. In this way it is possible by means of the quick-change jig—during implementation of the present invention—to turn the press jaws relative to the base jaws in order to mount or demount them, wherein the unlocking elements provided on the quick-change jig simultaneously unlock the locking devices. It is particularly advantageous in this case when the press-jaw holder of the quick-change jig is connected to its handle in a manner to be turned together therewith.

However, the unlocking elements functioning for unlocking of the locking devices may also be constructed in the most diverse but otherwise suitable ways. Besides mechanically acting unlocking elements such as pins, bolts or the like, contactlessly acting unlocking elements, for example, are—given corresponding construction of the locking devices—also conceivable, such as, for example, such on a magnetic basis. Even such unlocking elements are an expedient part of an unlocking arrangement, which can be turned—around the tool axis—relative to the press-jaw holder.

Merely to avoid mistaken impressions, it must be mentioned that the base jaws, for their part, do not necessarily have to be constructed in one piece. Instead, they may also be constructed in multiple pieces, in that they respectively comprise an intermediate jaw, placed on a base-jaw basis, on which the press-jaw bracing face is constructed. Likewise, it must be mentioned that the press-jaw bracing faces and the mating faces indeed are typically constructed according to a circular-cylinder portion, but again this is not absolutely necessary, since even different geometric configurations of the separating faces between base and press jaws may prove to be favorable in the individual case. Furthermore, it must be pointed out that, within the meaning of the present invention, the indication according to which the press members are radially guided in a manner movably displaceably relative to the press axis is not to be understood as limitative in the sense of a purely radial movement in a plane perpendicular to the press axis; to the contrary, the press members, as is customary in particular in certain radial-press designs according to the pressure-plate concept, also experience a certain axial displacement during pressing, so that the movement of the press members may have an axial component in addition to the radial component during their approach to the press axis as well as during their removal from it. Incidentally, not only mechanical, especially interlocking and/or latching interlocks are conceivable as the interlocking device for the press jaws; to the contrary, the “locking devices” may also ensure fixation of the press jaws on the respective associated base jaws in other ways, for example, by clamping action, by magnetic forces or the like.

