Clamping jaw and clamping jaw system

Abstract

Clamping jaw (10) for a clamping jaw system (100) for clamping a workpiece with the following features: a. The clamping jaw (10) has a base jaw (20) and a top jaw (70) which can be placed on it in a coupling direction (4), wherein the base jaw (20) and the top jaw (70) are provided for joint displacement in a feed direction (2) during the clamping and unclamping of a workpiece, and b. the top jaw (70) has a clamping surface (72) for contact with a workpiece, and c. the base jaw (20) has a contact surface (30) on a top surface (26) and the top jaw (70) has a corresponding contact surface (80) on a bottom surface (76) for planar contact with the top surface (26) of the base jaw (20), and c. To lock the top jaw (70) onto the base jaw (20), the top jaw (70) has a locking recess (86) on its underside (76), which is formed by a depression transverse to the coupling direction (4), and d. the base jaw (20) has a receiving space (36) and a locking element (40) movable within the receiving space, which is movably received in the receiving space (36) between a release position and a locking position, wherein the locking element (40) is engaged in the locking recess (86) when the top jaw (70) is attached, and e. in the base jaw (20) a control shaft (60) is mounted, on which at least one eccentric area (62) is provided in a torsionally rigid manner, and f. the eccentric area (62) acts indirectly or directly on the locking body (40) during a rotational movement of the control shaft (60) and thereby presses the locking body (40) into the locking position in the locking recess (86), so that the top jaw (70) is thereby secured against separation from the base jaw (20).

Description

SCOPE OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a clamping jaw system for clamping a workpiece for the purpose of machining, and to a clamping jaw for this purpose.

[0002] Clamping jaw systems of this type feature multiple clamping jaws that are movable relative to each other for clamping and releasing workpieces. Each clamping jaw consists of a base jaw and a top jaw to which it is attached. The interchangeability of the top jaw allows for the use of jaws adapted to the workpiece, for example, top jaws with an optimal clamping surface for the respective workpiece, or specific top jaws for use as internal or external clamping devices.

[0003] In the production process, changing the top jaws is a regular occurrence. Current clamping jaws are not yet ideal in terms of the ease and safety of this change. In particular, existing systems require improvement when the top jaw change needs to be performed either manually or automatically. TASK AND SOLUTION

[0004] The object of the invention is to provide a clamping jaw system and clamping jaws for this purpose that allows for easy replacement of the top jaws.

[0005] For this purpose, a clamping jaw is primarily proposed, as well as a clamping jaw system with such a clamping jaw, in which the following design is implemented.

[0006] In a manner typical of the invention, a clamping jaw comprises a base jaw and a top jaw that can be mounted thereon in a coupling direction. Together, the base jaw and the top jaw form a clamping jaw that is immobile during operation and is displaced as a whole relative to a chuck in order to clamp or release a workpiece.

[0007] The actual application of a clamping force to the workpiece occurs, at least primarily, via the top jaw. For this purpose, the jaw has a clamping surface for contact with the workpiece.

[0008] To couple the top jaw to the base jaw, a contact surface is provided on one of the base jaw's upper surfaces. In this context, the terms "top" and "bottom" are not to be understood as referring to the sides facing up or down during operation. Rather, the top surface is defined as the side facing the top jaw, providing the primary contact area for the top jaw to engage. Similarly, the term "bottom" describes the side of the top jaw that faces the base jaw.

[0009] The top jaw has a contact surface on its underside, corresponding to the upper surface of the base jaw and its contact surface there, for a flat contact surface on the upper surface of the base jaw. When the top jaw is attached and secured, the top jaw and the base jaw are in contact with each other in the area of ​​these contact surfaces. The contact surfaces preferably extend in the plane defined by the feed directions of the clamping jaws of the clamping jaw system.

[0010] To secure the top jaw to the base jaw, the top jaw has a locking recess on its underside, formed by a depression perpendicular to the coupling direction. The base jaw is designed to allow the top jaw to be locked in place by means of this locking recess. For this purpose, the base jaw has a locking element that is movably arranged within a receiving space in the base jaw. The locking element can be moved within the receiving space between a release position and a locking position. When the top jaw is in the locking position, the locking element projects at least partially into the locking recess of the top jaw and thus prevents the top jaw from separating from the base jaw, provided it is locked in this position.

[0011] To lock the locking element in the locked position and to prevent the top jaw from unintentionally separating from the base jaw when the locking element is simultaneously deflected towards the release position, the invention provides for a control shaft to be rotatably mounted in the base jaw. At least one eccentric section, i.e., a section deviating from the rotational symmetry of the control shaft, is provided on the control shaft in a torsionally rigid manner. In particular, the eccentric section can be formed by providing a circumferential annular surface whose central axis is preferably offset from the axis of rotation of the control shaft.

[0012] The control shaft can be, in particular, a one-piece metallic control shaft on which the eccentric sections are directly integrated. However, a multi-part design is also possible, in which, for example, an eccentric ring is attached to a rotationally symmetrical control shaft.

[0013] When the control shaft rotates, the eccentric section rotates with it and acts directly or indirectly on the locking element. The eccentric section presses the locking element into the locking position in the locking recess, or, with continued or reverse rotation, allows the locking element to move back towards the release position, so that it can escape from the locking recess.

[0014] When the locking element is secured in the recess by means of the control shaft, the top jaw cannot be removed. The eccentric has a self-locking effect. Therefore, it is not possible to twist the control shaft by applying strong force to the top jaw in one direction of separation.

[0015] Preferably, the base jaw has a receiving recess on its upper surface. This receiving recess forms a depression that may be open on the side surfaces of the base jaw or, alternatively, open only on its upper surface. The receiving space, in which the locking element is movably arranged, adjoins this receiving recess. The locking element can therefore engage at least partially in the receiving recess. Preferably, the receiving recess and the receiving space of the locking element are separated from each other by a constriction through which the locking element as a whole cannot pass.

[0016] Corresponding to the receiving slot, a coupling extension is preferably provided on the top jaw, which, when the top jaw is attached, is located in the receiving slot of the base jaw. The locking recess is arranged on this coupling extension, so that the locking element can be pressed from the receiving space into the locking recess, thereby securing the top jaw when the movement of the locking element towards its release position is blocked.

[0017] The receiving chute and the coupling extension, by their shape, define the coupling direction between the top jaw and the base jaw. This coupling direction can be oriented orthogonally to the main contact surfaces on the upper side of the base jaw and the lower side of the top jaw, and / or orthogonally to the feed direction. Preferably, however, the angle between the feed direction and the coupling direction is not 90°. In particular, the angle is preferably between 60° and 85°.

[0018] This is particularly advantageous if the receiving chute is inclined relative to the feed direction in such a way that a contact surface within the chute forms an angle other than 90° with the contact surface on the top of the base jaw, preferably an angle between 60° and 85°. In such a case, the contact surface forms an acute angle with the contact surface. When the clamping jaw is pressed against this contact surface by the force exerted by the workpiece on the clamping surface of the clamping jaw, the clamping jaw is also pressed against the contact surface of the base jaw due to the inclination, thus moving it into the desired position. This facilitates the changeover, as the desired position of the clamping jaw on the base jaw is easily achieved.

[0019] Preferably, the receiving area of ​​the locking element is positioned opposite the contact surface in the receiving shaft, so that the force introduced into the top jaw via the locking element also presses the top jaw into the desired position. The aforementioned inclined contact surface accordingly ensures the correct positioning of the top jaw both when locking it and during operation.

[0020] The axis of rotation of the control shaft preferably extends parallel to the feed direction of the clamping jaw. This makes it possible to operate the control shaft from the outside of the clamping jaw. This is advantageous for both manual and automated operation, as the outside of the clamping jaw is particularly accessible.

[0021] Preferably, the control shaft has a non-circular actuating structure at an outwardly facing end, in particular in the form of a square or a hexagon. The control shaft can be rotated via this actuating structure, and the locked and released states of the top jaw can be achieved thereby.

[0022] The control shaft can act directly or indirectly on the locking element via the eccentric section. In the case of direct action, the locking element itself is in direct contact with the eccentric.

[0023] To allow the control shaft to be spaced away from the receiving area of ​​the locking element, the indirect effect of the control shaft on the locking body is preferred. In such a case, the base jaw has an intermediate element that rests against the eccentric area of ​​the control shaft and can therefore be displaced and, in particular, linearly moved by means of the control shaft. Preferably, the axis of rotation of the control shaft forms an angle of 90° with the displacement direction of the intermediate element.

[0024] The opposite end of the intermediate element rests against the locking body, at least intermittently. Preferably, an inclined contact surface is provided on the intermediate element for this purpose, against which the locking body rests and on which the locking body slides or rolls when the intermediate element is moved. Via the eccentric section and the intermediate element, the rotational movement of the control shaft causes the locking body to be pressed into the locking position and thus into the locking recess of the top jaw, thereby securing the top jaw.

[0025] The locking element itself can be a movable pin or have another shape with a fully defined orientation. However, the use of a rolling element as the locking element is preferred. In particular, the locking element preferably has a partially circular cylindrical shape. The central axis of the locking element is preferably oriented orthogonally to the coupling direction.

[0026] Designing the locking element as a roller facilitates its repositioning via the eccentric section or the intermediate link. It also simplifies the installation of the locking element in the receiving space.

[0027] An end face of the intermediate member facing the locking body is preferably offset from the central axis of the locking body, so that when the intermediate member is moved by means of the control shaft of the locking body, it is pressed in the direction of the locking recess of the top jaw.

[0028] Preferably, the eccentric section or the intermediate element are not the only elements that exert force on the locking body. A design with at least one spring assembly is preferred, by means of which the locking body is pressed towards the locking position. The spring force of this assembly ensures that the top jaw is held in position even after the locking mechanism is released via the control shaft. The top jaw can nevertheless be removed manually or automatically against the spring force.

[0029] Preferably, the clamping jaw is designed such that an upper jaw can be placed on the base jaw in two different orientations. Depending on the orientation of the upper jaw, the clamping system can be used as an internal or external clamping device. It is possible to use the same upper jaw in different orientations on the base jaw.

[0030] To enable the placement and locking of top jaws in two different orientations, some of the components of the base jaw are preferably provided in duplicate. In particular, the base jaw preferably has two locking elements, each arranged in a receiving space and movable for the purpose of locking. Preferably, the two locking elements are movable by means of a common control shaft. In particular, a rotational movement of the control shaft causes the locking elements to be moved in opposite directions.

[0031] The base jaw preferably has two receiving slots on its upper side for the coupling extension of the top jaw. These receiving slots preferably define coupling directions that differ from each other. The two locking elements mentioned are each arranged in receiving chambers adjacent to the receiving slots.

[0032] In addition to the clamping jaw itself, the invention also relates to a clamping jaw system for clamping workpieces. This clamping jaw system has a chuck body against which a plurality of clamping jaws of the described type can be positioned. In particular, preferably, there are at least two, three, or four such clamping jaws that are radially displaceable relative to a main axis of the chuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Further advantages and aspects of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are explained below with reference to the figures. Fig. Figure 1 shows a clamping jaw system according to the invention in a frontal view. Fig. Figure 2 shows a clamping jaw of the clamping jaw system of the Fig. 1 in perspective view. The Fig. 3A and Fig. 3B shows the clamping jaw according to Fig. 2 in side views in two different configurations, namely as an internal clamping jaw and as an external clamping jaw. Fig. 4A and Fig. Figure 4B shows a basic jaw of the clamping jaw in two different perspective views. Fig. Figure 5 shows the underside of an attachment jaw. Fig. Figure 6 shows the base jaw in a cutaway view. Fig. Figure 7 shows a control shaft of the base jaw in a separate illustration. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0034] Fig. Figure 1 shows a clamping jaw system 100 comprising a chuck body 110 and three clamping jaws 10 radially aligned to a central axis of the clamping jaw system 100, of which in Fig. 1 only the respective base jaw 20 is visible. The clamping jaw system 100 can be part of a lathe and serves the purpose of clamping workpieces for rotary machining.

[0035] The clamping jaws 10 of the clamping jaw system 100 are designed as compound clamping jaws 10 with a base jaw 20 and a top jaw 70.

[0036] In Fig. Figure 2 shows a clamping jaw 10 in its entirety. The clamping jaw 10 consists of the previously mentioned components of the base jaw 20 and the top jaw 70. The base jaw 20 is attached to the chuck body 110 so that its underside can slide. A coupling and locking mechanism is provided on the upper surface 26 of the base jaw 20 and the lower surface 76 of the top jaw 70; this mechanism will be explained in more detail below.

[0037] The top jaw 70 is attached to the base jaw 20 by means of the aforementioned coupling and locking mechanism. The top jaw 70 provides the actual clamping surface 72, whereby this clamping surface 72 can be directed radially outwards or radially inwards, depending on the type of top jaw and its orientation when attached to the base jaw 20. In the case of the Fig. 2 the clamping surface 72 is directed radially outwards.

[0038] The Fig. 3A and Fig. Figure 3B illustrates the coupling and locking mechanism and its use for locking the top jaw in its function as an external clamping jaw ( Fig. 3A) and as an internal clamping jaw ( Fig. 3B).

[0039] The main contact surfaces 30, 80 of the base jaw 20 and the top jaw 70 are provided on their upper surface 26 and lower surface 76, respectively. As can also be seen from the Fig. 3A and Fig. As can be seen in 3B, the base jaw 20 and the top jaw 70 lie flat against each other here.

[0040] The contact surface 30 of the base jaw 20 has two receiving slots 32, which extend to the side surfaces 28 of the base jaw 20 and are thus also accessible from the side. Corresponding to these receiving slots 32, the top jaw 70 has a coupling extension 82 on its underside, which extends into the receiving slot 32 when the top jaw 70 is mounted.

[0041] The two receiving slots 32 serve to receive the coupling extension 82, depending on the orientation in which the top jaw 70 is attached. The top jaw 70 can be designed such that it can be coupled to the base jaw 20 in both orientations without further modifications. Alternatively, different top jaws can be provided, each of which can only be coupled in one orientation.

[0042] If the top jaw 70 of the exemplary embodiment serves to clamp the workpiece from the outside, it is positioned accordingly. Fig. 3A is attached. The coupling extension 82 is received in the left-hand receiving shaft 32 of the base jaw 20, which is located inside the clamping system. If the top jaw 70 is used to clamp the workpiece from the inside, it is attached accordingly. Fig. 3B attached. The coupling extension 82 is then received in the right-hand and, with respect to the clamping system, outer receiving shaft 32 of the base jaw 20.

[0043] As shown by the Fig. 3A and Fig. As can be seen in Figure 3B, the receiving shafts 32 and the coupling extension 82 are not aligned orthogonally to the feed direction 2, but are slightly angled towards it. The respective coupling / uncoupling direction 4 forms an angle of approximately 70° with the feed direction.

[0044] This inclination results in the workpiece being arranged on the inside of the clamping jaw 10 in the case of Fig. 3A and the workpiece arranged on the outside of the clamping jaw 10 in the case of the Fig. The force 8 acting on the top jaw 70 via the clamping surface 72 presses the coupling extension 82 against an inclined contact surface 33 of the receiving shaft 32, thus pressing the top jaw 70 into its intended position, in which the contact surfaces 30, 80 of the base jaw 20 and the top jaw 70 lie flat against each other.

[0045] Furthermore, in the Fig. 3A and Fig. Figure 3B shows that each of the two receiving shafts 32 is connected to a receiving chamber 36 for receiving a cylindrical locking element 40. The receiving shafts 32 and the receiving chambers 36 are connected to each other, with a connecting gap having a clear width that is smaller than the diameter of the locking elements 40. The locking elements 40 can therefore project into the receiving shaft 32, but cannot completely extend into the receiving shaft 32.

[0046] Both locking elements 40 are spring-loaded. For this purpose, spring devices 38, for example with a coil spring, are received in bores that open into the receiving chambers 36. The locking elements 40 are thereby pressed into their end position facing the respective receiving shaft 32, in which they partially protrude into the receiving shaft 32.

[0047] The coupling extension 82 of the top jaw 70 has a recess on its side facing the receiving space 36, which extends transversely to the coupling direction 4 and forms a locking recess 86. When the locking element 40 is in the aforementioned end position, it projects into this locking recess 86. However, if the locking mechanism described below has not been engaged, the top jaw 70 can still be removed, whereby the locking element 40 is indirectly deflected against the force of the spring assembly 38.

[0048] For the purpose of securing the respective locking element 40 in the locking position, which is prevented by the removal of the top jaw 70, the base jaw 20 has a control shaft 60 which, in the present embodiment, extends parallel to the feed direction 2 through the body of the base jaw 20. The control shaft 60 is accessible from the outside of the clamping jaw 10 and has an actuating structure 64, in this case in the form of a hexagon, as shown in Fig. 4A can be seen. A retaining plate is provided at the opposite inner end of the clamping jaw 10 to secure the control shaft 60 in the body of the base jaw 20.

[0049] The Fig. 6 and Fig. Figure 7 illustrates the structure of the control shaft 60 and its function. As in Fig. As can be seen in Figure 7, the control shaft 60 has two eccentric areas 62, in the area of ​​which the outer surface of the control shaft 60 is not equidistant to the axis of rotation 6 of the control shaft, but forms an annular surface arranged eccentrically to it.

[0050] As shown by the Fig. As can be seen in Figure 6, the two eccentric sections 62 are each arranged in the area of ​​openings 67 that connect the area of ​​the control shaft 60 with the receiving spaces 36 for the locking elements 40. Within these openings 67, an intermediate element 66 is arranged, the end of which facing the locking element 40 is provided with an inclined end face.

[0051] When the control shaft 60 is rotated via the actuating structure 64, the eccentric design in the eccentric areas 62 causes the intermediate elements 66 to move in the openings 67 relative to Fig.6 are pressed upwards and thus further into the receiving spaces 36. Due to the inclined end faces of the intermediate members 66, this causes the locking elements to be shifted towards the receiving shaft or secured in this position. The locking element 40, which is engaged in the locking recess 86 of the coupling extension 82 of the top jaw 70, prevents the top jaw 70 from being removed. Applying force to the top jaw 70 in the decoupling direction does not cause separation, as the intermediate member 66 cannot move due to the rotational position of the control shaft 60.

[0052] If the top jaw 70 is to be replaced, the control shaft 60 is rotated via the actuating structure 64, in this case by approximately 135°. The intermediate elements 66 can then partially slide out of the receiving spaces 36 again, thus allowing the locking element 40 to be moved towards its release position and thus separating the top jaw 70 from the base jaw 20. After fitting a different top jaw 70 or changing the orientation of the top jaw 70, the locked position is restored by rotating the control shaft 60 again.

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