WO2009087074A1

WO2009087074A1 - Clamping element

Info

Publication number: WO2009087074A1
Application number: PCT/EP2009/000008
Authority: WO
Inventors: Matthias Fischer
Original assignee: Vel Vega - Design E Tecnologia Ind. Unip. Lda.
Priority date: 2008-01-04
Filing date: 2009-01-03
Publication date: 2009-07-16
Also published as: EP2234762A1; CN101959649B; DE102008004287A1; CN101959649A; EP2234762B1

Abstract

The invention relates to a clamping element for fixing a workpiece, comprising a housing (10) that is fixed during operation, a clamping lever (60) that can be moved relative to the housing (10) and has a clamping region (64) for subjecting the workpiece to a force as well as a piston (70) that can be deployed in a translatory manner relative to the housing (10) in a deployment direction (4). The invention is characterized in that the piston (70) is designed for pivoting the clamping lever (60) so that the clamping lever (60) can be moved between a released initial state (60) and a clamped final state. According to the invention, the clamping lever (60) is mounted to the housing (10) or the piston by at least one eccentric disk (80a, 80b). The clamping element according to the invention allows for a compact and stable design.

Description

clamping element

description

Field of application and state of the art

The invention relates to a clamping element for fixing a workpiece with a fixed housing in operation, a relative to the housing movable clamping lever with a clamping range for applying force to the workpiece and a relative to the housing in a direction of extension extendable piston, wherein the piston is designed for pivoting the clamping lever in that the tensioning lever is movable between a released initial state and a tensioned final state.

Generic clamping elements are known from the prior art. They serve to clamp a workpiece on a clamping surface. For direct contact with the workpiece, the clamping lever is provided, which is movable relative to the housing and which can be pivoted by an extension of the piston such that the clamping area comes to rest on the workpiece and this presses with a clamping force against the clamping surface.

Since the clamping lever is formed in generic clamping elements for carrying out a pivoting movement and thus describes a circular path relative to a pivot axis provided therefor and since the piston is designed to describe a translational movement, the clamping lever can not be mounted on the housing and the piston simultaneously pivotable. As a balancing mechanism is known for overcoming this problem from the prior art, for example, between the housing and the clamping lever to provide a pair of tabs, the tabs of this pair of tabs on the one hand on the clamping lever and on the other hand are pivotally mounted on the housing.

However, such clamping elements with a pair of tabs have an unsatisfactory stability, in particular against lateral forces, ie forces in the direction of the pivot axes of the tabs on. In addition, the use of such swivel tabs leads to a variety of vulnerabilities to the respective pivot axes, since chips can get between the components of the clamping element and prevent satisfactory functioning. Other disadvantages of such clamping elements with a pair of tabs are the presence of many interfering edges and the associated risk of accidents and in the relatively large size of such clamping elements.

Task and solution

The object of the invention is to develop a generic clamping element to the effect that the disadvantages of the prior art can be avoided or reduced.

According to the invention this is achieved in that the clamping lever is mounted on the housing or on the piston by means of at least one eccentric disc.

As an eccentric disc in the context of the invention, a rotatably mounted about its central axis disc is considered. The eccentric disc is preferably mounted on its lateral surface by being inserted into a corresponding circular recess of the clamping lever, the piston or the housing. From this eccentric disc is an eccentric shaft extending, which extends parallel to the central axis of the eccentric disc and whose center line from the central axis of Exzen- terscheibe is spaced. This eccentric shaft is mounted on another than the component on which the eccentric disc is mounted.

As far as the respective eccentric disc is concerned and the component bearing the eccentric shaft is concerned, a large number of combinations is possible. In an embodiment in which the eccentric disc is provided for connecting the clamping lever to the housing, the eccentric disc may be mounted on the clamping lever or on the housing, wherein the eccentric shaft is mounted on the respective other component. In these embodiments, the piston and the clamping lever are preferably juxtaposed directly by means of a relative to the clamping lever and relative to the piston stationary pivot axis.

As an alternative to the design in which the eccentric disc is provided for connecting the clamping lever to the housing, the eccentric disc can also be used for connecting the clamping lever to the piston. Again, it is possible to rotatably support the eccentric disc on the piston or on the clamping lever, while the eccentric shaft is also mounted here on the respective other component. In this design, in which the eccentric disc is provided between the piston and the tensioning lever, the tensioning lever is preferably mounted pivotably directly on the housing, wherein the relevant pivoting axis is stationary both to the tensioning lever and to the housing.

The eccentric shaft can be designed to be rotatable relative to the eccentric disk and relative to the component in which it is mounted, that is to say the housing, the piston or the tensioning lever. However, it can also be provided rotatably on the eccentric disc or on the component in which it is mounted.

With regard to the intended relative mobility of the interconnected by the eccentric disc components corresponds to Eccentric solution known from the prior art solution with a pair of tabs, the pivot axes of the tab pair find their correspondence in the center axes of the eccentric and the eccentric shaft.

The eccentric disc, together with the eccentric shaft fulfills the task of a compensating means. The use of an eccentric disc with an eccentric shaft as a compensation means to allow the pivoting movement of the clamping lever relative to the housing on the one hand and against the piston on the other hand, offers over the known from the prior art connecting straps considerable advantages. Thus, by such a connection in particular the number of critical areas, can penetrate into the chips and can interfere with the functioning of the clamping element, can be significantly reduced. This is achievable in particular in that the eccentric disc is mounted in a receiving bore. This design causes a rotation of the eccentric disk about its central axis up to the resulting change in position of the eccentric shaft has no effect on the outer shape of the eccentric disk and the eccentric disk bearing component. This leads to a low risk of accidents and high reliability. Furthermore, such an embodiment with an eccentric, in particular with regard to the absorption of lateral forces against a solution with tabs considerably advantageous. The transferable from the clamping lever to the housing forces in the context of the clamping state are higher. Another advantage is that due to the eccentric disks and the arrangement of the eccentric shafts on the eccentric disks, the distance between the pivot axes of the compensating means, in the case of the eccentric disk solution, the spacing of the center axis of the eccentric disk relative to the center axis of the eccentric shaft, can be determined considerably more flexibly and especially small can be chosen. This makes it possible to adjust these pivot axes exactly as far as space each other that the eccentric can fulfill its task as a balancing agent. The small spacing of the pivot axes is particularly advantageous for a compact construction of the clamping element. By a small spacing of the center axes of the eccentric shaft and the eccentric disc can be further achieved that in the course of relaxing the clamping element of the clamping lever is lowered and is retracted transversely to the extension direction of the piston, which serves the compact structure of the clamping element.

In a preferred embodiment of the invention, the clamping element has a clevis connection between the clamping lever on the one hand and the housing or the piston on the other hand, wherein the clevis connection a clevis with two Gabelkopffortsätzen, which is fixedly connected to the clamping lever or to the housing or the piston, and a counter portion which is fixedly connected to the housing or the piston or the clamping lever. The clevis connection is provided between the two components, which are mutually movable by means of the eccentric disc. The clevis connection ensures a high degree of stability and optimum power transmission. Both the fork head and the counter section extending between the fork head extensions of the clevis can be associated with each of the components which are movable relative to one another according to the invention, that is to say the tension lever, the piston and the housing, and firmly connected thereto.

However, as regards the connection of the housing to the clamping lever by means of the eccentric disk, it is considered to be particularly advantageous that the fork head is fixedly connected to the housing and the counterpart section is formed by the clamping lever. The Gabelkopffortsätze are preferably integrally formed on the housing. By such a design, a particularly high stability is achieved. The forces resulting from the tensioning lever as a result of the tensioning process can NEN via the eccentric shaft and the at least one eccentric disc are discharged directly into the one-piece housing. Furthermore, the fork head, which laterally surrounds the clamping lever, is particularly well suited for receiving sensors which can monitor the position of the clamping lever and the reaching of the clamping state. With regard to a connection of the clamping lever with the piston by means of the eccentric disc, it is considered to be particularly advantageous if the clevis is fixedly provided on the clamping lever and the counter portion is formed by the piston. The width of the mating section in the direction of the center axes of the eccentric disc and the eccentric shaft is preferably adapted to a space provided between the Gabelkopffortsätzen such that there is minimal play, preferably a clearance of less than 1 mm. This avoids that chips can penetrate between clamping lever and piston or housing.

In a further development of the invention, the at least one eccentric disc is rotatably mounted on the counter portion, wherein the eccentric eccentric connected to the eccentric eccentric shaft is mounted on the Gabelkopffort- sets. In this design, only a central eccentric is required, which is arranged between the Gabelkopffortätzen. The eccentrically provided on the eccentric eccentric shaft extends outwardly into the region of Gabelkopffortsätze and is there rotatably or rotatably mounted.

It is considered particularly advantageous in this design with an eccentric disk provided on the countersection, when the eccentric disk is completely covered by the fork head extensions. This reduces the risk that chips get between the eccentric disc and the inner wall of the receiving bore, in which the eccentric disc is mounted. As complete coverage, it is considered to be in a perspective in the direction of the central axis the eccentric disc of the gap between the eccentric disc and the eccentric disc receiving bore is hidden under all intended operating conditions by the Gabelkopffortsätze.

In an alternative embodiment for supporting the eccentric disc on the mating section, an eccentric disk is rotatably mounted on both fork head extensions, the eccentric shaft connected eccentrically to the eccentric disk being mounted on the mating section. By virtue of this configuration, the counterpart section can be designed to be particularly small compared with the eccentric disk, due to the preferably smaller diameter of the eccentric shaft. The two eccentric discs are rotatably mounted on the Gabelkopffortsätzen and always move together with the intended use together with the Gabelkopffortätzen. The receiving holes in which the eccentric discs are included, need not be through holes, but can be designed as facing each other open blind holes. However, it is preferred that the holes are formed as through holes.

In a particularly advantageous development, the at least one eccentric disk in the axial direction has a tapered shape. This tapered shape has the corresponding advantage in design of the receiving bore of the eccentric disc that the eccentric disc can be inserted only in one direction in the receiving bore and removed only in the opposite direction from the bore. This makes it possible, in particular, to insert the eccentric discs into the corresponding bores, in each case from the side of the counterpart portion, and to prevent the eccentric discs from slipping out of their associated bores by subsequent insertion of the counterpart portion. The tapered shape of the eccentric discs can be achieved for example by a conical design and corresponding conical holes. As preferred, however, a design is considered in which a first portion of the eccentric disc, which is arranged in operation in the respective corresponding bores, is cylindrical, but with this first section is followed by a preferably circumferential and radially outwardly facing retaining collar, the at least in sections has a relative to the central axis of the eccentric larger radius than the associated receiving bore.

In a further development of the invention, the housing has an approximately cylindrical fixing portion, on whose outer side an external thread is provided and by means of which the housing in its entirety in a corresponding bore of a clamping device can be screwed. The fixing portion, which is an integral part of the housing and is fixedly connected to this, serves itself to determine the housing. For this purpose, a corresponding recess with an internal thread is provided on a clamping surface on which the workpiece is to be clamped, into which the clamping element can be screwed in its entirety. In particular, it is advantageous that the relative position of the clamping element relative to a clamping surface is flexibly adjustable by the depth of engagement, whereby an applicability for workpieces of different heights is achieved. Thus, in particularly large workpieces, the clamping element can be screwed into the clamping device only a few turns deep, while in other smaller workpieces the fixing section is screwed approximately completely into the clamping device. Preferably, a locking means, in particular a lock nut is additionally provided on the outside of the fixing section. Media supply lines for supplying a pressure medium such as air or oil may be provided on the underside of the housing, in particular on the underside of the fixing portion. However, a configuration is considered particularly advantageous in which corresponding connections are provided on the lateral surface of the cylindrical fixing section. It is particularly advantageous that at least two inlet openings for supplying the pressure medium are provided on the outside of the cylindrical fixing portion, wherein the inlet openings are spaced apart in the direction of a cylinder axis of the fixing portion. These two inlet openings can be used alternatively. Depending on which of the inlet openings is to be used, the other or the other inlet openings are preferably closed by means of plugs. The design with a plurality of inlet openings makes it possible, irrespective of the depth of engagement of the fixing section, to have at least one inlet opening at which supply of the pressure medium can take place.

According to different embodiments, clamping elements according to the invention can be designed relative to one another and relative to a clamping surface with respect to the arrangement of the clamping lever, the piston and the housing. Preferred embodiments comprise an embodiment as a vertical clamping element, in which the force vector of the force acting on the workpiece from the clamping region of the clamping lever in the final state runs approximately parallel (+/- 15 °) to the extension direction of the piston and to a surface normal on the clamping surface. They further include a configuration as a horizontal clamping element, in which the piston is aligned approximately parallel (+/- 30 °) to the clamping surface. A special form of these horizontal clamping elements form the pull-down clamping elements, in which the force vector of the force acting on the workpiece from the clamping region of the clamping lever with the clamping surface at an angle of about 30 ° (+/- 10 °). Brief description of the drawings

Further advantages and features of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are illustrated in the figures. Showing:

1 a, 1 b show a first embodiment of a tensioning element according to the invention in an unstressed and a tensioned state, in each case in a perspective and a sectional view,

FIG. 2 shows the individual parts of the tensioning element of FIGS. 1a and 1b,

FIG. 3 shows a second embodiment of a device according to the invention

Clamping element,

FIG. 4 shows the individual parts of the second embodiment of a tensioning element according to the invention of FIG. 3,

Figure 5 shows a third embodiment of an inventive

Clamping element,

Figure 6 shows the items of the embodiment of Figure 5 and

Figure 7a, 7b, the embodiment of Figures 5 and 6 in an untensioned and a tensioned state.

Detailed description of the embodiments Figures 1a, 1b and 2 show a first embodiment of a tensioning element according to the invention and its individual parts.

Referring to Figure 2 and Figure 1 a, the individual parts of the embodiment of Figures 1a, 1 b and 2 and the connection of these items are first explained.

The clamping element has a housing 10, which has a U-shaped clevis portion 20 and an adjoining cylindrical fixing portion 40. The clevis portion 20 has two planar Gabelkopffortsätze 22a, 22b, which are arranged parallel to each other and define an intermediate space 24 laterally. The Gabelkopffortsätze 22 a, 22 b are integrally formed at its lower end to a base plate 26. From this base plate 26, the cylindrical fixing portion 40 extends downward. 1a, a cylinder bore 42 is provided in this fixing section, which serves to receive a piston 70, which will be described further below. A through hole 44 connects coaxially to the cylinder bore 42 and extends through the base plate 26 into the clearance 24 between the fork head extensions 22a, 22b. On the outside of the fixing portion 40, an external thread 48 is provided, by means of which the clamping element can be screwed in a variable depth in a corresponding bore of a clamping surface. On this external thread a lock ring 49 is screwed with internal thread, which can be countered by screwing the clamping element in this bore of the clamping surface against the clamping surface. In the fork head extensions each receiving holes 30a, 30b are mutually aligned, which serve to receive the eccentric discs 80a, 80b described below. In addition to the housing 10, the clamping lever 60 forms the second main component of the clamping element. The tension lever 60 has a width that is only slightly smaller than the width of the clearance 24 between the fork head tongues 22a, 22b.

The clamping lever 60 has a front portion 62, on the underside of a clamping portion 64 is provided. The clamping area is formed as a spherical surface, which is provided for line contact with the workpiece to be clamped.

In a rear portion 66 of the clamping lever 60 is formed as a clevis and has a cross-section with an approximately U-shaped configuration. In this rear portion 66 front and rear holes 68 a, 68 b are provided in the clamping lever 60. By means of the rear holes 68b provided in the region of the fork head section 66, the clamping lever 60 in the assembled state of FIGS. 1a and 1b encompasses a head section 72 which is provided at the upper end of the piston 70. By means of a bolt 74, which extends in the assembled state of the clamping element through the bores 68b and through the provided in the head portion 72 of the piston 70 bore 73, the piston 70 and the tension lifting 60 are directly against each other. As can be seen from FIG. 1a, in the assembled state, the piston is inserted from below into the cylinder bore 42, so that the head section 72 is arranged through the through-bore 44 in the free area 24 between the fork head extensions 22a, 22b. In addition to the connection of the clamping lever 60 to the housing 10 via the lever 70, the clamping lever 60 is also connected to the housing by means of the two eccentric discs 80a, 80b. The eccentric discs 80a, 80b are arranged in the assembled state in the receiving bores 30a, 30b. They are inserted for this purpose from the free area 24 into the receiving bores 30a, 30b. So the eccentric discs 80a, 80b do not slip outwardly out of the receiving bores 30a, 30b, they have a circumferential retaining collar 82a, 82b at their end facing the free area 24. While the diameter of the eccentric discs 80a, 80b is matched to the bores 30a, 30b away from the retaining collar 82a, 82b such that a tight clearance fit is produced, the diameter of the eccentric discs 80a, 80b is greater than the diameter of the retaining collar 82a, 82b Receiving bores 30a, 30b. This prevents the eccentric discs from slipping outwardly out of the receiving bores 30a, 30b.

In the eccentric discs 80a, 80b each eccentrically arranged and parallel to the central axis of the eccentric discs 80a, 80b aligned bore 84a, 84b is provided. To connect the clamping lever 60 to the housing 10, a bolt 88 passes through these eccentric bores 84 and the bore 68a of the clamping lever 60. The bolt 88 forms the eccentric shaft 88 of the eccentric discs 80a, 80b.

In the tensioned state, which is shown in Figure 1 b, a clamping lever 60 upwardly closing surface 60a is aligned with the end faces 23a, 23b of the Gabelkopffortsätze 22a, 22b, so that a nearly uniform surface is formed. This, as well as the small clearance between housing and clamping lever cause chips can hardly get into critical areas of the clamping element. The risk of damaging the workpiece when placing a workpiece on a clamping surface by accidental contact with the clamping element, is low.

The eccentric has the intended function, the tensioning lever 60 during the tensioning operation, ie during the transition from the state of Figure 1a to the state of Figure 1 b, to guide such that the bore 68b and thus the pivot axis between the piston 70th and the tensioning lever 60 is moved parallel to the extension direction 104 of the piston 70. Due to the design of the eccentric discs 80a, 80b, the eccentricity between the axis of rotation 6 of the eccentric discs 80a, 80b and defined by the center axis 8 of the eccentric shaft 88 pivot axis 8 of the clamping lever 60 relative to the eccentric discs 80a, 80b are set freely. The pivotal movement of the clamping lever 60 thus deviates only slightly with the appropriate design in the kinematic mandatory dimensions of a pivoting movement about a housing-fixed pivot axis. As the side views of Fig. 1a and 1b clearly show, is achieved by the design of the clamping element with eccentric 80a, 80b and the small spacing of the axes 6, 8 beyond that the clamping lever 60 by the relative displacement of the axes 6, 8 to each other in the untensioned state of Fig. 1a is withdrawn in its entirety to the left and lowered down. The clamping element is thus hardly larger in the untensioned state than in the tensioned state. In particular, in both operating states, the tension lever 60 is almost completely covered by the protective fork head extensions 22a, 22b, so that the risk of accidents is reduced.

FIGS. 3 and 4 show a second embodiment of a tensioning element according to the invention. With respect to the kinematic coupling of the pivot lever 160 provided in the second embodiment with respect to the housing 110, the difference from the embodiment of Figures 1 and 2 is that in this embodiment, the eccentric disc 180 is not stored in the Gabelkopffortsätzen 122a, 122b, but in the pivot lever 160 itself This has for this purpose a trained as a through hole receiving bore 161, into which the eccentric disc 180, which corresponds to the width of the pivot lever 160, is used. The eccentric shaft 188, which in turn eccentrically in a bore 184 of the eccentric disc 180 is mounted, extends on both sides in bearing bores 128a, 128b of the Gabelkopffortsätze 122a, 122b.

The kinematic effect of the eccentric disc 180 corresponds to that of the eccentric discs 80a, 80b of the embodiment of FIGS. 1 and 2. Differences arise in terms of the design of the components. In particular, the clamping lever must be designed to accommodate the eccentric larger. However, only one eccentric is required.

A third embodiment is shown in FIGS. 5 to 7. The figures 5 and 6 show the clamping element in a perspective view in the assembled state and in the disassembled state.

The main differences between this embodiment and the previous embodiments is that it is a horizontal clamping element in the embodiment of Figures 5 to 7. As a result, the piston 270 in the clamping element is not vertical, but arranged almost horizontally and parallel to a base 210 a of the housing 210. In this case, the tensioning lever 260 is shaped in such a way that an approximately vertically oriented introduction of force into a workpiece can nevertheless take place via the tensioning region 264.

In addition to the opposite to the embodiment of Figures 1 to 4 deviating alignment of the clamping element is a further significant difference that the clamping lever is mounted directly on the housing 210 in this embodiment by means of a bolt 288. The pivot axis defined by the bolt 288 and the holes 228a, 228b, 268a penetrated by it is stationary relative to the housing 210 and relative to the tensioning lever 260. The eccentric discs are provided instead of the pivotal coupling of clamping lever 260 and housing 210 for the pivotal coupling of clamping lever 260 and piston 270. For this purpose, the two eccentric disks 280a, 280b, which correspond in their design to the eccentric disks of FIGS. 1 and 2, are rotatably provided in receiving bores 269a, 269b of the clamping lever 260 formed in sections as a clevis. The connection with the head portion 272 of the piston 270 and a bore 273 provided therein by means of an inserted eccentric shaft 274 which extends through eccentric bores 284 a, 284 b of the eccentric discs 280 a, 280 b and through the bore 274 of the piston 270.

The tensioning operation that can be performed with this tensioning element, which is shown in FIGS. 5 and 6, is shown in FIGS. 7a and 7b.

Claims

claims

A clamping element for fixing a workpiece to an operationally fixed housing (10, 110, 210), a clamping lever (60, 160, 260) movable relative to the housing (10, 110, 210), having a clamping region (64, 164, 264) ) for applying force to the workpiece and a piston (70; 170; 270) which can be extended in a translatory manner relative to the housing (10; 110; 210), the piston (70; 170; 270) being used to pivot the clamping lever (60 160; 260) such that the tensioning lever (60; 160; 260) is movable between a released initial state and a tensioned end state, characterized in that the tensioning lever (60; 160; 260) is fixed to the housing (10; 110) or on

Piston (270) by means of at least one eccentric disc (80a, 80b;

180; 280a, 280b) is stored.

2. Clamping element according to claim 1, characterized by a clevis connection between the clamping lever (60; 160; 260) on the one hand and the housing (10; 110; 210) and the piston (70; 170; 270) on the other hand, wherein the clevis connection a clevis (20) having two fork head extensions (22a, 22b; 122a, 122b) fixedly connected to the tension lever (260) or to the housing (10; 110) and the piston, respectively, and a mating portion (60; 160; 270) which is fixedly connected to the housing or the piston (270) or the clamping lever (60; 160).

3. clamping element according to claim 2, characterized in that the at least one eccentric disc (180) is rotatably mounted on the counterpart portion (160), wherein an eccentrically connected to the eccentric eccentric shaft (188) is provided, which is mounted on the Gabelkopffortätzen (122a, 122b).

4. Clamping element according to claim 3, characterized in that the at least one eccentric disc (180) is completely covered by the fork head extensions (122a, 122b).

5. Clamping element according to claim 2, characterized in that in each case an eccentric disc (80a, 80b, 28Oa ₁ 280b) is rotatably mounted on both Gabelkopffortsätzen (22a, 22b), wherein an eccentrically with the eccentric disc (80a, 80b, 280a, 280b) connected eccentric shaft (88; 274) which is mounted on the counter portion (60; 270).

6. Clamping element according to one of the preceding claims, characterized in that the at least one eccentric disc (80a, 80b, 280a, 280b) has a tapered shape in the axial direction.

7. Clamping element according to one of claims 2 to 6, characterized in that the fork head (20) on the housing (10; 1 10; 210) is provided, wherein the fork head extensions (22a, 22b; 122a, 122b) preferably in one piece on the housing ( 10, 110, 210) are formed.

8. Clamping element according to one of the preceding claims, characterized in that the housing (10) has an approximately cylindrical fixing portion (40) on whose outer side an external thread (48) is provided and by means of which the housing (10) can be screwed in its entirety into a corresponding bore of a clamping device.

9. Clamping element according to claim 8, characterized in that on the outside of the cylindrical fixing portion (40) at least two inlet openings for supplying a pressure medium are provided, wherein the inlet openings in the direction of a cylinder axis of the fixing portion (40) are spaced from each other.