DE202014103558U1 - jig - Google Patents

Abstract

Clamping device (10) for internal clamping of a test object (11), with a clamping unit (10) which is arranged coaxially to a longitudinal axis (L) and which has several clamping fingers (26) which can be expanded radially outward from the longitudinal axis (L) by means of an expansion body (31) each having a clamping surface (30) oriented radially outward from the longitudinal axis (L) and an impact surface (33) facing the longitudinal axis (L), the distance of each impact surface (33) from the longitudinal axis (L) starting from free end (27) of the clamping finger (26) decreases along the longitudinal axis (L) in a clamping direction (F), the expansion body (31) having an expansion surface (32) with which it rests on the impact surfaces (33) and wherein the Spreader body (31) is connected to an outer end of an actuating rod (37) extending along the longitudinal axis (L) into an interior (15) of a housing (12) of the clamping device (10), with an actuating rod (15) in the interior (15) of the housing (12) arranged and movably mounted along the longitudinal axis (L) first coupling body (40), to which the actuating rod (37) is connected, with one arranged in the interior (15) of the housing (12) and relative to the longitudinal axis (L) to the first coupling body (40) movably mounted second coupling body (56), with a force generating unit (57) that connects the two coupling bodies (40, 56), and with an operating device (80) by means of which the second coupling body (56) in the clamping direction (F) can be moved parallel to the longitudinal axis (L) for internal clamping of the test object (11).

Description

The invention relates to a clamping device for internal clamping of a specimen. With inner spans is meant that the clamping device engages with a clamping unit at least partially in a recess or a cavity of the test specimen and presses against a wall enclosing the recess of the test piece inside to hold the specimen. For this purpose, the clamping device on a clamping unit which is arranged coaxially to a longitudinal axis. To the clamping unit includes a plurality and, for example, three clamping fingers, which are arranged distributed in a circumferential direction about the longitudinal axis. Each clamping finger has a radially arranged with respect to the longitudinal axis outside, facing away from the longitudinal axis clamping surface. With the aid of an expansion body, which is arranged between the clamping fingers, they can be moved radially away from the longitudinal axis and / or bent and / or deformed in order to effect internal clamping of the test object.

Such a clamping device is made, for example DE 18 12 525 A known. The clamping fingers have an expander facing the loading surface. The distance of the loading surfaces decreases from the free end of the clamping fingers along a longitudinal axis. About a clamping screw, a spherical expansion body between the clamping fingers is arranged. By tightening the clamping screw, the clamping fingers are moved outwards or bent away from the longitudinal axis in order to clamp a test object. Instead of the clamping screw, the movement of the spherical expansion body along the longitudinal axis can also take place via a tailstock. In both cases, the spherical expansion body must be accessible in the region of the free ends of the clamping fingers in order to rotate the clamping screw or to allow the engagement of a tailstock to the spreader.

Another jig is in DE 41 13 449 C1 described. There, a specimen is clamped from the inside by clamping balls are pressed radially from a longitudinal axis away from the inside against the DUT. For this purpose, the clamping device has conical to the longitudinal axis extending expansion surfaces on which the clamping balls are supported. By axial displacement of the clamping balls on the expansion surfaces, the balls for clamping can be moved radially away from the longitudinal axis in order to press against the test specimen and to tension it.

Based on the prior art, it can be regarded as an object of the present invention to provide an easy-to-handle clamping device which is set up for internal clamping of a test object.

This object is achieved by a clamping device with the features of claim 1.

The clamping device has a clamping unit arranged coaxially to a longitudinal axis with a plurality of clamping fingers. For example, three or more clamping fingers may be arranged distributed in the circumferential direction about the longitudinal axis. The clamping fingers are separated at least in the clamping area by gaps or slots. They each have a clamping surface pointing radially outward away from the longitudinal axis, and a loading surface facing the longitudinal axis. Each loading surface of a clamping finger extends inclined to the longitudinal axis such that the distance to the longitudinal axis of the free end of the clamping fingers decreases away. In particular, the loading surfaces of the clamping fingers are arranged at least in the unimpacted, undeformed state of the clamping fingers on a common conical surface. Preferably, the clamping surfaces of the clamping fingers lie in not acted undeformed state of the clamping fingers on a common cylinder jacket surface.

Between the clamping fingers an expansion body is arranged, which has a spreading surface. The spreading surface abuts against the loading surfaces of the clamping fingers. In a preferred embodiment, the spreading surface is curved both in the circumferential direction about the longitudinal axis, as well as in the direction of the longitudinal axis and in particular in each case uniformly curved. The expansion body can be designed as a ball or ball segment, so that the spreading surface has the shape of a spherical surface or spherical cap.

By displacing the expansion body along the longitudinal axis in a tensioning direction, the tensioning fingers can be spread radially outward away from the longitudinal axis, wherein the tensioning fingers elastically deform and their respective clamping surface is moved away from the longitudinal axis. The movement of the expansion body in the clamping direction takes place from the free ends of the clamping fingers away along the loading surfaces. In a displacement of the expansion body along the longitudinal axis in a direction opposite to the clamping direction release direction, the clamping fingers elastically spring back into the Spannfingerausgangsstellung.

For the movement of the expansion body along the longitudinal axis is an actuating rod, at the outer end of the spreader is arranged. Starting from this outer end, the actuating rod extends along the longitudinal axis in the Inside a housing of the clamping device and is connected there to a first coupling body. The first coupling body preferably has a cylindrical contour. For connection to the actuating rod, it can have a clamping slot into which the actuating rod is inserted. With the help of a clamping screw, the actuating rod can be clamped in the clamping slot.

In addition, inside the housing, a second coupling body is movably mounted relative to the housing and relative to the first coupling body. A force generating unit is provided which connects the two coupling bodies. The force generating unit may comprise at least one spring and in particular at least one tension spring. Via an operating device, the second coupling body can be moved parallel to the longitudinal axis for clamping the clamping unit from a clamping body starting position in the clamping direction in a clamping body working position. In the clamping body working position, the second coupling body transmits a tensile force acting on the first coupling body in the tensioning direction, whereby the spreading means is pulled in the tensioning direction via the actuating rod and moved until the force acting on the expanding body is supported in the tensioning direction along the longitudinal axis. This is the case, for example, when the clamping surfaces abut the test specimen and a sufficiently large clamping force between the clamping surfaces and the test specimen is produced. The relationship between the tensile force acting on the spreader in the tensioning direction and the clamping force between the clamping surfaces and the DUT depends on the angle of inclination of the loading surfaces with respect to the longitudinal axis.

With this clamping device specimens can be clamped easily and quickly repeatable exactly. Accessibility to the clamping fingers after placing the specimen on the clamping fingers is not necessary. The clamping force exerted by the clamping fingers for clamping the test object is transmitted via the actuating rod and the coupling bodies.

If the expansion body has a spreading surface in the form of a spherical surface or spherical cap, the spreading surface between the loading surfaces of the clamping fingers is directed in a simple manner centrally and coaxially to the longitudinal axis. A uniform application of the clamping fingers is achieved. A pairing between spreader and clamping unit and grinding the spreading surface and the loading surfaces is not required in a uniformly curved in the direction of the longitudinal axis spreading surface.

It is also possible to choose the curvature of the spreading surface about the longitudinal axis and the curvature of the spreading surface in the direction of the longitudinal axis in each case constant, but different than in a ball or spherical cap of different sizes.

The tensioning device may have a limiting device in order to limit the maximum tensioning travel of the expansion body. This can be done by limiting the maximum clamping travel of the first coupling body along the longitudinal axis in the clamping direction. A further increase in the tensile force then has no effect on the spreader. The limiting device is preferably arranged on the first coupling body or cooperates with the first coupling body.

In one embodiment, the limiting device may have at least one abutment surface provided on the first coupling body and aligned obliquely and in particular at right angles to the longitudinal axis. The stop surface is associated with a counter surface on the housing. The maximum available clamping travel and the associated maximum deformation of the clamping fingers is determined by the position of the counter surface on the housing. As a result, a plastic deformation of the clamping fingers can be avoided. It is thus ensured that the clamping fingers move back into their Spannfingerausgangsstellung after loosening.

Preferably, a return device is present. The return device causes a restoring force, which counteracts the clamping direction in a release direction on the first coupling body and / or the second coupling body acts to urge the respective coupling body in a Kopplungskörperausgangslage. The restoring force is greater than zero in amount when the first coupling body and / or the second coupling body are moved out of the coupling body starting position. Preferably, the restoring force is greater than zero even in the coupling body starting position of the respective coupling body, but may alternatively be equal to zero. Preferably, the Kopplungskörperausgangslage of the first and / or second coupling body is selected so that the clamping fingers are undeformed in their Spannfingerausgangsstellung by the spreader. The maximum available over the limiting device clamping path can amount to a maximum of one millimeter and preferably at most 50 microns in one embodiment.

It is advantageous if a position adjustment device is provided which predetermines a coupling body starting position of the first coupling body and / or of the second coupling body. In one embodiment, the position adjustment device can be positioned on the housing arranged Positionseinstellkörper which represents a stop for the first coupling body and / or second coupling body. In the Kopplungskörperausgangslage the relevant coupling body is applied to the Positionseinstellkörper. If a restoring device is present, the relevant coupling body is urged by the restoring force in the coupling body starting position against the position setting body.

In a preferred embodiment, the force generating unit includes at least one tension spring. One end of the tension spring is connected to the one of the two coupling bodies, while the other end is connected via a Zugkrafteinstelleinheit with the respective other coupling body. For example, the Zugkrafteinstelleinheit be interposed between the at least one tension spring and the second coupling body. About the Zugkrafteinstelleinheit the tensile force between the two coupling bodies can be adjusted, in particular in the respective Kopplungskörperausgangslage the two coupling body.

In a preferred embodiment, the tensile force adjusting unit has a first adjusting part displaceably mounted in the direction parallel to the longitudinal axis and a second adjusting part rotatably mounted in the circumferential direction about the longitudinal axis. The two adjusting parts are preferably connected to one another via a thread. By rotation of the second adjustment member, an axial movement of the first adjustment member can be effected. The first adjustment member is connected to the at least one tension spring, so that thereby the expansion path of the tension spring and thus the tensile force is adjustable.

The tension spring may be arranged in a central recess of the second coupling body coaxial with the longitudinal axis. Preferably, the first adjusting member is secured against rotation and slidably mounted parallel to the longitudinal axis of the second coupling body. The second adjustment member may be slidably supported on the second coupling body.

It is advantageous if the operating device has a control unit, which is arranged accessible on the housing and displaceable parallel to the longitudinal axis. The control panel may be configured, for example, as a co-axial with the longitudinal axis around the housing arranged operating ring. The operating ring may be mounted parallel to the longitudinal axis and / or in the circumferential direction about the longitudinal axis slidably on the housing. Such an operating ring is easy to grip from all radial directions of an operator to clamp a test specimen with the clamping device or to solve a clamped test specimen.

In a preferred embodiment, the control unit via at least one connecting element, for example a connecting pin, at least in the tensioning direction and in the release direction parallel to the longitudinal axis with the second coupling body is coupled in motion. This movement coupling thus causes the second coupling body moves together with the control panel along the longitudinal axis either in the clamping direction or in the release direction. Preferably, the movement coupling via the at least one connecting element is exclusively translationally parallel to the longitudinal axis, ie in the tensioning and loosening direction.

The control unit may preferably be mounted rotatably about the longitudinal axis on the housing and at least in a predetermined rotation angle range. In this rotational degree of freedom, there is preferably no movement coupling between the operating part and the second coupling body. The operating part is thus rotatable in the circumferential direction about the longitudinal axis, at least in the rotation angle range relative to the second coupling body. The movement coupling translationally along the longitudinal axis and the decoupling of the movement rotationally about the longitudinal axis between the operating part and the second coupling body can be achieved, for example, that the connecting element engages in a circumferential long hole extending on the control panel in the circumferential direction about the longitudinal axis. During a rotational movement of the operating part about the longitudinal axis, no rotational movement is thereby transmitted via the connecting element to the second coupling body, while the connecting element transmits a translatory movement of the operating element to the second coupling body. In this case, the length of the circumferential elongated hole in the circumferential direction can correspond at least to the rotational angle range in order to ensure the decoupling of the rotational movement between the operating part and the second coupling body. The rotation angle range of the operating part is in particular less than 90 ° and preferably less than 45 ° and more preferably less than 30 °.

The tensioning device may also have a holding device. The holding device serves to hold the operating part in a position or position when the coupling body is in its in the tensioning direction moved out of the starting position Kopplungskörperarbeitslage in which on the clamping unit or the clamping fingers a clamping force can be generated on a specimen. For this purpose, the holding device may have at least one holding part present on the operating part and in each case a cooperating, on the housing existing counter-holding part. In a holding position, the holding part and the associated counter-holding part cooperate in such a way that a movement of the second coupling body in the release direction of the Working position out toward the starting position is prevented. As a holding part, for example, serve a retaining projection which engages in a groove. At least a portion of the groove extends circumferentially about the longitudinal axis, wherein the retaining projection is in the holding position in the circumferentially extending portion of the groove. In this holding position of the holding device, an axial movement of the operating part relative to the housing and thus also of the second coupling body is prevented relative to the housing.

It is understood that, conversely, the groove on the control panel and the retaining projection on the housing may be present.

The holding device can be brought into a neutral position in which a translational movement of the second coupling body along the longitudinal axis is permitted. For this purpose, in the exemplary embodiment described above, the groove may have a section extending parallel to the longitudinal axis, so that movement of the retaining projection engaging in the groove in the release direction and in the clamping direction parallel to the longitudinal axis is possible.

Advantageous embodiments of the invention will become apparent from the dependent claims, the description and the drawings. Hereinafter, a preferred embodiment of the clamping device will be explained in detail with reference to the accompanying drawings. Show it:

1 a perspective view of an embodiment of the clamping device,

2 the clamping device off 1 in a side view,

3 the tensioning device according to 1 and 2 in a longitudinal section along the longitudinal axis,

4a the area IV in 3 in an enlarged view, showing the free end of clamping fingers with a clamping unit of the clamping device, wherein the clamping fingers are in their Spannfingerausgangsstellung,

4b the representation of the clamping fingers according to 4a , wherein the clamping fingers are in their Spannfingerarbeitsstellung and

5 the perspective view of the embodiment of the clamping device according to 1 in a partially sectioned partial representation without the foot.

In the figures, an embodiment of a clamping device 10 illustrated. The clamping device is used for clamping a test specimen inside 11 to measure, test or even process the test object. With the clamping device 10 especially very small samples 11 can be measured, for example, teeth in a dental laboratory. In particular, the tensioning device 10 to set up a candidate 11 inside in a bore of the specimen 11 to span, the hole example according to a diameter between 2.0 mm and 3.0 mm. The tensioning device 10 is in principle also suitable for smaller bore diameters of at least 1.8 mm in diameter.

The tensioning device 10 has a housing 12 , The example according to a cup-shaped, hollow cylindrical housing part 13 and a lid part 14 having. With the help of the cover part 14 becomes the interior 15 of the housing 12 or the housing part 13 locked.

The housing 12 and according to the housing part 13 is with one foot 16 connected, which serves the tensioning device 10 on a corresponding work table, for example, a turntable, set up. For aligning the clamping device 10 on the work table can be at the foot 16 several and according to three Ausrichtkörper 17 be arranged.

From the top of the foot 16 is a centering projection 18 away, in the case 12 and according to the example in an associated Zentrierausnehmung 19 on the housing part 13 intervenes. About the centering projection 18 and the centering recess 19 becomes the case 14 on the foot 16 centered so that it is aligned coaxially to a longitudinal axis L. The rotational position of the housing 12 about the longitudinal axis L results from several screw 20 with which the housing 12 at the foot 16 is attached.

The tensioning device 10 has a clamping unit 25 with several elastically deformable clamping fingers 26 on. The clamping fingers 26 are in a circumferential direction U about the longitudinal axis L through a gap or a slot 29 separated from each other and thus in the circumferential direction U spaced. This allows the chip fingers 26 independently of each other elastically bending away from the longitudinal axis L. Each clamping finger 26 extends from a free end 27 up to a ring part 28 the clamping unit 25 , In the transition from the ring part 28 to the clamping fingers 26 the slot ends 29 , each immediately adjacent clamping fingers 26 separates each other. By way of example, the clamping fingers 26 over the ring part 28 integrally connected without seam and joint. The clamping fingers 26 For example, can be prepared by a plurality of parallel to the longitudinal axis L extending slots in a hollow cylindrical output part 29 be introduced.

In the embodiment described here, the clamping unit 25 three in the circumferential direction U about the longitudinal axis L evenly spaced clamping fingers 26 on. In addition to this could also more than three clamping fingers 26 to be available. Due to the small dimensions of the clamping unit 25 it is advantageous if only three clamping fingers 26 available.

Each clamping finger 26 has on a remote from the longitudinal axis L radially outer side a clamping surface 30 that serves the examinee 11 to clamp for clamping. The clamping surface 30 closes, for example, directly to the free end 27 the clamping finger 26 at. For clamping a test object 11 become the tension fingers 26 in a bore, a recess, a cavity or the like of the specimen 11 introduced and the clamping fingers 26 are elastically deformed or bent away from the longitudinal axis L, so that the distance of the clamping surfaces 30 from the longitudinal axis L increases until the clamping surfaces 30 inside the test object 11 abut and apply this with a clamping force for clamping.

For elastic deformation of the clamping fingers 26 serves a spreader 31 , The spreader 31 has a both in the circumferential direction U about the longitudinal axis L, as well as in the direction of the longitudinal axis L curved spreading surface 32 on. The curvature of the spreading surface 32 in the circumferential direction U and / or the curvature of the spreading surface 32 in the direction of the longitudinal axis L are constant and can be the same or different sizes. In the embodiment, the spreading surface 32 formed by the surface of a spherical segment and, for example, the surface of a hemisphere, so that the spreading surface 32 has the shape of a spherical cap.

The spreader 31 is coaxial with the longitudinal axis L between the clamping fingers 26 arranged. The spreading surface 32 is due to the tension fingers 26 the clamping unit 25 at each of a loading area 33 at. Starting from the free end 27 a tension finger 26 the loading area runs 33 of the tension finger 26 inclined to the longitudinal axis L such that the distance between the loading surface 33 and the longitudinal axis L in a tensioning direction F parallel to the longitudinal axis L, starting from the free end 27 to the housing 12 decreases. By way of example, the loading areas are 33 the clamping finger 26 arranged on a common conical surface, which is arranged concentrically to the longitudinal axis L. The clamping surfaces 30 the clamping finger 26 lie on a common cylindrical surface about the longitudinal axis L, when the clamping fingers 26 their undeformed, not by the spreader 31 spread arm position A26. In the Spannfingerausgangsstellung A26 is the spreader 31 in the spreading body starting position A31 ( 4a ).

By shifting the spreader 31 along the longitudinal axis L in the clamping direction F, the spreader 31 be moved into a Spreizkörperarbeitslage E31. In Spreizkörperarbeitslage E31 are the clamping fingers 26 by elastic deformation at least following its free ends 27 in the area of the clamping surfaces 30 spread apart to a Innenspannen of the test specimen 11 to effect by the clamping surfaces 30 against an inner surface of the test piece 11 , For example, a hollow cylindrical surface, are pressed. In the Spreizkörperarbeitslage E31 take the Spannfinger 26 a clamping finger position E26 on ( 4b ).

To move the spreader 31 between the Spreizkörperausgangslage A31 and the Spreizkörperarbeitslage E31 is an actuating rod 37 ( 3 . 4a and 4b ). The operating rod 37 is with the example according to hemispherical spreader 31 connected. The operating rod 37 extends through the hollow cylindrical ring part 28 the clamping unit 26 through into the interior 15 of the housing 12 into it. In the ring part 28 is, for example, along the longitudinal axis L extending bore for carrying out the actuating rod 37 available.

The clamping unit 25 is at a head piece 38 of the lid part 14 attached. The head piece 38 has a cylindrical passage opening for receiving the ring member 28 , At the ring part 28 is an annular flange 39 trained with the help of in the head piece 38 Screwed screws against the head piece 38 pressed and fastened in this way.

Below the clamping unit 25 is in the interior 15 of the housing 12 a first coupling body 40 arranged, the example has a substantially cylindrical shape. The operating rod 37 is with the first coupling body 40 connected. For this purpose, the first coupling body 40 in the embodiment a clamping slot 41 on, in which the operating rod 37 is plugged in. A clamping screw 42 ensures a force-locking holding the confirmation bar 37 in the clamping slot 41 of the first coupling body 40 ,

For receiving a portion of the first coupling body 40 has the head piece 38 a cylindrical receiving space 43 on. Of the accommodation space 43 is on the clamping unit 25 opposite side open, with the head piece 38 on this side a mounting flange 44 having, with it on an annular end wall part 45 of the lid part 14 fastened, for example by a screw connection. The front wall part 45 is detachable on the housing part 13 attached.

The front wall part 45 is coaxial with the longitudinal axis of a cylindrical guide recess 46 interspersed, through which the first coupling body 40 extends through and through the first coupling body 40 is mounted movably guided along the longitudinal axis L in the clamping direction F and opposite in the release direction R. The guide recess 46 opens into a radially enlarged recess portion 47 one. In the transition area between the guide recess 46 and the recess portion 47 is thus an annular shoulder 48 at the end wall part 45 or on the housing 12 educated.

On the ring shoulder 48 opposite side is the recess portion 47 through the mounting flange 44 limited. In the recess section 47 protrudes from the lateral surface of the cylindrical first coupling body 40 at least one radial projection 49 into it. The radial projection 49 is executed, for example, as a coaxially extending around the longitudinal axis L ring. In a modification to this, several separate radial projections could also be distributed in the circumferential direction U. 49 to be available. At the radial projection 49 is on the ring shoulder 48 facing side a stop surface 50 educated.

The ring shoulder 49 forms one with the stop surface 50 interacting counter surface 51 , The counter surface 51 and the stop surface 50 provide a limiting device 52 which is adapted to the maximum clamping path S of the first coupling body 40 and hence the spreader body 31 in clamping direction F to limit. The maximum tensioning path S is reached when the stop surface 50 at the counter surface 51 is applied. Another shift of the coupling body 40 in the tensioning direction F is then prevented. In turn, this leads to a movement of the spreader 31 in clamping direction F is no longer possible and further deformation of the clamping fingers 26 is avoided. This ensures that the deformation of the clamping fingers 26 always elastic and not plastic. The clamping fingers 26 can thus move back from the Spannfingerarbeitsstellung E26 in the Spannfingerausgangsstellung A26.

The limitation device 52 requires one for this functionality on the housing 12 existing counter area 51 and one on the first coupling body 40 associated stop surface 50 , In a modification to the illustrated embodiment, other structural configurations can be used for this purpose.

In the case 12 and according to example in the housing part 13 is a second coupling body 56 slidably mounted along the longitudinal axis L. In the embodiment, the second coupling body is located 56 for this purpose on the inner wall of the housing part 13 and is at least partially cylindrical.

The second coupling body 56 is about a force generating unit 57 with the first coupling body 40 coupled. The force generation unit 57 creates a tensile force between the two coupling bodies 40 . 56 and has in the embodiment for this purpose a tension spring 58 on. In a modification to this, several tension springs or other traction means could be present, by means of which a tensile force between the two coupling bodies 40 . 56 can be generated.

The one, first end 59 the tension spring 58 is directly on the first coupling body 40 attached. That with the first end 59 the tension spring 58 connected ends 60 of the first coupling body 40 is in a guide recess 61 of the second coupling body 56 slidably received along the longitudinal axis L.

The other, second end 62 the tension spring 58 is about a tensile force adjustment unit 63 with the second coupling body 56 coupled. The tensile force adjustment unit 63 has a first adjustment part 64 on, immediately with the second end 62 the tension spring is connected. The first adjustment part 64 is relative to the second coupling body 56 parallel to the longitudinal axis L slidable in a Einstellaussparung 65 of the second coupling body 56 stored. The first adjustment part 64 can be secured against rotation in the circumferential direction U. The first adjustment part 64 is by way of example by an adjusting sleeve 66 formed the second end 62 the tension spring 58 encloses.

A second adjustment part 67 is rotatably arranged in the circumferential direction U about the longitudinal axis L and is supported on the first coupling body 40 opposite side of the second coupling body 56 sliding off. The second adjustment part 67 is as adjusting nut 68 executed and is an internal thread with an external thread of the first adjustment 64 or the adjusting sleeve 66 screwed. By a relative rotation of the second adjustment 67 or the adjusting nut 68 opposite the first adjusting part 64 or the adjusting sleeve 66 can the distance between both ends 59 . 62 the tension spring 58 varies and thus the tensile force between the two coupling bodies 40 . 56 be set.

The two adjustment parts 64 . 67 are arranged coaxially with the longitudinal axis L. The tension spring 58 is in a central recess 69 of the second coupling body 56 received, which extends coaxially to the longitudinal axis L and, for example, the guide recess 61 with the adjustment recess 65 combines.

The tensioning device 10 also has a return device in the embodiment 74 on which a restoring force on one of the two coupling body 40 . 56 and in the embodiment of the second coupling body 56 exercises. The restoring force acts in the release direction R, opposite to the clamping direction F. The restoring force urges the second coupling body 56 in a coupling body starting position A56. For this purpose, the reset device 74 in the embodiment, a compression spring 75 on or is by the compression spring 75 educated. In a modification to this, other force generating means could be used to generate the restoring force. It can also spring packs with more than one compression spring 75 be used.

The compression spring 75 is arranged coaxially to the longitudinal axis L. It relies on the one hand on the housing 12 and according to the housing part 13 and on the other hand indirectly or directly on one of the two coupling body. In the embodiment, the compression spring is supported 75 via the adjusting nut 68 on the second coupling body 56 from.

In a further modification to the described embodiment, the restoring force could also be effected by a tensile force instead of a compressive force.

Around the coupling body starting layer A56 for the second coupling body 56 pretend, the tensioning device 10 a position adjustment device 76 on. The position adjustment device 76 has in the embodiment for this purpose a position adjustment 77 which extends parallel to the longitudinal axis L and in the housing 12 and according to the end wall part 55 is arranged. The free end of the position adjustment screw 77 is the second coupling body 56 assigned and is located on the second coupling body 56 when it assumes its coupling body starting position A56. About the restoring force of the compression spring 75 becomes the second coupling body 56 against the position adjustment screw 77 crowded. The restoring force is always greater than zero when the second coupling body 56 is located outside of its coupling body starting position A56. In the coupling body starting position A56 itself, the restoring force may be greater than or equal to zero.

In a modification of the embodiment shown here could instead of Positionsseinstellschraube 77 also another suitable position adjustment body 78 be used.

For operation of the clamping device 10 serves an operating device 80 , The operating device 80 has a control panel 81 the example as a control ring 82 is executed. The control panel 81 or the operating ring 82 is from outside the case 12 accessible and, for example, outside the housing 12 or on the housing part 13 slidably mounted in the clamping direction F and in the release direction R. In addition, the operating ring 82 For example, in the circumferential direction U in a predetermined rotation angle range around the housing 12 and according to the housing part 13 to be turned around.

The operating ring 82 is over at least one and example according to several fasteners 83 with the second coupling body 56 coupled. The connecting elements 83 are in the embodiment by connecting pins 84 educated. The connecting pins 84 are fixed to the second coupling body 56 connected and screwed in there, for example. They pass through the housing part 13 and protrude into the operating ring 82 into it. To a movement of the operating ring 82 in the tensioning direction F and in the release direction R, is for each connecting pin 84 in the housing part 13 a Axiallangloch 85 present, so that the axial movement parallel to the longitudinal axis L of the operating ring 82 through the housing part 13 can take place unhindered.

The connecting pins 84 each protrude into an associated circumferential long hole 86 in the operating ring 82 into it. This is a rotational movement of the operating ring 82 in the circumferential direction U about the longitudinal axis L in the predetermined rotation angle range possible without this rotational movement of the operating ring 82 on the second coupling body 56 is transmitted. Parallel to the longitudinal axis L is the size of the circumferential long hole 86 to the diameter of the connecting pin 84 adapted to achieve a movement coupling in the release direction R and tension direction F.

The operating ring 82 is displaceable from an operating ring starting position A82 into a operating ring working position E82 in the tensioning direction F ( 2 ). By this shift of the operating ring 82 also becomes the second coupling body 56 from its coupling body starting position A56 into the coupling body working position E56 of the tensioning unit 25 moved away. About the tensile force of the tension spring 58 This movement will be on the first coupling body 40 and over the operating rod 37 on the spreader 31 transferred, which is thus moved from its Spreizkörperausgangslage A31 in its Spreizkörperarbeitslage E31 and thus the clamping fingers 26 out its clamping finger starting position A26 in the Spannfingerarbeitsstellung E26 transferred.

To the spreader 31 to hold in its Spreizkörperarbeitslage E31, has the tensioning device 10 a holding device 90 on. The holding device 90 works in the embodiment with the control panel 81 or the operating ring 82 together. The holding device 90 has a holding part for this purpose 91 and a counterpart part 92 on. The holding part 91 is as a retaining projection 93 executed, which is fixed to the operating ring 82 is connected and from the inner surface of the operating ring 82 in a guide groove or groove 94 on the outside of the housing part 13 intervenes. The groove 94 is schematic in the 2 and 5 illustrated. It has an axial section 94a on, which extends parallel to the longitudinal axis L, and a subsequent to the axial section peripheral portion 94b in the housing part 13 extends in the circumferential direction U about the longitudinal axis L. In the operating ring starting position A82 is the retaining projection 93 in the axial section 94a the groove 94 , The holding device 90 is in a neutral position in which it is a movement of the control panel 81 or the operating ring 82 in release and tensioning direction R, F permits. One turn of the control panel 81 or the operating ring 82 in the circumferential direction U about the longitudinal axis L is not possible in the neutral position, if the retaining projection 93 an axial distance to the peripheral portion 94b having.

When the operating ring 82 is moved in its operating ring working position E82 in the clamping direction F, the retaining projection passes 93 seen parallel to the longitudinal axis L to the same height as the peripheral portion 94b the groove 94 , In this operating ring operating position E82, the operating ring 82 are rotated in the circumferential direction U to the retaining projection 93 in the peripheral section 94b the groove 94 to move. Attacks the retaining projection 93 in the peripheral section 94b a, the holding device is in a holding position. The operating ring 82 is in its operating ring working position E82 contrary to the restoring force of the return device 74 and the tensile force of the force generating means 57 held axially deflected. A movement of the operating ring 82 in the release direction R is prevented. In this operating ring working position E82, the first coupling body takes 40 its coupling body work position and the spreader body 31 his spreader working posture E31. In the coupling body working position of the first coupling body 40 or in the Spreizkörperarbeitslage E31 of the expansion body 31 is the limiting device 52 preferably not effective. In particular, the stop surface has 50 a distance to the counter surface 51 , This ensures that the clamping fingers without prior limitation of the clamping finger movement by the limiting device 52 Take the clamping finger position E26 and a sufficient clamping force on the test object 11 exercise.

Will the operating ring 82 parallel to the longitudinal axis L in alignment with the axial section 94a the groove 94 aligned (neutral position of the holding device 90 ), causes the restoring force of the return device 74 a movement of the second coupling body 56 together with the operating ring 82 in the release direction R, wherein also the first coupling body 40 and with this the spreader 31 is moved back into its Spreizkörperausgangslage A31.

In the embodiment thus serve the retaining projection 93 as a holding part 91 and the peripheral portion 94b the groove 94 as a counterpart 92 the holding device 90 , The holding device 90 can be switched between the neutral position and the holding position.

LIST OF REFERENCE NUMBERS

10

 jig

11

 examinee

12

 casing

13

 housing part

14

 cover part

15

 Interior of the housing

16

 foot

17

 alignment body

18

 centering

19

 centering

20

 screw

25

 clamping unit

26

 clamping finger

27

 free end

28

 ring part

29

 slot

30

 clamping surface

31

 spreader

32

 spreader

33

 actuating area

37

 actuating rod

38

 headpiece

39

 annular flange

40

 first coupling body

41

 clamping slot

42

 clamping screw

43

 accommodation space

44

 mounting flange

45

 End wall part

46

 guide recess

47

 recess

48

 annular shoulder

49

 radial projection

50

 stop surface

51

 counter surface

52

 limiting device

56

 second coupling body

57

 Force generating unit

58

 mainspring

59

 first end of the tension spring

60

 End of the first coupling body

61

 guide recess

62

 second end of the tension spring

63

 Zugkrafteinstelleinheit

64

 first adjustment part

65

 Einstellaussparung

66

 adjusting

67

 second adjustment part

68

 adjusting

69

 central recess

74

 Reset device

75

 compression spring

76

 position adjustment

77

 position adjusting

80

 operating device

81

 control panel

82

 operating ring

83

 connecting element

84

 connecting pin

85

 Axialllangloch

86

 Perimeter slot

90

 holder

91

 holding part

92

 Brace part

93

 retaining projection

94

 groove

94a

 axial

94b

 peripheral portion

A26

 Clamping fingers initial position

A31

 Spreizkörperausgangslage

A56

 Coupling body starting position

A82

 Operating loop starting position

E26

 Clamping fingers working position

E56

 Coupling body working position

E31

 Spreizkörperarbeitslage

E82

 Operating ring working position

F

 tensioning direction

L

 longitudinal axis

R

 release direction

S

 maximum tension travel

U

 circumferentially

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1812525 A [0002]
• DE 4113449 C1 [0003]

Claims (19)

Clamping device ( 10 ) for internal clamping of a test object ( 11 ), with a coaxially to a longitudinal axis (L) arranged clamping unit ( 10 ), which several by means of an expansion body ( 31 ) radially outwardly from the longitudinal axis (L) away spreadable clamping fingers ( 26 ) each having a radially outwardly of the longitudinal axis (L) aligned clamping surface ( 30 ) and one of the longitudinal axis (L) facing impingement surface ( 33 ), wherein the distance of each loading surface ( 33 ) with respect to the longitudinal axis (L) starting from the free end ( 27 ) of the clamping finger ( 26 ) decreases along the longitudinal axis (L) in a clamping direction (F), wherein the expansion body ( 31 ) a spreading surface ( 32 ), with which he at the admission areas ( 33 ) and wherein the expansion body ( 31 ) having an outer end extending along the longitudinal axis (L) into an interior space ( 15 ) of a housing ( 12 ) of the tensioning device ( 10 ) extending actuating rod ( 37 ), with one in the interior ( 15 ) of the housing ( 12 ) and along the longitudinal axis (L) movably mounted first coupling body ( 40 ), with which the actuating rod ( 37 ), with one in the interior ( 15 ) of the housing ( 12 ) and along the longitudinal axis (L) relative to the first coupling body ( 40 ) movably mounted second coupling body ( 56 ), with a force generating unit ( 57 ), the two coupling bodies ( 40 . 56 ) and with an operating device ( 80 ), by means of which the second coupling body ( 56 ) in the clamping direction (F) parallel to the longitudinal axis (L) for internal clamping of the test piece ( 11 ) is movable. Clamping device according to claim 1, characterized in that the expansion body ( 31 ) a in the direction of the longitudinal axis (L) and about the longitudinal axis curved spreading surface ( 32 ), with which the expansion body ( 31 ) when spreading apart the clamping fingers ( 26 ) on the clamping fingers ( 26 ) is present. Clamping device according to claim 2, characterized in that the curvature of the spreading surface ( 32 ) about the longitudinal axis (L) and / or the curvature of the spreading surface ( 32 ) is constant in the direction of the longitudinal axis (L). Clamping device according to claim 2 or 3, characterized in that the spreading surface ( 32 ) has the shape of a spherical cap. Clamping device according to one of the preceding claims, characterized in that a limiting device ( 52 ) is present, the maximum clamping path of the first coupling body ( 40 ) and / or the expansion body ( 31 ) along the longitudinal axis (L) in the clamping direction (F) limited. Clamping device according to claim 5, characterized in that the limiting device ( 52 ) at least one on the first coupling body ( 40 ) existing obliquely or at right angles to the longitudinal axis (L) aligned stop surface ( 50 ) having a counter surface ( 51 ) on the housing ( 12 ) whose position is the maximum clamping path (S) of the first coupling body ( 40 ) and / or the expansion body ( 31 ) in the tensioning direction (F). Clamping device according to one of the preceding claims, characterized in that a restoring device ( 74 ) is present, which has a restoring force parallel to the longitudinal axis (L) in a clamping direction (F) opposite release direction (R) on the first coupling body ( 40 ) and / or the second coupling body ( 56 ) is applied to the first coupling body ( 40 ) and / or the second coupling body ( 56 ) into a coupling body starting layer (A56). Clamping device according to one of the preceding claims, characterized in that a position adjustment device ( 76 ) having a coupling body starting layer (A56) of the first coupling body (A56) 40 ) and / or the second coupling body ( 56 ) pretends. Clamping device according to claim 7 and 8, characterized in that the position adjustment device ( 76 ) one parallel to the longitudinal axis (L) positionable on the housing ( 12 ) Positionseinstellkörper arranged ( 78 ) having a stop for the first coupling body ( 40 ) and / or the second coupling body ( 56 ) against which the first coupling body ( 40 ) and / or the second coupling body ( 56 ) is urged by the restoring force. Clamping device according to one of the preceding claims, characterized in that the force-generating unit ( 57 ) at least one tension spring ( 58 ) whose one end ( 59 ) with one of the two coupling bodies ( 40 ) and the other end ( 62 ) via a tensile force adjustment unit ( 63 ) with the respective other coupling body ( 56 ) connected is. Clamping device according to claim 10, characterized in that the Zugkrafteinstelleinheit ( 63 ) in the direction parallel to the longitudinal axis (L) slidably mounted first adjusting part ( 64 ) and a rotatable about the longitudinal axis (L) mounted second Einstellteil ( 67 ), which are connected to each other by means of a thread and that the Tension spring ( 58 ) with the first adjusting part ( 64 ) connected is. Clamping device according to claim 11, characterized in that the first adjusting part ( 64 ) against rotation and parallel to the longitudinal axis (L) displaceable on the second coupling body ( 56 ) is stored. Clamping device according to claim 11 or 12, characterized in that the second adjusting part ( 67 ) slidably on the second coupling body ( 56 ) is supported. Clamping device according to one of the preceding claims, characterized in that the operating device ( 80 ) a control panel ( 81 ), the outside of the housing ( 12 ) and slidably disposed parallel to the longitudinal axis (L). Clamping device according to claim 14, characterized in that the operating part ( 81 ) arranged coaxially with the longitudinal axis (L) and sliding outside the housing ( 12 ) mounted control ring ( 82 ) is formed. Clamping device according to claim 14 or 15, characterized in that the operating part ( 81 ) via at least one connecting element ( 83 ) parallel to the longitudinal axis (L) with the second coupling body ( 56 ) is motion coupled. Clamping device according to one of claims 14 to 16, characterized in that the operating part ( 81 ) in the circumferential direction (U) about the longitudinal axis (L) relative to the second coupling body ( 56 ) is movable at least in a predetermined rotation angle range. Clamping device according to one of claims 14 to 17, characterized in that a holding device ( 90 ) is present, the at least one on the control panel ( 81 ) existing holding part ( 91 ) and one each on the housing ( 12 ) existing associated counterpart part ( 92 ), wherein the holding device ( 90 ) can be brought into a holding position when the second coupling body ( 56 ) in a coupling body working position (E56), and engage in the holding position such that a movement of the second coupling body ( 56 ) in a clamping direction (F) opposite release direction (R) from the Kopplungskörperarbeitslage (E56) out in the direction of a Kopplungskörperausgangslage (A56) is prevented. Clamping device according to claim 18, characterized in that the holding device ( 90 ) can be brought into a neutral position in order to prevent a movement of the second coupling body ( 56 ) in the release direction (R) and / or tension direction (F) between the coupling body starting layer (A56) and the coupling body working layer (E56).

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