DE102008043902A1 - Screw wrench for e.g. star-like work piece, has clamping parts with groups that have common tangents arranged on three sides of hexagon, where distance from third part up to wall of hole is larger than length of largest diagonals of hexagon - Google Patents

Abstract

The wrench has a drive head (100) arranged at ends of a handle (10). Clamping parts are connected with a retaining groove (12) over a sliding surface. The surface and the groove define an area in which a convex part of a star-like work piece is retained. Groups of the parts have common tangents arranged on three sides of a hexagon. A center point of a circle to be tangent to sides of the hexagon is provided at a distance from a center point of a retaining hole (18). Distance from a third clamping part (114) up to a wall of the hole is larger than length of largest diagonals of the hexagon.

Description

Technical area

The The present invention relates to a wrench, In particular, a wrench attached to a Workpiece in various forms can be plugged and this to rotate, with the return movement immediately inside its drive head is enabled, and the Ease of use is improved.

State of the art

Out WO 9838009 a wrench is known, wherein a return movement is made possible directly in the interior of its drive head, a number of grooves E1 to E6 with different circular arc and a number of clamping surfaces P1 to P7 are arranged alternately on the circumference of the action end of the stirrup wrench. When the wrench is attached to a hexagonal workpiece ( 3 ), three clamping surfaces are pressed against three sides of the workpiece, and some corner parts of the workpiece are received in the receiving grooves. When the wrench is turned at an angle and it is necessary to make a return movement ( 4 to 7 ), the receiving grooves and the clamping surfaces of the stirrup wrench are separated by the counterclockwise rotation in order from the side surfaces and the corner parts of the hexagonal workpiece. After the wrench has been set at a reasonable angle, the wrench is re-attached to the hexagonal workpiece to further propel the latter to rotate. Since the workpiece usually has a hexagonal shape with a metric or English dimension, or a gear shape or a star shape, normally the workpieces to be rotated are in the form of a hexagon with a metric dimension of 19 mm, in the form of a hexagon with English dimension of 3/4 inch, in the form of a gear with a measure after DIN, 19 and in star shape with a measure DIN, E24 grouped in a group as their measurements approach. Likewise, the workpieces to be turned are in the form of a hexagon with a metric dimension of 18 mm, in the form of a hexagon with an English dimension of 11/16 inch, in the form of a gear with a measure of DIN, 18 and in star shape with measurements DIN, E22 grouped in a group. But if a suitable wrench is used for attachment to the workpieces of a group, correspondingly different deviations are present, which are irregular. Therefore, the off WO 9838009 Known wrench are plugged only on the hexagonal shape to be driven workpiece, because no corresponding improvement over the existing in the prior art deficiencies and it is impossible with such wrench, the problem of occurring when attaching to the workpieces in different forms different deviations to solve.

Compared with the deficiencies present in the abovementioned disclosure, the inventor has developed an improved socket key and corresponding patent applications (US Pat. US 7107879 and TW M269141 ) made. The improvement is essentially that the clamping surfaces and the receiving grooves are arranged in order on the inner peripheral wall of the action end of the socket wrench, wherein a concave receiving groove between each two adjacent clamping surfaces is provided, and a concave groove in the central region of each clamping surface is arranged , Thus, the Aufsteckschlüssel can be attached to the workpieces in some forms, so that its scope is extended. The out US7107879 and TW M269141 known Aufsteckschlüssel has the following advantages: the Aufsteckschlüssel has a large bending radius and a small bending radius, wherein the clamping surface has the large bending radius, and the receiving groove has the small bending radius; in addition, since a concave groove is provided on the large bending radius clamping surface, the clamping surface, the receiving groove and the concave groove are arranged in order on the inner circumference of the socket wrench, so that the socket wrench can be attached to the workpieces in various shapes as shown in FIG 3 to 11 from US7107879 and TW M269141 shown. Such a Aufsteckschlüssel has the following disadvantages: when the Aufsteckschlüssel is attached to the workpiece to be driven for turning, this is rotated at a certain angle and it is necessary to perform a return movement, the Aufsteckschlüssel must be completely removed in the axial direction of the workpiece, so that a return movement is possible. Only when the complete return movement has been carried out and the Aufsteckschlüssel has been re-attached to the workpiece, the workpiece can be further driven to rotate. The repetition of the attachment and the removal is time consuming. Therefore, it is necessary to improve such a Aufsteckschlüssel.

Content of the invention

The present invention has for its object to provide a wrench which is attachable to a workpiece in various forms to drive the last to rotate, with a return movement is made possible directly inside the action end, so that the ease of use is improved. He inventive wrench is a drive head arranged on the handle. The drive head has an attachment opening, wherein three clamping surfaces and three receiving grooves are arranged alternately on the inner peripheral wall of the push-on opening. The space defined by the receiving groove is sufficient to receive a convex part of a star-shaped workpiece. A concave groove is disposed in the middle region of each clamping surface. Each clamping surface is divided by the one concave groove in a first clamping part and a second clamping part, which first and second clamping part are symmetrical to each other with respect to the center of the concave groove. An inner flank of the receiving groove located in the last position is connected to the second clamping part. One of the inner edge opposite outer edge of this receiving groove is connected to a third clamping part, whose shape corresponds to the shape of the first clamping part. The defined by the concave groove space is sufficient to receive a convex part of the star-shaped workpiece. The clamping part and the receiving groove are connected to each other via a sliding surface in a gently inclined manner. A space defined by the sliding surface and the receiving groove is sufficient to receive a convex part of the star-shaped workpiece. Each group of opposing first and second clamp members has a common tangent, and three common tangents are on three sides of a hexagon.

Brief description of the drawings

1 Wrench according to the present invention in perspective view;

2 Wrench according to the present invention in front view;

3 A wrench according to the present invention, wherein a hexagonal workpiece is driven to rotate;

4 Wrench according to the present invention shown in a first view, wherein a return movement is performed;

5 Wrench according to the present invention shown in a second view, wherein a return movement is performed;

6 Wrench according to the present invention shown in a third view, wherein a return movement is carried out;

7 Wrench according to the present invention shown schematically, wherein the wrench is again attached to the workpiece;

8th Wrench according to the present invention shown schematically, wherein a star-shaped workpiece is driven for rotation;

9 Wrench according to the present invention shown schematically, wherein a gear-shaped workpiece is driven for rotation;

10 Wrench according to the present invention shown schematically, wherein a square workpiece is driven for rotation;

11 A second embodiment of the present invention is shown in perspective view;

12 A third embodiment of the present invention is shown in a perspective view;

13 Wrench according to the third embodiment of the present invention when turning shown schematically;

14 a fourth embodiment of the present invention shown in front view;

15 a fifth embodiment of the present invention shown in front view, and

16 a sixth embodiment of the present invention shown in perspective view.

Preferred embodiment

following For example, the present invention will be described with reference to the drawings Embodiments explained in more detail.

• – einen Griff 10, der ein gegenüberliegendes erstes und ein zweites Ende aufweist, an welchem ersten Ende ein Antriebskopf 100 angeordnet ist, welcher Antriebskopf 100 eine durchgehende Öffnung 14 aufweist und mittels der durchgehenden Öffnung 14 an einem anzutreibenden Werkstück 20 aufsteckbar ist, und die durchgehende Öffnung 14 umfasst:
• – eine kreisbogenförmige Aufnahmeöffnung 18, in der das anzutreibende Werkstück 20 drehbar aufgenommen ist;
• – eine Aufstecköffnung 19, die der Aufnahmeöffnung 18 gegenüberliegt und mit der Aufnahmeöffnung 18 verbunden ist, wobei drei Klemmflächen 11 und drei Aufnahmenuten 12 an der inneren Umfangswand der Aufstecköffnung 19 um ihre zentrale Längsachse wechselweise angeordnet sind, die in Längsrichtung verlaufende Erstreckung der Klemmflächen 11 und der Aufnahmenuten 12 parallel zu der zentralen Längsachse angeordnet ist, die Klemmflächen 11 sich auf einer Bogenfläche befindet, derer Mittelbereich in Richtung der zentralen Längsachse nach und nach vorspringt, die Aufnahmenut 12 zwei symmetrische und bogenförmige Flanken 120 aufweisen, und ein von der Aufnahmenut 12 definierter Raum ausreicht, einen konvexen Teil 31 eines sternförmigen Werkstücks 30 aufzunehmen; jeweils eine konkave Nut 13 in dem mittleren Bereich jeder Klemmfläche 11 angeordnet ist, die Form der konkaven Nut 13 anders als die Form der Aufnahmenut 12 gestaltet ist, die in Längsrichtung verlaufende Erstreckung der konkaven Nut 13 parallel zu der zentralen Längsachse angeordnet ist, jede Klemmfläche 11 durch die eine konkave Nut 13 in einem ersten Klemmteil 110 und einem zweiten Klemmteil 111 geteilt ist, welcher erste und zweite Klemmteil 110, 111 symmetrisch zueinander in Bezug auf die Mitte der konkaven Nut 13 sind, eine innere Flanke der in der letzten Position liegenden Aufnahmenut 12 mit dem zweiten Klemmteil 111 verbunden ist, die der inneren Flanke gegenüberliegende äußere Flanke mit einem dritten Klemmteil 114 verbunden ist, dessen Form der Form des ersten Klemmteils 110 entspricht, die konkave Nut 13 zwei gegenüberliegende Flanken 131 und eine mit den beiden Flanken 131 verbundene konkave Bodenfläche 132 umfasst, die Öffnungsweite der konkaven Nut 13 zwischen den beiden Flanken 131 ausreicht, den konvexen Teil 31 des sternförmigen Werkstücks 30 aufzunehmen, eine bogenförmige Führungsfläche 113 in dem Bereich der Verbindung jedes Klemmteils 110, 111 mit der Flanke 131 der konkaven Nut 13 gebildet ist, und der Klemmteil 110, 111 mit der Aufnahmenut 12 über eine Rutschfläche 121 in sanft geneigter Weise verbunden ist, die Rutschfläche 121 und die Aufnahmenut 12 einen Raum definieren, in dem der konvexe Teil 31 des sternförmigen Werkstücks 30 aufnehmbar ist, eine Gruppe des gegenüberliegenden ersten und des zweiten Klemmteils 110, 111 eine gemeinsame Tangente aufweist, drei gemeinsame Tangenten auf drei Seiten von einem Hexagon A liegen, der Mittelpunkt C eines von den Seiten des Hexagons A tangierten Kreises von dem Mittelpunkt D der Aufnahmeöffnung 18 in einem Abstand entfernt ist, die weiteste Entfernung H3 von dem dritten Klemmteil 114 bis zur Wand des Aufnahmeraumes 18 größer als die Länge der größten Diagonale von dem Hexagon A ist.

As in 1 to 3 illustrated, the wrench comprises according to the present invention:

• - a handle 10 having an opposite first and second end, at which first end a drive head 100 is arranged, which drive head 100 a continuous opening 14 and by means of the through opening 14 on a workpiece to be driven 20 attachable, and the through opening 14 includes:
• - A circular-shaped receiving opening 18 in which the workpiece to be driven 20 is received rotatably;
• - An insertion opening 19 that the receiving opening 18 opposite and with the receiving opening 18 is connected, with three clamping surfaces 11 and three recording grooves 12 on the inner peripheral wall of the push-on opening 19 are arranged alternately about their central longitudinal axis, extending in the longitudinal direction extension of the clamping surfaces 11 and the recording grooves 12 is arranged parallel to the central longitudinal axis, the clamping surfaces 11 is located on an arcuate surface, the central region in the direction of the central longitudinal axis gradually protrudes, the receiving groove 12 two symmetrical and arcuate flanks 120 and one from the receiving groove 12 defined space is sufficient, a convex part 31 a star-shaped workpiece 30 record; each a concave groove 13 in the middle region of each clamping surface 11 is arranged, the shape of the concave groove 13 unlike the shape of the receiving groove 12 is designed, the longitudinal extent of the concave groove 13 is arranged parallel to the central longitudinal axis, each clamping surface 11 through the one concave groove 13 in a first clamping part 110 and a second clamping part 111 divided, which first and second clamping part 110 . 111 symmetrical to each other with respect to the center of the concave groove 13 are an inner edge of the receiving groove in the last position 12 with the second clamping part 111 is connected, the inner edge of the opposite outer edge with a third clamping part 114 whose shape is the shape of the first clamping part 110 corresponds to the concave groove 13 two opposite flanks 131 and one with the two flanks 131 connected concave bottom surface 132 includes, the opening width of the concave groove 13 between the two flanks 131 sufficient, the convex part 31 of the star-shaped workpiece 30 an arcuate guide surface 113 in the region of the connection of each clamping part 110 . 111 with the flank 131 the concave groove 13 is formed, and the clamping part 110 . 111 with the receiving groove 12 over a sliding surface 121 connected in a gently inclined manner, the sliding surface 121 and the receiving groove 12 define a space in which the convex part 31 of the star-shaped workpiece 30 is receivable, a group of opposite first and second clamping part 110 . 111 has a common tangent, three common tangents lie on three sides of a hexagon A, the center C of a circle tangent to the sides of the hexagon A from the center D of the receiving opening 18 is removed at a distance, the farthest distance H3 from the third clamping part 114 to the wall of the recording room 18 greater than the length of the largest diagonal of the hexagon A is.

As in 3 to 10 is shown, the plug-in opening 19 with the above configuration in the operation of the wrench according to the present invention not only on the hexagonal workpiece 20 , but also on the gear-shaped workpiece 40 , on the star-shaped workpiece 30 and on the square workpiece 50 , as well as attachable to the workpiece in various forms. When performing the return movement, it is possible to work the workpiece 20 ; 30 ; 40 ; 50 in the receiving opening 18 to move. After the workpiece 20 ; 30 ; 40 ; 50 has been retreated at a desired angle, the wrench by means of the mounting opening 19 again on the workpiece 20 ; 30 ; 40 ; 50 attached to the workpiece 20 ; 30 ; 40 ; 50 continue to drive to turn.

In 3 a wrench according to the present invention is shown schematically, wherein the drive head 100 by means of its plug-in opening 19 on a hexagonal workpiece 20 is attached, the first, the second and the third clamping part 110 . 111 . 114 against four side surfaces of the hexagonal workpiece 20 are pressed, and three corner parts of the hexagonal workpiece 20 in the reception 12 are included. In this case, the hexagonal workpiece 20 be effectively driven to rotate in a clockwise direction.

As in 4 shown when the hexagonal workpiece 20 is rotated at an angle and a return movement is required, the drive head 100 turned counterclockwise. A corner part of the hexagonal workpiece 20 is from the receiving groove 12 separated. The sixth (numbered clockwise) clamping part 111 comes over the corner part of the hexagonal workpiece 20 over, and the workpiece 20 is towards the center of the receiving opening 18 emotional. The drive head 100 is turned counterclockwise. The seventh (numbered clockwise) clamp part 110 continues over the corner part of the hexagonal workpiece 20 over, as in 5 shown. Since the length of the largest diagonal of the hexagon A is smaller than the length of H3, the side surfaces and corner parts of the hexagonal workpiece become 20 from the clamp in the plug-in opening 19 free and the workpiece 20 gets into the interior of the receiving opening 18 moves, and the workpiece 20 is opposite the drive head 100 freely rotatable (see 6 ).

As in 7 shown, when the above-mentioned return movement is completed, the drive head 100 then against the workpiece 20 Turned clockwise and by means of the plug-in opening 19 again on the hexagonal workpiece 20 attached, namely the first, the second and the third clamping part 110 . 111 . 114 will be about four surfaces of the hexagonal workpiece 20 pressed, and three corner parts of the hexagonal workpiece 20 be in the receptions 12 added. In this case, the drive head 100 again capable of the hexagonal workpiece 20 effective to propel to turn.

In 8th the wrench according to the present invention is shown schematically, wherein the drive head 100 on a star-shaped workpiece 30 with a measure according to DIN, E is attached, three convex parts 31 of the star-shaped workpiece 30 in three grooves 12 are clamped so that the star-shaped workpiece 30 can be driven to rotate.

As in 9 illustrated when the wrench according to the present invention on a gear-shaped workpiece 40 is plugged, because clamping surfaces 11 , Recording grooves 12 and concave grooves 13 in the plug-in opening 19 are provided, are three convex teeth parts 41 of the gear-shaped workpiece 40 in the reception 12 while the other three convex teeth parts 41 in the concave grooves 13 are included. In this case, the gear-shaped workpiece 40 be effectively driven to rotate.

As in 10 shown when the wrench according to the present invention on a square workpiece 50 is plugged, because clamping surfaces 11 , Recording grooves 12 and concave grooves 13 in the plug-in opening 19 provided and arranged alternately on the circumference, are two corner parts of the square workpiece 50 each in a receiving groove 12 and a concave groove 13 taken, and are in the last position lying first clamping part 110 and the third clamping part 114 against two side surfaces of the square workpiece 50 pressed. In the present invention, the square workpiece 50 be effectively driven to rotate.

As in 11 shown, is a fork-shaped drive head 16 at the second end of the handle 10 arranged so that the handle 10 has at its two ends the function of effectively driving a workpiece to rotate.

As in 12 and 13 shown, has the receiving groove 12 at a lying in the axial direction end a limiting part 15 on, leaving the end of the receiving groove 12 closed is. When the plug-in opening 19 on the hexagonal workpiece 20 is attached to drive the last to rotate, are three corner parts of the hexagonal workpiece 20 in the reception 12 taken up and from the boundary part 15 limited to the drive head 100 before separation from the workpiece 20 to protect.

In 14 a further embodiment of the present invention is shown, wherein a slip-on 19 on the drive head 100 is arranged, the slip-on 19 designed in C-shape, by means of which Aufstecköffnung 19 the drive head 100 on a workpiece 20 is pluggable. The inner peripheral wall of the plug-in opening 19 the same as the ones in 2 is shown, wherein three clamping surfaces 11 , three recording grooves 12 , three first clamping parts 110 , three second clamping parts 111 and a third clamping part 114 distributed on the inner peripheral wall are arranged. Thus, the present invention can also be performed as a wrench.

As in 15 is shown, in each case a drive head 100 at both ends of the handle 10 arranged, wherein the one drive head 100 same as the one in 2 shown is designed and the other drive head 101 same as the one in 14 is designed illustrated. The operator can choose one of the two drive heads as desired.

As in 16 is an interruption 17 on a side wall of the receiving opening 18 arranged so that the through opening 14 designed in C-shape. Thus, the present invention can also be performed as a wrench.

• 1. Wie in 7 bis 10 dargestellt, kann die Aufnahmenut 12 der vorliegenden Erfindung den konvexen Zahnteil 41 des zahnradförmigen Werkstücks 40 oder den konvexen Teil 31 des sternförmigen Werkstücks 30 aufnehmen, kann die konkave Nut 13 den konvexen Zahnteil 41 des zahnradförmigen Werkstücks 40 oder den konvexen Teil 31 des sternförmigen Werkstücks 30 auch aufnehmen, sowie die drei konkaven Nuten 13 und die drei Aufnahmenuten 12 können zusammen eine Hälfte der gesamten Anzahl von den konvexen Zahnteilen 41 des zahnradförmigen Werkstücks 40 aufnehmen. So ist der erfindungsgemäße Schraubenschlüssel geeignet, an dem Werkstück in verschiedenen Formen aufzustecken.
• 2. Wie in 2, 8 und 9 dargestellt, weist die Klemmfläche 11 nach der vorliegenden Erfindung eine Breite H1 auf. Wenn die Breite H1 verändert ist und die Länge der Seite des Hexagons A nicht verändert ist, sind die Bogenlinie der Rutschfläche 112 und die Bogenlinie der beiden Flanken der Aufnahmenut 12 mit der Änderung der Breite H1 entsprechend verändert, so dass der von der Rutschfläche 112 und der Aufnahmenut 12 definierte Raum vergrößert oder verkleinert ist, und der Raum dem Toleranzbereich für Drehbewegung entspricht, wenn der konvexe Teil 31 des sternförmigen Werkstücks 30 aufgenommen ist, und der Raum auch dem Toleranzbereich für eine Drehbewegung entspricht, wenn ein hexagonales Werkstück 20 mit einem metrischen Maß oder ein zahnradförmiges Werkstück 40 im Zusammenwirken der Klemmflächen 11 mit der konkaven Nut 13 aufgenommen ist.
• 3. Wie in 2, 8 und 9 dargestellt, ist eine konkave Nut 13 auf der Klemmfläche 11 angeordnet. Die konkave Nut 13 umfasst zwei in Abstand und parallel zueinander angeordnete Flanken 131. Daher, wenn der Abstand zwischen den beiden Flanken 131 verändert ist, kann die konkave Nut 13 den konvexen Teil 31 des sternförmigen Werkstücks 30 entsprechend dem Toleranzbereich für eine Drehbewegung aufnehmen. Wenn die konkave Nut 13 verändert ist, sollte die Aufnahmenut 12 nicht verändert werden, so dass die Aufnahmenut 12 dem Toleranzbereich für eine Drehbewegung des zahnradförmigen Werkstücks 40 entspricht.

The present invention has the following advantages:

• 1. As in 7 to 10 shown, the receiving groove 12 the present invention, the convex tooth part 41 of the gear-shaped workpiece 40 or the convex part 31 of the star-shaped workpiece 30 can accommodate the concave groove 13 the convex tooth part 41 of the gear-shaped workpiece 40 or the convex part 31 of the star-shaped workpiece 30 also record, as well as the three concave grooves 13 and the three recording grooves 12 can together make up one half of the total number of convex teeth parts 41 of the gear-shaped workpiece 40 take up. Thus, the wrench according to the invention is suitable aufzustecken on the workpiece in various forms.
• 2. As in 2 . 8th and 9 shown, the clamping surface 11 according to the present invention, a width H1. If the width H1 is changed and the length of the side of the hexagon A is not changed, the arc line of the slip surface is 112 and the arc line of the two flanks of the receiving groove 12 With the change of the width H1 changed accordingly, so that of the sliding surface 112 and the receiving groove 12 defined space enlarged or reduced is, and the space corresponds to the tolerance range for rotational movement when the convex part 31 of the star-shaped workpiece 30 is included, and the space also corresponds to the tolerance range for a rotary motion when a hexagonal workpiece 20 with a metric dimension or a gear-shaped workpiece 40 in cooperation of the clamping surfaces 11 with the concave groove 13 is included.
• 3. As in 2 . 8th and 9 is a concave groove 13 on the clamping surface 11 arranged. The concave groove 13 comprises two spaced and parallel flanks 131 , Therefore, if the distance between the two flanks 131 changed, the concave groove 13 the convex part 31 of the star-shaped workpiece 30 record according to the tolerance range for a rotary movement. When the concave groove 13 is changed, the receiving groove should 12 not be changed, so that the receiving groove 12 the tolerance range for a rotational movement of the gear-shaped workpiece 40 equivalent.

Since the present invention has the above three advantages, the present invention is suitable for many workpieces of various dimensions. In addition, the hexagonal workpiece can 20 with metric dimension of 4 mm to 36 mm, the hexagonal workpiece 20 with English measure, the star-shaped workpiece 30 with a dimension according to DIN, E and the gear-shaped workpiece 40 with a measure according to DIN, E grouped in a group. Therefore, according to the tolerance range for a rotary motion, the present invention is suitable for more than 97% of all workpieces.

4. As in 3 to 7 are shown, only seven clamping parts 110 . 111 . 114 arranged in the plug-in opening according to the present invention. When the drive head 100 opposite the hexagonal workpiece 20 is rotated at an angle and it is necessary to perform a return movement, it is not necessary, the drive head 100 in the axial direction of the workpiece to be driven, and it is only necessary, the drive head 100 opposite the workpiece to be driven 20 to rotate and move sideways so that the workpiece to be driven 20 from the clamp in the plug-in opening 19 is free. When the drive head 100 is moved in reverse at the desired angle, and when the drive head 100 by means of the plug-in opening again on the workpiece to be driven 20 is attached, it is then possible, the workpiece 20 by means of the drive head 100 continue to drive to rotate, without freeing the workpiece from the Aufsteckung and then attach the drive head to the workpiece again.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 9838009 [0002, 0002]
• - US 7107879 [0003, 0003, 0003]
• - TW 269141 [0003, 0003, 0003]

Cited non-patent literature

• - DIN, 19 [0002]
• - DIN, E24 [0002]
• - DIN, 18 [0002]
• - DIN, E22 [0002]

Claims (10)

Wrench comprising a handle ( 10 ), which has an opposite first and a second end, at which first end a drive head ( 100 ), which drive head ( 100 ) a through opening ( 14 ) and by means of the through opening ( 14 ) on a workpiece to be driven ( 20 ; 30 ; 40 ; 50 ) is attachable, characterized in that the through opening ( 14 ) comprises: - a circular-shaped receiving opening ( 18 ), in which the workpiece to be driven ( 20 ; 30 ; 40 ; 50 ) is rotatably received; and - an attachment opening ( 19 ), the receiving opening ( 18 ) and with the receiving opening ( 18 ), wherein three clamping surfaces ( 11 ) and three grooves ( 12 ) on the inner peripheral wall of the plug-in opening ( 19 ) are arranged alternately about their central longitudinal axis, extending in the longitudinal direction extension of the clamping surfaces ( 11 ) and the grooves ( 12 ) is arranged parallel to the central longitudinal axis, the clamping surface ( 11 ) are arranged on an arcuate surface whose center region gradually projects in the direction of the central longitudinal axis, the receiving groove (FIG. 12 ) two symmetrical and arcuate flanks ( 120 ), and that of the receiving groove ( 12 ) defined space is sufficient, a convex part ( 31 ) of a star-shaped workpiece ( 30 ); each a concave groove ( 13 ) in the middle region of each clamping surface ( 11 ), the shape of the concave groove ( 13 ) other than the shape of the receiving groove ( 12 ) is formed, the longitudinal extent of the concave groove ( 13 ) is arranged parallel to the central longitudinal axis, each clamping surface ( 11 ) through the one concave groove ( 13 ) in a first clamping part ( 110 ) and a second clamping part ( 111 ) is formed divided, which first clamping part ( 110 ) and second clamping part ( 111 ) symmetrical to each other with respect to the center of the concave groove ( 13 ) are arranged, an inner edge of the lying in the last position receiving groove ( 12 ) with the second clamping part ( 111 ), the inner flank opposite the outer edge with a third clamping part ( 114 ) whose shape corresponds to the shape of the first clamping part ( 110 ), the concave groove ( 13 ) two opposite flanks ( 131 ) and one with the two flanks ( 131 ) concave bottom surface ( 132 ), the opening width of the concave groove ( 13 ) between the two flanks ( 131 ) for receiving a convex part ( 31 ) of the star-shaped workpiece ( 30 ) is formed, an arcuate guide surface ( 113 ) in the region of the connection of each clamping part ( 110 . 111 ) with the flank ( 131 ) of the concave groove ( 13 ) is formed, and the clamping part ( 110 . 111 ) with the receiving groove ( 12 ) over a sliding surface ( 121 ) is connected in a gently inclined manner, the sliding surface ( 121 ) and the receiving groove ( 12 ) define a space in which a convex part ( 31 ) of the star-shaped workpiece ( 30 ) is receivable, each group of the opposing first and second clamping part ( 110 . 111 ) has a common tangent, three common tangents on three sides of a hexagon (A) are arranged, the center (C) of a of the sides of the hexagon (A) tangent circle from the center (D) of the receiving opening ( 18 ) at a distance, the farthest distance (H3) from the third clamping part ( 114 ) to the wall of the receiving opening ( 18 ) is greater than the length of the largest diagonal of the hexagon (A). Wrench comprising a handle ( 10 ) having an opposite first end and a second end, at which first end a drive head ( 100 ) and a plug-in opening ( 19 ) are arranged, characterized in that the plug-in opening ( 19 ) on the drive head ( 100 ) arranged in C-shape, and for attachment to a workpiece ( 20 ; 30 ; 40 ; 50 ), three clamping surfaces ( 11 ) and three grooves ( 12 ) on the inner peripheral wall of the plug-in opening ( 19 ) distributed around its central longitudinal axis are arranged alternately, extending in the longitudinal direction extension of the clamping surfaces ( 11 ) and the grooves ( 12 ) is arranged parallel to the central longitudinal axis, the clamping surface ( 11 ) is arranged on an arcuate surface, the middle region is formed in the direction of the central longitudinal axis gradually projecting, the receiving groove ( 12 ) two symmetrical and arcuate flanks ( 120 ), and that of the receiving groove ( 12 ) defined space is sufficient, a convex part ( 31 ) of a star-shaped workpiece ( 30 ); each a concave groove ( 13 ) in the middle region of each clamping surface ( 11 ), the shape of the concave groove ( 13 ) other than the shape of the receiving groove ( 12 ) is formed, the longitudinal extent of the concave groove ( 13 ) is arranged parallel to the central longitudinal axis, each clamping surface ( 11 ) through the one concave groove ( 13 ) in a first clamping part ( 110 ) and a second clamping part ( 111 ) is formed divided, which first clamping part ( 110 ) and second clamping part ( 111 ) symmetrical to each other with respect to the center of the concave groove ( 13 ) are arranged, an inner edge of the lying in the last position receiving groove ( 12 ) with the second clamping part ( 111 ), an inner flank opposite outer edge with a third clamping part ( 114 ) whose shape corresponds to the shape of the first clamping part ( 110 ), the concave groove ( 13 ) two spaced apart and opposite flanks ( 131 ) and one with the two flanks ( 131 ) concave bottom surface ( 132 ), the opening width of the concave groove ( 13 ) between the two flanks ( 131 ) for receiving a convex part ( 31 ) of sternförmi workpiece ( 30 ) is formed, an arcuate guide surface ( 113 ) in the region of the connection of each clamping part ( 110 . 111 ) with the flank ( 131 ) of the concave groove ( 13 ) is formed, and the clamping part ( 110 . 111 ) with the receiving groove ( 12 ) over a sliding surface ( 121 ) is connected in a gently inclined manner, the sliding surface ( 121 ) and the receiving groove ( 12 ) define a space in which a convex part ( 31 ) of the star-shaped workpiece ( 30 ) is receivable, each group of the opposing first and second clamping part ( 110 . 111 ) has a common tangent and three common tangents lie on three sides of a hexagon (A). Wrench according to claim 1 or 2, wherein the receiving groove ( 12 ) a convex tooth part ( 41 ) of a gear-shaped workpiece ( 40 ). Wrench according to claim 1 or 2, wherein the two flanks ( 131 ) of the concave grooves ( 13 ) are arranged parallel to each other, the opening width of the concave groove ( 13 ) between the two flanks ( 131 ), a convex tooth part ( 41 ) of a gear-shaped workpiece ( 40 ). Wrench according to claim 1 or 2, wherein the concave bottom surface ( 132 ) of the concave grooves ( 13 ) is formed as a concave arc surface. A wrench according to claim 1 or 2, wherein a rounded angle in the location of the connection between the flanks (Fig. 131 ) of the concave groove ( 13 ) and the concave bottom surface ( 132 ) is provided. Wrench according to claim 1 or 2, wherein the receiving groove ( 12 ) over a sliding surface ( 112 ) with the clamping part ( 110 . 111 ), the sliding surface ( 112 ) the clamping part ( 110 ) in the connecting parts, and the sliding surface ( 112 ) the receiving groove ( 12 ) is not affected in the connection point. Wrench according to claim 1 or 2, wherein the sliding surface ( 112 ) and the receiving groove ( 12 ) define a space for receiving a convex tooth part ( 41 ) of a tooth-shaped workpiece ( 40 ) is trained. Wrench according to claim 1 or 2, wherein a limiting part ( 15 ) at a longitudinal end of the receiving groove ( 12 ) is arranged so that the receiving groove ( 12 ) is closed at this end. Wrench according to claim 1, wherein the receiving opening ( 18 ) on a side wall an interruption ( 17 ), so that the through opening ( 14 ) is formed in C-shape.