Quick Clamping Device for a Portable Machine Tool, in Particular an Angle Grinder, Comprising at Least One Output Shaft That Can Be Rotatably Driven

Abstract

A quick clamping device for a portable machine tool, in particular an angle grinder, includes at least one output shaft, at least one clamping unit, at least one operating unit, and at least one securing unit. The clamping unit, for the purpose of fixing an insert bit to the output shaft without using tools, includes at least one clamping element for applying a clamping force to the bit in a clamping position. The operating unit moves the clamping element into the clamping position and/or into a release position in which the insert bit can be removed from the clamping unit and/or the output shaft. The securing unit is designed to prevent movement of the clamping element from the clamping position into the release position at least under the action of a force decoupled from the operating unit and acting on the clamping element in the direction of the release position.

Claims

1. A quick clamping device for a portable power tool, comprising: at least one output shaft configured to be driven in rotation; at least one clamping unit including at least one movably mounted clamping element configured to exert a clamping force on an insert tool unit in a clamping position of the at least one movably mounted clamping element, the at least one clamping unit configured for fixing the insert tool unit to the at least one output shaft without use of tools; at least one operator control unit configured to move the at least one movably mounted clamping element into the clamping position and/or into a release position of the at least one movably mounted clamping element; and at least one securing unit configured to prevent movement of the at least one movably mounted clamping element from the clamping position into the release position of the at least one movably mounted clamping element at least when the at least one movably mounted clamping element is acted on by a first force which is decoupled from the at least one operator control unit and which acts in a first direction toward the release position of the at least one movably mounted clamping element, wherein, in the release position, the insert tool unit is configured to be removed from the at least one clamping unit and/or from the at least one output shaft.

2. The quick clamping device as claimed in claim 1, wherein: the at least one securing unit includes at least one movably mounted positive locking and/or non-positive locking element; and at least in the clamping position of the at least one movably mounted clamping element, the at least one movably mounted positive locking and/or non-positive locking element engages at least partially into at least one of the at least one movably mounted clamping element and a transmission element, which interacts with the clamping element in order to secure the at least one movably mounted clamping element against movement into the release position of the at least one movably mounted clamping element.

3. The quick clamping device as claimed in claim 1, wherein: the at least one securing unit includes at least one movably mounted positive locking and/or non-positive locking element; at least in the clamping position of the at least one movably mounted clamping element, the at least one movably mounted positive locking and/or non-positive locking element bears against the at least one movably mounted clamping element in such a way that the at least one movably mounted positive locking and/or non-positive locking element exerts a main securing force on the at least one movably mounted clamping element along a second direction running at least substantially parallel or at least substantially perpendicular to a clamping axis of the at least one clamping unit; and the main securing force counteracts movement of the at least one movably mounted clamping element into the release position.

4. The quick clamping device as claimed in claim 1, wherein: the at least one securing unit is at least partially integral with the at least one clamping unit; and the at least one securing unit includes at least one self-locking contour arranged on the at least one movably mounted clamping element.

5. The quick clamping device as claimed in claim 4, wherein: in the clamping position of the at least one movably mounted clamping element, the self-locking contour is oriented such that, when the at least one movably mounted clamping element is subjected to the first force which is decoupled from the at least one operator control unit and which acts in the first direction of the release position of the at least one movably mounted clamping element; and a main securing force running at least substantially perpendicular to the clamping axis of the at least one clamping unit is exerted on the at least one movably mounted clamping element at least via the self-locking contour.

6. The quick clamping device as claimed in claim 4, wherein, at least in the clamping position of the at least one movably mounted clamping element, the self-locking contour encloses an angle of less than 40° relative to the clamping axis of the at least one clamping unit.

7. The quick clamping device as claimed in claim 4, wherein: the self-locking contour includes at least one contact surface; in the clamping position of the at least one movably mounted clamping element, the at least one contact surface runs at least substantially parallel to the clamping axis of the at least one clamping unit.

8. The quick clamping device as claimed in claim 4, wherein: the at least one clamping unit includes a slotted-guide element having a clamping contour and a release contour; and the self-locking contour is arranged in a transition region between the clamping contour and the release contour.

9. The quick clamping device as claimed in claim 1, wherein: the at least one securing unit includes at least one spring element and at least one movably mounted positive locking and/or non-positive locking element; the at least one spring element acts on the at least one movably mounted positive locking and/or non-positive locking element with a spring force in a direction of the at least one movably mounted clamping element.

10. The quick clamping device as claimed in claim 9, wherein the at least one movably mounted positive locking and/or non-positive locking element is movable counter to the spring force of the at least one spring element via the at least one operator control unit.

11. The quick clamping device as claimed in claim 9, wherein: the at least one movably mounted clamping element includes at least one securing recess; and in the clamping position of the at least one movably mounted clamping element, the at least one movably mounted positive locking and/or non-positive locking element at least partially engages into the at least one securing recess.

12. The quick clamping device as claimed in claim 1, wherein: the at least one securing unit includes at least one positive locking and/or non-positive locking element movable via a centrifugal force into a securing position of the at least one positive locking and/or non-positive locking element; and in the securing position, the at least one movably mounted clamping element is substantially secured against movement from the clamping position into the release position of the at least one movably mounted clamping element.

13. The quick clamping device as claimed in claim 1, wherein the at least one securing unit includes at least one output element configured to output at least a functional state of the at least one securing unit to an operator.

14. A portable power tool, comprising: a quick clamping device including: at least one output shaft configured to be driven in rotation; at least one clamping unit including at least one movably mounted clamping element configured to exert a clamping force on an insert tool unit in a clamping position of the at least one movably mounted clamping element, the at least one clamping unit configured to fix the insert tool unit to the at least one output shaft without use of tools; at least one operator control unit configured to move the at least one movably mounted clamping element into the clamping position and/or into a release position of the at least one movably mounted clamping element; and at least one securing unit configured to prevent movement of the at least one movably mounted clamping element from the clamping position into the release position of the at least one movably mounted clamping element at least when the at least one movably mounted clamping element is acted on by a first force which is decoupled from the at least one operator control unit and which acts in a first direction toward the release position of the at least one movably mounted clamping element, wherein, in the release position, the insert tool unit is configured to be removed from the at least one clamping unit and/or from the at least one output shaft.

15. The quick clamping device of claim 1, wherein the portable power tool is an angle grinder.

16. The quick clamping device of claim 1, wherein the at least one securing unit is at least one of a self-locking unit and a detent unit.

17. The quick clamping device of claim 14, wherein the portable power tool is an angle grinder.

Description

DRAWING

[0024] Further advantages will emerge from the following description of the drawing. The drawing illustrates exemplary embodiments of the invention. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine to form meaningful further combinations.

[0025] In the drawing:

[0026] FIG. 1 shows a portable power tool according to the invention having a quick clamping device according to the invention in a schematic illustration,

[0027] FIG. 2 shows a sectional view of the portable power tool according to the invention and of the quick clamping device according to the invention in a schematic illustration,

[0028] FIG. 3 shows a detail view of a securing unit of the quick clamping device according to the invention in a schematic illustration, and

[0029] FIG. 4 shows a sectional view of an alternative portable power tool according to the invention and of an alternative quick clamping device according to the invention having an alternative securing unit in a schematic illustration.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0030] FIG. 1 shows a portable power tool 14a which is designed as an angle grinder and which has a quick clamping device 10a. It is however also conceivable for the portable power tool 14a to be of some other design that appears expedient to a person skilled in the art, for example designed as a circular saw, as a grinder or the like. The portable power tool 14a comprises a gearing housing 62a for accommodating and/or for the mounting of a gearing unit 64a of the portable power tool 14a. The gearing housing 62a is preferably formed from a metallic material. It is however also conceivable for the gearing housing 62a to be formed from some other material that appears expedient to a person skilled in the art, for example from plastic or the like. The gearing unit 64a is preferably designed as an angle gearing. The gearing unit 64a comprises in particular an output shaft 12a which can be driven in rotation and to which an insert tool unit 18a can be fixed, in particular by means of the quick clamping device 10a. The output shaft 12a is preferably designed as a hollow spindle, in which the quick clamping device 10a is at least partially arranged (FIG. 2). A protective cover unit (not illustrated in any more detail here) can be arranged, in a manner already known to a person skilled in the art, on the gearing housing 62a. An auxiliary handle (not illustrated in any more detail here) can be arranged, in a manner already known to a person skilled in the art, on the gearing housing 62a. The portable power tool 14a comprises a motor housing 66a for accommodating and/or for the mounting of a drive unit 68a of the portable power tool 14a. The drive unit 68a is preferably provided, in a manner already known to a person skilled in the art, for driving the output shaft 12a in rotation about an axis of rotation 70a of the output shaft 12a by interaction with the gearing unit 64a. The axis of rotation 70a of the output shaft 12a runs at least substantially perpendicular to a drive axis 96a of the drive unit 68a. The drive unit 68a is preferably designed as an electric motor unit. It is however also conceivable for the drive unit 68a to be of some other design that appears expedient to a person skilled in the art, for example designed as a combustion-type drive unit, as a hybrid drive unit, as a pneumatic drive unit or the like.

[0031] FIG. 2 shows a sectional view of the portable power tool 14a, in particular in the region of the gearing housing 62a, and of the quick clamping device 10a. The quick clamping device 10a for the portable power tool 14a, which has at least the output shaft 12a that can be driven in rotation, comprises at least one clamping unit 16a, which, for tool-free fixing of the insert tool unit 18a to the output shaft 12a, has at least one movably mounted clamping element 20a, 22a for the action of a clamping force on the insert tool unit 18a in a clamping position of the clamping element 20a, 22a. Furthermore, the quick clamping device 10a comprises at least one operator control unit 24a for moving the clamping element 20a, 22a into the clamping position and/or into a release position of the clamping element 20a, 22a, in which the insert tool unit 18a is removable from the clamping unit 16a and/or from the output shaft 12a. The clamping unit 16a comprises at least two movably mounted clamping elements 20a, 22a. It is however also conceivable for the clamping unit 16a to comprise a number of clamping elements 20a, 22a other than two. The at least two clamping elements 20a, 22a have an at least substantially analogous design, such that features disclosed with regard to one of the clamping elements 20a, 22a are to be regarded as likewise disclosed for the further clamping element 20a, 22a. The at least two clamping elements 20a, 22a are pivotably mounted. A pivot axis 72a of the at least two clamping elements 20a, 22a runs at least substantially perpendicular to the axis of rotation 70a of the output shaft 12a. The at least two clamping elements 20a, 22a are provided for fixing the insert tool unit 18a, in a state in which it is arranged on the clamping unit 16a and/or the output shaft 12a, axially on the output shaft 12a, in particular in the clamping position of the at least two clamping elements 20a, 22a. The at least two clamping elements 20a, 22a are connected rotationally conjointly to the output shaft 12a. The at least two clamping elements 20a, 22a can be driven in rotation about the axis of rotation 70a together with the output shaft 12a.

[0032] The clamping unit 16a comprises, for a transmission of torque to the insert tool unit 18a, at least one rotary driving element 74a. In a state of the insert tool unit 18a in which it is arranged on the clamping unit 16a and/or the output shaft 12a, the rotary driving element 74a engages into a receiving recess (not illustrated in any more detail here) of the insert tool unit 18a and, for a transmission of torque, bears against at least one edge, which delimits the receiving recess, of the insert tool unit 18a. A transmission of torque between the output shaft 12a and the insert tool unit 18a arranged on the clamping unit 16a and/or the output shaft 12a is preferably realized, in a manner already known to a person skilled in the art, by means of a positive locking connection between the rotary driving element 74a and the insert tool unit 18a. The rotary driving element 74a is arranged rotationally conjointly on the output shaft 12a. The rotary driving element 74a can be driven in rotation about the axis of rotation 70a together with the output shaft 12a.

[0033] The operator control unit 24a is preferably provided for moving the clamping element 20a, 22a, in particular the at least two clamping elements 20a, 22a, at least into the release position, in which the insert tool unit 18a is removable from the clamping unit 16a and/or from the output shaft 12a. Alternatively or in addition, it is conceivable for the operator control unit 24a to be provided for moving the clamping element 20a, 22a, in particular the at least two clamping elements 20a, 22a, at least into the clamping position, in which the insert tool unit 18a is fixable by means of the clamping unit 16a to the output shaft 12a. The operator control unit 24a preferably comprises at least one operator control element 76a, which is actuatable by an operator. The operator control element 76a is designed as an operator control lever. The operator control element 76a comprises a movement axis 78a, in particular a pivot axis, which runs transversely, in particular at least substantially perpendicularly, with respect to the axis of rotation 70a of the output shaft 12a. The operator control element 76a is preferably mounted so as to be pivotable about the movement axis 78a, in particular pivot axis. The operator control element 76a is decoupled from a rotational movement of the output shaft 12a. The operator control element 76a comprises an eccentric portion 80a for an actuation of the actuating element 82a of the operator control unit 24a. The actuating element 82a is mounted so as to be movable in translational fashion along the axis of rotation 70a, in particular in the output shaft 12a and/or in the gearing housing 62a. The actuating element 82a is fixed in the gearing housing 62a so as to be prevented from rotating relative to the gearing housing 62a, in particular owing to at least one lateral flattened portion of the actuating element 82a, which permits an axial movement and prevents a rotational movement. In the region of the actuating element 82a, there is preferably arranged a seal element 84a, for example a rubber seal or the like, in particular for at least substantially preventing an ingress of dirt into the gearing housing 62a and/or into the clamping unit 16a.

[0034] The operator control unit 24a comprises at least one decoupling element 86a which can be placed in contact with the actuating element 82a or is in contact with the actuating element 82a. The decoupling element 86a is preferably mounted, in particular in the output shaft 12a or in a transmission element 36a of the clamping unit 16a, so as to be movable in translational fashion along the axis of rotation 70a. The decoupling element 86a comprises in particular a conical connection region which engages at least partially into a recess of the actuating element 82a. A friction action between the actuating element 82a and the decoupling element 86a is in particular dependent on a design of the conical connecting region and on a spring force of a decoupling spring element 90a of the operator control unit 24a. The decoupling spring element 90a is provided for acting on the decoupling element 86a with a spring force in the direction of the actuating element 82a. The decoupling spring element 90a is arranged in the transmission element 36a of the clamping unit 16a. The transmission element 36a is designed as a clamping fork. The transmission element 36a is connected rotationally conjointly to the output element 12a. The transmission element 36a is movable in translational fashion along a clamping axis 40a of the clamping unit 16a. The transmission element 36a is mounted movably in the output shaft 12a. The transmission element 36a can, at least by means of a clamping spring element 88a of the clamping unit 16a, be acted on with a spring force along the clamping axis 40a, in particular in the direction of the operator control unit 24a.

[0035] The operator control unit 24a has at least one connecting element 92a which is provided for connecting the decoupling element 86a and the transmission element 36a to one another in terms of movement, in particular at least in a state of the output shaft 12a at a low rotational speed or when the output shaft 12a is at a standstill. The connecting element 92a is designed as a bolt. The connecting element 92a is fixed to the decoupling element 86a. The connecting element 92a is movable together with the decoupling element 86a. The connecting element 92a extends into a guide slot (not illustrated in any more detail here) of the transmission element 36a. During a rotational movement of the output shaft 12a, the decoupling element 86a and the connecting element 92a are rotatable relative to the transmission element 36a owing to a braking action resulting from an actuation of the actuating element 82a, wherein the connecting element 92a is movable in the guide slot such that the decoupling element 86a is movable counter to a spring force of the decoupling spring element 90a into a guide recess 94a of the transmission element 36a. An actuation of the operator control element 76a during a rotational movement of the output shaft 12a can be converted into a movement of the actuating element 82a and of the decoupling element 86a relative to the transmission element 36a. A movement of the transmission element 36a resulting from an action of an operator control force by means of the operator control unit 24a for the purposes of transferring the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, from the clamping position into the release position can be substantially prevented during a rotational movement of the output shaft 12a. When the output shaft 12a is at a low rotational speed or when the output shaft 12a is at a standstill, an axial force exerted by the actuating element 82a on the decoupling element 86a can be transmitted to the transmission element 36a by means of an interaction of the connecting element 92a and the guide slot. The transmission element 36a is movable by means of the operator control unit 24a counter to a spring force of the clamping spring element 88a. The transmission element 36a is provided for moving the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, from the clamping position into the release position.

[0036] The clamping element 20a, 22a, in particular the clamping elements 20a, 22a, is/are mounted movably, in particular pivotably, on the output shaft 12a, in particular in the output shaft 12a. The pivot axis 72a of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, runs preferably at least substantially perpendicular to the clamping axis 40a of the clamping unit 16a. The clamping element 20a, 22a, in particular the clamping elements 20a, 22a, has/have at least one slotted-guide element 50a which is provided for interacting with a slotted-guide engagement element. The slotted-guide engagement element is fixed to the transmission element 36a. Owing to an interaction of the slotted-guide engagement element and of the slotted-guide element 50a, the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, is/are movable from the clamping position into the release position or from the release position into the clamping position. The clamping element 20a, 22a, in particular the clamping elements 20a, 22a, is/are in particular movable from the release position into the clamping position by means of an action of a spring force of the clamping spring element 88a on the transmission element 36a. The clamping element 20a, 22a, in particular the clamping elements 20a, 22a, is/are movable into the clamping position automatically, in particular after withdrawal of an action of a force exerted by an operator by means of the operator control unit 24a, owing to an action of a spring force of the clamping spring element 88a.

[0037] The quick clamping device 10a comprises at least one securing unit 26a, in particular a self-locking unit and/or a detent unit, which is provided for preventing a movement of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, from the clamping position into the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, at least in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being acted on by a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a. The securing unit 26a has at least one movably mounted positive locking and/or non-positive locking element 28a, 30a, 32a, 34a which, at least in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, engages at least partially into the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, and/or into the transmission element 36a, which interacts with the clamping element 20a, 22a, in particular with the clamping elements 20a, 22a, of the clamping unit 16a, in order to secure the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, against a movement into the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a. The positive locking and/or non-positive locking element 28a is formed as the slotted-guide engagement element (cf. FIGS. 2 and 3). The positive locking and/or non-positive locking element 28a is designed as a bolt which is fixed to the transmission element 36a, in particular between two fork ends of the transmission element 36a. Alternatively or in addition, the securing unit 26a comprises at least one further positive locking and/or non-positive locking element 30a, 32a, which is designed as a detent element and which is provided for engaging into the clamping element 20a, 22a, in particular in the clamping position of the clamping element 20a, 22a. The securing unit 26a preferably alternatively or additionally comprises at least two further positive locking and/or non-positive locking elements 30a, 32a designed as detent elements, wherein in each case one engages into one of the clamping elements 20a, 22a, in particular in the clamping position of the clamping elements 20a, 22a. The further positive locking and/or non-positive locking elements 30a, 32a are designed as movably mounted detent elements. The further positive locking and/or non-positive locking elements 30a, 32a are movable, in particular movable in translational fashion, along a direction running at least substantially perpendicular to the axis of rotation 70a and/or to the clamping axis 40a. The axis of rotation 70a and the clamping axis 40a preferably run at least substantially parallel, in particular, axially, with respect to one another. The securing unit 26a preferably alternatively or additionally comprises an additional positive locking and/or non-positive locking element 34a, which is provided for engaging into the transmission element 36a, in particular in a clamping position of the clamping elements 20a, 22a and/or in an end position, moved by means of a spring force of the clamping spring element 88a, of the transmission element 36a. The additional positive locking and/or non-positive locking element 34a is designed as a movably mounted detent element. The additional positive locking and/or non-positive locking element 34a is mounted so as to be movable, in particular movable in translational fashion, along a direction running at least substantially perpendicular to the axis of rotation 70a and/or to the clamping axis 40a.

[0038] The securing unit 26a has at least the movably mounted positive locking and/or non-positive locking element 28a, 30a, 32a, in particular the positive locking and/or non-positive locking element 28a designed as a slotted-guide engagement element and/or the further positive locking and/or non-positive locking elements 28a designed as detent elements, which, at least in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, bear(s) against the clamping element 20a, 22a, in particular against the clamping elements 20a, 22a, such that a main securing force 38a (cf. FIG. 3) can be exerted on the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, along a direction running at least substantially parallel or at least substantially perpendicular to the clamping axis 40a of the clamping unit 16a, which main securing force counteracts a movement of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, into the release position. The main securing force 38a preferably acts such that no force components or only small force components act along the clamping axis 40a on the transmission element 36a. It can advantageously be achieved that the slotted-guide engagement element cannot move into a release contour 48a of the slotted-guide element 50a, in particular of the slotted-guide track. The securing unit 26a comprises at least one spring element 52a, 54a, which acts on at least one of the movably mounted further positive locking and/or non-positive locking elements 30a, 32a of the securing unit 26a with a spring force in the direction of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a. It is preferable for in each case one of two spring elements 52a, 54a of the securing unit 26a to be assigned to in each case one of the further positive locking and/or non-positive locking elements 30a, 32a. It is conceivable for the securing unit 26a to comprise at least one additional spring element (not illustrated in any more detail here) which acts on the movably mounted additional positive locking and/or non-positive locking element 34a of the securing unit 26a with a spring force in the direction of the transmission element 36a. The clamping element 20a, 22a, in particular the clamping elements 20a, 22a, comprise(s) at least one securing recess 56a, 58a, into which the further positive locking and/or non-positive locking element 30a, 32a at least partially engages in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a.

[0039] The positive locking and/or non-positive locking element 30a, 32a, 34a, in particular the further positive locking and/or non-positive locking elements 30a, 32a and the additional positive locking and/or non-positive locking element 34a, are/is movable counter to a spring force of the spring element 52a, 54a by means of the operator control unit 24a. The operator control unit 24a may comprise a force conversion element which moves the positive locking and/or non-positive locking element 30a, 32a, 34a, in particular the further positive locking and/or non-positive locking elements 30a, 32a and the additional positive locking and/or non-positive locking element 34a, out of an engagement position in a manner dependent on a movement of the operator control element 76a and/or of the actuating element 82a in the direction of the clamping unit 16a. The operator control unit 24a may alternatively have an electronic monitoring unit which monitors a movement of the operator control element 76a and/or of the actuating element 82a, wherein, in the event of a movement of the operator control element 76a and/or of the actuating element 82a being detected, the positive locking and/or non-positive locking element 30a, 32a, 34a, in particular the further positive locking and/or non-positive locking elements 30a, 32a and the additional positive locking and/or non-positive locking element 34a, are/is movable out of an engagement position by means of an electric actuator. Further embodiments of the operator control unit 24a that appear expedient to a person skilled in the art for a movement of the positive locking and/or non-positive locking element 30a, 32a, 34a, in particular of the further positive locking and/or non-positive locking elements 30a, 32a and of the additional positive locking and/or non-positive locking element 34a, are likewise conceivable.

[0040] The securing unit 26a is formed at least partially integrally with the clamping unit 16a, wherein the securing unit 26a has at least one self-locking contour 42a arranged on the clamping element 20a, 22a. The securing unit 26a referee comprises at least two self-locking contours 42a, wherein one of the at least two self-locking contours 42a is arranged in each case on one of the clamping elements 20a, 22a (only one of the two self-locking contours 42a is illustrated in FIG. 3). The self-locking contour 42a is formed integrally with the slotted-guide element 50a. In particular, the self-locking contour 42a forms an edge of the slotted-guide element 50a which delimits the slotted-guide element 50a. The slotted-guide element 50a is designed preferably as a slotted-guide track, which is provided for moving the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, into the clamping position and/or into the release position by means of an interaction with the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element. The self-locking contour 42a is arranged in a transition region between a clamping contour 46a and a release contour 48a of the slotted-guide element 50a of the clamping unit 16a. The clamping contour 46a is provided for moving the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, into the clamping position by means of an interaction with the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element. The release contour 48a is provided for moving the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, into the release position by means of an interaction with the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element.

[0041] In a clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, the self-locking contour 42a is oriented such that, in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being acted on with a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, a main securing force 38a can be exerted on the clamping element 20a, 22a, in particular on the clamping elements 20a, 22a, at least by means of the self-locking contour 42a, which main securing force runs at least substantially perpendicular to a clamping axis 40a of the clamping unit 16a. The main securing force 38a preferably acts such that no force components or only small force components act along the clamping axis 40a on the transmission element 36a. It can advantageously be achieved that the slotted-guide engagement element cannot move into a release contour 48a of the slotted-guide element 50a, in particular of the slotted-guide track. Preferably, by means of the interaction of the self-locking contour 42a with the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element, in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being subjected to a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, a main securing force 38a can be exerted on the clamping element 20a, 22a, in particular on the clamping elements 20a, 22a. Preferably, by means of an interaction of the self-locking contour 42a with the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element, in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being subjected to a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, a movement capability of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, into the release position can be substantially blocked. At least in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, the self-locking contour 42a encloses an angle of less than 40° with the clamping axis 40a of the clamping unit 16a. It is conceivable that, in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, the self-locking contour 42a, in particular a contact surface 44a of the self-locking contour 42a, is oriented in the direction of the operator control unit 24a or in the direction of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, in particular so as to enclose an angle of less than 40° with the clamping axis 40a of the clamping unit 16a. The self-locking contour 42a has at least the contact surface 44a, which in the clamping position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, runs at least substantially parallel to the clamping axis 40a of the clamping unit 16a. By means of an interaction of the contact surface 44a of the self-locking contour 42a and the positive locking and/or non-positive locking element 28a designed as slotted-guide engagement element, in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being subjected to a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, a main securing force 38a can be exerted on the clamping element 20a, 22a, in particular on the clamping elements 20a, 22a. It is advantageously possible to realize a self-locking function of the clamping unit 16a and/or of the securing unit 26a, in order the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, in the event of the clamping element 20a, 22a, in particular the clamping elements 20a, 22a, being subjected to a force which is decoupled from the operator control unit 24a and which acts in the direction of the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, to ensure a movement of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a, from the clamping position into the release position of the clamping element 20a, 22a, in particular of the clamping elements 20a, 22a.

[0042] The securing unit 26a has at least one output element 60a which is provided for outputting at least a functional state of the securing unit 26a to an operator. The output element 60a may be designed as a mechanical element, as an electronic element or as an electrical element. The output element 60a is preferably provided for outputting a functional state of the securing unit 26a by haptic, acoustic and/or optical means. The functional state of the securing unit 26a preferably describes a state of the securing unit 26a such as for example a securing of the clamping element 20a, 22a, a released state of the securing unit 26a, in which the clamping element 20a, 22a is not secured, a defect of the securing unit 26a or other states of the securing unit 26a that appear expedient to a person skilled in the art. The output element 60a may be designed as a display, as a single light source, such as for example an LED, as a mechanically movable display element, as a loudspeaker or the like.

[0043] FIG. 4 shows a further exemplary embodiment of the invention. The following descriptions and the drawings are restricted substantially to the differences between the exemplary embodiments, wherein, with regard to components of identical designation, in particular with regard to components with the same reference designations, reference may basically also be made to the drawings and/or the description of the other exemplary embodiments, in particular of FIGS. 1 to 3. To distinguish between the exemplary embodiments, the alphabetic character a has been added as a suffix to the reference designations of the exemplary embodiment in FIGS. 1 to 3. In the exemplary embodiments of FIG. 4, the alphabetic character a has been replaced by the alphabetic character b.

[0044] FIG. 4 shows a sectional view of an alternative portable power tool 14b and of an alternative quick clamping device 10b. The portable power tool 14b illustrated in FIG. 4 has an at least substantially analogous design in relation to the portable power tool 14a described in the description relating to FIGS. 1 to 3. The quick clamping device 10b for the portable power tool 14b, which has at least the output shaft 12b that can be driven in rotation, comprises at least one clamping unit 16b, which, for tool-free fixing of an insert tool unit (not illustrated in any more detail here) to the output shaft 12b, has at least one movably mounted clamping element 20b, 22b, in particular at least two movably mounted clamping elements 20b, 22b, for the action of a clamping force on the insert tool unit in a clamping position of the clamping element 20b, 22b.

[0045] Furthermore, the quick clamping device 10b comprises at least one operator control unit 24b for moving the clamping element 20b, 22b into the clamping position and/or into a release position of the clamping element 20b, 22b, in which the insert tool unit 18b is removable from the clamping unit 16b and/or from the output shaft 12b. The operator control unit 24b comprises at least one movably mounted operator control element (not illustrated in any more detail here) which is provided for acting on an actuating element 82b of the operator control unit 24b in order to move the clamping element 20b, 22b into the clamping position and/or into a release position. The actuating element 82b is connected rotationally conjointly to the output shaft 12b and is mounted so as to be movable in translational fashion in the output shaft 12b. It is however also conceivable for the actuating element 82b and/or the operator control unit 24b to be designed analogously to the actuating element 82a illustrated in FIGS. 1 to 3 and/or to the operator control unit 24a illustrated in FIGS. 1 to 3.

[0046] Furthermore, the quick clamping device 10b comprises at least one securing unit 26b, in particular a self-locking unit and/or a detent unit, which is provided for preventing a movement of the clamping element 20b, 22b from the clamping position into the release position of the clamping element 20b, 22b at least in the event of the clamping element 20b, 22b being subjected to a force which is decoupled from the operator control unit 24b and which acts in the direction of the release position of the clamping element 20b, 22b. The securing unit 26b has, in particular in addition to a self-locking contour (not illustrated in any more detail here), at least one positive locking and/or non-positive locking element 28b, 30b which, by means of a centrifugal force, in particular by means of a centrifugal force that can be caused owing to a rotation of the securing unit 26b and/or of the output shaft 12b about an axis of rotation 70b of the output shaft 12b, is movable into a securing position of the positive locking and/or non-positive locking element 28b, 30b, in which the clamping element 20b, 22b is substantially secured against a movement from the clamping position into the release position of the clamping element 20b, 22b. The securing unit 26b preferably comprises at least two positive locking and/or non-positive locking elements 28b, 30b which, by means of a centrifugal force, are movable into a securing position of the positive locking and/or non-positive locking elements 28b, 30b, in which the clamping element 20b, 22b is substantially secured against a movement from the clamping position into the release position of the clamping element 20b, 22b. The positive locking and/or non-positive locking elements 28b, 30b are mounted so as to be movable, in particular movable in translational fashion, along a direction running at least substantially perpendicular to the axis of rotation 70b of the output shaft 12b. The securing unit 26b comprises at least one spring element 52b, 54b which acts on at least one of the movably mounted positive locking and/or non-positive locking elements 28b, 30b of the securing unit 26b with a spring force in the direction of the clamping elements 20b, 22b. The securing unit 26b preferably comprises at least two spring elements 52b, 54b, wherein in each case one of the at least two spring elements 52b, 54b acts on in each case one of the positive locking and/or non-positive locking elements 28b, 30b with a spring force. The positive locking and/or non-positive locking elements 28b, 30b can be moved into a securing position counter to a spring force of the spring elements 52b, 54b by a centrifugal force. With regard to further features of the quick clamping device 10b illustrated in FIG. 4, reference may be made to the description of the quick clamping device 10a illustrated in FIGS. 1 to 3.