EP2632636B1 - Clamping device for a hand-held machine tool - Google Patents

Description

State of the art

There are already hand tool clamping devices known which comprise a clamping unit which is intended to clamp a tool on a spindle. Furthermore, the hand tool clamping devices comprise a flow safety unit for preventing the clamping unit and / or the tool from running out of the spindle (see, for example, US Pat DE 102 008 015 955 A1 )

Disclosure of the invention

The invention relates to a hand tool clamping device with at least one clamping unit, which is intended to clamp a tool on a spindle, and with at least one flow safety unit to prevent a running of the clamping unit and / or the tool from the spindle.

It is proposed a hand tool clamping device with the features of claim 1.

A "clamping unit" is to be understood here in particular as a unit which is intended to clamp the tool axially against the spindle against a receiving flange. Preferably, the clamping unit is screwed by means of a thread with the spindle. However, it is also conceivable that the clamping unit by means of another, a professional appear appropriate sense connection to a bracing of the tool with the Spindle is connected. In this context, "intended" should be understood to mean in particular specially equipped and / or specially designed. A "down-flow protection unit" is to be understood here as meaning, in particular, a unit which is intended to at least substantially prevent a release of a clamping force of the fastening unit in a braking operation in a braking operation and, in particular, to provide a clamping force acting on the tool by the clamping unit increase. In this case, a "movement change unit" should in particular define a unit which comprises a mechanism, in particular a thread or other mechanisms that appear meaningful to a person skilled in the art, by means of which a movement type, such as a rotation, for example, into another type of movement, such as translation, can be converted. A "braking operation" is to be understood here as meaning in particular an operation of a handheld power tool, in particular a spindle of the handheld power tool, in which the spindle is braked by means of a braking device, so that the spindle can run after, such as when a power supply to an electric motor is interrupted. can be advantageous at least largely prevented. In the braking operation may occur by moments of inertia of the tool, in particular the disc-shaped tool, to a relative movement between the tool mounted on the spindle, and provided for tightening the tool on the spindle clamping unit. The relative movement between the tool and the clamping unit can lead to a clamping force of the clamping unit is reduced and thus the clamping unit and / or the tool can run off of the spindle. By means of the hand tool clamping device according to the invention, such a running of the clamping unit from the spindle and thus a release of the tool from the spindle can be advantageously avoided.

Furthermore, it is proposed that the movement change unit is designed as a lifting unit, which is provided to generate at least a relative movement of the two clamping elements along an axial direction during braking operation. A "lifting unit" is to be understood here in particular as a unit by means of which a movement of an element, in particular a tensioning element of the tensioning unit, along a straight path, in particular along a rotation axis of the spindle, can be generated. In this case, an "axial direction" is to be understood to mean, in particular, a direction along a central axis of the Clamping unit are understood, around which the clamping unit is at least substantially rotationally symmetrical. By means of the embodiment according to the invention can advantageously be generated an axial stroke of the clamping elements.

In a preferred embodiment, the lifting unit has at least one lifting element, which is formed at least partially in one piece with one of the two clamping elements. By "one piece" should be understood in particular at least materially connected connected, for example, by a welding process, a gluing process, a Anspritzprozess and / or another, the skilled person appear useful process, and / or advantageously formed in one piece, such as by a Manufacture from a casting and / or by a production in a one- or multi-component injection molding process and advantageously from a single blank. Advantageously, installation space, assembly costs and costs can be saved.

It is also proposed that the lifting element is formed in a ramp shape. "Ramp-shaped" is to be understood here in particular as a geometric shape that has a mathematically defined gradient along a path starting from a starting point in the direction of an end point, so that there is a height difference between the starting point and the end point. Advantageously, the lifting unit has at least one further lifting element which generates the second relative movement as a result of the first relative movement by means of an interaction with the lifting element. A pitch of the lifting elements is preferably equal to or greater than a pitch of a thread of a clamping element of the clamping unit and the spindle to which the clamping unit is open and unscrewed. The pitch of the lifting elements corresponds in particular to 100 to 150% of the pitch of the thread of the clamping element and the spindle, preferably 110 to 140% of the pitch of the thread of the clamping element and the spindle and more preferably 120 to 130% of the pitch of the thread of the clamping element and the Spindle. To increase a friction within the thread of the fastening unit and the spindle compared to the friction between the lifting elements, it is conceivable that friction-increasing means are incorporated in the thread of the fastening unit and the spindle, such as rubber elements, spring elements, coatings, etc. In an alternative embodiment the flow control device according to the invention it is conceivable for generating an Axialhubs between the first transmission element and the second transmission element, that a lifting element of the lifting unit is designed as a rolling body, which rolls on a rotation of the first transmission element relative to the second transmission element along a ramp-shaped lifting element. It can be achieved structurally simple relative movement for generating and / or maintaining a clamping force during braking operation.

Preferably, the stop element is integrally formed with one of the clamping elements, wherein another of the clamping elements comprises at least one recess which is intended to receive the stop element. By means of the embodiment according to the invention can advantageously be an angular range over which the clamping elements are rotatable relative to each other, limited. The angle range here is in particular less than 25 °, preferably less than 15 ° and particularly preferably less than 7 °.

In an alternative embodiment of the hand tool clamping device according to the invention, the lifting unit is designed as a cam gear, which has at least one lifting element designed as a control recess into which at least one control element of the cam mechanism at least partially engages. A "cam mechanism" is to be understood here as meaning, in particular, a mechanism which actuates a component as a result of a movement of a first cam member, in particular a movement of the control member about an axis, and as a result of interaction with a second cam member, in particular the control cam performs predetermined movement by the interaction of the cam members. A "control recess" is to be understood here in particular as a material recess into which the control element engages in order to produce a movement, wherein the control element and the control recess are movable in particular relative to one another. By means of the flow control device according to the invention structurally simple guidance of the control can be achieved in the control recess. Furthermore, a drainage of the tool can advantageously be prevented.

Furthermore, it is proposed that the control is pin-shaped. The term "pin-shaped" should in particular be understood to mean a geometric shape which has at least essentially a main extension, in particular a main extension along a central axis about which the geometric shape is rotationally symmetrical, the main extension being at least as large as a perpendicular to the main extension Extension, in particular a diameter, the geometric shape. Particularly preferably, the control is formed by a cylindrical pin. However, it is also conceivable that the control element is embodied in another form that appears appropriate to a person skilled in the art. A main extension of the control element runs in an assembled state at least substantially perpendicular to a central axis of the clamping unit and / or to a rotational axis of the spindle. The term "substantially perpendicular" is intended here to define, in particular, an orientation of a direction relative to a reference direction, the direction and the reference direction, in particular in one plane, including an angle of 90 ° and the angle a maximum deviation of, in particular, less than 8 °, advantageously less than 5 ° and particularly advantageously less than 2 °.

However, it is also conceivable for the main extension of the control to run along another axis and / or direction that appears appropriate to a person skilled in the art, for example at least substantially parallel to the central axis of the clamping unit and / or to the axis of rotation of the spindle. In the case of a course of the main extension formed parallel to the axis of rotation of the spindle, it is conceivable for the pin-shaped control element to engage in a control recess in which a ramp-like track is arranged. The control recess extends in a plane oriented parallel to the rotation axis main extension in a plane which is at least substantially perpendicular to a central axis of the transfer unit and / or to the axis of rotation of the spindle. It is conceivable here that the control element, in particular on a side facing the control recess, and the ramp-like raceway each have a sliding coating, so that a low friction between the raceway and the control element can be achieved. However, it is also conceivable that the spindle and arranged on the spindle transmission element of the transmission unit, in particular a form-fitting with the spindle connected transmission element, each having grooves and the control element to form an interface as in the grooves inserted rolling elements, in particular as a ball is formed. A design of the control element as a thread between the spindle and arranged on the spindle, in particular in direct contact with the spindle, transmission element for generating a relative movement along the axis of rotation of the spindle between a transmission element of the transmission unit and the spindle is also conceivable. Another embodiment of the control element which appears expedient to a person skilled in the art and / or the interface between the spindle and the transmission element is likewise conceivable. By means of the pin-shaped design of the control can advantageously be achieved a stable control. Furthermore, structurally simple, for example, a securing function, in particular for axial securing and / or rotational securing, the transmission unit can be achieved on the spindle.

Preferably, the control recess is arranged on a clamping element of the clamping unit. Particularly preferably, the control recess is arranged in the clamping element. In this case, the control recess is formed in particular by a groove. Preferably, the clamping element in the region of the control recess in comparison to a region adjacent to the control recess portion of the clamping element on a lower material thickness, in particular a material thickness of 0 mm. However, it is also conceivable that at least two ribs are arranged on an outer surface of the clamping element, in which the control element engages at least partially. The at least two ribs may in this case extend, in particular starting from the outer surface, at least substantially perpendicularly in the direction of the control element, so that the at least two ribs can form a guide for the control element. The control element preferably extends at least partially through the tensioning element in a region of the control recess. The term "extend through" is to be understood here in particular as meaning that the control element has a main extension along a direction extending at least substantially perpendicular to the center axis of the tensioning element, which is greater than an extent of the control recess along the direction extending at least substantially perpendicular to the central axis , It can be achieved prematurely a secure coupling of the control with the control recess and with the clamping element.

Advantageously, the cam mechanism has at least one spring element which is provided to bias at least one clamping element of the clamping unit relative to the control element. A "spring element" is to be understood here as meaning, in particular, an element which is elastically deformable under a load, wherein the element can store a potential energy and, after a discharge, can automatically return to its pre-stress state by means of the stored potential energy. The spring element is preferably designed as a tension spring and / compression spring. However, it is also conceivable that the spring element is formed by another, an expert appearing appropriate element. It can be advantageously achieved a structurally simple provision of the cam gear and / or the transmission element relative to the spindle in a starting position.

Furthermore, it is proposed that the control recess in one side of the clamping element has an extension along an angular range of less than 40 ° along a circumferential direction. Preferably, the control recess is arranged in the peripheral side of the clamping element along an angular range of less than 30 ° and particularly preferably along an angular range of less than 20 °. The peripheral side preferably runs concentrically around the central axis of the clamping unit. Particularly preferably, the peripheral side is at least partially formed by a lateral surface of a hollow cylindrical spindle receiving region of the clamping element. The circumferential direction preferably extends in a plane which extends at least partially perpendicular to the central axis of the clamping unit. Particularly preferably, the control recess along the circumferential direction on a mathematically defined slope in the axial direction. The pitch of the control recess corresponds in particular to 100 to 150% of a pitch of a thread between the clamping nut and the spindle, preferably 110 to 140% of the pitch of the thread between the clamping nut and the spindle and more preferably 120 to 130% of the pitch of the thread between the Clamping nut and the spindle. It can be advantageously achieved a compact safety device.

The invention is also based on a hand tool, in particular an angle grinder, with a hand tool clamping device according to the invention. It can be advantageously avoided a drainage of a tool from the spindle of the power tool.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown.

Fig. 1

eine Handwerkzeugmaschine mit einer erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 2

eine Detailansicht einer Spindel der Handwerkzeugmaschine aus Fig. 1 mit der an der Spindel angeordneten erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 3

eine Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung auf eine in einem montierten Zustand einem Werkzeug abgewandte Seite der Handwerkzeugmaschinenspannvorrichtung in einer schematischen Dastellung,

Fig. 4

eine Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung auf eine in einem montierten Zustand dem Werkzeug zugewandte Seite der Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 5

eine perspektivische Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einem geöffneten Zustand mit einem Schnitt entlang der Linie V-V aus Fig. 4,

Fig. 6

eine weitere perspektivische Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einem geöffneten Zustand mit einem Schnitt entlang der Linie V-V aus Fig. 4,

Fig. 7

eine perspektivische Detailansicht einer alternativen erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einem geöffneten Zustand mit einem analogen Schnitt gemäß der Linie V-V aus Fig. 4

Fig. 8

eine Schnittansicht entlang einer Rotationsachse einer Spindel der erfindungsgemäßen Handwerkzeugmaschinenvorrichtung in einer schematischen Darstellung,

Fig. 9

eine Schnittansicht entlang der Rotationsachse der Spindel der erfindungsgemäßen Handwerkzeugmaschinenvorrichtung nach einem Abschalten der Handwerkzeugmaschine in einer schematischen Darstellung und

Fig. 10

eine Detailansicht einer Steuerausnehmung eines Kurvengetriebes der Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung.

Show it:

Fig. 1

a hand tool with a hand tool clamping device according to the invention in a schematic representation,

Fig. 2

a detailed view of a spindle of the power tool from Fig. 1 with the hand tool clamping device according to the invention arranged on the spindle in a schematic representation,

Fig. 3

a detailed view of the hand tool clamping device according to the invention on a side facing away from the tool in a mounted state of the power tool clamping device in a schematic Dastellung,

Fig. 4

a detailed view of the hand tool clamping device according to the invention in a mounted state of the tool facing side of the power tool clamping device in a schematic representation,

Fig. 5

a detailed perspective view of the hand tool clamping device according to the invention in an open state with a section along the line VV Fig. 4 .

Fig. 6

a further perspective detail view of the hand tool clamping device according to the invention in an open state with a section along the line VV Fig. 4 .

Fig. 7

a detailed perspective view of an alternative hand tool clamping device according to the invention in an open state with an analogous section along the line VV Fig. 4

Fig. 8

a sectional view along a rotational axis of a spindle of the hand tool device according to the invention in a schematic representation,

Fig. 9

a sectional view along the axis of rotation of the spindle of the hand tool device according to the invention after switching off the power tool in a schematic representation and

Fig. 10

a detailed view of a control recess of a cam mechanism of the power tool clamping device in a schematic representation.

Description of the embodiments

FIG. 1 shows a trained as angle grinder 60a hand tool 62a with a hand tool clamping device 10a according to the invention in a schematic representation. The angle grinder 60a comprises a protective hood unit 64a, a hand tool housing 66a and a main handle 68a, which extends on a side facing away from a tool 14a side 70a in the direction of a main extension direction 72a of the angle grinder 60a. The portable power tool housing 66a comprises a motor housing 74a for receiving an electric motor (not shown here in detail) and a gear housing 76a for mounting a gear (not shown in detail here). On the gear housing 76a an additional handle 78a is arranged on the angle grinder 60a. The auxiliary handle 78a extends transversely to the main extension direction 72a of the angle grinder 60a.

FIG. 2 shows a detailed view of a spindle 16a of the machine tool 62a designed as an angle grinder 60a with the arranged on the spindle 16a hand tool clamping device 10a in a schematic representation. The spindle 16a extends perpendicular to the main extension direction 72a from the gear housing 76a (not shown here).

The hand tool clamping device 10a in this case has a clamping unit 12a, which is intended to clamp the disk-shaped tool 14a on the spindle 16a. The spindle 16a has two flats 82a on an outer periphery for receiving a receiving flange 80a, which are arranged diametrically and thus form a two-edge 84a. In this case, only one of the flats 82a is shown in FIG. The outer periphery of the spindle 16a is disposed in a plane perpendicular to a rotation axis 86a of the spindle 16a. However, it is also conceivable that the spindle 16a is tapered in a receiving area for the receiving flange 80a and the receiving flange has a receiving opening corresponding to the conical configuration, so that in a mounted state a conical seat is formed between the spindle 16a and the receiving flange 80a. The spindle 16a is rotatably driven about the axis of rotation 86a by means of the gear, not shown, and the electric motor, not shown, of the angle grinder 60a. In a working operation of the angle grinder 60a, the spindle 16a is rotated by the angle grinder 60a in a clockwise direction. Here, the power tool clamping device 10a is also driven in a mounted state rotating in a clockwise direction.

The clamping unit 12a of the hand-held power tool clamping device 10a comprises a first clamping element 22a and a second clamping element 24a (FIG. 2) movable relative to the first clamping element 22a (FIG. FIG. 5 ). The first clamping element 22a is disc-shaped. Furthermore, the first clamping element 22a has a contact surface 92a, which abuts the tool 14a in an assembled state. The tool 14a is pushed onto the spindle 16a in an assembly with a central opening along an axial direction 28a until the tool 14a bears against the receiving flange 80a. Subsequently, the clamping unit 12a is screwed by means of an internal thread 88a of the second clamping element 24a on a thread 90a of the spindle 16a until the contact surface 92a of the first clamping element 22a rests against the tool 14a. Thus, the tool 14a is clamped to the receiving flange 80a by means of the clamping unit 12a on the spindle 16a. The contact surface 92a of the first clamping element 22a and a voltage applied to the contact surface 92a side of the tool 14a may in this case an adhesive coating (not shown here), so that a friction between the contact surface 92a of the first clamping element 22a and at the Contact surface 92a adjacent side of the tool 14a is high. However, it is conceivable that the contact surface 92a and the voltage applied to the contact surface 92a side of the tool 14a have a corresponding ramp-like geometry, which engage with each other. Other friction-enhancing measures and designs of the contact surface 92a and the side of the tool 14a resting on the abutment surface 92a, which appear sensible to a person skilled in the art, are likewise conceivable.

By means of the tensioning of the tool 14a between the clamping unit 12a and the receiving flange 80a on the spindle 16a, a torque is transmitted from the spindle 16a to the tool 14a. The tool 14a is driven to rotate in a clockwise direction as viewed by the angle grinder 60a in the operation of the angle grinder 60a. In the operating mode of the angle grinder 60a, a clamping force of the clamping unit 12a is maintained for clamping the tool 14a due to friction between the clamping unit 12a and the abutting against the contact surface 92a side of the tool 14a. The first clamping element 22a has, on a side 174a facing away from the contact surface 92a, two rotational engagement recesses 176a, 178a into which a two-nut rotary key can engage to produce an up and / or unscrewing torque. The Drehitnahmeausnehmungen 176a, 178a in this case each have a central axis which extends in an assembled state of the power tool clamping device at least substantially parallel to the rotation axis 86a.

The angle grinder 60a includes a braking device (not shown in detail here) to avoid trailing the spindle 16a in a shutdown of the angle grinder 60a, for example by means of an interruption of a power supply. In the turn-off operation, the angle grinder 60a switches to a braking operation and brakes the spindle 16a by means of the brake device. In braking operation, the tool 14a moves further due to inertia in the clockwise direction or further about the axis of rotation 86a of the spindle 16a, so that a torque difference between the tool 14a, the spindle 16a and the clamping unit 12a arises. This torque difference leads to a relative movement between the tool 14a and the clamping unit 12a. Due to a friction between the clamping unit 12a and the sluggish tool 14a, the clamping unit 12a is opposite to a in the Operating operation of the angle grinder 60a generated rotation direction with the tool 14a rotated so that a by the slope of the internal thread 88a of the second clamping element 24a and the thread 90a of the spindle 16a generated thread bias can solve. In this way, a clamping force of the clamping unit 12a can be reduced and the clamping unit can run off together with the tool 14a of the spindle 16a.

In order to prevent the clamping unit 12a and / or the tool 14a from running out, the hand tool clamping device 10a has a run-off securing unit 18a, which comprises a movement changing unit 20a. The movement changing unit 20a is provided to at least partially convert a first relative movement between the first clamping element 22a and the second clamping element 24a of the clamping unit 12a into a second relative movement (FIG. FIG. 5 ). Here, the first relative movement between the first clamping element 22a and the second clamping element 24a is a rotation about the axis of rotation 86a. The second relative movement between the first clamping element 22a and the second clamping element 24a is a translation along the axial direction 28a. The rotation between the first clamping element 22a and the second clamping element 24a results in the braking operation from the torque difference between the tool 14a and the clamping unit 12a. The tool 14a rotates by the resulting friction between the tool 14a and the abutment surface 92a of the first clamping element 22a, the first clamping element 22a, wherein the second clamping element 24a is connected by means of the internal thread 88a with the spindle 16a. The first clamping element 22a is movably mounted in the second clamping element 24a, which is cup-shaped. The first clamping element 22a is movably mounted along a circumferential direction 58a and along the axial direction 28a in the second clamping element 24a.

The movement changing unit 20a is designed as a lifting unit 26a, which is provided to move the first clamping element 22a along the axial direction 28a as a result of the first relative movement, in particular the rotation, relative to the second clamping element 24a. The lifting unit 26a has three first lifting elements 30a, 32a, 34a, which are formed integrally with the first clamping element 22a. The three first lifting elements 30a, 32a, 34a are formed in a ramp shape. Furthermore, the lifting unit 26a has three second lifting elements 36a, 38a, 40a which, as a result of the first relative movement or the rotation of the first Clamping element 22a relative to the second clamping element 24a by means of cooperation with the first lifting elements 30a, 32a, 34a generate the second relative movement or the translation of the first clamping element 22a relative to the second clamping element 24a. The second lifting elements 36a, 38a, 40a are in this case also formed ramp-shaped. Furthermore, the second lifting elements 36a, 38a, 40a are integrally formed with the second clamping element 24a (FIG. 5). The first lifting elements correspond here to the second lifting elements 36a, 38a, 40a. However, it is also conceivable to provide a larger or smaller number than three first lifting elements 30a, 32a, 34a on the first clamping element 22a and three second lifting elements 36a, 38a, 40a on the second clamping element 24a. Depending on the requirement, the person skilled in the art will decide which number of lifting elements 30a, 32a, 34a, 36a, 38a, 40a on the first clamping element 22a and the second clamping element 24a seems to make sense. The first lifting elements 30a, 32a, 34a extend evenly distributed along a circular ring of 360 ° of the first clamping element 22a each along an angular range between 30 ° and 60 ° about a central opening 94a of the first clamping element 22a, which is provided for receiving the spindle 16a , The central opening 94a is formed here as a pass-hole.

The second lifting elements 36a, 38a, 40a extend evenly distributed along a circular ring of 360 ° of the second clamping element 24a each along an angular range between 30 ° and 60 ° about a central opening 96a of the second clamping element 24a, which is provided for receiving the spindle 16a ( FIG. 5 ). The second lifting elements 36a, 38a, 40a have, starting from an inner surface 98a of the second clamping element 24a in the direction of the first clamping element 22a, a mathematically defined pitch. The second lifting elements 36a, 38a, 40a in this case have a pitch corresponding to the first lifting elements 32a, 34a, 36a. The pitch of the first lifting elements 32a, 34a, 36a and the second lifting elements 38a, 40a, 42a is equal to or greater than a pitch of the thread 90a of the spindle 16a and the internal thread 88a of the second clamping element 24a. During rotation of the first tensioning element 22a relative to the second tensioning element 24a as a result of the braking operation, the first lifting elements 30a, 32a, 34a slide on the second lifting elements 36a, 38a, 40a. As a result, an axial stroke of the first clamping element 22a is generated relative to the second clamping element 24a along the axial direction 28a. This axial stroke causes a maintenance and / or an increase Clamping force between the internal thread 88a of the second clamping element 24a and the thread 90a of the spindle 16a, so that a drainage of the clamping unit 12a and / or the tool 14a can be prevented by the spindle 16a.

The hand tool clamping device 10a comprises three stop elements 42a, 44a, 46a, which are provided to limit the first relative movement between the first clamping element 22a and the second clamping element 24a and the rotation of the first clamping element 22a relative to the second clamping element 24a ( FIG. 5 ). The stop elements 42a, 44a, 46a are arranged on the first clamping element 22a facing inner surface 98a of the second clamping element 24a. The first clamping element 22a has three recesses 100a, 102a, 104a ( FIG. 6 ) intended to receive the stop members 42a, 44a, 46a. However, it is conceivable to provide a larger or smaller number than three stop elements 42a, 44a, 46a on the second clamping element 24a and three recesses 100a, 102a, 104a on the first clamping element 22a. Depending on the requirement, the person skilled in the art will decide which number of stop elements 42a, 44a, 46a on the second clamping element 24a and which number of recesses 100a, 102a, 104a on the first clamping element 22a would make sense.

The three stop elements 42a are uniformly distributed along the annulus of the second tensioning element 24a of 360 °, spaced from each other and spaced from the three second lifting elements 36a, 38a, 40a of the second tensioning element 24a. Furthermore, the three stop elements 42a, 44a, 46a have axial extensions that run along the axial direction 28a. The axial extensions are in this case selected such that the three stop elements 42a, 44a, 46a extend into the three recesses 100a, 102a, 104a of the first clamping element 22a. The three recesses 100a, 102a, 104a extend on the circular ring of 360 ° of the first clamping element 22a uniformly distributed in each case along an angular range between 15 ° and 30 ° and are spaced from each other and to the first lifting elements 30a, 32a, 34a about the central opening 94a of the first clamping element 22a arranged.

The stopper elements 42a, 44a, 46a limit the rotation between the first clamping element 22a and the second clamping element 24a to one by one Dimension of the recesses 100a, 102a, 104a and a dimension of the stop elements 42a, 44a, 46a defined angle range. As a result, a desired release of the clamping unit 12a is made possible, for example, during a tool change. When the clamping unit 12a is rotated by the angle grinding machine 60a in the clockwise direction or counter to the rotation direction in the working mode, the first clamping element 22a is rotated relative to the second clamping element 24a until the stop elements 42a, 44a, 46a of the first clamping element 24a at edge regions 106a, 108a, 110a of the recesses 100a, 102a, 104a of the first clamping element 22a strike. The first tensioning element 22a is fixedly connected to the second tensioning element 24a by abutment or abutment of the abutment elements 42a, 44a, 46a at the edge regions 106a, 108a, 110a of the recesses 100a, 102a, 104a.

Further, the power tool chuck 10a has a plurality of lubricant accommodating spaces 112a for receiving lubricant for reducing friction in the first relative movement between the first chuck 22a and the second chuck 24a. The lubricant accommodating spaces 112a are formed by lubricant pockets 114a. The lubricant pockets 114a are arranged uniformly spaced from one another along a circular ring around the central opening 94a of the first clamping element 22a ( FIG. 6 ). The lubricant pockets 114a are arranged in a side 116a of the first clamping element 22a facing away from the contact surface 92a. Further, in the ramp-like first lifting elements 30a, 32a, 34a and in the ramp-like second lifting elements 36a, 38a, 40a also lubricant pockets (not shown here) are arranged so that a low frictional resistance in a sliding of the ramp-shaped first lifting elements 30a, 32a, 34a arises on the ramp-shaped second lifting elements 36a, 38a, 40a during a rotation of the first clamping element 22a relative to the second clamping element 24a.

Furthermore, the second clamping element 24a has a bearing element 118a which is arranged in an annular recess 120a in the inner surface 98a of the second clamping element 24a. The bearing element 118a is formed here as a plain bearing. However, it is conceivable that the bearing element 118a is formed in an alternative embodiment as a rolling bearing. In the annular recess 120a are also a plurality of lubricant pockets (here not shown in detail) arranged to receive lubricant evenly spaced from each other. It is also conceivable that the Lagerelemtent 118a is made of an elastic, such as a resilient material, and is taken along the axial direction 28a biased in the annular recess 120a of the second clamping element 24a. In this way, a surface pressure between the first lifting elements 30a, 32a, 34a and the second lifting elements 36a, 38a, 40a can be reduced, so that a low friction between the first lifting elements 30a, 32a, 34a and the second lifting elements 36a, 38a, 40a are achieved can. Furthermore, by forming the bearing element 118a from an elastic material, a provision of the first clamping element 22a relative to the second clamping element 24a can be achieved as soon as one of the first clamping element 22a and the second clamping element 24a is in an at least substantially unloaded state, such as for example Disassembly of the spindle 16a, are located.

The clamping unit 12a further comprises a first sealing element 122a and a second sealing element 124a, which are provided to protect the clamping unit 12a from dust ingress from an external environment and to prevent lubricant leakage from the inside. In this case, the first sealing element 122a is arranged in a first groove 126a of the second clamping element 24a, and the second sealing element 124a is arranged in a second groove 128a of the second clamping element 24a ( FIG. 5 ). The first groove 126a is disposed in a side surface 130a of the second tension member 24a. The side surface 130a extends perpendicular to the inner surface 98a of the second clamping element 24a and along an entire circumference of the second clamping element 24a, which extends in a plane parallel to the inner surface 98a. The second groove 128a is arranged in a side 132a, facing the side surface 130a, of a hollow cylinder 134a surrounding the central opening 96a of the second clamping element 24a. The first sealing element 122a is press-fit into the first groove 126a and the second sealing element 124a is press-fit into the second groove 128a.

The first clamping element 22a also has a first groove 136a for receiving the first sealing element 122a. The first groove 136a of the first clamping element 22a is disposed along an outer periphery of the first clamping element 22a and extends along the entire outer circumference. The outer circumference of the first clamping element 22a extends in a plane which extends at least substantially parallel to the contact surface 92a. Here, the first groove 136a has an extension along the axial direction 28a, which is greater than an extension of the first sealing element 122a along the axial direction 28a. This ensures a sealing function during an axial stroke of the first clamping element 22a relative to the second clamping element 24a.

Furthermore, the first clamping element 22a for receiving the second sealing element 124a has a second groove 138a of the second clamping element 24a. The second groove 138a is disposed in an inner side 140a of the central opening 94a of the first biasing member 22a and extends along an entire circumference of the central opening 94a. The circumference of the central opening 94a extends in a plane which extends at least substantially parallel to the contact surface 92a of the first clamping element 22a. The second groove 138 a has an extension along the axial direction 28 a, which is greater than an extension of the second sealing element 124 a along the axial direction 28 a. As a result, a sealing function is likewise ensured in the case of an axial stroke of the first clamping element 22a relative to the second clamping element 24a. By means of the first sealing element 122a and the second sealing element 124a, the first clamping element 22a and the second clamping element 24a are connected to one another and axially fixed.

In FIGS. 7 to 10 two alternative embodiments are shown. Substantially identical components, features and functions are basically numbered by the same reference numerals. To distinguish the embodiments, the letters a to c are added to the reference numerals of the embodiments. The following description is limited essentially to the differences from the first embodiment in the FIGS. 1 to 6 , wherein with respect to the same components, features and functions on the description of the first embodiment in the FIGS. 1 to 6 can be referenced.

FIG. 7 shows a perspective detail view of an alternative Handwerkzuegmaschinenspannvorrichtung invention 10b in an open state with an analog section along the line VV Fig. 4 , The Handwerkzuegmaschinenspannvorrichtung 10b comprises a clamping unit 12b, which is intended to clamp a tool 14b on a spindle 16b. The clamping unit 12b includes a first clamping element 22b and a relative to the first clamping element 22b movable second clamping element 24b. Furthermore, the hand tool clamping device 10b comprises a run-off securing unit 18b for preventing the clamping unit 12b and / or the tool 14b from running out of the spindle 16b. The flow control device 18b has a movement change unit 20b embodied as a lifting unit 26b, which is provided to convert a first relative movement between the first clamping element 22b and the second clamping element 24b into a second relative movement in a braking mode.

The lifting unit 26b has three first lifting elements 30b, 32b, 34b, which are arranged on a side 116b of the first clamping element 22b facing away from a contact surface 92b. Furthermore, the lifting unit 26b has three second lifting elements 36b, 38b, 40b, which are formed integrally with the first clamping element 22b. The second lifting elements 36b, 38b, 40b are formed in a ramp shape. The first lifting elements 30b, 32b, 34b are formed as rolling elements 142b, 144b, 146b. The rolling bodies 142b, 144b, 146b are arranged in recesses 148b, 150b, 152b in the side 116b of the first clamping element 22b facing away from the contact surface 92b. The recesses 148b, 150b, 152b are evenly distributed along a circular ring and spaced from one another in the first clamping element 22b. The rolling elements 142b, 144b, 146b of the first clamping element 22b correspond to the ramp-shaped second lifting elements 36b, 38b, 40b of the second clamping element 24b. However, it is conceivable that in an alternative embodiment, the first lifting elements 30b, 32b, 34b are integrally formed on the first clamping element 22b and the second lifting elements 36b, 38b, 40b are formed as rolling elements and are arranged in recesses in the second clamping element 24b. Upon rotation of the first tension member 22b relative to the second tension member 24b due to a braking operation, the rolling elements 142b, 144b, 146b roll along the ramp-shaped second lift members 36b, 38b, 40b, thus generating an axial stroke along an axial direction 28b of the first tension member 22b relative to the second tension member 24b.

FIG. 8 shows another alternative hand tool clamping device 10c. The hand tool clamping device 10c has a clamping unit 12c, which is provided to clamp a tool 14c in the axial direction 28c on a spindle 16c. To prevent the tensioning unit 12c and / or the tool 14c from running out of the spindle 16c in a braking mode, the hand-held power tool clamping device has a running position 10c on a flow assurance unit 18c. The sequence assurance unit 18c comprises a movement change unit 20c, which is provided to convert a first relative movement between a first clamping element 22c and a second clamping element 24c of the clamping unit 12c into a second relative movement during braking operation. The movement changing unit 20c is designed as a lifting unit 26c, which is provided to generate at least one relative movement of the first clamping element 22c relative to the second clamping element 24c along the axial direction 28c during braking operation. The lifting unit 26c is designed as a cam mechanism 154c which has two lifting elements 30c, 32c designed as control recesses 48c, 50c, in each of which one of two control elements 52c, 54c of the cam gear 154c engages. However, it is also conceivable for the cam mechanism 154c to have another number of control elements 52c, 54c, which appears meaningful to a person skilled in the art, and to control recesses 48c, 50c. A person skilled in the art will provide, depending on the application, a suitable number of control elements 52c, 54c and control recesses 48c, 50c.

The controls 52c, 54c are movably disposed in the control recesses 48c, 50c. Further, the controls 52c, 54c are formed pin-shaped. In this case, the control elements 52c, 54c are each fixed by means of a press fit in one of two recesses 158c, 160c of the second clamping element 24c. However, it is also conceivable that the control elements 52c, 54c are fixed to the spindle 16c by means of another type of connection that appears appropriate to a person skilled in the art, for example by means of a non-positive and / or a material connection. The recesses 158c, 160c are arranged diametrically opposite one another on a side 162c of the second clamping element 24c extending along a circumferential direction 58c. Thus, the recesses 158c, 160c along the circumferential direction 58c are arranged evenly distributed on the second clamping element 24c. The control recesses 48c, 50c of the cam gear 154c are arranged on the first clamping element 22c. In this case, the control recesses 48c, 50c have an extension along an angular range of approximately 20 ° along the circumferential direction 58c in a side 156c of the first clamping element 22c extending along the circumferential direction 58c. Furthermore, the control recesses 48c, 50c viewed along the circumferential direction 58c, a mathematically defined slope in the axial direction 28c. The control elements 52c, 54c extend from the second clamping element 24c into the control recesses 48c, 50c.

The control elements 52c, 54c are provided by means of cooperation with the control recesses 48c, 50c to convert a first relative movement between the first clamping element 22c and the second clamping element 24c of the clamping unit 12c into a second relative movement during braking operation of the angle grinder 60c. The first clamping element 22c is in this case due to a rotational movement relative to the second clamping element 34c and relative to the spindle 16c translationally relative to the second clamping element 34c along a rotation axis 86c of the spindle 16c in the direction of the tool 14c moves. The translational movement along a distance x of the first clamping element 22c is limited by a dimension of the control recesses 48c, 50c.

In a working operation of the angle grinder 60c, the control elements 52c, 54c are each arranged in a tool-side region 164c of the control recesses 48c, 50c. The first clamping element 22c and the second clamping element 24c in this case bear against a side 166c of the tool 14c facing the clamping unit 12c. However, it is also conceivable for the second clamping element 24c to be arranged at a distance from the side 166c of the tool 14c facing the clamping unit 12c and only the first clamping element 22c to abut the clamping unit 12c on the side 166c of the tool 14c. A contact surface 92c of the first clamping element 22c which bears against the clamping unit 12c on the side 166c of the tool 14c is provided with an adhesive coating which has a high coefficient of friction. The clamping unit 12c facing side 166c of the tool 14c is also provided with an adhesive coating. In this way, a rotational drive can be ensured during a run and / or during braking operation.

The rotation between the first clamping element 22c and the second clamping element 24c arises during braking operation from the torque difference between the tool 14c and the clamping unit 12c. The tool 14c rotates the first clamping element 22c by the resulting friction between the tool 14c and a contact surface 92c of the first clamping element 22c. By means of the engagement of the control elements 52c, 54c in the control recesses 48c, 50c and the pitch of the control recesses 48c, 50c, the first clamping element 22c moves translationally along the axial direction 28c as a result of the rotation relative to the second clamping element 24c. The first clamping element 22c exerts a force along the axial direction 28c on the tool 14c. The tool 14c is thus pressed against the spindle 16c along the axial direction 28c, so that a clamping force in the thread 90c of the spindle 16c and in the internal thread 88c of the second clamping element 24c is maintained and / or increased. In this way, a release of the tool 14c and thus a running of the tool 14c and / or the clamping unit 12c can be prevented in the braking operation.

As a result of the first relative movement between the first clamping element 22c and the second clamping element 24c within the control recesses 48c, 50c, the control elements 52c, 54c are moved in the direction of a clamping element-side region 168c of the control recesses 48c, 50c by means of a torque difference between the tool 14c and the clamping unit 12c emotional. The tension member side portion 168c of the control recesses 48c, 50c are respectively disposed on a side of the control recesses 48c, 50c facing the second tension member 24c. Here, the second clamping element 24c is decoupled from the clamping unit 12c facing side 166c of the tool 14c. When the control elements 52c, 54c abut against the machine-side region 168c of the control recesses 48c, 50c, the first clamping element 22c has traveled the distance x along the axial direction 86c. The control elements 52c, 54c have also traveled the distance x with respect to the tool-side region 164c of the control recesses 48c, 50c along the axial direction 66b. Thus, the translational movement of the first chuck 22c is limited by a distance of the tool-side portion 164c and the chuck-side portion 168c along the pitch of the control recesses 48c, 50c. FIG. 10 ).

To ensure torque transmission and / or force transmission between the first tension member 22c and the tool 14c in a braking operation, the cam gear 154c has two spring members 56c provided to bias the first tension member 22c against the controls 52c, 54c (in FIG Figur10 only a spring element shown). The spring elements 56c are designed as tension springs 172c. It is, however It is conceivable that the spring elements 56c are formed in another form which appears expedient to a person skilled in the art, for example as elastomer elements or the like. The tension springs 172c are respectively disposed in one of the control recesses 48c, 50c along the circumferential direction 58c, between the tool side portion 164c of the control recesses 48c, 50c and the control member 52c, 54c engaged in the respective control recess 48c, 50c. The tension springs 172c thus act on the first tensioning element 22c with spring forces along the circumferential direction 58c. The first clamping element 22c is biased in the direction of the second clamping element 24c due to the spring forces of the tension springs 172c. The clamping unit 12c is thus returned to a basic position in a substantially unloaded state, so that the relative movements between the first clamping element 22c and the second clamping element 24c can be reliably carried out in the braking mode.

The first clamping element 22c further has on a second clamping element 24c facing surface 170c lubricant receiving elements (not shown here), which are provided to allow a relative movement between the first clamping element 22c and the second clamping element 24c with low friction. It is also conceivable that the lubricant receiving elements are arranged on the second clamping element 24b or are arranged both on the first transmission element 22c and on the second clamping element 24c.

The hand tool clamping device 10c comprises two stop elements 42c, 44c, which are provided to limit the first relative movement between the first clamping element 22c and the second clamping element 24c and the rotation of the first clamping element 22c relative to the second clamping element 24c. The stop elements 42c, 44c are each formed by one end of a dimension of the control recesses 48c, 50c, on which the control element 52c, 54c in a rotation of the first clamping element 22c realtiv strikes the second clamping element 24c when reaching an end position.

Claims (10)

1. Clamping device for a hand-held machine tool with at least one clamping unit (12a; 12b; 12c) which is provided for clamping a tool (14a; 14b; 14c) on a spindle (16a; 16b; 16c), wherein the clamping unit (12a; 12b; 12c) is provided for clamping the tool (14a; 14b; 14c) axially on the spindle (16a; 16b; 16c) against a receiving flange (80a; 80c), and with at least one detachment protection unit (18a; 18b; 18c) for avoiding detachment of the clamping unit (12a; 12b; 12c) and/or of the tool (14a; 14b; 14c) from the spindle (16a; 16b; 16c), wherein the detachment protection unit (18a; 18b; 18c) has at least one movement changing unit (20a; 20b; 20c) which is provided in order, in a braking mode, to at least partially convert a first relative movement between at least two clamping elements (22a, 24a; 22b, 24b; 22c, 24c) of the clamping unit (12a; 12b; 12c) into a second relative movement, wherein the first clamping element (22a; 22b; 24c) is mounted in the second clamping element (24a; 24b; 22c) so as to be movable along a circumferential direction (58a; 58b; 58c) and along an axial direction (28a; 28b; 28c), characterized by at least one stop element (42a, 44a, 46a; 42b, 44b, 46b; 42c, 44c) which is provided to limit at least one relative movement between the two clamping elements (22a, 24a; 22b, 24b; 22c, 24c).
2. Clamping device for a hand-held machine tool according to Claim 1, characterized in that the movement changing unit (20a; 20b; 20c) is designed as a lifting unit (26a; 26b; 26c) which is provided in order, in the braking mode, to produce at least one relative movement of the two clamping elements (22a, 24a; 22b, 24b; 22c, 24c) along an axial direction (28a, 28b, 28c).
3. Clamping device for a hand-held machine tool according to Claim 2, characterized in that the lifting unit (26a; 26b; 26c) has at least one lifting element (30a, 32a, 34a, 36a, 38a, 40a; 30b, 32b, 34b; 32c, 34c) which is at least partially formed integrally with one of the two clamping elements (22a, 24a; 22b, 24b; 22c, 24c).
4. Clamping device for a hand-held machine tool according to Claim 3, characterized in that the lifting element (30a, 32a, 34a, 36a, 38a, 40a; 30b, 32b, 34b; 30c, 32c) is of ramp-shaped design.
5. Clamping device for a hand-held machine tool according to one of Claims 2 to 4, characterized in that the lifting unit (26c) is designed as a cam mechanism (154c) which has at least one lifting element (30c, 32c) which is designed as a control recess (48c, 50c) and in which at least one control element (52c, 54c) of the cam mechanism (154c) at least partially engages.
6. Clamping device for a hand-held machine tool according to Claim 5, characterized in that the control element (52c, 54c) is of pin-shaped design.
7. Clamping device for a hand-held machine tool at least according to Claim 5, characterized in that the control recess (48c, 50c) is arranged on a clamping element (22c) of the clamping unit (12c).
8. Clamping device for a hand-held machine tool according to Claim 7, characterized in that the cam mechanism (154c) has at least one spring element (56c) which is provided for pretensioning at least one clamping element (24c) of the clamping unit (12c) relative to the control element (52c, 54c).
9. Clamping device for a hand-held machine tool at least according to Claim 7, characterized in that the control recess (48c, 50c) in one side (156c) of the clamping element (24c) has an extent along an angular range of less than 40° along a circumferential direction (58c).
10. Hand-held machine tool, in particular angle grinder, with a clamping device for a hand-held machine tool according to one of the preceding claims.

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